Study On Friction, Wear And Lubrication Characteristics Of Rotary Seals Materials In Automotive Transmissions

Rotary seal rings is a special type of face seals, which play an important role in rotating oil supply device of automotive transmission, such as wet clutches, brakes and torque convertor. Characteristics of seal ring directly affect the overall performance of the driveline, once the seal failure occurs, thus will result in total failure of transmission.Typical materials of rotary seal are cast iron, PTFE and PEEK. In order to guarantee the working performance of the rotary seal, reduce the friction power loss and wear, improve the lubrication condition, usually in the rotary seal working face have some shallow or deep grooves. Cast iron has the larger elastic modulus compare to PTFE and PEEK materials. And processing method of shallow groove is not suitable for plastic materials. So the shallow grooves are often used in the cast iron material of the rotary seal, and the PTFE and PEEK material of the rotary seal with deep grooves.This paper is to study the rotary seal in Automotive Transmissions. And a preliminary research on the fluid dynamic calculation of the rotary seal with a shallow groove and the circumferential deformation of the deep groove is carried out. In the calculation of the circumferential deformation of the deep groove seal ring, the stress of the sealing ring is divided into axial, radial and tangential directions respectively. And the calculation expression of circumferential deformation is obtained by Fourier triangle transform and triangle function stack.The force balance equation in axial direction of the rotary seal is constructed. The calculation models of hydrodynamic lubrication and the bearing capacity of the rough peak is established. The oil film thickness, oil film bearing capacity and rough peak load are obtained by simulation calculation in different working conditions. Carry out the oil film thickness measurement and verification tests. The experimental results show that the shallow groove rotary seal can produce a fluid pressure and a certain thickness of the oil film in the working surface.The experimental study on the friction and wear characteristics of the typical rotary seal materials under the condition of boundary lubrication was carried out through the diskpin test. The experimental results show that the wear rate of the three materials increases with the increase of the load. But its changing trend with the speed is complex. Observe the worn surfaces of the three materials. Learn that the wear form is mainly abrasive wear and adhesive wear.Rotary seal wear test of typical materials and film thickness test get a lot of experimental data. The fitting surface formula of wear rate of three typical rotary seal materials was obtained.