Stator winding and air core cup motor

Abstract

The application provides a kind of stator winding and hollow cup motor, specifically relates to micro motor technical field, the stator winding includes: flexible printed circuit board, the flexible printed circuit board is wound, forms multilayer winding drum;The flexible printed circuit board includes substrate and multiple tracks formed on the substrate, each track includes multiple track segments connected in chain, any two connected track segments in the multiple track segments are distributed on different sides of the substrate;The distance between adjacent track segments on the same side of the substrate is consistent, the line width of the track segment is positively correlated with the radial curvature radius of the flexible printed circuit board at the track segment, so that the track segments on the multilayer winding drum are aligned one by one.The application positively correlates the line width of track segment with the radial curvature radius of flexible printed circuit board at the track segment, accurately offsets the cumulative effect of outer layer circumference when multilayer winding, and significantly improves slot fill rate.

Description

Technical Field

[0001] This application relates to the field of micro motor technology, and in particular to a stator winding and a hollow cup motor. Background Technology

[0002] Traditional miniature hollow cup motors typically use hand- or machine-wound copper wire coils for their stator windings. While these offer certain advantages in electromagnetic performance, their inherent bulkiness and complex manufacturing processes severely restrict the miniaturization of motors. With the surge in demand for ultra-small motors in fields such as microrobotics and portable medical devices, the limitations of traditional copper wire windings are becoming increasingly apparent. Particularly in the field of artificial organs, such as the development of artificial hearts, extremely high demands are placed on the size, efficiency, reliability, and biocompatibility of drive motors. Traditional motors, due to their large size, high energy consumption, and difficulty in seamlessly integrating with biological tissues, cannot meet the needs of miniature medical devices such as artificial hearts. Therefore, developing a small, lightweight, efficient, and biocompatible miniature motor has become a current research hotspot.

[0003] Flexible printed circuit boards (FPCs), as a novel electronic material, have been widely used in microelectronic devices due to their thinness, flexibility, ease of integration, and good biocompatibility. FPCs not only enable precise layouts of complex circuits but also adapt to various irregular spatial arrangements through their flexibility, providing new ideas for designing miniaturized, high-performance coreless motors. However, because the perimeter of each layer increases linearly with the radius during the FPC rolling process, redundancy in the outer copper wires occurs, and the phase arrangement after rolling is difficult to control precisely, leading to deterioration in electromagnetic performance. To address the aforementioned problems caused by the cumulative perimeter effect of multi-layer rolled structures, existing technologies adjust the distance between each copper wire. However, as the perimeter accumulates, the distance between the copper wires also accumulates, resulting in a low slot fill factor. Utility Model Content

[0004] To address at least one drawback of the prior art, this application provides a stator winding, comprising:

[0005] A flexible printed circuit board (PCB) is wound to form a multi-layer roll. The PCB includes a substrate and multiple traces formed on the substrate. Each trace includes multiple trace segments connected in a chain. Any two connected trace segments are distributed on different sides of the substrate. The distance between adjacent trace segments on the same side of the substrate remains consistent. The linewidth of each trace segment is positively correlated with the radial radius of curvature of the PCB at the trace segment, so that the trace segments on the multi-layer roll are aligned one by one.

[0006] Optionally, for each layer of the roll, the line width of the trace segment on the roll is positively correlated with the radial radius of the roll; a coupling zone is formed between any two adjacent layers of the multi-layer roll, and the line width of the trace segment on the coupling zone is positively correlated with the difference in circumferential circumference between the two adjacent layers of the coupling zone.

[0007] Optionally, the trace segments are connected by conductive connectors that penetrate the substrate; the dimensions of the multiple conductive connectors on the traces are positively correlated with the resistance value of the traces in a first direction to balance the resistance differences between the multiple traces; the first direction is perpendicular to the current flow direction between the trace segments.

[0008] Optionally, the conductive connector includes conductive posts and bridging traces at both ends of the conductive posts for connecting the trace segments, wherein the number of conductive posts corresponding to the conductive connector matches the size of the bridging traces in the first direction.

[0009] Optionally, the outer layer of the multi-layer spool includes a winding start end, a winding end end, and a gap adjustment area near the winding end end. The line width of the trace segment in the gap adjustment area is smaller than the line width of the trace segments in other areas of the outer layer spool except for the gap adjustment area, so that a circumferential open gap with a preset unfolding angle is formed between the winding end end and the winding start end. The radial radius of the outer layer spool is larger than the radial radius of each layer spool in the multi-layer spool except for the outer layer spool.

[0010] Optionally, the size of the conductive connector corresponding to at least one trace segment in the gap adjustment area in the first direction is greater than the average size of the conductive connectors corresponding to trace segments in other areas of the outer roll besides the gap adjustment area in the first direction.

[0011] Optionally, the flexible printed circuit board includes a first flexible section for forming an inner layer roll in the multilayer roll, and a second flexible section for forming each layer roll other than the inner layer roll in the multilayer roll; a first insulating layer is provided on both sides of the substrate of the first flexible section, such that the corresponding trace segment is located between the substrate and the first insulating layer; a second insulating layer is provided on the side of the substrate of the second flexible section away from the inner layer roll, such that the corresponding trace segment is located between the substrate and the second insulating layer; the radial radius of the inner layer roll is smaller than the radial radius of each layer roll other than the inner layer roll in the multilayer roll.

[0012] Optionally, the trace segment includes multiple conductive segments connected in a chain, and the multiple conductive segments are arranged non-collinearly.

[0013] Optionally, the flexible printed circuit board further includes a lead-out line corresponding to each trace, the lead-out line being disposed on the substrate, one end of each trace being connected to one end of the corresponding lead-out line, and the other end of the lead-out line extending out of the circumferential boundary of the multilayer roll; multiple lead-out lines are evenly distributed on the circumferential boundary of any layer of the roll.

[0014] On the other hand, this application provides a hollow cup motor, including any of the above-mentioned optional stator windings.

[0015] By adopting the above technical solution, this application has the following beneficial effects:

[0016] This application provides a stator winding that uses a flexible printed circuit board (PCB) rolled into a circle as the stator winding. This achieves miniaturization and weight reduction of the motor stator structure. By ensuring a positive correlation between the trace width and the radial radius of curvature of the PCB at that trace segment (i.e., the trace width increases linearly with the radial radius of curvature), and with consistent trace segment spacing, the cumulative effect of the outer layer circumference during multi-layer rolling is precisely offset. This eliminates conductor redundancy and corrects distribution distortion, enabling precise phase matching of each winding layer in three-dimensional space after winding, significantly improving slot fill factor. Simultaneously, the optimized trace layout enhances heat dissipation efficiency, effectively preventing runaway temperature rise issues in micromotors. The manufacturing of this stator winding utilizes repeatable printed circuit technology, simplifying the manufacturing process, reducing development costs, and improving yield.

[0017] Other features and advantages of this application will be described in detail in the following detailed description section. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. The same reference numerals usually represent the same components. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the structure of a flexible printed circuit board provided in an embodiment of this application;

[0020] Figure 2 This is a schematic diagram of a stator winding structure provided in an embodiment of this application;

[0021] Figure 3 This is a schematic diagram of the layered structure of a flexible printed circuit board provided in an embodiment of this application;

[0022] Figure 4 This is a schematic diagram of a trace distribution provided in an embodiment of this application;

[0023] Figure 5 This is a trace distribution perspective view provided in an embodiment of this application;

[0024] Figure 6 This is provided by the embodiments of this application. Figure 4 Enlarged view of point A in the middle;

[0025] Figure 7 This is provided by the embodiments of this application. Figure 4 Enlarged view of point B in the middle;

[0026] Figure 8 This is another schematic diagram of trace distribution provided in an embodiment of this application;

[0027] Figure 9 This is provided by the embodiments of this application. Figure 8 Enlarged view of point C in the middle;

[0028] Figure 10 This is provided by the embodiments of this application. Figure 4 Enlarged view of point D in the middle;

[0029] Figure 11 This is provided by the embodiments of this application. Figure 8 Enlarged view of point E in the middle;

[0030] Figure 12 This is a schematic diagram of the structure of a trace segment provided in an embodiment of this application.

[0031] The following is supplementary explanation of the attached figures:

[0032] 100 - Flexible printed circuit board, 110 - Substrate, 120 - Trace, 121 - Trace segment, 121a, 121b, 121c, 121d - Conductive segment, 130 - Conductive connector, 131 - Conductive post, 132 - Bridge trace, 140 - Winding termination end, 150 - Gap adjustment area, 160 - First flexible segment, 161 - First insulating layer, 170 - Second flexible segment, 171 - Second insulating layer, 180 - Lead wire, 200 - Sleeve. Detailed Implementation

[0033] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0034] The term "an embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of this application. In the description of this application, it should be understood that the terms "upper," "lower," "top," "bottom," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. Moreover, the terms "first," "second," etc., are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein.

[0035] refer to Figure 1 This application provides a stator winding, including a flexible printed circuit board 100. The flexible printed circuit board 100 is wound to form a multi-layered roll; the flexibility of the flexible printed circuit board 100 allows it to adapt to complex geometries, especially in miniature hollow cup motors, where it can perfectly fit the internal cavity structure of the motor, ensuring the stability of electrical performance. By cleverly utilizing the conductivity and flexibility of the FPC, the size of the miniature hollow cup motor can be further reduced while still meeting the motor performance requirements, achieving miniaturization, lightweighting, and high efficiency of the motor stator. In specific implementations, such as... Figure 2 As shown, the flexible printed circuit board 100 is rolled up inside the sleeve 200 along the inner diameter of the sleeve 200 to form a multi-layered cylindrical structure.

[0036] refer to Figures 3-5The flexible printed circuit board 100 includes a substrate 110 and multiple traces 120 formed on the substrate 110. In specific embodiments, the substrate 110 may be made of polyimide (PI) material, providing mechanical support and electrical insulation. The traces 120 are conductive traces, such as copper wires, arranged on both sides of the substrate 110 to form a double-sided wiring structure. The multiple traces 120 are connected at one end to a common connection point via a star connection or cross connection, forming a neutral point. For example, in a three-phase motor, the three traces converge at one end to a common connection point. The other end of each trace 120 is connected to a lead 180, which is used to connect to external circuitry to ensure current input and output. Each trace 120 includes multiple chain-connected trace segments 121, with any two connected trace segments 121 distributed on different sides of the substrate 110. The number of slots and turns of the traces 120 on the flexible printed circuit board 100 are defined. The number of slots Z is determined by the motor design and is an integer multiple of the number of winding phases. For example, in the case of a three-phase winding, the number of slots Z is an integer multiple of 3. The number of turns N is usually between 1 and 50. The number of trace segments 121 on one layer of the roll is Z*N. The number of roll layers T is determined by the motor design and is between 1 and 10. Therefore, the total number of turns of the entire flexible printed circuit board 100 is Z*N*T. The total number s of trace segments 121 on the flexible printed circuit board 100 satisfies: s = Z·N·T. The attached figure shows 6 slots, 4 turns, and 3 loops. Therefore, the total number s of trace segments 121 on the flexible printed circuit board 100 is 72 turns. The chain-connected trace segments 121 are used to ensure the continuity of current in the multi-layer rolls. Double-sided wiring achieves more turns in a limited space, improves the slot fill factor, avoids local stress concentration caused by single-sided wiring, improves structural stability, reduces electromagnetic interference between adjacent traces, and improves motor performance. The distance between adjacent trace segments 121 on the same side of the substrate 110 remains consistent. Due to the symmetry of the double-sided wiring, the distance between trace segments 121 on both sides of the substrate 110 remains consistent. Consistent spacing ensures that the current is evenly distributed among the trace segments 121, avoiding local overheating or excessive current density. This facilitates production through standardized manufacturing processes (such as photolithography and etching), improving production efficiency, yield, and product consistency.

[0037] The spacing between each trace segment 121 remains the same. However, if all trace segments 121 have the same linewidth, the phase positions of each turn after winding will not align. Therefore, to ensure the stator generates a consistent magnetic field angle and meets the motor's performance requirements, the linewidth needs to be adjusted to address the cumulative circumference effect of the multi-layer winding structure. This ensures the total length of the flexible printed circuit board 100 precisely matches the multi-layer spiral assembly requirements of the sleeve 200's inner cavity. Specifically, since the circumference of each layer increases linearly with the radius during winding, a constant linewidth would result in redundancy in the outer trace segments 121. The linewidth of the trace segment 121 is positively correlated with the radial radius of curvature of the flexible printed circuit board 100 at the trace segment 121. Increasing the outer layer linewidth layer by layer precisely offsets this cumulative effect, ensuring that the trace segments 121 on the multi-layer winding are aligned one-to-one, guaranteeing phase consistency across all winding layers.

[0038] In specific implementation, the linewidth of the trace segment 121 is designed according to the inner diameter of the sleeve 200. The inner diameter of the sleeve 200 determines the radial radius of the multi-layer roll after winding, which affects the circumference of one layer of roll, thus affecting the linewidth design of the trace segment 121. When designing the linewidth of the trace segment 121, the distance between the first or last trace segment 121 on the flexible printed circuit board 100 and the edge of the flexible printed circuit board 100 must also be considered. Typically, the linewidth of the trace segment 121 closest to this edge is adjusted to accommodate this edge distance, ensuring that the length of the flexible printed circuit board 100 matches the number of roll layers. Specifically, the linewidth W of the trace segment 121, the number n of trace segments 121 on each roll layer, the number n1 of trace segments 121 on each roll layer used to accommodate the aforementioned edge distance, and the linewidth W of the trace segments 121 used to accommodate the aforementioned edge distance are all considered. end The following conditions must be met between the spacing t of the trace segments 121, the edge distance k, and the perimeter l of one layer of the roll: W·(n-n1)+n1·W end +n·t+k=l. Where l can be calculated based on the inner diameter of sleeve 200, t can be adjusted according to the process, and n1 corresponding to each layer of the roll is usually different. For example, n1 is 1 on the inner layer of the roll, n1 is 4 on the outer layer of the roll, and n1 is 0 on other layers of the roll.

[0039] Specifically, in this embodiment, by progressively increasing the linewidth of the outer layer trace segments 121, the cumulative effect of the outer layer circumference during multi-layer winding is precisely offset while maintaining consistent trace segment spacing. This ensures precise alignment of each layer of trace segments 121 in three-dimensional space, thereby ensuring phase consistency of each layer of windings and preventing electromagnetic performance degradation caused by phase misalignment. Aligned trace segments 121 also enhance magnetic field coupling efficiency, improving the motor's electromagnetic performance. Uniform wiring optimizes heat dissipation paths, preventing localized overheating and extending the motor's lifespan. By dynamically adjusting the linewidth, a higher slot fill factor can be achieved within a limited space, further increasing the motor's power density.

[0040] In one possible implementation, for each layer of the roll, the linewidth of the trace segment 121 on the roll is positively correlated with the radial radius of the roll; a coupling zone is formed between any two adjacent layers of the roll in the multi-layer roll, and the linewidth of the trace segment 121 on the coupling zone is positively correlated with the difference in circumferential circumference between the two adjacent layers of the roll corresponding to the coupling zone.

[0041] Taking a three-layer roll as an example, the trace segment 121 on the inner roll uses a narrow linewidth of 0.3mm-0.4mm to adapt to the small radius. The linewidth of the trace segment 121 located in the coupling area between the inner and middle rolls is increased to 0.4mm-0.5mm to compensate for the difference in the closed-loop circumference of the inner layer. The linewidth of the trace segment 121 on the middle roll is increased to 0.35mm-0.45mm to adapt to the radius increment of the middle layer. The linewidth of the trace segment 121 located in the coupling area between the middle and outer rolls jumps to 0.45mm-0.55mm to offset the circumference deviation of this layer. The linewidth of the trace segment 121 on the outer roll is widened to 0.4mm-0.5mm to match the maximum radius, so that the total length strictly terminates at the third turn. This achieves a redundancy-free arrangement of coils within the space of the sleeve 200, breaking through the spatial adaptation limit of traditional flexible circuits.

[0042] Specifically, in this embodiment, the linewidth of the trace segment 121 of each layer of the roll increases linearly with the radial radius of the roll. The linewidth of the trace segment 121 on the coupling region is positively correlated with the difference in circumferential circumference between adjacent layers of the roll, ensuring that the trace segments of adjacent layers of the roll are precisely aligned after winding, avoiding phase misalignment caused by circumference difference. While achieving miniaturization and lightweighting, this solves the technical problem caused by the cumulative circumference effect in multi-layer rolled structures, optimizes electromagnetic performance, and significantly improves slot fill factor and heat dissipation efficiency. It not only meets the performance requirements of micro motors but also simplifies the manufacturing process, reduces development costs, and provides feasibility for the industrialization of micro hollow cup motors.

[0043] In one possible implementation, the trace segments 121 are connected by conductive connectors 130 penetrating the substrate 110; the dimensions of the plurality of conductive connectors 130 on the trace 120 are positively correlated with the resistance value of the trace 120 in a first direction to balance the resistance differences between the multiple traces 120; the first direction is perpendicular to the current flow direction between the trace segments 121. Specifically, larger conductive connectors 130 can reduce resistance, while smaller ones will increase resistance.

[0044] Optional, see reference Figure 6 The conductive connector 130 is a conductive post 131, such as a copper post. A larger diameter conductive post 131 can reduce resistance, while a smaller diameter conductive post 131 will increase resistance.

[0045] Optional, continue to refer to Figure 6The conductive connector 130 includes conductive posts 131 and bridging traces 132 at both ends of the conductive posts 131 for connecting trace segments 121. The number of conductive posts 131 corresponding to the conductive connector 130 matches the size of the bridging traces 132 in a first direction. Specifically, the conductive posts 131 penetrate the substrate 110, and both ends of the conductive posts 131 are connected to the corresponding trace segments 121 via the bridging traces 132. For example, a larger diameter of the conductive posts 131 and a wider bridging trace 132 can reduce resistance, while a smaller size will increase resistance; increasing the number of conductive posts 131 can reduce resistance, while decreasing the number of conductive posts 131 will increase resistance.

[0046] In specific implementations, some bridge traces 132 are provided with at least two conductive posts 131. Compared to bridge traces 132 with only one conductive post 131, the multi-conductive-post structure can further reduce bridge resistance, thereby improving the performance of the circuit board. However, considering the safety distance limitation between the bridge trace 132 and the edge line, a smaller bridge trace 132 can only support one conductive post 131. For example, conductive posts 131 of different diameters can be used to select according to the different line widths of the trace segment 121 and the size of the bridge trace 132, thereby minimizing resistance within the allowable size range and ensuring a certain safety distance between the conductive post 131 and the adjacent edge line. By optimizing the size of the conductive connector 130, the impedance during current flow is reduced, improving motor efficiency; by using different widths of the bridge trace 132 and different diameters and numbers of conductive posts 131, the problem of large resistance differences between traces 120 when the trace segment 121 has different line widths is solved.

[0047] Specifically, in this embodiment, the size of the conductive connector 130 directly affects the resistance value of the trace 120. By adjusting the size of the conductive connector 130, the resistance difference between multiple traces 120 is balanced, achieving a balanced three-phase resistance distribution, ensuring uniform current distribution between each trace segment, avoiding local overheating or excessive current density, and improving the reliability and performance of the motor.

[0048] In one possible implementation, the outer drum in a multi-layer spool includes a winding start end, a winding end 140, and a gap adjustment region 150 near the winding end 140. The linewidth of the trace segment 121 in the gap adjustment region 150 is smaller than the linewidth of the trace segment 121 in other areas of the outer drum except for the gap adjustment region 150, so that a circumferential open gap with a preset unfolding angle is formed between the winding end 140 and the winding start end; the radial radius of the outer drum is larger than the radial radius of each drum in the multi-layer spool except for the outer drum. Specifically, refer to... Figure 4 , Figure 7By reducing the linewidth of the trace segments 121 in the gap adjustment area 150 and adjusting their bending angle, the length of the flexible printed circuit board 100 is reduced without reducing the number of trace segments 121. This allows for the formation of a circumferential open gap with a preset unfolding angle, such as 10°, between the winding termination end 140 and the winding start end. This gap is used to place the wire harness to achieve specific functional requirements. (Reference) Figure 8 , Figure 9 In designs where no wire harness is required, this gap can be omitted. That is, the line width of the trace segment 121 in the gap adjustment area 150 is consistent with the line width of the trace segment 121 in other areas of the outer drum except for the gap adjustment area 150. At the same time, the bending angle of the trace segment 121 in the gap adjustment area 150 is consistent with the bending angle of the trace segment 121 in other areas except for the gap adjustment area 150.

[0049] For example, when no wire harness is needed, the line width of the trace segment 121 on the outer drum is widened to 0.4mm-0.5mm to match the radius of the outer drum; when a wire harness is needed, the line width of the trace segment 121 in areas other than the gap adjustment area 150 on the outer drum is set to 0.4mm-0.5mm to match the radius of the outer drum, and the line width of the trace segment 121 in the gap adjustment area 150 is reduced to 0.25mm-0.35mm. The number of trace segments 121 in the gap adjustment area 150, i.e., the range of the gap adjustment area 150, can be flexibly adjusted as needed. For example, the number of trace segments 121 in the gap adjustment area 150 is 4.

[0050] Furthermore, the narrowing of the linewidth of the trace segment 121 in the gap adjustment region 150 will increase the resistance of this portion of the trace segment 121, thereby degrading the performance of the FPC. Therefore, to compensate for this resistance value, the dimension of the conductive connector 130 corresponding to at least one trace segment 121 in the gap adjustment region 150 in the first direction is larger than the average dimension of the conductive connector 130 corresponding to the trace segment 121 in other areas on the outer roll excluding the gap adjustment region 150 in the first direction. By increasing the size of the conductive connector 130, the resistance of the gap adjustment region 150 can be reduced, compensating for the increase in resistance caused by the reduction in linewidth, ensuring uniform current distribution among the trace segments, and avoiding local overheating or excessively high current density. For example, refer to Figure 10 The line width of the bridging trace 132 corresponding to at least one trace segment 121 in the gap adjustment zone 150 is greater than the line width of the bridging trace 132 corresponding to trace segments 121 outside the gap adjustment zone 150. Accordingly, refer to Figure 11In designs where no wire harness is required, since the line width of the trace segment 121 in the gap adjustment area 150 is consistent with the line width of the trace segment 121 in other areas of the outer drum except for the gap adjustment area 150, the line width of the bridging trace 132 corresponding to the trace segment 121 in the gap adjustment area 150 is also consistent with the line width of the bridging trace 132 corresponding to the trace segment 121 outside the gap adjustment area 150.

[0051] Specifically, in this embodiment, a gap adjustment area 150 is provided on the outer layer of the multi-layer roll, and the line width of the trace segment 121 of the gap adjustment area 150 is reduced to form a circumferential open gap with a preset unfolding angle for placing the wire harness and meeting specific functional requirements. At the same time, by increasing the size of the conductive connector 130, the increase in resistance caused by the reduction in line width is compensated, ensuring uniform current distribution and optimized electromagnetic performance.

[0052] In one possible implementation, refer to Figure 1 , 3 The flexible printed circuit board 100 includes a first flexible section 160 for forming an inner layer roll in a multilayer roll, and a second flexible section 170 for forming each layer roll other than the inner layer roll in the multilayer roll. A first insulating layer 161 is provided on both sides of the substrate 110 of the first flexible section 160, such that a corresponding trace segment 121 is located between the substrate 110 and the first insulating layer 161. A second insulating layer 171 is provided on the side of the substrate 110 of the second flexible section 170 away from the inner layer roll, such that a corresponding trace segment 121 is located between the substrate 110 and the second insulating layer 171. The radial radius of the inner layer roll is smaller than the radial radius of each layer roll other than the inner layer roll in the multilayer roll. The first flexible section 160 adopts a double-sided insulating encapsulation structure, and its total thickness is one more first insulating layer 161 than the single-sided insulating encapsulation structure of the second flexible section 170.

[0053] Specifically, the insulating layer on the first side of the substrate 110 only includes the first insulating layer 161 of the first flexible section 160, while the second flexible section 170 is not covered by an insulating layer; the insulating layer on the second side of the substrate 110 includes the first insulating layer 161 of the first flexible section 160 and the second insulating layer 171 of the second flexible section 170. When the flexible printed circuit board 100 is wound, the first side of the substrate 110 faces inward, and the second side of the substrate 110 faces outward. The first insulating layer 161 on the first side serves as the inner insulating layer of the inner layer roll, the first insulating layer 161 on the second side serves as the outer insulating layer of the inner layer roll, and the inner insulating layer of the adjacent layer rolls of the inner layer roll, and the second insulating layer 171 on the second side serves as the outer insulating layer of the outer layer roll, and the insulating layer between each layer roll except for the inner layer roll.

[0054] Specifically, in this embodiment, by dividing the flexible printed circuit board 100 into a first flexible section 160 and a second flexible section 170, and adopting a double-sided / single-sided differentiated insulation section layout, electrical isolation between each layer trace segment 121 is ensured to prevent short circuits, and the flexible deformation capability is optimized while ensuring electrical safety.

[0055] In one possible implementation, trace segment 121 includes a plurality of conductive segments connected in a chain, the plurality of conductive segments being arranged non-collinearly among themselves.

[0056] Specifically, in this embodiment of the application, the trace segment 121 is designed as a plurality of non-collinearly arranged conductive segments. For example, refer to... Figure 12 The trace segment 121 includes conductive segments 121a, 121b, 121c, and 121d. These conductive segments are connected in a chain to form a complete trace segment 121. The conductive segments are arranged in a non-collinear manner to form a tortuous path. Compared with three-segment, two-segment, or straight trace segments, the multi-segment structure with non-collinear arrangement increases the effective magnetic density and reduces the resistance. It optimizes the ratio of effective magnetic density to resistance, improves the power density and efficiency of the motor, and thus makes the motor performance more efficient.

[0057] In one possible implementation, the flexible printed circuit board 100 further includes a lead 180 corresponding to each trace 120. The lead 180 is disposed on the substrate 110. One end of each trace 120 is connected to one end of the corresponding lead 180. The other end of the lead 180 extends out of the circumferential boundary of the multi-layer roll for connecting external circuits and ensuring current input and output. Considering the special requirements when the flexible printed circuit board 100 is rolled up, the multiple leads 180 are distributed at equal intervals on the flexible printed circuit board 100. After the flexible printed circuit board 100 is rolled up, the multiple leads 180 are evenly distributed on the circumferential boundary of any layer of the roll.

[0058] Taking a three-phase motor as an example, refer to Figure 1 , 2 The three leads 180 correspond to the U, V, and W phases of the motor, respectively. To ensure that the three leads 180 are equidistant after being rolled up and that their included angles relative to the center of the circle are 120°, the three leads 180 are evenly distributed on the flexible printed circuit board 100. This ensures the uniform distribution of the leads 180 after the flexible printed circuit board 100 is rolled up and also improves the stability and reliability of the flexible printed circuit board 100 in the rolled-up state.

[0059] Specifically, in this embodiment of the application, by setting the lead-out line 180 corresponding to each trace 120 on the flexible printed circuit board 100 and adopting an equal spacing design, the uniform distribution of the lead-out lines after the flexible printed circuit board 100 is rolled up is ensured, thereby optimizing the electrical and electromagnetic performance.

[0060] On the other hand, a hollow cup motor is also provided, including the stator windings provided in any of the above embodiments.

[0061] In summary, this application constructs a miniature hollow cup motor winding using a flexible printed circuit, combining different linewidth strategies, a split-type insulation packaging design, and a multi-size bridging connection design to achieve precise adaptation of multi-layer spiral windings within a miniaturized space. Specifically, by ensuring a positive correlation between the trace segment linewidth and the radial radius of curvature of the flexible printed circuit board at that trace segment (i.e., the trace segment linewidth increases linearly with the radial radius of curvature), and with consistent trace segment spacing, the cumulative effect of the outer layer circumference during multi-layer winding is precisely offset, eliminating conductor redundancy and correcting distribution distortion. This allows for precise phase matching of each winding layer in three-dimensional space after winding, significantly improving slot fill factor. Simultaneously, the optimized trace layout enhances heat dissipation efficiency, effectively preventing micro-motor temperature rise runaway issues. The double-sided / single-sided differentiated insulation section layout optimizes flexible deformation capability while ensuring electrical safety; conductive connectors of different diameters reduce local resistance, and combined with the segmented trace segment structure, the ratio of effective magnetic density to the square root of resistance of the winding is increased, improving performance. Compared to traditional FPC winding solutions, this application breaks through the spatial adaptability limits in miniaturization scenarios, and combines the advantages of high-precision winding and power density, providing a winding solution with industrial feasibility for miniature hollow cup motors.

[0062] In this application, unless otherwise expressly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the connection within two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0063] It should be noted that the order of the embodiments described above is merely for descriptive purposes and does not represent the superiority or inferiority of the embodiments. Furthermore, while this specification describes specific embodiments, other embodiments are also within the scope of the appended claims. In some cases, the actions or steps described in the claims can be performed in the order shown in different embodiments and still achieve the desired results. Additionally, the processes depicted in the drawings do not necessarily require a specific order or sequence of connections to achieve the desired results; in some implementations, parallel processing of multiple tasks is possible or may be advantageous.

[0064] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. The focus of each embodiment is to describe the differences from other embodiments.

[0065] The above are merely preferred embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A stator winding, characterized in that, Includes a flexible printed circuit board (100), which is wound to form a multi-layer roll; The flexible printed circuit board (100) includes a substrate (110) and multiple traces (120) formed on the substrate (110). Each trace (120) includes multiple trace segments (121) connected in a chain. Any two connected trace segments (121) are distributed on different sides of the substrate (110). The distance between adjacent trace segments (121) on the same side of the substrate (110) is consistent. The linewidth of the trace segment (121) is positively correlated with the radial radius of curvature of the flexible printed circuit board (100) at the trace segment (121), so that the trace segments (121) on the multilayer roll are aligned one by one.

2. The stator winding according to claim 1, characterized in that, For each layer of the roll, the line width of the trace segment (121) on the roll is positively correlated with the radial radius of the roll; a coupling zone is formed between any two adjacent layers of the multi-layer roll, and the line width of the trace segment (121) on the coupling zone is positively correlated with the difference in circumferential circumference between the two adjacent layers of the coupling zone.

3. The stator winding according to claim 2, characterized in that, The trace segments (121) are connected by conductive connectors (130) penetrating the substrate (110); the dimensions of the plurality of conductive connectors (130) on the trace (120) in a first direction are positively correlated with the resistance value of the trace (120) to balance the resistance differences between the plurality of traces (120); the first direction is perpendicular to the current flow direction between the trace segments (121).

4. The stator winding according to claim 3, characterized in that, The conductive connector (130) includes a conductive post (131) and a bridging trace (132) at both ends of the conductive post (131) for connecting the trace segment (121). The number of conductive posts (131) corresponding to the conductive connector (130) matches the size of the bridging trace (132) in the first direction.

5. The stator winding according to claim 3, characterized in that, The outer layer of the multi-layer spool includes a winding start end, a winding end (140), and a gap adjustment area (150) near the winding end (140). The line width of the trace segment (121) of the gap adjustment area (150) is smaller than the line width of the trace segment (121) of other areas on the outer layer spool except the gap adjustment area (150), so that a circumferential open gap with a preset unfolding angle is formed between the winding end (140) and the winding start end. The radial radius of the outer layer spool is larger than the radial radius of each layer spool in the multi-layer spool except the outer layer spool.

6. The stator winding according to claim 5, characterized in that, The size of the conductive connector (130) corresponding to at least one trace segment (121) of the gap adjustment area (150) in the first direction is greater than the average size of the conductive connector (130) corresponding to trace segments (121) in other areas of the outer roll other than the gap adjustment area (150) in the first direction.

7. The stator winding according to claim 1, characterized in that, The flexible printed circuit board (100) includes a first flexible section (160) for forming an inner layer roll in the multilayer roll, and a second flexible section (170) for forming each layer roll in the multilayer roll other than the inner layer roll; a first insulating layer (161) is provided on both sides of the substrate (110) of the first flexible section (160) so that the corresponding trace segment (121) is located between the substrate (110) and the first insulating layer (161); a second insulating layer (171) is provided on the side of the substrate (110) of the second flexible section (170) away from the inner layer roll so that the corresponding trace segment (121) is located between the substrate (110) and the second insulating layer (171); the radial radius of the inner layer roll is smaller than the radial radius of each layer roll in the multilayer roll other than the inner layer roll.

8. The stator winding according to claim 1, characterized in that, The trace segment (121) includes multiple conductive segments connected in a chain, and the multiple conductive segments are arranged non-collinearly.

9. The stator winding according to claim 1, characterized in that, The flexible printed circuit board (100) also includes a lead-out line (180) corresponding to each trace (120). The lead-out line (180) is disposed on the substrate (110). One end of each trace (120) is connected to one end of the corresponding lead-out line (180), and the other end of the lead-out line (180) extends out of the circumferential boundary of the multilayer roll. The multiple lead-out lines (180) are evenly distributed on the circumferential boundary of any layer of the roll.

10. A hollow cup motor, characterized in that, Includes the stator winding according to any one of claims 1 to 9.

Images