Installation of rolling bearing
Inspection of shaft and housing hole Rolling bearing should be rigorously inspected before the installation, such as shaft, housing hole, end cover, etc. The shaft and the housing hole should be tested for overall accuracy. The parts that are not required should be repaired or replaced. Otherwise, assembly is not allowed. Inspection of the shaft to check the eccentricity of the journal, bending and diameter variation (ellipticity) to top the shaft on the top of the lathe, or on a cast iron plate supported by a V-shaped iron, with a dial gauge pointer in contact with the bearing The journal, then slowly rotate the shaft to observe the swing of the dial indicator on the journal. If the shaft rotates once, the pointer only swings in one direction and then returns to the original position. This means that the shaft is eccentric or curved, and the eccentricity and the amount of bending are half of the swing value of the dial indicator; if the shaft rotates for one week, After the sub-table pointer swings twice, it returns to the initial position, indicating the journal ellipse. The difference between the maximum value and the minimum value of the dial gauge pointer index is the ellipticity value. When the eccentricity and curvature of the shaft are greater than the specified value, the shaft should be aligned or milled. The ellipticity value should generally not exceed 1/2 of the journal size tolerance. If it is too large, it should be welded, car, and ground for repair. When testing the surface roughness of the journal, if there are burrs or bumps on the journal, it should be finely smashed and then polished with a fine abrasive cloth. Verify the verticality of the shoulder of the journal and the fillet radius of the shoulder of the shoulder. The verticality of the shoulder is close to the shoulder with a square to make it close, and then the light or sunlight is checked, such as light leakage or no light leakage. The shoulder is vertical. The fillet radius at the root of the shoulder can be verified with a rounded pattern. If the fillet radius is too large, the bearing and the shoulder are not tight, which may cause vibration during use; if the fillet radius is too small, the strength of the shaft is affected. Therefore, the radius of the fillet at the root of the shoulder must be smaller than the radius of the fillet of the inner ring of the bearing. Generally, it should be 1/2 of the radius of the inner ring of the bearing to ensure that the bearing abuts the shoulder.
Verify that the journal size can be verified with a micrometer or dial gauge. When the journal wear is severe, the size is less than the specified fitting requirements, and the bearing inner diameter is loose, the bearing neck should be repaired. There are four general repair methods: inserts. When the journal is thicker (greater than 40mm), the journal can be turned off by 10-15mm, then the prepared sleeve is placed in the hot oil to be heated, and the sleeve is placed on the thin journal of the car by the hot fitting method. The outer diameter of the insert is finished to meet the requirements for matching the inner diameter of the bearing. Weld repair. First, rough the grinding of the journal, and turn it off 0. 3-0. 5mm. Then use gas welding or electric welding to repair the welding. After the welding, the journal car is ground to the specified size on the machine. In order to prevent bending deformation of the shaft during repair welding, a symmetrically balanced re-welding method for reverse deformation can be used for welding. Chrome and low temperature iron plating. When the journal size is worn lightly, or the ruler exceeds the difference after the machining, it can be repaired by first grinding and grinding. Knurling is eye-catching. When the journal size is slightly worn or the machining is slightly out of tolerance, you can use the sample to punch a small number of small holes on the circumference of the journal, increase the size of the journal by the convex super-extension of the edge of the small hole, or use knurling on the lathe. The knife is aligned with the journal knurling to increase the journal size and fit with the bearing for installation. This method can only be used as a temporary emergency measure and should generally not be used.