Contribution aux microsystèmes magnétiques : Micromoteur asynchrone à palier magnétique
Important progress in microelectromechanical systems (MEMS) have recently been reported and a special effort concems micromotors and microactuators. Even if electrostatic micromotors were firstly studied, the scientific community has been recently attracted to magnetic microactuators. However, little attention has been paid to induction micromotors, because its manufacturing is supposed to be tridimensional, and the forces generated are considered to smaU to even reach the movement. Furthermore, scale reduction in microsystems leads to an important increase in relative friction forces, impairing (even preventing) mechanical movement. With the intention to lessen friction losses in micromotors, miniaturised permanent magnet bearings are studied and analysed, and several prototypes are presented. In order to validate new motorisation approaches in millimetre-size devices, a first planar induction micromotor, 0 18 mm x h 2 mm, was built. It inc1udes a passive, permanent magnet suspension. This micromotor develops a torque of 1.2 flNm and reaches 4500 rpm.