CN114370427A

CN114370427A - Impeller, centrifugal fan and range hood

Info

Publication number: CN114370427A
Application number: CN202111567416.8A
Authority: CN
Inventors: 姚杨; 南江; 陈鹏; 胡斯特
Original assignee: Midea Group Co Ltd; Guangdong Midea White Goods Technology Innovation Center Co Ltd
Current assignee: Midea Group Co Ltd; Guangdong Midea White Goods Technology Innovation Center Co Ltd
Priority date: 2021-12-17
Filing date: 2021-12-17
Publication date: 2022-04-19
Also published as: WO2023109295A1

Abstract

The application provides an impeller, centrifugal fan and range hood. The impeller is applied to the centrifugal fan and comprises a front disc, a rear disc and a blade group, wherein the rear disc and the front disc are arranged at intervals; the blade group comprises a plurality of blades connected with the front disk and the rear disk, an air outlet gap is formed between every two adjacent blades at intervals, and each blade is provided with a front edge close to the central axis of the impeller and a tail edge far away from the central axis; the front disc is provided with a shielding surface, the shielding surface is positioned on the outer side of the front edge to shield one end, close to the front disc, of the air outlet gap, and the minimum distance between the shielding surface and the rear disc is smaller than the height, protruding relative to the rear disc, of the front edge of the blade. The impeller can restrain backflow vortexes generated at the upper ends of the blades, weakens the impact of airflow on the blades, and further improves the smoothness of airflow flowing and reduces noise.

Description

Impeller, centrifugal fan and range hood

Technical Field

The application relates to the technical field of range hoods, in particular to an impeller, a centrifugal fan and a range hood.

Background

In the related art, the multi-wing centrifugal fan with the forward curved blades has the characteristics of compact structure, high pressure coefficient, low flow coefficient and the like, so that the multi-wing centrifugal fan is widely applied to a range hood. When the centrifugal fan works, the motor drives the impeller to rotate, the airflow enters the impeller along the axial direction of the impeller and passes through the blades of the impeller under the action of centrifugal force, then flows out outwards along the radial direction of the impeller, and in the process, the flowing direction of the airflow is changed, and the airflow can form a turning angle through the blades. The deflection angle of the airflow close to the air inlet end of the impeller is the largest, so that the airflow is easy to cause flow separation at the upper end of the blade, backflow vortex is generated at the upper end of the blade, the backflow vortex can impact the blade, the airflow cannot be smoothly discharged, noise is increased, and the performance of the impeller is affected.

The prior art does not improve the above content, so that the performance of the impeller is poor.

Disclosure of Invention

The main object of this application is to provide an impeller, centrifugal fan and range hood, this impeller can restrain the produced backward flow swirl in the upper end of blade, weakens the impact of air current to the blade, and then improves the smooth and easy nature and the noise reduction that the air current flows.

In order to achieve the above purpose, the present application provides an impeller applied to a centrifugal fan, the impeller includes a front disk, a rear disk and a blade group, the rear disk and the front disk are arranged at an interval; the blade group comprises a plurality of blades connected with the front disk and the rear disk, an air outlet gap is formed between every two adjacent blades at intervals, and each blade is provided with a front edge close to the central axis of the impeller and a tail edge far away from the central axis; the front disc is provided with a shielding surface, the shielding surface is positioned on the outer side of the front edge to shield one end, close to the front disc, of the air outlet gap, and the minimum distance between the shielding surface and the rear disc is smaller than the height, protruding relative to the rear disc, of the front edge of the blade.

In an embodiment, the front disc includes a disc body, the disc body is disposed in an annular shape, a cross section of the disc body is disposed in a linear shape inclined outward in a radial direction of the impeller, and a lower surface of the cross section forms the shielding surface.

In an embodiment, the front disk further comprises a wind blocking ring extending from the inner periphery of the disk body along the central axis in a direction away from the rear disk.

In one embodiment, the blade comprises a first blade part which is correspondingly positioned on the lower side of the shielding surface, one end of the first blade part, which is close to the front disc, is provided with a chamfer angle so as to form a chamfer angle surface, and the chamfer angle surface is connected and matched with the shielding surface.

In an embodiment, a first insertion piece is arranged on the corner cutting surface, a first insertion hole is arranged on the disc body, and the first insertion piece is inserted into the first insertion hole so as to connect the blade with the disc body.

In one embodiment, the vane further comprises a second vane portion connected to a side of the first vane portion adjacent to the central axis, the second vane portion projecting from an inner side of the first vane portion into the passage inside the impeller.

In an embodiment, a ratio of a radial width of the second blade portion along the impeller to a radius of a circle on which trailing edges of the plurality of blades of the blade group are located is not less than 0 and not more than 0.05.

In an embodiment, the blade further includes a folded portion, the blade is disposed in a concave arc shape from the first blade portion to the second blade portion, and the folded portion is disposed in a bent manner from a side of the second blade portion away from the first blade portion toward a back of the concave arc of the second blade portion and extends toward the first blade portion.

In one embodiment, the ratio of the radius of the circle on which the leading edge of the plurality of blades of the blade group is located to the radius of the circle on which the trailing edge of the plurality of blades of the blade group is located is not less than 0.75 and not more than 0.88.

In one embodiment, the radius of the circle on which the trailing edges of the plurality of blades of the blade group are located is not less than 110mm and not more than 145 mm.

In one embodiment, a ratio of a height of the trailing edge in the direction of the central axis to a height of the leading edge in the direction of the central axis is not less than 0.73 and not more than 0.90.

In an embodiment, the height of the leading edge in the direction of the central axis is not less than 70mm, and not more than 100 mm.

In one embodiment, the blade surfaces of a plurality of blades of the blade group are all arranged in an arc-shaped bending manner towards the same circumferential direction, and the tail edges of the plurality of blades are formed on the same circumcircle; an included angle is formed between a first tangent line at the tail edge of any one of the blades and a second tangent line formed by the circumscribed circle at the tail edge of the blade, and the value range of the included angle is [10 degrees, 20 degrees ].

In an embodiment, the front disc includes a disc body and a plurality of filling blocks disposed on a lower surface of the disc body, each filling block is disposed at an end of the air outlet gap close to the front disc, and the shielding surface is formed on a surface of the filling block facing a front edge of the blade.

In one embodiment, the front disc comprises a disc body and an annular retaining ring arranged along the outer periphery of the disc body, the annular retaining ring surrounds the outer periphery of the blade group close to one end of the front disc, and the blocking surface is formed on the inner peripheral surface of the annular retaining ring.

The application still provides a centrifugal fan, centrifugal fan includes spiral case, motor and as above the impeller, the impeller is located in the spiral case, the back dish with the pivot of motor is connected. The impeller comprises a front disc, a rear disc and a blade group, and the rear disc and the front disc are arranged at intervals; the blade group comprises a plurality of blades connected with the front disk and the rear disk, an air outlet gap is formed between every two adjacent blades at intervals, and each blade is provided with a front edge close to the central axis of the impeller and a tail edge far away from the central axis; the front disc is provided with a shielding surface, the shielding surface is positioned on the outer side of the front edge to shield one end, close to the front disc, of the air outlet gap, and the minimum distance between the shielding surface and the rear disc is smaller than the height, protruding relative to the rear disc, of the front edge of the blade.

The application also provides a range hood, the range hood includes as above centrifugal fan.

The impeller comprises a front disc, a rear disc and a blade group, wherein a shielding surface is arranged on the front disc and is positioned on the outer side of a front edge to shield one end, close to the front disc, of an air outlet gap, the minimum distance between the shielding surface and the rear disc is smaller than the height, convexly arranged relative to the rear disc, of the front edge of each blade, the shielding surface is arranged to enable air flow to enter the front disc and penetrate through the blades of the blade group along the axial direction of the impeller and then to flow outwards along the radial direction of the impeller, the shielding surface can shield partial air flow, close to one end of the front disc, of each blade, the shielded air flow is prevented from being separated due to the fact that the folding angle is too large when the shielded air flow passes through the upper ends of the blades, backflow vortex is generated at the upper ends of the blades, the backflow vortex at the upper ends of the blades is restrained by the shielding surface, and the air flow can smoothly flow outwards along the air outlet gap, the condition that the backflow vortex impacts the blades to generate noise is avoided, so that the noise generated by the impeller is reduced; meanwhile, the shielding surface can also play a role in isolating unstable airflow in the volute from flowing back to the air outlet gap, and the smoothness of the airflow flowing through the impeller is further improved. Therefore, the impeller can improve the smoothness of airflow flowing and reduce noise, and the performance of the impeller is improved.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained according to the structures shown in the drawings without creative efforts.

FIG. 1 is a schematic structural view of an embodiment of a centrifugal fan of the present application;

FIG. 2 is a schematic structural view of an embodiment of an impeller of the present application;

FIG. 3 is a schematic diagram of the structure of FIG. 2 from another perspective;

FIG. 4 is a schematic cross-sectional view of the structure of FIG. 3;

FIG. 5 is a partial schematic structural view of the structure of FIG. 4 taken along the central axis of the impeller;

FIG. 6 is a schematic view of the blade assembly of FIG. 2;

FIG. 7 is a schematic structural view of the front plate of FIG. 3;

FIG. 8 is a schematic diagram of the structure of FIG. 7 from another perspective;

FIG. 9 is an enlarged view taken at A in FIG. 8;

FIG. 10 is a schematic view of the blade of FIG. 2;

FIG. 11 is an enlarged view at B of FIG. 10;

FIG. 12 is a schematic diagram of the structure of FIG. 10 from another perspective;

FIG. 13 is a schematic flow diagram of a gas stream through a conventional impeller;

FIG. 14 is a schematic view of the flow of air through the impeller of the present application;

FIG. 15 is a graph of simulation results of airflow past a conventional impeller;

FIG. 16 is a graph of simulation results of airflow through an impeller of the present application;

fig. 17 is a graph comparing noise spectra of the impeller of the present application and a conventional impeller.

The reference numbers illustrate:

the objectives, features, and advantages of the present application will be further described with reference to the accompanying drawings.

Detailed Description

The technical solutions in the embodiments of the present application will be described clearly and completely with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

It should be noted that if directional indications (such as up, down, left, right, front, and back … …) are referred to in the embodiments of the present application, the directional indications are only used to explain the relative positional relationship between the components, the movement situation, and the like in a specific posture (as shown in the drawings), and if the specific posture is changed, the directional indications are changed accordingly.

In addition, if there is a description of "first", "second", etc. in the embodiments of the present application, the description of "first", "second", etc. is for descriptive purposes only and is not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In addition, technical solutions between various embodiments may be combined with each other, but must be realized by a person skilled in the art, and when the technical solutions are contradictory or cannot be realized, such a combination should not be considered to exist, and is not within the protection scope of the present application.

The application provides an impeller, including the centrifugal fan of this impeller to reach range hood including this centrifugal fan.

Referring to fig. 1 to 4, in an embodiment of an impeller 10 of the present application, the impeller 10 is applied to a centrifugal fan 20, the impeller 10 includes a front disk 100, a rear disk 200 and a blade set 300, and the rear disk 200 is spaced from the front disk 100; the blade group 300 comprises a plurality of blades 310 connecting the front disk 100 and the rear disk 200, an air outlet gap 320 is formed between two adjacent blades 310 at intervals, and the blades 310 have a leading edge 311 close to the central axis of the impeller 10 and a trailing edge 312 far from the central axis (as shown in fig. 5, 6 and 10); the front disc 100 is provided with a shielding surface 110 (as shown in fig. 5, 7 and 9), the shielding surface 110 is located outside the front edge 311 to shield one end of the air outlet gap 320 close to the front disc 100, and a minimum distance between the shielding surface 110 and the rear disc 200 is smaller than a height of the front edge 311 of the blade 310 protruding from the rear disc 200.

It can be understood that an air inlet is formed in the front disc 100, the rear disc 200 and the front disc 100 are arranged at an interval, an air outlet is formed between the outer periphery of the front disc 100 and the outer periphery of the rear disc 200, a channel communicated with the air inlet and the air outlet is formed between the front disc 100 and the rear disc 200, the plurality of blades 310 are arranged in the channel and sequentially arranged at intervals along the circumferential direction of the front disc 100, an air outlet gap 320 is formed between every two adjacent blades 310 at an interval, and air flow is discharged outwards through the plurality of air outlet gaps 320 formed by the plurality of blades 310. The blade surface of a plurality of blades 310 of blade group 300 all is the arc bending setting towards same circumferencial direction, in this application, the crooked direction of blade 310 is the same with the direction of rotation to make the air current can superpose impeller 10's slew velocity when flowing along air-out clearance 320, make the air current can accelerate and obtain higher energy, so set up, under the condition of the same air output, the external diameter of impeller 10 of this application is littleer, can reduce the external diameter of this application impeller 10 promptly.

When the impeller 10 rotates, the airflow enters the channel from the air inlet along the axial direction of the impeller 10, and then the flow direction of the airflow is changed under the action of centrifugal force and the curved shape of the blades, so that the airflow can flow out through the air outlet gap 320 along the radial direction of the impeller 10. In the process, the flow direction of the airflow changes from the axial direction of the impeller 10 to the radial direction to form a turning angle, wherein the turning angle of the airflow passing through the air outlet gap 320 and near one end of the front disk 100 is the largest, and the airflow causes flow separation at the upper ends of the blades 310, so that the airflow generates the backflow vortex 11 at the upper ends of the blades 310.

In order to avoid the above situation, the front disc 100 of the present application is provided with the shielding surface 110, the shielding surface 110 may be located in the air outlet gap 320, or may be located outside the air outlet gap 320, only the shielding surface 110 is located outside the front edge 311, for example, the shielding surface 110 may be formed on the outer surface of the shielding sheet, and the shielding sheet may be located in the air outlet gap 320, or located outside the air outlet gap 320, and only needs to be located at one end of the air outlet gap 320 close to the front disc 100; alternatively, the shielding surface 110 may be formed on the outer surface of a filler block, and the filler block is filled at one end of the air outlet gap 320 close to the front panel 100. It is understood that the shielding surface 110 may be a plane, an arc surface, or an irregular surface, which is not limited herein. The shielding surface 110 can shield one end of the air outlet gap 320 close to the front disk 100, that is, the shielding surface 110 can shield a region where the backflow vortex 11 is easily generated at the upper end of the blade 310, so as to prevent the backflow vortex 11 from being formed in the region.

Further, the minimum distance between the shielding surface 110 and the rear disk 200 is smaller than the height of the front edge 311 of the blade 310 projected with respect to the rear disk 200, as shown in fig. 5, the minimum distance between the shielding surface 110 and the rear disk 200 is H2, the height of the front edge 311 of the blade 310 protruding from the rear disk 200 is H1, H2 < H1, the arrangement is such that the shielding surface 110 is located below the plane of the top end of the front edge 311 of the blade 310 in the radial direction of the impeller 10, which corresponds to the height of the air outlet gap 320 formed by the tail edges 312 of two adjacent blades 310 provided with the shielding surface 110, compared with the height of the air outlet gap 320 formed by the leading edges 311 of the same two blades 310, the former height is smaller than the latter height, that is, the height of the outlet air gap 320 is reduced by providing the shielding surface 110, so that the shielding surface 110 can surely suppress the backflow vortex 11 formed in the area of the outlet air gap 320 near one end of the front disk 100. The present invention suppresses the backflow vortex 11 generated at the upper end of the blade 310 by the shielding surface 110, thereby improving the smoothness of the airflow and reducing the noise caused by the backflow vortex 11.

In addition, when the centrifugal fan 20 works, the impeller 10 rotates fast inside the volute 21 of the centrifugal fan 20, so that an unstable airflow is formed in a gap between the volute 21 and the impeller 10, if the shielding surface 110 is not provided, the unstable airflow flows back to the air outlet gap 320 of the impeller 10 along with the backflow vortex, and the airflow in the impeller 10 cannot be discharged smoothly, therefore, the shielding surface 110 of the present application can also shield the unstable airflow in the volute 21, so that the unstable airflow between the volute 21 and the impeller 10 is prevented from flowing back to the air outlet gap 320 of the impeller 10, and the smoothness of the airflow flowing and the reliability of the centrifugal fan 20 are further improved.

The impeller 10 of the present application includes a front disk 100, a rear disk 200, and a blade group 300, wherein the front disk 100 is provided with a shielding surface 110, the shielding surface 110 is located outside a front edge 311 to shield one end of an air outlet gap 320 close to the front disk 100, a minimum distance between the shielding surface 110 and the rear disk 200 is smaller than a height of the front edge 311 of the blade 310 protruding from the rear disk 200, and the shielding surface 110 is configured to shield a portion of the airflow close to one end of the front disk 100 from the front disk 100 along an axial direction of the impeller 10, and pass through the blade 310 of the blade group 300 under the action of centrifugal force, and then, when the airflow flows outward along a radial direction of the impeller 10, the shielding surface 110 can shield a portion of the airflow close to one end of the front disk 100, so as to avoid a situation that the portion of the shielded airflow generates a backflow vortex 11 at an upper end of the blade 310 due to an excessively large turning angle when the portion of the shielded airflow passes through the blade 310, which causes flow separation of the airflow. The blocking surface 110 not only inhibits the backflow vortex 11 at the upper end of the blade 310, so that the airflow can smoothly flow out along the air outlet gap 320, and the noise generated by the backflow vortex 11 impacting the blade 310 is avoided, thereby reducing the noise generated by the impeller 10; meanwhile, the shielding surface 110 can also play a role in isolating unstable airflow inside the volute casing 21 from flowing back to the air outlet gap 320, so that the smoothness of the airflow flowing through the impeller 10 is further improved. Therefore, the impeller 10 of the present application can improve the smoothness of the airflow and reduce noise, thereby improving the performance of the impeller 10.

Referring to fig. 7 to 9, in an embodiment, the front disc 100 includes a disc body 120, the disc body 120 is disposed in an annular shape, a cross section of the disc body 120 is disposed in a linear shape inclined outward along a radial direction of the impeller 10, and a lower surface of the cross section forms the shielding surface 110. It is understood that the cross section herein is a cross section taken through the central axis of the impeller, the lower surface of the cross section forms the shielding surface 110 such that the distance between the outer peripheral edge of the disk body 120 and the rear disk 200 is smaller than the distance between the inner peripheral edge of the disk body 120 and the rear disk 200, the disk body 120 has an inclined circular ring structure, and the shielding surface 110 is formed on the surface of the disk body 120 on the side facing the rear disk 200, that is, the shielding surface 110 is formed on the lower surface of the disk body 120.

Further, the shielding surface 110 is directly formed on the disc body 120, and other structures are not required to be additionally arranged on the disc body 120 to form the shielding surface 110, so that the disc body 120 is simple in structure, and the reduction of the material cost of the disc body 120 is facilitated; moreover, the shielding surface 110 is arranged in a straight line shape inclined outwards along the radial direction of the impeller 10, and the shielding surface 110 with the straight line-shaped cross section is easy to machine, i.e. the disc body 120 is easy to machine, which is beneficial to reducing the machining difficulty of the disc body 120 and improving the machining efficiency of the disc body 120. Therefore, the disc body 120 of the present application is easy to machine and form, has high machining efficiency and is low in manufacturing cost.

In view of the fact that the air flow is likely to flow along the inner circumferential edge of the disk body 120 to the outside of the disk body 120 when the air flow enters the impeller 10, to avoid this, the front disk 100 further includes a wind blocking ring 130, and the wind blocking ring 130 extends from the inner circumferential edge of the disk body 120 along the central axis in a direction away from the rear disk 200. So set up for the air current of wind inlet department of front bezel 100 can be led and sheltered from to wind-break ring 130, and when the air current that the air inlet that follows front bezel 100 got into was close to the inner wall of wind-break ring 130, wind-break ring 130 can lead the air current, so that the air current is smooth and easy inside the entering impeller 10. Also, the wind blocking ring 130 blocks the flow of air from the inner circumferential edge of the disk body 120 to the outside of the disk body 120 to prevent the loss of air, thereby improving the reliability of the front disk 100. Meanwhile, the wind blocking ring 130 also reinforces the strength of the front disc 100.

Referring to fig. 10 to 12, in an embodiment, the blade 310 includes a first blade portion 313 corresponding to the lower side of the shielding surface 110, one end of the first blade portion 313 close to the front disc 100 is disposed at a chamfer angle to form a chamfer surface 315, and the chamfer surface 315 is connected and matched with the shielding surface 110.

It will be appreciated that the first vane portion 313 may be configured in an arc shape, which is beneficial for guiding the airflow to improve the smoothness of the airflow. The corner cutting surface 315 of the first blade part 313 is arranged in an inclined plane, so that the corner cutting surface 315 is easy to machine and form; moreover, the chamfer surface 315 of the first blade portion 313 is connected and matched with the shielding surface 110 arranged on the disc body 120, the chamfer surface 315 is arranged in an inclined plane, and the matched shielding surface 110 is arranged in a straight line shape which is inclined outwards along the radial direction of the impeller 10, so that the chamfer surface 315 of the blade 310 can be tightly attached to the shielding surface 110 of the disc body 120, and the situation that the blade 310 is not tightly attached to the disc body 120, and a gap exists between the blade 310 and the disc body 120 to influence the flow of air flow and easily generate air flow noise is avoided. It can be seen that the present application improves the smoothness of the airflow flow and thus the performance of the impeller 10 by providing the chamfered surface 315 on the first blade portion 313.

In an embodiment, a first insertion piece 316 is disposed on the corner cutting surface 315, a first insertion hole 121 is disposed on the disk body 120, and the first insertion piece 316 is inserted into the first insertion hole 121 to connect the blade 310 and the disk body 120. It will be appreciated that when the front plate 100 and the blade 310 are assembled, the first insertion piece 316 is inserted into the first insertion hole 121, so that the blade 310 can be precisely positioned and installed.

Further, the first inserting sheet 316 is inserted into the first inserting hole 121 and bent and buckled on the outer surface of the disc body 120, the blade 310 is simply installed by adopting an inserting and buckling mode, and compared with a welding fixing mode in the prior art, the blade 310 and the front disc 100 are simple in assembling process and high in production efficiency.

Further, the blade 310 and the rear disc 200 may also be fixed in an inserting and fastening manner, a second inserting piece 317 is disposed at one end of the blade 310 close to the rear disc 200, a second inserting hole is disposed on the rear disc 200, and the second inserting piece 317 is inserted into the second inserting hole and bent and fastened to the outer surface of the rear disc 200. So set up for blade 310 can accurate location installation, and the fixed mode of blade 310 and back plate 200 is simple, is favorable to improving the packaging efficiency of blade 310 and back plate 200.

Referring to fig. 10 to 12, in an embodiment, in order to improve the smoothness of the airflow, the vane 310 further includes a second vane portion 314 connected to a side of the first vane portion 313 close to the central axis, and the second vane portion 314 extends from an inner side of the first vane portion 313 into the passage inside the impeller 10.

It will be appreciated that the second vane portion 314 may be arcuate to facilitate directing the flow of the air stream, and the first vane portion 313 is integrally formed with the second vane portion 314. The front disc 100 is provided with an air inlet, the front disc 100 is annularly arranged, a channel is formed between the front disc 100 and the rear disc 200, the disc body 120 of the front disc 100 is arranged in an inclined annular shape, the first blade 313 is arranged on the lower side of the disc body 120, the second blade 314 extends out of the channel from the inner side of the first blade 313, and the downward projection of the inner periphery of the front disc 100 falls into the second blade 314, so that the second blade 314 is exposed out of the air inlet. When the air current gets into in the passageway of impeller 10 along the air intake, second blade portion 314 can lead from the air current of air intake inflow to in the air-out clearance 320 that the entering that makes the air current can be quick is formed by second blade portion 314, and then make the air current can be quick outwards flow along air-out clearance 320, thereby improved the smooth and easy nature that the air current flows.

Referring to fig. 5, 6 and 10, in an embodiment, a ratio of a radial width of the second blade portion 314 along the impeller 10 to a radius of a circle on which the trailing edges 312 of the plurality of blades 310 of the blade group 300 are located is not less than 0 and not more than 0.05. It will be appreciated that the trailing edges 312 of the plurality of blades 310 of the blade set 300 lie on a circle having a radius R2, and the second blade portion 314 has a radial width L1 along the impeller 10 of L1/R2 e [0, 0.05 ]. Twice R2 is the diameter of the circle on which the trailing edges 312 of the plurality of blades 310 lie, and is also the diameter of the impeller 10, and the value of the radial width L1 of the second blade portion 314 along the impeller 10 varies with the diameter of the impeller 10.

In order to enable the air flow to smoothly enter the air outlet gap 320 from the air inlet, the radial width of the second blade portion 314 along the impeller 10 is not too long. Considering that the second vane portion 314 is arranged in an arc shape, if the radial width of the second vane portion 314 along the impeller 10 is too long, the curvature of the second vane portion 314 is too large, and the too large curvature of the second vane portion 314 makes the airflow easily break away from the surface of the second vane portion 314 when flowing to the second vane portion 314, so that the airflow flows and separates on the second vane portion 314, and the airflow cannot smoothly flow out along the air outlet gap 320; at this time, noise is also easily generated in the air flow at the second vane portion 314. Meanwhile, when the airflow is attached to and flows along the inner wall surface of the second blade portion 314 to the first blade portion 313 due to the excessively large curvature of the second blade portion 314, the airflow partially flows back toward the second blade portion 314 due to the inertia and the centrifugal force, and the flowing-back airflow generates a vortex between the adjacent blades 310, thereby affecting the smoothness of the airflow. It can be seen that the radial width of the second blade portion 314 along the impeller 10 is not easily too long, which would affect the smoothness of the airflow and generate noise. It is understood that the radial width of the second blade portion 314 along the impeller 10 may be 0, that is, the blade 310 does not have the second blade portion 314, and the ratio of the radial width L1 of the second blade portion 314 along the impeller 10 to the radius R2 of the circle where the trailing edges 312 of the plurality of blades 310 of the blade group 300 are located may be 0, or 0.01, or 0.03, or 0.05, and the like, and is not limited herein.

In order to further improve the smoothness of the airflow, optionally, the blade 310 further includes a folded portion (not shown), the blade 310 is disposed in a concave arc shape from the first blade portion 313 to the second blade portion 314, and the folded portion is bent from a side of the second blade portion 314 away from the first blade portion 313 toward a back surface of the concave arc of the second blade portion 314 and extends toward the first blade portion 313. So set up, make the turn-over portion stretch out to in the inside passageway of impeller 10, the downward projection of turn-over portion falls into the circle that the downward projection of the inner periphery of front bezel 100 formed, the turn-over portion is located the foremost of blade 310, when the air current gets into the passageway from the air intake, the medial surface of blade 310 including the turn-over portion can meet the air current, the turn-over portion can lead the air current promptly, so that most air current can adhere to the flow along the medial surface of blade 310, only the part that only a small part air current lies in the concave arc back of second blade 314 along the turn-over portion adheres to the flow, so make the turn-over portion can restrain the flow separation of the air current of blade 310 foremost, thereby can improve the smooth and easy nature of air current flow and reduce the noise that flow separation produced.

In order to make the vane 310 better cater for the airflow, optionally, the tip of the folded portion is spaced from the outer side surface of the second vane portion 314. Due to the arrangement, the area of the bent part of the folded part is increased, and the tail end of the folded part refers to the tail end of the folded part in extension. When the airflow enters the channel along the air inlet, the airflow firstly flows to the bent part of the folded part, and the area of the folded part is increased, so that most of the airflow is more easily guided to flow along the inner side surfaces of the second blade part 314 and the first blade part 313 by the folded part, and the flow separation of the airflow at the foremost end of the blade 310 is effectively inhibited.

Referring to fig. 5, 6 and 10, in an embodiment, a ratio of a radius of a circle on which a leading edge 311 of the plurality of blades 310 of the blade group 300 is located to a radius of a circle on which a trailing edge 312 of the plurality of blades 310 of the blade group 300 is located is not less than 0.75 and not more than 0.88. It can be understood that the radius of the circle on which the leading edge 311 of the plurality of blades 310 of the blade set 300 is located is R1, the radius of the circle on which the trailing edge 312 of the plurality of blades 310 of the blade set 300 is located is R2, the ratio of R1 to R2 is not less than 0.75 and not more than 0.88, R1/R2 e [0.75, 0.88], the value of R1 varies with the variation of R2, and by defining the ratio of R1 to R2, the size of the blade 310 is correspondingly defined so that the size of the blade 310 can be adapted to the size of the impeller 10.

If the ratio of R1 to R2 is too small, it indicates that the value of R1 is too small, and correspondingly, the size of the vane 310 is too large, and the vane 310 is too large to match the impeller 10, which may easily cause the vane 310 to block the passage, thereby affecting the smoothness of the airflow. If the ratio of R1 to R2 is too large, it indicates that the value of R1 is too large, and correspondingly, the blade 310 is too small, and the air outlet gap 320 formed by the too small blade 310 is smaller, so that the air flow cannot be guided to flow quickly. Thus, preferably, R1/R2 ∈ [0.75, 0.88], e.g. the ratio of R1 to R2 is 0.75, alternatively 0.80, alternatively 0.85, alternatively 0.88.

In one embodiment, the radius of the circle on which the trailing edges 312 of the plurality of blades 310 of the blade set 300 are located is not less than 110mm and not more than 145mm, i.e. the radius of the circle on which the trailing edges 312 of the plurality of blades 310 of the blade set 300 are located is R2, R2 e [110mm, 145mm ]. Twice as much as R2 is the diameter of the circle on which the trailing edges 312 of the plurality of blades 310 of the blade group 300 are located, and is also the diameter of the impeller 10, i.e. the present solution defines the value of R2, which is equivalent to defining the diameter of the impeller 10.

Considering that the impeller 10 is actually applied to the range hood, the size of the range hood can be limited by limiting the diameter of the impeller 10, if the diameter of the impeller 10 is too large, the size of the impeller 10 is large, the impeller 10 occupies a large internal space of the centrifugal fan 20, and thus the size of the range hood is large, and the manufacturing cost of oil smoke absorption is high; if the diameter of the impeller 10 is too small, the exhaust capability of the impeller 10 is poor, and further the exhaust capability of the centrifugal fan 20 is poor, so that the centrifugal fan 20 cannot meet the performance requirement of the range hood. It can be seen that the present application ensures the exhaust amount of the impeller 10 and the applicability of the impeller 10 in the centrifugal fan 20 and the range hood by limiting the value of R2, and preferably, the value of R2 may be 110mm, or 120mm, or 130mm, or 145mm, and the like, and is not limited herein.

Referring to fig. 5, 6 and 10, in an embodiment, a ratio of a height of the trailing edge 312 along the central axis to a height of the leading edge 311 along the central axis is not less than 0.73 and not more than 0.90. It is understood that the height of the leading edge 311 in the direction of the central axis is H1, the height of the trailing edge 312 in the direction of the central axis is H2, H2/H1 ∈ [0.73, 0.90], and the value of H2 varies with the variation of H1. The present application defines the angle of inclination between the cross-section of the shielding face 110 on the front disk 100 and the central axis, i.e. the size of the shielding face 110, by defining the value of H2, which is equivalent to defining the angle of inclination of the chamfer face 315 of the blade 310. By defining the size of the shielding surface 110, the shielding surfaces 110 with different sizes can suppress backflow vortexes 11 with different sizes formed by the upper ends of the blades 310 with different heights, so that the size of the shielding surface 110 can be adapted to the height of the blades 310.

If the ratio of H2 to H1 is too small, that is, the value of H2 is too small, the height of the trailing edge 312 of the blade 310 is too low, which is equivalent to that the inclination angle between the cross section of the shielding surface 110 and the central axis is too small, so that the shielding surface 110 is too large, the height of the air outlet gap 320 is too low, the shielding area of the shielding surface 110 to the air outlet gap 320 is large, the air flow is limited from flowing out of the air outlet gap 320, the air flow is not smooth, and the air exhaust of the impeller 10 is affected. If the ratio of H2 to H1 is too large, that is, the value of H2 is too large, the height of the trailing edge 312 of the blade 310 is too high, which is equivalent to that the inclination angle between the cross section of the shielding surface 110 and the central axis is too large, so that the shielding surface 110 is too small, and the height of the air outlet gap 320 is too high, the shielding area of the shielding surface 110 to the air outlet gap 320 is small, and the shielding surface 110 cannot effectively suppress the backflow vortex 11 generated at the upper end of the blade 310, so that the airflow easily flows back into the air outlet gap 320, which causes noise and affects the smoothness of the airflow flow, and at the same time, the effect of the shielding surface 110 that the unstable airflow inside the volute 21 flows back into the air outlet gap 320 cannot be effectively shielded, so that the shielding effect of the shielding surface 110 is poor. Therefore, the present embodiment ensures that the size of the shielding surface 110 can be adapted to the height of the blade 310 by defining the ratio of H2 to H1, the ratio of H2 to H1 is not less than 0.73 and not more than 0.90, for example, the ratio of H2 to H1 is 0.73, or 0.80, or 0.85, or 0.90, and the like, which is not limited herein.

In one embodiment, the height of the leading edge 311 in the direction of the central axis is not less than 70mm and not more than 100mm, i.e., the height of the leading edge 311 of the blade 310 in the direction of the central axis is H1, H1 e [70mm, 100mm ]. According to the scheme, the size of H1 is limited, namely the height of the impeller 10 is limited, the height of the impeller 10 is not too high or too low easily, if the value of H1 is too small, which is equivalent to the height of the impeller 10 being too low, the exhaust capacity of the impeller 10 is poor, and further the exhaust capacity of the centrifugal fan 20 is poor, so that the centrifugal fan 20 cannot be applied to the range hood; if the value of H1 is too large, which is equivalent to the height of the impeller 10 being too high, the impeller 10 occupies more internal space of the centrifugal fan 20, so that the volume of the centrifugal fan 20 is large, the volume of the range hood is large, the production cost is high, and the centrifugal fan 20 is not suitable for use in the range hood. It can be seen that the present application ensures the exhaust amount of the impeller 10 and the applicability of the impeller 10 in the centrifugal fan 20 and the range hood by limiting the value of H1, and preferably, the value of H1 may be 70mm, 80mm, 90mm, 100mm, etc., and is not limited herein.

Referring to fig. 6, in an embodiment, the blade surfaces of the plurality of blades 310 of the blade group 300 are all curved in an arc shape toward the same circumferential direction, and the trailing edges 312 of the plurality of blades 310 are formed on the same circumcircle; an included angle is formed between a first tangent line at the trailing edge 312 of any one of the blades 310 and a second tangent line formed by the circumscribed circle at the trailing edge 312 of the blade 310, and the value range of the included angle is [10 degrees, 20 degrees ].

Specifically, as can be seen from fig. 6, a first tangent line at the trailing edge 312 of the blade 310 is L2, a second tangent line circumscribing the circle and formed at the trailing edge 312 of the blade 310 is L3, and an included angle α is formed between L2 and L3, the included angle α being defined as [10 ° and 20 ° ], such that the impeller 10 in the present application is a forward centrifugal impeller, and by defining the included angle α, which is equivalent to the size of the included angle formed between the airflow outlet direction and the rotation direction of the impeller 10, and the included angle between the airflow outlet direction and the rotation direction of the impeller 10 being [10 ° and 20 ° ], the airflow can better superpose the speed of the impeller when flowing out along the wind gap 320, so that the airflow can be accelerated to obtain higher kinetic energy, and compared with the impeller 10 with the same air output, the outer diameter of the impeller 10 in the present application is smaller. It can be seen that the outer diameter of the impeller can be reduced by defining the size of the included angle between a first tangent line at the trailing edge 312 of the blade 310 and a second tangent line formed by a circumscribed circle at the trailing edge 312 of the blade 310.

In an embodiment, the front disc 100 includes a disc body 120 and a plurality of filling blocks (not shown) disposed on a lower surface of the disc body 120, each of the filling blocks is disposed at an end of the air outlet gap 320 close to the front disc 100, and the shielding surface 110 is formed on a surface of the filling block facing the front edge 311 of the blade 310. It can be understood that the tray body 120 may be detachably connected to the filling block, and of course, the tray body 120 may also be integrally formed with the filling block, only the filling block is required to be disposed in the air outlet gap 320 formed between the adjacent blades 310 at intervals. The filling block fills and shields one end of the air outlet gap 320 close to the front disc 100, the shape of the air outlet gap 320 is changed by the filling block, so that the filling block can suppress backflow vortex 11 generated at the upper end of the blade 310, the shielding surface 110 is formed on the surface of the filling block facing the front edge 311 of the blade 310, and the beneficial effect of the shielding surface 110 formed on the filling block is the same as that of the shielding surface 110 on the lower surface of the cross section of the disc body 120 in the above scheme, and the description is omitted.

In another embodiment, the front disk 100 includes a disk body 120 and an annular retainer ring (not shown) disposed along an outer periphery of the disk body 120, the annular retainer ring surrounds an outer periphery of the blade assembly 300 near one end of the front disk 100, and the blocking surface 110 is formed on an inner peripheral surface of the annular retainer ring. It can be understood that the annular retainer ring can be detachably connected with the disc body 120, of course, the disc body 120 can also be integrally formed with the annular retainer ring, only the annular retainer ring needs to surround the periphery of the vane assembly 300 close to one end of the front disc 100, the outer surface of the vane assembly 300 can be sleeved with the annular retainer ring, so as to change the shape of the outlet of the air outlet gap 320 formed by the interval arrangement of the adjacent vanes 310, at the moment, the shielding surface 110 is located on the inner peripheral surface of the annular retainer ring, the annular retainer ring can suppress the backflow vortex 11 generated at the upper end of the vanes 310, the beneficial effect of the shielding surface 110 on the annular retainer ring is the same as the beneficial effect of the shielding surface 110 on the annular retainer ring on the lower surface of the cross section of the disc body 120, and the description is omitted here one by one

Referring to fig. 13, fig. 13 is a schematic view illustrating the flow of the air passing through the conventional impeller, and it can be seen from fig. 13 that the air forms a backflow vortex 11 at the upper end of the vane 310.

Referring to fig. 14, fig. 14 is a schematic flow diagram of an air flow passing through the impeller 10 of the present application, and it can be seen from fig. 14 that the shielding surface 110 shields one end of the air outlet gap 320 close to the front disk 100, so as to avoid a situation that the air flow is separated due to an excessively large turning angle when the air flow passes through the upper ends of the blades 310, and the air flow generates a backflow vortex 11 at the upper ends of the blades 310. By arranging the shielding surface 110, the backflow vortex 11 generated at the upper end of the blade 310 can be inhibited, so that the airflow can smoothly flow out along the air outlet gap 320, the condition that the backflow vortex 11 impacts the blade 310 to generate noise is avoided, and the noise generated by the impeller 10 is reduced; meanwhile, the shielding surface 110 can also play a role in isolating unstable airflow inside the volute casing 21 from flowing back to the air outlet gap 320, so that the smoothness of the airflow flowing through the impeller 10 is further improved.

Referring to fig. 15, fig. 15 is a graph of simulation results of airflow passing through a conventional impeller, and it can be seen from fig. 15 that the backflow vortex 11 at the air outlet of the impeller is more and the airflow flow is unstable.

Referring to fig. 16, fig. 16 is a graph of simulation results of airflow passing through the impeller 10 of the present application, and it can be seen from fig. 16 that the backflow vortex 11 at the air outlet of the impeller 10 is significantly reduced, and the airflow flow is more stable, so that the impeller 10 of the present application can suppress the backflow vortex 11 generated at the upper end of the blade 310, reduce the impact of the airflow on the blade 310, and further improve the smoothness of the airflow flow and reduce noise.

In order to verify that the impeller 10 of the present application can achieve the effect of reducing noise, an impeller in the prior art is applied to the range hood C, and the impeller 10 of the present application is applied to the range hood D, wherein the blades 310 in the impeller 10 of the present application include a first blade portion 313 and a second blade portion 314. Table 1 shows the air flowAt 15m³Min to 24m³And testing the noise of the range hood C and the range hood D within a min range, wherein the test data is as follows:

TABLE 1 data of noise test

From the analysis of the above test data, it can be seen that the air volume of the impeller 10 of the present application and the impeller of the prior art is 15m³Min to 24m³In the/min range, the noise generated by the impeller 10 of the present application is reduced by about 1dB over the prior art impellers. It can be seen that the impeller 10 of the present application can achieve a noise reduction effect as compared to the prior art impeller.

Referring to fig. 17, fig. 17 is a comparison graph of noise frequency spectrums of the impeller 10 of the present application and a conventional impeller, wherein the air volume is 18m³Min, the vanes 310 in the impeller 10 include a first vane portion 313 and a second vane portion 314. As can be seen from the data analysis in fig. 17, the impeller 10 of the present application has improved noise generation over the entire broad frequency range relative to the prior art impeller, wherein the noise reduction is mainly from the broad frequency ranges of 250Hz, 800Hz, and 1250 Hz. As can be seen from the above, compared with the impeller in the prior art, the impeller 10 of the present application can improve the unstable flow of the airflow caused by the broadband noise, and has an improvement effect on the main frequency band generating the noise, so that the generation of the noise can be reduced.

Further, in the embodiment of the noise test described above, the vane 310 in the impeller 10 of the present application includes the first vane portion 313 and the second vane portion 314, and the structure of the vane 310 is now adjusted such that the vane 310 includes the first vane portion 313, the second vane portion 314, and the folded portion. The impeller 10 of the present application after adjusting the blades 310 is tested under the same conditions, and the test result shows that the noise generated by the impeller 10 of the present application after adjusting the blades 310 is reduced by about 2dB compared with the noise generated by the impeller of the prior art. It can be seen that the impeller 10 of the present application can achieve a noise reduction effect as compared to the prior art impeller.

The present application further provides a centrifugal fan 20, where the centrifugal fan 20 includes the impeller 10 as described above, and the specific structure of the impeller 10 refers to the above embodiments, and since the centrifugal fan 20 adopts all technical solutions of all the above embodiments, all beneficial effects brought by the technical solutions of the above embodiments are at least achieved, and are not repeated herein.

Optionally, the centrifugal fan 20 further includes a volute 21 and a motor, the impeller 10 is disposed in the volute 21, and a rear disc 200 of the impeller 10 is connected to a rotating shaft of the motor. The impeller 10 provided by the application can improve the smoothness of airflow flow and reduce noise, thereby improving the performance of the centrifugal fan 20.

Centrifugal fan 20 can be applied to more fields, and in another aspect of this application, with this centrifugal fan 20 be applied to kitchen culinary art field, preferably, be applied to in the range hood. The present application also provides a range hood, which includes the centrifugal fan 20 as described above, and the specific structure of the centrifugal fan 20 refers to the above embodiments, and since the range hood adopts all the technical solutions of all the above embodiments, the range hood at least has all the beneficial effects brought by the technical solutions of the above embodiments, and details are not repeated herein. The range hood that this application provided sucks the effect of oil smoke better, and the difficult oil smoke that takes place returns or the phenomenon that the oil smoke can not in time be discharged, has improved range hood's stability greatly.

The above description is only a preferred embodiment of the present application, and not intended to limit the scope of the present application, and all modifications and equivalents of the technical solutions that can be directly or indirectly applied to other related fields without departing from the spirit of the present application are intended to be included in the scope of the present application.

Claims

1. An impeller, is applied to centrifugal fan, its characterized in that includes:

a front plate;

the rear disc and the front disc are arranged at intervals; and

the blade group comprises a plurality of blades connected with the front disk and the rear disk, an air outlet gap is formed between every two adjacent blades at intervals, and each blade is provided with a front edge close to the central axis of the impeller and a tail edge far away from the central axis;

the front disc is provided with a shielding surface, the shielding surface is positioned on the outer side of the front edge to shield one end, close to the front disc, of the air outlet gap, and the minimum distance between the shielding surface and the rear disc is smaller than the height, protruding relative to the rear disc, of the front edge of the blade.

2. The impeller of claim 1, wherein the front disk comprises a disk body, the disk body is annularly arranged, the cross section of the disk body is linearly arranged along the radial direction of the impeller and is inclined outwards, and the lower surface of the cross section forms the shielding surface.

3. The impeller of claim 2, wherein the front disk further comprises a wind-break ring extending from the inner periphery of the disk body along the central axis in a direction away from the rear disk.

4. The impeller as claimed in claim 2, wherein said vanes include a first lobe portion corresponding to the underside of said shroud, said first lobe portion being chamfered adjacent an end of said front disk to form a chamfer, said chamfer engaging said shroud.

5. The impeller as claimed in claim 4, wherein a first insertion piece is provided on the chamfer face, a first insertion hole is provided on the disk body, and the first insertion piece is inserted into the first insertion hole to connect the blade with the disk body.

6. The impeller of claim 4, wherein said vane further comprises a second vane portion connected to a side of said first vane portion adjacent said central axis, said second vane portion projecting from an inner side of said first vane portion into a channel within said impeller.

7. The impeller as claimed in claim 6, wherein the ratio of the radial width of the second vane portion along the impeller to the radius of the circle on which the trailing edges of the plurality of vanes of the vane group lie is not less than 0 and not more than 0.05.

8. The impeller as claimed in claim 6, wherein the blade further comprises a folded portion, the blade is disposed in a concave arc shape from the first blade portion to the second blade portion, and the folded portion is bent from a side of the second blade portion away from the first blade portion toward a back surface of the concave arc of the second blade portion and extends toward the first blade portion.

9. The impeller according to any one of claims 1 to 7, wherein the ratio of the radius of the circle on which the leading edges of the plurality of blades of the blade group lie to the radius of the circle on which the trailing edges of the plurality of blades of the blade group lie is not less than 0.75 and not more than 0.88.

10. The impeller as claimed in claim 9, wherein the trailing edges of the plurality of blades of the blade group lie on a circle having a radius of not less than 110mm and not more than 145 mm.

11. The impeller according to any one of claims 1 to 7, wherein a ratio of a height of the trailing edge in the direction of the central axis to a height of the leading edge in the direction of the central axis is not less than 0.73 and not more than 0.90.

12. The impeller of claim 11, wherein a height of the leading edge in the direction of the central axis is not less than 70mm and not more than 100 mm.

13. The impeller according to claim 1, wherein the blade surfaces of the plurality of blades of the blade group are all curved in an arc shape in the same circumferential direction, and the trailing edges of the plurality of blades are formed on the same circumcircle; an included angle is formed between a first tangent line at the tail edge of any one of the blades and a second tangent line formed by the circumscribed circle at the tail edge of the blade, and the value range of the included angle is [10 degrees, 20 degrees ].

14. The impeller as claimed in claim 1, wherein the front disk includes a disk body and a plurality of filler blocks disposed on a lower surface of the disk body, each of the filler blocks is disposed at an end of the outlet gap adjacent to the front disk, and the shielding surface is formed on a surface of the filler block facing the leading edge of the blade.

15. The impeller according to claim 1, wherein the front disk includes a disk body and an annular retainer ring provided along an outer peripheral edge of the disk body, the annular retainer ring surrounding an outer periphery of the vane group near one end of the front disk, the shielding surface being formed on an inner peripheral surface of the annular retainer ring.

16. A centrifugal fan comprising a volute, a motor and an impeller as claimed in any one of claims 1 to 15, the impeller being disposed within the volute, the back disk being connected to the shaft of the motor.

17. A range hood comprising the centrifugal fan of claim 16.