Stator for an axial flux machine having an axially oriented coolant outlet, axial flux machine, and traction drive

Abstract

The invention relates to a stator (ST) for an axial flux machine (AFM) of a traction drive for an at least partially electrically powered motor vehicle, the stator comprising: an annular tooth holder (ZH) that has a first end face (ES) pointing in an axial direction of the tooth holder (ZH); an annular cover element (DE) that is arranged on the tooth holder (ZH) and has a second end face (ZS); a plurality of stator teeth (SZ) that are arranged in a cavity (HR) formed by the tooth holder (ZH) and the cover element (DE); a coolant inlet (KME) that is formed in the tooth holder (ZH) or the cover element (DE); and at least one coolant outlet (KMA) that is formed in the first end face (ES) and / or the second end face (ZS) in relation to the coolant inlet (KME).

Description

[0001] Description

[0002] STATOR FOR AN AXIAL FLUX MACHINE WITH AXIALLY ORIENTED COOLANT OUTLET, AXIAL FLUX MACHINE AND TRACTION DRIVE

[0003] The invention relates to a stator for an axial flux machine of a traction drive, wherein the stator has a housing in the form of a toothed holder and a cover element, and at least one coolant outlet aligned in the axial direction of the stator is formed in the housing, so that a coolant can be sprayed via the coolant outlet against a rotor arranged in the axial direction of the stator, spaced from the stator by an air gap. The invention also relates to an axial flux machine with the stator according to the invention. A further subject of the invention is a traction drive for an at least partially electrically powered motor vehicle with the axial flux machine according to the invention.

[0004] Stators for axial flux machines are generally known. These stators typically have a housing in which a plurality of stator teeth are arranged, as is evident, for example, from DE 10 2022 005 069 A1. A cooling channel is inserted between the stator teeth, which runs in a meandering shape in the circumferential direction of the stator. A cooling medium can be passed through the cooling channel to cool the stator teeth.

[0005] It has been shown that it is desirable to direct the coolant directly to the stator teeth and to cool not only the stator but also the rotor, as the latter can also experience elevated temperatures during operation. The increased cooling effect of the stator and also the rotor can increase the performance of the axial flux machine.

[0006] It is an object of the invention to provide a stator for an axial flux machine with which the performance of the axial flux machine can be increased.

[0007] 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 the drawings. Each feature can represent an aspect of the invention, both individually and in combination, unless explicitly stated otherwise in the description.

[0008] In a first aspect of the invention, it is provided that a stator for an axial flux machine of a traction drive for an at least partially electrically driven motor vehicle is provided, comprising an annular tooth holder with a first end face formed in an axial direction of the tooth holder, an annular cover element arranged on the tooth holder with a second end face, and a plurality of stator teeth arranged in a cavity formed by the tooth holder and the cover element, a coolant inlet formed in the tooth holder or the cover element, and at least one coolant outlet formed for the coolant inlet in the first end face and / or the second end face.

[0009] In other words, according to the first aspect of the invention, a stator for an axial flux machine of a traction drive for an at least partially electrically powered motor vehicle is provided. The stator has an annular tooth holder, wherein the tooth holder has a first end face formed in the axial direction of the annular tooth holder. Typically, the tooth holder has a circumferential inner wall adjacent to the first end face and extending in the axial direction of the tooth holder, and a circumferential outer wall arranged at a distance from the inner wall and extending in the axial direction of the stator. Furthermore, it is provided that the stator has an annular cover element that can be arranged directly or indirectly, preferably via a sealing element, on the tooth holder. The cover element has at least one second end face.The tooth holder and the cover element enclose a cavity. In other words, the tooth holder and the cover element can also be referred to as a housing, in particular as a stator housing. A plurality of stator teeth are arranged in the cavity, which are usually spaced apart from one another in the circumferential direction of the tooth holder. A stator tooth generally has a stator core and a stator winding wound or plugged onto the stator core. A coolant inlet is formed in the tooth holder or in the cover element. The coolant inlet can preferably be an inlet opening or an inlet nozzle. At the very least, it is designed and constructed so that a coolant can flow through the coolant inlet into the cavity. The stator teeth can be cooled immediately, i.e. directly, via the coolant flowing into the cavity, whereby an increased cooling effect can be achieved.Furthermore, it is provided that at least one coolant outlet is formed in the first end face and / or in the second end face. Due to the fact that the coolant outlet is formed in the first end face and / or in the second end face, wherein a plane of the first end face and / or a plane of the second end face is aligned at a right angle to the longitudinal direction of the stator, the coolant can escape from the cavity via the coolant outlet in the longitudinal or axial direction of the stator and can preferably be sprayed against a rotor arranged at a distance from the stator via an air gap in the axial direction of the stator. The rotor can thus be directly cooled by the coolant discharged from or sprayed out of the stator. The direct cooling of the stator and rotor can increase the performance of the axial flux machine.

[0010] The coolant is preferably a fluid. The coolant is particularly preferably an oil.

[0011] An advantageous development of the invention lies in the fact that a plurality of stator tooth receptacles are formed in the first end face, spaced apart from one another in the circumferential direction and penetrating the first end face, wherein a first intermediate web is formed between the stator tooth receptacles, and the coolant outlet is formed in at least one first intermediate web. In other words, it is provided that the first end face has openings that are closed at the edges and penetrating the first end face and are arranged at a distance from one another in the circumferential direction of the tooth holder. A stator tooth projects into these openings, at least in sections or partially. This makes it possible to reduce the distance between the stator tooth and the rotor, which is arranged at a distance from the stator tooth via an air gap, which can have a beneficial effect on the performance of the axial flux machine.The coolant outlet is formed in a first intermediate web, which is formed between the openings and preferably extends in the radial direction of the stator between two adjacent openings. A plurality of coolant outlets arranged at a distance from one another in the radial direction of the stator can also be arranged in the first intermediate web. Thus, the coolant outlet has an orientation and position in the radial direction of the stator that allows the coolant to be sprayed directly onto the rotor, and in particular onto magnets of the rotor, whereby an increased cooling effect of the rotor can be achieved. It is preferably provided that at least one coolant outlet is formed exclusively in a first intermediate web. In other words, only a first intermediate web has one or more coolant outlets.This allows the exact location where the coolant is sprayed onto the rotor to achieve maximum cooling effect.

[0012] In a preferred embodiment of the invention, a plurality of stator tooth receptacles are formed in the second end face, spaced apart from one another in the circumferential direction and penetrating the second end face, wherein a second intermediate web is formed between the stator tooth receptacles, and the coolant outlet is formed in at least one second intermediate web. In other words, the second end face of the cover element has openings that are closed at the edge and penetrate the second end face and are arranged at a distance from one another in the circumferential direction of the cover element. A stator tooth projects into each of these openings, at least in sections or partially. This makes it possible to reduce the distance between the stator tooth and the rotor, which is arranged at a distance from the stator tooth via an air gap, which can have a beneficial effect on the performance of the axial flux machine.The coolant outlet is formed in a second intermediate web, which is formed between the openings and preferably extends in the radial direction. A plurality of coolant outlets arranged at a distance from one another in the radial direction of the stator can also be arranged in the second intermediate web. Thus, the coolant outlet has an orientation and position in the radial direction of the stator that allows the coolant to be sprayed directly onto the rotor, and in particular onto the rotor's magnets, thereby achieving an increased cooling effect.

[0013] Preferably, at least one coolant outlet is formed exclusively in a second intermediate web. In other words, only a second intermediate web has one or more coolant outlets. This allows the precise location of the coolant sprayed onto the rotor to achieve maximum cooling.

[0014] According to an advantageous embodiment of the invention, the stator tooth is cast in a media-tight manner using a first casting material on an inner side of the first end face and using a second casting material on an inner side of the second end face, wherein the cavity is formed between the first casting material and the second casting material. The first inner side and the second inner side face one another. In this way, the stator tooth can be fixed in a material-to-material and captive manner in the tooth holder and the cover element. It goes without saying that a corresponding passage must be formed in the first casting material and / or the second casting material in an extension of the coolant outlet so that the coolant can be guided towards the coolant outlet via the casting material.The feedthrough can preferably be formed directly during the formation of the first encapsulation and / or the second encapsulation. However, it is also conceivable for the feedthrough to be formed in the encapsulation material after the encapsulation has hardened, preferably by drilling, milling, or laser cutting.

[0015] The first potting material and the second potting material are preferably identical. This reduces thermally induced stress differences in the potting material.

[0016] However, it is also conceivable that the first potting material is different from the second potting material.

[0017] A preferred embodiment of the invention is that the coolant inlet and the coolant outlet are spaced apart from one another at an angle a of between 90° < a < 270°, preferably between 135° < a < 225°, and particularly preferably between 170° < a < 190°. With an angle a of 170° < a < 190° between the coolant inlet and coolant outlet, it can be ensured that all stator teeth are first cooled by the coolant before the coolant exits.

[0018] In an advantageous embodiment of the invention, the coolant flows in a meandering pattern in the circumferential direction of the stator between the stator teeth. This allows for the most uniform cooling effect possible for the stator teeth.

[0019] According to a preferred embodiment of the invention, the coolant inlet is oriented radially of the stator. Such an arrangement of the coolant inlet allows for a rotor to be arranged at a distance from both the first end face and the second end face. The performance of the axial flux machine can be increased with a so-called double-rotor axial flux machine.

[0020] In a second aspect, the invention relates to an axial flux machine for a traction drive of an at least partially electrically driven motor vehicle, comprising the stator according to the invention and a rotor arranged in the axial direction of the stator via an air gap at a distance from the first end face and / or the second end face, wherein the coolant outlet is arranged in the respective first end face and / or second end face facing the rotor.

[0021] In other words, it is provided that an axial flux machine is provided which has the stator according to the invention, wherein a rotor is arranged in the axial direction of the stator at a distance from the first end face via an air gap and / or a rotor is arranged at a distance from the second end face via an air gap. At least one coolant outlet is arranged in the respective end face from which a rotor is arranged at a distance, so that a coolant flowing into the cavity via the coolant inlet first cools the stator teeth and is sprayed against the rotor via the coolant outlet so that the rotor can also be cooled. By cooling the rotor and stator, the cooling capacity can be increased, which can have a beneficial effect on the performance of the axial flux machine.

[0022] In an advantageous development of the invention, the rotor is provided with magnets, and the coolant outlet is formed in the radial direction of the stator at the level of the magnets. In this way, the magnets can be cooled directly, thus increasing the cooling effect.

[0023] In a third aspect, the invention relates to a traction drive for an at least partially electrically driven motor vehicle with the axial flux machine according to the invention.

[0024] 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. In particular, all features of the stator can equally apply to the axial flux machine and / or the traction drive. This also applies vice versa.

[0025] 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.

[0026] In these show:

[0027] Fig. 1 is a schematic representation of an axial flow machine;

[0028] Fig. 2 is a schematic representation of a coolant flow in a stator of the axial flow machine;

[0029] Fig. 3 shows a section of a three-dimensional view of the stator;

[0030] Fig. 4 shows a flow simulation of the coolant.

[0031] Fig. 1 shows a schematic representation of an axial flux machine AFM for a traction drive of an at least partially electrically powered motor vehicle. The axial flux machine AFM has a stator ST. The stator ST comprises an annular tooth holder ZH, wherein the tooth holder ZH has a first end face ES formed in the axial direction of the annular tooth holder ZH. Furthermore, the tooth holder ZH has a circumferential inner wall IW adjacent to the first end face ES and extending in the axial direction of the tooth holder ZH and a circumferential outer wall AW arranged at a distance from the inner wall IW. Furthermore, the stator ST comprises an annular cover element DE, which is arranged on the tooth holder ZH. The cover element DE has at least one second end face ZS. The tooth holder ZH and the cover element DE enclose a cavity HR.In other words, the tooth holder ZH and the cover element DE can also be referred to as the housing of the stator ST. A plurality of stator teeth SZ are arranged in the cavity HR, which are usually spaced apart from one another in the circumferential direction of the tooth holder ZH. A stator tooth SZ typically has a stator core and a stator winding wound or plugged onto the stator core.

[0032] A coolant inlet KME is formed in the tooth holder ZH, in particular in the circumferential outer wall AW of the tooth holder ZH. The coolant inlet KME can preferably be an inlet opening or an inlet nozzle. At the very least, it is designed and configured so that a coolant KM flows from a reservoir RV through the coolant inlet KME into the cavity HR. The stator teeth SZ can be directly cooled via the coolant KM flowing into the cavity HR, thereby achieving an increased cooling effect of the stator. This can have a beneficial effect on the performance of the axial flux machine AFM.

[0033] Furthermore, it is provided that at least one coolant outlet KMA is formed in the first end face ES and in the second end face ZS. Due to the fact that the coolant outlet KMA is formed in the first end face ES and in the second end face ZS, wherein a plane of the first end face ES and a plane of the second end face ZS are aligned at a right angle to the longitudinal direction LR or longitudinal axis of the stator ST, the coolant KM can escape from the cavity HM via the coolant outlet KMA in the longitudinal direction LR of the stator ST and be sprayed against magnets MA of a rotor RO, which is arranged at a distance from the first end face ES via an air gap, and against magnets MA of a rotor RO, which is arranged at a distance from the second end face ZS via an air gap.

[0034] Thus, both the stator ST and the rotor RO can be cooled directly via the coolant KM, which can increase the performance of the axial flux machine.

[0035] By gravity, the coolant KM, which is sprayed against the rotor RO or against the magnets MA of the rotor RO, flows into a sump SP. From the sump SP, the coolant KM is transported back to the reservoir RV.

[0036] Fig. 2 shows a schematic representation of a coolant flow in the stator ST of the axial flow machine AFM. Starting from the coolant inlet KME, the coolant KM flows in a meandering shape between the stator teeth SZ, which are arranged in the circumferential direction of the stator ST and are spaced from one another, up to the coolant outlet KMA. It is provided that, starting from the coolant inlet KME, a first part of the coolant KM flows in the circumferential direction of the stator ST and a second part of the coolant KM flows counterclockwise of the stator ST. In the area of ​​the coolant outlet KMA, both parts of the coolant KM meet. Furthermore, it can be seen that in the exemplary embodiment shown, the angle α between the coolant inlet KME and the coolant outlet KMA is approximately 170° < α < 190°. This ensures that the coolant KM flowing into the cavity HR via the coolant inlet KME flows around all of the stator teeth SZ and thus cools them.Local hotspots can therefore be reduced or effectively cooled.

[0037] Fig. 3 shows a section of a three-dimensional view of the stator ST. The cover element DE is fastened to the inner wall IW and the outer wall AW via a screw connection SV. A plurality of stator tooth receptacles SZA are formed in the second end face ZS, spaced apart from one another in the circumferential direction and penetrating the second end face ZS. A second intermediate web ZZS is formed between the stator tooth receptacles SZA, with the coolant outlet KMA being formed in at least one second intermediate web ZZS. In other words, it is provided that the cover element DE has openings that are closed at the edge and penetrate the second end face ZS and are arranged at a distance from one another in the circumferential direction of the cover element DE. A stator tooth SZ projects at least partially or partially into each of these openings or stator tooth receptacles SZA.Thus, the distance between the stator tooth SZ and the rotor RO, which is arranged at a distance from the stator tooth SZ via an air gap, can be reduced, which can have a beneficial effect on the performance of the axial flux machine AFM.

[0038] The coolant outlet KMA is formed in at least one second intermediate web ZZS, which is formed between the openings and preferably extends in the radial direction of the stator ST. Thus, the coolant outlet KMA has an orientation and position in the radial direction of the stator ST that allows the coolant KM to be sprayed in the axial direction of the stator ST directly onto the rotor RO, in particular onto the magnets MA of the rotor RO, thereby achieving an increased cooling effect of the rotor RO.

[0039] Fig. 4 shows a flow simulation of the coolant KM from the coolant inlet KME to the coolant outlet KMA. The coolant KM flows via the coolant inlet KME into the cavity HR of the stator ST. Starting from the coolant inlet KME, a first part of the coolant KM flows clockwise around the stator teeth SZ to the coolant outlet KMA. A second part of the coolant KM flows counterclockwise around the stator teeth SZ to the coolant outlet KMA. Both parts of the coolant KM meet at one point and flow through at least one coolant outlet KMA in the axial direction of the stator ST.

Claims

Patent claims 1. Stator (ST) for an axial flux machine (AFM) of a traction drive for an at least partially electrically powered motor vehicle, comprising an annular tooth holder (ZH) with a first end face (ES) formed in an axial direction of the tooth holder (ZH), an annular cover element (DE) arranged on the tooth holder (ZH) with a second end face (ZS), and a plurality of stator teeth (SZ) arranged in a cavity (HR) formed by the tooth holder (ZH) and the cover element (DE), a coolant inlet (KME) formed in the tooth holder (ZH) or the cover element (DE), and at least one coolant outlet (KMA) formed in the first end face (ES) and / or the second end face (ZS) for the coolant inlet (KME).

2. Stator according to claim 1, characterized in that a plurality of stator tooth receptacles (SZA) are formed in the first end face (ES) which are spaced apart from one another in the circumferential direction and penetrate the first end face (ES), wherein a first intermediate web is formed between the stator tooth receptacles (SZA), and the coolant outlet (KMA) is formed in a first intermediate web.

3. Stator according to one of the preceding claims, characterized in that a plurality of stator tooth receptacles (SZA) are formed in the second end face (ZS) which are spaced apart from one another in the circumferential direction and penetrate the second end face (ZS), wherein a second intermediate web (ZZS) is formed between the stator tooth receptacles (SZA), and the coolant outlet (KMA) is formed in a second intermediate web (ZZS).

4. Stator according to one of the preceding claims, characterized in that the stator tooth (SZ) is cast in a media-tight manner via a first casting material to an inner side of the first end face (ES) and via a second casting material to an inner side of the second end face (ZS), wherein the cavity (HR) is formed between the first casting material and the second casting material.

5. Stator according to one of the preceding claims, characterized in that the coolant inlet (KME) and the coolant outlet (KMA) are at an angle a between 90° < a < 270°.

6. Stator according to one of the preceding claims, characterized in that the coolant (KM) runs in a meandering manner in the circumferential direction of the stator (ST) between the stator teeth (SZ).

7. Stator according to one of the preceding claims, characterized in that the coolant inlet (KME) is aligned in the radial direction of the stator (ST).

8. Axial flux machine (AFM) for a traction drive of an at least partially electrically powered motor vehicle, comprising a stator (ST) according to one of the preceding claims, and a rotor (RO) arranged in the axial direction of the stator (ST) via an air gap at a distance from the first end face (ES) and / or the second end face (ZS), wherein the coolant outlet (KMA) is arranged in the respective first end face (ES) and / or second end face (ZS) which faces the rotor (RO).

9. Axial flux machine according to claim 8, characterized in that the rotor (RO) has magnets (MA), and the coolant outlet (KMA) is formed in the radial direction of the stator (RO) at the level of the magnets (MA).

10. Traction drive for an at least partially electrically powered motor vehicle with an axial flux machine (AFM) according to one of claims 8 or 9.

Images