Analysis of Gear Tooth Performance of Mechanically-Coupled, Outer-Rotor Polysilicon Micromotors

Abstract

This paper focuses on specific design of gear teeth for micromotors, as well as performance evaluation of the coupled micromotors both in air and using different lubricants. Two basic types of gear teeth, as described in Tables 1 and 2, have been studied to evaluate their appropriateness for mechanical coupling of outer-rotor micromotors: involute shaped teeth and cycloidal shaped teeth. These tooth profiles have been chosen since the contact between teeth of mating gears has pure rolling motion at the pitch line (involute shaped teeth) or pitch circle (cycloidal shaped teeth) [1]. Figure I shows SEM photos of two pairs of coupled 75 µm micromotors, and Figure 2 shows SEM photos of typical involute and cycloidal gear teeth after fabrication and release.