Study on the Lubrication Characteristics of Spur Gear Pairs With Low Sliding Ratio Under Mixed Elastohydrodynamic Lubrication

Abstract

The relative sliding at the meshing point directly affects the contact and lubrication characteristics of the gear pair, and is the main cause of gear wear and power loss. In this research, for investigation of a new type of low sliding ratio (LSR) gear pair whose tooth profile is constructed by a cubic function, a Three-dimensional (3D) mixed EHL line contact model was established with consideration of the effect of tooth profile geometry, transient motion characteristics, load distribution and machining roughness. The distribution of the center film thickness of the LSR gear along the meshing line was predicted through an example the result of which was compared with a typical line contact EHL formula to verify the model. In addition, the difference was investigated in film thickness distribution, of friction coefficient and temperature rise between LSR spur gears and involute spur gears. Basing on above, there was discussion about the effect of 3D rough tooth surface on the contact lubrication characteristics of LSR gears. The results demonstrated that the minimum center film thickness of the LSR gear appeared at the alternating point of the concave and convex tooth surfaces. At the same time, compared with the involute gear, the LSR gear significantly increased the film thickness at the start and ending points of the meshing, and reduced the friction coefficient and the flash temperature rise.

Non-Newtonian Thermo-Elastohydrodynamics and Sub-Surface Stress Field of High-Performance Racing Spur Gears

“…Therefore, it is expected that the effect of asperity contact on the predicted results would be insignificant. At relatively lower sliding speeds, however, the effect of asperity contact can become significant and should be considered [54].…”

“…It is important to determine the lubricant temperature in the EHL contact as well as the flash temperature rise of the contacting surfaces. A more detailed method would be to solve the energy equation which provides information about the temperature distribution within the contact [42,53,54]. However, this approach would significantly increase the computation times.…”

Fractal simulation of surface topography and prediction of its lubrication characteristics

“…Gear transmission is one of the most widely used mechanical transmission methods, and its reliability and service life are closely related to the lubrication performance of the tooth surface [1][2][3]. The machined tooth surface looks flat on a macro level, but its microscopic surface texture is uneven with a complex surface morphology, which causes the complexity of the tooth surface lubrication mechanism [4][5][6][7].…”