Premature aging of rolling bearings will cause equipment to stop. Now we combine the author's motor maintenance practice to introduce the experience of preventing premature aging of rolling bearings. The reasons for premature aging of rolling bearings are: too tight, poor lubrication, misalignment, strong vibration, material fatigue, pollution and corrosion.
Tight fit
When the inner ring of the bearing is forcibly inserted into the journal, the lighter will cause a severely worn circular path at the bottom of the raceway, and the heavy one will have cracks or peeling on the inner and outer rings of the slideway and the ball. Reason: The gap between the ball and the slide is too small, the torque is increased, the friction is increased, and the working temperature of the bearing is too high, which causes the
bearing wear and fatigue to deteriorate and fail.
Prevention method: Restore the radial clearance of the bearing and reduce the interference.
There are two ways to check the quality of bearing assembly:
Visual inspection method: When the bearing cover of the motor end cover is mounted on the bearing, when the end cover is rotated by hand, if the
bearing rotates freely and flexibly, there is no vibration and shaking up and down, which is considered qualified.
The feeler gauge method: assemble the motor end cover with the bearing on the frame seat, and check the radial clearance of the bearing with a 0.03mm thick feeler gauge. If the maximum gap position is just above the center (motor horizontal installation) ), the assembly is correct and reliable, otherwise it is poorly installed. The end cap position should be properly adjusted and reassembled until it is qualified.
2. Poor lubrication
The reason is a serious lack of grease or dryness of the grease. Due to the high-speed running friction of the motor, the bearing temperature is too high and oxidative discoloration, which means that the ball, cage, inner ring and journal of the bearing become brown or blue.
Prevention method: According to the running time of the motor, the ambient temperature, the load condition, the quality of the grease, etc., determine the oil replenishment and oil change time. Under normal circumstances, the motor should be replenished once for 6000~10000h; the oil should be changed once for 10000~20000h, and the oil change of the motor with 2 or more poles is 1/2~2/3 of the bearing chamber volume, and High quality lithium grease (code ZL-2) should be used.
