The paper presents a combined solution for multi-body dynamics of a modified cycloidal cam to flat follower with transient lubricated finite line contact conjunction. The solution to the dynamics of the valve train system is undertaken in the Euler frame of reference, which includes valve surge due to the non-linear behaviour of the spring. The elastohydrodynamic transient contact conjunction is analysed in each integration step time by simultaneous solution of the Reynolds' equation in space-time co-ordinates with the instantaneous elastic film shape equation, taking into account the generalized contact elasticity for finite line contact geometry. This approach, not hitherto reported in the literature, yields high generated pressures and thin films at contact extremities that govern wear and fatigue spalling performance of such contacts. Results show that the usual approaches in both quasi-static analyses and transient line contact solutions yield results that are not in line with actual prevailing conditions.

Transient elastohydrodynamic lubrication of finite line conjunction of cam to follower concentrated contact

A finite element approach of thin film lubrication in circular EHD contacts

In this paper a full numerical solution for the partial elastohydrodynamic lubrication in heavily loaded line contacts is obtained by using a Newton-Raphson iterative technique presented by Houpert and Hamrock (9). The results obtained from present work confirm the major conclusions by Path and Cheng (3), and by Zhu and Cheng (6), and demonstrate the effects of surface roughness on the pressure spike and the lubricant film constriction. Presented at the 44th Annual Meeting in Atlanta, Georgia May 1–4, 1989

Effect of Surface Roughness on Pressure Spike and Film Constriction in Elastohydrodynamically Lubricated Line Contacts

This paper presents numerical solution of isothermal elastohydrodynamic conjunction for concentrated contact of elastic bodies under the elliptical point contact condition The solution includes the effect of squeeze-film motion that occurs under transient conditions due to the application of cyclic loads and/or oscillating motions in machine elements It is shown that this time-dependent behaviour increases the load-carrying capacity of the contact which is largely responsible as a mechanism of lubricant film formation when the low speeds of entraining motion yield a low film thickness An extrapolated oil-film thickness formula is also presented that can be employed under dynamic conditions

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Elastohydrodynamic solution for concentrated elliptical point contact of machine elements under combined entraining and squeeze-film motion:

A numerical solution to the problem of thermal compressible elastohydrodynamic lubrication of rolling/sliding contacts has been tested over a wide range of operating parameters consisting of dimensionless load, speed, slip, and material parameters A least squares exponential curve fit was used to develop simple formulas for the amplitude and location of the pressure spike, the minimum film thickness, and the maximum lubricant temperature as a function of the operating parameters These equations can be used to evaluate parameters affecting the performance of rolling/sliding heavily loaded lubricated contacts Presented at the 45th Annual Meeting in Denver, Colorado May 7–10, 1990

Formulas Used in Thermal Elastohydrodynamic Lubrication

Influence d'une pointe de pression dans un contact elastohydrodynamique sur la fatigue d'un palier de roulement

J. C. Kuypers

Papers

The Effect of the EHD Pressure Spike on Rolling Bearing Fatigue