# US 10,873,225 B2 · Rotor for rotary electric machine having a gap for alleviating stress during rotation

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- Number: US 10,873,225 B2
- Document ID: US10873225B2
- Status: Granted
- Kind: B2
- Application number: 16/236,822
- Filed: 2018-12-31
- Published: 2019-07-11
- Granted: 2020-12-22
- Earliest claimed: 2018-01-11
- Assignees: Honda Motor Co., Ltd.
- Applicants: Honda Motor Co., Ltd.
- Inventors: Kentaro Fukui; Masashi Inoue
- Web page: https://patentgrep.com/patent/US10873225B2

## CPC

- H02K 1/276: Magnets embedded in the magnetic core, e.g. interior permanent magnets [IPM]
- H02K 2213/03: Machines characterised by numerical values, ranges, mathematical expressions or similar information
- H02K: DYNAMO-ELECTRIC MACHINES (dynamo-electric relays H01H53/00; conversion of DC or AC input power into surge output power {H03K3/53})

## Abstract

A rotor for a rotary electric machine includes: a rotor core which includes a magnet insertion hole; and a permanent magnet housed in the magnet insertion hole. The permanent magnet has an arc shape which is convex toward an axial line. The rotor core includes: an outer-circumference core part; an inner-circumference core part; and connection ribs which connect the outer-circumference core part and the inner-circumference core part. The permanent magnet is supported in the rotor core in such a manner that circumferential ends abut on an inner surface of the magnet insertion hole. A circumferential center portion of the permanent magnet is separated from an outer-circumference-side inner surface of the magnet insertion hole. In the circumferential center portion of the permanent magnet, a gap is provided between an outer-circumference-side outer surface of the permanent magnet and the outer-circumference-side inner surface of the magnet insertion hole.

## Claims

### Claim 1

A rotor for a rotary electric machine, comprising:
a rotor core which rotates around an axial line and includes a magnet insertion hole extending in parallel to the axial line; and
a permanent magnet which is housed in the magnet insertion hole, wherein
the permanent magnet has an arc shape which is convex toward the axial line when viewed from a direction of the axial line,
the rotor core includes:
an outer-circumference core part which is positioned on an outer-circumference-side of the magnet insertion hole;
an inner-circumference core part which is positioned on an inner-circumference-side of the magnet insertion hole; and
connection ribs which are positioned in both circumferential ends of the magnet insertion hole and connect the outer-circumference core part and the inner-circumference core part,
the permanent magnet is supported in the rotor core in such a manner that circumferential ends which are positioned on both circumferential sides of the permanent magnet abut on an inner surface of the magnet insertion hole,
a circumferential center portion of the permanent magnet is separated from an outer-circumference-side inner surface of the magnet insertion hole,
in the circumferential center portion of the permanent magnet, a gap is provided between an outer-circumference-side outer surface of the permanent magnet and the outer-circumference-side inner surface of the magnet insertion hole, and
a whole of circumferential end side lateral surfaces of the permanent magnet do not abut on circumferential lateral inner surfaces of the magnet insertion hole.

### Claim 2 (depends on 1)

The rotor for the rotary electric machine according to claim 1, wherein
the circumferential ends of the permanent magnet are circumferential ends of the outer-circumference-side outer surface of the permanent magnet which faces the outer-circumference-side inner surface of the magnet insertion hole, and
a convex part which abuts on the circumferential ends of the permanent magnet is provided in the outer-circumference-side inner surface of the magnet insertion hole.

### Claim 3 (depends on 1)

The rotor for the rotary electric machine according to claim 1, wherein
the circumferential ends of the permanent magnet are circumferential ends of the outer-circumference-side outer surface of the permanent magnet which face the outer-circumference-side inner surface of the magnet insertion hole,
the outer-circumference-side inner surface of the magnet insertion hole has an arc shape which is convex toward the axial line, and
a circular arc radius of the outer-circumference-side inner surface of the magnet insertion hole is larger than a circular arc radius of the outer-circumference-side outer surface of the permanent magnet.