The outer circles of the front and rear bearings of the grinding head of the surface grinder are conical, and there are only three equally spaced flanges in contact with the inner taper hole of the bearing seat. There are 12 evenly spaced axial grooves on the bearings. When the bearings move axially, the radial clearance between the bearings and the shaft changes; When the bearing tightens, only the internal clearance of the three flanges becomes smaller, and the rest of the parts undergo elastic deformation to form three oil wedges, forming an integral three oil wedge dynamic pressure sliding bearing. The clearance of the bearing is small, the rigidity is good, and its lubrication method is self-priming lubrication. During use, there were occurrences of grinding head holding onto the shaft, vibration, and heating.
1、 Analyze the causes of the malfunction.
2、 Using a combination of scraping and grinding to repair bearings:
1. Install the front and rear bearings to the working position, and grind a cylindrical core shaft with a length of 400mm according to the bearing hole. The degree of grinding should be based on the degree of rotation.
2. Install the front and rear bearings, and grind a cylindrical core shaft with a length of 350mm according to the bearing hole. The degree of fit between the shaft and the bearing inner hole should be such that the stiffness can penetrate.
3. Add lubricating oil and perform air running tests before and after installing the grinding wheel, followed by grinding tests.
3、 Using the method of grinding instead of scraping to repair bearings:
1. A cast iron grinding rod with three 120mm lead forward and reverse spiral grooves is used for overall grinding to ensure the coaxiality of the front and rear bearings.
2. Place the grinding head in a vertical position during grinding.
4、 Precautions during the grinding process:
1. During the grinding process, it is necessary to continuously tighten the front and rear bearings to increase grinding efficiency and ensure the geometric accuracy of the bearings.
2. Clean the excess abrasive at the end of the bearing to prevent the front and rear bearings from having bell mouths.
3. After grinding for a period of time, remove the grinding rod, clean the grinding agent in the grinding rod and the front and rear bearings, check the grinding effect and the wear of the grinding rod. If the grinding rod is damaged, it needs to be repaired to ensure the consistency of the hole diameter of the front and rear bearings.
4. When grinding, try to minimize the amount of abrasive and tighten the front and rear bearings appropriately to ensure the final geometric accuracy of the front and rear bearings.