Axial flow fan, manufacturing method thereof and range hood comprising axial flow fan

Abstract

The invention relates to the field of axial flow fans, and discloses an axial flow fan, a manufacturing method thereof and a range hood comprising the axial flow fan, the axial flow fan comprises a shell, a rotating shaft, a blade assembly, a rear mounting part and a rear suspension supporting plate, the blade assembly is arranged in a blade flow channel formed between the rotating shaft and the shell, and the downstream end of the rotating shaft is rotationally connected to the rear mounting part; the rear suspension supporting plate is fixedly connected with the rear mounting piece and the shell, the windward side and the leeside in the front part of the rear suspension supporting plate both protrude towards the leeside to be bent, and the bending degree is gradually increased in the direction away from the rotating shaft in the radial direction, so that fluid gradually gets close to the axial direction after flowing through, and the remaining speed of the fluid flowing out of the blade assembly is recovered; and the efficiency of the axial flow fan is improved.

Description

Technical Field

[0001] The invention relates to the field of axial flow fans, and in particular to an axial flow fan with excess speed recovery. Background Art

[0002] In an axial flow fan, the fluid often has a velocity component perpendicular to the axial direction after flowing out from the stator blades. The kinetic energy carried by this velocity component will be dissipated in vain and cannot be converted into pressure energy, thus reducing the efficiency of the axial flow fan. Summary of the invention

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

[0004] The present invention solves the above technical problems through the following technical solutions:

[0005] An axial flow fan, comprising:

[0006] case;

[0007] A rotating shaft is arranged in the housing;

[0008] At least one blade assembly is arranged in the blade flow channel;

[0009] The axial flow fan further comprises a rear suspension support plate and a rear mounting member arranged in the housing, the rear mounting member being arranged downstream of the rotating shaft and rotatably connected to the rotating shaft, the rear suspension support plate being located downstream of the blade assembly and being fixed to the rear mounting member and the housing respectively;

[0010] The rear suspension support plate has an outer branch portion with a radius greater than or equal to the minimum radius of the downstream end of the blade flow channel, and the rear suspension support plate has a front portion, which extends axially in a first direction toward the outlet of the axial flow fan and forms a leading edge of the rear suspension support plate. The windward surface and the leeward surface of the outer branch portion in the front portion are both curved and convex toward the leeward side of the rear suspension support plate, and the degree of curvature gradually increases in a second direction radially away from the rotating shaft of the axial flow fan.

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

[0012] By bending the front part of the outer branch part in the rear suspension support plate toward the leeward side, the contour tangent of the front part of the outer branch part gradually approaches the axial direction. When the fluid passes through this part, the flow direction can be gradually deflected to approach the axial direction, thereby reducing the degree of 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.

[0013] By setting the bending degree of the front part of the outer branch part to gradually increase along the second direction, the bending degree gradually increases from the root to the tip, so that the flow velocity of the fluid with gradually increasing flow velocity from the root to the tip can be relatively uniform after flowing through the front part.

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

[0015] In this solution, such an arrangement can recover the excess velocity of the fluid in the blade flow channel, further improving the efficiency of the axial flow fan.

[0016] Preferably, the axial coordinate of the trailing edge of the leading portion gradually increases along the second direction.

[0017] In this solution, by setting the axial coordinates of the trailing edge of the leading portion to gradually increase from the root to the tip, the axial length of the leading portion gradually increases from the root to the tip for a curved setting, making the fluid flow smoother.

[0018] Preferably, the rear suspension support plate further includes a rear portion, which extends along the first direction and forms a trailing edge of the rear suspension support plate, and a thickness of the outer branch portion in the rear portion gradually decreases along the first direction.

[0019] Preferably, the absolute value of the slope of the contour tangent of the windward surface and / or the leeward surface of the outer branch portion in the rear portion within the surface of equal radius remains unchanged or gradually increases along the first direction.

[0020] In this solution, such an arrangement makes it easier for the thickness of the outer branch part of the rear part to gradually decrease to form a natural draft angle, which is convenient for casting and molding.

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

[0022] Preferably, the rear suspension support plate further includes an inner support portion having a radius smaller than a minimum radius of the downstream end of the blade flow channel, and the rear mounting member is at least mounted on the inner support portion.

[0023] In this solution, by providing an inner support part to install the rear mounting parts, the occupied axial space of the rotating shaft can be reduced, which facilitates reducing the length of the rotating shaft. On the one hand, it can reduce the material usage and reduce the overall weight and cost of the axial flow fan; on the other hand, it can make the axial size of the axial flow fan compact.

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

[0025] In this solution, such an arrangement makes it easier for the thickness of the inner support part to gradually decrease to form a natural draft angle, which is convenient for casting and molding.

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

[0027] In this scheme, the surface shape of the rear mounting part has a smooth transition. On the one hand, it is easy to process, especially easy to cast and mold; on the other hand, the upstream end of the rear mounting part has the same diameter as the blade flow channel, 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, thereby reducing the fluid flow power loss.

[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 channel.

[0029] In this solution, such an arrangement can improve the convenience of processing the rear suspension support plate, especially when the rear suspension support plate and the rear mounting part are cast as one piece, it is convenient to axially demould the outer support part of the front part of the rear suspension support plate.

[0030] Preferably, there are multiple rear suspension support plates, which are evenly spaced around the axial direction, and the average consistency of the rear suspension support plates is greater than or equal to 0.7; preferably, greater than or equal to 1.

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

[0032] Preferably, the blade assembly includes moving blades mounted on the rotating shaft and stationary blades mounted on the housing;

[0033] In the 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 between 5° and 20°.

[0035] Preferably, the slope of the tangent line of the leeward surface of the outer branch portion in the front portion at the trailing edge point of the contour in the equal radius surface is positive.

[0036] A method for manufacturing an axial flow fan, which is used to manufacture an axial flow fan as described in any of the above technical solutions, wherein a plurality of rear suspension support plates are evenly arranged around the axial direction and cast, the leeward side of one of the two adjacent rear suspension support plates faces the windward side of the other rear suspension support plate, and a line connecting the trailing edge point of the leeward side of the front part of one rear suspension support plate and the leading edge point of the front part of the other rear suspension support plate in a surface of equal radius is a parting line, and a mold is provided upstream and downstream of the parting line;

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

[0038] Or, the slope of the contour tangent of the leeward surface of the outer branch part in the front part within the equal radius surface gradually increases along the first direction, and the slope at the trailing edge point is positive, the mold arranged upstream of the parting line is axially rotated and drafted, and the mold arranged downstream of the parting line is axially drafted to obtain at least the outer branch part of the rear suspension support plate.

[0039] A range hood, comprising an axial flow fan as described in any of the above technical solutions, wherein the inlet of the axial flow fan is the inlet of the range hood or is connected to the inlet of the range hood, and the outlet of the axial flow fan is the outlet of the range hood or is connected to the outlet of the range hood.

[0040] The positive and progressive effects of the present invention are:

[0041] The front part of the outer branch part in the rear suspension support plate is bent toward the leeward side, so that the contour tangent of the front part of the outer branch part gradually approaches the axial direction. When the fluid with negative residual velocity passes through this part, the flow direction can be gradually deflected to approach the axial direction, thereby reducing the degree of 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.

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

[0043] Figure 1 is a schematic diagram of a range hood according to Embodiment 1;

[0044] Figure 2 This is an external schematic diagram of the axial flow fan of Example 1;

[0045] Figure 3 This is a schematic diagram of the interior of the axial flow fan of Example 1;

[0046] Figure 4 This is a meridian view of the axial flow fan of Example 1;

[0047] Figure 5 This is a schematic diagram of an equal radius surface of the axial flow fan of Example 1;

[0048] Figure 6 This is a schematic diagram of the rear mounting member and the rear suspension support plate of Example 1;

[0049] Figure 7 This is a schematic diagram of the rear suspension support plate of Example 1;

[0050] Figure 8 This is a meridian view of the rear suspension support plate of the axial flow fan of Example 2;

[0051] Fig. 9 It is a schematic diagram of the outer support portion of the rear suspension support plate of Example 2 on a surface of equal radius;

[0052] Fig.10 Schematic diagram of the drafting of the front suspension support plate on the equal radius surface in Example 2;

[0053] Fig.11 Schematic diagram of the demoulding of the front suspension support plate on the equal radius surface in Example 3;

[0054] Fig.12 This is a meridian view of the rear suspension support plate of the axial flow fan in other embodiments.

[0055] Description of reference numerals:

[0056] Axial fan 1000;

[0057] Shell 1, front shell 11, rear shell 12;

[0058] Blade assembly 2;

[0059] Moving blade 21, first-stage moving blade 211, second-stage moving blade 212, third-stage moving blade 213;

[0060] Stationary blade 22, first-stage stationary blade 221, second-stage stationary blade 222, third-stage stationary blade 223;

[0061] Axis 3;

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

[0063] Suspension support plate 5;

[0064] Front suspension support plate 51;

[0065] The rear suspension support plate 52, the first portion 521, the second portion 522, and the third portion 523;

[0066] An outer branch portion 531 and an inner branch portion 532;

[0067] Pre-part 541, post-part 542;

[0068] Windward side 551, leeward side 552;

[0069] Blade flow channel 6;

[0070] Fume hood 2000, housing 3000;

[0071] Range hood 10000. DETAILED DESCRIPTION

[0072] The present invention is further described below by way of examples, but the present invention is not limited to the scope of the examples.

[0073] Example 1

[0074] This embodiment provides a range hood, Figure 1-Figure 7 It is a structural schematic diagram of this embodiment.

[0075] like Figure 1 The range hood 10000 includes an axial flow fan 1000, a fume hood 2000 and a housing 3000. An opening is formed at the bottom of the fume hood 2000 to serve as an inlet of the range hood 10000. The housing 3000 and the fume hood 2000 are fixed. The axial flow fan 1000 is installed in the housing 3000. The inlet of the axial flow fan 1000 is connected to the inlet of the range hood 10000, and the outlet of the axial flow fan 1000 forms the outlet of the range hood 10000.

[0076] In this embodiment, the length direction, width direction, and 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, and the Z direction is parallel to the vertical direction. In the drawings of the present invention, the Z axis coincides with the axis of the axial flow fan 1000, and the direction of the Z axis is the direction from the inlet to the outlet of the axial flow fan 1000, which also corresponds to the direction of the fluid flowing from the upstream to the downstream in the axial flow fan 1000. For the convenience of the following description, the direction of the Z axis is referred to as the "first direction" below.

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

[0078] like Figure 2-Figure 5The axial flow fan 1000 includes a housing 1, and a rotating shaft 3, a blade assembly 2, two types of suspension support plates 5, namely a front suspension support plate 51 and a rear suspension support plate 52, and two types of mounting parts 4, namely a front mounting part 41 and a rear mounting part 42, which are arranged in the housing 1.

[0079] The blade flow channel 6 is a well-known concept, which is the flow channel range of the blade assembly 2 in the housing 1 of the axial flow fan 1000 from the leading edge to the trailing edge along the Z direction. Figure 4 In FIG. 1 , Z_YPLD is used to indicate the range of the blade flow channel 6 along the Z direction. Figure 4 The inner surface of the housing 1 and the surfaces of other parts of the housing 1 except the blade assembly 2 form a blade channel 6. In this embodiment, the blade channel 6 is formed by the inner surface of the housing 1 and the outer surface of the shaft 3; the blade assembly 2 is arranged in the blade channel 6. In a preferred embodiment, Figure 4 The inner diameter of the housing 1 and the outer diameter of the rotating shaft 3 are kept constant along the Z direction so that the minimum radius and the maximum radius of the blade flow channel 6 are kept constant, forming a stable blade flow channel 6.

[0080] like Figure 3-Figure 5 , the number of stages of the blade assembly K=3, the single-stage blade assembly 2 includes two types of blades, the moving blade 21 and the stationary blade 22, along the Z direction, the first-stage moving blade 211, the first-stage stationary blade 221, the second-stage moving blade 212, the second-stage stationary blade 222, the third-stage moving blade 213, and the third-stage stationary blade 223 are arranged in sequence, the stationary blade 22 is installed on the housing 1, and the moving blade 21 is installed on the rotating shaft 3. Figure 2 The housing 1 of the axial flow fan 1000 includes 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] like Figure 5 , the rotation direction of the rotating shaft 3 is W, and when the fluid flow direction has a velocity component in the same direction as W, the velocity can be considered negative. The component of the fluid that is not parallel to the Z direction can be called "pre-rotation" when it flows to the blade assembly, and can be called "residual velocity" when it flows out of the blade assembly. When this component is in the same direction as W, it is negative residual velocity or negative pre-rotation.

[0082] In a preferred embodiment, if 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 deflects relative to the axial direction before flowing to the next-stage moving blade 21, which is convenient for generating negative pre-swirl and can improve the pressure rise efficiency of the axial flow fan 1000. The definition of the outlet angle is consistent with that in American textbooks, which is the angle between the tangent direction of the arc line in the blade at the trailing edge and the Z direction. Figure 5 When β4 is positive, the trailing edge of the stationary blade 22 points in the same direction as the rotation direction of the shaft 3.

[0083] The front suspension support plate 51 is arranged upstream of the blade assembly 2 and fixed on the housing 1; the front mounting member 41 is arranged upstream of the rotating shaft 3 and is rotatably connected to the upstream end of the rotating shaft 3 and is fixed to the front suspension support plate 51; the rear suspension support plate 52 is arranged downstream of the blade assembly 2 and is fixed to the housing 1; the rear mounting member 42 is arranged downstream of the rotating shaft 3 and is rotatably connected to the downstream end of the rotating shaft 3 and is fixed to the rear suspension support plate 52. The rotation connection method includes but is not limited to connection through a bearing. Figure 6 The mounting member 4 and the suspension support plate 5 are provided to install the rotating shaft 3, so as to avoid affecting the processing and manufacturing of the blade assembly 2 in the axial flow fan 1000 and improve the convenience of manufacturing the axial flow fan 1000.

[0084] In this embodiment, a rear suspension support 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. The specific principle can be referred to in Example 2.

[0085] Example 2

[0086] The present embodiment provides an axial flow fan. The difference between the axial flow fan in the present embodiment and that in Embodiment 1 mainly lies in the different shape of the rear suspension support plate. The configuration of the shell, rotating shaft, blade assembly, and rear mounting parts in the present embodiment are the same as those in Embodiment 1, and specific reference may be made to Embodiment 1. Figure 8-Figure 10 is a schematic diagram of this embodiment.

[0087] like Figure 8 , Fig. 9 The rear suspension support plate 52 has an outer branch portion 531 with a radius greater than the minimum radius r1 of the downstream end of the blade flow channel 6, and an inner branch portion 532 with a radius smaller than r1. Figure 8 The dashed line L-R2 in the figure shows the approximate boundary between the outer branch portion 531 and the inner branch portion 532. Figure 7 L-R1 drawn with a dotted line in the figure illustrates the approximate boundary between the outer branch portion 531 and the inner branch portion 532. The rear mounting member 42 is fixed at least on the inner branch portion 532. By providing the inner branch portion 532 to install the rear mounting member 42, the axial space occupied by the rear suspension support plate 52 for the rotating shaft 3 can be reduced, which facilitates reducing the length of the rotating shaft 3. On the one hand, the amount of material used can be reduced, and the overall weight and cost of the axial flow fan 1000 can be reduced; on the other hand, the axial size of the axial flow fan 1000 can be made compact. The radius of the outer branch portion 531 in the rear suspension support plate 52 is greater than or equal to the minimum radius of the downstream end of the blade assembly 2, and has a strong guiding effect on the fluid flowing out of the blade assembly 2. The rear suspension support plate 52 can be provided with only the outer branch portion 531. For example Fig.12 In the corresponding embodiment, the rear suspension support plate 52 is not provided with the 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 at the front part 541, and the rear edge of the rear suspension support plate 52 is formed at 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 provided to reduce the wake of the fluid after flowing through the rear suspension support plate 52, thereby reducing flow loss and noise. Figure 8 The dashed line L-Z2 in FIG. 5 illustrates the approximate boundary between the front portion 541 and the rear portion 542. Figure 7 The dashed line L-Z1 in FIG. 5 illustrates the approximate boundary between the front portion 541 and the rear portion 542. Figure 8 , Table 1, in the present invention, various parts of the rear suspension support plate 52 are defined by abbreviated names.

[0089] Table 1: Part division of rear suspension support plate 52

[0090] Rear suspension support plate 52 middle part Abbreviation The front part 541 in the outer branch part 531 Part 1521 The rear part 542 of the outer branch part 531 Part II 522 Inner branch 532 Part III 523

[0091] Fig. 9 The rear suspension support plate 52 is Figure 8 Schematic diagram of the equal-radius surfaces corresponding to AA, BB, and CC, AA belongs to the part with a radius greater than r1, BB is the position with a radius equal to r1, CC is the position with a radius less than r1, and the dotted line L2 indicates the outline of the rear mounting part 42; the equal-radius surface is a virtual cylindrical surface with the axis of the axial flow fan 1000 as the axis, and the axial flow fan 1000 has countless equal-radius surfaces.

[0092] like Figure 8 , Fig. 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 be gradually deflected to approach the axial direction, reducing the degree of deflection of the fluid relative to the axial direction, and recovering the residual velocity of the fluid to improve 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 set to gradually increase the degree of curvature along the second direction, so that the degree of curvature gradually increases from the root to the tip, so that the fluid with gradually increasing flow velocity from the root to the tip can have a more uniform flow velocity after passing through the front part 541. The side of the rear suspension support plate 52 that is radially close to the rear mounting part 42 is the root, and the side that is close to the shell 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 larger the total dimension of the first part 521 along the W direction, the greater the degree of curvature, Fig. 9The bending degree of the first portion 521 at BB is smaller than that at AA. Furthermore, due to the improvement of the efficiency of the axial flow fan 1000, in order to achieve the same output, the rotation speed of the axial flow fan 1000 can be reduced, thereby reducing noise.

[0093] Consistency and average consistency are well-known concepts. Blade consistency can be understood as the chord length of the blade / the distance between two adjacent blades in a single row of blades, and average consistency can be understood as the average consistency at different radii. The rear suspension support plate 52 can be regarded as a blade. In a preferred embodiment, there are multiple rear suspension support plates 52, which are evenly spaced around the axial direction. See Figure 3 Furthermore, the average consistency 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 rear suspension support plate 52 has a good enough effect of recovering the residual speed. When the average consistency of the rear suspension support plate 52 is set to be 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-swirl at the outlet of the upper stationary blade 22 and then flows to the lower moving blade 21, so as to improve the efficiency of the axial flow fan 1000, and the effect of recovering the excess velocity through the rear suspension support plate 52 is sufficiently good; further, when the outlet angle β4 of the stationary blade 22 is set between 5° and 20°, the effect of recovering the excess velocity by the rear suspension support plate 52 is better.

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

[0096] In a preferred embodiment, if Figure 8 , L-Z2 can be regarded as the trailing edge contour of the front part 541. The axial coordinate of L-Z2 increases with the increase of the radius, that is, the trailing edge contour point of the front part 541 is closer to the outlet of the axial flow fan 1000 as the radius increases. Figure 8 In the figure, L-Z2 is tilted to the right; such a configuration facilitates the length of the front portion 541 along the axial direction to gradually increase as the radius increases so as to be bent, so that the fluid flows more smoothly; for example Fig. 9 Compared with the front part 541 at AA and BB, at AA: the radius is larger, the coordinate of L-Z2 along the axial direction is larger, which makes the front part 541 longer, and the curvature is set to be larger and the change is smoother.

[0097] In a preferred embodiment, if Figure 8, L-Z2 is curved and convex away from the front edge of the rear suspension support plate 52. In other embodiments, such as Figure 7 The trailing edge profile L-Z1 of the front portion 541 in the rear suspension support plate 52 may be arranged to be straight and inclined toward the outlet of the axial flow fan 1000.

[0098] In a preferred embodiment, if Figure 8 , Fig. 9 The front part 541 and the rear part 542 are connected, which can make the axial size of the rear suspension support plate 52 compact and facilitate demolding on both sides along the axial direction.

[0099] In a preferred embodiment, if Fig. 9 , the absolute value of the slope of the contour tangent of the windward surface 551 of the second part 522 in the equal radius surface keeps increasing gradually along the first direction, and the same is true for the leeward surface 552; in other embodiments, it can gradually increase or remain unchanged to form a natural draft angle to facilitate axial drafting. In the present invention, in the equal radius surface, the contour tangent takes the opposite directions of the Z direction and the W direction as the two-dimensional coordinate axis; the slope of the contour tangent is positive, that is, the angle between the tangent and the Z direction is positive; Fig. 9 Schematically shows the contour tangent line L1 of the point P2 on the windward surface 551 of the rear portion 542 on the surface of equal radius, and the slope of L1 is negative.

[0100] In a preferred embodiment, if Figure 8 The outer diameter of the rear mounting part 42 gradually decreases along the first direction, so that the surface shape of the rear mounting part 42 has a smooth transition, which is convenient for processing, especially for casting; further, the maximum radius of the rear mounting part 42 is set to be equal to the minimum radius r1 of the downstream end of the blade flow channel 6, and the diameter is the same as the blade flow channel 6, so that the fluid can flow smoothly from the blade assembly 2 to the rear mounting part 42, and then flow smoothly through the rear mounting part 42, thereby reducing the fluid flow power loss.

[0101] In a preferred embodiment, if Figure 8 The radius at the leading 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 channel 6, and is equal to the maximum radius of the rear mounting part 42, which facilitates the axial demolding of the front part 541.

[0102] In a preferred embodiment, if Fig.10 The slope of the tangent line L3 of the leeward surface 552 of the first part 521 at the contour trailing edge point P3 of the equal radius surface is negative, which facilitates the axial draft of the first part 521.

[0103] The multiple rear suspension support plates 52 provided in this embodiment can be cast together, such as Fig.10, the leeward side 552 of the upper rear suspension support plate 52 faces the windward side 551 of the lower rear suspension support plate 52, and the line L-S1 connecting the trailing edge point P3 of the leeward side 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 the parting line, and the slope of L-S1 at any point in the equal radius surface is positive, for example, the slope of the tangent line L4 at point P5 is positive; a mold is set upstream of L-S1, and the mold is pulled along the S1 direction, and S1 is opposite to the Z direction; another mold is set downstream of L-S1, and the mold is pulled along the S2 direction, and S2 is in the same direction as the Z direction; in this way, the outer branch part can be obtained; further, S1 and S2 can be set parallel to the axial direction. Further, in this embodiment, Fig. 9 The thickness of the inner branch part 532, i.e., the third part 523, gradually decreases along the first direction, and the absolute value of the slope of the contour tangent of the windward surface 551 and the leeward surface 552 in the equal radius surface gradually increases along the first direction. In other embodiments, it can gradually increase or remain unchanged to form a natural draft angle. The third part 523 can be cast together with the second part 522 and drafted along the S2 direction.

[0104] Example 3

[0105] The present embodiment provides an axial flow fan. The difference between the axial flow fan in the present embodiment and that in Embodiments 1 and 2 mainly lies in the different shape of the rear suspension support plate. The configuration of the shell, rotating shaft, blade assembly, and rear mounting parts in the present embodiment are the same as those in Embodiments 1 and 2, and specific reference may be made to Embodiments 1 and 2. Fig.11 is a schematic diagram of this embodiment.

[0106] like Fig.11 The slope of the tangent L5 of the leeward side 552 of the first part 521 at the trailing edge point P6 of the contour of the equal radius surface is positive. On the one hand, even if the fluid has a hysteresis angle, the flow direction of the fluid after passing through the point P6 is very close to the axial direction, so the residual speed is recovered to the maximum extent; on the other hand, the fluid is easily separated from the surface of the rear suspension support plate 52 at the trailing edge of the front part 541 due to the change in the surface of the rear suspension support plate 52. The slope of the tangent L5 at P6 is set to be positive, which facilitates the smooth transition of the contour of the front part 541 to the rear part 542, and inhibits the fluid from separating from the surface of the rear suspension support plate 52 after flowing through the trailing edge of the front part 541. Fig.11 L-Z3 drawn with a dotted line in the figure illustrates the approximate boundary between the front part 541 and the rear part 542.

[0107] The multiple rear suspension support plates 52 provided in this embodiment can be cast together, such as Fig.11, the leeward side 552 of the upper rear suspension support plate 52 faces the windward side 551 of the lower rear suspension support plate 52, and the line L-S2 connecting the trailing edge point of the leeward side 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 the parting line, and the slope of L-S2 at any point in the equal radius surface is positive; a mold is set upstream of L-S2, and the reverse rotational demolding is performed along the Z direction, and the demolding angle of the rotational demolding is between the absolute value of the angle between L5 and the axial direction and the absolute value of the angle between the tangent line of the point with the smallest slope on L-S2 and the axial direction, and S3 is a demolding direction in the demolding process; another mold is set downstream of L-S2, and the demolding is performed along the S4 direction, and S4 is in the same direction as the Z direction; in this way, the outer branch part can be obtained. Further, S4 can be set parallel to the Z direction.

[0108] Although the specific embodiments of the present invention are described above, it should be understood by those skilled in the art that this is only for illustration and the protection scope of the present invention is defined by the appended claims. Those skilled in the art may make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but these changes and modifications all fall within the protection scope of the present invention.

Claims

1. An axial flow fan, comprising: case; A rotating shaft is arranged in the housing; At least one blade assembly is arranged in the blade flow channel; The axial flow fan further comprises a rear suspension support plate and a rear mounting member arranged in the housing, the rear mounting member is arranged downstream of the rotating shaft and is rotatably connected to the rotating shaft, the rear suspension support plate is located downstream of the blade assembly and is fixed to the rear mounting member and the housing respectively; The rear suspension support plate has an outer branch portion with a radius greater than or equal to the minimum radius of the downstream end of the blade flow channel, and the rear suspension support plate has a front portion, which extends axially in a first direction toward the outlet of the axial flow fan and forms a leading edge of the rear suspension support plate. The windward surface and the leeward surface of the outer branch portion in the front portion are both curved and convex toward the leeward side of the rear suspension support plate, and the degree of curvature gradually increases in a second direction radially away from the rotating shaft of the axial flow fan.

2. The axial flow fan according to claim 1, characterized in that: The radii of the front part at the root and the tip are respectively equal to the minimum radius and the maximum radius of the downstream end of the blade flow channel.

3. The axial flow fan according to claim 1, characterized in that: The axial coordinate of the trailing edge of the leading portion gradually increases along the second direction.

4. The axial flow fan according to claim 1, characterized in that: The rear suspension support plate further comprises a rear portion, the rear portion extending along the first direction and forming a trailing edge of the rear suspension support plate, and the thickness of the outer branch portion in the rear portion gradually decreases along the first direction; Preferably, the absolute value of the slope of the contour tangent of the windward surface and / or the leeward surface of the outer branch part in the rear part in the equal radius surface remains unchanged or gradually increases along the first direction; and / or the front part and the rear part are connected.

5. The axial flow fan according to claim 1, characterized in that: The rear suspension support plate further includes an inner support portion whose radius is smaller than the minimum radius of the downstream end of the blade flow channel, and the rear mounting member is at least mounted on the inner support portion.

6. The axial flow fan according to claim 5, characterized in that: The thickness of the inner branch portion gradually decreases along the first direction, and the absolute value of the slope of the contour tangent of the windward surface and / or the leeward surface in the surface of equal radius remains unchanged or gradually increases along the first direction; and / or, the outer diameter of the rear mounting member gradually decreases along the first direction, and the maximum radius is equal to the minimum radius of the downstream end of the blade flow channel; And / or, 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 channel.

7. The axial flow fan according to claim 1, characterized in that: The number of the rear suspension support plates is multiple and they are evenly spaced around the axial direction. The average consistency of the rear suspension support plates is greater than or equal to 0.7; preferably, greater than or equal to 1.

8. The axial flow fan according to claim 1, characterized in that: The blade assembly includes moving blades installed on the rotating shaft and stationary blades installed on the housing; In the 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°; preferably, the outlet angle of the stationary blade is between 5° and 20°.

9. The axial flow fan according to claim 1, characterized in that: The slope of the tangent line of the leeward surface of the outer branch part in the front part at the contour trailing edge point in the equal radius surface is positive.

10. A method for manufacturing an axial flow fan, characterized in that: It is used to manufacture an axial flow fan according to any one of claims 1 to 8, wherein a plurality of rear suspension support plates are evenly arranged around the axial direction and cast, the leeward side of one of the two adjacent rear suspension support plates faces the windward side of the other rear suspension support plate, and a line connecting the trailing edge point of the leeward side of the front part of one rear suspension support plate and the leading edge point of the front part of the other rear suspension support plate in a surface of equal radius is a parting line, and a mold is provided upstream and downstream of the parting line respectively; The tangent slope of the contour of the leeward surface of the outer branch portion in the front portion in the equal radius surface gradually increases along the first direction, and the slope at the trailing edge point is negative, and the two molds are pulled out along the axial direction to obtain at least the outer branch portion of the rear suspension support plate; Or, the slope of the contour tangent of the leeward surface of the outer branch part in the front part within the equal radius surface gradually increases along the first direction, and the slope at the trailing edge point is positive, the mold arranged upstream of the parting line is axially rotated and drafted, and the mold arranged downstream of the parting line is axially drafted to obtain at least the outer branch part of the rear suspension support plate.

11. A range hood, characterized in that: It comprises the axial flow fan as claimed in any one of claims 1 to 9, the inlet of the axial flow fan is the inlet of the range hood or is connected to the inlet of the range hood, and the outlet of the axial flow fan is the outlet of the range hood or is connected to the outlet of the range hood.

Images