Analysis and Improvement of medium-motor bearing failures
1, the end cap bearing type: Most of these motors there bush fever and leakage phenomenon, resulting in corrosion of the stator coil, and the interior of the motor oil and fouling too much, resulting in a poorly ventilated, so motor overheating and damage.
2, box-type high-voltage motors: The motor is a new type of electric motor production in China in recent years, their performance, appearance are superior to the "JS Series" motor. However, some manufacturers produced such motors, due to the design of the bearing on the existence of certain deficiencies, resulting in more motor running bearing failure occurred. The structure of these motors are mounted on the outside of the bearing of a small gap from the bearing block oil pan, so look inside the bearing grease can maintain adequate, but this structure there are several drawbacks:
(1), is not conducive to the circulation cooling and bearing grease, the bearing temperature during operation, reducing the performance of the grease, and then the temperature rises again causing a vicious cycle, the bearing damage.
(2), due to the presence of the bearing block oil pan, so that the small motor repair, open the bearing cap can not be checked at the time of the motor overhaul, does not remove the block oil pan also check the bearing can not be cleaned, only replaced, unnecessarily waste.
(3), due to be torn down when many of the maintenance and replacement of the bearing block oil pan, resulting in a block oil pan with the hole and shaft loose, so block oil pan in the operation emerge from the shaft, resulting in failure.
3, double bearing motor: part of the production of medium-sized electric motor now, load side uses a dual bearing structure. Although this increases the load carrying capacity of radial side, but also to overhaul brought difficulty. When the motor overhaul, the bearings can not be cleaned and examined and must be replaced, or can not ensure the maintenance of quality, resulting in an increase in maintenance costs. Further, the motor of this structure, most of the bearing in the relatively high temperature operation, reduced service life of the bearing damage.
4. Bearing Accessories structural problem: the majority of China's motor bearing current annex is inner and outer oil cap structure adopted. The disadvantage of this structure is poor sealing effect, the motor, easily inhaled dust from the outside to the inside of the bearing, accelerated bearing wear and damage; another is the structure of their bearing attachments bearing heat, cooling and circulating basic grease does not work, so the higher operating temperature of the bearing, lower life expectancy, resulting in less than an overhaul of the motor cycle bearing that is damaged. According to our analysis we found that imports of medium-sized motor structure, one on either side of the bearing seal all installed devices to ensure a clean inside the bearing; the second is positioned outside of the bearing is provided with cooling means, and oil bearing compartment space than large, thereby greatly reducing the bearing operating temperature, and get good lubrication, extending bearing life.
5, bearing selection problem: According to our analysis and calculation of the motor bearings believe that the choice of bearing failure and the bearing has a great relationship. From the comparison of the motor and the motor imports, the domestic medium-load side of the motor bearing, is generally the choice of "medium-sized roller bearings." Radial load carrying capacity of the bearing is much higher than the calculated value, but allows the motor speed is very little difference between the actual speed, resulting in a less than the rated life of the bearing. But imports of medium-load side of the motor bearings are generally larger selection of "light ball", and the no-load side is chosen smaller than the load side "light roller bearings", it will not only ensure that the carrying capacity of the bearing, and bearing permissible speeds much higher than the actual motor speed, we are able to meet or exceed the bearing life.
