Abstract:In order to reveal the characteristics of elastohydrodynamic lubrication(EHL)under the velocity impact conditions,optical interferometry experiments were performed on the optical interference test rig by using steel ballglass disk point contact and different oils including PAO40,PAO100 and PB680.The surface tension of three kinds of oils was compared by the contact angle measurement.The variations of oil film thickness of three kinds of oils at different instant in the accelerating phase,constant speed phase and deceleration phase were studied,and the influence of the running time of constant speed phase on the oil film was also studied.Results show that the contact angles and surface tension of the oils on different material surface are increased with increasing of oil viscosity,the oil with larger viscosity has smaller Hertzian contact area under the same working conditions.In the acceleration phase,the film thickness of different oils is increased from the inlet,whereas the response of the film thickness is relatively slow in the contact region and at the exit.In the later acceleration stage and the constant speed maintenance phase,the oil with high viscosity has a larger film thickness.In the deceleration phase,the film thickness of the three kinds of oils in the inlet is decreased firstly,and the response rate of PB680 with high viscosity is slower.The film thickness of the three kinds of oils is increased firstly and then reduced in the constant speed maintenance phase.When changing the maintenance time at the constant speed stage under the same conditions,the film thickness of the oil is in an increasing state when the constant time is relatively short,while the film thickness is increased firstly and then decreased when the constant time is relatively long.
