Asymmetric disc motor

Abstract

The present application provides an asymmetric disc motor, the motor includes a housing, a front cover, a main shaft, a bearing assembly and at least one asymmetric stator-rotor combination, the front cover is detachably fixedly connected to the housing and forms an internal space for accommodating the main shaft and the asymmetric stator-rotor combination, the main shaft is rotatably connected to the housing and the front cover through the bearing assembly, and the end of the main shaft that passes through the front cover and protrudes from the internal space forms a main shaft output end, each asymmetric stator-rotor combination includes a first stator assembly, a rotor assembly, and a second stator assembly that are sequentially sleeved on the main shaft from near to far relative to the main shaft output end, and the axial magnetic attraction of the second stator assembly to its rotor assembly is greater than the axial magnetic attraction of the first stator assembly to its rotor assembly. The asymmetric disc motor of the present application can be applied to centrifugal fans, and can effectively solve the wear problem of the aerodynamic axial force on the bearings in the centrifugal fans.

Description

Technical Field

[0001] The present application belongs to the technical field of disc motors, and specifically provides an asymmetric disc motor. Background Art

[0002] High-speed fans with turbine and volute structures have the characteristics of high efficiency, large air volume and low noise. They have been widely used in industrial and civil applications such as ventilation, cooling and heat dissipation, and water oxygenation in aquaculture. The common high-speed fan head is generally made of Figure 1 For the radial flux motor plus turbine volute solution shown in the figure, in order to meet the oxygen filling index, the fan needs to rotate at high speed, which will generate an axial aerodynamic force of 100 to 200N on the motor shaft. The above axial aerodynamic force acts on the bearing, which will affect the operating stability of the bearing and increase its friction and wear. Therefore, the bearings of the radial flux motor need to adopt a front two and rear one structure. The front end adopts a DT-assembled ceramic angular contact bearing to withstand the aerodynamic axial force, the rear end adopts a ceramic angular contact bearing, and the front and rear bearings adopt a DF assembly.

[0003] Although the motor adopting the above solution can share the aerodynamic axial force by increasing the number of bearings, the continuous bearing of the axial force will still have a significant impact on the life of the bearings. According to statistics on the use of existing 15KW high-speed fans, the motor bearings of most fans need to be replaced after the running time reaches 4000 to 8000 hours. Therefore, it is urgent to provide a new type of motor that can solve the wear problem of the bearings caused by the above-mentioned aerodynamic axial force. Utility Model Content

[0004] In order to solve the problems existing in the above-mentioned prior art, the present application provides an asymmetric disc motor, comprising a housing, a front cover, a main shaft, a bearing assembly and at least one asymmetric stator-rotor combination; the front cover is detachably fixedly connected to the housing and forms an internal space for accommodating the main shaft and the asymmetric stator-rotor combination, the main shaft is rotatably connected to the housing and the front cover through the bearing assembly, and the end of the main shaft that penetrates the front cover and protrudes from the internal space forms a main shaft output end; each asymmetric stator-rotor combination comprises a first stator assembly, a rotor assembly, and a rotor assembly, which are sequentially sleeved on the main shaft from near to far relative to the main shaft output end. subassembly, and a second stator assembly; the first stator assembly includes a first iron core and a plurality of first coil windings wound on the first iron core, and the second stator assembly includes a second iron core and a plurality of second coil windings wound on the second iron core; the rotor assembly includes a plurality of first N-pole magnets and first S-pole magnets facing the first stator assembly, and a plurality of second N-pole magnets and second S-pole magnets facing the second stator assembly; in each asymmetric stator-rotor combination, the axial magnetic attraction of the second stator assembly to its rotor assembly is greater than the axial magnetic attraction of the first stator assembly to its rotor assembly.

[0005] Optionally, in each asymmetric stator-rotor combination, the radial length of the second N-pole magnet and the second S-pole magnet of its rotor assembly is greater than the radial length of the first N-pole magnet and the first S-pole magnet, and / or the radial size of the second iron core of its second stator assembly is greater than the radial size of the first iron core of its first stator assembly.

[0006] Optionally, in each asymmetric stator-rotor combination, the axial distance between the second N-pole magnet, the second S-pole magnet of its rotor assembly and the second iron core of its second stator assembly is smaller than the axial distance between the first N-pole magnet, the first S-pole magnet of its rotor assembly and the first iron core of its first stator assembly.

[0007] Further, each of the first N-pole magnets and the first S-pole magnets are alternately arranged along the circumferential direction, and each of the second N-pole magnets and the second S-pole magnets are alternately arranged along the circumferential direction.

[0008] Furthermore, the axial magnetic attraction forces of the first stator assembly and the second stator assembly of each asymmetric stator-rotor combination on its rotor assembly are respectively F i,1 、F i,2 , and F i,1 、F i,2 satisfy:

[0009]

[0010] Wherein, i is the number of the asymmetric stator-rotor combination.

[0011] Furthermore, the bearing assembly includes a first bearing and a second bearing, and the axial distance between the first bearing and the output end of the main shaft is smaller than the axial distance between the second bearing and the output end of the main shaft.

[0012] Preferably, the motor further comprises a pre-tightening structure, wherein the pre-tightening structure elastically abuts between a side of the second bearing facing away from the main shaft output end and the housing.

[0013] Preferably, the motor also includes an axial magnetic attraction force stabilizing mechanism, which includes a compression spring and a spring retaining ring sleeved on the main shaft; the spring retaining ring is located on the side of the first bearing facing away from the main shaft output end; the compression spring is located between the spring retaining ring and a spring blocking structure fixedly arranged on the main shaft or the rotor assembly.

[0014] An asymmetric disc motor provided by an embodiment of the present application has at least the following beneficial effects:

[0015] 1. The asymmetrically arranged first stator assembly and second stator assembly generate an axial magnetic attraction force in the opposite direction to the axial aerodynamic force relative to the rotor assembly, thereby balancing the axial load applied to the bearing under high-speed rotation conditions of the fan, and specifically alleviating the problem of increased bearing wear caused by large axial aerodynamic force;

[0016] 2. By setting up the axial magnetic attraction stabilization mechanism, the service life and operation stability of the high-speed fan can be further effectively improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a cross-sectional view of an existing radial magnetic fan;

[0018] Figure 2 A three-dimensional view of an asymmetric disc motor provided according to an embodiment of the present application;

[0019] Figure 3 An exploded view of the internal structure of an asymmetric disc motor provided according to some embodiments of the present application;

[0020] Figure 4 An exploded view of the internal structure of an asymmetric disc motor provided according to some embodiments of the present application;

[0021] Figure 5 A front view of a centrifugal fan provided according to some embodiments of the present application;

[0022] Figure 6 A cross-sectional view of a centrifugal fan provided according to some embodiments of the present application;

[0023] Figure 7a-7cIt is a schematic diagram of the axial force exerted on the main shaft 1 when the fan is in different states;

[0024] Figure 8 A partially enlarged schematic diagram of an axial magnetic attraction stabilization mechanism provided according to some embodiments of the present application;

[0025] Fig. 9 A partially enlarged schematic diagram of an axial magnetic attraction stabilization mechanism provided according to some embodiments of the present application;

[0026] Fig.10 A partially enlarged schematic diagram of an axial magnetic attraction stabilization mechanism provided according to some embodiments of the present application;

[0027] Numbers in the figure

[0028] Spindle 1, first spindle section 101, first spindle section 101', second spindle section 102, second spindle section 102', collar 103', asymmetric stator-rotor combination 2, first stator component 21, first coil winding structure 211, first iron core 212, first fixing portion 213, second stator component 22, second coil winding structure 221, second iron core 222, second fixing portion 223, rotor component 23, first N-pole magnet 2311, first S-pole magnet 2312, second N-pole magnet 2321, second S-pole magnet 2322, rotor back plate 233, first bearing 31, second bearing 32, axial magnetic attraction stabilizing mechanism 4, compression spring 41, spring retaining ring 42, front cover 5, housing 6. DETAILED DESCRIPTION

[0029] The present application is further described below based on preferred embodiments and with reference to the accompanying drawings. For ease of understanding, various components on the drawings are enlarged or reduced, but this practice is not intended to limit the protection scope of the present application.

[0030] In the description of the embodiments of the present application, it should be noted that if the terms "upper", "lower", "inside", "outside", etc. indicate an orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the products of the embodiments of the present application are usually placed when in use, it is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, in the description of the present application, in order to distinguish different units, the words first, second, etc. are used in this specification, but these are not limited by the order of manufacture, nor can they be understood as indicating or implying relative importance, and their names may be different in the detailed description and claims of the present application.

[0031] The vocabulary in this specification is used to illustrate the embodiments of the present application, but is not intended to limit the present application. It should also be noted that, unless otherwise clearly specified and limited, the terms "disposed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, a direct connection, an indirect connection through an intermediate medium, or a connection between the two elements. For those skilled in the art, the specific meanings of the above terms in this application can be specifically understood.

[0032] The present application provides an asymmetric disc motor. Figure 2 is a three-dimensional view of the motor provided according to some embodiments of the present application, Figure 3 , Figure 4 The exploded view of the internal structure of the motor (the front cover 5 and the housing 6 are hidden). Figure 2-Figure 4 As shown, in some embodiments, the asymmetric disc motor of the present application includes a motor housing composed of a front cover 5 and a shell 6, the interior of which constitutes an internal space for accommodating a main shaft 1, an asymmetric stator-rotor combination 2 and a bearing assembly.

[0033] In the embodiment of the present application, the number of asymmetric stator-rotor combinations of the asymmetric disc motor may be 1, 2, 3 or more (i may be used as the number of each combination).

[0034] Among them, each asymmetric stator-rotor combination 2 includes a first stator component 21, a rotor component 23, and a second stator component 22, wherein the first stator component 21, the rotor component 23, and the second stator component 22 are sequentially sleeved on the main shaft 1 from one end to the other end of the main shaft 1, and the rotor component 23 is fixedly connected to the main shaft 1.

[0035] Furthermore, the front cover 5 is provided with a through hole for the main shaft 1 to pass through, and the front cover 5 is sleeved on the main shaft 1 near the first stator assembly 21 side; the bearing assembly includes a first bearing 31 and a second bearing 32, the inner ring of the first bearing 31 is sleeved on the main shaft 1 near the first stator assembly 21 side, and the inner ring of the second bearing 32 is sleeved on the main shaft 1 near the second stator assembly 22 side, and axially limited by a stepped shoulder structure formed on the main shaft 1, and the outer rings of the two bearings are respectively fixedly connected to the front cover 5 and the housing 6, so that the main shaft 1 can rotate relative to the front cover 5 and the housing 6. When in use, the end of the main shaft 1 close to the first stator assembly 21 protrudes from the internal space through the through hole of the front cover 5, and forms a motor output end, which can be fixedly connected to other actuators such as the turbine assembly of the fan, thereby driving the actuator to rotate.

[0036] In some preferred embodiments, the asymmetric disc motor also includes a pre-tightening structure, and a pre-tightening force is applied to the main shaft 1 by setting the pre-tightening structure to ensure good axial limitation of the main shaft 1. Specifically, the pre-tightening structure can adopt a wave spring, or a similar elastic retaining ring that can provide elastic force, etc., which is sleeved on the main shaft 1 and elastically abutted against the side of the second bearing 32 facing away from the output end of the main shaft 1 and the housing respectively. During the motor assembly process, the pre-tightening structure is gradually compressed and a pre-tightening force is applied to the main shaft 1 through the second bearing 32.

[0037] In some preferred embodiments, the first bearing 31 and the second bearing 32 may be ceramic angular contact bearings to improve the bearing capacity of the bearings to the axial load and extend the bearing life.

[0038] In some preferred embodiments, an anti-creep O-ring is sleeved between the retaining frame and the outer ring of the second bearing 32 to prevent radial creep from occurring during the rotation of the main shaft 1 .

[0039] Specifically, the first stator assembly 21 includes a first core 212 and a plurality of first coil windings wound on the first core 212 , and the second stator assembly 22 includes a second core 222 and a plurality of second coil windings wound on the second core 222 .

[0040] Among them, the first iron core 212 and the second iron core 222 can use silicon steel and other materials with high magnetic permeability and low hysteresis loss characteristics. The side facing the rotor assembly forms tooth poles and tooth slots extending radially and alternately distributed along the circumferential direction. Slot insulation is provided in the tooth slots. The coil is wound on the tooth poles to form the first coil winding and the second coil winding respectively. The first coil winding structure 211 and the second coil winding structure 221 in the figure schematically show the overall structure formed after the first coil winding and the second coil winding are arranged. Further, the first iron core 212 is protruded on one side facing away from the rotor assembly 23 to form a first fixing portion 213, and the first fixing portion 213 can be fixedly connected to the front cover 5 by multiple bolts. Correspondingly, the second iron core 222 is protruded on one side facing away from the rotor assembly 23 to form a second fixing portion 223, and the second fixing portion 223 can be fixedly connected to the rear end of the housing 6 by multiple bolts.

[0041] Correspondingly, the rotor assembly 23 includes a circular rotor back plate 233, and a plurality of first N-pole magnets 2311, first S-pole magnets 2312, second N-pole magnets 2321 and second S-pole magnets 2322, wherein the rotor back plate 233 is sleeved on the main shaft 1 and fixedly connected to the main shaft 1, each of the first N-pole magnets 2311 and the first S-pole magnets 2312 are fixedly arranged on the side of the rotor back plate 233 facing the first stator assembly 21 and are alternately arranged along the circumferential direction, and each of the second N-pole magnets 2321 and the second S-pole magnets 2322 are fixedly arranged on the side of the rotor back plate 233 facing the second stator assembly 22 and are also alternately arranged along the circumferential direction.

[0042] Each first coil winding and the second coil winding can be driven by alternating current or direct current, and each first coil winding and the second coil winding can be connected to a control unit (not shown) in a wiring manner known to those skilled in the art, and the current direction in the first coil winding and the second coil winding is alternately changed to achieve an alternating change in the polarity of the electromagnetic field, thereby driving the rotor assembly 23 to drive the main shaft 1 to rotate relative to the housing. The working principle of the above disc type is already known to those skilled in the art, and will not be repeated here.

[0043] As analyzed in the background technology, during the operation of a fan with a turbine-volute structure, when the airflow passes through the impeller of the centrifugal fan, the curvature and angle design of the blades cause the airflow to generate a pressure gradient on the impeller, thereby generating aerodynamic force, wherein the aerodynamic force directed axially from the motor toward the impeller is called axial aerodynamic force. Since the bearings mounted on the main shaft 1 are positioned by structures such as the shaft shoulder of the main shaft 1, the above-mentioned axial aerodynamic force will also be transmitted to the bearings. During the high-speed rotation of the fan, the above-mentioned axial aerodynamic force will greatly increase the friction of the bearings, accelerate their wear rate and affect their operating stability.

[0044] To this end, in an embodiment of the present application, the rotor assembly 23 in the asymmetric disc motor and the two stator assemblies on both sides thereof are arranged into an asymmetric stator-rotor combination. Specifically, in an asymmetric stator-rotor combination (taking the i-th combination as an example), the axial distance between the second stator assembly 22 and the output end of the main shaft 1 is greater than the axial distance between the first stator assembly 21 and the output end of the main shaft 1, that is, the second stator assembly 22 is farther away from the output end of the main shaft 1 than the first stator assembly 21. At the same time, the second iron core 222 in the second stator assembly 22 generates an axial magnetic attraction F in the direction away from the output end of the main shaft 1 on the second N-pole magnet 2321 and the second S-pole magnet 2322 in the rotor assembly 23. i2 is greater than the axial magnetic attraction F generated by the first iron core 212 in the first stator assembly 21 on the first N-pole magnet 2311 and the first S-pole magnet 2312 in the rotor assembly 23 toward the output end of the main shaft 1 i1Therefore, the above two stator components will generate a force on the rotor component 23 in the opposite direction to the axial aerodynamic force, with a magnitude of F i2 -F i1 The axial magnetic attraction resultant force is further transmitted to the main shaft 1 through the rotor assembly 23, thereby effectively offsetting the axial load on the bearing exerted by the axial aerodynamic force generated during the high-speed operation of the fan, greatly delaying the wear rate of the bearing, and effectively increasing its operating stability and service life.

[0045] A variety of implementations can be used to generate the above-mentioned axial magnetic attraction force. For example, in some preferred embodiments, the radial length H2 of the second N-pole magnet 2321 and the second S-pole magnet 2322 can be set to be greater than the radial length H1 of the first N-pole magnet 2311 and the first S-pole magnet 2312; in other preferred embodiments, the radial dimension h2 of the second iron core 222 can also be set to be greater than the radial dimension h1 of the first iron core 212 at the same time or separately. Through the asymmetric arrangement of the above-mentioned magnets and / or iron cores, the rotor assembly 23 can always be subjected to a direction opposite to the axial aerodynamic force, with a magnitude of F i2 -F i1 The resultant axial magnetic attraction force.

[0046] For example, in some other preferred embodiments, the axial distance between the second N-pole magnet 2321 and the second S-pole magnet 2322 and the second iron core 222 can be set to be smaller than the axial distance between the first N-pole magnet 2311 and the first S-pole magnet 2312 and the first iron core 212, and an axial magnetic attraction force in the opposite direction to the axial aerodynamic force is generated by adjusting the spacing between the rotor assembly 23 and the two stator assemblies.

[0047] Figure 5 and Figure 6 The front view and cross-sectional view of a centrifugal fan driven by the asymmetric disc motor provided in some embodiments of the present application are shown. As shown in the figure, the centrifugal fan includes a turbine, a volute and the asymmetric disc motor provided in any one of the above embodiments, wherein the front cover 5 is fixedly connected to the volute as a connecting flange, and the turbine is located in the volute and fixedly connected to the output end of the main shaft 1.

[0048] Figure 7a-7c The axial forces on the main shaft 1 when the fan is in different states are shown respectively. Figure 7a and Figure 7bIt can be seen that when the fan is in a stationary state, the axial aerodynamic force is zero, and there is only a rightward axial magnetic attraction force, which is transmitted from the main shaft 1 to the second bearing 32 (it should be noted that when a pre-tightening structure exists, the second bearing 32 is always subject to the pre-tightening force applied by the pre-tightening structure). However, since the main shaft 1 does not rotate at this time, it will not cause wear on the bearing. During the acceleration process of the fan, as the axial aerodynamic force gradually increases from zero, the difference between the axial aerodynamic force and the axial magnetic attraction force gradually reaches a balance, and the axial force acting on the second bearing 32 gradually decreases, thereby reducing the bearing wear problem caused by the larger axial force when the main shaft 1 rotates. Furthermore, as Figure 7c As shown, the axial magnetic attraction resultant force can be set to be slightly smaller than the axial aerodynamic force of the fan when it is in the design working condition, that is, as the acceleration process continues, the resultant force of the axial magnetic attraction and the axial aerodynamic force on the second bearing 32 gradually decreases until they cancel each other out. When the speed continues to increase, the axial aerodynamic force will exceed the axial magnetic attraction resultant force, so that the resultant force of the two is to the left and transmitted to the side of the first bearing 31 facing the stator-rotor combination. Setting the value of the axial magnetic attraction resultant force to be slightly smaller than the axial aerodynamic force corresponding to the design working condition can ensure that the first bearing 31 is within a reasonable axial force range when the fan is working stably for a long time, while alleviating its friction loss and ensuring the stable operation of the fan.

[0049] In order to ensure that the overall power of the wind turbine reaches the design index, each N-pole magnet and S-pole magnet has strong magnetic characteristics. Therefore, for any asymmetric stator-rotor combination i, the ratio of the axial magnetic attraction generated by the iron cores of the two stator components on the magnets on the rotor component 23 to the axial magnetic attraction force finally formed by the two stator components on the rotor component 23 may reach 8 to 10 times, that is, it satisfies the following formula:

[0050]

[0051] Therefore, the resultant axial magnetic attraction force on the rotor assembly 23 is quite sensitive to the change of its axial position, that is, a slight deviation of the rotor assembly 23 from the designed position along the axial direction may cause a large change in the resultant axial magnetic attraction force on the rotor assembly 23; however, there are assembly tolerances in the shaft system structure during the assembly process. At the same time, during the acceleration of the fan, as the axial aerodynamic force continues to increase and exceeds F i2 -F i1 The rotor assembly 23 inevitably has a slight displacement toward the turbine 2, which will cause the rotor assembly 23 to be subjected to F i1 Rapid increase, F i2 Rapid decrease, resulting in F i2 -F i1A sharp drop occurs, and the offsetting effect of the axial magnetic attraction force on the axial aerodynamic force is further ineffective. Therefore, an axial magnetic attraction stabilizing mechanism is needed to prevent the rotor assembly 23 from shifting toward the output end of the main shaft 1, so that it can generate a stable axial magnetic attraction force.

[0052] To this end, in some preferred embodiments, Figure 6 ,as well as Figures 8 to 10 As shown in the enlarged schematic diagram, the asymmetric disc motor also includes an axial magnetic attraction stabilizing mechanism 4, which can be arranged between the first bearing 31 and the rotor assembly 23, and is used to stabilize the difference between the axial magnetic attraction of the second stator assembly 22 on the rotor assembly 23 and the axial magnetic attraction of the first stator assembly 21 on the rotor assembly 23 (i.e., F i2 -F i1 ) remain within the design range.

[0053] In some preferred embodiments, the axial magnetic force stabilizing mechanism 4 includes a compression spring 41 and a spring retaining ring 42 which are sleeved on the main shaft 1, wherein the spring retaining ring 42 is located on the side of the first bearing 31 facing the output end of the main shaft 1, and the compression spring 41 is located between the spring retaining ring 42 and the spring blocking structure fixed on the main shaft 1 or the rotor assembly 23.

[0054] The spring blocking structure can be implemented in a variety of ways, for example, Figure 8 As shown, the main shaft 1 has a first main shaft section 101 with a relatively thin shaft diameter near the first bearing 31, and the compression spring 41 is sleeved on the first main shaft section 101. The main shaft 1 has a second main shaft section 102 with a relatively thick shaft diameter near the rotor assembly 23. A step-shaped shoulder is formed at the connection between the first main shaft section 101 and the second main shaft section 102, which can serve as a spring blocking structure.

[0055] In addition, you can Fig. 9 As shown in the embodiment, the first section 101' and the second section 102' of the main shaft are set to have the same shaft diameter, and the rotor back plate 233 in the rotor assembly 23 is directly used as a spring blocking structure on the side facing the output end of the main shaft 1. Alternatively, it can also be like Fig.10 As shown, a protruding collar 103' is added at the joint portion of the first main shaft section 101' and the second main shaft section 102' to serve as a spring blocking structure.

[0056] In some preferred embodiments, the motor further includes a sealing component. When the motor is used in an aeration system for aquaculture or in other relatively humid environments, the further setting of the sealing component can avoid the problem of humid water vapor entering the motor due to negative pressure generated by the cavity where the motor is located relative to the external environment after shutdown. Specifically, the sealing component includes a skeleton oil seal, which is sleeved on the main shaft 1 to seal the gap between the front cover 5 and the main shaft 1; further, the sealing component also includes a sealing ring, which is arranged between the front cover 5 and the shell 6. Specifically, the sealing ring is an elastic circle, which is pre-buried in the annular groove on the front cover 5. When the front cover 5 and the shell 6 are assembled, the sealing ring is squeezed to achieve the sealing of the gap between the front cover 5 and the shell 6.

[0057] As described above, in the embodiments of the present application, the number of asymmetric stator-rotor combinations may exceed one. By increasing the number of combinations, the power of each stator-rotor combination may be reduced accordingly, thereby achieving more precise regulation of the axial magnetic attraction force.

[0058] The above is a detailed introduction to the specific implementation methods of the present application. For those skilled in the art, several improvements and modifications may be made to the present application without departing from the principles of the present application. These improvements and modifications also fall within the scope of protection of the claims of the present application.

Claims

1. An asymmetric disc motor, characterized in that: It includes a housing, a front cover, a main shaft, a bearing assembly and at least one asymmetric stator-rotor combination; The front cover is detachably fixedly connected to the housing and forms an internal space for accommodating the main shaft and the asymmetric stator-rotor combination. The main shaft is rotatably connected to the housing and the front cover through a bearing assembly, and the end of the main shaft that penetrates the front cover and protrudes from the internal space forms a main shaft output end; Each asymmetric stator-rotor combination comprises a first stator assembly, a rotor assembly, and a second stator assembly which are sequentially sleeved on the main shaft from near to far relative to the main shaft output end; The first stator assembly includes a first iron core and a plurality of first coil windings wound on the first iron core, and the second stator assembly includes a second iron core and a plurality of second coil windings wound on the second iron core; the rotor assembly includes a plurality of first N-pole magnets and a first S-pole magnet facing the first stator assembly, and a plurality of second N-pole magnets and a second S-pole magnet facing the second stator assembly; In each asymmetric stator-rotor combination, the axial magnetic attraction force of the second stator component on its rotor component is greater than the axial magnetic attraction force of the first stator component on its rotor component.

2. The asymmetric disc motor according to claim 1, characterized in that: In each asymmetric stator-rotor combination, the radial lengths of the second N-pole magnet and the second S-pole magnet of the rotor assembly are greater than the radial lengths of the first N-pole magnet and the first S-pole magnet. And / or the radial size of the second core of its second stator assembly is greater than the radial size of the first core of its first stator assembly.

3. The asymmetric disc motor according to claim 1, characterized in that: In each asymmetric stator-rotor combination, the axial distance between the second N-pole magnet, the second S-pole magnet of the rotor assembly and the second iron core of its second stator assembly is smaller than the axial distance between the first N-pole magnet, the first S-pole magnet of the rotor assembly and the first iron core of its first stator assembly.

4. The asymmetric disc motor according to any one of claims 1 to 3, characterized in that: The first N-pole magnets and the first S-pole magnets are alternately arranged along the circumferential direction, and the second N-pole magnets and the second S-pole magnets are alternately arranged along the circumferential direction.

5. The asymmetric disc motor according to claim 1, characterized in that: The axial magnetic attraction forces of the first stator assembly and the second stator assembly of each asymmetric stator-rotor combination to its rotor assembly are F i,1 、F i,2 , and F i,1 、F i,2 satisfy: Wherein, i is the number of the asymmetric stator-rotor combination.

6. The asymmetric disc motor according to claim 1, characterized in that: The bearing assembly includes a first bearing and a second bearing, and the axial distance between the first bearing and the output end of the main shaft is smaller than the axial distance between the second bearing and the output end of the main shaft.

7. The asymmetric disc motor according to claim 6, characterized in that: It also includes a pre-tightening structure, which is elastically abutted between the side of the second bearing facing away from the main shaft output end and the housing.

8. The asymmetric disc motor according to claim 6, characterized in that: It also includes an axial magnetic attraction force stabilization mechanism, which includes a compression spring and a spring retaining ring sleeved on the main shaft; the spring retaining ring is located on the side of the first bearing facing away from the main shaft output end; the compression spring is located between the spring retaining ring and a spring blocking structure fixedly arranged on the main shaft or the rotor assembly.

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