Impact of angular contact ball bearings on use

The shaft parts of the machine tool, especially the main shaft, are generally assembled into a thrust ball bearing and rotate at a high speed, sometimes generating high heat. If this phenomenon is not ruled out in time, it will cause angular contact ball bearings to overheat and increase the temperature of the corresponding parts of the machine tool, resulting in thermal deformation. In severe cases, the spindle and tailstock will be unequal in height, which not only affects the accuracy of the machine tool itself and processing , And will burn the bearings.
The rated fatigue life refers to the total number of revolutions in which a group of bearings of the same model are operated under the same conditions, and 90% of angular contact ball bearings do not exhibit spalling caused by rolling fatigue. When the speed is constant, the total operating time is often used to indicate the rated fatigue life.
When studying the life of thrust ball bearings, we must not only consider the fatigue life, but also consider the several use limits based on the performance of the bearing. For example, the grease life of grease lubricated bearings. Noise life, wear life, etc., vary according to the use limit, and therefore the empirical limit is often selected in advance.
Therefore, it is difficult to know the true cause of the damage by investigating only the angular contact ball bearing damage. However, if you know the use of thrust ball bearings, the conditions of use, the structure around the bearings, and the situation before and after the accident, combined with the damage status of the bearing and several reasons, you can prevent similar accidents from happening again.
The judgment of the availability of angular contact ball bearings is mainly determined by considering the degree of bearing damage, mechanical properties, importance, operating conditions, and the period between the next maintenance. If it has the following defects, it can no longer be used. It must be replaced with a new thrust ball bearing. There are cracks or gaps in any of the inner ring, outer ring, rolling element, and cage.
Wear failure is one of the common failure modes of various types of bearings. According to the form of wear, it can be divided into the most common abrasive wear and adhesive wear.
1. Oil film resistance diagnosis technology
Features: The same evaluation standard can be used for different working conditions. The diagnosis of surface peeling, indentation, cracks and other abnormalities is poor.
Application: Suitable for occasions where the rotating shaft is exposed.
2. Vibration diagnosis technology
Features: Vibration diagnosis technology is widely used; online monitoring can be realized; diagnosis is fast, and the diagnosis theory is mature.
Application: Particularly suitable for fault monitoring of angular contact ball bearings in rotating machinery.
3. Ferrographic diagnostic technology
Features: the machine does not need to be disassembled; low investment and good effect; early fatigue failure of oil-free bearings can be found; wear mechanism research can be done.
Scope of application: It is suitable for the fault diagnosis of angular contact ball bearings lubricated with lubricating oil. It is more difficult for bearings lubricated with grease.
4. Temperature diagnosis technology
Features: simple diagnosis; better judgment of bearing burns.
Application: Simple and routine diagnosis of bearings in machines.
5. Optical fiber monitoring and diagnosis technology
Features: The optical fiber displacement sensor has high sensitivity; the signal is directly extracted from the surface of the oil-free bearing, which improves the signal-to-noise ratio; it can directly reflect the manufacturing quality, surface wear, load, lubrication and clearance of angular contact ball bearings.
Application: Suitable for machines where the sensor can be mounted in a bearing housing.
6. Acoustic emission diagnostic technology
Features: fast and easy diagnosis; online monitoring.
Scope of application: New technologies developed in recent years have rarely been used in bearing condition monitoring.
When taking oil-free bearings directly with your hands, you should fully wash the sweat from your hands and apply high-quality mineral oil before handling. Pay special attention to rust prevention in the rainy season and summer. Under certain special operating conditions, angular contact ball bearings can achieve a longer life than traditional calculations, especially under light loads. These special operating conditions are when the rolling surfaces (tracks and rolling elements) are effectively separated by a lubricating oil film and the surface damage caused by contaminants is limited. In fact, under ideal conditions, the so-called permanent bearing life is possible
Strong punching is not allowed. It is not allowed to strike the bearing directly with a hammer. It is not allowed to transmit pressure through the rolling elements.
As the angular contact ball bearing rotates, the raceway surfaces of the inner and outer rings are in rolling contact with the rolling elements, so the running track is dark. It is not abnormal to attach the running track to the raceway surface. Load conditions, so when disassembling oil-free bearings, pay close attention to and observe the running track of the raceway surface.

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