The Study on Grease Mixed-Lubrication Model of Point Contact Pair

doi:10.3901/JME.2022.01.145

Abstract

Abstract: Considering the non-Newtonian characteristics of the grease and the asperity geometry of the rough surface, and based on the Herschel-Bulkey rheological model and the K-E elastoplastic contact model, the parallel processing of the hydrodynamic action of the lubricant and the asperity contact was determined. Combined with the proposed assumption of the boundary condition between the elastodynamic contact zone and the asperity contact zone, a deterministic model of grease mixed-lubrication of the point contact is established. The iterative method of the mixed-lubrication model is constructed by combining the virtual pressure substitution method used to deal with the boundary condition, and then lubrication characteristics under different greases and rough surfaces are studied. The results show that the secondary pressure peak and the necking feature are no longer obvious due to the surface roughness, and multiple pressure peaks appear in the lubrication area, and the pressure peak increases with decreasing speed and increasing roughness. There is no monotonic relationship between the film thickness and the grease consistency grade. When the film thickness ratio is less than about 4, the contact enters the mixed-lubrication state. The skewness of the rough surface has a certain effect on the mixed-lubrication.

Key words: grease, point contact, mixed-lubrication, rough surface, roughness

CLC Number:

TG156

WU Zhenghai, XU Yingqiang, LIU Kaian, CHEN Zhiyong. The Study on Grease Mixed-Lubrication Model of Point Contact Pair[J]. Journal of Mechanical Engineering, 2022, 58(1): 145-153.

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