Common faults of needle roller bearings and their causes

 

1. Failure mode:

 

(1) Bearing rotation is difficult and heating;

 

(2) Abnormal sound occurs in bearing operation;

 

(3) Bearing vibration;

 

(4) Inner seat ring peeling and cracking;

 

(5) Outer seat ring peeling and cracking;

 

(6) Bearing raceway and rolling body produce indentation.

 

2. Failure cause analysis:

 

Careless inspection before assembly. Bearing should be cleaned and carefully checked before assembly of bearing inner and outer seat ring, rolling body and cage, whether there is rust, burr, bump and crack; Check whether the bearing clearance is appropriate. Whether the rotation is light and free, whether there is a sudden stop phenomenon; At the same time check the diameter and bearing seat hole size, roundness and cylindricity and its surface whether there are burr or four convex inequality. For the open bearing seat, the bearing cover and bearing base joint surface and the outer circle of the outer seat ring, should be set aside between 0.1mm~0.25mm gap, in order to prevent the outer seat on both sides of the "tile" at the "clamp" phenomenon caused by the gap reduction, wear accelerated, so that the bearing premature damage.

 

The inner hole of bearing and shaft are matched with the base hole system, and the outer circle of bearing and the bearing seat hole are matched with the base shaft system. Generally working under normal load conditions of centrifugal pump, centrifuge, reducer, motor and centrifugal compressor shaft and bearing inner ring, using J5, JS5, JS6, K5, K6, M6 match, bearing seat hole and bearing outer ring with J6, J7 match. The rotating seat ring (the inner seat ring of most bearings is a rotating seat ring, the outer seat ring is not a rotating seat ring, and a few bearings are the opposite), usually using interference fit, can avoid rolling and sliding of the seat ring on the matching surface of the bearing diameter and bearing seat hole under load