Axial flow fan and range hood comprising same

Abstract

The invention relates to the field of axial flow fans, and discloses an axial flow fan 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 piece 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 rotatably connected to the rear mounting piece; the rear suspension supporting plate is fixedly connected with the rear mounting piece and the shell, the thickness of the front portion of the rear suspension supporting plate is gradually increased in the first direction, at least the outer supporting portion of the front portion deviates towards the leeside, the contour tangent slope of the leeside on the equal-radius face is negative, and the leeside is provided with a bias flow section. The absolute value of the slope of the contour tangent line of the bias flow section on the equal-radius face is gradually reduced in the first direction, so that remaining speed recovery is conducted on incoming flow at the blade assembly, 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 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 a front portion, which extends axially in a first direction toward the outlet of the axial flow fan and forms a front edge of the rear suspension support plate. The thickness of the front portion gradually increases along the first direction. 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. In the front portion, at least the thickness of the windward side of the outer branch portion is less than the thickness of the leeward side. The slope of the contour tangent of the leeward side on the equal radius surface is negative. At least a part of the leeward surface is a deflection section. The absolute value of the slope of the contour tangent of the deflection section on the equal radius surface gradually decreases along the first direction.

[0011] In this solution, the fluid flows through the blade assembly and then flows to the rear suspension support plate. The thickness of the front portion of the rear suspension support plate gradually increases along the first direction, so that the fluid can be smoothly diverted at the front edge of the rear suspension support plate. The radius of the outer branch portion of the front portion 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 portion 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] On the one hand, by setting the thickness of the windward side of the outer branch part of the front part of the rear suspension support plate to be smaller than the thickness of the leeward side, the entire part is biased toward the leeward side, and after the fluid passes through the front part of the rear suspension support plate, the fluid can be guided to reduce the degree of deflection of the fluid relative to the axial direction;

[0013] On the other hand, the slope of the leeward surface contour tangent of the outer branch portion of the front portion of the rear suspension support plate is set to be negative, and a deflection section is set on the leeward surface of this portion, and the absolute value of the slope of the contour tangent of the deflection section gradually decreases, so that the contour tangent of the deflection section gradually approaches the axial direction, and the flow direction of the fluid passing through the front portion of the rear suspension support plate can be gradually deflected to approach the axial direction, further reducing the degree of deflection of the fluid relative to the axial direction;

[0014] Through these two designs, the degree of deflection of the fluid after flowing out of the blade assembly can be reduced, and the component velocity of the fluid flowing out of the blade assembly that is not parallel to the axial direction can be recovered, referred to as the recovery residual velocity, thereby reducing flow losses and noise.

[0015] Preferably, the profile of the deflection flow section on the surface of constant radius is at least second-order differentiable.

[0016] In the present solution, the arrangement is such that the surface of the deflection flow section is streamlined and changes smoothly, which, on the one hand, facilitates processing and, on the other hand, allows the fluid to flow smoothly.

[0017] Preferably, the slope of the contour tangent of the windward surface of at least the outer branch portion in the front portion on the surface of equal radius is positive or negative, and the absolute value of the slope remains unchanged or gradually decreases along the first direction.

[0018] In this solution, when the slope is positive, it is convenient to obtain the front part along the axial draft when the rear suspension support plate is cast, which facilitates processing.

[0019] When the slope is negative, the front part of the rear suspension support plate is more biased toward the leeward side, which can further reduce the degree of deflection of the fluid relative to the axial direction. Furthermore, when the front suspension support plate is set, and the front suspension support plate and the rear suspension support plate are set 180° rotationally symmetrically, the front part of the rear suspension support plate is equivalent to the rear part of the front suspension support plate. Such a setting can increase the pre-swirl degree of the incoming flow flowing to the front of the blade assembly and improve the pressure rise efficiency of the axial flow fan.

[0020] Preferably, the windward surface of at least the outer branch portion in the front portion has a straight line segment, and the absolute value of the profile slope of the straight line segment on the equal radius surface is less than or equal to 3°.

[0021] In this solution, a straight line segment is provided, which is convenient for processing. Further, the absolute value of the slope corresponding to the straight line segment is set to be less than or equal to 3°, which can ensure that the thickness of the outer branch part in the front part is large enough, thereby ensuring that the strength is high enough to be cast and drafted, and there is enough thickness space for setting the deflection section on the leeward side.

[0022] 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 rear portion gradually decreases along the first direction.

[0023] In the present solution, such an arrangement can make the thickness of the trailing edge of the rear suspension support plate small enough to reduce the wake of the fluid after it flows through the rear suspension support plate, thereby reducing flow loss and noise.

[0024] When the front suspension support plate and the rear suspension support plate are arranged 180° rotationally symmetrically, the rear portion of the rear suspension support plate is equivalent to the front portion of the front suspension support plate. Such an arrangement can make the thickness at the front edge of the front suspension support plate sufficiently small, and the thickness of the front portion of the front suspension support plate changes smoothly, thereby facilitating the diversion of the fluid at the front portion of the front suspension support plate.

[0025] Preferably, the axial length of the front portion is 0.25 to 0.5 times the axial length of the rear suspension support plate.

[0026] In the present solution, the arrangement is such that, on the one hand, the front part is long enough to have a good enough effect on deflecting the fluid; on the other hand, the front part is short enough to leave enough length space for the rear part. Even when the fluid flows from the front part to the rear part and separates from the surface of the rear suspension support plate, the rear part has enough length for the fluid to reattach to the surface of the rear suspension support plate, thereby suppressing the separation.

[0027] Preferably, the rear portion is arranged symmetrically about the axis.

[0028] In the present solution, such an arrangement facilitates processing on the one hand, and facilitates the fluid to flow out close to the axial direction on the other hand.

[0029] Preferably, the axial flow fan further comprises a front suspension support plate and a front mounting member arranged in the housing, the front mounting member being arranged upstream of the rotating shaft and rotatably connected to the rotating shaft, the front suspension support plate being located upstream of the blade assembly and being fixed to the front mounting member and the housing respectively;

[0030] The front suspension support plate and the rear suspension support plate are arranged in 180° rotational symmetry; and / or the front mounting member and the rear mounting member are arranged in 180° rotational symmetry.

[0031] In this solution, the front suspension support plate and the rear suspension support plate are arranged in 180° rotational symmetry. On the one hand, the front part of the rear suspension support plate corresponds to the rear part of the front suspension support plate, and the rear part of the front suspension support plate can deflect the incoming flow in front of the blade assembly, so that the fluid produces negative pre-rotation, thereby improving the efficiency of the axial flow fan; on the other hand, it is convenient to use the same process to manufacture the front suspension support plate and the rear suspension support plate, thereby reducing the processing cost.

[0032] The front mounting parts and the rear mounting parts are arranged in 180° rotational symmetry. On the one hand, it is convenient for the front mounting parts and the rear mounting parts to be processed and manufactured using the same process, thereby reducing processing costs; on the other hand, it is convenient for the front suspension support plate and the front mounting parts to be integrally formed and to be processed and manufactured using the same process as the rear suspension support plate and the rear mounting parts.

[0033] Preferably, the blade assembly comprises a moving blade mounted on the rotating shaft and a stationary blade mounted on the housing. 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 24°.

[0034] In the present solution, such an arrangement can ensure that after the fluid is deflected by the front suspension support plate, the pre-rotation degree of the incoming flow in front of the blade assembly is large enough, thereby improving the efficiency of the axial flow fan; it can also ensure that the rear suspension support plate has a good enough effect on recovering the residual velocity of the fluid flowing out of the blade assembly, and has a good enough effect on reducing flow losses and noise.

[0035] Preferably, the outlet angle of the stationary blade is between 0° and 18°.

[0036] Preferably, the windward surface of at least the outer branch portion in the front portion has a straight line segment, and the contour slope of the straight line segment on the equal radius surface is between 0° and 10°.

[0037] In the present solution, the rear suspension support plate is configured so that the thickness is sufficient to set up a deflection section, so that the absolute value of the slope of the contour tangent of the deflection section on the equal radius surface gradually decreases significantly along the first direction, thereby improving the deflection effect of the deflection section: for the rear suspension support plate, it can ensure that the residual velocity recovery effect of the fluid flowing out of the blade assembly is good enough to reduce flow loss and noise; for the front suspension support plate, it can ensure that the fluid generates a sufficiently large degree of pre-rotation before flowing to the blade assembly, thereby improving the efficiency of the axial flow fan.

[0038] Preferably, the axial length of the front portion is 0.15 to 0.6 times the axial length of the rear suspension support plate; more preferably, it is 0.3 to 0.55 times.

[0039] In this scheme, the arrangement is such that, on the one hand, the front part of the rear suspension support plate is long enough, the deflection effect on the fluid is good enough, and the residual speed recovery effect is good enough; accordingly, the rear part of the front suspension support plate makes the fluid pre-spin effect good enough. On the other hand, the front part of the rear suspension support plate is short enough to leave enough length space for the rear part. When the fluid flows from the front part to the rear part and separates from the surface of the rear suspension support plate, the rear part has enough length for the fluid to reattach to the surface of the rear suspension support plate, thereby suppressing the separation; accordingly, the front part of the front suspension support plate is long enough to facilitate the fluid to be smoothly diverted from the front part of the front suspension support plate.

[0040] 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.

[0041] 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.

[0042] Preferably, the outer diameter of the rear mounting member gradually decreases along the first direction, and the maximum outer diameter is equal to the minimum radius of the downstream end of the blade flow channel.

[0043] In this solution, 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; 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, reducing the fluid flow power loss.

[0044] 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.

[0045] 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.

[0046] Preferably, the rear suspension support plate further comprises a rear portion, the rear portion extends along the first direction and forms a trailing edge of the rear suspension support plate, the thickness of the rear portion gradually decreases along the first direction, the front portion and the rear portion are connected, and the rear suspension support plate is formed by casting;

[0047] The windward side and the leeward side of the outer branch part in the rear part have contour tangent slopes of negative and positive, respectively, on a surface of equal radius;

[0048] The slope of the contour tangent of the windward surface of the front part on the surface of equal radius is positive, and the boundary line between the front part and the rear part is used as the parting line, and the front part is obtained by axial drafting; preferably, the slopes of the contour tangent of the windward surface and the leeward surface of the inner branch part on the surface of equal radius are negative and positive respectively, and the inner branch part, the rear part of the outer branch part, and the rear mounting part are taken as the same casting module and obtained by axial drafting.

[0049] 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; more preferably, it is greater than or equal to 1.

[0050] In this solution, the rear suspension support plates are arranged densely enough to ensure that the residual speed recovery effect is good enough.

[0051] When the front suspension support plate and the rear suspension support plate are arranged to be rotationally symmetrical at 180 degrees, it can be ensured that the effect of the front suspension support plate on causing the fluid to pre-swirl is sufficiently good.

[0052] Preferably, the axial flow fan includes a plurality of stages of blade assemblies, the plurality of stages of blade assemblies are arranged in sequence along a first direction, and the blade assemblies include moving blades mounted on the rotating shaft and stationary blades mounted on the housing.

[0053] In this solution, the pressure rise and flow rate achieved by the first-stage blade assembly are realized in multiple stages, so that the sound power is expected to be reduced to 1 / K of the original. In this way, the axial flow fan can maintain a low noise level while ensuring that the aerodynamic performance of the axial flow fan is good enough. In addition, by designing a multi-stage blade assembly, each row of blades will block the noise transmission, play a certain reflection and absorption role, and further reduce the noise.

[0054] Preferably, all the moving blades have the same shape and size, and all the stationary blades have the same shape and size.

[0055] In this solution, the moving blades are set to have the same shape and size, and the stationary blades are set to have the same shape and size. No matter how many stages of blade components there are, the blade mold only needs two sets of molds for the moving blades and the stationary blades. The aerodynamic performance of the axial flow fan can be changed by increasing or decreasing the stages of blade components. It has good versatility and low processing cost.

[0056] Preferably, the material of the stationary blades and the moving blades is plastic or aluminum alloy. In this solution, the plastic or aluminum alloy material is relatively soft, and the wear on the mold can be reduced when the blades are manufactured by casting; the plastic or aluminum alloy material is relatively light, and the weight of the axial flow fan can be reduced when used in the axial flow fan.

[0057] Preferably, 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°; preferably, the outlet angle of the stationary blade is between 5° and 20°.

[0058] In this scheme, the outlet angles of the moving blades and the stationary blades are set so that the fluid flows through the stationary blades and then deflects relative to the axial direction before flowing to the next stage of moving blades, thereby improving the pressure rise efficiency of the axial flow fan. At the same time, the deflection section of the rear suspension support plate is set to deflect the fluid flowing out of the last stage of stationary blades, so that the fluid flow direction is close to the axial direction, thereby reducing flow losses.

[0059] When the front suspension support plate and the rear suspension support plate are set to be rotationally symmetrical at 180°, the deflection section in the rear suspension support plate corresponds to the windward surface of the rear part of the front suspension support plate in the front suspension support plate, which can deflect the fluid so that the fluid generates a negative pre-rotation angle after flowing through the front suspension support plate and then flows to the first-stage moving blades. On the one hand, the efficiency of the axial flow fan can be improved; on the other hand, when the blade assemblies of each stage are repeated, the front suspension support plate is set to deflect the incoming flow in front of the first-stage moving blades, so that the incoming flow conditions in front of the moving blades of each stage are close, which facilitates the basic consistency of the fluid flow conditions at the blade assemblies of each stage, so as to give full play to the performance of the repeated blade assemblies in the axial flow fan.

[0060] Preferably, the minimum radius and the maximum radius of the blade flow channel remain constant along the first direction;

[0061] Preferably, the axial length range of the rotating shaft completely covers the axial length range of the blade assembly, and the blade flow channel is formed between the inner surface of the shell and the outer surface of the rotating shaft.

[0062] In this solution, such a setting, on the one hand, is convenient for processing. On the other hand, when the blade assemblies of each stage are repeatedly arranged, the minimum radius and the maximum radius of the blade flow channel are set to be constant, so that the flow channel is stable, which facilitates the flow conditions in front of the moving blades or the stationary blades of each stage to be close, and facilitates the fluid flow conditions at the blade assemblies of each stage to be basically consistent, so as to give full play to the performance of the repeated blade assemblies in the axial flow fan.

[0063] Preferably, the number of stages of the blade assembly is K, and along the first direction: the first stage blade assembly, the second stage blade assembly, ..., the Kth stage blade assembly are arranged in sequence;

[0064] The blade assembly comprises a moving blade mounted on the rotating shaft and a stationary blade mounted on the housing. In a single-stage blade assembly, the moving blade is arranged upstream of the stationary blade, and the average spacing between the trailing edge of the i-th stage moving blade and the leading edge of the i-th stage stationary blade along the axial direction is drs_i, i=1, 2, ..., K; the average spacing between the trailing edge of the j-th stage stationary blade and the leading edge of the j+1-th stage moving blade along the axial direction is dsr_j, j=1, 2, ..., K-1;

[0065] As i increases, as j increases, drs_i and dsr_j change monotonically in the same direction;

[0066] When K=2, drs_1≠drs_K;

[0067] When K>2, drs_1≠drs_K and / or dsr_1≠dsr_K-1.

[0068] In this solution, in the axial flow fan, the larger the drs_i, the more evenly the fluid is mixed when it flows from the trailing edge of the same-level moving blade to the trailing edge of the same-level stationary blade, thereby improving the blade frequency abnormal sound and reducing the fluid flow noise. Similarly, the larger the dsr_j, the more evenly the fluid is mixed when it flows from the trailing edge of the previous-stage stationary blade to the leading edge of the next-stage moving blade, which can also improve the blade frequency abnormal sound and reduce the fluid flow noise.

[0069] As i increases and j increases, drs_i and dsr_j change monotonically in the same direction, and when K=2, drs_1≠drs_K, and when K>2, drs_1≠drs_K and / or dsr_1≠dsr_K-1, so that the closer to the inlet or outlet of the axial flow fan, the larger drs_i and dsr_j are:

[0070] On the one hand, when the setting is closer to the inlet of the axial flow fan, the larger drs_i and dsr_j are, the fluid is mixed more evenly at the blades closer to the inlet, and the noise generated by the fluid flow itself is smaller; and the noise generated by the fluid flow at the downstream blades, which is larger than that at the upstream blades, gradually weakens after being blocked by multiple rows of blades, thereby reducing the noise transmitted to the upstream; therefore, the noise in the upstream part of the axial flow fan, especially at the inlet, can be reduced.

[0071] On the second aspect, similar to the first aspect, when the setting is closer to the outlet of the axial flow fan, the larger drs_i and dsr_j are, the more evenly the fluid is mixed at the blades closer to the outlet, and the smaller the noise generated by the fluid flow itself; and the noise generated by the fluid flow at the upstream blades, which is relatively larger than that at the downstream blades, gradually weakens after being blocked by multiple rows of blades, thereby reducing the noise transmitted to the downstream; therefore, the noise in the downstream part of the axial flow fan, especially at the outlet, can be made smaller.

[0072] Thirdly, the axial dimension of the axial fan can be prevented from increasing while reducing the noise at the inlet or outlet of the axial fan; or, the axial dimension of the axial fan can be reduced while avoiding increasing the noise at the inlet or outlet of the axial fan.

[0073] Preferably, dsr_j≥drs_i, j=i; and / or, dsr_j>drs_(i+1), j=i;

[0074] In this solution, dsr_j>drs_i and / or dsr_j>drs_(i+1) are set to increase the axial spacing between the j-stage stationary blades and the j+1-stage moving blades, so that the fluid is mixed more evenly when flowing from the front-stage stationary blades to the leading edges of the rear-stage moving blades, thereby reducing the overall noise of the axial flow fan.

[0075] Preferably, the range of dsr_j / drs_i is between 1.1 and 1.5, and j=i.

[0076] 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.

[0077] 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, the outlet of the axial flow fan is the outlet of the range hood or is connected to the outlet of the range hood, drs_1≥drs_2≥…≥drs_K, dsr_1≥dsr_2≥…≥dsr_(K-1).

[0078] In this solution, the axial flow fan is used in the range hood. The inlet of the axial flow fan is closer to the user than the outlet. By setting drs_1≥drs_2≥…≥drs_K and dsr_1≥dsr_2≥…≥dsr_(K-1), the noise at the inlet of the axial flow fan can be reduced, thereby reducing the noise transmitted to the user.

[0079] The positive and progressive effects of the present invention are:

[0080] After the fluid flows through the blade assembly, it flows to the rear suspension support plate. The thickness of the front part of the rear suspension support plate gradually increases along the first direction, so that the fluid can be smoothly diverted at the front edge of the rear suspension support plate. 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:

[0081] On the one hand, by setting the thickness of the windward side of the outer branch part of the front part of the rear suspension support plate to be smaller than the thickness of the leeward side, the entire part is biased toward the leeward side, and after the fluid passes through the front part of the rear suspension support plate, the fluid can be guided to reduce the degree of deflection of the fluid relative to the axial direction;

[0082] On the other hand, the slope of the leeward surface contour tangent of the outer branch portion of the front portion of the rear suspension support plate is set to be negative, and a deflection section is set on the leeward surface of this portion, and the absolute value of the slope of the contour tangent of the deflection section gradually decreases, so that the contour tangent of the deflection section gradually approaches the axial direction, and the flow direction of the fluid passing through the front portion of the rear suspension support plate can be gradually deflected to approach the axial direction, further reducing the degree of deflection of the fluid relative to the axial direction;

[0083] Through these two designs, the degree of deflection of the fluid after flowing out of the blade assembly can be reduced, and the component velocity of the fluid flowing out of the blade assembly that is not parallel to the axial direction can be recovered, referred to as the recovery residual velocity, thereby reducing flow losses and noise.

[0084] The front suspension support plate and the rear suspension support plate are arranged in 180° rotational symmetry. On the one hand, the front part of the rear suspension support plate corresponds to the rear part of the front suspension support plate, and the rear part of the front suspension support plate can deflect the incoming flow in front of the blade assembly, so that the fluid produces negative pre-rotation, thereby improving the efficiency of the axial flow fan; on the other hand, it is convenient to use the same process for the front suspension support plate and the rear suspension support plate to reduce the processing cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0085] Figure 1 is a schematic diagram of a range hood according to Embodiment 1;

[0086] Figure 2 This is an external schematic diagram of the axial flow fan of Example 1;

[0087] Figure 3 This is a schematic diagram of the interior of the axial flow fan of Example 1;

[0088] Figure 4 This is a meridian view of the axial flow fan of Example 1;

[0089] Figure 5 This is a schematic diagram of an equal radius surface of the axial flow fan of Example 1;

[0090] Figure 6 This is a schematic diagram of the rear mounting member and the rear suspension support plate of Example 1;

[0091] Figure 7 This is a schematic diagram of the front mounting member and the front suspension support plate of Example 1;

[0092] Figure 8 This is a schematic diagram of the rear suspension support plate of Example 1;

[0093] Fig. 9 This is a meridian view of the rear suspension support plate of the axial flow fan of Example 1;

[0094] Fig.10 This is a meridian view of the front suspension support plate of the axial flow fan of Example 1;

[0095] Fig.11 Schematic diagram of the outer support portion of the rear suspension support plate of Example 1 on a surface of equal radius, and a schematic diagram of the corresponding portion of the front suspension support plate;

[0096] Fig.12 It is a schematic diagram of the inner support portion of the rear suspension support plate of Example 2 on a surface of equal radius;

[0097] Fig.13 This is a meridian view of the rear suspension support plate of the axial flow fan of Example 2;

[0098] Fig.14 Schematic diagram of the drafting of the rear suspension support plate on the equal radius surface in Example 2;

[0099] Fig.15 Schematic diagram of the outer support portion of the rear suspension support plate of Example 3 on a surface of equal radius, and a schematic diagram of the corresponding portion of the front suspension support plate;

[0100] Fig.16 Schematic diagram of the demoulding of the rear suspension support plate on the equal radius surface in Example 3;

[0101] Fig.17 This is a meridian view of the rear suspension support plate of the axial flow fan in other embodiments.

[0102] Description of reference numerals:

[0103] Axial fan 1000;

[0104] Shell 1, front shell 11, rear shell 12;

[0105] Blade assembly 2;

[0106] Moving blade 21, first-stage moving blade 211, second-stage moving blade 212, third-stage moving blade 213;

[0107] Stationary blade 22, first-stage stationary blade 221, second-stage stationary blade 222, third-stage stationary blade 223;

[0108] Axis 3;

[0109] Mounting member 4, front mounting member 41, rear mounting member 42;

[0110] Suspension support plate 5;

[0111] Front suspension support plate 51, first portion 511, second portion 512, third portion 513;

[0112] The rear suspension support plate 52, the fourth portion 521, the fifth portion 522, the sixth portion 523, the deflection section 524, and the straight section 525;

[0113] An outer branch portion 531 and an inner branch portion 532;

[0114] Pre-part 541, post-part 542;

[0115] Windward side 551, leeward side 552;

[0116] A first pouring part 561 and a second pouring part 562;

[0117] Blade flow channel 6;

[0118] Fume hood 2000, housing 3000;

[0119] Range hood 10000. DETAILED DESCRIPTION

[0120] The present invention is further described below by way of examples, but the present invention is not limited to the scope of the examples.

[0121] Example 1

[0122] This embodiment provides a range hood, Figure 1-Figure 11 It is a structural schematic diagram of this embodiment.

[0123] 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.

[0124] 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.

[0125] In a preferred embodiment, the inner diameter of the outlet of the axial flow fan 1000 is between 160 mm and 220 mm, so that the inner diameter of the outlet of the axial flow fan 1000 is close to the inner diameter of the commonly used universal smoke pipe, thereby facilitating the connection between the outlet of the axial flow fan 1000 and the universal smoke pipe. Further, the inner diameter of the outlet of the axial flow fan 1000 is set between 175 mm and 185 mm, so that the inner diameter of the outlet of the axial flow fan 1000 is close to the inner diameter of most universal smoke pipes, further improving the convenience of connecting the axial flow fan 1000 and the smoke pipe.

[0126] 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.

[0127] like Figure 2-Figure 5 The 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.

[0128] 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 A blade flow channel 6 is formed between the inner surface of the shell 1 and the surfaces of other parts of the shell 1 except the blade assembly 2. In this embodiment, the blade flow channel 6 is specifically formed by the inner surface of the shell 1 and the outer surface of the rotating shaft 3; the blade assembly 2 is arranged in the blade flow channel 6.

[0129] 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 , Figure 7 The three-dimensional diagram of the hanging support plate 5 and the corresponding mounting member 4 is shown. The mounting member 4 and the hanging 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.

[0130] 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.

[0131] In this embodiment, the pressure rise and flow rate achieved by the first-level blade assembly 2 are realized by using the K-level, so that the sound power is expected to be reduced to the original 1 / K. In this way, the axial flow fan 1000 can maintain a low noise level while ensuring that the aerodynamic performance of the axial flow fan 1000 is good enough. In addition, by designing the K-level blade assembly 2, each row of blades will block the transmission of noise, play a certain reflection and absorption role, thereby further reducing noise. Applying the K-level axial flow fan 1000 to the range hood 10000 can make the range hood 10000 have good aerodynamic performance and low noise.

[0132] The consistency is a well-known concept, and the blade consistency can be understood as the chord length of the blade / the distance between two adjacent blades in a single row of blades. In a preferred embodiment, the maximum consistency of the single row of stationary blades 22 and the single row of moving blades 21 can be set to be less than or equal to 1.8, so that the blades in the single row of blades are arranged sparsely enough to facilitate demolding when the blades are cast. When the maximum consistency of the single row of blades is set to be less than or equal to 1.4, the effect is better.

[0133] In a preferred embodiment, such as the present embodiment, the moving blades 21 are set to have the same shape and size, and the stationary blades 22 are set to have the same shape and size, forming a repeated blade assembly 2. No matter how many levels of the blade assembly 2 there are, the blade mold only needs two sets of molds for the moving blades 21 and the stationary blades 22. The aerodynamic performance of the axial flow fan 1000 can be changed by increasing or decreasing the number of levels of the blade assembly 2, which has good versatility and low processing cost. Furthermore, the material of the stationary blades 22 and the moving blades 21 can be made of softer materials such as plastic or aluminum alloy, which can reduce the wear on the mold when the blades are manufactured by casting; the use of lighter materials such as plastic or aluminum alloy in the axial flow fan 1000 can reduce the weight of the axial flow fan 1000.

[0134] In other embodiments, two, three or more stages of blade assemblies 2 may be provided in the axial flow fan 1000. The aerodynamic performance of the range hood 10000 may be improved by increasing the number of stages of the blade assemblies 2, and the radial dimension of the axial flow fan 1000 may be made smaller to reduce the space occupied by the axial flow fan 1000 in the X and Y directions in the kitchen.

[0135] In a preferred embodiment, if Figure 4 The inner diameter of the shell 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 remain constant, forming a stable blade flow channel 6, which facilitates the approach of the incoming flow conditions in front of each level of moving blades 21 or each level of stationary blades 22, and facilitates the basic consistency of the fluid flow conditions at each level of blade assemblies 2, so as to give full play to the performance of the repeated blade assemblies 2 in the axial flow fan 1000.

[0136] In a preferred embodiment, the hub ratio of the blade flow channel 6 is r1 / r2, ranging from 0.4 to 0.8, so that the hub ratio is large enough, so that the blade height is small enough, so that the curvature of the blade tip and the blade root can be set smaller, the fluid flows smoothly, and the noise is small; the hub ratio is small enough, so that the blade height is large enough, so that the channel when the fluid flows through the blade is large enough, and the flow rate is large enough.

[0137] 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.

[0138] 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 of the moving blade 21, which is convenient for generating negative pre-rotation and can improve the pressure rise efficiency of the axial flow fan 1000. The fluid flowing out from the last stage of the stationary blade 22 has a negative residual velocity. In the present invention, a rear suspension support plate 52 is provided to recover the residual velocity of the fluid, thereby reducing the flow loss and ensuring that the efficiency of the axial flow fan is sufficiently high. 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.

[0139] In a preferred embodiment, such as the present embodiment, the front suspension support plate 51 and the rear suspension support plate 52 are arranged 180° rotationally symmetrically, and have the same shape and size. It can be understood that the rear suspension support plate 52 can be installed on the front mounting member 41 as the front suspension support plate 51 after being rotated 180°. The front mounting member 41 and the rear mounting member 42 are also arranged 180° rotationally symmetrically. Such an arrangement facilitates the two suspension support plates 5 and the two mounting members 4 to be manufactured using the same process, thereby reducing the processing cost.

[0140] like Figure 8 , Fig. 9The 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 plane LR 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 on at least 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 on 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.17 In the corresponding embodiment, the rear suspension support plate 52 is not provided with the inner support portion 532 .

[0141] like Figure 8 The rear suspension support plate 52 has a front portion 541 with a gradually increasing thickness T and a rear portion 542 with a gradually decreasing thickness along the Z direction. The thickness T is marked as Fig.11 The front edge of the rear suspension support plate 52 is formed at the front portion 541, and the rear edge of the rear suspension support plate 52 is formed at the rear portion 542. Figure 8 The plane indicated by LZ in the figure is the approximate boundary between the front part 541 and the rear part 542. After the fluid flows through the blade assembly 2, it flows to the rear suspension support plate 52. The thickness of the front part 541 of the rear suspension support plate 52 gradually increases along the Z direction, so that the fluid can be smoothly diverted at the front edge of the rear suspension support plate 52. The thickness of the rear part 542 of the rear suspension support plate 52 gradually decreases along the Z direction, so as to reduce the wake of the fluid after it flows through the rear suspension support plate 52, thereby reducing flow loss and noise. In addition, the front suspension support plate 51 and the rear suspension support plate 52 are 180° rotationally symmetrical. The rear part 542 of the rear suspension support plate 52 is equivalent to the front part of the front suspension support plate 51. The thickness of the rear part 542 gradually decreases along the Z direction, so that the thickness at the front edge of the front suspension support plate 51 is sufficiently small, and the thickness of the front part of the front suspension support plate 51 changes smoothly, so that the fluid can be diverted at the front part of the front suspension support plate 51.

[0142] Table 1. Division of the 5 parts of the suspension support plate

[0143] Rear suspension support plate 52 middle part Abbreviation Corresponding part in the front suspension support plate 51 The front part 541 in the outer branch part 531 Part IV 521 Part II 512 The rear part 542 of the outer branch part 531 Part 522 Part I511 Inner branch 532 Part VI 523 Part III 513

[0144] For ease of understanding, the present invention divides the various parts of the front suspension support plate 51 and the rear suspension support plate 52, as shown in Table 1 for details. Fig. 9The dotted lines in the figure indicate the approximate boundaries of the fourth part 521, the fifth part 522, and the sixth part 523; Fig.10 The dotted lines in the figure indicate the approximate boundaries among the first part 511 , the second part 512 , and the third part 513 .

[0145] Fig.11 The diagram shows the shape of the outer support portion 531 of the rear suspension support plate 52 on a constant radius surface, where the constant 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 countless constant radius surfaces.

[0146] like Figure 8 , Fig. 9 , Fig.11 , the thickness T1 of the front part 541 of the rear suspension support plate 52 on the windward side 551 is smaller than the thickness T2 on the leeward side 552, so that the front part 541 as a whole is biased toward the leeward side 552. In this way, when the fluid from the blade assembly 2 has a negative residual velocity, it flows through the front part 541, and the front part 541 can guide the fluid to reduce the relative axial deflection degree of the fluid, so as to recover the residual velocity of the fluid, reduce flow losses, and improve the efficiency of the axial flow fan 1000. Furthermore, due to the improvement in 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, and the noise can be reduced. Fig.11 The imaginary line L-T1 passing through the leading edge point P1-1 of the front portion 541 and parallel to the Z direction can be understood as the thickness boundary between the windward side 551 and the leeward side 552 of the rear suspension support plate 52.

[0147] like Fig.11 , the slope of the contour tangent of the leeward surface 552 in the front part 541 on the equal radius surface is negative, and is in the same direction as the incoming flow with negative residual velocity. At least part of the leeward surface 552 is a deflection section 524. The absolute value of the slope of the contour tangent of the deflection section 524 on the equal radius surface gradually decreases along the Z direction, so that the contour tangent of the deflection section 524 gradually approaches the axial direction. When the fluid passes through the front part 541, the flow direction can be gradually deflected to approach the axial direction, further reducing the degree of deflection of the fluid relative to the axial direction, and recovering the residual velocity of the fluid to a greater extent. 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.11 Schematically shows the contour tangent line L1 of the point P2 on the leeward surface 552 of the front part 541 on the equal radius surface, and the slope of L1 is negative.

[0148] like Fig.11The front part 541 of the rear suspension support plate 52 corresponds to the rear part of the front suspension support plate 51. The front part 541 can recover the negative residual velocity of the fluid. The front part 541 is rotated 180 degrees to obtain the rear part of the front suspension support plate 51, which can make the fluid produce negative pre-rotation before flowing to the frontmost moving blade 21, so as to improve the efficiency of the axial flow fan 1000; the position of the deflection section 524 of the rear suspension support plate 52 in the front suspension support plate 51 corresponds to the windward surface 551 located in the rear part. The slope of the contour tangent in the front suspension support plate 51 is negative and the absolute value of the slope gradually increases along the Z direction, which can increase the degree of pre-rotation of the fluid and further improve the efficiency of the axial flow fan 1000. When the blade assembly 2 in the axial flow fan 1000 is repeatedly arranged, for example, in the present embodiment, and a front suspension support plate 51 is arranged upstream of all the blade assemblies 2, the incoming flow in front of the upstreammost moving blade 21 can be deflected, so that the incoming flow in front of the moving blades 21 of each stage is close, so that the fluid flow conditions at the blade assemblies 2 of each stage are basically consistent, so as to give full play to the performance of the repeated blade assemblies 2 in the axial flow fan 1000.

[0149] 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.

[0150] Furthermore, when the front suspension support plate 51 and the rear suspension support plate 52 are set to be 180° rotationally symmetrical, considering the performance of the front suspension support plate 51, when the outlet angle β4 of the stationary blade 22 is set between 0° and 24°, it can ensure that the pre-swirl degree of the incoming flow in front of the first-stage moving blade 211 is large enough through the front suspension support plate 51; and it can also ensure that the rear suspension support plate 52 has a good enough effect of recovering the residual velocity of the fluid flowing out of the most downstream stationary blade 22; thereby making the efficiency of the axial flow fan 1000 high enough; at the same time, it can also ensure that the performance of the repeated blade assembly 2 is good. The effect is better when the outlet angle of the stationary blade 22 is between 0° and 18°.

[0151] In a preferred embodiment, the profile of the deflection flow section 524 on the equal radius surface is at least second-order differentiable and streamlined, so that the surface of the deflection flow section 524 changes smoothly, which is easy to process on the one hand, and makes the fluid flow smooth on the other hand.

[0152] In a preferred embodiment, if Fig.11 The slope of the contour tangent of the windward surface 551 in the front part 541 on the equal radius surface is positive, and the absolute value of the slope remains unchanged or gradually decreases along the Z direction, so that when the rear suspension support plate 52 is cast, the front part 541 can be obtained by axial drafting, which is convenient for processing.

[0153] In a preferred embodiment, if Fig.11 The windward surface 551 of the front part 541 has a straight line segment 525, which facilitates processing. Furthermore, the absolute value of the profile slope of the straight line segment 525 on the equal radius surface is between 0° and 10°. Under the condition that the thickness of the rear suspension support plate 52 remains unchanged, such a setting can make T1 small enough, so that T2 is large enough to set the deflection section 524 on the leeward surface 552, thereby improving the effect of recovering the residual velocity of the fluid. Fig.11 The tangent slope at point P3-1 on the straight line segment 525 is positive. Further, when the absolute value of the contour slope of the straight line segment 525 on the equal radius surface is set between 0° and 3°, the effect is better. It can be understood that the limitation on the structural shape in the present invention allows for a preset range of processing errors; for example, Fig.11 In the figure, the front edge of the front part 541 is a continuous smooth curve, and the axial length of this part accounts for a small proportion of the total length of the front part 541 and can be ignored, so it is considered that the windward surface 551 of the front part 541 belongs to the straight line segment 525.

[0154] In a preferred embodiment, if Fig.11 , the axial length of the front part 541 is 0.25 to 0.5 times the axial length of the rear suspension support plate 52. It can be understood that the length comparison is carried out on the same equal radius surface. With such a configuration, on the one hand, the front part 541 is long enough and the residual speed recovery effect is good enough; on the other hand, the front part 541 is short enough to leave enough length space for the rear part 542. When the fluid flows from the front part 541 to the rear part 542 and separates from the surface of the rear suspension support plate 52, the rear part 542 has enough length for the fluid to reattach to the surface of the rear suspension support plate 52, thereby suppressing the separation.

[0155] When the front suspension support plate 51 and the rear suspension support plate 52 have the same shape and size, the axial length of the front portion 541 can be set to be 0.15 to 0.6 times the axial length of the rear suspension support plate 52, so as to take into account the performance of the front suspension support plate 51, so that the rear portion of the front suspension support plate 51 of the same shape is long enough to suppress separation and produce a good pre-spin effect. In this case, when the axial length of the front portion 541 is set to be 0.3 to 0.55 times the axial length of the rear suspension support plate 52, the effect is better.

[0156] In a preferred embodiment, if Fig.11 The rear portion 542 is symmetrically arranged about the axial direction. On the one hand, it is convenient for processing; on the other hand, it is convenient for the fluid to flow out close to the axial direction.

[0157] In a preferred embodiment, the number of the front suspension support plates 51 and the number of the rear suspension support plates 52 are the same, both are multiple, and are evenly spaced around the axial direction, as shown in FIG. Figure 3 Furthermore, the average consistency of the two suspension support plates 5 is greater than or equal to 0.7, so that the suspension support plates 5 are arranged densely enough to ensure that the front suspension support plate 51 produces pre-spin and the rear suspension support plate 52 recovers the residual speed sufficiently. The average consistency can be understood as the average consistency at different radii. When the average consistency of the suspension support plates 5 is set to be greater than or equal to 1, the effect is better.

[0158] like Figure 4 , the average spacing between the trailing edge of the i-th stage moving blade 21 and the leading edge of the i-th stage stationary blade 22 is drs_i, i=1, 2, ..., K. As i increases, drs_i decreases, that is, the closer to the inlet of the axial flow fan 1000, the larger drs_i. K=3, the corresponding drs_i are drs_1, drs_2, drs_3, drs_1>drs_2>drs_3. The average spacing can be understood as the average value of the spacing at different radii. The spacing at a certain blade height is simplified and marked as the average spacing in the figure.

[0159] like Figure 6 , the average spacing along the Z direction between the trailing edge of the j-th stationary blade 22 and the leading edge of the j+1-th moving blade 21 is dsr_j, j=1, 2, ..., K-1, as j increases, dsr_j decreases, that is, the closer to the inlet of the axial flow fan 1000, the larger dsr_j. K=3, dsr_j are dsr_1 and dsr_2 respectively, and dsr_1>dsr_2. In other embodiments, if a two-stage blade assembly 2 is provided, corresponding to one dsr_j, i.e., dsr_1, it can be considered that dsr_j decreases or increases as the number of stages increases.

[0160] In the range hood 10000, the inlet of the range hood 10000 is generally closer to the user than the outlet. The noise generated closer to the inlet of the axial flow fan 1000 has a greater impact on the user. The larger drs_i is, the more evenly the fluid is mixed when it flows from the trailing edge of the moving blade 21 of the same level to the trailing edge of the stationary blade 22 of the same level, thereby improving the blade frequency abnormal sound and reducing the fluid flow noise. The closer the inlet of the range hood 10000 is to the axial flow fan 1000, the larger drs_i and dsr_j are. On the one hand, the airflow is mixed more evenly at the blades closer to the inlet of the axial flow fan 1000, the smaller the noise generated by the airflow itself, and the smaller the noise transmitted to the user. On the other hand, although the closer the outlet of the axial flow fan 1000 is, the smaller drs_i and dsr_j are, so that the noise generated at the downstream blades is greater than the noise generated at the upstream blades, the closer to the outlet of the axial flow fan 1000, the smaller the noise generated at the downstream blades. The farther away from the user, the smaller the impact of the generated noise on the user, and the closer to the outlet of the axial flow fan 1000, the greater the noise generated by the airflow. When it is transmitted to the inlet of the axial flow fan 1000, it needs to pass through more rows of blades to block, so that the noise generated by the downstream blades gradually weakens in the process of transmitting upstream, thereby reducing the noise transmitted to the user; combining these two aspects, the noise in the upstream part of the axial flow fan 1000, especially at the inlet, can be made smaller, thereby reducing the noise transmitted from the range hood 10000 to the user.

[0161] If the noise level at the inlet of the axial flow fan 1000 is kept consistent, compared with the solution of the same drs_i and the same dsr_j, in this embodiment, by setting the closer to the inlet of the axial flow fan 1000, the larger the drs_i and the larger the dsr_j, it is convenient to reduce the axial size of the axial flow fan 1000 and make the structure compact. If the axial size of the axial flow fan 1000 is kept the same, compared with the solution of the same drs_i and the same dsr_j, in this embodiment, by setting the closer to the inlet of the axial flow fan 1000, the larger the drs_i and the larger the dsr_j, the noise at the inlet of the axial flow fan 1000 can be greatly reduced. In the range hood 10000, generally, the inlet of the range hood 10000 is closer to the user than the outlet, so that the upstream blade assembly 2 in the axial flow fan 1000 is closer to the user. By setting drs_i to decrease and dsr_j to decrease, the noise transmitted to the user by the axial flow fan 1000 can be smaller, while taking into account the compact structure performance of the axial flow fan 1000, so that the range hood 1000 can take into account both the compact structure and the low noise performance.

[0162] In other embodiments, it can be set that as i increases and as j increases, drs_i and dsr_j change monotonically in the same direction; when K=2, drs_1≠drs_K; when K>2, drs_1≠drs_K and / or dsr_1≠dsr_K-1, that is, the effect of reducing the noise at the inlet or outlet of the axial flow fan 1000 can be achieved, or the axial size and noise reduction performance of the axial flow fan 1000 can be taken into account. For example, drs_1≥drs_2...≥drs_K, and dsr_1≥dsr_2...≥drs_K-1; or drs_1≤drs_2...≤drs_K, and dsr_1≤dsr_2...≤drs_K-1, can be considered that drs_i and dsr_j change monotonically in the same direction.

[0163] In other embodiments, the axial flow fan 1000 of this embodiment or other embodiments may be applied to other scenarios besides the range hood 10000.

[0164] In other embodiments, when the inlet of the axial flow fan 1000 is closer to the user than the outlet, drs_1≥drs_2≥…≥drs_K, dsr_1≥dsr_2≥…≥dsr_(K-1) can be set. When K>2, drs_1≠drs_K and / or dsr_1≠dsr_K-1, that is, the noise at the inlet of the axial flow fan 1000 can be reduced, thereby reducing the noise transmitted to the user, or the axial size and noise reduction performance of the axial flow fan 1000 can be taken into account; further, setting drs_1>drs_2>…>drs_K, dsr_1>dsr_2>…>dsr_(K-1) will have a better effect.

[0165] In other embodiments, when the outlet of the axial flow fan 1000 is closer to the user than the inlet, such as air supply equipment such as air conditioners and blowing devices, drs_1≤drs_2≤…≤drs_K, dsr_1≤dsr_2≤…≤dsr_(K-1) can be set. When K=2, drs_1≠drs_K; when K>2, drs_1≠drs_K and / or dsr_1≠dsr_K-1, so that the noise at the outlet of the axial flow fan 1000 is smaller, thereby reducing the noise transmitted to the user; further, setting drs_1<drs_2<…<drs_K, dsr_1<dsr_2<…<dsr_(K-1) has a better effect.

[0166] In other embodiments, a first-stage stationary blade 221 or a moving blade 21 may have only one row of blades; or, a single-stage moving blade 21 or a single-stage stationary blade 22 may be formed by connecting multiple rows of blades in series. In this case, for a first-stage blade, the leading edge of the first row of blades in the multiple rows of blades is considered to be the leading edge of the blade of that stage, and the trailing edge of the last row of blades is considered to be the trailing edge of the blade of that stage.

[0167] In a preferred embodiment, by setting dsr_j>drs_i, j=i, that is, the axial spacing between the j-stage stationary blade 22 and the j+1-stage moving blade 21 is greater than the axial spacing between the j-stage moving blade 21 and the j-stage stationary blade 22; and / or, setting dsr_j>drs_(i+1), j=i, that is, the axial spacing between the j-stage stationary blade 22 and the j+1-stage moving blade 21 is greater than the axial spacing between the j+1-stage moving blade 21 and the j+1-stage stationary blade 22; both can increase the axial spacing between the j-stage stationary blade 22 and the j+1-stage moving blade 21, so that the fluid is mixed more evenly when flowing from the front-stage stationary blade 22 to the leading edge of the rear-stage moving blade 21, thereby making the overall noise of the axial flow fan 1000 smaller.

[0168] In a preferred embodiment, j=i, and the range of dsr_j / drs_i is between 1 and 1.4, which can make the values ​​of dsr_j and drs_i large enough to reduce the noise of the axial flow fan 1000, and can also make dsr_j and drs_i small enough to avoid the axial dimension of the axial flow fan 1000 being too large.

[0169] Example 2

[0170] 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 shapes of the suspension support plates. The configurations of the shell, rotating shaft, blade assembly, and mounting parts in the present embodiment are the same as those in Embodiment 1, and specific reference may be made to Embodiment 1. Figure 12-14 is a schematic diagram of this embodiment.

[0171] In this embodiment, the front suspension support plate 51 and the rear suspension support plate 52 are 180° rotationally symmetrical. In this embodiment, the shape of the outer support portion 531 of the rear suspension support plate 52 is the same as that of the embodiment 1, and the shape of the inner support portion 532 of the rear suspension support plate 52 is different from that of the embodiment 1; in the embodiment 1, the inner support portion 532, i.e., the third portion 513, one part belongs to the front portion 541, and the other part belongs to the rear portion 542, i.e., the thickness of the inner support portion 532 gradually increases and then gradually decreases along the Z direction; Fig.12 In this embodiment, the thickness of the inner support portion 532 of the rear suspension support plate 52 gradually decreases along the Z direction, and the absolute value of the slope of the contour tangent of the windward surface 551 and the leeward surface 552 of the inner support portion 532 in the equal radius surface gradually increases. In other embodiments, it may remain unchanged or gradually increase to form a natural draft angle. Fig.12 The middle dotted line L2 is the outline of the rear mounting member 42. Fig.13 , Fig.14 , Table 2, the fifth part 522 and the sixth part 523 of the rear suspension support plate 52 can be cast together to form the second casting part 562. Fig.14, taking the dividing line L-S1 between the front part 541 and the rear part 542 as the parting line, a mold is placed on the left side of L-S1 between the two rear suspension support plates 52, and the mold is pulled out along the S1 direction to cast and form the first casting part 561; another mold is placed on the right side of L-S2, and the mold is pulled out along the S2 direction to cast and form the second casting part 562; S1 and S2 are along the axial direction; further, it can be set to be parallel to the Z direction.

[0172] Table 2: Division of casting locations of hanging support plate 5

[0173]

[0174] Further, such as Fig.13 , the outer diameter of the rear mounting part 42 gradually decreases along the Z 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 radius at the leading edge P4 of the root of the rear suspension support plate 52 is the same as the maximum outer diameter of the rear mounting part 42, both of which are the minimum radius r1 at the downstream end of the blade flow channel 6, which is convenient for the rear suspension support plate 52 and the rear mounting part 42 to be processed and formed as one piece. The rear suspension support plate 52 and the rear mounting part 42 provided in this embodiment can be cast and formed as one piece. In addition, the upstream end of the rear mounting part 42 has the same diameter as the blade flow channel 6, which can make the fluid flow smoothly from the blade assembly 2 to the rear mounting part 42, and then flow smoothly through the rear mounting part 42, reducing the fluid flow power loss.

[0175] Example 3

[0176] 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 shape of the suspension support plate. The configuration of the shell, rotating shaft, blade assembly, and mounting parts in the present embodiment are the same as those in Embodiment 2. For details, please refer to Embodiments 1 and 2. Figure 15-16 is a schematic diagram of this embodiment.

[0177] In this embodiment, the front suspension support plate 51 and the rear suspension support plate 52 are 180° rotationally symmetrical. In this embodiment, the shape of the inner support portion 532 of the rear suspension support plate 52 is the same as that of the embodiment 2, and the shape of the outer support portion 531 of the rear suspension support plate 52 is different from that of the embodiment 2; in this embodiment, the front portion 541 of the outer support portion 531 of the rear suspension support plate 52, i.e., the fourth portion 521, has a windward surface 551 with a straight line segment 525, and the slope on the equal radius surface is negative and the absolute value of the slope remains unchanged along the Z direction, for example Fig.15 The tangent slope at the point P3-2 shown in the figure is negative. In other embodiments, the tangent slope of the contour of the windward surface 551 of the fourth part 521 on the equal radius surface can be set to be negative and the absolute value of the slope remains unchanged or gradually decreases. Fig.15In the figure, the imaginary line L-T2 passing through the leading edge point P1-2 of the front part 541 and parallel to the axial direction can be understood as the boundary of the thickness between the windward side 551 and the leeward side 552 of the rear suspension support plate 52. The thickness on the windward side 551 of the front part 541 is missing, and the thickness T1 can be considered to be a negative value. At this time, it can be considered that T1<T2, and the thickness T of the front part 541 is equal to the thickness T2 on the leeward side.

[0178] In this embodiment, the tangent slope of the windward surface 551 of the fourth part 521 is set to be negative on the equal radius surface, and the front part 541 of the rear suspension support plate 52 is biased to a greater extent toward the leeward surface 552, which can further improve the effect of the fourth part 521 on recovering the residual velocity of the incoming flow. The front suspension support plate 51 and the rear suspension support plate 52 are arranged in 180° rotational symmetry, and the fourth part 521 relative to the second part 512 of the front suspension support plate 51 can improve the degree to which the second part 512 causes the fluid to pre-swirl.

[0179] like Fig.16 The rear suspension support plate 52 is cast in two molds, with L-S2 as the parting line. Fig.16 The trailing edge point of the middle upper rear suspension support plate 52 and the leading edge point of the lower rear suspension support plate 52 are located at both ends of L-S2; between the two rear suspension support plates 52, a mold is placed on the left side of L-S2, and the mold is pulled out by axial rotation, and S3 is an angle diagram in the demolding process; another mold is placed on the right side of L-S2, and the mold is pulled out along the S4 direction, and S4 is along the axial direction; further, S4 can be set parallel to the Z direction.

[0180] In general, the axial flow fan 1000 provided by the present invention has the following advantages:

[0181] 1. The axial flow fan 1000 is small in size and is used in the range hood 10000. It occupies a small space and can be arranged freely and flexibly in the air duct, thus facilitating the noise reduction design. Because the axial flow fan 1000 has the characteristic of straight airflow in and out, it is very easy to stack multiple stages without bringing high complexity to the structure. When used in the range hood 10000, a multi-stage blade assembly 2 is set to distribute the pressure rise, thereby achieving a significant noise reduction.

[0182] 2. The blades of the axial flow fan 1000 are usually distorted, which brings inconvenience to processing. The present invention improves the problem of high processing cost of the axial flow fan 1000 through the following aspects:

[0183] 2-1. The moving blades 21 and the stationary blades 22 of each stage are the same. The blade mold of the entire product only needs two sets of moving blades 21 and stationary blades 22. The aerodynamic performance of the axial flow fan 1000 can be changed by increasing or decreasing the number of stages of the blade assembly 2, so that the axial flow fan 1000 can be applied to products with different performance specifications, thereby reducing processing costs;

[0184] 2-2. Use softer materials such as plastic or aluminum alloy to make blades to reduce mold wear;

[0185] 2-3. The blade consistency is set to facilitate bidirectional rotation and demoulding of the blade;

[0186] 2-4. The shapes and sizes of the moving blades 21 at each level are the same, and the shapes and sizes of the stationary blades 22 at each level are the same, so as to reduce the manufacturing cost of the axial flow fan 1000 and facilitate increasing or decreasing the number of stages of the blade assembly 2 to adjust the performance of the axial flow fan 1000;

[0187] 2-5. A multi-stage blade assembly 2 is provided to achieve the target pressure rise, so the load of each stage of the blade assembly 2 is lighter and the degree of blade distortion is lower, which also reduces the processing difficulty.

[0188] 3. The aerodynamic noise of the first-stage blade assembly 2 of the axial flow fan 1000 in which the range hood 10000 is provided with a multi-stage blade assembly 2 will be directly transmitted to the inlet of the range hood 10000, while the aerodynamic noise of the blade assemblies 2 of the subsequent stages will be blocked by several rows of blades before being transmitted to the inlet of the range hood 10000, and the noise transmitted from the later stages will be blocked by more blades. Therefore, the earlier the stage, the greater the contribution to the noise felt by the user. Therefore, in the range hood of the present invention, both drs_i and dsr_j decrease as the number of stages increases, so that the pulsating noise generated at the upstream blade assembly 2 is weaker, thereby reducing the overall noise felt by the user. And by adjusting the size of drs_i / dsr_j to properly allocate the axial spacing, the noise of the axial flow fan 1000 is further reduced.

[0189] 4. By setting the blade shape of the rear suspension support plate 52, the residual velocity of the fluid flowing out of the blade assembly 2 is recovered, thereby improving the efficiency of the axial flow fan 1000; at the same time, by setting the thickness and slope of each part of the rear suspension support plate 52, the rear suspension support plate 52 can form a natural draft angle, which is convenient for casting and forming.

[0190] 5. By setting the front suspension support plate 51 and the rear suspension support plate 52 rotationally symmetrical, the front suspension support plate 51 allows the flow in front of the blade assembly 2 to generate pre-swirl, thereby improving the efficiency of the axial flow fan 1000; at the same time, the two suspension support plates 5 can be processed using the same process to reduce costs.

[0191] 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 a front portion, which extends axially in a first direction toward the outlet of the axial flow fan and forms a front edge of the rear suspension support plate. The thickness of the front portion gradually increases along the first direction. 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. In the front portion, at least the thickness of the windward side of the outer branch portion is less than the thickness of the leeward side. The slope of the contour tangent of the leeward side on the equal radius surface is negative. At least a part of the leeward surface is a deflection section. The absolute value of the slope of the contour tangent of the deflection section on the equal radius surface gradually decreases along the first direction.

2. The axial flow fan according to claim 1, characterized in that: The profile of the deflection flow section on the surface of constant radius is at least second-order differentiable.

3. The axial flow fan according to claim 1, characterized in that: The slope of the contour tangent of the windward surface of at least the outer branch part in the front part on the equal radius surface is positive or negative, and the absolute value of the slope remains unchanged or gradually decreases along the first direction.

4. The axial flow fan according to claim 1, characterized in that: The windward surface of at least the outer branch portion in the front portion has a straight line segment, and the absolute value of the profile slope of the straight line segment on the equal radius surface is less than or equal to 3°.

5. The axial flow fan according to claim 1, characterized in that: 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 rear portion gradually decreases along the first direction.

6. The axial flow fan according to claim 5, characterized in that: The axial length of the front portion is 0.25 to 0.5 times the axial length of the rear suspension support plate; And / or, the rear portion is arranged symmetrically with respect to the axial direction.

7. The axial flow fan according to claim 1 or 5, characterized in that: The axial flow fan further comprises a front suspension support plate and a front mounting member arranged in the housing, the front mounting member being arranged upstream of the rotating shaft and rotatably connected to the rotating shaft, the front suspension support plate being located upstream of the blade assembly and being fixed to the front mounting member and the housing respectively; The front suspension support plate and the rear suspension support plate are arranged in 180° rotational symmetry; and / or the front mounting member and the rear mounting member are arranged in 180° rotational symmetry.

8. The axial flow fan according to claim 7, characterized in that: The blade assembly comprises a moving blade mounted on the rotating shaft and a stationary blade mounted on the housing. 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 24°; Preferably, the outlet angle of the stationary blade is between 0° and 18°.

9. The axial flow fan according to claim 7, characterized in that: The windward surface of at least the outer branch portion of the front portion has a straight line segment, and the profile slope of the straight line segment on the equal radius surface is between 0° and 10°; And / or, the axial length of the front portion is 0.15 to 0.6 times the axial length of the rear suspension support plate; preferably 0.3 to 0.55 times.

10. 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.

11. The axial flow fan according to claim 10, characterized in that: The outer diameter of the rear mounting member gradually decreases along the first direction, and the maximum outer diameter 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.

12. The axial flow fan according to claim 11, characterized in that: The rear suspension support plate further includes a rear portion, the rear portion extends along the first direction and forms a trailing edge of the rear suspension support plate, the thickness of the rear portion gradually decreases along the first direction, the front portion and the rear portion are connected, and the rear suspension support plate is formed by casting; The windward side and the leeward side of the outer branch part in the rear part have contour tangent slopes of negative and positive, respectively, on a surface of equal radius; The slope of the contour tangent of the windward surface of the front part on the surface of equal radius is positive, and the boundary line between the front part and the rear part is used as the parting line, and the front part is obtained by axial drafting; preferably, the slopes of the contour tangent of the windward surface and the leeward surface of the inner branch part on the surface of equal radius are negative and positive respectively, and the inner branch part, the rear part in the outer branch part, and the rear mounting part are taken as the same casting module and obtained by axial drafting.

13. 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.

14. The axial flow fan according to claim 1, characterized in that: The axial flow fan comprises a plurality of stages of blade assemblies, which are arranged in sequence along a first direction. The blade assemblies comprise moving blades mounted on the rotating shaft and stationary blades mounted on the housing.

15. The axial flow fan according to claim 14, characterized in that: All moving blades have the same shape and size, and all stationary blades have the same shape and size; preferably, the stationary blades and moving blades are made of plastic or aluminum alloy; And / or, 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°; preferably, the outlet angle of the stationary blade is between 5° and 20°.

16. The axial flow fan according to claim 1, characterized in that: The minimum radius and the maximum radius of the blade flow channel are kept constant along the first direction; Preferably, the axial length range of the rotating shaft completely covers the axial length range of the blade assembly, and the blade flow channel is formed between the inner surface of the shell and the outer surface of the rotating shaft.

17. The axial flow fan according to claim 16, characterized in that: The number of stages of the blade assembly is K, and along the first direction: the blade assembly of the first stage, the blade assembly of the second stage, ..., the blade assembly of the Kth stage are arranged in sequence; The blade assembly comprises a moving blade mounted on the rotating shaft and a stationary blade mounted on the housing. In a single-stage blade assembly, the moving blade is arranged upstream of the stationary blade, and the average spacing between the trailing edge of the i-th stage moving blade and the leading edge of the i-th stage stationary blade along the axial direction is drs_i, i=1, 2, ..., K; the average spacing between the trailing edge of the j-th stage stationary blade and the leading edge of the j+1-th stage moving blade along the axial direction is dsr_j, j=1, 2, ..., K-1; As i increases, as j increases, drs_i and dsr_j change monotonically in the same direction; When K=2, drs_1≠drs_K; When K>2, drs_1≠drs_K and / or dsr_1≠dsr_K-1.

18. The axial flow fan according to claim 17, characterized in that: dsr_j≥drs_i, j=i; and / or, dsr_j>drs_(i+1), j=i; Preferably, the range of dsr_j / drs_i is between 1.1 and 1.5, and j=i.

19. A range hood, characterized in that: It comprises the axial flow fan as claimed in any one of claims 1 to 16, 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.

20. A range hood, characterized in that: It includes the axial flow fan as described in claim 17 or 18, the inlet of the axial flow fan is the inlet of the range hood or is connected to the inlet of the range hood, the outlet of the axial flow fan is the outlet of the range hood or is connected to the outlet of the range hood, drs_1≥drs_2≥……≥drs_K, dsr_1≥dsr_2≥……≥dsr_(K-1).

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