基于超声减摩原理的气缸摩擦特性研究

发布时间：2018-10-26 17:22

【摘要】：气缸作为气动系统中最常见的执行机构,广泛应用于自动化生产中。然而,气缸摩擦力是对加工质量、定位精度以及对设备使用寿命产生不良影响的主要原因之一。作为一种新颖的减摩方式,超声减摩近年来受到了广泛的重视与深入的研究。本文将对橡胶—铝合金摩擦副间的超声减摩原理进行探究并将其应用于气缸减摩中,以求改善气缸的静摩擦特性。本文建立了平面接触摩擦副静摩擦力的物理模型。通过推导超声波在铝合金板上传播的振动方程,讨论了其对平面接触静摩擦力的影响。针对气缸密封圈与缸筒内壁之间的摩擦,建立了超声振动作用于缸筒外壁条件下的物理模型。通过对一定气压下密封圈形状的改变及摩擦副间接触状态变化的探讨解释了气缸在超声振动下的减摩机理。运用ANSYS对超声振动下铝合金平板与气缸的振型进行仿真。超声波激振下的铝合金平板或气缸上各点以驻波的形式在原位置附近做竖直方向的简谐振动。同时,与铝合金平板类似,在气缸上传播的机械波各波腹振动幅值相仿,分布均匀,且它们的几何中心处是驻波的波腹之一,具有最大的振动幅值。搭建橡胶/铝合金摩擦副基础试验测试系统,实现了对超声振动下的橡胶—金属摩擦副间的最大静摩擦力与极限位移的研究。橡胶与铝合金材料间的最大静摩擦力可以减小为常态下的23.1%。并且,不论是否加入超声振动,橡胶—金属摩擦副间的最大静摩擦力随着法向压力的增加而增大。增加超声振动的振幅或增大橡胶与金属板的接触面积均会减小最大静摩擦力与极限位移。创建气缸的超声减摩测试系统,通过在气缸外壁引入超声振动的方式大幅度减小了气缸的最大摩擦力与极限位移。在工况下超声振动的引入可以将气缸的最大静摩擦力减小为常态下的36.3%,将极限位移减小为常态下的25%。增大激励电压并且使作用于气缸上的超声振动频率处于谐振频率附近均可改善气缸的静摩擦特性。
[Abstract]:As the most common actuator in pneumatic system, cylinder is widely used in automatic production. However, cylinder friction is one of the main reasons for the adverse effects on machining quality, positioning accuracy and service life of equipment. As a novel antifriction method, ultrasonic friction reduction has been paid more and more attention in recent years. In this paper, the principle of ultrasonic friction reduction between rubber and aluminum alloy friction pairs is studied and applied to reduce friction of cylinders in order to improve the static friction characteristics of cylinders. In this paper, the physical model of the static friction force of plane contact friction pair is established. By deducing the vibration equation of ultrasonic wave propagation on aluminum alloy plate, the influence of ultrasonic wave on plane contact static friction is discussed. Aiming at the friction between cylinder sealing ring and cylinder inner wall, the physical model of ultrasonic vibration acting on cylinder outer wall is established. The friction reduction mechanism of cylinder under ultrasonic vibration is explained by discussing the change of seal ring shape and the contact state between friction pairs under certain pressure. The vibration modes of aluminum alloy plate and cylinder under ultrasonic vibration are simulated by ANSYS. The vertical harmonic vibration of the aluminum alloy plate or cylinder is made in the form of standing wave in the vicinity of the original position. At the same time, similar to the aluminum alloy plate, the vibration amplitude of the mechanical wave belly propagated on the cylinder is similar and the distribution is uniform, and their geometric center is one of the standing wave grooves, which has the largest vibration amplitude. A basic testing system for rubber / aluminum alloy friction pairs was built to study the maximum static friction force and ultimate displacement between rubber and metal friction pairs under ultrasonic vibration. The maximum static friction between rubber and aluminum alloy can be reduced to 23.1g under normal condition. Moreover, the maximum static friction force between rubber and metal friction pairs increases with the increase of normal pressure, regardless of whether ultrasonic vibration is added or not. Increasing the amplitude of ultrasonic vibration or increasing the contact area between rubber and metal plate can decrease the maximum static friction force and limit displacement. The ultrasonic friction reduction testing system is established. The maximum friction force and the limit displacement of the cylinder are greatly reduced by introducing ultrasonic vibration into the outside wall of the cylinder. The maximum static friction force of the cylinder can be reduced to 36.3 under normal condition and the limit displacement can be reduced to 25 under normal condition with the introduction of ultrasonic vibration. The static friction characteristics of the cylinder can be improved by increasing the excitation voltage and making the ultrasonic vibration frequency on the cylinder near the resonant frequency.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TH138.51

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