The needle rollers and cage assembly components are the bearing's independent elements (units). The needle rollers are guided by the cages. The bearing without the (inner and outer) rings, small radial (cross)section , large capacity of heavy load, suitable for the braced framing ( support structure) in which the radial installation size will be limited. The surface of the bearing journal and the surface of the outer shell which are assorted with the bearing can be used directly as the internal and external rolling surfaces, its surface hardness shall be HRC 58-64 , the surface effective hardening depth shall be 0.6 - 1 mm , the hardness of the raceway shall be 0.32 μm (Ra) normally. When the shaft rotating accuracy is required, the hardness of the raceway shall be 0.20μm (Ra).
| Table 1 Axial Dimensional Tolerance | ||||
| Axial journal nominal dimension（mm） | Radial Clearance | |||
| Exceed | To | Less then 0 level | 0 level | Bigger than o level |
| 3 | 80 | j5 | h5 | g6 |
| 80 | 250 | h5 | g5 | f6 |
| Table 2 Raceway Shape Tolerance | |||||||||||
| Rolling Raceway Diameter (mm） | Over | 3 | 10 | 18 | 30 | 50 | 80 | 120 | 180 | 250 | 315 |
| To | 10 | 18 | 30 | 50 | 80 | 120 | 180 | 250 | 315 | 400 | |
| AccuracyCylinder μm | 2.5 | 3.0 | 4.0 | 4.0 | 5.0 | 5.0 | 8.0 | 10.0 | 12.0 | 13.0 | |
Needle roller and cage assemblies have single row type K and double row type K…ZW. Using a special type of needle roller and cage when a normal needle roller and cage cannot be used, 'D' will be added at the end of the designation like K…D or K…ZWD to represent this kind of bearing.
Prefix:KBK- needle roller and cage assemblies used for piston pins.KZK- needle roller and cage assemblies used for a crank pinsWJ- needle roller and cage assemblies in inch
