Experimental and Analytical Investigation of Surface Wear on Spur Gear

Abstract

As far as automobiles are concerned, gears are normally submerged in lubricant in a closed and controlled temperature environment. A lubricant act as a thin layer between the teeth of the mating gear. During a heavy operation, it controls the tooth contact from the excessive temperature. Further, due to lack of lubricant and high contact tension, pitting occurs at the pitch line of the tooth during the engagement of the gear teeth. Owing to the changes in the direction of the lubricant, the direct metal to metal contact occurs at the pitch line. At this point of time, the approach and recess angle occur in the mating of gear teeth. Here, the gear contact contains simultaneous rolling and sliding force between two mating gear teeth surfaces. Rolling implies an indication that all surfaces would be at the same velocity and there is no differential slip. There is wear whenever there is slip. As a result, pure rolling results in fatigue on the surface. Surface fatigue is the localized material fracture induced by the action of continuous tensile stressing of a substrate from a solid surface. Recurrent compressive load rolling over a layer may cause the material to spill out from the cracking subsurface forming pits or craters. In this context, the non-uniformed tiny slip following a Hertzian contact of different mating gear teeth surface causes a small amount of rolling wear. Despite substantial advancements in computer modelling and analysis in recent decades, the experimental studies are still required to analyze the mechanical components which are prone to wear. The main reason is that gears are one of the most important components in every industry. In the same way, wear studies employing varying torque and speed in a dry or lubricated state are required to predict the life of the gear. When material is removed from the gear profile owing to surface wear, the surface force in the gear profile is rearranged. In this context, the purpose of this study is to use analytical methods to determine the wear depth of unl