Stator for an axial flux machine, in particular of a motor vehicle, and axial flux machine

Abstract

The invention relates to a stator (10) for an axial flux machine, having pole elements (12), which follow one another in the circumferential direction of the stator (10), for forming respective electrical poles of the axial flux machine, wherein the respective pole element (12) has: two pole shoes (20, 22) lying opposite one another in the axial direction of the stator (10); and a stator tooth (24) arranged between the pole shoes (20, 22) in the axial direction of the stator (10) and formed from multiple segments (58) made of a metal material, with a winding (26) of the stator (10) being wound around said stator tooth; wherein the stator tooth (24) of at least one of the pole elements (12), in its interior (28), has a cooling channel (30) through which a coolant for cooling the stator (10) is able to flow and which, along its circumferential direction, is completely circumferentially surrounded by the stator tooth (24) of the at least one pole element (12). According to the invention, the stator tooth (24) is overmolded with an overmolding (52) made of plastic, said overmolding having an opening (54) which is arranged so as to overlap the inlet opening (38) and through which the coolant is able to flow and / or an opening (56) which is arranged so as to overlap the outlet opening (39) and through which the coolant is able to flow, wherein the opening (54, 56), along its circumferential direction, is completely surrounded by a wall region (WB1, WB2) of the overmolding (52), and wherein the winding (26) is supported directly against at least part of the wall region (WB1, WB2) in the axial direction of the stator (10), such that the throughflow openings (38, 39) are kept free from the winding (26) by the respective wall region (WB1, WB2) and thus by the overmolding (52).

Description

[0001] 2024P00686WG

[0002] 1

[0003] Mercedes-Benz Group AG

[0004] Stator for an axial flux machine, in particular for a motor vehicle, as well as axial flux machine

[0005] The invention relates to a stator for an axial flux machine, in particular for a motor vehicle, according to the preamble of claim 1. Furthermore, the invention relates to an axial flux machine, in particular for a motor vehicle.

[0006] DE 10 102022 004 802 A1 discloses a method for manufacturing a stator of an axial flux machine. DE 102021 002 941 A1 discloses a pole element for providing an electrical pole of an axial flux machine. EP 4 327 438 A1 discloses a method and a system for rod support with integrated cooling. Furthermore, an electric machine is known from EP 2 606 561 B1. The prior art also includes DE 102014 221 648 A1, DE 11 2020 002 759 B5, EP 2 951 907 B1, EP 3 764 526 A1, and EP 2 396 871 B1.

[0007] WO 2021 / 164 946 A1 also shows a stator assembly and a rotor assembly of an axial flux machine, the stator assembly comprising several stator cores wound with a wire coil. An internal fluid channel for holding a cooling fluid is provided in the stator core.

[0008] From DE 102021 108 957 A1 an electrical machine with a rotor and stator is known, wherein the stator has a stator body with stator winding, between which an insulating coating is provided, which runs out in a local recess of the stator body towards the rotor and does not protrude.

[0009] DE 102023 109 865 A1 relates to a stator of an axial flux machine, comprising a stator tooth and a conductor wound in turns, wherein spacers serve to keep a cooling channel clear between the stator tooth and the windings. 2024P00686WG

[0010] 2

[0011] The subsequently published document DE 102023 119 729 A1 discloses an axial flux machine with a stator in a housing, in which the stator cores with coils are arranged along a circular circumference, such that a main cooling channel is formed between the housing and the coils and / or between adjacent coils. Furthermore, at least one secondary cooling channel is provided in the stator cores.

[0012] WO 2025 / 140 999 A1 discloses, as a subsequently published prior art, a stator of an electric motor with teeth on which coils are arranged. In this design, at least one passage through the tooth is provided for cooling the stator with a cooling fluid, allowing the cooling fluid to pass through the tooth.

[0013] The object of the present invention is to create a stator for an axial flux machine, in particular for a motor vehicle, and an axial flux machine, in particular for a motor vehicle, in such a way that a particularly advantageous cooling of the stator can be realized.

[0014] This problem is solved by a stator with the features of claim 1 and by an axial flux machine with the features of claim 7. Advantageous embodiments with expedient further developments of the invention are specified in the remaining claims.

[0015] A first aspect of the invention relates to a stator for an axial flux machine, particularly for a motor vehicle. The axial flux machine is an electric machine and is therefore also referred to as an electric machine. The axial flux machine is also called an axial flux motor (AFM). In its fully manufactured state, the axial flux machine comprises the stator. For example, in its fully manufactured state, the axial flux machine has a rotor, which can be driven, for example, by means of the stator and is thus rotatable about a machine axis of rotation relative to the stator. In particular, the axial flux machine can provide drive torques via its rotor for the, in particular, purely electric propulsion of the electric motor vehicle. The motor vehicle thus comprises the axial flux machine in its fully manufactured state and can be driven, in particular purely electric, by means of the axial flux machine.Preferably, the axial flux machine is a high-voltage component whose electrical voltage, in particular its operating and / or rated voltage, is preferably greater than 50 volts, particularly greater than 60 volts, and most preferably several hundred volts. The stator, whose axial direction coincides with the machine's axis of rotation, has pole elements for forming the respective electrical poles of the axial flux machine. The pole elements are arranged successively in the circumferential direction of the stator, whose radial direction is perpendicular to the axial direction of the stator and thus perpendicular to the machine's axis of rotation. Where the radial direction is mentioned before and below, this refers, unless otherwise specified, to the radial direction of the stator. Where the axial direction is mentioned before and below, this refers, unless otherwise specified, to the axial direction of the stator.When the circumferential direction is mentioned before and below, unless otherwise specified, this refers to the circumferential direction of the stator. The circumferential direction of the stator runs around the axial direction and thus around the machine's axis of rotation, extending in a plane perpendicular to the axial direction and thus perpendicular to the machine's axis of rotation. In particular, the pole elements are arranged uniformly distributed around the circumference.

[0016] Each pole element has, in particular, exactly two pole shoes axially opposed to each other. For example, the respective pole shoes of each pole element are spaced apart axially. For example, each pole shoe is made of a soft magnetic material. For example, each pole shoe is made of a soft magnetic composite material. For example, the soft magnetic composite material has a matrix made of a plastic, and therefore also referred to as a plastic matrix, and particles embedded in the matrix, which are preferably made of a metallic material, in particular a metallic soft magnetic material.

[0017] Each pole element further features a stator tooth arranged axially between the pole shoes, which is also simply referred to as a tooth, rod, or stator bar. The stator tooth of each pole element is formed from several segments. Each segment is made of a metallic material, in particular a metallic soft magnetic material. For example, the metallic material from which the segment is formed is a sheet metal lamination, so that the segment is formed as a sheet metal segment. Thus, the stator tooth is formed by a stack of laminated laminations. At least one stator winding is wound around each stator tooth of the pole element. It is conceivable that several stator windings are wound around each stator tooth of the pole element.The winding is made of copper, for example, and is therefore also called a copper winding. A magnetic field can be generated, or provided, by means of the winding, whereby the rotor can be driven by means of the magnetic field and thus rotated around the machine's axis of rotation relative to the stator.

[0018] It is conceivable that the segments are arranged one after the other in the axial direction of the stator, that is, consecutively. Furthermore, it would be conceivable that the segments are arranged one after the other in the circumferential direction of the stator. It would also be conceivable that the segments are arranged one after the other in the radial direction of the stator, that is, consecutively.

[0019] To achieve particularly advantageous stator cooling, the invention provides that the stator tooth of at least one of the pole elements has an internal cooling channel through which a coolant flows for cooling the stator. This cooling channel is completely surrounded along its circumference by the stator tooth of the at least one pole element. Where the stator tooth is mentioned before and below, this refers, unless otherwise specified, to the stator tooth of the at least one pole element. Where the cooling channel is mentioned before and below, this refers, unless otherwise specified, to the cooling channel located and thus extending within the stator tooth. The cooling channel is also referred to as the first cooling channel. Where the cooling channel is mentioned before and below, this refers, unless otherwise specified, to the first cooling channel.The circumferential direction of the cooling channel means the following: The cooling channel is designed to allow coolant flow in a specific direction. This means that during operation of the axial flux machine, the coolant flows through the cooling channel in the direction of flow, with the circumferential direction of the cooling channel running around the direction of flow and lying in a plane perpendicular to the direction of flow. 2024P00686WÖ.

[0020] 5

[0021] In particular, it is provided that the cooling channel is completely surrounded by the stator tooth along its entire circumference, extending within the stator tooth. Preferably, the coolant is a cooling fluid. Preferably, the coolant is a liquid, also referred to as a cooling fluid. Preferably, the coolant is an oil, also referred to as a cooling oil. Preferably, the stator contains the coolant, which is thus preferably a component of the stator.

[0022] The cooling channel and the coolant allow the stator tooth, and thus the stator, to be cooled particularly effectively and efficiently, as the coolant can transport heat away from the interior of the stator tooth in a particularly advantageous way as it passes through the cooling channel.

[0023] The characteristic that the pole elements are designed or intended to form electrical poles of the axial flux machine means that electrical poles of the axial flux machine are to be formed or have been formed by the pole elements. In particular, at least during the aforementioned operation of the axial flux machine, electrical poles of the axial flux machine are formed by the pole elements, especially such that the first of the electrical poles are the electrical north poles (N) of the axial flux machine and the second of the electrical poles are the electrical south poles (S) of the axial flux machine.

[0024] The invention is based in particular on the following findings and considerations: Preliminary tests have shown that high material temperatures can occur in the respective segments of each stator tooth, especially due to magnetization losses, which can negatively affect the efficiency and potential continuous power output of the axial flux machine. In conventional solutions, the coolant flows around the stator teeth and the winding, with the coolant primarily flowing around the winding, particularly because the winding is wound around the respective stator tooth. The stator tooth, which is located inside the winding and is therefore, for example, designed as a laminated core or formed by a laminated core, is surrounded, for example, by electrical insulation, which is formed, for example, from a plastic and / or by overmolding the respective stator tooth.This thermally isolates the stator tooth from the coolant flowing around it. The aforementioned problems and disadvantages can now be avoided because the coolant, i.e., a flow of coolant (also referred to as a current), is directed into the cooling channel and thus into the interior of the stator tooth, allowing it to flow through the tooth and its interior. Specifically, the cooling channel runs centrally through the stator tooth, enabling centralized and therefore effective and efficient cooling. This allows for efficient cooling of the stator tooth segments, and thus the core of the tooth itself. Compared to conventional cooling methods, lower segment temperatures can be achieved, thereby improving the efficiency of the axial flux machine.Compared to conventional solutions, improved cooling can be achieved, which prevents exceeding component limit temperatures, especially of the stator tooth, at higher power levels, thus enabling an increase in the continuous power output of the axial flux machine.

[0025] To enable particularly effective and efficient cooling of the stator tooth and thus the stator as a whole, the invention provides that the cooling channel, in particular, has an inlet opening through which the cooling channel opens into or onto the surrounding area of ​​the stator tooth. The coolant, especially from the surrounding area of ​​the stator tooth, can be introduced into the cooling channel and thus into the interior of the stator tooth via this inlet opening. The inlet opening is formed in a first surface of the stator tooth that points radially outwards or inwards and terminates, for example, radially outwards or inwards at this first surface.

[0026] According to the invention, to achieve particularly advantageous cooling, the cooling channel, in particular, has an outlet opening through which the cooling channel opens into or onto the surroundings of the stator tooth when considering only the stator tooth. The coolant can be discharged from the cooling channel and thus from the interior of the stator tooth via the outlet opening. The outlet opening is formed in a second surface of the stator tooth, the second surface being radially oriented away from the first surface. Thus, if the first surface faces outwards in a radial direction, the second surface faces inwards in a radial direction. Conversely, if the first surface faces inwards in a radial direction, the second surface faces outwards in a radial direction. This allows for particularly advantageous cooling. 2024P00686WÖ

[0027] 7. Advantageously, heat is transported away from the interior of the stator tooth, so that the stator can be cooled particularly advantageously.

[0028] Preferably, the cooling channel has exactly two flow openings through which the coolant flows, and through which the cooling channel opens onto or into the vicinity of the stator tooth when considering only the stator tooth. The first of these flow openings is the inlet opening, and the second is the outlet opening. This allows for effective and efficient cooling.

[0029] According to the invention, the stator tooth is overmolded with the aforementioned overmolding, which is made of plastic and therefore also referred to as plastic overmolding, thus surrounding the stator tooth. The overmolding has a first opening arranged in overlap with the inlet opening and through which the coolant flows, and / or a second opening arranged in overlap with the outlet opening and through which the coolant flows. Thus, for example, the coolant can be supplied to the inlet opening via the first opening, and therefore flow to the inlet opening via the first opening. Furthermore, for example, the coolant can be discharged from the outlet opening and thus from the cooling channel via the second opening. It has proven particularly advantageous if the first opening and / or the second opening is completely surrounded along its circumferential direction by a respective wall region of the overmolding.The circumferential direction of each opening means the following: The coolant flows through each opening in a flow direction also referred to as the opening direction, so that the coolant flows through the opening in this direction during operation of the axial flux machine. The circumferential direction of each opening runs around the opening direction itself. It has proven particularly advantageous if the winding is supported directly against at least part of the respective wall area in the axial direction. This prevents, for example, the winding from obstructing the opening. Consequently, it ensures that the coolant can flow through the cooling channel particularly efficiently, resulting in highly effective cooling.The flow openings are kept free of the winding (26) by means of the respective wall area and thus by means of the overmolding. 2024P00686WG.

[0030] 8

[0031] Another embodiment is characterized in that the cooling channel extends in a straight line, i.e., along an imaginary straight line from the inlet opening to the outlet opening and vice versa. This allows heat to be dissipated from the interior of the stator tooth particularly effectively. In a further, particularly advantageous embodiment of the invention, the cooling channel extends in a straight line parallel to the radial direction, and thus along the imaginary straight line from the inlet opening to the outlet opening and vice versa, thereby allowing the stator tooth, and thus the stator, to be cooled particularly effectively.

[0032] In achieving particularly effective cooling, it has proven especially advantageous to maintain the winding at a distance from the stator tooth in the radial direction of the stator by means of overmolding. This prevents the winding from excessively impeding the flow of coolant through the cooling channel, thus enabling effective stator cooling.

[0033] Another embodiment is characterized by the fact that the cooling channel is arranged in the center of the stator tooth when viewed in the axial direction. This allows heat to be dissipated particularly effectively from the interior of the stator tooth.

[0034] Finally, it has proven particularly advantageous for achieving a particularly beneficial cooling of the stator if the cooling channel has a rectangular flow cross-section through which the coolant can flow.

[0035] A second aspect of the invention relates to an axial flux machine, also known as an axial flux motor (AFM), with a stator according to the first aspect of the invention. Advantages and advantageous embodiments of the first aspect of the invention are to be regarded as advantages and advantageous embodiments of the second aspect of the invention, and vice versa.

[0036] Further advantages, features, and details of the invention will become apparent from the following description of a preferred embodiment and from the drawing. The features and combinations of features mentioned above in the description, as well as those mentioned below in the figure description, 2024P00686WQ

[0037] The features and combinations of features shown in Figure 9 and / or in the figures alone are not only usable in the combinations shown, but also in other combinations or on their own, without leaving the scope of the invention.

[0038] The drawing shows in:

[0039] Fig. 1 shows a partial schematic cross-sectional view of a stator for an axial flux machine, in particular of a motor vehicle;

[0040] Fig. 2 shows a schematic perspective view of a pole element of the stator;

[0041] Fig. 3 shows a schematic longitudinal section view of the pole element along a section plane parallel to the axial direction of the stator;

[0042] Fig. 4 shows a schematic sectional view of the pole element along a section plane BB shown in Fig. 3;

[0043] Fig. 5 shows another schematic sectional view of the pole element along the section plane BB shown in Fig. 3;

[0044] Fig. 6 shows a schematic and enlarged representation of an area of ​​the pole element designated D in Fig. 3;

[0045] Fig. 7 shows a schematic top view of the pole element;

[0046] Fig. 8 shows a partial schematic sectional view of the pole element along a section plane C shown in Fig. 7; and

[0047] Fig. 9 shows a schematic and enlarged representation of an area of ​​the pole element designated E in Fig. 7.

[0048] In the figures, identical or functionally equivalent elements are provided with the same reference symbols.

[0049] Fig. 1 shows a partial schematic cross-sectional view of a stator 10 for an axial flux machine, in particular of a motor vehicle. In particular, Fig. 1 shows the stator 10 in a schematic cross-sectional view along a 2024P00686WQ

[0050] 10

[0051] The cross-sectional plane coincides with the plane of Fig. 1. In its fully assembled state, the axial flux machine comprises a stator 10 and a rotor, which can be driven by the stator 10 and is thus rotatable about a machine axis of rotation relative to the stator 10. The axial flux machine can provide drive torques via its rotor for, in particular, purely electric, propulsion of the motor vehicle. The stator 10, whose axial direction coincides with the machine axis of rotation, has several pole elements 12. The axial direction of the stator 10 is illustrated in Fig. 1 by a double arrow 14 and runs perpendicular to the plane of Fig. 1, with the aforementioned cross-sectional plane being perpendicular to the axial direction of the stator 10.The pole elements 12 are arranged successively in the circumferential direction of the stator 10, whose radial direction is perpendicular to the axial direction of the stator 10 and thus perpendicular to the machine's axis of rotation. The radial direction of the stator 10 is illustrated by a double arrow 16 and runs perpendicular to the machine's axis of rotation and thus perpendicular to the axial direction of the stator 10 and in the plane of Fig. 1. The circumferential direction of the stator 10 runs around the axial direction of the stator 10 and thus around the machine's axis of rotation, with the circumferential direction of the stator 10 running in the plane of Fig. 1. The circumferential direction of the stator 10 is illustrated by a double arrow 18. When the axial direction is mentioned before and after, this refers, unless otherwise specified, to the axial direction of the stator 10.When the radial direction is mentioned before and below, this refers, unless otherwise specified, to the radial direction of the stator 10. When the circumferential direction is mentioned before and below, this refers, unless otherwise specified, to the circumferential direction of the stator 10.

[0052] Fig. 2 shows a schematic perspective view of one of the pole elements 12. The preceding and following descriptions of this one pole element 12 can readily be applied to the other pole elements 12 and vice versa. In particular, the pole elements 12 are arranged uniformly distributed in the circumferential direction.

[0053] Each pole element 12 has, in particular, two pole shoes 20 and 22, which are axially opposed to each other and, in particular, spaced apart from each other. Furthermore, each pole element 12 has a stator tooth 24, which is arranged axially between the respective pole shoes 20 and 22 of the respective pole element 12. The respective stator tooth 24 is formed from several segments arranged radially one above the other, the respective segment being made of a metallic material, in particular a metallic soft magnetic material. Preferably, the respective 20, 22 is made of a soft magnetic composite material.The soft magnetic composite material, for example, comprises a matrix formed from a plastic and therefore also referred to as a plastic matrix, as well as particles embedded in the matrix and formed from a metallic material, in particular a soft magnetic metallic material. It is particularly evident from Fig. 2 that at least one winding 26 of the stator 10 is wound around, i.e., wound, each stator tooth 24.

[0054] In order to achieve particularly advantageous cooling of the stator teeth 24, and thus of the pole elements 12 and the stator 10, each stator tooth 24 has, as can be seen particularly well in Figures 3 to 5, a cooling channel 30 in its interior 28, through which a coolant flows for cooling the stator 10. This cooling channel is completely surrounded by the respective stator tooth 24 along its circumferential direction, illustrated in Figure 4 by an arrow 32. In Figures 1 and 4, arrows 40 illustrate a first flow of the coolant through the respective cooling channel 30 and thus through the respective stator tooth 24. In other words, arrows 40 illustrate the coolant flowing through the respective cooling channel 30 and thus the respective first flow of the coolant passing through the respective cooling channel 30.In other words, arrows 40 illustrate the initial mass flow of the coolant through each cooling channel 30. Arrows 40 also illustrate the direction of flow in which the coolant can flow through, or flows through, the cooling channel 30 during operation of the axial flux machine. For example, during operation, the stator 10 is driven by the rotor and thereby rotated about the machine's axis of rotation relative to the stator 10. Similarly, during operation, a magnetic field is generated and provided by the winding 26, which, for example, drives the rotor and thereby rotates it about the machine's axis of rotation relative to the stator 10. Arrows 32 and 40 indicate that the circumferential direction of each cooling channel 30 is around the respective flow direction. 2024P00686WG.

[0055] 12

[0056] As can be seen from Fig. 4, each stator tooth 24 has a first surface 34 and a second surface 36. This means that each stator tooth 24 has a total surface area on its outer circumference, with surface 34 being a first part of the total surface area and surface 36 a second part. Surfaces 34 and 36 point away from each other in a radial direction, such that the first surface 34 points outwards and surface 36 points inwards. Each cooling channel 30 has exactly two flow openings through which the coolant can flow, namely a first flow opening 38 and a second flow opening 39.The respective flow opening 38 is formed in the respective surface 34, and the respective flow opening 39 is formed in the respective surface 36 of the respective stator tooth 24. In the first of the pole elements 12 of the stator 10, and thus also in the pole element 12 shown in Figures 2 to 9, the flow opening 38 is an inlet opening, also referred to as an inlet or inlet, and the flow opening 39 is an outlet opening, also referred to as an outlet or outlet. In the second of the pole elements 12 of the stator 10, the flow opening 38 is the outlet opening and the flow opening 39 is the inlet opening. The coolant can be introduced into the respective cooling channel 30 via the respective inlet opening of the respective cooling channel 30 and thus into the respective interior 28 of the respective stator tooth 24, particularly when considering only the respective stator tooth 24 from its surroundings.The coolant can be discharged from the respective cooling channel 30 and thus from the respective interior 28 of the respective stator tooth 24 via the respective outlet opening of the respective cooling channel 30 and can in particular be directed into the environment.

[0057] As can be seen particularly well in Fig. 4, each cooling channel 30 extends in a straight line from the respective flow opening 38 to the respective flow opening 39 and vice versa, such that the respective cooling channel 30 extends parallel to the radial direction in a straight line from the respective flow opening 38 to the respective flow opening 39 and vice versa. The flow openings 38 and 39 of the respective cooling channel 30 are arranged at the respective ends of the cooling channel 30.

[0058] Arrows 40 in Fig. 1 show that, particularly during the aforementioned operation of the axial flux machine, the coolant, i.e., the first mass flows, flows through the cooling channels 30 of the stator teeth 24. 2024P00686WG

[0059] 13 or flow through it, such that the coolant or the first mass flows meander through the cooling channels 30 of the stator teeth 24 in a first plane perpendicular to the axial direction. This allows for effective and efficient cooling of the stator 10.

[0060] Figure 1 also shows that the stator 10 has a second cooling channel 42 through which the coolant flows. This second cooling channel runs in a meandering pattern around the stator teeth 24 on the outside of the stator teeth 24, in a second plane perpendicular to the axial direction. This second plane can be, for example, the first plane or parallel to the first plane and spaced axially from the first plane. Each cooling channel 30 opens into the second cooling channel 42, particularly via its respective outlet opening. Each cooling channel 30 is also referred to as the first cooling channel.

[0061] As can also be seen from Fig. 1, the stator teeth 24 are arranged successively in the circumferential direction of the stator 10. In particular, the stator teeth 24 are arranged uniformly distributed in the circumferential direction. Specifically, the stator teeth 24, especially when considered in pairs, are arranged circumferentially spaced apart from one another such that a circumferentially extending distance A is provided between each pair of stator teeth 24 adjacent to one another. In other words, the stator teeth 24, especially when considered in pairs, are arranged circumferentially at a respective circumferentially extending distance A from one another.

[0062] The stator 10 comprises a housing 41, also referred to as a stator housing, in which the pole elements 12 are arranged. Each stator tooth 24 is arranged radially spaced from a first wall W1 of the housing 41, and each stator tooth 24 is arranged radially spaced from a second wall W2 of the housing 41. Thus, a second space is provided radially between each stator tooth 24 and wall W1, and a third space is provided radially between each stator tooth 24 and wall W2. The second cooling channel 42 is formed by the first space A, the second space A, the third space A, the walls W1 and W2, and blocking elements 44. 2024P00686WG

[0063] 14 which are also referred to as blockers or flow blockers. The cooling channel 42 is designed such that the second cooling channel 42 meanders in the aforementioned second plane, meaning that, particularly during the operation of the axial flux machine, the coolant flows through the second cooling channel 42 in a meandering pattern, as viewed in the second plane.

[0064] In Fig. 1, arrows 46 illustrate a second flow of coolant through the second cooling channel 42. In other words, arrows 46 illustrate the coolant flowing through the second cooling channel 42. Put another way, arrows 46 illustrate a second mass flow of coolant passing through the second cooling channel 42. The coolant flowing through the second cooling channel 42 meanders through the second cooling channel 42 and flows around the outside of the stator teeth 24.

[0065] For example, the cooling channels 30 and 42 are designed with respect to their respective flow cross-sections such that the first mass flow rate of the coolant flowing through the first cooling channel 30 during operation of the axial flux machine is lower than the second mass flow rate of the coolant flowing through the second cooling channel 42 during operation of the axial flux machine. It is conceivable that the ratio of the respective first mass flow rate to the second mass flow rate lies in the range of 1 / 9 to 3 / 7 inclusive. Alternatively or additionally, it is conceivable that the respective first mass flow rate is at least 10% and at most 30% of the second mass flow rate.

[0066] In Fig. 1, an arrow 48 represents the total mass flow rate of the coolant, where, for example, the first mass flow rates and the second mass flow rate combine to form the total mass flow rate. The stator 10, for example, has a supply channel 50 common to the cooling channels 30 and 42, through which the cooling channels 30 and 42 can be supplied with coolant. It can be seen that the supply channel 50 runs, for example, within the housing 41.

[0067] Figures 3 and 4 show that the stator tooth 24 is overmolded with a plastic overmolding, also referred to as a plastic overmolding, whereby the stator tooth 24 is surrounded by the overmolding 52. Figure 4 shows 2024P00686WÖ

[0068] It can be seen that the overmolding 52 has a first opening 54 arranged in overlap with the flow opening 38, through which the coolant can flow in the direction of flow. If the flow opening 38 is the inlet opening, then the inlet opening and thus the cooling channel 30 can be supplied with coolant via the first opening 54; therefore, the coolant can be supplied to the inlet opening and thus to the cooling channel 30 via the opening 54. If the flow opening 38 is the outlet opening, then, for example, the opening 54 can discharge the coolant from the outlet opening and thus from the cooling channel 30. Alternatively or additionally, the overmolding 52 has a second opening 56 arranged in overlap with the flow opening 39. If the flow opening 39 is the outlet opening, then the coolant can be discharged from the outlet opening and thus from the cooling channel 30 via the opening 56.If the flow opening 39 is the inlet opening, the coolant can be supplied to the inlet opening and thus to the cooling channel 30 via the opening 56. In this case, the coolant can flow through the opening 56 in the direction of flow. Therefore, the respective openings 54 and 56, viewed particularly along the direction of flow, are arranged in line with or alongside the respective flow openings 38 and 39.

[0069] In the embodiment shown in Fig. 4, each opening 54, 56 is completely surrounded along its respective circumferential direction by a respective wall region WB1, WB2 of the overmolding 52. The respective circumferential direction of each opening 54, 56 runs around the respective flow direction in which the coolant can flow through the respective opening 54, 56 or flows through it during operation of the axial flux machine. It can be seen from Fig. 4 that the winding 26 is supported in the axial direction directly against at least a part of the respective wall region WB1, WB2. In the embodiment shown in Fig. 4, the winding 26 is provided that, viewed in the axial direction, it is supported on both sides of the respective opening 54, 56 directly against the respective wall region WB1, WB2.The respective wall sections WB1 and WB2, and thus the overmolding 52, keep the flow openings 38 and 39 free from the winding 26. In other words, this prevents the winding 26 from excessively overlapping the flow openings 38 and 39, thereby allowing advantageous coolant flow through the cooling channel 30. The aforementioned segments of the respective stator tooth 24, also referred to as individual segments, are visible in Fig. 5 and are labelled 58 there. For example, the segments 58 are connected to each other by means of the overmolding 52.

[0070] Figure 3 shows that, for example, the cooling channel 30 is located in the center of the stator tooth 24 when viewed axially. Figure 3 also shows that the cooling channel 30 has a rectangular cross-section through which the coolant flows.

[0071] The second cooling channel 42 and the second coolant flow passing through it create an external flow around the stator teeth 24, which are also referred to as individual teeth or are designed as individual teeth. This external flow around the stator teeth 24 primarily serves to cool the winding 26, which is, for example, a copper winding. A cooling fluid gap between the winding 26 and the adjacent stator tooth 24, through which the coolant can flow, has a height of, for example, 0.5 mm to 1 mm. The respective cooling channel 30 is flow-parallel to the cooling channel 42, and the coolant flowing through the respective cooling channel 30 passes at least substantially centrally through the respective stator tooth 24.

[0072] The respective cooling channel 30 is formed, for example, by a recess, particularly central, in the segments 58 of the respective stator tooth 24, which are designed in particular as individual laminations. This recess is preferably located centrally in the respective segment, in particular in a respective lamination section of the respective segment.

[0073] In other words, at least some of the segments 58 of the respective stator tooth 24 have a recess designed as a through-opening, wherein the recesses of the respective stator tooth 24 are arranged successively in the radial direction and overlap each other, such that the recesses of the respective stator tooth 24 form the respective cooling channel 30. During a manufacturing process of the respective stator tooth 24, also referred to as an assembly process or designed as an assembly process, the segments 58 are stacked, for example, in a process also referred to as stacking, which occurs during or through the 2024P00686WÖ

[0074] 17

[0075] The segments are stacked on top of each other. For example, the recesses of the segments 58 of the respective stator tooth 24 are used as guides during stacking, in particular to position the segments 58 of the respective stator tooth 24 relative to each other. It is particularly evident from Fig. 5 that the respective cooling channel 30 runs continuously through the respective stator tooth 24, which is designed as a laminated core or formed by a laminated core.

[0076] To prevent, for example, the flow openings 38 and 39 of the respective cooling channel 30 from being excessively covered by the winding 26, the overmolding 52 has fins 60, which are also referred to as guide fins or winding guide fins. The respective stator tooth 24 is overmolded with the overmolding 52 and thus provided with it. This overmolding is carried out, for example, by an injection molding process in which the respective stator tooth 24 is overmolded with the overmolding 52 and thus provided with it. The fins 60 are produced during this injection molding process. The fins 60 guide the winding 26, i.e. a wire which is wound around the stator tooth 24 and thereby forms the winding 26, as closely as possible around the flow openings 38 and 39 and preferably around the openings 54 and 56 of the overmolding 52.

[0077] Preferably, the flow cross-sections of the cooling channels 30 and 42 are matched, particularly to each other, such that the respective first mass flow of the coolant passing through the respective cooling channel 30 is sufficient to advantageously cool the respective stator tooth 24. For example, a ratio of the respective first mass flow to the second mass flow corresponds to a ratio of magnetic losses in the stator tooth 24 to electrical losses of the winding 26. For example, at least substantially 10% to 30% of the total mass flow passes through the respective cooling channel 30.

[0078] The respective recess of each segment 58, designed as a through-opening, is, for example, a central and / or mid-center recess, which, viewed axially, is located in the middle of the respective segment 58 and thus of the stator tooth 24. In particular, all segments 58 of the respective stator tooth 24 have such a recess designed as a through-opening, so that the recesses of, in particular all, segments 58 form the respective cooling channel 30.

[0079] The cooling channel 30, in particular its flow cross-section, has a circumferential width and an axial depth, wherein the ratio of width to depth is preferably in a range of 2:1 to 4:1 inclusive.

[0080] Fig. 6 shows an enlarged view of the area designated D in Fig. 3. A winding pitch a, according to which the winding 26 is wound around the stator tooth 24, is visible in Fig. 6. The cooling channel 30 is bounded on both sides in the axial direction by axially opposed, flat surfaces F1 and F2 of the stator tooth 24. The respective surfaces F1 and F2 form an angle with the axial direction that corresponds to the winding pitch a, according to which the winding 26 is wound around the stator tooth 24 during a winding process.

[0081] The overmolding 52 is arranged, for example, between the respective pole shoe 20, 22 and the stator tooth 24 and / or between the winding 26 and the stator tooth 24. For example, the overmolding 52 acts as electrical insulation, by means of which the respective pole shoe 20, 22 is electrically insulated from the stator tooth 24 and / or the stator tooth 24 is electrically insulated from the winding 26. In the area of ​​the cooling channel 30, turns of the winding 26 are guided around the flow openings 38 and 39 of the cooling channel 30, which are designed as cooling channel openings. An advantageous distance between these turns is achieved by the fins 60, by means of which the aforementioned turns are kept at a distance from each other, particularly in the axial direction. The respective fin 60 is, for example, a local or point thickening of the overmolding 52, particularly in the area around the respective flow opening 38, 39.

[0082] As can be seen from Fig. 7, for example, one of the fins 60 is attached to each side of the cooling channel 30 in the circumferential direction, so that the fins 60 connect to the cooling channel 30 on both sides along its width, and in particular to the narrow sides of the cooling channel 30, whose narrow sides are arranged between the surfaces F1 and F2, which are designed as wide sides. Again with other 2024P00686WQ

[0083] 19

[0084] In other words, the fins 60 are arranged at opposite ends of the cooling channel 30 in the circumferential direction, which terminates at these opposite ends. Specifically, these ends of the cooling channel 30 are the ends of the flow cross-section of the cooling channel 30, also referred to simply as the cross-section. As can be seen in Fig. 7, each fin 60 tapers to a point on its side facing away from the cooling channel 30 in the circumferential direction. The longitudinal extent of each fin 60 is aligned, at least substantially, parallel to the winding pitch a.For example, each fin 60, viewed in a plane parallel to the axial direction, has a base surface that is at least substantially triangular and tapers, for example, along a fin height of the respective fin 60, which extends particularly in a radial direction, especially away from the stator tooth 24. A maximum base surface width of the respective fin 60, in particular the respective base surface of the respective fin 60, is formed, for example, orthogonally to a longitudinal surface of the cooling channel 30 or the flow cross-section of the cooling channel 30 and preferably corresponds to the width of the cooling channel 30. The fin height of the respective fin 60, which is also simply referred to as the height and extends, for example, in a radial direction, is preferably at least 50% of a wire height, in particular of the winding 26.

[0085] Fig. 8 shows a section of the pole element 12 in a section plane labeled CC. The fins 60 of the overmolding 52 are particularly well shown in Fig. 8. Finally, Fig. 9 shows an enlarged view of an area labeled E. It is particularly evident in Fig. 9 that each fin 60 tapers circumferentially on its side facing away from the cooling channel 30. Reference numeral list

[0086] 10 Stator

[0087] 12 pole element

[0088] 14 Double Arrow

[0089] 16 Double Arrow

[0090] 18 Double Arrow

[0091] 20 pole shoe

[0092] 22 pole shoe

[0093] 24 Stator tooth

[0094] 26 windings

[0095] 28 Interior

[0096] 30 Cooling channel

[0097] 32 Arrow

[0098] 34 surface

[0099] 36 surface

[0100] 38 Flow opening

[0101] 39 Flow opening

[0102] 40 Arrow

[0103] 42 second cooling channel

[0104] 44 Blocking element

[0105] 46 Arrow

[0106] 48 Arrow

[0107] 50 supply channel

[0108] 52 Re-injection

[0109] 54 Opening

[0110] 56 Opening

[0111] 58 segments

[0112] 60 Finn

[0113] A distance

[0114] F1 area

[0115] F2 area

[0116] W1 wall

[0117] W2 wall WB1 wall area

[0118] WB2 wall area a winding pitch

Claims

Mercedes-Benz Group AG Patent claims 1. Stator (10) for an axial flux machine, with successive pole elements (12) in the circumferential direction of the stator (10) for forming respective electrical poles of the axial flux machine, wherein the respective pole element (12) has: - two pole shoes (20, 22) opposite each other in the axial direction of the stator (10); and - a stator tooth (24) arranged in the axial direction of the stator (10) between the pole shoes (20, 22), formed from several segments (58) made of a metallic material, around which a winding (26) of the stator (10) is wound; wherein the stator tooth (24) of at least one of the pole elements (12) has in its interior (28) a cooling channel (30) through which a coolant flows for cooling the stator (10), which is completely surrounded along its circumferential direction by the stator tooth (24) of the at least one pole element (12), and wherein the cooling channel (30) has an inlet opening (38) through which the coolant can be introduced into the cooling channel (30) and thereby into the interior (28) of the stator tooth (24), wherein the inlet opening (38) is formed in a first surface (34) of the stator tooth (24) which points outwards or inwards in the radial direction of the stator (10), and wherein the cooling channel (30) has an outlet opening (39),through which the coolant can be discharged from the cooling channel (30) and thus from the interior (28) of the stator tooth (24), wherein the outlet opening (39) is formed in a second surface (36) of the stator tooth (24) which faces away from the first surface (34) in the radial direction of the stator (10) and thus points inwards or inwards towards the outside in the radial direction of the stator (10); thereby, 2024P00686WÖ 23 characterized in that the stator tooth (24) is overmolded with a plastic overmolding (52) which has an opening (54) arranged in overlap with the inlet opening (38) and through which the coolant can flow, and / or an opening (56) arranged in overlap with the outlet opening (39) and through which the coolant can flow, wherein the opening (54, 56) is completely surrounded along its circumferential direction by a wall region (WB1, WB2) of the overmolding (52), and wherein the winding (26) is supported in the axial direction of the stator (10) directly on at least a part of the wall region (WB1, WB2), so that by means of the respective wall region (WB1, WB2) and thus by means of the overmolding (52) the flow openings (38, 39) are kept free of the winding (26).

2. Stator (10) according to claim 1 , characterized in that the cooling channel (30) extends in a straight line from the inlet opening (38) to the outlet opening (39) and vice versa.

3. Stator (10) according to claim 2, characterized in that the cooling channel (30) extends in a straight line parallel to the radial direction of the stator (10) from the inlet opening (38) to the outlet opening (39) and vice versa.

4. Stator (10) according to one of the preceding claims, characterized in that the winding (26) is held at a distance to the stator tooth (24) in the radial direction of the stator (10) by means of the overmolding (52).

5. Stator (10) according to one of the preceding claims, characterized in that the cooling channel (30) is arranged in the middle of the stator tooth (24) when viewed in the axial direction of the stator (10).

6. Stator (10) according to one of the preceding claims, characterized in that the cooling channel (30) has a rectangular flow cross-section through which the coolant can flow.

7. Axial flux machine, with a stator (10) according to one of the preceding claims.

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