Physical ring needle roller bearing is composed of one or two rings and needle roller set with cage components. It has a smaller size and higher load carrying capacity. Therefore, such a bearing to meet light weight, small footprint, deliver power requirements. Depending on the application, can be used with or without an inner ring of the bearing inner ring.
    

The main structure type

 Outer double wall (or double-lock loop) with cage needle roller bearings NA, NKI-type

    Inner and outer rings can be mounted separately (locking ring, a full set of needle roller and cage), authority, high speed, divide single and double row two.
    If the shaft can not be used as a raceway, ie If the shaft hardened by grinding impossible or uneconomical time, you can use this type of needle roller bearings with inner ring.

 There are no inner cage needle roller bearings
    NA, NKI-type bearings without inner ring is RNA, NK-type needle roller bearings.
    Such bearings without inner ring for radial mounting dimensions restricted support structure to match the journal and the bearing directly as a rolling surface. As raceway axis, the hardware must be quenched and polished, but only when it is processed to the appropriate size and shape accuracy, the whole life of needle roller bearings and run to higher accuracy. Also, because without inner diameter of the shaft and therefore also can be appropriate to increase, thus increasing the rigidity.
 Sealed needle roller bearings with or without an inner ring
    Single-sided or double-sided sealed needle roller bearings can effectively prevent the intrusion of dirt, has filled the inner bearing the appropriate amount of lithium grease. This kind of bearing inner ring outer aspect ratio, which makes bearings in the shaft relative to the bearing box with a little displacement can also ensure a good seal to prevent injury while bearing contamination. Bearing inner ring has a lubrication hole also can be configured as desired by the outer or inner supplementary lubrication.