Coreless stator with high flux density and thin working area and axial flux motor

Abstract

The invention provides a coreless stator with a high flux density thin working area and an axial flux motor, the coreless stator comprises a first winding unit and a second winding unit which are axially laminated, and a plurality of winding coils of the first winding unit and the second winding unit are processed on a conductive substrate through a material reduction technology. Each winding coil comprises a working area, a hollow groove, a bent outer ring bridging area and a bent inner ring bridging area, and the first winding unit and the second winding unit are circumferentially staggered when being axially stacked, so that the working areas of the first winding unit and the second winding unit are circumferentially arranged at intervals and are distributed in the same radial plane to form a stator working part; and the thickness of the stator working part does not exceed 1 / 2 of the total thickness of the coreless stator. According to the axial flux motor, the stator working part of the coreless stator is further thinned, the effective working air gap length of the axial flux motor is remarkably reduced, the air gap flux density is remarkably enhanced, the torque density and the power density of the motor are improved, and collaborative optimization of performance and reliability is achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electric machines, in particular to a high-magnetic-density thin working area coreless stator and axial flux motor. BACKGROUND

[0002] At present, the axial flux motor with a coreless stator is widely concerned in the fields of electric transportation, industrial driving and aerospace, etc. which are extremely sensitive to space and weight, due to its disc structure, short axial size, high power / torque density and other advantages. The axial flux motor with a single stator and double rotors has the advantages of symmetrical magnetic circuit, high torque density and potential of no iron loss of the stator, and is an ideal choice to realize ultra-high power density.

[0003] It is well known that the air gap length of the motor is one of the core parameters affecting its performance. The air gap flux density is approximately inversely proportional to the air gap length, and the smaller the air gap length, the greater the flux density. In theory, in order to obtain a stronger air gap magnetic field and higher electromagnetic force, the air gap length should be as small as possible. However, in the axial flux motor with a single stator and double rotors, the physical air gap is determined by the axial distance between the surface of the permanent magnet of the rotor part and the working surface of the stator. However, the coreless stator itself needs to have sufficient structural thickness (including winding, insulation, packaging material, etc.) 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 air gap that can be achieved by the axial flux motor.

[0004] In the existing manufacturing process of the coreless stator, a single layer winding is first made by laser engraving a copper plate, and then a plurality of single layer windings are stacked axially and packaged into a composite material plate with a uniform thickness. The final thickness depends on the sum of the number of layers and the thickness of the interlayer insulation material. Obviously, the existing manufacturing process is simple and structurally sound, but it does not distinguish between functional areas of the stator, so the working area and the non-working area (referring to the inner and outer cross-over areas) of the stator use the same thickness and material standard, which is not optimal in structure. The overall thickness of the working area of the stator is ultimately limited by the overall thickness of the coreless stator maintained to ensure the strength of the non-working area, which hinders the performance improvement of the working area, resulting in a thicker overall thickness of the working area of the stator, which is difficult to further thin, thereby limiting the reduction of the air gap of the axial flux motor, resulting in a reduction in the magnetic flux density of the axial flux motor due to the limited air gap length. SUMMARY

[0005] In view of the above-mentioned shortcomings of the prior art, the purpose of the present application is to provide a coreless stator with a high magnetic density and a thin working area, which further thins the working area of the coreless stator and enhances the magnetic flux density.

[0006] To achieve the above object, the application provides a coreless stator of high magnetic density and thin working area, comprising axially laminated first winding unit and second winding unit, the first winding unit and the second winding unit both comprise at least one single-layer winding, each single-layer winding comprises a plurality of winding coils which are distributed in a circumferential direction and independent of each other;

[0007] The plurality of winding coils of each single-layer winding are processed on a conductive substrate by subtractive process, each winding coil comprises a working area distributed in a radial plane, an outer cross-connection area connected to an outer ring of the working area, an inner cross-connection area connected to an inner ring of the working area, and a hollow slot surrounded by the working area, the outer cross-connection area and the inner cross-connection area, the two ends of the conductor of each winding coil are respectively an outer pad part and an inner pad part, the working area is used for the permanent magnet of the rotor in the axial flux motor, the outer cross-connection area and the inner cross-connection area are bent in the same direction relative to the working area, and the central angle of the working area of the two adjacent winding coils is smaller than the central angle of the hollow slot of a single winding coil.

[0008] The first winding unit and the second winding unit are axially laminated and circumferentially staggered, 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, so that the working areas of the plurality of winding coils of the first winding unit and the working areas of the plurality of winding coils of the second winding unit are circumferentially spaced and distributed in the same radial plane, and form a stator working part, the thickness of the stator working part does not exceed 1 / 2 of the total thickness of the coreless stator, the outer cross-connection areas of the plurality of winding coils of the first winding unit and the outer cross-connection areas of the plurality of winding coils of the second winding unit are axially laminated to form an outer cross-connection end part, and the inner cross-connection areas of the plurality of winding coils of the first winding unit and the inner cross-connection areas of the plurality of winding coils of the second winding unit are axially laminated to form an inner cross-connection end part, and the outer end side of the stator working part, the inner circumferential side of the outer cross-connection end part and the outer circumferential side of the inner cross-connection end part form a magnet mounting area for accommodating the permanent magnet of the rotor.

[0009] Further, the first winding unit and the second winding unit both comprise a plurality of single-layer windings;

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

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

[0012] The bending direction of the outer ring cross-bridge area and the inner ring cross-bridge area of the first winding unit is opposite to the bending direction of the outer ring cross-bridge area and the inner ring cross-bridge area of the second winding unit, so that the stator working part has a magnet mounting area on both ends in the thickness direction.

[0013] Further, the first winding unit and the second winding unit both include a plurality of single-layer windings;

[0014] In the first winding unit, a plurality of winding coils of the plurality of single-layer windings are aligned one by one, and the inner pad portions of the plurality of winding coils aligned in the plurality of single-layer windings are electrically connected to continuously wind and form a loop.

[0015] In the second winding unit, a plurality of winding coils of the plurality of single-layer windings are aligned one by one, and the inner pad portions of the plurality of winding coils aligned in the plurality of single-layer windings are electrically connected to continuously wind and form a loop.

[0016] Further, the inner pad portions of the plurality of aligned winding coils are aligned and fixed by laser welding or soldering.

[0017] Further, the first winding unit and the second winding unit both include a plurality of single-layer windings;

[0018] The first winding unit and the second winding unit both include a plurality of single-layer windings;

[0019] Further, the working area includes a plurality of circumferentially arranged and radially extending radial straight conductor segments, and gaps formed by subtractive processing are arranged between two circumferentially adjacent radial straight conductor segments.

[0020] Further, the winding wire type of the winding coil is a hollow concentric wire type, including a plurality of concentric coil-shaped conductor rings formed by subtractive processing.

[0021] The plurality of concentric coil-shaped conductor rings have gaps formed by subtractive processing between adjacent inner and outer rings, the outer ring cross-bridge area includes a plurality of radially arranged and circumferentially extending outer transition connection segments, the inner ring cross-bridge area includes a plurality of radially arranged and circumferentially extending inner transition connection segments, and the radial straight conductor segments and the outer transition connection segments, and the radial straight conductor segments and the inner transition connection segments are connected by arc segments.

[0022] Further, the winding wire type of the winding coil is a single distributed wire type, including a plurality of concentric conductor rings formed by subtractive processing, and the plurality of concentric conductor rings are arranged in a nested manner, and gaps formed by subtractive processing are arranged between adjacent inner and outer rings.

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

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

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

[0026] 1. Enhancing air gap magnetic density and improving motor torque and power density: By setting the outer coil crossover area and the inner coil crossover area of a plurality of winding coils in a single layer winding to a structure that bends in the same direction relative to the working area, and by setting the hollow slot of each winding coil, when the first winding unit and the second winding unit are axially stacked in a circumferentially staggered manner, the working area of the first winding unit and the second winding unit can be distributed in the same radial plane, thereby further thinning the stator working part of the coreless stator, and forming a magnet mounting area on the outside of the stator working part of the coreless stator to accommodate the permanent magnets, thereby significantly reducing the effective working air gap length of the axial flux motor. The reduction of the effective working air gap length directly leads to the significant enhancement of the air gap magnetic density. In the electromagnetic design of the axial flux motor, the output torque is proportional to the square of the air gap magnetic density. Therefore, under the same volume and amount of permanent magnets of the axial flux motor, the application can output higher torque and power, greatly improving the torque density and power density of the motor, and solving the core bottleneck of the prior art that the thickness of the stator working area is relatively thick, resulting in a large air gap and insufficient magnetic density.

[0027] 2. Synergistic optimization of performance and reliability: instead of simply reducing the thickness of the coreless stator as a whole, the application realizes the ultimate reduction in the working area of the coreless stator in a "zoned design, function-oriented" manner to optimize electromagnetic performance; at the outer and inner cross-connection end portions of the coreless stator, the axial stacking of the multi-layer bending structure is used to strengthen the structure to ensure the overall mechanical strength, rigidity and heat dissipation capacity of the coreless stator. The coreless stator of the application breaks through the limitations of the traditional "uniform thickness" packaging scheme, while pursuing the ultimate electromagnetic performance, it fundamentally guarantees the long-term operation reliability of the coreless stator under high-speed rotation, electromagnetic force impact and thermal cycling, and solves the inherent contradiction between thinning and strength.

[0028] 3. Expanding the application prospects of axial flux motors: the axial flux motor equipped with the coreless stator with high magnetic density thin working area of the application realizes the best balance in terms of high efficiency, high power density and high reliability, and is especially suitable for cutting-edge application fields with extreme requirements for the weight, size and performance of the motor, greatly enhancing the market competitiveness and application potential of coreless axial flux motors. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 is a structural schematic diagram of the coreless stator with high magnetic density thin working area of the application.

[0030] Figure 2 is a cross-sectional schematic diagram of Figure 1

[0031] Figure 3 is a structural schematic diagram of the first winding unit in Figure 1

[0032] Figure 4 is a schematic diagram of the first winding unit in Figure 3 its outer ring cross-connection area and inner ring cross-connection area without bending.

[0033] Figure 5 is a structural schematic diagram of the second winding unit in Figure 1

[0034] Figure 6 is a schematic diagram of the second winding unit in Figure 5 its outer ring cross-connection area and inner ring cross-connection area without bending.

[0035] Figure 7 is a structural schematic diagram of the single-layer winding embodiment one in the application, and the winding coil in the diagram is a hollow concentric wire type.

[0036] Figure 8 is a structural schematic diagram of the single-layer winding embodiment two in the application, and the winding coil in the diagram is a single-body distributed wire type. ​​​

[0037] Figure 9 Fig. 1 is a schematic diagram of the connection of the first winding unit in an application example of the high-flux-thin working area coreless stator of the present application.

[0038] Figure 10 Fig. 2 is a schematic diagram of the connection of the second winding unit in an application example of the high-flux-thin working area coreless stator of the present application.

[0039] Figure 11 Fig. 3 is a schematic diagram of the structure of the single-stator double-rotor configuration of the axial flux motor of the present application.

[0040] Element No. Explanation First winding unit 10, second winding unit 20, single-layer winding 30, winding coil 40, working area 41, outer ring crossover area 42, inner ring crossover area 43, hollow slot 44, outer pad portion 45, inner pad portion 46, stator working portion 51, outer crossover end portion 52, inner crossover end portion 53, magnet mounting area 54, insulation distance 60, multi-coil concentric disc winding conductor ring 70, concentric conductor ring 80, first rotor disc 91, second rotor disc 92, permanent magnet 93. DETAILED DESCRIPTION

[0041] The embodiments of the present application will be described in detail by the following specific examples, and other advantages and effects of the present application can be easily understood by those skilled in the art from the contents disclosed in the specification.

[0042] It should be noted that the structures, proportions, sizes, etc. shown in the drawings of the specification are only used to cooperate with the contents disclosed in the specification for understanding and reading by those skilled in the art, and are not used to limit the conditions that the present application can be implemented, and therefore do not have technical substantive significance. Any modification of the structure, change of the proportional relationship, or adjustment of the size, without affecting the effects that the present application can produce and the purposes that the present application can achieve, should still fall within the scope of the technical content disclosed by the present application. At the same time, the terms such as "upper", "lower", "left", "right", "middle", and "one" used in the specification are only for the convenience of clear description, and are not used to limit the scope of the present application that can be implemented, and the change or adjustment of the relative relationship, without substantially changing the technical content, is also considered as the scope of the present application that can be implemented.

[0043] It should also be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or can have a middle element present. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or can be indirectly connected to the other element through a middle element.

[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 zones 41 of the winding coils 40 in the first winding unit 10 are embedded in the hollow slots 44 of the winding coils 40 in the second winding unit 20, and the working zones 41 of the winding coils 40 in the second winding unit 20 are embedded in the hollow slots 44 of the winding coils 40 in the first winding unit 10, so that the working zones 41 of the winding coils 40 in the first winding unit 10 and the working zones 41 of the winding coils 40 in the second winding unit 20 are circumferentially spaced and distributed in the same radial plane to form the stator working part 51, and the outer cross-over zones 42 of the winding coils 40 in the first winding unit 10 and the outer cross-over zones 42 of the winding coils 40 in the second winding unit 20 are axially stacked to form the outer cross-over end part 52, and the inner cross-over zones 43 of the winding coils 40 in the first winding unit 10 and the inner cross-over zones 43 of the winding coils 40 in the second winding unit 20 are axially stacked to form the inner cross-over end part 53. In this way, the first winding unit 10 and the second winding unit 20 are axially stacked to form the coreless stator, which has the stator working part 51, the outer cross-over end part 52 connected to the outer periphery of the stator working part 41, and the inner cross-over end part 53 connected to the inner periphery of the stator working part 41. Figure 2 As shown, the working zones 41 of the winding coils 40 in the first winding unit 10 are embedded in the hollow slots 44 of the winding coils 40 in the second winding unit 20, and the working zones 41 of the winding coils 40 in the second winding unit 20 are embedded in the hollow slots 44 of the winding coils 40 in the first winding unit 10, so that the working zones 41 of the winding coils 40 in the first winding unit 10 and the working zones 41 of the winding coils 40 in the second winding unit 20 are circumferentially spaced and distributed in the same radial plane to form the stator working part 51, and the outer cross-over zones 42 of the winding coils 40 in the first winding unit 10 and the outer cross-over zones 42 of the winding coils 40 in the second winding unit 20 are axially stacked to form the outer cross-over end part 52, and the inner cross-over zones 43 of the winding coils 40 in the first winding unit 10 and the inner cross-over zones 43 of the winding coils 40 in the second winding unit 20 are axially stacked to form the inner cross-over end part 53. In this way, the first winding unit 10 and the second winding unit 20 are axially stacked to form the coreless stator, which has the stator working part 51, the outer cross-over end part 52 connected to the outer periphery of the stator working part 41, and the inner cross-over end part 53 connected to the inner periphery of the stator working part 41.

[0049] 1. Enhance the air gap magnetic flux density, improve the motor torque and power density: the application makes the working area 41 of the first winding unit 10 and the working area 41 of the second winding unit 20 distributed in the same radial plane, thereby further thinning the stator working part 51 of the coreless stator, innovatively thinning the design of the stator working part 51 of the coreless stator, and enabling the coreless stator to form a magnet mounting area 54 accommodating the permanent magnet 93 outside the stator working part 51, so that the permanent magnet 93 can be closer to the stator working part 51 of the coreless stator, thereby directly and significantly reducing the effective working air gap length of the axial flux motor. According to the basic principle of electromagnetism, the air gap magnetic induction intensity is inversely proportional to the air gap length. Therefore, the reduction of the effective working air gap length in the application directly leads to the 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. Therefore, under the same volume and amount of permanent magnet 93 of the axial flux motor, the application can output higher torque and power of the axial flux motor, greatly improving the torque density and power density of the motor, and solving the core bottleneck of the prior art that the thickness of the stator working area 41 is too thick, resulting in too large air gap and insufficient magnetic flux density.

[0050] 2. Achieve the synergistic optimization of performance and reliability: instead of simply thinning the coreless stator as a whole, the application realizes extreme thinning in the working area 41 of the coreless stator in a "partition design, function-oriented" manner to optimize electromagnetic performance; in the outer cross-connection end part 52 and the inner cross-connection end part 53 of the coreless stator, the axial stacking of the multi-layer bending structure is used to strengthen the structure to ensure the overall mechanical strength, rigidity and heat dissipation capacity of the coreless stator. The coreless stator of the application breaks through the limitations of the traditional "uniform thickness" packaging scheme, while pursuing the ultimate electromagnetic performance, fundamentally guarantees the long-term operation reliability of the coreless stator under high-speed rotation, electromagnetic force impact and thermal cycle, and solves the inherent contradiction between thinning and strength.

[0051] 3. Expand the application prospect of the axial flux motor: the axial flux motor equipped with the coreless stator with high magnetic flux density and thin working area according to the application achieves the best balance in terms of high efficiency, high power density and high reliability, and is especially suitable for the application of extreme requirements on the weight, volume and performance of the motor, greatly enhancing the market competitiveness and application potential of the coreless axial flux motor.

[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] The coreless stator of the third embodiment is structured by eight layers of single-layer windings 30. Four layers of single-layer windings 30 are stacked in a manner that the winding coils 40 are aligned to form a first winding unit 10, and the outer crossover area 42 and the inner crossover area 43 of the first winding unit 10 are bent to the right. Another four layers of single-layer windings 30 are stacked in a manner that the winding coils 40 are aligned to form a second winding unit 20, and the outer crossover area 42 and the inner crossover area 43 of the second winding unit 20 are bent to the left. One of the first winding unit 10 and the second winding unit 20 is rotated by a preset angle, and then the two are stacked axially to form a complete coreless stator. In this embodiment, four layers of single-layer windings 30 are rotated as a winding unit, and the thickness of the stator working part 51 is the thickness of four layers of working areas 41.

[0056] The coreless stator of the fourth embodiment is structured by eight layers of single-layer windings 30. Two layers of single-layer windings 30 are stacked in a manner that the winding coils 40 are aligned to form a sub-unit, and then four sub-units are formed. The outer crossover area 42 and the inner crossover area 43 of two sub-units are bent to the left, and one of the two sub-units is rotated by a preset angle, and then the two are stacked axially. The outer crossover area 42 and the inner crossover area 43 of another two sub-units are bent to the right, and one of the two sub-units is rotated by a preset angle, and then the two are stacked axially. Finally, the two stacked sub-units are stacked axially to form a complete coreless stator. In this embodiment, two layers of single-layer windings 30 are rotated as a winding unit, and the thickness of the stator working part 51 is still the thickness of four layers of working areas 41.

[0057] Further, the bending angle, radius, and height of the outer crossover area 42 and the inner crossover area 43 are designed for each layer of single-layer windings 30, so that the adjacent two layers of single-layer windings 30 of the first winding unit 10 have an insulation spacing 60 after being stacked, and the adjacent two layers of single-layer windings 30 of the second winding unit 20 also have an insulation spacing 60 after being stacked. That is, the conductors of the adjacent two layers of single-layer windings 30 do not contact each other, and the adjacent two layers of single-layer windings 30 are fixed by the insulating glue filled in the insulation spacing 60, realizing insulation and fixation between layers.

[0058] Further, the conductive substrate is a copper plate, or an aluminum plate, or a silicon steel plate, and the subtractive process is laser etching. In this embodiment, the conductive substrate is a copper plate. When processing the single-layer winding 30, a plurality of winding lines can be formed on the copper plate in a flat plate structure by laser cutting according to a specific path, and then the single-layer winding 30 can be obtained by aligning and stamping. Alternatively, the single-layer winding 30 can be directly obtained by cutting a plurality of winding lines on a pre-bent copper plate according to a specific path. In addition, Figure 1In the second embodiment of the coreless stator shown, the bending degree of the outer ring cross-over region 42 is greater than that of the inner ring cross-over region 43, i.e. more parts of the outer ring cross-over region 42 are bent axially, while the inner ring cross-over region 43 is bent axially and then extends flat in the radial direction, so that the working region 41 and the bending part of the inner ring cross-over region 43 form a concave-convex structure, which is more suitable for an axial flux motor with an inner rotor structure. Conversely, in an axial flux motor with an outer rotor structure, the coreless stator is configured such that the bending degree of the inner ring cross-over region 43 is greater than that of the outer ring cross-over region 42, i.e. more parts of the inner ring cross-over region 43 are bent axially, while the outer ring cross-over region 42 is bent axially and then extends flat in the radial direction, so that the working region 41 and the bending part of the outer ring cross-over region 42 form a concave-convex structure.

[0059] In addition, in this embodiment, before the copper plate is laser cut, the design angle of the conductor of the working region 41 of the winding coil 40 is 10° on each of the circumferential sides, and the angle of the hollow slot 44 is designed to be 20°, so that after laser cutting, the actual angle of the hollow slot 44 is greater than 20°, and the actual angle of the conductor of the single working region 41 is less than 10°, so that the actual angle of the working region 41 of the two winding coils 40 connected in close proximity is less than 20°, and 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] Further, the copper plate is cut by laser according to a specific path to form various winding line types, and the winding line type of the winding coil 40 is preferably one of a hollow concentric line type and a single body distributed line type.

[0061] The winding line type of the winding coil 40 is a hollow concentric line type: as shown in Figure 7 The winding coil 40 includes a plurality of concentric coil-shaped conductor rings 70 formed after a subtractive process, and the adjacent inner and outer rings of the plurality of concentric coil-shaped conductor rings 70 have gaps formed after the subtractive process, and a single ring of the plurality of concentric coil-shaped conductor rings 70 is in a rectangular shape, and the four straight conductors are connected end to end to form a hollow line type, and the straight conductors on the circumferential sides constitute the working region 41. Therefore, the working region 41 includes a plurality of radial straight conductor segments arranged side by side in the circumferential direction and extending in the radial direction, the outer ring cross-over region 42 includes a plurality of outer transition connection segments arranged side by side in the radial direction and extending in the circumferential direction, the inner ring cross-over region 43 includes a plurality of inner transition connection segments arranged side by side in the radial direction and extending in the circumferential direction, and the radial straight conductor segments and the outer transition connection segments, and the radial straight conductor segments and the inner transition connection segments are connected by arc segments.

[0062] The winding line type of the winding coil 40 is a single body distributed line type: as shown in 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 9 winding coils 40, corresponding to three phases A, B and C respectively. Each winding coil 40 is defined by a letter, a coil position and a layer number, such as A11 representing the winding coil 40 of the first coil of the first layer of the phase A, A23 representing the winding coil 40 of the second coil of the third layer of the phase A, and so on. "+" and "-" represent the direction of current. Figure 9 and Figure 10 As shown, the starting end of the electrical connection is the A11+ pin, which is the first input pin. After the external input, the wire enters the inner circle welding point, passes through the A11- and A12+ welding points, reaches the A12- pin, and then passes through the external lead to the A23+ pin. After the input, the wire enters the inner circle welding point, passes through the A23- and A24+ welding points, reaches the A24- pin, and then the subsequent A3, A4, A5 and A6 coils complete the electrical connection of the phase A through the same wiring sequence. Similarly, the remaining two groups of winding can be wound, and the three-phase taps A- / B- / C- can be flexibly changed to delta connection or Y connection.

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

[0066] The above embodiments only exemplarily illustrate the principles and effects of the present application, and are not used to limit the present application. Any person skilled in the art can modify or change the above embodiments without departing from the spirit and scope of the present application. Therefore, all equivalent modifications or changes completed by those skilled in the art without departing from the spirit and technical thought of the present application should be covered by the claims of the present application.

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.

Images