Stator system of axial flux motor

Abstract

The invention relates to a stator system of an axial magnetic flux motor, in particular to the technical field of new energy automobile driving motors, a stator winding coil comprises a plurality of flat wire coils, each coil is in an isosceles triangle shape, two bottom forming angles of each isosceles triangle are both larger than 60 degrees, and the bending radius in the forming process of the flat wire coils is smaller than one time of the wire width; the end wiring copper bar assembly is used for connecting the flat wire coil; the segmented stator iron core group without the rear yoke comprises a plurality of iron core units, the iron core units are independently arranged at intervals, a full-open slot design is adopted between every two adjacent iron core units, and flat wire coils of stator winding coils and the iron core units of the segmented stator iron core group are nested one by one to form windings. According to the stator system of the axial magnetic flux motor, the segmented stator iron core sets of the full-open-slot yoke-free structure are adopted, the stator winding coils are embedded in the iron cores in a flat wire vertical winding mode, the axial structure is more compact, and the power density and the torque density of the motor are greatly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of drive motors for new energy vehicles, and particularly to a stator system of an axial flux motor. Background Art

[0002] With the popularity of concepts such as distributed systems and in-wheel drive, axial flux motors have become a research hotspot due to their compact space, high torque density, and high power density. Since there is a large axial suction force between a single stator and a rotor of an axial flux motor, the new energy vehicle motor industry mostly adopts a symmetric stator-rotor disc topology structure to offset the axial force of the entire motor, thereby increasing the stability of the shafting and the electric drive system. Under the same performance level, compared with radial motors, axial motors can more than double the torque density of the motor, shorten the axial dimension by more than 50%, and reduce the weight to less than 1 / 3 of the original, enabling a more compact motor structure and assembly structure, reducing the vehicle mass, and increasing the vehicle's cruising range.

[0003] In related technologies, the mainstream axial flux motor topology structure in the new energy industry is divided into single stator and double rotors. The structure of the single stator is similar to Figure 1 the structure shown. The yoke a is arranged in a ring shape, and the stator teeth b protrude axially from the surface of the yoke a along the axial direction of the yoke a. The stator teeth b include a plurality of them, and the plurality of stator teeth b are arranged at intervals along the circumferential direction of the yoke a and enclose to form a winding groove c. A flange d extending along the width direction of the stator tooth b is provided at the end of the stator tooth b away from the yoke a. The stator winding coil is wound around the stator tooth b.

[0004] However, the above single stator structure occupies a relatively large radial space, which will squeeze the space of electromagnetic components (iron core, winding, permanent magnet, etc.) in the structural design, resulting in a decline in the output performance of the motor; with the development of technology, new energy vehicles have put forward higher performance requirements for the power density and torque density of axial flux motors. The above single stator structure cannot meet the demand for further improving the power density and torque density. Summary of the Invention

[0005] The present application provides a stator system of an axial flux motor, which adopts a segmented stator iron core group with a full open slot and no yoke structure. The stator winding coil is nested in the iron core by using a flat wire vertical winding method, and the axial structure is more compact, greatly improving the power density and torque density of the motor.

[0006] The present application discloses a stator system of an axial flux motor. The stator system adopts a three-phase symmetric topology structure, which includes: a stator winding coil, including a plurality of flat wire coils that are flat along the axial direction. Each coil is an isosceles triangle, and both bottom forming angles of the isosceles triangle are greater than 60°, and the bending radius during the forming process of the flat wire coil is less than one wire width.

[0007] The end-wiring copper bar assembly is used to route and connect the flat wire coils of the stator winding coils according to a three-phase symmetrical topology structure, and lead out and connect the three-phase flexible copper wires outside.

[0008] The segmented stator core group without a rear yoke includes several core units, each core unit is independently and spaced apart, and a full-open slot design is adopted between adjacent two core units. The flat wire coils of the stator winding coils are nested one by one with the core units of the segmented stator core group to form windings.

[0009] On the basis of the above technical solution, after the flat wire coils of the stator winding coils with the end-wiring copper bar assembly are nested in the segmented stator core group, impregnation treatment is carried out to form an overall impregnated structure; and connection holes for facilitating connection of the three-phase flexible copper wires are reserved in the overall impregnated structure.

[0010] On the basis of the above technical solution, a set gap exists between the flat wire coils. When impregnation treatment is carried out, an insulating glue layer is filled in the set gap.

[0011] On the basis of the above technical solution, the radii of the three inner rounded corners of the flat wire coil are the same, and the radius of the inner rounded corner is less than the width of the flat wire.

[0012] On the basis of the above technical solution, the end-wiring copper bar assembly uses a string-wired copper bar routing method or a continuous wave-band routing method to connect multiple windings.

[0013] On the basis of the above technical solution, the stator system includes 3(2n + 2) windings, which are divided into 3(n + 1) forward-wound windings and 3(n + 1) reverse-wound windings, where n is a positive integer greater than or equal to 1; the end-wiring copper bar assembly includes several short-span copper bars and several long-span copper bars, and all windings are symmetrically distributed around the center; the adjacent windings of the same phase among the 3(n + 1) forward-wound windings or the 3(n + 1) reverse-wound windings are connected by short-span copper bars; the long-span copper bars connect the windings of the same phase at intervals.

[0014] On the basis of the above technical solution, the end-wiring copper bar assembly further includes a center copper bar. The short-span copper bars and the long-span copper bars connect the adjacent or spaced windings of the same phase; the center copper bar connects the three-phase current after the short-span copper bars and the long-span copper bars are connected; the center copper bar, the short-span copper bars and the long-span copper bars are arranged at intervals in a three-layer layout along the axial direction of the stator winding coil, and the center copper bar is located in the middle.

[0015] On the basis of the above technical solution, the end-wiring copper bar assembly adopts a string-wired copper bar routing method or a continuous wave-wound routing method. In the case of the string-wired copper bar routing method, the end-wiring copper bar assembly is independent of the stator winding coil; in the case of the continuous wave-wound routing method, the end-wiring copper bar assembly and the stator winding coil are integrated.

[0016] Based on the above technical solution, when n is equal to 2, the winding numbers are sequentially 1 to 12 in the counterclockwise direction, and the phases to which the windings numbered 1 to 12 belong and the positive and negative directions of the current are sequentially U+, U-, V-, V+, W+, W-, U-, U+, V+, V-, W- and W+.

[0017] Based on the above technical solution, the iron core unit is pressed from a soft magnetic composite material.

[0018] The beneficial effects brought by the technical solution provided by the embodiments of the present application at least include:

[0019] 1. For the stator system of the present application, a unique design is carried out. On the one hand, the stator winding coils use flat wire coils that are flat along the axial direction to replace the round wire solution in traditional axial motors. Therefore, there is no need to install a non-metallic skeleton for fixing the round wire in the slot, which simplifies the structure. At the same time, the flat wire coils greatly reduce the axial dimension compared with the round wire coils, making the structure more compact. Further, each flat wire coil is an isosceles triangle, and the apex forming angle of the isosceles triangle is close to the inner circle side of the stator, and the two bottom forming angles are close to the outer circle side of the stator, and both bottom forming angles are greater than 60° (the corresponding bottom bending angle is greater than 90°), and the apex forming angles are all less than 60° (the corresponding apex bending angle is greater than 120°), and the bending radius during the forming process of the flat wire coil is less than one wire width. Each flat wire coil adopts a pre-forming method, and the final shape and fillet size are directly processed through a flat wire coil mold. In order to maximize the output performance and reduce the saturation degree of the stator core, the specific shape of the flat wire coil can maximize the cross-sectional area of a single iron core unit, spread as much as possible along the radial direction, and at the same time reduce the axial dimension. On the other hand, the segmented stator core group adopts a design without a back yoke, which is lighter in overall weight and uses less material. At the same time, with the design without a back yoke, the thickness dimension of the original yoke part is vacated, and the overall axial dimension is small, making the structure more compact. On the third hand, a fully open slot design is adopted between adjacent two iron core units, which can make the wire embedding more convenient and more feasible in terms of process. Compared with the traditional stator core with a flange d at the axial end face, the segmented stator core group adopts a fully open slot design, which greatly reduces the wire embedding difficulty.

[0020] 2. For the stator system of the present application, after the flat wire coils of the stator winding coils with an end-wiring copper bar assembly are nested in the segmented stator core group, impregnation treatment is carried out to form an integral impregnated structure, making the overall structure stable and reliable.

[0021] 3. The stator system of the present application. By adopting a relatively large set gap between layers for the flat wire coil, the processing difficulty is reduced, and the insulation and heat conduction performance are enhanced. Specifically, due to the relatively high design and process difficulty of the large bending angle of the flat wire coil, there is also a relatively large extrusion deformation amount inside the bending part of the flat copper wire. Therefore, the interlayer gap of the flat wire coil is adjusted for the design of the large bending angle, and a relatively large set interlayer gap is adopted. The winding paint film material also uses a material with good ductility and adhesion. Through overall dipping treatment, the gaps between winding layers will be filled with insulating glue, and the insulation performance, heat conduction performance, and overall strength will all be greatly improved.

[0022] 4. The stator system of the present application. The radii of the three inner rounded corners of the flat wire coil are all the same, which can greatly reduce the processing difficulty, and all the radii are less than one times the width of the flat wire, which can increase the radial spreading area as much as possible, thereby reducing the axial dimension, and greatly reducing the overall axial dimension of the stator structure, and then improving the power density and torque density.

[0023] 5. The stator system of the present application. By adopting the way of staggered connection of long-span copper bars and short-span copper bars, the complexity of the copper bars is greatly simplified. Among them, two adjacent windings in the same phase are connected by short-span copper bars, and two windings separated by one winding in the same phase are connected by long-span copper bars. The structural dimensions of each short-span copper bar are basically the same, and the structural dimensions of each long-span copper bar are basically the same, which greatly reduces the processing and assembly difficulty and the wiring difficulty. Similarly, such an end-wiring copper bar assembly also reduces the axial dimension, indirectly improving the motor power density and torque density.

[0024] 6. The stator system of the present application. The central copper bar, short-span copper bars, and long-span copper bars are arranged in a three-layer layout along the axial direction of the stator winding coil, effectively avoiding mutual interference between the three-phase windings in space. The end outer envelope of the entire stator system is more compact, the outer envelope diameter is compressed to the maximum, and the entire structure is more compact, laying a foundation for further improving the power density and torque density. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained according to these drawings.

[0026] Figure 1 It is a schematic structural diagram of the yoke and stator teeth in the prior art;

[0027] Figure 2 It is a schematic diagram of the stator winding coil and the segmented stator iron core group provided by the embodiment of the present application;

[0028] Figure 3Schematic diagram of the assembled stator system provided by the embodiment of the present application;

[0029] Figure 4 is Figure 3 left view of;

[0030] Figure 5 Schematic diagram of the structures of the forward-wound coil and reverse-wound coil provided by the embodiment of the present application;

[0031] Figure 6 Connection schematic diagram of the stator winding coils connected through the end-wiring copper bar assembly provided by the embodiment of the present application;

[0032] Figure 7 Schematic diagram of the structure of the end-wiring copper bar assembly when using the string-wiring copper bar wiring method;

[0033] Figure 8 Schematic diagram of the structure of the stator winding coils when using the continuous wave winding wiring method provided by the embodiment of the present application;

[0034] Figure 9 Schematic diagram of the short span, long span and outgoing copper bar of the U phase of the continuous wave winding wiring method provided by the embodiment of the present application;

[0035] Figure 10 Schematic diagram of the short span, long span and outgoing copper bar of the V phase of the continuous wave winding wiring method provided by the embodiment of the present application;

[0036] Figure 11 Schematic diagram of the short span, long span and outgoing copper bar of the W phase of the continuous wave winding wiring method provided by the embodiment of the present application;

[0037] In the figure: a, yoke; b, stator tooth; c, winding slot; d, flange;

[0038] 1, stator winding coil; 11, forward-wound coil; 12, reverse-wound coil;

[0039] 121, reverse one-port; 122, reverse two-port;

[0040] 111, forward one-port; 112, forward two-port;

[0041] 2, end-wiring copper bar assembly; 21, center copper bar; 22, three-phase soft copper wire;

[0042] 20, short-span copper bar; 200, long-span copper bar;

[0043] 211, wave-wound short-span copper bar; 212, wave-wound long-span copper bar; 213, phase outgoing copper bar;

[0044] 3, segmented stator iron core group; 31, iron core unit. Detailed implementation mode

[0045] In order to enable those skilled in the art to better understand the solution of this application, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are only a part of the embodiments of this application, rather than all the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of this application.

[0046] The embodiment of this application provides a stator system of an axial-flux motor. By designing a brand-new stator system, the existing torque density and power density of the axial-flux motor on the market are broken through, and it can be verified by experiments that it can be increased by more than 40%.

[0047] Specifically, at the initial design, a distributed electric drive assembly with a peak torque ≥ 8500 Nm and a peak power ≥ 450 kW is to be designed within a space range where the outer envelope size does not exceed 480 mm × 530 mm × 400 mm. The corresponding peak torque density of the axial-flux motor is ≥ 28 Nm / kg, the power density is ≥ 10 kW / kg, and the axial dimension of the motor is ≤ 100 mm. However, using the traditional single-stator structure as Figure 1 shown for design cannot achieve the performance indicators of the design goal. Therefore, the axial dimension of the stator system needs to be as small as possible and the structure needs to be as compact as possible. After adopting the stator system of this application, the performance indicators of the above design goal are successfully achieved, breaking through the existing torque density and power density of the axial-flux motor on the market, and it can be verified by experiments that it can be increased by more than 40%.

[0048] Furthermore, for the stator system of the axial-flux motor of this application, in order to make the axial dimension of the stator system as compact as possible, the stator core adopts a segmented stator core group with a full-open slot and no yoke structure. The stator winding coil adopts a flat wire vertical winding method and is nested in the core, making the axial structure more compact and greatly improving the power density and torque density of the motor.

[0049] As Figures 1 to 11 shown, this application discloses an embodiment of a stator system of a high-torque density axial-flux motor. The stator system includes a stator winding coil 1, an end-wiring copper bar assembly 2, and a segmented stator core group 3.

[0050] Among them, the stator winding coil 1 includes a number of axially flat flat wire coils. Each flat wire coil is an isosceles triangle, and the apex forming angle of the isosceles triangle is close to the inner circle side of the stator, and the two bottom forming angles are close to the outer circle side of the stator. Both bottom forming angles are greater than 60° but less than 90° (the corresponding bottom bending angle is greater than 90°), and the bending radius during the forming process of the flat wire coil is less than one wire width.

[0051] The stator winding coil 1 of this application uses a flat wire coil that is axially flat to replace the round wire solution in traditional axial motors. Therefore, there is no need to install a non-metallic skeleton for fixing the round wire in the slot, which simplifies the structure. At the same time, the flat wire coil greatly reduces the axial dimension compared to the round wire coil, making the structure more compact. Further, each flat wire coil is an isosceles triangle, and the apex forming angle of the isosceles triangle is close to the inner circle side of the stator, and the two bottom forming angles are close to the outer circle side of the stator, and both bottom forming angles are greater than 60° but less than 90°. And the bending radius during the forming process of the flat wire coil is less than one wire width. Each flat wire coil adopts a pre-forming method, and the final shape and fillet size are directly processed through a flat wire coil mold. In order to maximize the output performance and reduce the saturation degree of the stator core, the specific shape of the flat wire coil can maximize the cross-sectional area of a single core unit 31, spread as much as possible along the radial direction, and at the same time reduce the axial dimension.

[0052] Specifically, the bottom forming angle refers to the base angle of the isosceles triangle as shown in Figure 3 , and the bottom bending angle refers to the supplementary angle of the bottom forming angle, that is, the angle that the flat wire coil needs to bend when processing from a straight line to the Figure 3 state of the bottom forming angle.

[0053] The end-wiring copper bar assembly 2 is used to route and connect the flat wire coils of the stator winding coil 1 according to a three-phase symmetric topological structure, and lead out and connect the three-phase flexible copper wires 22 outside.

[0054] The segmented stator core group 3 adopts a design without a back yoke, that is, the yoke part a as shown in Figure 1 , to reduce the axial dimension. The segmented stator core group 3 includes several core units 31, and each core unit 31 is independently and spaced apart. A full-open slot design is adopted between two adjacent core units 31, that is, the core unit 31 has a flange d structure as shown in Figure 1 . The winding slot c formed between two adjacent core units 31 is not restricted by the flange d. The flat wire coils of the stator winding coil 1 are nested one by one with the core units 31 of the segmented stator core group 3 to form a winding, that is, each winding is formed by winding a flat wire coil around a core unit 31.

[0055] Specifically, the core unit 31 is also an isosceles triangle, and the shape and size of the core unit 31 are adapted to the shape and size inside the flat wire coil.

[0056] The stator system of the present application is uniquely designed. In the first aspect, the stator winding coil 1 adopts a flat wire coil that is flat along the axial direction to replace the round wire solution in traditional axial motors. Therefore, there is no need to install a non-metallic skeleton for fixing the round wire in the slot, which simplifies the structure. At the same time, the flat wire coil greatly reduces the axial dimension compared with the round wire coil, making the structure more compact. Further, each flat wire coil is in an isosceles triangle shape, and the top forming angle of the isosceles triangle is close to the inner circle side of the stator, and the two bottom forming angles are close to the outer circle side of the stator, and both bottom forming angles are greater than 60° but less than 90° (the corresponding bottom bending angle is greater than 90°), and the top forming angles are all less than 60° (the corresponding top bending angle is greater than 120°), and the bending radius during the forming process of the flat wire coil is less than one wire width. Each flat wire coil adopts a pre-forming method, and the final shape and fillet size are directly processed through a flat wire coil mold. In order to maximize the output performance and reduce the saturation degree of the stator core, the specific shape of the flat wire coil can maximize the cross-sectional area of a single core unit 31, spread as much as possible along the radial direction, and at the same time reduce the axial dimension. In the second aspect, the segmented stator core group 3 adopts a design without a rear yoke, which is lighter in overall weight and uses less material. At the same time, with the design without a rear yoke, the thickness dimension of the original yoke part is vacated, and the overall axial dimension is small, making the structure more compact. In the third aspect, a full-open slot design is adopted between two adjacent core units 31, which can make the wire embedding more convenient and more feasible in terms of process. Compared with the traditional stator core with a flange d at the axial end face, the segmented stator core group 3 adopting a full-open slot design greatly reduces the wire embedding difficulty.

[0057] Further, in an embodiment, after the flat wire coil of the stator winding coil 1 of the end-wire copper bus assembly 2 is embedded in the segmented stator core group 3, impregnation treatment is carried out to form an overall impregnated structure; and connection holes are reserved in the overall impregnated structure for facilitating the connection of the three-phase flexible copper wires 22.

[0058] Specifically, in the case of the series-wire copper bus wiring method, first connect the end-wire copper bus assembly 2 as shown in Figure 7 to the stator winding coil 1, then nest the segmented stator core group 3, and then carry out impregnation treatment. Among them, the end-wire copper bus assembly 2 is connected to the stator winding coil 1 and forms the wiring relationship in Figure 6 .

[0059] Specifically, the core units 31 of the segmented stator core group 3 will be nested with the flat wire coils of the stator winding coil 1 one by one. The effect after nesting is as shown in Figure 3 . After that, impregnation treatment will be carried out to fill the gaps between the stator winding coil 1 and the segmented stator core group 3, as well as the interlayer gaps inside the stator winding coil 1, so as to improve the strength and stiffness of the entire overall impregnated structure; after impregnation and curing, the stator winding coil 1 and the segmented stator core group 3 will be connected to the three-phase flexible copper wires 22.

[0060] For the stator system of the present application, after the flat wire coils of the stator winding coils 1 with the end-wiring copper bar assembly 2 are nested in the segmented stator core group 3, impregnation treatment is carried out to form an overall impregnated structure, making the overall structure stable and reliable.

[0061] As Figure 5 shown, further, there is a set gap between the layers of each flat wire coil itself. When impregnation treatment is carried out, the insulating glue layer is filled in the set gap.

[0062] For the stator system of the present application, the flat wire coils adopt a relatively large set gap between the layers, reducing the processing difficulty and enhancing the insulation and heat conduction performance; specifically, due to the relatively high design process difficulty of the large bending angles of the flat wire coils (the bottom bending angle is greater than 90° and the top bending angle is greater than 120°), there is also a relatively large extrusion deformation amount inside the bending part of the flat copper wire. Therefore, the interlayer gap of the flat wire coils is adjusted for the design of the large bending angles, and a relatively large set interlayer gap is adopted. The winding paint film material also uses a material with good ductility and adhesion; through overall impregnation treatment, the gaps between the winding layers will be filled with insulating glue, and the insulation performance, heat conduction performance, and overall strength will all be greatly improved.

[0063] Further, to reduce the processing difficulty of the winding, at the top angle and the bottom edge of the isosceles triangle of the flat wire coil and the iron core unit 31, no arc treatment is done to fit the shape of the rotor disc, but a straight-line design method is adopted, greatly reducing the processing difficulty.

[0064] In one embodiment, the radii of the three inner rounded corners of the flat wire coil are the same, reducing the processing difficulty, and all the radii are less than one times the width of the flat wire, as much as possible increasing the radial spreading area and reducing the axial dimension. Specifically, although the radii of the three inner rounded corners of the flat wire coil are the same, the bending arcs are different, and the bending arc of the top angle is greater than that of the other two angles.

[0065] The rounded corner sizes at the two bottom edges of the isosceles triangle iron core unit 31 are the same as those of the flat wire coil to achieve the best fitting effect.

[0066] For the stator system of the present application, the radii of the three inner rounded corners of the flat wire coil are the same, which can greatly reduce the processing difficulty, and all the radii are less than one times the width of the flat wire, which can as much as possible increase the radial spreading area, thereby reducing the overall axial dimension of the stator structure, and further improving the power density and torque density.

[0067] Further, in one embodiment, the end-wiring copper bar assembly 2 adopts a string-wired copper bar wiring method or a continuous wave-band wiring method to connect multiple said windings.

[0068] Specifically, the connection relationships of the two wiring methods are both as Figure 6As shown, the structures of the end-wiring copper bar assemblies 2 in the two winding directions are different, and both winding methods can ensure that the stator system forms a three-phase symmetrical topological structure.

[0069] Furthermore, in one embodiment, the stator system includes 3(2n + 2) windings, which are divided into 3(n + 1) forward windings and 3(n + 1) reverse windings, where n is a positive integer greater than or equal to 1. Among them, the forward winding includes a forward winding coil 11 and an iron core unit 31, and the reverse winding includes a reverse winding coil 12 and an iron core unit 31.

[0070] Among them, the end-wiring copper bar assembly includes a number of short-span copper bars 20 and a number of long-span copper bars 200, and all windings are symmetrically centered with positive and negative (see Figure 3 ). The short-span copper bars 20 connect the adjacent windings of the same phase among the 3(n + 1) forward windings or the 3(n + 1) reverse windings. For example, Figure 3 in the short-span copper bar 20 connects the adjacent No. 1 winding and No. 2 winding; the long-span copper bar 200 connects the windings of the same phase at intervals. For example, Figure 3 in the long-span copper bar 200 connects the No. 2 winding and the No. 7 winding at intervals.

[0071] For the stator system of the present application, the stator windings adopt two vertical winding directions, which effectively reduce the difficulty of end-wiring and the difficulty of wiring design, and are conducive to the compression of the end space.

[0072] Specifically, as Figure 5 shown, for the reverse winding coil 12, when looking at the coil from bottom to top, the coil adopts a counterclockwise winding method, and the current generally enters from the reverse port 121 and exits from the reverse port 122. The forward winding coil 11 is a mirror-symmetric structure of the reverse winding coil 12. When looking at it from bottom to top, it adopts a clockwise winding method, and the current generally enters from the forward port 111 and exits from the forward port 112. Of course, the actual current flow direction in the coil also depends on the wiring method of the end copper bars and can be completely opposite to the described direction.

[0073] In one example, the entire motor scheme adopts a pole-slot combination structure of 10 poles and 12 slots. Therefore, the entire stator system is equipped with a total of 12 stator iron cores and 12 independent winding coils to be respectively nested into each iron core. However, this topological structure can also be extended to other pole-slot combinations, such as 8 poles and 9 slots, 14 poles and 12 slots, etc. This patent will be described with the 10-pole 12-slot scheme.

[0074] To reduce the wiring difficulty and complexity, the 12 stator windings adopt two winding directions: windings No. 1 to No. 6 adopt reverse windings, and windings No. 7 to No. 12 adopt forward windings. The connection method of the three-phase windings is as follows: Phase U: No. 1 - No. 2 - No. 7 - No. 8; Phase V: No. 3 - No. 4 - No. 9 - No. 10; Phase W: No. 5 - No. 6 - No. 11 - No. 12. To compress the radial space to the greatest extent, the end continuous wave winding or stringing copper bar structure of each phase winding makes space avoidance for the other two phases. At the same time, the short-side wiring method is adopted for the winding ends of the stringing copper bar scheme.

[0075] Specifically, when the end wiring copper bar assembly 2 adopts the stringing copper bar wiring method, only the apex end of the isosceles triangle of the flat wire coil exists in the inner circle of the stator, and the end wiring of the flat wire coil is distributed on the outer circle of the stator winding.

[0076] Specifically, from Figure 6 and Figure 7 it can be seen that the numbers of the flat wire coils and the iron core from 1 to 12 correspond to the winding numbers 1 to 12 in Table 1.

[0077] Table 1

[0078]

[0079] From Figure 6 and Figure 7 the structure, it can be seen that there are short-span copper bars 20 of adjacent windings at the winding ends (the short-span copper bars 20 in Figure 6 and Figure 7 ) and long-span copper bars with the same-phase interval (the long-span copper bars 200 in Figure 6 and Figure 7 ). For the short-span copper bars of the forward winding and the reverse winding, the short-span copper bars of the forward winding and the short-span copper bars of the reverse winding have a mirror symmetry relationship. Similar to the forward and reverse windings, the short-span copper bars of the forward winding only exist in the semi-circle where the forward winding is located and are used for connecting adjacent flat wire coils of each phase of the forward winding; the short-span copper bars of the reverse winding only exist in the semi-circle where the reverse winding is located and are used for connecting adjacent flat wire coils of each phase of the reverse winding. Since the stator winding coil 1 adopts two winding methods of forward and reverse, the long-span copper bars only need to connect the ports on the same side, and the short-span copper bars are greatly simplified.

[0080] The stator system of the present application adopts the way of staggered connection of long-span copper bars and short-span copper bars, which greatly simplifies the complexity of the copper bars. Among them, two adjacent windings of the same phase are connected by short-span copper bars 20, and two windings with the same-phase interval are connected by long-span copper bars 200. The structural dimensions of each short-span copper bar are basically the same, and the structural dimensions of each long-span copper bar are basically the same, which greatly reduces the processing and assembly difficulty and greatly reduces the wiring difficulty. Similarly, such an end wiring copper bar assembly 2 also reduces the axial dimension, which equivalently improves the motor power density and torque density.

[0081] As Figure 4 and Figure 6 shown, further, the end-wiring copper bar assembly further includes a center copper bar 21, short-span copper bars 20 and long-span copper bars 200 that connect adjacent or spaced-apart windings of the same phase; the center copper bar 21 connects three-phase currents after the short-span copper bars 20 and long-span copper bars 200 are connected; that is, the short-span copper bars 20 and long-span copper bars 200 first connect U, V, and W into three parts respectively, and then connect the three parts together through the center copper bar 21. The center copper bar 21, short-span copper bars 20 and long-span copper bars 200 are arranged in a three-layer layout along the axial direction of the stator winding coil 1, and the center copper bar 21 is located in the exact middle (i.e., in the exact middle of the thickness of the stator winding coil 1).

[0082] In the stator system of the present application, the center copper bar 21, short-span copper bars 20 and long-span copper bars 200 are arranged in a three-layer layout along the axial direction of the stator winding coil 1, effectively avoiding mutual interference between the three-phase windings in space. The end envelope of the entire stator system is more compact, the envelope outer diameter is maximally compressed, and the entire structure is more compact, laying a foundation for further improving the power density and torque density.

[0083] In the stator system of the present application, to maximize the compression of the radial space, the end continuous wave winding or series-wiring copper bar structure of each phase winding makes spatial avoidance for the other two phases. At the same time, the series-wiring copper bar scheme adopts a short-side wiring method at the winding end. Considering the process feasibility of the continuous wave winding scheme, the winding end of the continuous wave winding scheme adopts a combination of wide-side wiring and narrow-side wiring. For the part that requires narrow-side wiring, an additional bending process will be added to the winding fold line to achieve the switching between the wide side and the narrow side. The final winding end wiring is divided into three layers in space, including the series wiring between the coil windings of each phase, the three-phase winding star connection copper bar, and the three-phase outgoing line copper bar.

[0084] Further, in one embodiment, the end-wiring copper bar assembly 2 adopts a series-wiring copper bar wiring method or a continuous wave winding wiring method. Whether it is the series-wiring copper bar wiring method or the continuous wave winding wiring method, the form of three-phase connection is the same as Figure 6 similar. When adopting the series-wiring copper bar wiring method, the end-wiring copper bar assembly 2 is independent of the stator winding coil 1; when adopting the continuous wave winding wiring method, the end-wiring copper bar assembly 2 and the stator winding coil 1 are integrated.

[0085] The difference is that when adopting the series-wiring copper bar wiring method, the end-wiring copper bar assembly 2 is as Figure 7As shown, the central copper busbar 21, the short-span copper busbar 20, and the long-span copper busbar 200 are all designed separately from the flat wire coil. For the continuous wave winding wiring method, a structure similar to the short-span copper busbar 20 and the long-span copper busbar 200 directly extends outward from the flat wire coil. That is, the flat wire coil, the short-span copper busbar 20, and the long-span copper busbar 200 of the continuous wave winding wiring method are an integral whole.

[0086] In contrast, for the stator system of the present application, the end-wiring copper busbar assembly 2 adopts the continuous wave winding wiring method, directly winding the port outgoing wire of the corresponding winding coil to the adjacent tooth or the same-phase reverse-wound winding of the other semi-circle, and using the way of winding out with the end of the flat wire copper busbar to extend and replace the short-span copper busbar and the long-span copper busbar of the string-wired copper busbar wiring method. The entire stator winding coil 1 and the end-wiring copper busbar assembly 2 are of an integral structure, and the three-phase outgoing copper busbars are also directly connected from the port outgoing wires of the corresponding windings. This connection method greatly reduces the number of solder joints and has stronger structural stability.

[0087] Furthermore, considering the process feasibility of winding with the continuous wave winding scheme, the winding end of the continuous wave winding scheme adopts a combination of wide-side wiring and narrow-side wiring. For the part that requires narrow-side wiring, an additional bending process will be added to the winding fold line to achieve the switching between the wide side and the narrow side.

[0088] Specifically, the connection method of the three-phase windings is as follows. Whether it is the string-wired copper busbar wiring method or the continuous wave winding wiring method, the current flow direction is as follows:

[0089] As Figures 6 to 11 shown, for the U phase: The current enters from the U-phase outgoing copper busbar in Figure 6 through the reverse one-port 121 of the No. 1 reverse-wound winding, exits from the reverse two-port 122, enters the reverse two-port 122 of the No. 2 reverse-wound winding through the adjacent tooth short-span copper busbar 20 (separate string-wired short-span copper busbar or integral wave-wound short-span copper busbar 211), exits from the reverse one-port 121 of the No. 2 reverse-wound winding, and reaches the positive one-port 111 of the U-phase No. 7 forward-wound winding in the other semi-circle of the motor through the U-phase long-span copper busbar 200 (separate string-wired long-span copper busbar or integral wave-wound long-span copper busbar 212). It exits from the positive two-port 112 of the No. 7 forward-wound winding, enters the positive two-port 112 of the No. 8 forward-wound winding through the adjacent tooth short-span copper busbar 20, and finally exits from the positive one-port 111 of the No. 8 forward-wound winding and enters the other two phases through the central copper busbar 21.

[0090] For the V phase: The current enters from Figure 6The copper bar of the V-phase outgoing line in it enters the anti-two-port 122 of the No. 3 anti-wound winding, exits from the anti-one-port 121, enters the anti-one-port 121 of the No. 4 anti-wound winding through the adjacent tooth short-span copper bar 20 (separated series-wired short-span copper bar or integral wave-wound short-wound copper bar 211), exits from the anti-two-port 122 of the No. 4 anti-wound winding, and reaches the positive two-port 112 of the V-phase No. 9 positive-wound winding in the other half of the motor through the V-phase long-span copper bar 200 (separated series-wired long-span copper bar or integral wave-wound long-wound copper bar 212). It exits from the positive one-port 111 of the No. 9 positive-wound winding, enters the positive one-port 111 of the No. 10 positive-wound winding through the adjacent tooth short-span copper bar 20, and finally exits from the positive two-port 112 of the No. 10 positive-wound winding and enters the central copper bar 21.

[0091] W-phase: The current flows from Figure 6 The copper bar of the W-phase outgoing line in it enters the anti-one-port 121 of the No. 5 anti-wound winding, exits from the anti-two-port 122, enters the anti-two-port 122 of the No. 6 anti-wound winding through the adjacent tooth short-span copper bar 20, exits from the anti-one-port 121 of the No. 6 anti-wound winding, and reaches the positive one-port 111 of the W-phase No. 11 positive-wound winding in the other half of the motor through the W-phase long-span copper bar 200. It exits from the positive two-port 112 of the No. 11 positive-wound winding, enters the positive two-port 112 of the No. 12 positive-wound winding through the adjacent tooth short-span copper bar 20, and finally exits from the positive one-port 111 of the No. 12 positive-wound winding and enters the central copper bar 21.

[0092] Specifically, as Figures 8 to 11 shown, for the continuous wave-wound wiring method, for the U-phase, Figure 9 the end wiring between adjacent windings in it is connected by the wave-wound short-span copper bar 211 (see Figure 9 ), the copper bar of the U-phase outgoing line adopts the phase outgoing copper bar 213 as in Figure 9 , and the spaced U-phase windings are connected by the wave-wound long-span copper bar 212, and the wave-wound long-span copper bar 212 adopts the short-side wiring method.

[0093] For the V-phase, the adjacent windings are connected by Figure 10 the wave-wound short-span copper bar 211 in it, the copper bar of the V-phase outgoing line adopts the phase outgoing copper bar 213 as in Figure 10 , in order to minimize the outer diameter of the stator as much as possible, reduce the volume of the motor, and improve the torque and power density, the wave-wound long-span copper bar 212 of the V-phase adopts the wide-side wiring method and has two bending feature treatments to avoid the end wiring of the other two phases. Figure 10 The V-phase outgoing line in Figure 10 i.e., the phase outgoing copper bar 213 in

[0094] Figure 11 is also bent to avoid the wiring of the other two phases here. Figure 11The waves in it are connected by the short-span copper bars 211, and the spaced W-phase windings are connected by Figure 11 the long-span copper bars 212 in it. The phase outlet copper bar 213 of the W phase is directly bent out.

[0095] For the stator system of this application, when the continuous wave winding method is used, the number of end solder joints of the entire stator winding is greatly reduced. Each phase winding can be directly wound by continuously bending a single-strand copper wire without the need for end copper bar welding connections. Only three solder joints of the central copper bar are retained in the entire stator winding to connect the three-phase wave windings.

[0096] Further, in an embodiment, when n is equal to 2, the winding numbers are sequentially 1 to 12 in the counterclockwise direction, and the phases to which the 1 to 12 windings belong and the positive and negative directions of the current are sequentially U+, U-, V-, V+, W+, W-, U-, U+, V+, V-, W- and W+.

[0097] In an embodiment, the iron core unit 31 is made of a soft magnetic composite material by pressing.

[0098] Specifically, the full name of the soft magnetic composite material SMC is soft magnetic composite material; the soft magnetic composite material is a composite material composed of magnetic powder and polymer resin, and has the advantages of magnetic isotropy, high magnetic permeability, low coercivity, high Curie temperature, and low loss. The iron core unit 31 formed by pressing the soft magnetic composite material, together with the non-back yoke segmented iron core group, has a lighter overall weight, less material consumption, can reduce the occupied volume, and has a compact structure.

[0099] In the description of this application, it should be noted that the orientation or positional relationship indicated by terms such as "upper" and "lower" is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing this application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, so it cannot be understood as a limitation to this application. Unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific situations.

[0100] It should be noted that in this application, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, article or device comprising the element.

[0101] The above are only specific embodiments of the present application, enabling those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but rather to the broadest scope consistent with the principles and novel features claimed herein.

Claims

1. A stator system of an axial flux motor, characterized in that: The stator system adopts a three-phase symmetrical topology structure, which includes: The stator winding coil (1) comprises a plurality of flat wire coils which are flat in the axial direction, each coil being in the shape of an isosceles triangle, the two bottom forming angles of the isosceles triangle being greater than 60°, and the bending radius during the forming process of the flat wire coil is less than one time of the wire width; The end wiring copper bar assembly (2) is used to connect the flat wire coil of the stator winding coil (1) according to the three-phase symmetrical topological structure, and lead out the three-phase soft copper wire (22) connected to the outside; A segmented stator core group (3) without a back yoke comprises a plurality of core units (31), each core unit (31) being independently arranged at intervals, a fully open slot design being adopted between two adjacent core units (31), and the flat wire coils of the stator winding coils (1) and the core units (31) of the segmented stator core group (3) being nested one by one to form a winding.

2. The stator system of an axial flux motor according to claim 1, characterized in that: After the flat wire coil of the stator winding coil (1) with the end wiring copper bar assembly (2) is nested in the segmented stator core group (3), it is dipped in glue to form an overall dipped in glue structure; and the overall dipped in glue structure has reserved connection holes for the three-phase soft copper wire (22) to facilitate connection.

3. The stator system of an axial flux motor according to claim 2, characterized in that : There is a set gap between the layers of the flat wire coil, and when the dipping process is carried out, the set gap is filled with an insulating glue layer.

4. The stator system of an axial flux motor according to claim 1, characterized in that: The radii of the three inner fillets of the flat wire coil are all the same, and the radii of the inner fillets are all smaller than the width of the flat wire.

5. The stator system of an axial flux motor according to claim 1, characterized in that: The end wiring copper bar assembly (2) adopts a series copper bar wiring method or a continuous band wiring method to connect multiple windings.

6. The stator system of an axial flux motor according to claim 1, characterized in that: The stator system comprises 3(2n+2) windings, which are divided into 3(n+1) positive windings and 3(n+1) reverse windings, where n is a positive integer greater than or equal to 1; The end wiring copper bar assembly comprises a plurality of short-span copper bars (20) and a plurality of long-span copper bars (200), and all windings are symmetrical about the center in positive and negative directions; The adjacent windings of the same phase of 3 (n+1) positive windings or 3 (n+1) reverse windings are connected via a short-span copper bar (20); the long-span copper bar (200) connects the windings of the same phase at intervals.

7. The stator system of an axial flux motor according to claim 6, characterized in that: The end wiring copper bar assembly further comprises a central copper bar (21), wherein the short-span copper bar (20) and the long-span copper bar (200) are connected to adjacent or spaced windings of the same phase; the central copper bar (21) is connected to the three-phase current after the short-span copper bar (20) and the long-span copper bar (200) are connected; the central copper bar (21), the short-span copper bar (20) and the long-span copper bar (200) are arranged in a three-layer layout and spaced apart along the axial direction of the stator winding coil (1), and the central copper bar (21) is located in the middle.

8. The stator system of an axial flux motor according to claim 1, characterized in that: The end wiring copper bar assembly (2) adopts a series copper bar routing method or a continuous wave winding routing method. When the series copper bar routing method is adopted, the end wiring copper bar assembly (2) is independent of the stator winding coil (1); when the continuous wave winding method is adopted, the end wiring copper bar assembly (2) and the stator winding coil (1) are integrated.

9. The stator system of an axial flux motor according to claim 6, characterized in that: When n is equal to 2, the winding numbers are 1 to 12 in counterclockwise order, and the phases to which windings 1 to 12 belong and the positive and negative directions of the current are U+, U-, V-, V+, W+, W-, U-, U+, V+, V-, W- and W+ respectively.

10. The stator system of an axial flux motor according to claim 1, characterized in that: The iron core unit (31) is formed by pressing a soft magnetic composite material.

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