Borderless Torque Motor Integrated with Multi-Modal Heat Dissipation Structure

Abstract

The present invention discloses a frameless torque motor integrated with a multimodal heat dissipation structure, which includes a plurality of stator cores arranged in a ring shape, including an upper splicing plate. The upper splicing plate is a ring-shaped strip structure, and a block is fixed to the lower part of the upper splicing plate. The heat dissipation efficiency of the frameless torque motor is significantly improved through the multimodal heat dissipation structure. The first, second, and third ventilation holes correspond to each other and are interconnected to form a continuous ventilation channel, which, in cooperation with the honeycomb grille structure below the permanent magnet rotor, optimizes the airflow and increases the heat dissipation area. The high thermal conductivity graphene composite phase change material coating applied in the ventilation holes and the honeycomb grille utilizes the high thermal conductivity and phase change heat absorption characteristics of graphene to effectively manage high temperatures and reduce the temperature rise of the motor. In the scenarios of high load and long-term operation of industrial robots, this design can prevent heat accumulation, extend the service life of the motor, improve the operation stability, meet the high power density requirements, and ensure the continuous and efficient performance of robot joint drives.

Description

Technical Field

[0001] The present invention relates to the field of motor structures, and in particular, to a frameless torque motor integrated with a multimodal heat dissipation structure. Background Art

[0002] With the rapid development of industrial robot technology, the torque motor, as the core component for driving robot joints, directly affects the accuracy, efficiency, and stability of the robot. Existing torque motors usually adopt a permanent magnet synchronous structure, generating a rotating magnetic field through the stator core and winding coils, and cooperating with the permanent magnet rotor to achieve high torque output. In the field of industrial robots, torque motors need to meet the requirements of high power density, fast response, and long-term operation. Traditional motor designs manage the heat during operation by adding heat sinks or fans, and at the same time, adopt a frame structure to ensure mechanical stability. However, these designs limit the compactness and lightweight of the motor to a certain extent and cannot fully meet the requirements of industrial robots for high integration and complex working conditions.

[0003] However, existing torque motors have significant defects in industrial robot applications. First, traditional heat dissipation structures such as heat sinks or single ventilation hole designs have limited heat dissipation efficiency and are difficult to cope with the heat accumulation generated under high loads, resulting in excessive motor temperature rise, which affects the service life and performance. Second, the frame design increases the volume and weight of the motor, which is not conducive to the compact layout of robot joints. In addition, the fixing method of the stator core lacks flexibility, and it is difficult to ensure the assembly accuracy, easily leading to magnetic field asymmetry and reducing the torque output efficiency. Existing motors also do not widely use advanced materials such as graphene composite phase change materials, which limits the further improvement of heat dissipation performance. These defects restrict the application of torque motors in high-precision and high-dynamic industrial robots. Summary of the Invention

[0004] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a frameless torque motor integrated with a multimodal heat dissipation structure.

[0005] The purpose of the present invention is achieved by the following technical solutions:

[0006] The frameless torque motor integrated with a multi-modal heat dissipation structure includes several stator cores arranged in a ring, including an upper splicing plate which is a ring strip structure. A block is fixed to the lower part of the upper splicing plate. A plurality of first ventilation holes penetrate through the upper splicing plate and the block in the vertical direction. A plurality of adjustment holes are arranged at equal intervals from top to bottom on both sides of the block. The adjustment holes are movably fitted inside the adjustment frame and can move vertically within the adjustment frame. Fixing holes corresponding to the adjustment holes are formed on the outer wall of the adjustment frame. The block and the adjustment frame are fixed by a first fixing screw passing through the fixing hole and being threadedly connected to the inside of the fixing hole. A lower splicing plate having the same shape as the upper splicing plate is fixed below the adjustment frame. A plurality of second ventilation holes are formed on the lower splicing plate. A lower bottom plate is fixed to the lower part of the lower splicing plate by a second fixing screw. A plurality of third ventilation holes are formed on the lower bottom plate;

[0007] The permanent magnet rotor is arranged above the stator core and includes several permanent magnets arranged in a ring and corresponding to the several stator cores one by one. A honeycomb grid structure is evenly distributed on the lower part of the permanent magnet. The several permanent magnets are fixed inside the fixing ring;

[0008] It further includes a stator bracket for fixing several stator cores; a PCB arranged below the stator core and fixedly arranged inside the stator bracket; a lower cover plate arranged at the bottom end of the stator bracket; an upper cover plate for fixing the permanent magnet rotor, the upper cover plate is sleeved outside the outer ring of the bearing, and the inner ring of the bearing is sleeved on the side wall of the stator bracket; a winding coil wound around the outside of the stator core.

[0009] Preferably, the upper cover plate includes a cover plate body which is a ring plate structure. An installation part matching the bearing is downwardly extended at the edge of the cover plate body.

[0010] Preferably, an installation ring is arranged on the inner ring of the cover plate body and extends downward to the lower cover plate.

[0011] Preferably, the PCB is electrically connected to the winding coil for controlling the current of the winding coil.

[0012] Preferably, the several first ventilation holes, the several second ventilation holes and the several third ventilation holes correspond to each other one by one.

[0013] Preferably, the several first ventilation holes, the several second ventilation holes and the several third ventilation holes are interconnected to form a continuous ventilation channel.

[0014] Preferably, a high thermal conductivity graphene composite phase change material coating is applied inside the honeycomb grid structure.

[0015] Preferably, the inner walls of the several first ventilation holes, the several second ventilation holes and the several third ventilation holes are all coated with a high thermal conductivity graphene composite phase change material coating.

[0016] Preferably, the movable cooperation between the adjustment hole and the adjustment frame realizes multi-level positioning adjustment through a plurality of fixing holes and a first fixing screw.

[0017] Preferably, the stator bracket and the lower cover plate are fixed by threaded connection to form a closed bottom structure.

[0018] The advantages and beneficial effects of the present invention compared to the prior art are as follows:

[0019] 1. The present invention is a frameless torque motor with an integrated multi-modal heat dissipation structure, which significantly improves the heat dissipation efficiency through the multi-modal heat dissipation structure. The first, second, and third air vents correspond to each other and are interconnected to form a continuous ventilation channel, which cooperates with the honeycomb grid structure at the bottom of the permanent magnet rotor to optimize the airflow and increase the heat dissipation area. The high thermal conductivity graphene composite phase change material coating coated in the air vents and honeycomb grids utilizes the high thermal conductivity and phase change heat absorption characteristics of graphene to effectively manage high temperatures and reduce the temperature rise of the motor. In scenarios where industrial robots are under high load and run for a long time, this design can prevent heat accumulation, extend the life of the motor, improve operational stability, meet high power density requirements, and ensure the continued high efficiency performance of the robot joint drive.

[0020] 2. The frameless torque motor of the present invention abandons the traditional frame structure through design, which significantly reduces the volume and weight. The upper cover adopts an annular plate structure, equipped with a mounting portion and a mounting ring extending to the lower cover, which closely cooperates with the bearing and stator bracket to form a compact layout. The modular design of the stator core and rotor further reduces the use of materials, and combines high-precision bearings to reduce friction and achieve lightweight. This compact and lightweight feature is particularly important in the joint drive of industrial robots. It can improve the overall flexibility and energy efficiency of the robot, adapt to high-precision application scenarios with limited space, such as precision assembly or collaborative robots, and ensure high dynamic response and high integration.

[0021] 3. The stator core of the present invention supports multi-level positioning fine-tuning in the vertical direction through the active cooperation of the adjustment hole and the adjustment frame, which significantly improves the assembly flexibility and accuracy. The adjustment frame and the block are stably connected through fixing holes and screws to ensure high-precision alignment of the stator core and the permanent magnet rotor, optimize the magnetic field distribution, reduce magnetic leakage, and improve the torque output efficiency. In industrial robot applications, this adjustable design can effectively deal with manufacturing errors, adapt to dynamic adjustment requirements under complex working conditions, ensure the stability and high precision of the robot's joint movement, and is particularly suitable for high-precision processing, detection or medical robots and other scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A structural diagram of a frameless torque motor with an integrated multi-modal heat dissipation structure according to an embodiment of the present invention;

[0023] Figure 2 for Figure 1Exploded structural schematic diagram of the frameless torque motor with an integrated multimodal heat dissipation structure shown;

[0024] Figure 3 Structural schematic diagram of the stator core and winding coil of the present invention in a connected state;

[0025] Figure 4 Exploded structural schematic diagram of the winding coil of the present invention;

[0026] Figure 5 Exploded structural schematic diagram of the permanent magnet rotor of the present invention;

[0027] Figure 6 is Figure 5 Enlarged structural schematic diagram of the local part at A in;

[0028] Figure 7 is Figure 1 Structural schematic diagram of the upper cover plate shown.

[0029] In the figure: 1, stator bracket; 2, bearing; 3, PCB; 4, lower cover plate; 5, stator core; 501, upper splicing plate; 502, first ventilation hole; 503, block; 504, adjustment hole; 505, adjustment frame; 506, fixing hole; 507, first fixing screw; 508, lower splicing plate; 509, second ventilation hole; 510, lower bottom plate; 511, third ventilation hole; 512, second fixing screw; 6, permanent magnet rotor; 601, permanent magnet; 602, honeycomb grille structure; 603, fixing ring; 7, upper cover plate; 701, cover plate body; 702, installation part; 703, installation ring; 8, winding coil. Detailed implementation manners

[0030] For the convenience of understanding the present invention, the present invention will be described more comprehensively below with reference to the relevant drawings. The preferred embodiments of the present invention are shown in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the disclosure of the present invention more thorough and comprehensive.

[0031] Please refer to Figures 1 to 7, A frameless torque motor integrated with a multi-modal heat dissipation structure, comprising: a plurality of stator cores 5 arranged in a ring, including an upper splicing plate 501, the upper splicing plate 501 being a ring-shaped strip structure, a block 503 being fixed to the lower part of the upper splicing plate 501, a plurality of first ventilation holes 502 penetrating through the upper splicing plate 501 and the block 503 in the vertical direction, a plurality of adjustment holes 504 arranged at equal intervals from top to bottom being provided on both sides of the block 503, the adjustment holes 504 being movably fitted inside an adjustment frame 505 and being movable vertically within the adjustment frame 505, a fixing hole 506 corresponding to the adjustment hole 504 being formed on the outer wall of the adjustment frame 505, and the block 503 and the adjustment frame 505 being fixed by a first fixing screw 507 passing through the fixing hole 506 and being threadedly connected to the inside of the fixing hole 506, a lower splicing plate 508 having the same shape as the upper splicing plate 501 being fixed below the adjustment frame 505, a plurality of second ventilation holes 509 being formed on the lower splicing plate 508, a lower bottom plate 510 being fixed to the lower part of the lower splicing plate 508 by a second fixing screw 512, and a plurality of third ventilation holes 511 being formed on the lower bottom plate 510; a permanent magnet rotor 6, arranged above the stator core 5, including a plurality of permanent magnets 601 arranged in a ring and corresponding to the plurality of stator cores 5 one by one, a honeycomb grille structure 602 being uniformly distributed below the permanent magnet 601, and the plurality of permanent magnets 601 being fixed inside a fixing ring 603; a stator bracket 1 for fixing the plurality of stator cores 5; a PCB 3 arranged below the stator core 5 and fixedly arranged inside the stator bracket 1; a lower cover plate 4 arranged at the bottom end of the stator bracket 1; an upper cover plate 7 for fixing the permanent magnet rotor 6, the upper cover plate 7 being sleeved outside the outer ring of a bearing 2, and the inner ring of the bearing 2 being sleeved on the side wall of the stator bracket 1; and a winding coil 8 wound around the outside of the stator core 5.

[0032] In this embodiment, the stator core 5 forms a modular structure through the upper splicing plate 501, the block 503, the lower splicing plate 508 and the lower bottom plate 510, and is provided with the first ventilation holes 502, the second ventilation holes 509 and the third ventilation holes 511 to form a through ventilation channel, improving the heat dissipation efficiency. The adjustment holes 504 and the adjustment frame 505 cooperate with the first fixing screw 507 to realize the vertical fine adjustment of the stator core 5, ensuring high-precision alignment with the permanent magnet rotor 6. The honeycomb grille structure 602 of the permanent magnet rotor 6 optimizes the air flow and enhances the heat dissipation. The stator bracket 1, the PCB 3, the lower cover plate 4, the upper cover plate 7 and the bearing 2 form a compact support system, and the winding coil 8 provides efficient electromagnetic drive, realizing high torque output, light weight and long life as a whole, and being suitable for industrial robot applications.

[0033] In the present invention, the upper cover plate 7 includes a cover plate body 701, the cover plate body 701 being a ring-shaped plate structure, and an installation portion 702 matching the bearing 2 being downwardly extended at the edge of the cover plate body 701.

[0034] In this embodiment, the upper cover plate 7 realizes the fixation and smooth rotation of the permanent magnet rotor 6 through its structural design. The cover plate body 701 adopts an annular plate-like structure, optimizing space utilization and reducing the overall volume of the motor, meeting the compactness requirements of the frameless torque motor. The mounting portion 702 extending downward from the edge of the cover plate body 701 is precisely matched with the outer ring of the bearing 2, ensuring the stable connection between the upper cover plate 7 and the bearing 2, supporting the high-speed rotation of the permanent magnet rotor 6, and reducing friction and vibration. This design enhances the mechanical stability of the motor while maintaining the lightweight characteristic, being suitable for high-precision and high-dynamic scenarios such as industrial robot joint drives, and improving the smoothness and durability of torque output.

[0035] In the present invention, an installation ring 703 extending downward and reaching the lower cover plate 4 is provided on the inner ring of the cover plate body 701.

[0036] In this embodiment, the inner ring of the cover plate body 701 enhances the structural integrity and protection performance of the frameless torque motor through the design of the installation ring 703. The installation ring 703 extends downward to the lower cover plate 4 to form a closed connection structure, effectively preventing dust and foreign objects from entering the interior of the motor, and improving durability and reliability. The annular plate-like design of the cover plate body 701 combined with the installation ring 703 optimizes the cooperation between the upper cover plate 7 and the lower cover plate 4, maintains the compactness of the motor, and reduces space occupation. This design is particularly important in industrial robot joint drives, ensuring the stable operation of the motor under complex working conditions, extending the service life, while supporting the requirements of high precision and high dynamic response, and improving the overall performance.

[0037] In the present invention, the PCB 3 is electrically connected to the winding coil 8 for controlling the current of the winding coil 8.

[0038] In this embodiment, the PCB 3 realizes the precise control of the current of the frameless torque motor by being electrically connected to the winding coil 8, significantly improving the electromagnetic drive efficiency. The PCB 3 serves as the control center, managing the current input of the winding coil 8, generating a stable rotating magnetic field, and interacting with the permanent magnet rotor 6 to produce a high torque output. This precise control ensures the rapid response and high-precision operation of the motor in industrial robot joint drives, meeting the dynamic requirements under complex working conditions. The PCB 3 is fixed within the stator bracket 1, with a compact structure, and in cooperation with the optimized layout of the winding coil 8, reduces energy loss, improves the overall energy efficiency of the motor, and provides reliable power support for high-performance industrial robots.

[0039] In the present invention, a plurality of first ventilation holes 502, a plurality of second ventilation holes 509, and a plurality of third ventilation holes 511 correspond to each other one by one.

[0040] In this embodiment, a number of first ventilation holes 502, second ventilation holes 509 and third ventilation holes 511, through a one-to-one correspondence design, significantly improve the heat dissipation efficiency of the frameless torque motor. These ventilation holes are respectively arranged on the upper splicing plate 501 and the block 503, the lower splicing plate 508 and the lower bottom plate 510, and their precise alignment ensures the smooth flow of air in the stator core 5, forming an efficient heat dissipation channel. This design effectively reduces the temperature rise of the motor during high-load operation, extends its service life, and is particularly suitable for high-power density scenarios such as industrial robot joint drives. The one-to-one ventilation hole structure also optimizes the thermal management of the stator core 5, and cooperates with other heat dissipation components to improve the overall stability and performance of the motor.

[0041] In the present invention, a number of first ventilation holes 502, a number of second ventilation holes 509 and a number of third ventilation holes 511 communicate with each other to form a continuous ventilation channel.

[0042] In this embodiment, a number of first ventilation holes 502, second ventilation holes 509 and third ventilation holes 511, through a mutually connected design, form a continuous ventilation channel, greatly improving the heat dissipation performance of the frameless torque motor. These ventilation holes are respectively located on the upper splicing plate 501 and the block 503, the lower splicing plate 508 and the lower bottom plate 510, penetrate the stator core 5, ensure the smooth flow of air from the top to the bottom, and effectively discharge the heat generated during operation. This continuous heat dissipation channel reduces the temperature rise of the motor, enhances the stability during long-term operation, and is particularly suitable for high-load scenarios such as industrial robot joint drives. In combination with other heat dissipation structures, this design optimizes thermal management, improves the efficiency and service life of the motor, and provides reliable support for high-performance robots.

[0043] In the present invention, the honeycomb grid structure 602 is coated with a high thermal conductivity graphene composite phase change material coating.

[0044] In this embodiment, the honeycomb grid structure 602 is coated with a high thermal conductivity graphene composite phase change material coating, significantly improving the heat dissipation performance of the frameless torque motor. The honeycomb grid structure 602 is located below the permanent magnet 601, increasing the heat dissipation area and optimizing the air flow. The graphene composite phase change material coating utilizes the high thermal conductivity (about 5000 W / m·K) of graphene and the phase change heat absorption characteristics, and effectively manages the high temperature during the operation of the permanent magnet rotor 6 through rapid heat conduction and latent heat absorption. This design reduces the temperature rise, extends the service life of the motor, enhances the operation stability, and is particularly suitable for high-power density scenarios such as industrial robot joint drives. The combination of the coating and the honeycomb grid structure 602 optimizes thermal management and provides guarantee for the efficient operation of the motor.

[0045] In the present invention, the inner walls of a number of first ventilation holes 502, a number of second ventilation holes 509 and a number of third ventilation holes 511 are all coated with a high thermal conductivity graphene composite phase change material coating.

[0046] In this embodiment, the inner walls of a number of first ventilation holes 502, second ventilation holes 509, and third ventilation holes 511 are coated with a high thermal conductivity graphene composite phase change material coating, significantly improving the heat dissipation efficiency of the frameless torque motor. These ventilation holes are respectively located between the upper splicing plate 501 and the block 503, the lower splicing plate 508, and the lower bottom plate 510, forming a through ventilation channel for the stator core 5. The graphene composite phase change material coating utilizes the high thermal conductivity of graphene, approximately 5000 W / m·K, and the phase change heat absorption characteristic to quickly conduct heat and manage high temperatures through latent heat absorption, effectively reducing the motor temperature rise. This design enhances the operating stability and extends the service life, being particularly suitable for high-load scenarios of industrial robots, optimizing thermal management, and providing guarantee for efficient operation.

[0047] In the present invention, the movable cooperation between the adjustment hole 504 and the adjustment frame 505 is achieved through a plurality of fixing holes 506 and the first fixing screw 507 for multi-level positioning adjustment.

[0048] In this embodiment, the movable cooperation between the adjustment hole 504 and the adjustment frame 505 through a plurality of fixing holes 506 and the first fixing screw 507 realizes the multi-level positioning adjustment of the stator core 5, significantly improving the assembly accuracy and flexibility of the frameless torque motor. The adjustment holes 504 are arranged equidistantly on both sides of the block 503. Cooperating with the inner wall of the adjustment frame 505, it allows the stator core 5 to be finely adjusted in the vertical direction. The multi-level fixing holes 506 lock the position through the first fixing screw 507 to ensure high-precision alignment with the permanent magnet rotor 6. This design optimizes the magnetic field distribution, reduces magnetic leakage, and improves the torque output efficiency, being particularly suitable for high-precision scenarios such as joint drives of industrial robots, meeting the dynamic adjustment requirements of complex working conditions, and enhancing the motor performance and stability.

[0049] In the present invention, the stator bracket 1 and the lower cover plate 4 are fixed by threaded connection to form a closed bottom structure.

[0050] In this embodiment, the stator bracket 1 and the lower cover plate 4 are fixed by threaded connection to form a closed bottom structure, effectively enhancing the protection performance and structural stability of the frameless torque motor. The stator bracket 1 supports the stator core 5 and the PCB 3, while the lower cover plate 4 is tightly combined with the stator bracket 1 through threaded connection to prevent dust and foreign objects from entering the motor interior, improving the durability and reliability. This closed design optimizes the bottom space of the motor, maintains compactness, and is suitable for space-limited scenarios such as joint drives of industrial robots. The stability of the threaded connection ensures that the motor maintains its structural integrity during high-dynamic operation, extends the service life, and provides reliable support for high-precision and high-load robot applications.

[0051] The above-described embodiments merely represent several embodiments of the present invention. The description thereof is relatively specific and detailed, but it should not be construed as a limitation on the scope of the present invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all fall within the protection scope of the present invention. Therefore, the protection scope of the present invention patent shall be subject to the appended claims.

Claims

1. The frameless torque motor integrated with a multimodal heat dissipation structure is characterized in that Comprising: A plurality of stator cores arranged in a ring, including an upper splicing plate. The upper splicing plate is a ring-shaped strip structure. A block is fixed to the lower part of the upper splicing plate. A plurality of first ventilation holes penetrate through the upper splicing plate and the block in the vertical direction. On both sides of the block, a plurality of adjustment holes are arranged at equal intervals from top to bottom. The adjustment holes are movably fitted inside an adjustment frame and can move vertically within the adjustment frame. Fixing holes corresponding to the adjustment holes are formed on the outer wall of the adjustment frame. The block and the adjustment frame are fixed by a first fixing screw passing through the fixing hole and being threadedly connected to the inside of the fixing hole. A lower splicing plate having the same shape as the upper splicing plate is fixed below the adjustment frame. A plurality of second ventilation holes are formed in the lower splicing plate. A lower bottom plate is fixed to the lower part of the lower splicing plate by a second fixing screw. A plurality of third ventilation holes are formed in the lower bottom plate; A permanent magnet rotor, arranged above the stator core, including a plurality of permanent magnets arranged in a ring and corresponding to the plurality of stator cores one by one. A honeycomb grid structure is uniformly distributed at the lower part of the permanent magnet. The plurality of permanent magnets are fixed inside a fixing ring; It further includes a stator bracket for fixing the plurality of stator cores, a PCB arranged below the stator core and fixedly arranged inside the stator bracket, a lower cover plate arranged at the bottom end of the stator bracket, an upper cover plate for fixing the permanent magnet rotor. The upper cover plate is sleeved on the outer side of the outer ring of the bearing. The inner ring of the bearing is sleeved on the side wall of the stator bracket, and a winding coil wound around the outer part of the stator core.

2. The frameless torque motor with an integrated multimodal heat dissipation structure according to claim 1, wherein, The upper cover plate includes a cover plate body. The cover plate body is a ring-shaped plate structure. An installation part matching the bearing extends downward at the edge of the cover plate body.

3. The frameless torque motor with an integrated multimodal heat dissipation structure according to claim 2, wherein An installation ring extending downward and extending to the lower cover plate is arranged on the inner ring of the cover plate body.

4. The frameless torque motor with an integrated multi-modal heat dissipation structure according to claim 1, wherein, The PCB is electrically connected to the winding coil and is used to control the current of the winding coil.

5. The frameless torque motor with an integrated multimodal heat dissipation structure according to claim 1, characterized in that, The plurality of first ventilation holes, the plurality of second ventilation holes and the plurality of third ventilation holes correspond to each other one by one.

6. The frameless torque motor with an integrated multimodal heat dissipation structure according to claim 1, characterized in that, The plurality of first ventilation holes, the plurality of second ventilation holes and the plurality of third ventilation holes are interconnected to form a continuous ventilation channel.

7. The frameless torque motor with an integrated multimodal heat dissipation structure according to claim 1, characterized in that, A high thermal conductivity graphene composite phase change material coating is applied inside the honeycomb grid structure.

8. The frameless torque motor with an integrated multimodal heat dissipation structure according to claim 1, wherein High thermal conductivity graphene composite phase change material coatings are applied to the inner walls of the plurality of first ventilation holes, the plurality of second ventilation holes and the plurality of third ventilation holes.

9. The frameless torque motor with an integrated multimodal heat dissipation structure according to claim 1, characterized in that, The movable fit between the adjustment holes and the adjustment frame realizes multi-level positioning adjustment through a plurality of fixing holes and the first fixing screw.

10. The frameless torque motor with an integrated multimodal heat dissipation structure according to claim 1, characterized in that, The stator bracket and the lower cover plate are fixed by threaded connection to form a closed bottom structure.

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