2022 November the First Week VISTA Technical Knowledge: Improvement of Grinding Process for Inner ring of Ultra light Series Deep Groove Ball Bearings

Key words: deep groove ball bearing; Inner ring; Grinding; workmanship

The ultra light series deep groove ball bearings produced by the company have high noise and poor working stability when used. The analysis shows that it is caused by the large elliptical deformation of the inner ring of the bearing and the excessive form and position tolerance. The fundamental sticking point lies in the original ultra light series bearing inner ring grinding process.

The original processing technology is: rough grinding end face → grinding internal and external diameter → rough grinding raceway → rough grinding internal hole → additional tempering → fine grinding end face → one fine grinding raceway → one fine grinding inner diameter → two fine grinding raceway → two fine grinding inner diameter → final grinding raceway → final grinding inner diameter → super precision raceway.

The main reasons for grinding deformation of workpiece inner diameter are:

(1) ) When machining the inner diameter, the included angle of two supporting points β Improper adjustment may lead to excessive roundness of ferrule;

(2) ) The geometric accuracy of the inner raceway exceeds the standard, resulting in large internal diameter re mapping error;

(3) ) Too large grinding depth is easy to cause inner diameter deformation;

(4) ) When grinding the inner diameter, due to the poor accuracy of the grinding wheel spindle, the shape and position tolerance of the machined parts' inner diameter exceeds the standard;

(5) ) The thickness of the workpiece wall is too thin, and improper manual operation (such as unstable clamping, etc.) may cause deformation of the ferrule.

Through repeated process verification, it is found that the defects of the original process can be remedied by changing the original process of grinding the raceway and the inner diameter of the raceway to the internal and external raceways and the inner diameter of the internal and external raceways, but each has its own shortcomings.

The advantage of grinding the raceway and grinding the inner diameter of the branch raceway is that it can eliminate the duplication error of the machining surface of the positioning surface, and the raceway has high machining accuracy. The disadvantage is that the inner diameters of the raceway of the 3M Z1310A grinder and the MZ2015 grinder need to be processed four times respectively. Because the workpiece wall is thin, it is easy to deform, and because the raceway size is processed according to the flow tolerance, the tolerance range is large (generally ± 0.05 mm), which is easy to cause the shape and position tolerance to exceed the standard.

The advantage of internal and external diameter grinding raceway and internal diameter grinding is that three times of internal and external diameter grinding can be carried out on the centerless grinder M1083, which can unify the internal and external diameter dimension tolerance and serve as the positioning benchmark for grinding raceway and internal diameter processes; Carry out three times of inner diameter grinding on the MZ2015 grinder. The thickness of the ring wall is thicker than that of the inner diameter grinding on the roller path. The deformation probability is small during processing, which ensures the inner diameter dimension accuracy and geometric accuracy of the ring. The disadvantage is that it is easy to produce reflection error when grinding raceways with internal and external diameters on 3M Z1310A grinder.

According to the above analysis and verification, the optimal processing technology is: rough grinding end face → rough grinding inner and outer diameters → rough grinding raceway → rough grinding inner diameter → additional tempering → fine grinding end face → fine grinding inner and outer diameters → fine grinding raceway → fine grinding inner diameter → final grinding inner and outer diameters → final grinding raceway → final grinding inner diameter → super precision raceway.

The improved process simplifies the process route, improves the overall quality of the workpiece, reduces the scrap rate to about 2%, reduces the production cost, shortens the equipment adjustment time before processing, and improves the production efficiency. In particular, the greater the production batch, the more obvious the advantages of the process.

More about VISTA High-quality Deep Groove Ball Bearing：

As a deep groove ball bearing manufacturer, Vista supplies single row deep groove ball bearing, double row deep groove ball bearing for customers. Single row deep groove ball bearing includes: 6000 series deep groove ball bearing, 6200 series deep groove ball bearing, 6300 series deep groove ball bearing, 6400 series deep groove ball bearing, 6700 series deep groove ball bearing, 6800 series deep groove ball bearing, 6900 series deep groove ball bearing, 1600 series deep groove ball bearing.