An adaptive weak magnetic disk motor

Abstract

The present invention relates to the field of motors, and specifically to an adaptive weak magnetic disk motor. An adaptive weak magnetic disk motor comprises: a stator; a rotor, wherein the rotor comprises a rotor support and a guide magnetic disk, wherein the guide magnetic disk is assembled on the rotor support in a rotational manner, wherein the guide magnetic disk can slide axially relative to the rotor support, wherein permanent magnets are distributed on the end surface of the guide magnetic disk opposite to the stator, wherein a cavity with an axial depth decreasing radially is formed between the rotor support and the guide magnetic disk; and a centrifugal part, wherein the centrifugal part is accommodated in the cavity, wherein the centrifugal part moves radially outward under the centrifugal action to push the guide magnetic disk axially away from the stator. The invention solves the technical problems in the prior art that the motor needs to apply a weak magnetic current to perform weak magnetic control, which is inefficient, and improper control can easily cause demagnetization of the permanent magnet.

Description

Technical Field

[0001] The invention relates to the field of motors, and in particular to an adaptive weak-disk magnetic disk type motor. Background Art

[0002] The current penetration rate of electric bicycles is already very high, but electric motorcycles are rare. This is because vehicles using hub motors usually do not have a very high speed, usually 60 to 70 kilometers is the limit, while electric motorcycles generally require a speed of more than 100 kilometers, so a mid-mounted motor is inevitable. The mid-mounted motor drives the rear wheel of the motorcycle to rotate through a belt or chain, and generally does not use a gearbox. This requires the motor to have a wider high-efficiency range, with torque at low speeds and high-speed operation.

[0003] Usually, the existing technology designs motors with high salient pole ratios and adopts weak magnetic field control of the controller to increase the speed regulation range of the motor. This method can certainly meet the requirements, but it actually has some disadvantages: 1. Weak magnetic field control requires the application of weak magnetic field current to the motor, which will reduce the motor efficiency to a certain extent. Improper control of weak magnetic field current will also cause permanent demagnetization of the motor's permanent magnet; 2. Motors with high salient pole ratios usually have low torque density. In order to achieve the torque required by the design, a larger volume and manufacturing cost are usually required; 3. Weak magnetic field control requires the use of high-precision position sensors, usually encoders or rotary transformers, which is not conducive to cost control. Summary of the invention

[0004] In order to solve the technical problems in the prior art that the motor needs to apply a weak magnetic current to perform weak magnetic control, which is inefficient and can easily cause permanent magnet demagnetization due to improper control, the present invention proposes an adaptive weak magnetic disk motor to solve the above technical problems. The technical solution of the present invention is as follows:

[0005] An adaptive weak magnetic disk type motor comprises: a stator; a rotor, wherein the rotor comprises a rotor support and a guide magnetic disk, wherein the guide magnetic disk is assembled on the rotor support in a rotationally manner, wherein the guide magnetic disk can slide axially relative to the rotor support, wherein permanent magnets are distributed on the end surface of the guide magnetic disk opposite to the stator, wherein a cavity with an axial depth decreasing radially is formed between the rotor support and the guide magnetic disk; and a centrifugal member, wherein the centrifugal member is accommodated in the cavity, wherein the centrifugal member moves radially outward under the centrifugal action to push the guide magnetic disk axially away from the stator.

[0006] The adaptive weak magnetic disk motor of the present application is provided with a cavity whose axial depth decreases radially between the rotor support and the guide magnetic disk of the rotor, and the cavity contains the centrifugal part. When the rotor rotates at high speed, the centrifugal part moves radially outward in the cavity under the centrifugal action, pushing the guide magnetic disk axially away from the stator, and the air gap length between the permanent magnet on the guide magnetic disk and the stator increases, thereby weakening the magnetic field strength, and further improving the weak magnetic speed regulation performance of the motor under high-speed operation. The adaptive weak magnetic disk motor of the present application utilizes the characteristics of the disk motor and cleverly utilizes the centrifugal force when the motor rotates to adjust the air gap length of the motor to achieve the purpose of controlling the magnetic field strength, thereby greatly increasing the speed regulation range of the motor. Since the motor structure itself adopts the surface-mounted magnet with the highest torque density, the motor has both the highest low-speed torque and an ultra-large speed regulation range, and does not require the addition of weak magnetic current, so the risk of motor magnet demagnetization is greatly reduced and the efficiency is significantly improved.

[0007] According to an embodiment of the present invention, an elastic member is provided between the rotor bracket and the guide disk.

[0008] According to one embodiment of the present invention, the guide disk includes a radially distributed mounting portion and a working portion, the mounting portion is movably connected to the rotor bracket, the working portion is axially close to the stator relative to the mounting portion, and the permanent magnet is attached to the end surface of the working portion opposite to the stator.

[0009] According to an embodiment of the present invention, the guide disk is assembled on the rotor bracket by a fixing member, and the fixing member is arranged parallel to the axis.

[0010] According to an embodiment of the present invention, the elastic member is sleeved on the fixing member, and two ends of the elastic member act on the rotor bracket and the guide disk respectively. In a stationary state, the elastic member is in a compressed state under the action of the magnetic attraction force.

[0011] According to an embodiment of the present invention, a first recess is formed on the rotor support, and a second recess is formed on the guide disk. The first recess and the second recess are opened relative to each other to form a cavity for accommodating the centrifugal member.

[0012] According to one embodiment of the present invention, there are at least two cavities, and the at least two cavities are evenly distributed along the circumferential direction.

[0013] According to one embodiment of the present invention, a counterweight is connected to the centrifugal member.

[0014] According to an embodiment of the present invention, the counterweight is hinged to the centrifugal member, and the counterweight and the centrifugal member slide radially together.

[0015] According to an embodiment of the present invention, a radial opening is formed on the rotor, and the counterweight passes through the radial opening and slides along the radial opening.

[0016] Based on the above technical solution, the technical effects that can be achieved by the present invention are:

[0017] 1. The adaptive weak magnetic disk type motor of the present invention has a cavity with an axial depth that decreases radially between the rotor support and the guide magnetic disk of the rotor, and the cavity accommodates a centrifugal part. When the rotor rotates at high speed, the centrifugal part moves radially outward in the cavity under the centrifugal effect, pushing the guide magnetic disk axially away from the stator, and the air gap length between the permanent magnet on the guide magnetic disk and the stator increases, thereby weakening the magnetic field strength, and further improving the weak magnetic speed regulation performance of the motor under high-speed operation. The adaptive weak magnetic disk type motor of the present application utilizes the characteristics of the disk motor and cleverly utilizes the centrifugal force when the motor rotates to adjust the air gap length of the motor to achieve the purpose of controlling the magnetic field strength, thereby greatly increasing the speed regulation range of the motor. Since the motor structure itself adopts the surface-mounted magnet with the highest torque density, the motor has both the highest low-speed torque and an ultra-large speed regulation range, and does not require the addition of weak magnetic current, so the risk of motor magnet demagnetization is greatly reduced and the efficiency is significantly improved;

[0018] 2. In the adaptive weak magnetic disk motor of the present invention, an elastic member is arranged between the rotor bracket and the guide magnetic disk to reduce the required centrifugal thrust: in the static state, the elastic member is in a compressed state, and the elastic member applies a maximum thrust to the guide magnetic disk. At this time, the magnetic attraction between the rotor and the stator is greater than the thrust of the elastic member, so the guide magnetic disk is still in a static state; when the motor starts to run, the thrust generated by the centrifugal force begins to increase. When the combined force of the thrust generated by the centrifugal force and the thrust of the elastic member is greater than the magnetic attraction, the guide magnetic disk begins to move axially away from the rotor bracket. As the speed increases, the distance becomes farther and farther, and finally the elastic member is in a natural state, where only the thrust generated by the centrifugal force and the magnetic attraction confront each other, and finally the maximum speed is reached; when the motor decelerates, the thrust generated by the centrifugal force is not enough to counter the magnetic attraction, and the guide magnetic disk moves axially close to the rotor bracket. At this time, the combined force of the thrust generated by the elastic member and the centrifugal force and the magnetic attraction confront each other, until the speed drops to zero, the centrifugal force disappears, and at this time the magnetic attraction is greater than the thrust of the elastic member, and the guide magnetic disk returns to its original position;

[0019] 3. In the adaptive weak magnetic disk type motor of the present invention, a counterweight is arranged on the centrifugal part. The weight of the centrifugal part can be increased by setting the counterweight, and the volume of the centrifugal part can be appropriately reduced, thereby reducing the volume of the entire motor; the counterweight slides through the radial opening, which can limit the movement direction of the counterweight and the centrifugal part. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1A three-dimensional diagram of the adaptive weak magnetic disk motor of the present invention;

[0021] Figure 2 This is the front view of the adaptive weak magnetic disk motor;

[0022] Figure 3 for Figure 2 AA section view;

[0023] Figure 4 It is a structural schematic diagram of the adaptive weak magnetic disk motor after removing the outer shell;

[0024] Figure 5 The cross-sectional view of the adaptive weak magnetic disk motor after removing the outer shell;

[0025] Figure 6 It is a structural schematic diagram of the adaptive weak magnetic disk type motor after removing the outer shell and the guide magnetic disk;

[0026] Figure 7 for Figure 6 A magnified view of part B;

[0027] Figure 8 is a schematic diagram of the structure of the rotor bracket;

[0028] In the figure: 1-stator; 2-rotor; 21-rotor bracket; 211-first recess; 212-accommodating hole; 213-first opening; 214-mounting hole; 22-guide disk; 23-permanent magnet; 3-centrifugal member; 4-elastic member; 5-fixing member; 6-counterweight member; 61-connecting structure; 7-rotating shaft; 8-housing. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0031] Unless otherwise specifically stated, the relative arrangement of the parts and steps described in these embodiments, numerical expressions and numerical values ​​do not limit the scope of the present invention. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, method and equipment known to ordinary technicians in the relevant field may not be discussed in detail, but in appropriate cases, the technology, method and equipment should be regarded as a part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0032] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the devices or elements referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention. The directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0033] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0034] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0035] like Figure 1-8As shown, this embodiment provides an adaptive weak magnetic disk motor, including a stator 1 and a rotor 2, both of which are disk-shaped, the stator 1 is fixedly assembled, the rotor 2 is rotatably assembled, and the permanent magnets 23 on the stator 1 and the rotor 2 are matched in axial clearance. A centrifugal part 3 is arranged in the rotor 2. When the motor is running at high speed, the centrifugal part 3 moves radially outward under the centrifugal action, pushing the permanent magnets 23 on the rotor 2 axially away from the stator 1, increasing the air gap length between the stator 1 and the rotor 2, realizing weak magnetic control of the motor at high speed, and having an ultra-large range of speed regulation. This adjustment process does not require manual operation, nor does it require the addition of a drive structure, nor does it require the addition of weak magnetic current. Automatic adjustment can be achieved by cleverly utilizing the centrifugal force when the motor rotates.

[0036] The stator 1 and the rotor 2 are both arranged in a housing 8, and a rotating shaft 7 is rotatably mounted in the housing 8. The stator 1 rotates on the rotating shaft 7 through a bearing. To prevent the stator 1 from rotating with the rotating shaft 7, the outer periphery of the stator 1 can be connected to the inner wall of the housing 8. The rotor 2 is mounted on the rotating shaft 7 and rotates with the rotating shaft 7. The rotor 2 includes a rotor support 21 and a guide magnetic disk 22 arranged thereon. A plurality of permanent magnets 23 are distributed on the end surface of the guide magnetic disk 22 opposite to the stator 1, and the axial clearance between the permanent magnet 23 and the stator 1 is matched. Specifically, the rotor support 21 is fixedly mounted on the rotating shaft 7, and the guide magnetic disk 22 is rotatably mounted on the rotor support 21. The guide magnetic disk 22 can slide axially relative to the rotor support 21, and the permanent magnet 23 is attached to the guide magnetic disk 22.

[0037] As a preferred technical solution of this embodiment, a mounting hole 214 is opened in the middle of the rotor bracket 21, and the rotating shaft 7 passes through the mounting hole 214 to achieve the fixed assembly of the rotor bracket 21 on the rotating shaft 7. Preferably, the mounting hole 214 can be extended to provide a limiting groove, and the shape of the rotating shaft 7 is adapted to the shape of the mounting hole 214 and the limiting groove to prevent relative deflection between the rotating shaft 7 and the rotor bracket 21.

[0038] As a preferred technical solution of this embodiment, the guide magnetic disk 22 includes a radially distributed mounting portion and a working portion, the mounting portion and the working portion are connected as a whole through a connecting portion, the mounting portion is used to connect with the rotor bracket 21, the connecting portion extends axially, the working portion is closer to the stator 1 than the mounting portion, and a permanent magnet 23 is distributed on the end surface of the working portion opposite to the stator 1. The guide magnetic disk 22 is limitedly assembled on the rotor bracket 21 by the fixing member 5.

[0039] As a preferred technical solution of this embodiment, the mounting portion is connected to the rotor bracket 21 through a fixing member 5. The fixing members 5 may be at least two and are arranged parallel to the axis. The ends of at least two fixing members 5 are fixed on the rotor bracket 21. The guide magnetic disk 22 is sleeved on the rotating shaft 7. The mounting portion of the guide magnetic disk 22 passes through the fixing member 5. The guide magnetic disk 22 can slide axially along the fixing member 5.

[0040] In order to adaptively change the axial gap between the guide disk 22 and the stator 1, the centrifugal member 3 is arranged between the rotor support 21 and the guide disk 22. The centrifugal member 3 can push the guide disk 22 to move axially under the action of centrifugal force, so as to drive the permanent magnet 23 thereon to axially move away from the stator 1, thereby increasing the air gap length between the stator 1 and the rotor 2, and realizing weak magnetic control at high speed. Specifically, a first recess 211 is arranged on the end surface of the rotor support 21 opposite to the mounting portion of the guide disk 22, and a second recess is arranged on the end surface of the mounting portion of the guide disk 22 opposite to the rotor support 21. The first recess 211 and the second recess openings relatively form a cavity for accommodating the centrifugal member 3, the cavity extends radially, and the axial depth of the cavity gradually decreases radially outward. In this embodiment, the axial depth of the first recess 211 gradually decreases radially outward, the axial depth of the second recess is constant, and the first recess 211 and the second recess opening are connected to form a cavity whose axial depth gradually decreases radially outward. In addition, the first recess 211 and the second recess may be set to other shapes, as long as the axial depth of the cavity gradually decreases radially outward. By setting the above cavity shape, when the centrifugal member 3 is placed in the cavity and moves radially outward under the action of centrifugal force, the centrifugal member 3 moves to a position where the axial depth of the cavity is smaller, and the guide disk 22 can be pushed axially away from the stator 1.

[0041] As a preferred technical solution of this embodiment, the centrifugal member 3 includes two coaxially connected centrifugal rollers, so that the centrifugal member 3 can roll in the cavity to reduce the friction between the centrifugal member 3 and the inner wall of the cavity.

[0042] In order to ensure the axial thrust of the centrifugal member 3 on the guide disk 22, the centrifugal member 3 is connected with a counterweight 6 to increase the mass of the centrifugal member 3. The size and mass of the centrifugal member 3 can be appropriately reduced, thereby reducing the size of the rotor 2 and preventing the motor from being too large. The counterweight 6 is connected to the centrifugal member 3 through a connecting structure 61. Specifically, one end of the connecting structure 61 is connected to the counterweight 6, and the other end of the connecting structure 61 is hinged to the centrifugal member 3. The counterweight 6 and the centrifugal member 3 slide radially together. Preferably, the connecting structure 61 is hinged to the connecting shaft between the two centrifugal rollers of the centrifugal member 3. Preferably, a radial opening is opened on the rotor 2. Specifically, a first opening 213 is opened on the rotor support 21, and a second opening is correspondingly opened on the guide disk 22. The first opening 213 and the second opening are correspondingly connected to form a radial opening. The counterweight 6 passes through the radial opening and can slide back and forth along the radial opening. The setting of the radial opening can limit the sliding direction of the counterweight 6.

[0043] As a preferred technical solution of this embodiment, an elastic member 4 is further provided between the rotor support 21 and the guide magnetic disk 22. In this embodiment, the elastic member 4 is sleeved on the fixing member 5 and is located between the rotor support 21 and the guide magnetic disk 22, and the two ends of the elastic member 4 act on the rotor support 21 and the guide magnetic disk 22 respectively. Preferably, the two ends of the elastic member 4 are connected to the rotor support 21 and the guide magnetic disk 22 respectively. In the static state, the elastic member 4 is in a compressed state, and the elastic member 4 applies a maximum thrust to the guide disk 22. At this time, the magnetic attraction between the rotor 2 and the stator 1 is greater than the thrust of the elastic member 4, so the guide disk 22 is still in a static state; when the motor starts to run, the thrust generated by the centrifugal force begins to increase. When the thrust generated by the centrifugal force and the thrust of the elastic member 4 are greater than the magnetic attraction, the guide disk 22 begins to move axially away from the rotor bracket 21. As the speed increases, the distance becomes farther and farther, and finally the elastic member 4 is in a natural state, and only the thrust generated by the centrifugal force and the magnetic attraction are in opposition, and finally the maximum speed is reached; when the motor decelerates, the thrust generated by the centrifugal force is not enough to resist the magnetic attraction, and the guide disk 22 moves axially close to the rotor bracket 21. At this time, the thrust generated by the elastic member 4 and the thrust generated by the centrifugal force and the magnetic attraction are in opposition, until the speed drops to zero, the centrifugal force disappears, and the magnetic attraction is greater than the thrust of the elastic member 4, and the guide disk returns to its original position. The elastic member 4 can be selected but not limited to a spring.

[0044] Preferably, a receiving hole 212 is opened on the end face of the mounting portion of the rotor bracket 21 close to the guide disk 22, one end of the fixing member 5 extends into the receiving hole 212 and is fixedly connected to the rotor bracket 21, and part of the elastic member 4 is received in the receiving hole 212, which can reduce the size of the rotor 2 and thus the size of the motor, and the elastic member 4 is not easily twisted during the stretching and compression process.

[0045] Based on the above structure, the working principle of the adaptive weak magnetic disc motor of this embodiment is:

[0046] In the static state, the centrifugal member 3 is not affected by the centrifugal force, and the centrifugal member 3 is located at the maximum axial depth of the cavity. The centrifugal member 3 will not generate axial thrust on the guide disk 22. The magnetic attraction between the rotor 2 and the stator 1 is greater than the thrust of the elastic member 4. The elastic member 4 is in a compressed state, and the air gap length between the permanent magnet 23 on the guide disk 22 and the stator 1 is the smallest.

[0047] When the shaft 7 drives the rotor 2 to rotate at a low speed, the sum of the axial thrust of the centrifugal part 3 and the thrust of the elastic part 4 on the guide magnetic disk 22 is smaller than the magnetic attraction between the rotor 2 and the stator 1, and the axial position of the guide magnetic disk 22 will not change. In addition, the motor adopts surface-mounted magnets with the highest torque density, and the motor has the highest low-speed torque.

[0048] When the shaft 7 drives the rotor 2 to rotate at a high speed, the axial thrust of the centrifugal member 3 on the guide magnetic disk 22 increases. When the sum of the axial thrust of the centrifugal member 3 and the thrust of the elastic member 4 is greater than the magnetic attraction, the guide magnetic disk 22 begins to move axially away from the rotor bracket 21, and the air gap length between the permanent magnet 23 and the stator 1 gradually increases to the maximum, and the magnetic field strength weakens, which can effectively improve the weak magnetic speed regulation performance of the motor under high-speed operation, and the motor has an ultra-large speed regulation range.

[0049] When the motor decelerates, the axial thrust of the centrifugal part 3 is not enough to counteract the magnetic attraction, and the guide magnetic disk 22 moves axially close to the rotor bracket 21. At this time, the thrust generated by the elastic part 4 and the thrust generated by the centrifugal force 3 counteract the magnetic attraction until the speed drops to zero and the centrifugal force disappears. At this time, the magnetic attraction is greater than the thrust of the elastic part 4, and the guide magnetic disk 22 returns to its original position.

[0050] The embodiments of the present invention are described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge scope of ordinary technicians in this field without departing from the purpose of the present invention.

Claims

1. An adaptive weak magnetic disk motor, characterized in that: include: Stator (1); A rotor (2), the rotor (2) comprising a rotor support (21) and a guide disk (22), the guide disk (22) being mounted on the rotor support (21) so as to rotate with the rotor, the guide disk (22) being axially slidable relative to the rotor support (21), a permanent magnet (23) being distributed on the end surface of the guide disk (22) opposite to the stator (1), and a cavity whose axial depth decreases along the radial direction being formed between the rotor support (21) and the guide disk (22); A centrifugal member (3) is contained in the cavity, and the centrifugal member (3) moves radially outward under the action of centrifugation to push the guide disk (22) axially away from the stator (1). The guide disk (22) comprises a radially distributed mounting portion and a working portion, the mounting portion being movably connected to the rotor support (21), the working portion being axially close to the stator relative to the mounting portion, and the permanent magnet (23) being attached to the end surface of the working portion opposite to the stator (1).

2. The adaptive weak magnetic disc motor according to claim 1, characterized in that: An elastic member is provided between the rotor support (21) and the guide disk (22).

3. The adaptive weak magnetic disc motor according to claim 2, characterized in that: The guide disk (22) is assembled on the rotor support (21) by means of a fixing member (5) and the fixing member (5) is arranged parallel to the axis.

4. The adaptive weak magnetic disc motor according to claim 3, characterized in that: The elastic member (4) is sleeved on the fixing member (5), and two ends of the elastic member (4) act on the rotor bracket (21) and the guide disk (22) respectively. In a stationary state, the elastic member (4) is in a compressed state under the action of magnetic attraction.

5. The adaptive weak magnetic disc motor according to claim 1, characterized in that: A first recess (211) is formed on the rotor support (21), and a second recess is formed on the guide disk (22); the first recess (211) and the second recess are opened relative to each other to form a cavity for accommodating the centrifugal element (3).

6. The adaptive weak magnetic disc motor according to claim 5, characterized in that: There are at least two cavities, and the at least two cavities are evenly distributed along the circumferential direction.

7. The adaptive weak magnetic disc motor according to claim 1, characterized in that: A counterweight (6) is arranged on the centrifugal member (3).

8. The adaptive weak magnetic disc motor according to claim 7, characterized in that: The counterweight (6) is hinged to the centrifugal member (3), and the counterweight (6) and the centrifugal member (3) slide radially together.

9. The adaptive weak magnetic disc motor according to claim 8, characterized in that: The rotor (2) is provided with a radial opening, and the counterweight (6) passes through the radial opening and slides along the radial opening.

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