ELECTRICAL MACHINE, IN PARTICULAR FOR A VEHICLE

• US 20200136445A1
• Filed: 12/27/2019
• Published: 04/30/2020
• Est. Priority Date: 06/27/2017
• Status: Active Grant

• Current Assignee: Mahle International GmbH (MAHLE-STIFTUNG GmbH)
• Original Assignee: Mahle International GmbH (MAHLE-STIFTUNG GmbH)
• Inventors: Hoerz, Mirko, Steurer, Hans-Ulrich, Sonntag, Josef, Markic, Stojan, Licen, Andrej, Medvescek, Aleks, Sever, Peter, Grabherr, Philip
• Granted Patent: US 11,190,064 B2
• Time in Patent Office: Days
• CPC Class Codes: H02K 1/20 with channels or ducts for flow of cooling medium
• CPC Class Codes: H02K 3/24 with channels or ducts for cooling medium between the conductors
• CPC Class Codes: H02K 3/30 Windings characterised by the insulating material
• CPC Class Codes: H02K 3/48 in slots
• CPC Class Codes: H02K 5/08 Insulating casings
• CPC Class Codes: H02K 5/15 Mounting arrangements for bearing-shields or end plates
• CPC Class Codes: H02K 9/227 Heat sinks

Abstract

An electrical machine for a vehicle includes a rotor, which can be rotated about an axis of rotation, by which an axial direction of the electrical machine is defined, a stator with stator windings; and a cooling channel, or a plurality of cooling channels, through which a coolant flows. The stator has stator teeth, which extend along the axial direction and are spaced apart from each other along a circumferential direction and which bear the stator windings. At least one stator winding is embedded in an electrically insulating plastic for thermal coupling, the electrically insulating plastic is arranged, together with the at least one stator winding, in an intermediate space, which is formed between two stator teeth adjacent in the circumferential direction, and the electrically insulating plastic is formed by a first plastic mass of a first plastic material and a second plastic mass of a second plastic material.

Claims

1. An electrical machine, in particular for a vehicle, the electrical machine comprising:

a rotor, which can be rotated about an axis of rotation, which defines an axial direction of the electrical machine;

a stator, which has stator windings;

at least one cooling duct, through which a coolant can flow;

a coolant distributor chamber for cooling the stator windings; and

a coolant collector chamber arranged at an axial distance to said coolant distributor chamber,

wherein the coolant distributor chamber communicates fluidically with the coolant collector chamber by the at least one cooling duct, through which the coolant can flow,

wherein the stator has stator teeth, which extend along the axial direction, which are arranged spaced apart from one another along a circumferential direction, and which support the stator windings,

wherein least one stator winding is embedded into an electrically insulating plastic for the thermal coupling,

wherein the electrically insulating plastic is arranged with at least one stator winding in at least one space, which is embodied between two stator teeth, which are adjacent in the circumferential direction,

wherein the electrically insulating plastic is formed by a first plastic compound of a first plastic material, and by a second plastic compound of a second plastic material,

wherein the first or/and second plastic compound at least partially surrounds at least one winding section of a stator winding, which protrudes axially from a space, and thereby partially limits the coolant distributor chamber and/or the coolant collector chamber, so that this winding section is electrically insulated with respect to the coolant during operation of the electrical machine,

wherein the at least one stator winding is embedded into the first plastic compound of the first plastic material in the at least one space,

wherein the first plastic compound, with the stator winding embedded therein, is at least partially surrounded by the second plastic compound of the second plastic material,

wherein surface sections of the stator, which limit the space, are at least partially coated with the second plastic compound,

wherein the stator is arranged axially between a first and a second bearing shield,

wherein a portion of the coolant distributor chamber is arranged in a first bearing shield and the portion of the coolant collector chamber in the second bearing shield,

wherein the coolant distributor chamber and the coolant collector chamber are each partially formed by a first hollow space and a second hollow space, which is provided in the first plastic compound,

wherein the first hollow space is supplemented with a hollow space embodied in the first bearing shield to form the coolant distributor chamber, and the second hollow space is supplemented with the hollow space embodied in the second bearing shield to form the coolant collector chamber,

wherein, in a longitudinal section along the axis of rotation, the coolant distributor chamber and the coolant collector chamber surround a first or second axial end section, respectively, of the respective stator winding in a U-shaped manner, thus axially on the end side as well as radially on the inside and radially on the outside,

wherein the at least one cooling duct is arranged radially inside and at least one further cooling duct is arranged radially outside of the respective stator winding in the space,

wherein at least one radially inner cooling duct is embodied as tube body, which surrounds a tube body internal space,

wherein at least one separating element, which divides the tube body internal space into at least two partial cooling ducts, which are fluidically separated from one another, is molded on the tube body, and

wherein, in a cross-section perpendicular to the axis of rotation, the tube body forming a radially inner cooling duct is injection molded completely with the first plastic compound, and a radially outer cooling duct is injection molded completely with the second plastic compound.

2. The electrical machine according to claim 1, wherein:

a thermal conductivity of the first plastic material is larger than the thermal conductivity of the second plastic material, or

the thermal conductivity of the first plastic material is smaller than the thermal conductivity of the second plastic material, or

the thermal conductivity of the first plastic material is identical to the thermal conductivity of the second plastic material.

3. The electrical machine according to claim 1, wherein the coolant distributor chamber and/or the coolant collector chamber is exclusively arranged in an axial extension of the stator adjacent to the latter and does not protrude therefrom along a radial direction or the stator, respectively.

4. The electrical machine according to claim 1, wherein the first plastic component and the second plastic compound are arranged in at least two spaces, or in all spaces.

5. The electrical machine according to claim 1, wherein:

the first plastic material includes a thermoset or a thermoplastic or is the thermoset or the thermoplastic, and/or

the second plastic material includes the thermoplastic or the thermoset or is the thermoplastic or the thermoset.

6. The electrical machine according to claim 1, wherein the at least one cooling duct is arranged in the electrically insulating plastic.

7. The electrical machine according to claim 1, wherein the at least one cooling duct is formed by at least one, or by a plurality of aperture/apertures, which is/are provided in the electrically insulating plastic, or in the second plastic compound, and through which the coolant can flow.

8. The electrical machine according to claim 7, wherein the second plastic compound at least partially, or completely surrounds or encases at the least one aperture, or in each case all apertures, in the cross-section perpendicular to the axial direction.

9. The electrical machine according to claim 7, wherein the at least one aperture has a geometry of a rectangle including two broad sides and two narrow sides in the cross-section perpendicular to the axial direction.

10. The electrical machine according to claim 1, wherein the at least one cooling duct is at least partially, or completely surrounded or encased by the electrically insulating plastic, or by the second plastic compound.

11. The electrical machine according to claim 1, wherein the coolant distributor chamber and/or the coolant collector chamber are at least partially arranged in the electrically insulating plastic, or in the first plastic compound, for thermally coupling to the stator windings.

12. The electrical machine according to claim 1, wherein the coating of the second plastic compound encloses the respective stator winding inside the space over at least an entire length of the respective space, measured along the axial direction, in the U-shaped manner in the circumferential direction.

13. The electrical machine according to claim 12, wherein the coating of the second plastic compound encloses the respective stator winding inside the space over at least the entire length of the respective space, measured along the axial direction, in the U-shaped manner in the circumferential direction.

14. The electrical machine according to claim 1, wherein the first and the second plastic compound together fill the at least one space completely.

15. The electrical machine according to claim 1, wherein the first and the second plastic compound are in each case formed by an injection molding compound of the first or the second plastic material, respectively.

16. The electrical machine according to claim 1, wherein:

the stator includes a ring-shaped stator body, and

the first plastic compound is arranged on an outer circumferential side of the stator body.

17. The electrical machine according to claim 1, wherein the first plastic compound embodies an outer coating on an outer circumferential side.

18. The electrical machine according to claim 1, wherein at least the first plastic compound protrudes axially from the space.

19. The electrical machine according to claim 1, wherein the first plastic compound at least partially limits the coolant distributor chamber and/or the coolant collector chamber.

20. The electrical machine according to claim 1, wherein the at least one cooling duct and the electrically insulating plastic are provided in at least one, or in each space between the two stator teeth, which are in each case adjacent in the circumferential direction.

21. The electrical machine according to claim 1, wherein at least one tube body is electrically insulated from the stator body, in particular from the stator teeth, by a first and/or second plastic compound.

22. The electrical machine according to claim 1, wherein:

the tube body is embodied as flat tube, and

in the cross-section perpendicular to the axial direction, at least one broad side of the flat tube extends substantially perpendicular to a radial direction.

23. The electrical machine according to claim 1, wherein the at least one stator winding is electrically insulated from the at least one cooling duct, which is embodied as the tube body, by a first and/or second plastic compound.

24. The electrical machine according to claim 1, wherein the at least one stator winding is embodied in such a way that it is electrically insulated from the coolant and/or from the stator body at least in an area inside the respective space during operation of the electrical machine by a first and/or second plastic compound.

25. The electrical machine according to claim 1, wherein:

the at least one cooling duct is arranged in the stator body and is formed by at least one aperture, through which the coolant can flow, and

the at least one aperture is completely limited or encased or surrounded by the electrically insulating plastic, or by the second plastic compound.

26. The electrical machine according to claim 25, wherein the at least one aperture, which forms the at least one cooling duct and which is arranged in the stator body, is embodied to be open towards the space and is closed in a fluid-tight manner by the electrically insulating plastic, or by the second plastic compound, which is arranged in the space.

27. The electrical machine according to claim 1, wherein the at least one cooling duct is arranged in the stator body in an area between two adjacent stator teeth with respect to the circumferential direction.

28. The electrical machine according to claim 1, wherein at least two cooling ducts, or all available cooling ducts, are embodied in such a way that, during operation of the electrical machine, the coolant guided through these cooling ducts flows from a first axial end section of the stator, or of the stator body, in a direction of a second axial end section of the stator or of the stator body, respectively, or vice versa.

29. The electrical machine according to claim 1, wherein that the stator windings are part of a distributed winding.

30. The vehicle, in particular a motor vehicle, comprising at least one electrical machine according to claim 1.