Research on tooth surface of enveloping hourglass worm with variable tooth thickness involute gear

In variable tooth thickness involute gear enveloping hourglass worm gearing, the worm gear is variable tooth thickness involute gear with different helix angles. Based on the equivalent characteristics of axial movement and circumferential rotation of involute helicoid, the axial movement of variable tooth thickness involute gear can realize the accurate adjustment of tooth surface clearance.

At the end of 1960s, Dresden University of technology proposed the involute enveloping hourglass worm drive. Maki and Okamoto of Japan made a detailed discussion on its macro and micro meshing performance, which proved that TI worm drive has the characteristics of multi tooth meshing and high load-bearing capacity. Zhu Jingzi and others made a systematic analysis on the principle and method of tooth surface modification of involute gear, and through comparing the performance data of transmission pair prototype in two cases of modification and unmodified, it is proved that modification can improve the performance of transmission pair. Sun Yuehai et al. And Zhan Dongan et al. Have systematically studied the envelope theory, tooth surface grinding principle, machining and assembly error of TI worm drive, and mastered the key machining technology of TI worm drive.

The left and right tooth surfaces of the involute gear studied above are the same, and the processing method is also relatively mature. However, due to the unequal helix angle between the left and right of the involute gear, the tooth surface of enveloping hourglass worm belongs to the complex spatial helix surface with variable tooth shape, tooth thickness and pitch, which is difficult to be precisely processed by the existing processing technology, Detection methods and instruments can not be directly detected. The transmission accuracy, backlash and transmission performance of transmission pair are closely related to the tooth surface accuracy of enveloping hourglass worm. This paper explores the precision milling process of variable tooth thickness involute gear enveloping hourglass worm tooth surface, puts forward the detection method of enveloping hourglass worm tooth surface error topological map, analyzes the hourglass worm tooth surface detection and data processing method based on gear measurement center, develops hourglass worm sample, and carries out tooth surface accuracy detection.