Electrical generator or motor structure – Dynamoelectric – Rotary
Utility Patent
1999-11-02
2001-01-02
Ramirez, Nestor (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
C310S105000, C192S084950
Utility Patent
active
06169347
ABSTRACT:
CROSS REFERENCE TO RELATED APPLICATION
This application is based on and incorporates herein by reference Japanese Patent Application No. Hei. 10-317984 filed on Nov. 9, 1998.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an electromagnetic clutch suitable for use in a compressor of an automotive air conditioning system.
2. Description of Related Art
JP-U-1-131028 and JP-U-2-54928 disclose an electromagnetic clutch in which an electromagnetic coil is provided in a rotor.
In such an electromagnetic clutch, an electric current supplied to the electromagnetic coil is large, thereby increasing a surge voltage (reverse voltage) which is induced when the clutch is deenergized. Thus, it is necessary to connect a surge voltage absorption element such as diode in parallel with the electromagnetic coil. For example, JP-A-10-176726 discloses a diode connected in parallel with an electromagnetic coil.
However, in JP-A-10-176726, the electromagnetic coil is fixed in a stator. An installation portion into which the diode is installed is integrally formed in a bobbin around which the coil is wound, and axially protrudes toward the outside of the stator. The starting point and end point of the coil are electrically connected to the diode in the installation portion.
This layout, disclosed in JP-A-10-176726 and used for an electromagnetic clutch with a fixed coil cannot be applied to an electromagnetic clutch with a rotating coil. When the layout is applied to a rotating coil clutch, the axially protruding installation portion must be formed at the outer surface of the rotor in which the electromagnetic coil is provided. In a rotating coil clutch, the protruding installation portion will also rotate, and cannot avoid contacting a compressor housing around the installation portion.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a rotating coil clutch in which a surge voltage absorbing element is provided without increasing an axial dimension thereof.
According to a first aspect of the present invention, a slip-ring rotating with a rotor is attached in the rotor. A brush supplying electric current to the slip-ring is supported by a brush supporter fixed to a fixed member. A surge voltage absorbing element is disposed in the brush supporter.
In this way, as the surge voltage absorbing element is disposed in the brush supporter, it is not necessary to form an axial protrusion portion for installing the surge voltage absorbing element. Thus, the surge voltage absorbing element can be provided without increasing the axial dimension of the electromagnetic clutch, thereby avoiding enlargement of the electromagnetic clutch and the device it is coupled to.
According to a second aspect of the present invention, a surge voltage absorbing element is installed in a support for the slip-ring. As a result, similarly to the first aspect of the present invention, it is not necessary to form an axial protrusion portion for installing the surge voltage absorbing element. Thus, the surge voltage absorbing element can be provided without increasing the axial dimension of the electromagnetic clutch, thereby avoiding enlargement of the electromagnetic clutch and the device it is coupled to.
According to a third aspect of the present invention, a surge voltage absorbing element is disposed abutting an electromagnetic coil in a rotor. As a result, similar to the first and second aspects of the present invention, it is not necessary to form an axial protrusion portion for installing the surge voltage absorbing element. Thus, the surge voltage absorbing element can be provided without increasing the axial dimension of the electromagnetic clutch, thereby avoiding enlargement of the electromagnetic clutch and the device it is coupled to. Additionally, since the surge voltage absorbing element is placed near the electromagnetic coil, the surge voltage absorbing element can be directly connected to both ends of the electromagnetic coil.
REFERENCES:
patent: 4295553 (1981-10-01), Sayo et al.
patent: 4347453 (1982-08-01), Gaus
patent: 4404488 (1983-09-01), Herr
patent: 4476410 (1984-10-01), Wolcott
patent: 4649305 (1987-03-01), Morrill
patent: 4649307 (1987-03-01), Bech
patent: 4770061 (1988-09-01), Martinez
patent: 5306974 (1994-04-01), Bates
patent: 5691590 (1997-11-01), Kawai et al.
patent: 5997666 (1999-11-01), Horski et al.
patent: 6012563 (2000-01-01), Aoki et al.
patent: 1-131028 (1989-09-01), None
patent: 2-54928 (1990-04-01), None
patent: 10-176726 (1998-06-01), None
Aoki Yuuichi
Ohguchi Junichi
Sakamoto Hiroyasu
Denso Corporation
Pillsbury Madison & Sutro LLP
Ramirez Nestor
Waks Joseph
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