Brush holder structure in electric motor

• US 5,159,221 A
• Filed: 08/31/1990
• Issued: 10/27/1992
• Est. Priority Date: 08/31/1989
• Status: Expired due to Term

• Current Assignee: Mitsuba Corporation
• Original Assignee: Mitsuba Electric Manufacturing Company Limited
• Inventors: Abe, Isao, Miyazaki, Masami
• Primary Examiner(s): SKUDY, ROBERT
• Application Number:
  US07/575,831
• Time in Patent Office: 788 Days
• Field of Search: 310/83, 310/239, 310/242, 310/245, 310/247, 310/249, 310/89, 310/43
• US Class Current: 310/239
• CPC Class Codes: H01R 39/40 enabling brush movement within holder during current collection
• CPC Class Codes: H01R 43/24 Assembling by moulding on contact members
• CPC Class Codes: H02K 5/148 Slidably supported brushes

Abstract

A brush holder structure in an electric motor in which brush holders for housing brushes held in slidable contact with a commutator provided on a rotor shaft and an end bracket for rotatably supporting the rotor shaft are both integrally molded with a gear frame for housing and supporting a worm gear mechanism. The worm gear mechanism includes a worm formed around the distal end portion of the rotor shaft and a worm wheel held in mesh with the worm. A lead-out groove for leading out a pig tail extended from each brush is formed in a proximal end side wall of each brush holder with respect to the rotor shaft, and a receiver for receiving resilient spring fitted in each brush holder to press each brush against a commutator is disposed between two proxiamal and distal end side walls of each brush holder. The receiver extends in the axial direction of the rotor shaft, and is set to have its width not exceeding the width of the lead-out groove in the circumferential direction of the rotor shaft. The brush holders having the receiver can be simply molded by setting first and second molds in butt relationship against a main mold.

Claims

1. A brush holder structure suitable for use in an electric motor in which an end bracket is integrally molded with a gear frame, the brush holder structure for housing at least one brush held in suitable contact with a commutator, the end bracket rotatably supporting a rotor shaft of the motor and the gear frame housing and supporting a worm gear mechanism which includes a worm formed around a distal end portion of the rotor shaft and a worm wheel held in mesh with the worm, the brush holder structure comprising a plurality of brush holders integrally molded with the molded end bracket, each brush holder of said plurality of brush holders comprising:

(i) a proximal end side wall having a lead-out groove for leading out therethrough a pig tail, and

(ii) a spring receiver for receiving a resilient means fitted in said each rush holder, said spring receiver being disposed between the proximal each side wall and a distal end side wall of said each brush holder and extending in a direction parallel to an axial direction of the rotor shaft, wherein

said spring receiver has a width in a direction circumferential to the rotor shaft equal to or less than a width of the lead-out groove in the direction circumferential to the rotor shaft.

2. The brush holder structure of claim 1, further comprising:

a brush housed in said each brush holder; and

said resilient means for resiliently urging said brush against the commutator.

3. The brush holder of claim 2, wherein said resilient means comprises a spring disposed within said each brush holder.