# US 2019/0173366 A1 · Stator core and motor

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- Number: US 2019/0173366 A1
- Document ID: US20190173366A1
- Status: Published application
- Kind: A1
- Application number: 16/321,516
- Filed: 2017-08-04
- Published: 2019-06-06
- Earliest claimed: 2016-08-05
- Assignees: Nidec Corporation
- Applicants: Nidec Corporation
- Inventors: Tomoya UEDA; Yusuke MAKINO
- Web page: https://patentgrep.com/patent/US20190173366A1

## CPC

- H02K 21/22: with magnets rotating around the armatures, e.g. flywheel magnetos
- H02K 1/14: Stator cores with salient poles
- H02K 1/146: {consisting of a generally annular yoke with salient poles}
- H02K 1/165: {Shape, form or location of the slots}
- H02K 1/278: Surface mounted magnets; Inset magnets
- H02K 1/2791: Surface mounted magnets; Inset magnets
- H02K 7/14: Structural association with mechanical loads, e.g. with hand-held machine tools or fans (with fan or impeller for cooling the machine H02K9/06)
- H02K 21/16: having annular armature cores with salient poles (with homopolar co-operation H02K21/20)
- H02K 21/227: {having an annular armature coil}
- H02K 29/03: with a magnetic circuit specially adapted for avoiding torque ripples or self-starting problems
- 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 stator core includes an annular core back and teeth extending radially from the core back to a rotor magnet includinq magnets. A ratio of a number of slots, which is equal to a number of the teeth, to a number of poles, which is equal to a number of magnets of the rotor magnet, is 3:4. A slot open ratio, which is a ratio of a slot open angle between two adjacent teeth in a peripheral direction to an angle between center lines of the two teeth is 0.5 or more. When a ratio of a peripheral angle of one magnet to an angle between center positions of two adjacent magnets in the peripheral direction is a magnet ratio, a ratio of the slot open ratio to the magnet ratio is 0.6 to 0.7.

## Claims

### Claim at position 1

1-4. (canceled)

### Claim 5

A stator core comprising:
an annular core back; and
a plurality of teeth extending radially from the core back to a rotor magnet including a plurality of magnets; wherein
a ratio of a number of slots, which is equal to a number of the plurality of teeth, to a number of poles, which is equal to a number of the plurality of magnets of the rotor magnet, is 3:4;
a slot open ratio, which is a ratio of a slot open angle between two adjacent teeth in a peripheral direction to an angle between center lines of the two teeth, is 0.5 or more; and
when, in the rotor magnet, a ratio of a peripheral angle of one magnet to an angle between center positions of two adjacent magnets in the peripheral direction is a magnet ratio, a ratio of the slot open ratio to the magnet ratio is 0.6 to 0.7.

### Claim 6 (depends on 5)

The stator core according to claim 5, wherein the magnet width ratio is 0.75 to 0.90.

### Claim 7 (depends on 5)

A motor comprising:
an armature including the stator core according to claim 5;
a rotor including the rotor magnet; and
a bearing rotatably supporting the rotor; wherein
the rotor magnet is disposed radially outward of the plurality of teeth; and
the number of slots is 12, 18 or 24.

### Claim 8 (depends on 5)

A motor comprising:
an armature including the stator core according to claim 5;
a rotor including the rotor magnet; and
a bearing rotatably supporting the rotor; wherein
the rotor magnet is disposed radially inward of the plurality of teeth; and
the number of slots is 18.