Abstract

Reciprocating seals are essential elements for hydraulic cylinders. The status of the contact area between the seal and the counterpart directly determines the sealing performance. An optical test rig for the O-ring seal was constructed in this study to investigate the tribological characteristics among the contacting zone, where the cylinder was changed to be transparent and a microscope is employed to observe and record the sealing status. A numerical method coupling finite element analysis (FEA) and the mixed lubrication procedure is implemented for the theoretical analysis. A comparison between the simulation and the experiment for the sealing width, friction force, and leakage was conducted. During the reciprocating motion, it was found that the oil film thickness adhering onto the cylinder’s inner wall was not even along the axial direction and that the leakage oil would be accumulated at the stroke-end position because of the seal’s scraping effect. The topographic indicators for the contact mechanisms are discussed, and the results demonstrated that the implementation of the mean peak width (Rsm) for the asperity radius could obtain more reasonable results. The performance of the O-ring seal at different velocities was theoretically and experimentally investigated. With an increase in velocity, the leakage rate increased and the friction force decreased. The simulation results are consistent with the experimental results both in the overall trend and in the order of magnitude.

摘要

往复式密封件是液压缸必不可少的元件。密封件与配对件接触面积的状况直接决定了密封性能。本研究搭建了O型密封圈光学试验台，研究了接触区之间的摩擦学特性，将圆柱体改为透明，并用显微镜观察并记录密封状态。采用数值方法耦合有限元分析 (FEA) 和混合润滑程序进行理论分析。对密封宽度、摩擦力和泄漏的模拟和实验进行了比较。在往复运动过程中，发现沿轴向粘附在气缸内壁上的油膜厚度不均匀，由于密封件的刮擦作用，泄漏油会聚集在行程末端位置。讨论了接触机制的地形指标，结果表明平均峰宽的实施（Rsm ) 为凹凸半径可以获得更合理的结果。理论和实验研究了 O 形密封圈在不同速度下的性能。随着速度的增加，泄漏率增加，摩擦力减小。模拟结果在总体趋势和数量级上都与实验结果一致。