往复运动条件下润滑油膜特性的实验观察

采用多光束干涉技术观察往复运动条件下润滑油膜的滑移及黏弹特性,研究振幅和频率对往复动态润滑弹流油膜的影响。结果表明:往复运动过程中,在特定时刻气穴的出现使油膜厚度逐渐减小,削弱了滑移程度;因润滑油的黏弹性而引起的运动滞后导致了油膜的非对称性;频率增大时,正行程末端时膜厚明显增大,油膜输送速度也随着增大;而负行程末端油膜受气穴的影响膜厚增大较慢;振幅(输入位移)增大时,正行程末端时油膜整体平移,而负行程末端入口凹陷呈现先变明显而后消失的现象。

Observations of Lubricant Film Properties under Reciprocation Conditions

Using muti-beam optical interferometry,the properties of boundary slippage and the viscoelasticity of the lubricant film were observed under reciprocating motion conditions.The influence of the amplitude and frequency on dynamic EHL films was investigated.The results show that during the reciprocation,the film thickness decreases and the slippage magnitude decays due to the attendance of the cavitations at the specific instants.The film profile can not maintain its origin symmetry because of the tardy movement of the lubricant influenced by the viscoelasticity.As frequency increases,the film thickness and the lubricant velocity increase obviously at the end of positive stroke.By contrast,due to the appearance of the cavitation,the increase tendency of film thickness slows down at the end of negative stroke.With amplitude(input displacement)increasing,at the end of positive stroke,the whole lubrication film moves.However,at the end of negative stroke,the inlet dimple becomes more obvious first and then disappears.