Rotor core, rotor, and rotating electrical machine

1 . A rotor core having plural holes including holes in which permanent magnets are installed, the rotor core comprising:

a high permeability portion; and

a low permeability portion having a relative permeability that is smaller than a relative permeability of the high permeability portion and that is greater than a relative permeability of a vacuum,

wherein only a part of a first outer peripheral bridge portion, which is disposed at a region configuring one pole of the rotor core and at a leading side in a rotational direction relative to a circumferential direction center of the region, and at least part of a region of which is disposed at an outer peripheral surface side of the rotor core relative to at least one of regions where the permanent magnets are installed, is the low permeability portion, and

an entirety of a second outer peripheral bridge portion, which is disposed at a region configuring one pole of the rotor core and at a trailing side in a rotational direction relative to a circumferential direction center of the region, and at least part of a region of which is disposed at the outer peripheral surface side of the rotor core relative to at least one of regions where the permanent magnets are installed, is the low permeability portion.

2 . The rotor core of claim 1 , wherein the low permeability portion and the high permeability portion are integrally formed of the same material.

3 . The rotor core of claim 2 , wherein:

the high permeability portion is a portion configured by a soft magnetic material, and

the low permeability portion is a portion in which a permeability of the soft magnetic material has been lowered.

4 . The rotor core of claim 1 , wherein the first outer peripheral bridge portion is disposed at at least one of between the holes and the outer peripheral surface or between two of the holes including the holes at least parts of which are disposed at the outer peripheral surface side relative to at least one region of the regions where the permanent magnets are installed.

5 . A rotor comprising:

the rotor core of claim 1 ; and

the permanent magnets.

6 . The rotor core of claim 1 , wherein an entirety of an inner peripheral bridge portion, at least part of a region of which is disposed at an inner peripheral surface side of the rotor core relative to at least one of regions where the permanent magnets are installed, is the low permeability portion.

7 . The rotor core of claim 6 , wherein:

the rotor core has two or more inner peripheral bridge portions per pole, and

entireties of the two or more inner peripheral bridge portions are low permeability portions.

8 . The rotor core of claim 6 , wherein the inner peripheral bridge portion is located between two of the holes in which the permanent magnets are installed.

9 . The rotor core of claim 6 , wherein:

the plural holes further include holes in which permanent magnets are not installed, and

the inner peripheral bridge portion is located at at least one of between a hole in which a permanent magnet is installed and a hole in which a permanent magnet is not installed or between two holes in which permanent magnets are not installed.

10 . The rotor core of claim 6 , wherein there is at least one inner peripheral bridge portion between end portions, on the inner peripheral surface side, of two holes disposed so that magnetic pole faces of the permanent magnets installed therein are inclined relative to an outer peripheral surface of the rotor core, among the holes in which the permanent magnets are installed.