液压缸缓冲动态特性对比研究

Comparative Study on Dynamics Performance for Cushion Process of Hydraulic Cylinder

在低速重载情况下,液压缸通常设置缓冲装置来避免活塞在行程末端撞击缸壁。针对缓冲过程中各物理量对缓冲动态特性的影响,将该缓冲过程分为局部压力损失、锐缘节流和可变节流三个阶段。为了准确描述各阶段之间的切换过程,建立数学模型及其切换标准,同时在考虑流场与活塞之间流固耦合效应的条件下,运用Fluent软件动态分析了液压缸缓冲过程,将数值解与仿真解作对比分析。研究结果表明:解析结果与数值仿真结果具有较好的一致性,末端间隙和外载荷对缓冲过程影响较为明显。

In the condition of low speed and heavy lo a d, a buffer device is usually set to prevent from the striking of piston and casting wall in the end of the trip. To study the influence of the physical quantities on the dynamic characteristics of the buffer, we divide the buffer process into three p h a se s： local pressure lo s s, sharp edges throttle and variable throttle. In order to accurately describe the switching process among th em , the mathematical models and switching standards for each phase are established. The software Fluent is used to analyze the dynamic cushion process under the consideration of the fluid-structure coupling effect between the piston and the flow field. Finally we compare the numerical solution and simulation solution to get the results. The analysis results show that the nu-merical results and simulation results have a good consistency, the end clearance and external load have obvious in-fluence on the cushion process.