Double-rotor disc-type high-speed fan and its design method

Abstract

The present application provides a double-rotor disc-type high-speed fan and its design method. The double-rotor disc-type high-speed fan includes a housing assembly and a turbine, a double-rotor disc-type motor, and a bearing assembly inside it. The double-rotor disc-type motor includes a main shaft and at least one single-stator double-rotor combination. The main shaft is fixedly connected to the turbine, and the bearing assembly is sleeved between the main shaft and the housing assembly. The single-stator double-rotor combination includes a first rotor assembly, a stator assembly, and a second rotor assembly that are sequentially sleeved on the main shaft along the axial direction. In each single-stator double-rotor combination, its stator assembly is fixedly connected to the housing assembly, the axial distance between its second rotor assembly and the turbine is greater than the axial distance between its first rotor assembly and the turbine, and the axial magnetic suction force of its stator assembly on its first rotor assembly is greater than the axial magnetic suction force of its stator assembly on its second rotor assembly. The high-speed fan provided by the present application can effectively improve the service life and operation stability of the high-speed fan.

Description

Technical Field

[0001] This application belongs to the technical field of high-speed blowers. Specifically, a dual-rotor disc-type high-speed blower and its design method are provided. Background Art

[0002] High-speed blowers with a turbine and volute structure have the characteristics of high efficiency, large air volume, and low noise, and have been widely used in industrial and civil applications such as ventilation and air change, cooling and heat dissipation, and water body aeration in the aquaculture field. When the blower rotates at high speed, the turbine will generate an axial aerodynamic force towards the turbine on the motor shaft. As the rotational speed increases, this axial aerodynamic force can reach the order of 100 - 200 N. The above axial aerodynamic force acts on the bearings, which will affect the running stability of the bearings and increase their friction and wear. Therefore, the existing high-speed blowers adopt a bearing arrangement with two front bearings and one rear bearing, and ceramic angular contact bearings in DT combination are arranged at the front end to share the pneumatic axial force and improve the service life.

[0003] Although the high-speed blowers adopting the above scheme can share the pneumatic axial force by increasing the number of bearings, continuously bearing the axial force will still have a non-negligible impact on the bearing life. According to the statistics of the usage of existing 15KW-class high-speed blowers, most blowers need to replace their motor bearings after the running time reaches 4000 - 8000 h. Summary of the Invention

[0004] To solve the problems existing in the above-mentioned prior art, this application provides a dual-rotor disc-type high-speed blower, which includes a housing assembly, a turbine, a dual-rotor disc-type motor, and a bearing assembly arranged inside the housing assembly. The dual-rotor disc-type motor includes a main shaft and at least one single-stator dual-rotor combination. The main shaft is fixedly connected to the turbine, and the bearing assembly is sleeved between the main shaft and the housing assembly; the single-stator dual-rotor combination includes a first rotor assembly, a stator assembly, and a second rotor assembly sleeved on the main shaft in sequence along the axial direction; in each single-stator dual-rotor combination, its stator assembly is fixedly connected to the housing assembly, the axial distance between its second rotor assembly and the turbine is greater than the axial distance between its first rotor assembly and the turbine, and the axial magnetic suction force of its stator assembly on its first rotor assembly is greater than the axial magnetic suction force of its stator assembly on its second rotor assembly.

[0005] Further, the stator assembly includes: an iron core, multiple groups of first coil windings, and multiple groups of second coil windings; the multiple groups of first coil windings are arranged on the side of the iron core facing the turbine and are circumferentially spaced apart, and the multiple groups of second coil windings are arranged on the side of the iron core facing away from the turbine and are circumferentially spaced apart.

[0006] Further, the first rotor assembly includes a plurality of first N - pole magnets and first S - pole magnets facing the stator assembly, and each of the first N - pole magnets and first S - pole magnets is arranged alternately in the circumferential direction; the second rotor assembly includes a plurality of second N - pole magnets and second S - pole magnets facing the stator assembly, and each of the second N - pole magnets and second S - pole magnets is arranged alternately in the circumferential direction; the axial magnetic suction force of the iron core on the first N - pole magnets and first S - pole magnets is greater than the axial magnetic suction force of the iron core on the second N - pole magnets and second S - pole magnets.

[0007] Preferably, the radial length of the first N - pole magnets and the first S - pole magnets is greater than the radial length of the second N - pole magnets and the second S - pole magnets, and / or the radial dimension of the iron core on the side facing the turbine is greater than the radial dimension of the side facing away from the turbine.

[0008] Preferably, the axial distance between the first N - pole magnets and the first S - pole magnets and the iron core is less than the axial distance between the second N - pole magnets and the second S - pole magnets and the iron core.

[0009] Further, the bearing assembly includes a first bearing and a second bearing, and the axial distance between the first bearing and the turbine is less than the axial distance between the second bearing and the turbine.

[0010] Preferably, the double - rotor disk - type high - speed fan further includes a pre - tightening structure, and the pre - tightening structure elastically abuts between one end of the second bearing facing away from the turbine and the housing assembly.

[0011] Preferably, the double - rotor disk - type high - speed fan further includes an axial magnetic suction force stabilizing mechanism for maintaining the resultant axial magnetic suction force received by the main shaft within the design range, wherein the direction of the resultant axial magnetic suction force is along the axial direction away from the turbine, and the magnitude is the difference between the axial magnetic suction forces of the stator assembly on the first rotor assembly and the second rotor assembly.

[0012] Further, the axial magnetic suction force stabilizing mechanism includes a compression spring and a spring retaining ring sleeved on the main shaft; the spring retaining ring is located at one end of the first bearing facing away from the turbine; the compression spring is located between the spring retaining ring and a spring blocking structure fixedly arranged on the main shaft or the first rotor assembly.

[0013] Preferably, the length of the compression spring is set to satisfy the following constraint condition: when the double - rotor disk - type high - speed fan is in a stationary state, the elastic deformation force generated by the compression of the compression spring by the spring retaining ring and the spring blocking structure is less than a preset elastic deformation force threshold.

[0014] Preferably, the elastic coefficient of the compression spring is determined based on the following steps:

[0015] Apply a virtual displacement towards the turbine to the main shaft, where the magnitude of the virtual displacement does not exceed the relative displacement of the main shaft caused by the maximum axial aerodynamic force; calculate the resultant axial magnetic suction force on the main shaft when the virtual displacement occurs; determine the elastic coefficient of the compression spring based on the magnitude of the virtual displacement, the resultant axial magnetic suction force on the main shaft in the stationary state, and the resultant axial magnetic suction force on it when the virtual displacement occurs.

[0016] Furthermore, the housing assembly includes an air inlet, a volute, a connecting flange, and a rear housing that are fixedly connected in sequence along the axial direction, and the stator assembly is fixedly connected to the rear housing.

[0017] Preferably, the double-rotor disc high-speed fan further includes a skeleton oil seal and / or a sealing ring; the skeleton oil seal is arranged on the side of the connecting flange facing the volute to seal the gap between the connecting flange and the main shaft; the sealing ring is arranged on the side of the connecting flange facing the rear housing to seal the gap between the connecting flange and the rear housing.

[0018] Preferably, an anti-creeping O-ring is also sleeved between the cage and the outer ring of the second bearing.

[0019] Preferably, the number of the single-stator double-rotor combinations is greater than or equal to 1.

[0020] This application also provides a design method for a double-rotor disc high-speed fan through embodiments, which is used to design the aforementioned double-rotor disc high-speed fan, and includes the following steps:

[0021] Determine the design conditions of the double-rotor disc high-speed fan based on the design indicators of the double-rotor disc high-speed fan;

[0022] Based on the design conditions, determine the specifications of the turbine and the volute, and the power range W of the double-rotor disc high-speed fan when it reaches the design conditions Target ;

[0023] Calculate the axial aerodynamic force F of the double-rotor disc high-speed fan under the design conditions P ;

[0024] Based on F P Determine the value range of the resultant axial magnetic suction force F Target , where the direction of F Target is opposite to the direction of F P ;

[0025] Design the specification parameters of the stator assembly, the first rotor assembly, and the second rotor assembly so that when the double-rotor disc high-speed fan is in the stationary state, the magnetic suction force F of the stator assembly on the first rotor assembly1 The difference from the magnetic suction force F on the second rotor assembly 2 satisfies F Target , and when the dual-rotor disc high-speed fan reaches the designed operating conditions, the power W for driving the first rotor assembly by the stator assembly 1 and the power W for driving the second rotor assembly by it 2 sum satisfies W Target .

[0026] Preferably, the dual-rotor disc high-speed fan further includes an axial magnetic suction force stabilizing mechanism, including a spring retainer and a compression spring sleeved on the main shaft. The design method further includes the following steps: determining the length and elastic coefficient of the compression spring.

[0027] Further, the elastic coefficient of the compression spring is determined through the following steps:

[0028] Apply a virtual displacement towards the turbine to the main shaft, and the magnitude of the virtual displacement does not exceed the relative displacement of the main shaft caused by the maximum axial aerodynamic force;

[0029] Calculate the resultant axial magnetic suction force on the main shaft when the virtual displacement occurs;

[0030] Determine the elastic coefficient of the compression spring based on the magnitude of the virtual displacement, the resultant axial magnetic suction force on the main shaft in the static state, and the resultant axial magnetic suction force on the main shaft when the virtual displacement occurs.

[0031] For the dual-rotor disc high-speed fan provided by the present application, an additional resultant axial magnetic suction force is generated on the main shaft by the asymmetrically arranged stator assembly, the first rotor assembly, and the second rotor assembly. The direction of the resultant axial magnetic suction force is opposite to the axial aerodynamic force exerted on the main shaft by the high-speed rotation of the turbine, thereby balancing the axial load exerted on the bearing under the high-speed rotation condition of the fan. By using the dual-rotor disc high-speed fan provided by the present application, it is possible to specifically alleviate the problem of aggravated bearing wear caused by a large axial aerodynamic force without increasing the number of bearings, effectively improving the service life and operation stability of the high-speed fan. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is a perspective view of the dual-rotor disc high-speed fan provided according to an embodiment of the present application;

[0033] Figure 2 is a front view of the dual-rotor disc high-speed fan provided according to some embodiments of the present application;

[0034] Figure 3 is a cross-sectional view of the dual-rotor disc high-speed fan provided according to an embodiment of the present application;

[0035] Figure 4 Exploded view of a dual-rotor disc-type high-speed fan provided according to some embodiments of the present application;

[0036] Figure 5 Exploded view of a single-stator dual-rotor disc-type motor provided according to some embodiments of the present application;

[0037] Figure 6 Exploded view of a single-stator dual-rotor disc-type motor provided according to some embodiments of the present application;

[0038] Figure 7 Schematic structural diagram of an iron core provided according to some embodiments of the present application;

[0039] Figure 8 Schematic diagram of the force condition of the shafting structure when the fan is in a stationary state in one embodiment;

[0040] Figure 9 Schematic diagram of the force condition of the shafting structure at a certain moment during the acceleration process of the fan in one embodiment;

[0041] Figure 10 Schematic diagram of the force condition of the shafting structure when the fan is at the design condition in one embodiment;

[0042] Figure 11 Cross-sectional view of a dual-rotor disc-type high-speed fan provided according to some embodiments of the present application;

[0043] Figure 12 For Figure 11 Enlarged view of circle B in;

[0044] Figure 13 Partially enlarged schematic diagram of a spring blocking structure provided according to some embodiments of the present application;

[0045] Figure 14 Flow chart of determining the elastic coefficient of a compression spring provided according to some embodiments of the present application;

[0046] Figure 15 Flow chart of the design method of a dual-rotor disc-type high-speed fan provided according to an embodiment of the present application.

[0047] Reference numerals in the figure

[0048] Air inlet 11, volute 12, rear housing 13, connecting flange 14, sealing ring 15, skeleton oil seal 16, turbine 2, dual-rotor disc motor 3, main shaft 30, shaft collar 301, first rotor assembly 31, first back plate 311, first N-pole magnet 3121, first S-pole magnet 3122, second rotor assembly 32, second back plate 321, second N-pole magnet 3221, second S-pole magnet 3222, stator assembly 33, fixing part 331, iron core 332, first tooth pole 3321, second tooth pole 3322, isolation part 3323, first coil winding 3331, second coil winding 3332, first bearing 41, second bearing 42, wave spring 421, anti-creeping O-ring 422, axial magnetic attraction stabilizing mechanism 6, compression spring 61, spring retainer 62. Detailed implementation manners

[0049] Hereinafter, the present application will be further described based on preferred implementation manners with reference to the drawings. For the convenience of understanding, various components in the drawings are enlarged or reduced, but this is not intended to limit the protection scope of the present application.

[0050] In the description of the embodiments of the present application, it should be noted that if terms such as "upper", "lower", "inner", "outer", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the products in the embodiments of the present application are usually placed during use, it is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application. In addition, in the description of the present application, in order to distinguish different units, the terms "first", "second", etc. are used in this specification, but these are not limited by the manufacturing sequence and should not be construed as indicating or implying relative importance. In the detailed description and claims of the present application, their names may be different.

[0051] The terms in this specification are used to describe the embodiments of the present application, but are not intended to limit the present application. It should also be noted that unless otherwise clearly specified and limited, if terms such as "set", "connected", "connected" are used, they 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, or an indirect connection through an intermediate medium, and it can be the communication inside two elements. For those skilled in the art, the specific meanings of the above terms in the present application can be specifically understood.

[0052] The present application provides a dual-rotor disc high-speed fan. Figure 1 A perspective view of the dual-rotor disc high-speed fan provided according to some embodiments of the present application. Figures 2 to 4They are respectively the front view, the sectional view taken along line A-A, and the exploded view of the double-rotor disc type high-speed fan. Refer to Figures 2 to 4 , the double-rotor disc type high-speed fan includes an external housing assembly, and a turbine 2, a double-rotor disc type motor 3 and a bearing assembly disposed inside the housing assembly.

[0053] In some specific embodiments, such as Figures 1 to 4 shown, the housing assembly sequentially includes an air inlet 11, a volute 12, a connecting flange 14 and a rear housing 13 from left to right. The air inlet 11 is generally in a ring structure with a gradually shrinking diameter, and is fixedly connected to the volute 12 through a plurality of bolts; there is a space for accommodating the turbine 2 inside the volute 12, and this space gradually spirally expands in the radial direction and finally forms an exhaust duct.

[0054] The connecting flange 14 is disposed between the volute 12 and the rear cover. The radial end thereof has a stepped limiting structure towards the volute 12 side, and this limiting structure is adapted to the corresponding part on the volute 12. The volute 12 and the rear cover are fixedly connected through a plurality of bolts, and the connecting flange 14 is firmly clamped between the two through the above-mentioned limiting structure.

[0055] The assembly method of the above housing assembly is already known to those skilled in the art. Obviously, on the basis of not departing from the principle of the present application, other optional fixed connection methods (such as snap-fitting, clamping, etc.) can also be used for the assembly of the above housing assembly.

[0056] Furthermore, as Figure 3 and Figure 4 shown, in some embodiments, the double-rotor disc type motor 3 includes a main shaft 30, and at least one set of single-stator double-rotor combinations composed of a first rotor assembly 31, a stator assembly 33, and a second rotor assembly 32. Among them, the first rotor assembly 31, the stator assembly 33, and the second rotor assembly 32 are sequentially sleeved on the main shaft 30 from the air inlet 11 side to the rear housing 13 side.

[0057] The inner rings of the first bearing 41 and the second bearing 42 are respectively sleeved on one end of the main shaft 30 close to the air inlet 11 and one end close to the rear housing 13, and are axially limited by the stepped shoulder structure formed on the main shaft 30. At the same time, the outer rings of the two bearings are respectively embedded in the bearing accommodation spaces on the connecting flange 14 and the rear housing 13, so as to realize the rotation of the main shaft 30 relative to the housing assembly.

[0058] In some preferred embodiments, a pre-tightening structure can be provided to apply a pre-tightening force to the main shaft 30 to ensure good axial limitation of the main shaft 30, such as Figure 3 and Figure 4As shown, the preloading structure can adopt a wave spring 421, or an elastic retaining ring or the like that can provide elastic force. It is sleeved on the main shaft 30 and elastically abuts against one end of the second bearing 42 facing away from the turbine 2 and the rear cover respectively. During the assembly process of the rear cover and the volute 12, the preloading structure is gradually compressed, and a preloading force is applied to the main shaft 30 through the second bearing 42. In some preferred embodiments, as Figure 4 shown, an anti-creep O-ring 422 is also sleeved between the cage and the outer ring of the second bearing 42 to prevent radial creep during the rotation of the main shaft 30.

[0059] In some preferred embodiments, as Figure 3 shown, the first bearing 41 and the second bearing 42 can be selected as ceramic angular contact bearings to improve the bearing's ability to withstand axial loads and extend the bearing life.

[0060] Furthermore, the main shaft 30 passes through the connecting flange 14 and is fixedly connected to the turbine 2. The stator assembly 33 is fixedly connected to the housing assembly. The first rotor assembly 31 and the second rotor assembly 32 are axially distributed on both sides of the stator assembly 33 and are both fixedly connected to the main shaft 30.

[0061] Figure 5 、 Figure 6 respectively show the exploded views of the dual-rotor disc motor 3 in some preferred embodiments. Figure 7 shows the structure of the iron core 332 in the stator assembly 33.

[0062] As Figure 5 shown in FIGS. 6 to 7, the outside of the stator assembly 33 is a fixed part 331 for fixedly connecting to the rear housing 13 and accommodating the iron core 332 and the coil windings inside. The iron core 332 can be made of a material such as silicon steel with high magnetic permeability and low hysteresis loss characteristics. On the side facing the first rotor assembly 31, a plurality of first tooth poles 3321 are formed that are circumferentially distributed and radially extended, and a plurality of first coil windings 3331 are wound thereon; similarly, on the side facing the second rotor assembly 32, a plurality of second tooth poles 3322 are formed that are circumferentially distributed and radially extended, and a plurality of second coil windings 3332 are wound thereon. Further, an isolation part 3323 with a certain axial thickness is formed between the first tooth poles 3321 and the second tooth poles 3322.

[0063] As Figure 5 、 6As shown, the first rotor assembly 31 includes an annular back plate 311, and a plurality of first N - pole magnets 3121 and first S - pole magnets 3122. Among them, the back plate 311 is sleeved on the main shaft 30 and fixedly connected to the main shaft 30. The first N - pole magnets 3121 and the first S - pole magnets 3122 are fixedly arranged on the side of the back plate 311 facing the stator assembly 33 and are arranged alternately along the circumferential direction. Correspondingly, the second rotor assembly 32 includes an annular back plate 321, and a plurality of second N - pole magnets 3221 and second S - pole magnets 3222. Among them, the back plate 321 is sleeved on the main shaft 30 and fixedly connected to the main shaft 30. The second N - pole magnets 3221 and the second S - pole magnets 3222 are fixedly arranged on the side of the back plate 321 facing the stator assembly 33 and are arranged alternately along the circumferential direction.

[0064] Each of the first coil windings 3331 and the second coil windings 3332 can be driven by alternating current or direct current, and the current directions in the first coil windings 3331 and the second coil windings 3332 are alternately changed through various known motor control methods, so as to realize the alternating change of the electromagnetic field polarity, and further drive the rotor assembly to drive the main shaft 30 to rotate relative to the housing. The working principle of the above - mentioned axial - flux motor is already known to those skilled in the art and will not be elaborated here.

[0065] When this high - speed motor is applied to the aeration system of aquaculture or other relatively humid environments, the temperature of the dual - rotor disc motor 3 will gradually increase during operation. Therefore, the water vapor inside the motor cavity will expand due to heat and be gradually discharged during the operation of the motor. However, in the shutdown state, as the temperature of the motor drops, the water vapor in the motor cavity will condense into water droplets and adhere to the surface of the inner cavity of the motor, resulting in a decrease in the internal electrical insulation of the motor and rusting of metal components such as bearings, thus reducing the service life of the motor. For this reason, in some preferred embodiments, as Figure 3 and Figure 4 shown, a skeleton oil seal 16 sleeved on the main shaft 30 is further provided on the side of the connecting flange 14 facing the volute 12 to seal the gap between the connecting flange 14 and the main shaft 30. In addition, in some other preferred embodiments, a sealing ring 15 is further provided on the side of the connecting flange 14 facing the rear housing 13. The sealing ring 15 is an annular elastic circle and is pre - buried in the annular groove on the connecting flange 14. During the assembly process of the volute 12, the connecting flange 14 and the rear housing 13, the sealing ring 15 is compressed, so as to realize the sealing of the gap between the connecting flange 14 and the rear housing 13. Through the above - mentioned skeleton oil seal 16 and the sealing ring 15, an effectively sealed motor cavity can be formed between the volute 12 and the rear housing 13, avoiding the problem that the humid water vapor enters the motor due to the negative pressure generated in the cavity where the motor is located relative to the external environment after shutdown.

[0066] When a fan with a turbine - volute structure is in operation, when the air flow passes through the impeller of the centrifugal fan, the curvature and angle design of the blades cause a pressure gradient of the air flow on the impeller, thereby generating aerodynamic force. Among them, the aerodynamic force along the axial direction from the rear housing 13 towards the air inlet 11 is called the axial aerodynamic force. Since the bearings sleeved on the main shaft 30 are positioned by structures such as the shaft shoulder of the main shaft 30, 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 force received by the bearings, accelerate their wear rate and affect their running stability.

[0067] Therefore, in the embodiment of the present application, the stator assembly 33 in the dual - rotor disc - type motor 3 and the two rotor assemblies on both sides thereof are arranged in a symmetric - split manner to actively generate an additional axial magnetic suction force for offsetting the axial aerodynamic force.

[0068] Specifically, in the embodiment of the present application, for each single - stator dual - rotor combination, the axial distance between the second rotor assembly 32 and the turbine 2 is greater than the axial distance between the first rotor assembly 31 and the turbine 2, that is, the second rotor assembly 32 is farther from the turbine 2 than the first rotor assembly 31. At the same time, the axial magnetic suction force F generated by the iron core 332 in the stator assembly 33 on the first N - pole magnet 3121 and the first S - pole magnet 3122 in the first rotor assembly 31 towards the rear housing 13 1 is greater than the axial magnetic suction force F generated by it on the second N - pole magnet 3221 and the second S - pole magnet 3222 in the second rotor assembly 32 towards the turbine 2 2 , so the stator assembly 33 will generate an axial magnetic suction force resultant force in a direction opposite to the axial aerodynamic force and with a magnitude of F 1 -F 2 on the two rotor assemblies. This axial magnetic suction force resultant force is further transmitted to the main shaft 30 through the two rotor assemblies, thereby effectively offsetting the axial load exerted by the axial aerodynamic force generated during the high - speed operation of the fan on the bearings, greatly delaying the wear rate of the bearings, and effectively increasing their running stability and service life.

[0069] A variety of implementation manners can be used to generate the above-mentioned resultant axial magnetic suction force. For example, in some preferred embodiments, the radial lengths of the first N-pole magnet 3121 and the first S-pole magnet 3122 can be set to be greater than the radial lengths of the second N-pole magnet 3221 and the second S-pole magnet 3222; in some other preferred embodiments, the radial dimension of the first tooth pole 3321 of the iron core 332 facing the first rotor assembly 31 can also be set to be greater than the radial dimension of the second tooth pole 3322 facing the second rotor assembly 32. The above manners can be implemented separately or jointly. Through the asymmetric setting manners of the above magnets and / or iron cores, the stator assembly 33 can always apply an axial magnetic suction force resultant to the two rotor assemblies, the direction of which is opposite to the axial aerodynamic force and the magnitude is F 1 -F 2 of the resultant axial magnetic suction force.

[0070] For another example, in some other preferred embodiments, the axial distance between the first N-pole magnet 3121 and the first S-pole magnet 3122 and the first tooth pole 3321 can also be set to be less than the axial distance between the second N-pole magnet 3221 and the second S-pole magnet 3222 and the second tooth pole 3322, and a resultant axial magnetic suction force opposite to the axial aerodynamic force is generated by adjusting the distance between the stator assembly 33 and the two rotor assemblies.

[0071] Figure 8 、 Figure 9 respectively show the situations of the axial forces received by the main shaft 30 when the dual-rotor disc-type high-speed fan is in a stationary state and at a certain moment during the acceleration process, Figure 10 and show a schematic diagram of the force-receiving situation of the shafting structure under the design working condition.

[0072] Through Figure 8 、 Figure 9 it can be seen that when the fan is in a stationary state, the axial aerodynamic force is zero, and at this time, there is only an axial magnetic suction resultant force to the right, which is transmitted from the main shaft 30 to the second bearing 42 (it should be noted that when there is a pre-tightening structure, the second bearing 42 is always also subjected to the pre-tightening force applied by the pre-tightening structure). However, since the main shaft 30 does not rotate at this time, there will be no 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 suction resultant force gradually reaches equilibrium, and the axial force acting on the second bearing 42 gradually decreases, thereby reducing the bearing wear problem caused by the large axial force during the rotation of the main shaft 30.

[0073] Furthermore, as Figure 10As shown, the axial magnetic attraction force can be set to be slightly less than the axial aerodynamic force of the fan under the design condition. That is, as the acceleration process continues, the resultant force of the axial magnetic attraction force and the axial aerodynamic force received by the second bearing 42 gradually decreases until they cancel each other out. When the rotational speed continues to increase, the axial aerodynamic force will exceed the axial magnetic attraction force, so that the resultant force of the two is to the left and is transmitted to the side of the first bearing 41 away from the turbine 2. Setting the value of the axial magnetic attraction force to be slightly less than the axial aerodynamic force corresponding to the design condition can enable the first bearing 41 to be within a reasonable axial force range during the long-term stable operation of the fan, while alleviating its frictional loss and ensuring the stable operation of the fan.

[0074] Figure 11 Some other preferred embodiments of the present application are shown, Figure 12 For Figure 11 the circle B in Figure 11 is enlarged and shown, as Figure 12 shown, an axial magnetic attraction force stabilizing mechanism 6 can be added between the first bearing 41 and the first rotor assembly 31, which is used to keep the difference between the axial magnetic attraction forces of the stator assembly 33 on the first rotor assembly 31 and the second rotor assembly 32 (i.e., F 1 -F 2 ) within the design range.

[0075] The reason for setting the axial magnetic attraction force stabilizing mechanism 6 between the first bearing 41 and the first rotor assembly 31 is that in order to ensure that the overall power of the fan reaches the design index, each N-pole magnet and S-pole magnet has strong magnetic characteristics. Therefore, the axial magnetic attraction forces F 1 , F 2 generated by the iron core of the stator assembly on the magnets of the rotor assemblies on both sides are much greater than the resultant axial magnetic attraction force F 1 -F 2 finally formed by the stator assembly on the two rotor assemblies (in some specific embodiments, the ratios of F 1 , F 2 to F 1 -F 2 are all about 10 times). Therefore, the resultant axial magnetic attraction force received by the two rotor assemblies is quite sensitive to the change in the axial position relative to the main shaft 30. That is, a slight deviation of the main shaft 30 along the axial direction relative to the design position may cause a large change in the resultant axial magnetic attraction force F 1 -F 2 received by the two rotor assemblies; however, there are assembly tolerances in the assembly process of the shafting structure. At the same time, during the acceleration process of the fan, as the axial aerodynamic force continuously increases and exceeds F 1 -F 2 , the main shaft 30 inevitably has a slight displacement in the direction of the turbine 2, which will cause the F1 rapidly decreases, and the F received by the second rotor assembly 32 2 rapidly increases, resulting in F 1 -F 2 shows a sharp drop, and further makes the cancellation effect of the resultant axial magnetic suction force on the axial aerodynamic force fail. Therefore, an axial magnetic suction force stabilizing mechanism is needed to prevent the main shaft 30 from displacing towards the turbine 2, so that it can generate a stable resultant axial magnetic suction force.

[0076] In some preferred embodiments, the axial magnetic suction force stabilizing mechanism 6 includes a compression spring 61 sleeved on the main shaft 30 and a spring retaining ring 62, where the spring retaining ring 62 is located at one end of the first bearing 41 facing away from the turbine 2, and the compression spring 61 is located between the spring retaining ring 62 and a spring blocking structure fixedly arranged on the main shaft 30 or the first rotor assembly 31.

[0077] The spring blocking structure can be implemented in various ways. For example, Figure 11 、 Figure 12 as shown, the side of the first rotor assembly 31 facing the first bearing 41 is used as the spring blocking structure. In addition, as shown in the embodiment of Figure 13 , a raised collar 301 can be added to the main shaft as the spring blocking structure.

[0078] Obviously, the length and elastic coefficient of the compression spring 61 should be precisely set so that it can correct the position of the rotor assembly only when the two rotor assemblies drive the main shaft 30 to have an unexpected displacement, resulting in the resultant axial magnetic suction force deviating too much from the design value. When the two rotor assemblies are in a reasonable position, additional elastic force between the rotor assembly and the first bearing 41 should be avoided as much as possible. For this purpose, in some preferred embodiments of the present application, when determining the length of the compression spring 61, the following constraint conditions are set for it: when the dual-rotor disc-type high-speed fan is in a stationary state, the elastic deformation force generated by the compression of the compression spring 61 by the spring retaining ring 62 and the spring blocking structure is less than a preset elastic deformation force threshold.

[0079] Specifically, the elastic deformation force threshold can be set much smaller than the resultant axial magnetic suction force F when the fan is in a stationary state 1 -F 2The value, that is, when the double-rotor disc high-speed fan is in a stationary state, the compression spring 61 only abuts slightly between the spring retaining ring 62 and the spring blocking structure without generating a significant elastic force on the rotor assembly or the main shaft 30; as the fan speed increases and the axial aerodynamic force increases, until the rotor assembly drives the main shaft 30 to axially displace towards the turbine 2, the compression amount of the compression spring 61 will correspondingly increase, and immediately generate an elastic force to resist the axial displacement to maintain the preset resultant axial magnetic suction force.

[0080] Obviously, the elastic coefficient of the compression spring 61 cannot be set too small, otherwise it may not be sufficient to resist the tendency of the two rotor assemblies to further displace towards the turbine 2 due to the reduction of the resultant axial magnetic suction force. In some preferred embodiments, such as Figure 14 shown, the elastic coefficient of the compression spring 61 can be determined by the following steps:

[0081] 810, apply a virtual displacement towards the turbine to the main shaft, and the magnitude of the virtual displacement does not exceed the relative displacement of the main shaft caused by the maximum axial aerodynamic force;

[0082] 820, calculate the resultant axial magnetic suction force on the main shaft when the virtual displacement occurs;

[0083] 830, determine the elastic coefficient of the compression spring based on the magnitude of the virtual displacement, the resultant axial magnetic suction force on the main shaft in the stationary state, and the resultant axial magnetic suction force on the main shaft when the virtual displacement occurs.

[0084] The above steps can be implemented by various force field simulation software known to those skilled in the art. Specifically, first apply a virtual displacement Δx to the main shaft 30, which represents the change in the rotor position that may be caused by the increase in the axial aerodynamic force, and then calculate the axial magnetic suction forces F 1 ' and F 2 ' of the stator assembly 33 on the first rotor assembly 31 and the second rotor assembly 32 when the virtual displacement occurs, so as to obtain the resultant axial magnetic suction force (F 1 '-F 2 ) at the virtual displacement position. Then, the elastic coefficient of the compression spring 61 can be determined by [(F 1 '-F 2 )-(F 1 -F 2 )] / Δx. This elastic coefficient is sufficient to ensure that when the main shaft 30 has a tendency to generate an undesired axial displacement, it can be kept in the designed position by applying an elastic force, thereby ensuring the generation of the desired resultant axial magnetic suction force.

[0085] This application also provides a design method for the above double-rotor disc high-speed fan, such as Figure 15As shown, in some preferred embodiments, the design method includes the following steps:

[0086] S1. Determine the design operating conditions of the dual-rotor disc-type high-speed blower based on the design specifications of the dual-rotor disc-type high-speed blower;

[0087] S2. Determine the specifications of the turbine and volute based on the design operating conditions, and the power range W when the dual-rotor disc-type high-speed blower reaches the design operating conditions Target ;

[0088] S3. Calculate the axial aerodynamic force F when the dual-rotor disc-type high-speed blower is in the design operating conditions P ;

[0089] S4. Based on F P determine the value range of the resultant axial magnetic suction force F Target , where the direction of F Target is opposite to the direction of F P ;

[0090] S5. Design the specification parameters of the stator assembly, the first rotor assembly, and the second rotor assembly such that when the dual-rotor disc-type high-speed blower is in a stationary state, the difference between the magnetic suction force F 1 of the stator assembly on the first rotor assembly and the magnetic suction force F 2 on the second rotor assembly satisfies F Target , and when the dual-rotor disc-type high-speed blower reaches the design operating conditions, the sum of the power W 1 of driving the first rotor assembly by the stator assembly and the power W 2 of driving the second rotor assembly by it satisfies W Target .

[0091] In some preferred embodiments, on the premise of meeting the total power requirement, multiple sets of single-stator dual-rotor combinations can also be set. By increasing the number of combinations, the power of each set of stator-rotor combinations can be correspondingly reduced, thereby achieving more precise adjustment of the axial magnetic suction force.

[0092] Further, in some preferred embodiments, the dual-rotor disc-type high-speed blower further includes an axial magnetic suction force stabilizing mechanism 6. The axial magnetic suction stabilizing mechanism includes a spring retainer 62 and a compression spring 61 sleeved on the main shaft 30. The design method of the dual-rotor disc-type high-speed blower further includes step S6: determining the length and elastic coefficient of the compression spring. The specific implementation manner of determining the axial magnetic suction force stabilizing mechanism 6 has been described above and will not be elaborated here.

[0093] The specific implementation manners of the present application have been described in detail above. For those skilled in the art of this technology, without departing from the principle of the present application, several improvements and modifications can still be made to the present application, and these improvements and modifications also fall within the protection scope of the claims of the present application.

Claims

1. A design method for a dual-rotor disc high-speed fan, the dual-rotor disc high-speed fan comprising a housing assembly and a turbine, a dual-rotor disc motor, and a bearing assembly arranged inside the housing assembly, The dual-rotor disc motor comprises a main shaft and at least one single-stator dual-rotor combination, wherein the main shaft is fixedly connected to the turbine, and the bearing assembly is sleeved between the main shaft and the housing assembly, and comprises a first bearing and a second bearing, wherein the axial distance between the first bearing and the turbine is smaller than the axial distance between the second bearing and the turbine; The single-stator dual-rotor combination comprises a first rotor assembly, a stator assembly, and a second rotor assembly which are sequentially sleeved on the main shaft along the axial direction; In each single-stator dual-rotor combination, its stator assembly is fixedly connected to the housing assembly, the axial distance between its second rotor assembly and the turbine is greater than the axial distance between its first rotor assembly and the turbine, and the axial magnetic attraction force of its stator assembly on its first rotor assembly is greater than the axial magnetic attraction force of its stator assembly on its second rotor assembly; It also includes an axial magnetic attraction stabilizing mechanism for maintaining the resultant axial magnetic attraction force on the main shaft within a designed range, wherein: The direction of the resultant axial magnetic attraction force is in the direction away from the turbine along the axial direction, and the magnitude is the difference between the axial magnetic attraction forces of the stator assembly on the first rotor assembly and the second rotor assembly; The axial magnetic attraction stabilizing mechanism comprises a compression spring and a spring retaining ring sleeved on the main shaft; the spring retaining ring is located at an end of the first bearing facing away from the turbine; the compression spring is located between the spring retaining ring and a spring retaining structure fixedly arranged on the main shaft or the first rotor assembly; The length of the compression spring is set to meet the following constraint condition: when the dual-rotor disc high-speed fan is in a stationary state, the elastic deformation force generated by the compression of the compression spring by the spring retaining ring and the spring blocking structure is less than a preset elastic deformation force threshold, wherein the elastic deformation force threshold is set to be much smaller than the value of the resultant axial magnetic attraction force when the fan is in a stationary state; The elastic coefficient of the compression spring is determined based on the following steps: applying a virtual displacement toward the turbine to the main shaft, the magnitude of the virtual displacement not exceeding the relative displacement of the main shaft caused by the maximum axial aerodynamic force; calculating the resultant axial magnetic attraction force on the main shaft when the virtual displacement occurs; determining the elastic coefficient of the compression spring based on the magnitude of the virtual displacement, the resultant axial magnetic attraction force on the main shaft in a stationary state, and the resultant axial magnetic attraction force on the main shaft when the virtual displacement occurs; It is characterized by comprising the following steps: Determining the design operating conditions of the dual-rotor disc high-speed fan based on the design indicators of the dual-rotor disc high-speed fan; Based on the design working condition, the specifications of the turbine and the volute are determined, and the power range W of the dual-rotor disc high-speed fan when it reaches the design working condition is determined. Target ; Calculate the axial aerodynamic force F of the dual-rotor disc high-speed fan under the design condition P ; Based on F P Determine the value range of the axial magnetic attraction force F Target , where F Target The direction of F P in the opposite direction; The specification parameters of the stator assembly, the first rotor assembly, and the second rotor assembly are designed so that when the dual-rotor disc high-speed fan is in a stationary state, the difference between the magnetic attraction force F1 of the stator assembly on the first rotor assembly and the magnetic attraction force F2 of the stator assembly on the second rotor assembly satisfies F Target , and when the dual-rotor disc high-speed fan reaches the design operating condition, the sum of the power W1 driven by the stator assembly to drive the first rotor assembly and the power W2 driven by the stator assembly to drive the second rotor assembly satisfies W Target .

2. The design method of a dual-rotor disc high-speed blower according to claim 1, characterized in that: The stator assembly comprises: An iron core, a plurality of groups of first coil windings and a plurality of groups of second coil windings; The multiple groups of first coil windings are arranged on the side of the iron core facing the turbine and are spaced apart along the circumferential direction, and the multiple groups of second coil windings are arranged on the side of the iron core facing away from the turbine and are spaced apart along the circumferential direction.

3. The design method of the dual-rotor disc high-speed blower according to claim 2 is characterized in that: The first rotor assembly includes a plurality of first N-pole magnets and first S-pole magnets facing the stator assembly, and each of the first N-pole magnets and first S-pole magnets is alternately arranged along the circumferential direction; The second rotor assembly includes a plurality of second N-pole magnets and second S-pole magnets facing the stator assembly, and each of the second N-pole magnets and second S-pole magnets is alternately arranged along the circumferential direction; The axial magnetic attraction force of the iron core on the first N-pole magnet and the first S-pole magnet is greater than the axial magnetic attraction force of the iron core on the second N-pole magnet and the second S-pole magnet.

4. The design method of a dual-rotor disc high-speed blower according to claim 3, characterized in that: The radial lengths of the first N-pole magnet and the first S-pole magnet are greater than the radial lengths of the second N-pole magnet and the second S-pole magnet, and / or the radial dimension of the iron core facing the turbine is greater than the radial dimension of the iron core facing away from the turbine.

5. The design method of a dual-rotor disc high-speed blower according to claim 3, characterized in that: An axial distance between the first N-pole magnet and the first S-pole magnet and the iron core is smaller than an axial distance between the second N-pole magnet and the second S-pole magnet and the iron core.

6. The design method of a dual-rotor disc high-speed blower according to claim 1, characterized in that: It also includes a pre-tightening structure, which elastically abuts between an end of the second bearing facing away from the turbine and the housing assembly.

7. The design method of a dual-rotor disc high-speed blower according to any one of claims 1 to 6, characterized in that: The housing assembly comprises an air inlet, a volute, a connecting flange and a rear housing which are fixedly connected in sequence along the axial direction, and the stator assembly is fixedly connected to the rear housing.

8. The design method of a dual-rotor disc high-speed blower according to claim 7, characterized in that: Also includes a skeleton oil seal and / or a sealing ring; The skeleton oil seal is arranged on the side of the connecting flange facing the volute, and is used to seal the gap between the connecting flange and the main shaft; The sealing ring is arranged on a side of the connecting flange facing the rear shell, and is used to seal the gap between the connecting flange and the rear shell.

9. The design method of a dual-rotor disc high-speed blower according to claim 1, characterized in that: An anti-creep O-ring is also sleeved between the retaining frame and the outer ring of the second bearing.

10. The design method of a dual-rotor disc high-speed blower according to claim 1, characterized in that: The number of the single-stator dual-rotor combinations is greater than or equal to one.

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