Sometimes the direction and size of the load cannot be determined accurately. For example, in high-speed rotating machinery, in addition to the load bearing the rotor weight is fixed in the direction, there is also the rotating load caused by the unbalanced mass. If the rotating load is much larger than the fixed load, then the resultant load is still the rotating load. If the rotary load is much smaller than the fixed load, the resultant load is the oscillating load. The magnitude and direction of the rotating or swinging load are constantly changing. But in the variable working state, some rings may be subjected to a rotating load, a fixed load, and a swinging load. This load is called an indefinite load.
"creep" phenomenon occurs on the matching surface of its ring on the shaft or in the seat hole. When the load is very light, or when the ring rotates at low speed occasionally under heavy load, the transition fit can be selected. In this case, the shaft surface should have a higher hardness and a smaller surface roughness.