Effects of temperature on pure squeeze EHL motion using grayscale interferometric method

摘要

Purpose - The purpose of this paper is to present a novel method to investigate the microscopic mechanism of the oil film under the pure squeeze elastohydrodynamic lubrication (EHL) motion. An optical EHL squeeze tester is used to explore the effects of squeeze velocity, load, temperature, and lubricant viscosity on the dimple film thickness that occurs when a ball approaches a flat plate covered by a thin layer of oil. Design/methodology/approach - The grayscale interferometric technique was used to study the thickness of the lubricating film in an EHL point contact. The light source was a He-Ne laser. Through the transparent optical glass and by means of optical interference, the interference fringe patterns of the contact region were observed by a charge-coupled device camera recording. The two elastic bodies were a sapphire disk and a steel ball. The contact was lubricated with paraffin-based oil. Findings - Results show that increasing the squeeze speed, load, viscosity, and decreasing the temperature, make the dimple deeper, and the contact area increases. Moreover, as the squeeze speed and load decrease and temperature increases, the fluidity of the lubricant increases and less time is needed to extrude. The maximum thickness of the dimple increases with increasing squeeze speed, load, lubricant viscosity, and decreasing temperature. The greatest effect of pure squeeze EHL motion is found with squeeze velocity, followed by load, and then temperature for the same lubricant viscosity. Originality/value - The paper usefully describes the use of a self-development optical EHL squeeze tester to explore the effects of temperature, squeeze velocity, load, and lubricant viscosity on the dimple film thickness which occurs between two components approaching each other.