Contact Analysis of Tooth Surface in Gear Meshing Based on Infrared Ray Imagery

Abstract

Improving accuracy ofthe gear tooth surface has become an important challenge, because the toothsurface accuracy greatly influences vibration of gears. However, for the spiralbevel gear, the tooth surface accuracy is considered to be very difficult toevaluate because the geometrical theory is difficult. Generally, the managementof tooth surface accuracy has conventionally been substituted by the toothsurface contact evaluation with red lead, which is a kind of paint. However,the results of visual examinations are too subjective. We therefore focused onthe infrared ray imagery to investigate the gear tooth meshing. In this research,a high response infrared thermography was used to estimate the tooth contact ofa hypoid gear under running conditions. Specifically, we looked at the increasein temperature on the tooth surface caused by gear meshing. The results clearlyshowed that the temperature was affected by load, sliding speed between toothsurfaces, and the average peripheral speed of tooth surface. We also proposedan equation that predicts tooth surface temperature rise and showed its utility.Thus, the proposed method effectively evaluates the tooth surface accuracy ofhypoid gear.