Study On The Time-varying Failure Mechanism Of The Brake Piston Seal For The Clamp Dise Brake

The sealing structure of the brake piston can related to the sensitivity and reliability of the brake directly.It’s important to study the failure mechanism of the brake piston seal for improving the brake performance of the brake.This paper proposed the special-shaped seal ring to replace the standard seal ring to aim at the drawback of the O-ring.Therefore,the mechanical and sealing performances in different influence factors of quincunx-ring were analyzed based on ANSYS Workbench and Fluent..First,analyzed the sealing mechanism of O-ring and quincunx-ring of the brake piston.The time-dependent reliability model of quincunx-ring under two failure modes of shear stress failure and leakage failure was established.Then the reliability of quincunx-ring under single failure mode and multi effect failure mode is obtained.Based on the Mooney-Rivlin constitutive model of rubber materials,a nonlinear finite element analysis of the quincunx-ring was built up.The influence of different friction factors,brake fluid pressure and compression were analyzed on the pressure cloud diagram and compared with the O-ring.The results show that stress of quincunx-ring changes very little so it can avoid the stress concentration and the sealing performance is better than the O-ring.The working life of the ring can be increased.At last,we calculated the maximum pressure gradient sealing contact surface oil film through the finite element method to calculate and extract the maximum pressure according to the Reynolds equation of elastic fluid hydrodynamic seal interface in quasi one dimensional flow dynamic oil film pressure braking model.Then calculated the film thickness range and leakage in a reciprocating movement of the piston.The effects of different factors on the thickness and leakage of oil film were analyzed and the results were compared with the O – ring’s.It can be concluded that the wear of the quincunx-ring is smaller than the O-ring and quincunx-ring has the ability of good anti leakage and sealing performance.This paper can obtain the high efficiency and reliable seal structure of the brake piston,which have important value and significance for the design and parameter matching of sealing ring.At the same time,the results can also be extended to other similar service environment static sealing occasions,with good technical and economic benefits and far-reaching social significance.