For imported bearings, the inner and outer rings can be mounted separately, which simplifies the installation process, especially when the inner and outer rings require an interference fit. When loading a shaft with the inner ring in place into a bearing housing that already contains an outer ring, care must be taken to check that the inner and outer rings are properly centered to avoid scratching the bearing raceways and rolling parts. If the cylindrical and needle bearing are fitted with an inner ring without flange ribs or an inner ring with flanged sides on one side, it is recommended to use a mounting sleeve. The outer diameter of the sleeve shall be equal to the inner ring raceway diameter F, and the tolerance for machining shall be d10. Drawn cup needle roller bearings are preferably mounted using a mandrel. The lubrication of imported bearings is basically the same as that of other rolling bearings. However, the working conditions of imported bearings are relatively harsh, and the effective performance of the working performance depends largely on the lubrication of the bearings.
The lubrication methods used for imported bearings are mainly grease lubrication and oil lubrication. The grease-lubricated grease has a sealing function, the sealing structure and the lubrication facility are simple, and the grease is convenient to be replenished, so the imported bearings are generally grease-lubricated as long as the working conditions permit. The oil lubrication has a strong cooling effect and can remove dirt and moisture from the bearing. The oil-lubricated lubrication methods for imported bearings include pressure oil lubrication, fuel injection lubrication, oil mist lubrication and oil and gas lubrication. Pressure oil lubrication is the most effective lubrication method for imported bearings at normal speed. Injection lubrication is to lubricate the lubricating oil with a certain pressure through the injector mounted on one side of the bearing for lubrication. It is generally used in high-speed imported bearings, or where the pressure supply lubrication cannot meet the cooling requirements. Spray lubrication is to spray dry compressed air containing oil mist into the bearing for lubrication. The amount of oil used is small. Due to the action of air, the cooling effect is extremely strong. It is mainly used for large imported bearings with high rolling speed and high rolling precision. Or for imported bearings that are not frequently removed in the bearing housing. Pressure oil lubrication and fuel injection lubrication need to install inlet and outlet pipes, lubrication pumps, oil reservoirs, and sometimes oil coolers. Therefore, the cost is high, and the imported bearings are generally used less.
Grease is very critical in the process of using imported bearings. The use of a deteriorated grease will cause damage to the bearing. For the inspection of bearing grease, there are the following methods:
Oil droplet trace method
Take a clean white filter paper, drop a few drops of oil on the filter paper. After the oil leaks, if there is black powder on the surface, touch the hand with a feeling of resistance, it means that there are many impurities in the lubricant, good. The lubricating oil has no powder, is dry and smooth by hand, and has a yellow mark.
2. Handcuffs
The lubricant is rubbed repeatedly between the thumb and the index finger. The better lubricant feels lubricated, less wear debris, and no friction. If you feel a large friction between the fingers, it means lubricating oil. There are many impurities inside, can not be reused, should be replaced with new lubricants.
3. Illumination method
On a clear day, use a screwdriver to pry the lubricant at a 45-degree angle to the horizontal. Observe the sunlight and observe the oil droplets. Under the light, it can be clearly seen that there is no wear debris in the lubricating oil, which can continue to work. If the grinding debris is too much, the lubricating oil should be replaced.
4. Oil flow observation method
Take two measuring cups, one of which is filled with the lubricating oil to be inspected, the other is placed on the table, and the measuring cup filled with lubricating oil is lifted off the table 30-40 cm and tilted to allow the lubricating oil to slowly flow to the empty cup. In the middle, observe the flow, the quality of the lubricating oil flow should be slender, even, continuous, if the oil flow suddenly and slowly, and sometimes there is a large flow, then the lubricant has deteriorated.
