The radial runout error of gear ring is a common error in gear hobbing. The so-called radial runout deviation refers to the large variation of the measuring head relative to the gear axis when the gear is in the range of one revolution, the measuring head is in the tooth groove, and the high and middle parts of the gear are in contact on both sides. Ring gear diameter runout mainly reflects the effect of geometric eccentricity of gears or installation eccentricity of gear blanks. The measuring method of ring gear diameter runout is similar to the measuring principle and method of cylinder outer circle diameter runout, but the difference is that the measuring head contacts the tooth surface near the gear reference circle;

　　Gear detection - yaw meter

　　The general measuring method of gear processing plants is to use a deflection meter, a needle roller, a dial indicator or a dial indicator; This method is simple and easy to implement, easy to operate, low requirements for operators, and easy to popularize; There are also other special measuring equipment, such as ring gear radial runout tester; Or measure on the tooth measuring instrument.

　　The cause of the gear ring diameter jump out of tolerance is the geometric eccentricity of the gear blank or the installation eccentricity of the gear blank; For the geometric eccentricity of gear blank, the inner hole and the outer circle can be clamped and processed at one time when the gear blank is processed. The accuracy of the machine tool is used to ensure that the axes of the inner hole and the outer circle coincide, so as to solve the problem of geometric eccentricity; For the eccentric installation, it can only improve the skill level and sense of responsibility of the operator. When installing the gear blank, it should be operated correctly and corrected in a timely manner;