Motor and motor rotor having embedded permanent magnets

• US 6,225,724 B1
• Filed: 07/21/1999
• Issued: 05/01/2001
• Est. Priority Date: 10/23/1998
• Status: Expired due to Fees

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Ohshige, Toyomi, Toide, Yukari, Daikoku, Akihiro, Nakahara, Yuji, Ugai, Yoshikazu
• Primary Examiner(s): NGUYEN, TRAN N
• Application Number:
  US09/357,950
• Time in Patent Office: 650 Days
• Field of Search: 310/156, 310/216, 310/91, 310/254, 310/261, 310/43, 29/596-598
• US Class Current: 310/156.53
• CPC Class Codes: H02K 1/276 Magnets embedded in the magnetic core, e.g. interior permanent magnets [IPM]
• CPC Class Codes: H02K 1/2766 having a flux concentration effect
• CPC Class Codes: H02K 15/03 having permanent magnets
• CPC Class Codes: H02K 2201/06 Magnetic cores, or permanent magnets characterised by their skew

Abstract

A motor embedded with magnets having good properties and productivity. A rotor of this motor includes a rotor core with laminated rotor core plates punched out of an electromagnetic steel plate and studded with bonded magnets of a powdered permanent magnet material and a resin in groups of slits located in the rotor core for each pole of the rotor.

Claims

1. A motor having embedded permanent magnets comprising a rotor including

a plurality of laminated core blocks, each core block having two surfaces perpendicular to an axial direction of the motor and containing a plurality of rotor core plates, the rotor core plates being made from a magnetic material, each of the plurality of core blocks including independent embedded permanent magnets, and

spacers respectively comprising a thin layer of the permanent magnets on both of the two surfaces of the plurality of core blocks, the spacers having mutually complementary shaped recesses and projections, the core blocks being laminated so that the recesses and the projections of the spacers in adjoining core blocks are engaged, each of the rotor core plates having a plurality of slits with embedded permanent magnets in the slits, the permanent magnets comprising a powered permanent magnet material dispersed in a resin and located in a group of slits for each pole of said rotor.

2. A rotor for an electric motor comprising:

a plurality of substantially identical sheets of magnetic material, each sheet including groups of slits, each group including a plurality of slits for forming a respective pole of the rotor, the plurality of sheets being laminated and axially aligned and the slits within each of the sheets being substantially aligned with the slits in an adjacent sheet;

a polymer matrix in which a powder of a permanent magnet material is dispersed, filling the slits in each of the sheets of the magnetic material; and

a plurality of non-magnetic pins, each of the pins extending through the laminated sheets at a mid-point of a respective slit.

3. A rotor for an electric motor comprising:

a plurality of substantially identical sheets of magnetic material, each sheet including groups of slits, each group including a plurality of slits for forming a respective pole of the rotor, the plurality of sheets being laminated and axially aligned and the slits within each of the sheets being substantially aligned with the slits in an adjacent sheet;

a polymer matrix in which a powder of a permanent magnet material is dispersed, filling the slits in each of the sheets of the magnetic material; and

a plurality of non-magnetic voids, each of the voids extending through the laminated sheets at a mid-point of a respective slit.

4. A rotor for an electric motor comprising:

a plurality of substantially identical sheets of magnetic material, each sheet including groups of slits, each group including a plurality of slits for forming a respective pole of the rotor, the plurality of sheets being laminated and axially aligned and each of the sheets being rotationally offset, about an axial direction, relative to an adjacent sheet and

a polymer matrix in which a powder of a permanent magnet material is dispersed, filling the slits in each of the sheets of the magnetic material.

5. A rotor for an electric motor comprising:

a plurality of substantially identical sheets of magnetic material, each sheet including groups of slits, each group including a plurality of slits for forming a respective pole of the rotor, the plurality of sheets being laminated and axially aligned and wherein the plurality of sheets are divided into groups, each group including an identical number of sheets, the sheets within each group of sheets being axially aligned, each group of sheets being rotationally offset, about an axial direction, with respect an adjacent group of sheets; and

a polymer matrix in which a powder of a permanent magnet material is dispersed, filling the slits in each of the sheets of the magnetic material.