钢球增力液压夹具

介绍了双钢球和三钢球增力机构与无杆液压缸组成的液压夹具系统,给出了其输出力和增力系数的计算公式。钢球增力机构与无杆液压缸组成的液压夹具,具有结构简单紧凑、制造工艺简便等优点     

绿色夹具:基于斜楔增力自锁机构的冲击式气动夹具

介绍了一种基于斜楔增力自锁机构的冲击式气动夹具的工作原理，给出了力学计算公式。该夹具由无杆活塞气缸与杠杆一斜楔式两级增力机构组成，突出特点是利用气缸活塞加速运动所产生的冲击力，来松开斜楔机构。该夹具在切削加工过程时间较长的场合，节能效果显著。     

基于无杆活塞缸的铰杆-杠杆增力双向夹紧液压夹具

介绍了两种由无杆活塞液压缸与双边铰杆-杠杆增力机构组成的双向夹紧液压夹具，分析了其工作原理，给出了理论与实际夹紧力的计算公式。相对于传统夹具，该类型夹具结构简单紧凑，刚性好，在输出力及液压缸直径一定的条件下，能显著降低系统的压力。     

基于铰杆-杠杆增力的两种液压夹具的技术性能对比

介绍了铰杆一杠杆增力机构与有杆活塞液压缸和无杆活塞液压缸组成的2种液压夹具,并通过对比提出了无杆液压传动相对于有杆液压传动具有结构紧凑、刚性好、摩擦损失小等优点.     

铰杆——斜楔式气动夹具增力机构设计及力学分析

设计了一种气动夹具增力机构,是利用典型的铰杆和斜楔增力模块组合成铰杆-斜楔式串联传动机构,通过角度效应,实现力的三级放大.介绍了该机构的组成及工作原理,按照力学模型推导出了增力系数和输出力的计算公式,分析了各工作参数对增力效果的影响.该机构具有结构简单、紧凑、增力系数大等优点,同时可利用单一输入力,实现气动夹具对工件进行双侧对称夹紧的过程.     

基于无杆活塞缸的斜楔增力液压夹具

液压传动夹具在现代制造业中应用极为广泛。液压缸的结构形式往往出于习惯而选择有杆活塞式液压缸。图1所示即为常用的基于有杆活塞液压缸的斜楔增力夹具，其工作时，斜楔的斜面在液压缸活塞杆的推动下作用于滚轮，使得杠杆式压板绕固定铰链轴转动，从而夹紧工件。     

增力自锁型手动夹具的设计及力学分析

设计了一种能够自锁的手动夹具增力机构,利用典型的杠杆、铰杆和斜楔增力模块组合成杠杆-铰杆-斜楔式串联传动机构,通过长度和角度效应,实现了力的三级放大。介绍了该机构的组成及工作原理,按照力学模型推导出了增力系数和输出力的计算公式,分析了各工作参数对增力效果的影响。该机构具有绿色环保,结构简单、紧凑,增力系数大等优点。     

钢球增力液压夹具的力学计算

介绍了两种应用于液(气)夹其中的钢球增力机构,推出了其理论增力系数和实际增力系数的计算公式,并对它们进行了性能比较.钢球增力机构与无杆液压缸组合而成的夹具,具有力传递效率高,结构简单,制造工艺简便的优点。     

基于液压缸的铰杆—杠杆增力双向夹紧液压夹具

介绍了两种由液压缸与双边铰杆-杠杆增力机构组成的双向夹紧液压夹具,分析了其工作原理和结构特点,并给出了理论与实际夹紧力的计算公式.其显著特点是结构简单,摩擦损失小.     

一种无杆缸-对称铰接液压增力夹具

介绍了一种新型的基于无杆液压缸与对称铰链增力机构组合而成的液压夹具的工作原理。给出了相应的力学计算公式。该系统结构紧凑，力放大效果显著。     

一种新型的流体偏心正交增力装置

介绍了一种新型的流体偏心正交增力装置的工作原理以及相应的力学计算公式。与已有的偏心夹紧机构与有杆液压缸组成的、齿轮齿条为中间驱动装置的夹紧装置相比，该装置增力效果好，能有效地降低流体系统的工作压力。     

Lubrication characteristics of dual piston ring in bent-axis type piston pumps

The bent-axis type of piston pump driven by the piston rod works by the piston rod driving the cylinder block; because of this the taper angle of the piston rod and the swivel angle between the cylinder block and the shaft are important design factors. If these factors cannot satisfy the conditions for optimum design, the friction loss between the cylinder bore and the piston increases, and the pump can fail to work under conditions of severe friction and wear. Since the piston reciprocates in the cylinder bore with high velocity, at the same time rotating on its own axis and revolving on the center of the cylinder block, a decrease of the volume efficiency is generated because of the leakage between the cylinder bore and the piston. Therefore, to prevent this, the piston ring is designed to be at the end of the piston, and the friction characteristics between the piston ring and the cylinder bore require further research due to their great influence on the performance of the piston pump. Thus, in this paper, the elastohydrodynamic lubrication (EHL) analysis of the film thickness, the pressure distribution, and the friction force, have been studied between the piston ring and the cylinder bore in the bent-axis type of piston pump. The analyzed results show that the friction force is influenced by the rotating speed and the discharge pressure.     

一种低速重载单作用液压缸

过大的径向力是影响液压缸使用寿命的重要因素。该文介绍了一种低速重载液压缸，该液压缸采用辅助支承以及将活塞杆受推杆作用的作用点移至活塞与端盖上的导向套之间，能够极大地减小活塞与活塞杆所受的径向力，从而避免导向套磨损严重、拉缸、密封损坏、内泄大、端盖处有外泄等故障的发生，提高了液压缸的使用寿命。     

基于ANSYS的可调行程液压缸的活塞杆有限元分析及优化

以可调行程液压缸的活塞杆为研究对象,针对其结构特点对液压缸整体性能的影响,利用ANSYS软件建立活塞杆的有限元模型。通过分析可调行程液压缸的工作情况,得到受力最大的工作位置,对此位置进行静力与疲劳分析,校核活塞杆的屈服强度,得到了活塞杆的应力云、变形和寿命分布云图,分析得到活塞杆的薄弱部位。根据有限元分析结果,对活塞杆进行了结构优化与改进,再对优化后的活塞杆进行分析。结果表明优化后的活塞杆特性有显著的提高。     

Dynamic behavior analysis of reciprocating compressor with subsidence fault considering flexible piston rod

Subsidence wear is inevitable in a reciprocating compressor system, but how to induce body vibration is not clear. We investigated the dynamic behavior of a reciprocating compressor system with subsidence fault considering a flexible piston rod. The flexible piston rod was modeled as a cantilever beam. The dynamic model, in which the influence of the subsidence size, variational cylinder pressure, impact effects and piston rod flexibility are taken into account, was established. Influences of the four parameters including subsidence size, vertical force of flexible piston rod, cylinder pressure and crankshaft speed were analyzed in the dynamic response. Numerical results reveal that with the change of the four parameters, the existence of subsidence fault has a significant effect on the displacement, velocity and acceleration of the crosshead in the transverse direction, but only conspicuously affects the acceleration in the longitudinal direction. In addition to cylinder pressure, the larger the values of the other three parameters, the greater the influences. The cylinder pressure is a time-varying working load. Not only the cylinder pressure but also the open/close time of the valves and change rate of the pressure all affect the dynamic behavior of the system with subsidence. Meanwhile, the change in the vertical force of the flexible piston rod has a remarkable effect on the jump position of the crosshead, but the effect of other parameters is not obvious. In addition, the changes of parameters produce obvious influences on the impact force and the impact range of the crosshead. The stability of the reciprocating compressor system was studied using Poincaré portraits method. The result shows that the system with subsidence fault has chaotic behavior.     

液压破碎锤破碎混凝土的动力学分析

液压破碎锤工作环境十分恶劣,其中活塞杆、钎杆、活塞缸体是其最易失效的零件.针对YYC300型行程反馈式液压破碎锤,利用SOLIDWORKS进行实体建模,在LS-DYNA中对活塞杆撞击钎杆、钎杆受力侵彻混凝土的过程进行了刚柔体运动、非线性接触碰撞动力学仿真,获得了液压破碎锤主要零部件—冲击缸体、钎杆、活塞杆的应力云图以及液压破碎锤的应力集中点在撞击过程中的应力变化曲线及混凝土破碎情况.依据对混凝土破碎结果的分析,可为选择液压锤型提供依据,通过对液压锤关键部位应力变化的试验研究,验证了仿真结论的正确性.     

一种钢板预弯机夹紧梁的新型液压夹紧装置

针对钢板预弯机夹紧梁快速动作时回程缸活塞杆被拉断,以及弯边时夹紧梁不能可靠夹紧钢板,提出了一种新型夹紧梁液压夹紧装置。该装置配有由蓄能器与高压小流量液压泵组成的节能型液压系统,以及能够使下夹紧梁跟随下模梁完成快速上升和快速回程的下模导向架。装置试验结果表明,两个夹紧缸同步运动误差在1 mm之内,夹紧力满足设计要求,夹紧梁运行稳定、可靠。     

Structural Design and Dynamic Characteristics of Overloaded Horizontal Servo Cylinder for Resisting Dynamic Partial Load

When an output curve force is applied to a horizontal servo cylinder with a heavy load, the piston rod bears a dynamic partial load based on the installation and load characteristics, which significantly a ects the frequency response and control accuracy of the servo cylinder. Based on this partial load, increased friction can lead to cylinder bore scu ng, leakage, lack of output power, or even system failure. In this paper, a novel asymmetric static-pressure support structure is proposed based on the principle of hydrostatic support. The radial component force of a dynamic partial load is balanced by cooperation between the support oil cushion of the variable hydraulic pressure support structure, oil cushion of the supportive force, and the damper. Adaptive control of the servo cylinder piston rod, guide sleeve, and piston, as well as the cylinder oil film friction between lubricated surfaces is achieved. In this paper, theoretical design and analysis of the traditional hydrostatic bearing structure and novel structure are presented. A hydraulic dynamic shear scissor is used as a research target to derive a structural dynamic model. Comparative simulations are performed using Matlab Simulink. Additionally, flow field analysis of the novel structure is performed, which verifies the rationality and feasibility of the proposed structure and system.     

碳化钨涂层活塞杆的研制

在往复压缩机中活塞杆的耐磨、耐蚀性的问题始终是提高产品质量的一大难题。作者研制出一种碳化钨涂层活塞杆,并经三年试车考验,效果良好。     

Experimental and numerical study of friction in an elastomeric seal for pneumatic cylinders

The behaviour of an elastomeric seal for a pneumatic cylinder piston is analysed in this work. The aim of the paper is to validate experimentally a numerical approach to evaluate seal performance, in actual working conditions.The friction force between seal and the cylinder bore is evaluated through experimental tests and numerical simulations, using a finite element model. Working conditions are simulated for different piston rod velocity and cylinder supply pressure, both in dry conditions, boundary and fluid lubrication conditions. Simulation is obtained by an iterative process that uses the friction coefficient, experimentally measured, as a function of speed and lubrication conditions. Results obtained from experimental tests and numerical simulation are compared to determine the friction force between seal and cylinder bore.