Hollow cup brushless motor

Abstract

This utility model discloses a hollow cup brushless motor, relating to the field of motor technology. The hollow cup brushless motor includes a housing, a rotor assembly, a stator assembly, a circuit board assembly, and a drive board assembly. The housing has a rotating cavity and a connecting surface located outside the rotating cavity; the rotor assembly is rotatably disposed within the rotating cavity; the stator assembly is disposed on the inner wall of the rotating cavity and is used to drive the rotor assembly to rotate; the circuit board assembly is disposed within the rotating cavity and is electrically connected to the stator assembly; the drive board assembly is disposed on the connecting surface and is electrically connected to the circuit board assembly via a connector. The technical solution provided by this utility model aims to simultaneously apply two control methods, reduce the size of the motor, and facilitate the maintenance of the drive board assembly.

Description

Technical Field

[0001] This utility model relates to the field of motor technology, and in particular to a hollow cup brushless motor. Background Technology

[0002] A coreless brushless motor is a type of DC permanent magnet servo micro-motor. Its main characteristic is the absence of slots in the armature core, with the windings manufactured into a cup shape using a special process. Compared to traditional cogging motors, coreless brushless motors have significantly higher efficiency, mostly exceeding 70%, with some approaching 90%, while the efficiency of traditional cogging motors is generally below 70%. Furthermore, coreless brushless motors offer advantages such as small size, light weight, and high power and torque density, reducing size and weight by approximately 30% compared to traditional motors. Simultaneously, coreless brushless motors exhibit superior control performance; the absence of cogging effect results in minimal torque fluctuation and smooth operation. Moreover, they possess a low electromechanical time constant, excellent dynamic response, and low inductance. The electrical time constant is typically within 0.1ms, while the electromechanical time constant is approximately 2ms, enabling rapid response and precise control. This makes them suitable for high-precision drive systems in fields such as communications, robotics, security, aerospace, and steering systems.

[0003] In existing coreless brushless motors, a typical structure consists of a stator assembly, a rotor assembly, front and rear end covers, and a circuit board. Control methods are categorized into two types: Hall effect and Hall effect-free. Hall effect control generally employs a built-in circuit board design, integrating the circuit board inside the motor and working in conjunction with a driver board to achieve precise motor control. Hall effect-free control, on the other hand, relies solely on the driver board to control the motor's operation, in which case the driver board handles all control functions.

[0004] This configuration results in both the drive board assembly and the circuit board assembly being housed within the rotating cavity of the housing. The space within the rotating cavity is overly cramped, leading to potential interference between components and poor heat dissipation. To avoid interference, the space within the rotating cavity is typically increased; however, this increases the size of the motor and raises costs. Furthermore, since the drive board assembly is a consumable component, its location within the rotating cavity hinders maintenance. Utility Model Content

[0005] The main purpose of this invention is to propose a hollow cup brushless motor that is suitable for both control methods, reduces the size of the motor, and facilitates the maintenance of the drive board assembly.

[0006] To achieve the above objectives, this utility model proposes a hollow cup brushless motor, which includes:

[0007] A housing, wherein the housing is provided with a rotating cavity and a connecting surface located on the outer side of the rotating cavity;

[0008] A rotor assembly, wherein the rotor assembly is rotatably disposed within the rotating cavity;

[0009] A stator assembly, disposed on the inner wall of the rotating cavity, is used to drive the rotor assembly to rotate;

[0010] A circuit board assembly, wherein the circuit board assembly is disposed within the rotating cavity and electrically connected to the stator assembly; and

[0011] A driver board assembly is disposed on the connecting surface and electrically connected to the circuit board assembly via a connector.

[0012] In one embodiment, the housing includes a main body and a rear end cover. The main body has the rotating cavity and an opening communicating with the rotating cavity. The rear end cover is disposed at the opening, and the connecting surface is formed on the side of the rear end cover facing away from the rotating cavity.

[0013] The circuit board assembly is disposed between the stator assembly and the rear end cover, and a first gap space is provided between the circuit board assembly and the rear end cover.

[0014] In one embodiment, the hollow cup brushless motor further includes a bracket disposed on the inner wall of the rotating cavity, one side of the bracket abutting against the stator assembly, the other side of the bracket forming a mounting surface, and the circuit board assembly being confined to the mounting surface, so that the first gap space is provided between the circuit board assembly and the rear end cover.

[0015] In one embodiment, the rear end cover has a notch that communicates with the rotating cavity, the connector passes through the notch, and both ends of the connector are connected to the circuit board assembly and the drive board assembly, respectively.

[0016] In one embodiment, the bracket is further provided with a limiting baffle, which corresponds to the notch.

[0017] In one embodiment, the bracket is provided with a plurality of limiting posts in the circumferential direction, and the circuit board assembly is provided with a plurality of limiting grooves in the circumferential direction, and each of the limiting posts corresponds to a limiting groove.

[0018] When the circuit board assembly is disposed on the mounting surface, the limiting post is inserted into the limiting groove and aligned with the outer wall of the circuit board assembly along the circumferential direction of the circuit board assembly.

[0019] In one embodiment, the rear end cover includes a base portion and a hanging ear portion disposed at one end of the base portion. The base portion is inserted into the rotating cavity so that the hanging ear portion abuts against the opening of the main body portion.

[0020] In one embodiment, a cable is provided on the side of the drive board assembly facing away from the connection surface. The cable and the connector are symmetrically arranged on both sides of the drive board assembly, and the cable is used to connect to other devices.

[0021] In one embodiment, the circuit board assembly is a Hall plate, the Hall plate includes a substrate and a plurality of Hall sensors disposed on the substrate. The plurality of Hall sensors are located on the side of the substrate facing the rotor assembly and are electrically connected to the substrate. The Hall sensors are used to detect the rotation of the rotor assembly. The side of the substrate facing the rotor assembly is electrically connected to the stator assembly, and the other side of the substrate is electrically connected to the drive board assembly through the connector.

[0022] In one embodiment, the circuit board assembly is a terminal block, with one side of the terminal block facing the stator assembly electrically connected to the stator assembly, and the other side of the terminal block electrically connected to the drive board assembly via the connector.

[0023] The technical solution of this utility model involves placing the circuit board assembly inside the rotating cavity, while the drive board assembly is located on the connecting surface of the housing and electrically connected to the circuit board assembly via a connector. This not only facilitates quick replacement and maintenance of the drive board assembly but also reduces the space of the rotating cavity, achieving motor miniaturization. Furthermore, the control method can be changed by replacing the circuit board assembly, thereby improving overall flexibility. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0025] Figure 1 A schematic diagram of a hollow cup brushless motor according to an embodiment of the present invention;

[0026] Figure 2 for Figure 1 Cross-sectional view of a hollow cup brushless motor;

[0027] Figure 3 for Figure 1 A partial structural diagram of the circuit board assembly when it is a connector board;

[0028] Figure 4 for Figure 1 A partial structural diagram of the circuit board assembly when it is a Hall plate;

[0029] Figure 5 for Figure 1 A partial structural diagram from another perspective when the circuit board assembly is a Hall plate;

[0030] Figure 6 for Figure 1 A schematic diagram of the middle part of the structure.

[0031] Explanation of icon numbers:

[0032] 100. Hollow Cup Brushless Motor; 1. Housing; 11. Main Body; 111. Rotating Cavity; 112. Opening; 12. Rear End Cover; 121. Connecting Surface; 122. First Gap Space; 123. Notch; 124. Base; 125. Lug; 2. Rotor Assembly; 21. Shaft; 22. Magnetic Ring; 3. Stator Assembly; 31. Iron Core; 32. Armature Coil Cup; 4. Circuit Board Assembly; 41. Limiting Slot; 42. Hall Sensor; 43. Terminal Block; 5. Drive Board Assembly; 51. Cable; 6. Connector; 7. Bracket; 71. Mounting Surface; 72. Limiting Baffle; 73. Limiting Post; 8. Support Ring; 81. Second Gap Space.

[0033] The realization of the purpose, functional features and advantages of this utility model will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0034] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0035] It should be noted that if the embodiments of this utility model involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.

[0036] Furthermore, if the embodiments of this utility model involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

[0037] A coreless brushless motor is a type of DC permanent magnet servo micro-motor. Its main characteristic is the absence of slots in the armature core, with the windings manufactured into a cup shape using a special process. Compared to traditional cogging motors, coreless brushless motors have significantly higher efficiency, mostly exceeding 70%, with some approaching 90%, while the efficiency of traditional cogging motors is generally below 70%. Furthermore, coreless brushless motors offer advantages such as small size, light weight, and high power and torque density, reducing size and weight by approximately 30% compared to traditional motors. Simultaneously, coreless brushless motors exhibit superior control performance; the absence of cogging effect results in minimal torque fluctuation and smooth operation. Moreover, they possess a low electromechanical time constant, excellent dynamic response, and low inductance. The electrical time constant is typically within 0.1ms, while the electromechanical time constant is approximately 2ms, enabling rapid response and precise control. This makes them suitable for high-precision drive systems in fields such as communications, robotics, security, aerospace, and steering systems.

[0038] In existing coreless brushless motors, a typical structure consists of a stator assembly, a rotor assembly, front and rear end covers, and a circuit board. Control methods are categorized into two types: Hall effect and Hall effect-free. Hall effect control generally employs a built-in circuit board design, integrating the circuit board inside the motor and working in conjunction with a driver board to achieve precise motor control. Hall effect-free control, on the other hand, relies solely on the driver board to control the motor's operation, in which case the driver board handles all control functions.

[0039] Existing coreless brushless motors suffer from inconsistent structures under different control methods. When using Hall effect control, a circuit board and driver board need to be installed inside the motor; however, when using Hall effect-less control, the driver board's mounting structure differs. This makes it difficult to flexibly switch between control methods when adjustments are needed, increasing production complexity and causing inconvenience to users.

[0040] Furthermore, the rotating cavity of the housing houses both the drive board assembly and the circuit board assembly, making the space within the rotating cavity too cramped. This can easily lead to interference between components and poor heat dissipation. To avoid interference, the space within the rotating cavity is usually increased; however, this increases the size of the motor and raises costs. Additionally, since the drive board assembly is a consumable component, its location within the rotating cavity makes maintenance inconvenient.

[0041] The main purpose of this utility model is to propose a hollow cup brushless motor 100, which aims to simultaneously apply two control methods, reduce the size of the motor, facilitate the maintenance of the drive board assembly, and increase the flexibility of adjustment.

[0042] Please see Figures 1 to 6 In one embodiment of this utility model, the hollow cup brushless motor 100 includes a housing 1, a rotor assembly 2, a stator assembly 3, a circuit board assembly 4, and a drive board assembly 5. The housing 1 has a rotating cavity 111 and a connecting surface 121 located outside the rotating cavity 111. The rotor assembly 2 is rotatably disposed within the rotating cavity 111, and the stator assembly 3 is disposed on the inner wall of the rotating cavity 111 for driving the rotor assembly 2 to rotate. The circuit board assembly 4 is disposed within the rotating cavity 111 and electrically connected to the stator assembly 3. The drive board assembly 5 is disposed on the connecting surface 121 and electrically connected to the circuit board assembly 4 via a connector 6.

[0043] The technical solution of this utility model effectively utilizes the internal space and reduces the external volume occupied by placing the circuit board assembly 4 inside the rotating cavity 111. Meanwhile, the drive board assembly 5 is located on the connecting surface 121 of the housing 1 and is electrically connected to the circuit board assembly 4 via the connector 6. This not only facilitates the quick replacement and maintenance of the drive board assembly 5 but also reduces the space of the rotating cavity 111, achieving motor miniaturization. Furthermore, the control method can be changed by replacing the circuit board assembly 4, thereby improving overall flexibility.

[0044] Understandably, the drive board is a consumable component, and its placement on the outside of the transmission cavity facilitates disassembly, assembly, and maintenance. If the drive board were internal, and the hollow cup brushless motor 100 was small in size while requiring Hall effect control, the electronic components on the circuit board assembly 4 might not be able to fit.

[0045] Please see Figure 2 In one embodiment, the stator assembly 3 includes a stator core 31 and an armature coil cup 32. The stator core 31 is disposed around the inner wall of the rotating cavity 111 and abuts against the circuit board assembly 4. The armature coil cup 32 is disposed on the inner wall of the core 31 and is electrically connected to the circuit board assembly 4.

[0046] In this embodiment, the stator core 31 is typically made of silicon steel sheets stacked into a ring and mounted on the inner wall of the rotating cavity 111 to generate a magnetic field. The armature coil cup 32 is mounted on the inner side of the stator core 31 and is typically composed of multiple windings to conduct current and interact with the magnetic field of the rotor assembly 2.

[0047] Please see Figure 2 In one embodiment, the rotor assembly 2 includes a rotating shaft 21 disposed in the rotating cavity 111 and a magnetic ring 22 sleeved on the rotating shaft 21.

[0048] In this embodiment, the rotating shaft 21 is rotatably disposed within the rotating cavity 111 to support the magnetic ring 22 and transmit torque. The magnetic ring 22 is sleeved on the rotating shaft 21 and is typically made of permanent magnet material. It is used to generate a rotating magnetic field and interact with the armature coil of the stator assembly 3 to drive the rotating shaft 21 to rotate.

[0049] Please see Figure 1 , Figure 2 and Figure 6 In one embodiment, the housing 1 includes a main body 11 and a rear end cover 12. The main body 11 forms a rotating cavity 111 and an opening 112 communicating with the rotating cavity 111. The rear end cover 12 is disposed at the opening 112, and a connecting surface 121 is formed on the side of the rear end cover 12 facing away from the rotating cavity 111. The circuit board assembly 4 is disposed between the stator assembly 3 and the rear end cover 12, and a first gap space 122 is provided between the circuit board assembly 4 and the rear end cover 12.

[0050] In this embodiment, the main body 11 of the housing 1 forms a rotating cavity 111 to accommodate the rotor assembly 2 and the stator assembly 3. The rear end cover 12 is installed at the opening 112 of the main body 11, and a connecting surface 121 is formed on the side of the rear end cover 12 facing away from the rotating cavity 111 for mounting the drive board assembly 5. A first gap space 122 is provided between the circuit board assembly 4 and the rear end cover 12 to prevent electronic components or contact terminals on the circuit board assembly 4 from contacting the rear end cover 12 and causing a short circuit. Simultaneously, the first gap space 122 also facilitates the installation of the hollow cup brushless motor 100.

[0051] Optionally, the rear cover 12 and the main body 11 can be detachably connected by means of threaded connection or riveting, which facilitates maintenance.

[0052] Please see Figure 2 and Figure 6 In one embodiment, the hollow cup brushless motor 100 further includes a bracket 7 disposed on the inner wall of the rotating cavity 111. One side of the bracket 7 abuts against the stator assembly 3, and the other side of the bracket 7 forms a mounting surface 71. The circuit board assembly 4 is limited to the mounting surface 71 so that a first gap space 122 is provided between the circuit board assembly 4 and the rear end cover 12.

[0053] In this embodiment, the bracket 7 is installed on the inner wall of the rotating cavity 111. One side of the bracket 7 abuts against the stator assembly 3, and the other side forms a mounting surface 71 for fixing the circuit board assembly 4. The bracket 7 is used to ensure that a first gap space 122 can be provided between the circuit board assembly 4 and the rear cover 12, and at the same time, it can provide support for the circuit board assembly 4.

[0054] Please see Figure 1 and Figure 6 In one embodiment, the rear cover 12 is provided with a notch 123, which communicates with the rotating cavity 111. The connector 6 passes through the notch 123, and the two ends of the connector 6 are respectively connected to the circuit board assembly 4 and the drive board assembly 5.

[0055] In this embodiment, the notch 123 is used to accommodate the connector 6, so that after the connector 6 passes through the notch 123, one end is connected to the circuit board assembly 4 and the other end is connected to the drive board assembly 5, thereby realizing the electrical connection between the two.

[0056] It should be noted that in this embodiment, the connector 6 is a steel pin, which is easy to weld and has a strong and reliable characteristic. At the same time, using a steel pin for connection does not occupy too much space, further reducing the size of the hollow cup brushless motor 100.

[0057] Optionally, an insulating material can be applied to the outside of the steel needle to prevent accidental contact between the steel needle and other electronic components or contact terminals.

[0058] Please see Figure 3 In one embodiment, the bracket 7 is further provided with a limiting baffle 72, which corresponds to the notch 123.

[0059] In this embodiment, the limiting baffle 72 corresponds to the notch 123 of the rear cover 12, and is used to prevent the connector 6 from being displaced during operation and accidentally touching other electronic components or contact terminals.

[0060] Please see Figure 3 and Figure 5 In one embodiment, the bracket 7 is provided with a plurality of limiting posts 73 in the circumferential direction, and the circuit board assembly 4 is provided with a plurality of limiting grooves 41 in the circumferential direction, with each limiting post 73 corresponding to a limiting groove 41. When the circuit board assembly 4 is disposed on the mounting surface 71, the limiting posts 73 are inserted into the limiting grooves 41, and along the circumferential direction of the circuit board assembly 4, the limiting posts 73 are aligned with the outer sidewall of the circuit board assembly 4.

[0061] In this embodiment, the bracket 7 is provided with multiple limiting posts 73 in the circumferential direction, and the circuit board assembly 4 is provided with multiple limiting grooves 41 in the circumferential direction, with each corresponding to the other. When the circuit board assembly 4 is installed on the mounting surface 71 of the bracket 7, the limiting posts 73 are inserted into the limiting grooves 41 to ensure the circuit board assembly 4 is fixed and to prevent the circuit board assembly 4 from shifting during operation.

[0062] Understandably, the alignment of the limiting post 73 with the outer wall of the circuit board assembly 4 further enhances the compactness of the structure and reduces the volume occupied.

[0063] Alternatively, the limiting post 73 can also be configured as a flexible snap-fit, which facilitates installation and removal.

[0064] Please see Figure 6 In one embodiment, the rear end cover 12 includes a base portion 124 and a lug portion 125 provided at one end of the base portion 124. The base portion 124 is inserted into the rotating cavity 111 so that the lug portion 125 abuts against the opening 112 of the main body portion 11. A connecting surface 121 is formed on the side of the base portion 124 facing away from the rotating cavity 111.

[0065] In this embodiment, the rear end cover 12 includes a base portion 124 and a hook portion 125. The base portion 124 is inserted into the rotating cavity 111, and the hook portion 125 can just abut against the opening 112 of the main body portion 11, thereby ensuring that the rear end cover 12 can fit tightly against the housing 1. A connecting surface 121 is formed on the side of the base portion 124 facing away from the rotating cavity 111 for mounting the drive plate assembly 5.

[0066] Please see Figure 6 In one embodiment, a cable 51 is provided on the side of the drive board assembly 5 facing away from the connection surface 121. The cable 51 and the connector 6 are symmetrically arranged on both sides of the drive board assembly 5. The cable 51 is used to connect with other devices.

[0067] In this embodiment, the drive board assembly 5 is provided with a cable 51 on the side facing away from the connection surface 121 for connecting with other devices to realize the transmission of signals or power.

[0068] Understandably, the cable 51 and the connector 6 are symmetrically arranged on both sides of the drive board assembly 5, thereby optimizing the spatial layout, avoiding contact between the cable 51 and the connector 6, and ensuring the orderly flow of the circuit.

[0069] Please see Figure 2 and Figure 6 The hollow cup brushless motor 100 also includes a support ring 8 disposed on the connecting surface 121, and a second gap space 81 is formed between the support ring 8 and the connecting surface 121. The drive plate assembly 5 is limited to the support ring 8.

[0070] In this embodiment, the support ring 8 is disposed on the connecting surface 121, and the drive board assembly 5 is mounted on the support ring 8, so that a second gap space 81 is formed between the drive board assembly 5 and the connecting surface 121, thereby preventing the drive board assembly 5 from directly contacting the rear cover 12 and avoiding short circuit.

[0071] Please see Figure 3 and Figure 6 The circuit board assembly 4 is provided with a terminal frame 43, and the connector 6 is inserted into the terminal frame 43 to connect with the circuit board assembly 4.

[0072] In this embodiment, the terminal block 43 is used to fix the connector 6, ensuring a reliable connection between the connector 6 and the circuit board assembly 4. It is understood that leading out the steel pin through the terminal block 43 not only prevents the steel pin from tilting during installation, but also serves a positioning and insulation function.

[0073] Please see Figure 4 and Figure 5 In one embodiment, the circuit board assembly 4 is a Hall plate, which includes a substrate and a plurality of Hall sensors 42 disposed on the substrate. The plurality of Hall sensors 42 are located on the side of the substrate facing the rotor assembly 2 and are electrically connected to the substrate. The Hall sensors 42 are used to detect the rotation of the rotor assembly 2. The side of the substrate facing the rotor assembly 2 is electrically connected to the stator assembly 3, and the other side of the substrate is electrically connected to the drive board assembly 5 through the connector 6.

[0074] In this embodiment, when the circuit board assembly 4 is a Hall plate, the Hall plate includes a substrate and multiple Hall sensors 42. The Hall sensors 42 are located on the side of the substrate facing the rotor assembly 2 and are used to detect the rotation state of the rotor assembly 2. The other side of the substrate is electrically connected to the drive board assembly 5 through a connector 6 to realize signal transmission.

[0075] Understandably, eight steel pins can be used to connect the Hall plate and the drive board assembly 5. Three steel pins are used to transmit the current signal of the armature coil cup 32, and five steel pins are used to transmit the rotor rotation signal detected by the Hall sensor 42 and to provide power to the Hall sensor 42.

[0076] Please see Figure 3 In one embodiment, the circuit board assembly 4 is a terminal block, with the side of the terminal block facing the stator assembly 3 electrically connected to the stator assembly 3, and the other side of the terminal block electrically connected to the drive board assembly 5 via a connector 6.

[0077] In this embodiment, when the circuit board assembly 4 is a terminal block, the terminal block is used to realize the electrical connection between the stator assembly 3 and the drive board assembly 5. One side of the terminal block is electrically connected to the stator assembly 3, and the other side is electrically connected to the drive board assembly 5 through the connector 6.

[0078] Understandably, three steel pins can be used to connect the terminal block and the drive board assembly 5. The three steel pins are used to transmit the current signal of the armature coil cup 32.

[0079] The above description is merely an exemplary embodiment of the present utility model and does not limit the patent scope of the present utility model. Any equivalent structural transformations made based on the technical concept of the present utility model and the contents of the present utility model specification and drawings, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present utility model.

Claims

1. A hollow cup brushless motor, characterized in that, The hollow cup brushless motor includes: A housing, wherein the housing is provided with a rotating cavity and a connecting surface located on the outer side of the rotating cavity; A rotor assembly, wherein the rotor assembly is rotatably disposed within the rotating cavity; A stator assembly, disposed on the inner wall of the rotating cavity, is used to drive the rotor assembly to rotate; A circuit board assembly, wherein the circuit board assembly is disposed within the rotating cavity and electrically connected to the stator assembly; and A driver board assembly is disposed on the connecting surface and electrically connected to the circuit board assembly via a connector.

2. The hollow cup brushless motor as described in claim 1, characterized in that, The housing includes a main body and a rear end cover. The main body has the rotating cavity and an opening communicating with the rotating cavity. The rear end cover is disposed at the opening, and the side of the rear end cover facing away from the rotating cavity forms the connecting surface. The circuit board assembly is disposed between the stator assembly and the rear end cover, and a first gap space is provided between the circuit board assembly and the rear end cover.

3. The hollow cup brushless motor as described in claim 2, characterized in that, The hollow cup brushless motor also includes a bracket disposed on the inner wall of the rotating cavity. One side of the bracket abuts against the stator assembly, and the other side of the bracket forms a mounting surface. The circuit board assembly is confined to the mounting surface so that the first gap space is provided between the circuit board assembly and the rear end cover.

4. The hollow cup brushless motor as described in claim 3, characterized in that, The rear end cover has a notch that connects to the rotating cavity. The connector passes through the notch, and its two ends are connected to the circuit board assembly and the drive board assembly, respectively.

5. The hollow cup brushless motor as described in claim 4, characterized in that, The bracket is also provided with a limiting baffle, which corresponds to the notch.

6. The hollow cup brushless motor as described in claim 3, characterized in that, The bracket is provided with multiple limiting posts in the circumferential direction, and the circuit board assembly is provided with multiple limiting grooves in the circumferential direction, with each limiting post corresponding to a limiting groove. When the circuit board assembly is disposed on the mounting surface, the limiting post is inserted into the limiting groove and aligned with the outer wall of the circuit board assembly along the circumferential direction of the circuit board assembly.

7. The hollow cup brushless motor as described in claim 2, characterized in that, The rear end cover includes a base portion and a hanging ear portion disposed at one end of the base portion. The base portion is inserted into the rotating cavity so that the hanging ear portion abuts against the opening of the main body portion.

8. The hollow cup brushless motor as described in claim 1, characterized in that, The drive board assembly has a cable on the side facing away from the connection surface. The cable and the connector are symmetrically arranged on both sides of the drive board assembly. The cable is used to connect to other devices.

9. The hollow cup brushless motor as described in any one of claims 1 to 8, characterized in that, The circuit board assembly is a Hall plate, which includes a substrate and a plurality of Hall sensors disposed on the substrate. The plurality of Hall sensors are located on the side of the substrate facing the rotor assembly and are electrically connected to the substrate. The Hall sensors are used to detect the rotation of the rotor assembly. The side of the substrate facing the rotor assembly is electrically connected to the stator assembly, and the other side of the substrate is electrically connected to the drive board assembly through the connector.

10. The hollow cup brushless motor according to any one of claims 1 to 8, characterized in that, The circuit board assembly is a terminal block. The side of the terminal block facing the stator assembly is electrically connected to the stator assembly, and the other side of the terminal block is electrically connected to the drive board assembly through the connector.

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