GB2207293A

GB2207293A - Brush gear for an electric motor

Info

Publication number: GB2207293A
Application number: GB08716517A
Authority: GB
Inventors: Chin Hung Li
Original assignee: Johnson Electric Industrial Manufactory Ltd
Current assignee: Johnson Electric Industrial Manufactory Ltd
Priority date: 1987-07-14
Filing date: 1987-07-14
Publication date: 1989-01-25
Also published as: DE8808999U1; GB8716517D0; CN2045909U; JPS6416160U

Abstract

Brush arm 10 comprises two electrically conductive strips forming, respectively, a terminal part (12) and a more resilient brush supporting part (13) secured together in overlapping relationship by at least one projection which extends laterally from the strip (12) and which is bent and crimped about the strip (13). The brush arm support (11) has a groove (16) in which the overlapping portions of the strips are mounted as a loose fit and a recess (18) in one side of the groove for receiving the crimping portions of the projection (14) as a force fit. The crimping portions are held captive between facing walls (17) of the recess to prevent lengthwise movement of the brush arm. <IMAGE>

Description

Brush gear for an electric motor This invention relates to brush gear for an electric motor and to an electric motor equipped with such brush gear.

According to the invention, there is provided brush gear for an electric motor, comprising a brush arm and means supporting the brush arm, tL - brush arm comprising two electrically conductixX strips forming, respectively, a terminal part and a more resilient brush supporting part, the two strips being secured together in overlapping relatioiship by at least one projection which extends laterall: from one of the strips and which is bent and crimped about the other strip, and the means supporting the brush arm having a recess in which a crimping portion of the or each projection is located, the crimping portion or portions being engaged between two waLls of the recess which walls extend transversel or the overlapping portions of the two strips.

With this arrangement the brush arm is held captive against lengthwise movement and this has the advantage that a brush on the brush supporting part of t arm is accurately positioned relative to the brus- arm supporting means, which may be provided, for example, on an end cap of the motor.

The invention will now be more particularly desc bed, by way of example, with reference to the acco anying drawings, in which: Fig 1 is a fragmentary plan view of one embodiment of k sh gear according to the invention, and Figi 2 is a perspective view of the brush arm of Fig 1.

Refe ng now to the drawings, the brush gear com ses two brush arms 10 (only one of which is shov and a brush arm support 11, e.g. a plastics end -s of a p.m.d.c. motor.

The crush arm 10 comprises two electrically conc tive metal strips 12 and 13 forming resp lively, a terminal part and a brush supporting par. The strips 12 and 13 are of different metals, the trip 12 being of a metal to which an external conn -ion can be readily soldered, e.g. brass, and the strip 13 being of a more resilient metal, e.g.

beryllium copper or nickel silver.

The strips 12 and 13 are secured together in face to face overlapping relationship by two projections 14 which extend from opposite edges of the strip 12 and which are bent and crimped about the strip 13, the two projections 14 being of identical dimensions and being aligned in a direction perpendicular to the longitudinal extent of the strip 12.

The strip 12 has a through hole 19 for receiving an external connection and the strip 13 supports a carbon brush 15 in conventional manner at its end distal from the strip 12.

The overlapping portions of the two strips 12 and 13 are mounted as a loose fit in a groove 16 provided in the brush arm support 11 and the crimping portions of the projections 14 are mounted as a force fit between facing walls 17 of a recess 18 in one side of the groove 16. The engagement between the walls 17 and the crimping portions of the projections 14 holds the brush arm 10 captive against lengthwise movement and wall 20 of the groove 16 supports the brush arm 10 against movement in the direction of arrow A in Figure 1 to ensure that the crimping portions do not come out of the recess 18.

The above embodiment is given by way of example only and various modifications will be apparent to persons skilled in the art without departing from the scope of the invention defined by the appended claims. For example, there may be only one crimping portion.

However, in this case it will be preferable for the single crimping portion to overlie the strip 13 to a greater extent than do each of the crimping portions shown in the drawings. Furthermore, the or each crimping portion could be replaced by two or more smaller portions spaced apart in the direction of the longitudinal extent of the brush arm.

Claims

1. Brush gear for an electric motor, comprising a brush arm and means supporting the brush arm, the brush arm comprising two electrically conductive strips forming, respectively, a terminal part and a more resilient brush supporting part, the two strips being secured together in overlapping relationship by at least one projection which extends laterally from one of the strips and which is bent and crimped about the other strip, and the means supporting the brush arm having a recess in which a crimping portion of the or each projection is located, the crimping portion or portions being engaged between two walls of the recess which walls extend transversely of the overlapping portions of the two strips.

2. Brush gear as claimed in claim 1, wherein the overlapping portions of the two strips are received in a groove in the brush arm supporting means and the recess is provided in one side of the groove.

3. Brush gear as claimed in claim 1 or claim 2, wherein said one strip has two bent and crimped projections, one extending from one edge of said one strip and the other extending from the opposite edge of said one strip.

4. Brush gear as claimed in any one of claims 1 to 3, wherein said one strip is the terminal part.

5. Brush gear as claimed in any one of claims 1 to 4, comprising two brush arms and two recesses in the brush arm supporting means in which the crimping portion or portions of the two brush arms are respectively located.

6. Brush gear as claimed in any one of the preceding claims, wherein the brush arm supporting means is provided on an end cap of an electric motor.

7. Brush gear for an electric motor, substantially as hereinbefore described with reference to the accompanying drawings.

8. An electric motor including brush gear as claimed in any one of the preceding claims.