The Friction Reduction and Stick–Slip Inhibition Effects of Ultrasonic Vibration on Sliding Friction Pair Under Solid Lubrication

Abstract

Frictional vibration often occurs in sliding process, or called stick–slip phenomenon, which is easier to exist in the range of Stribeck curve where friction and velocity have negative gradient characteristics. The kinetic friction force can be approximately linearly increased with velocity in the sliding stage of solid lubrication. Solid lubrication avoids the negative gradient friction range under dry friction and has a good inhibiting effect on stick–slip phenomenon. In this study, by applying ultrasonic vibration to metal/metal sliding friction pairs, the friction reduction and stick–slip inhibition effects of ultrasonic vibration on sliding friction pairs moving at low velocities (0.05–1.0 mm/s) under solid lubrication was studied. In solid lubrication, the reduction of ultrasonic vibration on static friction force reached 60%, and the maximum reduction in kinetic friction force was 83%, which decreases with the increase of sliding velocity. A pre-displacement model of ultrasonic vibration friction reduction is proposed which is in good agreement with the experimental data. Under the condition of solid lubrication, when the driving velocity is 0.05 and 0.1 mm/s, the slider has a low displacement fluctuation, and the application of ultrasonic vibration has little change in the displacement fluctuation. When the velocity continues to increase, the displacement fluctuation increases rapidly, and ultrasonic vibration can effectively inhibit the displacement fluctuation with the rapid increase of velocity. The velocity range of high-precision motion under solid lubrication after applying ultrasonic vibration is increased.