Evaluation of the Surface Condition of Spur Gears Using the Acoustic Emission Method

The vibration method is a standard non-destructive inspection method used to identify defects in rotary machines. However, it is difficult to detect defects at an early stage with this method. Therefore, an effective alternative monitoring technique is required to detect defects at an early stage. The acoustic emission (AE) method can be used to determine small defects in a material by detecting elastic waves that occur when cracks or deformations begin to form. In this study, we developed a method to monitor the surface condition of the gear teeth, and examined its relationship with the released AE wave. A correlation was obtained between the RMS value and the average roughness of the gear teeth surface, wherein the RMS value increases with the increase in the surface roughness. However, a large deviation was observed due to the existence of wear particles. Therefore, the effect of wear particles on AE signals was examined. The existence of the particles was estimated by measuring the AE signals of 33-140 kHz, and the approximate teeth surface roughness was estimated by measuring the AE signals of 140-300 kHz.