The influence of rounded pores' diameter and depth at sliding faces on the coefficient of friction under oil lubrication

摘要

The effects of the depth and the diameter of pores on the coefficient of friction f was investigated by ring-on-ring rotation4ype sliding tests under oil lubrication conditions by using test specimens, the sliding surfaces of which were provided with rounded pores. In the tests, the diameter of pores was 50-200 μm, the depth of the pores was 3-18 μm, and the effects of the load, the speed of sliding, and the coefficient of viscosity of test fluid were taken into consideration. As a result, the effect of pores on a spreading of the fluid lubricated area and the prevention of seizure development was determined. The relationship between the depth of pores and the coefficient of friction f showed the existence of a region where the coefficient of friction f decreases with an increase of the depth of pores and a region where it increases with the depth of pores. According to the relationship between the diameter of pores and the coefficient of friction f, in the case where the depth of pores was constant, the coefficient of friction f decreased with an increase in the diameter of pores and in the case when the ratio of the pore depth to the pore diameter was constant, the coefficient of friction f increased with an increase in the diameter of pores. In the case when the shape of pores was constant, the same coefficient of friction f was obtained if the dimensionless characteristic number G was the same under fluid lubrication conditions, even if the speed of sliding and the viscosity coefficient of the test fluid changed.