CN219012939U - Centrifugal fan blade and courtyard machine - Google Patents

Abstract

The application relates to a centrifugal fan blade and a courtyard machine, wherein the centrifugal fan blade comprises a front disc and an air inlet; the chassis is coaxial with the front disc and is arranged at intervals; and the blades are arranged between the front disc and the chassis, are distributed at intervals along the circumferential direction to form an air outlet, are respectively provided with a front edge and a tail edge along the two ends of the length direction of the blades, and are bent towards the direction of the tail edge along the rotating direction of the centrifugal fan blade. Through the leading edge bending towards the direction of trailing edge for the leading edge of blade increases towards air intake department peripheral velocity, and the change of entry air current angle reduces, has reduced the impact of centrifugal fan blade's air intake department air current to the blade, has weakened the energy of vortex, thereby has improved centrifugal fan blade's efficiency, reduces the noise that produces when the air current is impacted, is favorable to the improvement of fan blade performance.

Description

Centrifugal fan blade and courtyard machine

Technical Field

The application relates to the technical field of fans, in particular to a centrifugal fan blade and a courtyard machine.

Background

The fan is used as a general machine and has wide application in various industries; in the household industry, in order to meet the requirements of various cooling and air supply, the use of a fan is also indispensable; the centrifugal fan has the characteristics of high pressure, low flow and capability of changing the direction of air flow, and is most widely applied. The fan blade is a core component of the centrifugal fan, the performance of the fan blade has direct influence on the performance of the whole machine, and the fan blade has quite deep influence on the most visual noise felt by consumers.

Under the current environment, the country is advocating industrial structure upgrading, energy saving and efficiency improvement; with the improvement of living standard, the pursuit of consumers on the quality of life is higher and higher, and the energy efficiency level and the noise level of products are also focused more and more; the centrifugal fan is used as the most extensive machine in the household appliance industry, and is important in improving the performance and reducing the noise; a fan with excellent performance is an urgent need at any time.

Courtyard machine, also known as ceiling machine, ceiling type or embedded type air conditioner. The courtyard machine has the advantages of long air supply distance, attractive appearance and no space occupation, and is favored by more and more consumers. However, the upper blade of the centrifugal fan blade of the raise-boring machine is easy to flow and separate, and the flow passage is blocked, so that noise and power are increased.

Disclosure of Invention

The utility model aims at providing a centrifugal fan blade and courtyard machine reduces the flow separation, and has reduced the impact of air current to the blade when the air inlet, has weakened the energy of vortex, has reduced noise and power, is favorable to the improvement of centrifugal fan blade performance.

According to a first aspect of the present application, the present application provides a centrifugal fan blade, including a front plate having an air inlet; the chassis is coaxial with the front disc and is arranged at intervals; and the blades are arranged between the front disc and the chassis, are distributed at intervals along the circumferential direction to form an air outlet, are respectively provided with a front edge and a tail edge along the two ends of the length direction of the blades, and are bent towards the direction of the tail edge along the rotating direction of the centrifugal fan blade.

In one embodiment of the present application, the blade has an upper edge and a lower edge along its height direction both ends, the upper edge with the front tray is connected, the lower edge with the chassis is connected in the two-dimensional cross section that the lower edge of blade is located, follows the chassis orientation the direction of front tray, the blade reduces along its length direction's size gradually.

In one embodiment of the present application, the leading edge comprises an upper leading edge and a lower leading edge; the upper front edge is connected with the lower front edge and is distributed along the axial direction, the upper front edge is connected with one side of the front disc, which faces the chassis, and the upper front edge is inclined relative to the chassis, and the lower front edge is vertically connected with one side of the chassis, which faces the front disc.

In one embodiment of the present application, the difference between the maximum vertical distance between the lower leading edge and the trailing edge and the minimum vertical distance between the lower leading edge and the trailing edge is L1; the difference between the maximum vertical distance between the upper leading edge and the trailing edge and the minimum vertical distance between the upper leading edge and the trailing edge is L2; wherein, L1 and L2 meet the following conditions: l1 is less than L2 is less than 60mm.

In one embodiment of the present application, the angle between the tangent at the intersection of the upper leading edge and the lower leading edge and the intersection line of the upper leading edge and the lower leading edge is α, and α satisfies the following condition: alpha is less than 90 deg..

In one embodiment of the present application, the offset angle β of the line between the apex of the upper leading edge and the intersection point of the trailing edge and the chassis with respect to the line between the apex of the lower leading edge and the trailing edge and the chassis satisfies the following condition: beta < 40 deg..

In one embodiment of the present application, along any meridian plane of the centrifugal fan blade, the inclination angle θ of the extending direction of the upper front edge with respect to the horizontal direction needs to satisfy the following condition, θ < 90 °.

In one embodiment of the present application, the height dimension of the upper front edge along the axial direction is H2, the height dimension of the upper front edge along the axial direction is H3, and H2 and H3 satisfy the following conditions: e=h2/(h2+h3) < 0.5.

In one embodiment of the present application, the radius of the centrifugal fan blade is R, the minimum inner diameter of the circle formed by the front edges of the plurality of fan blades is R1, the inner diameter of the front disc is R2, b= (R2-R1)/R, a= (R-R1)/R, and a and b satisfy the following conditions: b is less than 0.3, a is less than 0.65.

In an embodiment of the application, the height dimension of the front disc along the axial direction is H1, the height dimension of the centrifugal fan blade along the axial direction is H, and the ratio d of H1 to H satisfies the following conditions: d=h1/H < 0.5.

According to a second aspect of the present application, there is provided a patio machine comprising: the device comprises a shell and an electric appliance component, wherein the electric appliance component is arranged in the shell; and the centrifugal fan blade according to any one of the first aspect, wherein the centrifugal fan blade is arranged in the shell, and the output end of the electrical component is coaxially connected with the centrifugal fan blade.

The application provides a centrifugal fan blade, which comprises a front disc, a rear disc and a fan blade, wherein the front disc is provided with an air inlet; the chassis is coaxial with the front disc and is arranged at intervals; and the blades are arranged between the front disc and the chassis, are distributed at intervals along the circumferential direction to form an air outlet, are respectively provided with a front edge and a tail edge along the two ends of the length direction of the blades, and are bent towards the direction of the tail edge along the rotating direction of the centrifugal fan blade. Through the leading edge bending towards the direction of trailing edge for the peripheral velocity of leading edge towards the import department of blade increases, and the change of entry air current angle reduces, has reduced the impact of air current to the blade in the air intake department of centrifugal fan blade, has weakened the energy of vortex, thereby has improved the efficiency of centrifugal fan blade, reduces the noise that produces when the air current is impacted, is favorable to the improvement of fan blade performance.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, a brief description will be given below of the drawings that are needed in the embodiments or the prior art descriptions, and it is obvious that the drawings in the following description are some embodiments of the present application, and that other drawings can be obtained according to these drawings without inventive effort for a person skilled in the art. In addition, in the drawings, like parts are designated with like reference numerals and the drawings are not drawn to actual scale.

FIG. 1 is a perspective view of a centrifugal fan blade according to the prior art;

FIG. 2 is a cross-sectional view based on any of the meridian planes of FIG. 1;

fig. 3 is a perspective view of a centrifugal fan blade provided in an embodiment of the present application;

FIG. 4 is a top view based on FIG. 3;

FIG. 5 is a top view of the front tray of FIG. 4 with the front tray removed;

FIG. 6 is a cross-sectional view based on any of the meridian planes of FIG. 3;

FIG. 7 is a schematic view of a structure based on the single blade of FIG. 3;

FIG. 8 is a parametric schematic based on the individual blades of FIG. 3;

FIG. 9 is a graph comparing noise values of a centrifugal fan blade and a centrifugal fan blade according to the prior art according to an embodiment of the present application;

fig. 10 is a graph of comparing input power of a motor of a centrifugal fan blade and a centrifugal fan blade according to the prior art according to an embodiment of the present application.

Reference numerals illustrate:

1. a guide ring; 2. centrifugal fan blades; 3. a motor; 4. an electrical box; 5. a housing; 6. an evaporator; 21. a lower end; 22. an upper end; 23. a front plate; 24. a chassis; 25. a pressure surface; 26. a suction surface; 30. a leading edge; 301. an upper leading edge; 302. a lower leading edge; 31. a trailing edge; 32. an upper edge; 33. and a lower edge.

Detailed Description

For the purposes of making the objects, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions of the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is apparent that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, which can be made by one of ordinary skill in the art without undue burden from the present disclosure, are within the scope of the present application based on the embodiments herein.

As shown in fig. 1 and 2, the raise boring machine in the prior art comprises a centrifugal fan blade 2, a motor 3, a shell 5, a guide ring 1, an evaporator 6 and an electric box 4, wherein the centrifugal fan blade 2 is installed on the motor 3, the motor 3 is fixedly installed on a bottom plate of the shell 5, the guide ring 1 is positioned at an inlet of the centrifugal fan blade 2 and installed on the shell 5, and is matched with the centrifugal fan blade 2 coaxially, a part of the guide ring 1 is sunken, and the electric box 4 is installed at a sunken position on the guide ring 1, so that the height of the whole machine can be reduced. The evaporator 6 is annular, surrounds the centrifugal fan blade 2, and is mounted in the housing 5.

However, in the conventional raise boring machine, when the air flow enters the blades from the front disc 23 of the centrifugal fan blade 2, the air flow is changed from axial direction to radial direction, in the direction of the height of the blades, the air flow is unevenly distributed, the air flow speed near the front disc 23 is higher, if the shape of the front edge 30 of the blades is unchanged, the impact loss of the air flow on the air inlets of the blades is larger, the flow loss of the air in the impeller is increased, the efficiency of the impeller is reduced, and the noise is increased.

In view of this, as shown in fig. 3-8, the present application provides a centrifugal fan blade 2, including a front disc 23 having an air inlet; a chassis 24 coaxial with and spaced from the front plate 23; and a plurality of blades disposed between the front plate 23 and the bottom plate 24, and distributed at intervals along a circumferential direction to form an air outlet, wherein two ends of the blades along a length direction thereof are respectively provided with a front edge 30 and a tail edge 31, and the front edge 30 is bent towards the tail edge 31 along a rotation direction of the centrifugal fan blade 2. Through the leading edge 30 bending towards the trailing edge 31, the circumferential speed of the leading edge 30 of the blade towards the inlet is increased, the change of the inlet airflow angle is reduced, the impact of airflow at the air inlet of the centrifugal fan blade 2 on the blade is reduced, and the energy of vortex is weakened, so that the efficiency of the centrifugal fan blade 2 is improved, the noise generated during airflow impact is reduced, and the improvement of the performance of the fan blade is facilitated.

With continued reference to FIG. 3, the blade includes an upper end 22 and a lower end 21, the upper end 22 being inclined relative to the chassis 24, the lower end 21 being perpendicular relative to the chassis 24, the leading edge 30 including an upper leading edge 301 and a lower leading edge 302; the upper front edge 301 is connected to the lower front edge 302 and is distributed in the axial direction, the upper front edge 301 is connected to the side of the front plate 23 facing the chassis 24 and the upper front edge 301 is inclined with respect to the chassis 24, and the lower front edge 302 is connected perpendicularly to the side of the chassis 24 facing the front plate 23.

Specifically, as shown in fig. 7, the blade is formed by an upper front edge 301 and a lower front edge 302 along the axial direction, the lower front edge 302 is the lower end 21 of the front edge 30 of the blade, the lower front edge 302 is vertical to the chassis 24, the upper front edge 301 is the upper end 22 of the front edge 30 of the blade, the upper front edge 301 is inclined relative to the chassis 24, and the front plate 23 and the chassis 24 are respectively disposed at the top and bottom of the blade along the axial direction.

In this embodiment, 7 blades are disposed between the front disk 23 and the chassis 24, and the blades have a pressure surface 25 and a suction surface 26, the pressure surface 25 is used for applying work to the air, the suction surface 26 is oriented toward the center of the centrifugal fan blade 2, the pressure surface 25 is oriented toward the outer periphery of the centrifugal fan blade 2, the interface between the pressure surface 25 and the suction surface 26 toward the outer periphery is a trailing edge 31 of the blade, and the interface between the pressure surface 25 and the suction surface 26 toward the center is a leading edge 30.

With continued reference to fig. 7, the blade has an upper edge 32 and a lower edge 33 at two ends along the height direction thereof, the upper edge 32 is connected with the front plate 23, the lower edge 33 is connected with the chassis 24, and in a two-dimensional section of the lower edge 33 of the blade, the dimension of the blade along the length direction thereof gradually decreases along the direction of the chassis 24 toward the front plate 23.

Specifically, the blade also has an upper edge 32 and a lower edge 33 along the axial direction, the front plate 23 is connected with the upper edge 32 of the blade, the bottom plate 24 is connected with the lower edge 33 of the blade, the blades are uniformly distributed between the front plate 23 and the bottom plate 24 along the circumferential direction, and the front plate 23 and the bottom plate 24 are used for supporting and uniformly distributing the blades. The front end of the centrifugal fan blade 2 is positioned at the air inlet and is called a front edge 30, the tail end of the centrifugal fan blade 2 is positioned at the air outlet and is called a tail edge 31, the front disc 23 of the centrifugal fan blade 2 is used as an upper part, the chassis 24 is used as a lower part, the uppermost end 22 of the centrifugal fan blade is connected with the front disc 23 of the impeller and is called an upper edge 32, and the lowermost end 21 of the centrifugal fan blade is connected with the chassis 24 of the impeller and is called a lower edge 33. The whole blade 34 is divided into an upper half part and a lower half part along the axial direction, wherein the upper half part (namely the upper front edge 301) is offset towards the rotation direction of the centrifugal fan blade 2, and the contact surface of the lower half part (namely the lower front edge 302) and the chassis 24 is vertical to each other and is in a vertical state. The front edge 30 of the blade includes an upper front edge 301 contacting the front disc 23, and a lower front edge 302 contacting the chassis 24, where the upper front edge 301 and the lower front edge 302 are connected to each other, and the boundary is the upper and lower boundaries of the blade. The leading edge 30 of the blade is offset towards the trailing edge 31 of the blade, the lower edge 33 of the blade is offset towards the upper edge 32 from the chassis 24 towards the front disc 23 to a gradually increasing extent, the dimension of the lower edge 33 of the blade in the length direction is L in the two-dimensional blade section where the lower edge 33 is located, the dimension of L at the lower edge 33 is the largest, and L gradually decreases in the process from the lower edge 33 to the upper edge 32. By gradually reducing the L from bottom to top, the flow condition of the upper front edge 301 of the centrifugal fan blade 2 is further improved, the flow separation is reduced, and the performance of the fan blade is improved.

With continued reference to fig. 7 and 8, the difference between the maximum vertical distance between the lower leading edge 302 and the trailing edge 31 and the minimum vertical distance between the lower leading edge 302 and the trailing edge 31 is L1; the difference between the maximum vertical distance between the upper leading edge 301 and the trailing edge 31 and the minimum vertical distance between the upper leading edge 301 and the trailing edge 31 is L2; wherein, L1 and L2 meet the following conditions: l1 is less than L2 is less than 60mm.

Specifically, the upper leading edge 301 and the lower leading edge 302 are each offset to a different extent toward the trailing edge 31. The maximum offset distance of the lower front edge 302 of the blade towards the tail edge 31 is L1, L1 is less than 60mm, preferably l1=15 mm, the maximum offset distance of the upper front edge 301 of the blade towards the tail edge 31 is L2, L2 is less than 60mm, preferably l2=45 mm, and the offset dimension of the upper front edge 301 is larger than the cheap dimension of the lower front edge 302, so that the circumferential speed at the upper front edge 301 of the blade is increased compared with the circumferential speed at the lower front edge 302, the variation of the inlet airflow angle is reduced, the impact of airflow at the air inlet of the centrifugal fan blade 2 on the blade is further reduced, noise generated during airflow impact is reduced, and the improvement of the performance of the fan blade is facilitated.

With continued reference to fig. 7 and 8, the angle between the tangent at the intersection of the upper leading edge 301 and the lower leading edge 302 and the boundary between the upper leading edge 301 and the lower leading edge 302 is α, and α satisfies the following condition: alpha is less than 90 deg.. The upper front edge 301 is projected as a straight line in the direction of illustration, and the angle between the straight line projected by the upper front edge 301 and the plane where the upper front edge 301 and the lower front edge 302 meet is α, α being smaller than 90 °, preferably α=31.5°. That is, the offset angle α of the upper front edge 301 relative to the tail edge 31 is not too large or too small, so that the circumferential speed at the inlet is not too large, and the imbalance between the air inlet and the air outlet caused by too large air inlet volume is prevented, so that the air outlet of the raise-boring machine is not smooth.

With continued reference to fig. 5, the offset angle β of the line between the vertex of the upper leading edge 301 and the intersection point of the trailing edge 31 and the chassis 24 with respect to the line between the vertex of the lower leading edge 302 and the line between the trailing edge 31 and the chassis 24 satisfies the following condition: beta < 40 deg.. As shown in fig. 5, the impeller with the front disc 23 removed is characterized in that the difference beta between the offset angle of the upper front edge 301 and the offset angle of the lower front edge 302 is smaller than 40 degrees, preferably beta=17 degrees, the difference beta between the offset angles is not too large, smooth transition between the upper front edge 301 and the lower front edge 302 is ensured, wind resistance is reduced, air output is improved, and noise is reduced.

With continued reference to fig. 6, along any meridian plane of the centrifugal fan blade 2, the inclination angle θ of the extending direction of the upper front edge 301 with respect to the horizontal direction needs to satisfy the following condition that θ is less than 90 °. On any meridian plane of the centrifugal fan blade 2, the included angle θ between the offset portion of the upper front edge 301 and the horizontal direction is smaller than 90 °, and θ=65° is preferred.

In one embodiment of the present application, the height dimension of the upper front edge 301 along the axial direction is H2, the height dimension of the upper front edge 301 along the axial direction is H3, and the following conditions are satisfied by H2 and H3: e=h2/(h2+h3) < 0.5. The height dimension of the blade of the upper front edge 301 is H2, the height dimension of the lower front edge 302 is H3, e=h2/(h2+h3), which may represent the size of the upper front edge 301 as a whole of the height dimension of the blade, e < 0.5, and preferably e=0.25, such that the offset of the upper front edge 301 of the blade is less than 1/4 of the height of the blade, thereby improving the stability of the blade mounted on the chassis 24.

As shown in fig. 4, the radius of the centrifugal fan blade 2 is R, the smallest inner diameter of the circles formed by the leading edges 30 of the plurality of blades is R1, the inner diameter of the front disc 23 is R2, b= (R2-R1)/R, a= (R-R1)/R, and R, R1 and R2 satisfy the following conditions: b is less than 0.3, a is less than 0.65. The centrifugal fan blade 2 rotates in the anticlockwise direction, the radius of the whole centrifugal impeller is R, the inner diameter of the front disc 23 is R2, the outer diameter of the front disc 23 is the same as the radius of the whole centrifugal impeller, and is R, the minimum inner diameter of a circle formed by the front edges 30 of a plurality of blades is R1, the maximum outer diameter of a circle formed by the tail edges 31 of a plurality of blades is R,220mm < R < 250mm, and preferably, R=230 mm. And, a= (R-R1)/R, a may represent the flow channel size of the entire blade; b= (R2-R1)/R, b may represent the size of the blade axial air intake area; c=a-b, c may represent the radial air outlet area size of the entire blade. The sizes of a, b and c jointly determine the flow path of air, and influence the flow state of the air. Wherein a is less than 0.65, preferably a=0.267, b is less than 0.3, preferably b=0.107, c is less than 0.2, preferably c=0.16, thereby ensuring a better flowing state of air and avoiding excessive noise. xiayu

With continued reference to fig. 6, the axial height dimension of the front disc 23 is H1, the axial height dimension of the centrifugal fan blade 2 is H, and the ratio d of H1 to H satisfies the following condition: d=h1/H < 0.5. The height dimension of the centrifugal fan blade 2 is H,135mm < H < 155mm, preferably h=145 mm, the height of the front disc 23 is H1, d=h1/H, d may represent the axial air inlet area size on any meridian plane of the centrifugal fan blade 2, d < 0.5, preferably d=0.38.

The following test data of tables 1 and 2 are obtained by comparing various data of the centrifugal fan blade 2 of the prior art and the centrifugal fan blade 2 of the present embodiment as follows:

TABLE 1 test data for prior fan blades

Table 2 test data for Fan blade

As shown in fig. 9 and 10, it can be seen from test data that, at the same rotation speed, the air volume of the centrifugal fan blade 2 of the embodiment is increased compared with the air volume of the centrifugal fan blade 2 in the prior art, and the increased amount is 3% of the air volume in the prior art; under the same air quantity, the noise value of the centrifugal fan blade 2 of the embodiment is reduced by 1dBA compared with the noise value of the centrifugal fan blade 2 in the prior art; compared with the centrifugal fan blade 2 in the prior art, the input power of the centrifugal fan blade 2 in the embodiment is reduced by 2W-8W under the condition of the same air quantity. The test data show that the centrifugal fan blade 2 of the embodiment can effectively reduce noise of the raise boring machine, reduce input power, improve working efficiency and effectively solve the problem of high noise of the raise boring machine in the prior art.

Further, the embodiment also provides a raise boring machine, including: a housing 5 and an electrical component, the electrical component being disposed within the housing 5; the centrifugal fan blade 2 according to any one of the first aspect is disposed in the housing 5, and an output end of the electrical component is coaxially connected with the centrifugal fan blade 2.

Here, the "meridian plane" refers to a plane passing through the central axis of the centrifugal fan blade 2.

It should be noted that references in the specification to "one embodiment," "an example embodiment," "some embodiments," etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Furthermore, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to effect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

It should be readily understood that the terms "on … …", "above … …" and "above … …" in this disclosure should be interpreted in the broadest sense such that "on … …" means not only "directly on something", but also includes "on something" with intermediate features or layers therebetween, and "above … …" or "above … …" includes not only the meaning "on something" or "above" but also the meaning "above something" or "above" without intermediate features or layers therebetween (i.e., directly on something).

Further, spatially relative terms, such as "below," "beneath," "above," "over," and the like, may be used herein for ease of description to describe one element or feature's relationship to another element or feature as illustrated. Spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. The device may have other orientations (rotated 90 degrees or at other orientations), and the spatially relative descriptors used herein interpreted accordingly.

It should be noted that in this document, relational terms such as "first" and "second" and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims (11)

1. A centrifugal fan blade, characterized by comprising:

the front plate is provided with an air inlet;

the chassis is coaxial with the front disc and is arranged at intervals; and

the blades are arranged between the front disc and the chassis, are distributed at intervals along the circumferential direction to form an air outlet, are respectively provided with a front edge and a tail edge at two ends along the length direction, and are bent towards the direction of the tail edge along the rotation direction of the centrifugal fan blade.

2. The centrifugal fan blade according to claim 1, wherein the blade has an upper edge and a lower edge at both ends in a height direction thereof, the upper edge being connected to the front plate, the lower edge being connected to the bottom plate, and the blade gradually decreases in size in a length direction thereof in a two-dimensional section where the lower edge of the blade is located in a direction of the bottom plate toward the front plate.

3. A centrifugal fan blade according to claim 1 or 2, wherein the leading edge comprises an upper leading edge and a lower leading edge; the upper front edge is connected with the lower front edge and is distributed along the axial direction, the upper front edge is connected with one side of the front disc, which faces the chassis, and the upper front edge is inclined relative to the chassis, and the lower front edge is vertically connected with one side of the chassis, which faces the front disc.

4. A centrifugal fan blade according to claim 3, wherein the difference between the maximum vertical distance between the lower leading edge and the trailing edge and the minimum vertical distance between the lower leading edge and the trailing edge is L1;

the difference between the maximum vertical distance between the upper leading edge and the trailing edge and the minimum vertical distance between the upper leading edge and the trailing edge is L2;

wherein, L1 and L2 meet the following conditions: l1 is less than L2 is less than 60mm.

5. A centrifugal fan blade according to claim 3, wherein the angle between the tangent at the intersection of the upper and lower leading edges and the boundary line of the upper and lower leading edges is α, and α satisfies the following condition: alpha is less than 90 deg..

6. A centrifugal fan blade according to claim 3, wherein the offset angle β of the line connecting the apex of the upper leading edge and before the intersection of the trailing edge and the chassis with respect to the line connecting the apex of the lower leading edge and between the trailing edge and the chassis satisfies the following condition: beta < 40 deg..

7. A centrifugal fan blade according to claim 3, wherein the angle of inclination θ of the upper leading edge with respect to the horizontal direction along any meridian plane of the centrifugal fan blade is such that θ < 90 °.

8. A centrifugal fan blade according to claim 3, wherein the height dimension of the upper front edge along the axial direction is H2, the height dimension of the upper front edge along the axial direction is H3, and H2, H3 satisfy the following conditions: e=h2/(h2+h3) < 0.5.

9. A centrifugal fan blade according to claim 3, wherein the radius of the centrifugal fan blade is R, the smallest inner diameter of the circle formed by the leading edges of a plurality of the blades is R1, the inner diameter of the front disk is R2, b= (R2-R1)/R, a= (R-R1)/R, and a and b satisfy the following conditions: b is less than 0.3, a is less than 0.65.

10. The centrifugal fan blade according to claim 1, wherein the axial height dimension of the front disc is H1, the axial height dimension of the centrifugal fan blade is H, and the ratio d of H1 to H satisfies the following condition: d=h1/H < 0.5.

11. A raise boring machine, comprising:

the device comprises a shell and an electric appliance component, wherein the electric appliance component is arranged in the shell; and

the centrifugal fan blade according to any one of claims 1-10, wherein the centrifugal fan blade is arranged in the shell, and the output end of the electrical component is coaxially connected with the centrifugal fan blade.

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