Electrical machine and vehicle equipped with the electrical machine

• US 10,680,478 B2
• Filed: 11/28/2018
• Issued: 06/09/2020
• Est. Priority Date: 08/17/2016
• Status: Active Grant

• Current Assignee: Bayerische Motoren Werke AG
• Original Assignee: Bayerische Motoren Werke AG
• Inventors: Huber, Andreas, El Khawly, Zakaria, Barti, Endre, Vichos, Anastasios
• Primary Examiner(s): Borroto, Alfonso Perez
• Assistant Examiner(s): Moraza, Alexander
• Application Number:
  US16/202,277
• Publication Number:
  US 20190097482A1
• Time in Patent Office: 559 Days
• Field of Search: 310 52, 310 54, 310 57- 64, 310216123
• CPC Class Codes: B60K 1/00 Arrangement or mounting of electrical propulsion units B60K7/00 takes precedence; arrangement or mounting of plural diverse prime-movers for mutual or common propulsion B60K6/00; electric transmission arrangements B60K17/12; electric equipment or propulsion of electrically-propelled vehicles per se B60L; current-collectors for power supply lines of electrically-propelled vehicles B60L5/00
• CPC Class Codes: B60K 11/02 with liquid cooling
• CPC Class Codes: B60K 2001/006 the electric motors
• CPC Class Codes: B60Y 2200/90 Vehicles comprising electric prime movers
• CPC Class Codes: H02K 1/32 with channels or ducts for flow of cooling medium
• CPC Class Codes: H02K 5/203 specially adapted for liquids, e.g. cooling jackets
• CPC Class Codes: H02K 7/003 Couplings; Details of shafts means for mounting rotors on shafts H02K1/28
• CPC Class Codes: H02K 9/00 Arrangements for cooling or ventilating channels or ducts in parts of the magnetic circuit H02K1/20, H02K1/32; channels or ducts in or between conductors H02K3/22, H02K3/24
• CPC Class Codes: H02K 9/19 for machines with closed casing and closed-circuit cooling using a liquid cooling medium, e.g. oil

Abstract

An electrical machine has a rotor with a hollow shaft which in its interior delimits a hollow shaft axial channel that extends in the axial direction and into which a cooling fluid can flow during operation of the electrical machine. A laminated rotor core is fitted radially to the outside of the hollow shaft and has two axial end sides. An axial channel which is delimited by the laminated rotor core extends in the axial direction from one of the two end sides of the laminated rotor core to the other of the two end sides of the laminated rotor core and is connected in a fluid-conducting manner to the hollow shaft axial channel, so that, during operation of the electrical machine, the cooling fluid can flow from the hollow shaft axial channel to the end sides via the axial channel and can flow radially to the outside downstream of the axial channel owing to centrifugal force.

Claims

1. An electrical machine, comprising:

a rotor which comprises

(i) a hollow shaft which, in an interior thereof, delimits a hollow shaft axial channel which extends n an axial direction and into which a cooling fluid flows during operation of the electrical machine;

(ii) a laminated rotor core which is fitted radially on an outside of the hollow shaft and has two axial end sides, and

(iii) an axial channel which is delimited by the laminated rotor core, extends in the axial direction from one of the two axial end sides of the laminated rotor core to the other of the two axial end sides of the laminated rotor core and is connected in a fluid-conducting manner to the hollow shaft axial channel, wherein

the rotor is configured such that, during operation of the electrical machine, the cooling fluid flows from the hollow shaft axial channel, via the axial channel, to the two axial end sides, and flows radially to the outside downstream of the axial channel owing to centrifugal force,

wherein the rotor has a radial channel via which the axial channel is connected in a fluid-conducting manner to the hollow shaft axial channel,

the laminated rotor core has at least one projection which protrudes from a radial inner surface of the laminated rotor core, and

the hollow shaft has at least one cutout in a radial outer surface of the hollow shaft, wherein the at least one projection engages the at least one cutout and the radial channel extends within the at least one projection.

2. The electrical machine as claimed in claim 1, further comprising:

a stator which is arranged radially outside the rotor, the stator having a laminated stator core which has two axial end sides, and a winding of electrical conductors, wherein

the axial end sides of the laminated stator core are arranged in alignment with the axial end sides of the laminated rotor core, and

the windings of the electrical conductors exit from the laminated stator core at the axial end sides to form end windings axially outside the laminated stator core, so that the cooling fluid which flows radially to the outside downstream of the axial channel impacts the end windings of the stator and cools said end windings.

3. The electrical machine as claimed in claim 1, wherein

the axial channel is arranged between the hollow shaft and the laminated rotor core and is delimited by the hollow shaft and the laminated rotor core.

4. The electrical machine as claimed in claim 3, wherein

the hollow shaft and/or the laminated rotor core have a cutout, which cutout forms the axial channel.

5. The electrical machine as claimed in claim 1, wherein

the axial channel is delimited by the laminated rotor core on the inside and on the outside in the radial direction.

6. The electrical machine as claimed in claim 1, wherein

the cooling fluid is electrically non-conductive.

7. The electrical machine as claimed in claim 6, wherein

the cooling fluid is an oil.

8. The electrical machine as claimed in claim 1, wherein

a plurality of axial channels is provided, which axial channels are arranged in a uniformly distributed manner in a circumferential direction.

9. The electrical machine as claimed in claim 1, further comprising:

a machine housing which houses the rotor and the stator.

10. The electrical machine as claimed in claim 9, wherein

the machine housing has a passage hole which is arranged at a lower end of the machine housing and via which the cooling fluid exits from the machine housing.

11. The electrical machine as claimed in claim 9, wherein

the machine housing has a housing cooling channel through which a further cooling fluid flows for cooling the machine housing.

12. The electrical machine as claimed in claim 11, wherein

the further cooling fluid is a mixture containing water and glycol.

13. The electrical machine as claimed in claim 7, wherein

the oil is a transmission oil.

14. The electrical machine as claimed in claim 1, wherein

the electrical machine is an electric motor for a vehicle.

15. A vehicle, comprising:

an electrical machine as claimed in claim 1; and

a conveying device configured to convey the cooling fluid that flows into the hollow shaft, wherein

the conveying device conveys a transmission oil of the vehicle as the cooling fluid.