Electric actuator and a motor used therein

Abstract

A motor comprises a rotor fixed to a shaft and a stator comprising a permanent magnet on the inner circumferential surface of a motor casing. The shaft extends from the opening end of the motor casing and has a worm wheel in a gear casing. The end face of the gear casing has an annular projection. The motor casing has an outward flange at the opening end. When the motor casing is connected with the gear casing, an elastic O-ring is fitted between a space formed by the outer circumferential surface of the annular projection, an outer vertical seat face of the gear casing and a corner of the outward flange thereby achieving suitable alignment of the motor casing with the gear casing. The permanent magnet is made of Nd magnet which is pressingly fitted on the inner circumferential surface of the motor casing.

1 . An electric motor comprising:
 a motor casing having an inner circumferential surface;   a shaft axially extending in the casing;   a rotor fixed to the shaft; and   a stator comprising a permanent magnet pressingly fitted on the inner circumferential surface of the motor casing, said stator facing and surrounding the rotor, said permanent magnet being made of Nd—Fe—B magnet having an inner circumferential surface on which a plurality of − and S-poles are alternately spaced equally.   
   
   
       2 . An electric motor as claimed in clam  1  wherein an external diameter of the permanent magnet is slightly larger than an internal diameter of the motor casing to achieve tight-fitting of the magnet on the inner circumferential surface of the motor casing with heating.