Winding carrier, in particular stator, for an axial flux machine

Abstract

The invention relates to a winding support (3), in particular a stator, for an axial flux machine with a winding support yoke (6), from which winding support teeth (7) distributed circumferentially on one or both sides in the axial direction (a) project, with intermediate winding support grooves (9) in which at least one winding wire (11) is placed to form at least one winding (5), wherein the winding support (3) is designed in a segmented construction, in which a plurality of winding support segments (23; 23a, 23b) are joined together one after the other in a ring-shaped arrangement in a circumferential direction (u), wherein at least one winding support segment (23; 23a) can be equipped with the winding (5). According to the invention, the winding (5) of the winding carrier segment (23; 23a) is designed as a toroidal winding, in which the winding wire (11) is wound around the winding carrier yoke (6) in a toroidal winding technique.

Description

[0001] The invention relates to a winding support, in particular a stator, for an axial flux machine according to the preamble of claim 1.

[0002] Axial flux machines are well-known motor topologies that can be implemented in various configurations, such as an axial flux asynchronous machine. Axial flux machines can be essentially divided into three basic forms: a single-stator and single-rotor axial flux machine, a double-stator axial flux machine with two stators and one rotor, and a double-rotor axial flux machine with two rotors and one stator. These types of axial flux machines are characterized by their compact and flat design, high power density and efficiency, good cooling properties, and the ability to deliver high torque at low speeds.

[0003] For the purpose of simplified industrial manufacturing of such axial flux machines, it is known to construct the stator in segments. The stator segments can be manufactured as individual components, for example, with plastic attachments, and / or wound together in a single winding process. The stator segments can then be assembled to form the complete stator. During the manufacturing process, the individual stator segments can be subjected to quality control, allowing for the targeted and resource-efficient sorting out of defective segments, whereas a complete stator manufactured as a single unit would have to be entirely discarded.

[0004] However, the winding of the stator segments, which are provided as individual components, has proven problematic in the segmented design for the following reasons: The individual stator segments often have a complex geometry and irregular shape. These irregular shapes make winding the wires more difficult and require special winding techniques and machines, thus increasing the manufacturing effort.

[0005] WO 2016 / 034570 A1 discloses generic segmented stator components for an axial flux machine with a toroidal winding topology. The stator segments are designed such that their yoke areas rest against each other via support surfaces, thereby enabling a stable stator arrangement without a high-precision central ring.

[0006] From US 5 216 339 A, another winding carrier is known which is designed in a segmented construction.

[0007] The object of the invention is to provide a winding carrier, in particular a stator for an axial flux machine, which is structurally simple and can be manufactured in a process-reliable and technically simple manner with regard to mass production.

[0008] The problem is solved by the features of claim 1. Preferred embodiments of the invention are disclosed in the dependent claims.

[0009] The invention relates to a winding support, in particular a stator, for an axial flux machine with an annular winding support yoke, from which winding support teeth with intermediate winding support slots project in the axial direction, distributed circumferentially on one or both sides. Winding wires are laid in the winding support slots to form windings. The winding support is designed in a segmented construction, in which a plurality of winding support segments can be joined together one after the other in a ring-shaped arrangement in a circumferential direction during an assembly process. According to the invention, each of the winding support segments is wound with at least one winding designed as a toroidal winding, in which the winding wire is wound around the winding support yoke using a toroidal winding technique.

[0010] In a technical implementation, each of the winding carrier slots has a slot base and lateral slot flanks. The winding carrier slot is also axially open via a slot. The slot can be bounded by at least one circumferentially widened pole shoe of an adjacent winding carrier tooth, so that an undercut with an internal corner region is formed between the pole shoe and the adjoining slot flank. The pole shoe is preferably formed directly on the axial end face of the adjacent winding carrier tooth.

[0011] The winding carrier slots can be open radially inwards and radially outwards, and can be parallel-flanked, meaning with slot flanks parallel to each other. Alternatively and / or additionally, each of the winding carrier segments can be wedge-shaped, so that its circumferential width decreases wedge-shaped from the outer circumference of the segment towards the inner circumference.

[0012] Each of the winding carrier segments can be wound with the toroidal winding as a separate component before assembly. Alternatively, the toroidal winding is first produced separately from the winding carrier segment and then mounted onto the winding carrier segment.

[0013] For ease of assembly of the winding carrier, it is preferable for it to be constructed from as few different components as possible. Therefore, all winding carrier segments can be identical in design. Each winding carrier segment has two winding carrier teeth, each of which transitions into a segment base body at its tooth root. Viewed circumferentially, the segment base body has a contact surface on each side, which, in the assembled state, is in contact with a contact surface of the segment base body of the adjacent winding carrier segment. In the assembled state, the segment base bodies of the winding carrier segments thus form the winding carrier yoke.

[0014] Viewed in the circumferential direction, the segment base body has a base body projection on one winding side that extends beyond a groove flank of the winding support tooth by one profile height. The toroidal winding is guided in a ring shape around the base body projection. During the winding process, the winding wire is wound directly onto the base body projection to form the toroidal winding. Alternatively, the toroidal winding can first be manufactured as a separate component and then placed onto the base body projection. A transition step between the contact surface formed on the base body projection and the groove flank of the winding support tooth can form the groove base of the winding support tooth.

[0015] The segment side facing away from the winding side in the circumferential direction is designed as a flat surface, where the contact surface and the groove flank of the winding carrier tooth merge flush, thus forming a single, flat segment surface. Providing this flat segment surface allows the winding carrier segment to be machined using standardized machines and processes, reducing the need for special tools and fixtures. This, in turn, reduces manufacturing complexity and costs.

[0016] The pole shoe can be formed on the flat side facing away from the winding side in the circumferential direction. The pole shoe can project from the groove flank of the winding support tooth by one profile height in the circumferential direction, so that, in particular, the winding side of the winding support segment is designed without a pole shoe to enable interference-free winding of the winding support segment. The winding support segment can also be made from a laminated core with laminations stacked on top of each other in the radial direction of the winding support.

[0017] Cooling the winding support yoke is crucial for preventing overheating, maintaining efficiency, and ensuring the magnetic and mechanical properties of the machine. According to the invention, the winding support yoke has at least one cooling channel that runs radially through it. The cooling channel is integrated as a groove in one of the contact surfaces of the winding support segment, thus saving space and reducing the number of components. In the assembled state, the flow cross-section of the groove is closed by the contact surface of the adjacent winding support segment.

[0018] In a specific embodiment, the winding support is a stator of an axial flux machine, in particular an axial flux asynchronous machine. In a first embodiment, the axial flux machine can be designed as a twin-rotor machine with the stator and rotors arranged axially on both sides of the stator. In this case, circumferentially distributed stator teeth with intermediate stator slots can project from the stator yoke on both sides in the axial direction.

[0019] An embodiment of the invention is described below with reference to the attached illustrations. The illustrations show: Fig. 1, Fig. 2, Fig. 3, Fig. 4 to Fig. 5 a comparative example not covered by the invention; Fig. 6, Fig. 7, Fig. 8 to Fig. 9 an embodiment of the invention; and Fig. 10 and Fig. 11 comparative examples not covered by the invention.

[0020] In the Fig. Figure 1 illustrates an axial flux asynchronous machine to the extent necessary for understanding the invention. Accordingly, the axial flux machine is designed with a double-stator configuration, comprising a central rotor 1 and stators 3 arranged axially on both sides of the rotor 1. The rotor 1 and the two stators 3 are axially spaced apart from each other by a magnetically effective air gap. The rotor 3 is a conventional asynchronous rotor. Therefore, the rotor 3 contains no magnetic material and can be equipped with a classic squirrel-cage rotor or wound. Alternatively, the rotor can also be constructed from a solid material, which must conduct both magnetic fields and electric current. Steel can be used as an example. Alternatively, other suitable rotor topologies can also be employed.

[0021] The two stators 3 are designed to be mirror-symmetrical with respect to a plane passing centrally through the rotor 1. The stator windings 5 ​​are each wound as toroidal windings around the stator yoke 6 of the respective stator 3. Stator teeth 7 project axially from the stator yoke 6 towards the rotor 1.

[0022] Stator 3 is in the Fig. Figure 2 shows a section in the unwound state. Accordingly, the stator 3 has the annular stator yoke 6, from which the stator teeth 7 with intervening stator slots 9 project axially on one side towards the rotor 1, in which winding wires 11 ( Fig. 5) can be laid down to form the stator windings 5. Each of the stator slots 9 has a slot base 13 and lateral slot flanks 14, 15. In addition, each of the stator slots 9 is axially a-directed via a slot 17 ( Fig. 2) open design. The slot 17 is bounded by a pole shoe 19 of one of the adjacent stator teeth 7, which is widened in the circumferential direction u and is formed on its axial end face 20. This results in an undercut with an internal corner region 21 between the pole shoe 19 and the adjacent slot flank 15 ( Fig. 3) Each of the stator slots 9 is designed to be open radially inwards and radially outwards and is parallel-flanked, i.e., with slot flanks 14, 15 that are parallel to each other, so that the stator teeth 7 become wider in a wedge shape towards the outside in the radial direction r.

[0023] The unwound stator 3 is not designed as a single component, but rather in a segmented construction, in which a multitude of stator segments 23 are joined together one after the other in a ring-like arrangement in the circumferential direction u of the stator. All stator segments 23 are identical in construction. Furthermore, each of the stator segments 23 is made from a laminated core with laminations (not shown) stacked one above the other in a radial direction r.

[0024] The following is based on the Fig. Section 3 explains the segment geometry, which is designed for simple industrial mass production of the stator 3. Accordingly, the stator segment 23 has exactly one stator tooth 7. This tooth transitions at its root into a stator base body 25. The stator base body 25 has a contact surface 27, 28 on each side in the circumferential direction u. In the stator assembly state, the two contact surfaces 27, 28 are in contact with a corresponding contact surface 27, 28 of the stator base body 25 of the adjacent stator segment 23. Accordingly, in the stator assembly state, the stator base bodies 25 of all stator segments 23 together form the stator yoke 6.

[0025] In the Fig. 3 The segment base body 25, viewed in the circumferential direction u, is formed on a winding side W with a base body projection 29. The base body projection 29 extends beyond a slot flank 14 of the stator tooth 7 in the circumferential direction u by one profile height. The contact surface 27 formed on the base body projection 29 transitions at a transition step into the slot flank 14 of the stator tooth 7, which forms the slot base 13 of the stator tooth 7. A winding space open on one side is spanned between the slot base 13 and the slot flank 14, which allows for a disturbance-free, process-technically flawless feed of the winding wire 11 during the winding process ( Fig. 5) enabled.

[0026] In the wound state ( Fig. 4) The toroidal winding 5 is wound in a ring shape around the base body projection 29 around a winding axis A aligned perpendicular to the contact surface 27.

[0027] In the Fig. 3 The segment side facing away from the winding side W in the circumferential direction u is designed as a flat side F. On the flat side F of the stator segment 23, the contact surface 28 of the segment base body 25 and the groove flank 15 of the stator tooth 7 are flush with each other – without a transition step – resulting in a flat segment surface, which is advantageous in terms of manufacturing when handling the stator segment 23, compared to a segment side where the contact surface 28 is stepped towards the groove flank 15.

[0028] As from the Fig. As further shown in Figure 3, the pole shoe 19 is positioned on the flat side F of the stator segment 23, which faces away from the winding side W in the circumferential direction u. The pole shoe 19, which is formed directly on the axial end face 20 of the stator tooth 7, projects from the slot flank 15 by a profile height h in the circumferential direction u. In contrast, the winding side W of the stator segment 23 is designed without a pole shoe in order to enable a winding process free of interference contours.

[0029] To ensure the most homogeneous formation of the stator windings 5 ​​and the highest possible fill level in the stator slot 9 to be wound, a flat wire with a rectangular profile is used as the winding wire 11, as is found in the Fig. 5 is evident. The wire width corresponds approximately to the slot width of the stator slot 9 to be wound.

[0030] In the Fig. Figure 5 roughly schematically indicates a winding process in which the stator segment 23, provided as a single component, is wound with the winding wire 11. The winding process takes place in a winding machine (not shown), in which the winding wire 11 emerges from a winding die 31 under wire tension and is wound around the winding axis A ( Fig. 4) is wound onto the base body projection 29 of the stator segment 23. Due to the winding space of the stator segment 23 being open on one side, a simple winding wire guidance process is possible, in which the winding nozzle 31 moves in an easily controllable circular motion w ( Fig. 5) is moved around the base body projection 29 without an additional feed movement perpendicular to the contact surface 27 of the base body projection 29. Since the winding side W of the stator segment 23 is designed without pole shoes, precise and interference-free winding wire placement can be easily achieved during manufacturing. In the toroidal winding 4 thus produced, the individual winding wire turns 11 are laid in a single layer in alignment above one another, resulting in an extremely high fill level of the stator slot 9.

[0031] The segment geometry ensures precise and uniform winding during the winding process, with high repeatability for all stator segments 23 of the stator 3. This guarantees a uniform distribution of the magnetic flux in the stator 3, which increases the efficiency and performance of the axial flux machine.

[0032] The wound stator segment 23 is provided (before or after winding) with additional plastic components in a plastic molding process, which enable all stator segments 23 to be assembled into the stator 3 in an assembly process. Furthermore, the winding wire ends (of which in the Fig. (5 only one winding wire end 35 is shown) the stator-side toroidal windings 5 ​​are electrically interconnected in a manner known per se. However, it should be emphasized that the interconnection process can also take place before the assembly process. Alternatively and / or additionally, several stator segments 23 can also be wound consecutively without interruption of the winding wire.

[0033] In the preceding comparative example, each stator slot 9 is assigned exactly one toroidal winding 5. Alternatively, each stator slot 9 could also be assigned, for example, two toroidal windings 5. In this case, there would be four winding wire ends 35 per stator slot 9, which are to be connected in the wiring process.

[0034] Based on the Fig. 6, Fig. 7, Fig. 8 to Fig. Figure 9 shows an embodiment in which the axial flux asynchronous machine is not implemented in a double-stator design, but rather in a double-rotor design, namely with a stator 3 and rotors 1 arranged axially on both sides of the stator 3. The Fig. 6, Fig. 7, Fig. 8 to Fig. The double-rotor design shown in Figure 9 offers increased conductor material utilization compared to the double-stator design ( Fig. 1, Fig. 2, Fig. 3, Fig. 4 to Fig. 5) is preferable. In the double-stator design, only the conductor portion located in stator slot 9 is used, while the entire back side of the conductor remains unused. In contrast, the double-rotor design utilizes the conductor material much more efficiently.

[0035] The stator windings 5 ​​are in the Fig. 6, as in the previous comparative example, is also designed as toroidal windings. The geometry of stator 3 corresponds in principle to the geometry of stator 3 used in the double-stator design, so reference is made to the previous description. In contrast to the previous comparative example, axially distributed stator teeth 7 with intervening stator slots 9 project from both sides of the annular stator yoke 6.

[0036] In the Fig. 7 and Fig. 8 are shown in views according to the Fig. 2 and Fig. Figure 3 shows a section of an unwound stator 3 with three stator segments 23 arranged one behind the other, as well as a stator segment 23 on its own. Accordingly, a stator tooth 7 is formed on each side of the segment base body 25 in the axial direction a. Each of the stator teeth 7 has a pole shoe 19 on its axial end face 20. The two pole shoes 19 project circumferentially u from the flat side F of the stator segment 23 by a profile height.

[0037] As from the Fig. 7 and Fig. As further shown in Figure 8, a groove 33 is machined into the contact surface 28 of the stator segment 23, extending in the radial direction r over the entire contact surface 28. The groove cross-section is determined in the assembled state ( Fig. 7) closed by the contact surface 27 of the adjacent stator segment 23. In the assembled state, the groove 33 acts as a cooling channel, which is integrated into a coolant circuit of the axial flux machine. The cooling channel, through which coolant flows, allows for the effective cooling of the winding heads of the stator windings 5 ​​in particular.

[0038] In contrast to the illustrated embodiment, in a comparative example not shown, the stator slot 14 can extend centrally through the stator tooth 7. In this case, the winding wire 11 would have to be guided through the circumferentially closed stator slot 15 in a significantly more complex wire guide during the winding process.

[0039] In another comparative example not shown, the pole shoe 19 may protrude not from the flat side F, but from the winding side W of the stator segment 23. In this case, however, the winding process would also be more complex and subject to interference contours.

[0040] In the Fig. In the comparative example 10, which is not covered by the invention, two stator segments 23a, 23b are shown, which are part of a stator 3, as in the Fig. 6, Fig. 7, Fig. 8 to Fig. 9 is designed in a twin-rotor configuration. In contrast to the previous embodiment, in the Fig. 10. The stator 3 is not made of identical segments 23, but, viewed in the circumferential direction u, is alternately constructed with the differently designed segments 23a, 23b, the geometry of which is subsequently described based on the Fig. As described in section 10: Segment 23a is basically analogous to segments 23 of the Fig. 7, Fig. 8 to Fig. 9 trained, so reference is made to their preliminary description. In contrast to the Fig. 7, Fig. 8 to Fig. 9, segment 23a, viewed in the circumferential direction u, is wound on both sides with a winding 5 each.

[0041] Accordingly, the segment base body 25 of segment 23a, viewed in the circumferential direction u, is formed on both sides with a base body projection 29. Each of the base body projections 29 extends beyond – analogously to the Fig. 7 and Fig. 8 - a groove flank 14 of the stator tooth 7 in the circumferential direction u by one profile height. The contact surface 27 formed on the respective base body projection 29 transitions at a transition step into the groove flank 14 of the stator tooth 7, which forms the groove base 13 of the stator tooth 7. Between the groove base 13 and the groove flank 14, a winding space open on one side W is provided on each winding side, which enables interference-free, process-technically flawless feeding of the winding wire 11 during the winding process.

[0042] In the Fig. In the wound state shown in Figure 10, each of the toroidal windings 5 ​​is wound in a ring shape around the base body projection 29 around a winding axis A oriented perpendicular to the contact surface 27.

[0043] In contrast, segment 23b, viewed in the circumferential direction u, is formed on both sides with a flat side F. On each of the flat sides F of the stator segment 23b, the contact surface 28 of the segment base body 25 and the groove flank 15 of the stator tooth 7 are flush with each other – without a transition step – resulting in a flat segment surface on both sides.

[0044] In the Fig. In section 10, the pole shoes 19 of the stator 3 are omitted. To enable a winding process free of interference contours, a pole shoe 19 can be positioned on each of the flat sides F of segment 23b, while segment 23a remains pole shoe-free.

[0045] In the Fig. In the comparative example 11, which is not covered by the invention, a stator segment 23 is shown, which is also part of a stator 3, as in the Fig. 6, Fig. 7, Fig. 8 to Fig. 9 is designed in a double-rotor configuration and is formed from a multitude of identical stator segments 23. Therefore, reference is made to the preliminary description, which also concerns stator segments 23 in a double-rotor configuration.

[0046] As from the Fig. As can be seen from Figure 11, the stator segment 23, viewed in the circumferential direction u, is formed on both sides with flat sides F. The stator segment 23 has two half-teeth 37, which are spaced apart from each other in the circumferential direction u by a stator groove 9, which is wound with a winding 5.

[0047] In the assembled state, a multitude of such stator segments 23 are arranged one behind the other in the circumferential direction u. The stator segments 23 are in contact with each other with their flat sides F, so that two adjacent half-teeth 37 each form a stator tooth 7.

[0048] The in the Fig. 10 or Fig. The 11 indicated segment geometries are significantly more complex than those in the Fig. 1, Fig. 2, Fig. 3, Fig. 4, Fig. 5, Fig. 6, Fig. 7, Fig. 8 to Fig. The 9 segment geometries shown. Therefore, in the Fig. 10 or Fig. The standardized machining tools and / or processes indicated for the 11 segment geometries are no longer readily applicable to the geometrically complex stator segment 23, 23a. Reference number list 1 Rotor 3 Stator 5 Stator winding 6 Stator yoke 7 Stator tooth 9 Stator slot 11 winding wire 13 Groove 14, 15 groove flanks 17 slotted grooves 19 Polschuh 20 axial face of the stator tooth 21 Inside corner area 23, 23a, 23b Stator segment 25-segment base body 27, 28 contact surfaces 29 Base body overhang 31 winding nozzle 33 Nut 35 winding wire end 37 half-teeth a axial direction r radial direction u circumferential direction w Movement path of the winding nozzle A winding axis W winding side F Flat side R Rotor axis h Profile height

Claims

[1] Winding support (3), in particular stator, for an axial flux machine with a winding support yoke (6) from which, in the axial direction (a), circumferentially distributed winding support teeth (7) with intermediate winding support slots (9) project on both sides, in which at least one winding wire (11) is placed to form at least one winding (5), wherein the winding support (3) is designed in a segmented construction, in which a plurality of winding support segments (23) are joined together one after the other in a ring-shaped arrangement in a circumferential direction (u), wherein at least one winding support segment (23) can be equipped with the winding (5), wherein the winding (5) of the winding support segment (23) is designed as a toroidal winding, in which the winding wire (11) is wound around the winding support yoke (6) in a toroidal winding technique, wherein at a The segment base body (25) viewed in the axial direction (a) has a winding carrier tooth (7) formed on both sides,wherein each of the two winding carrier teeth (7) transitions at its tooth base into a segment base body (25), and wherein the segment base body (25) has a contact surface (27, 28) on both sides when viewed in the circumferential direction (u), which in the assembled state is in contact with a contact surface (27, 28) of the segment base body (25) of the adjacent winding carrier segment (23), so that in the assembled state the segment base bodies (25) of the winding carrier segments (23) form the winding carrier yoke (6), , characterized by, that, viewed in the circumferential direction (u), the segment base body (25) is formed on exactly one winding side (W) with a base body projection (29) which extends beyond a groove flank (14) of the winding support tooth (7) in the circumferential direction (a) by a profile height, and that the toroidal winding (5) is guided in a ring shape around the base body projection (29), and that the winding support yoke (6) has at least one cooling channel (33) which is guided through the winding support yoke (6) in the radial direction (r), wherein the cooling channel (33) is formed as a groove in one of the contact surfaces (27, 28) of the winding support segment (23), and wherein the flow cross-section of the groove is closed by the contact surface (27, 28) of the adjacent winding support segment (23) in the assembled state. [2] Winding carrier (3) according to claim 1, characterized by, that each of the winding carrier slots (9) has a slot base (13) and lateral slot flanks (14, 15) and is designed to be open in the axial direction (a) via a slot (17), and that in particular the slot (17) is limited by at least one pole shoe (19) of an adjacent winding carrier tooth (7) which is widened in the circumferential direction (u), so that an undercut with an internal corner area (21) is formed between the pole shoe (19) and the adjacent slot flank (15), and / or that the pole shoe (19) is formed on the axial end face (20) of the adjacent winding carrier tooth (7). [3] Winding carrier (3) according to claim 1 or 2, characterized by, that the winding carrier slots (9) are designed to be open radially inwards and radially outwards and in particular are parallel-flanked, i.e. with slot flanks (14, 15) that are parallel to each other, and / or that each of the winding carrier segments (23) is wedge-shaped, so that its circumferential width is reduced wedge-shaped from the outer circumference of the segment towards the inner circumference of the segment. [4] Winding carrier (3) according to any one of the preceding claims, characterized by , that each of the winding carrier segments (23) can be formed as a separate component before assembly with the toroidal winding (5). [5] Winding carrier (3) according to any one of the preceding claims, characterized by, that in a winding process the winding wire (11) can be wound directly onto the base body protrusion (29) to form the toroidal winding (5), or that in the winding process the toroidal winding (5) can first be produced as a separate component, and then placed onto the base body protrusion (29). [6] Winding carrier (3) according to any one of the preceding claims, characterized by , that the segment side facing away from the winding side (W) in the circumferential direction (u) is designed as a flat side (F) in which the contact surface (28) and the groove flank (15) of the respective winding carrier tooth (7) merge flush into each other, i.e. forming a flat segment surface, which simplifies the handling of the winding carrier segment (23) in terms of manufacturing technology. [7] Winding carrier (3) according to claim 6, characterized by, that the pole shoe (19) is formed on the flat side (F) of the winding carrier segment (23), and that the pole shoe (19) projects from the groove flank (15) of the winding carrier tooth (7) by a profile height (h) in the circumferential direction (u), so that the winding side (W) of the winding carrier segment (23) is designed without pole shoes in order to enable interference contour-free winding of the winding carrier segment (23). [8] Winding carrier (3) according to any one of the preceding claims, characterized by , that the winding carrier (3) is a stator of an axial flux machine, and that the axial flux machine is designed in a double-rotor construction with the stator (3) and with rotors (1) arranged axially on both sides of the stator (3), and that the winding carrier teeth (7) project from the stator yoke (6) as stator teeth distributed circumferentially on both sides in the axial direction with intermediate stator slots (9).

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