A coreless stator and axial flux motor with high magnetic density and thin working area

Abstract

This invention provides a coreless stator with a high magnetic flux density and a thin working area, and an axial flux motor. The coreless stator includes a first winding unit and a second winding unit stacked axially. Several winding coils of the first and second winding units are fabricated on a conductive substrate using a subtractive process. Each winding coil includes a working area, a hollow slot, and bent outer and inner coil bridging areas. The first and second winding units are circumferentially misaligned during axial stacking, so that the working areas of the first and second winding units are circumferentially spaced and distributed in the same radial plane, forming the stator working section. The thickness of the stator working section does not exceed half the total thickness of the coreless stator. This application further thins the stator working section of the coreless stator, significantly reducing the effective working air gap length of the axial flux motor, significantly enhancing the air gap magnetic flux density, improving the motor's torque density and power density, and achieving synergistic optimization of performance and reliability.

Description

Technical Field

[0001] This invention relates to the field of motor technology, and in particular to a coreless stator and axial flux motor with a high magnetic flux density and thin working area. Background Technology

[0002] Currently, coreless stator axial flux motors have attracted widespread attention in space- and weight-sensitive fields such as electric transportation, industrial drives, and aerospace, thanks to their advantages including disc structure, short axial dimensions, and high power / torque density. Among them, axial flux motors with a single stator and dual rotor configuration have advantages such as symmetrical magnetic circuit, high torque density, and potential for zero stator iron loss, making them an ideal choice for achieving ultra-high power density.

[0003] As is well known, the air gap length of a motor is one of the core parameters affecting its performance. The air gap magnetic flux density is approximately inversely proportional to the air gap length; the smaller the air gap length, the greater the magnetic flux density. Theoretically, to obtain a stronger air gap magnetic field and higher electromagnetic force, the air gap length should be minimized as much as possible. However, in an axial flux motor with a single stator and dual rotor configuration, the physical air gap is determined by the axial distance between the permanent magnet surface of the rotor section and the stator working surface. However, the coreless stator itself needs sufficient structural thickness (including windings, insulation, and encapsulation materials) to maintain its mechanical integrity and heat dissipation capacity. Therefore, the minimum physical thickness of the coreless stator directly determines the lower limit of the minimum achievable air gap for the axial flux motor.

[0004] In existing coreless stator manufacturing processes, single-layer windings are first laser-engraved from copper plates. Multiple single-layer windings are then axially stacked and encapsulated into a composite material plate of uniform thickness. The final thickness depends on the number of layers and the sum of the thicknesses of the interlayer insulation materials. Clearly, the existing manufacturing process is simple and structurally robust, but it does not differentiate the stator's functional areas. This results in the working and non-working areas (referring to the inner and outer ring bridging areas) using the same thickness and material standards, which is not structurally optimal. The overall thickness maintained by existing coreless stators to ensure the strength of the non-working area ultimately becomes a constraint on improving the performance of the working area. This leads to a relatively thick overall thickness in the working area, making further thinning difficult, thus limiting the reduction of the air gap in axial flux motors. Consequently, the magnetic flux density of axial flux motors decreases due to the limited air gap length. Summary of the Invention

[0005] In view of the shortcomings of the prior art described above, the purpose of the present invention is to provide a coreless stator with a high magnetic flux density and a thin working area, further reducing the working area of ​​the coreless stator and enhancing the magnetic flux density.

[0006] To achieve the above objectives, the present invention provides a coreless stator with a high magnetic flux density and thin working area, comprising an axially stacked first winding unit and a second winding unit, wherein each of the first winding unit and the second winding unit comprises at least one single-layer winding, and each single-layer winding comprises several circumferentially spaced and mutually independent winding coils.

[0007] Each single-layer winding has several winding coils that are fabricated on a conductive substrate using a subtractive process. Each winding coil includes a working area distributed in a radial plane, an outer ring bridging area connected to the outer ring of the working area, an inner ring bridging area connected to the inner ring of the working area, and a hollow slot formed by the working area, the outer ring bridging area, and the inner ring bridging area. The conductor ends of each winding coil are an outer solder pad and an inner solder pad, respectively. The working area is used to face the permanent magnet of the rotor in the axial flux motor. The outer ring bridging area and the inner ring bridging area are both bent in the same direction relative to the working area. The central angle occupied by the adjacent working areas of two adjacent winding coils is smaller than the central angle occupied by the hollow slot of a single winding coil.

[0008] When the first winding unit and the second winding unit are axially stacked, they are circumferentially misaligned. The working area of ​​the winding coil in the first winding unit is embedded in the hollow slot of the winding coil in the second winding unit, and the working area of ​​the winding coil in the second winding unit is embedded in the hollow slot of the winding coil in the first winding unit. This allows the working areas of several winding coils in the first winding unit and several winding coils in the second winding unit to be circumferentially spaced and distributed in the same radial plane, forming the stator working section. The thickness does not exceed 1 / 2 of the total thickness of the coreless stator. The outer ring bridging areas of several winding coils of the first winding unit and the outer ring bridging areas of several winding coils of the second winding unit are axially stacked to form the outer bridging end. The inner ring bridging areas of several winding coils of the first winding unit and the inner ring bridging areas of several winding coils of the second winding unit are axially stacked to form the inner bridging end. The outer end side of the stator working part, the inner peripheral side of the outer bridging end, and the outer peripheral side of the inner bridging end are formed with magnet mounting areas for accommodating permanent magnets of the rotor.

[0009] Furthermore, both the first winding unit and the second winding unit include several layers of single-layer windings;

[0010] In the first winding unit, the bending directions of the outer and inner bridging areas of the several single-layer windings are the same;

[0011] In the second winding unit, the bending directions of the outer and inner bridging areas of the several single-layer windings are the same;

[0012] The bending directions of the outer and inner bridging areas of the first winding unit are opposite to those of the outer and inner bridging areas of the second winding unit, so that the stator working part has magnet mounting areas on both ends in its thickness direction.

[0013] Furthermore, both the first winding unit and the second winding unit include several layers of single-layer windings;

[0014] In the first winding unit, several winding coils of several single-layer windings are aligned one by one. The inner solder pads of the several aligned winding coils in the several single-layer windings are electrically connected, so that the several aligned winding coils are continuously wound and form a circuit.

[0015] In the second winding unit, several winding coils of several single-layer windings are aligned one by one. The inner solder pads of the aligned winding coils in the several single-layer windings are electrically connected, so that the aligned winding coils are continuously wound and form a circuit.

[0016] Furthermore, the inner pads of several aligned winding coils are aligned and fixed by laser welding or soldering.

[0017] Furthermore, both the first winding unit and the second winding unit include several layers of single-layer windings;

[0018] There is an insulating gap between two adjacent single-layer windings of the first winding unit and between two adjacent single-layer windings of the second winding unit, and they are fixed by insulating glue filled in the insulating gap.

[0019] Furthermore, the working area includes several circumferentially arranged radially straight conductor segments that all extend radially, with a gap formed by a subtractive material process between two circumferentially adjacent radially straight conductor segments.

[0020] Furthermore, the winding profile of the winding coil is a hollow concentric profile, including a multi-turn concentric coiled conductor ring formed after a material reduction process;

[0021] The adjacent inner and outer rings of the multi-turn concentric coiled conductor ring have gaps formed by a material reduction process. The outer ring bridging area includes several radially parallel outer transition connection sections that all extend circumferentially. The inner ring bridging area includes several radially parallel inner transition connection sections that all extend circumferentially. The radial straight conductor section is connected to the outer transition connection section, and the radial straight conductor section is connected to the inner transition connection section by arc segments.

[0022] Furthermore, the winding profile of the winding coil is a single-unit distributed profile, comprising multiple concentric conductor rings formed by a subtractive process, with the multiple concentric conductor rings arranged inside and outside each other, and a gap formed by the subtractive process between adjacent inner and outer concentric conductor rings.

[0023] Furthermore, the conductive substrate is a copper plate, an aluminum plate, or a silicon steel plate, and the subtractive material process is laser etching.

[0024] The present invention also provides an axial flux motor, comprising a motor housing, a motor shaft rotatably mounted in the motor housing, a first rotor disk and a second rotor disk rotatably mounted in the motor housing and fixed to the outer periphery of the motor shaft, and a coreless stator with a high magnetic flux density thin working area as described above. The first rotor disk and the second rotor disk each include a plurality of circumferentially spaced permanent magnets, and the polarities of two circumferentially adjacent permanent magnets and two axially facing permanent magnets are opposite. The coreless stator with the high magnetic flux density thin working area is assembled between the first rotor disk and the second rotor disk. The permanent magnets of the first rotor disk and the second rotor disk are rotatably assembled in the magnet mounting area of ​​the coreless stator and are axially facing the stator working part of the coreless stator.

[0025] As described above, the coreless stator and axial flux motor with high magnetic flux density and thin working area of ​​the present invention have the following beneficial effects:

[0026] 1. Enhanced air gap magnetic flux density, improving motor torque and power density: By setting the outer and inner bridging regions of several winding coils in a single-layer winding to be bent in the same direction relative to the working area, and by setting hollow slots in each winding coil, when the first and second winding units are axially stacked in a circumferentially staggered manner, the working areas of the first and second winding units can be distributed in the same radial plane. This further reduces the thickness of the stator working section of the coreless stator, and allows the coreless stator to form a magnet mounting area for accommodating permanent magnets on the outside of the stator working section, thereby significantly reducing the effective working air gap length of the axial flux motor. The reduction in the effective working air gap length directly leads to a significant enhancement of the air gap magnetic flux density. In the electromagnetic design of the axial flux motor, the output torque is proportional to the square of the air gap magnetic flux density. Thus, with the same volume and amount of permanent magnets in the axial flux motor, this application enables the axial flux motor to output higher torque and power, significantly improving the torque density and power density of the motor, and solving the core bottleneck of the prior art, which is that the stator working area is too thick, resulting in excessive air gap and insufficient magnetic density.

[0027] 2. Achieving Synergistic Optimization of Performance and Reliability: This application does not simply reduce the overall thickness of the coreless stator, but rather adopts a "zonal design, function-oriented" approach to achieve extreme thinning in the working area of ​​the coreless stator to optimize electromagnetic performance. At the outer and inner bridging ends of the coreless stator, axial stacking of multi-layered bending structures is used to strengthen the structure, ensuring the overall mechanical strength, rigidity, and heat dissipation capacity of the coreless stator. This application's coreless stator overcomes the limitations of traditional "uniform thickness" packaging schemes. While pursuing ultimate electromagnetic performance, it fundamentally ensures the long-term reliability of the coreless stator under high-speed rotation, electromagnetic impact, and thermal cycling, resolving the inherent contradiction between thinning and strength.

[0028] 3. Expanded application prospects of axial flux motors: Axial flux motors equipped with the coreless stator of the high magnetic density and thin working area involved in this application achieve the best balance in terms of high efficiency, high power density and high reliability. They are especially suitable for cutting-edge application fields with extreme requirements for motor weight, size and performance, which greatly enhances the market competitiveness and application potential of coreless axial flux motors. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the coreless stator in the high magnetic flux density thin working region of this application.

[0030] Figure 2 for Figure 1 A cross-sectional schematic diagram.

[0031] Figure 3 for Figure 1 A schematic diagram of the structure of the first winding unit.

[0032] Figure 4 for Figure 3 A schematic diagram of the first winding unit when its outer and inner bridging regions are not bent.

[0033] Figure 5 for Figure 1 A schematic diagram of the structure of the second winding unit.

[0034] Figure 6 for Figure 5 A schematic diagram of the second winding unit when its outer and inner bridging areas are not bent.

[0035] Figure 7 This is a schematic diagram of the structure of a single-layer winding embodiment 1 in this application. The winding coil in the diagram is a hollow concentric line.

[0036] Figure 8 This is a schematic diagram of the structure of the second embodiment of the single-layer winding in this application. The winding coil in the figure is a single-unit distributed line type.

[0037] Figure 9 This is a wiring diagram of the first winding unit in an application example of a coreless stator with high magnetic flux density and thin working area in this application.

[0038] Figure 10 This is a wiring diagram of the second winding unit in an application example of a coreless stator with high magnetic flux density and thin working area in this application.

[0039] Figure 11 This is a structural schematic diagram of the single-stator dual-rotor configuration of the axial flux motor of this application.

[0040] Component labeling description: First winding unit 10, Second winding unit 20, Single layer winding 30, Winding coil 40, Working area 41, Outer ring bridging area 42, Inner ring bridging area 43, Hollow slot 44, Outer solder pad 45, Inner solder pad 46, Stator working part 51, Outer bridging end 52, Inner bridging end 53, Magnet mounting area 54, Insulation gap 60, Multi-turn concentric disc winding conductor ring 70, Concentric conductor ring 80, First rotor disk 91, Second rotor disk 92, Permanent magnet 93. Detailed Implementation

[0041] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0042] It should be understood that the structures, proportions, sizes, etc., depicted in the accompanying drawings are merely for illustrative purposes to aid those skilled in the art and to facilitate understanding. They are not intended to limit the scope of the invention and therefore have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effectiveness and objectives of the invention, should still fall within the scope of the technical content disclosed herein. Furthermore, the terms "upper," "lower," "left," "right," "middle," and "one" used in this specification are merely for clarity and not intended to limit the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention's implementation.

[0043] It should also be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on the other component or may be connected to an intermediary component. When a component is referred to as being "connected to" another component, it can be directly connected to the other component or indirectly connected to the other component through an intermediary component.

[0044] Furthermore, the use of terms such as "first" and "second" in this application is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed in this application.

[0045] This application relates to a coreless stator with a high magnetic flux density and a thin working area (hereinafter referred to as a coreless stator), and an axial flux motor including the coreless stator with the high magnetic flux density and thin working area. The axial flux motor adopts a single stator and dual rotor configuration. Furthermore, for ease of description, in the following embodiments, the axial direction of the motor shaft of the axial flux motor is defined as the left-right direction.

[0046] The axial flux motor involved in this application includes a motor housing, a motor shaft extending axially in the left-right direction, a first rotor disk 91, a second rotor disk 92, and a coreless stator; the motor shaft is rotatably mounted in the motor housing via bearings; as Figure 11 As shown, the first rotor disk 91 and the second rotor disk 92 are arranged opposite each other along the axial direction of the motor shaft. Both the first rotor disk 91 and the second rotor disk 92 are rotatably mounted in the motor housing and fixed to the outer periphery of the motor shaft. The coreless stator is assembled between the first rotor disk 91 and the second rotor disk 92. A first air gap is provided between the first rotor disk 91 and the coreless stator, and a second air gap is provided between the second rotor disk 92 and the coreless stator. The first air gap and the second air gap are the axial clearances. Thus, the coreless stator, the first rotor disk 91, and the second rotor disk 92 constitute a single-stator dual-rotor configuration of an axial flux motor. Both the first rotor disk 91 and the second rotor disk 92 include several circumferentially spaced permanent magnets 93. In the first rotor disk 91, the polarities of two circumferentially adjacent permanent magnets 93 are opposite, that is, the several permanent magnets 93 of the first rotor disk 91 are spaced apart in the manner of N pole, S pole, N pole, S pole, etc. In the second rotor disk 92, the polarities of two circumferentially adjacent permanent magnets 93 are opposite, that is, the several permanent magnets 93 of the second rotor disk 92 are spaced apart in the manner of N pole, S pole, N pole, S pole, etc. In the first rotor disk 91 and the second rotor disk 92, the polarities of two permanent magnets 93 that are directly opposite each other along the axial direction are opposite, that is, the N pole permanent magnet 93 of the first rotor disk 91 and the S pole permanent magnet 93 of the second rotor disk 92 are directly opposite each other, and the S pole permanent magnet 93 of the first rotor disk 91 and the N pole permanent magnet 93 of the second rotor disk 92 are directly opposite each other.

[0047] The coreless stator involved in this application is a coreless stator with high magnetic flux density and a thin working area. Specifically, as shown in the following example... Figure 1 and Figure 2 As shown, the coreless stator includes an axially stacked first winding unit 10 and a second winding unit 20, each of which includes at least one single-layer winding 30. Figure 3 and Figure 5 As shown, each single-layer winding 30 includes several winding coils 40. The several winding coils 40 of each single-layer winding 30 are processed on the same conductive substrate by a subtractive process. The several winding coils 40 are circumferentially spaced and independent of each other, without overlapping each other. There is a gap between two adjacent winding coils 40 formed by the subtractive process. In each single-layer winding 30, each winding coil 40 includes a working area 41 distributed in a radial plane, an outer ring bridging area 42 connected to the outer ring of the working area 41, an inner ring bridging area 43 connected to the inner ring of the working area 41, and a hollow slot 44 surrounded by the working area 41, the outer ring bridging area 42, and the inner ring bridging area 43. The hollow slot 44 is naturally formed after the subtractive process. The conductors of each part of the working area 41, the outer ring bridging area 42, and the inner ring bridging area 43 are connected end to end. Each winding coil 40 has an outer solder pad 45 and an inner solder pad 46 at its two ends, which are used for electrical connection of each winding coil 40. The working area 41 of the winding coil 40 is directly opposite the permanent magnet 93 of the rotor. Current flowing through the conductor of the working area 41 generates a magnetic field that drives the permanent magnet 93 to move. Continuous operation of the axial flux motor is achieved through reasonable commutation timing. In particular, in each single-layer winding 30, such as... Figure 3 and Figure 5 As shown, both the outer ring bridging area 42 and the inner ring bridging area 43 are bent in the same direction relative to the working area 41. Bending in the same direction means that the outer ring bridging area 42 and the inner ring bridging area 43 bend to the right or to the left simultaneously relative to the working area 41. Furthermore, the central angle α occupied by the adjacent working area 41 in two adjacent winding coils 40 is smaller than the central angle β occupied by the hollow slot 44 of a single winding coil 40.

[0048] When the first winding unit 10 and the second winding unit 20 are axially stacked, they are circumferentially misaligned; in other words, the first winding unit 10 and the second winding unit 20 are axially stacked in a circumferentially misaligned manner. Based on the unidirectional bending structure of the outer ring bridging area 42 and the inner ring bridging area 43 of several winding coils 40 in a single-layer winding 30, the structure of the hollow slot 44, and the setting that the central angle α occupied by the area adjacent to the working area 41 is smaller than the central angle β occupied by the hollow slot 44, it is achieved that when the first winding unit 10 and the second winding unit 20 are axially stacked in a circumferentially misaligned manner, as... Figure 1 and Figure 2As shown, the working area 41 of the winding coil 40 in the first winding unit 10 is embedded in the hollow slot 44 of the winding coil 40 in the second winding unit 20, and the working area 41 of the winding coil 40 in the second winding unit 20 is embedded in the hollow slot 44 of the winding coil 40 in the first winding unit 10, thereby circumferentially spacing the working areas 41 of the several winding coils 40 of the first winding unit 10 and the several winding coils 40 of the several winding coils 40 of the second winding unit 20. The windings are arranged and distributed in the same radial plane, forming the stator working section 51. The outer bridging regions 42 of the windings 40 of the first winding unit 10 and the outer bridging regions 42 of the windings 40 of the second winding unit 20 are axially stacked to form the outer bridging ends 52. The inner bridging regions 43 of the windings 40 of the first winding unit 10 and the inner bridging regions 43 of the windings 40 of the second winding unit 20 are axially stacked to form the inner bridging ends 53. Thus, in the coreless stator formed by the axial stacking of the first winding unit 10 and the second winding unit 20, as shown... Figure 2 As shown, it has a stator working section 51, an outer bridging end 52 connected to the outer periphery of the stator working area 41, and an inner bridging end 53 connected to the inner periphery of the stator working area 41. Since the stator working section 51 is formed by the circumferentially offset working areas 41 of the first winding unit 10 and the second winding unit 20, distributed in the same radial plane, the thickness of the stator working section 51 equals the thickness of the working area 41 of the first winding unit 10 equals the thickness of the working area 41 of the second winding unit 20. The outer bridging end 52 is formed by the outer ring bridging area 42 of the first winding unit 10 and the outer ring bridging area 42 of the second winding unit 20 stacked together axially, and the inner bridging end 53 is formed by the inner ring bridging area 43 of the first winding unit 10 and the inner ring bridging area 43 of the second winding unit 20. The coreless stator is formed by stacking 43 layers along the same axis, resulting in a minimum thickness at the stator working section 51. The stator working section 51 is the thinnest part of the coreless stator, effectively ensuring that the thickness of the stator working section 51 does not exceed half the total thickness of the coreless stator. Furthermore, magnet mounting areas 54 are formed on the outer end side, the inner circumference side of the outer bridging end 52, and the outer circumference side of the inner bridging end 53 of the stator working section 51. The permanent magnets 93 of the first rotor disk 91 and the second rotor disk 92 are rotatably mounted in the magnet mounting areas 54 of the coreless stator and are axially aligned with the stator working section 51 of the coreless stator. Therefore, the coreless stator of this application has the following beneficial effects.

[0049] 1. Enhanced air gap magnetic flux density, improving motor torque and power density: This application distributes the working areas 41 of the first winding unit 10 and the second winding unit 20 within the same radial plane, thereby further thinning the stator working portion 51 of the coreless stator. An innovative thinning design is implemented for the stator working portion 51 of the coreless stator, allowing a magnet mounting area 54 for accommodating the permanent magnet 93 to be formed on the outer side of the stator working portion 51. This enables the permanent magnet 93 to be closer to the stator working portion 51 of the coreless stator, directly and significantly reducing the effective working air gap length of the axial flux motor. According to basic electromagnetic principles, the air gap magnetic flux density is inversely proportional to the air gap length. Therefore, the reduction in the effective working air gap length in this application directly leads to a significant enhancement of the air gap magnetic flux density. In the electromagnetic design of the axial flux motor, the output torque is proportional to the square of the air gap magnetic flux density. Thus, with the same volume of axial flux motor and the amount of permanent magnet 93, this application enables the axial flux motor to output higher torque and power, significantly improving the torque density and power density of the motor, and solving the core bottleneck of the prior art caused by the thick stator working area 41, which results in excessive air gap and insufficient magnetic density.

[0050] 2. Achieving Synergistic Optimization of Performance and Reliability: This application does not simply reduce the overall thickness of the coreless stator, but rather adopts a "zonal design, function-oriented" approach. Extreme thinning is achieved in the working area 41 of the coreless stator to optimize electromagnetic performance. At the outer bridging end 52 and inner bridging end 53 of the coreless stator, the structure is strengthened through axial stacking of multi-layered bending structures to ensure the overall mechanical strength, rigidity, and heat dissipation capacity of the coreless stator. This application's coreless stator overcomes the limitations of traditional "uniform thickness" packaging schemes. While pursuing ultimate electromagnetic performance, it fundamentally ensures the long-term reliability of the coreless stator under high-speed rotation, electromagnetic force impact, and thermal cycling, resolving the inherent contradiction between thinning and strength.

[0051] 3. Expanded application prospects of axial flux motors: Axial flux motors equipped with the coreless stator of the high magnetic density and thin working area involved in this application achieve the best balance in terms of high efficiency, high power density and high reliability. They are especially suitable for cutting-edge application fields with extreme requirements for motor weight, size and performance, which greatly enhances the market competitiveness and application potential of coreless axial flux motors.

[0052] Furthermore, both the first winding unit 10 and the second winding unit 20 include several layers of single-layer windings 30. In the first winding unit 10, the outer ring bridging area 42 and the inner ring bridging area 43 of the several layers of single-layer windings 30 have the same bending direction. In the second winding unit 20, the outer ring bridging area 42 and the inner ring bridging area 43 of the several layers of single-layer windings 30 have the same bending direction. The bending direction of the outer ring bridging area 42 and the inner ring bridging area 43 of the first winding unit 10 is opposite to that of the outer ring bridging area 42 and the inner ring bridging area 43 of the second winding unit 20, so that the stator working part 51 has magnet mounting areas 54 on both ends in its thickness direction. Of course, it is also possible that the bending direction of the outer ring bridging area 42 and the inner ring bridging area 43 of the first winding unit 10 is the same as that of the outer ring bridging area 42 and the inner ring bridging area 43 of the second winding unit 20. Based on the different number of layers of the single-layer winding 30 in the first winding unit 10 and the second winding unit 20, as well as the different axial stacking structures of the first winding unit 10 and the second winding unit 20, there are multiple embodiments of the coreless stator.

[0053] Example 1 of the coreless stator: The coreless stator has a structure of 4 layers of single-layer windings 30. Two layers of single-layer windings 30 are stacked and packaged with each winding coil 40 aligned to form a first winding unit 10. The other two layers of single-layer windings 30 are stacked and packaged with each winding coil 40 aligned to form a second winding unit 20. The outer ring bridging area 42 and the inner ring bridging area 43 of each of the first winding unit 10 and the second winding unit 20 are bent to the left or both are bent to the right. After rotating one of the first winding unit 10 and the second winding unit 20 by a preset angle, the two are axially stacked and packaged to form a complete coreless stator. The thickness of the stator working part 51 is the thickness of two layers of working area 41.

[0054] Example 2 of coreless stator Figure 1 As shown, the coreless stator has a structure of four single-layer windings 30. Two of these single-layer windings 30 are stacked and packaged with their respective winding coils 40 aligned, as shown in the diagram. Figure 3 The first winding unit 10 shown has its outer ring bridging region 42 and inner ring bridging region 43 both bent to the right; the other two single-layer windings 30 are stacked and packaged with each winding coil 40 aligned as shown. Figure 5 The second winding unit 20 shown has its outer ring bridging area 42 and inner ring bridging area 43 both bent to the left; after rotating one of the first winding unit 10 and the second winding unit 20 by a preset angle, the two are axially stacked and packaged to form a complete coreless stator, and the thickness of the stator working part 51 is the thickness of two working areas 41.

[0055] Example 3 of the coreless stator: The coreless stator has an 8-layer single-layer winding 30 structure. Four layers of single-layer winding 30 are stacked and packaged with each winding coil 40 aligned to form a first winding unit 10. The outer ring bridging area 42 and inner ring bridging area 43 of the first winding unit 10 are both bent to the right. Another four layers of single-layer winding 30 are stacked and packaged with each winding coil 40 aligned to form a second winding unit 20. The outer ring bridging area 42 and inner ring bridging area 43 of the second winding unit 20 are both bent to the left. After rotating one of the first winding unit 10 and the second winding unit 20 by a preset angle, the two are axially stacked and packaged to form a complete coreless stator. That is, in this embodiment, four layers of single-layer winding 30 are used as one winding unit for rotation, and the thickness of the stator working section 51 is the thickness of four working sections 41.

[0056] Example 4 of the coreless stator: The coreless stator has an 8-layer single-layer winding 30 structure. Every two layers of single-layer winding 30 are stacked and packaged into a sub-unit with each winding coil 40 aligned, thus forming four sub-units. In two of these sub-units, the outer ring bridging area 42 and the inner ring bridging area 43 are bent to the left, and one of these two sub-units is rotated by a preset angle before being axially stacked and packaged. In the other two sub-units, the outer ring bridging area 42 and the inner ring bridging area 43 are bent to the right, and one of these two sub-units is rotated by a preset angle before being axially stacked and packaged. Finally, the two packaged sub-units are axially stacked and packaged to form a complete coreless stator. That is, in this embodiment, two layers of single-layer winding 30 are rotated as a winding unit, and the thickness of the stator working part 51 is still the thickness of 4 layers of working area 41.

[0057] Furthermore, by designing the bending angle, radius, and height of the outer ring bridging area 42 and the inner ring bridging area 43, each single-layer winding 30 is designed so that the two adjacent single-layer windings 30 of the first winding unit 10 and the two adjacent single-layer windings 30 of the second winding unit 20 have an insulation gap 60 after being stacked. That is, the conductors of the two adjacent single-layer windings 30 do not contact each other, and the two adjacent single-layer windings 30 are sealed and fixed by insulating glue filled in the insulation gap 60, thereby achieving interlayer insulation and sealing fixation.

[0058] Furthermore, the conductive substrate is a copper plate, an aluminum plate, or a silicon steel plate, and the subtractive processing method is laser etching; in this embodiment, the conductive substrate is a copper plate. When processing the single-layer winding 30, various winding line shapes can be formed by laser cutting along a specific path on a flat copper plate, and then aligned and stamped to obtain the single-layer winding 30; alternatively, various winding line shapes can be formed by laser cutting along a specific path on a pre-bent copper plate to directly obtain the single-layer winding 30. In addition, Figure 1In the second embodiment of the coreless stator shown, the bending degree of the outer ring bridging area 42 is greater than that of the inner ring bridging area 43. That is, more of the outer ring bridging area 42 is axially bent, while the inner ring bridging area 43 is axially bent and then extends straight radially. Thus, the working area 41 and the bending point of the inner ring bridging area 43 form a concave-convex structure. This structure is better suited for axial flux motors with an inner rotor structure. Conversely, in an axial flux motor with an outer rotor structure, in the configured coreless stator, the bending degree of the inner ring bridging area 43 is greater than that of the outer ring bridging area 42. More of the inner ring bridging area 43 is axially bent, while the outer ring bridging area 42 is axially bent and then extends straight radially. The working area 41 and the bending point of the outer ring bridging area 42 form a concave-convex structure.

[0059] Furthermore, in this embodiment, before laser cutting the copper plate, the design angle of the conductor in the working area 41 of the winding coil 40 is 10° on each side of the circumference, and the angle of the hollow slot 44 is designed to be 20°. After laser cutting, the actual angle of the hollow slot 44 is greater than 20°, and the actual angle of the conductor in the working area 41 on one side is less than 10°. This makes the actual angle of the working area 41 of the two connected winding coils 40 adjacent to each other less than 20°. When the first winding unit 10 and the second winding unit 20 are axially stacked, the rotation angle of one of them is 20°.

[0060] Furthermore, this application uses a laser to cut a copper plate along a specific path to form various winding profiles. The winding profiles of the winding coil 40 are preferably either hollow concentric or single-unit distributed.

[0061] The winding profile of coil 40 is a hollow concentric profile: such as... Figure 7 As shown, the winding coil 40 includes a multi-turn concentric coiled conductor ring 70 formed by a subtractive process. There are gaps between adjacent inner and outer turns of the multi-turn concentric coiled conductor ring 70 formed by the subtractive process. Each turn of the multi-turn concentric coiled conductor ring 70 is roughly rectangular, formed by four straight conductors connected end-to-end to create a hollow linear shape. The straight conductors on both circumferential sides constitute the working area 41. Therefore, the working area 41 includes several circumferentially parallel radial straight conductor segments, all extending radially. The outer ring bridging area 42 includes several radially parallel outer transition connection segments, all extending circumferentially. The inner ring bridging area 43 includes several radially parallel inner transition connection segments, all extending circumferentially. The radial straight conductor segments are connected to the outer transition connection segments, and the radial straight conductor segments are connected to the inner transition connection segments via arc segments.

[0062] The winding profile of winding coil 40 is a single-unit distributed profile: such as... Figure 8As shown, the winding coil 40 includes multiple concentric conductor rings 80 formed by a subtractive process. These concentric conductor rings 80 are arranged in an inner and outer loop, with gaps formed by the subtractive process between adjacent inner and outer rings 80. The straight conductors on both sides of each concentric conductor ring 80 constitute a working area 41. The working area 41 includes several circumferentially parallel radial straight conductor segments, each extending radially. Gaps formed by the subtractive process are provided between adjacent circumferentially adjacent radial straight conductor segments. The number and angle of laser cutting for the single-unit distributed linear winding coil 40 are calculated comprehensively based on the number of layers, slots, and turns.

[0063] Furthermore, in the coreless stator, the number of phases, turns, and series / parallel branches of the multi-layer single-layer winding 30 winding coil 40 are specifically designed based on electromagnetic performance. For example, Figure 3 and Figure 4 The first winding unit 10 shown, and Figure 5 and Figure 6 The second winding unit 20 shown is uniformly distributed with three phases A, B, and C. When the first winding unit 10 and the second winding unit 20 are axially superimposed, all three phases coincide, and the winding directions of the two layers of wire are consistent. Furthermore, in the first winding unit 10 and the second winding unit 20, as... Figures 3 to 6 As shown, each winding coil 40 has 4 turns. When the inner pad portion 46 of two aligned winding coils 40 in the two single-layer windings 30 of the first winding unit 10 is fixed by laser welding or soldering, the two aligned winding coils 40 are electrically connected, thereby continuously winding the two aligned winding coils 40 and forming a loop, with a total of 8 turns. Similarly, when the inner pad portion 46 of two aligned winding coils 40 in the two single-layer windings 30 of the second winding unit 20 is fixed by laser welding or soldering, the two aligned winding coils 40 are electrically connected, thereby continuously winding the two aligned winding coils 40 and forming a loop, with a total of 8 turns. The outer pad portion 45 of each winding coil 40 in the first winding unit 10 and the second winding unit 20 serves as the outer ring shorting point and lead wire according to the layer number requirement. In other embodiments, the inner pad portion 46 of the aligned winding coil 40 of the four single-layer winding 30 is laser-welded or soldered to form a 16-turn winding coil 40. Preferably, both the outer pad portion 45 and the inner pad portion 46 are rectangular pins.

[0064] The following provides an application example of the coreless stator of this application: the coreless stator has a 4-layer, 18-slot, 4-turn structure, and its electrical connection implementation path is as follows. For example... Figure 9 As shown, its first winding unit 10 forms 9 winding coils 40, corresponding to phases A, B, and C respectively; after mirroring and rotating the first winding unit 10 by 20°, the second winding unit 20 is obtained, as shown... Figure 10As shown, the second winding unit 20 also forms nine winding coils 40, corresponding to phases A, B, and C respectively. Each winding coil 40 is defined by a letter, coil position, and layer number; for example, A11 represents the first winding coil 40 in the first layer of phase A, A23 represents the second winding coil 40 in the third layer of phase A, and so on. + and - represent the direction of current. Figure 9 and Figure 10 As shown, the electrical connection begins at pin A11+, which serves as the first input pin. After the external input arrives, it flows along the wire to the inner coil solder joint, through the solder joints A11- and A12+, and then through the external lead to pin A23+. After arriving, it flows along the wire to the inner coil solder joint, through the solder joints A23- and A24+, and then through the solder joints A23- and A24+, and finally through the wire to pin A24-. The subsequent coils A3, A4, A5, and A6 complete the electrical connection of phase A using the same wiring sequence. Similarly, the remaining two sets of windings can be wound. The three-phase taps A- / B- / C- can be flexibly configured in either a delta or Y-type connection.

[0065] In summary, this invention effectively overcomes the various shortcomings of the prior art and has high industrial application value.

[0066] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A coreless stator with a high magnetic flux density and thin working area, characterized in that: It includes a first winding unit (10) and a second winding unit (20) stacked axially. The first winding unit (10) and the second winding unit (20) each include at least one single-layer winding (30). Each single-layer winding (30) includes several circumferentially spaced and mutually independent winding coils (40). Each single-layer winding (30) comprises several winding coils (40) fabricated on a conductive substrate using a subtractive process. Each winding coil (40) includes a working area (41) distributed in a radial plane, an outer ring bridging area (42) connecting the outer ring of the working area (41), an inner ring bridging area (43) connecting the inner ring of the working area (41), and a hollow slot (44) formed by the working area (41), the outer ring bridging area (42), and the inner ring bridging area (43). The conductor ends of the winding coil (40) are respectively the outer solder pad (45) and the inner solder pad (46). The working area (41) is used to face the permanent magnet (93) of the rotor in the axial flux motor. The outer ring bridging area (42) and the inner ring bridging area (43) are bent in the same direction relative to the working area (41). The central angle occupied by the adjacent working area (41) of two adjacent winding coils (40) is smaller than the central angle occupied by the hollow slot (44) of a single winding coil (40). When the first winding unit (10) and the second winding unit (20) are stacked axially, they are circumferentially misaligned. The working area (41) of the winding coil (40) in the first winding unit (10) is embedded in the hollow slot (44) of the winding coil (40) in the second winding unit (20). The working area (41) of the winding coil (40) in the second winding unit (20) is embedded in the hollow slot (44) of the winding coil (40) in the first winding unit (10). This makes the working areas (41) of several winding coils (40) in the first winding unit (10) and the working areas (41) of several winding coils (40) in the second winding unit (20) circumferentially spaced and distributed in the same radial plane, forming a stator working part (51). The thickness of part (51) does not exceed 1 / 2 of the total thickness of the coreless stator. The outer ring bridging area (42) of several winding coils (40) of the first winding unit (10) and the outer ring bridging area (42) of several winding coils (40) of the second winding unit (20) are axially stacked to form an outer bridging end (52). The inner ring bridging area (43) of several winding coils (40) of the first winding unit (10) and the inner ring bridging area (43) of several winding coils (40) of the second winding unit (20) are axially stacked to form an inner bridging end (53). The outer end side of the stator working part (51), the inner peripheral side of the outer bridging end (52) and the outer peripheral side of the inner bridging end (53) are formed with magnet mounting areas (54) for accommodating permanent magnets (93) of the rotor.

2. The coreless stator with high magnetic flux density and thin working area according to claim 1, characterized in that: The first winding unit (10) and the second winding unit (20) both include several layers of single-layer windings (30); In the first winding unit (10), the outer ring bridging area (42) and the inner ring bridging area (43) of the multi-layer single-layer winding (30) have the same bending direction; In the second winding unit (20), the outer ring bridging area (42) and the inner ring bridging area (43) of the multi-layer single-layer winding (30) have the same bending direction; The bending directions of the outer ring bridging area (42) and the inner ring bridging area (43) of the first winding unit (10) are opposite to the bending directions of the outer ring bridging area (42) and the inner ring bridging area (43) of the second winding unit (20), so that the stator working part (51) has magnet mounting areas (54) on both ends in its thickness direction.

3. The coreless stator with high magnetic flux density and thin working area according to claim 1, characterized in that: The first winding unit (10) and the second winding unit (20) both include several layers of single-layer windings (30); In the first winding unit (10), several winding coils (40) of several single-layer windings (30) are aligned one by one. The inner pad portion (46) of the several aligned winding coils (40) in the several single-layer windings (30) is electrically connected, so that the several aligned winding coils (40) are continuously wound and form a circuit. In the second winding unit (20), several winding coils (40) of several single-layer windings (30) are aligned one by one. The inner pad portion (46) of the several aligned winding coils (40) in the several single-layer windings (30) is electrically connected, so that the several aligned winding coils (40) are continuously wound and form a circuit.

4. The coreless stator with high magnetic flux density and thin working area according to claim 3, characterized in that: The inner pads (46) of several aligned winding coils (40) are aligned and fixed by laser welding or soldering.

5. The coreless stator with high magnetic flux density and thin working area according to claim 1, characterized in that: The first winding unit (10) and the second winding unit (20) both include several layers of single-layer windings (30); The first winding unit (10) has an insulation gap (60) between two adjacent single-layer windings (30) and the second winding unit (20) has an insulation gap (60) between two adjacent single-layer windings (30), and the insulation gap (60) is sealed and fixed by insulating glue filled in the insulation gap (60).

6. The coreless stator with high magnetic flux density and thin working area according to claim 1, characterized in that: The working area (41) includes several radially straight conductor segments arranged side by side in the circumferential direction and all extending in the radial direction. A gap formed by a subtractive process is provided between two adjacent radially straight conductor segments in the circumferential direction.

7. The coreless stator with high magnetic flux density and thin working area according to claim 6, characterized in that: The winding coil (40) has a hollow concentric winding shape, including a multi-turn concentric coiled conductor ring (70) formed by a material reduction process. The multi-turn concentric coiled conductor ring (70) has gaps formed by a material reduction process between adjacent inner and outer rings. The outer ring bridging area (42) includes several radially parallel outer transition connection sections that extend circumferentially. The inner ring bridging area (43) includes several radially parallel inner transition connection sections that extend circumferentially. The radial straight conductor section is connected to the outer transition connection section and the radial straight conductor section is connected to the inner transition connection section by arc segments.

8. The coreless stator with high magnetic flux density and thin working area according to claim 6, characterized in that: The winding coil (40) has a single-unit distribution winding shape, including multiple concentric conductor rings (80) formed by the subtraction process. The multiple concentric conductor rings (80) are arranged inside and outside each other, and there is a gap formed by the subtraction process between adjacent inner and outer concentric conductor rings (80).

9. The coreless stator with high magnetic flux density and thin working area according to claim 1, characterized in that: The conductive substrate is a copper plate, an aluminum plate, or a silicon steel plate, and the subtractive material process is laser etching.

10. An axial flux motor, comprising a motor housing, a motor shaft rotatably mounted in the motor housing, and a first rotor disk (91) and a second rotor disk (92) rotatably mounted in the motor housing and fixed to the outer periphery of the motor shaft, wherein the first rotor disk (91) and the second rotor disk (92) each include a plurality of circumferentially spaced permanent magnets (93), wherein the polarities of two circumferentially adjacent permanent magnets (93) and two axially opposite permanent magnets (93) are opposite, characterized in that: It also includes the coreless stator with a high magnetic density thin working area as described in any one of claims 1-9, wherein the coreless stator with a high magnetic density thin working area is assembled between the first rotor disk (91) and the second rotor disk (92), wherein the permanent magnets (93) of the first rotor disk (91) and the second rotor disk (92) are rotatably assembled in the magnet mounting area (54) of the coreless stator and are axially aligned with the stator working part (51) of the coreless stator.

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