Magnetic fluid devices for driving micro machines

This paper is concerned with the development of micro magnetic fluid devices for driving micro machines. Two kinds of new magnetic fluid devices are proposed. One is the magnetic fluid motor, and another one is reciprocating actuator. These micro devices are composed of a permanent NdFeB magnet and kerosene-based magnetic fluid HC-50. They are characterized by wireless operation with alternating magnetic field. The driving characteristics of micro magnetic fluid devices are examined by using a digital high speed video camera system. The rotary motion of the micro magnetic fluid motor shows the existence of rotational regions and irrotational regions in frequencies of external magnetic field. The amplitude of reciprocating actuator depends on the frequency of magnetic field. The effect of the volume of magnetic fluid adsorbed to the permanent magnet is also revealed experimentally.