Case for electric motor brushes comprising cooling fins

Details Case for electric motor brushes comprising cooling fins Case for electric motor brushes comprising cooling fins

1998-05-28

2001-05-08

Tamai, Karl (Department: 2834)

Electrical generator or motor structure

Dynamoelectric

Rotary

C310S064000

Reexamination Certificate

active

06229242

ABSTRACT:

FIELD OF THE INVENTION
The invention relates to cases for electric motor brushes to sub-assemblies for electric motors comprising such cases and to electric motors comprising such cases.
BACKGROUND OF THE INVENTION
There is known, from French patent application number 2 699 749A, a brush case made by bending a metal blank defining a housing for guiding a brush in a sliding manner, and comprising cooling fins extending to the top of the case. The fins are shaped and disposed to have a large contact surface with the case and to offer a large exchange surface by convection with the ambient air. However, this case has the drawback that the bending of the blank for the manufacture of the case is complicated to perform. Moreover, the possibilities for shaping and arranging the fins remain limited and do not enable good cooling performances to be obtained.
One object of the invention is to provide a case which is easier to manufacture and which offers more possibilities and at least one cooling fin, arranged with improved cooling performance.
SUMMARY OF THE INVENTION
In accordance with the, there is provided a case for an electric motor brush defining a housing for a brush and comprising a cooling fin, a flat metal base plate and a cover plate, the base plate and cover plate being formed by separate pieces defining the housing.
Thus, the cover plate and the base plate are produced separately, which facilitates the manufacture of the case. Moreover, this separate design offers great freedom as to shape and arrangement of the fin to optimize the cooling performances.
Advantageously, the base plate has a dimension in the transversal direction perpendicular to an axial direction of the cover plate which is at least equal to twice a larger dimension of the cover plate in the transverse direction.
Thus the base plate itself offers a large heat exchange surface by convection with the ambient air.
The fin advantageously extends from the base plate.
The fin advantageously extends in a plane parallel to an axial direction of the cover plate.
The fin advantageously extends in a plane perpendicular to the base plate.
The case advantageously comprising a stop lug fixed to the base plate and extending in a plane that is not parallel to an axial direction of the cover plate. Thus this lug offers a stop to secure an end of a band spring coiled thereon ensuring the return of the brush towards a commutator of the motor.
The stop lug advantageously has two plane faces not parallel to an axial direction of the cover plate and forming an obtuse angle between such faces. Thus, the lug ensures good positioning of the coiled end of the band spring.
The stop lug is advantageously in a single piece with the base plate.
The cover plate advantageously comprises two lateral walls suitable for extending perpendicularly to the base plate and having cut-outs extending from one axial end of the cover plate.
Thus, these cut-outs allow the passage of the band spring.
Also provided in accordance with the invention is a for an electric motor comprising a case, a brush suitable to be received slidingly in the case and a band spring for the return of the brush, the case comprises a cooling fin, the a flat metal base plate and a cover plate, the base plate and cover plate being formed by separate pieces defining the housing.
There may be provided a brush unit comprising a case and a brush, or a plate bearing several brush units of this type.
Furthermore according to the invention an electric motor is provided comprising a case which comprises a cooling fin, a flat metal base plate and a cover plate, the base plate and cover plate being formed by separate pieces defining the housing.
Other characteristics and advantages of the invention will become further apparent in the following description of a preferred embodiment given by way of a non-restrictive example.


REFERENCES:
patent: 1469720 (1923-10-01), Dorsey
patent: 2275613 (1942-03-01), Cullin
patent: 3127533 (1964-03-01), Gardner, Jr.
patent: 4785214 (1988-11-01), Mummert
patent: 4990811 (1991-02-01), Nakata et al.
patent: 5397952 (1995-03-01), Decker et al.
patent: 5495134 (1996-02-01), Rosenblum
patent: 5949175 (1999-09-01), Cummins
patent: 0 418 135 (1991-03-01), None
patent: 0 615 316 (1994-09-01), None
patent: 2 427 711 (1979-12-01), None
patent: 2 459 571 (1981-01-01), None
patent: 2486323 (1982-01-01), None
patent: 2 699 749 (1994-06-01), None
patent: 2 022 932 (1979-12-01), None
patent: 2 057 198 (1981-03-01), None
patent: 2 191 346 (1987-12-01), None
patent: 1-97151 (1989-04-01), None
patent: 52-122803 (1997-10-01), None
French Search Report dated Feb. 20, 1998.

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