The Cause Of The Operation Failure Caused By The Failure Of The Automobile Hub Bearing

The main task of failure analysis of automobile hub bearing is to find out the main factors which cause the bearing failure according to a large number of background materials, analysis data and failure forms, so as to put forward improvement measures to extend the service life of the self-aligning roller bearing and avoid the sudden early failure of the bearing.

After a period of movement, vibration and noise are maintained at a certain level, and the spectrum is very single, only one or two times frequency. There are few frequency spectrum above three times of power frequency, bearing state is very stable and enters stable working period. After continuing operation, the vibration and noise of the wheel hub bearing of the automobile start to increase, sometimes there are abnormal sounds, but the vibration increases slowly. At this time, the bearing kurtosis value suddenly reaches a certain value. We believe that the bearing is an initial failure at this time. At this time, it is required to monitor the bearing closely and pay close attention to its changes. After that, the bearing kurtosis began to decrease rapidly and close to the normal value. While the vibration and noise began to increase significantly, the increase range began to accelerate. When the vibration exceeded the vibration standard (such as ISO2372 standard), the bearing kurtosis value also began to increase rapidly. When the vibration standard was exceeded, and the kurtosis value exceeded the normal value (the relative standard of available kurtosis), we believe that the bearing has entered the normal value In case of late failure, the equipment shall be repaired and bearings replaced.
The automobile hub bearing shows the late fault characteristics, and the serious failure (generally, bearing damage such as shaft holding, burn, sand frame spalling, raceway, bead wear, etc.) is not more than one week. The larger the equipment capacity, the faster the speed is, the shorter the interval time. Therefore, in the actual bearing fault diagnosis, once the fault characteristics of the late stage are found, it is necessary to determine the bearing fault and arrange the maintenance as soon as possible.
1. Drilling, groove, chamfering and end face of the vehicle are not allowed on the bearing during installation. Otherwise, it is easy to cause deformation of bearing ring, affect bearing precision and life. At the same time, the metal cut out easily enters the working surface of bearing, accelerates the wear of raceway and rolling body, and causes premature damage to the bearing.
2. It is not allowed to directly knock the bearing ring with a hammer during installation. The reference end face of the bearing is installed facing inward against the shoulder. The reference end face of the bearing is distinguished according to whether there is typing on the end face of the automobile hub bearing. The deep groove ball bearing, the center adjusting ball bearing, the cylindrical roller bearing, the aligning roller bearing and the needle roller bearing take the wordless end face as the reference plane; the angular contact ball bearing and the tapered roller bearing take the word end face as the reference plane.
3. During installation, the pressure shall be added to the end face of the ferrule with interference fit, that is, when installed on the shaft, the pressure shall be added to the end face of the bearing inner ring; when installing the bearing seat hole, the pressure shall be added to the end face of the outer ring of the bearing. Transfer pressure is not allowed through rolling bodies and holding.
4. For the bearing with tight fit and sliding fit of outer ring, the bearing which is non separable type shall be installed on the shaft first, and then the shaft and bearing shall be installed in the bearing housing hole; for the separable type, the inner and outer rings can be separately installed.
5. In order to prevent the bearing installation from tilting, the center line of the shaft and bearing hole must coincide during installation. If the installation is not correct, the bearing must be pulled out through the inner ring end face when it needs to be reinstalled.

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