Oil film variation and surface damage in the process of reciprocation-oscillation transformation

In this study, optical interferometry experiments were carried out on a ball-disk test rig to study the change of elastohydrodynamic lubrication (EHL) in reciprocation to boundary lubrication (BL) in oscillation for the contacts of pure rolling and simple sliding motions. Then, using an SRV wear tester, the corresponding tribological performance during the transformation from the reciprocating motion to the oscillating motion under simple sliding condition was evaluated. The experimental results show that the BL area in the contact zone gradually increases with the decrease of the stroke length, so that the area of entrapped oil film by the squeeze effect is gradually decreased. The experiments by the SRV tester revealed that, with the decrease of stroke length, the surface damage become more severe. The article aims to synthesize the variation of the EHL film and the BL film as well as the sliding wear and fretting during the transformation of the reciprocating to oscillating motion.