Influence of circularity errors of the journal on the lubrication performance of sliding bearings

This work explores the changes of lubrication performance of sliding bearings caused by oval or tooth circularity errors of the journal. The analytic expression of oil film thickness of the sliding bearing with noncircular journal was derived. For a main bearing of an internal combustion engine, the relationships between various circularity errors of the journal and bearing lubrication parameters were studied, such as film thickness, film pressure, friction power loss, lubricant flow volume and orbital path at center. The results show that both of oval and tooth circularity errors would decrease the lubricious characters of sliding bearings evidently. When oval circularity errors occur, the area of load bearing region would be changed so that the lubricious performance at the circumferential extent could be improved at a time. The tooth errors would bring a periodic fluctuation of lubricant film at the load bearing region and the profile of film pressure has a multi-peak distribution.