Comparison of Involute and Cycloidal Engagement in Harmonic Drives

Harmonic drives with an involute tooth profile have such faults as noise effects, tooth skips, jamming, increased tooth wear, etc. One of the reasons for the appearance of these shortcomings is the interference of the teeth, which can be caused by an incorrect choice of gear parameters, errors in the manufacture and mounting transmission elements. Interference occurs due to small gaps at the entrance to the engagement of the teeth. To increase these gaps, it is proposed to use cycloidal tooth shapes. To determine the minimum clearance at the entrance to the teeth engagement in involute and cycloidal gears theoretical studies have been carried out. It is shown that in the cycloidal engagement the minimum gap at the entrance to the engagement is much larger than in the involute one. The influence of the moment of resistance on the output shaft and the radial displacement of the cam axis on the specified clearance has been studied.

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