Introduction:

Basic concept of needle rolling

Needle roller bearings are equipped with thin and long rollers (roller length is 3-10 times the diameter, and the diameter is generally not greater than 5mm), so the radial structure is compact. Its inner diameter size and load capacity are the same as other types of bearings, and its outer diameter is the smallest, making it particularly suitable for support results with limited radial installation dimensions. According to different usage scenarios, bearings without inner rings or needle rollers and cage components can be selected. At this time, the journal surface and outer shell hole surface that match the bearing are directly used as the inner and outer rolling surfaces of the bearing. To ensure the same load capacity and operating performance as bearings with ring rings, the hardness, processing accuracy, and surface quality of the shaft or outer shell hole raceway surface should be similar to those of the bearing ring raceway. This type of bearing can only withstand radial loads.

Model comparison

1. Centripetal needle roller and retainer assembly (K-type);
2. Needle roller bearings with double locking rings on the outer ring (NA type, NKI type, RNA type, NK type);
3. Single row needle roller bearings with dual gear edges on the outer ring (NA type, NKI type, RNA type, NK type);
4. Double row needle roller bearings with dual gear edges on the outer ring (NA type, RNA type);
5. Stamped outer ring needle roller bearings (HK type, BK type).
This type of bearing has low cost, high load-bearing capacity, and is suitable for supporting structures with limited installation dimensions. The journal surface is hardened as a rolling surface, and the bearing is inserted into the seat hole by pressing fit without the need for axial positioning. Before installation, the bearing should be injected with an appropriate amount of lubricating grease. Generally, BK type bearings do not need to be lubricated again after assembly. They are used for supporting shafts without protruding ends, and the end face is sealed to provide a sealing effect, and can withstand small axial displacement forces.

Advantage:

1. High speed, high precision

2. Long service life

3. Low noise and good performance