Development of an analytical model to predict the churning power losses of an orthogonal face gear

Abstract

As one of the basic energy dissipations for one orthogonal face gear running partially submerged in an oil bath, there is no open literature concerned on the churning power losses of the face gear. This paper proposed a series of formulas to predict the churning losses for one orthogonal face gear running partially submerged in an oil bath. The analytical model of churning drag forces is based on fluid mechanics and boundary layer theory which enables quantitatively calculating the influences of the rotating speed, fluid attributes, and gear geometric construction with the minimum effort. Then, an ad hoc test bench was set up to carry out the specific splash lubrication tests for single face gear at different rotating speeds and initial immersion depth. Finally, considering both the churning and windage effects, a physical-based model adopting the real-time immersion depth instead of the static immersion depth is developed to calculate the total load-independent losses of a splash lubricated face gear. From this, the theoretical results are compared well with sets of directly measured experimental findings. Meanwhile, the model is also exploited to quantitate the contributions of each part in the total load-independent losses for one face gear under splash lubrication condition.