ELECTRIC ACTUATOR AND A MOTOR USED THEREIN

• US 20080116758A1
• Filed: 12/28/2007
• Published: 05/22/2008
• Est. Priority Date: 04/26/2005
• Status: Abandoned Application

• Current Assignee: Igarashi Electric Works Ltd., Mitsui Mining and Smelting Company Limited
• Original Assignee: Igarashi Electric Works Ltd., Mitsui Mining and Smelting Company Limited
• Inventors: TANAKA, Katuyuki, MIZUKOSHI, Yusuke, SESITA, Naoto, YOKOMORI, Kazuhito, KURIHARA, Hiroyuki, WATANABE, Yoshihisa
• Application Number:
  US11/966,089
• Publication Number:
  US 20080116758A1
• Time in Patent Office: Days
• US Class Current: 310/154.03
• CPC Class Codes: H02K 15/14 Casings; Enclosures; Supports
• CPC Class Codes: H02K 2213/09 Machines characterised by the presence of elements which are subject to variation, e.g. adjustable bearings, reconfigurable windings, variable pitch ventilators
• CPC Class Codes: H02K 5/10 with arrangements for protection from ingress, e.g. water or fingers
• CPC Class Codes: H02K 5/15 Mounting arrangements for bearing-shields or end plates
• CPC Class Codes: H02K 5/24 specially adapted for suppression or reduction of noise or vibrations
• CPC Class Codes: H02K 7/081 specially adapted for worm gear drives H02K7/09 takes precedence
• CPC Class Codes: H02K 7/1166 comprising worm and worm-wheel structural association with bearings specially adapted for worm gear drives H02K7/081
• CPC Class Codes: Y10T 74/19828 Worm

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.

Claims

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.