Effects of Temperature Fields on Gear Contact Fatigue Performance

Abstract

Temperature fields can alter gear contact fatigue through changes in elastic properties and redistribution of tooth loading. This study examines these competing effects using a parameterized steel spur-gear model with prescribed uniform temperatures and linear gradients across the face width. A constrained thermal-displacement model is coupled to unilateral strip contact, local Hertzian pressure, and an assumed relative fatigue-life relationship. All numerical results are model estimates rather than experimental measurements. Uniform heating from 40 to 80 °C reduces peak contact pressure by approximately 0.8% and increases the pressure-only life indicator to 1.050 times its reference value. At the same mean temperature of 80 °C, end-to-end temperature differences of 10, 20, and 40 K increase peak pressure by approximately 19.3%, 36.5%, and 61.8%, respectively, relative to the reference condition. Corresponding pressure-only life indicators decrease to 0.346, 0.155, and 0.056. An assumed temperature-dependent fatigue-strength reduction further decreases these indicators. Constrained differential expansion therefore dominates the modest pressure reduction associated with elastic softening in the selected scenarios. The magnitude depends on support compliance, displacement transfer, and fatigue calibration; absolute service life cannot be inferred.