Development of gel-structured electro-rheological fluids and their application to nano positioning mechanism

电流变液是一种功能流体，其粘弹性性质随外加电场强度的不同而变化。电流变流体的性能被期望用来控制机械元件的性能，并已被应用于可变阻尼器和离合器等机械元件。然而，电流变流体的缺点是电流变颗粒的沉积，以及对密封机制的要求。电流变颗粒的沉积降低了电流变效应，导致电流变器件的稳定性较低。为了解决这些问题，本研究开发了凝胶结构电流变液(ERG)。由于凝胶的框架阻止了ER粒子从基础油中沉淀，因此成功地抑制了ER粒子从基础油中的分离和沉积。对ERG的基本特性进行了实验分析。在基本分析结果的基础上，将ERG应用于纳米定位机构，并对其性能进行了评价。首先，对ERG的组成与性能的关系进行了实验研究。实验分析表明，电场作用下ERG产生的剪应力是ERF的20~30倍。ERG也显示了ER效应的高度重复性。ERG的这些高性能表明，ERG中电流变效应的发生机制与ERF中的不同，这是粒子链形成的根源。ERG的电流变效应源于ERG表面的摩擦状态随外加电场的变化而发生的表面性质变化。在性能分析的基础上，将ERG应用于气动静压滑块夹持机构。利用ERG提出了零力夹持机构。夹紧时不会出现滑块的误动，夹紧力采用电动调节。

Electro-rheological fluids (ERF) are functional fluids whose viscoelastic properties vary with the intensity of the applied electric field. The property of ERF has been expected to control the performances of machine elements, and the ERF has been applied to machine elements such as variable dampers and clutches. However, the disadvantages of ERF are the sedimentation of ER particles and the requirement of seal mechanism. The sedimentation of ER particles reduces the ER effects, results in low stability of ER devices. To solve these problems, gel structured electro-rheological fluids (ERG) were developed in this study. The separation and sedimentation of ER particles from the base oil were successfully suppressed because the frames of gel prevent the particles from sedimentation. The basic characteristics of ERG were experimentally analyzed. On the basis of the results of the basic analysis, ERG was applied to the nano positioning mechanism and their performances were evaluated. First of all, the relation between the constituents of ERG and the performance are experimentally investigated. The experimental analysis clarified that the generated shear stress of ERG under electric field is 20〜30 times as large as that of ERF. The ERG also shows the high repeatability of ER effect. These high performances of ERG suggest that the occurrence mechanism of ER effect in ERG is different from that in ERF, which originate the particle chain formation. The ER effect of ERG originates the change of frictional condition on ERG surface due to the variation of surface properties according to the applied electric field. Based on the performance analysis, ERG was applied to the clamp mechanism for aero-static slider. The zero force clamping mechanism was proposed by using the ERG. The error movement of slider in clamping does not occur and the clamping force is adjusted electrically.