液压往复密封件磨损失效概率研究

根据摩擦副系统可靠性理论,对液压往复密封件的磨损失效概率进行研究,提出了一种检测密封件磨损失效的方法。以液压缸杆密封Y形密封件为研究对象,通过ANSYS仿真分析密封件在不同磨损程度下摩擦应力和失效概率变化规律,计算密封件在运行过程中磨损失效概率,并通过试验验证有限元计算结果的有效性。结果表明:Y形液压往复密封件唇口处摩擦应力较大,因此其磨损部位主要发生在唇口;随着磨损程度的增加,Y形密封件受到的摩擦应力增加,失效概率也随之变大。研究表明,提出的方法可对液压缸实际运行过程中往复密封件的磨损进行检测。     

基于有限元分析的液压往复密封优化设计

利用大型通用有限元分析软件ANSYS对液压缸往复密封用O形橡胶密封圈进行建模和计算,分析O形密封圈最易受损和失效的关键部位,并结合液压缸活塞杆动态密封机理提出了优化设计模型.为往复密封的优化设计指出了一种可行的设计方法.     

谈液压橡胶密封件的使用和维修

本文介绍了液压橡胶密封件的使用性能,结构形式及密封机理;密封材质与液压油液的相容性及其对密封件的影响;几种常见橡胶密封件的使用性能,装配要点及其失效的形式和原因;同时提出液压橡胶密封件维修注意事项及预防失效的措施。     

常用往复密封件的选型与应用

该文解析了各种往复密封件密封机理，提出合理的选型方案及使用注意点。     

航空往复型密封件性能评价技术研究

往复型密封件是影响飞机安全和可靠性的重要部件,与国外完善的评价标准体系相比,国内往复型密封件性能考核标准极度匮乏,尤其是关键的动密封性能和抗挤出性能评价标准。该文详细分析了往复型密封件所处的复杂工况,提出了静密封性能、动密封性能以及抗挤出性能评价技术及方法,并给出了相关夹具的结构和原理。     

转叶式舵机密封件在不同磨粒尺寸下的摩擦学特征研究

船舶转叶式舵机因体积小、功率密度高而逐渐替代传统的柱塞式舵机.然而,磨损过程中产生的磨粒常使叶片密封件产生异常磨损,引起密封失效,导致油压下降,造成转叶式舵机功能丧失.明晰叶片密封件与缸体内壁之间的摩擦磨损机理以及提取关键磨损特征是提高叶片密封件的磨损寿命和实现转叶式舵机智能故障诊断的关键.以常用于制作密封件的聚氨酯高...     

往复压缩机密封件及摩擦磨损研究进展

在往复压缩机的使用过程中,气阀、活塞环、填料环等密封件起到关键的密封作用,保障了压缩气体的稳定。密封件的耐磨程度,决定着泄漏量的大小,也直接关系着产品的性能。近年来,人们对密封件的常用材料——聚四氟乙烯(PTFE)、聚醚醚酮(PEEK)及其复合材料,进行了深入的摩擦学研究,取得了大量的研究成果。在介绍往复压缩机原理和密封件的基础上,对往复压缩机所用PTFE、PEEK及其复合材料的摩擦学研究进行综述,为今后往复压缩机密封件摩擦学研究提供帮助。     

液压往复密封理论、技术与应用的进展研究

综述了液压往复密封偶合面的摩擦、磨损和润滑，从边界润滑液膜的形成，密封失效的机制和动力润滑密封方面，评述了液压往复密封理论的研究进展。通过液压往复密封的结构设计方法、材料、应用及其技术进展分析，提出密封件截面形状的变化、新型的组合密封仍是未来往复密封的主要结构形式，密封性能和耐磨特性的改善和提高，密封结构和材料的进一步分离，往复密封的可控性提高、系统内部资源的充分利用是未来往复密封的研究热点和发展趋势。     

矩形密封圈的增效运行参数研究

建立矩形密封圈的混合润滑模型,分析工作压力、活塞杆运行速度和密封件粗糙度对轴向往复用矩形密封圈的摩擦力矩、泄漏量的影响。结果表明:过大的密封压力会对密封件造成损坏,使得摩擦力和净泄漏量极速增大;往复速度的增加会使摩擦力线性增大,直线往复密封的净泄漏量随着表面粗糙度的增大表现为越来越大的增量。利用田口实验设计方法对矩形密封圈操作压力、运行速度和密封件粗糙度进行正交试验,分析得到最优参数组合,并得到各影响因素对密封性能的影响程度由大到小依次为往复速度、粗糙度、密封压力。     

高压柱塞泵往复密封性能及机理的研究

本文叙述了对柱塞泵往复密封件沿轴向压力分布、泄漏量随压力变化进行的测试;利用Naiver-Stokes方程和有限元理论,对密封件的压力沿轴向的分布规律、泄漏量与压力变化关系进行了计算。通过试验,验证了理论计算结果的重要性,从而揭示了它的密封机理。     

Fluid-solid interaction model for hydraulic reciprocating O-ring seals

Elastohydrodynamic lubrication characteristics of hydraulic reciprocating seals have significant effects on sealing and tribology performances of hydraulic actuators,especially in high parameter hydraulic systems.Only elastic deformations of hydraulic reciprocating seals were discussed,and hydrodynamic effects were neglected in many studies.The physical process of the fluid-solid interaction effect did not be clearly presented in the existing fluid-solid interaction models for hydraulic reciprocating O-ring seals,and few of these models had been simultaneously validated through experiments.By exploring the physical process of the fluid-solid interaction effect of the hydraulic reciprocating O-ring seal,a numerical fluid-solid interaction model consisting of fluid lubrication,contact mechanics,asperity contact and elastic deformation analyses is constructed with an iterative procedure.With the SRV friction and wear tester,the experiments are performed to investigate the elastohydrodynamic lubrication characteristics of the O-ring seal.The regularity of the friction coefficient varying with the speed of reciprocating motion is obtained in the mixed lubrication condition.The experimental result is used to validate the fluid-solid interaction model.Based on the model,The elastohydrodynamic lubrication characteristics of the hydraulic reciprocating O-ring seal are presented respectively in the dry friction,mixed lubrication and full film lubrication conditions,including of the contact pressure,film thickness,friction coefficient,liquid film pressure and viscous shear stress in the sealing zone.The proposed numerical fluid-solid interaction model can be effectively used to analyze the operation characteristics of the hydraulic reciprocating O-ring seal,and can also be widely used to study other hydraulic reciprocating seals.     

基于斯特封的往复密封摩擦磨损界面性能实验研究

斯特封是常用的往复密封件,其中斯特封的PTFE圈性能及活塞杆表面材料在往复密封过程中起着重要作用。搭建往复密封实验台,取4组添加碳纤维PTFE的密封圈分别与镀Cr膜活塞杆和镀DLC膜活塞杆进行往复密封台架实验,实验后获取使用过的4组密封圈作为实验样本,并取1个全新未使用的添加碳纤维PTFE的密封圈作为参考样本。通过三维白光干涉表面形貌仪、场发射环境扫描电子显微镜和冷场发射高分辨扫描电子显微镜分别对实验样本的密封唇进行表面形貌、表面磨损和磨损表面元素进行测定。通过实验测定,得出镀膜材料脱落形成磨粒导致密封圈表面磨损。还对密封圈的加工方法和活塞杆镀膜材料的选择提出了建议。     

混合润滑状态下旋转唇形密封的失效机制模型

为探究旋转唇形密封的失效机制,综合考虑流体、微凸体、弹性变形和温度对旋转唇形密封的影响,构建旋转唇形密封多场耦合模型,并基于多场耦合模型与关键点更新策略提出混合润滑状态下旋转唇形密封的磨损退化模型仿真方法。通过设计故障模拟试验,将试验结果与仿真结果进行对比,验证了仿真方法的有效性。结果表明：唇形密封件在初期磨损速率较大,之后趋于平缓;唇尖处接触压力最大,磨损速率最大。     

Reciprocating seals

Some of the fundamental work on reciprocating seals is reviewed and ways in which the results can be used in the practical choice of seal types and of seal materials for specific applications are considered. Variation of seal performance from one application to another is discussed     

往复压缩机填料密封失效分析及措施

对往复压缩机的填料密封故障进行了失效分析,介绍了填料密封的密封原理;通过故障分析找到了解决措施.目前,改进后的压缩机已应用于工业生产,运行一年多密封填料一直正常,达到了预期效果,确保了装置平稳生产.     

Wear Testing of Seals in Magneto-Rheological Fluids©

Magneto-rheological (MR) fluid-based dampers can be used in suspensions to modify ride, handling, and suspension frequencies in autos. We have developed a unique seal wear test method to simulate the wear of rod seals in Magneto-rheological fluid-based dampers. In this test, seal material samples in the form of rectangular coupons are immersed in a bath of MR fluid, and a section of the rod is brought into contact with the seal coupon. The rod is loaded against the coupon with a known normal force, and a variable-frequency reciprocating machine is used to stroke the rod back and forth across the material coupon surface. Test conditions such as normal load, frequency and amplitude of oscillation, and temperature are adjusted to simulate desired conditions. This bench test method ranks various seal materials qualitatively in the correct order (as determined in field tests with these seal materials) in terms of wear and abrasion resistance and constitutes a valid test procedure for the screening of seal materials, MR fluids, and rod surface coatings.     

Transient EHL analysis of an elastomeric hydraulic seal

Recent steady-state numerical analyses of reciprocating hydraulic rod seals have revealed many important details about the operation of such seals, including the fact that they generally operate with mixed lubrication in the sealing interface. However, these seals frequently operate under transient conditions, with the rod speed and sealed pressure undergoing cyclic variations with time. In the present study, a transient numerical model has been developed to take account of the varying rod speed. The model consists of a fluid mechanics analysis of the lubricating film of hydraulic fluid, a contact mechanics analysis of the contacting asperities on the seal lip and a structural analysis of the seal deformations. The fluid mechanics analysis consists of a finite volume solution of the Reynolds equation using a mass-conserving algorithm, which accounts for possible cavitation. The contact mechanics analysis utilizes the Greenwood–Williamson model. The structural analysis consists of a finite element analysis. Typical results are presented for an injection molding application. Of greatest importance is the net leakage per cycle. Also presented are the cyclic histories of such performance characteristics as the lubricating film thickness, contact pressure and fluid pressure distributions, the friction force on the rod and the instantaneous flow rate.     

Coaxial twin-shaft magnetic fluid seals applied in vacuum wafer-handling robot

Compared with traditional mechanical seals,magnetic fluid seals have unique characters of high airtightness,minimal friction torque requirements,pollution-free and long life-span,widely used in vacuum robots.With the rapid development of Integrate Circuit(IC),there is a stringent requirement for sealing wafer-handling robots when working in a vacuum environment.The parameters of magnetic fluid seals structure is very important in the vacuum robot design.This paper gives a magnetic fluid seal device for the robot.Firstly,the seal differential pressure formulas of magnetic fluid seal are deduced according to the theory of ferrohydrodynamics,which indicate that the magnetic field gradient in the sealing gap determines the seal capacity of magnetic fluid seal.Secondly,the magnetic analysis model of twin-shaft magnetic fluid seals structure is established.By analyzing the magnetic field distribution of dual magnetic fluid seal,the optimal value ranges of important parameters,including parameters of the permanent magnetic ring,the magnetic pole tooth,the outer shaft,the outer shaft sleeve and the axial relative position of two permanent magnetic rings,which affect the seal differential pressure,are obtained.A wafer-handling robot equipped with coaxial twin-shaft magnetic fluid rotary seals and bellows seal is devised and an optimized twin-shaft magnetic fluid seals experimental platform is built.Test result shows that when the speed of the two rotational shafts ranges from 0-500 r/min,the maximum burst pressure is about 0.24 MPa.Magnetic fluid rotary seals can provide satisfactory performance in the application of wafer-handling robot.The proposed coaxial twin-shaft magnetic fluid rotary seal provides the instruction to design high-speed vacuum robot.     

可磨式密封在离心压缩机上的应用

介绍了离心压缩机可磨密封的原理、结构、应用背景及密封对离心压缩机性能的重要作用,列举了国内外离心压缩机的常用可磨耗封严涂层材料、机械用碳材料的材料种类和性能指标,以及离心压缩机密封的主要泄漏形式,并进行了普遍密封与可磨密封的对比试验,验证了可磨密封对单级压缩机模型性能的影响。