Talk about bearing and motor performance

Motor Bearing Function

       (1) supporting the rotation of the motor rotor to transmit load and maintain the rotation accuracy of the motor axis;

       (2) Reduce the friction and wear between the stator and rotor bearings.


Motor bearing code and classification

Deep groove ball bearing example: 6213-2Z/C3Z2 Both sides of the vibration value with iron cover seal is deep groove ball bearing with group C2 clearance in group Z2; acceleration vibration value: Z1; Z2; Z3; Z4. The lower the value, the lower the bearing clearance number: C1; C2 (CN); C3; C4; C5. The original bearing clearance increases sequentially; V1; V2; V3;

Angular contact ball bearings Example: 7315AC Angular contact ball bearings with 25° contact angle (used mostly for vertical motors).

Cylindrical Roller Bearings Example: NU328EM/C3Z1 Brass Cage Inner Ring No Cylindrical Short Cylindrical Roller Bearings. C3 group clearance, Z1 group vibration value.


Bearing clearance

(1) Original clearance: The clearance before the bearing is not installed.

(2) Installation clearance: The clearance after installation of the bearing. Due to the interference fit, the installation clearance is less than the original clearance.

(3) Work clearance: Under normal circumstances, the working clearance is always greater than the installation clearance. In order to obtain a satisfactory performance, the most important thing is to select a suitable working clearance, and the bearing will operate in a near-free state under working conditions, and the best results will be obtained.

Selection of motor bearing clearance

Under normal circumstances, the motor should try to select the normal group clearance. One of the following three factors cannot be met. Try to choose bearings with C3 clearance.

   1. The tolerance of the bearing and the shaft and the bearing seat is very tight, and the amount of interference is too large;

   2. The operating temperature of the motor exceeds 60 degrees;

   3. The speed exceeds 2/3 of the reference limit speed of this type of bearing.