Determination of Gear and Bearing Material Scuffing Limits Using High-Speed Disk Machines

Abstract

The paper describes the design of disk machines which are used to simulate the contact and scuffing conditions in high-speed aerospace gears and rolling contact bearings. In ground gears the surface finish of the teeth is predominantly in the direction perpendicular to that in which rolling and sliding takes place, and in order to reproduce this configuration in disk tests it is necessary to axially grind the specimens. This has been achieved using a novel grinding/generating process which also gives a self-aligning crowned geometry, thus avoiding spurious edge effects. In the case of rolling element bearings, surface finish is generally of a much higher quality with finish predominantly in the rolling direction. The disk machine developed for simulation of this type of contact therefore uses honed/polished surfaces. Results obtained from the disk machines are shown corresponding to typical high-speed/high-temperature conditions found in aerospace practice.