DE8808999U1 - Brush current collector for an electric motor - Google Patents

Description

The present application claims priority from British application No. 8716517 filed on 14 July 1987 .

The invention relates to a brush current collector for an electric motor and to an electric motor equipped with such a brush current collector.

The object of the invention is to design a brush current collector in such a way that the brush arm is secured against longitudinal movement and thus the brush is exactly positioned in a brush holding part of the arm relative to the brush arm holder.

This object is achieved according to the invention in an article according to the preamble of claim 1 by its characterizing features.

For this purpose, the brush current collector for an electric motor according to the invention has a brush arm and a holder for the brush arm, the latter having two electrically conductive strips, each forming a connecting part and a brush holding part with a higher elasticity. The two strips are fastened or connected to one another in an overlapping manner by at least one projection which extends from one strip in a lateral direction and is bent around the other strip and crimped. The holder for the brush arm has a recess in which a crimped section of the projection or each of the projections is received, a pair of opposite edges of the crimped area or the crimped

extending transversely to the overlapping portions of the two strips.

With this arrangement, the brush arm is held against displacement or movement in the longitudinal direction, which has the advantage that the brush is correctly positioned on the brush holding part of the arm relative to the brush arm holder, which can be provided, for example, on the end cap of the motor.

Advantageous embodiments and further developments of the invention are characterized in the subclaims.

The following is a description of a preferred embodiment based on the drawings.

It shows:

Figure 1 is a fragmentary plan view of a brush current collector according to the invention;

Figure 2 is a perspective view of the brush arm of Figure 1.

The brush current collector according to the present invention shown in the drawings comprises two brush arms 10 (only one of which is shown) and a brush arm holder 11, for example the plastic end cap of a permanent magnet DC motor.

The brush arm 10 has two electrically conductive metal strips 12 and 13, each of which forms a connection part and a brush holding part. The strips 12 and 13 are made of different metals, i.e. the strip 12 consists of a metal to which an external connection can be soldered, for example brass, while the strip 13 consists of a more elastic or rigid metal.

ker resilient metal such as beryllium copper or nickel silver.

The strips 12 and 13 extend colinearly and are connected to one another in a broadside-to-broadside manner by two projections 14 extending from the opposite edges of the strip 12 and bent and crimped around the strip 13, the two projections 14 having equal 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. The strip 13 carries a carbon brush 15 in the usual manner at its end remote from the strip 12.

The overlapping portions of the two strips 12 and 13 are secured by a clearance fit in a recess 16 formed in the brush arm housing 11, while the crimped portions of the projections 14 are mounted by an interference fit between the facing walls 17 of a recess 18 in one side of the recess 16. The engagement between the walls 17 and the crimped portions of the projections 14 holds the brush arm 10 captive against longitudinal movement, and the wall 20 of the recess 16 supports the brush arm 10 against movement in the direction of arrow A in Figure 1 and ensures that the crimped portions do not come out of the recess 18.

The above invention has been described with reference to a preferred embodiment. Various modifications are possible without departing from the scope of the invention as set out in the claims. For example

only one crimping section could be provided. In such a case, however, the single crimping section would have to overlap the strip 13 to a greater extent than is the case with the two crimping sections shown in the drawings. Furthermore, the crimping section or each of the crimping sections could be replaced by two or more smaller sections spaced apart from one another in the direction of the longitudinal extension of the brush arm.

Claims (6)

i &iacgr; · · · ♦ JOHNSON ELECTRIC INDUSTRIAL MANUFACTORY LIMITED Johnson Building 14-16 Lee Chung Street Chaiwan, Hong Kong F 13.529 fl/wa BRISTLE CURRENT COLLECTOR FOR AN ELECTRIC MOTOR Claims 1. Brush current collector for an electric motor with a brush arm and a brush arm holder, characterized in that the brush arm has two electrically conductive strips (12) and ⁽ 13), each forming a connection part and a brush holding part with a higher elasticity, the two strips (12) and (13) being fastened to one another or connected to one another in an overlapping manner by at least one projection (14) leading laterally from one of the strips and bent around the other strip and crimped, and that the brush arm holder (11) has a recess (18) in which the crimping area of the projection or each of the projections (14) is received, a pair of opposite edges of the crimping area or the crimping areas being between the two walls (17) of the recess (18) are received in an attacking manner
extend transversely to the overlapping sections of the two strips (12) and (13). 2. Brush current collector according to claim 1, characterized in that the overlapping regions of the two strips (12) and (13) are received in a recess (16) formed in the brush arm holder (11) and the recess (18) is provided in one side of the recess (16). ' M ii \ i aj··, &khgr;. 3. Brush current collector according to one of claims 1 or 2, characterized in ' that one of the two strips (12 or 13) has two bent and crimped projections (14), one of which extends from one edge of said strip and the other of which extends from the opposite edge of said strip. 4. Brush current collector according to one of claims 1 to 3, characterized in that this one strip (12) having the projections forms the connecting part. 5. Brush current collector according to one of claims 1 to 4, characterized in that two recesses (18) are provided in the brush arm holder (11), in which the crimping area or areas of two brush arms are respectively received. 6. Brush current collector according to one of claims 1 to 5, characterized in that the brush arm holder (H) is designed as an end cap of the electric motor.