Rotor for rotary electric machine

• US 20050121990A1
• Filed: 12/02/2004
• Published: 06/09/2005
• Est. Priority Date: 12/08/2003
• Status: Active Grant

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Kaneko, Yutaro
• Granted Patent: US 7,327,062 B2
• Time in Patent Office: Days
• US Class Current: 310/156.470
• CPC Class Codes: H02K 1/276 Magnets embedded in the magnetic core, e.g. interior permanent magnets [IPM]
• CPC Class Codes: H02K 29/03 with a magnetic circuit specially adapted for avoiding torque ripples or self-starting problems

Abstract

A rotor (10) for a rotary electric machine (1) comprises a rotation shaft (11), and a plurality of rotor cores (120-129) fixed to the rotation shaft (11) and axially split. The rotor cores (120-129) have outer peripheral surfaces (120A-129A) with a circular cross section. Permanent magnets (13) extending through the rotor cores (120-129) are arranged at equal circumferential intervals. Voids (120B-129B) extending axially through the rotor cores (120-129) are formed between the outer peripheral surfaces (120A-129A) and the permanent magnets (13). The voids (120B-129B) of two adjacent rotor cores (120-129) are formed at circumferentially different positions, thereby being capable of suppressing the cogging torque without introducing a reduction in output torque.

Claims

1. A rotor for a rotary electric machine, comprising:

a rotation shaft;

a plurality of rotor cores fixed to the rotation shaft and axially split, each of the rotor cores having outer peripheral surfaces with a circular cross section; and

permanent magnets arranged at equal circumferential intervals and extending through the rotor cores;

wherein voids which axially penetrate the rotor cores are formed between the outer peripheral surfaces of the rotor cores and the permanent magnets, and the voids of two adjacent rotor cores are formed at circumferentially different positions.

2. The rotor as defined in claim 1,

wherein the voids comprise axial grooves formed at equal angular intervals in the outer peripheral surfaces.

3. The rotor as defined in claim 1,

wherein the voids comprise through holes axially extending through the rotor cores.

4. The rotor as defined in claim 1,

wherein the rotor further comprises non-magnetic resin materials filling the voids.

5. The rotor as defined in claim 1,

wherein two adjacent rotor cores are of the same specifications with respect to the permanent magnets and the voids and are arranged in axially opposite directions.

6. The rotor as defined in claim 1,

wherein the voids of the rotor cores are arranged at equal angular intervals as seen from an axial direction.

7. The rotor as defined in claim 1,

wherein the voids of the rotor cores are formed at two or more positions per permanent magnet.

8. The rotor as defined in claim 1,

wherein the rotor comprises a first rotor core, a second rotor core, a third rotor core, and a fourth rotor core arranged axially in that order,

wherein the first rotor core and the fourth rotor core are of the same specifications with respect to the permanent magnets and the voids and are arranged axially in opposite directions, and

wherein the second rotor core and the third rotor core are of the same specifications with respect to the permanent magnets and the voids and are arranged axially in opposite directions.