DLHEnhancing tribological properties of involute gear teeth through discrete hardening treatment using a biased laser source with axis

Traditional methods for enhancing surface fatigue in gears are limited by their techniques and processes, making it increasingly challenging to achieve a balance between strength and toughness and meet the demands for fatigue-resistant manufacturing of high-energy-density gears. In this study, a novel tooth surface laser discrete strengthening method is proposed, focusing on validating the actual effects of laser discrete processing and strengthening on the involute gear tooth surface. Through comprehensive simulations and experiments, the consistency and feasibility of the process within a tilt angle range of 0 to 30° are demonstrated. To address laser interference between adjacent gear teeth, a processing technique is introduced that involves the offsetting of the laser beam from the gear axis and the tilting of the optical path relative to the normal of the tooth profile. By deriving the coordinates of evenly distributed points on the involute gear profile, a strategy for biased discrete hardening processing is formulated. Furthermore, remarkable benefits are revealed through friction experiments conducted on physical gears processed using this technique, including the reduction of friction power (9.36 % to 27.10 %), the stabilization of output torque , and the improvement of substrate protection, thus confirming the effectiveness of this technique in resisting contact fatigue damage. Valuable insights into advancing the field of fatigue-resistant gear manufacturing through the utilization of laser-based discrete hardening techniques are provided by this research.