BRAKE DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a brake device suitable for intelligent operation of the braking function and suitable for miniaturization of the device. SOLUTION: An electric actuator 4 to advance/retract a friction material 3 to/from a rotary body 2 for braking consists of a magnetostrictive material 12 which is of rod-shape in which one end is abutted on the friction material 3 and the other end is locked by a friction material supporting member 10, and whose length is changed in the axial direction by the magnetostriction, and an electromagnetic coil 14 which is fixed to the friction material supporting member 10 to surround the outer circumference of the magnetostrictive material 12 and applies the magnetic field according to the applied voltage. Advancement/ retraction of the friction material 3 necessary for the braking is performed by elongation/contraction due to the magnetostriction of the magnetostrictive material 12.