Home > Tech > Tapered roller bearing expert: why the bearing burns or locks up

Tapered roller bearing expert: why the bearing burns or locks up

wallpapers Tech 2020-08-20
Why does tapered roller bearing burn or lock
1. Improper selection of bearing clearance.
For example: C3 group clearance should be used, but the normal group clearance is actually used. Because the bearing will continue to accumulate heat when it is working, the shaft diameter, inner ring and rolling elements will expand. The outer ring expands relatively small due to good heat dissipation conditions. In general, the bearing clearance becomes smaller, and even larger negative play occurs. Gap.
At this time, the compressive stress between the rolling element and the raceway increases, the lubrication condition decreases, boundary lubrication phenomenon and even local steel-to-steel dry friction occurs, so the temperature continues to rise, and the base oil in the grease gradually volatilizes. Such a vicious cycle causes the bearing to be overheated and burned, and the rolling elements become blue and black after annealing. At this time, the friction of the bearing increases sharply, the rolling elements stop rotating and squeeze the cage, causing the bearing to lock.
2. The size deviation of the bearing seat hole is too small or the size deviation of the shaft is too large, and the deformation of the squeezed bearing ring makes the clearance smaller. Resulting in burning and seizure phenomenon.
3. There are foreign objects, such as iron filings, burrs, sand particles, cotton thread, etc., between the outer diameter of the bearing and the housing hole or between the inner diameter of the bearing and the shaft surface. It will also squeeze the bearing deformation and reduce the clearance. Resulting in burning and seizure phenomenon.
 
The cause of the accident can be analyzed according to the burning degree of the inner shell, outer shell and roller of the bearing
1. The inner shell is the most burnt, the roller is slightly lighter, and the outer shell is almost unchanged. After excluding the reason for the non-standard size of the inner shell of the inferior bearing, the following judgments can be made. The shaft head tolerance is too small and the shaft head is thin, and there are obvious friction marks between the inner shell and the shaft head. If there are friction marks on one or both sides of the inner shell, it is caused by abnormal contact between the parts that move relative to the inner shell of the bearing and the inner shell of the bearing to generate heat due to friction.
2 The burn marks of the inner and outer shells are not serious, and the rollers are blackened or even deformed. Generally, the tolerance of the inner or outer shell is too large to reduce the bearing clearance, or even negative tolerance, which causes burns. Or the bearing selection is not correct during maintenance, and large clearance bearings can be used.
3 The outer shell is seriously burnt, and there is no obvious change in the inner shell and the roller. You can observe whether the outer shell has friction marks. There are friction marks on the outside. It can be considered that the tolerance of the bearing housing and the shaft seat is insufficient, and the bearing operation is caused by abnormal friction caused by the sliding of the housing. If there are friction marks on one or both sides of the shell, it is caused by abnormal contact between the parts that move relative to the bearing shell and the bearing shell, which is caused by friction and heat.

Say something
  • All comments(0)
    No comment yet. Please say something!
Tag: tapered roll