Hollow cup motor and manufacturing method thereof

Abstract

The invention relates to a coreless motor and a coreless motor manufacturing method. The coreless motor manufacturing method comprises the following steps: S1, separately assembling a stator assembly and a rotor assembly; the stator assembly is provided with a power line; the rotor assembly is provided with a rotating shaft; s2, the rotor assembly and the stator assembly are assembled, the rotating shaft penetrates out of one end of the stator assembly, and meanwhile the power line is led out of the rotor assembly; s3, connecting the power line with the circuit board and leading out a power line; and S4, installing a reduction gearbox and connecting the reduction gearbox with the rotating shaft. According to the manufacturing method of the coreless motor, the manufacturing process is optimized, the assembling portability is improved, the performance and the reliability of the coreless motor are improved, and mass production is facilitated.

Description

Technical Field

[0001] This invention relates to the field of electric motors, and more particularly to a coreless motor and a method for manufacturing a coreless motor. Background Technology

[0002] Coreless motors are being widely used in high-precision robots, especially humanoid robots that have emerged in recent years, due to their advantages such as small size, high energy density, and ease of control. These robots not only require high-performance motors but also have compact structures.

[0003] In the past, the stator and rotor assemblies of coreless motors were usually not assembled independently. For example, the shaft and the second bearing were installed in place before the first bearing was pressed in. However, in the actual assembly process of micro motors, this installation method often resulted in the shaft being deformed due to the pressure of the end cover, which deteriorated the overall reliability and noise performance of the coreless motor. In addition, the assembly process was cumbersome and the possibility of mass production was low. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide an improved hollow cup motor and a method for manufacturing a hollow cup motor.

[0005] The technical solution adopted by this invention to solve its technical problem is: to construct a method for manufacturing a hollow cup motor, including the following steps: S1. Separately assemble the stator assembly and the rotor assembly; the stator assembly has a power line; the rotor assembly has a shaft. S2. Assemble the rotor assembly with the stator assembly, and pass the rotating shaft out from one end of the stator assembly, while simultaneously leading the power line out from the rotor assembly; S3. Connect the power line to the circuit board and lead out the power line: S4. Install the gearbox and connect it to the rotating shaft.

[0006] Preferably, in step S1, assembling the stator assembly includes the following steps: S1.1, Provides a housing, a first bearing, a sealing ring, a gasket, a stator core, and a hollow cup coil; the housing is hollow and has a first end and a second end in the axial direction; the housing has an opening at the second end; S1.1. Place the sealing ring on the first bearing, and then insert both of them into the first end of the housing through the opening; S1.2 Insert the gasket into the housing through the opening, close to the first bearing; S1.3. Install the stator core into the housing through the opening; S1.4 The hollow cup coil is installed inside the stator core through the opening, wherein the power line is led out from the hollow cup coil.

[0007] Preferably, in step S1, assembling the stator assembly further includes: S1.5, with one end cap provided; S1.6 Lead the power line out from the end cover and press the end cover into the second end of the housing.

[0008] Preferably, in step S1, assembling the rotor assembly includes: The system provides an induction magnet, a second bearing, a preload spring, a first counterweight, a magnet, a second counterweight, and the rotating shaft. The induction magnet, the second bearing, the preload spring, the first balance block, the magnet, and the second balance block are sequentially assembled on the rotating shaft along the axial direction of the rotating shaft to form the rotor assembly.

[0009] Preferably, in step S2, after the rotor assembly and the stator assembly are assembled, a bearing block with lead wire holes is provided, the power line is led out from the lead wire holes of the bearing block, and then the bearing block is pressed into the rotor assembly.

[0010] This invention relates to a coreless motor, which is manufactured using the coreless motor manufacturing method described in this invention, and includes a stator assembly and a rotor assembly; the rotor assembly is at least partially installed in the stator assembly.

[0011] Preferably, the stator assembly includes a housing, a first bearing, a sealing ring, a gasket, a stator core, and a hollow cup coil; The housing is hollow and has a first end and a second end in the axial direction; the housing has an opening at the second end. The first bearing is mounted on the first end; the sealing ring is disposed between the housing and the first bearing; The gasket is disposed in the housing and located at the end of the stator core facing the first bearing; The stator core is installed in the housing; the hollow cup coil is installed in the stator core; the hollow cup coil has a power line.

[0012] Preferably, the surface of the gasket is provided with a first insulating layer; And / or, the surface of the stator core is provided with a second insulating layer.

[0013] Preferably, the stator assembly further includes an end cap mounted on the second end, the end cap having a central hole.

[0014] Preferably, the rotor assembly includes an induction magnet, a second bearing, a preload spring, a first counterweight, a magnet, a second counterweight, and a rotating shaft; The induction magnet, the second bearing, the preload spring, the first balance block, the magnet, and the second balance block are sequentially sleeved on the rotating shaft along the axial direction of the rotating shaft; When the rotor assembly is assembled with the stator assembly, the second bearing is installed in the center hole and mates with the center hole. The hollow cup motor also includes a bearing block, which is sleeved on the outer periphery of the induction magnet and located on the side of the second bearing away from the first balance block.

[0015] The hollow cup motor and its manufacturing method of the present invention have the following beneficial effects: The manufacturing method of the hollow cup motor optimizes the manufacturing process, improves the portability of assembly, and enhances the performance and reliability of the hollow cup motor by assembling the stator assembly and the rotor assembly separately, assembling the stator assembly and the rotor assembly, leading out the power lines of the stator assembly and connecting them to the circuit board, and finally installing the gearbox and connecting it to the shaft of the rotor assembly. Attached Figure Description

[0016] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings: Figure 1 These are schematic diagrams of the hollow cup motor in some embodiments of the present invention; Figure 2 This is the present invention. Figure 1 A schematic diagram of a partial structure of the rotor assembly of a hollow cup motor is shown. Figure 3 This is the present invention. Figure 1 The diagram shows the stator assembly structure of the hollow cup motor. Figure 4 This is a flowchart of the manufacturing process of the hollow cup motor of the present invention. Detailed Implementation

[0017] To provide a clearer understanding of the technical features, objectives, and effects of the present invention, specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings. In the following description, it should be understood that the terms "upper," "top," "bottom," "inner," "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are constructed and operated in a specific orientation. They are only for the convenience of describing the technical solution and do not indicate that the device or element referred to must have a specific orientation; therefore, they should not be construed as limitations on the present invention.

[0018] It should also be noted that, unless otherwise explicitly specified and limited, terms such as "installation," "connection," "linking," "fixing," and "setting" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. When an component is referred to as being "on" or "below" another component, the component can be located "directly" or "indirectly" on the other component, or there may be one or more intermediary components. The terms "first," "second," etc., are only for the convenience of describing this technical solution and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. For those skilled in the art, the specific meaning of the above terms in this invention can be understood according to the specific circumstances.

[0019] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of the invention. However, those skilled in the art will understand that the invention can be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods are omitted so as not to obscure the description of the invention with unnecessary detail.

[0020] Figure 1 Some preferred embodiments of the hollow cup motor of the present invention are shown. This hollow cup motor can serve as a power output mechanism for outputting power. The hollow cup motor has the advantages of compact structure, high power density, and high reliability.

[0021] like Figures 1 to 3 As shown, the hollow cup motor may include a stator assembly 10 and a rotor assembly 20. The rotor assembly 20 may be at least partially installed in the stator assembly 10. The stator assembly 10 and the rotor assembly 20 can cooperate with each other to achieve power output when energized. The stator assembly 10 and the rotor assembly 20 are independent structures and can be manufactured separately.

[0022] like Figure 1 and Figure 2 As shown, in some embodiments, the stator assembly 10 may include a housing 11, a first bearing 12, a sealing ring 13, a gasket 14, a stator core 15, and a hollow cup coil 16. The first bearing 12, the sealing ring 13, the gasket 14, the stator core 15, and the hollow cup coil 16 may be sequentially installed into the housing 11.

[0023] In some embodiments, the housing 11 may be a hollow structure extending through both ends. The housing 11 may be a columnar structure. The housing 11 has a first end 11a and a second end 11b in the axial direction, and the first end 11a and the second end 11b may be through-connected. The housing 11 may include a main body 111 and a connecting portion 112. The main body 111 is a columnar structure, and the connecting portion 112 is disposed at one end of the main body 111 and coaxially arranged with the main body 111. The cross-sectional dimension of the connecting portion 112 may be smaller than the cross-sectional dimension of the main body 111. The connecting portion 112 can be used to connect with the gearbox 60. The first end 11a is formed at the end of the connecting portion 112 away from the main body 111. The second end 11b is formed at the end of the main body 111 away from the connecting portion 112. The housing 11 has an opening 1111 at the second end 11b, which can be used for mounting various components into the housing 11.

[0024] In some embodiments, the first bearing 12 is mounted on the first end. Specifically, the first bearing 12 can be inserted into the connecting portion 112 through the opening 1111 and is coaxially arranged with the connecting portion 112.

[0025] In some embodiments, the sealing ring 13 is disposed between the housing 11 and the first bearing 12. Specifically, it can be sleeved on the outer periphery of the first bearing 12 and can be interference-fitted with the first bearing 12. In some embodiments, a limiting groove 1121 can be provided on the inner sidewall of the connecting portion 112, and the sealing ring 13 can be embedded in the limiting groove 1121.

[0026] In some embodiments, the gasket 14 is disposed in the housing 11 and located at the end of the stator core 15 facing the first bearing 12. The gasket 14 may be annular, may be a PVC gasket, and may be coaxially disposed with the housing 11. A first insulating layer may be disposed on the surface of the gasket 14. This first insulating layer may be a polymer nanomaterial, which may be coated or electroplated onto the surface of the gasket 14. Specifically, the first insulating layer may be disposed on two opposing surfaces of the gasket 14, one of which may face the first bearing 12. By providing the first insulating layer, the insulation of the gasket 14 can be increased, and the utilization rate of the electromagnetic space inside the motor can be increased, thereby improving the overall power density of the motor.

[0027] In some embodiments, the stator core 15 can be a through-type structure, which can be inserted into the housing 11 through the opening 1111 and is coaxially arranged with the housing 11. A second insulating layer is provided on the surface of the stator core 15, which can be disposed on the inner and outer surfaces of the stator core 15. In some embodiments, the second insulating layer can be a polymer nanomaterial, which can be coated or electroplated on the surface of the stator core 15. By providing the second insulating layer, the insulation of the stator core 15 can be increased, and the utilization rate of the electromagnetic space inside the motor can be increased, thereby improving the overall power density of the motor.

[0028] In some embodiments, the hollow cup coil 16 is mounted in the stator core 15 and can be coaxially arranged with the stator core 15. The stator assembly 10 has a power line, specifically, the hollow cup coil 16 has the power line, which can be led out of the housing 11.

[0029] In some embodiments, the stator assembly 10 further includes an end cap 17, which can be mounted on the second end 11b, specifically, it can be partially inserted into the housing 11 from the opening 1111. The end cap 17 has a central hole 171, which can be coaxially arranged with the housing 11. In some embodiments, the end cap 17 can be fixed to the housing 11 by an interference fit.

[0030] like Figure 1 and Figure 3 As shown, in some embodiments, the rotor assembly 20 may include an induction magnet 22, a second bearing 23, a preload spring 24, a first balance block 25, a magnet 26, a second balance block 27, and a rotating shaft 21. The induction magnet 22, second bearing 23, preload spring 24, first balance block 25, magnet 26, and second balance block 27 are sequentially sleeved on the rotating shaft 21 along its axial direction. Specifically, the rotating shaft 21 may be cylindrical and longitudinally elongated; in some embodiments, the rotating shaft 21 may be cylindrical. The induction magnet 22 may be annular and flush with the end of the rotating shaft 21, and may be interference-fitted with the rotating shaft 21. The outer diameter of the second bearing 23 may be adapted to the inner radial direction of the center hole 171 of the end cover 17, and its outer diameter may be larger than the outer diameters of the induction magnet 22 and the first balance block 25. The preload spring 24 is disposed between the second bearing 23 and the first balance block 25, and may abut against the second bearing 23 and the first balance block 25. Both the first balancing block 25 and the second balancing block 27 can be ring-shaped, and they are located at the two ends of the magnet 26, respectively.

[0031] In some embodiments, the hollow cup motor further includes a bearing clamping block 30, which is embedded in the end cover 17 and sleeved on the outer periphery of the induction magnet 22. The bearing clamping block 30 is located on the side of the second bearing 23 away from the first balance block 25, and can press the second bearing 23 in place. In some embodiments, the bearing clamping block 30 has a lead wire hole, which can be used for the power line of the stator assembly 10 to be led out. In some embodiments, the bearing clamping block 30 can be a plastic part.

[0032] In some embodiments, the hollow cup motor further includes a circuit board 40, which may be disposed on the side of the end cover 17 facing away from the connection portion 112. The power line of the hollow cup coil 16 may be connected to the circuit board 40. The circuit board 40 may be connected to a power line, and the power line may be led out to the outside of the motor to be connected to an external power source.

[0033] In some embodiments, the hollow cup motor further includes a cover 50, which is detachably mounted on the end cover 17, and the circuit board 40 may be disposed between the cover 50 and the end cover 17. In some embodiments, a power cord may be led out from the cover 50 to the outside.

[0034] In some embodiments, the coreless motor further includes a gearbox 60, which is mounted on the connecting portion 112 of the housing 11 and connected to the rotating shaft 21. In some embodiments, the gearbox 60 may be sleeved on the connecting portion 112 and may be threadedly connected to the connecting portion 112.

[0035] Figure 4 The invention illustrates a method for manufacturing a hollow cup motor. This method is simple and portable to operate, and can improve the performance and reliability of the hollow cup motor, which is beneficial for the mass production of hollow cup motors.

[0036] like Figure 4 As shown, the manufacturing method of this hollow cup motor includes the following steps: S1. The stator assembly 10 and the rotor assembly 20 are assembled separately; the stator assembly 10 has a power line; the rotor assembly 20 has a rotating shaft 21.

[0037] It should be noted that assembling the stator assembly 10 and the rotor assembly 20 separately can improve the mass production performance of the coreless motor, avoid the bending and deformation of the shaft 21 which would reduce the reliability of the assembly, and the rotor assembly does not need to wait for the end cover 17 to be pressed in before installing the induction magnet 22, thus avoiding the pressure on the shaft 21 when installing the induction magnet 22.

[0038] Specifically, assembling the stator assembly 10 may include the following steps: S1.1 A housing 11, a first bearing 12, a sealing ring 13, a gasket 14, a stator core 15, and a hollow cup coil 16 are provided. The housing 11 is hollow and has a first end 11a and a second end 11b in the axial direction. The housing 11 has an opening 1111 at the second end 11b. In some embodiments, the surface of the gasket 14 is provided with a first insulating layer. In some embodiments, the surface of the stator core 15 is provided with a second insulating layer. Both the first and second insulating layers can be layers of polymer nanomaterials.

[0039] S1.1. The sealing ring 13 is fitted onto the first bearing 12, and then both are inserted into the first end 11a of the housing 11 through the opening 1111. The sealing ring 13 can be a silicone ring, which can be fitted onto the first bearing 12 and can be interference-fitted with the first bearing 12. The sealing ring 13 and the first bearing 12 are inserted into the connecting part 112 of the housing 11 through the opening 1111, and the sealing ring 13 can be inserted into the limiting groove 1121.

[0040] S1.2 Insert the gasket 14 into the housing 11 through the opening 1111, and place it close to the first bearing 12. Specifically, the gasket 14 can be installed along the axial direction of the housing 11 between the connecting part 112 and the main body 111, and close to the end wall where the main body 111 and the connecting part 112 meet.

[0041] S1.3 Install the stator core 15 into the housing 11 through the opening 1111. Specifically, the stator core 15 is inserted into the main body 111 through the opening 1111 along the axial direction of the housing 11, with one end abutting against the gasket 14.

[0042] S1.4. The hollow cup coil 16 is installed inside the stator core 15 through the opening 1111, with the power line leading out from the hollow cup coil 16. Specifically, the hollow cup coil 16 can be installed into the stator core 15 along the axial direction of the housing 11, and is coaxially arranged with the stator core 15, and can be close to the inner wall of the stator core 15, and then the power line is led out from the opening 1111.

[0043] In step S1, assembling the stator assembly also includes: S1.5, an end cap 17 is provided; wherein the end cap 17 has a central hole 171. In some embodiments, a wire through hole may also be provided on the end cap 17 for the power line to pass through. In some embodiments, the wire through hole may be omitted.

[0044] S1.6 Lead the power line out from the end cover 17 and press the end cover 17 into the second end 11b of the housing 11. Lead the power line out from the wire hole or center hole 171 of the end cover 17, and then insert the end cover 17 into the opening 1111 to cover the opening 1111.

[0045] In some embodiments, assembling the rotor assembly 20 may include: It provides an induction magnet 22, a second bearing 23, a preload spring 24, a first balance block 25, a magnet 26, a second balance block 27, and a rotating shaft 21; The induction magnet 22, the second bearing 23, the preload spring 24, the first balance block 25, the magnet 26, and the second balance block 27 are sequentially assembled onto the rotating shaft 21 along its axial direction to form a rotor assembly. Specifically, the induction magnet 22, the second bearing 23, the preload spring 24, the first balance block 25, the magnet 26, and the second balance block 27 can be sequentially sleeved onto the rotating shaft 21, wherein one end of the preload spring 24 can abut against the second bearing 23, and the other end can abut against the first balance block 25.

[0046] It should be noted that this coreless motor eliminates the traditional encoder magnet bushing. The rotating shaft 21 and the induction magnet 22 are pre-installed during the manufacturing process, thus eliminating the risk of glue flowing into the bearing.

[0047] S2. Assemble the rotor assembly 20 with the stator assembly 10, and pass the rotating shaft 21 out from one end of the stator assembly 10, while leading the power line out from the rotor assembly 20.

[0048] Specifically, the rotor assembly 20 can be inserted into the hollow cup coil 16 along the axial direction of the stator assembly 10, and the rotor shaft of the rotor assembly 20 passes through the first bearing 12 and the connecting part 112 in sequence. The second bearing 22 of the rotor assembly 20 can be placed in the central hole 171 of the end cover 17, and the power line can be led out from one side of the rotor assembly 20.

[0049] After the rotor assembly 20 is assembled with the stator assembly 10, a bearing clamp 30 with lead wire holes is provided, and the power line is led out from the lead wire holes of the bearing clamp 30 before the bearing clamp 30 is pressed into the rotor assembly 10.

[0050] Specifically, the power line can be led out from the lead hole of the bearing block 30 to the outside, and the bearing block 30 can be partially embedded in the end cover 17 and fitted into the outer periphery of the induction magnet 22 of the rotor assembly 20, and coaxially arranged with the induction magnet 22.

[0051] It should be noted that by using a bearing clamp 30 to replace the traditional bearing chamber with a bearing stop, the problems of poor insulation and withstand voltage of the power line and eddy current loss generated by traditional metal materials during the rotation of the induction magnet 22 are avoided. This solves the problem of the power line being suspended behind the end cover 17 and avoids the problem of the power line scraping against the induction magnet 22 and causing wire breakage.

[0052] S3. Connect the power line to the circuit board 40 and lead out the power line. Specifically, the power line can be soldered to the circuit board 40, then the circuit board 40 can be connected to the power line, and the power line can be led out from the cover 50. Finally, the cover 50 and the end cover 17 can be assembled.

[0053] S4. Install the gearbox 60 and connect it to the rotating shaft 21. Specifically, the gearbox 60 can be installed on the connecting part 112 of the housing 11 and screwed to the connecting part 112 of the housing 11, and connected to the rotating shaft 21.

[0054] It is understood that the above embodiments only illustrate preferred embodiments of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can freely combine the above technical features without departing from the concept of the present invention, and can also make several modifications and improvements, all of which fall within the protection scope of the present invention. Therefore, all equivalent transformations and modifications made with respect to the scope of the claims of the present invention should fall within the scope of the claims of the present invention.

Claims

1. A method for manufacturing a hollow cup motor, characterized in that, Includes the following steps: S1. Separately assemble the stator assembly (10) and the rotor assembly (20); the stator assembly (10) has a power line; the rotor assembly (20) has a shaft (21). S2. Assemble the rotor assembly (20) with the stator assembly (10), and pass the shaft (21) through one end of the stator assembly (10), while leading the power line out from the rotor assembly (20); S3. Connect the power line to the circuit board (40) and lead out the power line: S4. Install the gearbox (60) and connect it to the shaft (21).

2. The method for manufacturing a hollow cup motor according to claim 1, characterized in that, In step S1, assembling the stator assembly (10) includes the following steps: S1.1 Provide a housing (11), a first bearing (12), a sealing ring (13), a gasket (14), a stator core (15), and a hollow cup coil (16); the housing (11) is hollow and has a first end (11a) and a second end (11b) in the axial direction; the housing (11) has an opening (1111) at the second end (11b). S1.

1. Place the sealing ring (13) on the first bearing (12) and then insert both of them into the first end (11a) of the housing (11) through the opening (1111). S1.2 Insert the gasket (14) into the housing (11) through the opening (1111) and close to the first bearing (12). S1.3 Install the stator core (15) into the housing (11) through the opening (1111); S1.4 The hollow cup coil (16) is installed inside the stator core (15) through the opening (1111), wherein the power line is led out from the hollow cup coil (16).

3. The method for manufacturing a hollow cup motor according to claim 1, characterized in that, In step S1, assembling the stator assembly (10) further includes: S1.5, provides an end cap (17); S1.6 Lead the power line out from the end cover (17) and press the end cover (17) into the second end (11b) of the housing (11).

4. The method for manufacturing a hollow cup motor according to claim 1, characterized in that, In step S1, assembling the rotor assembly (20) includes: Provided are an induction magnet (22), a second bearing (23), a preload spring (24), a first balance block (25), a magnet (26), a second balance block (27), and the rotating shaft (21); The induction magnet (22), the second bearing (23), the preload spring (24), the first balance block (25), the magnet (26), and the second balance block (27) are sequentially assembled on the rotating shaft (21) along the axial direction of the rotating shaft (21) to form the rotor assembly (20).

5. The method for manufacturing a hollow cup motor according to claim 1, characterized in that, In step S2, after the rotor assembly (20) is assembled with the stator assembly (10), a bearing block (30) with lead wire holes is provided, the power line is led out from the lead wire holes of the bearing block (30), and the bearing block (30) is pressed into the rotor assembly (20).

6. A hollow cup motor, manufactured using the hollow cup motor manufacturing method according to any one of claims 1 to 5, characterized in that, It includes a stator assembly (10) and a rotor assembly (20); the rotor assembly (20) is at least partially mounted in the stator assembly (10).

7. The hollow cup motor according to claim 6, characterized in that, The stator assembly (10) includes a housing (11), a first bearing (12), a sealing ring (13), a gasket (14), a stator core (15), and a hollow cup coil (16). The housing (11) is hollow and has a first end (11a) and a second end (11b) in the axial direction; the housing (11) has an opening (1111) at the second end (11b). The first bearing (12) is mounted on the first end (11a); the sealing ring (13) is disposed between the housing (11) and the first bearing (12); The gasket (14) is disposed in the housing (11) and located at the end of the stator core (15) facing the first bearing (12); The stator core (15) is installed in the housing (11); the hollow cup coil (16) is installed in the stator core (15); the hollow cup coil (16) has a power line.

8. The hollow cup motor according to claim 7, characterized in that, The surface of the gasket (14) is provided with a first insulating layer; And / or, the surface of the stator core (15) is provided with a second insulating layer.

9. The hollow cup motor according to claim 7, characterized in that, The stator assembly (10) further includes an end cap (17) mounted on the second end (11b) and having a central hole (171).

10. The hollow cup motor according to claim 9, characterized in that, The rotor assembly (20) includes an induction magnet (22), a second bearing (23), a preload spring (24), a first counterweight (25), a magnet (26), a second counterweight (27), and a rotating shaft (21). The induction magnet (22), the second bearing (23), the preload spring (24), the first balance block (25), the magnet (26), and the second balance block (27) are sequentially sleeved on the rotating shaft (21) along the axial direction of the rotating shaft (21); When the rotor assembly (20) is assembled with the stator assembly (10), the second bearing (23) is installed in the center hole (171) and cooperates with the center hole (171); The hollow cup motor also includes a bearing block (30), which is sleeved on the outer periphery of the induction magnet (22) and located on the side of the second bearing (23) away from the first balance block (25).

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