Electrical generator or motor structure – Dynamoelectric – Rotary
Reexamination Certificate
1991-05-17
2004-03-02
Tamai, Karl (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
C310S244000, C310S248000
Reexamination Certificate
active
06700290
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an electric motor and more particularly to brush gear for an electric motor.
Brush gear in small electric motors, particular fractional horsepower permanent magnet direct current (PMDC) motors, typically comprises a carbon brush which is carried on an end of a resilient, electrically conducting arm—the brushleaf. The brushleaf is arranged to bias the brush against a commutator on the motor shaft. Typically the brush gear is mounted in an end cap which carries a bearing for the motor shaft and forms a structural part of the motor assembly.
In low voltage applications, the total resistance of the motor becomes more and more determined by the interface resistance between the brushes and the commutator. As the motor resistance determines the maximum power range within which the motor can operate, reducing the brush/commutator interface resistance is very desirable.
BRIEF SUMMARY OF THE INVENTION
According to the invention there is provided an electric motor brush assembly comprising resilient electrically conductive support means arranged to carry two or more separately formed brush bodies axially displaced with respect to a longitudinal axis of the motor and connected electrically in parallel.
The support means normally comprises a separate arm for each brush body.
The separate arms may be arranged to have different natural resonance frequencies of oscillation.
The brush bodies may have different sizes and/or different physical densities.
A fractional horsepower direct current electric motor may be provided having a brush assembly comprising resilient electrically conductive support means arranged to carry two or more separately formed brush bodies axially displaced with respect to a longitudinal axis of the motor and connected electrically in parallel.
REFERENCES:
patent: 421967 (1890-02-01), Pfatscher
patent: 2760094 (1956-08-01), Edmunson
patent: 3041118 (1962-06-01), Campbell
patent: 3141985 (1964-07-01), Martin
patent: 3171997 (1965-03-01), Hammer
patent: 3619677 (1971-11-01), Hargreaves
patent: 3671791 (1972-06-01), Muller
patent: 4037125 (1977-07-01), Aoki
patent: 4086510 (1978-04-01), Watanabe
patent: 4163916 (1979-08-01), Kobayashi
patent: 4195242 (1980-03-01), Mabuchi
patent: 4431933 (1984-02-01), Mabuchi
patent: 4705978 (1987-11-01), Mabuchi
patent: 4728835 (1988-03-01), Baines
patent: 4983872 (1991-01-01), Strobl
patent: 1111527 (1968-05-01), None
patent: 55-83851 (1980-06-01), None
patent: 59-30672 (1984-02-01), None
patent: 59-75748 (1984-05-01), None
patent: 59-230450 (1984-12-01), None
patent: 60-141663 (1985-09-01), None
patent: 62-293953 (1987-12-01), None
patent: 63-77457 (1988-05-01), None
CRC Handbook of Chemistry and Physics, 62nd Edition, pp. B89 and B97, 1982.*
Translation of Japanese Office Action dated Sep. 8, 1998.
Birch & Stewart Kolasch & Birch, LLP
Johnson Electric S.A.
Tamai Karl
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