Needle roller bearings are roller bearings with cylindrical rollers that are small in diameter. In spite of their low cross section, needle roller bearings have a high load carrying capacity and are therefore extremely suitable for bearing arrangements where radial space is limited. Contour surface have a slight contraction?in the proximal surface of needle. Modification of needle and roller line contact results in preventing destructive edge stress. all can be used for general engineering bearings except catalog listed as following:
 (1)open drawning cup needle needle roller bearing (2) sealed needle roller bearing (3) needle bearing with inner ring (4) needle bearing without inner ring. SKF can also proveide various types of needle bearings.such as: 1. Needle roller cage assemblies 2. No raised edge needle bearing 3.self-aliging needle bearings 4. Combined needle roller / ball bearings 5. Combined needle roller / thrust ball bearings 6. Combined needle roller / cylindrical roller thrust bearings

Drawn cup needle roller bearing
Drawn cup needle roller bearing is a needle bearing which outer ring is extremely thin stamping. Its main characteristic is lower depth of section but higher load capacity. Mainly used for compact structure, cheap price and inner hole can not be used as configuration in needle cage raceway. Bearings and bearing box shall be installed on interference fit way. If can leave out box shoulder, stoperring such kinds of axial orientation function,  therefore, inner hole of bearing box can be made simply and cost-efficient. Such as KH series and BK series.etc.

Combined needle roller bearing.
Combined needle roller bearing includes NKIA type, NKIB type, NX.. Z type, NKX type, NKX.. Z type, NKXR type, NKXR.. Z type, NARN type and ZARF type.

Code and structure characteristics
K/KS single single/profile fraction
KK/KKS double row/double row cutting fraction
KZK connecting with crank pin
With KBK connecting rod piston pins
KNL long cylindrical roller and retainer components