TW201739149A - Axial induction motor and axial induction fan - Google Patents

Abstract

An axial induction motor and an axial induction fan are disclosed. The axial induction motor comprises a stator, a rotor, and a metal ring. The stator includes a base, a shaft tube, a bearing and an exciting component. The shaft tube connects with the base and receives the bearing. The exciting component surrounds the shaft tube. The rotor includes a shaft and a magnet component. The shaft couples with the bearing such that it is able to rotate in the stator. The magnet component surrounds the shaft and the exciting component is aligned with the magnet component. The metal ring is mounted outside the shaft tube. At least a portion of the metal ring is aligned with the bearing in radial directions of the shaft.

Description

Axial induction motor and axial induction fan

The present invention relates to an axial induction motor and an axial induction fan, and more particularly to an axial induction motor having a metal ring on the outer circumference of the shaft tube, and an axial induction fan provided with the axial induction motor.

Referring to FIG. 1 , a conventional axial induction motor 9 includes a stator 91 having a shaft tube 911. The shaft tube 911 is provided with a bearing 912 for rotating a rotor 92. Combine. A magnet 921 is disposed on the inner side of the rotor 92 to cause a magnetic interlinking between the coil 913 of the stator 91 and the magnet 921 to drive the rotor 92 to rotate. An embodiment of the conventional axial induction motor 9 has been disclosed in the "Thin Heat Dissipation Mechanism" patent of Chinese Patent No. 200610072272.8.

Wherein, the shaft tube 911 is made of a plastic material, and the bearing 912 is made of a metal material. Since the thermal expansion coefficient of the plastic material is usually larger than the thermal expansion coefficient of the metal material (for example, the linear thermal expansion coefficient of polyvinyl chloride is 80.0 (10 ^-6 / ° C), and the copper is 17.5 (10 ^-6 / ° C)), so when the axis When the induction motor 9 is operated or heated by external conditions, the volume variation of the shaft tube 911 will be greater than that of the bearing 912. This causes the bearing 912 to be unable to be firmly coupled to the shaft tube 911, thereby adversely affecting the rotational balance of the rotor 92.

In detail, the coil 913 of the stator 91 of the axial induction motor 9 is opposed to the magnet 921 of the rotor 92 in the axial direction, and therefore the magnet 921 necessarily contains a component in the axial direction when subjected to a force. If the bearing 912 cannot be firmly coupled to the shaft tube 911, the magnet 921 bears the shaft. The upward component force will cause the bearing 912 to loosen, causing the rotor 92 to be unbalanced when it is rotated, which may cause noise or vibration when the axial induction motor 9 is operated.

In view of this, there is a need to provide a further improved axial induction motor to improve the rotational balance of the axial induction motor and the axial induction fan.

SUMMARY OF THE INVENTION One object of the present invention is to provide an axial induction motor and a fan with a metal ring disposed on the outer circumference of a shaft tube of a stator to limit the amount of radial deformation of the shaft tube.

In order to achieve the foregoing object, the technical means for the present invention include: an axial induction motor comprising: a stator having a base, a shaft tube, a bearing and an excitation component, the shaft tube being disposed on the base, a bearing is disposed in the shaft tube, the excitation component is disposed around the shaft tube; a rotor has a rotating shaft and a magnet assembly coupled to the bearing for rotation relative to the stator, the magnet assembly surrounding the rotating shaft and The excitation component is aligned; and a metal ring is disposed on the outer circumference of the shaft tube, and at least a portion of the inner circumferential surface of the metal ring is aligned with the bearing in a radial direction of the rotation shaft.

The excitation component of the stator is disposed on a circuit board, and the circuit board is fixed to the base, and the metal ring is located on a side of the circuit board facing away from the base. Thereby, the metal ring does not affect the routing of the circuit board or cause interference to electronic components on the circuit board.

Wherein the metal ring is composed of a magnetically permeable material, and at least a portion of the outer circumferential surface of the metal ring is aligned with the magnet assembly in a radial direction of the rotating shaft. Thereby, the metal ring and the magnet assembly can generate a magnetic attraction effect in the radial direction of the rotating shaft, so that the rotating shaft can be stably rotated, thereby achieving the effect of improving the rotational balance of the rotor.

Wherein the outer surface of the metal ring is provided with a flange having a suction surface facing the magnet assembly. Thereby, the flange can shorten the distance between the metal ring and the magnet assembly to generate a better magnetic attraction effect with the magnet assembly via the attraction surface.

Wherein the flange is adjacent to the side of the magnet assembly and further forms a ring lip, the attraction The face is the surface of the ring lip facing the magnet assembly. Thereby, the ring lip can increase the range of magnetization of the metal ring affected by the magnet assembly, so that the metal ring and the magnet assembly can produce a better magnetic attraction effect.

Wherein the outer circumference of the shaft tube forms a support surface, the support surface faces away from the base, and the support surface supports the metal ring. Thereby, the supporting surface can enhance the bonding strength between the metal ring and the shaft tube to prevent the metal ring from slipping off from the shaft tube in a low temperature environment.

The thermal expansion coefficient of the metal ring and the bearing is smaller than the thermal expansion coefficient of the shaft tube. Thereby, the metal ring can limit the amount of radial deformation of the shaft tube when the axial induction motor heats up.

Wherein the metal ring has a thermal expansion coefficient of 0.5 to 1.5 times the thermal expansion coefficient of the bearing. Thereby, the metal ring and the volume of the bearing are changed by the influence of temperature, which ensures that the metal ring effectively limits the radial deformation of the shaft tube without excessively pressing the shaft tube.

The material of the bearing is metal, and the material of the shaft tube is plastic to reduce the manufacturing cost and the process difficulty of the motor.

Wherein the outer diameter of the shaft tube is greater than the inner diameter of the metal ring before the shaft tube and the metal ring are assembled with each other. Thereby, when the metal ring is disposed on the outer circumference of the shaft tube, the metal ring can form a tight fit with the shaft tube.

The combination of the metal ring and the shaft tube is an injection coating bond, so that the metal ring and the shaft tube can be closely adhered.

The rotor further has a magnetic member disposed on a side of the magnet assembly away from the excitation component. Thereby, the magnetic sealing member can provide a magnetic action to the magnet assembly and concentrate the magnetic force of the magnet assembly to increase its magnetic flux density.

The rotor includes a housing, the shaft is coupled to the housing, and one surface of the magnetic sealing member is coupled to the housing, and the other surface of the magnetic sealing member is coupled to the magnet assembly. Thereby, the magnetic sealing component and the excitation component can be respectively located on two sides of the magnet component, so that the magnetic sealing component can The magnet assembly is provided with a magnetic sealing effect.

Wherein the magnetic sealing member is coupled to the rotating shaft. Thereby, the foregoing housing is not required to be additionally provided, and the magnetic sealing member and the excitation assembly are respectively located on both sides of the magnet assembly, so that the magnetic sealing member can provide a magnetic sealing function.

Wherein the shaft tube has an opening through which the shaft extends, the metal ring being adjacent to the opening and away from the base. Thereby, since the portion of the shaft tube adjacent to the opening has a large deformation margin, the metal ring can be prevented from restricting the radial deformation of the shaft tube, and the pressure acting on the shaft tube is excessively caused to cause the shaft tube to be broken.

The excitation component of the stator is disposed on a circuit board, the circuit board is fixed to the base, and a gap is formed between the circuit board and the shaft tube, and the metal ring extends into the gap. Thereby, the metal ring can be formed between the circuit board and the shaft tube, so that the metal ring can completely cover the shaft tube to enhance the effect of the metal ring limiting the radial deformation of the shaft tube.

An axial induction fan is provided with an axial induction motor as described above, and further comprises: a plurality of blades, each of which can be disposed on the outer circumference of the rotating shaft of the rotor, the casing or the magnetic sealing member. Thereby, the rotor can be driven by the blades to generate an air flow when the rotor rotates.

According to the foregoing structure, the axial induction motor and the fan of the embodiments of the present invention can restrict the radial deformation of the shaft tube by the metal ring when the axial induction motor is heated by the metal ring provided on the outer circumference of the shaft tube. The amount of the bearing can be firmly integrated into the shaft tube to improve the rotational balance of the rotor under varying temperature conditions. Furthermore, the metal ring of the axial induction motor and the fan of some embodiments of the present invention is composed of a magnetically permeable material, and at least a portion of the outer circumferential surface of the metal ring is aligned with the magnet assembly in the radial direction of the rotating shaft, so that The metal ring and the magnet assembly are capable of generating a magnetic attraction effect in the radial direction of the rotating shaft, so that the rotating shaft can be stably rotated, thereby achieving the effect of improving the rotational balance of the rotor.

〔this invention〕

1‧‧‧stator

11‧‧‧Base

12‧‧‧ shaft tube

121‧‧‧Support surface

122‧‧‧ openings

13‧‧‧ Bearing

14‧‧‧Exciting components

15‧‧‧Circuit board

2‧‧‧Rotor

21‧‧‧ shaft

22‧‧‧ Magnet assembly

23‧‧‧Magnetic parts

24‧‧‧Shell

3‧‧‧Metal ring

3a‧‧‧ inner circumference

3b‧‧‧ outer perimeter

31‧‧‧Flange

311‧‧‧Attraction

312‧‧‧ Ring Lips

4‧‧‧ leaves

G‧‧‧ gap

[study]

9‧‧‧Axial induction motor

91‧‧‧ Stator

911‧‧‧ shaft tube

912‧‧‧ bearing

913‧‧‧ coil

92‧‧‧Rotor

921‧‧‧ magnet

Fig. 1 is a cross-sectional view showing the structure of a conventional axial induction motor.

Fig. 2 is a cross-sectional view showing the structure of an axial induction motor according to a first embodiment of the present invention.

Fig. 3 is a cross-sectional view showing the structure of an axial induction motor according to a second embodiment of the present invention.

Fig. 4 is a cross-sectional view showing the structure of an axial induction motor according to a third embodiment of the present invention.

Fig. 5 is a cross-sectional view showing the structure of an axial induction motor according to a fourth embodiment of the present invention.

Figure 6 is a cross-sectional view showing the structure of an axial induction motor according to a fifth embodiment of the present invention.

The above and other objects, features and advantages of the present invention will become more <RTIgt; An axial induction motor according to a first embodiment of the present invention comprises a stator 1, a rotor 2 and a metal ring 3. The rotor 2 is rotatably coupled to the stator 1, and the metal ring 3 is provided to the stator 1.

The stator 1 has a base 11, a shaft tube 12, a bearing 13 and an excitation assembly 14. The shaft tube 12 is disposed on the base 11 , and the shaft tube 12 and the base 11 can be integrally formed. The bearing 13 is received in the shaft tube 12, and the bearing 13 can be coupled to the shaft tube 12 by a tight fit or a press fit. The excitation assembly 14 is disposed around the shaft tube 12, and the excitation assembly 14 can include an element such as a coil that is capable of generating an alternating magnetic field. The material of the bearing 13 is metal, and the material of the shaft tube 12 is plastic to reduce the manufacturing cost and the process difficulty of the motor.

The rotor 2 has a rotating shaft 21 and a magnet assembly 22 rotatably coupled to the bearing 13 for rotation relative to the stator 1. The magnet assembly 22 surrounds the rotating shaft 21, and the magnet assembly 22 is on the rotating shaft 21 Abutting the excitation assembly 14 in the axial direction enables an axial air gap to be formed between the magnet assembly 22 and the excitation assembly 14.

The metal ring 3 is disposed on the outer circumference of the shaft tube 12, and the metal ring 3 includes a pair of inner circumferential surfaces 3a and an outer circumferential surface 3b, and the inner circumferential surface 3a faces the shaft tube 12. In the radial direction of the rotary shaft 21, at least a portion of the inner circumferential surface 3a of the metal ring 3 is aligned with the bearing 13. this In addition, the excitation component 14 of the stator 1 can be disposed on a circuit board 15, and the circuit board 15 can be fixed to the base 11. The metal ring 3 is preferably located on a side of the circuit board 15 facing away from the base 11. Thereby, the metal ring 3 does not affect the routing of the circuit board 15 or cause interference to the electronic components on the circuit board 15.

With the above structure, when the axial induction motor of the first embodiment of the present invention is actually used, the excitation assembly 14 can generate an alternating magnetic field to generate magnetic interference with the magnet assembly 22, so that the rotor 2 can be opposed to the stator. 1 rotation.

The metal ring 3 and the material of the bearing 13 are both metal, and it can be seen that when the axial induction motor is heated due to operation or external conditions, even if the volume change of the shaft tube 12 is larger than the bearing 13, Since the metal ring 3 is disposed on the outer circumference of the shaft tube 12, and the volume change range of the metal ring 3 is similar to that of the bearing 13, the metal ring 3 can effectively limit the radial deformation amount of the shaft tube 12, so that The bearing 13 can be firmly coupled in the shaft tube 12. In other words, the bearing 13 is not loosened by the influence of thermal expansion, so the rotor 2 can maintain a good rotational balance under varying temperature conditions.

Furthermore, in the present embodiment, the metal ring 3 may be selected from a magnetically permeable material, and at least a portion of the outer peripheral surface 3b of the metal ring 3 is aligned with the magnet assembly 22 in the radial direction of the rotating shaft 21. Thereby, a magnetic attraction effect can be generated between the metal ring 3 and the magnet assembly 22 to further improve the rotational balance of the rotor 2. More specifically, the magnet assembly 22 forms a plurality of magnetic poles (N pole or S pole) on a side adjacent to the excitation component 14 and away from the other side of the excitation component 14 , and the outer circumferential surface 3 b of the metal ring 3 At least a portion of the magnet assembly 22 is preferably positioned opposite the portion of the magnet assembly 22 adjacent the magnetic poles such that the metal ring 3 can be magnetized and create a mutually attractive force with the magnet assembly 22. Accordingly, the metal ring 3 and the magnet assembly 22 can generate a magnetic attraction effect in the radial direction of the rotating shaft 21, so that the rotating shaft 21 can be stably rotated, thereby achieving the effect of improving the rotational balance of the rotor 2.

According to the foregoing technical concept, the airflow switching device of the embodiment of the present invention is enumerated in detail below. The various features are described one by one. Referring to FIG. 2, in the axial induction motor of the first embodiment, the outer surface of the metal ring 3 is provided with a flange 31 along which the flange 31 is located. The shaft 21 extends radially outward, and the flange 31 has a suction surface 311 facing the magnet assembly 22. Thereby, the flange 31 can shorten the distance between the metal ring 3 and the magnet assembly 22, thereby generating a better magnetic attraction effect with the magnet assembly 22 via the attraction surface 311, and ensuring that the rotation shaft 21 can be stably rotated.

Referring to FIG. 3, an axial induction motor according to a second embodiment of the present invention is different from the first embodiment in that the flange 31 is formed adjacent to the side of the magnet assembly 22 to form a ring lip. 312, the ring lip portion 312 extends along the axial direction of the rotating shaft 21, and the attracting surface 311 is the surface of the ring lip portion 312 facing the magnet assembly 22. Thereby, the ring lip portion 312 can increase the range of magnetization of the metal ring 3 by the magnet assembly 22, so that the metal ring 3 and the magnet assembly 22 can produce a better magnetic attraction effect, ensuring that the rotating shaft 21 can Rotate steadily.

Referring to FIG. 4, an axial induction motor according to a third embodiment of the present invention is different from the foregoing first embodiment in that a peripheral surface 12 defines a support surface 121, and the support surface 121 can be It is a surface formed on one shoulder of the outer circumference of the shaft tube 12, and the support surface 121 may be in the form of a plane, a slope or a curved surface, etc., and the invention is not limited thereto. The support surface 121 faces away from the base 11 , and the support surface 121 supports the metal ring 3 . Thereby, the supporting surface 121 can enhance the bonding strength between the metal ring 3 and the shaft tube 12 to prevent the metal ring 3 from slipping off from the shaft tube 12 in a low temperature environment.

On the other hand, although in the foregoing first and second embodiments, the exciting assembly 14 includes a winding coil (for example, a coreless coil winding) for generating an alternating magnetic field, but in the present embodiment, the exciting The assembly 14 can include a coil formed directly on the circuit board 15, which can be fabricated by wiring such as printing or electroforming, and can also generate an alternating magnetic field, and can further reduce the axial height of the axial induction motor.

It should be noted that the metal ring 3 and the material of the bearing 13 are both metal. The material of the shaft tube 12 is plastic, so the coefficient of thermal expansion of the metal ring 3 and the bearing 13 is smaller than the thermal expansion coefficient of the shaft tube 12, so that the metal ring 3 can limit the shaft tube when the axial induction motor is warmed up. The amount of radial deformation of 12. In order to ensure that the metal ring 3 effectively limits the radial deformation amount of the shaft tube 12 without excessively pressing the shaft tube 12, the metal ring 3 and the bearing 13 are preferably made of the same material or materials having similar thermal expansion coefficients. Therefore, the present invention preferably has a coefficient of thermal expansion of the metal ring 3 of 0.5 to 1.5 times the coefficient of thermal expansion of the bearing 13. Thereby, the metal ring 3 and the volume of the bearing 13 are changed by the influence of temperature, so as to ensure that the metal ring 3 effectively limits the radial deformation amount of the shaft tube 12 without excessively pressing the shaft tube 12.

In the embodiments of the present invention, before the shaft tube 12 and the metal ring 3 are assembled with each other, the outer diameter of the shaft tube 12 may be larger than the inner diameter of the metal ring 3, so that the metal ring 3 is disposed on the shaft tube 12. At the outer circumference, the metal ring 3 can form a tight fit with the shaft tube 12. Alternatively, the metal ring 3 and the shaft tube 12 may be combined by injection coating to cover the inner circumferential surface 3a of the metal ring 3 by injection molding, so that the metal ring 3 and The shaft tube 12 can be closely fitted.

Referring to Figures 2, 3 and 4, in the embodiments of the present invention, the rotor 2 further has a magnetic member 23, the magnetic sealing member 23 is made of a magnetic conductive material, and the magnetic sealing member 23 is The magnet assembly 22 is disposed away from one side of the excitation assembly 14. In detail, the rotor 2 may include a casing 24, the rotating shaft 21 is coupled to the casing 24, and one surface of the magnetic sealing member 23 is coupled to the casing 24, and the other surface of the magnetic sealing member 23 is The magnet assembly 22 is provided. The magnet assembly 22 can directly join the other surface of the magnetic sealing member 23, or the magnet assembly 22 can also be indirectly coupled to the other surface of the magnetic sealing member 23 via a buffer member or the like. Thereby, the magnetic sealing member 23 and the excitation component 14 can be respectively located on two sides of the magnet assembly 22, so that the magnetic sealing member 23 can provide a magnetic action to the magnet assembly 22, and concentrate the magnetic force of the magnet assembly 22. To increase its magnetic flux density.

Wherein, when the axial induction motor of each embodiment is to be applied to an axial induction wind In the case of a fan, a plurality of blades 4 may be provided on the outer circumference of the rotating shaft 21 of the rotor 2. Since the rotating shaft 21 is coupled to the housing 24 in the above embodiments, each of the blades 4 may be disposed on the outer circumference of the housing 24, and each of the blades 4 may be integrally formed with the housing 24, the rotor 2, the rotor 2 The stator 1, the metal ring 3 and each of the blades 4 may together constitute the axial induction fan. Each of the blades 4 and the rotor 2 serves as a fan of the axial induction fan, so that when the rotor 2 rotates, each of the blades 4 can be used to drive air to generate an air flow.

Although in the foregoing embodiments, the magnetic sealing member 23 is coupled to the housing 24, please refer to FIG. 5, which is an axial induction motor according to a fourth embodiment of the present invention, and the foregoing embodiments. The difference is that the magnetic sealing member 23 can be directly coupled to the rotating shaft 21, so that the housing 24 is not required to be additionally disposed, and the magnet assembly 22 is disposed on a side surface of the magnetic sealing member 23 facing the exciting assembly 14. Similarly, the magnet assembly 22 can directly join one side surface of the magnetic sealing member 23, or the magnet assembly 22 can also be indirectly coupled to one side surface of the magnetic sealing member 23 via a cushioning member or the like. Thereby, the magnetic sealing member 23 and the excitation component 14 are respectively located on both sides of the magnet assembly 22, so that the magnetic sealing member 23 can provide a magnetic sealing effect. Wherein, the magnetic sealing member 23 is made of a magnetic conductive material, and the rotating shaft 21 is generally made of a metal material, so that the magnetic sealing member 23 and the rotating shaft 21 can be combined with each other by laser welding, so that the magnetic sealing member 23 and the magnetic sealing member 23 The shaft 21 can have a better bond stability.

When the axial induction motor of the fourth embodiment is to be applied to an axial induction fan, the outer periphery of the magnetic sealing member 23 of the rotor 2 may be provided with a plurality of blades 4, each of which can be coupled to the sealing member by injection molding. The magnetic member 23, the rotor 2, the stator 1, the metal ring 3 and the respective blades 4 can together constitute the axial induction fan, so that when the rotor 2 rotates, each of the blades 4 can also be used to generate airflow.

Referring to FIG. 6, an axial induction motor according to a fifth embodiment of the present invention is different from the foregoing embodiments in that a gap G is formed between the circuit board 15 and the shaft tube 12, and the metal The ring 3 can extend into the gap G such that the metal ring 3 is located on the circuit board 15 Between the shaft tubes 12. Thereby, the metal ring 3 can completely cover the shaft tube 12 to enhance the effect of the metal ring 3 limiting the amount of radial deformation of the shaft tube 12.

In the axial induction motor of various embodiments of the present invention, the shaft tube 12 may have an opening 122 through which the shaft 21 extends to form a rotatably coupled bearing 13. The metal ring 3 is adjacent to the opening 122 and away from the base 11 . Therefore, since the portion of the shaft tube 12 adjacent to the opening 122 has a large deformation margin, by disposing the metal ring 3 on a portion of the shaft tube 12 adjacent to the opening 122, the metal ring 3 can be prevented from restricting the shaft. The amount of radial deformation of the tube 12 is excessively applied to the shaft tube 12, causing the shaft tube 12 to rupture.

In summary, the axial induction motor of each embodiment of the present invention can fix the diameter of the shaft tube 12 with the metal ring 3 when the axial induction motor is warmed up by the outer circumference of the shaft tube 12. The amount of deformation is such that the bearing 13 can be firmly coupled in the shaft tube 12. Compared with the bearing 912 of the prior art axial induction motor 9, it is easy to loosen in the shaft tube 911 when the temperature rises, so that the rotor 92 can not be balanced when it is rotated, and the axial induction motor of the embodiments of the present invention can actually lift the rotor 2 Rotational balance under varying temperature conditions to avoid problems such as noise or vibration when the axial induction motor is running.

Furthermore, since the metal ring 3 can be selected from a magnetically permeable material, and at least a portion of the outer peripheral surface 3b of the metal ring 3 is aligned with the magnet assembly 22 in the radial direction of the rotating shaft 21, the metal ring 3 is A magnetic attraction effect can be generated between the magnet assemblies 22, so that the rotating shaft 21 can be stably rotated to further improve the rotational balance of the rotor 2.

While the invention has been described in connection with the preferred embodiments described above, it is not intended to limit the scope of the invention. The technical scope of the invention is protected, and therefore the scope of the invention is defined by the scope of the appended claims.

1‧‧‧stator

11‧‧‧Base

12‧‧‧ shaft tube

122‧‧‧ openings

13‧‧‧ Bearing

14‧‧‧Exciting components

15‧‧‧Circuit board

2‧‧‧Rotor

21‧‧‧ shaft

22‧‧‧ Magnet assembly

23‧‧‧Magnetic parts

24‧‧‧Shell

3‧‧‧Metal ring

3a‧‧‧ inner circumference

3b‧‧‧ outer perimeter

31‧‧‧Flange

311‧‧‧Attraction

4‧‧‧ leaves

Claims (19)

An axial induction motor comprising: a stator having a base, a shaft tube, a bearing and an excitation component, the shaft tube being disposed on the base, the bearing being received in the shaft tube, the excitation component surrounding the shaft tube a rotor having a rotating shaft coupled to the bearing for rotation relative to the stator, the magnet assembly surrounding the rotating shaft and aligned with the exciting assembly, and a metal ring disposed on the shaft tube The outer circumference, and in the radial direction of the rotating shaft, at least a portion of the inner circumferential surface of the metal ring is aligned with the bearing. The axial induction motor of claim 1, wherein the excitation component of the stator is disposed on a circuit board, the circuit board is fixed to the base, and the metal ring is located on a side of the circuit board facing away from the base. The axial induction motor of claim 1, wherein the metal ring is made of a magnetically permeable material, and at least a portion of an outer circumferential surface of the metal ring is aligned with the magnet assembly in a radial direction of the rotating shaft. The axial induction motor of claim 1, wherein the outer surface of the metal ring is provided with a flange having a suction surface facing the magnet assembly. The axial induction motor of claim 4, wherein a side of the flange adjacent to the magnet assembly further forms a ring lip, the suction surface being a surface of the ring lip facing the magnet assembly. The axial induction motor of claim 1, wherein the outer circumference of the shaft tube forms a support surface, the support surface faces away from the base, and the support surface supports the metal ring. The axial induction motor of claim 1, wherein the metal ring and the bearing have a thermal expansion coefficient smaller than a thermal expansion coefficient of the shaft tube. The axial induction motor of claim 7, wherein the metal ring has a thermal expansion coefficient of 0.5 to 1.5 times a thermal expansion coefficient of the bearing. The axial induction motor of claim 1, wherein the material of the bearing is metal, and the material of the shaft tube is plastic. The axial induction motor of claim 1, wherein the outer diameter of the shaft tube is greater than the inner diameter of the metal ring before the shaft tube and the metal ring are assembled with each other. The axial induction motor of claim 1, wherein the combination of the metal ring and the shaft tube is an injection coating. The axial induction motor of claim 1, wherein the rotor further has a magnetic member disposed on a side of the magnet assembly away from the excitation component. The axial induction motor of claim 12, wherein the rotor comprises a housing, the shaft is coupled to the housing, and a surface of the magnetic sealing member is coupled to the housing, the magnetic sealing member The other surface is for bonding the magnet assembly. The axial induction motor of claim 12, wherein the magnetic sealing member is coupled to the rotating shaft. The axial induction motor of claim 1, wherein the excitation component of the stator is disposed on a circuit board, the circuit board is fixed to the base, and a gap is formed between the circuit board and the shaft tube. A metal ring extends into the gap. The axial induction motor of claim 1, wherein the shaft tube has an opening through which the shaft extends, the metal ring being adjacent to the opening and away from the base. An axial induction fan provided with an axial induction motor as described in claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 15 or 16 The method includes: a plurality of blades, each of the blades being disposed on an outer circumference of the rotating shaft of the rotor. An axial induction fan is provided with an axial induction motor according to claim 13 of the patent application, and further comprising: a plurality of blades, each of the blades being disposed on an outer circumference of the casing of the rotor. An axial induction fan is provided with an axial induction horse as described in claim 14 And further comprising: a plurality of blades, each of the blades being disposed on an outer circumference of the magnetic sealing member of the rotor.