Gear Downsizing Through the Combined Effect of Load and Residual Stresses: A FEM-based Approach

The advent of mobility electrification is driving the search for gears with high load carrying capacity. In this context, the residual stress state can be used to increase the permissible stresses, thereby enhancing the load-carrying capacity, without increasing the component’s dimensions. To achieve this, the simulation of the residual stresses induced by manufacturing represents a decisive tool in the designing process. Therefore, this investigation’s objective is the development of a strategy of coupling residual and load stresses in the design phase, orienting the design to reduce the gear’s dimensions. The approach involved finite elements simulations of shot peening in the tooth root of a gear. The shot peening was simulated with distinct parameters configurations, inducing distinct residual stress profiles. The load stresses were then coupled with the manufacturing-induced residual stress state, and the equivalent stresses were assessed with the Dang Van fatigue criterion. It was estimated that a reduction of 10% in the teeth width is viable through the induction of an optimized residual stress state without altering the gear bending fatigue life. To verify the simulated results, gear bending fatigue tests were performed. The results reinforce the potential for dimensional reduction by integrating residual stresses with actuation stresses.