Regarding the issue of motor bearings

Regarding the issue of motor bearings

Usually, it is recommended to choose bearings with the same clearance at both ends of the motor.

The selection of clearance for motor bearings is based on the working state of the motor, mainly factors such as temperature, speed, and the fit tolerance between the 

bearing and the shaft and bearing seat.

If the fit tolerance between the bearing, shaft, and bearing seat is not very tight, the working clearance of the bearing does not change much after assembly, the working 

temperature of the motor is below 60 degrees, and the speed does not exceed two-thirds of the reference speed of the bearing model, ordinary clearance bearings can be 

selected.

If any of the above three factors cannot be met, try to choose bearings with C3 clearance.

However, the bearings with C3 clearance will cause slight vibration and noise to the motor during operation, but after working for a period of time and the temperature 

rises, the vibration and noise will slightly decrease.

At present, for the selection of bearings in the domestic motor industry, if extremely special circumstances are not considered, ordinary clearance is usually chosen for 

bearings with an inner diameter of 100 or less, and C3 is considered for bearings with an inner diameter of 100 or more. This choice also makes some sense, because the

larger the size of the bearing, the greater the thermal expansion.

Another reason is that the temperature of the motor itself increases due to other factors such as electromagnetic induction intensity, chip adhesion eddy currents, and 

poor coaxiality of the stator and rotor caused by low precision of machined parts. Therefore, it is recommended to choose bearings with C3 clearance.