Stator structure and alternating current motor

Abstract

A stator structure (1) and an alternating current motor. The stator structure comprises a stator yoke (10) and a flexible printed circuit (20); a through cavity (11) open at both ends is formed inside the stator yoke; the flexible printed circuit is wound and attached to the wall of the cavity, one end of the flexible printed circuit is provided with a wiring terminal (28) configured to be connected to an external alternating current power supply, the flexible printed circuit comprises at least two conductive layers (21, 22), each conductive layer is internally provided with a plurality of wires (23), each wire in one conductive layer (21) and the corresponding wire in the other conductive layer (22) are electrically connected and enclose to form a coil (24), and there are a plurality of coils, which are arranged at intervals along the circumferential direction of the stator yoke and are all electrically connected to the wiring terminal; and the flexible printed circuit is attached to the inner wall of the stator yoke, current flows through the coils and generates a radial magnetic field perpendicular to the stator yoke, and the magnetic field forms a magnetic circuit by using the stator yoke.

Description

Stator structure and AC motor

[0001] This application claims priority to Chinese Patent Application No. 2025103704230, filed on March 27, 2025, entitled "Stator Structure and AC Motor", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This invention relates to the field of motor technology, and in particular to a stator structure and an AC motor. Background Technology

[0003] High-performance motors are used in applications such as robotics and medical equipment where motor size and performance requirements are high. For example, three-phase AC motors, especially permanent magnet AC motors, have become an important technological path for high performance and miniaturization due to their high torque density, high efficiency, and good reliability. These motors utilize the alternating current in the stator windings to generate a rotating magnetic field, which interacts with the magnetic field generated by the permanent magnet material on the rotor, thereby producing electromagnetic torque.

[0004] However, for three-phase permanent magnet AC motors, the stator structure includes a stator core and stator armature windings. While this design enables efficient electromagnetic conversion, the overall structure is relatively complex. In small motor applications, the machining and assembly of this complex stator structure are difficult, making large-scale mass production challenging. Summary of the Invention

[0005] The main objective of this invention is to propose a stator structure and an AC motor that aims to solve the problem of the difficulty in processing and assembling existing stator structures.

[0006] To achieve the above objectives, the stator structure proposed in this invention includes a stator yoke and a flexible circuit board; the stator yoke has a cavity with two through ends; the flexible circuit board is wound and fits against the cavity wall, one end of the flexible circuit board is provided with a terminal for connecting an external AC power source, the flexible circuit board includes at least two conductive layers, each conductive layer has multiple wires, the wires in one conductive layer are electrically connected to the wires in another conductive layer and surround to form a coil, there are multiple coils, the multiple coils are arranged at intervals along the circumference of the stator yoke and connected in series to form a phase winding, and all are electrically connected to the terminal;

[0007] The flexible circuit board is attached to the inner wall of the stator yoke. Current flows through the coil and generates a radial magnetic field perpendicular to the stator yoke in the motor air gap. This magnetic field forms a magnetic field loop using the stator yoke.

[0008] In one embodiment of the present invention, multiple sets of the coils are connected in series to form a full-pitch distributed lap winding group;

[0009] The flexible circuit board includes a first conductive layer and a second conductive layer. Multiple conductive vias are formed on the edges of both the first and second conductive layers. A conductor in the first conductive layer is electrically connected to a conductor in the second conductive layer through a conductive via located on the edge of the flexible circuit board. A conductor in the second conductive layer is electrically connected to another conductor in the first conductive layer through a conductive via located on the other edge of the flexible circuit board. Another conductor in the first conductive layer is electrically connected to another conductor in the second conductive layer through a conductive via located on the edge of the flexible circuit board, thus ultimately forming a complete full-pitch distributed lap winding.

[0010] The plurality of wires in the first conductive layer are sequentially and alternately connected to the plurality of wires in the second conductive layer to form a phase full-pitch distributed lap winding.

[0011] In one embodiment of the present invention, the conductor includes at least a first segment, a second segment, and a third segment connected in sequence. The second segment is parallel to the axial direction of the stator yoke. The first segment and the third segment are both inclined relative to the second segment in the same direction. The multiple conductors in each conductive layer are arranged at intervals along the circumference of the stator yoke.

[0012] In one embodiment of the present invention, at least one first segment in the first conductive layer and at least one first segment in the second conductive layer are arranged intersecting along a projection perpendicular to the surface of the flexible circuit board; at least one third segment in the first conductive layer and at least one third segment in the second conductive layer are arranged intersecting along a projection perpendicular to the surface of the flexible circuit board.

[0013] In one embodiment of the present invention, a plurality of second segments in the first conductive layer and a plurality of second segments in the second conductive layer are evenly arranged at projection intervals perpendicular to the surface of the flexible circuit board, and the two ends of the flexible circuit board abut against and are wound and attached to the inner wall of the stator yoke.

[0014] In one embodiment of the present invention, a plurality of second segments in the first conductive layer coincide with a plurality of second segments in the second conductive layer along a projection portion perpendicular to the surface of the flexible circuit board, or the spacing between some of the lines is small, and the two ends of the flexible circuit board partially overlap and are wound and attached to the inner wall of the stator yoke.

[0015] In one embodiment of the present invention, the line width of the second segment is greater than the line width of the first segment and the third segment.

[0016] In one embodiment of the present invention, the flexible circuit board is polygonal in shape, and the wires are parallel to the sides of adjacent flexible circuit boards.

[0017] Alternatively, the flexible circuit board may be rectangular in shape, and the conductors may be at right angles near the corners of the flexible circuit board.

[0018] In one embodiment of the present invention, the conductive layer has a midpoint connection hole, and multiple wires in the conductive layer are wound to form a three-phase full-pitch distributed lap winding. All three phases of the full-pitch distributed lap winding are electrically connected to the midpoint connection hole, and the connection method of the three phases of the full-pitch distributed lap winding is Y-shaped.

[0019] The present invention also proposes an AC motor, the AC motor comprising a rotor and a stator structure as described above; the rotor is rotatably disposed within the cavity, and the flexible circuit board surrounds the outer periphery of the rotor.

[0020] The stator structure proposed in this invention includes a stator yoke and a flexible circuit board. A cylindrical cavity is formed inside the stator yoke. The flexible circuit board includes at least two conductive layers. The flexible circuit board is wound into a cylindrical or tubular shape and attached to the inner wall of the stator yoke. The flexible circuit board includes at least two conductive layers, and each conductive layer contains multiple wires. The wires in one conductive layer are electrically connected to the wires in another conductive layer and form a coil. There are multiple coils, which are arranged at intervals along the circumference of the stator yoke. At the same time, one end of the flexible circuit board is provided with a terminal, through which the coils are electrically connected to an external AC power source. Because the multiple sets of coils on the wound flexible circuit board are arranged at intervals along the circumference of the stator yoke, the changing current generates a magnetic field. Therefore, the multiple sets of coils generate a radial magnetic field in the air gap of the motor to drive the rotor to rotate.

[0021] This application employs a method of placing coils on a flexible circuit board and attaching them to the inner wall of the stator yoke. Compared to placing the coils in the stator slots of the stator core, this application reduces the structural volume occupied by the stator structure. Furthermore, it eliminates the need for stator slots on the stator yoke; the stator structure can be installed simply by attaching, improving the ease of processing and assembly of the motor's stator structure. Simultaneously, the coil is formed by connecting and enclosing wires within two conductive layers. That is, each winding wire in the coil is placed within one of the two conductive layers. Compared to placing multiple wires in the coil within the same conductive layer, this application also reduces the difficulty of coil manufacturing, eliminating the need for complex winding equipment and manufacturing processes, and improving the manufacturing precision of the stator structure. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0023] Figure 1 is a structural schematic diagram of an embodiment of the AC motor provided by the present invention;

[0024] Figure 2 is a cross-sectional view of Figure 1 along point AA;

[0025] Figure 3 is a structural schematic diagram of another embodiment of the AC motor provided by the present invention;

[0026] Figure 4 is a schematic diagram of a structural embodiment of the flexible circuit board in the stator structure provided by the present invention;

[0027] Figure 5 is a schematic diagram of the unfolded flexible circuit board in Figure 4;

[0028] Figure 6 is a schematic diagram of the unfolded structure of the two conductive layers in the flexible circuit board in Figure 5.

[0029] Figure 7 is a schematic diagram of the structure of the first winding in the flexible circuit board in Figure 5;

[0030] Figure 8 is a schematic diagram of the structure of the second winding in the flexible circuit board in Figure 5;

[0031] Figure 9 is a schematic diagram of the third winding in the flexible circuit board in Figure 5;

[0032] Figure 10 is a schematic diagram of another embodiment of the flexible circuit board in the stator structure provided by the present invention;

[0033] Figure 11 is a schematic diagram of the unfolded flexible circuit board in Figure 10;

[0034] Figure 12 is a schematic diagram of the unfolded structure of the two conductive layers in the flexible circuit board of Figure 11;

[0035] Figure 13 is a schematic diagram of the structure of the first winding in the flexible circuit board of Figure 11;

[0036] Figure 14 is a schematic diagram of the structure of the second winding in the flexible circuit board of Figure 11;

[0037] Figure 15 is a schematic diagram of the third winding in the flexible circuit board of Figure 11;

[0038] Figure 16 is a partially enlarged schematic diagram of one of the windings in the flexible circuit board of Figure 11;

[0039] Figure 17 is a schematic diagram of the unfolded structure of another embodiment of the flexible circuit board in the stator structure of the present invention;

[0040] Figure 18 is a schematic diagram of the unfolded structure of another embodiment of the flexible circuit board in the stator structure of the present invention.

[0041] Explanation of reference numerals: 1. Stator structure; 10. Stator yoke; 11. Cavity; 20. Flexible circuit board; 21. First conductive layer; 22. Second conductive layer; 23. Conductor; 231. First segment; 232. Second segment; 233. Third segment; 24. Coil; 25. Conductive through-hole; 26. Full-pitch distributed lap winding; 27. Midpoint connection hole; 28. Terminal; 281. Power supply pad; 30. Rotor; 40. Magnetic field detection component; 41. Circuit control board; 42. Hall sensor.

[0042] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0043] The technical solutions of the embodiments of the present invention will now be described with reference to the accompanying drawings. Obviously, the described embodiments are merely a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0044] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0045] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are 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. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0046] This invention proposes a stator structure 1.

[0047] Referring to Figures 1 to 5, in one embodiment of the present invention, the stator structure 1 includes a stator yoke 10 and a flexible circuit board 20; the stator yoke 10 has a cavity 11 with both ends through it; the flexible circuit board 20 is wound and fits against the cavity wall of the cavity 11; one end of the flexible circuit board 20 is provided with a terminal 28 for connecting to an external AC power source; the flexible circuit board 20 includes at least two conductive layers; each conductive layer has multiple wires 23; the wires 23 in one conductive layer are electrically connected to the wires 23 in another conductive layer and surround to form a coil 24; there are multiple coils 24; the multiple coils 24 are arranged at intervals along the circumference of the stator yoke 10 and are all electrically connected to the terminal 28.

[0048] The flexible circuit board 20 is attached to the inner wall of the stator yoke 10. Current passes through the coil 24 and generates a radial magnetic field perpendicular to the stator yoke 10 in the motor air gap. This magnetic field forms a magnetic field loop using the stator yoke 10.

[0049] In this embodiment, the stator structure 1 includes a cylindrical stator yoke 10, with a cavity 11 extending through both ends. The stator yoke 10 is made of a soft magnetic material with high permeability, a choice that significantly improves the magnetic field strength and efficiency of the motor. The stator yoke 10 can be manufactured using various processes, such as bonding, welding, or a combination of bonding and welding, to fix multiple pieces of soft magnetic material together to form a robust integral structure. Furthermore, the shape of the stator yoke 10 can be designed into different geometric shapes, such as cylindrical or polygonal prisms, to adapt to different motor application scenarios.

[0050] The flexible circuit board 20 is one of the core components of this invention, and it is manufactured using FPCB (Flexible Printed Circuit Board) technology. The flexible circuit board 20 comprises at least two conductive layers, each containing multiple conductive wires 23. These conductive wires 23 are manufactured using precision lamination, photolithography, and etching processes, resulting in high precision and consistency. To prevent short circuits between the two conductive layers, each conductive layer contains two insulating layers, with the multiple conductive wires 23 sandwiched between the two insulating layers. These insulating layers are made of a high-temperature resistant material with excellent insulation properties, such as polyimide.

[0051] One end of the flexible circuit board 20 is provided with a terminal 28 for connecting to an external AC power source. The design of the terminal 28 needs to consider the stability and reliability of current transmission, so a metal material with good conductivity, such as copper, is usually selected. The terminal 28 can be connected to the external power source by means of soldering, crimping, etc., to ensure that the current can be efficiently transmitted to the various coils 24 on the flexible circuit board 20.

[0052] The coil 24 is formed by alternating connections of wires 23 within two conductive layers. This design not only simplifies the manufacturing process of the coil 24 but also improves its precision and stability. Compared to a scheme where multiple wires 23 in the coil 24 are all placed in the same conductive layer, the coil 24 in this application is formed by connecting and enclosing wires 23 within two conductive layers through conductive through-holes 25 located at the edge of the flexible circuit board 20. That is, each winding wire 23 in the coil 24 is respectively placed within two conductive layers. This method reduces the difficulty of manufacturing the coil 24, eliminating the need for complex winding equipment and manufacturing processes, thereby improving the manufacturing precision of the stator structure 1. The number and layout of the coils 24 can be adjusted according to the specific requirements of the motor. Multiple coils 24 are evenly spaced along the circumference of the stator yoke 10 to ensure a uniform magnetic field distribution. Furthermore, the rotation direction of the coils 24 can be designed according to actual application requirements, and can be either clockwise or counterclockwise to meet different magnetic field direction requirements.

[0053] When current flows through coil 24, a radial magnetic field perpendicular to the stator yoke 10 is generated in the air gap of the motor. This magnetic field forms a closed magnetic field loop using the stator yoke 10, thereby driving the rotor 30 to rotate. To further optimize the distribution of the magnetic field, multiple coils 24 are arranged at uniform intervals along the circumference of the stator yoke 10. This arrangement not only improves the uniformity of the magnetic field but also reduces vibration and noise during motor operation.

[0054] The flexible circuit board 20 can be directly attached to the inner wall of the stator yoke 10, simplifying the installation process. Compared with the traditional method of setting the coil 24 in the stator slot of the stator core, the design of this invention greatly reduces the structural volume occupied by the stator winding and improves the convenience of processing and assembly.

[0055] In some embodiments, the flexible circuit board 20 may also integrate a magnetic field detection component 40, such as a Hall sensor 42 and a circuit control board 41. The Hall sensor 42 is used to detect the magnetic field of the rotor 30 during motor operation, and thus detect the angle of the rotor 30. The circuit control board 41 is used to process the data collected by the Hall sensor 42 and feed it back to the control system to achieve precise motor control. This design not only improves the control accuracy of the motor, but also enhances the reliability and stability of the system.

[0056] This application employs a flexible circuit board 20 to replace the traditional stator core and stator slot structure, greatly simplifying the stator winding installation process and significantly reducing the structural volume occupied by the stator winding. The flexible circuit board 20, manufactured using high-precision FPCB technology, makes the fabrication of the coil 24 simpler and more precise. Furthermore, the multi-layer conductive design of the coil 24 not only improves the uniformity of the magnetic field and the motor's operating efficiency but also reduces resistance loss, enhancing the overall performance of the motor.

[0057] The applicant has made a series of improvements and studies on slotless stator windings. In some embodiments, it is possible to arrange all the conductors 23 of the same coil 24 within the same conductive layer, which can also reduce the structural volume of the stator winding. However, to achieve a more uniform rotating magnetic field, there are requirements for the shape, direction of rotation, and spacing between the conductors of the coil 24. Furthermore, to realize the coil 24 within the same conductive layer, it needs to be connected to other windings inside the winding using connecting holes, making the winding processing difficult and the precision hard to control. At the same time, such concentric coils formed within the same conductive layer have a low ability to generate back EMF, resulting in a low motor constant and thus poor electromagnetic characteristics. The full-pitch distributed coil in this application can improve the coil's ability to generate back EMF, and the efficiency and torque density of the motor can also be improved.

[0058] In this embodiment, the coil 24 is specifically designed to be formed by connecting and enclosing wires 23 within two conductive layers. This reduces the difficulty of manufacturing the coil 24, eliminating the need for complex winding equipment and manufacturing processes, thereby improving the manufacturing precision of the stator structure 1. This design is suitable not only for small motors but also for high-performance motor applications where space utilization is critical.

[0059] As shown in Figures 4 to 8, in one embodiment of the present invention, multiple sets of coils 24 are connected in series to form a full-pitch distributed lap winding 26;

[0060] The flexible circuit board 20 includes a first conductive layer 21 and a second conductive layer 22. Multiple conductive vias 25 are provided on the edges of both the first conductive layer 21 and the second conductive layer 22. A wire 23 in the first conductive layer 21 is electrically connected to a wire 23 in the second conductive layer 22 through a conductive via 25 located on the edge of the flexible circuit board 20. A wire 23 in the second conductive layer 22 is electrically connected to another wire 23 in the first conductive layer 21 through a conductive via 25 located on the other edge of the flexible circuit board 20. Another wire 23 in the first conductive layer 21 is electrically connected to another wire 23 in the second conductive layer 22 through a conductive via 25 located on the edge of the flexible circuit board 20.

[0061] Multiple conductors 23 in the first conductive layer 21 are alternately connected to multiple conductors 23 in the second conductive layer 22 to form a phase-spaced distributed lap winding 26.

[0062] In this embodiment, the full-pitch distributed lap winding 26 can generate a back electromotive force close to a sine wave, which makes the electromagnetic performance of the motor more stable during operation, reduces the influence of higher harmonics, and thus reduces motor losses and noise. Due to its distributed characteristics, it can effectively weaken harmonic magnetomotive force and improve the starting performance of the motor. In addition, since the wires 23 in its coil 24 are arranged in two overlapping conductive layers and connected in series through conductive through-holes 25 located at the edge of the flexible circuit board 20 to form a winding, compared with a concentrated winding, the formation of this full-pitch distributed lap winding 26 does not require folding the flexible circuit board 20, which facilitates manufacturing and installation.

[0063] Each set of phase-pitch distributed lap windings 26 consists of multiple conductors 23 distributed in the first conductive layer 21 and the second conductive layer 22 of the flexible circuit board 20, and passing through conductive vias 25 located at the edge of the flexible circuit board 20. The multiple conductors 23 in the two conductive layers are separated by an insulating layer to prevent short circuits. The conductors 23 are made of highly conductive materials (such as copper or silver) to ensure efficient current transmission.

[0064] The multiple wires 23 located in the first conductive layer 21 have the same spacing and shape, and the multiple wires 23 located in the second conductive layer 22 also have the same spacing and shape. Therefore, through this connection method, a full-pitch distributed lap winding can be formed. Compared to the scheme of continuously winding coils 24 within the same conductive layer, this embodiment improves the ease of processing the full-pitch distributed lap winding, improves the wiring convenience of each wire 23 in the coil 24, and improves the uniformity of the magnetic field generated by the formed full-pitch distributed lap winding in both the circumferential and axial directions, enabling the generation of back electromotive force with a higher motor constant. These solutions and effects are unattainable by the scheme of forming a set of coils 24 within the same conductive layer.

[0065] To achieve electrical connection between the conductors 23 of the two conductive layers, conductive vias 25 can be provided on the conductive layers. Multiple conductive vias 25 in each conductive layer overlap each other in the thickness direction of the unfolded flexible circuit board 20 (refer to Figures 5 and 6, the direction of the flexible circuit board 20 perpendicular to the paper). Each conductive via 25 is copper-plated to ensure good conductivity. One conductor 23 in the first conductive layer 21 is electrically connected to one conductor 23 in the second conductive layer 22 through the conductive via 25. Then, another conductor 23 in the second conductive layer 22 is electrically connected to another conductor 23 in the first conductive layer 21, and so on, until a complete full-pitch distributed lap winding 26 is formed.

[0066] The rotation direction of coil 24 can be designed according to actual application requirements, and can be either clockwise or counterclockwise to meet different magnetic field direction requirements. In the full-pitch distributed lap winding 26, multiple conductors 23 are connected sequentially between two conductive layers, while multiple sets of coils 24 are arranged as a whole along the circumference of stator yoke 10, and multiple coils 24 are also arranged along the circumference of stator yoke 10 to ensure uniform magnetic field distribution.

[0067] In this embodiment, the coil 24 is formed by alternating connections of wires 23 within two conductive layers through conductive vias 25 located at the edge of the flexible circuit board 20. Compared to concentrating all wires 23 in the same conductive layer, this method reduces the difficulty of manufacturing the coil 24, eliminating the need for complex winding equipment and manufacturing processes, thereby improving the manufacturing precision of the stator structure 1. Simultaneously, the arrangement and winding of the wires 23 in the coil 24 are more uniform, resulting in a more uniform magnetic field distribution.

[0068] Furthermore, the conductor 23 can have different shapes, such as straight, polygonal, or curved, to suit different application scenarios. In some high-power motors, a thicker conductor 23 cross-section can be selected to reduce resistance loss and improve the overall efficiency of the motor.

[0069] As shown in Figures 4 and 8, in one embodiment of the present invention, the conductor 23 includes at least a first segment 231, a second segment 232 and a third segment 233 connected in sequence. The second segment 232 is parallel to the axial direction of the stator yoke 10. The first segment 231 and the third segment 233 are both inclined in different directions relative to the second segment 232. The multiple conductors 23 in each conductive layer are arranged sequentially at intervals along the circumference of the stator yoke 10.

[0070] In this embodiment, the conductor 23 adopts a multi-segment design. The second segment 232 is parallel to the axis of the stator yoke 10, while the first segment 231 and the third segment 233 are relatively inclined, which makes the magnetic field of the full-pitch distributed lap winding 26 formed by the combination of multiple conductors 23 more uniform. Since the conductor 23 of each conductive layer is formed by connecting the first segment 231, the second segment 232 and the third segment 233, and in the same coil 24, the inclination angle of the first segment 231 and the third segment 233 relative to the second segment 232 can be set to be the same to facilitate the winding and manufacturing of the conductor 23.

[0071] As shown in Figures 5 and 6, multiple wires 23 in each conductive layer are arranged at intervals along the circumference of the stator yoke 10. The structure of each wire 23 in each conductive layer is designed to be the same and evenly spaced. The wires in the two conductive layers are arranged symmetrically so that when one wire 23 in one conductive layer is connected to another wire 23 in another conductive layer, a coil 24 structure with a shape similar to a rhombus is formed. Thus, when the coil 24 is energized, the changing current forms a magnetic field along the radial direction of the stator yoke 10.

[0072] The tilt angles of the first segment 231 and the third segment 233 of conductor 23 relative to the second segment 232 can be adjusted according to actual needs to optimize the magnetic field distribution and reduce heat accumulation in areas of concentrated current density. For example, in high-power motors, an appropriate tilt angle can improve heat dissipation performance and reduce vibration and noise during motor operation.

[0073] Understandably, because this application places each wire in the coil separately within the first and second conductive layers, it facilitates the formation of coils of different shapes and sizes by changing the shape and angle of the wires within the first and second conductive layers as needed. Compared to the scheme of forming a coil within the same conductive layer, this design scheme of the present application can significantly improve the back EMF generation capability of the motor coil and enhance the electromagnetic characteristics of the winding. Simultaneously, the winding fabrication of the wires is also relatively easy to achieve.

[0074] Referring to Figures 6 to 8, in one embodiment of the present invention, at least one first segment 231 in the first conductive layer 21 and at least one first segment 231 in the second conductive layer 22 are arranged intersecting along a projection perpendicular to the surface of the flexible circuit board 20; at least one third segment 233 in the first conductive layer 21 and at least one third segment 233 in the second conductive layer 22 are arranged intersecting along a projection perpendicular to the surface of the flexible circuit board 20.

[0075] In this embodiment, since an insulating layer is provided between the wires 23 in the two conductive layers, although the third segment 233 in the first conductive layer 21 and the third segment 233 in the second conductive layer 22 are arranged intersectingly along the projection perpendicular to the surface of the flexible circuit board 20, a short circuit between the wires 23 will not occur. Furthermore, this structural design results in the coil 24, as shown in Figures 6 to 8, extending circumferentially along the stator yoke 10 while rotating clockwise or counterclockwise. Therefore, when the flexible circuit board 20 is wound and attached to the inner wall of the stator yoke 10, the resulting magnetic field is more uniformly distributed circumferentially along the stator yoke 10. In other embodiments, the full-pitch distributed lap winding 26 can also be provided with multiple wires 23 connected and rotated around the same center.

[0076] Referring to Figures 3 to 8, in one embodiment of the present invention, a plurality of second segments 232 in the first conductive layer 21 and a plurality of second segments 232 in the second conductive layer 22 are evenly arranged along a projection interval perpendicular to the surface of the flexible circuit board 20, and the two ends of the flexible circuit board 20 abut against and are wound and attached to the inner wall of the stator yoke 10.

[0077] In this embodiment, the plurality of second segments 232 in the first conductive layer 21 and the plurality of second segments 232 in the second conductive layer 22 are evenly spaced on a projection perpendicular to the surface of the flexible circuit board 20. This uniform arrangement ensures that the current is evenly distributed between the two conductive layers, enhances the uniformity and strength of the magnetic field, and reduces vibration and noise problems. At the same time, this evenly spaced arrangement of the second segments 232 makes the magnetic field evenly distributed in the circumferential direction of the stator yoke 10. Therefore, by abutting and winding the two ends of the flexible circuit board 20 against the inner wall of the stator yoke 10, the second segments 232 in the flexible circuit board 20 are distributed at intervals along the circumferential direction of the stator yoke 10, thereby improving the uniformity of the magnetic field distribution.

[0078] Referring to Figures 9 to 15, in one embodiment of the present invention, a plurality of second segments 232 in the first conductive layer 21 and a plurality of second segments 232 in the second conductive layer 22 overlap along the projection portion perpendicular to the surface of the flexible circuit board 20, or the spacing between some of the lines is small, and the two ends of the flexible circuit board 20 partially overlap and are wound and attached to the inner wall of the stator yoke 10.

[0079] In this embodiment, as shown in Figures 6 and 11, the area occupied by the multiple second segments 232 in the second conductive layer 22 partially overlaps with the area occupied by the multiple second segments 232 in the first conductive layer 21. Within this overlapping area, the projections of the multiple second segments 232 in the first conductive layer 21 onto the surface of the flexible circuit board 20 can coincide with or be spaced apart from the projections of the multiple second segments 232 in the second conductive layer 22. It is understood that within this overlapping area, the spacing between the second segments 232 in the first conductive layer 21 and adjacent second segments 232 in the second conductive layer 22 is smaller, resulting in a higher magnetic field strength. This design increases the current density and enhances the local magnetic field strength.

[0080] Furthermore, the two ends of the flexible circuit board 20 (refer to Figure 11, one end being the left part of the line connecting the centers of the upper and lower conductive holes on the leftmost side of the flexible circuit board 20, and the other end being the right part of the line connecting the centers of the upper and lower conductive holes on the rightmost side of the flexible circuit board 20) are at least partially overlapped and wound and attached to the inner wall of the stator yoke 10. As shown in Figures 6 and 11, in the overlapping portions of the two ends of the flexible circuit board 20, multiple second segments 232 in the first conductive layer 21 and the second conductive layer 22 are at least partially overlapped or at least partially staggered in the radial direction of the wound flexible circuit board 20; or partially overlapped and partially staggered. Therefore, when the flexible circuit board 20 is wound, overlapping the two ends of the flexible circuit board 20 reduces the spacing and / or increases the density of the second segments 232, which were originally relatively large and low in density, due to the overlap after the flexible circuit board 20 is wound. Through the above structural design and winding method, the magnetic field formed by the flexible circuit board 20 is more uniformly distributed in the circumferential direction of the stator yoke 10, and the magnetic field strength is higher. This design is particularly suitable for application scenarios with high requirements for magnetic field strength and motor efficiency, improving the strength and uniformity of the magnetic field and reducing vibration and noise during motor operation.

[0081] In one embodiment of the present invention, the line width of the second segment 232 is greater than the line width of the first segment 231 and the third segment 233.

[0082] In this embodiment, the second segment 232 is parallel to the axial direction of the stator yoke 10, and its linewidth is greater than that of the first segment 231 and the third segment 233. This design reduces resistance loss, improves current transmission efficiency, and reduces the risk of localized heat generation. The wider second segment 232 helps optimize the current path, allowing the current to be distributed more evenly between the two conductive layers, enhancing the uniformity and strength of the magnetic field, and improving the heat dissipation performance of the motor. In addition, as shown in Figures 6 to 8, compared to the first segment 231 and the third segment 233, the spacing between the multiple second segments 232 is larger, and the wider spacing facilitates the fabrication of the wider linewidth second segments 232.

[0083] Referring to Figures 4 to 8 and Figures 10 to 15, in one embodiment of the present invention, the flexible circuit board 20 is polygonal in shape, and the wires 23 are parallel to the sides of adjacent flexible circuit boards 20.

[0084] Alternatively, as shown in Figures 16 and 17, the flexible circuit board 20 is rectangular in shape, and the conductor 23 is at a right angle near the corner of the flexible circuit board 20.

[0085] In this embodiment, the flexible circuit board 20 can be hexagonal, octagonal, etc. When the flexible circuit board 20 is polygonal, the wire 23 is parallel to the side of the adjacent flexible circuit board 20. This design allows the wire 23 to better fit the inner wall of the stator yoke 10 during the winding process and optimizes the magnetic field distribution. The polygonal design provides more flexibility and is suitable for stator yokes 10 of different shapes and sizes, improving the convenience of installation and assembly.

[0086] In another embodiment, when the flexible circuit board 20 is rectangular, the wires 23 are at right angles near the corners, so that the wires 23 located at the edge of the flexible circuit board 20 are more adapted to the shape of the flexible circuit board 20, thereby increasing the number and density of wiring on the surface of the flexible circuit board 20. At the same time, when the flexible circuit board 20 is wound around the inner wall of the stator yoke 10, the magnetic field generated by the flexible circuit board 20 can be more uniform in the circumferential and axial directions of the stator yoke 10, so as to make full use of the space of the rectangular flexible circuit board 20.

[0087] Referring to Figures 4 to 8 and Figures 10 to 17, in one embodiment of the present invention, the conductive layer has a plurality of conductive vias 25, and at least two conductive layers are stacked. The plurality of conductive vias 25 in one conductive layer coincide with the plurality of conductive vias 25 in the remaining conductive layers in a direction perpendicular to the conductive layer. The two wires 23 of each coil 24 are electrically connected through the conductive vias 25. These conductive vias 25 coincide with each other in a direction perpendicular to the conductive layer to achieve electrical connection between different conductive layers.

[0088] In this embodiment, multiple conductive vias 25 are formed on each conductive layer. These vias are precisely aligned to ensure that the wires 23 on different conductive layers can be electrically connected through the vias. The conductive vias 25 are copper-plated to ensure good conductivity and mechanical strength.

[0089] At least two conductive layers are stacked together, and multiple conductive vias 25 in each conductive layer overlap each other in the vertical direction. This design allows current to be smoothly transmitted between different conductive layers, forming a complete current path. The two wires 23 in different layers of the coil 24 are electrically connected through the conductive vias 25.

[0090] In addition, as shown in Figures 4 to 8 and Figures 10 to 17, the terminal 28 is provided with three power supply pads 281, and multiple coils 24 are electrically connected to the three power supply pads 281 respectively, forming three full-pitch distributed lap windings 26. The three full-pitch distributed lap windings 26 are combined to form a three-phase winding with an electrical angle difference of 120 degrees or 240 degrees.

[0091] Terminal 28 has an interface for connecting to an external AC power source and includes three power supply pads 281 (e.g., A, B, C). Each power supply pad 281 is connected to a set of coils 24, forming an independent full-pitch distributed lap winding 26. This design simplifies the connection to the external power source and ensures that each phase of the full-pitch distributed lap winding 26 can be powered independently.

[0092] The flexible circuit board 20 also has power supply vias located between the coil 24 and the power supply pad 281. Each coil 24 in the full-pitch distributed lap winding 26 is electrically connected to the corresponding power supply pad 281 through the power supply via. Multiple full-pitch distributed lap windings 26 are evenly distributed around the stator yoke 10 to ensure the uniformity and stability of the magnetic field. The electrical angle difference between the full-pitch distributed lap windings 26 is 120 degrees or 240 degrees. Simultaneously, the straight portion of the coil 24 in each phase of the full-pitch distributed lap winding 26, i.e., all portions of the second segment 232, has a width of 60 electrical angles in both the first conductive layer 21 and the second conductive layer 22.

[0093] When an external AC power supply is connected to the three power supply pads 281 of terminal 28, current flows through the three full-pitch distributed lap windings 26, generating a rotating magnetic field. Due to the electrical angle difference of 120 degrees or 240 degrees between the three full-pitch distributed lap windings 26, the generated magnetic field forms a stable rotating magnetic field in the motor air gap. This rotating magnetic field interacts with the permanent magnets on the rotor 30, generating electromagnetic torque and driving the motor. The design of the three-phase full-pitch distributed lap windings 26 allows for smooth current transmission between different conductive layers, enhancing the uniformity and strength of the magnetic field. This design is particularly suitable for high-performance three-phase AC motors, such as those used in robotics and medical equipment. The three-phase full-pitch distributed lap windings 26 can significantly improve the motor's torque density and efficiency, while reducing vibration and noise during operation.

[0094] In other embodiments, the full-pitch distributed lap winding 26 may also be in the form of single-phase, two-phase, or other multi-phase.

[0095] In one embodiment of the present invention, the conductive layer has a midpoint connection hole 27, and multiple wires in the conductive layer are connected in series to form a three-phase full-pitch distributed lap winding 26. All three-phase full-pitch distributed lap windings 26 are electrically connected to the midpoint connection hole 27, and the connection method of the three-phase full-pitch distributed lap windings 26 is Y-shaped.

[0096] The three-phase full-pitch distributed lap windings 26 are connected in a Y-shape (star configuration), meaning that one end of each full-pitch distributed lap winding 26 is connected to a power supply pad 281 (e.g., A, B, C), and the other end is connected to a common midpoint (neutral point). This connection method ensures that the electrical angle difference between each full-pitch distributed lap winding 26 is 120 degrees, forming a standard three-phase AC motor winding structure.

[0097] A center connection hole 27 is formed on the surface of the flexible circuit board 20 to connect the common terminals of the three full-pitch distributed lap windings 26 together. The center connection hole 27 is located at the center of the flexible circuit board 20, but it can also be located on the side of the flexible circuit board 20 near the terminal 28. This center connection hole 27 is copper-plated to ensure good conductivity and mechanical strength. One end of each phase full-pitch distributed lap winding 26 is electrically connected to the corresponding power supply pad 281 through a conductive via 25, and the other end is connected to the center connection hole 27 through a wire 23. This design ensures that the current is evenly distributed among the full-pitch distributed lap windings 26 and forms a stable Y-shaped connection.

[0098] In one embodiment of the present invention, the stator structure 1 further includes a magnetic field detection component 40, which includes a circuit control board 41 and a Hall sensor 42.

[0099] Hall sensor 42 is mounted on circuit control board 41, which is connected to the side of flexible circuit board 20 with terminal 28. Flexible circuit board 20 is wound to form a cylindrical stator winding. Circuit control board 41 is annular in shape. After flexible circuit board 20 is wound to form a cylindrical stator winding, circuit control board 41 is positioned as a cover at the opening of stator winding. Positioning groove is provided on the outer periphery of circuit control board 41, and positioning teeth are provided at the opening of stator winding. Positioning teeth are confined within positioning groove. Hall sensor 42 is used to detect the magnetic field of rotor 30 during motor operation, and then detect the angle of rotor 30.

[0100] In one embodiment, the circuit control board 41 is also flexible, allowing it to be folded and placed over the opening of the stator winding. The circuit control board 41 is positioned on the side of the flexible circuit board 20 near the terminal 28, facilitating electrical connection between the circuit control board 41 and an external power source via the terminal 28. In addition to pins for the power positive terminal, ground, and signal output, the Hall sensor 42 also includes pins for control signals and speed signals. Therefore, the Hall sensor 42 requires multiple external connection lines. By designing the circuit control board 41 as flexible, it can be integrated with the flexible circuit board 20 during manufacturing, allowing the Hall sensor 42 to be electrically connected to an external circuit via the terminal 28. This significantly improves motor space utilization, reduces structural volume, and enhances wiring convenience.

[0101] Multiple Hall effect sensors 42 are arranged at circumferential intervals along the circuit control board 41 to improve the detection accuracy of the magnetic field at different positions of the rotor 30 by the magnetic field detection assembly 40. Multiple positioning grooves are formed on the outer periphery of the annular circuit control board 41, and multiple positioning teeth protrude from one side of the flexible circuit board 20. All positioning teeth and the circuit control board 41 are located on the same side of the flexible circuit board 20. When the circuit control board 41 covers the opening of the stator winding, each positioning tooth and the positioning groove of the circuit control board 41 engage, allowing the circuit control board 41 to be precisely installed on the stator winding, thereby improving the accuracy and stability of the Hall effect sensors 42 in detecting the magnetic field of the rotor 30 during motor operation.

[0102] The stator windings described above are Y-connected in a three-phase system, but a delta connection can also be used (Figure 17 shows the delta connection of the stator windings). The full-pitch distributed lap winding 26 has one pole pair, but this can be extended to other pole pairs. The number of turns in the full-pitch distributed lap winding 26 can exceed two, either partially or entirely, to increase the total number of turns. The number of conductive layers in the flexible circuit board 20 can be two or more. Similarly, the full-pitch distributed lap winding 26 can be formed in single-phase, two-phase, or other multi-phase configurations.

[0103] The present invention also proposes an AC motor, which includes a rotor and a stator structure. The specific structure of the stator structure is as described in the above embodiments. Since the AC motor adopts all the technical solutions of all the above embodiments of the stator structure, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be described in detail here.

[0104] The rotor is rotatably housed within a cavity, with a flexible circuit board surrounding its outer periphery. The rotor is located within a cavity formed inside the stator yoke and can rotate freely. The rotor can be a permanent magnet rotor or an induction rotor, depending on the application requirements.

[0105] The flexible circuit board surrounds the outer periphery of the rotor, allowing the magnetic field generated by the stator windings to act efficiently on the rotor. This design not only simplifies the installation process but also reduces the structural volume occupied by the stator windings, improving the ease of processing and assembly.

[0106] The above description is merely an exemplary embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's specification and drawings under the technical concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A stator structure, characterized in that, The stator structure includes: A stator yoke, wherein a cavity is formed inside the stator yoke that extends through both ends; and A flexible circuit board is wound and attached to the cavity wall. The flexible circuit board includes at least two conductive layers. Each conductive layer has multiple wires. The wires in one conductive layer are electrically connected to the wires in the other conductive layer and surround to form a coil. There are multiple coils. The multiple coils are arranged at intervals along the circumference of the stator yoke and are all electrically connected to the terminal.

2. The stator structure as described in claim 1, characterized in that, Multiple sets of the aforementioned coils are connected in series to form a full-pitch distributed lap winding; The flexible circuit board includes a first conductive layer and a second conductive layer. Multiple conductive vias are formed on the edges of both the first and second conductive layers. A wire in the first conductive layer is electrically connected to a wire in the second conductive layer through a conductive via located on the edge of the flexible circuit board. A wire in the second conductive layer is electrically connected to another wire in the first conductive layer through a conductive via located on the other edge of the flexible circuit board. Another wire in the first conductive layer is electrically connected to another wire in the second conductive layer through a conductive via located on the edge of the flexible circuit board. The plurality of wires in the first conductive layer are sequentially and alternately connected to the plurality of wires in the second conductive layer to form a phase full-pitch distributed lap winding.

3. The stator structure as described in claim 2, characterized in that, The conductor includes at least a first segment, a second segment, and a third segment connected in sequence. The second segment is parallel to the axis of the stator yoke. The first segment and the third segment are inclined in different directions relative to the second segment. The multiple conductors in each conductive layer are arranged at intervals along the circumference of the stator yoke.

4. The stator structure as described in claim 3, characterized in that, At least one first segment in the first conductive layer and at least one first segment in the second conductive layer are arranged to intersect along a projection perpendicular to the surface of the flexible circuit board; at least one third segment in the first conductive layer and at least one third segment in the second conductive layer are arranged to intersect along a projection perpendicular to the surface of the flexible circuit board.

5. The stator structure as described in claim 4, characterized in that, The multiple second segments in the first conductive layer and the multiple second segments in the second conductive layer are evenly arranged at projection intervals perpendicular to the surface of the flexible circuit board, and the two ends of the flexible circuit board abut against and are wound and attached to the inner wall of the stator yoke.

6. The stator structure as described in claim 4, characterized in that, The multiple second segments in the first conductive layer coincide with the multiple second segments in the second conductive layer along the projection portion perpendicular to the surface of the flexible circuit board, or the spacing between some lines is small, and the two ends of the flexible circuit board partially overlap and are wound and attached to the inner wall of the stator yoke.

7. The stator structure as described in any one of claims 3 to 6, characterized in that, The line width of the second segment is greater than that of the first segment and the third segment.

8. The stator structure as described in any one of claims 3 to 6, characterized in that, The flexible circuit board is polygonal in shape, and the wires are parallel to the sides of adjacent flexible circuit boards. Alternatively, the flexible circuit board may be rectangular in shape, with the conductors forming right angles near the corners of the flexible circuit board to fully utilize the space of the rectangular flexible circuit board.

9. The stator structure as described in any one of claims 1 to 6, characterized in that, The conductive layer has a midpoint connection hole, and multiple wires in the conductive layer are connected in series to form a three-phase full-pitch distributed lap winding. All three phases of the full-pitch distributed lap winding are electrically connected to the midpoint connection hole, and the connection method of the three phases of the full-pitch distributed lap winding is Y-shaped.

10. An AC motor, characterized in that, The AC motor includes a rotor and a stator structure as described in any one of claims 1 to 9; the rotor is rotatably disposed within the cavity, and the flexible circuit board surrounds the outer periphery of the rotor.

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