Outer rotor fan

Abstract

The invention relates to an outer rotor fan. The outer rotor fan comprises a stator plastic package assembly and a rotor plastic package assembly. The plastic package body, the winding stator and the shaft core are subjected to integral injection molding to form the stator plastic package assembly, and the fan blade rotor and the magnetic ring are subjected to integral injection molding to form the rotor plastic package assembly, so that the production procedures can be reduced, the assembly difficulty can be reduced, and the assembly efficiency can be improved; according to the technical scheme, the wind wheel and the outer rotor are integrated components, split design in the prior art is not needed, the phenomenon of dynamic unbalance superposition after the wind wheel and the rotor are installed in the prior art is avoided, the dynamic unbalance amount is reduced, noise generated in the working process of the fan is reduced, the integration degree is improved, and assembling is convenient.

Description

Technical Field

[0001] The present invention relates to the technical field of fans, and in particular to an outer rotor fan. Background Art

[0002] The air supply fan in a gas water heater typically consists of a volute and a drive motor. The drive motor is mounted on the outer wall of the volute, which is equipped with an air inlet and outlet. The drive motor includes a stator, a rotor, and an output shaft. One end of the output shaft extends into the volute and is detachably connected to a centrifugal impeller.

[0003] Since the centrifugal fan wheel and the rotor of the drive motor belong to different rotating components, after being assembled into an air supply fan, the centrifugal fan wheel has dynamic imbalance and the rotor also has dynamic imbalance. The dynamic imbalance of the two rotating components is superimposed, which can easily cause the fan to vibrate and generate noise. Summary of the Invention

[0004] The present invention provides an outer rotor fan, which can reduce the noise generated by the fan due to vibration.

[0005] The above technical problems are solved by the following technical solutions:

[0006] An external rotor fan includes a stator plastic packaging assembly and a rotor plastic packaging assembly. The stator plastic packaging assembly includes an integrally injected plastic packaging body, a wound stator and a shaft core. The wound stator and the shaft core are arranged on the plastic packaging body, and the wound stator is evenly arranged around the shaft core in the circumferential direction; the rotor plastic packaging assembly includes an integrally injected fan blade rotor and a magnetic ring. The fan blade rotor is rotatably connected to the shaft core, and the magnetic ring is arranged around the periphery of the wound stator.

[0007] The outer rotor fan described in the present invention has the following beneficial effects compared with the background technology: by integrally injecting the plastic package body, the winding stator and the shaft core to form a stator plastic package assembly, and integrally injecting the fan blade rotor and the magnetic ring to form a rotor plastic package assembly, the integration is improved and the assembly difficulty is reduced. At the same time, because the fan blade rotor and the magnetic ring are integrally injected to form the rotor plastic package assembly, the wind wheel and the outer rotor are an integrated component, and there is no need for a split design like in the existing solution, thereby avoiding the phenomenon of dynamic imbalance superposition after the wind wheel and the outer rotor are installed in the existing solution, reducing the dynamic imbalance amount, and thus reducing the noise generated during the operation of the fan.

[0008] In one embodiment, the fan rotor is provided with a bearing, and the bearing includes an upper bearing and a lower bearing, and the upper bearing and the lower bearing are both sleeved on the shaft core.

[0009] In one embodiment, the interior of the plastic-sealed body is provided with an inner cavity with an open end, and the shaft core includes an exposed end of the shaft core located in the inner cavity and extending outward along the opening of the inner cavity; the fan rotor is provided with an inner circumferential wall with one end extending into the inner cavity, and the upper bearing and the lower bearing are both arranged on the inner circumferential wall.

[0010] In one embodiment, the interior of the inner circumferential wall is formed with an upper bearing chamber and a lower bearing chamber arranged around the exposed end of the shaft core, the upper bearing chamber and the lower bearing chamber are arranged at intervals along the axial direction of the exposed end of the shaft core, the upper bearing is arranged in the upper bearing chamber, and the lower bearing is arranged in the lower bearing chamber.

[0011] The outer rotor fan described in the present invention has the following beneficial effects: by providing an injection-molded plastic-encapsulated rotor with an upper bearing chamber and a lower bearing chamber arranged around the exposed end of the shaft core, the concentricity of the two bearing chambers is improved. When the two bearings are placed in the two bearing chambers for operation, the vibration and friction of the two bearings during operation can be reduced due to the high concentricity of the two bearings, thereby reducing the noise during the operation of the fan.

[0012] In one embodiment, the inner cavity is provided with a lower sleeve for abutting against the bearing inner ring of the lower bearing.

[0013] In one embodiment, both the upper bearing and the lower bearing are ball bearings.

[0014] In one embodiment, it also includes a volute, which has a ventilation duct and an installation port, and the installation port is connected to the ventilation duct; the plastic-sealed body includes a mounting plate and a plastic-sealed main body, and the mounting plate can be detachably installed on the mounting port, the winding stator is arranged on the plastic-sealed main body, and the plastic-sealed main body and the rotor plastic-sealed assembly are located in the ventilation duct.

[0015] The external rotor fan described in the present invention has the following beneficial effects: by using the mounting plate to be disassembled and installed at the mounting opening of the volute to enclose a cavity with a ventilation duct, the wound stator, the plastic-sealed main body and the rotor plastic-sealed assembly are arranged in the ventilation duct, and there is no need to set up a separate motor installation space outside the volute, thereby reducing the axial size of the external rotor motor as a whole in the shaft core, and thus reducing the overall volume of the external rotor fan.

[0016] In one embodiment, an upper sleeve is provided on the volute, and the upper sleeve is sleeved on the outer periphery of the exposed end of the shaft core. An elastic member is provided between the upper sleeve and the inner ring of the upper bearing.

[0017] The external rotor fan described in the present invention has the following beneficial effects: by adding an upper sleeve to the volute, which is used to be sleeved on the outer periphery of the exposed end of the shaft core, since the shaft core is passed through the inner cavity, the shaft core can be supported at two points, making the shaft core more reliable after installation; and by arranging the elastic member between the upper sleeve and the inner ring of the ball bearing of the upper bearing, the elastic member has the ability to provide pre-pressure for the two bearings, thereby pressing the two bearings.

[0018] In one embodiment, the volute is provided with an air inlet connected to the ventilation duct, the fan rotor includes a plastic-sealed rotor, a plastic-sealed wind wheel, and a plastic-sealed bridging section integrally connected between the plastic-sealed rotor and the plastic-sealed wind wheel, and the plastic-sealed rotor, the plastic-sealed bridging section and the plastic-sealed wind wheel form an air inlet cavity that is recessed away from the air inlet; the magnetic ring is arranged on the plastic-sealed rotor.

[0019] In one embodiment, the magnetic ring includes at least one group of N-pole magnetic steel and S-pole magnetic steel, and the N-pole magnetic steel and the S-pole magnetic steel are staggered along the circumferential direction. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0021] Figure 1 A cross-sectional view of the outer rotor blower provided by the present invention;

[0022] Figure 2 A cross-sectional view of a stator plastic package assembly in an external rotor blower provided by the present invention;

[0023] Figure 3 A cross-sectional view of a rotor plastic package assembly in an external rotor blower provided by the present invention;

[0024] Figure 4 A cross-sectional view of a volute in an external rotor blower provided by the present invention;

[0025] Figure 5 This is a top view of the volute in the external rotor blower provided by the present invention.

[0026] Description of reference numerals:

[0027] 1. Stator plastic package assembly; 11. Plastic package body; 111. Inner cavity; 112. Lower shaft sleeve; 113. Mounting plate; 114. Plastic package body; 12. Wound stator; 121. Iron core; 122. Coil; 13. Shaft core; 131. Exposed end of shaft core;

[0028] 2. Rotor plastic-encapsulated assembly; 21. Fan rotor; 211. Mounting cavity; 212. Inner wall; 213. Upper bearing chamber; 214. Lower bearing chamber; 215. Plastic-encapsulated rotor; 216. Plastic-encapsulated wind wheel; 217. Plastic-encapsulated bridge section; 218. Air inlet cavity; 22. Magnetic ring;

[0029] 31. Upper bearing; 32. Lower bearing;

[0030] 4. Volute; 411. Upper sleeve;

[0031] 5. Elastic parts. DETAILED DESCRIPTION

[0032] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative efforts shall fall within the scope of protection of the present invention.

[0033] In the description of this application, it should be understood that the terms "inside", "outside", "upper", "middle", "lower", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing this 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 understood as a limitation on this application.

[0034] In the description of this application, it should be noted that, unless otherwise specified or limited, the term "connection" should be understood in a broad sense. For example, it can mean a fixed connection, a detachable connection, or an integral connection; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean internal communication between two components. For those skilled in the art, the specific meanings of the above terms in this application can be understood by those skilled in the art in specific circumstances.

[0035] See Figures 1 to 5 , Figure 1 shows a cross-sectional view of the outer rotor blower provided by the present application; Figure 2 A cross-sectional view of a stator plastic package assembly in an external rotor blower provided by the present application is shown; Figure 3 A cross-sectional view of a rotor plastic package assembly in an external rotor blower provided by the present application is shown; Figure 4 A cross-sectional view of a volute in an external rotor blower provided by the present application is shown; Figure 5 A top view of the volute in the external rotor blower provided in the present application is shown.

[0036] The present application provides an external rotor fan, such as Figures 1 to 3 As shown, it includes a stator plastic packaging component 1 and a rotor plastic packaging component 2. The stator plastic packaging component 1 includes an integrally injected plastic packaging body 11, a wound stator 12 and an axis core 13. The wound stator 12 and the axis core 13 are arranged on the plastic packaging body 11, and the wound stator 12 is evenly arranged around the axis core 13 along the circumferential direction; the rotor plastic packaging component 2 includes an integrally injected fan rotor 21 and a magnetic ring 22. The fan rotor 21 is provided with a bearing, the bearing is sleeved on the axis core 13, and the magnetic ring 22 is arranged around the periphery of the wound stator 12.

[0037] With such a configuration, the stator plastic package assembly 1 is formed by integrally injection molding the plastic package body 11, the winding stator 12, and the shaft core 13, and the rotor plastic package assembly 2 is formed by integrally injection molding the fan rotor 21 and the magnetic ring 22, thereby reducing the difficulty of assembly and improving the efficiency of assembly. At the same time, because the fan rotor 21 and the magnetic ring 22 are integrally injection molded to form the rotor plastic package assembly 2, the fan wheel and the outer rotor are an integrated component, and there is no need for a separate design as in the existing solution. This avoids the phenomenon of dynamic imbalance superposition after the fan wheel and the outer rotor are installed in the existing solution, reduces the dynamic imbalance, and thus reduces the noise generated during the operation of the fan. By adopting an integrated injection molding design, the cumulative fitting tolerance can be reduced. In the design process of the external rotor fan, the precision requirements of each component can be reduced, which facilitates improving the product qualification rate.

[0038] It can be explained that, if Figure 2 As shown, the plastic-encapsulated rotor 215 is provided with an installation cavity 211, which is a circular concave cavity, and the plastic-encapsulated body 114 is a circular protrusion. During installation, the plastic-encapsulated body 114 can be placed in the installation cavity 211, which can reduce the thickness of the stator plastic-encapsulated component 1 and the rotor plastic-encapsulated component 2 after assembly.

[0039] like Figure 1 and Figure 2 As shown, the wound stator 12 includes an iron core 121 and a coil 122 wound around the iron core 121 .

[0040] like Figure 1 and Figure 2 As shown, the bearing includes an upper bearing 31 and a lower bearing 32 , both of which are sleeved on the shaft core 13 , and the plastic-encapsulated rotor 215 is rotatably connected to the outer periphery of the shaft core 13 through the upper bearing 31 and the lower bearing 32 .

[0041] like Figure 2 and Figure 3As shown, the interior of the plastic package body 11 is provided with an inner cavity 111 with an open end, and the shaft core 13 includes an exposed shaft core end 131 located in the inner cavity 111 and extending outward along the opening of the inner cavity 111 at one end; the fan rotor 21 is provided with an inner circumferential wall 212 with one end extending into the inner cavity 111, and the upper bearing 31 and the lower bearing 32 are both arranged on the inner circumferential wall 212.

[0042] In one embodiment, an upper bearing chamber 213 and a lower bearing chamber 214 are formed inside the inner circumferential wall 212 and are arranged around the exposed end 131 of the shaft core. The upper bearing chamber 213 and the lower bearing chamber 214 are arranged at intervals along the axial direction of the exposed end 131 of the shaft core. The upper bearing 31 is arranged in the upper bearing chamber 213, and the lower bearing 32 is arranged in the lower bearing chamber 214.

[0043] In this way, by providing the injection-molded plastic-encapsulated rotor 215 with an upper bearing chamber 213 and a lower bearing chamber 214 arranged around the exposed end 131 of the shaft core, the concentricity of the two bearing chambers is improved. When the two bearings are placed in the two bearing chambers for operation, the high concentricity of the two bearings can reduce the vibration and friction of the two bearings during operation, thereby reducing the noise during the operation of the fan.

[0044] It can be noted that there is no specific limitation on the selection of the upper bearing 31 and the lower bearing 32 .

[0045] As one embodiment, both the upper bearing 31 and the lower bearing 32 use ball bearings, and the ball bearings include a ball bearing outer ring and a ball bearing inner ring; the ball bearing outer ring is embedded and fixed on the inner wall of the upper bearing chamber 213 or the lower bearing chamber 214, and the ball bearing inner ring is sleeved on the outer periphery of the exposed end 131 of the shaft core.

[0046] In this configuration, the bearing is configured as a ball bearing, the inner ring of the ball bearing is sleeved on the outer periphery of the exposed end 131 of the shaft core, and the outer ring of the ball bearing is fixed to the inner wall of the upper bearing chamber 213 or the lower bearing 32 .

[0047] like Figure 1 、 Figure 4 and Figure 5 As shown, the external rotor fan also includes a volute 4, which has a ventilation duct and a mounting port, and the mounting port is connected to the ventilation duct; the plastic package body 11 includes a mounting plate 113 and a plastic package body 114, the mounting plate 113 is detachably mounted on the mounting port, the wound stator 12 is arranged on the plastic package body 114, and the plastic package body 114 and the rotor plastic package assembly 2 are located in the ventilation duct.

[0048] In this arrangement, by using the mounting plate 113 to be disassembled and installed at the mounting port of the volute 4, the wound stator 12, the plastic-sealed body 114 and the rotor plastic-sealed assembly 2 are arranged in the ventilation duct, and there is no need to set up a separate motor installation space outside the volute 4, thereby reducing the axial size of the outer rotor motor on the shaft core 13, and thus reducing the overall volume of the outer rotor fan.

[0049] It can be explained that an upper sleeve 411 is provided on the volute 4 , and the upper sleeve 411 is sleeved on the outer periphery of the exposed end 131 of the shaft core. An elastic member 5 is provided between the upper sleeve 411 and the inner ring of the upper bearing 31 .

[0050] In this arrangement, an upper sleeve 411 is added to the volute 4 to be sleeved on the outer periphery of the exposed end 131 of the shaft core. At this time, since the shaft core 13 is inserted into the inner cavity 111, the shaft core 13 can be supported at two points, making the shaft core 13 more reliable after installation; and the elastic member 5 is arranged between the upper sleeve 411 and the inner ring of the ball bearing of the upper bearing 31, so that the elastic member 5 has the ability to provide pre-pressure for the two bearings, pressing the two bearings to avoid the two bearings from axially moving along the shaft core 13, thereby avoiding the two bearings from driving the fan rotor 21 to vibrate, thereby reducing the noise generated during the operation of the external rotor fan. It is understandable that in the prior art, the upper bearing 31 and the lower bearing 32 are generally fixed to the shaft core 13 by means of an interference fit. If they are installed by means of an interference fit, there is friction between the bearings and the shaft core 13. The lower bearing 32 is relatively low on the shaft core 13, and during installation, it is necessary to overcome a large friction force to install the lower bearing 32 on the lower part of the shaft core 13. Similarly, it is also necessary to overcome friction force when installing the upper bearing 31, resulting in greater difficulty in installation. By providing the elastic member 5, the upper bearing 31 and the lower bearing 32 of the present application only need to be sleeved on the shaft core 13, without having to overcome a large friction force, and then the upper bearing 31 is positioned using the elastic member 5, which facilitates assembly.

[0051] It is understandable that in the prior art, the shaft core 13 is provided on the rotor, and the bearing 13 is provided on the stator. For overall stability, a metal bearing sleeve is also provided on the stator. The present application adopts a design that overturns the shaft system in the prior art. By plastic-sealing the shaft core 13 as a whole on the plastic-sealed body 11 and providing the bearing 13 on the fan rotor 21, assembly is facilitated. The elastic member 5 is used to position the upper bearing 31, which also facilitates subsequent maintenance.

[0052] It should be noted that there is no specific limitation on the type of the elastic member 5 .

[0053] In one embodiment, the elastic member 5 is a spring. During installation, the spring is compressed to press the spring against the inner race of the ball bearing in the upper bearing chamber 213. This facilitates alignment of the inner race with the outer race, reduces friction during bearing rotation, ensures smooth rotation, and further reduces noise generated during operation of the outer rotor fan.

[0054] Likewise, the inner cavity 111 is provided with a lower sleeve 112 for contacting the bearing inner ring of the lower bearing 32. This arrangement facilitates positioning of the ball bearing inner ring in the lower bearing chamber 214.

[0055] like Figure 1 、 Figures 3 to 5 As shown, the volute 4 is provided with an air inlet connected to the ventilation duct, and the fan rotor 21 includes a plastic-sealed rotor 215, a plastic-sealed wind wheel 216, and a plastic-sealed bridging section 217 integrally connected between the plastic-sealed rotor 215 and the plastic-sealed wind wheel 216. The plastic-sealed rotor 215, the plastic-sealed bridging section 217 and the plastic-sealed wind wheel 216 enclose an air inlet cavity 218 that is recessed toward the air inlet, thereby reducing the resistance of air entering the air inlet cavity 218; the magnetic ring 22 is provided on the plastic-sealed rotor 215.

[0056] It can be explained that the plastic-sealed wind wheel 216 includes multiple blades arranged at intervals along the circumferential direction, and an air flow channel is formed between two adjacent blades. The multiple air flow channels are connected. When the fan rotor 21 rotates, the plastic-sealed wind wheel 216 is used to guide the air flowing into the internal ventilation duct of the volute 4 at the air inlet of the volute 4 to the air outlet of the volute.

[0057] It should be noted that, in the above embodiment, the material selected for the plastic package 11 is BMC. Specifically, the wound stator 12 and the shaft core 13 obtained by assembling the iron core 121 and the coil 122 are placed in an injection mold, and injection molding is performed using the thermosetting material BMC, and the BMC material forms the plastic package 11. This arrangement can isolate the air during the heat dissipation of the iron core 121 and the coil 122, thereby preventing the iron core 121 and the coil 122 from aging and corrosion; in addition, the stator plastic package assembly 1 is placed on the flow path of the air in the air flow channel, thereby improving the heat dissipation effect, improving the reliability of the outer rotor blower, and increasing the life of the outer rotor blower.

[0058] In one embodiment, the magnetic ring 22 includes at least one set of north-pole magnets and south-pole magnets, which are staggered circumferentially. Specifically, at least one north-pole and at least one south-pole are plastic-encapsulated to form the magnetic ring 22 with a plastic protective layer. The magnetic ring 22 is then placed in an injection mold and injection-molded to form the fan rotor 21.

[0059] During installation, take out the stator plastic packaging component 1 and the rotor plastic packaging component 2 obtained by injection molding, and press the two ball bearings into the upper bearing chamber 213 and the lower bearing chamber 214 respectively; then put the inner rings of the two ball bearings on the exposed end 131 of the shaft core; then put the spring on the inner ring of the ball bearing in the upper bearing chamber 213; then put the upper shaft sleeve 411 into the exposed end 131 of the shaft core; finally, complete the fixation of the volute 4 and the plastic packaging body 11. If the volute 4 and the plastic packaging body 11 are both provided with a snap-fit ​​structure, the snap-fit ​​can be completed during installation, or a threaded structure can be used to complete the connection and fixation of the volute 4 and the plastic packaging body 11. If the outer edge of the volute 4 and the plastic packaging body 11 is provided with a connecting hole, such as a threaded connecting hole, bolts can be used to complete the fastening during installation.

[0060] In the specific contents of the above-mentioned specific implementation methods, the various technical features can be combined in any non-contradictory manner. In order to make the description concise, not all possible combinations of the above-mentioned technical features are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0061] The specific contents of the above-mentioned specific embodiments merely represent several embodiments of the present invention. While the description is relatively specific and detailed, it should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art may make various modifications and improvements without departing from the scope of the present invention, and these modifications and improvements fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be based on the appended claims.

Claims

1. An external rotor fan, characterized in that: The invention comprises a stator plastic packaging component (1) and a rotor plastic packaging component (2), wherein the stator plastic packaging component (1) comprises an integrally-injected plastic packaging body (11), a winding stator (12) and an axis core (13), wherein the winding stator (12) and the axis core (13) are arranged on the plastic packaging body (11), and the winding stator (12) is uniformly arranged around the axis core (13) along the circumferential direction; and the rotor plastic packaging component (2) comprises an integrally-injected fan rotor (21) and a magnetic ring (22), wherein the fan rotor (21) is rotatably connected to the axis core (13), and the magnetic ring (22) is arranged around the periphery of the winding stator (12).

2. The outer rotor fan according to claim 1, characterized in that: The fan rotor (21) is provided with a bearing, and the bearing comprises an upper bearing (31) and a lower bearing (32), and the upper bearing (31) and the lower bearing (32) are both sleeved on the shaft core (13).

3. The outer rotor fan according to claim 2, characterized in that: The plastic-sealed body (11) is provided with an inner cavity (111) with one end being open, and the shaft core (13) includes an exposed shaft core end (131) located in the inner cavity (111) and extending outward along the opening of the inner cavity (111); the fan rotor (21) is provided with an inner peripheral wall (212) with one end extending into the inner cavity (111), and the upper bearing (31) and the lower bearing (32) are both arranged on the inner peripheral wall (212).

4. The outer rotor fan according to claim 3, characterized in that: An upper bearing chamber (213) and a lower bearing chamber (214) are formed inside the inner peripheral wall (212) and are arranged around the exposed end (131) of the shaft core. The upper bearing chamber (213) and the lower bearing chamber (214) are arranged at intervals along the axial direction of the exposed end (131) of the shaft core. The upper bearing (31) is arranged in the upper bearing chamber (213), and the lower bearing (32) is arranged in the lower bearing chamber (214).

5. The outer rotor fan according to claim 4, characterized in that: The inner cavity (111) is provided with a lower sleeve (112) for abutting against the bearing inner ring of the lower bearing (32).

6. The outer rotor fan according to claim 2, characterized in that: The upper bearing (31) and the lower bearing (32) are both ball bearings.

7. The outer rotor fan according to claim 3, characterized in that: The invention also includes a volute (4), the volute (4) having a ventilation duct and a mounting port, the mounting port being in communication with the ventilation duct; the plastic-sealed body (11) includes a mounting plate (113) and a plastic-sealed main body (114), the mounting plate (113) being detachably mounted on the mounting port, the winding stator (12) being arranged on the plastic-sealed main body (114), and the plastic-sealed main body (114) and the rotor plastic-sealed assembly (2) being located in the ventilation duct.

8. The outer rotor fan according to claim 7, characterized in that: An upper sleeve (411) is provided on the volute (4), and the upper sleeve (411) is sleeved on the outer periphery of the exposed end (131) of the shaft core. An elastic member (5) is provided between the upper sleeve (411) and the inner ring of the upper bearing (31).

9. The outer rotor fan according to claim 7, characterized in that: The volute (4) is provided with an air inlet communicated with a ventilation duct; the fan rotor (21) comprises a plastic-sealed rotor (215), a plastic-sealed wind wheel (216), and a plastic-sealed bridge section (217) integrally connected between the plastic-sealed rotor (215) and the plastic-sealed wind wheel (216); the plastic-sealed rotor (215), the plastic-sealed bridge section (217), and the plastic-sealed wind wheel (216) enclose an air inlet cavity (218) that is recessed in a direction away from the air inlet; and the magnetic ring (22) is provided on the plastic-sealed rotor (215).

10. The outer rotor blower according to any one of claims 1 to 9, characterized in that: The magnetic ring (22) comprises at least one group of N-pole magnetic steel and S-pole magnetic steel, and the N-pole magnetic steel and the S-pole magnetic steel are staggered along the circumferential direction.

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