Stator having stator teeth cast in sections, method for producing a stator, axial flux machine and motor vehicle

Abstract

The invention relates to a stator (ST) for an axial flux machine (AFM) of a traction drive (TA) for an at least partially electrically driven motor vehicle (KFZ), having a stator tooth (SZ) which is arranged and / or extends between a tooth holder (ZH) and a cover element (DE) and is connected to the tooth holder (ZH) by means of a first potting material (EVM) and is connected to the cover element (DE) by means of a second potting material (ZVM), wherein a cavity (HR) is formed between the first potting material (EVM) and the second potting material (ZVM) such that a cooling medium (KM) can flow around the stator tooth (SZ) at least in sections between the first potting material (EVM) and the second potting material (ZVM).

Description

[0001] Description

[0002] Stator with sectionally cast stator teeth, method for producing a stator, axial flux machine and motor vehicle

[0003] The invention relates to a stator for an axial flux machine, in which a stator tooth is arranged between a tooth holder and a cover element and is partially encapsulated, and a cooling channel is formed between the encapsulation, so that a cooling medium can flow directly around the stator tooth in sections. The invention also relates to a method for producing the stator according to the invention. Another subject of the invention is an axial flux machine having the stator according to the invention. Furthermore, the invention relates to a motor vehicle having the axial flux machine according to the invention.

[0004] Axial flux machines with stator cooling are generally known. For example, DE 10 2022 205 748 A1 shows a solution in which a plurality of stator teeth are arranged in a tooth holder, and a cooling channel runs in a meandering pattern between the stator teeth. The cooling channel is inserted between the stator teeth as a separate channel. This design can have a reduced cooling effect because the cooling medium does not reach the stator teeth directly.

[0005] It is an object of the invention to provide a stator for an axial flux machine with which the stator teeth can be effectively cooled in a simple and inexpensive manner, whereby the performance of the axial flux machine can be increased.

[0006] This problem is solved by the subject matter of the independent patent claims. Preferred developments of the invention are the subject matter of the dependent patent claims, the following description, and / or the drawings. Each disclosed feature can represent an aspect of the invention, both individually and in combination, unless explicitly stated otherwise in the description.

[0007] In a first aspect, the invention relates to a stator for an axial flux machine of a traction drive for an at least partially electrically driven motor vehicle, comprising a stator tooth arranged and / or extending between a tooth holder and a cover element, which stator tooth is connected to the tooth holder via a first potting material and is connected to the cover element via a second potting material, wherein a cavity is formed between the first potting material and the second potting material, so that a cooling medium can flow around the stator tooth at least in sections between the first potting material and the second potting material.

[0008] In other words, according to the first aspect of the invention, a stator is provided for an axial flux machine. The axial flux machine is preferably part of a traction drive. The traction drive is preferably arranged in an at least partially electrically powered motor vehicle. The stator has stator teeth. Typically, the stator has a plurality of stator teeth. The stator tooth is arranged between a tooth holder and a cover element and / or extends between the tooth holder and the cover element. The tooth holder can preferably also be referred to as a housing in which the stator tooth is arranged, wherein the cover element closes the housing. The stator tooth is connected to the tooth holder via a first potting material. The stator tooth is connected to the cover element via a second potting material. The stator tooth can thus be securely fixed in position in the tooth holder and the cover element.A cavity is formed between the first potting material and the second potting material. A cooling medium can be introduced into this cavity, which can be guided directly past the stator tooth, in particular past a stator winding wound on the stator tooth. This direct cooling allows the stator tooth to be cooled effectively in a simple and cost-effective manner. Furthermore, the direct cooling of the stator tooth can increase the cooling effect, which can have a positive effect on the efficiency and performance of the axial flux machine.

[0009] In an advantageous development of the invention, it is provided that the tooth holder has a first opening into which a first side of the stator tooth at least partially engages, and that an annular space between the first side and the first opening is sealed in a media-tight, in particular fluid-tight, manner by the first potting material. In other words, the tooth holder has a first opening. The first opening is preferably an opening with a closed edge. The opening is particularly preferably continuous. At least a first side of the stator tooth engages at least partially in the first opening. This inevitably results in an annular space between the stator tooth and the first opening. This annular space is closed in a media-tight, in particular fluid-tight, manner by the first potting material, such that the cooling medium cannot escape from the cavity via this annular space.By engaging the first side in the first opening of the tooth holder in sections, a distance between the first side of the stator tooth and a rotor facing the first side can be reduced, which can have a beneficial effect on the performance of the axial flux machine.

[0010] According to a preferred embodiment of the invention, the cover element has a second opening into which a second side of the stator tooth, which is designed at a distance from the first side, engages at least partially, and an annular space between the second side and the second opening is sealed in a media-tight, in particular fluid-tight, manner by the second potting material. In other words, the cover element has a second opening. The second opening is preferably an opening with a closed edge. The second opening is particularly preferably continuous. The first opening and the second opening are aligned and preferably have the same geometric contour and / or design. At least a second side of the stator tooth engages at least partially in the second opening. This inevitably results in an annular space between the stator tooth and the second opening.This annular space is sealed in a media-tight, particularly fluid-tight, manner by the second encapsulating material, so that the cooling medium cannot escape from the cavity via this annular space. By partially engaging the second side in the second opening of the tooth holder, the distance between the second side of the stator tooth and a rotor facing the second side can be reduced, which can have a beneficial effect on the performance of the axial flux machine.

[0011] According to a preferred embodiment of the invention, the first potting material and the second potting material comprise a plastic material. The plastic material is preferably a thermosetting plastic. In particular, the plastic material is an epoxy resin. An epoxy resin has high electrical insulation properties. Furthermore, epoxy resins have high adhesive strength, whereby a good material-to-material connection can be achieved between the stator tooth and the tooth holder, on the one hand, and the cover element, on the other. Furthermore, epoxy resins have low material shrinkage behavior, whereby the media-tightness in the annular space can be ensured. Furthermore, epoxy resins have high heat resistance, which is also advantageous since the stator tooth can experience elevated temperatures during operation of the axial flow machine.Furthermore, epoxy resins have increased chemical and corrosion resistance, which is advantageous when an oil is used as the cooling medium, which flows through the cavity and is thus in direct contact with the first potting material and the second potting material.

[0012] It is conceivable that the first potting material and the second potting material are different from one another. In other words, the first potting material can preferably be an epoxy resin, while the second potting material is a different epoxy resin from the first potting material. The use of two different potting materials can be useful if different materials are used for the cover element and the tooth holder. Thus, the potting material can be adapted to the carrier materials, i.e., the tooth holder or the cover element, to ensure cohesive bonding and / or media tightness.

[0013] Alternatively, a preferred embodiment of the invention provides for the first potting material and the second potting material to be identical. This allows the manufacturing costs of the stator to be reduced, since only one type of potting material is kept in stock and injected. The use of a uniform potting material can also have a beneficial effect on the setup and cleaning times of the potting device when only one potting device is available. Thus, the cycle time for manufacturing the stator can be reduced, which can have a beneficial effect on the manufacturing costs of the stator.

[0014] In an advantageous embodiment of the invention, a stator winding is wound on the stator tooth, and the stator winding is arranged between the first potting material and the second potting material. It is particularly advantageous for the stator winding to be free of the first potting material and / or the second potting material. In this way, heat from the stator winding can be prevented from accumulating in the first potting material and / or the second potting material. At the same time, it can be achieved that the cooling medium can flow to the entire stator winding of the stator. This can increase the cooling capacity, which can have a beneficial effect on the efficiency or performance of the axial flux machine. According to a preferred development of the invention, it is provided that the cover element can be or is fixed to the tooth holder. The fixation is preferably a screw and / or rivet connection.However, it is also conceivable for the cover element to be attached to the tooth holder via a material-to-material connection, preferably an adhesive or welded joint. This allows the tooth holder and the cover element to be easily connected to each other.

[0015] Preferably, the cover element is fixed directly to the tooth holder. With direct fixation, a sealing element can be arranged at least partially in the connection area. The sealing element can increase the media tightness in the joint area between the tooth holder and the cover element.

[0016] In a preferred embodiment of the invention, the tooth holder is designed in the shape of a circular ring and has a U-shaped configuration in a longitudinal section through the tooth holder. The U-shaped configuration is therefore related to a section through the circular ring. In other words, the tooth holder has an inner peripheral wall, an outer peripheral wall arranged at a distance from the inner peripheral wall, and a base element formed between the inner peripheral wall and the outer peripheral surface. The first opening for receiving the first side of the stator tooth is formed in the base element. The cover element can be easily arranged and fixed on an outer side of the inner peripheral wall and the outer peripheral wall facing away from the base element.

[0017] It is particularly preferred if the inner peripheral wall and the outer peripheral wall have, at least in sections, the same height in the longitudinal direction of the stator and / or tooth holder, so that the cover element can be designed as a flat circular disk and arranged on the outer side of the inner peripheral wall and the outer side of the outer peripheral wall. The cover element can thus be manufactured inexpensively, which can have a beneficial effect on the manufacturing costs of the stator.

[0018] In this context, a preferred embodiment of the invention is that a first potting opening for introducing the first potting material and / or a second potting opening for introducing the second potting material is formed in an inner peripheral wall and / or in an outer peripheral wall of the U-shaped tooth holder. The first potting opening extends from the outside of the inner peripheral wall and / or the outer peripheral wall, through the corresponding peripheral wall up to and / or to a height of the first potting material to be introduced. The second potting opening extends from an outer wall of the base element, with the outer wall facing away from the outside, through the inner peripheral wall and / or the outer peripheral wall up to and / or to a height of the second potting material to be introduced. In this way, the potting material can be introduced easily from the outside.

[0019] According to an advantageous embodiment of the invention, it is provided that the stator has a plurality of stator teeth spaced apart from one another in the circumferential direction of the annular tooth holder.

[0020] In a second aspect, the invention relates to a method for producing the stator according to the invention, comprising the steps:

[0021] - Providing a tooth holder,

[0022] - Arranging a stator tooth in the tooth holder,

[0023] - Placing a cover element on the tooth holder so that the stator tooth is arranged and / or extends between the tooth holder and the cover element,

[0024] - Casting the stator tooth to the tooth holder with a first casting material, and the stator tooth and the cover element with a second casting material, so that a cavity is formed between the first casting material and the second casting material.

[0025] In other words, according to the second aspect of the invention, a tooth holder is provided for producing the stator. A stator tooth is first arranged in the tooth holder. A cover element is arranged on the tooth holder such that the stator tooth is arranged between the cover element and the tooth holder and / or is at least partially enclosed by the tooth holder and the cover element. Furthermore, it is provided that the stator tooth is cast onto the tooth holder with a first casting material and the stator tooth is cast onto the cover element with a second casting material such that a cavity is formed between the first casting material and the second casting material. A cooling medium can flow through the cavity and directly around the stator tooth, at least in sections, such that it can be effectively cooled.In an advantageous development of the invention, it is provided that the potting with the first potting material takes place at a time offset from the potting with the second potting material. It is preferably provided that first the stator tooth is potted onto the tooth holder with the first potting material and, after the first potting material has at least partially cured, the stator tooth is potted onto the cover element with the second potting material. In this way, the annular tooth holder can preferably be arranged in a direction perpendicular to its longitudinal direction in order to introduce the first potting material. The first potting material can thus be advantageously distributed in order to enable a material-to-material and / or media-tight connection of the stator tooth to the tooth holder in a simple manner.Subsequently, it is preferably provided that the stator and / or the tooth holder are pivoted by 180° between the first potting material and the second potting material. After the pivoting, the second potting material can be introduced and distributed accordingly.

[0026] According to a preferred embodiment of the invention, the first potting material is injected before the cover element is arranged on the tooth holder, and the second potting material is injected after the cover element is arranged on the tooth holder. In this way, the stator tooth can preferably be pressed more easily onto the tooth holder, in order to then subsequently bond it to the tooth holder via the second potting material and / or to pot the annular space between the first side of the stator tooth and the first opening in the tooth holder. Furthermore, a visual inspection of the first potting material can be carried out easily.

[0027] An advantageous development of the invention is that the stator tooth is pressed against the tooth holder during the introduction of the first potting material, and / or the stator tooth is pressed against the cover element during the introduction of the second potting material. Pressing the stator tooth against the cover element and / or the tooth holder can be advantageous for the secure and integral connection of the stator tooth to the cover element or the tooth holder.

[0028] In a third aspect, the invention relates to an axial flux machine with the stator according to the invention. The axial flux machine is preferably used in a traction drive of an at least partially electrically powered motor vehicle.

[0029] In a fourth aspect, the invention relates to a motor vehicle with the axial flux machine according to the invention, wherein the motor vehicle is at least partially, preferably completely, electrically powered. The axial flux machine is particularly preferably a component of a traction drive.

[0030] It should be noted that all features described above and below with respect to one aspect of the present invention equally apply to any other aspect of the present invention. Specifically, all features of the stator can equally apply to the method for manufacturing the stator, to the axial flux machine, and / or to the motor vehicle. This also applies vice versa.

[0031] Further features and advantages of the present invention emerge from the dependent claims and the following exemplary embodiments. The exemplary embodiments are not restrictive, but rather to be understood as examples. They are intended to enable the skilled person to implement the invention. The applicant reserves the right to make individual and / or several of the features disclosed in the exemplary embodiments the subject of patent claims or to incorporate such features into existing patent claims. The exemplary embodiments are explained in more detail with reference to drawings.

[0032] In these show:

[0033] Fig. 1 is a schematic representation of an axial flow machine,

[0034] Fig. 2 is a schematic representation of a coolant flow through a stator, Fig. 3 is a section through the view of the stator,

[0035] Fig. 4 a longitudinal section through the stator with a tooth holder,

[0036] Fig. 5 is a longitudinal section through the stator, with a cover element arranged on the tooth holder,

[0037] Fig. 6 a section through a 3D view of the stator,

[0038] Fig. 7 shows a method for producing the stator, Fig. 8 shows a motor vehicle. Fig. 1 shows a schematic representation of an axial flux machine AFM. The axial flux machine AFM has a stator ST. A rotor RO is arranged at a distance from a respective distal end DE of the stator ST and has at least one magnet MA on a side facing the stator ST. A cooling medium KM for cooling stator teeth SZ is introduced into the stator ST via a coolant inlet KME. The cooling medium KM is discharged from the stator ST via a coolant outlet KMA and fed to a coolant circuit for further cooling of the stator ST.

[0039] Fig. 2 shows a schematic representation of a coolant flow of the coolant KM through the stator ST. The stator ST is circular and has a plurality of stator teeth SZ that are arranged at a distance from one another in the circumferential direction of the stator ST. The stator teeth SZ preferably have a trapezoidal shape. Starting from the coolant inlet KME, a first part of the coolant KM flows clockwise through the stator ST in a meandering pattern between the stator teeth SZ to the coolant outlet KMA. A second part of the coolant KM flows counterclockwise in a meandering pattern between the stator teeth SZ to the coolant outlet KMA. By splitting the coolant flow in two directions, a more even cooling of the stator teeth SZ can be achieved, which can be advantageous for the performance of the axial flow machine.

[0040] Fig. 3 shows a section through a view of the stator ST. The stator ST has a tooth holder ZH in the shape of a circular ring, which has a U-shaped configuration in a longitudinal section through the tooth holder ZH. The U-shaped configuration is therefore related to a section through the circular ring. In other words, the tooth holder ZH has an inner circumferential wall IUW, an outer circumferential wall AUW arranged at a distance from the inner circumferential wall IUW and a base element BE formed between the inner circumferential wall IUW and the outer circumferential surface AUW. A first opening EO is arranged in the base element BE. The first opening EO is preferably designed as an opening with a closed edge. It is designed to receive a first side ES of the stator tooth SZ. The stator tooth SZ has a stator winding SW on an outer side of the stator tooth SZ.

[0041] A cover element DE can be arranged in a simple manner on an outer side AS of the inner peripheral wall IUW and the outer peripheral wall AUW facing away from the base element BE, so that the stator tooth SZ extends between the cover element DE and the base element BE.

[0042] Fig. 4 shows a longitudinal section through the stator ST during an injection molding process for the integral connection of the stator tooth SZ to the tooth holder ZH. The tooth holder ZH is clamped in the axial direction of the stator ST between two pressure plates DP, so that the stator tooth SZ is pressed against the tooth holder ZH, in particular against an inner side of the base element BE, at least in sections. The stator tooth SZ is integrally connected to the tooth holder ZH via a first potting material EVM. In addition, an annular space between the first side ES of the stator tooth ST and the first opening EO is sealed in a media-tight, in particular fluid-tight, manner via the first potting material EVM.

[0043] The first potting material EVM is injected through a first potting opening EVO formed in the inner circumferential wall IUW of the U-shaped tooth holder ZH. The first potting opening EVO extends from the outer side AS of the inner circumferential wall IUW in the axial direction of the tooth holder ZH through the inner circumferential wall IUW up to and / or into a height of the first potting material EVM to be introduced.

[0044] Fig. 5 shows a longitudinal section through the stator ST during an injection process for the material connection of the stator tooth SZ to the cover element DE.

[0045] After the first potting material EVM has been introduced into the tooth holder ZH for the integral connection of the stator tooth SZ to the tooth holder ZH and for filling the annular space between the stator tooth SZ and the first opening OE and has at least partially cured, the cover element DE is arranged on the outer side AS or in a fold of the outer side AS of the inner circumferential wall IUW and the outer circumferential wall AUW. A second opening ZO is formed in the cover element DE, into which a second side ZS of the stator tooth SZ, which faces away from the first side ES of the stator tooth SZ, can at least partially engage.

[0046] Compared to the stator ST shown in Fig. 4, the stator ST shown in Fig. 5 is arranged between the two pressure plates DP, rotated by 180°. The second potting material ZVM is injected through a second potting opening ZVO, which extends from an outer wall AW of the base element BE, with the outer wall AW facing away from the outer side AS, through the inner peripheral wall lUW up to and / or into a height of the second potting material ZVM to be introduced.

[0047] A cavity HZ is formed between the first potting material EVM and the second potting material ZVO, so that the cooling medium KM can flow into this cavity HR and cool the stator tooth SZ and / or the stator winding SW wound on the stator tooth SZ.

[0048] Fig. 6 shows a section through the stator ST in a 3D view, schematically showing the first potting material EVM, the second potting material ZVM and the cavity HR formed between the first potting material EVM and the second potting material ZVM.

[0049] Fig. 7 shows a method for manufacturing the stator ST.

[0050] In a first step 100, a tooth holder ZH is provided. The tooth holder ZH is configured and / or designed to receive a stator tooth SZ.

[0051] In a second step 110, the stator tooth SZ is arranged in the tooth holder ZH. Preferably, a first side ES of the stator tooth SZ engages in a first opening EO of the tooth holder ZH, which is preferably arranged and formed in a base element BE of the tooth holder BE.

[0052] In a third step 120, the stator tooth SZ is materially connected to the tooth holder ZH via a first potting material EVM and, if present, an annular space between the first side ES of the stator tooth SZ and the first opening EO is closed in a media-tight, in particular fluid-tight, manner.

[0053] In a fourth step 130, a cover element DE is arranged on the tooth holder ZH, so that the stator tooth SZ extends between the tooth holder ZH, in particular between the base element BE and the cover element DE. The cover element DE preferably has a second opening ZO, into which a second side ZS of the stator tooth SZ engages.

[0054] In a fifth step 140, the stator tooth SZ is bonded to the cover element DE via a second potting material ZVM, and, if present, an annular space between the second side ZS of the stator tooth SZ and the second opening EO of the cover element DE is closed in a media-tight, in particular fluid-tight, manner. The third step 130 and the fifth step 140 are carried out such that a cavity HR is formed between the first potting material EVM and the second potting material ZVM. A cooling medium KM can be introduced into the cavity HR, which can be guided directly to the stator tooth SZ and / or the stator winding SW wound on the stator tooth SZ in order to cool the stator tooth SZ and / or the stator winding SW.

[0055] Fig. 8 shows a motor vehicle with the axial flux machine AFM in a traction drive TA.

Claims

Patent claims 1. Stator (ST) for an axial flux machine (AFM) of a traction drive (TA) for an at least partially electrically powered motor vehicle (KFZ), comprising a stator tooth (SZ) arranged and / or extending between a tooth holder (ZH) and a cover element (DE), which stator tooth is connected to the tooth holder (ZH) via a first potting material (EVM) and is connected to the cover element (DE) via a second potting material (ZVM), wherein a cavity (HR) is formed between the first potting material (EVM) and the second potting material (ZVM), such that a cooling medium (KM) can flow around the stator tooth (SZ) at least in sections between the first potting material (EVM) and the second potting material (ZVM).

2. Stator according to claim 1, characterized in that the tooth holder (ZH) has a first opening (EO) into which a first side (ES) of the stator tooth (SZ) engages at least partially, and an annular space between the first side (ES) and the first opening (EO) is sealed in a media-tight manner by the first potting material (EVM).

3. Stator according to one of the preceding claims, characterized in that the cover element (DE) has a second opening (ZO) into which a second side (ZS) of the stator tooth (SZ), which is designed at a distance from the first side (ES), engages at least partially, and an annular space between the second side (ZS) and the second opening (ZO) is sealed in a media-tight manner by the second potting material (ZVM).

4. Stator according to one of the preceding claims, characterized in that the first potting material (EVM) and the second potting material (ZVM) are a plastic material.

5. Stator according to one of the preceding claims, characterized in that the first potting material (EVM) and the second potting material (ZVM) are the same.

6. Stator according to one of the preceding claims, characterized in that a stator winding (SW) is wound on the stator tooth (SZ), and the stator winding (SW) is arranged between the first potting material (EVM) and the second potting material (ZVM).

7. Stator according to one of the preceding claims, characterized in that the tooth holder (ZH) is circular in shape and has a U-shaped configuration in a longitudinal section through the tooth holder (ZH).

8. Stator according to one of the preceding claims, characterized in that in an inner peripheral wall (IUW) and / or in an outer peripheral wall (AUW) of the U-shaped tooth holder (ZH) a first potting opening (EVO) for introducing the first potting material (EVM) and / or a second potting opening (ZVO) for introducing the second potting material (ZVM) is formed.

9. A method for producing a stator (ST) according to any one of the preceding claims, comprising the steps: - Providing a tooth holder (ZH), - arranging a stator tooth (SZ) in the tooth holder (ZH), - placing a cover element (DE) on the tooth holder (ZH) so that the stator tooth (SZ) is arranged and / or extends between the tooth holder (ZH) and the cover element (DE), - Casting the stator tooth (SZ) onto the tooth holder (ZH) with a first casting material (EVM), and the stator tooth (SZ) and the cover element (DE) with a second casting material (ZVM), so that a cavity (HR) is formed between the first casting material (EVM) and the second casting material (ZVM).

10. The method according to claim 9, characterized in that the casting with the first casting material (EVM) is carried out with a time delay to the casting with the second casting material (ZVM).

11. Method according to claim 9 or 10, characterized in that the first potting material (EVM) is injected before the arrangement of the cover element (DE) on the tooth holder (ZH), and the second potting material (ZVM) is injected after the arrangement of the cover element (DE) on the tooth holder (ZH).

12. Method according to one of claims 9 to 11, characterized in that between the casting with the first casting material (EVM) and the second casting material (ZVM), the stator (ST) is pivoted by 180°.

13. Method according to one of claims 9 to 12, characterized in that during the introduction of the first potting material (EVM) the stator tooth (SZ) is pressed against the tooth holder (ZH), and / or during the introduction of the second potting material (ZVM) the stator tooth (SZ) is pressed against the cover element (DE).

14. Axial flux machine (AFM) with a stator (ST) according to one of claims 1 to 8.

15. Motor vehicle (KFZ) with an axial flux machine (AFM) according to claim 14.

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