Impeller, fan and cleaning device

Abstract

The application discloses a kind of impeller, fan and cleaning equipment, belong to fan technical field.The impeller includes hub and blade group;Blade group includes a plurality of main blades on the hub, a plurality of the main blade is arranged around the axis of the hub;Wherein, the tip line of the main blade and the root line are five-point fourth-order Bessel curve, the wrap angle θ1 of the tip line is 65~75 °, and the wrap angle θ2 of the root line is 75~85 °.The impeller, fan and cleaning equipment provided by the application, the blade type is constructed by high-order Bessel curve, compared with traditional circular arc or straight line, has higher degree of freedom and better curvature continuity, can realize the smooth transition and accurate type of blade surface in complex three-dimensional space, effectively suppresses the airflow separation of blade surface, improves aerodynamic efficiency and reduces noise.

Description

Technical Field

[0001] This application belongs to the field of wind turbine technology, specifically relating to an impeller, a wind turbine, and a cleaning device. Background Technology

[0002] As vacuum cleaners continue to evolve towards miniaturization, high power, and high efficiency, the performance requirements for the core power component—the brushless DC motor (BLDC motor)—are also increasing. To improve the overall suction power, current vacuum cleaners typically increase the impeller speed to boost output pneumatic power, thereby enhancing negative pressure capacity.

[0003] Currently, mainstream vacuum cleaners on the market, with a rated power of 800W or higher, typically require their BLDC brushless motors to drive the impeller at ultra-high speeds (such as 150,000 RPM or even higher). This ultra-high-speed operation directly challenges various key performance indicators of the motor. On the one hand, the high-speed rotating components inside the motor, such as bearings, rotor, and stator, experience significantly increased centrifugal stress and bear mechanical loads far exceeding those under normal operating conditions, leading to a shortened structural fatigue life and decreased product stability. On the other hand, high-speed operation inevitably brings about severe airflow disturbances and resonance problems, significantly increasing the noise level of the entire machine during operation, making it difficult to meet the quiet operation requirements of home use. Utility Model Content

[0004] The purpose of this application is to provide an impeller, a fan, and a cleaning device that can achieve high power density at low speeds while significantly reducing vibration and noise.

[0005] To achieve the above objectives, the technical solution provided in this application is as follows:

[0006] In a first aspect, this application provides an impeller comprising: a hub and a blade assembly; the blade assembly includes a plurality of main blades disposed on the hub, the plurality of main blades being arranged around the axis of the hub; wherein the tip profile and root profile of the main blades are both five-point fourth-order Bézier curves, the wrap angle θ1 of the tip profile is 65-75°, and the wrap angle θ2 of the root profile is 75-85°.

[0007] In one or more embodiments, the starting point P0 and ending point P4 of the five-point fourth-order Bézier curve corresponding to the tip profile of the main blade satisfy the following condition:

[0008] P0=(r0+H*tan(θ2 / 2),z0+H*sin(θ2 / 2)),

[0009] P4=(r0-H*tan(θ1 / 2),z0-H*sin(θ1 / 2));

[0010] Where r0 is the radial distance from the blade tip leading edge reference point to the impeller axis, z0 is the axial distance from the blade tip leading edge reference point to the impeller bottom surface, and H is the height of the main blade.

[0011] In one or more embodiments, the inlet airflow angle b1 of the tip meridional profile and the inlet airflow angle b2 of the root meridional profile of the main blade are 25-30°.

[0012] In one or more embodiments, the inlet airflow angle b1 of the blade tip meridional profile and the inlet airflow angle b2 of the blade root meridional profile satisfy the following conditions:

[0013]

[0014] f(θ1,H)=25+0.8θ1-0.05H,

[0015] K(t)=(1-t) 3 (3t 2 -2t+1);

[0016] Where t∈[0,1], H is the height of the main blade.

[0017] In one or more embodiments, the outlet airflow angle b3 of the tip meridional profile and the outlet airflow angle b4 of the root meridional profile of the main blade are 35-40°.

[0018] In one or more embodiments, the outlet airflow angle b3 of the blade tip meridional profile and the outlet airflow angle b4 of the blade root meridional profile satisfy the following conditions:

[0019]

[0020] g(θ2,H)=35+0.6θ1-0.1H;

[0021] Where, α i The leading edge local angle of attack of the main blade, p i H is the weighting coefficient, and H is the height of the main blade.

[0022] In one or more embodiments, the angle β between the trailing edge of the main blade and the tangent direction of the impeller circumference satisfies the following condition:

[0023]

[0024] Where η is the impeller aerodynamic efficiency under the current operating conditions, η max For the theoretical maximum efficiency, β opt is the optimal tangential angle, k1 and k2 are the efficiency decay factors when both sides deviate from the optimal tangential angle, m and n are nonlinear decay exponents, and e is the natural constant.

[0025] In one or more embodiments, the angle β between the trailing edge of the main blade and the tangent direction of the impeller circumference is 80-90°.

[0026] In one or more embodiments, the angle α between the leading edge of the main blade and the impeller axis is 75 to 90°.

[0027] In one or more embodiments, the height H of the main blade is 11 to 13 mm.

[0028] In one or more embodiments, the blade assembly further includes a plurality of diverter blades arranged around the axis of the hub, with one diverter blade between each pair of adjacent main blades.

[0029] In one or more embodiments, the splitter blade has a similar shape to the main blade, and the ratio of the height H of the main blade to the height h of the splitter blade is 1.2 to 1.3.

[0030] Secondly, this application provides a fan, which includes: a housing, a drive motor, a shroud, and an impeller as described above; the drive motor is disposed inside the housing, the impeller is disposed on the front side of the housing, the impeller is axially sleeved on the drive motor shaft around the drive motor shaft, and the shroud is disposed on the outside of the impeller and connected to the housing.

[0031] Thirdly, this application provides a cleaning device, which includes: a device body and a fan as described above, the fan being disposed on the device body.

[0032] The impeller, fan, and cleaning equipment provided in this application utilize high-order Bézier curves for blade profile construction. Compared to traditional circular or straight lines, this design offers greater freedom and superior curvature continuity, enabling smooth transitions and precise shaping of the blade surface in complex three-dimensional space. This effectively suppresses airflow separation on the blade surface, improves aerodynamic efficiency, and reduces noise. Different wrap angles are set at the blade tip and root, resulting in a gradual opening trend in the radial direction. This helps coordinate the airflow guidance behavior in different radius regions, thereby enhancing the momentum exchange capacity and pressure recovery effect of the flow field without relying on high rotational speeds, meeting the demands of high-load operation. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 This is a three-dimensional structural diagram of the impeller in one embodiment of this application;

[0035] Figure 2 for Figure 1 Top view of the impeller shown;

[0036] Figure 3 for Figure 1 Side view of the impeller shown;

[0037] Figure 4 for Figure 1 The main blades in the impeller are shown as a projection view in the impeller meridional plane;

[0038] Figure 5 This is a top view of the impeller in another embodiment of this application;

[0039] Figure 6 for Figure 5 Side view of the impeller shown;

[0040] Figure 7 This is a three-dimensional structural diagram of a fan in one embodiment of this application;

[0041] Figure 8 for Figure 7 The cross-sectional view of the fan shown.

[0042] Explanation of key figure labels:

[0043] 1-Impeller, 11-Hub, 12-Blade assembly, 121-Main blade, 122-Diverter blade, 2-Shell, 3-Drive motor, 31-Shaft, 4-Wind cover. Detailed Implementation

[0044] To enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of this application.

[0045] Unless otherwise expressly stated, throughout the specification and claims, the term "comprising" or its variations such as "including" or "comprises" shall be understood to include the stated elements or components without excluding other elements or other components.

[0046] With the widespread use of high-speed rotating cleaning equipment such as vacuum cleaners, users have placed higher demands on performance indicators such as overall suction power, compact size, operational stability, and service life. To meet these performance requirements, existing products generally adopt high-speed drive methods to increase output power and thus achieve higher suction power. However, after exceeding a certain power threshold, the negative impacts of high speed become increasingly apparent, especially in compact, small-sized motors. For example, increasing motor speed will cause internal components such as rotors and bearings to bear higher centrifugal loads, thereby accelerating fatigue wear, shortening lifespan, and accompanied by significant mechanical noise and aerodynamic disturbances.

[0047] Based on an analysis of the shortcomings of existing technologies, the inventors recognized that achieving high output performance without relying on ultra-high speeds hinges on fundamental impeller design. This involves altering the impeller's work on the airflow to improve its aerodynamic efficiency and load capacity at low to medium speeds. Therefore, this application proposes a novel impeller structure. Instead of relying on traditional two-dimensional blade profiles or simple geometric configurations to organize flow, it introduces a spatial modeling method with greater design freedom to construct a blade structure that is continuous, controllable, and three-dimensionally adaptable. Under this approach, the impeller blade profile can more accurately match the spatial evolution of the airflow path, optimizing the aerodynamic work path and achieving high-efficiency operation at low speeds. This ensures structural compactness while effectively controlling noise, extending service life, and increasing power density.

[0048] Please refer to Figure 1 , Figure 2 and Figure 3 As shown, in one embodiment of this application, the impeller 1 includes a hub 11 and a blade assembly 12. The blade assembly 12 includes a plurality of main blades 121 disposed on the hub 11, and the plurality of main blades 121 are arranged around the axis of the hub 11. The tip profile L1 and root profile L2 of the main blades 121 are both five-point fourth-order Bezier curves. The wrap angle θ1 of the tip profile L1 is preferably 65–75°, and the wrap angle θ2 of the root profile L2 is preferably 75–85°.

[0049] The hub 11, as the central support structure of the entire impeller 1, functions to provide a reference surface for blade installation and to form a connecting bridge between the impeller 1 and the motor shaft 31, transmitting rotational power to the entire impeller 1 system. It guides airflow into the impeller 1 and achieves energy conversion through the rotation of the blades. The hub 11 has a tapered frustum-shaped structure.

[0050] The multiple main blades 121 arranged around the hub 11 are the core components for the impeller 1 of this invention to perform work. Each main blade 121 is structurally distributed evenly along the circumference with the hub 11 as the base point and has a certain helical angle. This helical arrangement enables the blades to generate effective axial and centrifugal guiding effects when rotating, guiding the intake airflow from the axial direction into a radial or mixed flow form with a certain momentum and pressure, thereby achieving suction output.

[0051] The airfoil structure of each main blade 121 is a spatial design, meaning that the root profile L2 near the hub 11 and the tip profile L1 near the outer edge are both five-point fourth-order Bézier curves. The airfoil structure of the main blade 121 is formed through spatial twisting fitting. The Bézier curves are parametrically controlled by the starting point, three intermediate control points, and the ending point to form a smooth and continuous curve profile. The aforementioned five-point fourth-order Bézier curves satisfy the following equation:

[0052] B(t)=P0(1-t) 4 +4P1t(1-t) 3 +6P2t 2 (1-t)+4P3t 3 (1-t)+P4t 4 , t∈(0~1);

[0053] Where B(t) is the coordinate of the point at time t, with P0 as the starting point, P4 as the ending point, and P1, P2, and P3 as control points in the same plane.

[0054] Compared with traditional two-dimensional or low-order blade profiles, the five-point fourth-order Bézier curve has a higher degree of freedom in shape and better curvature continuity. It can precisely control the changing trend of the blade surface in three-dimensional space, making the blade profile more closely fit the airflow path. It can effectively reduce abrupt changes and separation of airflow on the blade surface, thereby significantly improving aerodynamic efficiency and reducing flow separation and energy loss.

[0055] The wrap angle (θ) describes the degree of blade profile opening, defining the angular range of the blade from the leading edge L3 to the trailing edge L4 around the central axis of impeller 1. It represents the radial and axial deflection angles from the leading edge L3 to the trailing edge L4, determining the relative flow path length and direction change of the airflow passing through the blade. During impeller 1 operation, the airflow enters from the leading edge L3, undergoing velocity and pressure changes on the blade surface. If the wrap angle is set appropriately, the airflow can smoothly adhere to the blade surface, forming an effective conversion process from kinetic energy to pressure energy. However, if the wrap angle is inappropriate, it can lead to unstable phenomena such as flow separation, vortices, and secondary flow, reducing aerodynamic efficiency and increasing noise.

[0056] The blade tip profile L1 is located in the outer edge region of impeller 1, where the airflow velocity is high and the centrifugal force is significant. When impeller 1 rotates, the aerodynamic load on the blade tip region is much greater than that on the blade root region due to centrifugal force. Simultaneously, in mixed-flow or centrifugal impeller 1, the airflow is more prone to abrupt velocity changes or separation near the blade tip. Therefore, a gentler blade profile with a smaller opening angle is needed in the blade tip region to guide the airflow smoothly, maintain adhesion, and prevent efficiency loss and increased noise. Setting θ1 in the range of 65–75° achieves optimal tangential acceleration and pressure rise in high-speed airflow. The smaller wrap angle makes the blade profile at the blade tip more compact, and the airflow is moderately guided by bending, avoiding excessive flow resistance.

[0057] If the wrap angle θ1 of the blade tip profile L1 is less than 65°, the blade will not open sufficiently in the tip region, easily resulting in an excessively short force-bearing area. This leads to insufficient guiding ability of the blade at the outer edge, reduced tangential velocity variation, and decreased working efficiency of impeller 1. Furthermore, the excessively short blade may increase the risk of flow separation, resulting in vortex losses. If θ1 is greater than 75°, the blade will bend excessively at the outer edge, causing excessive resistance to the airflow. This may trigger local pressure surges and turbulence, reducing efficiency and increasing noise.

[0058] The blade root profile L2 is close to the hub 11, where the airflow velocity is relatively low. The flow path is significantly affected by the boundary layer of the hub 11. Due to its proximity to the hub 11, low radial velocity, and relatively stable flow, the wrap angle can be moderately increased to enhance guiding capability and the structural support surface of the blade, thereby improving work capacity. Therefore, θ2 is set to 75–85°, slightly larger than the blade tip wrap angle. This design increases the guiding length of the airflow at the blade root, effectively improving the pressure recovery capability of low-speed airflow and balancing the overall flow field distribution of the impeller 1.

[0059] If the wrap angle θ2 of the blade root profile L2 is less than 75°, the guiding length for low-speed airflow at the blade root is insufficient, the pressure recovery capability near the hub 11 decreases, resulting in an uneven flow field and affecting overall performance. If θ2 exceeds 85°, excessive bending of the blade at the hub 11 may exacerbate boundary layer separation, forming secondary flow, which not only reduces efficiency but may also increase vibration and noise due to turbulent flow field.

[0060] In one exemplary embodiment, please refer to Figure 1 , Figure 2 and Figure 3 As shown, the starting point P0 and ending point P4 of the five-point fourth-order Bézier curve corresponding to the tip profile L1 of the main blade 121 satisfy the following conditions:

[0061] P0=(r0+H*tan(θ2 / 2),z0+H*sin(θ2 / 2)),

[0062] P4=(r0-H*tan(θ1 / 2),z0-H*sin(θ1 / 2));

[0063] Where r0 is the radial distance from the blade tip leading edge L3 reference point to the axis of impeller 1, z0 is the axial distance from the blade tip leading edge L3 reference point to the bottom surface of impeller 1, and H is the height of the main blade 121.

[0064] The Bézier curve is determined by five control points (P0 to P4), where P0 and P4 are boundary points whose positions play a decisive role in the overall direction, opening, and twisting tendency of the curve. By formulaically constructing the coordinate positions of P0 and P4, the wrap angle design concept can be embedded into the blade shape generation algorithm. Through the geometric constraints of the wrap angle, the airflow guidance capability of the blade tip and blade root can be coordinated.

[0065] In one exemplary embodiment, please refer to Figure 4 As shown, the inlet airflow angle b1 of the blade tip meridional profile and the inlet airflow angle b2 of the blade root meridional profile of the main blade 121 are preferably 25-30°, where l1 is the projection of the blade tip profile L1 onto the meridional plane of the impeller 1, and l2 is the projection of the blade root profile L2 onto the meridional plane of the impeller 1. The meridional profile inlet airflow angle defines the deflection angle of the airflow at the impeller 1 inlet relative to the meridional plane (the radial plane including the axis of the impeller 1). The inlet airflow angle directly determines the initial direction of the airflow when it enters the impeller 1, affecting the blade's angle of attack, the smoothness of the airflow, and the overall energy conversion efficiency.

[0066] Before entering the blade, the airflow impacts the leading edge L3 of the blade at a certain angle; this angle is known as the inlet airflow angle. From the meridional plane, the inlet airflow angle determines the angle between the fluid velocity vector and the blade surface. Essentially, it determines whether the incoming flow can form a small relative angle of attack with the blade surface direction to achieve good adhesion and energy exchange.

[0067] If the inlet angle is set properly, the airflow can enter the blade passage in a near-tangential manner, adhere along the leading edge L3 of the blade, and obtain velocity conversion and pressure boost on the surface of the blade, avoiding flow separation. Conversely, if the angle between the airflow direction and the blade surface is too large (i.e., the angle of attack is too large), it is easy to cause incoming flow impact, adhesion damage or even stall, which in turn induces vortices in the flow passage, reduces efficiency and increases noise.

[0068] In the impeller 1 structure of this embodiment, a Bézier curve airfoil with a large spatial twist is adopted, especially in the blade tip and blade root regions where independent profiles are constructed to match the velocity distribution. When the inlet airflow angle on the meridional plane is controlled at 25-30°, better flow adhesion and blade surface pressure distribution can be achieved, ensuring that separation does not occur in the inlet region and that the pressure gradient is gentle, which is conducive to the smooth transition of high-speed airflow.

[0069] Specifically, the inlet airflow angle b1 of the blade tip meridional profile and the inlet airflow angle b2 of the blade root meridional profile satisfy the following conditions:

[0070]

[0071] f(θ1,H)=25+0.8θ1-0.05H,

[0072] K(t)=(1-t) 3 (3t 2 -2t+1);

[0073] Where t∈[0,1], H is the height of the main blade 121.

[0074] In one exemplary embodiment, please refer to Figure 4 As shown, the outlet airflow angle b3 of the tip meridional profile of the main blade 121 and the outlet airflow angle b4 of the root meridional profile are preferably 35-40°. The outlet airflow angle of the meridional profile refers to the angle at which the airflow leaves the blade at the blade outlet along the meridional direction (i.e., the plane formed by the axial and radial directions). This angle not only determines the direction of the airflow after leaving the blade, but also directly affects the matching degree between the impeller 1 and the downstream guide system (such as the diffuser or volute).

[0075] From the perspective of momentum conservation, the core function of impeller 1 is to transfer the mechanical energy generated by rotational motion to the gas, enabling it to gain velocity increments and pressure increases as it passes through the blades. During this process, the outlet angle of the airflow determines the energy distribution ratio (kinetic energy to static pressure) and the degree of expansion and diffusion efficiency of the airflow in the diffuser section. A reasonable outlet angle ensures a smooth airflow transition, minimizing energy loss and disturbance; conversely, an inappropriate angle may result in backflow, separation, or shock waves, reducing aerodynamic efficiency.

[0076] The impeller 1 in this embodiment is a semi-open mixed-flow structure, exhibiting both centrifugal and axial components in its flow characteristics. In this type of flow field, the airflow needs to possess a certain axial component upon exiting the blades to achieve an effective transition, while retaining sufficient radial momentum to provide the necessary suction and pressure difference. When the outlet airflow angle is 35–40°, the outlet airflow can smoothly follow the meridional plane away, reducing boundary layer separation and vortex generation, and enhancing the centrifugal effect at lower speeds through appropriate airflow deflection.

[0077] Specifically, the outlet airflow angle b3 of the blade tip meridional profile and the outlet airflow angle b4 of the blade root meridional profile satisfy the following conditions:

[0078]

[0079] g(θ2,H)=35+0.6θ1-0.1H;

[0080] Where, αi The main blade 121 leading edge L3 local angle of attack, p i H is the weighting coefficient, and H is the height of the main blade 121.

[0081] In one exemplary embodiment, please refer to Figure 3 As shown, the angle β (tangential angle) between the trailing edge L4 of the main blade 121 and the circumferential tangent of the impeller 1 is preferably 80–90°. When the impeller 1 is operating, the airflow accelerates after passing the leading edge L3 and the middle section of the blade, eventually reaching the trailing edge L4. In this region, the airflow needs to exit along the trailing edge L4, rapidly adjusting its direction to meet the requirements of centrifugal or axial diffusion. The angle β between the trailing edge L4 and the circumferential tangent is the parameter that determines this exit process. The angle β can be determined using the following formula:

[0082]

[0083] Where η is the aerodynamic efficiency of impeller 1 under the current operating conditions, η max For the theoretical maximum efficiency (determined by the smoothness of the blade shape), β opt is the optimal tangential angle obtained from experiments or simulations, k1 and k2 are the efficiency decay factors when both sides deviate from the optimal tangential angle, m and n are the nonlinear decay exponents (m = n, controlling the rate of increase of efficiency loss), and e is the natural constant.

[0084] When β is in the range of 80° to 90°, the airflow along the blade trailing edge L4 can form a relatively ideal separation angle, allowing the airflow to maintain high adhesion and minimizing local flow separation or instability, thus achieving smooth airflow separation. This smooth flow reduces turbulence and vortex formation in the flow field, reduces energy loss, and thus improves aerodynamic efficiency. Within this range, the aerodynamic characteristics reach a better balance, ensuring sufficient centrifugal force to effectively remove the airflow without causing unnecessary energy dissipation due to excessive separation.

[0085] The setting of the trailing edge angle L4 β is also directly related to the overall energy conversion and pressure recovery process of impeller 1. If β is set outside the range of 80° to 90°, it may cause a series of problems. When β is less than 80°, the deviation angle of the blade trailing edge L4 relative to the circumferential tangent is too small, and the airflow may not be able to achieve sufficient deflection when leaving the blade. As a result, the kinetic energy of the airflow cannot be fully converted into static pressure, that is, the aerodynamic work efficiency is reduced; at the same time, under this condition, the airflow is prone to premature separation, forming local eddies and turbulence, aggravating flow noise and pressure fluctuations, thereby affecting the overall working stability of the impeller, and may have adverse effects on downstream devices (such as diffusers or volutes).

[0086] On the other hand, if β is greater than 90°, the airflow will be excessively deflected when leaving the blade trailing edge L4, meaning the angle between the airflow direction and the tangent of the impeller 1 circumference exceeds 90°. This usually leads to backflow or reverse impact, resulting in an extremely unstable flow state. Backflow not only causes local pressure anomalies but also increases aerodynamic drag and reduces the effective energy transferred to the downstream system. Furthermore, the reverse impact can induce shock waves or strong local vortices, significantly increasing aerodynamic noise.

[0087] In one exemplary embodiment, please refer to Figure 3 As shown, the angle α between the leading edge L3 of the main blade 121 and the axial direction of the impeller 1 is 75-90°. The angle α describes the degree of deflection of the blade leading edge L3 relative to the rotation axis 31 of the impeller 1 (i.e., the axial direction), and its design is related to the incident direction of the incoming flow, angle of attack control, flow adhesion, and the overall working efficiency of the impeller 1.

[0088] During the operation of impeller 1, the airflow typically enters the inlet region of impeller 1 in an axial or near-axial direction, and the leading edge L3 angle α of the main blade 121 determines the angle of attack of the blade surface relative to the inflow. The larger the angle α, the more upright the blade leading edge L3 is to the axial airflow direction, meaning the blade is closer to being parallel to the radial surface; conversely, the smaller α, the closer the blade is to the airflow direction.

[0089] Setting the included angle α within the range of 75° to 90° optimizes the matching between the airflow and the blade leading edge L3. This range allows the airflow to enter the blade at a near-vertical or slightly inclined angle (90° being completely perpendicular to the axial direction), maximizing the initial increment of tangential velocity and laying the foundation for subsequent airflow acceleration and pressure rise. At the same time, a range slightly less than 90° (such as 75°) allows for a certain degree of axial component, reducing flow resistance at the inlet and ensuring smooth airflow into the blade passage.

[0090] If the included angle α is less than 75°, the airflow is too biased towards the axial direction, reducing the angle of attack of the blade leading edge L3 and resulting in insufficient initial increment of the tangential velocity component, thus decreasing the initial work capacity of impeller 1. If the included angle α is greater than 90°, the airflow is too biased towards the radial direction or even tilted in the opposite direction (beyond the vertical direction), increasing the resistance of the inlet channel and exacerbating the pressure loss when the airflow enters the blade. This situation may generate a local high-pressure zone at the blade leading edge L3, inducing turbulence and boundary layer separation, which not only reduces aerodynamic efficiency but may also exacerbate vibration and noise due to flow field turbulence.

[0091] In one exemplary embodiment, please refer to Figure 3As shown, the height H of the main blade 121 is 11–13 mm. The blade height directly determines the cross-sectional area and flow path of the airflow channel. When the height H of the main blade 121 is within the range of 11–13 mm, it ensures both sufficient airflow and good adhesion of the airflow to the blade surface, thereby making the conversion of aerodynamic energy more efficient.

[0092] The blade height determines the stress-bearing area and the distribution of aerodynamic loads. Setting it within the range of 11–13 mm can ensure blade strength and stiffness while reasonably distributing centrifugal force and aerodynamic loads, preventing stress concentration, and extending blade life.

[0093] If the blade height H is less than 11mm, the blade's stress-bearing area is too small, which may lead to local stress concentration, exacerbate local fatigue, and thus shorten its service life. When the height H exceeds 13mm, although the blade increases the airflow channel, it also brings greater bending force and centrifugal load. Especially under high load, this will cause uneven stress on the blade, which may lead to structural deformation or even damage, affecting stable operation.

[0094] In one exemplary embodiment, please refer to Figure 5 and Figure 6 As shown, the blade assembly 12 also includes multiple splitter blades 122 arranged around the axis of the hub 11. A splitter blade 122 is provided between every two adjacent main blades 121, thus forming a composite blade assembly 12 structure in which the main blades 121 and the splitter blades 122 are arranged alternately. This design enriches the flow channel configuration of the impeller 1 and can improve the continuity of airflow guidance and the stability of the overall flow field.

[0095] Specifically, all blades are arranged spirally along the axis of the hub 11, with the main blade 121 being the core working blade, responsible for converting the mechanical energy output by the motor into kinetic and pressure energy of the air to generate suction. The diverter blades 122 added between every two main blades 121 act as auxiliary guide components, typically lower in height and size than the main blades 121. This alternating high and low, main and auxiliary arrangement effectively guides the airflow more smoothly between the main blades 121 without significantly increasing the overall impeller resistance.

[0096] The placement of the splitter blades 122 helps improve the local flow structure within the channels between the main blades 121. Because there is a certain flow channel space between the main blades 121, under high speed and heavy load conditions, turbulence, secondary flow, or vortex phenomena easily occur in these areas, leading to increased energy loss and noise. The splitter blades 122 create additional guiding surfaces between the main blades 121, effectively refining and distributing the larger flow channels, allowing the airflow to pass more smoothly along the spiral direction through the entire impeller 1, thereby improving overall aerodynamic efficiency and reducing noise caused by flow disturbances.

[0097] Specifically, please refer to Figure 5 and Figure 6 As shown, the splitter blade 122 is similar in shape to the main blade 121, and the ratio of the height H of the main blade 121 to the height h of the splitter blade 122 is 1.2 to 1.3. The main blade 121 and the splitter blade 122 not only form an alternating layout in terms of arrangement, but also maintain similarity in geometric shape, thus constructing a composite blade system with continuous structure and complementary functions.

[0098] Specifically, the shape of the splitter blade 122 can be considered a scaled-down version of the main blade 121. Its profile, surface curvature, and spatial twist direction are basically the same as the main blade 121, which can be understood as a proportional scaling down in size. In aerodynamic design, the main blade 121 undertakes the primary function of kinetic energy to pressure energy conversion. Its relatively large height is designed to create sufficient pressure differential and provide strong suction output. Although the splitter blade 122 does not directly undertake the main task in energy conversion, its scaled-down geometric features allow it to act as an airflow guide between the main blades 121. In complex flow conditions, it helps to rectify and stabilize the flow field, reducing vortices, secondary flows, and flow separation phenomena caused by the large blade spacing. The ratio of the height H of the main blade 121 to the height h of the splitter blade 122 can be determined by the following formula:

[0099]

[0100] η is the aerodynamic efficiency of impeller 1 under the current operating conditions. max For theoretical maximum efficiency, H avg 122 is the average height of the main blade and the shunting blade, and c1 and c2 are empirical coefficients for the efficiency degradation due to the height difference between the main blade and the shunting blade.

[0101] When the ratio of the blade height H to the height h of the splitter blade 122 is 1.2 to 1.3, it represents the optimal range for balancing airflow disturbance control and flow channel unobstructedness. If the height of the splitter blade 122 is too small, its guiding capacity will be insufficient, and it will be unable to effectively suppress flow field instability. Conversely, if its height is close to that of the main blade 121, it may cause excessive flow channel contraction, increased drag, and weaken the dominant role of the main blade 121 in the airflow.

[0102] Please refer to Figure 7 and Figure 8 As shown, this application also relates to a fan, which includes: a housing 2, a drive motor 3, a fan cover 4, and the aforementioned impeller 1; the drive motor 3 is disposed inside the housing 2, the impeller 1 is disposed on the front side of the housing 2, the impeller 1 is axially sleeved on the drive motor 3's rotating shaft 31, and the fan cover 4 is disposed on the outside of the impeller 1 and connected to the housing 2.

[0103] The housing 2, serving as the main frame of the fan, is preferably made of a robust and durable material and has a cylindrical or slightly tapered shape. Its internal space can accommodate the drive motor 3. The housing 2 has a front opening, providing space for the installation of the impeller 1 and the formation of the airflow channel.

[0104] The drive motor 3 is installed inside the housing 2, and its shaft 31 extends forward axially, passing through the front opening of the housing 2, serving as the core of the system's power output. The impeller 1, as the core aerodynamic component of the fan, is located on the front side of the housing 2. The center hole of its hub 11 is tightly connected to the shaft 31 of the drive motor 3 via an axial sleeve connection. The sleeve connection can employ a keyway or tight-fitting process to ensure that the impeller 1 is firmly fixed to the shaft 31 and maintains concentricity and stability during high-speed rotation. The main blades 121 and the branch blades 122 of the impeller 1 are spirally arranged around the axis of the hub 11, opening forward to form the intake and exhaust channels for airflow.

[0105] The shroud 4 covers the outside of the impeller 1 in a shroud-like structure. It can be connected to the front edge of the casing 2 by bolts, clips, or other means to form an airflow guiding space. The shroud 4 has a streamlined shape that gradually tapers forward, maintaining an appropriate gap with the outer edge of the impeller 1, which both protects the impeller 1 and guides the airflow to be discharged smoothly.

[0106] In addition, this application also relates to a cleaning device, which may be a sweeper, a vacuum cleaner, etc. The cleaning device includes a main body and the aforementioned fan, with the fan mounted on the main body to provide suction for the cleaning device.

[0107] In summary, the impeller, fan, and cleaning equipment provided in this application utilize high-order Bézier curves for blade profile construction. Compared to traditional circular or straight lines, this design offers greater freedom and superior curvature continuity, enabling smooth transitions and precise shaping of the blade surface in complex three-dimensional space. This effectively suppresses airflow separation on the blade surface, improves aerodynamic efficiency, and reduces noise. The different wrap angles at the blade tip and root create a gradual opening trend in the radial direction, facilitating the coordination of airflow guidance behavior in different radius regions. This enhances the momentum exchange capacity and pressure recovery effect of the flow field without relying on high rotational speeds, meeting the demands of high-load operation.

[0108] It will be apparent to those skilled in the art that this application is not limited to the details of the exemplary embodiments described above, and that this application can be implemented in other specific forms without departing from the spirit or essential characteristics of this application. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this application is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within this application. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0109] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. An impeller, characterized in that, include: Wheel hub; The blade assembly includes multiple main blades disposed on the hub, and the multiple main blades are arranged around the axis of the hub; The tip and root profiles of the main blades are both five-point fourth-order Bezier curves. The wrap angle θ1 of the tip profile is 65-75°, and the wrap angle θ2 of the root profile is 75-85°.

2. The impeller according to claim 1, characterized in that, The starting point P0 and ending point P4 of the five-point fourth-order Bézier curve corresponding to the tip profile of the main blade satisfy the following conditions: P0=(r0+H*tan(θ2 / 2),z0+H*sin(θ2 / 2)), P4=(r0-H*tan(θ1 / 2),z0-H*sin(θ1 / 2)); Where r0 is the radial distance from the blade tip leading edge reference point to the impeller axis, z0 is the axial distance from the blade tip leading edge reference point to the impeller bottom surface, and H is the height of the main blade.

3. The impeller according to claim 1, characterized in that, The inlet airflow angle b1 of the blade tip meridional profile and the inlet airflow angle b2 of the blade root meridional profile satisfy the following conditions: f(θ1,H)=25+0.8θ1-0.05H, K(t)=(1-t) 3 (3t 2 -2t+1); Where t∈[0,1], H is the height of the main blade.

4. The impeller according to claim 1, characterized in that, The inlet airflow angle b1 of the tip meridian profile and the inlet airflow angle b2 of the root meridian profile of the main blade are 25-30°.

5. The impeller according to claim 1, characterized in that, The outlet airflow angle b3 of the blade tip meridional profile and the outlet airflow angle b4 of the blade root meridional profile satisfy the following conditions: g(θ2,H)=35+0.6θ1-0.1H; Where, α i The leading edge local angle of attack of the main blade, p i H is the weighting coefficient, and H is the height of the main blade.

6. The impeller according to claim 1, characterized in that, The airflow angle b3 at the tip of the main blade and the airflow angle b4 at the root of the main blade are 35-40°.

7. The impeller according to claim 1, characterized in that, The angle β between the trailing edge of the main blade and the tangent direction of the impeller circumference is determined according to the following formula: Where η is the impeller aerodynamic efficiency under the current operating conditions, η max For the theoretical maximum efficiency, β opt is the optimal tangential angle, k1 and k2 are the efficiency decay factors when both sides deviate from the optimal tangential angle, m and n are nonlinear decay exponents, and e is the natural constant.

8. The impeller according to claim 1, characterized in that, The angle β between the trailing edge of the main blade and the tangent direction of the impeller circumference is 80-90°.

9. The impeller according to claim 1, characterized in that, The angle α between the leading edge of the main blade and the impeller axis is 75-90°.

10. The impeller according to claim 1, characterized in that, The height H of the main blade is 11-13 mm.

11. The impeller according to claim 1, characterized in that, The blade assembly also includes multiple diverter blades arranged around the axis of the hub, with one diverter blade between each pair of adjacent main blades.

12. The impeller according to claim 11, characterized in that, The splitter blade has a similar shape to the main blade, and the ratio of the height H of the main blade to the height h of the splitter blade is 1.2 to 1.

3.

13. A fan, characterized in that, include: The device comprises a housing, a drive motor, a fan shroud, and an impeller as described in any one of claims 1 to 12; the drive motor is disposed inside the housing, the impeller is disposed on the front side of the housing, the impeller is axially sleeved on the drive motor shaft around the drive motor shaft, and the fan shroud is disposed on the outside of the impeller and connected to the housing.

14. A cleaning device, characterized in that, include: The equipment body and the fan as described in claim 13, wherein the fan is mounted on the equipment body.

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