Blade assembly, centrifugal fan and air conditioner

Abstract

The invention provides a blade assembly, a centrifugal fan and an air conditioner, the blade assembly is applied to the centrifugal fan, the blade assembly comprises a hub and fan blades fixed to the outer edge of the hub, the face, provided with the fan blades, of the hub is a windward face, a turbulent flow disc is arranged on the windward face, and the turbulent flow disc is connected with the hub. The turbulent flow disc is arranged on the windward side in a rotatable mode, airflow entering the centrifugal fan can blow the turbulent flow disc to swing, and therefore the technical problem that in the prior art, noise is large when a centrifugal fan blows air can be solved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of centrifugal fan, and particularly relates to a blade assembly, a centrifugal fan and an air conditioner. BACKGROUND

[0002] The existing fresh air conditioner mostly adopts a centrifugal fan system as a core of air supply. Although high-speed operation of the centrifugal fan system can ensure a large air volume, it is accompanied by problems such as loud noise and obvious wind noise, which affect the user experience. Therefore, there is an urgent need for a fresh air supply scheme with optimized structure and lower noise to improve the comfort and practicality of the fresh air conditioner. SUMMARY

[0003] Therefore, the present application provides a blade assembly, a centrifugal fan and an air conditioner, which can solve the technical problem of loud noise when the centrifugal fan blows air in the prior art.

[0004] In a first aspect, the present application provides a blade assembly applied to a centrifugal fan, which comprises a hub and an air blade fixed on the outer edge of the hub. One side of the hub on which the air blade is arranged is a windward surface, and a spoiler disc is arranged on the windward surface. The spoiler disc is rotatably arranged on the windward surface, and airflow entering the centrifugal fan can swing the spoiler disc.

[0005] In some embodiments, the rotation center of the hub is provided with a rotation damper, and the spoiler disc is connected to the hub through the rotation damper.

[0006] In some embodiments, the rotation damper is a “spring-friction combination” damper.

[0007] In some embodiments, the spoiler disc is disc-shaped, and the spoiler disc is concentrically arranged with the hub. A through hole is arranged on the spoiler disc.

[0008] In some embodiments, in the projection in the axial direction, the through hole is a regular hexagonal hole.

[0009] In some embodiments, a clearance slot is arranged on the spoiler disc, and the air blade passes through the clearance slot. When the hub remains stationary, the spoiler disc makes the air blade form a gap with the clearance slot under the action of the rotation damper.

[0010] In some embodiments, the edge of the hub is provided with a ring groove surrounding the hub, and the edge of the spoiler disc is provided with a ring plate protruding towards the hub. The ring plate is clamped into the ring groove and can rotate around the center of the hub in the ring groove.

[0011] In some embodiments, in the projection in the axial direction of the hub, the shape of the clearance slot is the same as the shape of the air blade.

[0012] In some embodiments, the middle part of the spoiler disc is away from the hub to form a protruding part.

[0013] In some embodiments, the side of the spoiler disc away from the hub is provided with flow guide grooves extending along the radial direction of the spoiler disc, and when the clearance grooves are provided, the end of the flow guide grooves close to the outer edge of the spoiler disc is located between two adjacent clearance grooves.

[0014] The second aspect of the present application provides a centrifugal fan, comprising a volute and the blade assembly.

[0015] The third aspect of the present application further provides an air conditioner, comprising the centrifugal fan.

[0016] The present application sets the spoiler disc on the windward side of the hub, the spoiler disc disturbs the airflow entering the volute, so that the airflow can flow uniformly, thereby reducing the flow noise of the airflow. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the following embodiment or prior art description will be briefly introduced. The drawings in the following description are only exemplary, and those skilled in the art can also obtain other implementation drawings according to the provided drawings without creative labor.

[0018] Figure 1 is a blade assembly schematic diagram of an embodiment of the present application;

[0019] Figure 2 is a spoiler disc schematic diagram of an embodiment of the present application;

[0020] Figure 3 is an axial schematic diagram of the spoiler disc of an embodiment of the present application;

[0021] Figure 4 is a radial schematic diagram of the spoiler disc of an embodiment of the present application;

[0022] Figure 5 is a schematic diagram of the fan blade when arranged on the hub of an embodiment of the present application;

[0023] Figure 6 is a schematic diagram of the centrifugal fan after removing the spoiler disc of an embodiment of the present application;

[0024] Figure 7 is a schematic diagram of the centrifugal fan when provided with the spoiler disc of an embodiment of the present application;

[0025] Figure 8 is a schematic diagram of the frame structure and filter screen structure of an embodiment of the present application;

[0026] Figure 9 is an appearance view of a centrifugal fan provided with an air inlet part according to an embodiment of the present application;

[0027] Figure 10 is a longitudinal coordinate and horizontal coordinate schematic view of a spoiler disc according to an embodiment of the present application.

[0028] Reference signs are:

[0029] 1, hub; 2, fan blade; 3, spoiler disc; 301, through hole; 302, accommodation slot; 303, protruding part; 4, rotation damper; 501, frame structure; 502, filter screen structure; 6, volute. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. The description of the at least one exemplary embodiment is actually only illustrative, but not as any limitation on the present application and its application or use. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work, fall within the scope of protection of the present application.

[0031] In the description of the present application, it should be understood that the orientation words such as "front, back, up, down, left, right", "transverse, vertical, perpendicular, horizontal" and "top, bottom" and the like indicate the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, without the opposite description, these orientation words do not indicate and imply that the indicated device or element must have a specific orientation or be constructed and operated in a specific orientation, therefore, it cannot be understood as a limitation on the scope of protection of the present application; the orientation words "inner, outer" refer to the inner and outer relative to the contour of each part itself.

[0032] For the purposes of the description, reference can be made to spatially relative terms such as "on", "above", "over", "top", "up", "down", "bottom", "under", "below", "side", "lower", "upper", "horizontal", "vertical", "above", "below", "upward", "downward", and the like, to describe the relative location and orientation of a device or feature in relation to another device or feature as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientations depicted in the figures. For example, if a device in the figures is inverted, then a device described as "above" or "over" another device or structure would now be positioned "below" or "under" the other device or structure. Thus, the exemplary term "above" can encompass both an orientation of above and below. The devices can be oriented in other ways (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly. The devices can be oriented in other ways (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

[0033] In addition, it should be noted that the use of "first", "second", and the like words of distinction do not have a special meaning, and are only used to distinguish corresponding parts, and therefore cannot be understood as a limitation on the scope of protection of the present application.

[0034] With the popularity of household air conditioners, indoor air quality problems are increasingly concerned. The traditional air conditioner only circulates indoor air for cooling or heating during operation, and lacks the introduction of fresh air, resulting in an increase in indoor carbon dioxide concentration and humidity imbalance, which can easily cause respiratory diseases and other health problems in long-term use. To solve this problem, fresh air air conditioners have emerged, which introduce fresh air from the outside to exchange indoor and outdoor air, effectively improving indoor air quality. For fresh air mechanisms, the noise source is relatively complex. From the air inlet end, fresh air needs to be introduced through the pipeline total outdoor unit, harmful substances in the fresh air are filtered out through the filter screen, and then the centrifugal impeller sends it into the main air duct or a separate fresh air duct. The fresh air path is relatively long and faces a large resistance. To achieve the required fresh air flow, the centrifugal impeller rotates at a high speed. Although the high-speed operation of the centrifugal fan system can ensure a large air flow, it is accompanied by problems such as high noise and obvious wind noise, which affect the user experience.

[0035] To reduce the noise of the fresh air conditioner when sending fresh air, the present application provides a blade assembly, a centrifugal fan and an air conditioner, which can solve the technical problem of high noise of the centrifugal fan in the prior art. For reference Figures 1-9As shown, the present application provides a kind of blade assembly, the blade assembly is applied to centrifugal fan, the blade assembly includes hub 1 and the fan blade 2 of the outer edge of the hub 1 is fixed, the hub 1 is provided with the windward side of the fan blade 2, the windward side is provided with spoiler 3, the spoiler 3 can be rotatably arranged on the windward side, the airflow entering the centrifugal fan can swing the spoiler 3.

[0036] The present application is provided with spoiler 3 on the windward side, when centrifugal fan works, airflow enters centrifugal fan and impacts the windward side, by setting spoiler 3 on the windward side, airflow will impact spoiler 3 swing, spoiler 3 swing produces disturbance to airflow, so that airflow can be more evenly flow in centrifugal fan to all directions, thereby avoiding vibration generated when airflow flows in centrifugal fan unbalancedly, and the noise generated by the vibration is avoided accordingly.

[0037] Preferably, as shown in Figure 6 And Figure 7 The rotation center of the hub 1 is provided with rotary damper 4, and the spoiler 3 is connected to the hub 1 through the rotary damper 4.

[0038] By setting rotary damper 4, spoiler 3 swings within a certain angle range relative to hub 1, further improves the disturbance of spoiler 3 to air, avoids that spoiler 3 swings with too large frequency and amplitude to generate relatively large speed difference with airflow, and further causes friction noise. In this way, the noise generated when fan blade 2 assembly works is further reduced.

[0039] The "rotary damper 4" of the present application refers to a device that provides resistance to consume kinetic energy, which can make the product obtain gentle mechanical movement and improve the quality and life of the product; "rotary damper 4" can also make the rotation of spoiler 3 relatively slow compared to the rotation of hub 1.

[0040] Preferably, the rotary damper 4 is a "spring-friction combination" damper.

[0041] By setting "rotary damper 4" as "spring-friction combination" damper, the damper is composed of helical spring and friction plate, and the friction pressure can be fine-tuned by adjusting bolt.

[0042] When the hub 1 stops rotating or the spoiler 3 is absolutely balanced by external force, the spoiler 3 can keep the relative position unchanged with the hub 1 under the action of the "spring-friction combination" damper. For example, when the hub 1 is static, the spoiler 3 is in the preset position relative to the hub 1, the hub 1 rotates, the airflow blows the spoiler 3, the spoiler 3 swings relative to the hub 1, and under the action of the "spring-friction combination" damper, the spoiler 3 rotates relative to the hub 1 by a certain angle, and since the airflow cannot be absolutely stable, the angle is in change; when the hub 1 stops rotating, the spoiler 3 stops again in the preset position relative to the hub 1 under the action of the "spring-friction combination" damper. That is, taking the preset position as the starting point, when the spoiler 3 rotates forward relative to the hub 1, the "spring-friction combination" damper can give the spoiler 3 a reverse force, and when the spoiler 3 rotates reversely relative to the hub 1, the "spring-friction combination" damper can give the spoiler 3 a force towards forward rotation; as long as the spoiler 3 is not in the preset position, the "spring-friction combination" damper gives the spoiler 3 a force to return to the preset position.

[0043] The "spring-friction combination" damper has the characteristics that the friction force is linearly related to the "relative rotation speed" (the rotation speed of the spoiler 3 relative to the hub 1), and the spring force is quadratically related to the displacement. This nonlinear damping characteristic makes the wind blade 2 assembly produce a misaligned rotation in the rotating process, the swing frequency forms a phase difference with the impeller rotation frequency, and then effectively weakens the noise. The problem of large noise of the centrifugal fan in high-speed operation is effectively solved, and the running quietness of the air conditioner is significantly improved.

[0044] This relative motion makes the airflow form a more uniform flow state at the hub 1, effectively suppressing vortex noise.

[0045] Through manual measurement, the centrifugal fan with the wind blade 2 assembly of the application has almost no attenuation in air volume at the highest speed (2300 rpm), the total noise value is reduced by 2.3 dB(A), and the rotating noise is reduced by an average of 1.2 dB(A) in the low frequency range, verifying good effect.

[0046] Specifically, the action of the "spring-friction combination" damper on the wind blade 2 and the spoiler 3 basically accords with the formula: wherein R REV is the rotation speed of the spoiler 3, Y REV is the rotation speed of the wind blade 2, and Para1-Para3 are related to the performance coefficient of the damper and are design parameters thereof.

[0047] Preferably, as shown in Figures 2-4 , the spoiler 3 is disc-shaped, the spoiler 3 is arranged concentrically with the hub 1, and the spoiler 3 is provided with a through hole 301.

[0048] The stability of the turbulence disc 3 following the rotation of the hub 1 is improved by making the turbulence disc 3 disc-shaped and arranged concentrically with the hub 1. When the airflow enters the centrifugal fan, the airflow impacting the turbulence disc 3 will form a vortex. The through holes 301 provided on the turbulence disc 3 can eliminate part of the vortex and reduce the noise generated by the vortex. The noise generated by the airflow will collide with the hub 1 through the through holes 301, and the noise reflected in the through holes 301 can be weakened to some extent, achieving the effect of noise reduction. The airflow acts on the inner wall of the through holes 301, which can more conveniently push the turbulence disc 3 to swing (rotate). Even a small airflow can make the turbulence disc 3 rotate relative to the hub 1, so that the relative rotation between the turbulence disc and the hub 1 occurs. The rotation frequency of the hub 1 and the rotation frequency of the turbulence disc 3 form a phase difference. This relative movement makes the airflow at the hub 1 form a more uniform flow state, effectively suppressing vortex noise. The structure of the through holes 301 physically blocks the rotation noise, reduces noise propagation through sound wave interference and energy dissipation.

[0049] The setting of the turbulence disc 3 has a blocking effect on the propagation of noise. Further, an acoustic cavity is formed between the turbulence disc 3 and the hub 1. The acoustic cavity not only further blocks the propagation of noise, but also reduces the friction when the turbulence disc 3 rotates relative to the hub 1.

[0050] Preferably, as shown in Figure 3 In the axial direction projection, the through hole 301 is a regular hexagonal hole.

[0051] The through hole 301 can be a circular hole or a polygonal hole, preferably a regular hexagonal hole. All through holes 301 can form a honeycomb shape, which is conducive to increasing the number of through holes 301 on the turbulence disc 3, thereby reducing the impact and reflection of the airflow on the turbulence disc 3 and reducing airflow noise.

[0052] Further, in the axial direction projection, the hole diameter (when it is a regular hexagonal hole, the hole diameter is the diameter of the circumscribed circle of the regular hexagonal hole) is 2% to 5% of the diameter of the fan blade 2. The number of through holes 301 increases in equal difference along the diameter direction of the turbulence disc 3 from inside to outside. For example, the innermost circle is the first circle, the number of through holes 301 in the first circle is 10, the number of through holes 301 in the second circle is 15, and the number of through holes in the third circle is 20.

[0053] Preferably, as shown in Figure 2 and Figure 3 The turbulence disc 3 is provided with a clearance slot 302, and the fan blade 2 passes through the clearance slot 302. When the hub 1 remains stationary, the turbulence disc 3 forms a gap between the fan blade 2 and the clearance slot 302 under the action of the rotation damper 4.

[0054] When the hub 1 is kept stationary, the spoiler 3 is under the action of the rotary damper 4 to form a gap between the fan blade 2 and the accommodation slot 302, which makes the fan blade 2 have a limiting effect on the rotation of the spoiler 3. When the spoiler 3 rotates to make the fan blade 2 contact the side of the accommodation slot 302, the spoiler 3 no longer rotates. In this way, on the one hand, the rotation angle of the spoiler 3 is within a certain range, and the swing amplitude of the spoiler 3 in a direction is not too large. When the spoiler 3 contacts the fan blade 2, the spoiler 3 will have a rebound action, so that the swing frequency of the spoiler 3 and the rotation frequency of the hub 1 form a preset phase difference, thereby improving the spoiler effect of the spoiler 3 on the airflow, improving the uniformity of the airflow, and effectively suppressing the flow noise of the gas, especially the vortex noise. On the other hand, the swing amplitude of the spoiler 3 is not too large, which can also avoid damage caused by the "spring-friction combination" damper rotating too large an angle.

[0055] Preferably, the edge of the hub 1 is provided with a ring groove around the hub 1, and the edge of the spoiler 3 is provided with a ring plate protruding towards the hub 1, which is clamped into the ring groove and can rotate around the center of the hub 1 in the ring groove.

[0056] The edge of the hub 1 is provided with a ring groove, and the spoiler 3 is provided with a ring plate which can be clamped into the ring groove. The cooperation of the ring groove and the ring plate enables the spoiler 3 to stably swing (rotate) around the circumferential direction of the hub 1, avoiding the fluctuation of the spoiler 3 in the axial direction to cause the airflow velocity to drop.

[0057] Preferably, as shown in Figure 3 In the projection of the axial direction of the hub 1, the shape of the accommodation slot 302 is the same as that of the fan blade 2.

[0058] By making the shape of the accommodation slot 302 the same as that of the fan blade 2, when the spoiler 3 swings and contacts the fan blade 2, the contact area between the spoiler 3 and the fan blade 2 is larger, and the contact surface is part of the profile of the fan blade 2. In this way, the interference caused by the spoiler 3 swinging and hitting the fan blade 2 is reduced.

[0059] The accommodation slot 302 is provided: because the flow channels of the airflow are formed on the suction surface and the pressure surface of the fan blade 2, in the projection of the axial direction, the projection area of the accommodation slot 302 is 1.1-1.3 times the projection area of the fan blade 2.

[0060] Preferably, as shown in Figure 5 and Figure 6 The middle part of the spoiler 3 is protruded to form a protruding part 303 away from the hub 1.

[0061] By making the middle part of the spoiler disc 3 protrude away from the hub 1, on the one hand, the other side of the spoiler disc 3 is concave, i.e. a space for accommodating the rotating damper 4 is formed between the spoiler disc 3 and the hub 1, on the other hand, the middle part of the spoiler disc 3 guides the air flow entering the volute 6 to flow faster to the periphery, which is conducive to improving the air outlet speed of the centrifugal fan.

[0062] The middle part of the spoiler disc 3 protrudes to form a convex shape (the other side is concave), and the outer edge of the hub 1 is provided with a water beating edge provided with the above-mentioned ring groove.

[0063] Specifically, the protruding part of the middle part of the spoiler disc 3 is designed with a three-order Bezier curve, and on the meridian plane of the spoiler disc 3 (the meridian plane is any plane passing through the rotation axis of the spoiler disc 3), the rotation center is the starting point and the radius is the end point, and the design parameters are as follows:

[0064] R_T=P1*T3+P2*T2+P3*T+P4

[0065] H_T=P5*T3+P6*T2+P7*T+P8

[0066] Wherein P1-P8 are design parameters, T is the ratio between the current radius and the radius of the fan blade 2, R_T is the cross-sectional horizontal coordinate, and H_T is the cross-sectional vertical coordinate, as shown in Figure 10 The curve is rotated around the center axis to obtain the model of the fan blade 2.

[0067] Preferably, the side of the spoiler disc 3 away from the hub 1 is provided with a flow guide groove extending along the radial direction of the spoiler disc 3, and when the accommodation groove 302 is provided, one end of the flow guide groove close to the outer edge of the spoiler disc 3 is located between the two adjacent accommodation grooves 302.

[0068] By providing the flow guide groove on the spoiler disc 3, the flow guide groove guides the air flow to flow faster, thereby increasing the flow rate of the air flow; one end of the flow guide groove is located between the two adjacent accommodation grooves 302, and the fan blade 2 is arranged in the accommodation groove 302, so that the air flow flows between the two adjacent fan blades 2, which is conducive to reducing the impact of the air flow on the fan blade 2 in the radial direction, thereby reducing the noise generated by the rotation of the blade assembly. Because the flow rate of the air flow along the flow guide groove is faster, the faster flow rate of the air flow can drive the nearby air flow to flow, especially the part of the air flow flowing through the through hole 301, the flow rate of the air flow after flowing through the through hole 301 is slower, and under the driving of the air flow flowing along the flow guide groove, the air flow can flow faster, which is conducive to improving the air outlet volume of the centrifugal fan.

[0069] Further, the flow guide grooves are not communicated with the through holes 301. The flow guide grooves are multiple, and the multiple flow guide grooves extend from the center of the spoiler 3 to the periphery in a diverging manner.

[0070] The present application also provides a centrifugal fan, which comprises the volute 6 and the blade assembly.

[0071] The centrifugal fan further comprises an air inlet cavity connected to the air inlet of the volute 6, and a frame structure 501 is arranged in the air inlet cavity, which divides the air inlet cavity into a front cavity and a rear cavity. The frame structure 501 contains a filter screen structure 502 in the middle, and the filter screen is generally made of non-woven fabric, which can ensure air filtration efficiency and reduce airflow resistance. The rear cavity comprises a circular hole with a diameter generally less than 300 mm, which is used as a flow guide (flow collector) for the inlet of the volute 6 as a core mechanism of a fresh air component. The circular hole is rounded, and the rounding treatment of the circular hole can eliminate airflow separation. The front cavity of the air inlet cavity is connected to the outdoor through a pipeline. The volute 6 is connected to the cavity surrounded by the flow collector. The horizontal cross section perpendicular to the axis of the volute 6 is generally a spiral line or a simplified spiral line. The volute 6 has an outlet, which can be connected to the main air duct of a household air conditioner indoor unit or a separate air duct for conveying airflow. The volute 6 has a bottom for fixing or connecting a fan blade 2 driving motor. The fan blade 2 and the hub 1 form a squirrel cage type blade assembly, and the hub 1 has a flange structure in the center, which can be adapted to the driving motor.

[0072] The volute 6 is made of metal or engineering plastic injection molding.

[0073] The present application also provides an air conditioner comprising the centrifugal fan.

[0074] The air conditioner is a fresh air conditioner, and the centrifugal fan is a fresh air fan, which is used to send outdoor air into the indoor. When the air conditioner sends fresh air, it has small vibration, small noise and large air volume.

[0075] It is easy for those skilled in the art to understand that the advantageous technical features of the above-mentioned modes can be freely combined and superimposed without conflict.

[0076] The above description is only the preferred embodiment of the present application, and should not be used to limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application should be included in the protection scope of the present application. The above description is only the preferred embodiment of the present application, and should not be used to limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A blade assembly applied to a centrifugal fan, the blade assembly comprising a hub (1) and blades (2) fixed to the outer edge of the hub (1), characterized in that, The side of the hub (1) where the fan blade (2) is located is the windward side. A baffle (3) is provided on the windward side. The baffle (3) is rotatably located on the windward side. The airflow entering the centrifugal fan can cause the baffle (3) to swing.

2. The blade assembly according to claim 1, characterized in that, A rotation damper (4) is provided at the rotation center of the hub (1), and the spoiler (3) is connected to the hub (1) via the rotation damper (4).

3. The blade assembly according to claim 2, characterized in that, The rotary damper (4) is a "spring-friction combination" damper.

4. The blade assembly according to claim 2, characterized in that, The spoiler (3) is disc-shaped and is concentrically arranged with the hub (1). The spoiler (3) has a through hole (301).

5. The blade assembly according to claim 4, characterized in that, In the projection along the axial direction, the through hole (301) is a regular hexagonal hole.

6. The blade assembly according to claim 2, characterized in that, The spoiler disk (3) is provided with a clearance groove (302), and the fan blade (2) passes through the clearance groove (302). When the hub (1) remains stationary, the spoiler disk (3) causes the fan blade (2) and the clearance groove (302) to form a gap under the action of the rotation damper (4).

7. The blade assembly according to claim 6, characterized in that, The edge of the hub (1) is provided with an annular groove surrounding the hub (1), and the edge of the spoiler (3) is provided with an annular plate protruding toward the hub (1). The annular plate is inserted into the annular groove and can rotate around the center of the hub (1) within the annular groove.

8. The blade assembly according to claim 6, characterized in that, On the projection of the hub (1) in the axial direction, the shape of the relief groove (302) is the same as the shape of the fan blade (2).

9. The blade assembly according to any one of claims 4-8, characterized in that, The spoiler disc (3) protrudes from the center away from the hub (1) to form a protrusion (303).

10. The blade assembly according to claim 9, characterized in that, The spoiler disc (3) has a guide groove extending in the radial direction along the side facing away from the hub (1). When a clearance groove (302) is provided, one end of the guide groove near the outer edge of the spoiler disc (3) is located between two adjacent clearance grooves (302).

11. A centrifugal fan, characterized in that, Includes the volute (6) and the blade assembly as described in any one of claims 1-10.

12. An air conditioner, characterized in that, Includes the centrifugal fan as described in claim 11.

Images