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Rotor for electric motor and method of making the same
| Details |
Inventors: Shiga, Tsuyoshi; Endou, Masami;
Assignee: Kabushiki Kaisha Toshiba (Tokyo, JP)
Primary Examiner: Ramirez; Nestor
Assistant Examiner: Hanh; Nguyen
Attorney, Agent or Firm: Pillsbury Winthrop LLP
A rotor for an electric motor includes a frame previously formed and fixed to a rotational shaft of the motor so as to be rotated with the rotational shaft, and a magnet molded from a molten magnetic resin so as to be disposed at a stator side of the frame and so as to be integrated with the frame. |
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DETAILED DESCRIPTION Therefore, an object of the present invention is to provide a rotor for the electric motor whose size, weight and cost can be reduced, which can improve the manufacturing efficiency and can readily be disassembled when disposed of and in which the accuracy in the final positions of the magnets can be improved, and a method of making the rotor.
The present invention provides a rotor for an electric motor including a rotational shaft and a stator having a stator core, comprising a frame previously formed and fixed to the rotational shaft of the motor so as to be rotated with the rotational shaft, and a magnet molded from a molten magnetic resin so as to be disposed at a stator core side of the frame and so as to be integrated with the frame.
According to the above-described rotor, the magnets are made from the magnetic resin so as to be disposed at the stator core side of the frame.
Accordingly, since the frame and magnets can be integrated with each other, the resin need not be provided only to integrate the frame and the magnets.
Furthermore, components for the magnets need not be disposed at the stator core side of the frame one by one, and the final positions of the magnets are not affected by the result of molding from the resin.
Additionally, the resin need not be disposed over the outer and inner circumferential faces of the frame.
In a preferred form, the magnet is anisotropic with respect to poles thereof.
Consequently, the magnet can be formed so that the magnetic pole possesses a large magnetic force.
In another preferred form, the frame has an axially elongated hole or a plurality of axially aligned holes at a position between magnetic poles of the magnet with respect to the rotational shaft.
Consequently, magnetic flux is prevented from leaking through the frame by the elongated hole or axially aligned holes when the magnet is rendered anisotropic.
Further, since the magnetic resin fills the elongated hole or axially aligned holes, the strength of the magnet relative to the frame can be improved
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Generators or Motors 
