Abstract
MR (Magneto-Rheological) fluid is a functional fluid whose apparent viscosity is controlled by the applied magnetic field intensity. A valve using MR fluid called the MR valve features simple structure without moving parts. This paper improves the response of the micro MR vale that applies magnetic field to the MR fluid through a thermo-control magnetic circuit composed of a permanent magnet, a thermosensitive ferrite and a Peltier element. First, a thermo-control magnetic circuit that concentrates the thermal input to the thermosensitive ferrite is proposed. The characteristics of the magnetic circuit between magnetic field intensity and temperature of the thermosensitive ferrite are experimentally investigated and the improvement of the response is confirmed. Second, a 3-port micro MR valve is designed and fubricated. The characteristics of the 3-port micro MR valve among load pressure, flow rate and temperature are experimentally clarified.
