First, analyze the cause of the fault
After analyzing the causes of the failure in the equipment, it was found that the surface of the journal part of the grinding wheel shaft in the surface grinder has longitudinal cracks, and the front and rear bearing appearances have no obvious defects, and the wear amount is not large. The grinding head is dismantled and tested. It was found that the grinding wheel shaft was curved, and only shallow longitudinal cracks were present in the journal portion. The outer cone flanges of the front and rear bearings are in good contact with the bearing housing bores, and there is no obvious damage to the inner bore of the bearing. Therefore, the main reason why the grinding head can not work is that the geometrical accuracy of the front and rear bearings changes, and the shape and size of the three oil wedges are inconsistent. Therefore, the plan to repair the repair is to repair the front and rear bearings and the hard chrome (0.02mm) repaired grinding wheel shaft.
Second, the combination of scraping and grinding to repair the bearing
The bearing is repaired by the combination of scraping and grinding. The front and rear bearings are first shaved, and the contact area is increased by grinding to reduce the surface roughness value. The scraping method is used for scraping and must not be scraped into fish scales.
1. Install the front and rear bearings to the working position, and grind a cylindrical mandrel with a length of 400mm (55mm in diameter) according to the bearing hole. The degree of grinding is subject to the rotation. Apply a thin layer of red dan oil on the mandrel, insert the mandrel into the bearing, adjust the tightness of the front and rear bearings, turn the mandrel, and pull out the mandrel to make a light scratch point. This work must be repeated to achieve uniform density in the three rectangular strip contacts on the front and rear bearing inner surfaces. Then grind a cast iron grinding rod with a diameter of 0.02mm and a length of 400mm which is smaller than the mandrel, and apply W5 chrome oxide paste to grind the front and rear bearings at the same time, tighten the front and rear bearings at any time and pay attention to remove the excess of the bearing end. Abrasives. After grinding, the contact surface of the bearing is a complete three rectangular contact strips, and finally the bearing housing is removed and carefully cleaned so that it does not have any impurities.
2. Install the front and rear bearings in place, and grind a cylindrical mandrel with a length of 350mm according to the bearing hole. The degree of fit with the inner hole of the bearing is suitable for the rigidity to penetrate. Adjust the front and rear bearings until the mandrel is difficult to rotate. During the adjustment process, the front and rear bearings should be alternated. Do not adjust one of them first and then adjust the other. According to the mandrel diameter of 0.01mm, the grinding wheel shaft journal can be assembled after polishing.
3. Fill the lubricating oil in sequence to carry out the dry running test before the loading wheel and after the grinding wheel, and finally carry out the grinding test. After grinding, the front and rear bearings have three long rectangular contact faces with a width of 15 mm corresponding to the outer tapered flange. In order to further reduce the roughness of the bearing bore, we tried to polish it with toothpaste. No significant change was found in the final assembly accuracy of the inspection rods, ie the diameter was subtracted from 0.01 mm as the size of the wheel journal.
For more information and purchase please visit: https://www.supplyforever.com
