Novel Monitoring Method of Hypoid Gear Meshing Based on Thermal Network Model and Infrared Thermography Imagery

Abstract

Hypoid gears, used in automobile differentials, have a complex shape; thus, it is difficult to estimate tooth contact conditions. Therefore, a non-contact method of analysis is proposed for determining tooth contact conditions by using high-response thermography to analyze temperature distribution during meshing between the pinion and the gear. High-speed photography was performed using thermography and an extraction line was defined in the obtained thermal images to extract temperature data from them. Furthermore, we constructed a novel model to predict tooth surface temperature distribution during tooth meshing based on a thermal network model that represents the thermal conductivity of an object by a simple RC circuit. In this report, by comparing the temperature changes obtained from the thermal images with the calculated results, we identify the thermal properties of a material from the thermal images, and discuss the effects of parameters such as heat capacity and thermal resistance. The comparison shows that infrared tooth surface imagery is effective in estimating hypoid gear tooth meshing. That is, by using infrared image and a thermal network model, heat conduction in a gear can be considered. It was confirmed that it is possible to predict temperature rise on tooth surfaces due to gear meshing.