The effects of a transversely oriented bump on point contact EHL films in reciprocating motion with a short length of stroke

Under conditions of a short stroke and a high frequency of reciprocation, a local collapse of EHL films is easily induced, because air bubbles produced in the previous stroke result in oil starvation in the following stroke. Furthermore, thin films produced by a transversely oriented bump entering: the EHL conjunction travel through the contact area with approximately the average speed of the contacting surfaces while holding its shape and thickness. In this paper, the effects of above two important phenomena on point contact EHL films and traction forces in reciprocating motion having a relatively short length of stroke are discussed through direct observations using the duochromatic optical interferometry technique. The effects of surface kinematic conditions have also been discussed.