Elastohydrodynamic Lubrication in Extended Parameter Ranges — Part III: Ellipticity Effect

Abstract

Elastohydrodynamic lubrication (EHL) is fundamental to mechanical components working under concentrated contacts, such as gears, rolling hearings, cams and followers, and traction drives/CVTs, etc. Today, the fast advancing technology and aggravated global competition require manufacturers to continuously upgrade and optimize their product design for high power density at low cost. This imposes a great challenge to engineering R & D due to the increasingly severe operating conditions. The EHL analysis, therefore, needs to be extended to cover wide parameter ranges and extreme conditions. This paper is the third part of a recent study and is focused on the effect of contact ellipticity on the EHL film thickness, following two previous papers that studied the effects of speed and load, respectively. In this paper, the ellipticity is varied in a wide range from 1/8 to 8. The study shows that, when the load is light and/or the speed is moderate, the current results agree well with the conventional EHL theory, especially for cases with the ellipticity ratio greater than 1.0. However, in the extended speed and load ranges, especially under severe conditions, the present analysis may give considerably thinner films than those from the conventional theory. The ellipticity effect on the film thickness appears to be dependent upon other parameters, such as load and speed. The heavier the load (or the lower the speed) is, the less significant the ellipticity influence will be.

Presented at the 58th Annual Meeting in New York City April 28–May 1, 2003

KEY WORDS:

• Elastohydrodynamic Lubrication (EHL)
• Film Thickness
• Elliptical Contact

Notes

Presented at the 58th Annual Meeting in New York City April 28–May 1, 2003