A stator system of an axial flux motor

Abstract

The application relates to a stator system of an axial flux motor, in particular to a new energy automobile driving motor technology field, a stator winding coil, containing a plurality of flat wire coils, each coil being isosceles triangle, the two base forming angles of the isosceles triangle are both greater than 60 DEG, and the bending radius in the forming process of the flat wire coil is less than one times the wire width; an end wire copper bar assembly is used for connecting the flat wire coil; a segmented stator core group without a back yoke contains a plurality of core units, each core unit is independently and separately arranged, full-open slot design is adopted between the two adjacent core units, the flat wire coil of the stator winding coil is nested with the core units of the segmented stator core group to form a winding. The stator system of the axial flux motor adopts the segmented stator core group with the full-open slot yokeless structure, the stator winding coil is nested in the core by adopting the flat vertical winding method, the axial structure is more compact, and the motor power density and torque density are greatly improved.

Description

Technical Field

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

[0002] With the growing popularity of concepts like distributed systems and wheel-end drives, axial-flux motors have become a research hotspot due to their compact size and high torque and power densities. Due to the significant axial attraction between the stator and rotor of axial-flux motors, the new energy vehicle motor industry often uses a symmetrical stator-rotor disc topology to offset the axial forces of the entire motor, thereby increasing the stability of the shaft system and electric drive system. Compared to radial motors at the same performance level, axial motors can more than double the torque density, reduce the axial dimension by over 50%, and reduce the weight to less than one-third of the original. This allows for a more compact motor and assembly structure, reducing vehicle mass and increasing range.

[0003] In the related technologies, the mainstream axial flux motor topology in the new energy industry is divided into single stator and dual rotor. The structure of single stator is similar to Figure 1 In the structure shown, the yoke a is annular, with stator teeth b protruding from the yoke a's surface axially. Multiple stator teeth b are spaced circumferentially around the yoke a and form winding slots c. The ends of the stator teeth b facing away from the yoke a are provided with flanges d extending along the width of the stator teeth b. Stator winding coils are wound around the stator teeth b.

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

[0005] The present application provides a stator system for an axial flux motor, which adopts a segmented stator core group with a fully open slot and yokeless structure. The stator winding coils are nested in the core using a flat wire vertical winding method. The axial structure is more compact, which greatly improves the power density and torque density of the motor.

[0006] The present application discloses a stator system for an axial flux motor, wherein the stator system adopts a three-phase symmetrical topology and comprises: a stator winding coil, comprising a plurality of axially flattened flat wire coils, each coil being an isosceles triangle, wherein both base forming angles of the isosceles triangle are greater than 60°, and the bending radius of the flat wire coil during the forming process is less than one time of the wire width;

[0007] The end wiring copper bar assembly is used for connecting the flat coil of the stator winding coil in a three-phase symmetrical topology, and leads out three-phase soft copper wires connected with the outside.

[0008] The segmented stator core group without a back yoke comprises a plurality of core units, each of which is independently and separately arranged, and an all-open slot design is adopted between adjacent two core units, and the flat coil of the stator winding coil is nested with the core units of the segmented stator core group to form a winding.

[0009] On the basis of the above technical scheme, after the flat coil of the stator winding coil of the end wiring copper bar assembly is nested in the segmented stator core group, a dipping treatment is performed to form an overall dipping structure, and the overall dipping structure is provided with connecting holes for facilitating connection of the three-phase soft copper wires.

[0010] On the basis of the above technical scheme, the flat coil layers have a set gap, and the set gap is filled with an insulating glue layer during the dipping treatment.

[0011] On the basis of the above technical scheme, the radii of the three inner fillets of the flat coil are the same, and the radii of the inner fillets are smaller than the flat coil width.

[0012] On the basis of the above technical scheme, the end wiring copper bar assembly adopts a series copper bar wiring mode or a continuous wave band wiring mode to connect a plurality of windings.

[0013] On the basis of the above technical scheme, the stator system comprises 3(2n+2) windings, which are divided into 3(n+1) positive windings and 3(n+1) negative windings, wherein 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 and a plurality of long-span copper bars, and all the windings are symmetrically arranged in the center; the same-phase adjacent windings of the 3(n+1) positive windings or the 3(n+1) negative windings are connected by the short-span copper bars; and the long-span copper bars connect the windings of the same phase at intervals.

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

[0015] On the basis of the above technical scheme, the end wiring copper bar assembly adopts a series copper bar wiring mode or a continuous wave winding wiring mode, when the series copper bar wiring mode is adopted, the end wiring copper bar assembly is independent of the stator winding coil; and when the continuous wave winding wiring mode is adopted, the end wiring copper bar assembly is integrated with the stator winding coil.

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

[0017] On the basis of the above technical solution, the iron core unit is pressed by using soft magnetic composite material.

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

[0019] 1. The stator system of the present application is uniquely designed. In the first aspect, the stator winding coil is replaced by a flat wire coil along the axial direction instead of the traditional circular wire scheme in the axial motor, so that a non-metallic skeleton for fixing the circular wire in the slot is not needed, the structure is simplified, and the axial size is greatly reduced compared with the circular wire coil, so that the structure is more compact. Further, each flat wire coil is an isosceles triangle, the top forming angle of the isosceles triangle is close to the inner circle side of the stator, the two bottom forming angles are close to the outer circle side of the stator, and the two bottom forming angles are greater than 60° (the corresponding bottom bending angle is greater than 90°). The top forming angle is less than 60° (the corresponding top bending angle is greater than 120°), and the bending radius in the forming process of the flat wire coil is less than one times the wire width. Each flat wire coil is processed by a pre-forming method to directly process the final shape and the fillet size 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 along the radial direction as much as possible, and reduce the axial size. In the second aspect, the segmented stator core group adopts a no-back-yoke design, the overall weight is lighter, and the material is less. At the same time, the no-back-yoke design leaves the thickness size of the original yoke part, the overall axial size is small, and the structure is more compact. In the third aspect, a full-open slot design is adopted between the two adjacent iron core units, which can make the wire embedding more convenient and more process feasible. Compared with the traditional design of the stator core axial end face with a flange d, the segmented stator core group adopts a full-open slot design, which greatly reduces the difficulty of wire embedding.

[0020] 2. After the flat wire coil of the stator winding coil with the end line copper bar assembly is nested in the segmented stator core group, the stator system of the present application is subjected to a dipping treatment to form an overall dipping structure, so that the overall structure is stable and reliable.

[0021] 3. The stator system of the present application, the flat wire coil reduces the processing difficulty by using a larger set gap between layers, and enhances the insulation and heat conduction performance; Specifically, due to the high difficulty of the design process of the large bending angle of the flat wire coil, there is also a large extrusion deformation in the inner side of the flat copper wire bending part, therefore the interlayer gap of the flat wire coil is adjusted for the design of the large bending angle, a larger interlayer set gap is used, and the winding film material also uses a material with ductility and good adhesion; The overall impregnation treatment, the gap between the winding layers will be filled with insulating glue, and the insulation performance, heat conduction performance and overall strength will be greatly improved.

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

[0023] 5. The stator system of the present application adopts the mode of long-span copper bars and short-span copper bars interlaced connection, which greatly simplifies the complexity of the copper bars, wherein the two adjacent windings of the same phase are connected by the short-span copper bars, and the two windings separated by two windings of the same phase are connected by the long-span copper bars, the structure size of each short-span copper bar is basically the same, the structure size of each long-span copper bar is basically the same, which greatly reduces the processing and assembly difficulty, greatly reduces the wiring difficulty, and the same end wiring copper bar assembly also reduces the axial size, which is equivalent to improving the motor power density and torque density.

[0024] 6. The stator system of the present application, the center copper bar, the short-span copper bar and the long-span copper bar are arranged in three layers along the axial direction of the stator winding coil, which effectively avoids the mutual interference of the three-phase windings in space, the end envelope of the whole stator system is more compact, the envelope outer diameter is compressed to the maximum, and the whole structure is more compact, which lays a foundation for further improving the power density and torque density. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creating laborious work.

[0026] Figure 1 The structure diagram of the yoke and the stator tooth in the prior art;

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

[0028] Figure 3A schematic view of the assembled stator system provided by the embodiment of the present application;

[0029] Figure 4 A left view of the embodiment of the present application; Figure 3

[0030] Figure 5 A structure schematic view of the positive winding coil and the reverse winding coil provided by the embodiment of the present application;

[0031] Figure 6 A connection schematic view of the connection of the stator winding coil through the end wire copper bar assembly provided by the embodiment of the present application;

[0032] Figure 7 A structure schematic view of the end wire copper bar assembly using the series wire copper bar wire arrangement provided by the embodiment of the present application;

[0033] Figure 8 A structure schematic view of the stator winding coil using the continuous wave winding wire arrangement provided by the embodiment of the present application;

[0034] Figure 9 A schematic view of the short span, the long span and the outgoing copper bar of the U phase of the continuous wave winding wire arrangement provided by the embodiment of the present application;

[0035] Figure 10 A schematic view of the short span, the long span and the outgoing copper bar of the V phase of the continuous wave winding wire arrangement provided by the embodiment of the present application;

[0036] Figure 11 A schematic view of the short span, the long span and the outgoing copper bar of the W phase of the continuous wave winding wire arrangement 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, positive winding coil; 12, reverse winding coil;

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

[0040] 111, positive one port; 112, positive two port;

[0041] 2, end wire 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 winding short span copper bar; 212, wave winding long span copper bar; 213, phase outgoing copper bar;

[0044] 3, segmented stator core group; 31, core unit. ​DETAILED DESCRIPTION

[0045] In order to make the person skilled in the art better understand the scheme of the present application, the technical scheme in the embodiments of the present application will be clearly and completely described below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by the person skilled in the art without creative labor fall within the scope of protection of the present application.

[0046] The stator system of the axial flux motor provided in the embodiments of the present application breaks through the existing torque density and power density of the axial flux motor on the market by designing a brand-new stator system, and can improve more than 40% through experimental verification.

[0047] Specifically, when designing initially, a distributed electric drive assembly with a peak torque ≥ 8500 Nm and a peak power ≥ 450 kW is designed within a space range with an outer envelope size not exceeding 480 mm x 530 mm x 400 mm. The corresponding axial flux motor has a peak torque density ≥ 28 Nm / kg, a power density ≥ 10 kW / kg, and a motor axial size ≤ 100 mm. However, if a single stator structure such as shown in Figure 1 is used for design, the performance indicators of the design target cannot be reached, so the axial size of the stator system needs to be as small as possible and the structure needs to be as compact as possible. After the stator system of the present application is used, the performance indicators of the above design target are successfully achieved, breaking through the existing torque density and power density of the axial flux motor on the market, and can improve more than 40% through experimental verification.

[0048] Further, in order to make the axial size of the stator system as compact as possible, the stator core of the axial flux motor of the present application adopts a segmented stator core group with a full-open slot and a yoke-free structure, and the stator winding coil adopts a flat wire vertical winding method and is nested in the core, so that the axial structure is more compact and the power density and torque density of the motor are greatly improved.

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

[0050] The stator winding coil 1 includes a plurality of axial flat wire coils, each flat wire coil is in the shape of an isosceles triangle, the top forming angle of the isosceles triangle is close to the inner circle side of the stator, the two bottom forming angles are close to the outer circle side of the stator, and the two bottom forming angles are both greater than 60° but less than 90° (the corresponding bottom bending angle is greater than 90°), and the bending radius in the forming process of the flat wire coil is less than one times the wire width.

[0051] The stator winding coil 1 of the present application adopts an axially flat flat wire coil to replace the round wire scheme in the traditional axial motor, so it is not necessary to install a non-metallic skeleton for fixing the round wire in the slot, which simplifies the structure, and at the same time, the axial size of the flat wire coil is greatly reduced compared with the round wire coil, making the structure more compact. Further, each flat wire coil is an isosceles triangle, 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 the two bottom forming angles are both greater than 60° but less than 90°, and the bending radius in the forming process of the flat wire coil is less than one times the wire width, each flat wire coil is pre-formed, and the final shape and fillet size are directly processed by the 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 the single core unit 31, spread out as much as possible in the radial direction, and at the same time reduce the axial size.

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

[0053] The end wire copper bar assembly 2 is used to connect the flat wire coils of the stator winding coil 1 according to a three-phase symmetrical topology, and lead out three-phase soft copper wires 22 connected to the outside.

[0054] The segmented stator core group 3 adopts a rear yoke-free design, that is, the yoke part a in Figure 1 , which reduces the axial size, and the segmented stator core group 3 includes a plurality of core units 31, each of which is independently and separately arranged, and the two adjacent core units 31 adopt a full-open slot design, that is, the core unit 31 is in the flange d structure in Figure 1 , the winding slot c formed between the two adjacent core units 31 is not limited by the flange d, and the flat wire coils of the stator winding coil 1 are one-to-one nested with the core units 31 of the segmented stator core group 3 to form windings, that is, each winding is formed by winding the core unit 31 with the flat wire coil.

[0055] Specifically, the core unit 31 is also an isosceles triangle, and the shape and size of the core unit 31 are matched with the shape and size in 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 an axially flat flat wire coil to replace the round wire scheme in the traditional axial motor, so it is not necessary to install a non-metallic skeleton for fixing the round wire in the slot, which simplifies the structure, and at the same time, the axial size of the flat wire coil is greatly reduced compared with the round wire coil, so that the structure is more compact. Further, each flat wire coil is in the shape of an isosceles triangle, 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 the two bottom forming angles are greater than 60° but less than 90° (the corresponding bottom bending angle is greater than 90°), and the top forming angle is less than 60° (the corresponding top bending angle is greater than 120°), and the bending radius in the forming process of the flat wire coil is less than one times the wire width, and each flat wire coil is pre-formed, and the final shape and the round corner size are directly processed by the 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 the single core unit 31, spread out as much as possible in the radial direction, and at the same time reduce the axial size. In the second aspect, the segmented stator core group 3 adopts a no-back-yoke design, which is lighter in weight and uses less material, and at the same time, the no-back-yoke design leaves the original yoke thickness size, the overall axial size is small, and the structure is more compact. In the third aspect, the full open slot design is adopted between the two adjacent core units 31, which can make the wire embedding more convenient and more process feasible. Compared with the traditional stator core axial end face with flange d design, the segmented stator core group 3 adopts the full open slot design, which greatly reduces the difficulty of wire embedding.

[0057] Further, in one embodiment, after the flat wire coil of the stator winding coil 1 of the end portion wire copper bar assembly 2 is embedded in the segmented stator core group 3, a dipping process is performed to form an overall dipping structure; and the overall dipping structure is provided with a connection hole for connecting the three-phase soft copper wire 22.

[0058] Specifically, in the wire copper bar wire arrangement mode, the end portion wire copper bar assembly 2 as shown in Figure 7 is connected to the stator winding coil 1, and then the segmented stator core group 3 is nested, and then the dipping process is performed. Among them, the end portion wire copper bar assembly 2 is connected to the stator winding coil 1, and a wire arrangement relationship is formed in Figure 6 .

[0059] Specifically, the core unit 31 of the segmented stator core group 3 will be nested with the flat wire coil of the stator winding coil 1 one by one, and the effect after the nesting is completed is as shown in Figure 3 . Then the dipping process is performed, and the gap between the stator winding coil 1 and the segmented stator core group 3, and the interlayer gap inside the stator winding coil 1 are filled, so that the strength and rigidity of the overall dipping structure are improved; the stator winding coil 1 and the segmented stator core group 3 after dipping and curing are connected with the three-phase soft copper wire 22.

[0060] The stator system of the present application, after the flat wire coil of the stator winding coil 1 of the end-wiring copper bar assembly 2 is nested in the segmented stator core group 3, the impregnation treatment is carried out to form a whole impregnation structure, so that the whole structure is stable and reliable.

[0061] As shown in Figure 5 Further, each flat wire coil itself has a set gap between layers, and the set gap is filled with an insulating glue layer during impregnation treatment.

[0062] The stator system of the present application, by using a larger set gap between layers, reduces the processing difficulty and enhances the insulation and heat conduction performance; specifically, due to the high difficulty of the design process of the large bending angle of the flat wire coil (the bottom bending angle is greater than 90°, and the top bending angle is greater than 120°), there is also a large extrusion deformation inside the flat copper wire bending part, therefore the interlayer gap of the flat wire coil is adjusted for the large bending angle design, a larger interlayer set gap is adopted, and the winding varnish material also adopts a material with ductility and good adhesion; the whole impregnation treatment, the gap between the winding layers will be filled with insulating glue, and the insulation performance, heat conduction performance and overall strength will be greatly improved.

[0063] Further, in order to reduce the difficulty of winding processing, the top angle and the bottom edge of the isosceles triangle of the flat wire coil and the core unit 31 are not treated with a circular arc to match the shape of the rotor disc, but a straight line design method is adopted, which greatly reduces the processing difficulty.

[0064] In one embodiment, the radii of the three inner fillets of the flat wire coil are the same, which reduces the processing difficulty, and all the radii are less than one time the flat wire width, which maximizes the radial spreading area and reduces the axial size. Specifically, although the radii of the three inner fillets of the flat wire coil are the same, the bending radii are different, and the bending radius of the top angle is greater than that of the other two angles.

[0065] The sizes of the two fillets of the bottom edge of the isosceles triangle core unit 31 are the same as those of the flat wire coil, so as to achieve the best fitting effect.

[0066] The stator system of the present application, the radii of the three inner fillets of the flat wire coil are the same, which can greatly reduce the processing difficulty, and all the radii are less than one time the flat wire width, which can maximize the radial spreading area and further reduce the axial size, so that the overall axial size of the stator structure is greatly reduced, and the power density and torque density are improved.

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

[0068] Specifically, the connection relationship of the two wiring methods is as shown in Figure 6The end wiring copper bar assembly 2 of the two wiring modes is different in structure, but both wiring modes can ensure that the stator system forms a three-phase symmetric topology.

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

[0070] Among them, the end wiring copper bar assembly includes a plurality of short-span copper bars 20 and a plurality of long-span copper bars 200, and all the windings are symmetrically arranged in the center (see Figure 3 The same-phase adjacent windings of the 3(n+1) positive windings or the 3(n+1) negative windings are connected by the short-span copper bar 20, for example Figure 3 The short-span copper bar 20 in 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 The long-span copper bar 200 in connects the windings of No. 2 and No. 7 at intervals.

[0071] The stator system of the present application adopts two kinds of vertical winding directions, which effectively reduces the difficulty of end wiring and wiring design, and is beneficial to the compression of the end space.

[0072] Specifically, as Figure 5 shown, the negative coil 12 is wound counterclockwise from bottom to top, and the current generally enters from the negative one port 121 and exits from the negative two port 122. The positive coil 11 is a mirror-symmetric structure of the negative coil 12, and is wound clockwise from bottom to top, and the current generally enters from the positive one port 111 and exits from the positive two port 112. Of course, the current direction in the actual coil also depends on the wiring mode of the end copper bar, which can be completely opposite to the described direction.

[0073] In one example, the entire motor scheme adopts a 10-pole 12-slot pole-slot matching structure, so the entire stator system is provided with 12 stator cores and 12 independent winding coils to be respectively nested in each core. However, this kind of topology structure can also be expanded to other pole-slot matching structures, such as 8-pole 9-slot, 14-pole 12-slot, etc. The present patent is described based on the 10-pole 12-slot scheme.

[0074] In order to reduce the wiring difficulty and complexity, the 12 stator windings adopt two winding directions: the 1-6 windings adopt reverse winding, and the 7-12 windings adopt positive winding. The three-phase winding connection mode is: U phase: 1-2-7-8; V phase: 3-4-9-10; W phase: 5-6-11-12. In order to compress the radial space to the maximum extent, the continuous wave winding or the string copper bar structure of each phase winding end continuously avoids the space of the other two phases, and the string copper bar scheme winding end adopts the short side wiring mode.

[0075] Specifically, when the end wiring copper bar assembly 2 adopts the string copper bar wiring mode, only the top angle 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 the Figure 6 and Figure 7 corresponding to the winding numbers 1-12 in Table 1.

[0077] Table 1

[0078]

[0079] From the Figure 6 and Figure 7 structure, it can be seen that the winding end exists adjacent winding short span copper bar 20 ( Figure 6 and Figure 7 short span copper bar 20) and same phase interval long span copper bar ( Figure 6 and Figure 7 long span copper bar 200), for the short span copper bar of positive winding and reverse winding, the short span copper bar of positive winding and the short span copper bar of reverse winding exist mirror symmetry relationship, similar to positive and reverse winding, the short span copper bar of positive winding only exists in the semicircle where the positive winding is located, and is used for the series connection of adjacent flat wire coils of each phase positive winding. The short span copper bar of the reverse winding only exists in the semicircle where the reverse winding is located, and is used for the series connection of adjacent flat wire coils of each phase reverse winding. Since the stator winding coil 1 adopts positive and reverse winding modes, the long span copper bar only needs to connect the same side port, and the short span copper bar is greatly simplified.

[0080] The stator system of the present application adopts the long span copper bar and short span copper bar staggered connection mode, which greatly simplifies the complexity of the copper bar, wherein the same phase adjacent two windings are connected through the short span copper bar 20, and the same phase interval two windings are connected through the long span copper bar 200. The structure size of each short span copper bar is basically the same, and the structure size of each long span copper bar is basically the same, which greatly reduces the processing and assembly difficulty, greatly reduces the wiring difficulty, and also reduces the axial size of the end wiring copper bar assembly 2, which increases the motor power density and torque density.

[0081] As shown in Figure 4 and Figure 6 Further, the end wire copper bar assembly also includes a center copper bar 21, a short span copper bar 20 and a long span copper bar 200 connecting the adjacent or spaced same phase windings; the center copper bar 21 connects the three-phase current after the short span copper bar 20 and the long span copper bar 200 are connected; that is, the short span copper bar 20 and the long span copper bar 200 first connect U, V, and W into three parts, and then connect the three parts together through the center copper bar 21. The center copper bar 21, the short span copper bar 20 and the long span copper bar 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 at the center (i.e., at the center of the thickness of the stator winding coil 1).

[0082] The stator system of the present application, the center copper bar 21, the short span copper bar 20 and the long span copper bar 200 are arranged in a three-layer layout along the axial direction of the stator winding coil 1, effectively avoiding mutual interference of the three-phase windings in space, the end envelope of the entire stator system is more compact, the envelope outer 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.

[0083] The stator system of the present application, for maximum compression of the radial space, each phase winding end continuous wave winding or series wire copper bar structure is space-avoided for the other two phases, and the winding end of the series wire copper bar scheme adopts a short side wire layout. Considering the process realizability of the continuous wave winding scheme, the winding end of the continuous wave winding scheme adopts a combination of wide side wire layout and narrow side wire layout. For the part that needs narrow side wire layout, an additional bending process is added to the winding fold line to realize the switching of wide side and narrow side. The final winding end wire space is divided into three layers in total, including series wire between each phase winding coil, three-phase winding star connection copper bar, and three-phase outgoing copper bar.

[0084] Further, in one embodiment, the end wire copper bar assembly 2 adopts a series wire copper bar wire layout or a continuous wave winding layout. Regardless of the series wire copper bar wire layout or the continuous wave winding layout, the three-phase connection form is similar to Figure 6 When the series wire copper bar wire layout is adopted, the end wire copper bar assembly 2 is independent of the stator winding coil 1; when the continuous wave winding layout is adopted, the end wire copper bar assembly 2 is integrated with the stator winding coil 1.

[0085] The difference lies in that when the series wire copper bar wire layout is adopted, the end wire copper bar assembly 2 is as shown in Figure 7As shown, the center copper busbar 21, short-span copper busbar 20, and long-span copper busbar 200 are designed separately from the flat wire coil. In contrast, the continuous wave routing method directly extends outward from the flat wire coil to form a structure similar to the short-span copper busbar 20 and long-span copper busbar 200. In other words, the flat wire coil, short-span copper busbar 20, and long-span copper busbar 200 in the continuous wave routing method are integrated.

[0086] In comparison, in the stator system of the present application, the end wiring copper bar assembly 2 adopts a continuous wave winding method, and the port outlet wires of the corresponding winding coils are directly wound around the adjacent teeth or the same-phase opposite windings of the other semicircle. The short-span copper bars and long-span copper bars of the string copper bar wiring method are extended by the end winding of the flat wire copper bar to replace the short-span copper bars and long-span copper bars of the string copper bar wiring method. The entire stator winding coil 1 and the end wiring copper bar assembly 2 are an integrated structure, and the three-phase outlet copper bars are also directly connected to the port outlet wires of the corresponding windings. This connection method greatly reduces the number of solder joints and has a stronger structural stability.

[0087] Furthermore, 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 routing and narrow-side routing. For the part that requires narrow-side routing, an additional bending process will be added to the winding fold line to realize the switching between wide and narrow sides.

[0088] Specifically, the three-phase winding connection method is as follows. Regardless of whether the copper busbar wiring method or the continuous wave wiring method is used, the current flow is as follows:

[0089] like Figures 6 to 11 As shown, U phase: current from Figure 6 The U-phase outgoing copper bar enters through the anti-first port 121 of the No. 1 anti-winding winding, exits from the anti-second port 122, passes through the adjacent tooth short-span copper bar 20 (a separate series short-span copper bar or an integrated wave-wound short-span copper bar 211), enters the anti-second port 122 of the No. 2 anti-winding winding, exits from the anti-first port 121 of the No. 2 anti-winding winding, passes through the U-phase long-span copper bar 200 (a separate series long-span copper bar or an integrated wave-wound long-span copper bar 212), and reaches the positive first port 111 of the U-phase No. 7 positive winding of the other semicircle of the motor, exits from the positive second port 112 of the No. 7 positive winding, passes through the adjacent tooth short-span copper bar 20, enters the positive second port 112 of the No. 8 positive winding, and finally exits through the positive first port 111 of the No. 8 positive winding, and enters the other two phases through the center copper bar 21.

[0090] V phase: current from Figure 6The V-phase outgoing copper bar enters the anti-second port 122 of the No. 3 counter-winding winding, exits from the anti-first port 121, passes through the adjacent tooth short-span copper bar 20 (a separate series short-span copper bar or an integrated wave-wound short-span copper bar 211), enters the anti-first port 121 of the No. 4 counter-winding winding, exits from the anti-second port 122 of the No. 4 counter-winding winding, passes through the V-phase long-span copper bar 200 (a separate series long-span copper bar or an integrated wave-wound long-span copper bar 212), reaches the positive second port 112 of the V-phase No. 9 positive winding of the other semicircle of the motor, exits from the positive first port 111 of the No. 9 positive winding, passes through the adjacent tooth short-span copper bar 20, enters the positive first port 111 of the No. 10 positive winding, and finally passes through the positive second port 112 of the No. 10 positive winding to enter the center copper bar 21.

[0091] W phase: current from Figure 6 The W-phase outgoing copper busbar enters the anti-first port 121 of the No. 5 counter-winding winding, exits from the anti-second port 122, enters the anti-second port 122 of the No. 6 counter-winding winding through the adjacent tooth short-span copper busbar 20, exits from the anti-first port 121 of the No. 6 counter-winding winding, passes through the W-phase long-span copper busbar 200 to reach the positive first port 111 of the W-phase No. 11 positive winding of the other semicircle of the motor, exits from the positive second port 112 of the No. 11 positive winding, passes through the adjacent tooth short-span copper busbar 20 to enter the positive second port 112 of the No. 12 positive winding, and finally exits through the positive first port 111 of the No. 12 positive winding and enters the center copper busbar 21.

[0092] Specifically, if Figures 8 to 11 As shown, the continuous wave routing method, for the U phase, Figure 9 The ends of the adjacent windings are connected by a short-span copper bus 211 (see Figure 9 ), the U-phase outgoing copper busbar adopts Figure 9 The phase outgoing copper bar 213 and the interval U-phase winding are connected through the wave-wound long-span copper bar 212, and the wave-wound long-span copper bar 212 adopts the short-side routing method.

[0093] For V phase, adjacent windings are connected by Figure 10 The short-span copper busbar 211 in the wave winding is connected, and the V-phase outgoing copper busbar adopts the following Figure 10 In order to minimize the outer diameter of the stator, reduce the volume of the motor, and improve the torque and power density, the phase outgoing copper bar 213 in the V-phase wave winding long span copper bar 212 adopts a wide side routing method and is processed with two bending features to avoid the end routing of the other two phases. Figure 10 The V phase outgoing line is Figure 10 The phase outgoing copper bus 213 is also bent to avoid the routing of the other two phases.

[0094] Figure 11 The wave winding method of the W phase winding is shown. The adjacent windings of the W phase are connected by Figure 11The wave winding short-span copper bars 211 are connected in the wave winding, and the interval W-phase windings are connected through Figure 11 The wave winding long-span copper bars 212 are connected in the wave winding, and the W-phase phase-out copper bars 213 are directly bent out.

[0095] The stator system of the present application, through the continuous wave winding winding mode, the number of end point welding of the whole stator winding is greatly reduced, each phase winding can be directly wound by continuously bending a single copper wire, without end copper bar welding connection, and the whole stator winding only retains three welding points of the center copper bar to connect the three-phase wave winding.

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

[0097] In an embodiment, the core unit 31 is pressed from soft magnetic composite material.

[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, which has the advantages of magnetic isotropy, high magnetic permeability, low coercivity, high Curie temperature and low loss. The core unit 31 pressed from the soft magnetic composite material, combined with the segmented core group without back yoke, is lighter in weight, less in material, can reduce the occupied volume, and has compact structure.

[0099] In the description of the present application, it should be noted that the positions or position relationships indicated by the terms "upper", "lower" and the like are based on the positions or position relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. Unless otherwise specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integral connection; it can be mechanical connection, or electrical connection; it can be direct connection, or indirect connection through intermediate medium, or internal communication of two elements. For those skilled in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0100] It should be noted that, in the present application, the relational terms such as "first" and "second", and the like, are used solely to distinguish one entity or action from another, without necessarily requiring or implying any actual relationship or order between such entities or actions. Moreover, the terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can also include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by "comprises... a" does not, without more constraints, exclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the element.

[0101] The foregoing is merely illustrative of the principles of the application and various modifications can be made by those skilled in the art without departing from the spirit and scope of the application. The above embodiments are illustrative, and not restrictive, of the scope of the application.

Claims

1. A stator system of an axial flux motor, characterized by, The stator system adopts a three-phase symmetric topology structure, which comprises: a stator winding coil (1) comprising a plurality of axially flat and thin wire coils, each of which is in the shape of an isosceles triangle, both base angles of the isosceles triangle are greater than 60°, and the bending radius of the thin wire coil during the forming process is less than one time the wire width; an end wiring copper bar assembly (2) for wiring connection of the thin wire coils of the stator winding coil (1) according to the three-phase symmetric topology structure, and leading out three-phase soft copper wires (22) connected to the outside; a segmented stator core group (3) without a back yoke, comprising a plurality of core units (31), each of which is independently and separately arranged, and an all-open slot design is adopted between two adjacent core units (31), the thin wire coils of the stator winding coil (1) are nested with the core units (31) of the segmented stator core group (3) to form a winding; the stator system comprises 3(2n+2) windings, which are divided into 3(n+1) positive windings and 3(n+1) negative windings, wherein 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 the windings are symmetrically arranged at the center; the same-phase adjacent windings of the 3(n+1) positive windings or the 3(n+1) negative windings are connected by the short-span copper bars (20); the long-span copper bars (200) connect the spaced same-phase windings; the end wiring copper bar assembly further comprises a center copper bar (21), the short-span copper bars (20) and the long-span copper bars (200) connect the adjacent or spaced same-phase windings; the center copper bar (21) connects three-phase currents after the connection of the short-span copper bars (20) and the long-span copper bars (200); the center copper bar (21), the short-span copper bars (20) and the 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 at the center.

2. A stator system of an axial flux motor as claimed in claim 1, characterized in that: After the thin wire coils of the stator winding coil (1) with the end wiring copper bar assembly (2) are nested in the segmented stator core group (3), a whole impregnation structure is formed by impregnation treatment, and the whole impregnation structure is provided with connection holes for facilitating connection of the three-phase soft copper wires (22).

3. A stator system of an axial flux motor as claimed in claim 2, characterized in that The thin wire coil layers have a set gap, and the set gap is filled with an insulating glue layer during the impregnation treatment.

4. A stator system of an axial flux motor as claimed in claim 1, characterized in that: The radii of the three inner fillets of the thin wire coil are the same, and the radii of the inner fillets are smaller than the wire width of the thin wire coil.

5. A stator system of an axial flux motor as claimed in claim 1, characterized in that: The end wiring copper bar assembly (2) adopts a series copper bar wiring mode or a continuous wave band wiring mode to connect a plurality of windings.

6. A stator system of an axial flux motor as claimed in claim 1, characterized in that: The end wiring copper bar assembly (2) adopts a series copper bar wiring mode or a continuous wave winding wiring mode, in the series copper bar wiring mode, the end wiring copper bar assembly (2) is independent of the stator winding coil (1); in the continuous wave winding wiring mode, the end wiring copper bar assembly (2) and the stator winding coil (1) are integrated.

7. A stator system of an axial flux motor as claimed in claim 1, characterized in that: When n is equal to 2, the winding numbers are 1-12 in anticlockwise order, and the phases and the positive and negative directions of the currents of the windings 1-12 are U+, U-, V-, V+, W+, W-, U-, U+, V+, V-, W- and W+ in turn.

8. A stator system of an axial flux motor as claimed in claim 1, characterized in that: The iron core unit (31) is pressed by using a soft magnetic composite material.

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