Permanent magnet type motor and method of producing permanent magnet type motor

• US 6,717,315 B1
• Filed: 07/24/2001
• Issued: 04/06/2004
• Est. Priority Date: 12/13/1999
• Status: Expired due to Term

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Katou, Masaki, Kazama, Osamu, Oikawa, Tomoaki, Baba, Kazuhiko, Masumoto, Koji, Tajima, Tsuneyoshi
• Primary Examiner(s): Le, Dang
• Assistant Examiner(s): ADDISON, KAREN B
• Application Number:
  US09/869,322
• Time in Patent Office: 987 Days
• Field of Search: H02/K 2.112, 310/156, 310/216, 310/261, 310/262, 310/218, 310/214, 310/314, 310/186
• US Class Current: 310/156.45
• CPC Class Codes: H02K 1/276 Magnets embedded in the magnetic core, e.g. interior permanent magnets [IPM]
• CPC Class Codes: H02K 1/278 Surface mounted magnets; Inset magnets
• CPC Class Codes: H02K 29/03 with a magnetic circuit specially adapted for avoiding torque ripples or self-starting problems

Abstract

To provide a permanent-magnet motor having a permanent magnet which can reduce the vibration and the noise without lowering the efficiency of the motor, the permanent-magnet motor according to, the present invention has a stator 1 having stator winding of plural phases, a rotor 10 having a stator core 12 facing to inside of the stator across a gap part and a permanent magnet 14 provided to the rotor core. In the permanent-magnet motor, the permanent magnet 14 is made to have both a convex part to the inner diameter side and a convex part to the outer diameter side in the cross section taken vertically to the rotation axis, and a focus of magnetic orientation of each magnetic pole of the permanent magnet is located outside of the rotor 10.

Claims

1. A permanent-magnet motor comprising:

a stator having stator winding of plural phases; and

a rotor facing to inside of the stator across a gap part, and having a rotor core and a permanent magnet provided to the rotor core,

wherein the permanent-magnet is made so as to have both of a convex part to an inner diameter side and a convex part lo an outer diameter side in a cross section taken vertically to an axis;

wherein a focus of magnetic orientation of each magnetic pole of the permanent magnet is located outside of the rotor,

wherein the rotor is formed by a rotor core assembly made by multilayering multiple pieces of core laminations, each having plural containing holes for inserting the permanent magnets and the permanent magnets are inserted into the containing holes for inserting the permanent magnets; and

wherein a thickness of the rotor core, which separates the permanent magnet and the gap, is made within ±

30% of a thickness of the rotor core lamination.

2. The permanent-magnet motor of claim 1, wherein the rotor is formed by including the permanent magnets in an outer peripheral part of the rotor core and a non-magnetic protect pipe is attached around the permanent magnets.

3. The permanent-magnet motor of claim 1,

wherein when a radius of an arc of an outer diameter side of the containing hole is R, and a radius of an arc of an outer diameter side of the permanent magnet inserted into the containing hole is r, it is set as R< r.

4. The permanent-magnet motor of claim 1, wherein the stator is a concentrated winding stator made by directly winding a coil around a teeth part of the stator.

5. The permanent-magnet motor of claim 1, wherein a radius of the convex part to the inner diameter side of the permanent magnet is smaller than a radius of the convex part to the outer diameter side of the permanent magnet.

6. The permanent-magnet motor of claim 1, wherein a straight line part is provided to each of a part of an arc of an inner diameter side of the containing hole for inserting the permanent magnet and a part of an arc of an inner diameter side of the permanent magnet.

7. A permanent-magnet motor comprising:

a stator having stator winding of plural phases; and

a rotor facing to inside of the stator across a gap part, and having a rotor core and a permanent magnet provided to the rotor core,

wherein the permanent magnet is made so as to have both of a convex part to an inner diameter side and a convex part to an outer diameter side in a cross section taken vertically to an axis,

wherein the rotor is formed by a rotor core assembly made by multilayering multiple pieces of core laminations, each having plural containing holes for inserting the permanent magnets and the permanent magnets are inserted into the containing holes for inserting the permanent magnets; and

wherein a thickness of the rotor core, which separates the permanent magnet and the gap, is made within ±

30% of a thickness of the rotor core lamination.

8. A method for manufacturing a permanent-magnet motor including a stator having stator winding of plural phases and a rotor facing to inside of the stator across a gap part, and having a rotor core and a permanent magnet provided to the rotor core, the method comprising:

making the permanent magnet so as to have both a convex part to an inner diameter side and a convex part to an outer diameter side in a cross section taken vertically to an axis

forming a rotor core assembly by multilayering multiple rotor core laminations, each having plural containing holes for inserting the permanent magnets; and

inserting the permanent magnets into the plural containing holes for inserting the permanent magnets,

wherein a thickness of the rotor core, which separates the permanent magnet and the gap part, is made within ±

30% of a thickness of the multiple rotor core laminations.