Research on the Detection Principle and Measurement Method of Crown Worm Tooth Surface Errors

To test complex helical cylindrical worm tooth surface error, a kind of error detection method is put forward and drum gear surface deviations are regarded as overall judgment of the tooth surface machining error for planar enveloping cylindrical worm. As for the crown worm tooth surface, the mathematical model of tooth surface is established, and the contour scan of test center gear is utilized to obtain axial tooth shape. In order to work out the position of the cylindrical worm tooth surface, the probe radius is compensated based on the cylindrical worm gear tooth surface equation and the characteristics of the gear measuring center. Coordinate transformation is performed to compare contour profile of worm gear tooth surface measured with the drum head center trajectory. LMS principle is adopted to optimize the model parameters and the tooth surface deviation is obtained. The crown worm prototype was used in experiment and the correctness and validity of this measurement method were proved. The results show that the tooth surface error of upside is equal to 0.079 mm, as well as that of the underside is equal to 0.082 mm. The error measurement and evaluation system are formed, and it is propitious to the promotion and application of internal gear enveloping crown worm drive.