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. Gears are used under severe conditions and are often utilized for applications that demand high speeds and a high load torque. Under such conditions, scoring causes damage to the tooth surface. As a countermeasure against scoring, researchers have focused on various parameters such as the type of lubricant, material, and tooth profile. However, since the instantaneous temperature of the tooth surface significantly affects the scoring load, it is necessary to consider the scoring limit value. A method that considers the tooth surface temperature as a single index has attracted considerable attention.

In recent years, advances in infrared sensors and sensor output signal processing technology have improved the resolution and spatial resolution of temperature measurement. As a result, infrared thermography that is capable of real-time and high-response measurement has been developed. Against the background of this development of infrared image measurement technology, previous research has used infrared thermography technology to evaluate the meshing state of the hypoid gear during actual driving and developed a new tooth contact monitoring method that replaces the conventional method.

In these studies, the rise in the temperature of the contact surface during driving was acquired by thermography, and the contact state was estimated by analyzing the temperature distribution. Hypoid gear pairs are widely used as the final reduction gear for automobiles owing to the following advantages: they can be installed more securely than general spiral bevel gear pairs, the shaft diameter can be increased by increasing the torsion angle of the pinion gear, they have a higher reduction ratio than bevel gear pairs, and they reduce noise.

However, it is well-known that the hypoid gear leads to an increase in the friction loss of the tooth surface owing to the offset. This causes the temperature of the contact surface to rise and the transmission efficiency to decrease. In recent years, with the increasing demand for lower fuel consumption in the automotive industry, there has been a growing demand for achieving higher efficiency while maintaining the advantages of conventional hypoid gears such as high strength and low noise. \[6\] For this reason, various studies have been conducted on hypoid gears; however, only a few of them have focused on the offset of hypoid gears.

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.


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

Division / Sponsors: 
Design Engineering Division and Computers & Information In Engineering Division


Paper Proceedings: https://asmedigitalcollection.asme.org/IDETC-CIE/IDETC-CIE2020/volume/83907

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