Cooling jacket assembly for cooling a rotating machine with flow guiding and reflector elements

Patent metadata

Field	Value
Publication number	US-12034352-B2
Application number	US-202017015827-A
Country	US
Kind code	B2
Filing date	Sep 9, 2020
Priority date	Sep 12, 2019
Publication date	Jul 9, 2024
Grant date	Jul 9, 2024

Abstract

A cooling jacket surrounding the stator of an electric machine, having an inlet and a plurality of outlets disposed at ends of the cooling jacket, distributed in circumferential direction and configured to create liquid jets exiting the cooling jacket in a radial direction towards end windings at the axial ends of the machine. Coolant liquid flow guiding elements within the cooling jacket are configured so as to create a circumferentially homogeneous or more homogenous axial liquid flow towards the liquid outlets and/or towards the liquid jet devices.

First claim

The invention claimed is:

1. A cooling assembly for cooling an electric machine having a rotational axis, a first axial end, a second axial end, and end windings at the first and second axial ends, wherein the cooling assembly comprises:
a cooling jacket surrounding the machine in a circumferential direction for receiving and guiding a cooling liquid, wherein the cooling jacket comprises:
at least one liquid inlet,
a plurality of liquid outlets arranged at at least one axial end of the cooling jacket, distributed in the circumferential direction around the cooling jacket, and spaced apart from the liquid inlet in, an axial direction parallel with the rotational axis,
liquid flow guiding elements for guiding a liquid inside the cooling jacket between the at least one liquid inlet and the liquid outlets, the liquid flow guiding elements formed as a series of walls arranged in a partial circumference around the cooling jacket and arranged at an angle to the circumferential direction and the axial direction such that part of a circumferential fluid flow from the at least one liquid inlet collides with successive liquid flow guiding elements and is directed in an axial direction away from the at least one liquid inlet and towards at least one liquid jet device, and
one or more liquid jet devices at the liquid outlets, the one or more liquid jet devices formed by axially oriented passages which receive the axially oriented liquid flow from the liquid flow guiding elements and create one or more axially oriented liquid jets exiting the cooling jacket at the liquid outlets, each of the liquid jet devices comprising one or more flow reflector elements shaped to reflect the one or more liquid jets from the axial direction to a radial direction and the reflected flow extending around an axial end of the machine and flowing towards the rotational axis.

2. The cooling assembly according to claim 1 , wherein the cooling jacket comprises a hollow cylinder which coaxially surrounds a stator of the machine, and wherein the hollow inner space of a hollow cylinder is filled with a cooling liquid.

3. The cooling assembly according to claim 1 , wherein the liquid flow guiding elements are located inside the cooling jacket and form walls which are straight, curved, or wriggled.

4. The cooling assembly according to claim 3 , wherein two or more liquid flow guiding elements in a form of walls are located between the at least one liquid inlet and the liquid outlets, and wherein said liquid flow guiding elements in the form of walls have different inclination angles between a longitudinal axis of each of the walls and the rotational axis.

5. The cooling assembly according to claim 4 , wherein the inclination angle is decreasing from the liquid flow guiding element closest to the at least one liquid inlet to the flow guiding element or to the flow guiding elements farthest from the at least one liquid inlet.

6. The cooling assembly according to claim 1 , wherein a distance between neighboring liquid flow guiding elements varies in the circumferential direction.

7. The cooling assembly according to claim 1 , wherein the liquid flow guiding elements have varying lengths and/or varying widths.

8. The cooling assembly according to claim 1 , wherein the liquid flow guiding elements are distributed irregularly in the axial direction and/or in the circumferential direction.

9. The cooling assembly according to claim 1 , wherein each of the flow reflector elements comprises a reflector surface which is inclined with regard to the rotational axis and directs flow from the axial direction into the radial direction, and wherein a circumferential extension of each reflector surface about the rotational axis is between ⅓ and 1/500 of a circumference of the machine.

10. The cooling assembly according to claim 1 , wherein restrictions of the one or more liquid jet devices is created by fins or walls disposed circumferentially around the cooling jacket and extending parallel to the rotational axis, and wherein the one or more liquid jet devices are formed in between neighboring fins or walls of said fins or walls.

11. The cooling assembly according to claim 1 , wherein one or more flow reflector elements have a ring shape or a shape of a ring segment, and wherein the ring is coaxially surrounding the rotational axis.

12. The cooling assembly according to claim 11 , wherein each of the flow reflector elements has a reflector surface which is curved in an axial section of the machine and the reflector surface redirects the liquid lets from the axial direction into the radial direction.

13. The cooling assembly according to claim 12 , wherein in an axial section of the machine, each of the flow reflector elements has a reflector surface which is curved and has a form of at least one quarter of a circle, so that the flow reflector element is forming a grooving.

14. An electric machine comprising:
a stator positioned around a rotational axis of the machine;
end windings at axial ends of the stator; and
a cooling jacket surrounding the stator in a circumferential direction for receiving and guiding a cooling liquid,
wherein the cooling jacket comprises:
at least one liquid inlets,
a plurality of liquid outlets, the liquid outlets being disposed at at least one axial end of the cooling jacket, distributed in the circumferential direction, and spaced apart from the at least one liquid inlet in an axial direction,
liquid flow guiding elements for guiding a liquid inside the cooling jacket between the at least one liquid inlet and the liquid outlets, the liquid flow guiding elements formed as a series of walls arranged in a partial circumference around the cooling jacket and arranged at an angle to the circumferential direction and the axial direction such that part of a circumferential fluid flow from the at least one liquid inlet collides with successive liquid flow guiding elements and is directed in an axial direction away from the at least one liquid inlet and towards the liquid outlets, and
one or more liquid jet devices at the liquid outlets, the one or more liquid jet devices formed by axially oriented passages which receive the axially oriented liquid flow from the liquid flow guiding elements and create one or more axially oriented liquid jets exiting the cooling jacket at the liquid outlets, each of the liquid jet devices comprising one or more flow reflector elements shaped to reflect the one or more liquid jets from the axial direction to a radial direction and the reflected flow extending around an axial end of the machine and flowing towards the rotational axis.

15. The machine of claim 14 , wherein the liquid flow guiding elements are configured to create a circumferentially homogeneous or more homogenous axial liquid flow towards the liquid outlets and/or towards the liquid jet devices.

16. The machine of claim 14 , wherein two or more liquid flow guiding elements in a form of walls are located between the at least one liquid inlet and the liquid outlets, and wherein said liquid flow guiding elements in the form of walls have different inclination angles between a longitudinal axis of each of the walls and the rotational axis.

17. The machine of claim 14 , wherein each of the flow reflector elements comprises a reflector surface which is inclined with regard to the rotational axis and directs an axial flow into a radial flow, and wherein a circumferential extension of each reflector surface about the rotational axis is between ⅓ and 1/500 of a circumference of the machine.

18. The machine of

Assignees

• Dana Belgium Nv

Inventors

• Vanhee Steven

Classifications

• H02K9/19 Primary

  for machines with closed casing and closed-circuit cooling using a liquid cooling medium, e.g. oil · CPC title

• H02K5/18

  with ribs or fins for improving heat transfer · CPC title

• H02K5/20 Primary

  with channels or ducts for flow of cooling medium · CPC title