Motor

Patent metadata

Field	Value
Publication number	US-12149125-B2
Application number	US-202017908601-A
Country	US
Kind code	B2
Filing date	Sep 14, 2020
Priority date	Mar 18, 2020
Publication date	Nov 19, 2024
Grant date	Nov 19, 2024

Abstract

A motor includes a cylindrical rotor core, and a magnet group including first magnets and second magnets alternately arranged along a circumferential direction of the rotor core. A first magnetic flux line generated in the first magnets extends along a radial direction of the rotor core, and a second magnetic flux line generated in the second magnets is inclined with respect to the first magnetic flux line. The rotor core includes an inner portion located on a radially inner side of the magnet group and an outer portion located on a radially outer side of the magnet group. The outer portion includes a first iron core that covers the first magnet from the radially outer side, and a second iron core that covers at least a portion of the second magnet in the central axis direction of the rotor core from the radially outer side.

First claim

The invention claimed is:

1. A motor comprising:
a rotor core having a cylindrical shape; and
a magnet group including a first magnet and a second magnet alternately arranged along a circumferential direction of the rotor core; wherein
a first magnetic flux line generated by the first magnet extends along a radial direction of the rotor core;
a second magnetic flux line generated by the second magnet is inclined with respect to the first magnetic flux line;
the rotor core includes an inner portion located on an inner side of the magnet group in a radial direction, and an outer portion located on an outer side of the magnet group in the radial direction;
the outer portion includes a first iron core that covers the first magnet from an outside in the radial direction, and a second iron core that covers at least a portion of the second magnet in a central axis direction of the rotor core from the outside in the radial direction; and
a plurality of the second iron cores are spaced apart at a distance from each other in the central axis direction.

2. The motor according to claim 1 , wherein a total thickness of the second magnet along the radial direction is thicker than a total thickness of the first magnet along the radial direction.

3. The motor according to claim 2 , wherein a total thickness of the second iron core along the radial direction is thinner than a total thickness of the first iron core along the radial direction.

4. The motor according to claim 1 , wherein at least a portion of the second iron core is made of a magnetic material.

5. The motor according to claim 1 , wherein the rotor core includes a connecting portion that connects the inner portion and the outer portion.

6. The motor according to claim 1 , wherein
a plurality of the first magnets is provided; and
the first magnetic flux line of one of the first magnets adjacent to each other in the circumferential direction via the second magnet is directed to an inside of the rotor core, and the first magnetic flux line of another one of the first magnets is directed to an outside of the rotor core.

7. The motor according to claim 1 , wherein the second magnet is divided into two second magnets so that directions of the second magnetic flux lines are different.

8. The motor according to claim 7 , wherein one of the second magnetic flux lines of the two divided second magnets is directed to an inside of the rotor core, and another one of the second magnetic flux lines is directed to an outside of the rotor core.

Assignees

• Nidec Corp

Inventors

• Ueda Tomoya

Classifications

• H02K1/2766 Primary

  having a flux concentration effect · CPC title

• H02K1/2783 Primary

  with magnets arranged in Halbach arrays · CPC title