① According to the causes of cracks, the process flow of gears was analyzed again. It was found that there was no preliminary heat treatment before heat treatment, and there was no aging process after semi precision grinding after heat treatment. Now, the process flow of this type of gear is optimized and refined, the stabilization treatment is added after rough machining, the semi precision grinding process is added after cyanidation, the gear grinding allowance is decomposed twice, and the aging process is added after gear grinding to eliminate the gear grinding stress.
② In the process of gear grinding, the selection of grinding wheel and machining parameters are not appropriate. Semi precision grinding is processed on the CNC universal grinder S30. The original grinding wheel is replaced with pa100kv chromium corundum grinding wheel for gear grinding. It has good self sharpening and high sharpness. The precision grinding is processed on the CNC universal grinder S21, and the chrome corundum grinding wheel pa120kv is also selected. The gear grinding parameters are also optimized, and the final gear grinding parameters are obtained.
③ Grinding heat is the root cause of gear grinding cracks, so reducing grinding heat is the key to solve gear grinding cracks. The CNC grinder has two groups of cooling oil pipes. During use, one group shall be accurately sprayed on the cutting part of the grinding wheel, and the spraying direction is opposite to the rotation direction of the grinding wheel, so as to ensure that the grinding wheel foam and metal chips adhered to the grinding wheel can be washed out in time, and the other group shall be sprayed on the gear grinding area, and the spraying direction is the same as the rotation direction of the grinding wheel, It is convenient for the cooling oil to reach the gear grinding area through the centrifugal force of the grinding wheel, so as to ensure the sufficient cooling of the gear grinding area.