Analysis of Bearing Failure Causes
Rolling bearings are widely used in the drive system of new energy vehicles, and are one of the parts with high failure frequency. There are many reasons for failure. Among them, the common failure reasons in high-speed bearings of new energy vehicles are as follows:
(1) The material strength of the bearing itself is not enough, the structure is unreasonable, etc., which cause the failure when the car is working.
(2) The long-term high-speed operation of the motor drive system of the automobile causes the bearing wear and fatigue spalling, and the local damage of the rotating body.
(3) Failures caused by improper installation and maintenance, such as bearing alignment errors and ring stress, during the automobile manufacturing process.
(4) Bearing failure caused by moisture and foreign matter intrusion and corrosion during the driving process of the car.
Common failure forms of bearings
Bearings are precision components, and even tiny particles entering the bearing may shorten its service life. Improper lubrication and improper assembly may accelerate early bearing failure.
As far as high-speed bearings in new energy vehicles are concerned, extreme weather such as high and low temperature or heavy rain and snow is often encountered, and complex road conditions such as muddy dirt roads or dusty roads are often encountered.
Therefore, the failure forms of high-speed bearings in new energy vehicles mainly include cage damage, indentation failure, fatigue failure, fracture failure, wear failure, and corrosion failure.
Eigenfrequencies of faults
When there is a local failure in the rolling elements and inner and outer rings of the bearing, a corresponding pulse signal will appear.
The vibration of rolling bearings can be divided into two categories. One is the natural vibration of the rolling bearing; the other is the abnormal vibration of the rolling bearing, which is related to the surface state of the bearing.
Rolling bearing failures can be diagnosed by analyzing abnormal vibrations, including time-domain and frequency-domain amplitudes. The frequency of abnormal vibration is also called the frequency of rolling elements passing through the fault point, which is determined according to the location of the fault.
