Fan and cleaning equipment

Abstract

The invention provides a fan and cleaning equipment, and belongs to the field of cleaning equipment. The fan comprises a movable impeller and a driving assembly. The movable impeller is provided with an air inlet pipe extending in the axial direction and blades arranged on the inner circumference of the rear section of the air inlet pipe. The driving assembly comprises a rotor arranged on the periphery of the front section of the air inlet pipe and a stator arranged on the periphery of the rotor, and the stator is used for providing an electromagnetic field for driving the rotor to rotate; when the rotor rotates, the air inlet pipe can be driven to rotate around the axis of the rotor, the air inlet pipe serves as a rotating shaft of a draught fan to drive the blades to do work on air, and therefore airflow which enters from the front section of the air inlet pipe and is exhausted from the rear section of the air inlet pipe is formed. According to the fan and the cleaning equipment, through the overall layout of the movable impeller and the driving assembly, the integrated design of the rotating shaft function and the air inlet channel is achieved, and vibration and structural noise can be reduced.

Description

TECHNICAL FIELD

[0001] The present disclosure belongs to the technical field of cleaning equipment, and particularly relates to a fan and a cleaning equipment. BACKGROUND

[0002] With the popularization of vacuum cleaners, the user's attention to product performance has gradually extended from the size of suction force and endurance time to the use comfort of the whole machine, and the noise level of the whole machine has become one of the important factors affecting the user experience. In the existing vacuum cleaner, the noise of the whole machine is usually composed of pneumatic noise and structural vibration noise, and as the core component of generating negative pressure and airflow, the vibration and noise characteristics of the fan determine the noise performance of the whole machine to a great extent.

[0003] When the fan rotates at high speed, on the one hand, the impeller does work on the air to produce strong pneumatic sound source; on the other hand, the unbalanced magnetic pull of the motor operation, the dynamic unbalance of the impeller itself and the shaft, bearing friction and other factors will cause violent mechanical vibration. These vibrations are transmitted to the whole machine through the motor support, the air duct shell and other connecting structures, exciting the resonance of large-area components such as the outer shell, thereby radiating wide-band structural noise from low frequency to medium-high frequency. Therefore, the vibration intensity of the fan and its coupling relationship with the structure of the whole machine are the core and difficulty of current vacuum cleaner noise control. SUMMARY

[0004] The purpose of the present disclosure is to provide a fan and a cleaning equipment which can improve the noise problem of the fan.

[0005] To achieve the above purpose, the technical solution provided by the present disclosure is as follows:

[0006] In a first aspect, the present disclosure provides a fan, which comprises a dynamic impeller and a driving assembly. The dynamic impeller has an air inlet pipe extending in the axial direction and blades arranged on the inner periphery of the rear section of the air inlet pipe. The driving assembly comprises a rotor arranged on the outer periphery of the front section of the air inlet pipe and a stator arranged on the outer periphery of the rotor, the stator being used to provide an electromagnetic field to drive the rotor to rotate. When the rotor rotates, it can drive the air inlet pipe to rotate around its axis, so that the air inlet pipe as the rotating shaft of the fan drives the blades to do work on the air, thereby forming an airflow entering from the front section of the air inlet pipe and being discharged from the rear section of the air inlet pipe. By letting the air inlet pipe serve as both an airflow passage and a fan rotating shaft, the equivalent diameter is increased, the critical speed is improved, the air inlet cross-sectional area is ensured, and a fan structure with small vibration, low noise and reliable pneumatic performance under high-speed working condition is realized.

[0007] In one or more embodiments, the rear section of the inlet pipe is provided with a flow guiding portion downstream of the rotor, the flow guiding portion having an outlet diameter gradually increasing in the air flow direction of the inlet pipe. The flow guiding portion with gradually increasing outlet diameter is arranged in the rear section of the inlet pipe to expand and diffuse the high speed air flow at the outlet of the blades smoothly towards the periphery, which is beneficial to pressure recovery, weakening of the strong jet flow and local vortex.

[0008] In one or more embodiments, the fan further comprises a stator ring stationary relative to the stator, the stator ring comprising a flow guiding portion penetrating through the blades and protruding into the inlet pipe, the blades being arranged around the periphery of the flow guiding portion, the flow guiding portion being configured to guide the air flow from the front section of the inlet pipe to pass through the blades from the periphery of the flow guiding portion. The flow guiding portion of the stator ring is arranged to distribute the air flow from the front section of the inlet pipe evenly to the inlets of the blades, to improve the uniformity of the flow field at the inlets of the blades, to improve the aerodynamic efficiency and to reduce the noise caused by the non-uniform air flow.

[0009] In one or more embodiments, the flow guiding portion comprises a tapered tip protruding upstream of the blades, the tapered tip having a diameter gradually increasing in the air flow direction of the inlet pipe. The tapered tip with gradually increasing diameter is arranged at the front end of the flow guiding portion to guide the air flow from the front section of the inlet pipe smoothly on the surface of the tip and to diffuse the air flow radially outward, thereby reducing the impact on the leading edge of the blades and reducing the separation and vortex.

[0010] In one or more embodiments, the flow guiding portion comprises a tail portion downstream of the rotor and adapted to the profile of the flow guiding portion, the tail portion and the flow guiding portion forming a flow guiding passage for guiding the air flow from the inlet pipe. The tail portion downstream of the flow guiding portion and adapted to the profile of the flow guiding portion is arranged to guide the air flow from the outlet of the blades smoothly to the external flow passage, which is beneficial to control the flow line shape during the expansion process, to reduce the flow separation and pressure pulsation.

[0011] In one or more embodiments, the stator ring further comprises a skirt portion extending axially from the periphery of the tail portion, the periphery of the skirt portion being provided with an annular flow passage extending axially and communicating with the flow guiding passage. The skirt portion extending axially from the tail portion and the annular flow passage at the periphery of the skirt portion are arranged to confine the air flow with strong radial velocity from the flow guiding passage in the annular passage extending axially, to weaken the radial jet component and to create a more stable air flow for the downstream flow regulation and noise reduction.

[0012] In one or more embodiments, the annular flow channel is provided with guide vanes for guiding the airflow to flow circumferentially along the annular flow channel. The guide vanes arranged in the annular flow channel guide the airflow to obtain a circumferential velocity component when passing through the annular flow channel, forming an airflow rotating downward in the axial direction and rotating in the circumferential direction, thereby reducing large-scale turbulent vortex and facilitating subsequent noise reduction.

[0013] In one or more embodiments, the annular flow channel is provided with an air outlet cover extending in the axial direction downstream of the annular flow channel, the air outlet cover comprising an inner shell and an outer shell surrounding the outer periphery of the inner shell, an air outlet flow channel in communication with the annular flow channel being formed between the inner shell and the outer shell, and a plurality of through-honeycomb holes being provided on the side walls of the inner shell and the outer shell. The through-honeycomb holes arranged on the side walls of the air outlet cover constitute a perforated honeycomb noise reduction structure, which can divide the airflow into a plurality of small-scale sub-flows, dissipate vortex and pressure pulsation during discharge, and effectively reduce the aerodynamic noise of the outlet section of the fan.

[0014] In one or more embodiments, the upstream of the air inlet pipe is provided with an air inlet cover for guiding external air into the fan, the air inlet cover being arranged around the outer periphery of the air inlet pipe, and a receiving space being formed between the air inlet cover and the air inlet pipe for accommodating the driving assembly. The air inlet cover arranged upstream of the air inlet pipe and the receiving space formed between the air inlet cover and the air inlet pipe accommodate the driving assembly, on the one hand, to organize the orderly entry of external air into the fan, and on the other hand, to provide a compact installation space for the driving assembly, facilitating integrated design with the air inlet flow path.

[0015] In one or more embodiments, the pipe wall of the air inlet pipe is provided with air inlet holes in communication with the receiving space, the air inlet holes being located downstream of the driving assembly and upstream of the blades. The air inlet holes arranged on the pipe wall of the air inlet pipe in communication with the receiving space are arranged downstream of the driving assembly and upstream of the blades, so that part of the low-temperature inlet air is first circulated around the driving assembly for heat dissipation before entering the air inlet pipe, which can effectively reduce the temperature rise of the stator and the winding and improve the thermal stability of the fan.

[0016] In a second aspect, the present disclosure provides a cleaning device comprising a cleaning head and the aforementioned fan, the fan being in communication with the cleaning head and being used to provide negative pressure to the cleaning head. The application of the aforementioned fan in the cleaning device makes the fan have low vibration, low noise, and good heat dissipation performance while providing stable negative pressure and sufficient suction, thereby improving the use comfort from the overall machine level.

[0017] The fan and the cleaning equipment provided by the present disclosure realize the integrated design of the rotating shaft function and the air inlet channel through the overall layout of the dynamic impeller and the driving assembly. The dynamic impeller adopts an air inlet pipe extending in the axial direction, and the air inlet pipe directly acts as the fan rotating shaft in structure. Compared with the traditional small-diameter solid rotating shaft, the outer diameter can be designed to be larger, the cross-sectional moment of inertia is significantly improved under the premise that the cross-sectional area of the air flow channel is not significantly compressed, and thus the bending stiffness and the critical speed of the rotating part are improved, the working speed of the fan is far away from the resonance zone, and vibration and structural noise can be reduced. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments described in the present disclosure, and other drawings can be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0019] Figure 1 It is a sectional view of the fan in an embodiment of the present disclosure.

[0020] Figure 2 It is a structural schematic view of the dynamic impeller in an embodiment of the present disclosure.

[0021] Figure 3 It is a structural schematic view of the static impeller in an embodiment of the present disclosure.

[0022] Figure 4 It is a structural schematic view of the air outlet cover in an embodiment of the present disclosure.

[0023] Main figure mark explanation:

[0024] 1-dynamic impeller, 11-air inlet pipe, 111-air inlet hole, 112-air inlet, 12-blade, 13-drainage part, 2-driving assembly, 21-rotor, 22-stator, 3-static impeller, 31-flow guide part, 311-conical tip, 312-tail part, 32-skirt part, 33-annular flow channel, 34-vane, 41-flow guide channel, 42-accommodation space, 5-air outlet cover, 51-inner shell, 52-outer shell, 53-air outlet flow channel, 54-honeycomb hole, 6-air inlet cover, 7-housing, 8-bearing. DETAILED DESCRIPTION

[0025] In order to make the person skilled in the art better understand the technical solutions in the present disclosure, the technical solutions in the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, rather than all the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by those of ordinary skill in the art without creative labor should fall within the scope of protection of the present disclosure.

[0026] Unless otherwise clearly indicated, in the entire specification and claims of the present disclosure, the term "comprise" or its variants such as "contain" or "include" and the like shall be understood to encompass the stated elements or components, without excluding other elements or components.

[0027] It should be noted that when an element is referred to as being "fixed" to another element, it can be directly on the other element or there can be an intervening element. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements can be present. In the embodiments of the present disclosure, the directional indications, i.e. up, down, left, right, front and back, etc. are relative, and are used to explain the structure and movement of different components in the present disclosure. These indications are appropriate when the components are in the positions shown in the drawings. However, if the positions of the components change, it is considered that these indications will also change accordingly.

[0028] The common dust collector fan currently uses a high-speed motor-driven centrifugal or mixed flow structure, and the moving impeller is generally connected to the motor rotor through a solid shaft. Under high-speed working conditions, the shaft will vibrate under the action of its own weight and aerodynamic force. When the rotational speed approaches the natural frequency of the transverse bending vibration of the shaft, it is easy to enter the critical speed region, causing resonance. At this time, the deflection of the shaft increases, the vibration of the moving impeller and the motor assembly is amplified and transmitted to the whole machine structure, resulting in a significant increase in fan vibration noise, and even affecting the bearing life and the reliability of the whole machine. Although the vibration problem can be improved to some extent by increasing the material elastic modulus and optimizing the support stiffness, in the limited installation space, the diameter of the solid shaft is difficult to increase significantly, and the bending stiffness of the shaft is limited, so there is still a prominent contradiction between the fan in high speed, small size and high negative pressure demand.

[0029] In addition, the existing dust collector fan mostly adopts the structure form that the motor and the dynamic impeller are coaxially arranged, the motor stator is usually located at the downstream side of the impeller, that is, in the high temperature area after the airflow is compressed and worked by the blade. Since the gas is accelerated and compressed when passing through the dynamic impeller, the temperature of the gas is increased, the high temperature airflow flows through the motor stator and winding for heat dissipation, and the cooling capacity is obviously limited. In the high power and small size fan, the stator core and winding itself generates a large amount of heat, when the cooling capacity of the high temperature gas is insufficient, the stator temperature rise is prone to be too high, the insulation system is accelerated to age, and the long-term stable operation of the fan and the whole machine is affected. Although the existing technology can alleviate the risk of temperature rise by increasing the air outlet section, increasing the flow guide structure or using higher temperature resistant grade materials, it usually brings problems such as structural complication, cost increase or aerodynamic performance decline.

[0030] In the analysis of the prior art, on the one hand, the traditional fan generally relies on a solid shaft with limited diameter to bear the impeller and torque transmission, and the shaft is easy to approach its bending natural frequency under high speed rotation, thereby inducing resonance, so that vibration and noise are significantly amplified. In the space-limited product such as the dust collector, it is difficult to simply increase the critical speed by thickening the solid shaft, because it will directly occupy the airflow channel, bring new contradictions such as increased flow resistance and decreased efficiency. On the other hand, the existing motor stator is often arranged near the high temperature air outlet area, and relies on the airflow heated by the impeller for heat dissipation. In high power working condition, the stator core and winding have insufficient heat dissipation margin, the temperature rise is too high, and the reliability is affected.

[0031] The critical speed (the speed of the shaft corresponding to the natural frequency of the transverse bending vibration of the shaft when the speed of the shaft reaches the natural frequency) is an important parameter for evaluating the dynamic stability of the fan shaft. When the speed of the shaft approaches or reaches the natural frequency of the transverse bending vibration of the shaft, the shaft will be obviously deflected under the action of centrifugal force, the bending amplitude will be rapidly amplified, and the shaft will enter the resonance state, thereby causing severe vibration of the shaft, and the vibration will be transmitted to the dynamic impeller, the rotor, the stator support and the whole machine shell, causing fan noise and structural fatigue problems.

[0032] For a rotor system composed of a shaft, a rotor, an impeller and a bearing support structure, the critical speed has a certain relationship with the material and structural parameters: wherein N is the critical speed of the shaft, E is the elastic modulus of the material of the shaft, I is the moment of inertia of the cross section of the shaft, m is the equivalent mass participating in vibration, and L is the equivalent span of the shaft under the constraint of the support. When the shaft is simplified as a circular cross section, the moment of inertia I and the diameter d of the shaft satisfy It can be seen that the moment of inertia I is highly sensitive to the diameter d of the shaft. Under the premise that the material and length are basically fixed, the moment of inertia I will be doubled with the increase of the diameter d, and then the critical speed N will be significantly increased.

[0033] That is, when the parameters E, m, L, etc. are certain, the critical speed N is positively correlated with the diameter d, the larger the diameter, the more difficult the shaft to approach its own bending natural frequency interval in the working speed range, the shaft deformation is inhibited, the impeller and the rotor are not easy to produce large amplitude swing, so as to obviously reduce the structural vibration and noise problem caused by resonance. In the design of fan structure, if only the slender solid shaft is used, under the constraint of limited installation space and air path, it is difficult to increase the diameter, resulting in small inertia moment and insufficient bending stiffness, and the critical speed is easy to fall near the target working speed of the fan, so that the whole machine appears vibration peak in high speed working condition, which is extremely unfavorable to the bearing life and noise control. Based on the above mechanical relationship, reasonably increasing the equivalent diameter of the shaft and improving the cross-sectional moment of inertia become the key design basis for improving the critical speed and improving the resonance noise performance of the fan.

[0034] Based on the above analysis, the technical implementation idea of the present disclosure adjusts the functional division and spatial layout of the fan as a whole. The present disclosure first reconstructs the relationship between the rotor and the impeller, and changes the solid shaft which is only used to transmit torque in the traditional sense into a hollow rotating member with rotating bearing and air inlet guide functions. The member obtains a larger equivalent rotating diameter and higher bending stiffness on the premise of maintaining sufficient air passage section, thereby lifting the critical speed at the structural level and reducing the deflection vibration at high speed. At the same time, by arranging the electromagnetic driving unit at the front end region of the rotating member, the driving force is directly applied to the hollow member body, realizing a compact transmission path.

[0035] Secondly, in terms of heat management, the present disclosure adjusts the relative position of the motor assembly and the air path and the organization mode of the inlet and outlet air flow, so that the motor heating elements are more exposed to the low-temperature inlet air side, and the relatively low-temperature air before entering the impeller is used to cool the motor heating elements. Through this arrangement idea, the original existing inlet air kinetic energy can be used to undertake the heat dissipation task without increasing additional air source and complex cooling mechanism, thereby improving the temperature rise environment of the stator core and winding.

[0036] Please refer to Figure 1 and Figure 2 The fan in an embodiment of the present disclosure includes a moving impeller 1 and a driving assembly 2. The moving impeller 1 has an air inlet pipe 11 extending in the axial direction, and a blade 12 arranged on the inner periphery of the rear section of the air inlet pipe 11. The driving assembly 2 includes a rotor 21 arranged on the outer periphery of the front section of the air inlet pipe 11, and a stator 22 arranged on the outer periphery of the rotor 21, the stator 22 being used to provide an electromagnetic field to drive the rotor 21 to rotate. When the rotor 21 rotates, it can drive the air inlet pipe 11 to rotate around its axis, so that the air inlet pipe 11 as the rotating shaft of the fan drives the blade 12 to do work on the air, thereby forming an air flow entering from the front section of the air inlet pipe 11 and being discharged from the rear section of the air inlet pipe 11.

[0037] The impeller 1 is mainly composed of an air inlet pipe 11 extending along the fan axis, the air inlet pipe 11 is a hollow cylinder structure as a whole, the front section is used for guiding the outside air to enter the inside of the air inlet pipe 11 along the axial direction, and the inner periphery of the rear section is fixedly installed with annularly distributed blades 12, the blades 12 extend to the center direction of the air inlet pipe 11 in the radial direction and are coaxially arranged with the air inlet pipe 11, so that a section of impeller working area for doing work on the air is formed around the rear section of the air inlet pipe 11.

[0038] The driving assembly 2 is arranged on the outer periphery of the front section of the air inlet pipe 11, the driving assembly 2 comprises a rotor 21 and a stator 22 arranged around the outer periphery of the rotor 21, the rotor 21 is fixedly connected with the front section of the air inlet pipe 11, and the two are integrally rotated around the fan axis, and the stator 22 is fixed on the static part through the shell 7 or the support structure, forming an inner rotor motor structure. The stator 22 generates an electromagnetic field after being electrified, the electromagnetic field drives the rotor 21 to rotate relative to the stator 22, since the rotor 21 is fixedly connected with the front section of the air inlet pipe 11, the torque is directly transmitted to the air inlet pipe 11, so that the air inlet pipe 11 as a whole rotates around the axis thereof, and the blades 12 on the inner periphery of the rear section of the air inlet pipe 11 are driven to do work on the air flowing therethrough under the rotation, so that the air is accelerated and pressurized, forming an air flow entering from the front section of the air inlet pipe 11, being accelerated in the working area of the blades 12 and finally being discharged from the rear section of the air inlet pipe 11.

[0039] Please refer to Figure 1 The outer periphery surface of the rear section of the air inlet pipe 11 and the inner wall of the fan shell 7 can be provided with a bearing 8, the bearing 8 is used as the main rotating support element of the air inlet pipe 11, the inner ring of the bearing 8 is tightly sleeved on the outer periphery surface of the rear section of the air inlet pipe 11, and the air inlet pipe 11 is integrally rotated through interference fit or other fixing modes, the outer ring of the bearing 8 is fixedly connected on the inner wall of the fan shell 7, and the fan shell 7 remains static. When the air inlet pipe 11 rotates at a high speed as the fan rotating shaft around the axis thereof, the radial load and part of the axial load generated by the rotating part can be effectively transmitted to the fan shell 7 by relying on the bearing 8, so that stable support is obtained in the radial direction. Through accurate positioning of the bearing 8, friction, interference and additional vibration caused by eccentricity or runout of the air inlet pipe 11 can be avoided, noise is reduced, and the service life of the whole machine is prolonged. Although not explicitly shown in the figure, the bearing 8 can be a ball bearing or the like.

[0040] In the foregoing fan structure, the air inlet pipe 11 no longer only serves as an air flow passage, but also bears the function of the fan rotating shaft. By replacing the traditional slender solid rotating shaft with the hollow cylindrical air inlet pipe 11 (the air inlet pipe 11 acts as the fan rotating shaft), the rotating member obtains a larger outer diameter under the premise of maintaining a sufficient air inlet passage cross-sectional area, and the moment of inertia of the hollow cylindrical section is significantly improved, so that the rotating member is superior to the small-diameter solid shaft in terms of bending stiffness and critical speed.

[0041] When the material, length and installation conditions are approximately equivalent, the increase of the diameter of the air inlet pipe 11 can effectively raise the critical speed, so that the normal working speed of the fan is far away from the bending inherent frequency interval of the rotating shaft, thereby reducing the deflection vibration caused by approaching or crossing the critical speed, and facilitating the reduction of structural vibration noise and the improvement of the running stability of the whole machine. Meanwhile, the hollow structure forms a continuous air inlet passage inside, compared with the scheme of thick solid rotating shaft, it does not need to be additionally wound around the complex air path of the thick solid rotating shaft, from the perspective of space utilization and aerodynamic efficiency, the hollow air inlet pipe 11 realizes the consideration of structural stiffness and flow passage section.

[0042] The outer periphery of the front section of the air inlet pipe 11 is surrounded by the rotor 21, and the outer periphery of the rotor 21 is surrounded by the stator 22. The driving assembly 2 is arranged in the air inlet side area as a whole, and the blades 12 are arranged in the rear section of the air inlet pipe 11. Such front and rear partition arrangement makes the driving assembly 2 in the relatively low-temperature air inlet area, and the high-temperature gas generated after the blades 12 do work is mainly located in the rear section of the air inlet pipe 11 and downstream thereof. After the airflow is sucked from the front section of the air inlet pipe 11, it first passes through the area close to the driving assembly 2, and then continues to flow downstream to the position of the blades 12, and obtains speed and pressure under the pushing of the blades 12. Finally, it is discharged from the rear section of the air inlet pipe 11 and will not flow back through the driving assembly 2 in structure. That is to say, the low-temperature air inlet is mainly around the driving assembly 2, and the high-temperature air outlet is limited to the downstream area of the blades 12, which avoids the long-time flushing of the motor stator 22 and rotor 21 by high-temperature gas from the flow path, and is beneficial to control the working temperature of the stator 22 core and winding, improve the heat dissipation condition of the motor part, slow down the insulation aging and performance attenuation.

[0043] In an exemplary embodiment, please refer to Figure 1 and Figure 2 It is shown that the rear section of the air inlet pipe 11 is provided with a flow guide part 13 located downstream of the moving vane 1. The caliber of the flow guide part 13 gradually increases along the air outlet direction of the air inlet pipe 11.

[0044] The rear section of the air inlet pipe 11 is integrally formed as a flow guide part 13 for guiding the outlet airflow of the blades 12. The flow guide part 13 is preferably coaxial with the air inlet pipe 11 and is located in the downstream area of the moving vane 1. The caliber of the flow guide part 13 gradually increases along the air outlet direction of the air inlet pipe 11, and the inner wall profile smoothly transitions from the smaller diameter at the front end to the larger diameter at the rear end, so that the flow guide part 13 forms a channel shape similar to a horn mouth in the axial direction.

[0045] The blades 12 on the inner circumference of the rear section of the inlet duct 11 perform work on the airflow when rotating, accelerating the airflow and giving it a certain rotational velocity component. The airflow velocity and dynamic pressure at the outlet section of the blades 12 are relatively high. If it directly enters the downstream flow channel, it is easy to form a strong jet and local vortex, which is not conducive to pressure recovery and noise control. By arranging the guide section 13 immediately downstream of the blades 12 and adopting a structure with a gradually increasing diameter, the high-speed airflow at the outlet of the blades 12 diffuses outward along the expanding inner wall after entering the guide section 13. The axial velocity gradually decreases, and part of the dynamic pressure is gently converted into static pressure, thereby achieving pressure diffusion and flow stabilization.

[0046] Preferably, the front end of the guide section 13 is closely connected to the rear section of the air inlet pipe 11 where the blades 12 are arranged, without any obvious steps or structural abrupt changes, ensuring the streamline continuity between the outlet section of the blades 12 and the inlet section of the guide section 13, and reducing the risk of separation and boundary layer peeling; the rear end of the guide section 13 faces the downstream air passage of the entire fan, and is connected to the subsequent guide structure or air outlet channel, providing the downstream air passage with an inlet boundary condition with a larger cross section and more uniform flow velocity.

[0047] In one exemplary embodiment, please refer to Figure 1 and Figure 3 As shown, the fan also includes a stationary impeller 3 relative to the stator 22. The impeller 3 includes a guide section 31 that passes through the blades 12 and protrudes into the air inlet pipe 11. The blades 12 surround the outer periphery of the guide section 31. The guide section 31 is used to allow the airflow entering from the front section of the air inlet pipe 11 to pass through the blades 12 from the outer periphery of the guide section 31.

[0048] In addition to the moving impeller 1 and the drive assembly 2, the fan also includes a stationary fixed impeller 3 that remains relatively stationary with respect to the stator 22. The stationary impeller 3 is fixed to the fan casing 7 by a support structure and does not participate in rotation during fan operation. The core component of the stationary impeller 3 is the guide section 31, which extends along the fan axial direction. A portion of the guide section 31 passes through the blade 12 area of ​​the moving impeller 1 and protrudes into the inlet pipe 11. Preferably, the axis of the guide section 31 coincides with the axis of the inlet pipe 11, forming an annular space between the outer periphery of the guide section 31 and the inner wall of the inlet pipe 11. The blades 12 on the inner periphery of the rear section of the inlet pipe 11 circumferentially surround the outer periphery of the guide section 31. Through this structural relationship, an annular space with a cross-section is formed between the guide section 31 and the inlet pipe 11, and the airflow is confined within this annular space before entering the blades 12.

[0049] When the fan is running, the air flow entering from the front section of the air inlet pipe 11 first moves downstream in the axial direction of the air inlet pipe 11. When the air flow passes through the area where the guide portion 31 is located, the guide portion 31 divides and guides the air flow with the front edge, so that the air flow is uniformly distributed to the entire circumferential direction along the outer periphery of the guide portion 31, avoiding the air flow from directly impacting part of the blades 12 in a local area. Since the guide portion 31 is arranged substantially coaxially with the air inlet pipe 11, the annular space between the outer periphery of the guide portion 31 and the inner wall of the air inlet pipe 11 is uniformly distributed in the circumferential direction. After the air flow flows into the annular space from the front section, the air flow tends to be uniformly diffused in the circumferential direction, and then passes through the gap between the blades 12 from the outer periphery of the guide portion 31 to enter the working area of the blades 12, so that each blade 12 obtains a relatively consistent incoming flow condition at the inlet, reduces the unevenness of one-sided incoming flow and bias flow, and is beneficial to improve the aerodynamic efficiency of the entire impeller 1 and reduce the separation of boundary layer and vortex noise caused by uneven incoming flow.

[0050] Specifically, referring to Figure 1 and Figure 3 , the guide portion 31 includes a tapered tip portion 311 protruding upstream of the blades 12, and the diameter of the tip portion gradually increases in the air outlet direction of the air inlet pipe 11.

[0051] The front end of the guide portion 31 forms an integral tapered tip portion 311, which extends forward in the fan axis direction, and the front end is located in the upstream area of the blades 12 and extends into the incoming flow area inside the air inlet pipe 11. The tapered tip portion 311 is coaxially arranged with the axis of the air inlet pipe 11 as a whole, and the outer contour gradually transitions from a smaller diameter near the front section of the air inlet pipe 11 to a larger diameter in the air outlet direction of the air inlet pipe 11, forming a continuous and smooth conical curved surface. The air flow sucked into the front section of the air inlet pipe 11 originally flows downstream in a nearly axial manner, and when it encounters the tapered tip portion 311 located upstream of the blades 12, it is divided by the front edge of the tapered tip portion 311 and slides along the outer surface of the tapered tip portion 311. When the air flow passes through the tapered tip portion 311, part of the kinetic energy is converted into radial distribution around the outer periphery of the tip portion, so that the air flow is pushed to the blades 12 in the axial direction while gradually diffusing along the radial outside.

[0052] Further, referring to Figure 1 and Figure 3 , the guide portion 31 includes a tail portion 312 located downstream of the impeller 1 and matched with the profile of the flow guide portion 13, and a guide passage 41 is formed between the tail portion 312 and the flow guide portion 13 for guiding the air flow out of the air inlet pipe 11.

[0053] The guide flow part 31 forms a tail part 312 at a position close to the downstream of the rotor 1, the tail part 312 is arranged opposite to the guide part 13 as a whole and matches the guide part 13 in profile line. With the axis of the inlet pipe 11 as a common reference, the tail part 312 and the guide part 13 are preferably coaxially arranged, and a predetermined gap is kept in the radial direction, so that a guide flow channel 41 extending in the axial and radial directions is enclosed between the tail part 312 and the guide part 13.

[0054] When the rotor 1 is in operation, the blade 12 does work on the airflow in the inlet pipe 11, and after passing through the blade 12 and entering the area of the guide part 13, the airflow is first guided to diffuse downstream along the inner wall of the guide part 13, and then reaches the gap area between the guide part 13 and the tail part 312. Since the outer profile of the tail part 312 and the inner profile of the guide part 13 are matched in curve shape and expansion trend, the channel section of the guide flow channel 41 can present continuous and smooth changes in the axial direction, without sudden contraction or expansion steps, so that the airflow maintains a relatively smooth streamline shape when passing through the guide flow channel 41.

[0055] The guide part 13 undertakes the primary pressure expansion and external expansion guiding of the high-speed airflow at the outlet of the blade 12, and the tail part 312 cooperates with the guide part 13 to jointly complete the task of smoothly guiding the airflow out of the inside of the inlet pipe 11. The guide flow channel 41 formed between the two parts limits the flow range of the airflow, avoids the high-energy airflow downstream of the blade 12 from directly escaping in disorder in the fan inner space, and reduces the generation of large-scale vortex and backflow area. On the other hand, by controlling the opening change of the guide flow channel 41 in the axial direction, the airflow gradually completes the conversion of dynamic pressure to static pressure in the channel, reduces the local flow velocity and pressure pulsation, and provides more uniform and stable inlet boundary conditions for the subsequent annular flow passage 33 or the air outlet cover 5.

[0056] In an exemplary embodiment, referring to Figure 1 and Figure 3 , the stator wheel 3 further includes a skirt part 32 extending in the axial direction from the peripheral edge of the tail part 312, and the outer periphery of the skirt part 32 is provided with an annular flow passage 33 in communication with the guide flow channel 41 and extending in the axial direction.

[0057] The skirt part 32 extends in the downstream direction of the fan axial direction from the outer edge of the tail part 312, and is coaxially arranged with the axis of the inlet pipe 11 as a whole, and the outer side surface thereof continuously connects with the outer profile of the tail part 312 in the axial direction, and faces the fan housing 7 or other positioning structure. A certain gap is reserved between the outer periphery of the skirt part 32 and the fan housing 7 or the positioning structure, the gap is closed in the annular direction and extends in the axial direction, so that an annular flow passage 33 in communication with the guide flow channel 41 is formed around the outer periphery of the skirt part 32.

[0058] The air flow at the outlet of the blade 12 not only maintains a high axial velocity component when passing through the guide passage 41, but also diffuses to the radial outside during the diffuser process, thereby obtaining a radial velocity component in the guide passage 41. If the air flow directly enters the downstream flow passage after obtaining a large radial velocity, a strong radial jet and backflow vortex is easily formed in the shell 7, which is not conducive to pressure recovery and noise control.

[0059] By continuously extending the skirt 32 at the end of the tail 312 and forming an annular flow passage 33 extending in the axial direction by the outer periphery of the skirt 32 and the adjacent structure, a constrained axial guide section of the air flow can be provided after the guide passage 41. When the air flow flows out of the guide passage 41 and enters the annular flow passage 33, the radial flow space is limited by the annular flow passage 33, and the originally strong radial velocity component is gradually weakened in the annular flow passage 33, and the flow direction is reorganized to mainly axial velocity component.

[0060] Specifically, referring to Figure 1 and Figure 3 , the annular flow passage 33 is provided with guide vanes 34 for guiding the air flow to flow circumferentially along the annular flow passage 33. The guide vanes 34 are arranged circumferentially along the annular flow passage 33 and are fixedly connected to the inner wall or outer wall of the annular flow passage 33. The guide vanes 34 extend in the axial direction of the annular flow passage 33 in the spanwise direction, and the plane thereof forms a predetermined angle with respect to the circumferential tangent and the axis of the annular flow passage 33, thereby structurally forming a set of three-dimensional guide vanes that guide the air flow.

[0061] The air flow entering the annular flow passage 33 from the guide passage 41 has a weakened radial velocity component under the action of the previous stage structure, and mainly flows in the axial direction in the annular flow passage 33. When the air flow passes through the surface of the guide vane 34, the originally axial flow is deflected by a portion of the velocity component to the circumferential direction under the combined action of the installation angle and curvature of the guide vane 34, so that the air flow obtains a circumferential velocity component while being transported downstream in the axial direction.

[0062] By designing the number, circumferential spacing and installation angle of the guide vanes 34, the air flow in each region of the annular flow passage 33 can form similar rotation intensity under the action of the guide vanes 34, avoiding local excessive rotation or insufficient rotation, so as to obtain a rotating air flow with superimposed axial velocity and circumferential velocity at the outlet of the annular flow passage 33. The rotating air flow flows downstream in the axial direction of the fan as a whole, which is beneficial to the smooth transmission of momentum in the subsequent air outlet cover 5 or downstream pipeline, reduces the generation of secondary vortex and irregular large-scale vortex, and reduces the aerodynamic noise. On the other hand, the appropriate circumferential velocity component can improve the pressure recovery characteristics of the downstream diffusion section, so that the energy conversion process is smoother, and the aerodynamic efficiency and operating stability of the fan flow passage are improved as a whole.

[0063] In an exemplary embodiment, referring to Figure 1and Figure 4 As shown, the downstream of the annular flow passage 33 is provided with an air outlet cover 5 extending in the axial direction, the air outlet cover 5 comprises an inner shell 51 and an outer shell 52 surrounding the outer periphery of the inner shell 51, and the inner shell 51 and the outer shell 52 form an air outlet flow passage 53 in communication with the annular flow passage 33, and a plurality of honeycomb holes 54 are arranged on the side walls of the inner shell 51 and the outer shell 52.

[0064] The air outlet cover 5 is preferably coaxially arranged with the annular flow passage 33, comprising the inner shell 51 located in the middle and the outer shell 52 surrounding the outer periphery of the inner shell 51, and the annular air outlet flow passage 53 is formed between the inner shell 51 and the outer shell 52 by radial spacing, and the air outlet flow passage 53 is in communication with the annular flow passage 33 in the axial direction, so that the airflow guided through the annular flow passage 33 smoothly transitions into the air outlet flow passage 53 without significant turning and steering.

[0065] A plurality of honeycomb holes 54 are arranged on the side walls of the inner shell 51 and the outer shell 52, and the honeycomb holes 54 are arrayed in the circumferential and axial directions. Specifically, the honeycomb holes 54 pass through the shell walls in the radial direction of the inner shell 51 and the outer shell 52, and are uniformly arranged at substantially equal intervals in the circumferential direction of the inner shell 51 and the outer shell 52, and in the circumferential cross-section perpendicular to the axis, the honeycomb holes 54 form a ring of hole columns around the axis of the inner shell 51 and the outer shell 52. In the axial direction, several rings of the aforementioned hole columns can be arranged on the side walls of the inner shell 51 and the outer shell 52, and the adjacent two rings of hole columns are kept at a predetermined interval in the axial direction, so that the plurality of honeycomb holes 54 are arrayed in the circumferential and axial directions of the inner shell 51 and the outer shell 52.

[0066] Each honeycomb hole 54 approximately constitutes an elongated small passage, and the plurality of honeycomb holes 54 collectively form a perforated honeycomb noise reduction structure. After the airflow guided by the annular flow passage 33 enters the air outlet flow passage 53, it flows in the axial direction within the air outlet flow passage 53 and maintains the rotational characteristics imparted by the guide vanes 34 to some extent, and then the airflow is divided into several sub-flows, which are sequentially discharged through the honeycomb holes 54 distributed on the side walls of the inner shell 51 and the outer shell 52.

[0067] When the airflow passes through the honeycomb holes 54, viscous shear and turbulent dissipation occur between the airflow and the hole walls, large-scale vortices can be refined and attenuated step by step, thereby effectively weakening the pressure pulsation caused by unstable flow. At the same time, the perforated wall formed by the honeycomb holes 54 behaves acoustically as a kind of acoustic element with impedance characteristics, which has filtering and attenuating effects on noise of specific frequency bands, so that the mid-high frequency aerodynamic noise of the fan outlet section is significantly reduced, and the noise characteristics and flow field stability of the fan outlet section are improved while maintaining a certain air outlet capacity.

[0068] In an exemplary embodiment, please refer to Figure 1As shown, the upstream of the air inlet pipe 11 is provided with an air inlet cover 6 for guiding the outside air into the fan, the air inlet cover 6 is arranged on the outer periphery of the air inlet pipe 11, and the air inlet cover 6 and the air inlet pipe 11 form a receiving space 42 for accommodating the driving assembly 2.

[0069] The air inlet cover 6 is arranged at the upstream position of the air inlet pipe 11, the air inlet cover 6 is arranged on the outer periphery of the air inlet pipe 11 as a whole, and is preferably coaxially arranged with the air inlet pipe 11, and the two form a ring-shaped receiving space 42 through the reserved gap in the radial direction, which is used to accommodate the driving assembly 2, so that the driving assembly 2 is in the area washed by the inlet air flow when the fan is working. The air inlet cover 6 can be fixed on the fan shell 7 or other positioning structure, and the front end opening faces the external environment, which is used to collect the outside air and guide the air into the fan in the axial direction; the rear end is connected with the fan shell 7 through the transition section, which forms a circle of covering protection for the front section of the air inlet pipe 11 and the driving assembly 2 in structure, so that the driving assembly 2 obtains mechanical support and shielding.

[0070] The receiving space 42 formed between the air inlet cover 6 and the air inlet pipe 11 not only serves as the installation cavity of the driving assembly 2, but also constitutes part of the fan air inlet path. When the fan is running, the outside air can enter the receiving space 42 through the front end opening of the air inlet cover 6, and flow around the driving assembly 2 in the space, on one hand, the air flow is sucked into the air inlet channel through the front end of the air inlet pipe 11 for the air working of the impeller 1, on the other hand, the air flow produces heat exchange effect on the rotor 21 and the stator 22 when flowing through the surface of the driving assembly 2, which carries away the heat generated in the working process of the driving assembly 2, thereby being beneficial to control the temperature rise of the core and winding of the stator 22.

[0071] Specifically, referring to Figure 1 and Figure 2 As shown, the pipe wall of the air inlet pipe 11 is provided with air inlet holes 111 communicating with the receiving space 42, the air inlet holes 111 are located downstream of the driving assembly 2 and upstream of the blade 12.

[0072] The pipe wall of the air inlet pipe 11 is provided with a plurality of air inlet holes 111, the air inlet holes 111 communicate with the receiving space 42 formed between the air inlet cover 6 and the air inlet pipe 11, and can be uniformly distributed in the ring direction and located in the downstream region of the driving assembly 2 and the upstream region of the blade 12 as a whole in the axial position. After such arrangement, the receiving space 42 and the inner cavity of the air inlet pipe 11 establish a communication channel through the air inlet holes 111, so that the air flowing around the driving assembly 2 can be introduced into the inside of the air inlet pipe 11.

[0073] When the fan is working, the outside air enters the fan through the front end opening of the air inlet cover 6, part of the air is sucked into the air inlet pipe 11 from the air inlet 112 at the front end of the air inlet pipe 11, and flows to the blade 12 in the axial direction to form a main flow passage; the other part of the air flows around the driving assembly 2 in the containing space 42, flows along the surface of the rotor 21 and the stator 22, and exchanges heat with the driving assembly 2 in a counterflow manner. After absorbing the heat generated by the driving assembly 2 during work, the air is guided into the inner cavity of the air inlet pipe 11 through the air inlet hole 111, and is combined with the air entering through the air inlet 112 in the upstream region of the blade 12.

[0074] Since the driving assembly 2 and the air inlet hole 111 are arranged upstream of the blade 12, the driving assembly 2 is in contact with low-temperature air that has not yet been compressed and worked by the blade 12, so that the driving assembly 2 is exposed to a lower-temperature airflow environment, thereby ensuring that there is a continuous cooling airflow around the stator 22 core and winding, and avoiding high-temperature outflow from backwashing the motor elements. Compared with the traditional structure in which the stator 22 is arranged downstream of the blade 12 and cooled by high-temperature outflow, the arrangement of the air inlet hole 111 communicating with the upstream containing space 42 can fully utilize the original air inlet process to efficiently cool the driving assembly 2 without adding an independent cooling air path, thereby reducing the temperature rise of the stator 22 and its winding, and improving the thermal stability of the fan under high-power and high-speed working conditions.

[0075] The present disclosure also provides a cleaning device comprising a cleaning head and the aforementioned fan, which is in communication with the cleaning head and used to provide negative pressure to the cleaning head.

[0076] The cleaning device comprises a cleaning head for cleaning a surface to be cleaned and a fan arranged in the body, which is in communication with the cleaning head through an air path and provides stable negative pressure to the cleaning head during operation. The cleaning head can be arranged at the front end or lower part of the cleaning device, forming a relatively sealed working area with the ground, carpet or other surface to be cleaned. An air inlet for sucking dust and debris is formed on the cleaning head, and the air inlet is connected to the air inlet side of the fan through an internal air duct, so that the fan can suck the air and the dirt carried by the air in the cleaning area when generating negative pressure.

[0077] The fan is preferably arranged near the center of gravity of the cleaning device body, and a continuous airflow channel is established between the fan and the cleaning head through a connecting pipeline. Dust-gas separation components or filter components can be connected in series in the body as needed to separate and filter particulate matter in the airflow, and finally the purified air is discharged to the outside of the device. The cleaning head serves as a front-end execution function for adhering to the surface to be cleaned and collecting dirt, and the fan serves as the airflow power source of the entire machine, which forms an airflow passage from the cleaning head to the fan through the cooperation of the impeller and the driving assembly.

[0078] In summary, the fan and cleaning equipment provided by the present disclosure realizes the integrated design of the rotating shaft function and the air inlet channel through the overall layout of the moving impeller and the driving assembly. The moving impeller adopts an air inlet pipe extending in the axial direction, and the air inlet pipe directly acts as the fan rotating shaft in structure. Compared with the traditional small-diameter solid rotating shaft, the outer diameter can be designed to be larger, the cross-sectional moment of inertia is significantly improved under the premise of not significantly compressing the cross-sectional area of the airflow channel, thereby improving the bending stiffness and critical speed of the rotating part, making the fan working speed far away from the resonance zone, and reducing vibration and structural noise.

[0079] It is apparent to those skilled in the art that the present disclosure is not limited to the details of the foregoing exemplary embodiments, and that the present disclosure can be implemented in other specific forms without departing from the spirit or essential characteristics of the present disclosure. Therefore, the embodiments should be considered in all respects as illustrative and not restrictive, and the scope of the present disclosure should be defined by the appended claims rather than the above description, and it is intended to include all changes falling within the meaning and scope of the equivalent elements of the claims. Any reference signs in the claims should not be considered as limiting the claims involved.

[0080] In addition, it should be understood that, although the present specification is described in terms of embodiments, not every embodiment contains only one independent technical solution, and the description of the specification is only for the sake of clarity, and those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can be appropriately combined to form other embodiments that those skilled in the art can understand.

Claims

1. A fan, characterized by, The fan comprises: a rotor, which is arranged at the outer periphery of the front section of the air inlet pipe and is used to provide an electromagnetic field for driving the rotation of the rotor; wherein the rotation of the rotor can drive the rotation of the air inlet pipe around its axis, so that the air inlet pipe, as the rotating shaft of the fan, drives the blades to work on the air, thereby forming the air flow that enters the front section of the air inlet pipe and is discharged from the rear section of the air inlet pipe. The rear section of the air inlet pipe is provided with a flow guide part located downstream of the rotor, and the caliber of the flow guide part gradually increases in the air outlet direction of the air inlet pipe.

2. The fan of claim 1, wherein The fan further comprises a stator wheel that is static relative to the stator, and the stator wheel comprises a flow guide part that penetrates through the blades and protrudes into the air inlet pipe, the blades are arranged around the outer periphery of the flow guide part, and the flow guide part is used to make the air flow that enters the front section of the air inlet pipe pass through the blades from the outer periphery of the flow guide part.

3. The fan of claim 2, wherein, The flow guide part comprises a tapered tip that protrudes upstream of the blades, and the diameter of the tapered tip gradually increases in the air outlet direction of the air inlet pipe.

4. The fan of claim 3, wherein, The flow guide part comprises a tail part located downstream of the rotor and matched with the profile of the flow guide part, and a flow guide channel is formed between the tail part and the flow guide part for guiding the air flow out of the air inlet pipe.

5. The fan of claim 3, wherein The stator wheel further comprises a skirt part that extends axially from the end periphery of the tail part, and the outer periphery of the skirt part is provided with an annular flow channel that communicates with the flow guide channel and extends axially.

6. The fan of claim 5, wherein, The annular flow channel is provided with guide vanes for guiding the air flow to flow circumferentially along the annular flow channel.

7. The fan of claim 6, wherein, The downstream of the annular flow channel is provided with an air outlet cover that extends axially, and the air outlet cover comprises an inner shell and an outer shell that is arranged around the outer periphery of the inner shell, a flow outlet channel that communicates with the annular flow channel is formed between the inner shell and the outer shell, and a plurality of honeycomb holes are arranged on the side walls of the inner shell and the outer shell.

8. The fan of claim 6, wherein, The upstream of the air inlet pipe is provided with an air inlet cover for guiding the external air to enter the fan, the air inlet cover is arranged around the outer periphery of the air inlet pipe, and a receiving space for accommodating the driving assembly is formed between the air inlet cover and the air inlet pipe.

9. The fan of claim 1, wherein The pipe wall of the air inlet pipe is provided with an air inlet hole that communicates with the receiving space, and the air inlet hole is located downstream of the driving assembly and upstream of the blades.

10. The fan of claim 9, wherein, The fan comprises a cleaning head and the fan of any one of claims 1 to 10, and the fan communicates with the cleaning head and is used to provide negative pressure to the cleaning head.

11. A cleaning apparatus, characterized by ​

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