It is required that the surface hardness is not less than HRC60, and the surface roughness Ra value is not more than 0. Needle roller bearings without inner ring RNA, NK type needle roller bearings without inner ring are suitable for components with restricted Clutch Release Bearings radial dimensions. It is also commonly used when the shaft or housing has oscillating motion. Because there is no inner ring, the surface of the matching journal is directly used as the rolling surface. This kind of bearing does not limit the axial displacement of the shaft or housing, and the limit speed is higher. It does not limit the axial displacement of the shaft or housing. When the speed of the main engine is high, needle roller bearings with retainers should be used as much as possible. Assembled G2 level needle rollers, the group batch diameter variation is within 2μm, except for the full complement needle roller bearings, all adopt high-rigidity holders, which can correctly guide the needle rollers parallel to the axis. Since the needle rollers are separated by the holder, friction is reduced, so it can be used in parts with higher speed.The solid ring needle roller bearing has a compact structure, small radial dimension, and large load capacity. Compared with other types of rolling bearings, the load of needle roller bearings is the same under the same radial dimension. Needle roller bearings-generally can only accept radial load, not axial load. It is requested that the surface hardness, machining accuracy and surface roughness of the journal or shell rolling surface should be the same as the bearing ring. Because the inner ring has no ribs, the inner ring, outer ring, complete set of needle rollers and holders can be installed separately for this type of bearing, without limiting the axial displacement of the shaft or housing. This type of bearing has a variety of structures and size series.. When there is an axial load, it should be used in combination with other bearings. It is suitable for parts with restricted radial profile dimensions.63μm. The capacity is the largest, and its rigidity is higher, but the friction torque is also higher. The limit speed of needle roller bearings is relatively low. Needle roller bearings with inner ring NA and NKl
