A mechanism-based characterization of the load-independent power loss of dip-lubricated gears

In gearboxes, the transmission of power and motion is accompanied by power losses. Load-independent power losses are particularly relevant at higher circumferential speeds. In the literature, load-independent power losses are classified according to their phenomenological characteristics. The identified types of interaction include churning, windage, squeezing, and impulse. This work employs an experimental and numerical investigation of a dip-lubricated gearbox to characterize the physical mechanisms of load-independent power loss. The gearbox oil flow, the wetting of the gear surface, and pressure and viscous forces acting on the gear surface are investigated and linked to each other. In this manner, the interaction types, churning, windage, and their transitions, are classified based on their physical characteristics.