Stator core structure, stator assembly, axial flux machine and robot

Abstract

The application relates to the technical field of electric machines, and discloses a stator core structure, a stator assembly, an axial flux electric machine and a robot. The stator core structure comprises a plurality of tooth portions arranged at intervals in the circumferential direction, and a first tooth shoe ring and a second tooth shoe ring arranged at the axial two ends of the tooth portions and connected with the tooth portions respectively, the two tooth shoe rings connecting the plurality of tooth portions into one body; at least one of the first tooth shoe ring and the second tooth shoe ring is a separate piece arranged separately from the tooth portion and fixedly connected with the tooth portion; the two tooth shoe rings are both provided with a leakage magnetic reduction slot located between the adjacent two tooth portions and extending in the radial direction, and the tooth shoe ring retains a connecting portion connecting the adjacent two tooth portions at the leakage magnetic reduction slot. According to the application, the coil can be directly wound on the exposed tooth portion by arranging at least one side tooth shoe ring separately from the tooth portion; the leakage magnetic reduction slot is arranged on the tooth shoe ring, the leakage between the adjacent tooth portions is reduced while the stator is integrated, and the cogging torque and torque fluctuation of the electric machine are reduced.

Description

Technical Field

[0001] This invention relates to the field of motor technology, and in particular to a stator core structure, stator assembly, axial flux motor, and robot. Background Technology

[0002] In existing technologies, the stator core of axial flux motors typically comes in two forms. One is an integrated stator structure, where the teeth are connected as a single unit by the stator yoke. Due to the presence of the stator yoke, this type of stator occupies a large axial dimension, making it difficult to meet the axial size requirements of motors in space-constrained applications such as the finger joints of dexterous hands in humanoid robots. Furthermore, the yoke occupies part of the axial space of the core, correspondingly reducing the height available for winding the teeth, resulting in a smaller amount of copper wire that can be wound, thus limiting the motor's output performance.

[0003] Another type is the stator segmented structure, which eliminates the stator yoke. Each tooth is independent and wound separately, allowing for the winding of more copper wire, which is beneficial for improving motor performance. However, there is no connection between the teeth, requiring a separate fixing structure to position and hold each segmented tooth in a predetermined circumferential position. This results in a complex stator structure, an increased number of parts, and cumbersome assembly procedures. The fixing structure itself also occupies radial and axial space, increasing the overall size of the stator, and is also unsuitable for the finger joints of dexterous hands.

[0004] While the two stator structures described above are adequate for conventional applications, in applications such as the finger joints of dexterous hands, the limited space within the joint restricts the size of the stator's slot system. For ease of assembly, the number of stator slots is typically limited to 9, 6, or 3. This smaller number of slots results in a smaller least common multiple between the number of stator slots and the number of rotor poles, leading to higher cogging torque, noticeable torque fluctuations during operation, and unstable output torque. This makes it difficult to meet the requirements of smooth and precise operation for the finger joints of dexterous hands. Summary of the Invention

[0005] The purpose of this invention is to provide a stator core structure, a stator assembly, an axial flux motor, and a robot to solve the technical problems of excessively large axial dimensions or complex assembly structures in the prior art.

[0006] To solve the above-mentioned technical problems, the present invention provides a stator core structure for an axial flux motor, comprising: Multiple teeth are arranged at intervals along the circumference, and each tooth has a first end and a second end opposite to each other along the axial direction; The first toothed shoe ring is an annular component, disposed at the first end of the plurality of teeth and connected to each of the teeth; The second toothed shoe ring is an annular component, disposed at the second end of the plurality of teeth and connected to each of the teeth; The first toothed shoe ring and the second toothed shoe ring connect the plurality of teeth into one unit; at least one of the first toothed shoe ring and the second toothed shoe ring is an independent component separately provided from the teeth and is fixedly connected to the teeth. Both the first toothed shoe ring and the second toothed shoe ring are provided with leakage-reducing magnetic grooves located between two adjacent teeth. The leakage-reducing magnetic grooves extend radially, and the first toothed shoe ring and the second toothed shoe ring retain connecting portions at the leakage-reducing magnetic grooves that connect the two adjacent teeth.

[0007] Optionally, the first toothed shoe ring is an integral structure with the plurality of teeth, and the second toothed shoe ring is an independent component separately disposed from the teeth and fixedly connected to the second end of the teeth; Alternatively, the first toothed shoe ring and the second toothed shoe ring are independent components separately provided from the toothed portion, and are respectively fixedly connected to the first end and the second end of the toothed portion.

[0008] Optionally, the toothed shoe ring and the toothed portion are separately provided with a groove and a protrusion, respectively, and the protrusion is embedded in the groove and cooperates with the groove.

[0009] Optionally, the leakage reduction magnetic groove extends radially through the inner and outer peripheries of the toothed shoe ring, the depth of the leakage reduction magnetic groove is less than the axial thickness of the toothed shoe ring, and the connecting part is formed by the portion between the bottom of the leakage reduction magnetic groove and the opposite surface of the toothed shoe ring.

[0010] Optionally, the central angle corresponding to the leakage reduction magnetic groove is 10% to 20% of the tooth pitch angle, and the tooth pitch angle is the ratio of 360° to the number of teeth; The depth of the leakage-reducing magnetic groove is 1 / 4 to 1 / 3 of the axial thickness of the toothed shoe ring.

[0011] Optionally, the leakage reduction magnetic groove is filled with a non-magnetic material; The non-magnetic material is at least one of epoxy potting compound, silicone rubber, and thermosetting resin.

[0012] Optionally, the first toothed shoe ring and / or the second toothed shoe ring may further provide two radially extending auxiliary grooves in the region corresponding to each tooth, the two auxiliary grooves being symmetrically arranged about the circumferential center line of the tooth.

[0013] Optionally, the central angle corresponding to each of the auxiliary grooves is 10% to 20% of the tooth pitch angle, where the tooth pitch angle is the ratio of 360° to the number of teeth; The depth of the auxiliary groove is 0.3 to 0.5 times the axial thickness of the toothed shoe ring.

[0014] Optionally, the outer periphery of the toothed shoe ring, which is separately disposed from the toothed part, is provided with an extension section for cooperating with the motor housing to fix the stator core structure.

[0015] The present invention also provides an axial flux motor stator assembly, including the stator core structure described above, and coil windings respectively wound on each of the teeth.

[0016] The present invention also provides an axial flux motor, including a housing, the aforementioned axial flux motor stator assembly, and two rotors located on both sides of the stator assembly along the axial direction, wherein the stator assembly is fixedly connected to the housing.

[0017] The present invention also provides a robot including a dexterous hand, wherein the axial flux motor described above is provided in the finger joints of the dexterous hand.

[0018] Compared with the prior art, the present invention has at least the following technical effects: In the axial flux motor stator core structure provided by this invention, at least one of the first toothed shoe ring and the second toothed shoe ring is an independent component separately disposed from the tooth portion. Before assembling the independent component, the corresponding ends of the tooth portion are exposed, and the coil can be directly wound on the tooth portion and run directly without needing to wind each tooth separately and then connect them one by one, or to make the stator into a segmented form and set up a separate fixing structure for this purpose. After assembly, the first toothed shoe ring and the second toothed shoe ring connect the multiple tooth portions into a whole, making the entire stator core a whole, reducing the assembly difficulty; at the same time, since both the first toothed shoe ring and the second toothed shoe ring are provided with There is a leakage-reducing magnetic groove located between two adjacent teeth. The magnetic circuit between adjacent teeth is blocked by the leakage-reducing magnetic groove at both tooth shoe rings, thereby reducing the leakage magnetic field between each tooth. The first tooth shoe ring and the second tooth shoe ring retain the connecting part connecting the two adjacent teeth at the leakage-reducing magnetic groove, so that the two tooth shoe rings remain mechanically complete ring parts. Thus, magnetic isolation between each tooth is achieved without sacrificing structural integrity. This balances the assembly convenience of an integrated stator with the electromagnetic performance of a segmented stator. The cogging torque and torque fluctuation of the motor are reduced accordingly, which can meet the needs of smooth and precise operation of dexterous finger joints.

[0019] Furthermore, when the first toothed shoe ring and the plurality of teeth are an integral structure, the number of parts in the stator core structure is reduced, and no separate positioning is required on one side of the integral structure, resulting in higher assembly efficiency. The cooperation between the protrusion and the groove can achieve circumferential positioning of the toothed shoe ring and the teeth during assembly, avoiding assembly deviations from affecting the symmetry of the air gap magnetic field. When the leakage-reducing magnetic groove extends radially through the inner and outer peripheries of the toothed shoe ring, the radial leakage magnetic path between adjacent teeth is completely blocked, resulting in a more sufficient magnetic isolation effect. Limiting the depth of the leakage-reducing magnetic groove to 1 / 4 to 1 / 3 of the axial thickness of the toothed shoe ring achieves a balance between excessive leakage due to shallow depth and insufficient strength of the connection due to excessive depth. When the leakage-reducing magnetic groove is filled with non-magnetic material, the filling material is equivalent to air on the magnetic circuit without changing the magnetic isolation effect, and mechanically restores the continuity of the toothed shoe ring at the leakage-reducing magnetic groove, thus allowing for a greater groove depth without reducing the structural strength of the toothed shoe ring. After the auxiliary slots are set, the air gap surface corresponding to each tooth is divided into multiple regions, which is equivalent to dividing one tooth into multiple virtual teeth. The number of virtual slots in the stator core structure increases, and the least common multiple of the number of virtual slots and the number of rotor magnetic poles increases accordingly. The cogging torque decreases as the least common multiple increases, so the cogging torque and running fluctuation of the motor can be further reduced. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the stator core structure in an embodiment of the present invention; Figure 2 This is a schematic diagram showing the positions of the coil winding and the first toothed shoe ring in an embodiment of the present invention; Figure 3 This is a diagram showing the connection relationship between the toothed part and the toothed shoe ring in an embodiment of the present invention; Figure 4 This is a schematic diagram showing the location of the leakage reduction magnetic groove in an embodiment of the present invention; Figure 5 This is a schematic diagram of the leakage magnetic circuit and the effective magnetic circuit in an embodiment of the present invention; Figure 6 This is a schematic diagram showing the location of the auxiliary slot in an embodiment of the present invention; Figure 7 This is a schematic diagram of the extension section in an embodiment of the present invention; Figure 8 This is a schematic diagram of the axial flux motor structure in an embodiment of the present invention.

[0021] 1. Tooth section; 2. First tooth shoe ring; 3. Second tooth shoe ring; 4. Integrated tooth shoe tooth section; 5. Coil winding; 6. Extension section; 7. Leakage reduction groove; 8. Leakage magnetic circuit; 9. Effective magnetic circuit; 10. Protrusion; 11. Auxiliary groove; 12. Large area; 13. Small area; 14. Housing; 15. Rotor; 16. Encoder magnetic ring; 17. Encoder PCB; 18. Groove; 19. Connecting part. Detailed Implementation

[0022] The following description, with reference to schematic diagrams, illustrates a stator core structure, stator assembly, axial flux motor, and robot according to the present invention. Preferred embodiments of the invention are shown. It should be understood that those skilled in the art can modify the invention described herein while still achieving its advantageous effects. Therefore, the following description should be understood as being of general knowledge to those skilled in the art and is not intended to limit the invention.

[0023] Based on the teachings of this specification, those skilled in the art can form new technical solutions by combining different implementation methods without creating technical contradictions. Such variations should be considered to fall within the protection scope of this application.

[0024] The invention is described more specifically by way of example in the following paragraphs with reference to the accompanying drawings. The advantages and features of the invention will become clearer from the following description. It should be noted that the drawings are in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of the invention.

[0025] It should be noted that, in the description of this application, the term "axial" refers to the direction in which the central axis of the stator core structure extends, "circumferential" refers to the direction around the central axis, and "radial" refers to the direction perpendicular to and passing through the central axis; the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0026] The axial flux motor stator core structure provided in this embodiment of the invention can be applied to axial flux motors for the finger joints of dexterous hands of humanoid robots, and can also be applied to other occasions where axial dimensions and torque stability are required.

[0027] Example 1 This embodiment provides a stator core structure for an axial flux motor, such as... Figures 1-2 As shown, the stator core structure of the axial flux motor includes multiple teeth 1, a first toothed shoe ring 2, and a second toothed shoe ring 3.

[0028] The plurality of teeth 1 are arranged circumferentially at intervals, and each tooth 1 has a first end and a second end opposite to each other along the axial direction. A winding space for accommodating the coil winding 5 is formed between two adjacent teeth 1. In a specific example, the number of teeth 1 is 9, and the 9 teeth 1 are evenly spaced circumferentially. Each tooth 1 is in the shape of a column extending along the axial direction, and its cross-section can be fan-shaped, trapezoidal, or rectangular. The number of teeth 1 can also be selected as 6, 12, or other values ​​according to the pole slot fit of the motor, and this application does not limit this.

[0029] The first toothed shoe ring 2 is an annular component, disposed at the first end of the plurality of teeth 1 and connected to each of the teeth 1; the second toothed shoe ring 3 is an annular component, disposed at the second end of the plurality of teeth 1 and connected to each of the teeth 1. The first toothed shoe ring 2 and the second toothed shoe ring 3 extend continuously in the circumferential direction and span all the teeth 1, thereby connecting the plurality of teeth 1 into a whole, so that the stator core structure is a complete component before assembly, without the need for a separate fixing structure for each stator segment as in a segmented stator. The surfaces of the first toothed shoe ring 2 and the second toothed shoe ring 3 facing away from the teeth 1 are respectively used to face the two rotors 15 of the motor. They function as toothed shoes in the motor, i.e., to adjust the air gap magnetic flux distribution, and do not function as stator yokes. Therefore, the stator core structure does not need to reserve thickness for the yoke in the axial direction.

[0030] At least one of the first toothed shoe ring 2 and the second toothed shoe ring 3 is an independent component separate from the toothed portion 1 and is fixedly connected to the toothed portion 1. Since at least one toothed shoe ring is an independent component, the corresponding end of the toothed portion 1 is exposed before the toothed shoe ring is assembled. The coil winding 5 can be directly wound on the toothed portion 1 without being obstructed by the toothed shoe during winding. The winding nozzle can directly enter the winding space along the axial direction, and the wiring between the coils on each tooth can also be completed in one go in this open state. After the winding is completed, the independent toothed shoe ring is assembled into place to obtain an integrated stator core structure.

[0031] In this embodiment, by setting at least one of the first toothed shoe ring 2 and the second toothed shoe ring 3 as an independent component separate from the toothed portion 1, the toothed portion 1 is exposed during the winding stage, and the coil can be directly wound on the toothed portion 1 and run directly. This solves the problems of the winding nozzle not being able to enter and the difficulty of connecting the windings on each tooth when the toothed shoe and the toothed portion 1 are integrated. At the same time, since there is no need to reserve space for the winding nozzle, the winding space can be utilized more fully, and more turns of copper wire can be wound in the same volume, reducing the difficulty of the winding process. In addition, by setting the first toothed shoe ring 2 and the second toothed shoe ring 3 continuously in the circumferential direction to connect the multiple toothed portions 1 into one, the stator core structure becomes a single component, overcoming the problems of the segmented stator requiring a separate fixed structure, complex structure and increased size. During assembly, it can be simply pressed into the housing 14 as a whole, significantly reducing the assembly difficulty.

[0032] In a specific example, please refer to [link / reference]. Figure 1 The first toothed shoe ring 2 and the plurality of teeth 1 form an integral toothed shoe ring 4, while the second toothed shoe ring 3 is a separate component from the teeth 1 and is fixedly connected to the second end of the teeth 1. In other words, the stator core consists of two parts: one is an integral component including the first toothed shoe ring 2 and all the teeth 1 protruding axially from one side, and the other is a separate second toothed shoe ring 3. This form has the fewest parts, there is no assembly interface between the first toothed shoe ring 2 and the teeth 1, the magnetic circuit continuity and structural strength are both good, and the integral component can be formed in one piece, simplifying the mold process and ensuring coaxiality. Therefore, it is a superior implementation.

[0033] In another specific example, the first toothed shoe ring 2 and the second toothed shoe ring 3 are both independent components separate from the toothed portion 1, and are fixedly connected to the first and second ends of the toothed portion 1, respectively. In this case, the toothed portion 1 is a central exposed column structure with both axial ends open. The coil winding 5 can be axially fitted into the toothed portion 1 from either end. Therefore, it can be wound in situ on the toothed portion 1, or pre-wound on a winding mold and then fitted, making automated winding easier. After winding, the first toothed shoe ring 2 and the second toothed shoe ring 3 are assembled onto the toothed portion 1 from both ends, thus obtaining an integrated stator core structure. In this configuration, the multiple toothed portions 1 can initially maintain their circumferential position through a support ring or tooling. After assembly, the two toothed shoe rings jointly maintain the relative positions of each toothed portion 1.

[0034] Please refer to Figure 3In the toothed shoe ring and the toothed portion 1, which are separately provided, one has a protrusion 10 and the other has a groove 18. The protrusion 10 is embedded in and cooperates with the groove 18 to achieve circumferential positioning and axial fixation of the toothed shoe ring and the toothed portion 1. In one specific example, the protrusion 10 is provided at the end of the toothed portion 1 and protrudes axially, and the groove 18 is correspondingly provided on the surface of the toothed shoe ring facing the toothed portion 1; in another specific example, the protrusion 10 may also be provided on the toothed shoe ring and the groove 18 may be provided at the end of the toothed portion 1, and their positions can be interchanged.

[0035] Furthermore, the protrusion 10 and the groove 18 can be an interference fit, relying on the interference during pressing to achieve fixation; an adhesive layer can also be provided between the protrusion 10 and the groove 18, for example, after applying structural adhesive and pressing and curing; or interference fit and adhesive fixation can be used simultaneously to further improve the reliability of the connection.

[0036] In a specific example, the protrusion 10 and the groove 18 have a dovetail-shaped structure or a stepped structure, so that the toothed shoe ring and the toothed portion 1 are axially locked together. During use, the dexterous hand finger joints are subjected to vibration and impact loads over a long period. With the above-mentioned geometric interlocking form, even if the adhesive layer ages and fails due to long-term use, the protrusion 10 will still be axially constrained by the groove 18, thereby preventing the toothed shoe ring from axially detaching from the toothed portion 1, resulting in better long-term reliability of the connection. The cross-sectional shape of the protrusion 10 and the groove 18 can also be rectangular, T-shaped, circular, or cross-shaped, etc., which can be selected by those skilled in the art according to the molding process and load-bearing requirements, and all are within the protection scope of this application.

[0037] Further, please refer to Figure 2 and Figure 4 Both the first toothed shoe ring 2 and the second toothed shoe ring 3 are provided with leakage-reducing magnetic grooves 7 located between two adjacent teeth 1. The leakage-reducing magnetic grooves 7 extend radially, and the first toothed shoe ring 2 and the second toothed shoe ring 3 retain connecting portions 19 at the leakage-reducing magnetic grooves 7 to connect the two adjacent teeth 1.

[0038] Please refer to Figure 5The effective magnetic circuit 9 of the motor is as follows: the main magnetic flux starts from the permanent magnet of the rotor 15 on one side, passes through the first toothed shoe ring 2, the tooth 1 and the second toothed shoe ring 3 along the axial direction and enters the rotor 15 on the other side. After reaching the adjacent magnetic pole through the rotor core on that side, it returns along the axial direction by passing through the adjacent tooth 1 and closing through the rotor core on the initial side. The magnetic flux on this path passes through the air gap twice and links with the coil winding 5, which is the magnetic flux that generates torque in the motor. The leakage magnetic circuit 8 is: a part of the magnetic flux does not close along the effective magnetic circuit 9, but is formed by a short circuit between two adjacent toothed shoes 1 through the first toothed shoe ring 2 or the second toothed shoe ring 3. This part of the magnetic flux does not pass through the air gap and does not link with the rotor 15, so it does not participate in the generation of torque. Instead, it occupies the magnetic flux carrying capacity of the stator core and distorts the magnetic flux density of the air gap.

[0039] The connecting portion 19, on the one hand, ensures that the toothed shoe ring remains mechanically continuous at the leakage-reducing magnetic groove 7, thereby maintaining the function of the toothed shoe ring connecting all the teeth 1 as a whole; on the other hand, since the cross-section of the connecting portion 19 is much smaller than the complete cross-section of the toothed shoe ring, the connecting portion 19 quickly reaches magnetic saturation during motor operation, and its permeability decreases significantly. Consequently, the magnetic resistance of the leakage magnetic path 8 increases substantially, and the magnetic flux is forced to flow along the effective magnetic path 9, making the magnetic paths of each tooth 1 independent again. Thus, the leakage-reducing magnetic groove 7, in cooperation with the connecting portion 19, keeps the toothed shoe ring mechanically continuous but is broken in the magnetic path, suppressing magnetic leakage between adjacent teeth 1 while maintaining the stator's integration.

[0040] The number of leakage-reducing magnetic grooves 7 corresponds to the number of intervals between adjacent teeth 1. When there are 9 teeth 1, each tooth shoe ring is provided with 9 leakage-reducing magnetic grooves 7, which are evenly distributed along the circumference.

[0041] In one specific example, the number of leakage-reducing magnetic grooves 7 on the first toothed shoe ring 2 and the number of leakage-reducing magnetic grooves 7 on the second toothed shoe ring 3 are the same and correspond one-to-one. The axial projections of the corresponding two leakage-reducing magnetic grooves 7 coincide, that is, the slots on the two toothed shoe rings are aligned in the circumferential direction. This allows the leakage magnetic paths 8 on both sides of the gap between adjacent teeth 1 to be blocked simultaneously, resulting in a more balanced magnetic isolation effect and facilitating the assembly and positioning of the second toothed shoe ring 3. In another specific example, the leakage-reducing magnetic grooves 7 on the two toothed shoe rings can also be staggered in the circumferential direction. The staggered angle can be 1 / 4 to 1 / 2 of the tooth pitch angle. The staggered arrangement helps to further smooth the change of air gap magnetic permeability in the circumferential direction, thereby suppressing some harmonic components in the tooth cogging torque.

[0042] In this embodiment, by providing the leakage-reducing magnetic groove 7 on both of the toothed shoe rings and retaining the connecting part 19, the toothed shoe rings are mechanically continuous but magnetically broken, thereby obtaining an integrated structure while avoiding magnetic leakage between adjacent teeth 1. This combines the advantages of easy assembly of an integrated stator and independent magnetic circuit of a segmented stator. Furthermore, since the toothed shoe ring itself acts as a toothed shoe to adjust the air gap magnetic flux density distribution, the cogging torque and running fluctuation of the motor are reduced, which can meet the needs of smooth and precise operation of the finger joints of a dexterous hand.

[0043] In a specific example, the leakage-reducing magnetic groove 7 extends radially through the inner and outer peripheries of the toothed shoe ring. The depth of the leakage-reducing magnetic groove 7 is less than the axial thickness of the toothed shoe ring. The connecting portion 19 is formed by the portion between the bottom of the leakage-reducing magnetic groove 7 and the opposing surface of the toothed shoe ring. At this time, the leakage-reducing magnetic groove 7 is completely disconnected radially, and there is no bypass magnetic path between adjacent teeth 1 on the radially inner and outer sides. The leakage magnetic field can only pass through the thin layer of material remaining at the bottom of the groove, and this thin layer of material is in a magnetically saturated state during operation, resulting in good magnetic isolation. At the same time, the connecting portion 19 extends along the entire radial width, with a large load-bearing area, thus maintaining the overall rigidity of the toothed shoe ring.

[0044] In another specific example, the leakage-reducing magnetic groove 7 penetrates the toothed shoe ring axially, and the connecting portion 19 is located radially inner and / or radially outer of the leakage-reducing magnetic groove 7. That is, the leakage-reducing magnetic groove 7 completely cuts through the toothed shoe ring axially, but does not extend radially to the inner and outer circumferences of the toothed shoe ring, thus retaining a narrow connecting rib at each radial end of the leakage-reducing magnetic groove 7 as the connecting portion 19. In this form, the magnetic isolation position is shifted from the bottom of the groove to the connecting ribs at both radial ends. The leakage magnetic field is blocked by the magnetic saturation of these connecting ribs. The advantage is that the axial isolation of the leakage-reducing magnetic groove 7 is more thorough, making it suitable for situations where the axial thickness of the toothed shoe ring is small and it is difficult to further layer and groove in the thickness direction.

[0045] Furthermore, the central angle corresponding to the leakage-reducing magnetic groove 7 is 10% to 20% of the tooth pitch angle, and the tooth pitch angle is the ratio of 360° to the number of teeth 1. In a specific example where the number of teeth 1 is 9, the tooth pitch angle is 360° / 9 = 40°, and the central angle corresponding to the leakage-reducing magnetic groove 7 is correspondingly taken as 4° to 8°, for example, 15% of the tooth pitch angle, i.e., 40° × 0.15 = 6°. If the central angle is too small, the distance between the two side walls of the leakage-reducing magnetic groove 7 is insufficient, and there are still many magnetic lines of force crossing the leakage-reducing magnetic groove 7 between adjacent teeth 1, resulting in leakage magnetic flux; if the central angle is too large, the effective tooth shoe area on the tooth shoe ring is reduced, the fundamental amplitude of the air gap magnetic flux density decreases, and the output torque of the motor decreases accordingly.

[0046] When the leakage-reducing magnetic groove 7 extends radially but does not axially penetrate the toothed shoe ring, the depth of the leakage-reducing magnetic groove 7 is 1 / 4 to 1 / 3 of the axial thickness of the toothed shoe ring. If the depth is too shallow, the cross-section of the connecting part 19 is too large and it is not easy to enter magnetic saturation, resulting in insufficient leakage magnetic suppression effect; if the depth is too deep, the cross-section of the connecting part 19 is too small. Since the connecting part 19 is located between two adjacent teeth 1, it is the only load-bearing section of the toothed shoe ring that transmits assembly pressing force and electromagnetic force during operation. If the cross-section is too small, the structural strength of the toothed shoe ring will be insufficient, and there is a risk of cracking during pressing or impact.

[0047] In a specific example, the leakage-reducing magnetic groove 7 is filled with a non-magnetic material, which is at least one of epoxy potting compound, silicone, and thermosetting resin. The relative permeability of the non-magnetic material is close to 1, and it is equivalent to air in the magnetic circuit, thus not weakening the magnetic isolation effect of the leakage-reducing magnetic groove 7. Mechanically, after the non-magnetic material cures, it re-bonds the toothed shoe portions on both sides of the leakage-reducing magnetic groove 7 into a continuous whole, restoring the mechanical continuity of the toothed shoe ring at the slot. Therefore, the depth of the leakage-reducing magnetic groove 7 is no longer simply limited by the load-bearing capacity of the connecting part 19, and a greater depth can be taken while maintaining structural strength, for example, more than 1 / 3 of the axial thickness of the toothed shoe ring, so that the cross-section of the connecting part 19 is further reduced, the magnetic saturation is more sufficient, and the magnetic isolation effect is improved. The non-magnetic material can also be combined with the bonding process at the protrusion 10 and the groove 18 during the assembly of the toothed shoe ring. That is, it can be injected and cured in one go after pressing, serving the dual purpose of filling the leakage-reducing magnetic groove 7 and bonding and fixing the toothed shoe ring without adding any extra steps. The non-magnetic material can also be other insulating adhesives or engineering plastics without magnetic fillers, and can be filled into the leakage-reducing magnetic groove 7 by means of potting, dispensing or injection molding embedding. These are all common methods used by those skilled in the art and will not be described in detail here.

[0048] For further details, please refer to... Figure 6 The first toothed shoe ring 2 and / or the second toothed shoe ring 3 are further provided with two radially extending auxiliary grooves 11 in the region corresponding to each tooth 1. The two auxiliary grooves 11 are symmetrically arranged about the circumferential center line of the tooth 1. The circumferential center line is the position of the straight line that passes through the central axis of the stator core structure and bisects the tooth circumferentially. The auxiliary grooves 11 are recessed from the surface of the toothed shoe ring away from the tooth 1 and penetrate radially through the inner and outer circumferences of the toothed shoe ring.

[0049] The two auxiliary slots 11 divide the air gap surface corresponding to the tooth 1 into three regions circumferentially. The region between the two auxiliary slots 11 is a large region 12, and the two smaller regions between the auxiliary slots 11 and the leakage-reducing magnetic slot 7 are two smaller regions 13. This creates three virtual teeth for each tooth 1 on the air gap side. The cogging torque of the motor is related to the least common multiple of the number of slots and poles, N = LCM(Q, 2P). The larger N is, the smaller the cogging torque and the smaller the operating fluctuation. In a specific example where the number of teeth 1 is 9 and the number of magnetic poles of the rotor 15 is 12, the pole-slot combination before setting the auxiliary slots 11 is 9 slots and 12 poles, with a least common multiple of 36. After setting the auxiliary slots 11, the equivalent number of virtual slots changes from 9 to 27, and the pole-slot combination is equivalent to 27 slots and 12 poles. The least common multiple increases from 36 to 108, thus significantly reducing the cogging torque and torque fluctuation. The auxiliary slot 11 thus overcomes the limitation that dexterous hand finger joints can only use 9 slots, 6 slots, or 3 slots due to the small toothed system, and the toothed torque is too large, without changing the actual winding structure and winding process.

[0050] The central angle corresponding to each auxiliary slot 11 is 10% to 20% of the tooth pitch angle, which is 4° to 8° in the specific example where the tooth pitch angle is 40°. When the central angle is within this range, the air gap magnetic permeability changes of the three virtual teeth are relatively equal, and the equivalent effect of the virtual teeth is the best. If the central angle is too small, the disturbance of the air gap magnetic permeability is insufficient, and the virtual tooth effect is not obvious. If the central angle is too large, the effective tooth shoe area is lost too much, and the output torque decreases.

[0051] The depth of the auxiliary groove 11 is 0.3 to 0.5 times the axial thickness of the toothed shoe ring. Within this depth range, the air gap magnetic permeability at the auxiliary groove 11 is sufficiently reduced to form a virtual tooth, without excessively weakening the main magnetic flux passing through it, thus preventing a significant reduction in output torque. It should be noted that the depth of the auxiliary groove 11 can be greater than the depth of the leakage-reducing magnetic groove 7. This is because the leakage-reducing magnetic groove 7 is located between two adjacent tooth portions 1, which is the only load-bearing section of the toothed shoe ring connecting adjacent toothed shoes and transmitting assembly pressing force and electromagnetic force; its depth is constrained by structural strength. The auxiliary groove 11, however, is located within the area corresponding to the tooth portion 1, with the tooth portion 1 directly supporting the toothed shoe at that location. Therefore, opening the auxiliary groove 11 does not weaken the circumferential load-bearing path of the toothed shoe ring, allowing for a greater depth to fully modulate the air gap magnetic permeability.

[0052] In one specific example, the auxiliary groove 11 is provided on only one of the first toothed shoe ring 2 and the second toothed shoe ring 3; in another specific example, the auxiliary groove 11 is provided on both toothed shoe rings, and the axial projections of the auxiliary grooves 11 on the two toothed shoe rings coincide with each other. For applications with general tooth cogging torque requirements, the auxiliary groove 11 may not be provided, and the corresponding effect can be obtained solely by the leakage reduction magnetic groove 7. In addition, the number of auxiliary grooves 11 in the region corresponding to each tooth 1 can also be an even number, such as four or six, and symmetrically arranged about the circumferential center line of the tooth 1. In this case, each tooth 1 forms five or seven virtual teeth, and the number of virtual grooves is further increased.

[0053] For further details, please refer to... Figures 7-8 An extension section 6 is provided on the outer periphery of the toothed shoe ring, which is separately arranged from the toothed part 1. The extension section 6 is used to cooperate with the motor housing 14 to fix the stator core structure. The extension section 6 extends axially and can be a continuous annular flange or multiple bosses distributed circumferentially. During assembly, the outer peripheral surface of the extension section 6 mates with the inner wall surface of the housing 14. The two can be fixed by interference fit, bonding, or by setting buckles, pins, etc., so that the entire stator core structure and even the stator assembly are fixed in the housing 14 axially and circumferentially through the extension section 6, without the need to set separate fixing structures for each toothed part 1. The extension section 6 also plays an axial limiting role in the housing 14, determining the axial position of the stator relative to the two rotors 15 on both sides, thereby ensuring the consistency of the air gap on both sides.

[0054] The materials for the tooth portion 1, the first toothed shoe ring 2, and the second toothed shoe ring 3 can be sintered from a mixture of soft magnetic composite material and adhesive, or from a mixture of amorphous alloy material and adhesive. These materials have low iron loss, which helps reduce high-frequency losses in the motor. Furthermore, they can be molded into various irregular structures through molding and sintering, facilitating the formation of the integral structure of the tooth portion 1 and the first toothed shoe ring 2, the protrusion 10 and the groove 18, the leakage-reducing magnetic groove 7, and the auxiliary groove 11, etc. Generally, no further machining is required after forming. The specific grade of the material, the particle size distribution, and the selection of sintering process parameters are common practices for those skilled in the art and will not be elaborated further.

[0055] In summary, the axial flux motor stator core structure described in this embodiment solves the problems of direct winding and connection difficulties when the toothed part 1 is integrated with the toothed part 1 by setting at least one of the first toothed shoe ring 2 and the second toothed shoe ring 3 as an independent component separate from the toothed part 1. This allows the toothed part 1 to remain exposed during the winding stage, enabling the coil winding 5 to be directly wound and routed. It also makes fuller use of the winding space, allowing for the winding of more copper wire. By setting two circumferentially continuous toothed shoe rings to connect the multiple toothed parts 1 into a single unit, the stator core becomes a single component, eliminating the need for separate fixing structures for each stator segment as required by a segmented stator. During assembly, the entire unit can be pressed into the housing 14, and no sub-yoke is required. The axial dimension is small; by setting the leakage-reducing magnetic groove 7 on both of the toothed shoe rings and retaining the connecting part 19, the toothed shoe rings are mechanically continuous but magnetically broken. While obtaining an integrated structure, the leakage magnetic flux between adjacent toothed parts 1 is blocked. It has the dual advantages of easy assembly of integrated stator and independent magnetic circuit of segmented stator. On this basis, the non-magnetic material filling in the leakage-reducing magnetic groove 7 makes the groove depth no longer limited by the load-bearing capacity of the connecting part 19. The auxiliary groove 11 makes each toothed part 1 form multiple virtual teeth and increases the least common multiple of pole slots. Together, they further reduce the cogging torque and torque fluctuation of the motor, thereby meeting the needs of dexterous hand finger joints to operate smoothly and precisely in a narrow space.

[0056] Example 2 This invention provides an axial flux motor stator assembly, including the axial flux motor stator core structure described in the above embodiments, and coil windings 5 ​​respectively wound on each of the tooth portions 1.

[0057] The coil winding 5 is made of copper wire, and the outer surface of the copper wire is coated with insulating varnish. In one specific example, the coil winding 5 is formed by winding self-adhesive enameled wire onto the toothed portion 1 and then heating and curing it. That is, the self-adhesive enameled wire is directly wound onto the toothed portion 1, and after winding, it is heated to melt the self-adhesive layer on the surface of the enameled wire. After cooling, the coil turns are bonded together as a whole, thereby fixing the coil winding 5 onto the toothed portion 1. It will not loosen or shift during subsequent assembly of the toothed shoe ring and during motor operation, eliminating the need for a separate winding frame or binding structure, which helps to reduce space occupation and improve slot fill factor. In another specific example, the coil winding 5 can also be pre-formed on a winding mold and then fitted onto the toothed portion 1.

[0058] In one specific example, an insulating layer is provided between the surface of the tooth 1 and the coil winding 5. The insulating layer may be insulating adhesive or insulating varnish coated on the surface of the tooth 1, or it may be an insulating film or insulating skeleton covering the surface of the tooth 1, used to prevent short circuits between the coil winding 5 and the stator core. The insulating layer may also extend to cover the surfaces of the first toothed shoe ring 2 and the second toothed shoe ring 3 facing the coil winding 5.

[0059] The assembly process of the stator assembly may include the following steps: S1. Provide the stator core, the stator core including a plurality of teeth 1 arranged at intervals along the circumference, and a first toothed shoe ring 2 integrally formed with the teeth 1; the insulating layer is provided on the surface of the teeth 1; S2. The self-adhesive enameled wire is wound sequentially on each of the teeth 1 to form the coil winding 5, and the wiring between each of the coil windings 5 ​​is completed. Then the coil winding 5 is heated to solidify it and fix it on the teeth 1. S3. Press the second toothed shoe ring 3 into place axially from the second end of the toothed portion 1, so that the protrusion 10 at the end of the toothed portion 1 is embedded in the groove 18 of the second toothed shoe ring 3 to achieve fixation, so that the stator assembly becomes a whole. S4. The non-magnetic material is poured into the leakage-reducing magnetic groove 7 of the first toothed shoe ring 2 and the second toothed shoe ring 3 and then cured.

[0060] It should be noted that when the first toothed shoe ring 2 and the second toothed shoe ring 3 are both independent components, the stator core provided in step S1 is a toothed portion 1 assembly without the toothed shoe rings, and in step S3, the two toothed shoe rings are pressed into place from both ends of the toothed portion 1. Step S4 is an optional step and can be omitted when the leakage reduction magnetic groove 7 contains an air gap.

[0061] This invention also provides an axial flux motor; please refer to further details. Figure 8The motor includes a housing 14, the aforementioned axial flux motor stator assembly, and two rotors 15 located on opposite axial sides of the stator assembly. The stator assembly is fixedly connected to the housing 14. The stator assembly is fixed within the housing 14 via the extension section 6. The two rotors 15 are located on opposite axial sides of the stator assembly and form an air gap between the first toothed shoe ring 2 and the second toothed shoe ring 3. Each rotor 15 has permanent magnets; in one specific example, the rotor 15 has 12 magnetic poles. The motor may also include an end cover, an encoder magnetic ring 16, and an encoder PCB 17. The end cover is connected to the housing 14. The encoder magnetic ring 16 rotates with the rotor 15 or the shaft. The encoder PCB 17 is positioned opposite the encoder magnetic ring 16 to detect the position of the rotor 15. The specific structure of the rotor 15, the arrangement of the bearings, and the selection and installation method of the encoder are all common practices for those skilled in the art and will not be described in detail here.

[0062] This invention also provides a robot, including a dexterous hand, in which the aforementioned axial flux motor is installed within the finger joints. Because the stator core structure eliminates the stator yoke and does not require a fixing structure for the segmented stator, the axial and radial dimensions of the motor are both small, allowing it to fit within the confined space of the dexterous hand's finger joints. Simultaneously, the motor exhibits low cogging torque and torque fluctuation, resulting in smoother operation of the finger joints at low speeds and with minute displacement control, which facilitates the dexterous hand in performing fine operations. The robot may also include components such as a torso and a robotic arm; their specific structures will not be described in detail.

[0063] In summary, this invention solves the problems of direct winding and difficulty in connecting windings on individual teeth when the tooth shoe and the tooth are integrated. By setting at least one of the first and second tooth shoe rings as independent components separate from the tooth portion, the tooth portion is exposed during the winding stage, allowing the coil winding to be directly wound onto the tooth portion and routed directly. This also makes fuller use of the winding space, allowing more copper wire to be wound within the same volume, improving motor performance and reducing the difficulty of the winding process. Furthermore, by setting the first and second tooth shoe rings, which are continuous circumferentially, to connect the multiple teeth into a single unit, the stator becomes a single component. This overcomes the problems of segmented stators requiring separate fixing structures, resulting in complex structures and increased dimensions. Assembly can be completed simply by pressing the entire unit into the housing, significantly reducing assembly difficulty. Furthermore, the stator core structure does not have a yoke, resulting in a small axial dimension, making it suitable for space-constrained applications such as the finger joints of dexterous hands. By setting the leakage-reducing magnetic groove and retaining the connecting part at the leakage-reducing magnetic groove, the toothed shoe ring remains mechanically continuous but is broken in the magnetic circuit. This achieves an integrated structure while avoiding magnetic leakage between adjacent teeth via the toothed shoe ring, thus combining the advantages of easy assembly of an integrated stator and independent magnetic circuit of a segmented stator, and reducing the cogging torque and running fluctuations of the motor. By setting two auxiliary grooves, the cogging torque and torque fluctuations are further reduced without changing the actual winding structure and winding process, overcoming the limitation of large cogging torque in the finger joints of dexterous hands due to the small size of the cogging system and the limited number of grooves, and meeting the needs of smooth and precise operation of the finger joints.

[0064] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A stator core structure, characterized in that, include: Multiple teeth are arranged at intervals along the circumference, and each tooth has a first end and a second end opposite to each other along the axial direction; The first toothed shoe ring is an annular component, disposed at the first end of the plurality of teeth and connected to each of the teeth; The second toothed shoe ring is an annular component, disposed at the second end of the plurality of teeth and connected to each of the teeth; The first toothed shoe ring and the second toothed shoe ring connect the plurality of teeth into one unit; at least one of the first toothed shoe ring and the second toothed shoe ring is an independent component separately provided from the teeth and is fixedly connected to the teeth. Both the first toothed shoe ring and the second toothed shoe ring are provided with leakage-reducing magnetic grooves located between two adjacent teeth. The leakage-reducing magnetic grooves extend radially, and the first toothed shoe ring and the second toothed shoe ring retain connecting portions at the leakage-reducing magnetic grooves that connect the two adjacent teeth.

2. The stator core structure according to claim 1, characterized in that, The first toothed shoe ring is an integral structure with the plurality of teeth, and the second toothed shoe ring is an independent component separately disposed from the teeth and fixedly connected to the second end of the teeth; Alternatively, the first toothed shoe ring and the second toothed shoe ring are independent components separately provided from the toothed portion, and are respectively fixedly connected to the first end and the second end of the toothed portion.

3. The stator core structure according to claim 1, characterized in that, The toothed shoe ring and the toothed part are separately provided with grooves and protrusions, respectively, and the protrusions are embedded in the grooves and cooperate with the grooves.

4. The stator core structure according to claim 1, characterized in that, The leakage reduction magnetic groove extends radially through the inner and outer peripheries of the toothed shoe ring. The depth of the leakage reduction magnetic groove is less than the axial thickness of the toothed shoe ring. The connecting part is formed by the portion between the bottom of the leakage reduction magnetic groove and the opposite surface of the toothed shoe ring.

5. The stator core structure according to claim 4, characterized in that, The central angle corresponding to the leakage reduction magnetic groove is 10% to 20% of the tooth pitch angle, and the tooth pitch angle is the ratio of 360° to the number of teeth. The depth of the leakage-reducing magnetic groove is 1 / 4 to 1 / 3 of the axial thickness of the toothed shoe ring.

6. The stator core structure according to claim 1, characterized in that, The leakage reduction magnetic groove is filled with a non-magnetic material; The non-magnetic material is at least one of epoxy potting compound, silicone rubber, and thermosetting resin.

7. The stator core structure according to claim 1, characterized in that, The first toothed shoe ring and / or the second toothed shoe ring are further provided with two radially extending auxiliary grooves in the region corresponding to each tooth, and the two auxiliary grooves are symmetrically arranged about the circumferential center line of the tooth.

8. The stator core structure according to claim 7, characterized in that, The central angle corresponding to each of the auxiliary slots is 10% to 20% of the tooth pitch angle, and the tooth pitch angle is the ratio of 360° to the number of teeth; The depth of the auxiliary groove is 0.3 to 0.5 times the axial thickness of the toothed shoe ring.

9. The stator core structure according to claim 1, characterized in that, The outer periphery of the toothed shoe ring, which is separately provided with the toothed part, has an extension section for cooperating with the motor housing to fix the stator core structure.

10. A stator assembly for an axial flux motor, characterized in that, It includes the stator core structure according to any one of claims 1 to 9, and coil windings respectively wound on each of the teeth.

11. An axial flux motor, characterized in that, It includes a housing, an axial flux motor stator assembly as described in claim 10, and two rotors located on opposite axial sides of the stator assembly, wherein the stator assembly is fixedly connected to the housing.

12. A robot, characterized in that, The invention includes a dexterous hand, wherein the finger joints of the dexterous hand are provided with the axial flux motor of claim 11.

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