Microvalves Using Functional Fluids

点击翻译按钮获取中文摘要

To realize high power micromachines using fluid power, two kinds of microvalves using functional fluids such as ER (electro-rheological) fluid and magnetic fluid are developed. ER fluid has viscosity controlled by the applied electric field and magnetic fluid is pulled by the applied magnetic field.1. Fabrication of a microvalve using ER fluid : A large model consisting of 12 stacked parallel plate electrodes are fabricated. It is ascertained through experiments that the pressure is linearly controlled by the applied electric field strength independent of flowrate and that the band width is 30Hz. Also a rheological equation for ER fluid is derived. Based on the equation, a 3-port micro ER valve with 12mm*12mm*12mm in size is fabricated. Control pressure range of 0.4MPa is realized with electric field strength of 5kV/mm. Furthermore, a servo system for a 1 DOF miniature manipulator is constructed.2. Fabrication of a microvalve using magnetic fluid : A large model of stop valve is fabric … More ated and it is experimentally ascertained that the allowable pressure is in proportion to electromagnet current, intensity of magnetization of magnetic fluid and the number of serially connected valves. Also flow control characteristics are realized by using a magnetic pole with V-shaped groove. Next, to miniaturize the electromagnet, a micro switching valve using permanent magnet is proposed. A valve with 20mm*20mm*20mm in size is fabricated and the flow channel switching with 8kPa in pressure and 7Hz in frequency is experimentally verified. Furthermore, to establish and optimum design method, numerical analysis of shape of magnetic fluid in flow and magnetic field is investigated.3. Application to an in-pipe mobile micromachine : A micro ER valve which has better performance than the other is designed in cylindrical shape with 9.8mm in diameter and applied to an in-pipe mobile micromachine for pipes with 14mm in diameter. Traveling velocity of 0.9mm/s is realized and the feasibility of the proposed valve is proved. Less