Electrical generator or motor structure – Dynamoelectric – Rotary
Reexamination Certificate
1999-02-01
2001-06-05
Nguyen, Tran (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
C310S235000, C310S237000
Reexamination Certificate
active
06242838
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a commutator composed of carbon segments, particularly a commutator of a fuel injection pump motor, and to a method of manufacturing the above commutator.
2. Description of the Related Art
A commutator composed of a plurality of carbon segments is disclosed in U.S. Pat. No. 5,175,463. The carbon segments of the shaped commutator are insulated from one another by grooves. The commutator has a plurality of terminal members disposed in parallel with the rear surface of the carbon segments to be connected to the carbon segments by brazing filler metal or solder. The surfaces of the carbon segments to be connected to the terminal members are plated with metal to ensure the connection.
However, when the terminal members are connected to leads extending from armature windings by fusing or the like, fusing heat is conducted through comparatively short heat passages of the terminal members to the brazing filler. This heat may melt the brazing filler to short-circuit the carbon segments.
SUMMARY OF THE INVENTION
A main object of the invention is to provide an improved commutator segment which is free from short-circuiting of the commutator segments when it is assembled into a motor.
Another object of the invention is to provide a commutator that has comparatively long heat passages from lead-connecting portions of terminal members to portions thereof soldered to contact members of commutator segments.
Another object of the invention is to provide an improved electric motor which can be used in corrosive circumstances such as used in fuel.
Another object of the invention is to provide a method of manufacturing such commutator segments easily at low production cost.
A main feature of the invention is a commutator that includes a contact unit having a flat brush-contact surface and a connection surface, a base member made of insulation material and a terminal unit. The contact unit has a plurality of commutator segments, and the terminal unit has a plurality of conductive terminal members. The base member supports the commutator segments and insulates the same from one another. The commutator also has an electrical connection structure having a set of a convex member and a concave member and a plurality of connection members disposed between the convex member and concave member.
Preferably, the convex member has a plurality of projections axially extending from the contact unit, and the concave member has a portion of the terminal unit engaged with the projections. The contact unit and the terminal unit are spaced apart from each other except the connection structure.
An insulation spacer can be disposed between the contact unit and the terminal unit. This structure can simplify molding process of the base member. The electrical connection structure can include a rise member disposed between the contact unit and the terminal unit to hold the connection member when the connection members are melted.
Another main feature of the invention is a method of manufacturing a commutator that includes a contact unit having a flat brush-contact surface and a connection surface, a base member made of insulation material and a terminal unit.
The method is composed of the steps of forming a solid carbon disk having a plurality of axially extending arc-shaped projections, plating the peripheral surfaces of the arc-shaped projections with conductive metal, forming a brass ring member having a plurality of through holes, assembling the solid carbon and the brass ring so that the arc-shaped projections are disposed into the through holes respectively to have appropriate molding spaces between the solid carbon disk and the brass ring, inserting solid solders in connection spaces defined the through holes and the inside surface of the arc-shaped projections, heating the solders to melt in the connection spaces, filling resinous insulation material in the molding spaces, and cutting the solid carbon disk and the ring member to provide the plurality of commutator segment and the plurality of terminal members.
REFERENCES:
patent: 5175463 (1992-12-01), Farago et al.
patent: 5400496 (1995-03-01), Kemmner et al.
patent: 5629576 (1997-05-01), Shimoyama
patent: 5637944 (1997-06-01), Shimoyama
patent: 5793140 (1998-08-01), Tuckey
Ebihara Yoshio
Ito Motoya
Kiyose Kenzo
Sakamoto Yoshitsugu
Yamashita Keiichi
Denso Corporation
Nguyen Tran
Nixon & Vanderhye P.C.
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