The needle bearing has thin and long rollers, so the radial structure is relatively compact. When the needle bearing has the same load capacity and inner diameter as other types of bearings, its outer diameter (outer edge diameter) is the smallest, so it is more suitable for installation in some places where the size is limited. Improper bolt and roller bearing methods can also cause roller bearing heat. Lubrication can reduce wear in the movement of parts, ensure the accuracy of the press, and reduce energy consumption. Lubrication is divided into thin oil lubrication and thick oil lubrication. Due to different usage, we can choose other components such as bearings or needle rollers without inner ring according to different needs. At this time, the surface of the journal matched with the bearing and the surface of the housing hole are used directly as the inner rolling surface and the outer rolling surface of the bearing. In order to ensure that the bearing capacity and running performance of the needle bearing without the inner ring and the ferrule are the same, it should be noted that the hardness, surface quality and machining accuracy (accuracy) of the component should be basically consistent with the raceway of the bearing ring.
Model comparison
1. Radial needle roller and cage assembly (type K);
2. Needle roller bearings with double lock rings on the outer ring (NA type, NKI type, RNA type, NK type);
3. Single row needle roller bearings with double ribs on the outer ring (NA type, NKI type, RNA type, NK type);
4. Double row needle roller bearings with double ribs on the outer ring (NA type, RNA type);
5. Drawn cup needle roller bearings (HK type, BK type).
This type of bearing has low cost and large bearing capacity, and is suitable for the support structure with limited installation size. The surface of the journal is hardened as a rolling surface. The bearing is press-fitted into the seat hole without axial positioning. The bearing should be filled with an appropriate amount before installation.
Lubricating grease, normally, no longer need to lubricate BK bearing after assembly for bearing without protruding end of the journal, the end face is closed to seal, and can withstand small axial swimming force.
See more bearing parts in WMB.
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