If the grinding wheel does not work according to the grinding instructions, the surface quality of the bearing will be affected during the grinding operation.
During precision grinding of bearings, due to the high requirements for roughness, the grinding marks on the working surface can often be observed with the naked eye. The surface grinding marks mainly include the following.
The cross helix trace appears. The reason for this trace is mainly due to the poor flatness of the bus of the grinding wheel and the concave convex phenomenon. During grinding, the grinding wheel is only in partial contact with the workpiece. Causes and Countermeasures of Grinding Defects on Bearing Surface
After the workpiece or grinding wheel moves back and forth for several times, the cross helix will reappear in the workpiece and can be observed by the naked eye. The pitch of these spiral lines is related to the speed of the worktable and the rotating speed of the worktable. At the same time, it is also related to the non parallelism of the axis line of the grinding wheel and the guide rail of the worktable.
1. The grinding wheel is poorly trimmed, the edges and corners are not chamfered, and the coolant is not used for trimming;Grinding Defects on Bearing Surface
2. There is too much lubricating oil in the guide rail of the workbench, causing the workbench to float;Grinding Defects on Bearing Surface
3. Poor accuracy of machine tool;
4. Excessive grinding pressure, etc.
（2） There are reasons for the formation of helix
1. The rigidity of V-shaped guide rail is not good. When grinding, the grinding wheel is offset, but the edge of the grinding wheel is in contact with the working surface;
2. When trimming noisy wheels, the reversing speed of the worktable is unstable and the precision is not high, so that the trimming of one edge of the grinding wheel is slightly less;Grinding Defects on Bearing Surface
3. The rigidity of the workpiece itself is poor;Grinding Defects on Bearing Surface
4. There are broken and peeling sand particles on the grinding wheel and iron filings under the grinding of the workpiece accumulated on the surface of the grinding wheel. Therefore, the trimmed grinding wheel should be washed or brushed with cooling water;
5. The grinding wheel is not well trimmed, with local bulges, etc.Grinding Defects on Bearing Surface
The lubrication methods of bearings are grease lubrication and oil lubrication respectively. In order to make the bearing function well, first of all, choose the lubrication method suitable for the use conditions and purposes.
If only lubrication is considered, the lubricity of oil lubrication is dominant. However, grease lubrication has the advantage of simplifying the structure around the bearing.
2. Lubrication methods and advantages and disadvantages
The lubrication methods of rolling bearings are grease lubrication and oil lubrication respectively.
In order to make the rolling bearing function well, first of all, we should choose the lubrication method suitable for the use conditions and purposes. If only lubrication is considered, the lubricity of oil lubrication is dominant. However, grease lubrication has the advantage of simplifying the structure around the bearing.
When disassembling the lower rolling bearing for maintenance, first record the appearance of the rolling bearing, confirm the residual amount of lubricant, and wash the bearing after sampling the lubricant for inspection. As a cleaning agent, gasoline and kerosene are commonly used.
The cleaning of the removed bearing is divided into coarse cleaning and fine cleaning. Put the metal mesh pad bottom in the container respectively, so that the rolling bearing does not directly contact the dirt of the container.
During rough cleaning, if the rolling bearing rotates with dirt, it will damage the rolling surface of the rolling bearing, which should be paid attention to. In the coarse cleaning oil, use a brush to remove the grease and adhesion. After it is roughly clean, turn to fine cleaning.