A Helical Gear Pair Pocketing Power Loss Model

Abstract

A new fluid dynamics model is proposed to predict the power losses due to pocketing of air, oil, or an air-oil mixture in the helical gear meshes. The proposed computational procedure treats a helical gear pair as a combination of a number of narrow face width spur gear segments staggered according to the helix angle and forms a discrete fluid dynamics model of the medium being pocketed in the gear mesh. Continuity and conservation of momentum equations are applied to each coupled control volume filled with a compressible fluid mixture to predict fluid pressure and velocity distributions from which the instantaneous pocketing power loss is calculated. The proposed model is exercised in order to investigate the fluid pressure and velocity distributions in time along with the pocketing power loss as a function of the speed, helix angle, and oil-to-air ratio.