Needle roller bearings is a cylindrical roller with roller bearings , relative to its diameter , roller both thin and long. This is called needle roller . Despite having a smaller cross-section , has a higher load bearing capacity, therefore , particularly suitable for radial space -constrained applications .
Definition of needle bearings
Needle contour surface at a slight contraction in the proximal surface . Results of needle and roller line contact can be corrected to avoid damaging edge stresses . Thick lines bearing outer ring needle roller bearings , high temperature nitrogen quenching, high precision roller guided by sorting high rigidity outer wall , the use of linear contact wheel can rotate easily in the raceway , and can be directly under enormous loads. To remove the stress , support rollers outer ring adopts arc design , curve roller there with a single , double ring, without the ring, seal ring with a variety of models . With seal grease storage space, providing long-term lithium grease lubrication , and extended lubrication intervals . Seal with a skeleton made ​​of nitrile rubber or ST12, its operating temperature range of -30 ° C to +100 ° C or -30 ° C to +180 ° C. Curve wheel -mounted can withstand extremely heavy loads and high-performance operation . RSTO outer wall , without inner supporting roller
Needle bearing characteristics and uses :
Needle roller bearings with thin and long roller ( roller diameter D ≤ 5mm, L / D ≥ 2.5, L is the length of the roller ), so radial structure is compact , its diameter size and load capacity with other types of bearings , minimum diameter, especially for radial bearing mounting dimensions restricted results . Depending on different occasions , can be used without an inner ring of the bearing or needle roller and cage assemblies , then journal surface and the surface of the bearing shell hole match directly as the bearing outer rolling surface , to ensure the load capacity and operating performance and a ring bearing the same shaft or housing bore raceway surface hardness , machining accuracy and surface quality should be similar to the roller bearing rings . Such bearings can only bear radial load.
Type needle roller bearings
In addition to catalogs listed , bearings can be used in general engineering , such as: open Needle roller bearings ( 1 ) , closed Needle roller bearings ( 2 ) , needle bearing inner ring ( 3 ) and non- needle bearing inner ring / no cage without inner ring needle roller bearings ( 4 ) , a cage and no cage filled with needle bearings (5) SKF also supplies various types of needle roller bearings , 1 needle cage assembly 2 , needle roller bearings without ribs 3 , 4 self-aligning , combined needle roller / ball bearings 5 , combined needle roller / thrust ball bearings 6 , combined needle roller / cylindrical roller thrust bearings
STO outer wall , roller bearing inner ring
RNA22 ... 2RS double sealed , no inner wheel bearing
NA22 ... 2RS double sealed , wheel bearing inner ring
NATR
NATR ... PP flat ring roller bearing axial guidance
NATV
NATV ... PP flat ring roller bearing axial guidance , full needle
NUTR rolling element bearing roller guide , full roller type
CRY inch flat ring roller bearing axial guidance
Needle roller bearings Precautions
Needle bearing load capacity, suitable for mounting dimensions restricted supporting structure,
As the journal surface hardened by rolling surface , press fit into the bearing housing bore , it no longer axial positioning. Before installing the bearing should inject the right amount of grease , under normal circumstances, no longer lubricated bearing assembly for BK journal bearing no protruding end , the closed end the seal and can withstand a small axial swimming .