点接触弹流润滑供油条件退化的乏油分析

在点接触弹流润滑中,如果不能及时补充新油,则接触区的供油条件会随着润滑次数而退化。分析了供油油膜厚度、中心膜厚、最小膜厚和润滑油膜压力区形成位置与润滑次数的关系。结果表明:润滑开始时,由于供油油膜厚度较大,系统处于充分供油状态;随着润滑次数的增加,有一部分油从两侧泄漏,系统逐渐转到乏油状态,供油油膜厚度、中心膜厚和最小膜厚均逐渐变小,压力区形成位置则逐渐向Hertz接触区靠近;最终供油油膜厚度、中心膜厚和最小膜厚趋于定值,压力区趋于Hertz接触区,从而达到一种稳定乏油状态。

Analysis of Starvation in Elastohydrodynamic Lubrication Point Contacts with Degradation of the Oil-supply Condition

In an elastohydrodynamic lubrication(EHL) point contact,if the lubricant is not supplied in time,the condition of the oil-supply in the contact area will degrade with the increase in the lubrication time.The relations of the thickness of the supplied oil layer,central and minimum film thicknesses,the formating position of the lubricating film with the time of lubrication were investigated.The results show that,at the beginning of lubrication,because the thickness of the supplied oil layer is very large,the lubrication is in the fully-flooded state.With the increase in the lubrication time,some oil leaks from the sides of the contact,the lubrication changes into the starved state,and the thickness of the supplied oil layer,together with the central and minimum film thicknesses are gradually reduced,meanwhile the pressure build-up position is approaching the Hertzian contact.At last,the film thickness of the supplied oil layer,and the central and minimum film thicknesses approach fixed values,whereas the pressurized region inclines to the Hertzian contact,the lubrication,achieves a steady starved state.