EHD Film Forming Capability and Boundary Lubrication Characteristics of Hindered Polyol Esters

摘要

Among ester-type synthetic lubricating oils, those substances whose principal skeleton is neopentyl-type alcohol that has no hydrogen bonds in β positions of the alcohol skeleton are called hindered polyol esters (POE). POE shows a thermal oxidation stability that is much higher than that of mineral oils. Since POE offers a good compatibility with HFC refrigerant and very high electrical insulation properties, it is used as an alternative refrigerant compatible refrigerator oil for electric refrigerators. Also, it is suggested that with ever-growing concern about environmental problems, the need for POE will increase in the future because of the expected compatibility of POE with environmental requirements. In the case of using POE as a lubricating oil, the application of additives is indispensable, and studies of the effects of different additives added to POE on tribological properties are carried out [1,2]. However, the tribological properties of POE itself have not been sufficiently clarified. In the present study, the friction characteristics of POE-based oil are investigated by measuring the thickness of oil films in the region of elastohydrodynamic lubrication and by measuring the coefficient of friction under boundary lubrication conditions.