Rotating electric machine, electric wheel, and vehicle

Patent metadata

Field	Value
Publication number	US-12567779-B2
Application number	US-202118267286-A
Country	US
Kind code	B2
Filing date	Nov 25, 2021
Priority date	Dec 22, 2020
Publication date	Mar 3, 2026
Grant date	Mar 3, 2026

Abstract

The rotating electric machine includes a stator having a stator core around which a plurality of coils are wound; a rotor supported to be rotatable relative to the stator with a predetermined gap therebetween; a rotor case that holds the rotor; and a first bearing and a second bearing that rotatably support the rotor case. The rotating electric machine includes: a first flow path formation body that forms a first flow path through which a refrigerant flows to a coil end part protruding from the stator core; a first case part which forms an accommodation space of the first bearing, is connected to the first flow path of the first flow path formation body, and fills the accommodation space with the refrigerant.

First claim

The invention claimed is:

1 . A rotating electric machine which includes a stator having a plurality of coils and a stator core around which the plurality of coils are wound, a rotor rotatably supported relative to the stator with a predetermined gap therebetween, a rotor case that holds the rotor, and a first bearing and a second bearing that rotatably support the rotor case, the rotating electric machine comprising:
a first flow path formation body that forms a first flow path through which a refrigerant flows to a coil end part protruding from the stator core; a first case part that forms an accommodation space of the first bearing, that is connected to the first flow path of the first flow path formation body, and that fills the accommodation space with the refrigerant; a second flow path formation body that forms a second flow path through which the refrigerant flows to a coil end part arranged on a side opposite to the coil end part in an axial direction; and a second case part that forms an accommodation space of the second bearing, that is connected to the second flow path of the second flow path formation body, and that fills the accommodation space with the refrigerant, wherein, when viewed from a radial direction of the rotor, either or both of the first bearing and the second bearing are arranged on an outer diameter side of the coil end part and in a position overlapping the coil end part.

2 . The rotating electric machine according to claim 1 , wherein the refrigerant is a liquid.

3 . The rotating electric machine according to claim 1 , wherein the refrigerant is a lubricating oil for the first bearing and the second bearing.

4 . The rotating electric machine according to claim 1 , wherein operating temperature of the first bearing and the second bearing increases by heat generation of the coil, such that viscosity of the refrigerant in the first bearing and the second bearing is lowered.

5 . The rotating electric machine according to claim 1 , wherein, when viewed from an axial direction of a shaft supporting the rotor, either or both of the first bearing and the second bearing are arranged in a position overlapping the coil end part.

6 . The rotating electric machine according to claim 1 , wherein
the first case part forms a first space which communicates with the first flow path via the accommodation space of the first bearing, and the second case part forms a second space which communicates with the second flow path via the accommodation space of the second bearing.

7 . The rotating electric machine according to claim 6 , wherein
a pit that establishes communication between the first flow path and the first space is provided to the first flow path formation body or the first case part, and a pit that establishes communication between the second flow path and the second space is provided to the second flow path formation body or the second case part.

8 . An electric wheel including the rotating electric machine according to claim 1 , wherein the rotating electric machine is directly coupled to the wheel only by a mechanical coupling part, without interposing a gear.

9 . A vehicle including the rotating electric machine according to claim 1 , the vehicle comprising:
the rotating electric machine; a battery; and a power converter that converts DC power of the battery into AC power and supplies the AC power to the rotating electric machine, wherein the torque of the rotating electric machine is transmitted to vehicle wheels.

10 . The vehicle according to claim 9 , further comprising:
a controller that controls the power converter, wherein, by controlling the power converter to supply power from the battery to the coil in a state where the rotor is stopped, the controller performs warm-up operation control to increase temperatures of the first bearing and the second bearing by heat generation of the coil.

11 . A vehicle comprising a rotating electric machine, wherein the rotating electric machine includes a stator having a plurality of coils and a stator core around which the plurality of coils are wound, a rotor rotatably supported relative to the stator with a predetermined gap therebetween, a rotor case that holds the rotor, and a first bearing and a second bearing that rotatably support the rotor case, the rotating electric machine comprising:
a first flow path formation body that forms a first flow path through which a refrigerant flows to a coil end part protruding from the stator core; a first case part that forms an accommodation space of the first bearing, that is connected to the first flow path of the first flow path formation body, and that fills the accommodation space with the refrigerant; a second flow path formation body that forms a second flow path through which the refrigerant flows to a coil end part arranged on a side opposite to the coil end part in an axial direction; and a second case part that forms an accommodation space of the second bearing, that is connected to the second flow path of the second flow path formation body, and that fills the accommodation space with the refrigerant, the vehicle further comprising: a battery; a power converter that converts DC power of the battery into AC power and supplies the AC power to the rotating electric machine, wherein the torque of the rotating electric machine is transmitted to vehicle wheels; and a controller that controls the power converter, wherein, by controlling the power converter to supply power from the battery to the coil in a state where the rotor is stopped, the controller performs warm-up operation control to increase temperatures of the first bearing and the second bearing by heat generation of the coil.

12 . The vehicle according to claim 11 , wherein the refrigerant is a liquid.

13 . The vehicle according to claim 11 , wherein the refrigerant is a lubricating oil for the first bearing and the second bearing.

14 . The vehicle according to claim 11 , wherein operating temperature of the first bearing and the second bearing increases by heat generation of the coil, such that viscosity of the refrigerant in the first bearing and the second bearing is lowered.

15 . The vehicle according to claim 11 , wherein, when viewed from an axial direction of a shaft supporting the rotor, either or both of the first bearing and the second bearing are arranged in a position overlapping the coil end part.

16 . The vehicle according to claim 11 , wherein
the first case part forms a first space which communicates with the first flow path via the accommodation space of the first bearing, and the second case part forms a second space which communicates with the second flow path via the accommodation space of the second bearing.

17 . The vehicle according to claim 16 , wherein
a pit that establishes communication between the first flow path and the first space is provided to the first flow path formation body or the first case part, and a pit that establishes communication between the second flow path and the second space is provided to the second flow path formation body or the second case part.

18 . An electric wheel comprising the rotating electric machine according to claim 11 , wherein the rotating electric machine is directly coupled to the wheel only by a mechanical coupling part, without interposing a gear.

Assignees

• Hitachi Ltd

Inventors

• Takahashi Akeshi
• Suto Tetsuya
• Ito Makoto

Classifications

• H02K2209/00

  Specific aspects not provided for in the other groups of this subclass relating to systems for cooling or ventilating · CPC title

• H02K9/197

  in which the rotor or stator space is fluid-tight, e.g. to provide for different cooling media for rotor and stator · CPC title

• H02K5/165

  radially supporting the rotor around a fixed spindle; radially supporting the rotor directly (H02K5/167, H02K5/173 take precedence) · CPC title

• B60K7/0007

  the motor being electric · CPC title

• Y02T10/64

  Electric machine technologies in electromobility · CPC title