Determining conditions for bearing fit

- Jul 13, 2017-

When deciding the bearing, it is necessary to consider the nature of the load, the load size, the temperature condition, the rotational precision, the material of shaft and shaft bore, the precision of machining and the thickness, the difficulty of installation and disassembly.
I. Nature and coordination of load
Basically, according to the load direction relative to the bearing inner ring, the outer ring is to the rotation or static to decide to cooperate.
II. Bearing load size and surplus quantity
The effect of the load on the size and interference of the relationship between the load more than the surplus is greater. If the interference between the bearing inner ring and the shaft is set, it is necessary to estimate the amount of interference caused by radial loads.
III. Temperature conditions and changes in interference
The interference of the mating surface is also affected by the temperature difference between the bearing and shaft and shaft bore. For example: steam through the hollow shaft, shaft hole material for light alloy, etc., must consider the difference between temperature and line expansion coefficient. In general, the interference of the inner ring decreases with the increase of the bearing temperature in operation.
IV. SHAFT finishing degree and surplus quantity
The convex part of the surface finish is compressed at the time of coordination, thus the effective interference ratio is compared with the measured surplus effect. Under normal circumstances, the effective interference can be obtained by the formula.
V. Minimum interference and maximum excess surplus
When the action line of the load is rotated relative to the inner ring, the bearing inner ring is installed on the axle to set the interference. Maximum interference is the best less than 1/1000 of the axle neck. The effective interference of the outer ring is different from the material, thickness and shape of the shaft hole, according to the experience.