Improving the tribological parameters of the piston of a telescopic automobile shock absorber

At present, when designing a vehicle, increased requirements are imposed on its suspension, primarily related to the task of ensuring a high level of smoothness, isolation of the body from vibration and road noise. The shock absorber is equally designed to ensure both comfort and driving safety. To operate the vehicle suspension even on small road bumps, the shock absorber should have as little internal friction as possible. The piston-cylinder interface of the shock absorber is one of the main sources of tribological losses. One of the most promising means of reducing losses is profiling the guide part of the piston. The paper proposes a method to determine the hydromechanical characteristics of a tribo-conjugate in a shock absorber, such as friction power loss, lubricant consumption through the gap, the minimal thickness of the lubricant layer for a cycle. For this purpose, an approximation of the profile shape of the piston guide part by continuous dependencies is proposed. To solve the Reynolds equation, numerical-analytical methods based on the finite-difference approximation of the differential operators of the boundary-value problem with free boundaries are used. To assess the influence of design parameters on hydromechanical characteristics, parametric studies were carried out. The finite-element method was used to solve the quasistatic problem of thermoelasticity, and temperature deformations of the piston were determined. A method for improving the hydromechanical characteristics by varying the geometric parameters of the conjugation is proposed. The results of calculations of various designs are presented. The proposed methods are universal, the use of the developed approaches at the design stage allows us to create more reliable, durable and efficient telescopic car shock absorbers.