At present, there are many methods to modify spur gears. The main methods include tooth profile modification and tooth direction modification, with emphasis on tooth direction modification.
(1) The tooth profile modification of spur gear modifies the involute tooth profile before the spur gear to the area near the fillet of the tooth top or tooth root. The seed feeding method can improve the contact state of spur gear tooth surface and prevent the scuffing failure of spur gear.
(2) The tooth direction modification of spur gear means that the direction of modification is the tooth direction. The method of modification is suitable for fine adjustment. The purpose of modification is to make the theory inconsistent with the practice and break the normal stress mode. The load on the contact line of spur gear can be evenly distributed by tooth direction modification. The most widely used shaping methods are: tooth end thinning, spiral angle trimming, drum trimming, etc.