活塞偏心倾斜对双筒液压减振器动态阻尼特性影响分析*

考虑活塞偏心和倾斜后活塞与缸筒之间的摩擦与润滑因素,研究充气式双筒液压减振器动态阻尼特性;建立活塞偏心和倾斜的双筒式液压减振器的动态阻尼特性数学模型和动压润滑方程,求解减振器动态阻尼特性数学方程;采用雷诺空化边界条件,对Reynolds方程采用五点差分法进行离散,利用超松弛迭代法(SOR)迭代求解,得到摩擦阻尼力;分析活塞偏心距比、活塞倾斜角度,活塞倾斜时活塞运动速度、活塞半径、活塞宽度等因素对摩擦阻尼的影响,以及各摩擦因素对减振器动态阻尼特性的影响。结果表明:活塞偏心和倾斜时,随活塞速度、偏心距比、活塞倾斜角度、活塞宽度等的增加,减振器活塞与缸筒之间的油膜摩擦力均增加,而随活塞半径的增加,油膜摩擦力减小。减振器活塞发生倾斜时,会造成阻尼力的大幅增加,严重影响车辆行驶的舒适性能,且活塞速度越快,对舒适性影响越严重。

Analysis on Dynamic Damping Characteristics of Hydraulic Vibration Absorber with Eccentric and Inclined Piston

Considering the friction and lubrication between eccentric and inclined piston and cylinder,the dynamic damping characteristics of inflatable double cylinder hydraulic shock absorber were studied.The dynamic damping characteristics mathematical model and hydrodynamic lubrication equation of double cylinder hydraulic shock absorber with eccentric and inclined piston were established,and the dynamic damping characteristic mathematical equation of the shock absorber was solved.Using Reynolds cavitation boundary conditions and five point difference formula to discretize Reynolds equation,the friction damping force was obtained by successive over relaxation iteration method (SOR).The influence of eccentricity ratio,inclination angle,moving velocity of inclined piston,radius and width of piston on friction damping,and the influence of various friction factors on dynamic damping characteristics of shock absorber were analyzed.The results show that when the piston is eccentric or inclined,the oil film friction between the piston and the cylinder is increased with the increase of piston speed,eccentricity ratio,piston inclination angle and piston width,and is decreased with the increase of piston radius.The damping force will increase greatly when the piston is eccentric or inclined,which will seriously affect the comfort of driving.And the faster the piston speed,the more serious the impact on the comfort.