Investigation of Tooth Surface Temperature Based on High-Speed Thermography Monitoring Under Meshing of Hypoid Gear With Small Number of Teeth

Improving the noise vibration harshness (NVH) characteristics of systems has recently become a critical issue for meeting user needs in the automotive industry. Note that the accuracy of the tooth surface significantly influences the vibrations of gear meshing. The hypoid gear used in the automobile differential has a complex shape; hence, estimating its contact conditions is difficult. Therefore, we aim to develop a novel method to analyze the tooth contact conditions using highly sensitive infrared thermography measurements with a high response. The proposed method provides a noncontact analysis based on monitoring the temperature distribution during meshing between the pinion and gear surfaces. In this study, we designed three hypoid gear types with high-reduction ratios. Subsequently, a tooth contact analysis was conducted using thermography measurements. As a result, the relationship between the temperature increase at the tooth contact area was clarified.