A pump is driven by a compact electric motor in which a coil is disposed in a ring form around and along a stator core which has a plurality of claw magnetic poles that extend alternately from both ends of one member of the stator core toward the end of the other member thereof. A stator core can be made from a compressed powder core by molding with resin, with the molded portion able to serve as a partition separating pump and motor units.
1. An electric pump for discharging a liquid, the electric pump comprising:
an electric motor, said electric motor including
a coil wound in a ring form,
a stator core formed along said coil in a tubular form so that different magnetic poles are formed alternately in the circumferential direction as said coil is energized, said core having a molded portion, formed by molding a non-magnetic material, at least on the inner periphery thereof, and
a rotor disposed to be opposed to said magnetic pole forming portions of said stator core so that different magnetic poles are formed in the circumferential direction, said rotor rotating in a liquid; and
a pump structural body adapted to discharge a liquid as a rotational force is given to said pump structural body by said rotor;
wherein said non-magnetic material and said magnetic pole are formed alternately on the inner peripheral surface of said stator core; and
wherein said stator core and said rotor are housed in a motor housing, and a rotation stop mechanism is provided between the side end portion of said pump structural body disposed along the inner periphery of said motor housing and said stator core to restrict the relative rotation of said stator core.
2. The electric pump of claim 1 , wherein one axial end of said motor housing serves also as a pump housing adapted to house said pump structural body.
3. The electric pump of claim 1 , wherein the side end portion of said pump structural body disposed along the inner periphery of said motor housing is in close contact with said stator core.
4. The electric pump of claim 1 , wherein said rotation stop mechanism comprises a projected portion on one side and a recessed portion on the other side.
5. The electric pump of claim 1 , wherein said stator core is formed to include a plurality of phases, and wherein said rotation stop mechanism is provided on said stator core for each phase.
6. An electric pump for discharging a liquid, the electric pump comprising:
an electric motor, said electric motor including
a coil wound in a ring form,
a stator core formed along said coil in a tubular form so that different magnetic poles are formed alternately in the circumferential direction as said coil is energized, said core having a molded portion, formed by molding a non-magnetic material, at least on the inner periphery thereof, and
a rotor disposed to be opposed to said magnetic pole forming portions of said stator core so that different magnetic poles are formed in the circumferential direction, said rotor rotating in a liquid; and
a pump structural body adapted to discharge a liquid as a rotational force is given to said pump structural body by said rotor;
wherein said non-magnetic material and said magnetic pole are formed alternately on the inner peripheral surface of said stator core; and
wherein bearings for said rotor are disposed along the inner periphery of said rotor.