Fans and electrical equipment

Abstract

The present invention provides a fan and electrical equipment, the fan comprises: a driving structure; an impeller, the impeller comprises a cover plate, the cover plate is mounted on the driving structure, the cover plate is recessed in the axial direction of the impeller, and the diameter of the cover plate gradually increases along the air inlet direction; a hood, the hood is arranged on the impeller, and the hood is provided with an air inlet and an air outlet connected with the air inlet; a diffuser, located at one end of the impeller facing the air outlet, comprising a first convex portion connected to the driving structure, the first convex portion protrudes in the direction of the hood, and the diameter of the end of the first convex portion close to the cover plate is smaller than the diameter of the end away from the cover plate, and also comprising an inner ring arm and an outer ring arm, the outer ring arm is smoothly transitionally connected with the hood; the hood, the cover plate, and the diffuser define an air duct, the air duct comprises a variable cross-section portion and a uniform cross-section portion, the variable cross-section portion is arranged close to the air inlet, and the uniform cross-section portion is arranged close to the air outlet. The fan provided by the present invention has very smooth airflow in the entire air duct, which improves the efficiency of the fan.

Description

Technical Field

[0001] The present invention relates to the technical field of household appliances, and in particular to a fan and electrical equipment. Background Art

[0002] At present, high-speed fans generally use electric motors to drive the impeller to rotate at high speed to form a negative pressure environment in the sealed housing, so that dust and other debris are sucked into the dust collection device, thereby achieving a good air supply effect. The development trend of high-speed, high-efficiency and high-power fans is obvious, but high power and high speed will aggravate fluid and mechanical losses, resulting in excessive temperature rise, which brings great challenges to efficient air duct design, bearing design and whole machine heat dissipation design. Small high-speed fans in the existing technology can achieve an efficiency of 52.5% under the working conditions of 400W~120000rpm, and the efficiency does not exceed 50% under the working conditions of 500W~125000rpm, and complex flow path design is required to solve the heat dissipation problem of heating components. When consumer demand changes, such as demanding greater suction (increased power) or low-power and lightweight products, the power range and speed range that the existing technology can efficiently cover are very narrow, and the overall machine efficiency is highly sensitive to design input. Summary of the invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art or related art.

[0004] To this end, a first aspect of the present invention provides a fan.

[0005] The second aspect of the present invention also provides an electrical device.

[0006] In view of this, the first aspect of the present invention proposes a fan, comprising: a driving structure; an impeller, the impeller comprising a cover plate, the cover plate being mounted on the driving structure, the cover plate being recessed in the axial direction of the impeller, and the diameter of the cover plate gradually increases along the air inlet direction; a hood, the hood being arranged on the impeller, the hood being provided with an air inlet and an air outlet connected to the air inlet; a diffuser, the diffuser being located at one end of the impeller facing the air outlet, the diffuser comprising a first convex portion connected to the driving structure, the first convex portion protruding in the direction of the hood, and the diameter of the end of the first convex portion close to the cover plate being smaller than the diameter of the end away from the cover plate, the diffuser further comprising an inner ring arm connected to the first convex portion and an outer ring arm sleeved on the outside of the inner ring arm, the outer ring arm being smoothly transitionally connected to the hood, the first convex portion, the inner ring arm, and the outer ring arm being coaxially arranged; wherein the hood, the cover plate, and the diffuser define an air duct, the air duct comprising a variable cross-section portion and a constant cross-section portion, the variable cross-section portion being arranged close to the air inlet, and the constant cross-section portion being arranged close to the air outlet.

[0007] The fan provided by the present invention comprises a driving structure, a wind shield, an impeller and a diffuser. The driving structure drives the impeller to rotate so that the airflow flows from the air inlet to the air outlet. The diffuser comprises a first convex portion, an inner ring arm and an outer ring arm which are coaxially arranged. The first convex portion is arranged close to the impeller. The inner ring arm is connected to the first convex portion and is located below the first convex portion. The outer ring arm and the inner ring arm are sleeved together. The first convex portion protrudes toward the wind shield, and the diameter of the first convex portion gradually increases. The wind shield, the cover plate and the diffuser define an air duct. The airflow flows from the air inlet to the air outlet through the air duct. The space formed between the impeller and the wind shield changes the direction and kinetic energy of the fluid. When the fluid passes between the first convex portion and the wind shield, the airflow flows from the air inlet to the air outlet through the air duct. The space formed between the impeller and the wind shield changes the direction and kinetic energy of the fluid. When the air duct is formed, the dynamic pressure is converted into static pressure, and the airflow is guided radially outward and downward. Finally, the airflow is led out of the air duct through the annular wind cavity composed of the inner ring arm and the outer ring arm. The airflow in the entire air duct flows very smoothly, reducing the impact loss and separation loss. The wall surface of the wind hood and the wall surface of the diffuser are connected by a smooth transition, that is, the diameter of the connected part between the wall surface of the wind hood and the wall surface of the diffuser is the same. Furthermore, the inner wall surface of the wind hood and the inner wall surface of the diffuser are connected by a smooth transition, so that the airflow will not generate impact when passing through the connection between the wind hood and the diffuser, thereby reducing the impact loss at the connection and improving the efficiency of the fan.

[0008] Furthermore, the air duct includes a variable cross-section portion and a constant cross-section portion, the variable cross-section portion is close to the air inlet, and the constant cross-section portion is close to the air outlet, and along the air inlet direction, the cross-sectional area of ​​the variable cross-section portion gradually decreases, while the cross-sectional area of ​​the constant cross-section portion remains unchanged, and the variable cross-section portion and the constant cross-section portion are smoothly transitioned and connected, so that the airflow flows very smoothly in the air duct, reducing impact loss and separation loss.

[0009] Furthermore, the space between the impeller and the wind cover constitutes a variable cross-section portion, and the space between the diffuser and the wind cover constitutes a constant cross-section portion.

[0010] Furthermore, the airflow enters the air duct from the air inlet approximately along the axial direction of the driving structure, and the distance between the center line of the air duct and the axis of the driving structure gradually increases, so that the airflow is gradually guided radially outward and downward of the driving structure when passing through the air duct.

[0011] Furthermore, the wind shield, the impeller and the diffuser are all coaxially arranged, and the wall surface of the first convex portion facing the wind shield is a smooth convex surface with a gradually increasing diameter.

[0012] The above-mentioned fan provided by the present invention may also have the following additional technical features:

[0013] In any of the above technical solutions, preferably, the driving structure includes: a stator assembly, which is arranged relative to the air outlet so that the wind flow out of the air outlet blows directly toward the stator assembly.

[0014] In this technical solution, the driving structure includes a stator assembly, and the stator assembly is arranged at the air outlet, so that the wind flowing out of the air outlet blows directly toward the stator assembly, thereby improving the heat dissipation effect of the stator assembly.

[0015] In any of the above technical solutions, preferably, an angle between an extension direction of one end of the cover plate toward the first protrusion and an extension direction of one end of the first protrusion toward the impeller is less than or equal to a first threshold.

[0016] In this technical solution, the angle between the extension direction of one end of the cover plate toward the first protrusion and the extension direction of one end of the first protrusion toward the cover plate is less than or equal to a first threshold value, that is, at the two adjacent ends of the cover plate and the first protrusion, the angle between the tangent passing through the end circumference of the first protrusion and the tangent passing through the end circumference of the cover plate is less than or equal to the first threshold value, so that the angle between the flow direction of the airflow when passing through the end of the cover plate toward the first protrusion and the flow direction of the airflow when passing through the first protrusion toward the end of the cover plate is less than or equal to the first threshold value, and the value of the first threshold value can be between -2° and 2°. Of course, the first threshold value can also be other smaller angles, that is, the end of the first protrusion is roughly arranged in the tangent direction of the end of the cover plate, so that the transition between the first protrusion and the end of the cover plate is smoother, and the impact loss is greatly reduced when the airflow passes through the connection between the first protrusion and the cover plate, thereby improving the efficiency of the fan.

[0017] Furthermore, the diameter of the end of the first protrusion facing the air inlet is greater than or equal to the diameter of the end of the impeller facing the air outlet, that is, of the two ends close to the first protrusion and the impeller, the end of the first protrusion is larger than the end of the impeller, so that the airflow is gradually guided radially outward and downward of the driving structure when flowing from the impeller to the first protrusion.

[0018] In any of the above technical solutions, preferably, an annular recessed portion is provided at one end of the first convex portion facing the air inlet, and an annular raised portion is provided at one end of the cover plate facing the diffuser, and the recessed portion and the raised portion are clearance-matched.

[0019] In this technical solution, a recessed portion is provided on the first convex portion, and a raised portion is provided on the cover plate, and the recessed portion and the raised portion are matched with each other. Since the cover plate rotates at high speed and the diffuser is fixedly arranged, the two must be clearance-matched. Furthermore, the gap between the recessed portion and the raised portion is smaller than a predetermined threshold value, that is, the recessed portion and the raised portion are clearance-matched with each other. When the fluid flows from the cover plate to the first convex surface, it is inevitable that the fluid will enter the gap between the two and cause leakage loss. The small clearance fit can reduce such leakage, thereby improving efficiency. At the same time, the raised portion is located below the cover plate and can be used as a balance ring of the cover plate for balancing and weight removal, and there is no need to separately set a balance ring of the cover plate, thereby reducing the number of parts, simplifying the assembly process, and reducing costs.

[0020] In any of the above technical solutions, preferably, the diameter of the connection between the first protrusion and the inner ring arm is the same as the diameter of the outer wall surface of the inner ring arm and the connection is smoothly transitioned.

[0021] In this technical solution, the diameter of the connection between the first protrusion and the inner ring arm is the same as the diameter between the outer wall surfaces of the inner ring arm. Furthermore, the connection between the first protrusion and the inner ring arm is a smooth transition connection, thereby reducing the impact loss of the airflow when passing through the connection between the first protrusion and the inner ring arm, thereby improving the working efficiency of the fan.

[0022] In any of the above technical solutions, preferably, a first notch is provided on the side of the outer ring arm facing away from the axis of the driving structure, and a second notch matching the first notch is provided on the side of the wind cover facing the axis of the driving structure, the first notch and the second notch are both annular, and the side of the outer ring arm facing the air inlet is against the bottom of the second notch.

[0023] In this technical solution, a first notch is provided on the outer side of the outer ring arm, and a second notch is provided on the inner side of the corresponding position of the wind hood, and the first notch cooperates with the second notch. Furthermore, the depth of the second notch along the radial direction of the first protrusion is equal to the remaining thickness of the outer ring arm after the first notch is provided, so that a smooth transition connection is achieved between the connected wind hood and the outer ring arm. At the same time, through the cooperation of the first notch and the second notch, radial positioning of the wind hood and the diffuser is achieved, and the coaxiality of the diffuser and the wind hood is ensured.

[0024] Furthermore, the first notch and the second notch are both annular, and the side of the outer ring arm facing the air inlet abuts against the bottom of the second notch.

[0025] In this technical solution, both the first notch and the second notch are annular, thereby improving the reliability of the connection between the diffuser and the wind hood. The side of the outer ring arm facing the air inlet abuts against the bottom of the second notch, that is, the top of the outer ring arm abuts against the bottom of the groove of the second notch, thereby realizing the axial positioning of the diffuser and the wind hood, and at the same time ensuring a smooth transition connection between the inner wall surface of the wind hood and the inner wall surface of the outer ring arm, thereby ensuring the smoothness of the medium flow.

[0026] In any of the above technical solutions, preferably, the diffuser also includes: a first blade, which is arranged between the inner ring arm and the outer ring arm, and the two ends of the first blade along the radial direction of the diffuser are respectively attached to the inner ring arm and the outer ring arm, so that the first blade and the inner ring arm and the outer ring arm constitute an air guide cavity; wherein the first blade is spiral-shaped, and the first blade includes an inlet end and an outlet end along the air inlet direction, and the inlet end is located behind the outlet end along the rotation direction of the impeller.

[0027] In the technical solution, the diffuser also includes a first blade, which is arranged between the inner ring arm and the outer ring arm, wherein the two ends of the first blade along the radial direction of the diffuser are respectively attached to the inner ring arm and the outer ring arm, that is, the first blade extends to the inner ring arm in the direction of the diffuser axis, and extends to the outer ring arm in the direction away from the diffuser axis, so that the root of the first blade is attached to the inner ring arm, and the top is attached to the outer ring arm, so that an air guide cavity is formed between the inner ring arm, the first blade, and the outer ring arm, and the air guide cavity formed by the annular space between the inner ring arm and the outer ring arm and the first blade is relatively closed. After the airflow enters the air guide cavity, it only flows out from the outlet of the air guide cavity, avoiding the efficiency loss caused by the sealing leakage of the first blade during the diffusion process, and also simplifying the assembly process. Among them, the first blade is spiral, and along the rotation direction of the impeller, the inlet end is located after the outlet end, which is conducive to reducing the along-the-way loss of the airflow and the impact loss at the outlet end.

[0028] In any of the above technical solutions, preferably, the first blade is completely located in the wind cavity between the inner ring arm and the outer ring arm.

[0029] In this technical solution, the first blade is completely located in the air guide cavity in the axial direction, that is, the first blade is completely located in the annular wind cavity formed by the inner ring arm and the outer ring arm, which can ensure the uniformity of the airflow at the inlet and outlet ends of the first blade and avoid the influence of other structures on the airflow.

[0030] In any of the above technical solutions, preferably, the angle between the extension direction of the inlet end and the radial direction of the inner ring arm is less than or equal to a second threshold; the outlet end includes a first inner end point connected to the inner ring arm and a first outer end point connected to the outer ring arm, and along the rotation direction of the impeller, the first inner end point is located in front of the first outer end point.

[0031] In this technical solution, the extension direction of the inlet end, i.e., the extension direction of the inlet end from the inner ring arm to the outer ring arm, and the angle between the extension direction of the inlet end and the radial direction of the inner ring arm are less than or equal to a second threshold value, and the value range of the second threshold value may be determined according to the specific situation, such as -2° to 2° or other suitable values, that is, the inlet end is roughly arranged in the radial extension line direction of the inner ring arm; the first inner end point of the outlet end is located in front of the first outer end point, that is, the first inner end point is located in front of the first outer end point.

[0032] In any of the above technical solutions, preferably, along the axial direction of the diffuser, the inlet end is a smooth curved surface convex toward the impeller, and the outlet end is a smooth curved surface convex away from the impeller; along the rotation direction of the impeller, of the two side surfaces of the first blade, the side surface located in front convexes in the rotation direction of the impeller, and the side surface located in the rear is concave in the rotation direction of the impeller.

[0033] In this technical solution, along the axial direction of the diffuser, the inlet end is a smooth curved surface convex toward the impeller, and the outlet end is a smooth curved surface convex away from the impeller, thereby ensuring the uniformity of the airflow at the inlet end and reducing the impact loss at the outlet end. Along the rotation direction of the impeller, of the two side surfaces of the first blade, the side surface located in the front, that is, the pressure surface of the first blade, is convex toward the rotation direction of the impeller, and the side surface located in the rear, that is, the back pressure surface of the first blade, is concave toward the rotation direction of the impeller, which is beneficial to reducing the along-the-way loss of the airflow and further beneficial to improving the efficiency of the fan.

[0034] In any of the above technical solutions, preferably, the inner ring arm, the first blade and the outer ring arm are an integrated structure.

[0035] In this technical solution, the inner ring arm and the outer ring arm are in a circular ring shape, wherein the outer ring arm is arranged radially outside the inner ring arm, and the spiral first blade is arranged between the inner ring arm and the outer ring arm, and is connected with the inner ring arm and the outer ring arm to form an integrated part. Since the two ends of the first blade along the radial direction of the inner ring arm are respectively attached to the inner ring arm and the outer ring arm, the first blade and the inner ring arm and the outer ring arm can be easily molded as an integrated part, without the need to make the first blade and one of the inner ring arm and the outer ring arm integrally molded and then assembled and connected with the other. The setting of the integrated diffuser can form a sealed air guide cavity between the cylinders relatively arranged between the inner ring arm and the outer ring arm and the pressure surface and back pressure surface relatively arranged between the two adjacent first blades, thereby avoiding the efficiency loss caused by the leakage of the first blade during the diffusion process, and also simplifying the assembly process.

[0036] In any of the above technical solutions, preferably, there are multiple first blades, and the multiple first blades are evenly distributed between the inner ring arm and the outer ring arm along the circumference of the inner ring arm.

[0037] In this technical solution, there are multiple first blades, and the multiple first blades are evenly distributed between the inner ring arm and the outer ring arm along the circumference of the inner ring arm. Furthermore, there are twelve first blades.

[0038] In any of the above technical solutions, preferably, the impeller also includes: a second blade, which is arranged on the cover plate, and the second blade is located in the air duct; wherein, along the air inlet direction, the second blade includes a leading edge close to the air inlet and a trailing edge close to the air outlet, and along the rotation direction of the impeller, the leading edge is located in front of the trailing edge.

[0039] In this technical solution, the impeller also includes a second blade, and the outer wall surface of the cover plate is a smooth concave surface, wherein the airflow enters the air duct from the air inlet, obtains a relatively uniform flow field, and then enters the independent flow channel space formed by two adjacent second blades through the leading edge, thereby avoiding the influence of the flow field change at the inlet end on the fluid movement between the second blades. The leading edge is located in front of the trailing edge, so that the extension direction of the flow channel space between the two adjacent second blades is the same as the rotation direction of the impeller.

[0040] Furthermore, the second blade intersects with the outer wall surface of the cover plate to form a blade root, and the second blade extends in a direction away from the outer wall surface of the cover plate and forms a blade top at a location where the outer diameter is the largest.

[0041] In any of the above technical solutions, preferably, the diameter of the cover plate gradually increases along the air inlet direction.

[0042] In this technical solution, the diameter of the cover plate gradually increases along the air inlet direction. Furthermore, the outer wall surface of the cover plate is a smooth concave surface with a gradually increasing diameter.

[0043] In any of the above technical solutions, preferably, the angle between the extension direction of the leading edge and the axial direction of the driving structure is within the range of 76°±2°; and the trailing edge is located on the cylindrical surface formed by the outer side wall of the raised portion.

[0044] In this technical solution, the angle between the imaginary straight line where the leading edge is located and the axis of the cover plate is in the range of 76°±2°, so that the leading edge is roughly arranged along the radial direction of the cover plate. Specifically, the angle between the imaginary straight line where the leading edge is located and the axis of the cover plate is greater than or equal to 74° and less than or equal to 78°; the trailing edge is located on the cylindrical surface formed by the outer side wall of the raised portion, thereby reducing the impact loss of the airflow when passing through the trailing edge.

[0045] In any of the above technical solutions, preferably, the leading edge includes a second inner endpoint connected to the cover plate and a second outer endpoint away from the cover plate, along the rotation direction of the impeller, the second outer endpoint is located in front of the second inner endpoint, from the air outlet to the air inlet, the second inner endpoint is located below the second outer endpoint, and the second outer endpoint is located at the end of the cover plate facing the air inlet and below the air inlet; the trailing edge includes a third inner endpoint connected to the cover plate and a third outer endpoint away from the cover plate, the third inner endpoint is located on the circumference of one end of the impeller facing the diffuser, and from the air outlet to the air inlet, the third outer endpoint is located above the third inner endpoint.

[0046] In this technical solution, since the leading edge starts from the root of the leading edge and extends radially outward and upward of the cover plate, the airflow flows into the flow channel formed by the second blade in an inclined direction, which effectively controls the wind volume and wind pressure of the leading edge and reduces the loss of the leading edge fluid. At the same time, the second outer endpoint is arranged above the second inner endpoint, which can ensure that the streamline length of the top of the second blade is slightly larger than the streamline length of the root of the second blade, so that the airflow has a relatively uniform flow state at the trailing edge. Specifically, the second inner endpoint and the second outer endpoint are two endpoints at the intersection of the pressure surface or back pressure surface of the second blade and the cover plate; the second outer endpoint is located at the end of the cover plate facing the air inlet and below the air inlet, avoiding leakage loss of airflow entering the air duct; the connection between the trailing edge and the cover plate is located on the circumference of one end of the impeller facing the diffuser, so that the airflow can flow smoothly out of the flow channel formed by the second blade, and the third outer endpoint is located above the third inner endpoint. Reasonable setting of the inclination angle of the trailing edge is conducive to reducing fluid loss at the outlet end.

[0047] Specifically, the extending direction of the leading edge is the direction of the line between the second inner endpoint and the second outer endpoint, and the extending direction of the trailing edge is the extending direction from the root of the trailing edge to the top of the trailing edge.

[0048] In any of the above technical solutions, preferably, in the projection of the impeller on a plane perpendicular to the axis of the drive structure, the angle between the line connecting the second inner end point and the axis center of the drive structure and the line connecting the second outer end point and the axis center of the drive structure is greater than or equal to 0° and less than or equal to 5°.

[0049] In this technical solution, the angle between the line connecting the second inner end point and the axis and the line connecting the second outer end point and the axis is greater than or equal to 0° and less than or equal to 5°. The small lead angle at the top of the leading edge is conducive to fitting the fluid drainage while ensuring the manufacturability of the impeller.

[0050] In any of the above technical solutions, preferably, in the projection of the impeller on a plane perpendicular to the axis of the drive structure, the angle between the line connecting the third inner end point and the axis center of the drive structure and the line connecting the third outer end point and the axis center of the drive structure is greater than or equal to -2° and less than or equal to 2°.

[0051] In this technical solution, the inclination angle of the trailing edge is reasonably set, which is conducive to reducing the fluid loss at the outlet of the impeller, reducing the gap leakage at the outlet of the impeller, reducing the secondary flow at the outlet of the impeller and the existence of the jet wake, and improving the efficiency of the impeller. Preferably, the angle between the line connecting the third inner end point and the axis of the drive structure and the line connecting the third outer end point and the axis of the drive structure is greater than or equal to -2° and less than or equal to 2°, that is, the top of the trailing edge is roughly set in the axial direction of the root of the trailing edge.

[0052] In any of the above technical solutions, preferably, the leading edge protrudes toward the air inlet, and the length of the trailing edge is smaller than the length of the leading edge.

[0053] In this technical solution, the leading edge is a smooth curved surface that bulges toward the air inlet, smoothly connecting the pressure surface and the suction surface. The second blade extends forward toward the air inlet and becomes thinner, which can increase the length of the second blade while reducing the relative diffusion speed. The length of the trailing edge is less than the length of the leading edge, which can effectively control the ratio of the inlet and outlet areas of the flow channel between adjacent second blades, reduce the diffusion loss of the flow, broaden the high-efficiency zone under small flow conditions, and reduce aerodynamic noise.

[0054] Further, the thickness of the leading edge is smaller than the thickness of the trailing edge.

[0055] In any of the above technical solutions, preferably, the ratio of the length of the trailing edge to the length of the leading edge is greater than or equal to 0.4 and less than or equal to 0.46.

[0056] In this technical solution, the length of the trailing edge is reasonably set, which is conducive to reducing the fluid loss at the outlet end, reducing the gap leakage at the impeller outlet, reducing the secondary flow and jet wake at the impeller outlet, and improving the impeller efficiency. Preferably, the ratio of the length of the trailing edge to the length of the leading edge is greater than or equal to 0.4 and less than or equal to 0.46.

[0057] In any of the above technical solutions, preferably, there is a first gap between the end of the second blade away from the axis of the impeller and the inner wall surface of the wind cover; wherein the first gap is equidistantly arranged from the air inlet to the air outlet, or the first gap gradually decreases from the air inlet to the air outlet.

[0058] In this technical solution, since the impeller and the wind cover rotate at a relatively high speed, a clearance is required between the two to ensure that the clearance is gradually reduced from top to bottom or is equidistantly arranged from top to bottom, which can effectively improve the efficiency of the fan.

[0059] In any of the above technical solutions, preferably, the first gap is greater than or equal to 0.2 mm and less than or equal to 0.3 mm.

[0060] In this technical solution, if the first gap is too large, it will seriously affect the efficiency of the air duct, and if the first gap is too small, it will greatly increase the difficulty of assembly. The first gap is most appropriately selected between 0.2mm and 0.3mm. At the same time, since the length of the leading edge is greater than the length of the trailing edge, the impact of the first gap on the efficiency at the trailing edge is greater than that at the leading edge. Therefore, ensuring that the first gap is gradually reduced from top to bottom can effectively improve the efficiency of the fan.

[0061] In any of the above technical solutions, preferably, there are multiple second blades, and the multiple second blades are evenly arranged on the cover plate along the circumference of the cover plate.

[0062] In this technical solution, there are multiple second blades, and the multiple second blades are evenly arranged on the cover plate along the circumference of the cover plate.

[0063] Specifically, the projection of the root of the second blade on the plane perpendicular to the axis direction satisfies: the wrap angle θ1 is within the range of 120°±3°; the projection of the top of the second blade on the plane perpendicular to the axis direction satisfies: the wrap angle θ2 is within the range of 123°±3°, the wrap angle θ1 is the angle between the two endpoints of the projection of the root of the second blade on the plane perpendicular to the axis direction and the axis center, and the wrap angle θ2 is the angle between the two endpoints of the projection of the top of the second blade on the plane perpendicular to the axis direction and the axis center.

[0064] Preferably, θ2 ≥ θ1.

[0065] Specifically, the larger the second blade wrap angle, the smaller the flow separation and vortex in the flow channel, the closer the flow is to the second blade profile, and the higher the impeller speed is at the same impeller diameter; but an excessively large second blade wrap angle will cause greater friction loss, the high efficiency point will move toward the direction of small flow, and it will also cause demolding difficulties. The wrap angle range given in the present invention can make the impeller work efficiently within the speed range of 100,000 rpm to 150,000 rpm.

[0066] Preferably, the projection of the root of the second blade on the plane perpendicular to the axis direction satisfies: the inlet placement angle β1 is within the range of 23.5°±3°; the outlet placement angle β2 is within the range of 33.5±3°; the projection of the top of the second blade on the plane perpendicular to the axis direction satisfies: the inlet placement angle β3 is within the range of 0° to 3°; the outlet placement angle β4 is within the range of 28.5±3°.

[0067] Specifically, the choice of the inlet placement angle will affect the quality of the flow state when the fluid enters the impeller flow channel. The appropriate inlet placement angle can reduce the displacement effect of the inlet of the second blade root, increase the flow area, and avoid serious flow separation at the inlet end of the suction surface, reducing the flow loss. The choice of the outlet placement angle will affect the vacuum degree of the fan. Reducing the outlet placement angle while reducing the outer diameter of the impeller is an effective measure to improve the efficiency of the centrifugal fan. Since the operating speed of the impeller of the present technical solution can reach 150,000 rpm, an excessively large impeller diameter will cause insufficient structural strength and the impact of unbalanced mass on the rotor assembly, but a too small outlet placement angle will affect the manufacturability of the product. The selection of the above-mentioned inlet placement angle and outlet placement angle can keep the inlet and outlet fluid states of the impeller uniform within the speed range of 100,000 rpm to 150,000 rpm, reduce fluid losses, improve the vacuum degree and efficiency of the fan, and reduce the outer diameter of the impeller to ensure strength and manufacturability.

[0068] Preferably, the maximum diameter of the impeller does not exceed 32 mm.

[0069] Preferably, the outer wall surface of the cover plate is formed into a smooth concave surface, the upper end inflow angle δ1 of the outer wall surface of the cover plate is within the range of 4°±2°, and the lower end outflow angle δ2 is within the range of 57.5°±2°.

[0070] Preferably, the thickness of the second blade gradually increases from the leading edge to the trailing edge, and the ratio of the leading edge thickness to the trailing edge thickness is not less than 80%.

[0071] Preferably, seven second blades are distributed on the impeller at equal intervals in the circumferential direction.

[0072] In any of the above technical schemes, preferably, the inner wall surface of the wind hood includes a first inner wall surface corresponding to the cover plate and a second inner wall surface corresponding to the first convex portion, the first inner wall surface protrudes from the outer side of the wind hood toward the axial direction of the wind hood, and the second inner wall surface is recessed from the axis of the wind hood toward the outer side of the wind hood; wherein the first inner wall surface, the second inner wall surface, the outer wall surface of the cover plate, the outer wall surface of the first convex portion, the outer wall surface of the inner ring arm, and the inner wall surface of the outer ring arm constitute an air duct.

[0073] In this technical solution, the inner wall surface of the wind hood includes a first inner wall surface and a second inner wall surface, the first inner wall surface is arranged corresponding to the cover plate, and the second inner wall surface is arranged corresponding to the first convex portion, and the first inner wall surface is a smooth convex surface, and the second inner wall surface is a smooth concave surface, so as to form a variable cross-section portion and a constant cross-section portion together with the cover plate and the first convex portion and the inner ring arm and the outer ring arm. Specifically, the first inner wall surface, the second inner wall surface, the outer wall surface of the cover plate, the outer wall surface of the first convex portion, the outer wall surface of the inner ring arm, and the inner wall surface of the outer ring arm constitute an air duct.

[0074] In any of the above technical solutions, preferably, along the air inlet direction, the diameter of the first inner wall surface and the diameter of the second inner wall surface gradually increase.

[0075] In this technical solution, the diameter of the inner wall surface of the wind hood gradually increases along the air inlet direction.

[0076] In any of the above technical solutions, preferably, the diameter of the connection between the second inner wall surface and the outer ring arm is the same as the diameter of the inner wall surface of the outer ring arm; along the axial direction of the driving structure, the height difference between the connection between the second inner wall surface and the outer ring arm, and the connection between the first protrusion and the inner ring arm is less than or equal to a third threshold.

[0077] In this technical solution, the diameter of the connection between the second inner wall surface and the outer ring arm is the same as the diameter of the inner wall surface of the outer ring arm so that the inner wall surface of the wind shield and the outer ring arm are smoothly connected to reduce the impact loss of the airflow and improve the efficiency of the fan. Along the axial direction of the drive structure, the height difference between the connection between the second inner wall surface and the outer ring arm and the connection between the first protrusion and the inner ring arm is less than or equal to the third threshold value, and the third threshold value is preferably 0mm to 5mm. That is, the connection between the second inner wall surface and the outer ring arm and the connection between the first protrusion and the inner ring arm are approximately at the same height.

[0078] In any of the above technical solutions, preferably, the wind hood also includes: a collecting surface, the diameter of which gradually decreases along the air inlet direction, the air inlet is located at one end of the collecting surface, and the other end of the collecting surface is smoothly transitionally connected to the first inner wall surface; wherein, the end of the impeller facing the air inlet is located in the wind hood.

[0079] In this technical solution, the diameter of the current collecting surface gradually decreases along the air inlet direction, the air inlet is located at one end of the current collecting surface, and the other end of the current collecting surface is smoothly connected to the first inner wall surface, so that the airflow establishes a uniform velocity field and fluid field before entering the flow channel of the impeller, which can effectively improve the efficiency of the fan. Furthermore, the end of the impeller facing the air inlet is located in the wind hood. Specifically, the current collecting surface, the first inner wall surface and the second inner wall surface together constitute the inner wall surface of the wind hood, and the wind hood is a thin-walled structure.

[0080] In any of the above technical solutions, preferably, the driving structure also includes: a bearing assembly, the bearing assembly includes a rotating shaft and a sleeve nested on the rotating shaft, and a plurality of groups of rolling elements arranged between the sleeve and the rotating shaft, the impeller is fixed at one end of the rotating shaft; and the rotor is fixed at the other end of the rotating shaft.

[0081] In this technical solution, the driving structure also includes a bearing assembly and a rotor, the bearing assembly includes a sleeve and multiple groups of rolling elements, the rolling elements are located between the sleeve and the rotating shaft, the rotating shaft passes through the sleeve and the rolling elements, one end is connected to the impeller, and the other end is connected to the rotor, and the rotor is fixed to the lower end of the rotating shaft. Furthermore, the rolling elements are evenly arranged between the sleeve and the rotating shaft along the circumference of the rotating shaft.

[0082] In any of the above technical solutions, preferably, the outer diameter of the sleeve is greater than or equal to 12 mm and less than or equal to 14 mm; the outer diameter of the matching area on the shaft with the sleeve is greater than or equal to 4 mm and less than or equal to 6 mm.

[0083] In this technical solution, the outer diameter of the sleeve is greater than or equal to 12 mm and less than or equal to 14 mm, and accordingly, the outer diameter of the area where the shaft and the sleeve match is greater than or equal to 12 mm and less than or equal to 14 mm. Preferably, the sleeve has an outer cylindrical surface with a diameter of 13 mm, and the portion of the shaft and the sleeve corresponding to each other in the axial direction has an outer cylindrical surface with a diameter of 5 mm.

[0084] In any of the above technical solutions, preferably, the cover plate and the first protrusion are thin-walled structures, the first protrusion defines a first mounting cavity, the cover plate defines a second mounting cavity, a mounting portion is provided in the second mounting cavity, the mounting portion is sleeved on the rotating shaft, and the impeller is fixed to the rotating shaft through the mounting portion; wherein, the rolling body close to the impeller is at least partially located in the second mounting cavity.

[0085] In this technical solution, the cover plate and the first protrusion are both thin-walled structures, so that the interior of the first protrusion defines a first installation cavity, and the interior of the cover plate defines a second installation cavity. The thin-walled structure can ensure the shrinkage consistency during impeller molding, while reducing the rotational inertia of the impeller and improving efficiency. At the same time, under the premise that the axial size allows, the support position is as close to the center of gravity of the impeller as possible, which can reduce the impact of the impeller's imbalance on the bearing, thereby improving the reliability of the component. Furthermore, a mounting portion is also provided in the second installation cavity, and the impeller is fixed on the rotating shaft through the mounting portion. At the same time, the rolling body close to the impeller is at least partially located in the second installation cavity.

[0086] In any of the above technical solutions, preferably, a through hole is provided on the mounting portion, and the through hole is arranged along the axial direction of the mounting portion.

[0087] In this technical solution, a through hole is also provided on the mounting portion, the diameter of which is smaller than the diameter of the mounting holes of the mounting portion and the driving structure, and the through hole penetrates the mounting portion axially. The provision of the through hole, on the one hand, serves as a vent when installing the driving structure, preventing assembly errors caused by the closed hole; and at the same time, it can reduce material and rotational inertia. Specifically, the rotating shaft is fixedly connected to the mounting hole, and the combined length of the rotating shaft and the mounting hole is greater than or equal to 6 mm and less than or equal to 10 mm, so that the axial space is fully utilized while ensuring positioning reliability.

[0088] In any of the above technical solutions, preferably, the number of the rolling elements is two.

[0089] In this technical solution, there are two rolling bodies, which are respectively located at two ends of the shaft sleeve.

[0090] Furthermore, the axial span L between the two groups of rolling elements is between 16 mm and 18 mm.

[0091] Optionally, the axial span L between the two groups of rolling elements is between 10 mm and 12 mm.

[0092] Furthermore, two grooves are axially spaced apart on the outer circumference of the shaft, the span of the two grooves is consistent with the span L of the rolling body, and the two groups of rolling bodies are respectively arranged in the grooves. The raceway of the rolling body is directly opened on the shaft, which can save the radial dimension occupied by the inner ring of the bearing assembly, and the center distance of the rolling body is further reduced while keeping the shaft diameter unchanged, which can effectively increase the limit speed of the bearing.

[0093] Preferably, the center distance of the rolling elements is 6.4 mm.

[0094] Preferably, two grooves are axially spaced apart on the inner circumference of the sleeve, the span of the grooves is consistent with the rolling element span L, and the two groups of rolling elements are respectively arranged in the grooves. The raceway of the rolling element is directly opened on the sleeve, which can save the radial dimension occupied by the outer ring of the bearing assembly, so that the sleeve has a larger thickness and improves the overall rigidity; or further reduce the outer diameter of the sleeve and reduce the weight of the assembly.

[0095] Preferably, the first outer ring and the second outer ring are fixedly arranged inside the two ends of the sleeve, and grooves are arranged on the inner circumferences of the first outer ring and the second outer ring, respectively, and two groups of rolling elements are arranged in the grooves. The outer ring and the sleeve of this structure are assembled, and the axial distance between the two outer rings can be adjusted to control the clearance and apply preload, which reduces the processing accuracy requirements of the sleeve.

[0096] Preferably, the rotating shaft is a through shaft with a diameter of 5 mm, and a plurality of grooves are provided on the through shaft for mounting rolling elements and accommodating adhesives. The through shaft is easier to process than a stepped shaft, and has a higher processing accuracy than a stepped shaft. It can also avoid the local features such as the undercut groove brought by the stepped shaft that are prone to stress concentration, thereby improving the rigidity and strength of the shaft.

[0097] Optionally, the rolling element and the shaft are both made of metal. The bearing assembly made of metal can run stably at a working speed of 150,000 rpm, and is economical.

[0098] Optionally, the shaft is made of metal and the rolling element is made of ceramic. The metal through shaft with a diameter of 5 mm has a certain rigidity and can be applied to the design requirements of most small high-speed fans; the bearing assembly with ceramic balls can operate stably at a working speed of 160,000 rpm to 170,000 rpm, which can increase the limit speed and has a certain economy.

[0099] Preferably, the two groups of rolling bodies have the same number of rolling sub-bodies, which is 6 or 7.

[0100] In any of the above technical solutions, preferably, the diffuser further comprises: a bearing seat, which is sleeved on the shaft sleeve and accommodated in the first installation cavity, the bearing seat is connected to the first protrusion, and at least a part of the bearing seat extends into the second installation cavity.

[0101] In this technical solution, the diffuser also includes a bearing seat, the bearing seat sleeve is arranged on the shaft sleeve, the diffuser is connected to the rotating shaft through the bearing seat, and at least a part of the bearing seat extends into the second installation cavity.

[0102] In any of the above technical solutions, preferably, reinforcing ribs are provided between the bearing seat and the inner ring arm.

[0103] In this technical solution, a number of reinforcing ribs are evenly distributed along the circumferential direction between the bearing seat and the inner ring arm to improve the reliability of the connection.

[0104] In any of the above technical solutions, preferably, the first protrusion, the inner ring arm, the outer ring arm and the bearing seat are an integrated structure.

[0105] In this technical solution, the coaxiality between the impeller and the wind shield must be ensured by the dimension chain between the bearing assembly, the bearing seat, the first notch of the diffuser and the second notch of the wind shield. The quality of the coaxiality will directly affect the uniformity of the tip clearance between the impeller and the wind shield, thereby affecting the efficiency. The bearing seat and the inner ring arm, the outer ring arm and other features are integrally set as a diffuser, so that the above-mentioned dimension chain can be concentrated on as few matching parts as possible, thereby ensuring assembly and high efficiency.

[0106] In any of the above technical solutions, preferably, the rotor comprises: a magnetic ring, sleeved on the rotating shaft; and a protective sleeve, sleeved outside the magnetic ring; wherein a gap is provided between the magnetic ring and the sleeve along the axial direction of the rotating shaft.

[0107] In this technical solution, the rotor includes a magnetic ring formed in an annular shape, and a protective sleeve fixedly mounted on the outer circumference of the magnetic ring. The magnetic ring is fixedly connected to the shaft below the bearing assembly, and there is a gap between the magnetic ring and the shaft sleeve to prevent the rolling element from being magnetized and affecting its service life.

[0108] In any of the above technical solutions, preferably, the gap is greater than or equal to 3 mm.

[0109] In this technical solution, an axial distance of at least 3 mm is retained between the end face of the magnetic ring and the end face of the sleeve to prevent the rolling elements from being magnetized, thereby affecting the life of the bearing assembly.

[0110] Furthermore, the protective cover has an integrally formed reinforcement part and a balancing part. Specifically, the reinforcement part is mainly arranged on the outer peripheral surface of the magnetic ring, has a thickness of 0.2mm to 0.3mm, and is fixed to the end face of the magnetic ring through a spinning process to protect the magnetic ring from disintegration during high-speed operation; the balancing part is arranged at the other end of the magnetic ring away from the spinning part, has a thickness of about 1mm, and plays a role in balancing and deweighting. The integrated protective cover structure can reduce the number of parts, simplify the assembly process, and reduce costs.

[0111] Preferably, the balancing part is arranged on a side away from the sleeve, that is, the balancing part is arranged at the end of the rotor. The balancing part away from the center of gravity of the rotor is convenient for weight removal, which can improve weight removal efficiency and reliability.

[0112] Preferably, the balancing part is arranged on a side close to the shaft sleeve, that is, the balancing part is arranged between the bearing and the magnetic ring. The balancing part close to the center of gravity of the rotor can shorten the axial length and make full use of the axial space.

[0113] Preferably, the protective cover is made of non-magnetic material.

[0114] In any of the above technical solutions, preferably, the fan also includes: a frame, connected to the diffuser and arranged near the air outlet; the stator assembly is connected to the bearing seat through the frame, a first flow path is provided between the stator assembly and the frame, a second flow path is provided between the stator assembly and the rotor, and the first flow path and the second flow path are connected to the air duct.

[0115] In this technical solution, the stator assembly is arranged on the radial outer side of the rotor and is fixedly connected to the bearing seat through a frame. The stator assembly is fixedly arranged on the axial lower side of the diffuser, and at least part of the stator assembly is located in the air duct to improve the heat dissipation effect of the stator assembly. At the same time, there is a first flow path between the stator assembly and the frame, and a second flow path between the stator assembly and the rotor. The first flow path and the second flow path are connected to the air duct to cool the heat-generating components on the flow path.

[0116] Specifically, the stator assembly includes an annular stator yoke and a plurality of stator teeth which are circumferentially spaced on the inner side of the stator yoke and extend radially inward. The stator teeth are formed as an inner surface on the radial inner side, which is clearance-matched with the outer diameter of the rotor and is axially arranged corresponding to the rotor. The stator assembly also includes a winding wound on the yoke, the maximum diameter of the winding is smaller than the maximum diameter of the air duct, and the minimum diameter is larger than the inner surface of the stator teeth.

[0117] Furthermore, the frame has an annular outer shell axially arranged below the outer ring arm, and the outer shell is provided with a stator mounting portion, which fixes and accommodates the stator assembly inward. A first flow path is formed between the inner wall of the outer shell and the winding, which is used to lead the fluid in the air duct out of the fan and cool the stator components on the flow path. At the same time, the space between the stator and the rotor forms a second flow path, which is connected to the air duct through the space on the upper side of the stator assembly, and the fluid in the air duct is introduced between the stator assembly and the rotor to cool the heat-generating components on the flow path.

[0118] In any of the above technical solutions, preferably, the fan further comprises: a control board, which is arranged at one end of the stator assembly away from the diffuser, and at least a part of the control board is located in the first flow path and the second flow path.

[0119] In this technical solution, the airflow in the air duct cools the stator assembly, the rotor and the components on the electronic control board through the first flow path and the second flow path. At the same time, the first flow path and the second flow path are located below the air duct, that is, the high-speed gas is introduced to other heat-generating components for cooling only after the gas has completed diffusion. Therefore, it will not affect the state of the airflow in the air duct, thereby ensuring efficiency while achieving a good heat dissipation design for the entire machine.

[0120] According to a second aspect of the present invention, an electrical device is also proposed, comprising: a fan as proposed in any technical solution of the first aspect.

[0121] The electrical equipment provided in the second aspect of the present invention comprises the fan proposed in any of the above technical solutions and therefore has all the beneficial effects of the fan.

[0122] Specifically, the electrical appliance may be a vacuum cleaner or an air conditioner.

[0123] Additional aspects and advantages of the present invention will become apparent from the following description or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0124] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0125] Figure 1 A cross-sectional view of a fan according to an embodiment of the present invention is shown;

[0126] Figure 2 A schematic structural diagram of a diffuser according to an embodiment of the present invention is shown;

[0127] Figure 3 Another structural schematic diagram of a diffuser according to an embodiment of the present invention is shown;

[0128] Figure 4 A schematic diagram showing the structure of an impeller according to an embodiment of the present invention is shown;

[0129] Figure 5 Another schematic structural diagram of an impeller according to an embodiment of the present invention is shown;

[0130] Figure 6 Another schematic structural diagram of an impeller according to an embodiment of the present invention is shown;

[0131] Figure 7 A partial structural cross-sectional view of a fan according to an embodiment of the present invention is shown;

[0132] Figure 8 A partial structural cross-sectional view of a fan according to another embodiment of the present invention is shown;

[0133] Fig. 9 A schematic diagram of an exploded structure of a fan according to an embodiment of the present invention is shown;

[0134] Fig.10 Another exploded structural schematic diagram of a fan according to an embodiment of the present invention is shown.

[0135] in, Figures 1 to 10 The corresponding relationship between the reference numerals and the component names is as follows:

[0136] 1 impeller, 10 cover plate, 100 second mounting cavity, 12 second blade, 120 leading edge, 122 trailing edge, 124 second inner endpoint, 126 second outer endpoint, 14 raised portion, 16 mounting portion, 160 mounting hole, 162 through hole, 2 diffuser, 20 first convex portion, 22 inner ring arm, 24 outer ring arm, 240 first notch, 26 first blade, 260 inlet end, 262 outlet end, 264 first inner endpoint, 266 first outer endpoint, 28 first mounting cavity, 3 wind shield, 30 air inlet, 32 air outlet, 34 first inner wall, 36 second inner wall, 360 second notch, 38 collecting surface, 4 driving structure, 5 stator assembly, 50 stator yoke, 52 stator tooth, 54 winding, 56 control board, 6 bearing assembly, 60 bushing, 62 rolling element, 64 first outer ring, 66 second outer ring, 68 rotating shaft, 7 bearing seat, 70 reinforcing rib, 8 rotor, 80 magnetic ring, 82 protective cover, 820 reinforcing part, 822 balancing part, 9 frame, 90 outer shell. DETAILED DESCRIPTION

[0137] In order to more clearly understand the above-mentioned purpose, features and advantages of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0138] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited to the specific embodiments disclosed below.

[0139] Refer to the following Figures 1 to 10 The wind turbine and electrical equipment according to some embodiments of the present invention are described.

[0140] According to an embodiment of the first aspect of the present invention, the present invention provides a fan, comprising: a drive structure 4; an impeller 1, the impeller 1 comprising a cover plate 10, the cover plate 10 being mounted on the drive structure 4, the cover plate 10 being recessed in the axial direction of the impeller 1, and the diameter of the cover plate 10 gradually increasing along the air inlet direction; a hood 3, the hood being arranged on the impeller 1, the hood 3 being provided with an air inlet 30 and an air outlet 32 ​​connected to the air inlet 30; a diffuser 2, the diffuser 2 being located at one end of the impeller 1 facing the air outlet 32, the diffuser 2 comprising a first convex portion 20 connected to the drive structure 4, the first The protrusion 20 protrudes toward the wind hood 3, and the diameter of the end of the first protrusion 20 close to the cover plate 10 is smaller than the diameter of the end away from the cover plate 10. The diffuser 2 also includes an inner ring arm 22 connected to the first protrusion 20 and an outer ring arm 24 sleeved on the outside of the inner ring arm 22. The outer ring arm 24 is smoothly connected to the wind hood 3, and the first protrusion 20, the inner ring arm 22, and the outer ring arm 24 are coaxially arranged; wherein, the wind hood 3, the cover plate 10, and the diffuser 2 define an air duct, and the air duct includes a variable cross-section portion and a constant cross-section portion, the variable cross-section portion is arranged close to the air inlet 30, and the constant cross-section portion is arranged close to the air outlet 32.

[0141] like Figure 1 As shown, the fan provided by the present invention includes a driving structure 4, a wind cover 3, an impeller 1 and a diffuser 2. The driving structure 4 drives the impeller 1 to rotate so that the airflow flows from the air inlet 30 to the air outlet 32. The diffuser 2 includes a first protrusion 20, an inner ring arm 22 and an outer ring arm 24 arranged coaxially. The first protrusion 20 is arranged close to the impeller 1, the inner ring arm 22 is connected to the first protrusion 20 and is located below the first protrusion 20, the outer ring arm 24 is sleeved with the inner ring arm 22, the first protrusion 20 protrudes toward the wind cover 3, and the diameter of the first protrusion 20 gradually increases. The wind cover 3, the impeller 1 and the diffuser 2 define an air duct, and the airflow flows from the air inlet 30 to the air outlet 32 ​​through the air duct. The impeller 1 and the wind cover 3 The space formed between changes the direction and kinetic energy of the fluid, and when passing through the air duct formed between the first convex portion 20 and the wind hood 3, the dynamic pressure is converted into static pressure. At the same time, the fluid is guided radially outward and downward, and the airflow in the entire air duct flows very smoothly, reducing the impact loss and separation loss. The wall surface of the wind hood 3 and the wall surface of the diffuser 2 are connected by a smooth transition, that is, the diameter of the connected part between the wall surface of the wind hood 3 and the wall surface of the diffuser 2 is the same. Furthermore, the inner wall surface of the wind hood 3 and the inner wall surface of the diffuser 2 are connected by a smooth transition, so that the airflow will not generate impact when passing through the connection between the wind hood 3 and the diffuser 2, thereby reducing the impact loss at the connection and improving the efficiency of the fan.

[0142] Furthermore, the air duct includes a variable cross-section portion and a constant cross-section portion, the variable cross-section portion is close to the air inlet 30, and the constant cross-section portion is close to the air outlet 32, and along the air inlet direction, the cross-sectional area of ​​the variable cross-section portion gradually decreases, and the cross-sectional area of ​​the constant cross-section portion remains unchanged, and the variable cross-section portion and the constant cross-section portion are smoothly transitioned and connected, so that the airflow flows very smoothly in the air duct, reducing impact loss and separation loss.

[0143] Furthermore, the space between the impeller 1 and the wind cover 3 constitutes a variable cross-section portion, and the space between the diffuser 2 and the wind cover 3 constitutes a constant cross-section portion.

[0144] Furthermore, the airflow enters the air duct from the air inlet 30 roughly along the axial direction of the driving structure 4, and the distance between the center line of the air duct and the axis of the driving structure 4 gradually increases, so that the airflow is gradually guided radially outward and downward of the driving structure 4 when passing through the air duct.

[0145] Furthermore, the air cover 3, the impeller 1 and the diffuser 2 are all coaxially arranged, and the wall surface of the first convex portion 20 facing the air cover 3 is a smooth convex surface with a gradually increasing diameter.

[0146] Specifically, Figure 1 The direction indicated by the arrow is the flow direction of the airflow.

[0147] In any of the above embodiments, preferably, the driving structure 4 includes: a stator assembly 5, which is arranged relative to the air outlet 32 ​​so that the wind flowing out of the air outlet 32 ​​blows directly toward the stator assembly 5. In this technical solution, the driving structure 4 includes the stator assembly 5, which is arranged at the air outlet 32, and then the wind flowing out of the air outlet 32 ​​blows directly toward the stator assembly 5, thereby improving the heat dissipation effect of the stator assembly 5.

[0148] In any of the above embodiments, preferably, an angle between an extension direction of one end of the cover plate 10 toward the first protrusion 20 and an extension direction of the first protrusion 20 toward one end of the cover plate 10 is less than or equal to a first threshold.

[0149] In this embodiment, the angle between the extension direction of one end of the cover plate 10 toward the first protrusion 20 and the extension direction of the first protrusion 20 toward one end of the cover plate 10 is less than or equal to a first threshold value, that is, the angle between the tangent passing through the end circumference of the first protrusion 20 and the tangent passing through the end circumference of the cover plate 10 is less than or equal to the first threshold value, so that the angle between the flow direction of the airflow when passing through the cover plate 10 toward the end of the first protrusion 20 and the flow direction of the airflow when passing through the first protrusion 20 toward the end of the cover plate 10 is less than or equal to the first threshold value, and the value of the first threshold value can be between -2° and 2°. Of course, the first threshold value can also be other smaller angles, that is, the end of the first protrusion 20 is roughly arranged in the tangent direction of the end of the cover plate 10, so that the transition between the first protrusion 20 and the end of the cover plate 10 is smoother, and the impact loss is greatly reduced when the airflow passes through the connection between the first protrusion 20 and the cover plate 10, thereby improving the efficiency of the fan.

[0150] Furthermore, the diameter of the end of the first protrusion 20 facing the air inlet 30 is greater than or equal to the diameter of the end of the impeller 1 facing the air outlet 32, that is, of the two ends close to the first protrusion 20 and the impeller 1, the end of the first protrusion 20 is larger than the end of the impeller 1, so that the airflow is gradually guided radially outward and downward of the driving structure 4 when flowing from the impeller 1 to the first protrusion 20.

[0151] In any of the above embodiments, preferably, an annular recessed portion is provided at one end of the first convex portion 20 facing the air inlet 30 , and an annular raised portion 14 is provided at one end of the cover plate 10 facing the diffuser 2 , and the recessed portion and the raised portion 14 are clearance-matched.

[0152] like Figure 1 As shown, in this embodiment, a recessed portion is provided on the first convex portion 20, and a raised portion 14 is provided on the cover plate 10, and the recessed portion and the raised portion 14 are adapted to each other. Since the cover plate 10 rotates at a high speed and the diffuser 2 is fixedly arranged, the two must be clearance-matched. Further, the gap between the recessed portion and the raised portion 14 is smaller than a predetermined threshold value, that is, the recessed portion and the raised portion 14 are fitted with a small gap. When the fluid flows from the cover plate 10 to the first convex surface, it is inevitable that the fluid will enter the gap between the two and cause leakage loss. The small gap fit can reduce such leakage, thereby improving efficiency. At the same time, the raised portion 14 is located below the cover plate 10 and can be used as a balance ring of the cover plate 10 for balancing and deweighting, and there is no need to separately set a balance ring of the cover plate 10, thereby reducing the number of parts, simplifying the assembly process, and reducing costs.

[0153] In any of the above embodiments, preferably, the diameter of the connection between the first protrusion 20 and the inner ring arm 22 is the same as the diameter of the outer wall surface of the inner ring arm 22 and the connection is smoothly transitioned.

[0154] In this embodiment, the diameter of the connection between the first protrusion 20 and the inner ring arm 22 is the same as the diameter between the outer wall surfaces of the inner ring arm 22. Furthermore, the connection between the first protrusion 20 and the inner ring arm 22 is a smooth transition connection, thereby reducing the impact loss of the airflow when passing through the connection between the first protrusion 20 and the inner ring arm 22, thereby improving the working efficiency of the fan.

[0155] In any of the above embodiments, preferably, a first notch 240 is provided on the side of the outer ring arm 24 facing away from the axis of the driving structure 4, and a second notch 360 matching the first notch 240 is provided on the side of the wind cover 3 facing the axis of the driving structure 4, the first notch 240 and the second notch 360 are both annular, and the side of the outer ring arm 24 facing the air inlet 30 abuts against the bottom of the second notch 360.

[0156] like Figure 2 As shown, in this embodiment, a first notch 240 is provided on the outer side of the outer ring arm 24, and a second notch 360 is provided on the inner side of the corresponding position of the wind hood 3, and the first notch 240 cooperates with the second notch 360. Furthermore, the depth of the second notch 360 along the radial direction of the first protrusion 20 is equal to the remaining thickness of the outer ring arm 24 after the first notch 240 is provided, so that a smooth transition connection is achieved between the connected wind hood 3 and the outer ring arm 24. At the same time, through the cooperation of the first notch 240 and the second notch 360, the radial positioning of the wind hood 3 and the diffuser 2 is achieved, and the coaxiality of the diffuser 2 and the wind hood 3 is ensured.

[0157] Furthermore, the first notch 240 and the second notch 360 are both annular in shape, and the side of the outer ring arm 24 facing the air inlet 30 abuts against the bottom of the second notch 360 .

[0158] In this embodiment, the first notch 240 and the second notch 360 are both annular, thereby improving the reliability of the connection between the diffuser 2 and the wind hood 3. The side of the outer ring arm 24 facing the air inlet 30 abuts against the bottom of the second notch 360, that is, the top of the outer ring arm 24 abuts against the bottom of the groove of the second notch 360, thereby realizing the axial positioning of the diffuser 2 and the wind hood 3, and at the same time ensuring the smooth transition connection between the inner wall surface of the wind hood 3 and the inner wall surface of the outer ring arm 24, thereby ensuring the smoothness of the medium flow.

[0159] In any of the above embodiments, preferably, the diffuser 2 also includes: a first blade 26, which is arranged between the inner ring arm 22 and the outer ring arm 24, and the two ends of the first blade 26 along the radial direction of the diffuser 2 are respectively attached to the inner ring arm 22 and the outer ring arm 24, so that the first blade 26 and the inner ring arm 22 and the outer ring arm 24 form an air guide cavity; wherein the first blade 26 is spiral-shaped, and along the air inlet direction the first blade 26 includes an inlet end 260 and an outlet end 262, and along the rotation direction of the impeller 1, the inlet end 260 is located behind the outlet end 262.

[0160] like Figure 2 and Figure 3 As shown, in this embodiment, the diffuser 2 also includes a first blade 26, which is arranged between the inner ring arm 22 and the outer ring arm 24, wherein the two ends of the first blade 26 along the radial direction of the diffuser 2 are respectively attached to the inner ring arm 22 and the outer ring arm 24, that is, the first blade 26 extends to the inner ring arm 22 in the axial direction of the diffuser 2, and extends to the outer ring arm 24 away from the axial direction of the diffuser 2, so that the root of the first blade 26 is attached to the inner ring arm 22, and the top is attached to the outer ring arm 24, so that an air guide cavity is formed between the inner ring arm 22, the first blade 26, and the outer ring arm 24, and the air guide cavity formed by the annular space between the inner ring arm 22 and the outer ring arm 24 and the first blade 26 is relatively closed. After the airflow enters the air guide cavity, it only flows out from the outlet of the air guide cavity, thereby avoiding the efficiency loss caused by the sealing leakage of the first blade 26 during the diffusion process, and also simplifying the assembly process. The first blade 26 is spiral-shaped, and along the rotation direction of the impeller 1 , the inlet end 260 is located behind the outlet end 262 , which is beneficial to reducing the along-the-way loss of the airflow and the impact loss at the outlet end 262 .

[0161] In any of the above embodiments, preferably, the first blade 26 is completely located in the wind cavity between the inner ring arm 22 and the outer ring arm 24 .

[0162] In this embodiment, the first blade 26 is completely located in the air guide cavity in the axial direction, that is, the first blade 26 is completely located in the annular wind cavity formed by the inner ring arm 22 and the outer ring arm 24, which can ensure the uniformity of the airflow at the inlet end 260 and the outlet end 262 of the first blade 26 and avoid the influence of other structures on the airflow.

[0163] In any of the above embodiments, preferably, the angle between the extension direction of the inlet end 260 and the radial direction of the inner ring arm 22 is less than or equal to a second threshold; the outlet end 262 includes a first inner end point 264 connected to the inner ring arm 22 and a first outer end point 266 connected to the outer ring arm 24, and along the rotation direction of the impeller 1, the first inner end point 264 is located in front of the first outer end point 266.

[0164] like Figure 2 As shown, in this embodiment, the extension direction of the inlet end 260, that is, the extension direction of the inlet end 260 from the inner ring arm 22 to the outer ring arm 24, the angle between the extension direction of the inlet end 260 and the radial direction of the inner ring arm 22 is less than or equal to a second threshold value, and the value range of the second threshold value may be determined according to the specific circumstances, such as -2° to 2° or other suitable values, that is, the inlet end 260 is roughly arranged in the radial extension line direction of the inner ring arm 22; the first inner end point 264 of the outlet end 262 is located in front of the first outer end point 266, that is, the first inner end point 264 is in front of the first outer end point 266.

[0165] In any of the above embodiments, preferably, along the axial direction of the diffuser 2, the inlet end 260 is a smooth curved surface convex toward the impeller 1, and the outlet end 262 is a smooth curved surface convex away from the impeller 1; along the rotation direction of the impeller 1, of the two side surfaces of the first blade 26, the side surface located in the front is convex in the rotation direction of the impeller 1, and the side surface located in the rear is concave in the rotation direction of the impeller 1.

[0166] In this embodiment, along the axial direction of the diffuser 2, the inlet end 260 is a smooth curved surface convex toward the impeller 1, and the outlet end 262 is a smooth curved surface convex away from the impeller 1, thereby ensuring the uniformity of the airflow at the inlet end 260 and reducing the impact loss at the outlet end 262. Along the rotation direction of the impeller 1, of the two side surfaces of the first blade 26, the side surface located in the front, that is, the pressure surface of the first blade 26, is convex toward the rotation direction of the impeller 1, and the side surface located in the rear, that is, the back pressure surface of the first blade 26, is concave toward the rotation direction of the impeller 1, which is beneficial to reducing the along-the-way loss of the airflow and further beneficial to improving the efficiency of the fan.

[0167] In any of the above embodiments, preferably, the inner ring arm 22, the first blade 26 and the outer ring arm 24 are an integrated structure.

[0168] In this embodiment, the inner ring arm 22 and the outer ring arm 24 are in the shape of a circular ring, wherein the outer ring arm 24 is arranged radially outside the inner ring arm 22, and the spiral first blade 26 is arranged between the inner ring arm 22 and the outer ring arm 24, and is connected with the inner ring arm 22 and the outer ring arm 24 to form an integral part. Since the two ends of the first blade 26 along the radial direction of the inner ring arm 22 are respectively attached to the inner ring arm 22 and the outer ring arm 24, the first blade 26 and the inner ring arm 22 and the outer ring arm 24 can be easily molded as an integral part, without the need to make the first blade 26 integrally formed with one of the inner ring arm 22 and the outer ring arm 24 and then assembled and connected with the other. The setting of the integral diffuser 2 can form a sealed air guide cavity between the relatively arranged cylindrical surfaces of the inner ring arm 22 and the outer ring arm 24 and the relatively arranged pressure surfaces and back pressure surfaces of the two adjacent first blades 26, thereby avoiding the efficiency loss caused by the leakage of the first blade 26 during the diffusion process, and also simplifying the assembly process.

[0169] In any of the above embodiments, preferably, there are multiple first blades 26 , and the multiple first blades 26 are evenly distributed between the inner ring arm 22 and the outer ring arm 24 along the circumferential direction of the inner ring arm 22 .

[0170] In this embodiment, there are a plurality of first blades 26 , and the plurality of first blades 26 are evenly distributed between the inner ring arm 22 and the outer ring arm 24 along the circumferential direction of the inner ring arm 22 . Furthermore, there are twelve first blades 26 .

[0171] In any of the above embodiments, preferably, the impeller 1 also includes: a second blade 12, which is arranged on the cover plate 10, and the second blade 12 is located in the air duct; wherein, along the air inlet direction, the second blade 12 includes a leading edge 120 close to the air inlet 30 and a trailing edge 122 close to the air outlet 32, and along the rotation direction of the impeller 1, the leading edge 120 is located in front of the trailing edge 122.

[0172] like Figure 4 As shown, in this embodiment, the impeller 1 also includes a second blade 12, and the outer wall surface of the cover plate 10 is a smooth concave surface, wherein the airflow enters the air duct from the air inlet 30, obtains a relatively uniform flow field, and then enters the independent flow channel space formed by two adjacent second blades 12 through the leading edge 120, thereby avoiding the influence of the flow field change at the inlet end on the fluid movement between the second blades 12. The leading edge 120 is located in front of the trailing edge 122, so that the extension direction of the flow channel space between the two adjacent second blades 12 is the same as the rotation direction of the impeller 1.

[0173] Furthermore, the second blade 12 intersects with the outer wall surface of the cover plate 10 to form a blade root, and the second blade 12 extends away from the outer wall surface of the cover plate 10 and forms a blade top at the maximum outer diameter.

[0174] In any of the above embodiments, preferably, the diameter of the cover plate 10 gradually increases along the air inlet direction.

[0175] In this embodiment, the diameter of the cover plate 10 gradually increases along the air inlet direction. Furthermore, the outer wall surface of the cover plate 10 is a smooth concave surface with a gradually increasing diameter.

[0176] In any of the above embodiments, preferably, the angle α between the extension direction of the leading edge 120 and the axial direction of the driving structure 4 is in the range of 76°±2°; the trailing edge 122 is located on the cylindrical surface formed by the outer side wall of the raised portion 14 .

[0177] like Figure 8 As shown, in this embodiment, the angle α between the imaginary straight line where the leading edge 120 is located and the axis of the cover plate 10 is in the range of 76°±2°, so that the leading edge 120 is roughly arranged along the radial direction of the cover plate 10. Specifically, the angle α between the imaginary straight line where the leading edge 120 is located and the axis of the cover plate 10 is greater than or equal to 74° and less than or equal to 78°; the trailing edge 122 is located on the cylindrical surface formed by the outer side wall of the raised portion 14, thereby reducing the impact loss of the airflow when passing through the trailing edge 122.

[0178] In any of the above embodiments, preferably, the leading edge 120 includes a second inner endpoint 124 connected to the cover plate 10 and a second outer endpoint 126 away from the cover plate 10, along the rotation direction of the impeller 1, the second outer endpoint 126 is located before the second inner endpoint 124, from the air outlet 32 ​​to the air inlet 30, the second inner endpoint 124 is located below the second outer endpoint 126, and the second outer endpoint 126 is located at the end of the cover plate 10 facing the air inlet 30 and below the air inlet 30; the trailing edge 122 includes a third inner endpoint connected to the cover plate 10 and a third outer endpoint away from the cover plate 10, the third inner endpoint is located on the circumference of one end of the impeller 1 facing the diffuser 2, and from the air outlet 32 ​​to the air inlet 30, the third outer endpoint is located above the third inner endpoint.

[0179] like Figures 4 to 7 As shown, in this embodiment, since the leading edge 120 starts from the root of the leading edge 120 and extends radially outward and upward of the cover plate 10, the airflow flows into the flow channel formed by the second blade 12 in an inclined direction, which effectively controls the air volume and air pressure of the leading edge 120 and reduces the loss of the fluid at the leading edge 120. At the same time, the second outer end point 126 is arranged above the second inner end point 124, which can ensure that the streamline length of the top of the second blade 12 is slightly greater than the streamline length of the root of the second blade 12, so that the airflow has a relatively uniform flow state at the trailing edge 122. Specifically, the second inner end point 124 The second outer endpoint 126 is the two endpoints at the intersection of the pressure surface or back pressure surface of the second blade 12 and the cover plate 10; the second outer endpoint 126 is located at the end of the cover plate 10 facing the air inlet 30 and below the air inlet 30, avoiding the leakage loss of air flow entering the air duct; the connection between the trailing edge 122 and the cover plate 10 is located on the circumference of one end of the impeller 1 facing the diffuser 2, so that the airflow can flow smoothly out of the flow channel formed by the second blade 12, the third outer endpoint is located above the third inner endpoint, and the inclination angle of the trailing edge 122 is reasonably set, which is beneficial to reducing the fluid loss at the outlet end 262.

[0180] Specifically, the extending direction of the leading edge 120 is the connecting direction between the second inner endpoint 124 and the second outer endpoint 126 , and the extending direction of the trailing edge 122 is the extending direction from the root of the trailing edge 122 to the top of the trailing edge 122 .

[0181] In any of the above embodiments, preferably, in the projection of the impeller 1 on the plane perpendicular to the axis of the driving structure 4, the angle γ1 between the line connecting the second inner end point 124 and the axis center of the driving structure 4 and the line connecting the second outer end point 126 and the axis center of the driving structure 4 is greater than or equal to 0° and less than or equal to 5°.

[0182] like Figure 5As shown, in this embodiment, the angle γ1 between the line connecting the second inner end point 124 and the axis, and the line connecting the second outer end point 126 and the axis is greater than or equal to 0° and less than or equal to 5°, and the small leading angle at the top of the leading edge 120 is conducive to fitting the fluid drainage, while ensuring the manufacturability of the impeller 1.

[0183] In any of the above embodiments, preferably, in the projection of the impeller 1 on the plane perpendicular to the axis of the driving structure 4, the angle γ2 between the line connecting the third inner end point and the axis center of the driving structure 4 and the line connecting the third outer end point and the axis center of the driving structure 4 is greater than or equal to -2° and less than or equal to 2°.

[0184] like Figure 5 As shown, in this embodiment, the inclination angle of the trailing edge 122 is reasonably set, which is conducive to reducing the fluid loss at the outlet of the impeller 1, can reduce the gap leakage at the outlet of the impeller 1, reduce the secondary flow at the outlet of the impeller 1 and the existence of the jet wake, and improve the efficiency of the impeller 1. Preferably, the angle γ2 between the line connecting the third inner end point and the axis of the drive structure 4 and the line connecting the third outer end point and the axis of the drive structure 4 is greater than or equal to -2° and less than or equal to 2°, that is, the top of the trailing edge 122 is roughly set in the axial direction of the root of the trailing edge 122.

[0185] In any of the above embodiments, preferably, the leading edge 120 protrudes toward the air inlet 30 , and the length of the trailing edge 122 is smaller than the length of the leading edge 120 .

[0186] In this embodiment, the leading edge 120 is a smooth curved surface that bulges toward the air inlet 30, smoothly connecting the pressure surface and the suction surface. The second blade 12 extends forward toward the air inlet 30 and becomes thinner, which can increase the length of the second blade 12 while reducing the relative diffusion speed. The length of the trailing edge 122 is less than the length of the leading edge 120, which can effectively control the ratio of the inlet and outlet areas of the flow channels between adjacent second blades 12, reduce the diffusion loss of the flow, broaden the range of the high-efficiency zone under small flow conditions, and reduce aerodynamic noise.

[0187] In any of the above embodiments, preferably, the ratio of the length of the trailing edge 122 to the length of the leading edge 120 is greater than or equal to 0.4 and less than or equal to 0.46.

[0188] In this embodiment, the length of the trailing edge 122 is reasonably set, which is conducive to reducing the fluid loss at the outlet end 262, can reduce the gap leakage at the outlet of the impeller 1, reduce the secondary flow and the jet wake at the outlet of the impeller 1, and improve the efficiency of the impeller 1. Preferably, the ratio of the length of the trailing edge 122 to the length of the leading edge 120 is greater than or equal to 0.4 and less than or equal to 0.46.

[0189] Further, the thickness of the leading edge 120 is smaller than the thickness of the trailing edge 122 .

[0190] In any of the above embodiments, preferably, there is a first gap between the end of the second blade 12 away from the axis of the impeller 1 and the inner wall surface of the wind cover 3; wherein the first gap is equidistantly arranged from the air inlet 30 to the air outlet 32, or the first gap gradually decreases from the air inlet 30 to the air outlet 32.

[0191] In this embodiment, since the impeller 1 and the wind cover 3 rotate at a relatively high speed, a clearance is required between the two to ensure that the clearance is gradually reduced from top to bottom or is equidistantly arranged from top to bottom, which can effectively improve the efficiency of the fan.

[0192] In any of the above embodiments, preferably, the first gap is greater than or equal to 0.2 mm and less than or equal to 0.3 mm.

[0193] In this embodiment, if the first gap is too large, the efficiency of the air duct will be seriously affected, and if the first gap is too small, the assembly difficulty will be greatly increased. The first gap is most appropriately selected to be between 0.2 mm and 0.3 mm. At the same time, since the length of the leading edge 120 is greater than the length of the trailing edge 122, the effect of the first gap on the efficiency at the trailing edge 122 is greater than that at the leading edge 120. Therefore, ensuring that the first gap is gradually reduced from top to bottom can effectively improve the efficiency of the fan.

[0194] In any of the above embodiments, preferably, there are multiple second blades 12 , and the multiple second blades 12 are evenly arranged on the cover plate 10 along the circumference of the cover plate 10 .

[0195] In this embodiment, there are multiple second blades 12 , and the multiple second blades 12 are evenly arranged on the cover plate 10 along the circumference of the cover plate 10 .

[0196] Specifically, Figure 6 As shown, the projection of the root of the second blade 12 on the plane in the direction perpendicular to the axis satisfies: the wrap angle θ1 is within the range of 120°±3°; the projection of the top of the second blade 12 on the plane in the direction perpendicular to the axis satisfies: the wrap angle θ2 is within the range of 123°±3°. Specifically, the root of the second blade 12 is the intersection of the second blade 12 and the cover plate 10, and the top of the second blade 12 is the end of the second blade 12 away from the cover plate 10. The wrap angle θ1 is the angle between the two end points of the projection of the root of the second blade 12 on the plane in the direction perpendicular to the axis and the axis center, and the wrap angle θ2 is the angle between the two end points of the projection of the top of the second blade 12 on the plane in the direction perpendicular to the axis and the axis center.

[0197] Preferably, θ2 ≥ θ1.

[0198] Specifically, the larger the wrap angle of the second blade 12, the smaller the flow separation and vortex in the flow channel, the closer the flow is to the second blade 12 profile, and the higher the speed of the impeller 1 under the same impeller 1 diameter; but an excessively large wrap angle of the second blade 12 will cause greater friction loss, and the high efficiency point will move toward the direction of small flow, which will also cause demolding difficulties. The wrap angle range given in the present invention can make the impeller 1 work efficiently within the speed range of 100000rpm to 150000rpm.

[0199] Preferably, if Figure 6 As shown, the projection of the root of the second blade 12 on the plane in the direction perpendicular to the axis satisfies: the inlet placement angle β1 is within the range of 23.5°±3°; the outlet placement angle β2 is within the range of 33.5±3°; the projection of the top of the second blade 12 on the plane in the direction perpendicular to the axis satisfies: the inlet placement angle β3 is within the range of 0° to 3°; the outlet placement angle β4 is within the range of 28.5±3°.

[0200] Specifically, the choice of the inlet placement angle will affect the quality of the flow state when the fluid enters the flow channel of the impeller 1. The appropriate inlet placement angle can reduce the displacement effect of the inlet at the root of the second blade 12, increase the flow area, and avoid serious flow separation at the inlet end of the suction surface, thereby reducing the flow loss. The choice of the outlet placement angle will affect the vacuum degree of the fan. Reducing the outlet placement angle while reducing the outer diameter of the impeller 1 is an effective measure to improve the efficiency of the centrifugal fan. Since the operating speed of the impeller 1 of this embodiment can reach 150,000 rpm, an excessively large diameter of the impeller 1 will cause insufficient structural strength and the influence of unbalanced mass on the rotor assembly, but a too small outlet placement angle will affect the manufacturability of the product. The selection of the above-mentioned inlet placement angle and outlet placement angle can keep the inlet and outlet fluid states of the impeller 1 uniform within the speed range of 100,000 rpm to 150,000 rpm, reduce fluid loss, improve the vacuum degree and efficiency of the fan, and reduce the outer diameter of the impeller 1 to ensure strength and manufacturability.

[0201] Preferably, the maximum diameter of the impeller 1 does not exceed 32 mm.

[0202] Preferably, if Figure 8 As shown, the outer wall surface of the cover plate 10 is formed into a smooth concave surface, the upper end inflow angle δ1 of the outer wall surface of the cover plate 10 is within the range of 4°±2°, and the lower end outflow angle δ2 is within the range of 57.5°±2°.

[0203] Preferably, the thickness of the second blade 12 gradually increases from the leading edge 120 to the trailing edge 122 , and the ratio of the thickness of the leading edge 120 to the thickness of the trailing edge 122 is not less than 80%.

[0204] Preferably, seven second blades 12 are distributed on the impeller 1 at equal intervals along the circumferential direction.

[0205] In any of the above embodiments, preferably, the inner wall surface of the wind hood 3 includes a first inner wall surface 34 corresponding to the cover plate 10 and a second inner wall surface 36 corresponding to the first protrusion 20, the first inner wall surface 34 protrudes from the outer side of the wind hood 3 toward the axial direction of the wind hood 3, and the second inner wall surface 36 is recessed from the axis of the wind hood 3 toward the outer side of the wind hood 3; wherein the first inner wall surface 34, the second inner wall surface 36, the outer wall surface of the cover plate 10, the outer wall surface of the first protrusion 20, the outer wall surface of the inner ring arm 22, and the inner wall surface of the outer ring arm 24 constitute an air duct.

[0206] like Figure 1 As shown, in this embodiment, the inner wall surface of the wind hood 3 includes a first inner wall surface 34 and a second inner wall surface 36, the first inner wall surface 34 is arranged corresponding to the cover plate 10, and the second inner wall surface 36 is arranged corresponding to the first protrusion 20, and the first inner wall surface 34 is a smooth convex surface, and the second inner wall surface 36 is a smooth concave surface, so as to form a variable cross-section portion and a constant cross-section portion with the cover plate 10 and the first protrusion 20 as well as the inner ring arm 22 and the outer ring arm 24. Specifically, the first inner wall surface 34, the second inner wall surface 36, the outer wall surface of the cover plate 10, the outer wall surface of the first protrusion 20, the outer wall surface of the inner ring arm 22, and the inner wall surface of the outer ring arm 24 constitute an air duct.

[0207] In any of the above embodiments, preferably, along the air inlet direction, the diameter of the first inner wall surface 34 and the diameter of the second inner wall surface 36 gradually increase.

[0208] In this embodiment, the diameter of the inner wall surface of the wind shield 3 gradually increases along the wind inlet direction.

[0209] In any of the above embodiments, preferably, the diameter of the connection between the second inner wall surface 36 and the outer ring arm 24 is the same as the diameter of the inner wall surface of the outer ring arm 24; along the axial direction of the driving structure 4, the height difference between the connection between the second inner wall surface 36 and the outer ring arm 24, and the connection between the first protrusion 20 and the inner ring arm 22 is less than or equal to a third threshold.

[0210] like Figure 1 As shown, in this embodiment, the diameter of the connection between the second inner wall surface 36 and the outer ring arm 24 is the same as the diameter of the inner wall surface of the outer ring arm 24 so that the inner wall surface of the wind shield 3 and the outer ring arm 24 are smoothly connected to each other, so as to reduce the impact loss of the airflow and improve the efficiency of the fan. Along the axial direction of the driving structure 4, the height difference between the connection between the second inner wall surface 36 and the outer ring arm 24 and the connection between the first protrusion 20 and the inner ring arm 22 is less than or equal to the third threshold value, and the third threshold value is preferably 0mm to 5mm. That is, the connection between the second inner wall surface 36 and the outer ring arm 24 and the connection between the first protrusion 20 and the inner ring arm 22 are approximately at the same height.

[0211] In any of the above embodiments, preferably, the wind hood 3 also includes: a collecting surface 38, the diameter of the collecting surface 38 gradually decreases along the air inlet direction, the air inlet 30 is located at one end of the collecting surface 38, and the other end of the collecting surface 38 is smoothly transitionally connected to the first inner wall surface 34; wherein, the end of the impeller 1 facing the air inlet 30 is located in the wind hood 3.

[0212] like Figure 1 As shown, in this embodiment, along the air inlet direction, the diameter of the collecting surface 38 gradually decreases, the air inlet 30 is located at one end of the collecting surface 38, and the other end of the collecting surface 38 is smoothly connected with the first inner wall surface 34, so that the airflow establishes a uniform velocity field and fluid field before entering the flow channel of the impeller 1, which can effectively improve the efficiency of the fan. Further, the end of the impeller 1 facing the air inlet 30 is located in the wind cover 3. Specifically, the collecting surface 38, the first inner wall surface 34 and the second inner wall surface 36 together constitute the inner wall surface of the wind cover 3, and the wind cover 3 is a thin-walled structure.

[0213] In any of the above embodiments, preferably, the driving structure 4 also includes: a bearing assembly 6, the bearing assembly 6 includes a rotating shaft 68 and a sleeve 60 nested on the rotating shaft 68, and a plurality of groups of rolling bodies 62 arranged between the sleeve 60 and the rotating shaft 68, the impeller 1 is fixed at one end of the rotating shaft 68; and the rotor 8 is fixed at the other end of the rotating shaft 68.

[0214] like Fig. 9 and Fig.10 As shown, in this embodiment, the driving structure 4 further includes a bearing assembly 6 and a rotor 8. The bearing assembly 6 is accommodated in the first installation cavity 28 and partially extends into the second installation cavity 100. The bearing assembly 6 includes a sleeve 60 and a plurality of rolling bodies 62. The rolling bodies 62 are located between the sleeve 60 and the rotating shaft 68. The rotating shaft 68 passes through the sleeve 60 and the rolling bodies 62, one end of which is connected to the impeller 1, and the other end is connected to the rotor 8. The rotor 8 is fixed to the lower end of the rotating shaft 68. Further, the rolling bodies 62 are evenly arranged between the sleeve 60 and the rotating shaft 68 along the circumference of the rotating shaft 68.

[0215] In any of the above embodiments, preferably, the outer diameter of the sleeve 60 is greater than or equal to 12 mm and less than or equal to 14 mm; the outer diameter of the matching area of ​​the shaft 68 with the sleeve 60 is greater than or equal to 4 mm and less than or equal to 6 mm.

[0216] In this embodiment, the outer diameter of the sleeve 60 is greater than or equal to 12 mm and less than or equal to 14 mm, and accordingly, the outer diameter of the area where the shaft 68 cooperates with the sleeve 60 is greater than or equal to 12 mm and less than or equal to 14 mm. Preferably, the sleeve 60 has an outer cylindrical surface with a diameter of 13 mm, and the portion of the shaft 68 corresponding to the sleeve 60 axially has an outer cylindrical surface with a diameter of 5 mm.

[0217] In any of the above embodiments, preferably, the cover plate 10 and the first protrusion 20 are thin-walled structures, the first protrusion 20 defines a first mounting cavity 28, the cover plate 10 defines a second mounting cavity 100, a mounting portion 16 is provided in the second mounting cavity 100, the mounting portion 16 is sleeved on the rotating shaft 68, and the impeller 1 is fixed on the rotating shaft 68 through the mounting portion 16; wherein, the rolling body 62 close to the impeller 1 is at least partially located in the second mounting cavity 100.

[0218] like Figure 7 and Figure 8 As shown, in this embodiment, the cover plate 10 and the first protrusion 20 are both thin-walled structures, so that the interior of the first protrusion 20 defines a first installation cavity 28, and the interior of the cover plate 10 defines a second installation cavity 100. The thin-walled structure can ensure the shrinkage consistency of the impeller 1 during molding, while reducing the moment of inertia of the impeller 1 and improving efficiency. At the same time, under the premise that the axial size allows, the support position is as close to the center of gravity of the impeller 1 as possible, which can reduce the impact of the unbalanced amount of the impeller 1 on the bearing, thereby improving the reliability of the component. Further, the mounting portion 16 is arranged in the second installation cavity 100 and does not exceed the second installation cavity 100. The cover plate 10 is installed on the drive structure 4 through the mounting portion 16, and the rolling body 62 close to the impeller 1 is at least partially located in the second installation cavity 100, which is conducive to improving the efficiency of the fan.

[0219] In any of the above embodiments, preferably, a through hole 162 is provided on the mounting portion 16 , and the through hole 162 is provided along the axial direction of the mounting portion 16 .

[0220] like Figure 7 As shown, in this embodiment, a through hole 162 is also provided on the mounting portion 16. The diameter of the through hole 162 is smaller than the diameter of the mounting hole 160 of the mounting portion 16 and the driving structure 4, and the through hole 162 penetrates the mounting portion 16 in the axial direction. The provision of the through hole 162, on the one hand, plays a role in venting air when installing the driving structure 4, and prevents the closed hole from causing assembly errors; at the same time, it can reduce the material and the moment of inertia. The rotating shaft 68 is fixedly connected in the mounting hole 160, and the combined length of the rotating shaft 68 and the mounting hole 160 is greater than or equal to 6 mm and less than or equal to 10 mm. Under the premise of ensuring the positioning reliability, the axial space is fully utilized.

[0221] In any of the above embodiments, preferably, the number of the rolling bodies 62 is two.

[0222] like Figure 7 and Figure 8 As shown, in this embodiment, there are two rolling bodies 62 , which are respectively located at two ends of the shaft sleeve 60 , and the rolling body 62 close to the impeller 1 is at least partially located in the second installation cavity 100 .

[0223] Furthermore, if Figure 7As shown, the axial span L between the two groups of rolling elements 62 is between 16 mm and 18 mm.

[0224] Alternatively, if Figure 7 As shown, the axial span L between the two groups of rolling elements 62 is between 10 mm and 12 mm.

[0225] Furthermore, two grooves are axially spaced apart on the outer circumference of the rotating shaft 68, and the span of the two grooves is consistent with the span L of the rolling body 62, and the two groups of rolling bodies 62 are respectively arranged in the grooves. The raceway of the rolling body 62 is directly opened on the shaft, which can save the radial dimension occupied by the inner ring of the bearing assembly 6, and the center distance of the rolling body 62 is further reduced while keeping the shaft diameter unchanged, which can effectively increase the limit speed of the bearing.

[0226] Preferably, the center distance of the rolling elements 62 is 6.4 mm.

[0227] Preferably, two grooves are axially spaced apart on the inner circumference of the sleeve 60, the span of the grooves is consistent with the span L of the rolling body 62, and the two groups of rolling bodies 62 are respectively arranged in the grooves. The raceway of the rolling body 62 is directly opened on the sleeve 60, which can save the radial dimension occupied by the outer ring of the bearing assembly 6, so that the sleeve 60 has a larger thickness and improves the overall rigidity; or further reduce the outer diameter of the sleeve 60 to reduce the weight of the assembly.

[0228] Preferably, if Figure 2 As shown, the first outer ring 64 and the second outer ring 66 are fixedly arranged inside the two ends of the sleeve 60, and grooves are arranged on the inner circumferences of the first outer ring 64 and the second outer ring 66, respectively, and two groups of rolling bodies 62 are arranged in the grooves. The outer ring and the sleeve 60 of this structure are assembled, and the axial distance between the two outer rings can be adjusted to control the clearance and apply preload, which reduces the processing accuracy requirements of the sleeve 60.

[0229] Preferably, the rotating shaft 68 is a through shaft with a diameter of 5 mm, and a plurality of grooves are provided on the through shaft for mounting the rolling element 62 and accommodating the adhesive. The through shaft is easier to process than the stepped shaft, and has a higher processing accuracy than the stepped shaft. It can also avoid the local features such as the undercut groove brought by the stepped shaft that are prone to stress concentration, thereby improving the rigidity and strength of the shaft.

[0230] Optionally, the rolling element 62 and the shaft are both made of metal. The bearing assembly 6 made of metal can run stably at a working speed of 150,000 rpm, and is economical.

[0231] Optionally, the rotating shaft 68 is made of metal and the rolling element 62 is made of ceramic. The metal through shaft with a diameter of 5 mm has a certain rigidity and can be applied to the design requirements of most small high-speed fans; the bearing assembly 6 with ceramic balls can stably operate at a working speed of 160,000 rpm to 170,000 rpm, which can increase the limit speed and has a certain economy.

[0232] Preferably, the two groups of rolling elements 62 have the same number of rolling elements, which is 6 or 7.

[0233] In any of the above embodiments, preferably, the diffuser 2 further includes: a bearing seat 7, which is sleeved on the shaft sleeve 60 and accommodated in the first installation cavity 28, the bearing seat 7 is connected to the first protrusion 20, and at least a portion of the bearing seat 7 extends into the second installation cavity 100.

[0234] In this embodiment, the diffuser 2 further includes: a bearing seat 7, which is sleeved on the shaft sleeve 60 and accommodated in the first installation cavity 28. The bearing seat 7 is connected to the first protrusion 20, and at least a portion of the bearing seat 7 extends into the second installation cavity 100, thereby improving the efficiency of the fan.

[0235] In any of the above embodiments, preferably, a reinforcing rib 70 is provided between the bearing seat 7 and the inner ring arm 22 .

[0236] In this embodiment, a plurality of reinforcing ribs 70 are evenly distributed along the circumferential direction between the bearing seat 7 and the inner ring arm 22 to improve the reliability of the connection.

[0237] In any of the above embodiments, preferably, the first protrusion 20, the inner ring arm 22, the outer ring arm 24 and the bearing seat 7 are an integrated structure.

[0238] In this embodiment, the coaxiality of the impeller 1 and the wind shield 3 must be ensured by the dimension chain between the bearing assembly 6, the bearing seat 7, the first notch 240 of the diffuser 2 and the second notch 360 of the wind shield 3. The quality of the coaxiality will directly affect the uniformity of the tip clearance between the impeller 1 and the wind shield 3, thereby affecting the efficiency. The bearing seat 7 and the inner ring arm 22, the outer ring arm 24 and other features are integrally provided as the diffuser 2, so that the above-mentioned dimension chain can be concentrated on as few matching parts as possible, thereby ensuring assembly and high efficiency.

[0239] In any of the above embodiments, preferably, the rotor 8 includes: a magnetic ring 80 sleeved on the rotating shaft 68; and a protective sleeve 82 sleeved outside the magnetic ring 80; wherein a gap is provided between the magnetic ring 80 and the sleeve 60 along the axial direction of the rotating shaft 68.

[0240] like Figure 7As shown, in this embodiment, the rotor 8 includes a magnetic ring 80 formed in a ring shape, and a protective sleeve 82 fixedly sleeved on the outer circumferential surface of the magnetic ring 80. The magnetic ring 80 is fixedly connected to the shaft below the bearing assembly 6, and there is a gap between the magnetic ring 80 and the shaft sleeve 60 to prevent the rolling body 62 from being magnetized and affecting the service life.

[0241] In any of the above embodiments, preferably, the gap is greater than or equal to 3 mm.

[0242] In this embodiment, an axial distance of at least 3 mm is maintained between the end surface of the magnetic ring 80 and the end surface of the sleeve 60 to prevent the rolling element 62 from being magnetized, thereby affecting the life of the bearing assembly 6 .

[0243] Furthermore, if Figure 7 As shown, the protective cover 82 has an integrally formed reinforcement portion 820 and a balancing portion 822. Specifically, the reinforcement portion 820 is mainly arranged on the outer peripheral surface of the magnetic ring 80, has a thickness of 0.2mm to 0.3mm, and is fixed to the end face of the magnetic ring 80 through a spinning process to protect the magnetic ring 80 from disintegration during high-speed operation; the balancing portion 822 is arranged at the other end of the magnetic ring 80 away from the spinning part, has a thickness of about 1mm, and plays a role in balancing and deweighting. The integrated design of the protective cover 82 structure can reduce the number of parts, simplify the assembly process, and reduce costs.

[0244] Preferably, the balancing portion 822 is arranged on a side away from the sleeve 60, that is, the balancing portion 822 is arranged at the end of the rotor 8. The balancing portion 822 away from the center of gravity of the rotor 8 is convenient for deweighting, and the deweighting efficiency and reliability can be improved.

[0245] Preferably, the balancing portion 822 is arranged on a side close to the sleeve 60, that is, the balancing portion 822 is arranged between the bearing and the magnetic ring 80. The balancing portion 822 close to the center of gravity of the rotor 8 can shorten the axial length and make full use of the axial space.

[0246] Preferably, the protective cover 82 is made of non-magnetic conductive material.

[0247] In any of the above embodiments, preferably, the fan also includes: a frame 9, which is connected to the diffuser 2 and is arranged near the air outlet 32; the stator assembly 5 is connected to the bearing seat 7 through the frame 9, and a first flow path is provided between the stator assembly 5 and the frame 9, and a second flow path is provided between the stator assembly 5 and the rotor 8, and the first flow path and the second flow path are connected to the air duct.

[0248] like Fig.10As shown, in this embodiment, the stator assembly 5 is arranged on the radial outer side of the rotor 8 and is fixedly connected to the bearing seat 7 through the frame 9. The stator assembly 5 is fixedly arranged on the axial lower side of the diffuser 2, and at least part of the stator assembly 5 is located in the air duct to improve the heat dissipation effect of the stator assembly 5. At the same time, there is a first flow path between the stator assembly 5 and the frame 9, and a second flow path between the stator assembly 5 and the rotor 8. The first flow path and the second flow path are connected to the air duct to cool the heat-generating components on the flow path.

[0249] Specifically, Fig. 9 As shown, the stator assembly 5 includes an annular stator yoke 50 and a plurality of stator teeth 52 which are circumferentially spaced apart on the inner side of the stator yoke 50 and extend radially inward. The stator teeth 52 are formed as inner surfaces on the radial inner side, which are clearance-matched with the outer diameter of the rotor 8 and are axially arranged corresponding to the rotor 8. The stator assembly 5 also includes a winding 54 wound on the yoke, the maximum diameter of the winding 54 is smaller than the maximum diameter of the air duct, and the minimum diameter is larger than the inner surface of the stator teeth 52.

[0250] Furthermore, the frame 9 has an annular outer shell 90 axially arranged below the outer ring arm 24, and the outer shell 90 is provided with a stator mounting portion 16, which is fixed and accommodates the stator assembly 5 inwardly. A first flow path is formed between the inner wall of the outer shell 90 and the winding 54, which is used to lead the fluid in the air duct out of the fan and cool the stator components on the flow path. At the same time, the space between the stator and the rotor 8 forms a second flow path, which is connected to the air duct through the upper space of the stator assembly 5, and the fluid in the air duct is introduced between the stator assembly 5 and the rotor 8 to cool the heat-generating components on the flow path.

[0251] In any of the above embodiments, preferably, the fan further comprises: a control board 56 disposed at one end of the stator assembly 5 away from the diffuser 2, and at least a portion of the control board 56 is located in the first flow path and the second flow path.

[0252] like Fig.10 As shown, in this embodiment, the airflow in the air duct cools the stator assembly 5, the rotor 8 and the components on the electronic control board through the first flow path and the second flow path. At the same time, the first flow path and the second flow path are located below the air duct, that is, the high-speed gas is introduced into other heat-generating components for cooling only after the expansion is completed. Therefore, it will not affect the state of the airflow in the air duct, thereby ensuring efficiency while achieving a good heat dissipation design for the whole machine.

[0253] Specifically, a fan according to an embodiment of the present invention can efficiently operate within a speed range of 100,000 rpm to 150,000 rpm by adjusting input electrical parameters according to different design requirements without changing the overall structure of the fan.

[0254] By testing the fan using the above embodiment, the test results shown in Table 1 are obtained. It can be seen from the table that, in response to the design requirements of different power segments, the fan of this embodiment can adjust the speed through self-balancing and can operate efficiently in the speed range of 100000rpm to 150000rpm. At a high suction of 550W, it can stably operate at 150000rpm and obtain a whole machine efficiency higher than 52.5%, while covering down to 200W, the efficiency is higher than 54.5%.

[0255] Table 1

[0256]

[0257] According to a second aspect of the present invention, an electrical device (not shown in the figure) is also proposed, comprising: a fan as proposed in any embodiment of the first aspect.

[0258] The electrical equipment provided in the second aspect of the present invention comprises the fan provided in any one of the above embodiments and therefore has all the beneficial effects of the fan.

[0259] Specifically, the electrical appliance may be a vacuum cleaner or an air conditioner.

[0260] In the present invention, the term "plurality" refers to two or more than two, unless otherwise clearly defined. The terms "installed", "connected", "connected", "fixed", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; "connected" can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0261] In the description of this specification, the description of the terms "one embodiment", "some embodiments", "specific embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0262] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A fan, characterized in that: include: Drive structure; An impeller, the impeller comprising a cover plate, the cover plate being mounted on the driving structure, the cover plate being recessed toward the axial direction of the impeller, and the diameter of the cover plate gradually increasing along the air inlet direction; A wind cover, which is arranged on the impeller, and the wind cover is provided with an air inlet and an air outlet connected to the air inlet; A diffuser, the diffuser is located at one end of the impeller facing the air outlet, the diffuser includes a first convex portion connected to the driving structure, the first convex portion protrudes toward the wind cover, and the diameter of the end of the first convex portion close to the cover plate is smaller than the diameter of the end away from the cover plate, the diffuser also includes an inner ring arm connected to the first convex portion and an outer ring arm sleeved on the outer side of the inner ring arm, the outer ring arm is smoothly transitionally connected to the wind cover, and the first convex portion, the inner ring arm, and the outer ring arm are coaxially arranged; The wind hood, the cover plate and the diffuser define an air duct, and the air duct includes a variable cross-section portion and a constant cross-section portion, the variable cross-section portion is arranged close to the air inlet, and the constant cross-section portion is arranged close to the air outlet.

2. The fan according to claim 1, characterized in that: The driving structure comprises: The stator assembly is arranged relative to the air outlet so that the wind flow out of the air outlet blows directly toward the stator assembly.

3. The fan according to claim 2, characterized in that: An angle between an extension direction of one end of the cover plate toward the first protrusion and an extension direction of the first protrusion toward one end of the cover plate is less than or equal to a first threshold.

4. The fan according to claim 2, characterized in that: An annular recessed portion is disposed at one end of the first convex portion facing the air inlet, and an annular raised portion is disposed at one end of the cover plate facing the diffuser, and the recessed portion is clearance-matched with the raised portion.

5. The fan according to claim 2, characterized in that: The diameter of the connection between the first protrusion and the inner ring arm is the same as the diameter of the outer wall surface of the inner ring arm, and the connection is smoothly transitioned.

6. The fan according to claim 2, characterized in that: A first notch is provided on the side of the outer ring arm facing away from the axis of the drive structure, and a second notch matching the first notch is provided on the side of the wind shield facing the axis of the drive structure; The first notch and the second notch are both annular, and the side of the outer ring arm facing the air inlet abuts against the bottom of the second notch.

7. The fan according to any one of claims 1 to 6, characterized in that: The diffuser further comprises: A first blade is disposed between the inner ring arm and the outer ring arm, and two ends of the first blade along the radial direction of the diffuser are respectively attached to the inner ring arm and the outer ring arm, so that the first blade and the inner ring arm and the outer ring arm form an air guide cavity; The first blade is spiral-shaped, and includes an inlet end and an outlet end along the air inlet direction. Along the rotation direction of the impeller, the inlet end is located behind the outlet end.

8. The fan according to claim 7, characterized in that: The first blade is completely located in the wind cavity between the inner ring arm and the outer ring arm.

9. The fan according to claim 7, characterized in that: The angle between the extension direction of the inlet end and the radial direction of the inner ring arm is less than or equal to a second threshold; The outlet end includes a first inner end point connected to the inner ring arm and a first outer end point connected to the outer ring arm. Along the rotation direction of the impeller, the first inner end point is located in front of the first outer end point.

10. The fan according to claim 9, characterized in that: Along the axial direction of the diffuser, the inlet end is a smooth curved surface convex toward the impeller, and the outlet end is a smooth curved surface convex away from the impeller; Along the rotation direction of the impeller, of the two side surfaces of the first blade, the side surface located in the front is convex toward the rotation direction of the impeller, and the side surface located in the rear is concave toward the rotation direction of the impeller.

11. The fan according to claim 7, characterized in that: The inner ring arm, the first blade and the outer ring arm are an integrated structure; and / or There are multiple first blades, and the multiple first blades are evenly distributed between the inner ring arm and the outer ring arm along the circumferential direction of the inner ring arm.

12. The fan according to any one of claims 1 to 6, characterized in that: The impeller further comprises: a second blade, disposed on the cover plate, wherein the second blade is located in the air duct; Wherein, along the wind inlet direction, the second blade includes a leading edge close to the air inlet and a trailing edge close to the air outlet, and along the rotation direction of the impeller, the leading edge is located in front of the trailing edge.

13. The fan according to claim 12, characterized in that: The angle between the extension direction of the leading edge and the axial direction of the driving structure is within the range of 76°±2°; The trailing edge is located on the cylindrical surface formed by the outer side wall of the raised portion.

14. The fan according to claim 13, characterized in that: The leading edge includes a second inner end point connected to the cover plate and a second outer end point away from the cover plate, the second outer end point is located in front of the second inner end point along the rotation direction of the impeller, the second inner end point is located below the second outer end point from the air outlet to the air inlet, and the second outer end point is located at the end of the cover plate facing the air inlet and below the air inlet; The trailing edge includes a third inner endpoint connected to the cover plate and a third outer endpoint away from the cover plate, the third inner endpoint is located on the circumference of one end of the impeller facing the diffuser, and the third outer endpoint is located above the third inner endpoint in the direction from the air outlet to the air inlet.

15. The fan according to claim 14, characterized in that: In the projection of the impeller on a plane perpendicular to the axis of the drive structure, an angle between a line connecting the second inner end point and the axis of the drive structure and a line connecting the second outer end point and the axis of the drive structure is greater than or equal to 0° and less than or equal to 5°; and / or In the projection of the impeller on a plane perpendicular to the axis of the drive structure, an angle between a line connecting the third inner end point and the axis of the drive structure and a line connecting the third outer end point and the axis of the drive structure is greater than or equal to -2° and less than or equal to 2°; and / or The leading edge protrudes toward the air inlet, and the length of the trailing edge is smaller than the length of the leading edge.

16. The fan according to claim 12, characterized in that: A first gap is formed between an end of the second blade away from the axis of the impeller and the inner wall surface of the wind shield; Wherein, the first gap is equidistantly arranged in a direction from the air inlet to the air outlet, or the first gap gradually decreases in a direction from the air inlet to the air outlet.

17. The fan according to claim 16, characterized in that: The first gap is greater than or equal to 0.2 mm and less than or equal to 0.3 mm; and / or There are a plurality of second blades, and the plurality of second blades are evenly arranged on the cover plate along the circumferential direction of the cover plate.

18. The fan according to any one of claims 1 to 6, characterized in that: The inner wall surface of the wind shield includes a first inner wall surface corresponding to the cover plate and a second inner wall surface corresponding to the first convex portion, the first inner wall surface protrudes from the outer side of the wind shield toward the axial direction of the wind shield, and the second inner wall surface is concave from the axis of the wind shield toward the outer side of the wind shield, and the diameters of the first inner wall surface and the second inner wall surface gradually increase along the air inlet direction; The first inner wall surface, the second inner wall surface, the outer wall surface of the cover plate, the outer wall surface of the first protrusion, the outer wall surface of the inner ring arm, and the inner wall surface of the outer ring arm constitute the air duct.

19. The fan according to claim 18, characterized in that: The diameter of the connection between the second inner wall surface and the outer ring arm is the same as the diameter of the inner wall surface of the outer ring arm; Along the axial direction of the driving structure, a height difference between a connection point between the second inner wall surface and the outer ring arm, and a height difference between a connection point between the first protrusion and the inner ring arm is less than or equal to a third threshold.

20. The fan according to claim 18, characterized in that The wind shield also includes: A collecting surface, wherein the diameter of the collecting surface gradually decreases along the air inlet direction, the air inlet is located at one end of the collecting surface, and the other end of the collecting surface is smoothly transitionally connected to the first inner wall surface; Wherein, one end of the impeller facing the air inlet is located in the air cover.

21. The fan according to any one of claims 2 to 6, characterized in that: The driving structure also includes: A bearing assembly, the bearing assembly comprising a rotating shaft and a sleeve nested on the rotating shaft, and a plurality of rolling elements arranged between the sleeve and the rotating shaft, the impeller being fixedly arranged at one end of the rotating shaft; The rotor is fixedly arranged at the other end of the rotating shaft.

22. The fan according to claim 21, characterized in that The outer diameter of the sleeve is greater than or equal to 12 mm and less than or equal to 14 mm; The outer diameter of the matching area of ​​the rotating shaft and the shaft sleeve is greater than or equal to 4 mm and less than or equal to 6 mm.

23. The fan according to claim 21, characterized in that The cover plate and the first protrusion are thin-walled structures, the first protrusion defines a first installation cavity, the cover plate defines a second installation cavity, a mounting portion is provided in the second installation cavity, the mounting portion is sleeved on the rotating shaft, and the impeller is fixed on the rotating shaft through the mounting portion; Wherein, the rolling body close to the impeller is at least partially located in the second installation cavity.

24. The fan according to claim 23, characterized in that The diffuser further comprises: The bearing seat is sleeved on the shaft sleeve and accommodated in the first installation cavity. The bearing seat is connected to the first protrusion, and at least a part of the bearing seat extends into the second installation cavity.

25. The fan according to claim 24, characterized in that The first protrusion, the inner ring arm, the outer ring arm and the bearing seat are an integrated structure.

26. The fan according to claim 21, characterized in that The rotor comprises: A magnetic ring, sleeved on the rotating shaft; A protective sleeve, which is sleeved outside the magnetic ring; Wherein, there is a gap between the magnetic ring and the sleeve along the axial direction of the rotating shaft.

27. The fan according to claim 24, characterized in that Also includes: A frame is connected to the diffuser and is arranged near the air outlet. The stator assembly is connected to the bearing seat through the frame, and a first flow path is provided between the stator assembly and the frame, and a second flow path is provided between the stator assembly and the rotor. The first flow path and the second flow path are connected to the air duct.

28. The fan according to claim 27, characterized in that Also includes: A control plate is disposed at an end of the stator assembly away from the diffuser, and at least a portion of the control plate is located in the first flow path and the second flow path.

29. An electrical device, characterized in that: include: A fan as claimed in any one of claims 1 to 28.

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