Stator and electromagnetic structure

Abstract

The invention relates to the technical field of motors, in particular to a stator and an electromagnetic structure, the stator is used for being arranged at an interval with a rotor along the central axis of an output shaft so as to drive the rotor to drive the output shaft to rotate, and the stator comprises a stator substrate and a driving coil arranged on the stator substrate, the driving coil comprises two electrified coils, the two electrified coils are periodically bent and extend in the circumferential direction of the central axis, and the two electrified coils are arranged in a staggered mode in the circumferential direction of the central axis and do not intersect with each other so as to form a plurality of magnetic flux areas arranged in the circumferential direction. By adopting the technical scheme, the stator structure is highly integrated, so that the axial size of the motor is smaller, and the performance is more reliable.

Description

Technical Field

[0001] The present disclosure relates to the technical field of motors, and in particular, to a stator and an electromagnetic structure. Background Art

[0002] The axial flux motor is also called a disc motor, that is, a motor whose main magnetic field is along the axis of the rotating shaft. It has a compact structure, light weight, high power density and torque density. As a result, the axial flux motor is used in more fields such as electric vehicles, drones and industrial equipment.

[0003] In the related art, the axial flux motor includes a fixed stator and a rotating rotor. The stator is a winding coil arranged on a flat substrate, and the rotor includes a permanent magnet. During the operation of the axial flux motor, the current in the winding coil generates a magnetic field, and then the rotor rotates through the coupling magnetic field between the winding coil and the rotor. However, due to the large axial size of the winding and the high manufacturing cost, it is difficult to apply it to an axially flat space. Summary of the invention

[0004] The purpose of the present disclosure is to provide a stator and electromagnetic structure, which is highly integrated and can make the axial size of the motor smaller and the performance more reliable, so as to at least partially solve the above technical problems.

[0005] In order to achieve the above object, according to a first aspect of the present disclosure, a stator is provided, which is arranged at intervals with a rotor along the central axis of an output shaft to drive the rotor to rotate the output shaft, and the stator includes:

[0006] a stator base plate; and

[0007] The driving coil is arranged on the stator substrate, and the driving coil includes two energized coils. The two energized coils are each periodically bent and extended along the circumferential direction of the central axis. The two energized coils are staggered and non-intersecting along the circumferential direction of the central axis to form a plurality of magnetic flux areas arranged along the circumferential direction.

[0008] Optionally, the stator substrate has a first side surface and a second side surface opposite to each other along the central axis, and the energized coil includes a plurality of first portions exposed on the first side surface and a plurality of second portions exposed on the second side surface, and the plurality of first portions and the plurality of second portions are alternately connected in sequence along the circumferential direction between the input end and the output end of the energized coil.

[0009] Optionally, the first portion and the second portion are connected via a first connecting portion passing through a first via hole on the stator substrate.

[0010] Optionally, the first side surface of the stator substrate faces the rotor, and the second portion is configured as or connected to a heat dissipation structure.

[0011] Optionally, the second portion is configured as a plate-shaped heat dissipation structure.

[0012] Optionally, the stator further comprises a sensing coil, wherein the sensing coil is arranged on the stator substrate around the central axis, the sensing coil is radially located inside or outside the driving coil, and the sensing coil is used to indirectly detect the rotation speed of the output shaft by detecting an induced voltage.

[0013] Optionally, the sensing coil has a plurality of first units located on a first side surface of the stator substrate and arranged along the circumferential direction, and a plurality of second units located on a second side surface of the stator substrate and arranged along the circumferential direction, the first units and the second units are both arranged in a spiral shape, the sensing coil is connected to the stator substrate by via connection, and is constructed so that the rotation direction of the current flowing through the first unit is the same as the rotation direction of the current flowing through the second unit located opposite to the first unit on the central axis, and the rotation directions of the current flowing through two adjacent first units are opposite, and the rotation directions of the current flowing through two adjacent second units are opposite.

[0014] According to a second aspect of the present disclosure, an electromagnetic structure is provided, comprising a rotor and a stator assembly, wherein the stator assembly is arranged on at least one of the two opposite sides of the rotor along the central axis of the output shaft, the stator assembly comprises one or more stators, and the plurality of stators are stacked along the central axis, and the stator adopts the above-mentioned stator.

[0015] Optionally, the rotor includes a rotor substrate and permanent magnets, a plurality of the permanent magnets are arranged at intervals along the circumferential direction on the side wall surface of the rotor substrate facing the stator, the magnetization directions of the permanent magnets are parallel to the central axis, the magnetization directions of two adjacent permanent magnets along the circumferential direction are opposite, and the projection of the permanent magnet along the central axis at least partially covers the magnetic flux area and the sensor coil integrated on the stator substrate.

[0016] Optionally, the number of pole pairs of the plurality of permanent magnets is the same as the number of periods of the energized coil.

[0017] Through the above technical scheme, the stator provided by the present invention includes a stator substrate and a driving coil arranged on the stator substrate, so as to drive the rotor to drive the output shaft to rotate. The stator is highly integrated in structure, so as to make the axial size of the motor smaller and the performance more reliable. Specifically, the two energized coils are periodically bent and extended along the circumferential direction and are arranged in an interlaced manner without intersecting each other to form a plurality of magnetic flux areas arranged along the circumferential direction, and then an electrical signal with a phase difference is introduced into the two energized coils to drive the rotor to rotate. At the same time, the energized coils are integrated on the stator substrate, and the air gap is reduced while the axial size is reduced, the output characteristics are improved, and the motor using the stator is more applicable, for example, it can be used in an axially flat space, such as a drone.

[0018] Other features and advantages of the present disclosure will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present disclosure but do not constitute a limitation of the present disclosure. In the accompanying drawings:

[0020] Figure 1 is a schematic diagram of the overall structure of an electromagnetic structure provided in an exemplary embodiment of the present disclosure;

[0021] Figure 2 is a schematic structural diagram of a powered coil connected to a stator substrate provided in an exemplary embodiment of the present disclosure;

[0022] Figure 3 is a schematic structural diagram of a sensor coil connected to a stator substrate provided in an exemplary embodiment of the present disclosure;

[0023] Figure 4 yes Figure 3 A partial enlarged schematic diagram of position A in the middle;

[0024] Figure 5 is a schematic structural diagram of a heat dissipation structure provided in an exemplary embodiment of the present disclosure connected to a stator substrate;

[0025] Figure 6 yes Figure 5 A partial enlarged schematic diagram of position B in the middle;

[0026] Figure 7 is a schematic diagram of a bending and extension of one of the energized coils provided in an exemplary embodiment of the present disclosure;

[0027] Figure 8 Schematic diagram of the positional relationship between the energized coil and the permanent magnet provided in an exemplary embodiment of the present disclosure.

[0028] Description of Reference Numerals

[0029] 1. stator substrate; 11. first side; 12. second side; 2. drive coil; 21. energized coil; 211. first part; 212. second part; 22. magnetic flux area; 3. first connecting part; 4. sensor coil; 41. first unit; 42. second unit; 43. starting end; 44. ending end; 5. rotor substrate; 6. permanent magnet. DETAILED DESCRIPTION

[0030] The specific implementation of the present disclosure is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described herein is only used to illustrate and explain the present disclosure, and is not used to limit the present disclosure.

[0031] In the present disclosure, unless otherwise stated, "inside" and "outside" refer to the inside and outside of the outline of the corresponding component; "far" and "near" refer to the distance and nearness of the corresponding component in space relative to another component. In addition, the terms "first", "second", etc. used in the present disclosure are to distinguish one element from another element and do not have order and importance. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements.

[0032] The stator and the electromagnetic structure in the exemplary embodiments of the present disclosure will be described below with reference to the accompanying drawings.

[0033] According to the first aspect of the present disclosure, referring to Figures 1 to 8 The present disclosure provides a stator, which is arranged with a rotor along the central axis of an output shaft to drive the rotor to drive the output shaft to rotate. The stator includes a stator substrate 1 and a driving coil 2 arranged on the stator substrate 1. The driving coil 2 includes two energized coils 21. The two energized coils 21 are respectively bent and extended periodically along the circumferential direction of the central axis. At the same time, the two energized coils 21 are staggered and non-intersecting along the circumferential direction of the central axis to form a plurality of magnetic flux regions 22 arranged along the circumferential direction.

[0034] Through the above technical solution, the driving coil 2 of the stator provided by the present invention is used to drive the rotor to drive the output shaft to rotate. The stator is highly integrated in structure so as to make the axial size of the motor smaller and the performance more reliable. The stator drives the rotor to rotate based on the principle of electromagnetic induction. When current flows through the driving coil 2, a magnetic field is generated around the driving coil 2. This magnetic field interacts with the rotor to generate torque, thereby driving the rotor to rotate. Specifically, in the present disclosure, two energized coils 21 are periodically bent and extended along the circumferential direction and are arranged in an interlaced manner without intersecting each other to form a plurality of magnetic flux regions 22 arranged along the circumferential direction, and then an electrical signal with a phase difference is introduced into the two energized coils 21 to drive the rotor to rotate. At the same time, the energized coils 21 are integrated on the stator substrate 1. While reducing the axial size, the gap between the stator and the rotor, i.e., the air gap, is reduced accordingly, thereby improving the output power and output efficiency, and the motor using the stator is more applicable, for example, it can be used in an axially flat space, for example, it can be used on a drone, wherein the above-mentioned "electrical signal" can be, for example, a sinusoidal wave or square wave signal with a phase difference of ninety degrees.

[0035] For example, in one application scenario, the motor using the stator can be applied to a drone. For example, the motor can be set on the arm of the drone to drive the blades of the drone to rotate, thereby driving the flight, so as to reduce the overall volume of the drone and facilitate the lightweight design of the drone. In another application scenario, the motor using the stator can also be used on various types of robots, which can reduce the space occupied by the robot. The motor using the stator can be applied to any suitable mechanism according to needs, and the present disclosure does not specifically limit this.

[0036] In some embodiments, Figure 2 and Figure 5 As shown, the stator substrate 1 has a first side surface 11 and a second side surface 12 opposite to each other along the central axis, and the power-carrying coil 21 includes a plurality of first portions 211 exposed on the first side surface 11 and a plurality of second portions 212 exposed on the second side surface 12, and the plurality of first portions 211 and the plurality of second portions 212 are alternately connected in sequence between the input end and the output end of the power-carrying coil 21 along the circumferential direction. Specifically, as Figure 7 As shown, an electrical signal is input from the input end of one of the energized coils 21, and then passes through a plurality of first portions 211 and second portions 212 alternately in sequence before being output from the output end. The first portion 211 may be constructed in any suitable manner. For example, the first portions 211 of the two energized coils 21 may both be constructed as n-type, wherein two adjacent n-type first portions 211 of different energized coils 21 are arranged alternately. When an electrical signal is passed through the two energized coils 21, the projections of the two energized coils 21 along the central axis may have a plurality of magnetic flux regions 22 arranged circumferentially. In addition, the first portion 211 may also be constructed as an arc shape, etc., which is not limited in the present disclosure.

[0037] In some embodiments, Figure 2 and Figure 5 As shown, the first part 211 and the second part 212 can be connected by the first connecting part 3 passing through the first through hole on the stator substrate 1. Therefore, the energized coil 21 can be connected to the stator substrate 1 by way of through hole connection, so that the first part 211 of the energized coil 21 arranged on the first side surface 11 of the stator substrate 1 and the second part 212 arranged on the second side surface 12 of the stator substrate 1 can be connected by the first connecting part 3 under the premise of relying on the through hole process, thereby realizing the conduction of the energized coil 21, and at the same time, the energized coil 21 is connected to the stator matrix in a single layer, further reducing the axial size. It can be understood that the first connecting part 3 can be a part of the first part 211 or the second part 212 of the energized coil 21, or the first connecting part 3 can also be a conductor made of a conductive material such as copper, so as to be filled into the first through hole and connect the first part 211 and the second part 212. In addition, the via connection does not require the use of too many other connecting elements, which can simplify the assembly process of connecting the power coil 21 to the stator substrate 1. At the same time, the via connection of the power coil 21 can better guide the magnetic field and enhance the performance of the motor.

[0038] In some embodiments, Figure 2 and Figure 5 As shown, the first side surface 11 of the stator substrate 1 faces the rotor, and the second part 212 is constructed as or connected with a heat dissipation structure. In this way, the heat dissipation structure can be directly integrated and connected to the stator substrate 1, thereby simplifying the assembly process, and at the same time, the axial size of the stator can be reduced to a certain extent. In addition, the heat dissipation structure can directly act on the energized coil 21, and the heat dissipation effect is good. For example, the second part 212 can be constructed as a heat dissipation structure. Because the energized coil 21 needs to be connected with an electrical signal, the electrical signal is conducted in the first part 211 and the second part 212. Therefore, the heat dissipation structure formed by the second part 212 needs to have good electrical conductivity on the basis of having good thermal conductivity. At this time, the heat dissipation structure can be selected from materials with excellent electrical conductivity and thermal conductivity, such as aluminum alloy heat dissipation plates, copper heat dissipation plates, etc. Alternatively, the second part 212 can also be connected with a heat dissipation structure. Then, the second part 212 can be selected from materials such as aluminum alloy heat dissipation plates, copper heat dissipation plates, etc., or plastic heat dissipation plates or composite materials, etc. At this time, the heat dissipation structure does not affect the conduction of the second part 212 to the electrical signal.

[0039] One embodiment, such as Figure 5As shown, the second part 212 can be constructed as a plate-shaped heat dissipation structure, and the first part 211 is connected to the heat dissipation structure through the first connecting part 3. At this time, the heat dissipation structure needs to use aluminum alloy heat dissipation plates or copper heat dissipation plates and other materials with excellent electrical conductivity and thermal conductivity. At the same time, the heat dissipation structure is constructed in a plate shape, which can increase the heat dissipation area and improve the heat dissipation efficiency.

[0040] In some embodiments, reference Figures 2 to 6 The stator also includes a sensing coil 4, which is arranged on the stator substrate 1 around the central axis. The sensing coil 4 is located on the inner side or the outer side of the driving coil 2 in the radial direction. The sensing coil 4 is used to indirectly detect the rotation speed of the output shaft by detecting the voltage. In this way, the sensing coil 4 is integrated and connected to the stator substrate 1, which can reduce the axial size of the stator. At the same time, no other support parts are required for assembly and the sensing coil 4 does not need to be positioned again, thereby improving the reliability of the stator. Among them, the principle of the sensing coil 4 detecting the rotation speed of the output shaft is to use the change of the magnetic field to sense the change of the rotation speed. When the rotor rotates, the magnetic field will change with the position of the rotor. The change is specifically manifested as the change of magnetic flux. The sensing coil 4 can sense the change of these magnetic fluxes and generate corresponding induced electromotive force, and then determine the rotation speed of the rotor, that is, the rotation speed of the output shaft by measuring the size of the induced electromotive force. In addition, a magnetic induction element such as a magnetoresistive sensor or a Hall sensor can be used to detect the change of the magnetic field, such as the size and direction, and convert it into an electrical signal output, and the rotor speed is calculated by measuring the size and frequency of the electrical signal. The present disclosure is not limited to this.

[0041] In some embodiments, reference Figures 2 to 6 The stator substrate 1 has a first side surface 11 and a second side surface 12 opposite to each other along the central axis. The sensing coil 4 has a plurality of first units 41 located on the first side surface 11 and arranged circumferentially, and a plurality of second units 42 located on the second side surface 12 and arranged circumferentially. The first units 41 and the second units 42 are both arranged in a spiral shape, wherein the number of the first units 41 and the second units 42 is the same, and the number of the first units 41 is the sum of the number of the first parts 211 of the two energized coils 21. Therefore, the sensitivity of the sensing coil 4 is high, that is, the output gain is large, and thus the output voltage is high when detecting the induced electromotive force. Therefore, there is no need for an external amplification circuit to amplify the electrical signal, thereby facilitating the measurement of the rotation speed.

[0042] In some embodiments, reference Figures 2 to 6The sensing coil 4 is connected to the stator substrate 1 by a via connection, and is constructed so that the current flowing through the first unit 41 has the same rotation direction as the current flowing through the second unit 42 located opposite to the first unit 41 on the central axis, and the rotation directions of the currents flowing through the two adjacent first units 41 are opposite, and the rotation directions of the currents flowing through the two adjacent second units 42 are opposite, so that the induced current can flow through the sensing coil 4, wherein the rotation directions of the currents flowing through the two adjacent first units 41 are opposite, and the rotation directions of the currents flowing through the two adjacent second units 42 are opposite, which is exemplarily illustrated as, with reference to Figure 4 and Figure 6 , the rotation direction of the induced current in one of the first units 41 of the sensing coil 4 is clockwise in the drawing, then the rotation direction of the induced current in the first unit 41 adjacent to the first unit 41 is counterclockwise in the drawing, and the rotation direction is opposite; similarly, the rotation direction of the induced current in one of the second units 42 of the sensing coil 4 is clockwise in the drawing, then the rotation direction of the induced current in the second unit 42 adjacent to the second unit 42 is counterclockwise in the drawing, and the rotation direction is opposite. In addition, the current flowing through the first unit 41 and the current flowing through the second unit 42 opposite to the first unit 41 on the central axis have the same rotation direction, which is exemplarily illustrated as, with reference to Figure 4 and Figure 6 The induced current in one of the first units 41 of the sensing coil 4 and the second unit 42 located opposite to the first unit 41 on the central axis are both counterclockwise or clockwise with the same rotation direction when viewed from the same viewing angle perpendicular to the drawing.

[0043] In addition, the sensor coil 4 is connected to the stator substrate 1 by via connection. It can be understood as follows: the wire or printed circuit forming the sensor coil 4 starts from the starting end 43 of the sensor coil 4 (such as Figure 5 As shown in FIG. 1 , a second unit 42 can be first formed on the second side surface 12, and then two first units 41 can be formed on the first side surface 11 after passing through the via holes at the corresponding positions on the stator substrate 1, and then two second units 42 can be formed on the second side surface 12 after passing through the adjacent via holes again, and the two second units 42 can be formed in sequence, and so on, and finally to the terminal end 44 (as shown in FIG. Figure 5 This process is only exemplary. For example, the wire or printed circuit of the sensor coil 4 is formed starting from the starting end 43 of the sensor coil 4. The first unit 41 may also be formed on the first side 11 first. The present disclosure is not limited thereto.

[0044] According to a second aspect of the present disclosure, an electromagnetic structure is provided, including a rotor and a stator assembly, wherein the stator assembly is arranged on at least one of the two opposite sides of the rotor along the central axis of the output shaft, and the stator assembly includes one or more of the above-mentioned stators, and the multiple stators are stacked along the central axis, thereby improving the output characteristics of the rotor, with a larger output power and a faster rotation speed. The multiple stators can be stacked on the same side of the rotor, or respectively arranged on both sides of the rotor. In addition, the combination of the rotor and the stator can also be that the rotor is arranged on both sides of the stator assembly, or the stator assembly and the rotor are arranged interlaced with each other, which is not limited by the present disclosure.

[0045] In some embodiments, Figure 8 As shown, the rotor includes a rotor substrate 5 and a permanent magnet 6. A plurality of permanent magnets 6 are arranged at intervals along the circumferential direction on the side wall surface of the rotor substrate 5 facing the stator. The magnetization direction of the permanent magnet 6 is parallel to the central axis. The magnetization directions of two permanent magnets 6 adjacent to each other along the circumferential direction are opposite. The projection of the permanent magnet 6 along the central axis at least partially covers the magnetic flux area 22 and the sensor coil 4 integrated on the stator substrate 1. In this way, when the electrical signal passes through the energized coil 21, a magnetic field is generated around the coil. The magnetic field interacts with the permanent magnet 6 to generate a torque, thereby driving the rotor to rotate. The magnetization direction of the permanent magnet 6 is parallel to the central axis, which means that one end of the permanent magnet 6 along the central axis is an N pole or an S pole, and the other end is an S pole or an N pole accordingly. In addition, the magnetization directions of two adjacent permanent magnets 6 are opposite, which means, for example, the first end of one of the permanent magnets 6 along the central axis is an N pole, and the second end opposite to the first end is an S pole. Then, the first end of the adjacent permanent magnet 6 along the central axis is an S pole, and the second end is an N pole. It can be understood that the projection of the permanent magnet 6 along the central axis at least partially covers the magnetic flux area 22 so as to be able to sense the change of the magnetic flux. At the same time, the projection of the permanent magnet 6 along the central axis at least partially covers the sensing coil 4 so as to enable the sensing coil 4 to sense the change of the magnetic flux and generate a corresponding induced electromotive force.

[0046] In some embodiments, Figure 8 As shown, the number of pole pairs of the plurality of permanent magnets 6 is the same as the number of periods of the energized coil 21. In this way, the rotating magnetic field of the permanent magnet 6 is synchronized with the current change of the energized coil 21, and the operation is stable and not prone to mutations and vibrations. In addition, there is no additional electromagnetic loss, the efficiency is higher, and the electromagnetic noise is also smaller. Among them, the number of pole pairs of the plurality of permanent magnets 6 can be understood as that, among the plurality of permanent magnets 6, two permanent magnets 6 with opposite magnetization directions are a pair, for example, Figure 8 28 permanent magnets are shown by way of example, and the number of pole pairs is 14. Of course, the number of permanent magnets 6 shown in the figure is only exemplary, and the required number can be arranged according to actual application requirements.

[0047] According to the third aspect of the present disclosure, a motor is provided, comprising the stator described in the first aspect of the present disclosure or the electromagnetic structure described in the second aspect of the present disclosure, so that the motor has a smaller axial dimension and can be installed in a flat space, while having higher output characteristics and a smoother operation process.

[0048] According to a fourth aspect of the present disclosure, a drone is provided, comprising the motor according to the third aspect of the present disclosure, wherein the motor can be arranged on the arm of the drone to drive the blades of the drone to rotate. In this way, the size of the drone is correspondingly reduced to be able to adapt to a small working environment, and the flight process is stable and the flight power is strong.

[0049] The present disclosure exemplarily illustrates the installation and use process of the electromagnetic structure.

[0050] First, the two energized coils 21 are periodically bent and extended through vias and arranged on the stator substrate in an interlaced manner without intersecting each other. At this time, the first part 211 and the second part 212 of the energized coil 21 are connected through the vias of the first connecting part 3, and the second part 212 is constructed as a plate-shaped heat dissipation structure. Then, the sensor coil 4 is integrated and arranged on the stator substrate 1 through vias around the central axis, and the sensor coil 4 is located radially inside the driving coil 2. During use, an electrical signal with a phase difference can be introduced into the two energized coils 21. When the electrical signal passes through the energized coil 21, a magnetic field is generated around the coil, and the magnetic field interacts with the permanent magnet 6 to generate a torque to drive the rotor to rotate.

[0051] The preferred embodiments of the present disclosure are described in detail above in conjunction with the accompanying drawings; however, the present disclosure is not limited to the specific details in the above embodiments. Within the technical concept of the present disclosure, a variety of simple modifications can be made to the technical solution of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

[0052] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0053] In addition, various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.

Claims

1. A stator, characterized in that: The stator is used to be arranged with the rotor along the central axis of the output shaft to drive the rotor to drive the output shaft to rotate, and the stator includes: a stator base plate; and The driving coil is arranged on the stator substrate, and the driving coil includes two energized coils. The two energized coils are each periodically bent and extended along the circumferential direction of the central axis. The two energized coils are staggered and non-intersecting along the circumferential direction of the central axis to form a plurality of magnetic flux areas arranged along the circumferential direction.

2. The stator according to claim 1, characterized in that: The stator substrate has a first side surface and a second side surface opposite to each other along the central axis, and the energized coil includes a plurality of first portions exposed on the first side surface and a plurality of second portions exposed on the second side surface, and the plurality of first portions and the plurality of second portions are alternately connected in sequence along the circumferential direction between the input end and the output end of the energized coil.

3. The stator according to claim 2, characterized in that: The first portion and the second portion are connected via a first connecting portion passing through a first via hole on the stator substrate.

4. The stator according to claim 2, characterized in that: The first side surface of the stator substrate faces the rotor, and the second portion is configured as or connected to a heat dissipation structure.

5. The stator according to claim 2, characterized in that: The second part is constructed as a plate-shaped heat dissipation structure.

6. The stator according to any one of claims 1 to 5, characterized in that: The stator further comprises a sensing coil, which is arranged on the stator substrate around the central axis and radially located inside or outside the driving coil. The sensing coil is used to indirectly detect the rotation speed of the output shaft by detecting an induced voltage.

7. The stator according to claim 6, characterized in that The sensing coil comprises a plurality of first units located on a first side surface of the stator substrate and arranged along the circumferential direction, and a plurality of second units located on a second side surface of the stator substrate and arranged along the circumferential direction, the first units and the second units are both arranged in a spiral shape, the sensing coil is connected to the stator substrate by via connection, and is constructed so that the rotation direction of the current flowing through the first unit is the same as the rotation direction of the current flowing through the second unit located opposite to the first unit on the central axis, and the rotation directions of the current flowing through two adjacent first units are opposite, and the rotation directions of the current flowing through two adjacent second units are opposite.

8. An electromagnetic structure, characterized in that: It comprises a rotor and a stator assembly, wherein the stator assembly is arranged on at least one of the two opposite sides of the rotor along the central axis of the output shaft, the stator assembly comprises one or more stators, and the plurality of stators are stacked along the central axis, and the stator is the stator described in any one of claims 1 to 7.

9. The electromagnetic structure according to claim 8, characterized in that: The rotor includes a rotor substrate and permanent magnets. A plurality of permanent magnets are arranged at intervals along the circumferential direction on the side wall surface of the rotor substrate facing the stator. The magnetization directions of the permanent magnets are parallel to the central axis. The magnetization directions of two adjacent permanent magnets along the circumferential direction are opposite. The projection of the permanent magnet along the central axis at least partially covers the magnetic flux area and the sensor coil integrated on the stator substrate.

10. The electromagnetic structure according to claim 9, characterized in that: The number of pole pairs of the plurality of permanent magnets is the same as the number of periods of the energized coil.

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