Carbon commutator
First Claim
1. A carbon-segment commutator assembly for an electric motor, the commutator assembly comprising:
- an annular array of at least two circumferentially spaced conductor sections arranged around a rotational axis;
an annular array of at least two circumferentially-spaced carbon segments formed of a conductive carbon composition, each carbon segment overmolded onto at least one surface of a corresponding one of the conductor sections forming an annular array of commutator sectors, the annular array of commutator sectors including an axial top end surface, an axial base end surface and an inner circumferential surface, the annular array of carbon segments defining a segmented composite outer-circumferential commutating surface of the commutator; and
an overmolded insulator hub comprising a hub insulator material disposed on the axial top end, base end and inner circumferential surfaces of the annular array of commutator sectors to mechanically interlock the commutator sectors, the overmolded insulator hub including a central axial aperture disposed concentrically within the inner circumferential surface of the commutator sectors.
1 Assignment
0 Petitions
Accused Products
Abstract
A carbon-segment face commutator assembly for an electric motor includes an annular array of copper conductor sections stamped from a single copper blank. The annular array is overmolded with an electrical-conducting resin-bonded carbon composition that mechanically interlocks the conductor sections and defines a circular commutating surface. During overmolding, radial grooves are formed in a bottom surface of the carbon overmold opposite the commutating surface. An annular hub is then formed by overmolding an insulator material around and under the carbon overmold and the conductor section array. The hub insulator material flows into the radial grooves of the carbon overmold and leaves only the circular-commutating surface exposed. The carbon overmold is formed into an annular array of eight electrically-isolated carbon segments by machining radial slots inward from the commutating surface of the carbon overmold to the underlying radial grooves. The slots are cut slightly into the insulator material occupying the radial grooves to ensure that the carbon overmold is completely cut through and the carbon segments are electrically isolated from each other.
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Citations
18 Claims
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1. A carbon-segment commutator assembly for an electric motor, the commutator assembly comprising:
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an annular array of at least two circumferentially spaced conductor sections arranged around a rotational axis; an annular array of at least two circumferentially-spaced carbon segments formed of a conductive carbon composition, each carbon segment overmolded onto at least one surface of a corresponding one of the conductor sections forming an annular array of commutator sectors, the annular array of commutator sectors including an axial top end surface, an axial base end surface and an inner circumferential surface, the annular array of carbon segments defining a segmented composite outer-circumferential commutating surface of the commutator; and an overmolded insulator hub comprising a hub insulator material disposed on the axial top end, base end and inner circumferential surfaces of the annular array of commutator sectors to mechanically interlock the commutator sectors, the overmolded insulator hub including a central axial aperture disposed concentrically within the inner circumferential surface of the commutator sectors. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A carbon-segment commutator assembly for an electric motor, the commutator assembly comprising:
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an annular array of at least two circumferentially spaced metallic substrate sections arranged around a rotational axis; a cylindrical annular array of at least two circumferentially-spaced carbon segments formed of a conductive carbon composition, each segment connected to a corresponding one of the metallic substrate sections to form a commutator sector, a composite outer cylindrical surface of the annular carbon segment array defining a segmented cylindrical commutating surface; an insulator hub comprising a hub insulator material disposed within the annular carbon segment array and mechanically interlocking the carbon segments; and a first metallic layer plated onto a base end surface of each carbon segment, the metallic substrate sections soldered to the respective plated base end surfaces of the carbon segments to improve mechanical and electrical connections between the carbon segments and their respective substrate sections. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18)
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Specification