Powder metallurgy bearing is made by pressing, sintering, shaping and oil-immersing metal powder and other anti-friction materials. It has a porous structure. After being soaked in hot oil, the pores are filled with lubricating oil. The journal rotates during operation. The suction effect and friction heating of the metal and oil heat the metal and the oil to squeeze the oil out of the pores, and then the friction surface acts as a lubrication. After the bearing is cooled, the oil is sucked back into the pores. So what are the common problems in the use of powder metallurgy bearings?
1. Fretting wear on the back of the tile: Spectral analysis found that the iron concentration is abnormal, there are many sub-micron wear particles of iron in the iron spectrum, and the moisture and acid value of the lubricating oil are abnormal.
2. Surface strain: cutting abrasive particles are found in the iron spectrum, and the abrasive particles are composed of non-ferrous metals.
3. Iron-based powder metallurgy bearing journal surface strain: there are iron-based cutting abrasive particles or black oxide particles in the iron spectrum, and there is a tempering color on the metal surface.
4. Corrosion of tile surface: Spectral analysis found that the concentration of non-ferrous metal elements is abnormal; there are many sub-micron wear particles of non-ferrous metal components in the iron spectrum; the moisture of lubricating oil exceeds the standard, and the acid value exceeds the standard.
5. Surface corrosion of powder metallurgy bearing journal: Spectral analysis found that the concentration of iron is abnormal. There are many sub-micron particles of iron in the iron spectrum, and the moisture or acid value of lubricating oil exceeds the standard.
Powder metallurgy bearings are high-precision products. Improper installation can easily damage the bearing raceway and cause damage to the bearing. The bearing should be installed with a special mold, which can not be hit at will. When it is pressed into the shaft, only a small circle can be forced, and when a large circle is pressed, only a large circle can be forced. It is required to use air pressure or hydraulic pressure during installation, and the upper and lower molds should be outside the horizontal state during press-fitting. If there is any skew, the bearing channel will be damaged due to the force, which will cause the bearing to cause noise.