Fan and electric equipment

Abstract

The invention provides a fan and electric equipment, and belongs to the field of fans. The fan comprises a centrifugal impeller, an air inlet cover, an axial flow impeller and a fluid director. The air inlet cover is arranged on the outer side of the centrifugal impeller in a covering mode and provided with an air inlet located in the upstream of the centrifugal impeller and an air channel communicated with the air inlet and used for guiding airflow to be exhausted in the axial direction of the draught fan. The axial flow impeller is arranged at the downstream of the air duct and is used for doing work on air flow exhausted by the air duct; the fluid director is arranged on the downstream portion of the axial flow impeller and used for guiding airflow exhausted from the axial flow impeller to flow in the axial direction of the draught fan. Compared with a single-stage acting structure, the fan and the electric equipment provided by the invention are more beneficial to improving the overall pressure rise and suction capacity and reducing noise, so that airflow is stably output in the axial direction, and the quality of an airflow outlet flow field and the energy utilization efficiency are improved.

Description

Fans and electrical equipment Technical Field

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

[0002] Vacuum cleaners, electric suction devices, and other small airflow generating equipment typically rely on a motor to drive an impeller to rotate, creating negative pressure within the flow channel to suction air and particulate matter. In existing technologies, a common approach is to use a single-stage centrifugal impeller as the core working component. This impeller's rotation applies centrifugal force to the airflow, increasing its velocity and pressure to achieve the required suction capacity.

[0003] However, as related products continue to develop towards higher suction power, miniaturization, and lighter weight, the single-stage centrifugal impeller solution has gradually revealed its significant limitations. The pressure rise achievable by a single-stage centrifugal impeller under finite size conditions has a certain upper limit. When the impeller load continues to increase, it easily leads to airflow turbulence, increased local energy loss, and decreased operating efficiency, thus limiting further improvements in the overall suction power of the machine. Summary of the Invention

[0004] Given the limited external dimensions of the fan, especially the internal installation space, it is usually necessary to increase the input power, increase the blade load, or increase the impeller speed to further improve the suction capacity. However, the above methods often lead to increased noise and vibration of the whole machine, and subject the impeller and related support structures to higher centrifugal loads and fatigue stresses, which adversely affect the acoustic performance, mechanical reliability and service life.

[0005] The airflow discharged from a centrifugal impeller typically has a large circumferential velocity component and high kinetic energy. If this airflow is not properly guided and adjusted, it can easily lead to significant swirling, uneven velocity distribution, and insufficient pressure recovery in the downstream flow channel. This not only reduces the effective utilization rate of airflow energy but may also affect the stable axial output of the airflow. For products like vacuum cleaners that require both high suction power and a compact internal structure, relying solely on a single-stage centrifugal power structure often makes it difficult to simultaneously meet the demands for high pressure rise, low noise, stable flow, and a small footprint.

[0006] In view of the aforementioned technical problems, the purpose of this disclosure is to provide a fan and electric equipment that can achieve a high overall pressure rise within a limited axial dimension, and is conducive to improving energy conversion efficiency and reducing noise level.

[0007] To achieve the above objectives, the technical solution provided in this disclosure is as follows:

[0008] In a first aspect, this disclosure provides a fan comprising a centrifugal impeller, an air inlet shroud, an axial flow impeller, and a guide vane. The air inlet shroud is disposed outside the centrifugal impeller and has an air inlet located upstream of the centrifugal impeller, and an air duct connecting to the air inlet and used to guide airflow outwards along the axial direction of the fan. The axial flow impeller is disposed downstream of the air duct and used to perform work on the airflow discharged from the air duct. The guide vane is disposed downstream of the axial flow impeller and used to guide the airflow discharged from the axial flow impeller to flow along the axial direction of the fan. By arranging the centrifugal impeller, air inlet shroud, axial flow impeller, and guide vane sequentially, the airflow undergoes a process of pre-stage pressurization, subsequent stage work, and downstream guiding and rectification within the fan, thereby improving the overall pressure rise and suction capacity under a more compact structural condition, and enhancing the stability of the airflow output.

[0009] In one or more embodiments, the centrifugal impeller includes a conical portion disposed within the air duct along the axial direction of the fan, the outer diameter of the conical portion gradually decreasing in the direction pointing towards the air inlet. By providing a conical portion in the centrifugal impeller, and the outer diameter of the conical portion gradually decreasing in the direction pointing towards the air inlet, it is beneficial to improve the introduction state of the airflow when entering the centrifugal impeller, reduce the flow loss caused by abrupt changes in airflow, and thereby improve the flow smoothness at the inlet of the centrifugal impeller.

[0010] In one or more embodiments, the centrifugal impeller includes a plurality of first blades arranged around the axis of the cone, the plurality of first blades being spaced apart on the outer peripheral surface of the cone; the first blades extend at least partially along the axial and circumferential directions of the cone in a spiral manner, such that a compression channel with an axial extension component is formed between two adjacent first blades. By arranging a plurality of first blades around the axis of the cone and extending at least partially along the axial and circumferential directions of the cone in a spiral manner to form a compression channel with an axial extension component, it is beneficial to achieve centrifugal pressurization while also considering the downstream transition of the airflow, thereby improving the upstream work efficiency and flow quality.

[0011] In one or more embodiments, the compression channel is provided with a second blade for flow diversion, the second blade extending from the middle region of the compression channel to the outlet end of the compression channel. By providing a second blade for flow diversion in the compression channel, it is beneficial to further guide and distribute the airflow inside the compression channel, improve the stability of the local flow field, and make the airflow smoother when flowing towards the outlet end, thereby reducing turbulence and local losses.

[0012] In one or more embodiments, the air duct includes an inlet section and an outlet section. The wall profile of the inlet section is adapted to the outer edge of a plurality of first blades. The outlet section surrounds the outer periphery of the outlet end of the compression flow channel and has a guide surface for guiding airflow outward along the axial direction of the fan. By adapting the inlet section of the air duct to the outer edge of the first blades and the guide surface of the outlet section, it is beneficial to optimize the air intake organization at the front end of the centrifugal impeller and the exhaust transition at the rear end, thereby improving the continuity of airflow introduction and axial discharge.

[0013] In one or more embodiments, the axial flow impeller includes a hub and a plurality of third blades disposed on the outer periphery of the hub. The plurality of third blades are arranged at circumferential intervals along the hub to form an airflow channel with an axial extension component. By providing an axial flow impeller including a hub and a plurality of third blades, and forming an airflow channel with an axial extension component, it is beneficial to perform subsequent work and flow adjustment on the airflow discharged from the centrifugal impeller, thereby increasing the overall pressure rise and improving the downstream flow conditions.

[0014] In one or more embodiments, the third blade has a radial width of 5-20 mm in the hub and extends obliquely at an angle of 10-50° to the axis of the hub. By limiting the radial width of the third blade to 5-20 mm and extending obliquely at an angle of 10-50° to the axis of the hub, it is beneficial to achieve a balance between work capacity, flow capacity, and structural compactness, thereby improving the working efficiency of the axial flow impeller and reducing flow losses.

[0015] In one or more embodiments, the flow guide includes an outlet flow channel located downstream of and communicating with the airflow channel. The outlet flow channel contains a plurality of first guide vanes for guiding airflow along the axial direction of the fan. These first guide vanes are arranged at circumferential intervals along the flow guide. By providing an outlet flow channel communicating with the airflow channel in the flow guide and incorporating a plurality of first guide vanes within the outlet flow channel, it is beneficial to subsequently rectify and directionally guide the airflow discharged from the axial impeller, enabling the airflow to flow more stably along the fan axial direction.

[0016] In one or more embodiments, the first guide vane extends at an angle of 10° to 50° to the axis of the hub, and the first guide vane and the third vane have opposite inclination directions relative to the axis of the hub. By extending the first guide vane at an angle of 10° to 50° to the axis of the hub, and by having the first guide vane and the third vane have opposite inclination directions, it is beneficial to weaken the residual swirling flow in the exhaust airflow of the axial flow impeller, improve the velocity distribution, and enhance the rectification and pressure recovery effects of the guide vane.

[0017] In one or more embodiments, a rectifier is provided between the centrifugal impeller and the axial impeller. The rectifier is located downstream of the duct and upstream of the axial impeller. The rectifier is used to direct the airflow discharged from the duct towards the axial impeller along the axial direction of the fan. By providing a rectifier between the centrifugal impeller and the axial impeller, the airflow discharged from the duct passes through the rectifier before flowing towards the axial impeller. This facilitates pre-rectification and initial deswirl removal of the airflow before it enters the axial impeller, thereby improving the inlet conditions of the axial impeller and enhancing its operational stability.

[0018] In one or more embodiments, the rectifier includes a rectification channel located downstream of and connected to the air duct. The rectification channel contains a plurality of second guide vanes for guiding airflow along the axial direction of the fan. These second guide vanes are arranged at circumferential intervals along the rectifier. By incorporating a rectification channel and multiple second guide vanes in the rectifier, it is beneficial to guide and axially straighten the high-energy airflow output from the centrifugal impeller, reducing the influence of swirling flow and making the airflow entering the axial impeller more uniform and orderly.

[0019] In one or more embodiments, the fan further includes a motor located downstream of the guide vane, the motor's shaft being arranged along the fan's axis, and the centrifugal impeller and the axial impeller being connected to and rotatable with the shaft; the airflow discharged from the guide vane is at least partially directed towards the motor body. By arranging the motor downstream of the guide vane and directing the airflow discharged from the guide vane towards the motor body, it is beneficial to utilize the airflow discharged from the fan to cool the motor, thereby improving the motor's heat dissipation conditions.

[0020] Secondly, this disclosure provides an electric device that includes the aforementioned fan. By applying the fan to the electric device, it is beneficial to enable the device to achieve higher suction capacity and better airflow stability, thereby improving the overall performance of the device.

[0021] The fan and electric equipment disclosed herein, through the sequential arrangement of a centrifugal impeller, an axial impeller, and a guide vane, allow the airflow to undergo a continuous processing process within the fan, including pre-stage pressurization, subsequent stage work, and downstream guidance and rectification. The centrifugal impeller provides a high initial pressure rise to the incoming airflow, while the axial impeller further performs work and adjusts the airflow velocity distribution, reducing swirling intensity. Therefore, compared to a single-stage work structure, this design is more effective in improving overall pressure rise and suction capacity while reducing noise. Simultaneously, the guide vane further guides the airflow discharged from the axial impeller, ensuring more stable axial output and promoting the conversion of residual kinetic energy into static pressure, thereby improving the outlet flow field quality and energy utilization efficiency. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this disclosure or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments recorded in this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 is a schematic diagram of the structure of a fan in one embodiment of this disclosure;

[0024] Figure 2 is a cross-sectional view of a fan in one embodiment of this disclosure;

[0025] Figure 3 is a schematic diagram of the structure of a centrifugal impeller in one embodiment of the present disclosure.

[0026] Figure 4 is a schematic diagram of the structure of an axial flow impeller in one embodiment of the present disclosure;

[0027] Figure 5 is a schematic diagram of the flow guide in one embodiment of this disclosure;

[0028] Figure 6 is a schematic diagram of the rectifier structure in one embodiment of this disclosure.

[0029] Explanation of key figure labels:

[0030] 1-Centrifugal impeller, 11-Cone, 12-First blade, 13-Compression channel, 14-Second blade, 2-Air inlet shroud, 21-Air inlet, 22-Air duct, 221-Air inlet section, 222-Air outlet section, 223-Guide surface, 3-Axial flow impeller, 31-Hub, 32-Third blade, 33-Airflow channel, 4-Guide, 41-Air outlet channel, 42-First guide vane, 5-Rectifier, 51-Rectifier channel, 52-Second guide vane, 6-Motor, 61-Shaft, 62-Body. Detailed Implementation

[0031] To enable those skilled in the art to better understand the technical solutions in this disclosure, the technical solutions in the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. Based on the embodiments in this disclosure, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this disclosure.

[0032] 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.

[0033] It should be noted that when an element is described as being "fixed to" another element, it can be directly attached to the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. In the embodiments shown in this disclosure, directional representations such as up, down, left, right, front, and back are relative and are used to explain the relative structure and movement of different components in this disclosure. These representations are appropriate when the components are in the positions shown in the figures. However, if the description of the component positions changes, then these representations are considered to change accordingly.

[0034] In the field of vacuum cleaners and other small suction devices, the fan is usually the core component that determines the overall suction capacity, noise level, size, and operational reliability of the machine. In existing technologies, to achieve strong suction, a single-stage power unit is often used to pressurize the airflow. This approach is structurally straightforward and facilitates a compact layout, thus it has been widely adopted.

[0035] However, the inventors discovered in their research that as products continue to develop towards higher suction power, miniaturization, and lighter weight, the fan architecture with a single work path is gradually showing its inherent limitations. Especially when the overall size is limited, if it is still desired to continuously improve the suction capacity, it is often necessary to further increase the rotational speed or concentrate the increase in the single-stage work load, which can easily cause a series of chain problems such as increased noise, aggravated vibration, deterioration of local flow, and increased mechanical load.

[0036] Based on this, the inventors further analyzed and discovered that the problem with existing technologies essentially stems from the over-concentration of the airflow energy conversion process, i.e., excessive reliance on a single functional stage to simultaneously perform multiple tasks such as significant pressurization, flow transport, and flow pattern adjustment. While this approach is relatively simple in structure, it easily leads to single-stage components operating under high loads for extended periods, making it difficult to simultaneously manage the velocity distribution, rotational characteristics, and subsequent pressure recovery of the airflow after work, thus limiting further improvements in the overall performance of the fan. Therefore, to overcome the performance bottlenecks of existing technologies and achieve a fan architecture more suitable for small, high-performance suction equipment, the key lies not in simply strengthening a single work-performing component, but in reorganizing the energy conversion path and flow evolution process of the airflow, allowing different stages to undertake more suitable functional tasks.

[0037] Based on the above analysis, the overall implementation idea of ​​this disclosure is: instead of concentrating the airflow pressurization task on a single-stage structure, the process of pressurization, flow transition and pressure recovery is configured in stages according to the evolution law of airflow inside the fan, so that the airflow gradually completes energy conversion and flow optimization in the process of entering, energizing, adjusting and outputting.

[0038] In other words, this disclosure establishes a multi-stage coordinated aerodynamic organization method, where the front stage focuses on providing effective initial energy input to the airflow, the middle stage focuses on further enhancing the energy level and optimizing the flow state based on the front stage, and the rear stage focuses on orderly guiding the airflow, thereby achieving a systematic improvement in overall performance. This approach avoids overloading any single stage, making the functional allocation of each stage within the fan more rational, and thus improving the overall pressure rise capacity and airflow output quality.

[0039] Furthermore, the core idea of ​​this disclosure lies in adapting to the differences in the state of airflow at different stages and organizing the subsequent processing accordingly. In other words, the inventors do not simply connect multiple functional parts in series, but focus on the energy characteristics and flow pattern of the output airflow in the previous stage, so that the subsequent stage can continue to play a role on this basis, thus forming a synergistic relationship that is connected and progressively advanced.

[0040] The airflow no longer undergoes abrupt state changes within the fan, but instead follows a relatively continuous and controllable path to achieve pressure increase, flow adjustment, and stable output. This not only improves energy utilization efficiency but also mitigates the adverse effects caused by excessive local loads, flow distortion, or improper energy dissipation. Consequently, the fan maintains good stability and low noise even under high performance demands, overcoming the limitations of traditional single-path fans that struggle to balance pressure increase, noise, size, and reliability.

[0041] Referring to Figures 1 and 2, a fan in one embodiment of this disclosure includes a centrifugal impeller 1, an air inlet shroud 2, an axial flow impeller 3, and a guide vane 4. The air inlet shroud 2 covers the outside of the centrifugal impeller 1 and has an air inlet 21 located upstream of the centrifugal impeller 1, and an air duct 22 connected to the air inlet 21 and used to guide the airflow to be discharged along the axial direction of the fan. The axial flow impeller 3 is located downstream of the air duct 22 and is used to perform work on the airflow discharged from the air duct 22. The guide vane 4 is located downstream of the axial flow impeller 3 and is used to guide the airflow discharged from the axial flow impeller 3 to flow along the axial direction of the fan.

[0042] The air inlet shroud 2 and the centrifugal impeller 1 together define a spatial path for airflow. The air inlet shroud 2 has an air inlet 21 located upstream of the centrifugal impeller 1 and an air duct 22 connected to the air inlet 21. Outside air can enter from the air inlet 21 and be guided downstream along the overall flow direction of the fan by the air duct 22.

[0043] Centrifugal impeller 1 is arranged inside air inlet shroud 2 and is located in the front stage after the airflow enters. Axial impeller 3 is located downstream of air duct 22, so that the airflow after the centrifugal impeller 1 has done work can continue to flow to axial impeller 3. Flow guide 4 is located downstream of axial impeller 3 to receive the airflow discharged by axial impeller 3 and further guide it.

[0044] Thus, the centrifugal impeller 1, the air inlet shroud 2, the axial flow impeller 3, and the guide vane 4 are arranged sequentially in space along the airflow direction to form a continuous aerodynamic path from air intake, pressurization, rework to rectification and diffusion. This results in the internal components of the fan not being simply spliced ​​together, but forming an integrated structure that connects the front and rear and acts step by step around the same airflow transmission chain.

[0045] The air inlet shroud 2 not only serves to externally enclose and install the centrifugal impeller 1, but also pre-guides the air entering the fan through the air inlet 21 and the air duct 22. That is, the air inlet shroud 2 provides the necessary external boundary for the centrifugal impeller 1, ensuring stable working space, while the air duct 22 limits the airflow path, allowing the air to converge and flow downstream to the functional components in a predetermined direction after entering the fan.

[0046] Since the air duct 22 is used to guide the airflow to exit along the axial direction of the fan, the air inlet shroud 2 also serves to connect the upstream work process with the downstream axial flow requirements. This arrangement avoids excessive airflow dispersion in the initial stage of entering the fan, which helps to improve the orderliness of the airflow when entering the centrifugal impeller 1 and provides relatively stable inlet conditions for subsequent multi-stage work and flow pattern adjustment.

[0047] Centrifugal impeller 1, as the working component located at the front stage, is mainly used to provide initial energy input to the outside air. When air enters the air duct 22 through the air inlet 21, centrifugal impeller 1 performs work on the air, giving it a higher initial pressure rise. At the same time, in the process of increasing the airflow pressure level, centrifugal impeller 1 also gives the airflow a larger circumferential velocity component and higher flow energy.

[0048] Since centrifugal impeller 1 typically features high air pressure and stable flow rate, its placement at the front end of the fan allows for a significant pressure boost to the incoming air at an early stage, thus ensuring the overall suction capacity of the fan. Simultaneously, the airflow output from centrifugal impeller 1 is not directly discharged in its final state but serves as the upstream flow for further processing by the subsequent axial impeller 3. Therefore, centrifugal impeller 1 also plays a role in transmitting high-energy airflow downstream.

[0049] The axial impeller 3 is located downstream of the air duct 22, in an intermediate stage following the centrifugal impeller 1. The airflow, after being worked on by the centrifugal impeller 1, enters the axial impeller 3 under the guidance of the air duct 22. The axial impeller 3 continues to work on this portion of the airflow, further increasing the pressure rise level based on the initial pressure rise already established by the centrifugal impeller 1. Therefore, the axial impeller 3 and the centrifugal impeller 1 are not independent but form a two-stage working relationship. The centrifugal impeller 1 is responsible for establishing the initial pressure base, while the axial impeller 3 provides subsequent pressurization on this basis, ensuring that the entire fan no longer relies on a single stage component to complete the entire pressure rise task.

[0050] Furthermore, the axial impeller 3 is also used to readjust the airflow discharged from the duct 22. Since the airflow output by the centrifugal impeller 1 often has a large circumferential velocity component, without further processing, it can easily affect the stable axial output of subsequent airflow. The axial impeller 3 can redistribute the airflow velocity distribution and reduce the swirling intensity in the airflow, allowing the airflow to gradually transition from the high-energy rotational state formed by the centrifugal work of the preceding stage to a state more suitable for axial conveying and subsequent diffusion.

[0051] Furthermore, since the upstream centrifugal impeller 1 has already compressed the airflow to a certain extent, the fluid density has increased accordingly. Therefore, when the axial impeller 3 handles this part of the airflow, it can effectively do work under a smaller blade height. This not only helps to reduce the axial or radial structural load of the fan, but also reduces the losses caused by tip clearance leakage, thus balancing aerodynamic performance and structural compactness.

[0052] The guide vane 4 is located downstream of the axial impeller 3, at the rear stage of the entire airflow path. It receives the airflow discharged from the axial impeller 3 and guides this portion of the airflow along the axial direction of the fan. The guide vane 4 and the axial impeller 3 form a corresponding relationship, that is, the axial impeller 3 is responsible for outputting the airflow after it has undergone further work and flow pattern adjustment, while the guide vane 4 further refines and converts the energy of the airflow.

[0053] Specifically, the main function of the flow guide 4 is to gradually convert the residual kinetic energy in the airflow into static pressure, thereby achieving diffusion and pressure recovery by removing residual swirl and slowing down the airflow. In other words, the flow guide 4 not only serves a guiding function but also stabilizes the flow field downstream of the axial impeller 3. With the flow guide 4 in place, the airflow can further reduce its rotational tendency and improve its velocity distribution after leaving the axial impeller 3, and be discharged axially in a more stable and uniform manner, thus improving the overall pressure recovery effect and outlet flow quality.

[0054] In one exemplary embodiment, as shown in Figures 2 and 3, the centrifugal impeller 1 includes a conical portion 11 disposed in the air duct 22 along the axial direction of the fan, and the outer diameter of the conical portion 11 gradually decreases in the direction pointing towards the air inlet 21.

[0055] The cone 11 is located in the middle region of the centrifugal impeller 1 and, together with the air duct 22, defines an internal flow space for airflow to enter, adhere to, and transition. The axis of the cone 11 is basically aligned with the axis of the fan, so that the cone 11 forms a central guide body extending axially inside the fan.

[0056] The air inlet 21 is located upstream of the centrifugal impeller 1. After the outside air enters through the air inlet 21, it first encounters the tapered shape of the cone 11, which gradually tapers in the direction of the air inlet 21. That is, the end of the cone 11 facing the air inlet 21 is relatively pointed, while the end away from the air inlet 21 is relatively wide. This gives the cone 11 a tapered inlet shape on the air intake side, while on the side away from the air intake, it forms a structural foundation more suitable for receiving subsequent work and airflow transfer.

[0057] The cone 11 and the wall boundary of the air duct 22 form a mating relationship to jointly create the intake environment near the centrifugal impeller 1. On the one hand, the air duct 22 provides an overall path for the outside air to converge from the air inlet 21 to the centrifugal impeller 1; on the other hand, the cone 11, through its shape feature of gradually narrowing outer diameter in the direction pointing towards the air inlet 21, provides central guidance and contour constraint for the airflow entering the air duct 22.

[0058] Because the outer diameter of the end of the cone 11 near the air inlet 21 is smaller, the airflow can be distributed more smoothly around the outer periphery of the cone 11 during the initial entry stage, avoiding an overly abrupt obstruction in the center. Compared to a central body with abrupt changes in front shape or a large front size, the tapered cone 11 is more conducive to reducing the flow impact in the initial stage of air intake, allowing the air to transition to the periphery of the centrifugal impeller 1 in a more gradual manner, thereby improving the connection between the air inlet 21 and the centrifugal impeller 1.

[0059] During operation, the centrifugal impeller 1 needs to accelerate and input energy into the incoming air. The initial state of the airflow before entering the centrifugal impeller 1 directly affects the flow performance during the subsequent work process. If the central area lacks a reasonable flow guiding structure, or if the shape of this area changes too drastically, the airflow entering the air duct 22 is prone to local separation, backflow, or uneven velocity distribution, thereby affecting the uniformity of air intake of the centrifugal impeller 1.

[0060] The cone 11 adopts a shape that gradually tapers along the air intake direction, allowing the outside air to gradually adapt to the changes in the internal flow channel boundary as it approaches the centrifugal impeller 1, thereby reducing additional flow losses caused by geometric abrupt changes. This structure is not limited to the external cone shape, but rather provides a smooth flow interface for the airflow to transition from a free-entry state to a controlled confluence state through a continuously varying outer diameter.

[0061] As part of the centrifugal impeller 1, the cone 11 not only participates in forming the overall profile of the centrifugal impeller 1, but also provides installation, support, or profile references for other functional structures of the centrifugal impeller 1. As the outer diameter of the cone 11 gradually increases in the direction away from the air inlet 21, its peripheral space also changes accordingly, allowing the centrifugal impeller 1 to form a working area in the downstream region that is more suitable for airflow force and direction. In other words, the front section of the cone 11 is more inclined to guide and straighten the incoming flow, while the rear section undertakes more of the profile transition function that matches the overall working process of the centrifugal impeller 1.

[0062] Specifically, referring to Figures 2 and 3, the centrifugal impeller 1 includes a plurality of first blades 12 arranged around the axis of the cone 11, and the plurality of first blades 12 are spaced apart on the outer peripheral surface of the cone 11; the first blades 12 extend at least partially along the axial and circumferential spiral of the cone 11, so that a compression channel 13 with an axial extension component is formed between two adjacent first blades 12.

[0063] Multiple first blades 12 are arranged circumferentially around the cone 11, creating separate flow regions between each first blade 12. Since the first blades 12 are located on the outer circumferential surface of the cone 11, their inner boundaries connect with the outer surface of the cone 11, while their outer boundaries extend towards the outer periphery of the air duct 22. This allows the airflow entering the vicinity of the centrifugal impeller 1 to form a constrained flow path between the cone 11 and adjacent first blades 12. With this configuration, the cone 11 no longer merely serves as a central support but, together with the multiple first blades 12, defines the main working area of ​​the centrifugal impeller 1, and synergistically influences the introduction, compression, and transport of airflow during rotation.

[0064] The first blade 12 extends spirally along the axial and circumferential directions of the cone 11 in at least part. That is, the first blade 12 does not unfold in a purely radial or purely circumferential direction, but presents a spatial form that combines axial extension and circumferential encirclement based on the shape of the cone 11.

[0065] Specifically, when the first blade 12 is arranged around the axis of the cone 11, it not only gradually deflects circumferentially, but also extends a certain length along the axial direction of the cone 11, giving the first blade 12 an overall spiral-like layout. This extension allows the first blade 12 to better conform to the airflow transition from the inlet side to the downstream region, avoiding an abrupt change in flow direction immediately after the airflow enters the working area of ​​the centrifugal impeller 1.

[0066] Based on the arrangement of multiple first blades 12 spaced apart along the outer periphery of the cone 11, a compression channel 13 is formed between adjacent first blades 12. Since the first blades 12 extend spirally along the axial and circumferential directions of the cone 11 at least partially, the compression channel 13 exhibits a spatial characteristic with an axial extension component. The term "with an axial extension component" here mainly refers to the fact that the compression channel 13, in its overall extension direction, also has a continuous guiding trend in the axial direction, following the spatial extension pattern of the first blades 12. That is, when the airflow is acted upon by the centrifugal impeller 1, it not only undergoes circumferential acceleration and energy enhancement but also propagates downstream along the fan axis.

[0067] The cone 11 forms the inner boundary of the compression channel 13, the two adjacent first blades 12 form the lateral boundary of the compression channel 13, and the outer side of the compression channel 13 connects with the spatial region corresponding to the air duct 22. That is, the compression channel 13 is essentially a flow space jointly defined between the cone 11, the first blades 12, and the boundary of the air duct 22.

[0068] After entering the fan, outside air is guided by the first blade 12 into the compression channel 13 between adjacent first blades 12, and flows along the compression channel 13 during the rotation of the centrifugal impeller 1. Because the first blade 12 itself has a spiral extension characteristic, the airflow within the compression channel 13 does not diffuse randomly, but rather gradually acquires velocity and pressure changes along the path defined by the blade shape. This structure helps to create a relatively stable inter-blade flow state after the airflow enters the centrifugal impeller 1, reducing local turbulence, separation, or additional losses caused by abrupt changes in flow direction or discontinuities at the channel boundaries.

[0069] Multiple first blades 12 are arranged around the axis of the cone 11 and extend spirally along the axial and circumferential directions of the cone 11, mainly to balance the centrifugal work requirements and the downstream axial transport requirements. If the first blades 12 only emphasize energy input in the centrifugal direction, the airflow is prone to flow turbulence or poor axial connection in the subsequent transition process after obtaining a high circumferential velocity component. However, by giving the first blades 12 a certain axial extension tendency, the airflow can begin to establish the motion basis for downstream transmission inside the centrifugal impeller 1, thereby making it easier for the airflow output by the centrifugal impeller 1 to match the subsequent flow channel or downstream components.

[0070] Further, referring to Figure 3, the compression channel 13 is provided with a second blade 14 for flow diversion. The second blade 14 extends from the middle region of the compression channel 13 to the outlet end of the compression channel 13. The second blade 14 is located between two adjacent first blades 12 and is located in the internal region of the compression channel 13, thereby further subdividing the compression channel 13, which is originally defined by the cone 11 and the two first blades 12, into multiple local flow regions.

[0071] The second blade 14 is arranged along the extension direction of the compression channel 13, with its extension starting in the middle region of the compression channel 13 and ending at the outlet end of the compression channel 13, that is, the end near the bottom surface of the cone 11. With this arrangement, the second blade 14 does not directly intercept the incoming flow in the initial stage of air intake, but rather further diverts and guides the airflow in the compression channel 13 after the airflow has entered the compression channel 13 and formed a certain flow trend under the action of the first blade 12.

[0072] Thus, the second blade 14 forms a spatial relationship with the first blade 12, the cone 11, and the compression channel 13. The first blade 12 mainly constitutes the lateral boundary of the compression channel 13 and undertakes the main work-performing capacity of the preceding stage. The cone 11 forms the inner contour basis of the compression channel 13. The second blade 14 is located inside the compression channel 13 and serves as an auxiliary flow guiding component in the main work-performing channel to reorganize and optimize the local flow field within the compression channel 13.

[0073] The blade shape of the second blade 14 is preferably similar to that of the first blade 12, and can be understood as a scaled-down version of the first blade 12. That is, the second blade 14 maintains the same overall extension trend, bending orientation, and airflow guidance direction as the first blade 12, but its height and size are smaller than the first blade 12. Precisely because the second blade 14 is smaller in size than the first blade 12, after being placed inside the compression channel 13, the second blade 14 will not directly dominate the airflow work process of the entire channel like the first blade 12, but will instead undertake more functions of local rectification, diversion, and guidance.

[0074] In other words, the first blade 12 and the second blade 14 form a composite blade group structure with main and auxiliary cooperation. The first blade 12 is mainly used to do work on the air to generate suction and establish the pressure rise of the front stage. The second blade 14, without significantly increasing the overall resistance of the centrifugal impeller 1, assists in guiding the airflow that is already in the compression channel 13, so that the airflow remains more stable and orderly as it flows from the middle of the compression channel 13 to the outlet end.

[0075] After the airflow enters the compression channel 13, it gradually acquires higher velocity and pressure changes under the influence of the first blade 12. Especially during the process of propagation along the compression channel 13 towards the outlet, the local flow velocity, flow direction, and pressure gradient may change significantly. If the airflow inside the compression channel 13 relies entirely on the large-scale flow space between the two first blades 12 to constrain the airflow, the airflow may experience flow deviation, enhanced vortices, or uneven velocity distribution in local areas, thus affecting the flow stability of the later section of the compression channel 13. The second blade 14 is located between the middle region and the outlet of the compression channel 13, which can supplement and refine the airflow distribution in this stage, so that the originally wide inter-blade channel is appropriately subdivided in the later section, thereby mitigating the adverse effects of abrupt changes in the local flow field.

[0076] In an exemplary embodiment, as shown in FIG2, the air duct 22 includes an air inlet section 221 and an air outlet section 222. The wall profile of the air inlet section 221 is adapted to the outer edge of a plurality of first blades 12. The air outlet section 222 surrounds the outer periphery of the outlet end of the compression flow channel 13. The air outlet section 222 has a guide surface 223 for guiding the airflow to be discharged along the axial direction of the fan.

[0077] The inlet section 221 and the outlet section 222 are connected sequentially along the airflow direction and together form an airflow guiding passage arranged around the centrifugal impeller 1. The inlet section 221 is located in the upstream region where the airflow enters the centrifugal impeller 1 and mainly cooperates with the outer edges of multiple first blades 12; the outlet section 222 is located on the outer periphery of the outlet end of the compression channel 13 and mainly cooperates with the exhaust process downstream of the compression channel 13.

[0078] The wall profile of the air inlet section 221 is adapted to the outer edge of the plurality of first blades 12, that is, the air inlet section 221 is specifically designed according to the spatial arrangement profile of the plurality of first blades 12. Since the plurality of first blades 12 are arranged around the axis of the cone 11, and the first blades 12 extend spirally along the axial and circumferential directions of the cone 11 in at least part, the outer edges of the plurality of first blades 12 generally form an approximately frustum-shaped arrangement structure.

[0079] Based on this, the wall profile of the air inlet section 221 is adapted to the approximately frustum-shaped arrangement structure, so that the air inlet section 221 can form an envelope boundary corresponding to the shape of the first blade 12 around the centrifugal impeller 1. With this setting, the spatial gap between the air inlet section 221 and the multiple first blades 12 can be kept within a reasonable range. It will not cause excessive diffusion, velocity attenuation or local backflow of airflow before entering the working area of ​​the centrifugal impeller 1 due to excessive gap, nor will it cause interference to the rotation of the centrifugal impeller 1 or cause flow blockage due to excessive gap.

[0080] Multiple first blades 12 constitute the main working unit of the centrifugal impeller 1, while the air inlet section 221 is located in the outer area of ​​the multiple first blades 12, and together with the multiple first blades 12, defines the external inlet space before the airflow enters the compression channel 13. That is, after the outside air enters through the air inlet 21, it does not rush directly towards the centrifugal impeller 1 without restraint, but is gradually converged to the working area corresponding to the multiple first blades 12 under the guidance of the wall contour of the air inlet section 221.

[0081] Since the wall profile of the air inlet section 221 is adapted to the outer edge of the multiple first blades 12, when the air approaches the first blades 12, it can flow along the boundary path that is coordinated with the outer edge of the first blades 12. This helps to reduce the local flow direction change on the air inlet side, improve the uniformity of the incoming flow distribution, and make it easier for each compression channel 13 to obtain relatively consistent air inlet conditions on the inlet side.

[0082] The outlet section 222 is located downstream of the compression channel 13, and its main function is to collect, transition, and guide the airflow discharged from the compression channel 13. After gaining high flow energy within the compression channel 13, the airflow will be discharged from the outlet end of the compression channel 13. If there is a lack of a reasonable peripheral guiding structure around the outlet end, the airflow may rapidly diffuse after leaving the compression channel 13, resulting in turbulent velocity distribution, enhanced local swirling, or insufficient energy utilization. The outlet section 222 is located around the outlet end of the compression channel 13, essentially providing a downstream transition space for the airflow discharged from the compression channel 13, allowing the airflow to continue downstream along a predetermined path after leaving the main working area of ​​the centrifugal impeller 1.

[0083] The air outlet section 222 alters and constrains the airflow direction through the contour design of the guide surface 223. Since the airflow typically possesses a large circumferential velocity component and high kinetic energy after being powered by the centrifugal impeller 1, to ensure better flow of this airflow towards the subsequent stage structure, an axial discharge tendency needs to be gradually established downstream of the centrifugal impeller 1. The guide surface 223 is designed to reorganize the direction of the high-energy airflow discharged from the compression channel 13, gradually reducing the tendency for disordered diffusion as the airflow flows along the air outlet section 222 and guiding it towards axial discharge from the fan.

[0084] In one exemplary embodiment, as shown in Figures 2 and 4, the axial flow impeller 3 includes a hub 31 and a plurality of third blades 32 disposed on the outer periphery of the hub 31. The plurality of third blades 32 are arranged at circumferential intervals along the hub 31 to form an airflow channel 33 having an axial extension component.

[0085] The hub 31 is located in the central region of the axial impeller 3 and is arranged along the axis of the fan. Multiple third blades 32 are arranged circumferentially around the outer periphery of the hub 31, so that the hub 31 and the multiple third blades 32 together constitute a rotating component that can further perform work on the airflow and realize flow adjustment. On the one hand, the hub 31 serves as the mounting base and load-bearing body for the multiple third blades 32, providing stable connection support for the multiple third blades 32; on the other hand, the hub 31 also forms the central boundary of the inner side of the axial impeller 3, so that the airflow is mainly distributed in the annular area between the outer periphery of the hub 31 and the outer flow channel when passing through the axial impeller 3.

[0086] Each adjacent third blade 32 forms a separate flow region. Because multiple third blades 32 are arranged sequentially in the circumferential direction, multiple circumferentially distributed inter-blade passages are formed on the outer circumference of the entire axial impeller 3. When airflow passes through the axial impeller 3, it can enter each inter-blade region and flow downstream in a predetermined direction under the combined action of the multiple third blades 32. This circumferentially spaced arrangement of the multiple third blades 32 allows the axial impeller 3 to apply torque to a larger range of airflow during rotation, improving its work-capacity.

[0087] An airflow channel 33 with an axial extension component is formed between two adjacent third blades 32. The overall extension direction of the airflow channel 33 has an axial extension tendency towards the downstream of the fan in space. That is, after the airflow enters the axial flow impeller 3, it is not only affected by the energy brought by the rotation of the third blade 32, but can also continue to be transmitted and output along the fan axis under the action of the third blade 32.

[0088] The axial impeller 3 is located downstream of the centrifugal impeller 1, and therefore processes the high-energy airflow discharged after the upstream centrifugal impeller 1 has done work. This airflow typically already has a certain pressure base and a large circumferential velocity component, so its flow state upon entering the axial impeller 3 differs significantly from that of typical initial intake air. The axial impeller 3 forms an airflow channel 33 with an axial extension component through multiple third blades 32, allowing the high-energy airflow output from the upstream to be further received, organized, and utilized in subsequent stages. The multiple third blades 32 reorganize the incoming flow through inter-blade channels (airflow channels 33), ensuring that the airflow continues to receive energy input while maintaining its downstream transport trend, and gradually reducing the adverse swirling effects brought by the upstream centrifugal impeller 1.

[0089] Furthermore, the airflow channel 33 formed by multiple third blades 32 not only serves a conveying function but also adjusts the velocity distribution. The airflow discharged from the centrifugal impeller 1 often exhibits a significant circumferential component and local non-uniformity before entering the axial impeller 3. Without proper downstream confinement, the airflow is prone to turbulence, flow deviation, or increased local losses as it flows downstream. The airflow channel 33, with its axially extended component, allows for the reorganization of the flow direction, velocity distribution, and local flow field state as the airflow passes through the axial impeller 3.

[0090] Specifically, as shown in Figures 2 and 4, the third blade 32 has a radial width of 5~20mm in the hub 31 and extends at an angle of 10~50° with the axis of the hub 31.

[0091] The radial width of the third blade 32 in the hub 31 is limited to 5~20mm, mainly based on the comprehensive balance between the axial stage work capacity, flow resistance, and structural compactness under the conditions of wind turbine miniaturization. If the radial width of the third blade 32 in the hub 31 is too small, the area of ​​the third blade 32 that acts on the airflow will be insufficient, and the interaction between the airflow and the third blade 32 when passing through the axial impeller 3 will be weakened. This is not conducive to effectively receiving the upstream flow, nor is it conducive to forming sufficient downstream work capacity within the limited axial space.

[0092] The third blade 32 extends at an angle of 10° to 50° with the axis of the hub 31. This angle allows the airflow to flow downstream along the fan axis when passing through the airflow channel 33 between adjacent third blades 32, and also gradually changes the velocity distribution and weakens unfavorable swirls under the guidance of the third blade 32. The airflow from the centrifugal impeller 1 usually has a large circumferential velocity component. If the angle between the third blade 32 and the axis of the hub 31 in the axial impeller 3 is too small, the guiding and rework effect of the third blade 32 on this part of the airflow is relatively limited, and the airflow is more likely to pass along the original flow inertia, which is not conducive to fully realizing the subsequent energy replenishment and flow pattern correction.

[0093] If the included angle is too large, the deflection effect of the third blade 32 on the airflow will be too strong. Although this may improve the local work capacity, it may also easily cause the airflow to deteriorate on the blade surface, thereby increasing local losses and affecting the stability within the airflow channel 33. Limiting the included angle between the third blade 32 and the axis of the hub 31 to the range of 10~50° is beneficial to achieving a more suitable balance between the guiding capacity and flow loss of the third blade 32, so that the airflow can continue to do work when passing through the axial flow impeller 3, while maintaining a relatively smooth axial transition trend.

[0094] In an exemplary embodiment, as shown in Figures 2 and 5, the flow guide 4 includes an air outlet channel 41 located downstream of and connected to the airflow channel 33. The air outlet channel 41 is provided with a plurality of first guide vanes 42 for guiding the airflow along the axial direction of the fan. The plurality of first guide vanes 42 are arranged at intervals along the circumference of the flow guide 4.

[0095] The outlet flow channel 41 is located after the axial impeller 3, forming a downstream flow space that receives the airflow discharged from the airflow channel 33. After passing through the airflow channel 33, which is defined by multiple third blades 32, the airflow continues into the outlet flow channel 41, which is connected to the airflow channel 33, thus extending the flow boundary downstream of the axial impeller 3. Through this connection, the outlet flow channel 41 can receive the airflow discharged from the airflow channel 33, allowing the airflow to continue flowing along a predetermined path after leaving the axial impeller 3, avoiding sudden diffusion of high-speed airflow at the outlet, which could cause local backflow, turbulent flow, or disordered dissipation of kinetic energy.

[0096] Multiple first guide vanes 42 are provided within the air outlet duct 41. These first guide vanes 42 are circumferentially distributed around the fan axis, forming multiple circumferentially separated local flow regions between adjacent first guide vanes 42. This redistributes and continuously constrains the airflow entering the air outlet duct 41. Because the multiple first guide vanes 42 are located within the air outlet duct 41 and are spaced circumferentially along the guide vane 4, the first guide vanes 42 and the wall of the air outlet duct 41 together define multiple guiding spaces. This allows the airflow to undergo flow direction correction and velocity adjustment within these multiple guiding spaces as it flows through the guide vane 4. Consequently, the flow state inside the guide vane 4 is more controllable, which is beneficial for improving the uniformity and stability of the downstream flow field of the axial impeller 3.

[0097] Although the airflow discharged from the upstream axial impeller 3 has undergone rework and a certain degree of flow pattern adjustment, it may still retain some circumferential velocity components or local velocity non-uniformity. Therefore, the multiple first guide vanes 42 set in the guide vane 4 can make subsequent corrections for this flow characteristic, so that the airflow at different circumferential positions can be guided in a more balanced way, thereby reducing the local flow field difference and improving the velocity uniformity of the entire outlet section.

[0098] Specifically, as shown in Figures 2 and 5, the first guide vane 42 extends at an angle of 10 to 50° to the axis of the hub 31, and the first guide vane 42 and the third blade 32 are inclined in opposite directions relative to the axis of the hub 31.

[0099] The spatial attitude of the first guide vane 42 needs to be adapted to the upstream airflow state, so as to weaken the residual rotation trend without causing new flow losses due to excessively strong guidance. Limiting the angle between the first guide vane 42 and the axis of the hub 31 to 10~50° can achieve a balance between guidance capacity, flow capacity and flow smoothness, so that the first guide vane 42 can exert sufficient directional constraint on the airflow and allow the airflow to maintain a continuous and stable passage along the outlet flow channel 41.

[0100] The third blade 32, as a rotating work component, imparts a certain rotational tendency to the airflow as it propels it downstream. The first guide vane 42, as a stationary guide component, counteracts and redistributes this rotational tendency through its opposite tilt direction to the third blade 32. In other words, the third blade 32 is primarily responsible for continuing to perform work on the airflow and establishing the foundation for subsequent flow, while the first guide vane 42 is primarily responsible for receiving the airflow discharged from the third blade 32 and gradually weakening the circumferential component that is detrimental to axial stability.

[0101] When the third blade 32 of the front stage is tilted in one circumferential direction, the first guide vane 42 of the rear stage is tilted in the opposite circumferential direction. This allows the airflow entering the guide vane 4 to gradually weaken the swirling intensity during contact and passage with the first guide vane 42, thus making the airflow more inclined to flow along the fan axis. The third blade 32 and the first guide vane 42 are corresponding to each other along the airflow direction and form an opposite relationship in circumferential tilt orientation. This makes the axial flow impeller 3 and the guide vane 4 no longer two independent components, but rather a continuous action path around the same airflow, forming a front-stage power boosting and rear-stage rectification.

[0102] In an exemplary embodiment, as shown in Figures 2 and 6, a rectifier 5 is provided between the centrifugal impeller 1 and the axial impeller 3. The rectifier 5 is located downstream of the air duct 22 and upstream of the axial impeller 3. The rectifier 5 is used to make the airflow discharged from the air duct 22 flow along the axial direction of the fan to the axial impeller 3.

[0103] The air duct 22, rectifier 5, and axial impeller 3 are connected sequentially along the airflow direction, forming an intermediate transition unit between the pre-stage pressurization structure and the intermediate stage work-continuing structure. That is, after the centrifugal impeller 1 completes the pre-stage work, the airflow does not directly enter the axial impeller 3, but is first discharged through the air duct 22 and flows into the rectifier 5, and then flows to the axial impeller 3 after the rectifier 5 is activated.

[0104] With this arrangement, the rectifier 5 is actually located between the output airflow of the centrifugal impeller 1 and the inlet airflow of the axial impeller 3. On the one hand, it receives the high-energy airflow from the air duct 22, and on the other hand, it provides the axial impeller 3 with pre-treated incoming flow conditions. Thus, the centrifugal impeller 1, the rectifier 5 and the axial impeller 3 form a structural relationship of front-to-back cooperation and step-by-step transition.

[0105] The airflow discharged from duct 22 has already been subjected to the work of centrifugal impeller 1, exhibiting high flow energy and significant swirling characteristics. If this airflow directly enters axial impeller 3, axial impeller 3, while continuing to perform work, also needs to undertake a strong task of correcting the incoming flow, which can easily lead to excessive local load, uneven inlet flow, or deterioration of the inter-blade flow field. Therefore, a rectifier 5 is installed between duct 22 and axial impeller 3. This rectifier adapts to the actual flow characteristics of the preceding airflow, performing preliminary diffusion and deswirl treatment before the airflow enters axial impeller 3, thus pre-adjusting the airflow velocity distribution, flow direction, and energy state. This makes the incoming flow facing axial impeller 3 more orderly, thereby improving the stability of subsequent work performed by axial impeller 3.

[0106] The rectifier 5 mainly performs preliminary diffusion and despinning functions. Preliminary diffusion refers to the rectifier 5 converting some of the kinetic energy in the airflow after receiving the airflow from the duct 22, so that the airflow begins to establish a relatively smooth pressure recovery process before flowing towards the axial impeller 3. Despinning refers to the rectifier 5 weakening the larger circumferential velocity component in the airflow output from the centrifugal impeller 1, so that the airflow gradually transitions from a deflected state to an axial flow state that is more suitable for subsequent axial flow processing.

[0107] This staged diffusion method avoids concentrating all diffusion and deswirl tasks in a single location. Relying solely on a single-stage high-load diffusion causes the airflow to decelerate and change direction drastically over a short distance, easily inducing flow separation, local stall, severe eddies, and velocity distortion. This not only affects pressure recovery but also introduces significant noise problems. However, the rectifier 5 first pre-processes the airflow exiting the duct 22, and then the subsequent guide vane 4 further improves the flow field. This allows the airflow to gradually complete energy conversion and flow direction correction in multiple stages, thereby reducing the flow separation risk associated with single-stage high-load diffusion. Furthermore, while achieving higher pressure recovery, it suppresses noise problems caused by local stall, severe eddies, and velocity distortion.

[0108] Specifically, as shown in Figures 2 and 6, the rectifier 5 includes a rectifier channel 51 located downstream of the air duct 22 and connected to the air duct 22. The rectifier channel 51 is provided with a plurality of second guide vanes 52 for guiding the airflow along the axial direction of the fan. The plurality of second guide vanes 52 are arranged at intervals along the circumference of the rectifier 5.

[0109] The rectifying channel 51 is equipped with multiple second guide vanes 52, which are arranged at circumferential intervals along the rectifier 5. This divides the interior of the rectifying channel 51 into multiple circumferentially distributed local flow guiding regions. The two adjacent second guide vanes 52 together define a local flow space suitable for airflow, so that the airflow entering the rectifying channel 51 no longer advances randomly in a large-scale free diffusion manner, but is gradually transported downstream in a predetermined direction under the constraint of the multiple second guide vanes 52.

[0110] The second guide vane 52 is used to guide the airflow along the axial direction of the fan. The airflow output from the centrifugal impeller 1 usually has a large circumferential velocity component. If it enters the axial impeller 3 directly without pretreatment, the axial impeller 3 will have to withstand strong inlet swirl interference while continuing to do work, which can easily lead to deterioration of the inter-blade flow state, increased local load, and decreased efficiency. The second guide vane 52 can use its own guiding surface to gradually weaken the unfavorable rotational component in the airflow and promote the airflow to establish a more obvious axial flow trend, so that the airflow has a better inlet flow state when it approaches the axial impeller 3.

[0111] The tilt direction of the second guide vane 52 is preferably the same as that of the first guide vane 42. The second guide vane 52 is located upstream of the axial flow impeller 3, and the first guide vane 42 is located downstream of the axial flow impeller 3. Although they act on different flow stages before and after the axial flow impeller 3, they both undertake the task of making the airflow more axially ordered. Setting the tilt direction of the second guide vane 52 to be the same as that of the first guide vane 42 is beneficial to make the rectifier 5 and the guide vane 4 form a consistent design logic in terms of flow orientation, that is, to perform staged straightening of the airflow before and after the axial flow impeller 3 along similar guiding principles. The airflow is pre-rectified by the second guide vane 52 before entering the axial flow impeller 3, and further rectified and pressure restored by the first guide vane 42 after leaving the axial flow impeller 3. The guiding trend in the entire airflow path is more continuous, which can reduce the repeated deflection of the flow and additional losses caused by excessive differences in the guiding orientation of the preceding and following stages.

[0112] In one exemplary embodiment, the outer peripheral wall of the air inlet shroud 2, the outer peripheral wall of the rectifier 5, and the outer peripheral wall of the guide 4 together constitute the outer shell of the fan. The three are arranged sequentially along the fan axis and form a continuously connected external enclosure structure through nesting.

[0113] Specifically, the lower end of the outer peripheral wall of the air inlet shroud 2 is nested with the upper end of the outer peripheral wall of the rectifier 5, and the lower end of the outer peripheral wall of the rectifier 5 is nested with the upper end of the outer peripheral wall of the guide vane 4. This allows the air inlet shroud 2, rectifier 5, and guide vane 4 to be connected end-to-end axially and to collectively form the outer casing of the fan circumferentially. Through this axially nested assembly method, the air inlet shroud 2, rectifier 5, and guide vane 4 form a mutually nesting and mutually limiting fit structure in the connection area. This allows the three components to form a more stable and continuous shell profile along the fan axial direction after assembly, while also ensuring the relative positional accuracy between the functional modules.

[0114] When the outer walls of the three components are sequentially connected axially, they can form an internal-external correspondence with the internal flow channels of the centrifugal impeller 1, rectifier 5, and guide vane 4. That is, the outer shell structure is segmented according to the extension of the internal airflow processing path, and then integrated into a whole through nesting. This arrangement not only allows different functional areas to be structurally protected by corresponding components, but also enables the entire fan shell to form a modular structure according to the arrangement of the internal flow channels and functional modules, thus balancing integrity with the convenience of segmented manufacturing and assembly.

[0115] In one exemplary embodiment, as shown in Figures 1 and 2, the fan also includes a motor 6 located downstream of the guide vane 4. The rotating shaft 61 of the motor 6 is arranged along the axis of the fan. The centrifugal impeller 1 and the axial impeller 3 are connected to the rotating shaft 61 and can rotate with the rotating shaft 61. At least part of the airflow discharged from the guide vane 4 blows toward the body 62 of the motor 6.

[0116] The motor 6 is located in the downstream region of the entire airflow path. The motor 6's shaft 61 is arranged along the fan's axis, thereby arranging the motor 6, centrifugal impeller 1, axial impeller 3, rectifier 5, and guide vane 4 around the same axis, forming a compact assembly configuration with a continuous airflow path. Both the centrifugal impeller 1 and the axial impeller 3 are connected to the shaft 61 and can rotate with it. The motor 6, as the fan's power source, simultaneously drives the upstream centrifugal impeller 1 and the downstream axial impeller 3 through the shaft 61, enabling the centrifugal impeller 1 and the axial impeller 3 to work collaboratively under a unified power input.

[0117] The motor 6 is located downstream of the guide vane 4, corresponding to the outlet airflow path of the guide vane 4. The airflow discharged from the guide vane 4 is transmitted axially downstream and at least partially blown onto the body 62 of the motor 6. That is, the motor 6 is located in the airflow action area downstream of the guide vane 4, so that the airflow output from the guide vane 4 can not only complete the exhaust task of the fan itself, but also provide additional cooling for the motor 6, thereby utilizing the exhaust airflow that already exists during the operation of the fan to cool the motor 6.

[0118] Centrifugal impeller 1 and axial impeller 3 continuously perform work on the airflow during fan operation, while motor 6 continuously outputs driving force. Motor 6 body 62 typically generates heat during long-term operation. If the heat dissipation of motor 6 is insufficient, its internal temperature rise may increase, affecting motor 6 efficiency, operational stability, and service life. Therefore, this disclosure does not add an independent cooling air path, but instead fully utilizes the existing main airflow path within the fan, placing motor 6 downstream of guide vane 4 so that the airflow discharged from guide vane 4 blows towards motor 6 body 62. With this configuration, the fan can simultaneously cool motor 6 while pressurizing, conveying, and guiding the airflow, thereby improving the overall thermal management capability of the machine without significantly increasing additional structural complexity.

[0119] This disclosure also provides an electric device that includes the aforementioned fan. This electric device is capable of operating under electrical power and uses the fan to generate, transport, and discharge airflow to meet the functional requirements of airflow organization in different application scenarios such as cleaning, heat dissipation, or ventilation.

[0120] Electric equipment can be of the following types: cleaning equipment, heat dissipation equipment, or ventilation equipment. Cleaning equipment includes, for example, vacuum cleaners, floor scrubbers, or other cleaning devices that require airflow for intake and exhaust. Heat dissipation equipment includes, for example, devices that provide convection cooling for electronic components or battery packs. Ventilation equipment includes, for example, devices used for indoor air circulation or local ventilation.

[0121] The fan can be installed in the internal space of the electric equipment as a power source component. The fan works in conjunction with the housing, duct structure or functional module of the electric equipment so that the air inlet of the fan can be connected to the air intake path of the electric equipment and the air outlet of the fan can be connected to the exhaust path of the electric equipment, thereby forming a continuous airflow path during operation.

[0122] The electric equipment may also include a power supply component and a control component for supplying power to the fan and driving the fan. The power supply component provides working power to the fan motor, and the control component can adjust the fan speed and output according to the working mode of the electric equipment or external environmental conditions, so that the fan can output the required air volume and pressure under different working conditions.

[0123] In summary, the fan and electric equipment provided in this disclosure, through the sequential arrangement of a centrifugal impeller, an axial impeller, and a guide vane, allow the airflow to undergo a continuous processing process within the fan, including pre-stage pressurization, subsequent stage work, and downstream guidance and rectification. The centrifugal impeller provides a high initial pressure rise to the incoming airflow, while the axial impeller further performs work and adjusts the airflow velocity distribution, reducing swirling intensity. Therefore, compared to a single-stage work structure, this design is more effective in improving overall pressure rise and suction capacity while reducing noise. Simultaneously, the guide vane further guides the airflow discharged from the axial impeller, ensuring more stable axial output and promoting the conversion of residual kinetic energy into static pressure, thereby improving the outlet flow field quality and energy utilization efficiency.

[0124] It will be apparent to those skilled in the art that this disclosure is not limited to the details of the exemplary embodiments described above, and that this disclosure can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of this disclosure 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 disclosure. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0125] 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. A fan, characterized in that, include: Centrifugal impeller; An air inlet shroud is installed on the outside of the centrifugal impeller and has an air inlet located upstream of the centrifugal impeller and an air duct connected to the air inlet and used to guide the airflow to be discharged along the axial direction of the fan; an axial flow impeller is located downstream of the air duct and is used to perform work on the airflow discharged from the air duct; a flow guide is located downstream of the axial flow impeller and is used to guide the airflow discharged from the axial flow impeller to flow along the axial direction of the fan.

2. The fan according to claim 1, characterized in that, The centrifugal impeller includes a conical portion disposed within the air duct along the axial direction of the fan, and the outer diameter of the conical portion gradually decreases in the direction pointing towards the air inlet.

3. The fan according to claim 2, characterized in that, The centrifugal impeller includes a plurality of first blades arranged around the axis of the cone, and the plurality of first blades are spaced apart on the outer peripheral surface of the cone. The first blade extends at least partially along the axial and circumferential spiral of the cone, such that a compression channel with an axial extension component is formed between two adjacent first blades.

4. The fan according to claim 3, characterized in that, The compression channel is provided with a second blade for diverting the flow, the second blade extending from the middle region of the compression channel to the outlet end of the compression channel.

5. The fan according to claim 3, characterized in that, The air duct includes an air inlet section and an air outlet section. The wall profile of the air inlet section is adapted to the outer edge of a plurality of first blades. The air outlet section surrounds the outer periphery of the outlet end of the compression flow channel and has a guide surface for guiding the airflow to be discharged along the axial direction of the fan.

6. The fan according to claim 1, characterized in that, The axial flow impeller includes a hub and a plurality of third blades disposed on the outer periphery of the hub. The plurality of third blades are arranged at circumferential intervals along the hub to form an airflow channel with an axial extension component.

7. The fan according to claim 6, characterized in that, The third blade has a radial width of 5-20 mm in the hub and extends at an angle of 10-50° to the axis of the hub.

8. The fan according to claim 6, characterized in that, The flow guide includes an air outlet channel located downstream of the airflow channel and connected to the airflow channel. The air outlet channel is provided with a plurality of first guide vanes for guiding the airflow to flow along the axial direction of the fan. The plurality of first guide vanes are arranged at intervals along the circumference of the flow guide.

9. The fan according to claim 8, characterized in that, The first guide vane extends at an angle of 10 to 50° to the axis of the hub, and the first guide vane and the third vane are inclined in opposite directions relative to the axis of the hub.

10. The fan according to claim 1, characterized in that, A rectifier is provided between the centrifugal impeller and the axial impeller. The rectifier is located downstream of the air duct and upstream of the axial impeller. The rectifier is used to make the airflow discharged from the air duct flow along the axial direction of the fan to the axial impeller.

11. The fan according to claim 10, characterized in that, The rectifier includes a rectifier channel located downstream of the air duct and connected to the air duct. The rectifier channel is provided with a plurality of second guide vanes for guiding airflow along the axial direction of the fan. The plurality of second guide vanes are arranged at circumferential intervals along the rectifier.

12. The fan according to claim 1, characterized in that, The fan also includes a motor located downstream of the guide vane, the motor shaft being arranged along the axis of the fan, the centrifugal impeller and the axial impeller being connected to the shaft and rotating with the shaft; the airflow discharged from the guide vane blows at least part of it toward the motor body.

13. An electric device, characterized in that, Includes the wind turbine as described in any one of claims 1 to 12.

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