Axial magnetic field permanent magnet motor and stator structure and power device thereof

Abstract

The invention discloses an axial magnetic field permanent magnet motor and a stator structure and a power device thereof. The axial magnetic field permanent magnet motor comprises a rotor and a stator structure; the stator structure is clamped between the two rotors in the axial direction; an axial air gap is formed between the rotor and the stator structure; the stator structure comprises a stator casing which comprises an annular casing and a plurality of radiating fins fixed on the inner side of the annular casing; the plurality of stator units are spliced along the circumferential direction to form an annular structure and are accommodated in the annular shell; each stator unit comprises a stator core and an annular winding coil; each radiating fin is inserted between the annular winding coils of two adjacent stator units; the annular winding coil and the cooling fins are of an additive manufacturing forming structure. According to the invention, the stator core, the winding coil and the heat dissipation fins can be tightly attached, the winding slot fullness rate and the heat dissipation effect are improved, the mechanical strength of the stator is enhanced, the coil eddy current loss is inhibited, the higher design freedom degree is realized, and the motor performance is improved.

Description

Technical Field

[0001] This application relates to the field of electrical equipment technology, specifically to an axial magnetic field permanent magnet motor, and more particularly to a stator structure and power device. Background Technology

[0002] Electric drive technology, with its significant advantages in energy conservation, environmental protection, reliability, maintainability, control precision, and response speed, is gradually replacing traditional internal combustion engines, hydraulic and pneumatic drives, and its applications in industrial and civilian fields are becoming increasingly widespread. In particular, high-end applications such as electric vehicle drives, robot servo drives, electric aircraft propulsion, and new energy power generation place extremely stringent requirements on the core performance indicators of motor systems, such as torque density and efficiency. Against this backdrop, permanent magnet synchronous motors, with their comprehensive advantages of high torque density, high efficiency, high design freedom, and low vibration and noise, have become a key focus of current high-performance motor research and development.

[0003] Among the various topologies of permanent magnet synchronous motors (PMSMs), axial magnetic field PMSMs stand out due to their unique magnetic circuit structure, characterized by a large air gap area, compact axial dimensions, and high power / torque density. They are particularly suitable for applications with flat installation spaces, demonstrating significant application potential. To further explore the performance potential of axial magnetic field PMSMs, the industry has developed various structures. Among them, the yokeless single-stator dual-rotor structure is a highly innovative design. This structure cleverly arranges the magnetic poles of the permanent magnets on both sides of the rotor, allowing the main magnetic flux to form a closed loop in the stator. This eliminates the need for the traditional stator core yoke, resulting in high magnetic field strength and a lighter stator weight. Simultaneously, the flat stator windings improve slot fill factor, further enhancing the motor's torque density and efficiency.

[0004] Although yokeless single-stator dual-rotor axial magnetic field permanent magnet motors possess immense potential for high torque density in principle, their actual manufacturing and implementation face severe challenges, particularly in the production of modular stators. The weak structural strength of the stator limits its full performance potential and industrial application. Specifically, existing flat wire winding processing technology, when dealing with modular and irregularly shaped stators, struggles to balance machinability and low losses: either it cannot achieve a tight fit to ensure basic performance, or it cannot employ advanced winding structures to suppress losses due to processing limitations. Furthermore, the spatial magnetic field harmonic content distribution of this type of motor, along with significant eddy current losses in the flat wire windings, sacrifices motor efficiency and further exacerbates stator heating. Summary of the Invention

[0005] In view of this, the purpose of this application is to provide an axial magnetic field permanent magnet motor and its stator structure and power device, which aims to achieve a tight fit between the stator core and the stator winding, improve the mechanical strength of the stator structure, enhance the heat dissipation effect of the stator structure, and reduce the coil eddy current loss.

[0006] To achieve the above objectives, based on one aspect of this application, a stator structure for an axial magnetic field permanent magnet motor is provided, wherein an axial air gap is formed between the stator structure and the rotor, and the stator structure includes:

[0007] A stator housing includes an annular housing and a plurality of heat dissipation fins, each of said heat dissipation fins extending radially along the annular housing and fixed to the inner surface of the annular housing; and,

[0008] Multiple stator units are spliced ​​together circumferentially to form a ring structure and housed within the ring-shaped housing;

[0009] Each of the stator units includes a stator core and an annular winding coil surrounding the stator core;

[0010] Each of the heat dissipation fins is inserted between the annular winding coils of two adjacent stator units;

[0011] Both the annular winding coil and the heat dissipation fins are additively manufactured structures.

[0012] In some embodiments, the heat dissipation fins extend axially at at least one end and cover the corresponding axial end of the annular winding coil.

[0013] In some embodiments, the heat dissipation fins extend at both ends along the axial direction and cover the two axial ends of the annular winding coil, respectively.

[0014] In some embodiments, the heat dissipation fins are connected to the annular winding coil in a concave-convex fit; and / or, the heat dissipation fins are connected to the annular housing in a concave-convex fit.

[0015] In some embodiments, the heat dissipation fins are made of a conductive and non-magnetic metallic material.

[0016] In some embodiments, the annular winding coil is provided with multiple layers of flat wire conductors along the axial direction; and / or, the annular winding coil is provided with multiple layers of flat wire conductors along the tangential direction.

[0017] In some embodiments, axially, the axial thickness of the flat conductors in the multilayer flat conductors near the axial air gap is less than the axial thickness of the flat conductors away from the axial air gap.

[0018] In some embodiments, the stator cores of two adjacent stator units form a parallel slot structure so that the tangential thickness of the annular winding coil is the same at all points along the radial direction; or, the stator cores of two adjacent stator units form a non-parallel slot structure so that the thickness of the annular winding coil gradually increases from the inside to the outside along the radial direction.

[0019] In some embodiments, the toroidal winding coil is made of a flat wire conductor, which may be a hollow or solid structure; when the flat wire conductor is a hollow structure, a cooling medium is introduced into the hollow structure.

[0020] In some embodiments, the annular winding coil and the stator core are connected by a concave-convex fit.

[0021] To achieve the above objectives, based on another aspect of this application, an axial magnetic field permanent magnet motor is also provided, comprising at least two rotors and at least one stator structure as described above; the stator structure is axially sandwiched between the two rotors; an axial air gap is formed between the rotors and the stator structure.

[0022] To achieve the above objectives, based on another aspect of this application, a power device is also provided, including the axial magnetic field permanent magnet motor as described above, the axial magnetic field permanent magnet motor being used to provide power to drive a downstream load.

[0023] The axial magnetic field permanent magnet motor and its stator structure and power unit provided in this application have at least the following beneficial effects:

[0024] On the one hand, additive manufacturing of toroidal winding coils allows for better adaptation to the stator core, overcoming the limitations of traditional processes and enabling the rapid and precise production of toroidal winding coils that meet different size, shape, and positional requirements. This not only ensures a tight fit between the toroidal winding coil and the stator core, eliminating gaps in traditional winding processes and improving winding slot fill factor and heat dissipation, but also strengthens the mechanical strength of the stator structure. Additive manufacturing also allows for flexible arrangement and shape optimization of the toroidal winding coil in the axial and tangential directions, providing greater design freedom to employ advanced winding structures to suppress eddy current losses and improve motor performance.

[0025] On the other hand, each heat sink fin is inserted between two adjacent stator units. This not only provides precise circumferential positioning and robust mechanical fixation for the modular stator units, but also forms an efficient heat conduction path from the annular winding coil to the annular housing, thereby significantly improving the cooling effect of the stator structure and enhancing the motor's continuous operating capability. In terms of manufacturing, the heat sink fins can be integrally formed using additive manufacturing processes. This gives the heat sink fins a high degree of design freedom, allowing for optimization of their shape and contact area with the coil, thus facilitating a synergistic improvement in motor heat dissipation and mechanical performance.

[0026] Further improvements include using conductive and non-magnetic metal materials for the heat dissipation fins, and wrapping the ring-shaped winding coil with the heat dissipation fins circumferentially and axially. This effectively prevents the propagation of spatial harmonic magnetic fields to the ring-shaped winding coil, thereby effectively suppressing the eddy current loss of the coil and reducing the heat generation of the stator. Attached Figure Description

[0027] The accompanying drawings are provided to better understand this application and do not constitute an undue limitation thereof.

[0028] Figure 1 This is a three-dimensional exploded view of the axial magnetic field permanent magnet motor provided in the embodiments of this application;

[0029] Figure 2 A three-dimensional structural schematic diagram of a single stator unit provided in an embodiment of this application;

[0030] Figure 3 This is a schematic cross-sectional view of the parallel slot structure formed by the stator cores of two adjacent stator units provided in an embodiment of this application.

[0031] Figure 4 This is a schematic cross-sectional view of the stator cores of two adjacent stator units forming a non-parallel slot structure, as provided in an embodiment of this application.

[0032] Figure 5 This is a schematic diagram of the axial section of the toroidal winding coil provided in the embodiment of this application, which has several layers of flat wire conductors arranged along the axial direction and a single layer of flat wire conductor arranged along the tangential direction.

[0033] Figure 6 This is a schematic diagram of the axial section of the toroidal winding coil provided in the embodiment of this application, which has several layers of flat wire conductors arranged along the axial direction and two layers of flat wire conductors arranged along the tangential direction.

[0034] Figure 7 A schematic diagram of an axial section showing that when several layers of flat wire conductors are arranged along the axial direction in the toroidal winding coil provided in the embodiment of this application, the axial thickness of the flat wire conductor near the axial air gap is less than the axial thickness of the flat wire conductor far from the axial air gap.

[0035] Figure 8 A schematic diagram of the axial cross-section of the toroidal winding coil using a hollow flat wire conductor, provided in an embodiment of this application;

[0036] Figure 9 This is a schematic diagram of the axial cross-section of the annular winding coil provided in the embodiment of this application, showing the circumferential sides of the coil connected to the heat sink fins in a concave-convex fit.

[0037] Figure 10 This is a schematic cross-sectional view of the annular winding coil provided in the embodiment of this application, in which both sides of the circumference and both ends of the axial direction are covered by heat dissipation fins.

[0038] Explanation of reference numerals in the attached drawings: 1-Stator structure, 10-Stator unit, 11-Stator core, 12-Annular winding coil, 2-First rotor, 3-Second rotor, 21, 31-Rotor core, 22, 32-Rotor permanent magnet, 4-Heat dissipation fins, 5-Cooling medium, 6-Annular shell. Detailed Implementation

[0039] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. This application can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of this application. Therefore, the drawings only show components related to this application and are not drawn according to the actual number, shape, and size of components in the implementation. In actual implementation, the type, quantity, and proportion of each component can be arbitrarily changed, and the component layout may also be more complex.

[0040] Furthermore, while each embodiment described below possesses one or more technical features, this does not imply that users of this application must simultaneously implement all technical features in any embodiment, or can only separately implement some or all technical features in different embodiments. In other words, provided it is feasible, those skilled in the art can selectively implement some or all of the technical features in any embodiment, or selectively implement a combination of some or all of the technical features in multiple embodiments, based on the disclosure of this application and depending on design specifications or actual needs, thereby increasing the flexibility in implementing this application.

[0041] As used herein, the singular forms “a,” “an,” and “the” include plural objects, and the plural form “multiple” includes two or more objects, unless otherwise expressly indicated. As used herein, the term “or” is generally used to include the meaning of “and / or,” unless otherwise expressly indicated, and the terms “installed,” “connected,” and “linked” should be interpreted broadly, for example, as a fixed connection, a detachable connection, or an integral connection. Connections can be mechanical or electrical. Connections can be direct or indirect through an intermediate medium, and can be internal communication between two elements or an interaction between two elements. Relational terms such as “first,” “second,” etc., are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations, nor do they indicate or imply relative importance or implicitly specify the number of indicated technical features. It should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," "radial," and "circumferential," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances. In this document, the term "axial" refers to a direction parallel to or coincident with the axis of rotation of the motor, "radial" refers to a direction perpendicular to the axis of rotation and extending outwards or inwards, and "circumferential" or "tangential" refers to the circumferential direction around the axis of rotation.

[0042] The applicant's research revealed that, in related technologies, to achieve modular design and manufacturing, the stator core of an axial magnetic field permanent magnet synchronous motor is typically designed as a symmetrical trapezoidal structure. The toroidal flat wire winding coil nested within it needs to be precisely fitted to the shape and size of the stator core to achieve a tight fit, thereby achieving high slot fill factor and excellent heat dissipation. However, this stator core geometry presents significant challenges to the winding machining process.

[0043] Specifically, on the one hand, traditional winding forming methods based on flat wire have low processing freedom and make it difficult to accurately form a toroidal coil that can closely fit the outline of the stator core, especially the inner and outer outlines of the non-parallel stator slots formed after circumferential splicing of two adjacent stator cores. This results in an unavoidable gap between the toroidal coil and the stator core.

[0044] On the other hand, while pursuing high torque density, the air gap magnetic field has a relatively high content of spatial harmonics. These harmonics induce significant eddy currents in the flat wire windings, leading to severe winding eddy current losses. This loss not only directly sacrifices the operating efficiency of the motor, but also causes additional local heating in the stator, putting pressure on the system's thermal management.

[0045] In particular, coils manufactured using traditional flat wire winding methods are typically single-turn, oversized conductors with excessively high overall rigidity, making them highly sensitive to high-frequency harmonic magnetic fields and resulting in more severe eddy current losses. Therefore, traditional winding processes struggle to produce windings that fit tightly against the stator core, leading to low slot fill factor, poor heat dissipation, and limited design freedom. Furthermore, in traditional axial magnetic field motors, the stator winding coils face the air gap, where the magnetic field has a high harmonic content, causing significant eddy currents in the winding coils and severe eddy current losses, further exacerbating stator heating.

[0046] In view of this, embodiments of this application provide a stator structure for an axial magnetic field permanent magnet motor. This stator structure can achieve a tight fit between the stator core and the winding coils, improve the mechanical strength of the stator structure, reduce stator heating, and reduce coil eddy current losses. It should be noted that the axial magnetic field permanent magnet motor provided in this application includes, but is not limited to, a single-stator dual-rotor basic configuration. In other cases, it can be extended to a multi-stator configuration, with one rotor arranged on each side of the axial direction of each stator.

[0047] To make the objectives, advantages, and features of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings. It should be noted that the drawings are all in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of this application.

[0048] Figure 1 This is a three-dimensional exploded structural diagram of an axial magnetic field permanent magnet motor provided in an embodiment of this application. Figure 1 As shown, in one aspect, this application provides an axial magnetic field permanent magnet motor and its stator structure 1. As an example, the motor adopts a dual-rotor-single-stator disc structure. Specifically, the axial magnetic field permanent magnet motor includes a stator structure 1, a first rotor 2, and a second rotor 3. The stator structure 1 is axially sandwiched between the first rotor 2 and the second rotor 3, and is parallel to and opposite to them, thereby forming axial air gaps between the stator structure 1 and the first rotor 2 and the second rotor 3 on both axial sides, respectively.

[0049] The first rotor 2 includes a rotor core 21 and a plurality of rotor permanent magnets 22 mounted on the rotor core 21; the rotor permanent magnets 22 are mounted on the side of the rotor core 21 near the stator structure 1. The second rotor 3 includes a rotor core 31 and a plurality of rotor permanent magnets 32 mounted on the rotor core 31; the rotor permanent magnets 32 are mounted on the side of the rotor core 31 near the stator structure 1. Therefore, both rotors have rotor permanent magnets located near the axial air gap side and rotor cores located away from the axial air gap side.

[0050] The rotor permanent magnet 21 of the first rotor 2 and the rotor permanent magnet 31 of the second rotor 3 can have the same shape and size, or different shapes and sizes. Furthermore, the number of magnetic poles of the rotor permanent magnets on each rotor is even, and the magnetic pole polarities of any two adjacent rotor permanent magnets are opposite.

[0051] The rotor permanent magnets are all made of high-conductivity materials, which can provide good conduction paths for the axial and circumferential magnetic fields of the motor. The processing method of the rotor core is not limited, for example, multi-layer electrical steel / amorphous alloy winding and machining, multi-layer electrical steel / amorphous alloy radial stacking, powdered soft magnetic composite (SMC) die casting, etc.

[0052] This application does not limit the magnetization direction of the rotor permanent magnets. For example, it can use different magnetization directions such as parallel magnetization perpendicular to the air gap plane or composite Halbach magnetization. In a specific example, the magnetic pole directions of the rotor permanent magnet 21 of the first rotor 2 and the rotor permanent magnet 31 of the second rotor 3 are both along the axial direction, and the number of pole pairs of the rotor permanent magnets 21 and 31 on the two rotors are equal. They are axially aligned one-to-one, but the magnetic pole directions of the two corresponding rotor permanent magnets that are axially aligned are opposite. For example, the magnetic pole of the axially aligned rotor permanent magnet 21 is the N pole, and the magnetic pole of the corresponding rotor permanent magnet 31 is the S pole.

[0053] This application does not impose any particular limitation on the matching method of the number of phases and the number of stator and rotor pole slots of the axial magnetic field permanent magnet motor. That is, the axial magnetic field permanent magnet motor of this application is applicable to different numbers of phases and different stator and rotor pole slot combinations. In a specific example, the axial magnetic field permanent magnet motor described in this application has a three-phase stator with 18 slots and a rotor with 20 poles, that is, an 18-slot 20-pole combination, which belongs to fractional slot winding.

[0054] Continue to refer to Figure 1 The stator structure 1 is a complete ring structure, and is generally a perfect circle structure, and adopts a modular design. In the modular design of the stator, each stator core 11 adopts a yokeless design, which facilitates the nesting of the ring winding coil 12, and the ring winding coil 12 is a concentrated winding, so that each modular stator unit 10 can be manufactured and designed independently.

[0055] Figure 2 This is a three-dimensional structural schematic diagram of a single stator unit 10 provided in an embodiment of this application. Figure 1 and Figure 2 As shown, the stator structure 1 includes multiple stator units 10, which are spliced ​​together circumferentially to form a ring structure. Each stator unit 10 has the same structure and is independent of the others. It should be noted that this application does not limit the slot shape of the stator structure 1; it can adopt a straight slot structure without circumferential twist or an inclined slot structure.

[0056] Each stator unit 10 includes a stator core 11 and an annular winding coil 12. The annular winding coil 12 is a single integral component, sleeved around the outside of the stator core 11. Each annular winding coil 12 is typically made of flat wire conductors (e.g., rectangular), which reduces the circular gaps that cannot be utilized between conventional round wires, thus improving the motor winding slot fill factor. Furthermore, preferably, each stator core 11 has a symmetrical trapezoidal structure, and the stator cores 12 of adjacent stator units 10 can be configured with parallel slot structures or non-parallel slot structures, such as... Figure 3 and Figure 4 As shown.

[0057] Stator structure 1 also includes a stator housing. Please refer to [reference needed]. Figure 3 The stator housing includes an annular shell 6 and multiple heat dissipation fins 4, which together serve as the support and heat dissipation base for the modular stator unit 10. Specifically, each heat dissipation fin 4 extends radially along the annular shell 6 and is fixed to the inner surface of the annular shell 6. This fixed connection needs to have sufficient mechanical strength to bind the multiple stator units 10 together as a whole, ensuring the strength of the overall stator structure.

[0058] Continue to refer to Figure 3 Each heat dissipation fin 4 is inserted between the annular winding coils 12 of two adjacent stator units 10, and is sandwiched between the two adjacent stator units 10 in the circumferential direction. It can be understood that each heat dissipation fin 4 is tightly fitted with the annular winding coil 12 in the circumferential position, so that the two adjacent stator units 10 are connected through the heat dissipation fin 4. That is, both sides of the annular winding coil 12 of each stator unit 10 are connected to the annular winding coil 12 of the adjacent stator unit 10 through the heat dissipation fin 4.

[0059] Specifically, the number of heat dissipation fins 4 is the same as the number of stator units 10. In this configuration, each heat dissipation fin 4 can be precisely inserted between two adjacent stator units 10 (as shown in the figure), thereby simultaneously achieving precise circumferential positioning of the stator unit 10 and establishing an efficient heat conduction path between adjacent annular winding coils 12.

[0060] Thus, the annular structure formed by multiple stator units 10 spliced ​​circumferentially is coaxially assembled and housed within the annular housing 6. Furthermore, the radially outer surface of the stator unit 10 maintains close physical contact with the inner surface of the annular housing 6, thereby establishing an efficient heat conduction path from the inside out between the two.

[0061] Equally important, the annular housing 6 can tightly constrain and fix multiple originally independent stator units 10 in the circumferential and radial directions, integrating them into a whole with high structural integrity. This design improves the mechanical strength and rigidity of the stator structure 1.

[0062] The axial magnetic field permanent magnet motor described in this application follows the general principle of permanent magnet synchronous motors: during operation, a multi-phase symmetrical sinusoidal current is passed into multiple annular winding coils 12 of the stator structure 1, thereby generating a spatially rotating magnetic field around the stator core 11.

[0063] The unique feature of this application lies in the use of modular stator units 10. Each stator unit 10's annular winding coil 12 establishes an efficient thermally conductive connection with the annular housing 6 via heat dissipation fins 4 on both circumferential sides. Therefore, the circumferentially assembled structure of multiple stator units 10, together with the rotors on both sides, forms a highly symmetrical axial magnetic field path with a uniform air gap. This rotating magnetic field interacts with the permanent magnet magnetic fields on the rotors on both sides, generating a smooth and continuous axial electromagnetic torque that drives the motor to rotate.

[0064] The heat generated by the winding copper loss and core iron loss during the above-mentioned operation can be efficiently dissipated through the integrated heat dissipation path formed by the heat dissipation fins 4 and the annular shell 6. This structure ensures that the annular winding coil 12 can maintain a suitable operating temperature even when operating at a high current density, thereby allowing the motor to operate stably under continuous high torque output or overload conditions, achieving synergistic optimization of electromagnetic performance and heat dissipation capacity.

[0065] On the other hand, both the toroidal winding coil 12 and the heat dissipation fins 4 are integrally formed using additive manufacturing (3D printing), meaning that both the toroidal winding coil 12 and the heat dissipation fins 4 are additively manufactured structures. It is understandable that the toroidal winding coil 12 and the heat dissipation fins 4 can be manufactured independently and then assembled.

[0066] In this way, by employing additive manufacturing, a gapless fit can be achieved between the stator core 11, the annular winding coil 12, and the heat dissipation fins 4. This not only improves the winding slot fill factor but, more importantly, creates a near-ideal heat conduction interface, maximizing heat dissipation. Simultaneously, the tight fit and optimized shape help suppress coil eddy current losses, improving motor performance. Moreover, the gapless tight fit imparts high rigidity and integrity to the stator units 10, thereby enhancing the mechanical strength of the stator structure 1. This process breaks through the constraints of traditional manufacturing methods, allowing for optimization of the electromagnetic topology, heat dissipation path, and mechanical structure of the stator structure 1, facilitating the adoption of advanced structures to improve motor performance.

[0067] Furthermore, through additive manufacturing, each toroidal winding coil 12 can be precisely fitted to the modular stator core 11. This breaks through the limitations of traditional processes, enabling the rapid and precise manufacture of winding coils that meet the requirements of different sizes, shapes, and positions. In particular, it can accommodate stator cores 11 with non-parallel slot designs. Thus, the shape and size of the toroidal winding coil 12 can be freely adjusted to precisely match the stator core 11. This not only demonstrates excellent processing flexibility but also aims to maximize space utilization and heat dissipation performance.

[0068] To achieve the best balance between material cost, processing reliability and final electromagnetic performance, the toroidal winding coil 12 can be made of materials with high conductivity and high processability, such as copper, aluminum or their corresponding powder alloys.

[0069] In addition, the heat dissipation fins 4 are made of metal materials with good strength, good thermal conductivity, good electrical conductivity and no magnetic properties, such as aluminum alloy and stainless steel, so as to improve the heat dissipation effect while suppressing coil eddy current losses.

[0070] refer to Figure 3 As shown, the heat dissipation fins 4 are tightly fitted (including adhered) to the annular winding coil 12 on at least two circumferential sides.

[0071] Preferably, based on this close fit, the heat dissipation fins 4 and the annular winding coil 12 can be mechanically connected by filling with thermally conductive potting compound or by using a concave-convex fit, thereby increasing the contact area and enhancing the connection strength between the interfaces.

[0072] Preferably, the heat dissipation fins 4 and the annular winding coil 12 form a multi-dimensional cooperation.

[0073] In some embodiments, the heat dissipation fins 4 may extend radially inward toward the annular winding coil 12, so that the radially inward side of the annular winding coil 12 also maintains a close fit with the heat dissipation fins 4, thereby increasing the contact area between the two and optimizing radial heat conduction.

[0074] In some embodiments, the heat dissipation fins 4 are axially engaged with the annular winding coil 12 in such a way that they wrap around it. Specifically, at least one axial end of the heat dissipation fins 4 extends and covers and abuts the corresponding axial end of the annular winding coil 12.

[0075] Figure 10 This is a schematic cross-sectional view of the annular winding coil 12 provided in this embodiment, where both circumferential sides and axial ends are wrapped by heat dissipation fins 4. Figure 10 As shown, as a more preferred embodiment, the heat dissipation fins 4 extend at both ends along the axial direction and cover the two axial ends of the annular winding coil 12, thereby enclosing the annular winding coil 12.

[0076] Specifically, the toroidal winding coil 12 is wrapped with conductive, non-magnetic heat dissipation fins 4 on both its circumferential and axial outer sides. These heat dissipation fins 4 are irregularly shaped and can be integrally formed using additive manufacturing processes. In this structure, the toroidal winding coil 12 is fully wrapped by the heat dissipation fins 4, which protects the coil, reduces eddy current losses, and lowers the heat generation of the motor stator winding. In other words, this axially wrapped structure prevents the conductor of the toroidal winding coil 12 from being directly exposed to the axial air gap, effectively suppressing eddy current losses caused by the coil's ends being close to the axial air gap, thereby reducing stator heat generation.

[0077] For each stator unit 10, the inner surface of its annular winding coil 12 (i.e. the surface surrounding the stator core 11) and the outer surface of the stator core 11 maintain a tight fit as a whole.

[0078] Preferably, the inner surface of the toroidal winding coil 12 and the outer surface of the stator core 11 can be mechanically connected by filling with thermally conductive potting compound or by designing complementary concave-convex fits. This not only increases the effective contact area but also strengthens the connection between the stator units 10, thereby increasing the overall structural stability of the stator.

[0079] The outer radial surface of the annular winding coil 12 and the inner surface of the annular housing 6 also maintain a tight fit. Preferably, the inner surface of the annular housing 6 and the outer radial surface of the annular winding coil 12 can be mechanically connected by filling with thermally conductive potting compound or by using a tongue-and-groove joint. In addition, the annular housing 6 and the heat dissipation fins 4 can be mechanically connected by a tongue-and-groove joint (such as a tenon or mortise structure or a serrated structure), bolts, or other means.

[0080] Figure 9 This is a schematic cross-sectional view of the circumferential sides of the annular winding coil 12 provided in this embodiment of the application, showing the concave-convex connection between the coil and the heat sink fins 4. Figure 9As shown, as a preferred embodiment, the contact surface between the heat dissipation fins 4 and the annular winding coil 12 is configured with a sawtooth structure, thereby increasing the contact area between the two and improving the fit and heat dissipation effect.

[0081] Similarly, the contact surfaces between the stator core 11 and the annular winding coil 12, as well as the contact surfaces between the annular winding coil 12 and the annular housing 6, can all be configured as serrated structures.

[0082] Furthermore, the high degree of design freedom of the toroidal winding coil 12 allows for optimization of the shape of the stator core 11, thereby improving motor performance.

[0083] Figure 3 This is a cross-sectional schematic diagram showing the parallel slot structure formed by the stator cores 11 of two adjacent stator units 10 provided in an embodiment of this application. Figure 3 As shown, in some embodiments, the stator cores 11 of two adjacent stator units 10 are arranged parallel to each other along their circumferentially distributed sides, forming a parallel slot structure. This makes the thickness t1 of the annular winding coil 12 the same at all radial locations when it is distributed around the stator core 12. Thus, the annular winding coil 12 has the same cross-sectional shape and size at different radial positions and fits tightly with the stator core 12, adapting to the conventional parallel slot design.

[0084] In addition, Figure 3 As can be seen, both sides of the annular winding coil 12 are in close contact with the heat dissipation fins 4, and the outer radial side of the annular winding coil 12 is in close contact with the inner surface of the annular shell 6, forming an integral structure, which improves the mechanical structure strength and heat dissipation effect of the stator.

[0085] Figure 4 This is a schematic cross-sectional view of the stator cores 11 of two adjacent stator units 10 forming a non-parallel slot structure, as provided in an embodiment of this application. Figure 4 As shown, in some embodiments, the stator cores 11 of two adjacent stator units 10 are arranged at an angle along their circumferentially distributed sides, with no limitation on the angle, forming a non-parallel slot structure. In this case, when the annular winding coil 12 is distributed around the stator core 11, its thickness t2 gradually increases radially from the inside out, resulting in the annular winding coil 12 having different dimensions at different radial positions. This non-parallel slot design overcomes the technological limitation that traditional flat wire windings must use a parallel slot design.

[0086] More importantly, through additive manufacturing, the toroidal winding coil 12 can be precisely shaped into a three-dimensional structure that fits tightly against the non-parallel slot stator core 11. This eliminates the unavoidable gap between the conductor and the core in traditional winding processes, achieving maximum utilization of stator slot space and significantly improving the winding slot fill factor. Simultaneously, the precise arrangement of the conductors optimizes the magnetic field distribution, helping to reduce leakage flux, improve the sinusoidal nature of the air gap magnetic flux density, and thus improve the motor's torque performance and suppress torque ripple.

[0087] On the other hand, thanks to additive manufacturing, the shape and size of the toroidal winding coil 12 in the axial and circumferential directions can be optimized, thereby suppressing eddy current losses in the motor winding and reducing DC copper losses in the winding.

[0088] Specifically, the toroidal winding coil 12 may be provided with one or more layers of flat wire conductors along the axial direction, and the cross-sectional shape and size of the flat wire conductors at different axial positions in the multiple layers of flat wire conductors may be the same or different.

[0089] Figure 7 This is a schematic cross-sectional view showing that, when the toroidal winding coil 12 provided in this embodiment of the application has several layers of flat wire conductors arranged axially, the axial thickness of the flat wire conductors near the axial air gap is smaller than the axial thickness of the flat wire conductors far from the axial air gap. (See attached image.) Figure 7 As shown, in a preferred embodiment, the axial thickness of the flat wire conductors near the axial air gap in the multilayer flat wire conductors is smaller than the axial thickness of the flat wire conductors farther from the axial air gap. This configuration reduces winding eddy current losses when the axial thickness of the flat wire conductors near the axial air gap is smaller, and reduces winding DC copper losses when the axial thickness of the flat wire conductors farther from the axial air gap is larger.

[0090] In addition, one or more layers of flat wire conductors can be provided along the tangential direction of the toroidal winding coil 12, and the cross-sectional shape and size of the flat wire conductors at different circumferential positions can be the same or different.

[0091] Figure 5 This is a schematic cross-sectional view of the toroidal winding coil 12 provided in this embodiment, showing several layers of flat wire conductors arranged axially and a single layer of flat wire conductor arranged tangentially. Figure 5 As shown, in some embodiments, when the annular winding coil 12 is provided with multiple layers of flat wire conductors along the axial direction, the cross-sectional shape and size of the flat wire conductors at different axial positions are the same.

[0092] Figure 6 This is a schematic axial cross-sectional view of the toroidal winding coil 12 provided in this embodiment, showing several layers of flat wire conductors arranged axially and two layers of flat wire conductors arranged tangentially. Figure 6As shown, in some embodiments, when the annular winding coil 12 is provided with multiple layers of flat wire conductors in both the axial and circumferential directions, the cross-sectional shape and size of the flat wire conductors at different axial and circumferential positions are the same.

[0093] It should be understood that, compared to Figure 5 , Figure 6 The illustrated circumferential multilayer conductor scheme is advantageous in reducing the cross-sectional area of ​​a single-turn flat conductor, thereby helping to suppress eddy currents in the coil. In particular, additive manufacturing significantly reduces the processing difficulty of the circumferential multilayer conductor. Furthermore, compared to… Figure 5 , Figure 7 The non-uniform axial dimension design shown is beneficial for balancing the suppression of eddy current losses in the coil with the reduction of DC copper losses.

[0094] Therefore, additive manufacturing allows for a high degree of design freedom in the toroidal winding coil 12. Its number of turns and conductor layers can be flexibly and independently optimized according to electromagnetic and heat dissipation requirements, without being limited by traditional winding processes. However, please note that the scope of protection of this application is not limited to any specific number of turns or layers. All toroidal winding coils 12 implemented using the additive manufacturing concept described in this application fall within the scope of protection of this application.

[0095] Furthermore, thanks to the flexibility of additive manufacturing processes, the internal structure of the flat wire conductor can be customized to meet performance requirements. It can be manufactured as a solid structure or designed as a hollow structure.

[0096] Figure 8 This is a schematic cross-sectional view of the toroidal winding coil 12 provided in this embodiment of the application, which uses a hollow flat wire conductor. Figure 8 As shown, in some embodiments, the toroidal winding coil 12 uses a hollow flat wire conductor, the interior of which is hollow. This configuration helps to reduce winding weight, enhance winding heat dissipation, and suppress the skin effect of the winding.

[0097] Preferably, the hollow structure of the flat conductor is configured as a cooling channel, through which a cooling medium 5 with high thermal conductivity is introduced to further enhance winding cooling. The cooling medium 5 can be air, water, oil, a special coolant, etc., to further improve winding heat dissipation.

[0098] To ensure reliable motor operation, each toroidal winding coil 12 requires insulation treatment to achieve inter-turn insulation, phase-to-phase insulation, and insulation to ground. This application provides several alternative insulation implementation schemes, as follows:

[0099] In some embodiments, a post-processing insulation process is employed. Specifically, after the toroidal winding coil 12 is integrally formed using an additive manufacturing process, it is immersed entirely in insulating varnish and subsequently cured to form a dense insulating film on its surface and in its internal gaps. This method is a mature technology with good coverage.

[0100] In other embodiments, an integrated additive manufacturing insulation process is employed. This process completes insulation simultaneously during the printing process. Specifically, after each conductor layer is printed, a high-performance insulating material (such as polyamide, ceramic paste, etc.) is used to precisely print an insulating layer on the surface of the formed conductor by switching the printing material, and then the next conductor layer is printed. This process is repeated until a toroidal winding coil 12, in which the conductor and insulator are integrally formed in three-dimensional space, is finally manufactured. This method enables optimal control of insulation layer thickness and spatial distribution, and further simplifies the production process.

[0101] It is worth noting that in some embodiments, the stator core 11 can also be additively manufactured and formed, and it can be integrally formed with the toroidal winding coil 12 or formed independently and then assembled.

[0102] Furthermore, this application embodiment also provides a power device, including the axial magnetic field permanent magnet motor described in this application embodiment, which is used to provide power to drive a downstream load.

[0103] In summary, the axial magnetic field permanent magnet motor and its stator structure and power device provided according to the embodiments of this application have at least the following beneficial effects:

[0104] First, the motor stator adopts a fully modular design, and its windings and core can be processed independently. The flexible structure greatly shortens the processing cycle of individual components, reduces the dependence on large-scale, specialized processing equipment, and simplifies the production process.

[0105] Secondly, the heat dissipation fins are inserted between two adjacent stator units, providing precise circumferential positioning and a firm mechanical fixation for the modular stator units. They also form an efficient heat conduction path from the annular winding coil to the annular shell, significantly improving the heat dissipation effect of the stator.

[0106] Third, the heat dissipation fins are made of conductive and non-magnetic metal materials, and the heat dissipation fins are wrapped around the annular winding coil in the circumferential and axial directions. This can protect the coil from the influence of spatial magnetic field harmonics, reduce coil eddy current losses, and reduce stator heating.

[0107] Fourth, combined additive manufacturing enables: precise layering and arrangement of stator windings in the axial and circumferential directions, breaking through the constraints of traditional flat wire winding processes; flexible control of the cross-sectional dimensions of each turn or layer of conductor, effectively suppressing eddy current losses in the windings by optimizing current density distribution; and, in particular, enabling variable cross-section conductor designs: for example, making the axial thickness of conductors near the air gap thinner to reduce eddy current losses caused by alternating magnetic fields; while simultaneously making the axial thickness of conductors farther from the air gap greater to provide a larger conductive cross-sectional area and reduce DC copper losses; and allowing conductors to be directly manufactured into hollow structures, providing a more efficient and efficient manufacturing process. Creating cooling channels creates space; specifically, cooling media can be introduced into the hollow structure of the flat conductor to achieve direct internal cooling of the winding, resulting in heat dissipation efficiency that traditional solid windings cannot achieve. It also allows for flexible design of the flat conductor's surface shape (such as irregular, non-planar, or micro-convex / concave structures), significantly increasing the contact area with the iron core, annular shell, or heat sink fins, creating an efficient heat conduction path. Furthermore, it provides ample space for selecting winding materials, facilitating a comprehensive balance between material conductivity, printability, mechanical strength, and cost, achieving the optimal balance between overall motor performance and manufacturing cost.

[0108] Finally, it should be noted that although this application discloses the above information, it is not limited thereto. Those skilled in the art can make various modifications and variations to this application without departing from its spirit and scope. Therefore, if such modifications and variations fall within the scope of this application's specification and its equivalents, this application also intends to include such modifications and variations.

Claims

1. A stator structure for an axial magnetic field permanent magnet motor, wherein an axial air gap is formed between the stator structure and the rotor, characterized in that, The stator structure includes: A stator housing includes an annular housing and a plurality of heat dissipation fins, each of said heat dissipation fins extending radially along the annular housing and fixed to the inner surface of the annular housing; and, Multiple stator units are spliced ​​together circumferentially to form a ring structure and housed within the ring-shaped housing; Each of the stator units includes a stator core and an annular winding coil surrounding the stator core; Each of the heat dissipation fins is inserted between the annular winding coils of two adjacent stator units; Both the annular winding coil and the heat dissipation fins are additively manufactured structures.

2. The stator structure of the axial magnetic field permanent magnet motor according to claim 1, characterized in that, The heat dissipation fins extend axially at at least one end and cover the corresponding axial end of the annular winding coil.

3. The stator structure of the axial magnetic field permanent magnet motor according to claim 2, characterized in that, The heat dissipation fins extend at both ends along the axial direction and cover the two axial ends of the annular winding coil.

4. The stator structure of the axial magnetic field permanent magnet motor according to claim 1, characterized in that, The heat dissipation fins are connected to the annular winding coil through a concave-convex fit; and / or, the heat dissipation fins are connected to the annular shell through a concave-convex fit.

5. The stator structure of the axial magnetic field permanent magnet motor according to claim 1, characterized in that, The heat dissipation fins are made of a conductive and non-magnetic metal material.

6. The stator structure of the axial magnetic field permanent magnet motor according to claim 1, characterized in that, The annular winding coil is provided with multiple layers of flat wire conductors along the axial direction; and / or, the annular winding coil is provided with multiple layers of flat wire conductors along the tangential direction.

7. The stator structure of the axial magnetic field permanent magnet motor according to claim 6, characterized in that, In the axial direction, the axial thickness of the flat wire conductors in the multilayer flat wire conductors that are closer to the axial air gap is less than the axial thickness of the flat wire conductors that are farther away from the axial air gap.

8. The stator structure of the axial magnetic field permanent magnet motor according to claim 1, characterized in that, The stator cores of two adjacent stator units form a parallel slot structure so that the tangential thickness of the annular winding coil is the same at all points along the radial direction; or, the stator cores of two adjacent stator units form a non-parallel slot structure so that the thickness of the annular winding coil gradually increases from the inside to the outside along the radial direction.

9. The stator structure of the axial magnetic field permanent magnet motor according to claim 1, characterized in that, The toroidal winding coil is made of flat wire conductors, which can be hollow or solid; when the flat wire conductor is hollow, a cooling medium is introduced into the hollow structure.

10. The stator structure of the axial magnetic field permanent magnet motor according to claim 1, characterized in that, The annular winding coil and the stator core are connected by a concave-convex fit.

11. An axial magnetic field permanent magnet motor, characterized in that, The stator structure comprises at least two rotors and at least one stator structure of an axial magnetic field permanent magnet motor as described in any one of claims 1-10; the stator structure is axially sandwiched between the two rotors; an axial air gap is formed between the rotors and the stator structure.

12. A power unit, characterized in that, Includes the axial magnetic field permanent magnet motor as described in claim 11, the axial magnetic field permanent magnet motor being used to provide power to drive a downstream load.

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