Rolling with good Precautions-Wenzhou Bearing wholesale

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Bearing Knowledge

Rolling with good Precautions

点击数：6173 日期：2014/4/4

Use the matters needing attention in rolling bearing: Rolling bearing is a kind of precision mechanical support components, bearing the user sincere hope mounted on a host to scheduled use period are not damaged and to maintain its dynamic performance, but the objective fact and sometimes not just as one wishes, failure would cause significant loss to the user sudden bearing. Through the rolling bearing failure analysis of a large number of studies show that, bearing longevity shortening or premature loss of precision, either due to material defects or improper manufacturing, but to a large extent, is due to not strictly in accordance with the bearing requirements, maintain, or cause bearing improper selection or actual load exceeds the rated load of the bearing itself. Non normal damage, cause bearing for example, fatigue spalling of bearing parts is largely because the lubricating oil mixed with impurities caused by. Therefore, in order to achieve the accuracy and service life of rolling bearing has a longer retention period, in addition to the requirements of the bearing manufacturers improve product quality, bearing the user must use scientific methods and procedures using bearings, otherwise, bearing good will die in the harsh use arbitrary conditions. The first chapter selection and substitution of rolling bearing Method and selected in step 1 The correct choice of rolling bearing, the host can obtain good performance, prolong the service life; the enterprises can shorten the repair time, reduce repair costs, improve the operation of machine rate, plays a very important role. Therefore, whether it is design and manufacture units, or repair using unit, in the choice of rolling bearings must attach great importance to the selection, all the procedures shown in figure 1&#0; 1. In general, selection of bearing steps may include: 1 according to the working conditions of bearing (including the loading direction and load type, speed, lubrication, coaxial, location or non positioning, installation and repair the environment, environmental temperature etc.), basic type, grade of tolerance and clearance of bearing; 2 according to the requirements of the bearing working conditions and state of stress and life, determined by calculating the bearing type, or according to the use requirements, selected bearing model, then check the life; Rated load and the speed limit is 3 checking the bearing. The main factor to consider when selecting a bearing is the speed limit, dacron life and load capacity, other factors help to determine the bearing type, structure, size and grade of tolerance and clearance for the final solution. 1 types of selection Use the matters needing attention in rolling bearing: Rolling bearing is a kind of precision mechanical support components, bearing the user sincere hope mounted on a host to scheduled use period are not damaged and to maintain its dynamic performance, but the objective fact and sometimes not just as one wishes, failure would cause significant loss to the user sudden bearing. Through the rolling bearing failure analysis of a large number of studies show that, bearing longevity shortening or premature loss of precision, either due to material defects or improper manufacturing, but to a large extent, is due to not strictly in accordance with the bearing requirements, maintain, or cause bearing improper selection or actual load exceeds the rated load of the bearing itself. Non normal damage, cause bearing for example, fatigue spalling of bearing parts is largely because the lubricating oil mixed with impurities caused by. Therefore, in order to achieve the accuracy and service life of rolling bearing has a longer retention period, in addition to the requirements of the bearing manufacturers improve product quality, bearing the user must use scientific methods and procedures using bearings, otherwise, bearing good will die in the harsh use arbitrary conditions. The first chapter selection and substitution of rolling bearing Method and selected in step 1 The correct choice of rolling bearing, the host can obtain good performance, prolong the service life; the enterprises can shorten the repair time, reduce repair costs, improve the operation of machine rate, plays a very important role. Therefore, whether it is design and manufacture units, or repair using unit, in the choice of rolling bearings must attach great importance to the selection, all the procedures shown in figure 1&#0; 1. In general, selection of bearing steps may include: 1 according to the working conditions of bearing (including the loading direction and load type, speed, lubrication, coaxial, location or non positioning, installation and repair the environment, environmental temperature etc.), basic type, grade of tolerance and clearance of bearing; 2 according to the requirements of the bearing working conditions and state of stress and life, determined by calculating the bearing type, or according to the use requirements, selected bearing model, then check the life; Rated load and the speed limit is 3 checking the bearing. The main factor to consider when selecting a bearing is the speed limit, dacron life and load capacity, other factors help to determine the bearing type, structure, size and grade of tolerance and clearance for the final solution. 1 types of selection With different characteristics of various types of rolling bearing, different using conditions applicable to all kinds of machinery. When selecting the type of bearing, Usually should consider the following factors. General: the thrust load selection of thrust bearing, angular contact bearings, usually use ball bearings for high speed applications, bear radial load heavy, choose roller bearing. In a word, bearing product selection of personnel from different manufacturers, numerous, choosing appropriate type. ? bearing occupied machinery space and place In the mechanical design, the general first determine the shaft size, then, according to the axial size selection of rolling bearing. Usually a small shaft using ball bearings, shaft selection of roller bearing. However, when the bearing is restricted in the direction of the diameter of the machine, is made of needle roller bearings, extra light and ultra light series of ball or roller bearings; when the bearing is restricted in the axial position of the machine, can choose the ball or roller bearing narrow or extra narrow series. The size, direction and nature? Bearing load Load is the main factor of the selected bearing. Roller bearings in the bearing heavy load, ball bearings to withstand mild or moderate load, bearing steel manufacturing or bainite quenching, can withstand the shock and vibration loads. In the direction of load, pure radial load bearing, can choose the deep groove ball bearings, cylindrical roller bearings or needle roller bearings. Pure axial load bearing small, can choose the thrust ball bearings; subject to pure axial load greatly, can choose the thrust roller bearing. When the bearings bear radial and axial load, general selection of angular contact ball bearing or tapered roller bearing. Self-aligning bearing performance? When the shaft and the bearing seat center line center line is different, the angle error, or because of the rigid two support spacing is larger and axis in small, easy bending or tilt, can be selected with good aligning performance self-aligning ball or roller bearings, and ball bearing. This kind of bearing in shaft slightly inclined or curved case, can keep the normal work. Bearing self-aligning performance, different axis associated with the different axes is allowed, the bigger value, aligning performance is better. All kinds of bearing allows different axis table 1&#0; 1 The rigidity of the bearing? The rigidity of the bearing, bearing size refers to the unit deformation force required for the. Rolling bearing elastic deformation is small, in most machines do not have to consider, but in some machines, such as the spindle, bearing rigidity is an important factor, should generally be used for cylindrical and conical roller bearing. Because these two types of bearings in the bearing load, the rolling belongs to the point contact, poor rigidity. In addition, all kinds of bearing can preload, increase the supporting rigidity of purpose. If the angular contact ball bearings and tapered roller bearings, in order to prevent the vibration of the shaft, increase the support rigidity, often in the installation of pre applied certain axial force, the pressing. Here is particularly pointed out that: the pre tension is not too large. Is too large, will make the bearing friction increases, temperature rise, affect the service life of bearing. Bearing speed? Each bearing models have the limit speed of its own, it is decided by such as size, type and structure, physical characteristics, the speed limit is bearing the highest working speed (usually R / min), beyond this limit will result in bearing temperature, lubricant dry, even the bearing card die. Use the occasion required speed range with the bearing, to help decide what type 1&#0; 2 typical speed range of the most common bearing. D is the size of bearing, it usually refers to the pitch circle diameter of bearings, in the choice of bearings, bearing inner and outer diameter of the average value, the unit mm With the diameter of D times the shaft rotational speed (r/min) reached a speed limit factors (DN, DN) is very important in the selection of bearing type and size. Most bearing manufacturers products directory provides the speed limit the product value, practice has proved, operating at less than the speed limit of 90% state is better. Grease lubrication bearing limit speed than the speed limit bearing lubrication oil low, oil bearing has an effect on the speed limit can be reached. Table 1&#0; 2 provides the speed limit bearing lubrication form several correction factor (K). We must pay attention to, the grease lubricated bearings, the speed limit is generally only is the speed limit of a high quality to repeat the cycle oil system adopts the bearing of 80%, but the oil mist lubrication system, the speed limit is generally higher than the same high 50% basic lubrication system. Keep design and structure also affects the limit speed of the bearing, because the rolling body and the holder is in sliding contact with the surface, more expensive, reasonable design, high quality and low friction material cage, rolling body not only can be separated, but also help the lubricating oil to maintain the sliding contact region the film. But like stamping cage like cheap cage, usually only the rolling body retainer separation. Therefore, they are prone to sliding contact accident and painful, which leads to lower the speed limit. Generally speaking in the workplace should be selected under high speed, deep groove ball bearings, angular contact bearings, cylindrical roller bearings; at low speed work occasions, can choose the tapered roller bearing. The speed limit of the tapered roller bearings, deep groove ball bearings in general is about 65%, the 70% cylindrical roller bearings, angular contact ball bearing 60%. The speed limit for the thrust ball bearing is low, can only be used for low speed occasion. For the same kind of bearing, the size is smaller, allowing higher speed. In the selection of bearing, should pay attention to the actual speed is lower than the limit speed. Bearings and axial displacement of swimming? Typically, a shaft, a certain distance with the two bearing support. In order to adapt to the different heat degree of shaft and housing prices, should be installed in a bearing in the axial direction is fixed, another bearing can be on the shaft walks (i.e. floating support), in order to prevent the axial elongation or contraction caused by clamping phenomenon. Floating support usually choose the inner or outer cylindrical roller bearings without flanges (the original type 2000, type 32000) and needle roller bearings, which is mainly the internal structure of the bearing shaft with appropriate axial displacement and shell. At this time, the inner ring and the shaft, the outer ring and shell hole can adopt a tight fit. When using a non separable bearing floating support, such as deep groove ball bearings, spherical roller bearings, must allow the outer ring and shell hole in the installation, or the inner ring and shaft adopts a loose fit, so that the axial free swimming. Figure 1&#0; 3 shows several positioning and non orientation of cylindrical roller bearing structure Taper roller bearing, spherical roller bearing and deep groove ball bearing basically belongs to the location type, when used as a non positioning is a loose fit. All are positioning thrust roller bearing type bearing. ? easy assembly and disassembly of bearing Selection of bearing type, bearing installation is convenient for disassembly, must also be considered, especially the installation and removal of large and extra large type bearing is very important. The outer ring can be separated angular contact ball bearings, tapered roller bearings, cylindrical roller bearings and needle roller bearings, installation and disassembly are convenient, the inner ring and the outer ring can be respectively arranged on the shaft or housing bore. In addition, with a tapered hole diameter, with compact spherical roller bearings, double row cylindrical roller bearings, self-aligning ball bearing sleeve, easier installation and disassembly. Other requirements? In addition to the above factors, also should consider the working environment temperature, bearing seal and the frictional torque, vibration, noise and other special requirements. 1 clearance selection Clearance is an important factor in rolling bearing can work normally, divided into the axial clearance and the radial clearance. Select the appropriate clearance, can make the load in the bearing rolling body between the reasonable distribution; can limit axis (or shell) of the axial and radial displacement, ensure the rotating precision of shaft; the bearing work at a prescribed temperature; reduce the noise and vibration, to improve the bearing life. Therefore. In the selection of bearings, bearing clearance, must choose the appropriate. Selection of bearing clearance, should consider the following aspects: 1 bearing working conditions, such as load, temperature, speed etc.; 2 pairs of bearing performance requirements (rotation accuracy, friction torque, vibration, noise); 3 bearing and shaft and housing bore is in interference fit with the lead to reduction of bearing clearance; The inner and outer rings of 4 bearings, the difference of temperature caused reduction of bearing clearance; 5 because the expansion coefficient of shaft and housing materials is different, resulting in the decrease or increase of bearing clearance. According to experience, the most suitable for ball bearing clearance work to nearly zero; roller bearing should keep a small amount of clearance. At the request of supporting rigid good parts, bearing preload has certain value. Here is particularly pointed out that, the so-called clearance refers to the bearing clearance, in the actual operating condition. There is also a play called the original clearance, refers to the bearing without clearance. The original clearance than installation clearance. We choose to play, mainly is to choose appropriate clearance. Clearance of national standard values were divided into three groups: basic group (group 0), small clearance assisted group (1, 2) and (3, 4 clearance auxiliary group, group 5). When the choice, under normal operating conditions, should be preferred base group, can make the bearings to get a proper job clearance. When the basic group can not meet the requirements, should choose assisted group clearance. Big clearance auxiliary group is suitable for bearing and shaft and housing bore by interference fit, a larger temperature difference between inner and outer rings of the bearing, deep groove ball bearings to bear large axial load or the need to improve the aligning properties, heart and requirements to improve the speed and reduce the friction torque of bearings and so on; the axial displacement of small clearance auxiliary for the rotation accuracy, higher requirements should be strictly controlled shell hole, and the need to reduce vibration and noise. The radial clearance of bearing the provisions of national standards. 1 grade of tolerance selection Public class bearing, mainly according to the axis of rotation accuracy to support requirements to determine the. Under normal circumstances, such as spur gear with big mesh tolerances of the reducer, the available PO bearing, but some of the rotating precision has strict requirements or the high speed shaft of machine tool spindle, such as high precision, small beating should choose bearing than PO grade. Bearing tolerance grade high, manufacturing tolerance of the axis of the shell should be matched with the bearing tolerance grade, and should have enough stiffness of structures. Table 1&#0 3 lists; bearing tolerance grade selection case, for reference. The calculation of 2 life and reliability The service life of the L requirements are determined according to the total expected time of equipment can work, commonly used unit is the number of hours worked, life is also calculated speed available bearing general representation, in the calculation of a lifetime, every state must be considered. The equipment is eight hour or day? It is used continuously throughout the day? It is the frequent start stop or start on long-term work? Table 1&#0; 4 gives the general service life of various power transmission application value. Repair costs, life expectancy and scrap must also be considered, is the equipment after long-term use replaced or repaired regularly (including replacement of bearings) cost more to save? Of course, life of L required in the decision, the reliability of bearings is a major consideration, reliability standards in bearing industry usually specified as 90%, that is to say, the bearing a lot of work in the same application occasions, 90% of the bearing at the selected set (the working life of bearing L life) is still intact, if the failure rate is low, the life of L requirements need to add correction. To improve the reliability of bearings, make its more than 90% reliability, reduce the service life of 10% failure rate can be used to solve the standard bearing. In other words, if you want to get higher reliability, standard bearing life must be reduced. For example: on a reliability of 96% bearings, must define the bearing life is L, not L. Without increasing the size of bearing condition, you must reduce the original L bearing life. At the back we will design are given. The bearing capacity, it is the function of velocity, the actual bearing load and the design life. In the applications given, speed and load is given, therefore the dynamic loading capacity is a function of the design life. In order to improve the reliability of 96%, you can increase the bearing dimensions, so as to achieve the same level of reliability for the 90% time, that is to say you can improve the dynamic bearing capacity, reliability and make it more than 90% of the required value, this needs a larger bearing selection. Table 5 gives the percentage of 1&#0; modified life. Where L is the bearing life standard 10% failure, in the left column, is the requirement of reliability failure rate, transverse to the corresponding read modify percentage, which is the percentage of standard L life, it is very useful in improving bearing reliability requirements. For example, if the population carrying capacity failure rate for 4% of your requirements of bearing, working life over 1000 hours, in order to achieve these requirements given in the table, the percentage of normal life correction for L bearing life 53%. Correction by the percentage of life divided by the requirement, which can have L: 1000/0. 53=1887 (H) The results show that: in order to obtain 96% reliability required 1000 hours, bearing life corresponding to 90% reliability when it is introduced the dynamic equation used to calculate the bearing capacity of bearing size is valuable. Calculation of load and equivalent load In order to meet the identified bearing load rating requirements, must have to force all bear to equipment is considered, and the corresponding time in the given period of each force acting on the bearing. A variety of circumstances or bearing operating conditions to form can be classified into. Note, the bearing load unit with N, speed unit with r/min, the expression of the effective time percentage in each case within a predetermined time in the life of bearing. These can be simplified into an equivalent load of P, and then, in each case to determine the equivalent load with the appropriate equation. If in the whole running period, speed and load is constant, the equivalent load is the load calculation: P =P equation (A) If in a long period, the velocity is constant, the load P gradually to a maximum value of P from the minimum value, then: If given a finite period, the velocity is constant, the load change is non-linear (is a step function or power function, combined sine function, or some function), in the whole life period, this kind of nonlinear random changes to repeat, then: The P, P,,,,, P represents at the selected time interval T, t,,,,, the load during t. Note, P, P,,,,, the formula of P value must be in one or a few (A) or (B) calculation. If the load and speed changes, and every change of load are accompanied by changes in the speed, then: The P, P,,,,, P, N, speed of N, N, the load, Q, Q, P, Q,, said to N, P to N,,,,, P activity in the n when the percentage of time. So, the speed has been included in the equation, so life should be calculated by the formula of life: Equation (E) of the coefficients in the "500" is the time value of 500 hours, it is based on the international standards of rotate speed is 33 /min as the basis, the equivalent of 500 hours of bearing life. Correction of equivalent load Many occasions subjected to vibration, the bearing stress increase. Similarly, including initial and permanent different axis, many applications, require significantly improve the load capacity. Vibration load is compensated by the vibration force corresponding (consider the worst case or the maximum vibration load) as compared to the radial load normal, stable it. Correction coefficients K must as a coefficient of equivalent load in the equation. Table 1&#0 lists the two coefficient; 6 conditions: one is K, the vibration force of P for P is higher than that of the stable load according to, P; another is K, based on P according to P P, big day. Table In need of special attention, bearing heavy load, but not the movement of the working conditions are particularly dangerous, because in the rolling body and the rings on the capacity to form micro indentation, have a strong impact, like a car tire rolling over potholes. Such as the crater like small indentation can quickly develop into pitting in the work process, resulting in bearing failure. The other extreme conditions exactly the opposite, namely high speed but the load is very small. If not applying a preload, the rolling body raceway on large sliding, which can lead to rapid overheating, lubricant decomposition failure and permanent damage. In the bearing selection is often ignored an important load consider is the equipment itself, radial and axial force. The gear weight and the other parts of the tension even shaft heavyweight are important stress with the total load. To determine the rated load capacity is required Now, the use right life, equivalent load, shaft speed and improve the reliability of any correction coefficient can be used together to load bearing capacity calculation of required. Where: C= required rated dynamic load capacity, N The requirements of L= L life, H N= shaft speed, r/min Equivalent load P = bearing, N The dimensionless index rolling contact type θ = Point contact (ball bearing) or line contact (roller bearings). The ball bearing: theta =3. 00. The roller bearings: theta =3.33. Assuming uniformly distributed in the surface of the rolling body force, the C value can be calculated. However, in the power transmission equipment, different axis is a common problem. In the bearing selection, you must compensate. Table 1&#0; 7 provides several bearing type allows different axis. If you do not exceed the allowable value, this does not need to be modified. Table 1&#0; 7 allowed (asexual can worsen) different axis Although each type of bearing a correction coefficient of a basic set of different axis, but manufacturers design their characteristics also plays an important role, you must consider these characteristics. Usually, manufacturers of the sample list their products of these coefficients. Shape constraints The rated load requirements once the final value, you must consider to install the required bearing dimensions, installation and fixation of the considered here include bearing. And with the bearings required rated load matching shaft size. These factors help to determine the bearing structure and size, can also exclude some bearing type. In some cases, because of space limitations even before the rated load to determine the exclusion of choice. For example, if the bearing is very narrow, ball bearing is the only type can be on the job. Or, if you need to use the bearing box of very small diameter, you need two or more roller bearing can be installed on the same shaft reaches the rated load enough. Bearing load size and requirements when the measure has the very big difference, there is another common contradiction. If the shaft and load is light, even if the rated load requirements are very small, but also put forward an expensive, large bearing with high load, in this case, the best contact with the bearing manufacturers, in order to make one of the most economical and effective solution. Example The basic working conditions. If bearings used in the reducer, bearing must be supported by one end diameter of about 25mm axis, and the installation of a spur gear shaft. The work cycle and bearing load. Working cycle analysis and transmission gear force that: radial load bearing about the bear in the 3/4 time is 1780N, speed of 11000r/min, in the 1/4 run time, radial load bearing 890N, speed of 3500r/min. Is meshed well almost no axial force, there is no cable mesh or other effective axial force. Expected maximum axial force of two direction is 89N, the maximum vibration force is 89N. Size limit. Because of the reducer internal design constraints, the largest diameter allows the bearing is 70mm, the maximum calculated scrambling degree is 6, the maximum position different axial degree is 0, 0015. Don't ask for self-aligning bearing. Environmental Science. Bearing lubrication and lubrication as engagement: from a large oil tank of fuel injection, the highest expected temperature is 140 F. Reliability. The bearings should be continuous work must have a good reliability, the reliability failure rate of 8%. Selection steps 1 bearing inner diameter of about 25mm. 2 bearing outside diameter is 70mm. 3 estimation of maximum diameter of D (the average value of the bearing inner diameter and outer diameter) for: (25+70) /2=47.5 (mm) The calculation of the maximum DN value of 4: 47.5 x 11000=0, 52 x 106 The basic bearing type 5 for selecting the required, determine the correction value of DN. First of all, the type of lubrication to find correction bearing limit speed coefficient. From figure 1&#0; 2 check, the small oil groove continuous work, coefficient of 0.85. Oil tank. The intermittent work, coefficient of 0, 95, low value and continuous work, modify the DN value: 1.52 × 10?) /0, 85=0, 61 × 106 1 using the step 5 to obtain the value of DN and 1&#0; 2 of the results, we find that the angular contact ball bearings and industrial grade, precision cylindrical roller bearings, deep groove ball bearing and range of speed (speed limit) is equal to or greater than the modified DN value, therefore, these are the first choice of the bearing type. 2 by the equation (D) to calculate the equivalent load: 3 determine the reducer working life basic. From the expression of 1&#0; 4, typical working life of ordinary gear reducer 20000h. 4 with the given reliability failure rate correction work life. The expression of 1&#0; 5, 8% reliability failure rate gives life correction coefficient is 85%; hence correction work life L: 20000/0. 85=23529 (H) 10, using equation (E) computing needs of the dynamic load rating C 11, using the vibration to correct C. in this example, the minimum stable load 890N is greater than the maximum vibration load 89N, vibration and stability of the load ratio is 0.1, using table 1 - 6, using linear interpolation between two load closest rate into a correction coefficient, such as the coefficient calculation: (1.00+1.020) /2=1.010 Modify the rated load value: C=1.010 * 29746 (N) 12, according to the different axis flexure degree and the position of different axial degree, determine whether to modifying C. Table 1 - 1 indicated that the two kinds of different degrees of shaft expected values were in the range of values without compensation, so there is no need to modify. If two different axial degree or one of the expected value than the scope of compensation, it must consult the bearing manufacturer documentation to determine the compensation. 13, find the bearing type required. Table 1 - 8 shows that from this table can be found in required for bearings. The bearing of any type, rated dynamic load C value must be equal to or higher than the above mentioned our final correction value 29746N Table In fact, you may be familiar with to easily determine the price and size can meet the requirements of each type of bearing in the table, in your choice may consider the price factor, here we assume: in Table 1 - 8 bearing marked "carrying capacity" of the most expensive, therefore, should be eliminated. The best choice is the inner diameter of industrial grade cylindrical roller bearing 30mm, now focus on the types of the basic bearing, to continue the selection process. 14, determine the bearing is positioned or non location type. Because the bearing must be subjected to axial loads in two directions, so at one end of the shaft is a bidirectional locating bearing. 15, selection of bearing tolerance grade. The speed reducer does not need high accuracy, so using PO. 16, check to see whether the thermal environment of special. Because the expected maximum working temperature is 140 ° F, therefore does not need the special material. Thus, clearance for the 0 set of values. Check the DN and the speed limit: Dm6x = (30+62) /2=46 (mm) The highest speed requirements do evil all kinds of evils is given by the 11000r/min DN value is 506000, slightly lower than the calculated in step 4 of the DN value, also in Figure 1 - 2 shows industrial grade cylindrical roller bearing DN value range. The bearing from the directory can be seen, this bearing limit rotational speed is 16000r/min, far above the maximum speed of 11000r/min, therefore, does not need to consider the thermal environment of special. 17, consider the coaxiality requirements. There is no special coaxiality requirements, therefore, the use of standard bearings can be, but in the manufacturing tolerances to ensure the coaxial bearing degree. 18, considering the requirements of installation, easy to install. With production personnel to show that, the best way for them is only the inner ring is mounted on the shaft, outer ring and the roller arranged on the speed reducer is installed in the process, and then with the movable positioning part is arranged together. This led to the second structure selection, from Figure 1 - 3 bidirectional positioning option second positioning structure, movable positioning part by the nut and lock washer is fixed on the inner ring. Because of the bearing may be easily removed, so the structure is convenient for replacing. Repair personnel only need a removing device can be demolition of inner ring. 19, the overall selection. Bearing final is to meet the minimum requirements of bearing most economy, it is the industrial grade cylindrical roller bearings, inner diameter 30mm, diameter 62mm, width of 16mm, the positioning structure with a movable positioning part on the inner ring, 0 groups of clearance, the tolerance grade for class ISOPO. In recent years the Swedish SKF company has put forward the new theory of the bearing life, bearing size selection method by using this theory. Have been included in the publication of the bearing in the sample. 1 rolling bearing replacement 1 the substitution principle Rolling bearings have such a feature: the inner diameter of bearings of the same type at the same time, along with the increasing diameter of series, and its diameter and width increases, the bearing rated dynamic load load and rating will improve with the same dimensions; diameter, with the increase of the diameter series, but with smaller diameter, width increase accordingly, bearing dynamic load rating and overdetermined static load increases. For the same diameter, outer diameter and width can be found bearing a variety of different; while the same diameter, and can find multiple internal diameter and the width of the bearing. For the same inside and outside also can find bearing different width, which laid the foundation for the substitute of the rolling bearing, provides a convenient. According to rolling bearing the size characteristics and application practice, selection of alternative bearing, should follow the following principles: 1 according to the bearing data found ratings and the original use bearing dynamic load rating C static load C0 value, and according to the comparison of calculation the bearing life calculation formula to calculate life original bearing and prepare alternative bearing and bearing capacity. It must be pointed out that, the rated service life and bearing dynamic load C value of 3 (ball bearing) or 10/3 (roller bearings) will increase, but the dynamic load rating of C value is not the only standard to measure the service life of the bearing, such as found in the alternate bearing dynamic load rating C hours than the original use of the bearing, it should consider increasing the bearing of other technical characteristics and host repair times and economic cost, the actual service life or from the lubrication angle and effective measures to prolong bearing, in order to meet the alternative rationality. The speed limit bearing 2 substitution per minute allowed should be equal to or the actual speed is higher than that of the original bearing in mechanical equipment. Because of the higher speed, the centrifugal force of the rolling is big, this will not only increase the bearing load, but also make the unit time bearing number increase, easy to produce the material fatigue, reduce bearing life, so choose HISTEP speed limit bearing some alternative. 3 alternative bearing size should be the same with the original bearing size, size can not be changed and the outer ring of the bearing housing hole matched, or with the bearing inner ring of the shaft neck size, in order to buy the original bearing, re install the original bearing. 4 alternative bearing clearance to clearance and the bearing agreement. Tolerance grade 5 alternative bearing should be equal to or higher than the original bearing after installation, avoid the precision machinery and equipment affected. 6 using the insert method for bearing substitution, to ensure that the sleeve outer cylinder, and the coaxial degree, and should be in processing by selecting correct tolerance. To replace the imported bearings to domestic bearings, we must first understand the foreign bearing code, manufacturer and bearing the technical characteristics from the actual equipment data or the original equipment, then alternative work, and pay attention to: ? according to the basic code foreign bearing used in the original equipment dimensions, specifications, types and manufacturers from home and abroad, bearing type control to find out the corresponding alternative bearing the manual basic series and code, and check the installation size bearing, especially the double row, four row tapered roller bearings and tapered roller (single) bearing, angular contact ball bearings are assembled width after assembly (or height) and bearing the actual use are the same. To understand the technical characteristics of the bearing?. Technical characteristics of the bearing is generally used in the bearing code pre - or post code, and the code representation method and technical implications of the corresponding bearing factory is not the same, but no matter what a bearing factory, because of a bearing only one code, and a bearing the basic code. The code can only express a technical characteristics, so a certain period clear name bearing factory or company in domestic bearing replacement, then from the relevant technical meaning to find the information bearing symbols of pre - and post code, the solution of the original bearing structure or technological characteristics. No information available? In the case, experts can manufacturing plant by the domestic bearing determine alternative scheme, or according to the main technical parameters to determine the bearings imported bearing in surveying and mapping to the trial manufacture of new products, and its performance is compared with the trial or and foreign bearings gradually substitute. Selection and alternate bearing is a very detailed technical work, should accomplish as far as possible with the manufacture of bearings and bearing of the user design, especially in the selection and development of new structural bearing and replace bearing major equipment in the domestic use of bearings should be so. 1 alternative methods 1 direct substitution When the selected alternative bearing, regardless of is the same type or non - the same type, as long as the inner, outer diameter and width dimensions and technical performance of the same, without any modification and processing, can be installed to substitute. For example, Dongfanghong 40 tractor in NJ306 (original code 42306) bearing, 30mm inner diameter, outer diameter is 72mm, width is 19mm, can be directly used NF306 (original code 12306), 6306 (original code 306) bearing substitution. 2 plus pad alternative When the selected alternative bearing inner diameter, outer diameter and the first bearing and the bearing substitution of the width difference. Pad diameter and shaft neck with loose fit, outer diameter is equivalent to the bearing inner diameter, and the two end surface should be parallel. When installing, mats on the shaft shoulder mounted, installed outside the bearing substitution. For example, Dongfeng 32209 tractor in 50 (original code 7509) bearing, inner diameter 45mm, diameter 85mm, width of 24. 75mm. When the 30209 (original code 7209) bearing substitution, the inner diameter, the same, but the width is narrow, 20. 75mm, just add a 4mm thick pad can substitute. Figure 1 - 4. The 3 generation of narrow to wide substitute When the bearing can't find alternative bearing size similar, while the axial position is not restricted, can be used instead of a narrow wide bearing bearing. For example, the use of the axle on the walking tractor 30207 (original code 7207) and 30205 (original code 7205) bearing, used 32207 (original code 7507) and 32205 (original code 7505) bearing substitution. The 32207 and the 30207 bearing, the identical diameter, and width of 6mm; 32205 and 30205 bearings, the identical diameter, and the width of 3mm, the shaft end is threaded locking nut, can adjust bearing clearance and locks. 32207, 32205 bearing the rating dynamic load and static load rating C C. Than the original bearing, substitution will make its work life increased. 4 inner bushing replacement When the selected alternative bearing width, the outer diameter is equal to the original bearing, the bearing diameter greater than the original, the inner bushing, as shown in Figure 1 - 5. The diameter is directly matched with a shaft, the requirement of tolerance and technology with the same size and diameter of bearing. Set of outer diameter is directly matched with alternative bearing inner diameter, the property should use the basic hole system transition fits slightly tight. The material selection of 45 steel manufacturing, generally do not need heat treatment can be used. 5 outer bushing replacement When the selected alternative bearing diameter, width is equal to the original bearing outside diameter less than the original bearing, the outer bushing. Set of outer diameter is directly matched with a shell hole, the requirement of tolerance and technology with the same size and bearing outside diameter. The diameter and the outer diameter of the bearing substitution set the basic shaft system transition fits slightly tight. 6 diameter or diameter insert pad alternative When the inner diameter and the original alternative bearing the same, and the outer diameter, width is smaller than the original bearing, the outer sleeve and padded substitute. Pad shall be added to the shaft shoulder, as shown in Figure 1 - 6. If the alternate bearing inner diameter, width is small, the diameter of bushing and pad. 7 inner diameter and outer diameter greater than the original bearing, and the outer diameter of less than the original bearing, adopting inner, outer diameter and insert substitution. This method used for the alternative non-standard bearings and larger bearings, the general should not be used, because it requires the processing size of two sets, the processing time and material costs. 8 two sets of bearing substitution of a bearing When the selected alternative bearing diameter is equal to or greater than the original bearing inside diameter, and the outer diameter of equal to or less than the original bearing outside diameter, width is equal to or less than the original bearing width 1/2, can use two sets of bearings instead of a set of bearings. This method can improve the bearing capacity and service life of the bearing substitution. For example, NU2312 Tieniu 55 tractor (original code 32612) bearing, the size is 60 * 130 * 46 (mm), can use the same type of NU212 (original code 32212) two sets of bearing replacement. NU212 bearing size 60 x 110 x 22 (mm), substitution, diameter of bushing, and the cushion can be 2mm wide shoulder. Alternative, its working life and the original bearing is basically the same. Bearing restructuring alternative? When the bearings are of the same type, not only structure at the same time, the bearing can be reformed alternative. Such as 6409N (original code 50409) bearing, 6409 (original code 409) bearing on the outer circle cut stop groove substitute, the same size. The restructuring of the bearing, high hardness, HRC61 - 64, therefore, generally used in the YT30, YW1, YW2 alloy knife, in the lathe speed small feed, plus emulsion cutting system. Changing the size of the shaft or housing holes? When the bearing inner diameter slightly smaller than the original bearing inner diameter, outer diameter slightly larger than the original bearing outside diameter, can adopt the alternative. The shaft of the small car, processing to tie with the alternative bearing diameter phase size, or the shell hole boring, processing to cooperate with alternate bearing outside diameter size of. It is worth noting here is, processing volume shaft or shell hole should not be too large, so as not to affect the strength of the parts. This method applies only to non standard bearing on individual has been eliminated and will not buy the original bearing, is generally not used. Substitute of imported bearings? With the deepening of reform and opening-up, the implementation of a market economy, the GATT contracting party status recovery, China's exchanges with other countries more and more frequently, electromechanical equipment abroad will influx China market. When these electromechanical equipment needs repair, foreign bearing the original installed on the device to be disassembled and replaced, foreign bearings imported temporarily and not buy, or based on economic considerations, have domestic bearing replacement. There are two alternative methods of imported bearings: a look at home and abroad bearing model control manual, take the same type of alternative; two is the way to domestic bearing code, find the corresponding domestic bearing alternative, namely first determine the bearing type, structure features, technical performance, and then measure the inner, outer diameter and width dimensions, on the basis of measurement data, find the rolling bearing product samples, determining the bearing model to substitute. Fit tolerance 1 insert substitution at When the rolling bearings with outer diameter insert method to substitute, because the set of outer diameter is directly matched with a shell hole, the outer diameter of the same original manufacturing tolerances and the diameter of the bearing, and the diameter and the outer diameter of the bearing substitution set the basic shaft system transition fits slightly tight. The diameter tolerances set by delta Dmp bearing outside diameter selection, diameter tolerances set according to GB1801 - 79 selection. When the rolling bearings with inner diameter of insert method to substitute, because the sleeve diameter directly with the shaft, the inner diameter of the same original manufacturing tolerances and the inner diameter of bearings, and the outer diameter of the inner diameter of the bearing sleeve and substitute the basic hole system transition fits slightly tight. Delta DMP diameter tolerances set by the original bearing bore diameter tolerance selection, sleeve, with reference to GB1801 - 79 selection. In addition, in the selection of fit tolerance, should pay attention to: 1 bearing hole and the base hole hole the limit deviations in different directions; 2 rolling bearing outside diameter and shaft basis system of the shaft of the limit deviation direction are the same, but the values are non complete correspondence. So in determining the substitute part of inner, outer diameter, according to the requirements of fit tolerance level and bearing, after calculation, select appropriate limit deviation. 1 bearing alternative general rules Substitution of rolling bearing, is generally the first to select alternate bearing from lower than the original bearing the diameter diameter in the series, and alternative bearing selection and its diameter should be the same as the original diameter is larger than that of the original bearing, bearing. This is mainly on account of: (1) the processing is convenient, save material; (2) alternative, higher rated load bearing, life is not affected. 1 deep groove ball bearing replacement rule 6400 - 6300, 6200 alternative. 6300 - 6200, 6100 alternative. 6200 - 6000 alternative. 60000 - 2Z - 6000 - Z substitute. For example, type 60000N belongs to the outer ring of deep groove ball bearings with snap groove, selection of alternative bearing, the 6408N (original code 50408) bearings can choose 6310 (original code 50310) diameter insert substitute, also can choose 6408 (original code 408) slot cut in outer diameter end of alternative. 6310 (original code 310) bearings can choose 6212 (original code 212), 6210 (original code 210) bearing inner sleeve and pad alternative. 2 tapered roller bearing substitution rule 32300 - 32200, 30300 alternative 32200 - 30200 alternative 30300 - 32200, 30200 alternative 30200 - 32000 alternative For example, 32308 (original code 7608) bearing, optional 32210 (original code 7510) diameter insert pad substitute; also the optional 32208 (original code 7508) diameter insert pad alternative. Also optional 30308 (original code 7308) plus pad alternative. Tapered roller bearings are often used in pairs, the installation has the clearance adjusting mechanism (with nuts or increase or decrease shim adjustment in general), selection of alternative bearing, the bearing width than the original bearing a slightly thinner or thicker, can no longer add washer, the only difference is larger, was placed on the axial. (3) cylindrical roller bearing substitution rule N2300 - N2200, N300, N200 substitution N2200 N200, N1000 substitution N400 N300, N2200 substitution N300 N2200, N200 substitution N200 N1000 alternative In addition, cylindrical roller bearings and NU0000 (original code 32000), NJ0000 (original code 42000), the two types of N0000 (original code 20000) diameter series bearing the same, so the alternative rules and the same N0000 type. At the same time, N0000 type, NU0000 type, NJ0000 type, NF0000 type also can substitute. For example, NU23, 12 (original code 32612) bearing, by N2312 (original code 2612) bearing substitution, the same size, do not need to be processed. Alternative patterns of the 1 angular contact ball bearings Angular contact ball bearings with contact angle size, a to 15 ° 7000C (original code 3600), a (25 ° 7000AC original code 46000), a (40 ° 7000B original code 66000) type three kinds, each type has a deep groove ball bearing as diameter series. In addition to substitute in the types of diameter series inside and outside, still can substitute each other, and more to bearing contact angle angle substitute small. The alternative rules for: 7400C - 7300C, 7200C, 7400AC, 7300AC, 7200AC substitution 7300C - 7200C, 7000C, 7300AC, 7200AC, 7000AC substitution 7200C - 7000C, 7200AC, 7000AC substitution For example, 7307C (original code 36307) bearing, available 7208C (original code 36208) bearing inner sleeve and pad substitute; can also be used 7307AC (original code 46307) bearing substitution, the shape of the same size, do not need to be processed. 1 different types of bearing each alternative rule According to the structure and size of rolling bearing analysis comparison, most of the rolling bearing in the bearing designation, right three digits of the same, the inner, outer diameter is identical (except the needle roller bearing, thrust ball bearing and non-standard bearing), such as 6308 (original code 308) bearing and N308 (original code 2308), NU308 (original code 32308), NJ308 (original code 42308), 6308N (original code 50308), 6308 Z (original code 60308), 1308 (original code 1308), 7308C (original code 36308), 7308AC (original code 46308) dimensions such as bearing, is 40 * 90 * 23 (mm), the same size. Therefore, in the selection of alternative bearing, when the same type of bearing is not found, can be widely to choose other types of bearing replacement. Usually: Cylindrical roller bearing and deep groove ball bearing interchanged, secondly available self-aligning ball bearings or spherical roller bearing substitution. Tapered roller bearings, angular contact ball bearing and deep groove ball bearing interchanged. Spherical roller bearings and self-aligning ball bearing interchanged. The second chapter rolling bearing installation Repair of 1 shaft and housing bore Rolling bearings prior to installation, should conduct a rigorous testing of matched with the shaft hole, casing, end cover and other components; the shaft, hole used, should be more comprehensive testing of the accuracy, non-conforming parts should be repaired or replaced. Otherwise, do not allow the assembly. Repair of 1 axis Eccentric 1 inspection shaft neck, bending and diameter variation (Tuo Yuandu) The shaft at the top of the top two on the lathe, or placed with cast iron plate of V type bearing, shaft neck with a dial indicator pointer contact with the bearing, and then slowly rotating shaft, observation indicator pointer in the shaft neck swing. If the shaft rotates a circle, a pointer in a swing, and then back to the original position, the shaft with an eccentric or bending, eccentric, the bending amount for half the dial pointer swing value; if the shaft rotates a circle, the dial pointer swing two times, and back to the original position, the shaft neck ellipse the dial indicator pointer, the maximum and minimum values of the index of the difference is the ellipticity values. When the shaft eccentricity and bending degree is larger than a predetermined value, deal with the shaft alignment or turning and grinding. Ellipticity values generally should not exceed the shaft neck size tolerance of 1/2, is too large should be welded, cars, grinding, repair. 2 inspection shaft neck surface roughness Journal of burr, touch marks, should be used carefully filed away, and then fine emery cloth polishing. Fillet radius shaft verticality and shoulder root 3 inspection shaft neck Vertical shaft shoulder by right angle size close to the shoulder, so close together, and then by the light or sunshine inspection, such as leaky uniformly or non leakage, the vertical shaft shoulder. Fillet Radius Fillet samples available inspection shaft shoulder root. The radius is too large, bearing and shaft shoulder is not tight, easy to cause vibration in use; the radius is too small, will affect the strength of shaft. Therefore, the radius of fillet radius shaft shoulder root must be less than the inner ring of the bearing, the general should be the bearing inner ring radius 1/2, in order to ensure the bearing to the shaft shoulder. 4 inspection shaft neck size Available micrometer or dial test. When the shaft neck wear, size is less than the specified with the requirements, and the inner diameter of the bearing with loose, deal with the bearing neck repair. There are four general repair method: 1 insert the journal over the thick (greater than 40mm), the first shaft neck turning off 10 - 15mm, then heated in a heat engine oil formulated put good set, will suit to the shaft neck car fine with hot charging method, finally finishing bushing diameter, the size of with the inner diameter of the bearing requirements. 2 welding grant first shaft neck coarse grinding a knife, cutting off 0. 3 0. 5mm, and then the gas welding or welding repair welding, after welding, the machine will shaft grinding to the required size. Bending deformation for the prevention of welding time axis, can reverse the deformation of symmetrical balance type compound welding method welding. 3 chrome plating and electroplating be just and stern shaft neck size wear lighter, or processed ruler over difference, this method can be used to first plating after grinding, repair. The 4 knurled Chong see things in a blur when the journal size slight wear or processing slightly when the ultra poor, available punching shaft neck circumference to play some small holes on the small holes, edge convex super section increases the shaft neck size, or in the lathe with knurling cutter align the shaft neck knurling, increase the shaft size, cooperating with a bearing installation. This method can only be used as temporary emergency measures, the general should not be used. Repair of 1 hole Elliptic and cylindrical 1 inspection hole (taper) The integrated shell hole, check inside micrometer or vernier caliper; on the open shell hole, must be the upper and lower two parts together, screwed, to be joined to inspection. Verticality shoulder 2 inspection hole and shaft The shaft shoulder and the rotary center line is not vertical, the load is easy to concentrate in the bearing rolling body part, the stress is not uniform, creeping, and make the roller pressure is too large, leading to deformation, affect the life of. The available light gap method with square close to the shaft shoulder test, also can use the dial pointer measuring shaft shoulder face runout check. 3 inspection hole wear and coaxial degree The shell of bearing hole deformation due to wear or boring machining error, often can appear not concentric holes at both ends. If not concentric, after installation can make the gear axis axis tilt, damage to the drive gear and the driven gear center distance, damaged parts, the death card bearing bending crack of bearing shell hole. The bearing shell hole coaxial degree should be strict test. After the test, the wear volume when the bearing shell hole is larger than 0.1mm, or two bearing shell hole axiality is greater than 0.7mm, can be used to insert method to repair. Firstly the shell hole boring, pressed into the Bush, and along the seams round drill three holes are distributed equally on Wednesday 2 3mm deep, and then pile welding solid boring flat in the blind hole, size the inner hole boring and the embedded bushing is matched with the outer diameter to bearing. When the hole wear and coaxial degree is small, the available bonding repair. The polyamide resin, 50% of the 50% "6101" of epoxy resin and iron powder, or used for agricultural machinery, 1 No. 2 glue and iron powder, bond in the bearing shell hole, after curing boring to the required size. Preparation before installation? Selection and requirements of installation site 1 The installation site should be a distance with the lathe, grinding machine and other mechanical equipment. The site should be clean, keep clean and dry, to prevent iron, sand, dust, moisture into the bearing. 2 inspection of bearing type, prepare installation tool Inspection of bearing type, size meets the installation requirements, and according to the structure characteristics of bearing and the various components, select the appropriate assembly method, you are ready to install the tool and gauge. Installation tool used a hammer, copper rod, sleeve, special plate, screw mosquito clamp, press, with vernier caliper, micrometer, dial indicator, etc.. 3 test the surface of bearing assembly The surface of bearing assembly and tie in to the part surface, such as scratches, rust layer, debris, sand, dust and soil, a bearing installation difficulties, resulting in incorrect assembly position; the two is the attachment formation of abrasive, easy to wear, bearing surface, affecting the quality of assembly. Therefore, with the surface before installation with shaft, bearing shell hole surface, face, shoulder and connecting parts such as Bush, washer, end, careful inspection. If there is corrosion layer, usable fine rasp rasp, sand cloth illuminated, but also to remove the surface of bearing assembly and attachment of the connected parts. Bearing cleaning 1 bearing cleaning Bearing the above new, the vast majority are coated with grease. The oil is mainly used to prevent the bearing does not rust, lubrication, therefore, must be thoroughly cleaned before installation. Cleaning method is: where the antirust oil seal bearing, use gasoline or kerosene wash. Where the use of thick oil and rust preventive oils such as bearing Vaseline antirust for industrial use, can use first No. 10 oil or heating transformer oil dissolved cleaning (oil temperature should not exceed 100 ℃), the bearing oil immersion. One, to be antirust oil dissolved out after cooling, cleaning with gasoline or kerosene. Bearing where vapor agent, antirust water and other water soluble antirust materials and rust, usable soap base other cleaning agent, such as 664, 6503, 6501, peregal, cleaning agent. Use gasoline or kerosene to clean, should one hand knead bearing inner ring, the other hand slowly turn the outer ring, until after a rolling body of the bearing, roller, keep the oil shelf completely washed off the surface, then clean the bearing outer ring. It should also be noted when cleaning, began to slowly rotating, reciprocating shaking, not too much force rotation, otherwise, the dirt damage bearing raceway and rolling body is easy to be attached. Bearing cleaning quantity is larger, in order to save gasoline, kerosene and ensure the cleaning quality, can be divided into coarse, fine cleaning in two steps. For bearings with inconvenient to remove, wash oil available to tears. The temperature of 90 ° --100 ℃ hot oil poured hot, the old oil dissolved, with hook or a small spoon to dig out the old oil bearing, and the remains of the old oil, kerosene oil inside the bearing rinse, wash again can last gasoline. The cleaning quality of the bearing by hand test. Carefully observe the bearing after cleaning,, on the inner and outer ring raceway, the rolling body and a retainer gap there will always be some residual oil. Inspection, can be used to clean the feeler gauge inclined remaining oil scraping, apply to the thumb, index finger back and forth slowly rubbing grinding, fingers if a rustling sound, the bearing is not clean, should wash them again. Finally, bearing in his hand, pinch the inner ring, outer ring (a horizontal rotating large bearings can be placed in the assembly stage, the inner pad, the outer ring is pressed, inner circle, rotating outer ring), with flexible rotation, no block, no bounce pass. The bearing cleaning good, filled with lubricant, should be placed in the assembly stage, the following mat with net cloth or paper pad, for assembly covered with plastic sheeting,, are not allowed on the ground or on the box. Mobile bearing, not allowed to directly with the hand, should Dafanb gloves or use net cloth bearing package and then take, otherwise, with sweat, moisture hands after contact, easy to produce rust bearing fingerprint. The bearing with two shields or seals, as well as bearing coated with antirust, lubrication and oil, because at the time of manufacture have been injected into the grease, so don't clean before installation, for example, 51708ZHS and 12, Hong Wei - 12 type tractor and Dongfanghong 20 tractor clutch (original code 688808) bearing. Cleaning the 2 shaft and the bearing shell hole and other parts With gasoline or kerosene to clean, dry cloth to wipe, and then coated with a small amount of oil in order to facilitate the installation. These parts after cleaning, attention should be paid to every casting with sand to completely remove all burrs; sharp and bearing parts must be removed, lest, residual sand and metal fragments in the installation into the bearing assembly quality, effect. 1 note The inner, outer ring can be separated bearing outer ring of mutual exchange, don't mistake so as not to affect the quality of contact. On the ball and spherical roller bearings, must not be arbitrary to rolling element bearing Lu out mix, so as not to affect the accuracy of the installation position. When mounting bearings, to facilitate the inspection bearing code, not an error, the bearing ring side arrangement and installation type. The heating shell hole 2 bearing and the bearing seat For a large amount of surplus, large bearing, in order to facilitate the installation, must be installed before heating; for light metal bearing shell hole tight fitting (such as aluminum bearing seat), due to very low surface hardness, to prevent the bearing outer ring is pressed into a bearing shell hole is scratched, napping, should also be heating installation. Heating method, usually bearing or the separation bearing ferrule, placed in clean the oil tank, the oil flooded bearing, uniform heating. The temperature reached 80 - 90 ℃, remove wipe, while hot installation. The tank can be made of 2 - 3mm thick iron plate, from the bottom of 50 - 70mm high with a porous plate, bearing is arranged on the porous plate heating. Its purpose is to avoid the precipitation of impurities in the oil into the bearing. However, for the bearing surfaces with shields or seals, because in the manufacturing of lubricants have been added, the pre - installation can not be heated. 1 rolling bearings with 1 selection basis According to the rotation loads acting on the bearings relative to the ring, the load bearing ring bearing has three kinds: local load, cyclic load, oscillating load. Usually cyclic loading (axial rotation), oscillating load the tight fit; local load in addition to the special requirements for general use, a tight fit. When the bearing under dynamic load and the heavy load, inner, outer ring shall be used for interference fit, but sometimes the outer ring can be a little looser, should be able to make axial swimming in the bearing shell hole; when the bearing ring subjected to oscillating load and load is light, can be used to mix with a little loose tight some of the. (2) load The amount of interference is determined between the bearing and shaft or housing bore on the load size, load is heavy, the larger the amount of interference fit; load is light, the relatively small interference volume with. The general radial load P is less than 0. 07C at light loads, P greater than 0. 07C and less than or equal to 0. 15C for the normal load, P greater than 0. When 15C (C for heavy load bearing dynamic load rating). The working temperature? Bearing in operation, the ferrule temperature is often higher than the adjacent parts of the temperature, therefore, the inner ring of the bearing may be due to thermal expansion and the shaft from loosening, outer ring may be due to thermal expansion effect of bearing in the housing bore axially moving. Help select, the bearing device part temperature difference, swelling shrinkage should be taken into consideration, large temperature difference, selection of shaft matched with the inner ring of the surplus capacity should be greater. Rotary accuracy? The bearing rotation accuracy requirements, in order to eliminate the influence of the elastic deformation and vibration, should avoid the clearance fit. ? structure and material bearing housing hole On the form of shell holes, and the outer ring of the bearing is matched with an interference fit, should not make the outer ring to rotate in a shell hole. When installed in a shell hole, light metal shell hole or hollow shaft bearing, with the thick wall shell hole, cast iron shell holes or solid shaft closer. Convenient installation and disassembly? For heavy machinery, bearing should adopt the loose fit. The tight fit, can choose the separation type bearings, inner ring with cone and set with tight or unloading sleeve bearing. The axial displacement of the bearing? Fit, when a ring for bearing in operation can move in the axial direction, the outer ring of the bearing and the bearing shell hole should adopt a loose fit. 1 coordination selection With the bearing and the shaft with hole base, and cooperates with the housing is a basic shaft system. The machine manufacturing industry with the bearing and the shaft of the tolerance and fit system is different, the bearing inner diameter tolerance zone is in change, therefore, the same with the condition, with the inner diameter of the bearing and shaft fit more closely than usual. Bearing outside diameter tolerance zone and shaft basis system the central axis of the tolerance zone although the same is below the zero line, but its value and the general tolerance system is not the same. All kinds of bearing in the installation, selection of shaft and housing bore tolerance zone is shown in Table 2 - 1~2 - 4. Different tolerance levels of bearing and shaft and housing tolerances, see GB275 - 84, or bearing samples. 1 rolling bearing mounting points 1 installation methods 1 using copper and manual hammering installation This is a simple way to install in small bearings. When the inner ring of the bearing outer ring is tightly matched, is a loose fit, the copper rod close to the end surface of the inner ring, direct percussion hammer copper and copper, by force, will be fitted to the shaft bearing slowly. The inner ring of the bearing is large, available copper along the bearing inner ring face evenly around the hard hit, not only on the side, also cannot too hard to beat, symmetry, gently tapping slowly mounted, to avoid loading the inclined crack of bearing. When the outer ring of the bearing inner ring is tightly matched, is a loose fit, can be used with the method of the opposite, with hammer percussion copper bar close to the bearing outer ring face, the bearing is pressed into the bearing seat, finally fitted to the shaft, which is not easy to damage parts. 2 use the sleeve installation The method and installation of the same truth by copper bearing. It is the direct pressure on the bearing sleeve on the end (bearing installed in the shaft on the end face of the inner ring is arranged in the housing hole; when the pressure gauge 6 outer end face), with hammer percussion force can be evenly distributed in the installation of the bearing of the ferrule end face, and can be used in conjunction with the press, the installation of labor-saving and time-saving, reliable quality. Sleeve installation should be made for the soft metal (copper or low carbon steel pipe can be). If the bearing is mounted on the shaft, the inner diameter of the sleeve should be slightly larger than the shaft neck 1 4mm, slightly smaller than the outer diameter of bearing inner ring rib diameter, or taking the sleeve thickness as the standard, the thickness should be made equal to the bearing inner ring thickness of 2/3 - 4/5, and the two ends of the sleeve should be flat and cylinder body vertical. If the bearing is installed in the seat hole, the sleeve diameter should be slightly smaller than the outer diameter of the bearing. Install the bearing sleeve, such as component is small, can be placed in a vise mounted. Jaw pad with aluminium or copper sheet, to prevent axial pinch. If the product is large in size, should be installed on the gallows. The bearing on the shaft, then install the sleeve, hammer tap evenly slowly assembly sleeve. When the sleeve end cover is a flat topped, hammer should be along the circumference are evenly percussion set. Table 2 - 1 shaft tolerance installation radial bearing and angular contact bearing belt Note: any occasions with higher requirements for tolerance, J5, k5...... Instead of J6, k6...... Etc.. The single row tapered roller bearings and double row angular contact ball bearing, due to the impact of internal clearance is not very important, can use K6 and M6 instead of K5 and m5. The radial clearance of bearing roller bearing selection should be larger than the fundamental group. The van had higher tolerance level or speed, should choose H7, IT5 as the shaft neck shape tolerances. Size greater than 500mm, the shape of the tolerance to IT7. Table 2 - 2 shaft tolerance installed thrust bearing with Table 2 - 3 the housing bore tolerances installation radial bearing and angular contact bearing belt Table 2 - 4 the installation shell hole tolerance of thrust bearing with Cylinder on both sides, when the sleeve cover is spherical, at the center of percussion hammer should be spherical end cover. If the bearing inner, outer ring and the shaft and the bearing seat hole is a tight fit, one end of the end sleeve made of double loop, or with a single ring sleeve with a disc mounted bearings, as shown in Figure 2 - 1, 2 - 2. When installed, the ring sleeve or disc close to the bearing, the outer end face, press pressure hammer, the bearing to the shaft and bearing seat hole. This can be avoided when installing cage damage. This installation method is only suitable for the installation of retainer bearing not protruding ferrule end face. 1 use the press mounting This method is used together with the sleeve installation, can be hand hammer pressure bag. The bearings are not struck, and parts of bearing matched sealing devices are not damaged. The press mounting bearings, should make the press machine rod and the central line of the sleeve and the bearing coincides with the central line, the pressure is located in the center, in order to prevent the installation deflection fracturing bearing. The 2 heating installation For the installation of bearing interference larger or large size bearings, in order to facilitate the installation, can use the principle of heat expansion and cold contraction, the bearing heating with copper, sleeve and a hammer to install. Heating methods such as the second section of this chapter is about the housing bore heating of bearing and the bearing seat said, in general the temperature below 100 ℃, 80 ℃ - 90 ℃ appropriate. When the temperature is too high, easy to cause the bearing ring raceway and rolling body annealing effect, hardness and wear resistance, resulting in bearing life reduces and scrapped prematurely. Install bearing using the heating method, the oil temperature to reach the required temperature after 10 minutes, should be promptly removed from the oil in the bearings, while it is hot in the shaft. When necessary, can be installed in bearing inner ring end face with a bit of pressure, it is easier to install. Bearing in the shaft, must immediately pressed until the inner ring, cooling. At present, some foreign companies have developed a variety of bearing used in the installation of the bearing heating bearing devices, such as electric induction heater etc.. 1 different types of bearing installation Deep groove ball bearing installation Specifications of deep groove ball bearing, large quantity, wide application. The installation method is relatively simple, should consider the coordination selection. A matching with the inner ring and the shaft neck can be calculated the amount of interference: ? Type in Between the delta d inner diameter of the bearing and shaft neck and the amount of interference (m) D - bearing inner diameter (mm) B - bearing width (mm) R - bearing radial load (N) Between surrounding Δ T bearing inner and shell temperature difference, generally 5 - 10 After calculation, according to the amount of interference calculation, determining the nature and shaft, and the shaft is machined to the required size of installation. 1 full needle bearing installation Install full complement needle roller bearings, usually carried out using an auxiliary sleeve. The auxiliary roller, the auxiliary sleeve diameter should be better than the shaft diameter of 0 small. 1 0. 3mm. When installing the bearing outer ring, inner surface coated with grease, by placed within the surface mount needle (put the last needle should be gaps), and then to replace the shaft or bearing inner ring of the auxiliary roller or auxiliary sleeve into the outer hole, and the end surface mounting shaft or bearing alignment the end face of the inner ring is mounted on the shaft, then press or hammer hand pressure. At this time, the auxiliary roller or auxiliary sleeve needle not to hold the needle fell out, with its own journal chamfer off the needle, needle roller bearings with slowly moving to the journal, the auxiliary roller or auxiliary sleeve will gradually withdraw, and loaded into the working position so far. Needle roller bearings can be installed, will assist the sleeve diameter coated with a thin layer of oil, set into the bearing outer ring, the auxiliary sleeve and the bearing outer ring to form a circular hole, and then installed with needle holes in the ring. Zhuangwan needle, the auxiliary sleeve can be used to launch the working shaft. The needle roller bearings without inner or outer ring, when in installation, the first rolling shaft or housing bore coated with a thin layer of grease, the grease needle are close to the installation site. Attached to the last needle should be gaps, the size of the gap in the circumference of the needle bearings with 0. 5mm is appropriate. Do not put the last needle tucked in, a needle or less loaded, because the squeeze loading, the bearing is stuck can not rotate; less loaded, the gap is too large, easy to cause bearing operation occurs when the needle torsion and broken. Here, in particular, for only the drawn cup needle roller bearings, due to thin outer wall, do not have the best hand hammer Use gasoline or kerosene to clean, should one hand knead bearing inner ring, the other hand slowly turn the outer ring, until after a rolling body of the bearing, roller, keep the oil shelf completely washed off the surface, then clean the bearing outer ring. It should also be noted when cleaning, began to slowly rotating, reciprocating shaking, not too much force rotation, otherwise, the dirt damage bearing raceway and rolling body is easy to be attached. Bearing cleaning quantity is larger, in order to save gasoline, kerosene and ensure the cleaning quality, can be divided into coarse, fine cleaning in two steps. For bearings with inconvenient to remove, wash oil available to tears. The temperature of 90 ° --100 ℃ hot oil poured hot, the old oil dissolved, with hook or a small spoon to dig out the old oil bearing, and the remains of the old oil, kerosene oil inside the bearing rinse, wash again can last gasoline. The cleaning quality of the bearing by hand test. Carefully observe the bearing after cleaning,, on the inner and outer ring raceway, the rolling body and a retainer gap there will always be some residual oil. Inspection, can be used to clean the feeler gauge inclined remaining oil scraping, apply to the thumb, index finger back and forth slowly rubbing grinding, fingers if a rustling sound, the bearing is not clean, should wash them again. Finally, bearing in his hand, pinch the inner ring, outer ring (a horizontal rotating large bearings can be placed in the assembly stage, the inner pad, the outer ring is pressed, inner circle, rotating outer ring), with flexible rotation, no block, no bounce pass. The bearing cleaning good, filled with lubricant, should be placed in the assembly stage, the following mat with net cloth or paper pad, for assembly covered with plastic sheeting,, are not allowed on the ground or on the box. Mobile bearing, not allowed to directly with the hand, should Dafanb gloves or use net cloth bearing package and then take, otherwise, with sweat, moisture hands after contact, easy to produce rust bearing fingerprint. The bearing with two shields or seals, as well as bearing coated with antirust, lubrication and oil, because at the time of manufacture have been injected into the grease, so don't clean before installation, for example, 51708ZHS and 12, Hong Wei - 12 type tractor and Dongfanghong 20 tractor clutch (original code 688808) bearing. Cleaning the 2 shaft and the bearing shell hole and other parts With gasoline or kerosene to clean, dry cloth to wipe, and then coated with a small amount of oil in order to facilitate the installation. These parts after cleaning, attention should be paid to every casting with sand to completely remove all burrs; sharp and bearing parts must be removed, lest, residual sand and metal fragments in the installation into the bearing assembly quality, effect. 1 note The inner, outer ring can be separated bearing outer ring of mutual exchange, don't mistake so as not to affect the quality of contact. On the ball and spherical roller bearings, must not be arbitrary to rolling element bearing Lu out mix, so as not to affect the accuracy of the installation position. When mounting bearings, to facilitate the inspection bearing code, not an error, the bearing ring side arrangement and installation type. The heating shell hole 2 bearing and the bearing seat For a large amount of surplus, large bearing, in order to facilitate the installation, must be installed before heating; for light metal bearing shell hole tight fitting (such as aluminum bearing seat), due to very low surface hardness, to prevent the bearing outer ring is pressed into a bearing shell hole is scratched, napping, should also be heating installation. Heating method, usually bearing or the separation bearing ferrule, placed in clean the oil tank, the oil flooded bearing, uniform heating. The temperature reached 80 - 90 ℃, remove wipe, while hot installation. The tank can be made of 2 - 3mm thick iron plate, from the bottom of 50 - 70mm high with a porous plate, bearing is arranged on the porous plate heating. Its purpose is to avoid the precipitation of impurities in the oil into the bearing. However, for the bearing surfaces with shields or seals, because in the manufacturing of lubricants have been added, the pre - installation can not be heated. 1 rolling bearings with 1 selection basis According to the rotation loads acting on the bearings relative to the ring, the load bearing ring bearing has three kinds: local load, cyclic load, oscillating load. Usually cyclic loading (axial rotation), oscillating load the tight fit; local load in addition to the special requirements for general use, a tight fit. When the bearing under dynamic load and the heavy load, inner, outer ring shall be used for interference fit, but sometimes the outer ring can be a little looser, should be able to make axial swimming in the bearing shell hole; when the bearing ring subjected to oscillating load and load is light, can be used to mix with a little loose tight some of the. (2) load The amount of interference is determined between the bearing and shaft or housing bore on the load size, load is heavy, the larger the amount of interference fit; load is light, the relatively small interference volume with. The general radial load P is less than 0. 07C at light loads, P greater than 0. 07C and less than or equal to 0. 15C for the normal load, P greater than 0. When 15C (C for heavy load bearing dynamic load rating). The working temperature? Bearing in operation, the ferrule temperature is often higher than the adjacent parts of the temperature, therefore, the inner ring of the bearing may be due to thermal expansion and the shaft from loosening, outer ring may be due to thermal expansion effect of bearing in the housing bore axially moving. Help select, the bearing device part temperature difference, swelling shrinkage should be taken into consideration, large temperature difference, selection of shaft matched with the inner ring of the surplus capacity should be greater. Rotary accuracy? The bearing rotation accuracy requirements, in order to eliminate the influence of the elastic deformation and vibration, should avoid the clearance fit. ? structure and material bearing housing hole On the form of shell holes, and the outer ring of the bearing is matched with an interference fit, should not make the outer ring to rotate in a shell hole. When installed in a shell hole, light metal shell hole or hollow shaft bearing, with the thick wall shell hole, cast iron shell holes or solid shaft closer. Convenient installation and disassembly? For heavy machinery, bearing should adopt the loose fit. The tight fit, can choose the separation type bearings, inner ring with cone and set with tight or unloading sleeve bearing. The axial displacement of the bearing? Fit, when a ring for bearing in operation can move in the axial direction, the outer ring of the bearing and the bearing shell hole should adopt a loose fit. 1 coordination selection With the bearing and the shaft with hole base, and cooperates with the housing is a basic shaft system. The machine manufacturing industry with the bearing and the shaft of the tolerance and fit system is different, the bearing inner diameter tolerance zone is in change, therefore, the same with the condition, with the inner diameter of the bearing and shaft fit more closely than usual. Bearing outside diameter tolerance zone and shaft basis system the central axis of the tolerance zone although the same is below the zero line, but its value and the general tolerance system is not the same. All kinds of bearing in the installation, selection of shaft and housing bore tolerance zone is shown in Table 2 - 1~2 - 4. Different tolerance levels of bearing and shaft and housing tolerances, see GB275 - 84, or bearing samples. 1 rolling bearing mounting points 1 installation methods 1 using copper and manual hammering installation This is a simple way to install in small bearings. When the inner ring of the bearing outer ring is tightly matched, is a loose fit, the copper rod close to the end surface of the inner ring, direct percussion hammer copper and copper, by force, will be fitted to the shaft bearing slowly. The inner ring of the bearing is large, available copper along the bearing inner ring face evenly around the hard hit, not only on the side, also cannot too hard to beat, symmetry, gently tapping slowly mounted, to avoid loading the inclined crack of bearing. When the outer ring of the bearing inner ring is tightly matched, is a loose fit, can be used with the method of the opposite, with hammer percussion copper bar close to the bearing outer ring face, the bearing is pressed into the bearing seat, finally fitted to the shaft, which is not easy to damage parts. 2 use the sleeve installation The method and installation of the same truth by copper bearing. It is the direct pressure on the bearing sleeve on the end (bearing installed in the shaft on the end face of the inner ring is arranged in the housing hole; when the pressure gauge 6 outer end face), with hammer percussion force can be evenly distributed in the installation of the bearing of the ferrule end face, and can be used in conjunction with the press, the installation of labor-saving and time-saving, reliable quality. Sleeve installation should be made for the soft metal (copper or low carbon steel pipe can be). If the bearing is mounted on the shaft, the inner diameter of the sleeve should be slightly larger than the shaft neck 1 4mm, slightly smaller than the outer diameter of bearing inner ring rib diameter, or taking the sleeve thickness as the standard, the thickness should be made equal to the bearing inner ring thickness of 2/3 - 4/5, and the two ends of the sleeve should be flat and cylinder body vertical. If the bearing is installed in the seat hole, the sleeve diameter should be slightly smaller than the outer diameter of the bearing. Install the bearing sleeve, such as component is small, can be placed in a vise mounted. Jaw pad with aluminium or copper sheet, to prevent axial pinch. If the product is large in size, should be installed on the gallows. The bearing on the shaft, then install the sleeve, hammer tap evenly slowly assembly sleeve. When the sleeve end cover is a flat topped, hammer should be along the circumference are evenly percussion set. Table 2 - 1 shaft tolerance installation radial bearing and angular contact bearing belt Note: any occasions with higher requirements for tolerance, J5, k5...... Instead of J6, k6...... Etc.. The single row tapered roller bearings and double row angular contact ball bearing, due to the impact of internal clearance is not very important, can use K6 and M6 instead of K5 and m5. The radial clearance of bearing roller bearing selection should be larger than the fundamental group. The van had higher tolerance level or speed, should choose H7, IT5 as the shaft neck shape tolerances. Size greater than 500mm, the shape of the tolerance to IT7. Table 2 - 2 shaft tolerance installed thrust bearing with Table 2 - 3 the housing bore tolerances installation radial bearing and angular contact bearing belt Table 2 - 4 the installation shell hole tolerance of thrust bearing with Cylinder on both sides, when the sleeve cover is spherical, at the center of percussion hammer should be spherical end cover. If the bearing inner, outer ring and the shaft and the bearing seat hole is a tight fit, one end of the end sleeve made of double loop, or with a single ring sleeve with a disc mounted bearings, as shown in Figure 2 - 1, 2 - 2. When installed, the ring sleeve or disc close to the bearing, the outer end face, press pressure hammer, the bearing to the shaft and bearing seat hole. This can be avoided when installing cage damage. This installation method is only suitable for the installation of retainer bearing not protruding ferrule end face. 1 use the press mounting This method is used together with the sleeve installation, can be hand hammer pressure bag. The bearings are not struck, and parts of bearing matched sealing devices are not damaged. The press mounting bearings, should make the press machine rod and the central line of the sleeve and the bearing coincides with the central line, the pressure is located in the center, in order to prevent the installation deflection fracturing bearing. The 2 heating installation For the installation of bearing interference larger or large size bearings, in order to facilitate the installation, can use the principle of heat expansion and cold contraction, the bearing heating with copper, sleeve and a hammer to install. Heating methods such as the second section of this chapter is about the housing bore heating of bearing and the bearing seat said, in general the temperature below 100 ℃, 80 ℃ - 90 ℃ appropriate. When the temperature is too high, easy to cause the bearing ring raceway and rolling body annealing effect, hardness and wear resistance, resulting in bearing life reduces and scrapped prematurely. Install bearing using the heating method, the oil temperature to reach the required temperature after 10 minutes, should be promptly removed from the oil in the bearings, while it is hot in the shaft. When necessary, can be installed in bearing inner ring end face with a bit of pressure, it is easier to install. Bearing in the shaft, must immediately pressed until the inner ring, cooling. At present, some foreign companies have developed a variety of bearing used in the installation of the bearing heating bearing devices, such as electric induction heater etc.. 1 different types of bearing installation Deep groove ball bearing installation Specifications of deep groove ball bearing, large quantity, wide application. The installation method is relatively simple, should consider the coordination selection. A matching with the inner ring and the shaft neck can be calculated the amount of interference: ? Type in Between the delta d inner diameter of the bearing and shaft neck and the amount of interference (m) D - bearing inner diameter (mm) B - bearing width (mm) R - bearing radial load (N) Between surrounding Δ T bearing inner and shell temperature difference, generally 5 - 10 After calculation, according to the amount of interference calculation, determining the nature and shaft, and the shaft is machined to the required size of installation. 1 full needle bearing installation Install full complement needle roller bearings, usually carried out using an auxiliary sleeve. The auxiliary roller, the auxiliary sleeve diameter should be better than the shaft diameter of 0 small. 1 0. 3mm. When installing the bearing outer ring, inner surface coated with grease, by placed within the surface mount needle (put the last needle should be gaps), and then to replace the shaft or bearing inner ring of the auxiliary roller or auxiliary sleeve into the outer hole, and the end surface mounting shaft or bearing alignment the end face of the inner ring is mounted on the shaft, then press or hammer hand pressure. At this time, the auxiliary roller or auxiliary sleeve needle not to hold the needle fell out, with its own journal chamfer off the needle, needle roller bearings with slowly moving to the journal, the auxiliary roller or auxiliary sleeve will gradually withdraw, and loaded into the working position so far. Needle roller bearings can be installed, will assist the sleeve diameter coated with a thin layer of oil, set into the bearing outer ring, the auxiliary sleeve and the bearing outer ring to form a circular hole, and then installed with needle holes in the ring. Zhuangwan needle, the auxiliary sleeve can be used to launch the working shaft. The needle roller bearings without inner or outer ring, when in installation, the first rolling shaft or housing bore coated with a thin layer of grease, the grease needle are close to the installation site. Attached to the last needle should be gaps, the size of the gap in the circumference of the needle bearings with 0. 5mm is appropriate. Do not put the last needle tucked in, a needle or less loaded, because the squeeze loading, the bearing is stuck can not rotate; less loaded, the gap is too large, easy to cause bearing operation occurs when the needle torsion and broken. Here, in particular, for only the drawn cup needle roller bearings, due to thin outer wall, do not have the best hand hammer to install, use the press to be pressed into. Because the hand hammer, pressure is not uniform, easy to make the outer ring needle roller bearings produced by local deformation. 2 tapered roller bearing installation Tapered roller bearings are separable bearing, inner and outer ring can be separated. So the installation, can be respectively the inner retainer rolling body assembly is pressed on the shaft, the outer ring of individual load bearing hole, as shown in Figure 2 - 3. The sleeve should press,, must make one end of the sleeve on the outer end face, not on the tilt of the raceway surface. Tapered roller bearings are installed in pairs, as shown in Figure 2 - 4. In the installation should pay attention to three aspects: choosing fit; adjust the axial clearance; commissioning and testing temperature. Choose the installation with? Tapered roller bearing outer ring and bearing shell hole should not be used for interference fit, the inner ring and the shaft neck with also shoulds not be too tight, require the use of nut adjustment in the installation should be able to make it produce axial displacement is flexible. Because of the tapered roller bearing by using interference fit, easy to make the bearing contact angle change, cause bearing uneven load distribution, caused by high temperature. Therefore, this kind of bearing inner, outer ring and the shaft and the bearing shell hole with the installation, should in general be in hands thumb will just push in shaft neck and bearing shell hole for the best. Adjust the axial clearance? For the installation of the axial clearance of the tapered roller bearings, shaft neck threads available on the adjusting nut, the adjusting shim and the bearing base hole, or with a preloaded spring regulating methods. The axial clearance size, and bearing installation layout, the distance between the shaft and bearing, bearing materials, can be determined according to the working conditions. For tapered roller bearing high speed high load, adjust the clearance, must consider the effects of temperature on the axial clearance, the temperature rise caused by clearance reduction estimation, that is to say, the axial clearance to adjust to a point. For low speed and bearing vibration of bearing, should take no clearance or preload installation, installation. Its purpose is to make the roller of tapered roller bearings and roller have good contact, load distribution, prevent the roller and raceway damage by vibration and impact. After adjustment, the micrometer size of axial clearance test. The method is first dial indicator is fixed on the machine or the bearing seat, the dial contacts to smooth surface along the axial axis, around the push shaft, the maximum swing is the axial clearance value. Commissioning and testing temperature? In order to make the roller tapered roller bearing raceway contact with the good, and the axial clearance fit, the tapered roller bearing installation and adjustment after each clearance, shall be commissioning and testing temperature. Method is the first low speed 2 - 8 minutes, and then try to medium speed for 2 hours, then gradually raised to high speed. Each level of speed test run shall be not less than 30 minutes, the temperature rise rate per hour should not exceed 5 ℃, stable temperature should not exceed 70 ℃ last. In addition, install and adjust the clearance of the tapered roller bearings, should also pay attention to, must make the tapered roller and inner ring rib good contact. 1 angular contact ball bearings installed Angular contact ball bearing installation is more complex than the deep groove ball bearings, are installed in pairs, and the pre load. Installed well, can make the host working accuracy, bearing life is greatly increased; otherwise, not only the precision is not up to the requirement, the life will also be affected. 1 installation form The installation form of angular contact ball bearing, a back to back, face to face and are arranged in series three. Back to back (two wide end bearing relative) installation, bearing contact angle line along the axis direction diffusion, bearing angle can increase the radial and axial rigidity, maximum deformation resistance; face to face (narrow end two bearing relative) installation, bearing contact angle line towards the axis of rotation direction of convergence, the to the small angle rigidity. Because of the inner ring of the bearing outer ring out, when pressing the outer ring two bearing outer ring together, the original clearance elimination, can increase the bearing preload; tandem array (two wide end bearing in one direction) installation, bearing contact angle lines in the same direction and in parallel, the two bearing sharing the same the direction of the work load. But the use of this type of installation, in order to ensure the stability of the axial installation, two pairs of bearing series must be installed at both ends of the counter shaft. 2 pre load Pre load through the grinding end surface of a ring of bearing, or between two different thickness of the spacer ring is placed between a pair of bearing inner, outer ring, the bearing clamped together, so the steel ball in close contact with the raceway and. Great influence of preload the size of the bearing life, according to the information, when the bearing assembly has 0. 012mm interference, the service life is reduced by 38%, 0. 016mm interference, the service life is reduced by 50%; when the bearing assembly has 0. When the 004mm gap, service life significantly decreased, 0. When the 008mm gap, service life is down 70%. Therefore, appropriate selection of pre load size, very important. The general high speed should be chosen small preload, low speed should be selected large preload. At the same time, pre load should be slightly greater than or equal to the axial load. Calculation of preload Selection of pre load, calculation formula of minimum preload is as follo, ws: Aomin=1.58tgaR + 0.5A (N) Type R&#0; &#0; radial loads acting on the bearings on the (N) A&#0; &#0; axial loads acting on the bearings on the (N) A&#0; &#0; through the ball and roll angle straight points of contact between the line each ball with center plane of (the nominal contact angle): 7000C a=15 ° 7000AC a=25 ° 7000B a=40 ° The pairs of bearings in each bearing are given by the formula. Type in "+" sign for axial load so that the original pre interference value that a bearing to reduce; "&#0;" for axial load so that the original pre interference value that a bearing increase. The minimum preload amount Aomin two pairs of bearings should be according to the two bearing the two maximum values in the selected (according to the assembly experience, usually take about 50N preload). Pre load adjustment Idle test. Angular contact ball bearing the assembly qualified after the inspection, to the operating speed for the air operation test, time is not less than 2h, the temperature should not exceed 15 ℃. 1 thrust ball bearing installation The shaft and shaft using transition fit, the shaft washer and the movable fit, and often paired mounting. At the same time in the installation, should also pay attention to test the axial clearance, verticality and shaft ring rotates with the shaft and the shaft center line. 2 tapered bore bearing mounting Tapered bore bearing for inner diameter is conical hole self-aligning ball bearings, cylindrical roller bearings and spherical roller bearings. This kind of bearing can be directly installed in the shaft neck taper, can also sets or unloading sleeve with conical tight, mounted on the shaft neck cylindrical. Request with tapered bore bearing, in general more closely. The radial clearance after installation is required for measurement of bearing. Because it is not with the degree of tightness by shaft tolerance decision, but according to the bearing radial clearance caused by bearing installation pressure into the cone on the matching surface of the distance to the reduction to decide, pressed into the distance is larger, more and more bearing radial clearance reduction, with more and more tightly; conversely, the smaller pressure into the distance the radial clearance reduction, less, bearing fit is relatively loose. Thus it can be seen, with the degree of tightness of tapered bore bearing, depends entirely on the radial clearance of the bearings installed before and after reduction is guaranteed. In order to ensure the quality of installation tapered bore bearing, here cento part of the former Soviet Union self-aligning ball bearing radial clearance allows the original reduction (Table 2 - 5), cylindrical roller bearing radial clearance and provisions of German FAG company with tapered bore reduction (Table 2 - 6), and a circular cone roller bearing radial clearance reduction (Table 2 - 7), the reference can be used for measuring the tapered bore bearing radial clearance before and after the installation of. When in use, the general should not exceed the values in the table. Measurement of radial clearance. The aligning ball, can not be separated type spherical roller bearings with plugs Jue measurement, when the bearing with feeler roller, to ensure that the inner two raceways inclined relative to the outer ring is not addressed, should be measured in the two rows of rollers. For small spherical roller bearings, as the radial clearance is very small, not a feeler, axial displacement measurement of bearing surface on the available to replace (axial displacement numerical table 2 - 6, 2 - 7). If the axial displacement can not be measured, the bearings should be installed in the shell bearing seat, and then pressed into the housing bore. After pressed, poked by hand, should make the outer ring can rotate smoothly. Cylindrical roller bearing radial clearance of separable, then using micrometer to measure, namely after expansion by measuring the inner ring installed in the shaft neck instead. Table 2 - 5 self-aligning ball bearing radial clearance allows to reduce the amount of the original (excerpt) unit of MM Table 2 - 6 with tapered bore cylindrical roller bearing radial clearance reduction (excerpt) unit of MM Here should be noted, for the installation of undesirable or after removing bearing re installation, the small radial clearance, axial displacement or the inner ring expansion, must be re determination. There are three ways to install tapered bore bearing common: 1 bearing directly installed on the tapered shaft neck This method can be used, for small and medium-sized bearing mounting sleeve, also can use the lock nut and the hook spanner to cone bearing. But the best should be used to install the lock nut, because it can precisely control the radial clearance of tapered bore bearing reduction, as shown in Figure 2 - 10. Fig. 2 bearings are mounted in a cone sleeve This method can take the way, by pressing the locking nut. Between the withdrawal sleeve is located on the axle neck and bearing inner diameter, as shown in Figure 2 - 11. 3 bearings are mounted on an adapter sleeve The installation, use locking nut to tighten the bearing cone sleeve, as shown in Figure 2 - 12. 1 conical bore double row cylindrical roller bearing installation This kind of bearing for machine tool spindle, such as NN3020K (original code 3182120) bearing. Installation and spherical roller bearings with tapered bore and its installation, in principle is basically the same, the tightness is matched with the radial clearance of bearing installed on before and after reduction to achieve. In the installation, the radial clearance reduction generally replaced by measuring the axial displacement of the shaft bearing inner ring. Axial displacement calculated: ? L=K (eH - en+a) (mm) Type eH -- the original radial clearance EN -- bearing assembly clearance A -- a constant, 0.01 K -- with the hollow shaft wall thickness and the proportion coefficient The value of K and spindle bearing with the diameter of D, and the average diameter of spindle shaft neck D. Of. The value of K in Table 2 - 8, eH - 9 Table 2, en values in Table 2 - 10. When installed, the axial displacement of the bearing, the available micrometer contact bearing inner ring face determination. Thickness adjustment by two bearing inner, outer ring spacer. There are three methods to determine the two bearing inner, outer ring spacer thickness difference: The first is the method of measurement The bearing is arranged on the round seat body, pressing a weight equal to A (preload) iron, the bearing clearance, the steel ball and the raceway has certain elastic deformation, and then use the dial indicator measuring bearings, end of the size difference. When the bearing is installed behind the back, with two bearings measuring wide end side of the inner, outer size difference △ K1; when the bearing face to face (narrow end relative) installation, deal with the two bearings are measuring the narrow end side of the inner and outer ring size difference △ K2; when the bearing for the tandem arrangement, on a bearing outer ring size measuring the wide end side of the poor, to another bearing measuring its narrow end side of inner and outer ring size difference. For a pair of bearings arranged back-to-back. We measured a wide face at the inner, outer ring of bearing size moment for the +0. 07mm, another end bearing width at inner and outer circle size difference is +0. 08mm, inner ring spacer thickness is 6. For 25mm, the circle thickness. Outer ring spacer thickness =6. 25+ (0. 07+0. 08) =6. 40 (mm) Measurement of size, each bearing three measurements, at intervals of 120 ° measured again, finally take the average. Figure 2 - 7 as a series of bearing installation. We measured a wide inner ring and the outer ring of bearing end surface size difference is +0. 16mm, another bearing narrow end internal ring size difference of - 0. 12mm, inner ring spacer thickness is 6. 25mm, for the outer ring spacer thickness. Outer ring spacer thickness =6. 25+ (0. 16 0. 12) =6. 29 (mm) Second is the sense of law This method mainly rely on the experience to determine the inner and outer ring spacer thickness. There are three common sense method; one first outer spacer ring cylindrical surface by 120 ° respectively drilled three holes of diameter 2 - 3mm, and the two sets of paired with its mode of installation (back to back, face to face or series sort) to inner and outer ring, the iron block, the upper pressure equal to the pre bearing load and then use? 1. About 5mm bar, sequentially through three holes to touch the inner spacer, check the inner and outer ring spacer in between end faces resistance. By hand feeling, inner and outer ring spacer resistance should be similar, otherwise the spacer ring end face grinding. The two is to the left hand middle finger and index finger pressing the two sets of bearings (approximately equal to 50 pre load), the elimination of all its clearance, the right hand toggle, respectively within the external ring, to determine whether similar resistance. Three is to squeeze two sets of bearings with both hands thumb and index finger, to eliminate all of its space, use a hand finger into the inner hole of the bearing, the original release partial inner spacer, check the resistance and the outer ring is similar to. Third is the spring pre load method. For the series arrangement of bearings, in addition to the measurement or the feeling of inner, outer ring thickness determination, in a still in bearings, with a plurality of cylindrical spring preload, to achieve. Calculation formula of spring: Every spring should be generated force Type D -- spring wire diameter (CM) D -- spring mean diameter (CM) R -- spring allowable stress (40000 70000N/c m) The number of N -- a cylindrical spring Spring wire diameter The spring pitch Type G&#0; &#0; torsional elastic modulus, equal to 7. 5 x 106N/c square meters The amount of spring compression Several problems should be paid attention to during installation A. must be good with inner and outer ring spacer thickness, spacer two Miao parallelism should not exceed 0. 002mm. B. bearings must be selected. Each of the inner diameter of the bearing outer diameter difference, difference shall be 0. 002 0. Between 003mm, and with shell holes keep 0. 004 0. 008mm, and the shaft neck to keep 0. 0025 0. 005mm gap. In the actual installation, should with both hands thumb will fit bearing can just push the best. Roundness, shell holes at the two ends of C. bearing seat hole and the shaft neck of coaxiality, and radial shaft runout should not exceed 0. 003mm. Parts in contact with the end D. bearing ring face should smear test, contact area shall not be less than 80%. E. must be directed to install. The highest point is about all the bearing inner ring radial runout at the nadir axis neck radial runout, the highest point of the outer ring of the bearing radial runout is arranged in the housing hole to form a straight line. Matters needing attention in installation Drilling, on the bearing groove, chamfer, car end does not allow 1 installation. Otherwise, easy to cause deformation of bearing ring, bearing accuracy and the service life of the working surface at the same time, cutting off metal easily into the bearing, to accelerate the raceway and rolling body of the bearing wear, causing premature damage. Numerical table 2--8 proportional system Table 2 - 9 double row cylindrical roller bearing the original radial clearance Table 2 - 10 radial internal clearance of double row cylindrical roller assembly Direct hit bearing ring hammer does not allow 2 installation. The benchmark of end bearing close to the shaft shoulder mounted in qing. Base end bearing is according to the bearing end without typing to distinguish, deep groove ball bearings, self-aligning ball bearings, cylindrical roller bearings, spherical roller bearings and needle roller bearings, the word end as the datum plane; angular contact ball bearings and tapered roller bearings, a word end to the reference plane. 3 mounting pressure should be added to have installed the ferrule end face of interference fit, which is mounted on the shaft, the pressure shall be added to the bearing inner ring end face; a hole arranged in the inner bearing, pressure should be added on the outer ring of the bearing surface. Not allowed through the rolling body and a holding pressure transfer. 4 for the inner ring, outer ring is tightly matched bearing, slide with the installation, is not separable should first be bearing mounted on the shaft, the shaft together with the bearing shell Konne into the bearing seat; division of separable, inner, outer ring can be installed separately. 5 in order to prevent the bearing inclined installation, installation center line axis and the bearing hole must be coincidence. If the installation is not correct, to be re installed, must pass through the end face of the inner ring, the bearing out. 1 bearing after installation inspection Bearing installation is correct or not, have a direct impact on the accuracy of its life and host. If improper installation, bearing not only has the vibration, noise, low precision, the temperature gradually increased, but also be blocked out of danger; conversely, installed well, can not only ensure the accuracy, service life will be greatly extended. Therefore, the bearing after installation, must be inspected. Key test items are as follows: 1 test installation position Bearing after installation, first check the parts and fixed parts are touching, the lubricating oil can flow into the bearings, sealing device for fastening and axial device is installed correctly. 2 test the radial clearance In addition to bearings with a preloaded outside, should check the radial clearance. Deep groove ball bearings can be rotated by hands to inspection, smooth and flexible, no vibration, no swing as well. Cylindrical roller and roller bearings can be inserted into the feeler feeler inspection, the roller and bearing ring, feeler inserted depth should be greater than the roller length 1/2. When the radial internal clearance of the bearing can not use feeler gauge measurement, can measure the bearing in the axial displacement, radial clearance reduction instead. Under normal circumstances, such as the bearing inner ring is a conical hole, then on the cone axial movement is about 15 times the amount of radial clearance reduction. The radial internal clearance of the bearing after installation, some unqualified can be adjusted, such as the angular contact ball bearings, tapered roller bearings; some are in manufacturing has been in accordance with the standard provisions adjusted after installation, unqualified cannot adjust, such as deep groove ball bearings, self-aligning ball bearings, cylindrical roller bearings, self-aligning roller bearing. This type of bearing is installed after the test if not qualified, radial assembly clearance is too small, the choice of bearing with improper or incorrect parts processing, assembly. At this time, the bearing must be unloaded, find out the reason, to eliminate the re installation. Of course, bearing clearance is too large. 3 inspection of bearing and the shaft shoulder close degree In general, tight interference fit bearing must be installed close to the shaft shoulder. Test method: (1) the light method. The lamp alignment bearing and shaft shoulder, see the leakage judgment. If no leakage, installation is correct; if the light evenly along the shaft shoulder around, the bearing and shaft shoulder is not close, with the pressure bearing close; if partial leakage, the bearing installation tilt, can be hand hammer, brass or percussion bearing inner ring sleeve, is slowly. (2) to test the feeler gauge. Feeler gauge thickness shall be 0. 03mm began. Test, test in several in the bearing inner ring end face and shoulder the entire circumference, if there is a gap and very uniform, the bearing is not installed in place, deal with the bearing inner ring of pressure it close to the shoulder; if the increased pressure is not tight, the journal fillet fillet is too large, the bearing stuck, should be trimmed journal fillet, make its become smaller; if it is found that the end surface of the inner ring and the bearing shoulder thickness gauge individual parts can pass, not at this time must be removed, to be repaired, re install. If the bearings are mounted with an interference fit on the bearing seat hole, the bearing outer ring by the shell hole shoulder block is fixed, the outer end face and shoulder shell hole end is close, whether the correct installation, can also be used feeler inspection. 4 thrust bearing test after installation Install thrust bearing, the verticality inspection shaft and shaft centerline. Method is to dial fixed on the tank shell face, touch the top of the table at the top edge of the bearing ring raceway bearing, side observation indicator pointer, pointer to swing, the shaft and shaft centerline is not vertical. The box when a shell hole deeper, 1000 meter test can also be used to lengthen the. Thrust bearing is installed correctly, the seat can automatically adapt to the rolling body, ensure that the rolling body is located in the upper and lower ring raceway. If wrong, not only the bearing is not working properly, and all mating surfaces subjected to severe wear. Because the shaft ring and ring and the difference is not very obvious, the assembly should be careful, do not make a mistake. In addition, there are 0 holes should be between the seat and the bearing thrust bearing. 2 0. 5mm gap, installation errors caused by imprecise to compensate parts processing, when in operation, the bearing ring center migration, this gap can ensure its automatic adjustment, avoid contact with friction, the normal operation of. Otherwise, will cause severe damage to bearings. The test run Test run, test bearing noise, vibration, Wen Sheng whether it meets the requirements of. General bearing operating temperature should be lower than 90 ℃, the temperature is too high, will cause the bearing heating annealing or burning, reduce the service life. 1 bearing installation example 1 type CA10B Jiefang Truck gimbal parts of cross bearing installation Start with a little butter will needle stuck on the bearing shells, mounted on the oil seal, and in turn the cross shaft is arranged in the inner gimbal * (butter mouth to drive shaft), the bearing shell is installed on the transmission shaft *. In order to prevent the damage to the machine, with the hand hammer shell bearing installation, don't overexert, shall not be installed in the partial. Then the old shell bearing or bearing shell diameter smaller than copper, sandwiched by the vise, to expose the lock ring until, finally by the fastening piece, pins or screws. After installation, the cross shaft by hand, the degree of tightness test, in order to enable the cross shaft free to rotate as appropriate. Avoid shell bearing and oil seal. 2 harvest &#0; &#0; 35 type tractor gearbox needle roller bearing installation Figure 2 - 13. First with 3 × 20 needle, reverse gear inner ring and outer ring spacer mix with butter when installed, and then along the end hole wall pasted 29 needle, arranged between the inner ring, and then paste the 29 needle, finally ends with a outer ring spacer is formed. When installing, rolled leather with positive, not skewed, the hole wall to block full production, should make the appropriate clearance between needle. The gap size for needle roller diameter half advisable, too easily broken needle, too easily squeezing roller not to move. The 3 Taishan &#0; &#0; 50 type tractor central transmission and differential bearing installation 1 installation of the small bevel gear assembly of bearings, the first 30310 (original code 7310), 32310 (original code 7610) bearing outer ring into the bearing housing hole, the inner ring oil heated at 70 - 90 ℃, then the end of the 32310 bearing inner ring is arranged on the small bevel gear shaft gear is removed from the oil in the near then, the gear shaft into the bearing housing hole, and the front loading of 30310 bearing inner ring, and screw on the fastening nut is. 2 assemble differential left 32216 (original code 7516) bearing and the right 30216 (original code 7216) bearing inner ring, the oil is heated to 70 ℃ - 90 ℃ reload. Install outer ring, corresponding to the outer end face and bearing seat and a shim thickness, axial movement to adjust the closing speed assembly. When the differential assembly into the rear axle housing, tighten the screws on both sides of the bearing seat, should rotate smoothly, with the hand feeling, no block, and should not be inertial rotation.

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