In the planetary reducer, the shaft gear is an important part and an important basis for the stable operation of the reducer. The machining accuracy of the shaft gear directly affects the quality of the reducer. Since the grinding accuracy is closely related to the hobbing accuracy, only by controlling the hobbing error term can gear processing achieve higher quality.
Hobbing precision
Because the accuracy of shaft teeth is generally determined by factors such as ring gear diameter runout, base joint deviation, and common normal length. Therefore, once these factors deviate, the hobbing accuracy will be seriously affected, so what are the determinants of the hobbing accuracy of the planetary reducer?
1. Motion eccentricity: motion eccentricity generally manifests as the length error of the common normal line. The reason for the error problem of this method is that we generally use the generative method in the process of analyzing the gear hobbing. Therefore, when the gap between the tooth blanks is When establishing the tooth-to-tool transmission chain, the transmission ratio relationship must be taken as the main determinant of its kinematics. However, the transmission chain itself is not a single asset structure, it is composed of more transmission components. Therefore, when the transmission chain is in the process of transmission, it will inevitably lead to the situation that some part errors are concentrated at the end of the transmission chain, that is, the inhomogeneity in the transmission of enterprise relativism, and thus have a serious impact on the precision requirements of processing technology . Here, the movement eccentricity, that is, the change of the length of the common normal line, has a certain relationship with the basic condition of the distribution of gear teeth. When the distribution of gear teeth is uneven, the change cost of the length of the common normal line will show its appearance more intuitively. Large working range for various errors.
2. Geometric eccentricity: Geometric eccentricity mainly refers to the radial runout error of the ring gear. The radial runout of the ring gear mainly refers to the gear within the range of one revolution. in the alveolar. Large variations of the probe relative to the gear tooth axis will occur, i.e. eccentricity of the ring gear relative to the shaft axis, known as geometric eccentricity.
3. Tooth profile error: Tooth profile error mainly refers to the distance between the ideal tooth profile method including the actual tooth profile and the working part of the tooth profile. Generally speaking, there is always a certain deviation in the involute tooth profile, which will affect the stability of the transmission, resulting in asymmetry, angle errors, etc., resulting in hob tooth profile errors. However, a specific analysis of the tooth shape error shows that the gear base circle is the decisive parameter in the process of determining the involute tooth shape. Therefore, once there is an error in the base circle, the tooth shape will also produce errors. During gear machining, gear indexing is an important means to ensure the involute tooth profile, which depends on the constant speed ratio between the gear blank hobs, resulting in asymmetry and other phenomena.
4. Tooth direction error: Tooth direction error can only occur within a specific range. It occurs over the full tooth width and above the indexing cylinder. It includes the face distance of the two design flank lines.
5. Roughness analysis: Roughness requirements are generally divided into several phenomena such as analyzing fish scales, teeth gnawing, and tearing.