The tooth profile of gear parts obtained through hobbing or gear hobbing often requires precision machining. Grinding is mainly used for precision machining of hardened gears. Due to the ability of gear grinding to correct various errors in gear pre machining, the machining accuracy is relatively high. After grinding, the accuracy can generally reach level 6 or above.

Grinding machining is the precision machining of the tooth profile of hardened gears on a grinding machine. After grinding, the accuracy of the gears can reach level 6 or above. According to the formation method of tooth profile, there are also two types of gear grinding: forming method and expanding method, but most types of gear grinding machines use expanding method to process gears.

Single tooth indexing expansion method editor

Single tooth indexing method

Single tooth indexing method

This type of grinding method can use conical grinding wheel grinding machine, disc-shaped grinding wheel grinding machine, etc. according to the shape of the grinding wheel. Their working principles are the same, both using the meshing principle of racks and gears to grind gear teeth, as shown in the figure. During processing, the gear being cut rolls back and forth once to complete the grinding of one or two tooth surfaces. Therefore, multiple divisions and processing are required to complete the machining of all tooth surfaces.

Disc shaped grinding wheel for gear grinding

The disc-shaped grinding wheel is used to grind the teeth by forming the two tooth sides of the imaginary rack with the end planes of two disc-shaped grinding wheels, as shown in Figure a. At the same time, the left and right tooth surfaces of the tooth groove are ground. During operation, the main motion B1 of the grinding wheel rotates, while the workpiece rotates B31 and moves A32 in a straight line. These two movements of the workpiece are the necessary generating motions to form the involute profile; In order to grind the entire tooth width, the workpiece also needs to undergo axial feed motion A2; after grinding each tooth, the workpiece also needs to be divided.

The machining accuracy of the disc-shaped grinding wheel method is relatively high, mainly due to the narrow working edge of the grinding wheel, small grinding contact area, and low grinding force and heat. The machine tool has an automatic dressing and compensation device for the grinding wheel, which enables the grinding wheel to always maintain sharpness and good working accuracy. Therefore, the grinding accuracy is high, up to level 4, and it is one of the high precision grinding machines among various types. Its disadvantage is that the rigidity of the grinding wheel is poor, and the grinding amount is limited, so the productivity is low.

Cone shaped grinding wheel for gear grinding

The cone grinding wheel grinding method uses the side of a cone grinding wheel to form an imaginary rack with one tooth on the tooth side for grinding gears, as shown in Figure b. During machining, the grinding wheel not only performs the main rotational motion B1, but also performs a longitudinal linear motion A2 to grind the entire tooth width. Its development motion is the same as that of a disc-shaped grinding wheel grinding teeth.

The productivity of a conical grinding wheel is higher than that of a disc-shaped grinding wheel, mainly because the conical grinding wheel has a higher stiffness and can use a larger cutting amount. Its main disadvantage is that the shape of the grinding wheel is difficult to adjust accurately, and the wear is fast and uneven, resulting in lower machining accuracy.