Axial flow fan, method of manufacturing the same, and range hood including the same

Abstract

The present application relates to the field of axial flow fan, disclose a kind of axial flow fan, its manufacturing method and including its range hood, axial flow fan includes shell, rotating shaft, blade assembly, rear mounting and rear suspension support plate, blade assembly is arranged in the blade flow passage formed between rotating shaft and shell, rotating shaft downstream end is rotatably connected to rear mounting, rear suspension support plate and rear mounting, shell fixed connection, the front part of rear suspension support plate is curved to the leeward side, and the leeward side is protruded, the curved degree gradually increases along the radial direction away from the direction of rotating shaft, so that fluid flows through the rear gradually close to axial, to the residual velocity of the fluid flowing out of blade assembly is recycled, improve the efficiency of axial flow fan.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of axial flow fan, in particular to an axial flow fan with residual speed recovery. BACKGROUND

[0002] In the axial flow fan, the fluid flowing out of the stator blade often has a velocity component perpendicular to the axial direction, and the kinetic energy carried by this part of the velocity component is wasted and cannot be converted into pressure energy, reducing the efficiency of the axial flow fan. SUMMARY

[0003] The technical problem to be solved by the present application is to overcome the low efficiency of the prior art axial flow fan, and to provide an axial flow fan, a manufacturing method thereof, and an extractor hood comprising the same.

[0004] The present application solves the above technical problems by the following technical solutions:

[0005] An axial flow fan comprises:

[0006] a housing;

[0007] a rotating shaft arranged in the housing;

[0008] at least one stage of blade assemblies arranged in a blade flow passage;

[0009] The axial flow fan further comprises a rear suspension plate and a rear mounting member arranged in the housing, the rear mounting member is arranged downstream of the rotating shaft and is rotationally connected with the rotating shaft, and the rear suspension plate is located downstream of the blade assembly and is fixed with the rear mounting member and the housing respectively.

[0010] The rear suspension plate has an outer branch part with a radius greater than or equal to the minimum radius of the downstream end of the blade flow passage, and the rear suspension plate has a front part extending in a first direction along the axial direction towards the outlet of the axial flow fan and forming the leading edge of the rear suspension plate, the windward surface and the leeward surface of the outer branch part in the front part are curved towards the leeward surface side of the rear suspension plate, and the degree of curvature gradually increases in a second direction away from the rotating shaft in the radial direction of the axial flow fan.

[0011] In this scheme, the radius of the outer branch part of the front part of the rear suspension plate is greater than or equal to the minimum radius of the downstream end of the blade flow passage, which has a guiding effect on the fluid flowing out of the blade assembly, and when the flow direction of the fluid flowing out of the blade assembly is negative:

[0012] The front part of the outer supporting part of the rear suspension supporting plate is bent towards the leeward side, so that the profile tangent of the front part of the outer supporting part gradually approaches the axial direction, the flow direction of the fluid passing through this part can be gradually deflected to approach the axial direction, the deflection degree of the fluid relative to the axial direction is reduced, the residual velocity of the fluid is recovered, and the efficiency of the axial flow fan is improved.

[0013] The front part of the outer supporting part is gradually bent in the second direction, so that the bending degree gradually increases from the root to the tip, and the fluid with gradually increasing flow rate flowing through the front part from the root to the tip can have a relatively uniform flow rate.

[0014] Preferably, the radii of the front part at the root and the tip are equal to the minimum radius and the maximum radius of the downstream end of the blade flow passage respectively.

[0015] In this scheme, the fluid in the blade flow passage can be subjected to residual velocity recovery, and the efficiency of the axial flow fan is further improved.

[0016] Preferably, the axial coordinate of the trailing edge of the front part gradually increases in the second direction.

[0017] In this scheme, the axial coordinate of the trailing edge of the front part gradually increases from the root to the tip, which facilitates the gradual increase in the length of the front part in the axial direction from the root to the tip for bending, so that the fluid flows more smoothly.

[0018] Preferably, the rear suspension supporting plate further comprises a rear part, the rear part extends in the first direction and forms a trailing edge of the rear suspension supporting plate, and the thickness of the outer supporting part in the rear part gradually decreases in the first direction.

[0019] Preferably, the profile tangent slope in the equal radius surface of the windward surface and / or the leeward surface of the outer supporting part in the rear part remains unchanged or gradually increases in the first direction.

[0020] In this scheme, the thickness of the outer supporting part in the rear part gradually decreases to form a natural draft angle, which facilitates casting molding.

[0021] Preferably, the front part and the rear part are connected.

[0022] Preferably, the rear suspension supporting plate further comprises an inner supporting part with a radius smaller than the minimum radius of the downstream end of the blade flow passage, and the rear mounting member is mounted on at least the inner supporting part.

[0023] In this scheme, the inner supporting part is provided to mount the rear mounting member, which can reduce the occupation of the axial space of the rotating shaft, facilitate the reduction of the length of the rotating shaft, on the one hand, can reduce the material usage, and reduce the overall weight and cost of the axial flow fan; on the other hand, can make the axial size of the axial flow fan compact.

[0024] Preferably, the thickness of the inner supporting part gradually decreases along the first direction, and the absolute value of the slope of the profile tangent of the windward surface and / or the leeward surface in the equal radius surface remains unchanged or gradually increases along the first direction.

[0025] In this scheme, the thickness of the inner supporting part gradually decreases to form a natural draft angle, which facilitates casting molding.

[0026] Preferably, the outer diameter of the rear mounting part gradually decreases along the first direction, and the maximum radius is equal to the minimum radius of the downstream end of the blade flow passage.

[0027] In this scheme, the surface shape of the rear mounting part is smoothly transitioned, which on the one hand facilitates machining, especially casting molding; on the other hand, the upstream end of the rear mounting part is equal in diameter to the blade flow passage, so that the fluid can flow smoothly from the blade assembly to the rear mounting part and then flow smoothly through the rear mounting part, reducing the dynamic loss of fluid flow.

[0028] Preferably, the radius at the leading edge point of the root of the rear suspension support plate is equal to the minimum radius of the downstream end of the blade flow passage.

[0029] In this scheme, such a setting can improve the convenience of processing the rear suspension support plate, especially when the rear suspension support plate and the rear mounting part are integrally cast, facilitating the axial draft of the outer supporting part of the front part of the rear suspension support plate.

[0030] Preferably, the number of rear suspension support plates is multiple, and they are uniformly arranged around the axial direction, and the average solidity of the rear suspension support plates is greater than or equal to 0.7; preferably, greater than or equal to 1.

[0031] In this scheme, the rear suspension support plates are arranged densely enough to ensure that the residual velocity recovery effect is good enough.

[0032] Preferably, the blade assembly comprises a moving blade mounted on the rotating shaft and a stationary blade mounted on the casing.

[0033] In a single-stage blade assembly, the moving blade is arranged upstream of the stationary blade, the absolute value of the outlet angle of the moving blade is greater than the absolute value of the outlet angle of the stationary blade, and the outlet angle of the stationary blade is between 0° and 40°.

[0034] Preferably, the outlet angle of the stationary blade is preferably between 5° and 20°.

[0035] Preferably, the tangent slope of the profile trailing edge point of the leeward surface of the outer supporting part in the front part in the equal radius surface is positive.

[0036] The manufacturing method of the axial flow fan is used for manufacturing the axial flow fan as any of the above technical solutions, a plurality of the rear suspension support plates are uniformly arranged around the axis and are casted, the leeward surface of one of the two adjacent rear suspension support plates faces the windward surface of the other rear suspension support plate, the connecting line of the tail edge point of the leeward surface of the front part of one of the rear suspension support plates and the front edge point of the front part of the other rear suspension support plate is the parting line in the equal radius surface, and one of the molds is arranged upstream and downstream of the parting line;

[0037] The contour tangent slope of the leeward surface of the outer support part in the front part gradually increases along the first direction, the slope at the tail edge point is negative, and the two molds are pulled out along the axis to obtain at least the outer support part of the rear suspension support plate;

[0038] Or, the contour tangent slope of the leeward surface of the outer support part in the front part gradually increases along the first direction, the slope at the tail edge point is positive, the mold arranged upstream of the parting line is rotated and pulled out along the axis, and the mold arranged downstream of the parting line is pulled out along the axis to obtain at least the outer support part of the rear suspension support plate.

[0039] An oil smoke machine comprises the axial flow fan as any of the above technical solutions, the inlet of the axial flow fan is the inlet of the oil smoke machine or is communicated with the inlet of the oil smoke machine, and the outlet of the axial flow fan is the outlet of the oil smoke machine or is communicated with the outlet of the oil smoke machine.

[0040] The positive progress effect of the present application is that:

[0041] By bending the front part of the outer support part of the rear suspension support plate to the leeward surface side, the contour tangent of the front part of the outer support part gradually approaches the axis, the fluid with negative residual velocity passes through this part, the flow direction can be gradually deflected to approach the axis, the deflection degree of the fluid relative to the axis is reduced, the residual velocity of the fluid is recovered, and the efficiency of the axial flow fan is improved.

[0042] By setting the bending degree of the front part of the outer support part gradually increasing along the second direction, the bending degree gradually increases from the root part to the tip part, so that the fluid with gradually increasing flow rate after flowing through the front part from the root part to the tip part has relatively uniform flow rate. BRIEF DESCRIPTION OF DRAWINGS

[0043] Figure 1 It is a schematic view of the oil smoke machine of embodiment 1;

[0044] Figure 2 It is a schematic view of the outer part of the axial flow fan of embodiment 1;

[0045] Figure 3 It is a schematic view of the inner part of the axial flow fan of embodiment 1;

[0046] Figure 4 Axial fan meridian view for example 1;

[0047] Figure 5 Axial fan isoradius view for example 1;

[0048] Figure 6 Axial fan rear mounting, rear suspension plate view for example 1;

[0049] Figure 7 Axial fan rear suspension plate view for example 1;

[0050] Figure 8 Axial fan rear suspension plate meridian view for example 2;

[0051] Figure 9 Axial fan rear suspension plate outer portion isoradius view for example 2;

[0052] Figure 10 Axial fan front suspension plate isoradius view for example 2;

[0053] Figure 11 Axial fan front suspension plate isoradius view for example 3;

[0054] Figure 12 Axial fan rear suspension plate meridian view for other examples.

[0055] BRIEF DESCRIPTION OF DRAWINGS:

[0056] Axial fan 1000;

[0057] Housing 1, front housing 11, rear housing 12;

[0058] Blade assembly 2;

[0059] Blade 21, first stage blade 211, second stage blade 212, third stage blade 213;

[0060] Vane 22, first stage vane 221, second stage vane 222, third stage vane 223;

[0061] Shaft 3;

[0062] Mounting 4, front mounting 41, rear mounting 42;

[0063] Suspension plate 5;

[0064] Front suspension plate 51;

[0065] Rear suspension plate 52, first portion 521, second portion 522, third portion 523;

[0066] outer support portion 531, inner support portion 532;

[0067] front portion 541, rear portion 542;

[0068] windward face 551, leeward face 552;

[0069] vane flow passage 6;

[0070] hood 2000, outer shell 3000;

[0071] range hood 10000. DETAILED DESCRIPTION

[0072] The present application is further illustrated by the following examples without thereby limiting the present application to the examples.

[0073] Example 1

[0074] The present embodiment provides a range hood, Figures 1-7 The present embodiment provides a range hood,

[0075] As Figure 1 The range hood 10000 includes an axial fan 1000, a hood 2000, and an outer shell 3000. The hood 2000 is fixed to the outer shell 3000, and the axial fan 1000 is installed in the outer shell 3000. The bottom of the hood 2000 is formed with an opening as an inlet of the range hood 10000. The inlet of the axial fan 1000 is communicated with the inlet of the range hood 10000, and the outlet of the axial fan 1000 is formed as an outlet of the range hood 10000.

[0076] In the present embodiment, the length direction, the width direction, and the height direction of the range hood 10000 are respectively the X direction, the Y direction, and the Z direction, which are perpendicular to each other. The Z direction is parallel to the vertical direction. In the drawings of the present application, the Z axis coincides with the axis of the axial fan 1000, and the direction of the Z axis is the direction in which the inlet of the axial fan 1000 faces the outlet, which also corresponds to the direction in which the fluid flows from the upstream to the downstream in the axial fan 1000. For the convenience of the following description, the direction of the Z axis is referred to as the “first direction” hereinafter.

[0077] In other embodiments, the shape and the installation direction of the range hood 10000 can be adjusted according to the use requirements. For example, the inlet of the axial fan 1000 can be set as the inlet of the range hood 10000, such as when the hood 2000 is not provided; or the inlet of the axial fan 1000 can be communicated with the inlet of the range hood 10000. The outlet of the axial fan 1000 can be set as the outlet of the range hood 10000; or the outlet of the axial fan 1000 can be communicated with the outlet of the range hood 10000 through a pipeline.

[0078] As Figures 2-5The axial flow fan 1000 comprises a housing 1, and a rotating shaft 3, a blade assembly 2, two suspension plates 5 including a front suspension plate 51 and a rear suspension plate 52, and two mounting members 4 including a front mounting member 41 and a rear mounting member 42 arranged in the housing 1.

[0079] The blade flow channel 6 is a known concept, and is a flow channel range of the blade assembly 2 in the housing 1 of the axial flow fan 1000 along the Z direction from the leading edge to the trailing edge, Figure 4 The range of the blade flow channel 6 along the Z direction is shown by Z_YPLD. As shown in Figure 4 The blade flow channel 6 is formed between the inner surface of the housing 1 and the surface of other components in the housing 1 except the blade assembly 2, and in the embodiment, the blade flow channel 6 is formed by the inner surface of the housing 1 and the outer surface of the rotating shaft 3; the blade assembly 2 is arranged in the blade flow channel 6. In a preferred embodiment, as shown in Figure 4 The inner diameter of the housing 1 and the outer diameter of the rotating shaft 3 remain constant along the Z direction so that the minimum radius and the maximum radius of the blade flow channel 6 remain constant, thereby forming a stable blade flow channel 6.

[0080] As shown in Figures 3-5 The blade assembly has a stage number K=3, and each single-stage blade assembly 2 comprises two blades including a moving blade 21 and a stationary blade 22, and along the Z direction, a first-stage moving blade 211, a first-stage stationary blade 221, a second-stage moving blade 212, a second-stage stationary blade 222, a third-stage moving blade 213, and a third-stage stationary blade 223 are arranged in sequence and at intervals, the stationary blade 22 is mounted on the housing 1, and the moving blade 21 is mounted on the rotating shaft 3. As shown in Figure 2 The housing 1 of the axial flow fan 1000 comprises a front housing 11 and a rear housing 12, and the flange of the front housing 11 and the flange of the rear housing 12 are fixedly connected.

[0081] As shown in Figure 5 The rotating direction of the rotating shaft 3 is W, and when the fluid flow direction has a component in the same direction as W, the speed is considered to be negative. The component of the fluid not parallel to the Z direction when flowing through the blade assembly is called “pre-whirl”, and when flowing out of the blade assembly, it is called “residual speed”, and when the component is in the same direction as W, it is negative residual speed or negative pre-whirl.

[0082] In a preferred embodiment, as shown in Figure 5 The absolute value of the outlet angle β2 of the moving blade 21 is greater than the absolute value of the outlet angle β4 of the stationary blade 22, and the outlet angle β4 of the stationary blade 22 is ≥0°, so that after the fluid flows through the stationary blade 22, it is deflected relative to the axial direction and then flows to the next-stage moving blade 21, thereby facilitating the generation of negative pre-whirl and improving the pressure rise efficiency of the axial flow fan 1000. The outlet angle is defined in accordance with the American textbook, and is the angle between the tangent direction of the camber line of the blade at the trailing edge and the Z direction. Figure 5 In the embodiment, β4 is positive, and the trailing edge of the stationary blade 22 points in the same direction as the rotating direction of the rotating shaft 3.

[0083] The front suspension support plate 51 is located upstream of the blade assembly 2 and fixed to the housing 1; the front mounting piece 41 is located upstream of the rotating shaft 3 and rotatably connected to the upstream end of the rotating shaft 3, and fixed to the front suspension support plate 51; the rear suspension support plate 52 is located downstream of the blade assembly 2 and fixed to the housing 1; the rear mounting piece 42 is located downstream of the rotating shaft 3 and rotatably connected to the downstream end of the rotating shaft 3, and fixed to the rear suspension support plate 52. The rotatable connection method includes, but is not limited to, connection via bearings. Figure 6 A perspective view of the rear suspension support plate and rear mounting components is shown. The mounting components 4 and suspension support plate 5 are provided to install the rotating shaft 3, avoiding interference with the processing and manufacturing of the blade assembly 2 in the axial flow fan 1000, and improving the ease of manufacturing the axial flow fan 1000.

[0084] In this embodiment, a rear suspension plate 52 is provided to recover the residual velocity of the fluid flowing out of the blade assembly 2, thereby improving the efficiency of the axial flow fan. For the specific principle, please refer to Embodiment 2.

[0085] Example 2

[0086] This embodiment provides an axial flow fan. The main difference between the axial flow fan in this embodiment and that in Embodiment 1 is the shape of the rear suspension plate. The housing, rotating shaft, blade assembly, and rear mounting parts are set up in the same way as in Embodiment 1. For details, please refer to Embodiment 1. Figures 8-10 This is a schematic diagram of this embodiment.

[0087] like Figure 8 , Figure 9 The rear suspension plate 52 has an outer support portion 531 with a radius greater than the minimum radius r1 at the downstream end of the blade flow channel 6, and an inner support portion 532 with a radius less than r1. Figure 8 The dashed line L-R2 in the diagram illustrates the approximate boundary between the outer branch 531 and the inner branch 532. (Example 1) Figure 7 The dashed line L-R1 indicates the approximate boundary between the outer support portion 531 and the inner support portion 532. The rear mounting component 42 is at least fixed to the inner support portion 532. By setting the inner support portion 532 to mount the rear mounting component 42, the axial space occupied by the rear suspension plate 52 on the rotating shaft 3 can be reduced, facilitating a reduction in the length of the rotating shaft 3. This reduces material usage, lowering the overall weight and cost of the axial flow fan 1000; furthermore, it allows for a more compact axial dimension of the axial flow fan 1000. The radius of the outer support portion 531 in the rear suspension plate 52 is greater than or equal to the minimum radius of the downstream end of the blade assembly 2, providing strong guidance for the fluid flowing out from the blade assembly 2. The rear suspension plate 52 can be configured with only the outer support portion 531. For example... Figure 12 In the corresponding embodiment, the rear suspension plate 52 does not have an inner support portion 532.

[0088] like Figure 8The rear suspension support plate 52 has a front part 541 and a rear part 542 connected to each other along the Z direction. The front edge of the rear suspension support plate 52 is formed by the front part 541, and the tail edge of the rear suspension support plate 52 is formed by the rear part 542. The front part 541 is curved, and the thickness T of the rear part 542 gradually decreases along the Z direction. The rear part 542 is arranged to reduce the wake of the fluid flowing through the rear suspension support plate 52, thereby reducing flow loss and noise. Figure 8 The L-Z2 in FIG. 1 is a schematic diagram of the approximate boundary between the front part 541 and the rear part 542. Figure 7 The L-Z1 in FIG. 1 is a schematic diagram of the approximate boundary between the front part 541 and the rear part 542. Figure 8 In Table 1, the various parts of the rear suspension support plate 52 are defined by abbreviations.

[0089] Table 1, rear suspension support plate 52 part division

[0090] Middle portion of rear suspension support plate 52 Abbreviation Front portion 541 in outer support portion 531 First portion 521 Rear portion 542 in outer support portion 531 Second portion 522 Inner support portion 532 Third portion 523

[0091] Figure 9 The rear suspension support plate 52 is arranged in the axial flow fan 1000 Figure 8 The A-A, B-B, and C-C in FIG. 1 are schematic diagrams of the corresponding equal-radius surfaces of the rear suspension support plate 52. The A-A is a part with a radius greater than r1, the B-B is a position with a radius equal to r1, and the C-C is a position with a radius less than r1. The outline of the rear mounting part 42 is shown by the dashed line L2. The equal-radius surface is a virtual cylindrical surface with the axis of the axial flow fan 1000 as the axis. The axial flow fan 1000 has an infinite number of equal-radius surfaces.

[0092] As shown in FIG. 1, Figure 8 , Figure 9 The windward surface 551 and the leeward surface 552 of the first part 521 are both convex and curved toward the leeward surface 552. When the fluid with negative residual velocity flows through the front part 541, the flow direction can gradually deflect to approach the axial direction, reducing the deflection of the fluid relative to the axial direction, recovering the residual velocity of the fluid, and improving the efficiency of the axial flow fan 1000. The direction in which the radius gradually increases in the radial direction of the axial flow fan 1000 is defined as the second direction. The first part 521 is arranged to have a gradually increasing degree of curvature along the second direction, so that the flow rate gradually increases from the root to the tip. After the fluid with gradually increasing flow rate flows through the front part 541, the flow rate is relatively uniform. The side of the rear suspension support plate 52 close to the rear mounting part 42 is the root, and the side close to the housing 1 is the tip. The degree of curvature can be understood as the dimension along the W direction. For example, in different equal-radius surfaces, the greater the total dimension of the first part 521 along the W direction, the greater the degree of curvature, Figure 9The bending degree of the first portion 521 at B-B is less than that at A-A. Further, in order to achieve the same output, the rotational speed of the axial flow fan 1000 can be reduced to improve the efficiency of the axial flow fan 1000, thereby reducing the noise.

[0093] The solidity and average solidity are known concepts. The solidity of a blade can be understood as the chord length of the blade / the distance between two adjacent blades in a single row of blades. The average solidity can be understood as the average of the solidities at different radii. The rear suspension support plate 52 can be regarded as a kind of blade. In a preferred embodiment, there are multiple rear suspension support plates 52, which are uniformly arranged along the axial direction. See Figure 3 ; further, the average solidity of the rear suspension support plate 52 is greater than or equal to 0.7, so that the rear suspension support plate 52 is arranged densely enough to ensure that the residual velocity recovery effect of the rear suspension support plate 52 is good enough. When the average solidity of the rear suspension support plate 52 is greater than or equal to 1, the effect is better.

[0094] In a preferred embodiment, the outlet angle β4 of the stationary blade 22 is between 0° and 40°, so that the fluid generates a large pre-rotation at the outlet of the upper stationary blade 22 and then flows to the lower moving blade 21, thereby improving the efficiency of the axial flow fan 1000 and achieving a good residual velocity recovery effect through the rear suspension support plate 52. Further, when the outlet angle β4 of the stationary blade 22 is between 5° and 20°, the residual velocity recovery effect of the rear suspension support plate 52 is better.

[0095] In a preferred embodiment, as shown in Figure 8 , the radii of the root portion and the tip portion of the front portion 541 are equal to the minimum radius r1 and the maximum radius r2 of the downstream end of the blade passage 6, respectively, so that the rear suspension support plate 52 can recover the residual velocity of the incoming flow in the blade passage 6, thereby further improving the efficiency of the axial flow fan 1000.

[0096] In a preferred embodiment, as shown in Figure 8 , L-Z2 can be regarded as the trailing edge profile of the front portion 541. The axial coordinate of L-Z2 increases with the increase of the radius, i.e., the trailing edge profile point of the front portion 541 is closer to the outlet of the axial flow fan 1000 with the increase of the radius, which is shown as the inclination of L-Z2 to the right in Figure 8 . In this way, the length of the front portion 541 along the axial direction gradually increases with the increase of the radius to facilitate the bending arrangement, so that the fluid flows more smoothly. For example Figure 9 , at A-A and B-B, the front portion 541 at A-A has a larger radius and a larger axial coordinate of L-Z2, so that the front portion 541 is longer and the bending degree is larger and changes more smoothly.

[0097] In a preferred embodiment, as shown in Figure 8, the front edge of the L-Z2 is convexly curved away from the rear suspension support plate 52. In other embodiments, as shown in Figure 7 , the trailing edge profile L-Z1 of the front portion 541 in the rear suspension support plate 52 can be straightly inclined towards the outlet of the axial flow fan 1000.

[0098] In a preferred embodiment, as shown in Figure 8 , Figure 9 , the front portion 541 and the rear portion 542 can be connected to make the axial dimension of the rear suspension support plate 52 compact and facilitate the axial demolding.

[0099] In a preferred embodiment, as shown in Figure 9 , the absolute value of the profile tangent slope of the windward surface 551 of the second portion 522 in the equi-radius surface gradually increases along the first direction, and the same applies to the leeward surface 552; in other embodiments, it can gradually increase or remain unchanged to form a natural demolding angle to facilitate axial demolding. In the present application, in the equi-radius surface, the profile tangent is taken as the two-dimensional coordinate axis in the reverse direction of the Z direction and the W direction; the profile tangent slope is positive, i.e., the angle between the tangent and the Z direction is positive; Figure 9 , the P2 point on the windward surface 551 in the rear portion 542 is shown on the profile tangent L1 of the equi-radius surface, and the slope of L1 is negative.

[0100] In a preferred embodiment, as shown in Figure 8 , the outer diameter of the rear mounting member 42 gradually decreases along the first direction, so that the surface shape of the rear mounting member 42 is smoothly transitioned, which is convenient for processing, especially for casting molding; further, the maximum radius of the rear mounting member 42 is equal to the minimum radius r1 of the downstream end of the blade flow passage 6, which is equal to the diameter of the blade flow passage 6, so that the fluid can flow smoothly from the blade assembly 2 to the rear mounting member 42, and then flow smoothly through the rear mounting member 42, thereby reducing the dynamic loss of fluid flow.

[0101] In a preferred embodiment, as shown in Figure 8 , the radius at the front edge point P1 of the root of the rear suspension support plate 52 is equal to the minimum radius r1 of the downstream end of the blade flow passage 6, which is equal to the maximum radius of the rear mounting member 42, which facilitates the axial demolding of the front portion 541.

[0102] In a preferred embodiment, as shown in Figure 10 , the slope of the tangent L3 of the leeward surface 552 of the first portion 521 at the profile trailing edge point P3 in the equi-radius surface is negative, which facilitates the axial demolding of the first portion 521.

[0103] The plurality of rear suspension support plates 52 provided in the present embodiment can be cast together, as shown in Figure 10The leeward face 552 of the upper rear suspension support plate 52 faces the windward face 551 of the lower rear suspension support plate 52, and the line L-S1 connecting the tail edge point P3 of the leeward face 552 of the first part 521 of the upper rear suspension support plate 52 and the leading edge point P4 of the first part 521 of the lower rear suspension support plate 52 is used as a parting line, and the slope of the line L-S1 at any point on the equal radius surface is positive, for example, the slope of the tangent line L4 at the point P5 is positive; a mold is arranged upstream of the line L-S1, and the mold is pulled in the direction S1, and S1 is opposite to the Z direction; another mold is arranged downstream of the line L-S1, and the mold is pulled in the direction S2, and S2 is the same as the Z direction; thus, the outer support part can be obtained; further, S1 and S2 can be parallel to the axial direction. Further, in the embodiment, the windward face 551 and the leeward face 552 of the inner support part 532, i.e., the third part 523, gradually decrease in thickness along the first direction, and the absolute value of the slope of the profile tangent line of the windward face 551 and the leeward face 552 on the equal radius surface gradually increases along the first direction, and in other embodiments, the absolute value of the slope of the profile tangent line of the windward face 551 and the leeward face 552 on the equal radius surface gradually increases or remains unchanged, so as to form a natural draft angle, and the third part 523 can be cast together with the second part 522 and pulled in the direction S2. Figure 9 , the third part 523, gradually decreases in thickness along the first direction, and the absolute value of the slope of the profile tangent line of the windward face 551 and the leeward face 552 on the equal radius surface gradually increases along the first direction, and in other embodiments, the absolute value of the slope of the profile tangent line of the windward face 551 and the leeward face 552 on the equal radius surface gradually increases or remains unchanged, so as to form a natural draft angle, and the third part 523 can be cast together with the second part 522 and pulled in the direction S2.

[0104] Embodiment 3

[0105] The embodiment provides an axial flow fan, and the axial flow fan in the embodiment is mainly different from the axial flow fans in the embodiments 1 and 2 in the shape of the rear suspension support plate. The settings of the shell, the rotating shaft, the blade assembly and the rear mounting part in the embodiment are the same as those in the embodiments 1 and 2, and details can be referred to the embodiments 1 and 2. Figure 11 FIG. 1 is a schematic diagram of the embodiment.

[0106] As shown in FIG. 1, the axial flow fan comprises a shell 1, a rotating shaft 2, a blade assembly 3 and a rear mounting part 4. Figure 11 The slope of the tangent line L5 of the profile tail edge point P6 of the leeward face 552 of the first part 521 on the equal radius surface is positive, on the one hand, even if the fluid has a lag angle, the fluid flows to the axial direction after passing through the point P6, and the residual speed is recovered to the maximum; on the other hand, the fluid at the tail edge of the preposition part 541 is easy to separate from the surface of the rear suspension support plate 52 due to the change of the surface of the rear suspension support plate 52, and the slope of the tangent line L5 at the point P6 is positive, so as to facilitate the smooth transition of the profile of the preposition part 541 to the postposition part 542 and inhibit the fluid from separating from the surface of the rear suspension support plate 52 after passing through the tail edge of the preposition part 541. Figure 11 The line L-Z3 drawn with a dashed line in FIG. 1 shows the approximate boundary between the preposition part 541 and the postposition part 542.

[0107] The plurality of rear suspension support plates 52 provided in the embodiment can be cast together, and the plurality of rear suspension support plates 52 can be cast together. Figure 11The leeward face 552 of the upper rear suspension support plate 52 faces the windward face 551 of the lower rear suspension support plate 52, and the line L-S2 connecting the tail edge point of the leeward face 552 of the first part 521 of the upper rear suspension support plate 52 and the leading edge point of the first part 521 of the lower rear suspension support plate 52 is used as a parting line, and the slope of the line L-S2 at any point on the equal radius surface is positive; a mold is arranged upstream of the line L-S2, and the mold is pulled out in the reverse direction of the Z direction, and the pulling-out angle of the mold is between the absolute value of the included angle between the line L5 and the axial direction and the absolute value of the included angle between the tangent line at the point with the minimum slope of the tangent line of the line L-S2 and the axial direction, and S3 is a pulling-out direction during the pulling-out process; another mold is arranged downstream of the line L-S2, and the mold is pulled out in the direction S4, and the direction S4 is the same as the Z direction; thus, the outer support part can be obtained. Further, the direction S4 can be parallel to the Z direction.

[0108] Although the specific embodiments of the present application are described above, those skilled in the art should understand that this is only an example, and the protection scope of the present application is defined by the appended claims. Those skilled in the art can make various changes or modifications to the embodiments without departing from the principles and essence of the present application, and these changes and modifications all fall within the protection scope of the present application.

Claims

1. A radial fan, comprising: a housing; a rotating shaft arranged in the housing; and at least one blade assembly arranged in a blade passage; characterized in that the radial fan further comprises a rear suspension plate arranged in the housing and a rear mounting member arranged downstream of the rotating shaft and rotatably connected to the rotating shaft, the rear suspension plate being arranged downstream of the blade assembly and fixed to the rear mounting member and the housing respectively; the rear suspension plate has an outer portion with a radius greater than or equal to a minimum radius of a downstream end of the blade passage, and has a front portion extending in a first direction along an axial direction towards an outlet of the radial fan and forming a leading edge of the rear suspension plate, the windward surface and the leeward surface of the outer portion in the front portion are curved towards the leeward surface side of the rear suspension plate, and the degree of curvature gradually increases in a second direction along a radial direction of the radial fan away from the rotating shaft. The radius of the front portion at a root portion and at a tip portion is equal to the minimum radius and the maximum radius of the downstream end of the blade passage respectively. The axial coordinate of a trailing edge of the front portion gradually increases in the second direction. The rear suspension plate further comprises a rear portion extending in the first direction and forming a trailing edge of the rear suspension plate, and the thickness of the outer portion in the rear portion gradually decreases in the first direction. The absolute value of a profile tangent slope of the windward surface and / or the leeward surface of the outer portion in the rear portion in an equal radius surface remains unchanged or gradually increases in the first direction; and / or, the front portion and the rear portion are connected. The rear suspension plate further comprises an inner portion with a radius less than the minimum radius of the downstream end of the blade passage, and the rear mounting member is arranged on at least the inner portion.

2. The axial fan as set forth in claim 1, wherein The thickness of the inner portion gradually decreases in the first direction, and the absolute value of the profile tangent slope of the windward surface and / or the leeward surface in the equal radius surface remains unchanged or gradually increases in the first direction.

3. The axial fan of claim 1, wherein And / or, the outer diameter of the rear mounting member gradually decreases in the first direction, and the maximum radius is equal to the minimum radius of the downstream end of the blade passage.

4. The axial fan of claim 1 wherein, And / or, the radius of a leading edge point of the root portion of the rear suspension plate is equal to the minimum radius of the downstream end of the blade passage.

5. The axial fan according to claim 4, wherein The number of the rear suspension plates is multiple, and the rear suspension plates are arranged uniformly in the axial direction, and the average solidity of the rear suspension plates is greater than or equal to 0.

7.

6. The axial fan of claim 1 wherein, The average solidity of the rear suspension plates is greater than or equal to 1.

7. The axial fan according to claim 6, wherein The blade assembly comprises a moving blade arranged on the rotating shaft and a stationary blade arranged on the housing. In the single-stage blade assembly, the moving blade is arranged upstream of the stationary blade, the absolute value of an outlet angle of the moving blade is greater than the absolute value of an outlet angle of the stationary blade, and the outlet angle of the stationary blade is between 0° and 40°. The outlet angle of the stationary blade is between 5° and 20°.

8. The axial fan of claim 1 wherein, The tangent slope of the leeward surface of the outer portion in the front portion at a profile trailing edge point in the equal radius surface is positive.

9. The axial fan of claim 8, wherein ​ 10. The axial fan of claim 1 wherein, ​ ​ 11. The axial fan of claim 10, wherein ​ 12. The axial fan of claim 1 wherein, ​ 13. A method of manufacturing an axial flow fan, characterized by, The application relates to a back-hanging plate for a back-hanging type axial flow fan, which is used for manufacturing the axial flow fan as claimed in any one of claims 1-11, a plurality of the back-hanging plates are uniformly arranged along an axial direction and are casted and formed, a leeward surface of one of the back-hanging plates among two adjacent back-hanging plates faces a windward surface of the other back-hanging plate, a connecting line of a tail edge point of the leeward surface of the front part of one back-hanging plate and a front edge point of the front part of the other back-hanging plate is a parting line in an equal radius plane, and one mold is arranged upstream and downstream of the parting line. A contour tangent slope of the leeward surface of the outer part of the front part gradually increases along a first direction in the equal radius plane, the slope at the tail edge point is negative, and the two molds are pulled out along the axial direction to obtain at least the outer part of the back-hanging plate. Or, the contour tangent slope of the leeward surface of the outer part of the front part gradually increases along the first direction in the equal radius plane, the slope at the tail edge point is positive, the mold arranged upstream of the parting line is rotated and pulled out along the axial direction, and the mold arranged downstream of the parting line is pulled out along the axial direction to obtain at least the outer part of the back-hanging plate.

14. A range hood characterized by The application relates to an oil fume exhauster, which comprises the axial flow fan as claimed in any one of claims 1-12, an inlet of the axial flow fan is an inlet of the oil fume exhauster or is communicated with the inlet of the oil fume exhauster, and an outlet of the axial flow fan is an outlet of the oil fume exhauster or is communicated with the outlet of the oil fume exhauster.

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