Method for producing a stator of an axial flux machine and stator produced by said method

Abstract

The invention relates to a simplified method for producing at least a part of a stator of an axial flux machine by providing a first joining section (21) made of a first material on a first stator pole (11) of the stator and providing a second joining section (22) made of a second material on a second stator pole (12) of the stator. In this case, a first joining section (21) of the first stator pole (11) and a second joining section (22) of the second stator pole (12) overlap in an overlap region (5) in the circumferential direction of the stator and are joined, the second joining section (22) being further outward than the first joining section (21) with respect to the center of the stator. The second material is at least mostly permeable to the predetermined laser wavelength, but the first material is impermeable to the predetermined laser wavelength. The first joining section (21) is welded to the second joining section (22) by irradiating the overlap region (5) with a laser beam (9) of a predetermined laser wavelength. The invention also relates to a stator manufactured by using the above method.

Description

Field of the Invention

[0001] The present invention relates to a method for manufacturing at least a part of a stator for an axial flux machine. Furthermore, the present invention relates to a stator for an axial flux machine and an electric axial flux machine itself. Background Art

[0002] For example, an axial flux machine can be implemented as a disk rotor motor, in which the rotor and the stator are configured in a disk shape. The magnetic field is parallel to the axis of rotation.

[0003] The stator poles of the axial flux machine are arranged adjacent to each other in the circumferential direction. Before installing the windings, the individual teeth are usually insulated. This insulation is achieved, for example, by coating the stator teeth with a plastic material.

[0004] Regarding the manufacture of electric machines, certain techniques, such as laser welding, overmolding, casting, and injection molding, and other methods are well known. In this regard, reference is made to JP 2011193564 and WO 2011 / 037 087. It is also specifically stated therein that, for joining together, the poles can be laser welded and / or injection molded.

[0005] In documents US2008 / 0315699 and DE 10 2016 213 110, it is mentioned that plastic components are connected to each other by laser welding and fixed in / on the electric machine.

[0006] Document JP 2006 325 345 describes a rotor in which plastic components are connected to each other by laser welding. However, the purpose of doing so is to create a stable connection with a dielectric seal between the components of the rotor. Summary of the Invention

[0007] The object of the present invention is to simplify the manufacture of the stator of an axial flux machine.

[0008] According to the present invention, this object is achieved by the method and the stator according to the independent claims. Advantageous refinements of the present invention result from the dependent claims.

[0009] Thus, according to the present invention, there is provided a method for manufacturing at least a part of a stator for an axial flux machine. The claimed method mainly relates to the joining of two stator poles and thus only relates to a part of the stator of the axial flux machine. Of course, more than two or all of the stator poles of the stator can also be joined together in this way.

[0010] First, a first joint section made of a first material is attached to a first stator pole of the stator. Similarly, a second joint section made of a second material is attached to a second stator pole of the stator. The joint sections are used to join the stator poles together. Generally, a stator pole not only has one joint section, but usually has four joint sections, two for each joint section to connect to adjacent stator poles.

[0011] In this case, in the joined state of the first stator pole and the second stator pole, the first joint section and the second joint section overlap in an overlapping region along the circumferential direction of the stator. In the (axial) plan view of the overlapping region, this means that the two joint sections are one above the other.

[0012] The second joint section is located more outward relative to the center of the stator than the first joint section. In particular, the second joint section should be freely accessible from the outside, while the first joint section can be hidden by the second joint section. Therefore, the distance from the center of the stator to the second joint section is greater than the distance from the center to the first joint section.

[0013] The second material is at least mostly transmissive to a pre-given laser wavelength, while the first material is non-transmissive to the pre-given laser wavelength. Therefore, two different materials are used for the joint sections. Preferably, the second material of the outer second joint section is transparent and can also be referred to as a transmitter, while the material of the inner first joint section is opaque and can therefore also be referred to as an absorber.

[0014] Finally, the overlapping region is irradiated with a laser beam of a pre-given laser wavelength, whereby the first joint section is welded to the second joint section. Since the preferably transparent second joint section is located outside, the laser beam can reach the first joint section and be absorbed there. This means that most of the energy, at least most of the energy, is absorbed in the inner first joint section, while no or only very little laser beam energy is absorbed in the outer joint section. In this case, the energy of the laser beam is high enough to melt the first joint section and thus weld it to the second joint section. The second joint section is also optionally melted at least in the surface region.

[0015] In an advantageous design of the method according to the invention, the joint sections are welded in such a way that the overlapping region seals the cavity or cooling chamber between the two stator poles in a media-tight manner. The pole teeth of the stator poles are usually surrounded by corresponding windings. There is usually a small gap between the windings of two adjacent stator poles, which can be used for the flow of coolant. This results in a cavity in which the cooling medium can flow. This cavity can be sealed axially by the two joint sections. For this purpose, it is usually necessary to weld the two joint sections along their entire radial extension scale (roughly corresponding to the radial extension scale of the stator poles). This of course applies to the two axial end faces.

[0016] In another advantageous embodiment, the stator is provided with a central axis extending parallel to the stator poles or the corresponding main magnetic flux of the axial flux machine. This central axis corresponds to the named axis of the axial flux machine. Then, the second joining section is arranged axially or radially outside the first joining section with respect to the central axis. This means that in the case of an axial laser beam, the second (transparent) joining section is first penetrated by the laser beam and then reaches the opaque joining section inside the axis and is absorbed there.

[0017] In another embodiment, the stator poles are each provided with windings before welding. Generally, the teeth or laminated cores of the stator poles can be completely molded with the corresponding material or insulating material. Then, the corresponding windings of the stator poles can be slid or wound on this insulating material. If individual stator poles are provided with their windings, they can be plugged into each other and finally welded.

[0018] According to an advantageous design of a method according to the invention, two stator poles are plugged into each other before welding, and the two joining sections are snapped together and / or form a form-fit with each other. The advantage of snapping together is that the stator poles are already held together before welding. Snapping together can be achieved by a (detachable) snap connection. For example, the stator poles can be plugged into each other in the circumferential direction so that they snap together. However, other types of form-fits can also be selected between the stator poles. For example, adjacent stator poles can be plugged into each other one by one, for example, in the radial direction, according to the groove spring principle. In this case, for example, the groove represents one joining section and the spring represents the other joining section. If the groove is transparent and the spring is opaque, laser welding can also be carried out here.

[0019] According to the invention, the above object is also achieved by a stator for an axial flux machine, comprising a first joining section made of a first material on a first stator pole of the stator, a second joining section made of a second material on a second stator pole of the stator, wherein, in the joined state of the first stator pole and the second stator pole, the first joining section overlaps with the second joining section in an overlapping region in the circumferential direction of the stator, wherein the second joining section is more outward with respect to the center of the stator than the first joining section, wherein the second material is at least mostly transmissive for a pre-given laser wavelength, the first material is non-transmissive for the pre-given laser wavelength, and the first joining section is welded to the second joining section.

[0020] The variant possibilities and advantages described above in connection with the method according to the invention also apply to the stator according to the invention. The corresponding method features can be regarded as functional features of the stator.

[0021] In one embodiment, the first stator poles are provided with engagement sections of a first engagement section type on the axially outer side on the side facing the second stator poles, and also with engagement sections of the first engagement section type on the axially outer side on the opposite side. Further, the second stator poles are provided with engagement sections of a second engagement section type on the axially outer side on the side facing the first stator poles, and also with engagement sections of the second engagement section type on the axially outer side on the opposite side. This means that, in a radial plan view, the first stator poles each have a first engagement section at their four corners, and the laser beam is not transmissible there. In contrast, the second stator poles have outer engagement sections made of a laser-transparent or transmissible material at their four corners, which can be seen in the radial plan view. This can be simply achieved by two different injection moldings of the stator poles, where the second stator poles are, for example, fully injection-molded with a laser-transmissible plastic such that the "outer overlap" (outer engagement section) is always injection-molded accordingly on both sides and two overlapping areas in the circumferential direction (all four overlapping areas of one pole), and the first stator poles are, for example, fully injection-molded with a laser-non-transmissible plastic such that the "inner overlap" (inner engagement section) is always injection-molded accordingly on two axial sides and two overlapping areas in the circumferential direction (all four overlapping areas of one pole). Then, these so-different stator poles must be arranged alternately in the circumferential direction such that the "outer overlap" (transparent) of the second stator poles can always overlap and be welded with the opaque "inner overlap" of the first stator poles. Thus, in this example, there are two different types of stator poles.

[0022] In an alternative embodiment, the first stator poles are provided with engagement sections of a first engagement section type axially outside on the side facing the second stator poles and with engagement sections of a second engagement section type axially outside on the opposite side, and the second stator poles are provided with engagement sections of a second engagement section type axially outside on the side facing the first stator poles and with engagement sections of a first engagement section type axially outside on the opposite side. This in turn means that the two stator poles can have the same construction. For example, in a radial plan view, it has an external overlap on one side and an internal overlap on the other side. Thus, it is possible to produce only one type of pole which has an external overlap with the transparent material on one side (axial and / or circumferential direction) and a corresponding internal overlap with the opaque material on the other side. In this case, the pole itself will be "asymmetric" since the two overlap regions always have an external overlap and the two overlap regions have an internal overlap. Geometrically correct is that the pole is axisymmetric with respect to the axial center plane, axisymmetric with respect to the center plane in the circumferential direction, or symmetric with respect to the center point of the pole. When connecting the stator poles to the stator ring, it is not necessary to alternately consider the type of pole, but at most the spatial orientation such that the external and internal overlaps are always together. However, such stator poles must be injection-molded with two different materials, which can be done in one step (by two or more syringes) or successively in several steps.

[0023] In another embodiment, the first stator poles are provided with a first engagement section and an engagement section of a second engagement section type axially opposite on the side facing the second stator poles, and on the opposite side, axially outside and circumferentially opposite the first engagement section, with an engagement section of a second engagement section type and an engagement section of a first engagement section type axially opposite the engagement section of the second engagement section type, and the second stator poles are provided with a second engagement section and an engagement section of a first engagement section type axially opposite on the side facing the first stator poles, and on the opposite side, axially outside and circumferentially opposite the second engagement section, with an engagement section of a first engagement section type and an engagement section of a second engagement section type axially opposite the engagement section of the first engagement section type. In a radial plan view, this means that the internal overlap (type of the first engagement section) and the external overlap (type of the second engagement section) alternate around the stator pole. As in the previous embodiment, although external and internal overlaps are provided on the stator poles, a single type of stator pole is sufficient for the production of the stator ring. In a radial plan view, the pole will be symmetric with respect to the center point of the pole.

[0024] In an advantageous design of the stator according to the invention, the joining section is molded onto the pole shoe and / or the pole teeth of the respective stator pole. If required, the respective stator pole can be completely injection-molded with the respective (insulating) material. Thus, the material fulfills multiple functions, namely insulation and mechanical fixation of the stator pole.

[0025] In another embodiment, one of the two joining sections has a projection in the overlapping region, and the other of the two joining sections has a cavity, wherein, in the joined state of the first stator pole and the second stator pole, the projection projects into the cavity. In particular, this enables the two stator poles to be snapped together. Specifically, this can be achieved by having such a projection and such a cavity in the overlapping region on each of the two axial sides of the stator pole, and in the snapped state of the stator pole, the respective projection projects into the respective cavity. For example, the projection and the cavity can be circular, such that the stator poles can be releasably snapped together. However, other geometries of the projection and the cavity can also be used in principle. The projection and the cavity do not have to extend over the entire radial length of the stator pole. If required, one or more short radial portions are sufficient, where the respective projection and cavity project into each other.

[0026] In another advantageous design of the stator according to the invention, the joining sections welded together along the entire radial extension scale of the stator pole in the overlapping region seal the cooling circuit (inside the stator pole). Thus, for example, when the stator poles are connected together, the space generated between them or between their windings can be used for coolant flow. The respective cooling circuit can pass through all the stator poles of the stator, or can also pass through only a part of the stator. To seal the cooling circuit, the stator poles can be welded together along their entire radial extension scale (on both axial sides). Then, corresponding welding must also be performed on the radial end faces of the stator poles.

[0027] The joining sections can be positioned relative to each other such that, in the joined state of the first stator pole and the second stator pole, they are pressed against each other. This prestress can be particularly used to ensure that the joining sections are firmly positioned relative to each other during the welding process. For this purpose, it is advantageous, for example, if the outer joining section (outer overlap) has an undercut, such that it has an elastic design. Then, the inner joining section (inner overlap) can be pressed into this undercut, such that the two joining sections are pressed against each other in the joined state.

[0028] Furthermore, a tolerance gap can be formed between the first joining section and the second joining section in the circumferential direction. Thus, for example, the possibility that manufacturing tolerances prevent the joining sections from being precisely snapped together can be excluded. Thus, a stable, process-reliable (especially with respect to tolerances) and media-tight connection can be provided between the poles or the pole shoes.

[0029] In another embodiment, two stator poles each have a winding, and the engagement sections are arranged axially outside the windings respectively. Optionally, the engagement sections can be arranged precisely between the stator poles. Also optionally, the engagement sections can axially protrude beyond the stator poles. For example, the overlapping area can advantageously be arranged outside the coil area or winding area. In this case, it can also slightly protrude outside the pole shoes and poles (optionally symmetric between external overlap and internal overlap), such that the connection points are also exactly between the two poles. However, optionally, this can also be asymmetric, such that only the external overlap protrudes outside the poles, while the internal overlap remains arranged in the pole area. Then the connection points are still in the pole area, rather than between the two poles (in the middle).

[0030] According to the present invention, the above object is also achieved by an axial flux electric machine having a stator of the above type.

[0031] Other advantages, features and details of the present invention will become apparent from the following description of the preferred embodiments and the drawings. Without departing from the scope of the present invention, the above-mentioned features and combinations of features mentioned in the description, as well as the features and combinations of features mentioned in the drawing description and / or shown separately in the drawings, can be used not only in the respective combinations, but also in other combinations or alone. Description of the Drawings

[0032] Figure 1 A part of the stator of an axial flux machine is shown;

[0033] Figure 2 Shows Figure 1 A cross-sectional view of the stator of

[0034] Figure 3 Shows Figure 2 An enlarged detail of

[0035] Figure 4 Shows Figure 3 An enlarged cross-section of

[0036] The embodiments described in more detail below represent the preferred embodiments of the present invention. Detailed Description of the Invention

[0037] Figure 1 A part of the stator of an axial flux machine is shown in a perspective view. The stator is formed by an annular arrangement of a plurality of stator poles 1 joined to each other. The annular stator has a central axis 2, which not only forms the rotational axis of one or more rotors (not shown), but also indicates the main magnetic flux direction. The following descriptions of the radial direction, axial direction and circumferential direction (as well as the above explanations) are always with respect to this central axis 2.

[0038] Each stator pole 1 has a pole shoe 3 on its axial side. In this example, the pole shoe 3 is injection-molded with a plastic 4, which can have a holding and / or insulating function. Each individual stator pole 1 is initially manufactured separately and injection-molded with the plastic 4. Then the individual stator poles 1 are joined together to form Figure 1 the annular stator shown. When the stator poles 1 are joined together, the plastic injection moldings 4 of two stator poles 1 meet each other and form an overlapping region 5 that extends substantially radially.

[0039] Each stator pole 1 has a corresponding winding 6, which is arranged between the corresponding pole shoes 3 that are axially spaced apart on the corresponding pole teeth and are not visible here.

[0040] Figure 2 A cross-section through a plurality of stator poles 1 parallel to the central axis 2 is shown. For each stator pole 1, this cross-section shows the arrangement of the corresponding pole teeth 7 between the pole shoes 3. Each pole tooth 7 is surrounded by a corresponding winding 6. The windings 6 of two adjacent stator poles 1 meet each other and a part of the overlapping region 5 is also located in the partial region of the cross-section, which is denoted by III. This partial region III is Figure 3 shown in an enlarged form. It can be seen from this enlarged view that the pole teeth 7 can have an initial injection molding, also referred to here as (plastic) injection molding 4. The corresponding winding 6 is applied to the initial injection molding in the region of the pole teeth 7. A cooling chamber 8 is formed between the windings 6 of two adjacent stator poles 1, which can be filled with a cooling medium.

[0041] In Figure 3 the example of, the stator pole shown in the lower figure can be designated as the first stator pole 11, and the pole shown in the upper figure can be designated as the second stator pole 12. The first stator pole 11 has first engagement sections 21 on both axial sides in each case. The first engagement sections 21 project beyond the pole shoe 3 in the circumferential direction. The first engagement sections 21 are preferably integrally formed with the injection molding 41 of the pole teeth 7 of the first stator pole 11. In particular, the injection molding 41 and the first engagement sections 21 are made of the same (plastic) material.

[0042] In the same way, the second stator pole 12 has second engagement sections 22 on both axial sides. The second engagement sections 22 also project beyond the pole shoe 3 of the second stator pole 12 in the circumferential direction.

[0043] In Figure 3 the joined state of the first stator pole 11 and the second stator pole 12 shown, the first engagement sections 21 and the second engagement sections 22 overlap in the overlapping region 5. The second engagement sections 22 are located on both sides axially outside the corresponding first engagement sections 21. Therefore, the first engagement sections 21 can be referred to as internal overlap, and the second engagement sections 22 can be referred to as external overlap.

[0044] The first joining section 21 and the second joining section 22 (i.e., internal overlap and external overlap) are joined together by laser welding. For this purpose, the externally located second joining section 22 is formed of (mostly) transparent material such that the laser beam 9 penetrates the second joining section 22 and most of the energy of the laser beam 9 can reach the internally located first joining section 21. This first joining section 21 melts and is joined to the externally located second joining section 22. On the opposite axial sides, this laser welding is carried out in the same manner.

[0045] Figure 4 is shown in an enlarged form Figure 3 the overlapping region 5, also denoted by IV in. Most of the overlapping region 5 is located between the circumferentially opposite pole shoes 3 of the two stator poles. In particular, the transparent or partially transparent partial section 221 of the second joining section 22 is located between the pole shoe side surfaces 31 that are opposite each other along the circumferential direction of the respective pole shoes 3. The opaque partial section 211 of the internally located first joining section 21 is axially located behind it (with respect to the incidence of the laser beam). Since the laser beam ( Figure 4 (not shown in) is incident from the left and penetrates the transparent partial section 221, the opaque partial section 211 melts in the contact region 10. This forms a molten region in the contact region 10. Thus, the first joining section 21 and the second joining section 22 are joined in a material-locking manner by laser welding.

[0046] The joining sections 21 and 22 are constructed on two opposite axial sides in such a way that, before welding, after the stator poles 11, 12 are plugged together, they are already pressed against each other. This produces the required contact pressure between the joining partners during the laser welding process.

[0047] In Figure 4 example, the transparent partial section 221 forms a cavity 222 that opens towards the center of the stator pole, i.e., towards the winding 6. In contrast, the opaque partial section 211 has a protrusion 212. In the example shown, the cross-sections of the cavity 222 and the protrusion 212 are both circular. However, the profiles of these two components can also be selected differently, for example, pointed. It is advantageous if the cavity 222 and the protrusion 212 are geometrically designed such that when the two stator poles 11 and 12 are plugged together, they engage with each other. The advantage of this is that the stator ring already remains together before welding. To ensure the contact pressure just mentioned, in the non-joined state of the two stator poles 11 and 12, the axial distance between the tips of the protrusions 212 should be slightly greater than the distance between the lowest points of the cavities 222 of the axially opposite transparent partial sections 221.

[0048] During the welding process, the laser beam is guided radially, for example, over the entire radial extent of the overlap region 5. This welding produces a media-tight joint at least on the axial side. On the outer circumference, the stator can be sealed in a suitable manner (also by overlapping and laser welding) to obtain a media-tight cooling circuit.

[0049] List of Reference Signs

[0050] 1 Stator pole

[0051] 2 Central axis

[0052] 3 Pole shoe

[0053] 4 (Plastic) injection molding

[0054] 5 Overlap region

[0055] 6 Winding

[0056] 7 Pole tooth

[0057] 8 Cavity or cooling chamber

[0058] 9 Laser beam

[0059] 10 Contact area

[0060] 11 First stator pole

[0061] 12 Second stator pole

[0062] 21 First joint section

[0063] 22 Second joint section

[0064] 31 Pole shoe side surface

[0065] 41 Overmolding with opaque material

[0066] 42 Overmolding with transparent material

[0067] 211 Opaque partial section

[0068] 212 Protrusion

[0069] 221 Transparent partial section

[0070] 222 Cavity

[0071] III Partial area

[0072] IV Partial area

Claims

1. A method for manufacturing at least a part of a stator for an axial flux machine, characterized in that, - attaching a first joining section (21) made of a first material to a first stator pole (11) of the stator, - attaching a second joining section (22) made of a second material to a second stator pole (12) of the stator, wherein, - in the joined state of the first stator pole (11) and the second stator pole (12), the first joining section (21) overlaps with the second joining section (22) in an overlapping region (5) in the circumferential direction of the stator, wherein, - the second joining section (22) is located more outwardly relative to the center of the stator than the first joining section (21), wherein, - the second material is at least mostly transmissive to a pre-given laser wavelength, - the first material is non-transmissive to the pre-given laser wavelength, and, - irradiating the overlapping region with a laser beam (9) of the pre-given laser wavelength, whereby the first joining section (21) is welded to the second joining section (22).

2. The method according to claim 1, characterized in that, the joining sections are welded such that the overlapping region (5) seals the cavity (8) between the two stator poles (11, 12) in a media-tight manner.

3. The method according to claim 1 or 2, characterized in that, the stator has a central axis (2) extending parallel to the respective main magnetic flux of the stator poles (11, 12), and the second joining section (22) is axially arranged outside the first joining section (21) relative to the central axis.

4. The method according to any one of the preceding claims, characterized in that, the stator poles (11, 12) are each provided with a winding (6) before welding.

5. The method according to any one of the preceding claims, characterized in that, the two stator poles (11, 12) are plugged into each other before welding, and the two joining sections (21, 22) are snap-connected to each other and / or form a form-fit.

6. A stator for an axial flux machine, characterized in that, - a first joining section (21) made of a first material on a first stator pole (11) of the stator, - a second joining section made of a second material on a second stator pole (12) of the stator, wherein, - in the joined state of the first stator pole (11) and the second stator pole (12), the first joining section (21) overlaps with the second joining section (22) in an overlapping region (5) in the circumferential direction of the stator, wherein, - the second joining section (22) is located more outwardly relative to the center of the stator than the first joining section (21), wherein, - the second material is at least mostly transmissive to a pre-given laser wavelength, - the first material is non-transmissive to the pre-given laser wavelength, and, - the first joining section (21) is welded to the second joining section (22).

7. The stator according to claim 6, characterized in that, - The first stator pole (11) has a joint section of the type of the first joint section (21) on the axially outer side on the side facing the second stator pole (12), and also has a joint section of the type of the first joint section (21) on the axially outer side on the opposite side, and - The second stator pole (12) has a joint section of the type of the second joint section (22) on the axially outer side on the side facing the first stator pole (11), and also has a joint section of the type of the second joint section (22) on the axially outer side on the opposite side.

8. The stator according to claim 6, characterized in that - The first stator pole (11) has a joint section of the type of the first joint section (21) on the axially outer side on the side facing the second stator pole (12), and has a joint section of the type of the second joint section (22) on the axially outer side on the opposite side, and - The second stator pole (12) has a joint section of the type of the second joint section (22) on the axially outer side on the side facing the first stator pole (11), and has a joint section of the type of the first joint section (21) on the axially outer side on the opposite side.

9. The stator according to claim 6, characterized in that - The first stator pole (11) has the first joint section and a joint section of the type of the second joint section (22) axially opposite thereto on the side facing the second stator pole (12), and on the opposite side has a joint section of the type of the second joint section (22) on the axially outer side opposite to the first joint section (21) in the circumferential direction, and a joint section of the type of the first joint section (21) axially opposite to the joint section of the second joint section 22 type, and - The second stator pole (12) has the second joint section (22) and a joint section of the type of the first joint section (21) axially opposite thereto on the side facing the first stator pole (11) type of joint section, and on the opposite side has a joint section of the type of the first joint section (21) on the axially outer side opposite to the second joint section (22) in the circumferential direction, and a joint section of the type of the second joint section (22) axially opposite to the joint section of the first joint section type.

10. The stator according to any one of claims 6 to 9, characterized in that The joint sections (21, 22) are molded onto the pole shoes (3) and / or pole teeth (7) of the corresponding stator poles (11, 12).

11. The stator according to any one of claims 6 to 10, characterized in that One of the two joint sections (21, 22) has a convex portion (212) in the overlapping region (5), and the other of the two joint sections has a cavity (222), wherein, in the joined state of the first stator pole (11) and the second stator pole (12), the convex portion (212) protrudes into the cavity (222).

12. The stator according to any one of claims 6 to 11, characterized in that the joining sections (21, 22) welded together along the entire radial extent of the stator poles (11, 12) in the overlapping region (5) seal the cooling circuit.

13. The stator according to any one of claims 6 to 12, characterized in that a tolerance gap is formed between the first joining section (21) and the second joining section (22) along the circumferential direction.

14. The stator according to any one of claims 6 to 13, characterized in that the two stator poles (11, 12) each have a winding (6), and the joining sections (21, 22) are arranged axially outside the windings (6) respectively.

15. An electric axial flux machine having a stator according to any one of claims 6 to 14.

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