Tooth contact analysis and manufacturing of dual lead worm gears in ISO type I

Abstract

In this paper, the tooth contact pattern and transmission errors of dual lead worm gears in ISO type I are analyzed using tooth contact analysis (TCA) and the worm gears are manufactured. The setting of the hobbing machine for worm wheel manufacturing and the amounts of modification in profile and lead directions of worm grinding machine for worm manufacturing are determined so that the expected meshing conditions can be obtained based on TCA results. The dual lead worm gears in ISO type I were designed and manufactured based on this method, and the actual tooth contact patterns and transmission errors were compared with analyzed ones. Compering with TCA results, actual tooth contact patters were similar to TCA results for both flanks. However, the measured transmission errors were slightly larger than TCA results. After manufacturing worm gears, the profile errors of a worm hob cutter for tool were measured using a gear measuring machine and these measured results were fed back to TCA results in order to improve the accuracy of TCA. The influence of the tooth profile errors of the hob cutter was investigated. TCA results with feedback of tooth profile errors of the hob cutter were closer to the actual transmission errors than TCA results without feedback. As a result, the validity of this method was confirmed.

Keywords

• dual lead
• worm gears
• tooth contact analysis
• manufacturing
• tooth contact pattern
• transmission error