Bearing impact on the motor
For rotating electric machines, bearings are a key component. The performance and life of the bearing are directly related to the performance and life of the motor. The manufacturing quality and installation quality of the bearing are the key factors to ensure the quality of the motor.
Motor bearing function
(1) Supporting the rotor of the motor to transfer the load and maintaining 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 two sides with iron cover seal vibration value is C3 group deep groove ball bearing; acceleration type vibration value: Z1; Z2; Z3; Z4. The vibration value is getting lower and lower; bearing clearance code: C1; C2 (CN); C3; C4; C5 bearing original clearance increases in turn; V1; V2; V3; vibration velocity level is lower and lower.
Angular contact ball bearing example: 7315AC angular contact ball bearing with a contact angle of 25° (used for vertical motors)
Cylindrical roller bearing example: NU328E / C3Z1 copper cage inner ring without rib flange cylindrical roller bearing. C3 group clearance, Z1 group vibration value
(1) Original clearance: the clearance before the bearing is installed
(2) Installation clearance: The clearance after installation of the bearing is less than the original clearance due to the interference fit relationship.
(3) Work clearance. Under normal circumstances, the working clearance is always greater than the installation clearance. In order to obtain satisfactory working performance, it is important to select a suitable working game. The bearing is running in a state of no play in the working state, and the effect is best.
Motor bearing clearance selection
Normally, the motor should try to choose the normal group clearance. One of the following three factors can not be met, try to choose the C3 clearance bearing.
1. The bearing tolerance of the bearing on the shaft and the bearing housing is very tight, and the interference is too large;
2. The working temperature of the motor exceeds 60 degrees
3. The speed exceeds 2/3 of the reference speed limit of this type of bearing