The angular reliability and longevity of angular contact ball bearings are evenly distributed even under good working conditions. For important equipment, equipment that works under harsh conditions, the angular contact ball bearings installed in it are reliable or not, and how long it can continue to operate. Naturally, it is a problem that the department pays special attention to, and it is often and obviously The economic benefits or the relatively serious accident losses are directly related, so the diagnostic technology naturally becomes a technology development domain that the department pays close attention to.
The fracture site was observed by scanning electron microscopy and found to have the following points:
1. Magnification observation, it can be seen that many fan-shaped patterns appear in the micro-region.
2. There is a fatigue arc before the crack and there are a lot of corrosion pits.
3. Different angles observe the shape of the fan-shaped pattern, and the fan-shaped pattern is formed by the connection of different plane cracks. Observing the crack propagation zone at high magnification, the typical fatigue crack is found. At the low-magnification scan of the crack source, it can be found that the beach pattern surrounds the crack source, and there are a large number of corrosion pits in the crack source region, and some corrosion pits are connected into a line and appear as a muddy pattern. Morphology.
4. Accept the high stress, where the water jacket is in contact with the hot rib of the cylinder liner. The stress at B is small. TIMKEN bearing water jacket work mainly accepts three kinds of stress effects: explosion stress, assembly stress and thermal stress. The large stress of the water jacket is the hoop stress, and its value is about 128 MPa. It is a kind of random anomaly in the ignition of the oil-containing angular contact ball. The abnormal defects of the workpiece and the burning accident often seriously affect the appearance quality and product performance of the workpiece, and even cause the workpiece to be unqualified. Loss of scrap, especially for precision workpieces or important workpiece surfaces with high quality requirements.
5. During the observation in production, it is often not the point contact that the workpiece and the sensor are fired during induction heating, and the noise generated by the angular contact ball bearing is very sensitive. Therefore, in order to adhere to the smooth operation of the angular contact ball bearing, a highly reliable sintered bronze oil bearing is used, and some measures must be taken, such as proper control of the sintering conditions, so that the microstructure of the alloy is a single phase, and corrosion prevention measures can be taken. Another way is to make compressive stress on the surface of the workpiece to offset the tensile stress experienced in the service of the water jacket.
