A stator based on a split tooth winding, a frameless motor and a rotating device

Abstract

This invention discloses a stator, frameless motor, and rotating device based on tooth-separated windings, comprising an alternating tooth integral iron core and tooth-separated concentrated windings. The alternating tooth integral iron core includes first stator teeth and second stator teeth arranged alternately in a circumferential pattern. The first stator teeth are parallel or near-parallel teeth; the second stator teeth are trapezoidal teeth, with a tooth tip width w3 smaller than a tooth root width w4. Parallel or near-parallel stator slots are formed between the first stator teeth and adjacent second stator teeth on both sides. The tooth-separated concentrated windings are all mounted on the first stator teeth. This invention can effectively improve the slot fill factor and fundamental winding coefficient of the motor while simplifying the process, improving mass production consistency, and reducing leakage flux. It effectively improves the performance density of the frameless motor (including torque density and power density, or achieves motor size reduction and weight reduction while meeting the same torque capacity), while also increasing the thermal conductivity of the windings and improving service life.

Description

Technical Field

[0001] This invention relates to the field of motor design and manufacturing, and in particular to a stator, frameless motor and rotating device based on tooth-separated windings. Background Technology

[0002] Since the beginning of the 21st century, the breadth and depth of global industrial development have been increasing. With various industries demanding higher standards for emissions, energy efficiency, and cutting-edge intelligent technologies, electric motors, as core energy conversion equipment, have played a crucial role. Thanks to the increased energy density of permanent magnets, permanent magnet motors possess advantages such as high torque / power density, high efficiency, and high power factor, and have been widely applied in various industries, including manufacturing, electric vehicles, robotics, and low-altitude aircraft.

[0003] New types of electric equipment, represented by robots, place higher demands on the performance density (including torque density / power density), lightweight design, and efficiency of permanent magnet motors (including frameless torque motors). For example, frameless torque motors, as core drive components of collaborative and humanoid robot joints, are directly embedded within the joint, without independent housings, bearings, or output shafts. Motor performance directly determines the joint's load, dynamics, endurance, heat generation, and overall weight ratio. The compact space of robot joints allows for motor miniaturization with high torque density, facilitating integrated joint installation. Simultaneously, it increases the robot's load-to-weight ratio, reduces rotor inertia, and improves motion response speed, adapting to the needs of direct drive and precision force control. Furthermore, lightweight motors reduce the overall weight of the robot, decreasing the drive load on each joint level and reducing ineffective power consumption. Since robot joints have poor internal heat dissipation, high-efficiency motor operation reduces heat generation, preventing motor demagnetization and component aging, thereby increasing the robot's lifespan and reliability.

[0004] Existing permanent magnet motors (including frameless torque motors) use a method of separating the teeth and yoke, such as CN223744443U and CN118232581B. A coil assembly entrance is formed between two adjacent splicing points of the teeth and yoke, which facilitates the assembly of the pre-formed coil from the outside to the inside into the slot. Although this solution can avoid the space waste caused by the winding equipment directly winding in the slot, it still has the following shortcomings: (1) Separating the teeth and yoke increases the production and assembly process; (2) The separated parts have their own processing tolerances, which will lead to error accumulation during assembly, affecting the critical dimension accuracy of the motor stator and increasing the difficulty of consistency control in mass production; (3) It is necessary to form an iron core connecting bridge at the slot opening and mechanically connect the separated teeth through the iron core connecting bridge. However, the iron core connecting bridge directly faces the air gap and will form obvious leakage flux (short-circuit flux), thereby reducing the torque density, power density and efficiency of the motor.

[0005] Therefore, how to improve the performance density (or reduce motor size and weight while maintaining the same performance), operating efficiency (reduce winding resistance and copper loss), and service life (reduce heat generation) of permanent magnet motors (including frameless torque motors) while simplifying processes, improving mass production consistency, and reducing leakage flux is of great theoretical significance and practical value for promoting the further application and development of intelligent mobile equipment such as humanoid robots. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to address the shortcomings of the prior art by providing a stator, frameless motor and rotating device based on tooth-separated windings. This stator, frameless motor and rotating device based on tooth-separated windings can effectively improve the slot fill factor and fundamental winding coefficient of the motor while simplifying the process, improving mass production consistency and reducing leakage flux. It can effectively improve the performance density (including torque density and power density) of permanent magnet motors (including frameless torque motors), or achieve motor size reduction and weight reduction while meeting the same torque capacity, improve operating efficiency (reduce winding resistance and copper loss, while increasing the thermal conductivity of the windings), and improve service life (reduce heat generation).

[0007] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0008] A stator based on tooth-separated windings includes an alternating tooth integral iron core and a tooth-separated concentrated winding.

[0009] The alternating tooth integral iron core includes first stator teeth and second stator teeth arranged alternately in a circumferential cycle.

[0010] The first stator tooth is a parallel tooth or a near-parallel tooth.

[0011] The second stator tooth is a trapezoidal tooth, and its tooth tip width w3 is smaller than its tooth root width w4.

[0012] The first stator tooth and the adjacent second stator teeth on both sides form parallel or near-parallel stator slots, respectively.

[0013] All the tooth-separated concentrated windings are assembled on the first stator tooth.

[0014] Distribution coefficient k of tooth-separated concentrated winding d =1, the potentials of all coils in the same phase winding are in phase.

[0015] The second stator tooth is provided with a weight reduction hole, through which cooling fluid can pass.

[0016] The cross-sectional area of ​​the weight reduction hole gradually increases radially from the inside to the outside, so that the effective magnetic cross-section of the second stator tooth is equal at different diameter positions.

[0017] The concentrated winding consists of Ns / 2 concentrated coils; where Ns is the number of stator slots; the number of stator slots Ns' in each unit motor satisfies the following calculation formula:

[0018] Ns'=2p'±2;

[0019] in:

[0020] Ns'=Ns / t;

[0021] p'=p / t;

[0022] In the formula, p' is the number of rotor pole pairs in each unit motor; p is the number of rotor pole pairs; and t is the number of unit motors.

[0023] Each centralized coil is a pre-formed coil with pre-reserved start and end leads; the pre-formed coil is pre-formed outside the stator slot, and then assembled from the stator slot opening to the first stator tooth. Then, the pre-reserved start and end leads of each pre-formed coil are directly or indirectly connected for electrical conduction.

[0024] In single or multiple unit motors, the concentrated coils of the same phase windings adopt series or parallel continuous windings.

[0025] The conductor used in each centralized coil can be flat, round, square, or irregularly shaped; when flat wire is used, the centralized coil is formed by vertical winding or horizontal winding.

[0026] The present invention also provides a frameless motor, including a stator based on tooth-separated windings.

[0027] The present invention also provides a rotating device, including a frameless motor.

[0028] The invention has the following beneficial effects:

[0029] 1. The stator based on the tooth-separated winding of the present invention has a first stator tooth and a second stator tooth arranged alternately in a circular pattern on the circumference. The first stator tooth, the second stator tooth, and the stator yoke are an integral iron core. Parallel slots (or quasi-parallel slots) are formed between the first stator tooth and the second stator tooth, and the first stator tooth is a parallel tooth (or quasi-parallel tooth). This invention is adapted to the concentrated coils of the present invention, whose widths are equal or approximately equal in the radial direction on the first stator tooth. Moreover, the present invention only requires assembling the pre-formed concentrated coils from the slot opening onto the first stator tooth. While improving the slot fill factor and the fundamental winding coefficient (wherein the distribution coefficient reaches 1), it overcomes the shortcomings of the tooth and yoke separation scheme, such as the connection bridge introduced by the connection bridge and the resulting leakage flux, complex process, and error accumulation affecting batch consistency. It also cleverly avoids the coil slot interference problem and the waste of slot space between adjacent coils in traditional integral iron core motors.

[0030] 2. In this invention, the stator slot has only one coil side, and the two sides and bottom of the coil have a wide contact surface with the three sides of the slot, with a short distance, which can effectively improve the coil's ability to conduct heat outward. At the same time, halving the number of coils not only helps to increase the assembly cycle and improve production efficiency, but also avoids the phenomenon of two coils squeezing or rubbing against each other that may occur when there are two coil sides in the same slot, effectively reducing the risk of insulation failure.

[0031] 3. The weight-reducing holes in this invention enable the effective magnetic cross-sections at different diameter positions of the second stator teeth to be equal or similar. This not only helps to improve the uniformity of magnetic flux on the second stator teeth, thereby increasing the overall utilization rate of the iron core, but also reduces the weight of the stator, which is beneficial for the lightweighting of the motor. In addition, they can also serve as cooling holes, providing a fluid flow path for cooling liquids or air, thereby increasing the motor's cooling capacity, reducing the motor's temperature rise, and improving the motor's service life and reliability. Attached Figure Description

[0032] Figure 1 The diagram shows a frameless motor structure of the present invention, which includes a stator based on tooth-separated windings.

[0033] Figure 2 This diagram shows a partially enlarged schematic of the parallel or near-parallel stator slots in this invention.

[0034] Figure 3 The diagram shows a schematic of a flat-wire wound centralized coil in this invention; (a) is a cross-sectional view of a 24-slot, 28-pole coil; (b) is a three-dimensional view of a 36-slot, 42-pole coil.

[0035] Figure 4 The diagram shows a schematic of a flat wire vertically wound centralized coil in this invention; (a) is a cross-sectional view of a 24-slot, 28-pole coil; (b) is a three-dimensional view of a 36-slot, 42-pole coil.

[0036] Figure 5 The diagram shows the coil potential star diagram of the centralized winding in this invention – 24 slots and 28 poles.

[0037] Figure 6 This diagram illustrates a continuous flat winding method using flat wires connected in series between the coils of the same phase winding within the unit motor of this invention.

[0038] Figure 7 The diagram shows the wiring principle when the coils of the same phase windings in the unit motor of the present invention are continuously wound in series.

[0039] Figure 8 The diagram shows the wiring principle when the coils of the same phase windings in the unit motor of the present invention are connected in parallel.

[0040] Figure 9The diagram shows the wiring principle between the in-phase windings of multiple unit motors when the present invention is star-connected; (a) corresponds to series connection; (b) corresponds to parallel connection.

[0041] Figure 10 The diagram shows the wiring principle between the in-phase windings of multiple unit motors when the present invention is used in a delta connection; (a) corresponds to series connection; (b) corresponds to parallel connection.

[0042] Figure 11 A schematic diagram of the weight reduction hole in the second stator tooth of the present invention is shown.

[0043] Figure 12 The diagram shows the torque improvement effect of the motor of the present invention; (a) torque comparison; (b) torque improvement of the present invention compared with the prior art.

[0044] Among them are:

[0045] 10. Alternating tooth integral iron core;

[0046] 11. First stator tooth; 12. Second stator tooth; 121. Weight reduction hole;

[0047] 13. Tooth-separated concentrated winding; 131. Interlayer connecting wire; 132. Continuous winding wire; 133. Flat wire flat-wound concentrated coil; 134. Flat wire vertical-wound concentrated coil; 135. Start and end leads of a single coil;

[0048] 14. Insulating components;

[0049] 20. Rotor core; 21. Permanent magnet. Detailed Implementation

[0050] The present invention will now be described in further detail with reference to the accompanying drawings and specific preferred embodiments.

[0051] In the description of this invention, it should be understood that the terms "left side," "right side," "upper part," "lower part," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention 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. "First," "second," etc., do not indicate the importance of the components, and therefore should not be construed as a limitation of this invention. The specific dimensions used in this embodiment are only for illustrating the technical solution and do not limit the scope of protection of this invention.

[0052] like Figure 1As shown, a frameless motor includes a stator based on toothed windings, a rotor, and an air gap between them; wherein the rotor is an inner rotor or an outer rotor, and in this embodiment, an inner rotor is preferred; further, the rotor can be a straight-pole structure or a segmented skew-pole structure. The rotor includes a rotor core 20 and a permanent magnet 21. The rotor core can be a solid structure, or a laminated or wound structure. When a laminated structure is used, the axial connection between the laminations can be riveted, snap-fitted, or glued. The permanent magnet can be an integral magnetic ring structure, or a tile-shaped, bread-shaped, rectangular magnet, or Halbach magnet.

[0053] The stator can be potted to enhance thermal conductivity and insulation, while also improving the overall integrity of the windings, stator stiffness, and impact resistance, depending on the actual needs of the application scenario. The potting material is not limited and can include two-component thermally conductive epoxy resin, thermally conductive silicone potting compound, polyurethane (PU) potting compound, aluminum nitride high thermal conductivity epoxy resin, etc.

[0054] A stator based on tooth-separated winding includes an alternating tooth integral iron core 10 and a tooth-separated concentrated winding.

[0055] The alternating tooth integral iron core can be a lamination stacked structure, a spiral winding structure, or a chain winding structure. When a lamination stacked structure is used, the axial connection between the laminations can be a riveted connection, a snap-fit ​​connection, or an adhesive bonding. Alternatively, the slot bottom of the alternating tooth integral iron core can be an arc-shaped slot bottom or a flat-bottomed slot, and the slot opening of the iron core can contain micro-tooth shoes.

[0056] The alternating tooth integral iron core includes a first stator tooth 11 and a second stator tooth 12 arranged alternately in the circumferential direction.

[0057] The first stator tooth is a parallel tooth or a near-parallel tooth, such as... Figure 2 As shown, its tooth tip width w1 is equal to or approximately equal to its tooth root width w2, that is, w1=w2 or w1≈w2.

[0058] The second stator tooth is a trapezoidal tooth, and its tooth tip width w3 is less than its tooth root width w4, that is, w3 < w4.

[0059] like Figure 11 As shown, a weight-reducing hole 121 is provided in the second stator tooth, through which cooling fluids such as liquid or air can flow. The weight-reducing hole enables the motor to be lighter and more compact, while also serving as a cooling hole to provide a fluid flow path for cooling liquids or air, thereby increasing the motor's cooling capacity, reducing motor temperature rise, and improving motor service life and reliability.

[0060] Furthermore, the cross-sectional area of ​​the weight reduction hole gradually increases radially from the inside to the outside, so that the effective magnetic cross-section of the second stator tooth at different diameter positions is equal or approximately equal. This not only helps to improve the uniformity of magnetic flux on the second stator tooth, but also improves the overall utilization rate of the iron core.

[0061] The first stator tooth and the adjacent second stator teeth on both sides form the following: Figure 2 The stator slots shown are parallel or near-parallel, i.e., w5=w6 or w5≈w6.

[0062] In a toothed, concentrated winding system, all windings are mounted on the first stator tooth, while there are no coils on the second stator tooth. The number of phases of the motor can also be two-phase, three-phase, four-phase, double three-phase, five-phase, six-phase, seven-phase, etc.

[0063] The concentrated winding includes Ns / 2 concentrated coils 13, and an insulating component 14 is provided between the concentrated coils and the stator core. The insulating component is used for electrical insulation between the winding and the stator magnetic core; where Ns is the number of stator slots.

[0064] The aforementioned insulating components can be directly coated / plastic-coated insulating layers or coated / plated insulating layers on the stator magnetic core, or they can be pre-formed insulating frames assembled onto the iron core, or they can be insulating paper or a combination of the above methods.

[0065] The number of stator slots Ns' in each unit motor satisfies the following calculation formula:

[0066] Ns'=2p'±2;

[0067] in:

[0068] Ns'=Ns / t;

[0069] p'=p / t;

[0070] In the formula, p' is the number of rotor pole pairs in each unit motor; p is the total number of rotor pole pairs of the whole machine.

[0071] t represents the number of unit motors, which is the greatest common divisor of the number of stator slots Ns and the number of rotor pole pairs p. Examples include a 12-slot 14-pole motor (t=1), a 24-slot 28-pole motor (t=2), and a 36-slot 42-pole motor (t=3).

[0072] The high winding coefficient and high slot fill factor concentrated winding of the present invention benefits from the formation of parallel slots (or quasi-parallel slots) between the first stator tooth and the second stator tooth, and the fact that the first stator tooth is a parallel tooth (or quasi-parallel tooth). Therefore, the width of the concentrated coil of the present invention is equal or approximately equal in the radial direction. Moreover, the present invention only requires assembling the pre-formed concentrated coil from the slot opening onto the first stator tooth. While improving the slot fill factor and fundamental winding coefficient, it overcomes the shortcomings of the connection bridge introduced by the tooth and yoke separation scheme and the leakage flux, complex process, and error accumulation that affect batch consistency. Furthermore, it cleverly avoids the coil slot interference problem and the waste of slot space between adjacent coils in traditional integral iron core motors.

[0073] The fundamental winding coefficient K of the motor w Mainly includes the distribution coefficient k d and short moment coefficient k s That is, K w =k d ×k s Because the centralized coil of this invention is only fitted on the first stator tooth, while there is no coil on the second stator tooth.

[0074] According to the distribution coefficient k d The theory is: the magnitude of the vector sum of the potentials of all coils in a phase winding divided by the algebraic sum of the potential magnitudes of all coils in that phase winding. From... Figure 5 It is evident that the potentials of all coils in the in-phase winding of this invention are in phase. Figure 5 Taking phase A as an example, the coil potential vectors of A1 and A2 are in exactly opposite directions (electrical angle difference of 180°), but the directions of the current flowing through A1 and A2 are also exactly opposite (that is, the current inflow and outflow of the two coils in the same phase in the unit motor are exactly reversed, such as...). Figure 7 or Figure 8 As shown), their potentials are in phase. Therefore, the vector sum of the potentials of all coils in the in-phase winding of this invention is equal to their algebraic sum, and thus the distribution coefficient k of this invention is... d =1 (100%), which is necessarily greater than the distribution coefficient of conventional windings.

[0075] Furthermore, each centralized coil is a pre-formed coil with pre-reserved start and end leads 135; the pre-formed coil is pre-formed outside the stator slot, and then assembled from the stator slot opening to the first stator tooth. Then, the pre-reserved start and end leads of each pre-formed coil are directly or indirectly electrically connected, preferably with the following two embodiments.

[0076] Example 1

[0077] The pre-formed coil's lead wires are directly connected (e.g., by welding) according to the winding distribution and phase separation principle.

[0078] Example 2

[0079] The pre-formed coil has reserved start and end leads. By setting a PCB connection board at the end of the motor, the connecting wires are integrated into the PCB connection board. The PCB connection board is set with pads corresponding to the start and end leads. The winding can be made conductive by soldering the pads to the corresponding start and end leads.

[0080] Furthermore, the conductor shape used in each centralized coil can be flat, round, square, or irregular (e.g., the edge of the conductor has grooves or the center of the conductor has flow holes to form a liquid flow path and directly and efficiently cool the conductor); when using flat wire, it can be formed as follows: Figure 4 As shown in the vertical winding method, in this case, the long side of the flat wire vertically wound concentrated coil 134 is wound perpendicular to the side of the stator tooth body; alternatively, it can be done as follows: Figure 3 The flat winding shown is performed in which the long side of the flat wire of the concentrated coil 133 is parallel to the side of the stator tooth body. The size of the conductor used for the coil of the present invention is not limited, so the number of layers wound radially in the slot and the number of layers wound circumferentially can be flexibly designed and adjusted according to actual application requirements.

[0081] Furthermore, the concentrated coils of the same phase windings in one or more unit motors adopt series or parallel continuous windings, preferably including the following embodiments.

[0082] Example 1

[0083] like Figure 6 and Figure 7 As shown, the coils of the same phase windings in a single unit motor are wound continuously together. Each coil contains a cross-layer connecting line 131, and there are continuous winding lines 132 between the coils of the same phase windings in a single unit motor. Continuous winding reduces solder joints (improving reliability and motor efficiency), thereby reducing welding processes and increasing production cycle time.

[0084] Example 2

[0085] like Figure 8 As shown, two coils of the same phase in a unit motor can also be connected in parallel. This is mainly due to the fact that the coil potential phase of the coils of the same phase winding in the unit motor of the present invention is in phase, and the potential and magnetomotive force of different branches can be balanced when connected in parallel.

[0086] Example 3

[0087] like Figure 9 As shown, the multiphase windings of multiple unit motors are connected in a star configuration; in Figure 9 In (a), the in-phase windings of multiple unit motors are connected in series; Figure 9In (b), the in-phase windings of multiple unit motors are connected in parallel. In the figure, A_DM1 refers to the coil group of the first unit motor in phase A. For a three-phase 24-slot 28-pole motor, A_DM1 includes coils A1 and A2, A_DM2 includes coils A3 and A4, and so on.

[0088] Example 4

[0089] like Figure 10 As shown, the multiphase windings of multiple unit motors are connected in a delta configuration; in Figure 10 In (a), the in-phase windings of multiple unit motors are connected in series; Figure 10 In (b), the in-phase windings of multiple unit motors are connected in parallel.

[0090] like Figure 12 As shown, under the constraints of the same stator outer diameter, the same rotor inner diameter, and the same axial length, the output torque of the present invention compared with that of the traditional frameless torque motor shows that the torque output capability of the present invention using flat wire windings is >30% higher than that of the traditional frameless torque motor across the entire load range.

[0091] This invention also provides a rotating device, including the aforementioned frameless motor, a drive controller connected to the lead wire, a reducer, sensors (including a position encoder, a temperature sensor, a current sampler, and a torque sensor (the torque sensor is optional)), and other structural accessories (connectors, fasteners, seals, adhesives, etc.). The reducer can be a planetary reducer, a harmonic reducer, or an RV reducer, etc.

[0092] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various equivalent transformations can be made to the technical solutions of the present invention, and these equivalent transformations all fall within the protection scope of the present invention.

Claims

1. A stator based on a tooth-separated winding, characterized in that: Including alternating tooth integral iron core and tooth-separated concentrated winding; The alternating tooth integral iron core includes first stator teeth and second stator teeth arranged alternately and cyclically along the circumference; The first stator tooth is a parallel tooth or a near-parallel tooth; The second stator tooth is a trapezoidal tooth, and its tooth tip width w3 is smaller than its tooth root width w4; Parallel or near-parallel stator slots are formed between the first stator tooth and the adjacent second stator teeth on both sides; All the tooth-separated concentrated windings are assembled on the first stator tooth.

2. The stator based on tooth-separated windings according to claim 1, characterized in that: Distribution coefficient k of tooth-separated concentrated winding d =1, the potentials of all coils in the same phase winding are in phase.

3. The stator based on tooth-separated windings according to claim 1, characterized in that: The second stator tooth is provided with a weight reduction hole, through which cooling fluid can pass.

4. The stator based on tooth-separated windings according to claim 3, characterized in that: The cross-sectional area of ​​the weight reduction hole gradually increases radially from the inside to the outside, so that the effective magnetic cross-section of the second stator tooth is equal at different diameter positions.

5. The stator based on tooth-separated windings according to claim 1 or 2, characterized in that: The concentrated winding consists of Ns / 2 concentrated coils; where Ns is the number of stator slots; the number of stator slots Ns' in each unit motor satisfies the following calculation formula: Ns'=2p'±2; in: Ns'=Ns / t; p'=p / t; In the formula, p' is the number of rotor pole pairs in each unit motor; p is the number of rotor pole pairs; and t is the number of unit motors.

6. The stator based on tooth-separated windings according to claim 5, characterized in that: Each centralized coil is a pre-formed coil with pre-reserved start and end leads; the pre-formed coil is pre-formed outside the stator slot, and then assembled from the stator slot opening to the first stator tooth. Then, the pre-reserved start and end leads of each pre-formed coil are directly or indirectly connected for electrical conduction.

7. The stator based on tooth-separated windings according to claim 5, characterized in that: In single or multiple unit motors, the concentrated coils of the same phase windings adopt series or parallel continuous windings.

8. The stator based on tooth-separated windings according to claim 5, characterized in that: The conductor used in each centralized coil can be flat, round, square, or irregularly shaped; when flat wire is used, the centralized coil is formed by vertical winding or horizontal winding.

9. A frameless motor, characterized in that: The stator based on tooth-separated windings as described in any one of claims 1-8.

10. A rotating device, characterized in that: Includes the frameless motor as described in claim 9.

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