Tooth Meshing Estimation Based on Monitoring Rotational Vibration and Infrared Thermography Image of Hypoid Gear

Nowadays, the improvement in Noise Vibration Harshness (NVH) is one of the most important issues for meeting the needs of the user in the automobile industry. It is well-known that the tooth surface accuracy significantly influences the vibration in gear meshing. The hypoid gear used in the automobile differential has a complex shape, and estimation of the contact conditions is difficult. Therefore, we attempt to develop a novel method to analyze the tooth contact conditions by using highly sensitive infrared thermography with a high response; this method acts as a noncontact analysis that is based on monitoring the temperature distribution during meshing between the pinion and the gear surface. In this report, we designed three types of hypoid gears with different offsets to observe changes in the meshing phenomenon, which occurred due to the differences in the offset. Moreover, by employing accelerometers during a driving test, the dynamic behavior was also examined. Simultaneously, a tooth contact analysis was carried out using thermography. Consequently, the relationship between the rise in temperature at the tooth contact area and the tendency of the rotational vibration was elucidated.