Axial flow fan and extractor hood comprising same

Abstract

This invention relates to the field of axial flow fans, and discloses an axial flow fan and a range hood including the same. The axial flow fan includes a housing, a rotating shaft, a blade assembly, a rear mounting component, and a rear suspension support plate. The blade assembly is disposed in a blade flow channel formed between the rotating shaft and the housing. The downstream end of the rotating shaft is rotatably connected to the rear mounting component. The rear suspension support plate is fixedly connected to the rear mounting component and the housing. The thickness of the front portion of the rear suspension support plate gradually increases along a first direction. At least the outer support portion of the front portion is biased towards the leeward side, and the slope of the tangent of the leeward side on the plane of equal radius is negative. It also has a deflection section. The absolute value of the slope of the tangent of the deflection section on the plane of equal radius gradually decreases along the first direction, so as to recover the residual velocity of the incoming flow at the blade assembly and improve the efficiency of the axial flow fan.

Description

Technical Field

[0001] This invention relates to the field of axial flow fans, and more particularly to an axial flow fan with residual velocity recovery. Background Technology

[0002] In axial flow fans, the fluid flowing out from the stationary blades often has a velocity component perpendicular to the axial direction. The kinetic energy carried by this velocity component is dissipated 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 low efficiency of axial flow fans 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-mentioned technical problems through the following technical solution:

[0005] An axial flow fan, comprising:

[0006] case;

[0007] The rotating shaft is disposed within the housing;

[0008] At least one blade assembly is disposed within the blade flow channel;

[0009] The axial flow fan also includes a rear suspension support plate and a rear mounting component disposed within the housing. The rear mounting component is disposed downstream of the rotating shaft and 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 component and the housing, respectively.

[0010] The rear suspension plate has a front portion that extends axially toward the outlet of the axial flow fan in a first direction and forms the leading edge of the rear suspension plate. The thickness of the front portion gradually increases along the first direction. The rear suspension plate has an outer support portion with a radius greater than or equal to the minimum radius of the downstream end of the blade flow channel. The thickness of at least the windward side of the outer support portion in the front portion is less than the thickness on the leeward side. The slope of the tangent of the leeward side on the plane of equal radius is negative. At least a portion of the leeward side is a deflection section. The absolute value of the slope of the tangent of the deflection section on the plane of equal radius gradually decreases along the first direction.

[0011] In this design, the fluid flows through the blade assembly and then towards the rear suspension plate. The thickness of the front portion of the rear suspension plate gradually increases along the first direction to facilitate a smooth flow split at the leading edge of the rear suspension plate. The radius of the outer support portion of the front part of the rear suspension plate is greater than or equal to the minimum radius of the downstream end of the blade flow channel. This portion guides 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 outer support portion of the front part of the rear suspension plate to be less than the thickness of the leeward side, this part is biased towards the leeward side as a whole. After the fluid passes through the front part of the rear suspension plate, the fluid can be guided to reduce the degree of relative axial deflection of the fluid.

[0013] On the other hand, the slope of the leeward profile tangent of the outer support of the front part of the rear suspension plate is negative, and a deflection section is set on the leeward side of this part. The absolute value of the slope of the deflection section gradually decreases, so that the profile tangent of the deflection section gradually approaches the axis. When the fluid passes through the front part of the rear suspension plate, the flow direction can be gradually deflected to approach the axis, further reducing the degree of deflection of the fluid relative to the axis.

[0014] By designing in these two aspects to reduce the deflection of the fluid after it flows out of the blade assembly, the non-axial velocity component of the fluid flowing out of the blade assembly can be recovered, which is referred to as residual velocity recovery, thereby reducing flow losses and noise.

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

[0016] In this design, the surface of the deflection section is streamlined and changes gradually, which facilitates processing and makes the fluid flow smooth.

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

[0018] In this design, when the slope is positive, it facilitates the axial demolding of the front part when the rear suspension support plate is cast, making processing convenient.

[0019] When the slope is negative, the front portion of the rear suspension plate is offset more towards the leeward side, which can further reduce the relative axial deflection of the fluid. Furthermore, when a front suspension plate is installed, and the front and rear suspension plates are symmetrically arranged at 180° rotation, the front portion of the rear suspension plate is equivalent to the rear portion of the front suspension plate. This arrangement can increase the pre-swirl of the flow in front of the blade assembly, thereby improving the pressure rise efficiency of the axial flow fan.

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

[0021] In this design, straight segments are used for ease of processing. Furthermore, setting the absolute value of the slope corresponding to the straight segments to be less than or equal to 3° ensures that the thickness of the outer support in the front part is large enough, thereby ensuring sufficient strength, allowing for casting and demolding, and providing sufficient thickness space for setting the deflection section on the leeward side.

[0022] Preferably, the rear suspension plate further includes a rear portion, which extends along a first direction and forms the tail edge of the rear suspension plate, and the thickness of the rear portion gradually decreases along the first direction.

[0023] In this design, the thickness at the trailing edge of the rear suspension plate is sufficiently small, which helps to reduce the wake of the fluid after it flows over the rear suspension plate, thereby reducing flow loss and noise.

[0024] When the front and rear suspension plates are set in a 180° rotational symmetrical configuration, the rear part of the rear suspension plate is equivalent to the front part of the front suspension plate. This configuration allows the thickness at the front edge of the front suspension plate to be sufficiently small, and the thickness change of the front part of the front suspension plate to be gradual, which facilitates the diversion of fluid in the front part of the front suspension plate.

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

[0026] In this design, the front section is long enough to effectively deflect the fluid, while the front section is short enough to provide sufficient length for the rear section. Even if the fluid separates from the surface of the rear suspension plate after flowing from the front section to the rear section, the rear section has enough length for the fluid to re-attach to the surface of the rear suspension plate, thus suppressing the separation.

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

[0028] In this design, the process is convenient, and the fluid flows out axially.

[0029] Preferably, the axial flow fan further includes a front suspension support plate and a front mounting component disposed within the housing. The front mounting component is disposed upstream of the rotating shaft and rotatably connected to the rotating shaft. The front suspension support plate is located upstream of the blade assembly and is fixed to the front mounting component and the housing, respectively.

[0030] The front suspension plate and the rear suspension plate are arranged in a 180° rotational symmetry configuration; and / or, the front mounting component and the rear mounting component are arranged in a 180° rotational symmetry configuration.

[0031] In this design, the front and rear suspension plates are arranged in a 180° rotational symmetry. On the one hand, this allows the front part of the rear suspension plate to correspond to the rear part of the front suspension plate, and the rear part of the front suspension plate can deflect the incoming flow in front of the blade assembly, causing the fluid to generate negative pre-swirl, thereby improving the efficiency of the axial flow fan. On the other hand, it facilitates the use of the same process to manufacture the front and rear suspension plates, reducing processing costs.

[0032] The front and rear mounting components are arranged in a 180° rotational symmetry. On the one hand, this facilitates the use of the same manufacturing process for both the front and rear mounting components, reducing processing costs. On the other hand, it allows the front suspension bracket and the front mounting component to be integrally formed and manufactured using the same process as the rear suspension bracket and the rear mounting component.

[0033] Preferably, the blade assembly includes 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 located upstream of the stationary blade, the absolute value of the exit angle of the moving blade is greater than the absolute value of the exit angle of the stationary blade, and the exit angle of the stationary blade is between 0° and 24°.

[0034] In this design, the fluid is deflected by the front suspension plate, resulting in a sufficiently large pre-swirl of the inflow in front of the blade assembly, thereby improving the efficiency of the axial flow fan. At the same time, the rear suspension plate can effectively recover the residual velocity of the fluid flowing out of the blade assembly, thus effectively reducing flow losses and noise.

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

[0036] Preferably, at least the outer support portion of the front portion has a straight section on its windward side, and the slope of the straight section on the surface of equal radius is between 0° and 10°.

[0037] In this design, the rear suspension plate is configured to have sufficient thickness to accommodate the deflection section. This allows the absolute value of the slope of the tangent line on the equal radius surface of the deflection section to gradually decrease significantly along the first direction, thereby improving the deflection effect of the deflection section. For the rear suspension plate, this ensures a sufficiently good recovery effect of the residual velocity of the fluid flowing out of the blade assembly, reducing flow losses and noise. For the front suspension plate, this ensures that the fluid generates a sufficiently large degree of pre-swirl before flowing towards the blade assembly, thus 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 plate.

[0039] In this design, the front portion of the rear suspension plate is configured in two ways. First, it ensures that the front portion is long enough to effectively deflect the fluid and recover residual velocity. Second, it ensures that the rear portion of the front suspension plate provides sufficient pre-swirl for the fluid. Third, the front portion of the rear suspension plate is short enough to allow sufficient length for the rear portion. When the fluid separates from the surface of the rear suspension plate after flowing from the front portion to the rear portion, the rear portion has enough length to allow the fluid to re-adhere to the surface of the rear suspension plate, thus suppressing separation. Fourth, the front portion of the front suspension plate is long enough to facilitate a smooth flow of fluid from the front portion.

[0040] Preferably, the axial length of the front portion is 0.3 to 0.55 times the axial length of the rear suspension plate.

[0041] Preferably, the rear suspension plate further includes an inner support portion with a radius smaller than the minimum radius of the downstream end of the blade flow channel, and the rear mounting component is at least mounted on the inner support portion.

[0042] In this solution, by setting an internal support section to install the rear mounting parts, the axial space occupied by the rotating shaft can be reduced, which makes it easier to reduce the length of the rotating shaft. On the one hand, it can reduce the amount of material used and reduce the overall weight and cost of the axial flow fan; on the other hand, it can make the axial dimensions of the axial flow fan compact.

[0043] Preferably, the outer diameter of the rear mounting component 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.

[0044] In this design, the surface shape of the rear mounting component 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 component has the same diameter as the blade flow channel, which allows the fluid to flow smoothly from the blade assembly to the rear mounting component and then smoothly over the rear mounting component, reducing the loss of fluid flow dynamics.

[0045] Preferably, the radius at the leading edge of the root of the rear suspension plate is equal to the minimum radius at the downstream end of the blade channel.

[0046] In this scheme, the arrangement can improve the convenience of processing the rear suspension support plate, especially when the rear suspension support plate and the rear mounting component are cast together, it is convenient to extract the outer support part of the front part of the rear suspension support plate along the axial direction.

[0047] Preferably, the rear suspension plate further includes a rear portion, which extends along a first direction and forms the tail edge of the rear suspension plate. The thickness of the rear portion gradually decreases along the first direction. The front portion and the rear portion are connected. The rear suspension plate is formed by casting.

[0048] The slopes of the tangent lines on the windward and leeward sides of the outer support portion in the rear section are negative and positive, respectively, on the plane of equal radius.

[0049] The slope of the tangent line of the windward surface of the front part on the plane of equal radius is positive. The front part is obtained by drafting along the axial direction using the dividing line between the front part and the rear part as the parting line.

[0050] Preferably, the slopes of the tangent lines of the windward and leeward sides of the inner support portion on the plane of equal radius are negative and positive, respectively, and the rear portion of the inner support portion, the rear mounting component of the outer support portion, and the rear installation component are obtained by axial demolding as the same casting module.

[0051] 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.

[0052] In this design, the rear suspension plates are arranged so densely that the residual velocity recovery effect is good enough.

[0053] When the front and rear suspension plates are set in a 180° rotational symmetrical configuration, it can be ensured that the front suspension plate can generate a sufficiently good pre-swirl effect on the fluid.

[0054] Preferably, the average consistency of the rear suspension plate is greater than or equal to 1.

[0055] Preferably, the axial flow fan includes multiple stages of the blade assembly, which are arranged sequentially along a first direction. Each blade assembly includes a moving blade mounted on the rotating shaft and a stationary blade mounted on the housing.

[0056] In this design, by using multiple stages to achieve the pressure rise and flow rate of the single-stage blade assembly, the sound power can be reduced to 1 / K of the original. This allows the axial fan to maintain a low noise level while ensuring sufficient aerodynamic performance. Furthermore, the multi-stage blade assembly design, with each row of blades shielding noise transmission, provides reflection and absorption, further reducing noise.

[0057] Ideally, all moving blades should have the same shape and size, and all stationary blades should have the same shape and size.

[0058] In this solution, the moving blades and stationary blades are set to have the same shape and size. Regardless of the number of blade assembly stages, only two sets of blade molds are needed: one for the moving blades and one for the stationary blades. The aerodynamic performance of the axial flow fan can be changed by increasing or decreasing the number of blade assembly stages. It has good versatility and low processing cost.

[0059] Preferably, the stationary blade and the moving blade are made of plastic or aluminum alloy.

[0060] In this design, the relatively soft plastic or aluminum alloy materials can reduce wear on the mold when casting the blades; the relatively light plastic or aluminum alloy materials can reduce the weight of the axial flow fan when used in the axial flow fan.

[0061] Preferably, in the single-stage blade assembly, the moving blade is disposed upstream of the stationary blade, the absolute value of the exit angle of the moving blade is greater than the absolute value of the exit angle of the stationary blade, and the exit angle of the stationary blade is between 0° and 40°.

[0062] In this design, the outlet angles of the moving and stationary blades are set so that the fluid, after passing through the stationary blades, is deflected relative to the axial direction before flowing to the next stage moving blades, thus improving the pressure rise efficiency of the axial flow fan. Simultaneously, the deflection section of the rear-mounted support plate deflects the fluid exiting the last stage stationary blade, making the fluid flow direction closer to the axial direction, thereby reducing flow losses.

[0063] When the front and rear suspension plates are set in a 180° rotational symmetrical configuration, the deflection section in the rear suspension plate corresponds to the windward side of the rear part of the front suspension plate. This deflects the fluid, causing it to generate a negative pre-swirl angle after passing the front suspension plate before flowing towards the first-stage moving blade. On the one hand, this can improve the efficiency of the axial flow fan. On the other hand, when the blade assemblies of each stage are repeatedly arranged, the front suspension plate deflects the incoming flow in front of the first-stage moving blade, making the incoming flow conditions in front of each stage of the moving blade similar. This facilitates a relatively consistent fluid flow at each stage of the blade assembly, thereby fully utilizing the performance of the repeated blade assemblies in the axial flow fan.

[0064] Preferably, in the single-stage blade assembly, the moving blade is located upstream of the stationary blade, the absolute value of the exit angle of the moving blade is greater than the absolute value of the exit angle of the stationary blade, and the exit angle of the stationary blade is between 5° and 20°.

[0065] Preferably, the minimum and maximum radii of the blade flow channel remain constant along the first direction;

[0066] Preferably, the axial length of the rotating shaft completely covers the axial length of the blade assembly, and the blade flow channel is formed between the inner surface of the housing and the outer surface of the rotating shaft.

[0067] In this design, the following advantages are achieved: Firstly, it facilitates manufacturing. Secondly, when the blade assemblies at each stage are repeatedly arranged, keeping the minimum and maximum radii of the blade flow channels constant ensures flow channel stability. This facilitates similar inflow conditions in front of each stage of moving or stationary blades, and ensures that the fluid flow at each stage of the blade assembly is basically consistent, thereby fully utilizing the performance of the repeated blade assemblies in the axial flow fan.

[0068] 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 sequentially;

[0069] The blade assembly includes 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 located upstream of the stationary blade. The average distance along the axial direction between the trailing edge of the i-th stage moving blade and the leading edge of the i-th stage stationary blade is drs_i, i = 1, 2, ..., K; the average distance along the axial direction between the trailing edge of the j-th stage stationary blade and the leading edge of the (j+1)-th stage moving blade is dsr_j, j = 1, 2, ..., K-1.

[0070] As i increases, as j increases, drs_i and dsr_j change monotonically in the same direction;

[0071] When K = 2, drs_1 ≠ drs_K;

[0072] When K > 2, drs_1 ≠ drs_K and / or dsr_1 ≠ dsr_K-1.

[0073] In this design, a larger drs_i in the axial flow fan results in more uniform mixing of the fluid as it flows from the trailing edge of the moving blade to the trailing edge of the stationary blade, thus improving blade frequency noise and reducing fluid flow noise. Similarly, a larger dsr_j results in more uniform mixing of the fluid as it flows from the trailing edge of the preceding stationary blade to the leading edge of the following moving blade, also improving blade frequency noise and reducing fluid flow noise.

[0074] As i and j increase, drs_i and dsr_j change monotonically in the same direction. Furthermore, when K = 2, drs_1 ≠ drs_K, and when K > 2, drs_1 ≠ drs_K and / or dsr_1 ≠ dsr_K-1. This ensures that drs_i and dsr_j are larger the closer they are to the inlet or outlet of the axial flow fan.

[0075] Firstly, when the values ​​of drs_i and dsr_j are larger closer to the inlet of the axial flow fan, the fluid is mixed more evenly at the blades closer to the inlet, and the noise generated by the fluid flow itself is smaller. Moreover, the noise generated by the fluid flow at the downstream blades, which is relatively greater than that at the upstream blades, is gradually weakened by the shielding of multiple rows of blades, thereby reducing the noise transmitted upstream. Therefore, the noise in the upstream part of the axial flow fan, especially at the inlet, can be reduced.

[0076] Secondly, similar to the first point, when the values ​​of drs_i and dsr_j are larger closer to the outlet of the axial flow fan, the fluid is mixed more evenly at the blades closer to the outlet, and the noise generated by the fluid flow itself is smaller. Moreover, the noise generated by the fluid flow at the upstream blades, which is relatively greater than that at the downstream blades, is gradually weakened by the shielding of multiple rows of blades, thereby reducing the noise transmitted downstream. Therefore, the noise in the downstream part of the axial flow fan, especially at the outlet, can be reduced.

[0077] Thirdly, it is possible to reduce the noise at the inlet or outlet of the axial flow fan while avoiding an increase in the axial dimension of the axial flow fan; or, while avoiding an increase in the noise at the inlet or outlet of the axial flow fan, it is possible to reduce the axial dimension of the axial flow fan.

[0078] Preferably, dsr_j≥drs_i, j=i; and / or, dsr_j>drs_(i+1), j=i;

[0079] In this scheme, dsr_j > drs_i and / or dsr_j > drs_(i+1) is 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 stationary blades to the leading edge of the rear moving blades, thereby reducing the overall noise of the axial flow fan.

[0080] Ideally, dsr_j / drs_i should be in the range of 1.1 to 1.5, where j = i.

[0081] A range hood includes 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.

[0082] A range hood includes 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, drs_1≥drs_2≥……≥drs_K, dsr_1≥dsr_2≥……≥dsr_(K-1).

[0083] In this solution, an 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.

[0084] The positive and progressive effects of this invention are as follows:

[0085] After flowing through the blade assembly, the fluid flows towards the rear suspension plate. The thickness of the front portion of the rear suspension plate gradually increases along the first direction to facilitate a smooth flow split at the leading edge of the rear suspension plate. The radius of the outer support portion of the front part of the rear suspension plate is greater than or equal to the minimum radius of the downstream end of the blade flow channel. This portion guides the fluid flowing out of the blade assembly. When the flow direction of the fluid flowing out of the blade assembly is negative:

[0086] On the one hand, by setting the thickness of the outer support portion of the front part of the rear suspension plate to be less than the thickness of the leeward side, this part is biased towards the leeward side as a whole. After the fluid passes through the front part of the rear suspension plate, the fluid can be guided to reduce the degree of relative axial deflection of the fluid.

[0087] On the other hand, the slope of the leeward profile tangent of the outer support of the front part of the rear suspension plate is negative, and a deflection section is set on the leeward side of this part. The absolute value of the slope of the deflection section gradually decreases, so that the profile tangent of the deflection section gradually approaches the axis. When the fluid passes through the front part of the rear suspension plate, the flow direction can be gradually deflected to approach the axis, further reducing the degree of deflection of the fluid relative to the axis.

[0088] By designing in these two aspects to reduce the deflection of the fluid after it flows out of the blade assembly, the non-axial velocity component of the fluid flowing out of the blade assembly can be recovered, which is referred to as residual velocity recovery, thereby reducing flow losses and noise.

[0089] The front and rear suspension plates are arranged in a 180° rotational symmetry. On the one hand, this allows the front part of the rear suspension plate to correspond to the rear part of the front suspension plate, and the rear part of the front suspension plate can deflect the incoming flow in front of the blade assembly, causing the fluid to generate negative pre-swirl, thereby improving the efficiency of the axial flow fan. On the other hand, it makes it easier for the front and rear suspension plates to be manufactured using the same process, reducing processing costs. Attached Figure Description

[0090] Figure 1 This is a schematic diagram of the range hood in Example 1;

[0091] Figure 2 This is a schematic diagram of the external structure of the axial flow fan in Example 1;

[0092] Figure 3 This is a schematic diagram of the internal structure of the axial flow fan in Example 1;

[0093] Figure 4 This is a meridional view of the axial flow fan in Example 1;

[0094] Figure 5 This is a schematic diagram of the axial flow fan with equal radius in Example 1;

[0095] Figure 6This is a schematic diagram of the rear mounting component and rear suspension bracket in Example 1;

[0096] Figure 7 This is a schematic diagram of the front mounting component and front suspension support plate in Example 1;

[0097] Figure 8 This is a schematic diagram of the rear suspension support plate in Example 1;

[0098] Figure 9 This is a meridional view of the rear suspension plate of the axial flow fan in Example 1;

[0099] Figure 10 This is a meridional view of the front suspension plate of the axial flow fan in Example 1;

[0100] Figure 11 This is a schematic diagram of the outer support portion of the rear suspension plate in Example 1 on a plane with equal radius, and a schematic diagram of the corresponding portion in the front suspension plate;

[0101] Figure 12 This is a schematic diagram of the inner support portion of the rear suspension plate in Example 2 on a surface of equal radius;

[0102] Figure 13 This is a meridional view of the rear suspension plate of the axial flow fan in Example 2;

[0103] Figure 14 This is a draft diagram of the rear suspension support plate on a plane with equal radius in Example 2;

[0104] Figure 15 This is a schematic diagram of the outer support portion of the rear suspension plate in Example 3 on a plane with equal radius, and a schematic diagram of the corresponding portion in the front suspension plate;

[0105] Figure 16 This is a draft diagram of the rear suspension support plate on a surface of equal radius in Example 3;

[0106] Figure 17 This is a meridional view of the rear suspension plate of the axial flow fan in another embodiment.

[0107] Explanation of reference numerals in the attached figures:

[0108] 1000 axial flow fan;

[0109] Housing 1, front housing 11, rear housing 12;

[0110] Blade assembly 2;

[0111] 21 moving leaves, 211 primary moving leaves, 212 secondary moving leaves, 213 tertiary moving leaves;

[0112] Static Leaf 22, Level 1 Static Leaf 221, Level 2 Static Leaf 222, Level 3 Static Leaf 223;

[0113] Shaft 3;

[0114] Mounting component 4, front mounting component 41, rear mounting component 42;

[0115] Suspension plate 5;

[0116] Front suspension support plate 51, first part 511, second part 512, third part 513;

[0117] Rear suspension support plate 52, fourth part 521, fifth part 522, sixth part 523, deflection section 524, straight section 525;

[0118] External branch 531, internal branch 532;

[0119] Front-mounted section 541, rear-mounted section 542;

[0120] Windward side 551, leeward side 552;

[0121] First pouring section 561, second pouring section 562;

[0122] Blade channel 6;

[0123] Smoke hood 2000, outer casing 3000;

[0124] Range hood 10000. Detailed Implementation

[0125] The present invention will be further illustrated by way of embodiments below, but the present invention is not limited to the scope of the embodiments described herein.

[0126] Example 1

[0127] This embodiment provides a range hood. Figures 1-11 This is a schematic diagram of the structure of this embodiment.

[0128] like Figure 1 The range hood 10000 includes an axial flow fan 1000, a smoke collection hood 2000, and a housing 3000. The bottom of the smoke collection hood 2000 has an opening to serve as the inlet of the range hood 10000. The housing 3000 and the smoke collection hood 2000 are fixed together. The axial flow fan 1000 is installed inside the housing 3000. The inlet of the axial flow fan 1000 is connected to the inlet of the range hood 10000. The outlet of the axial flow fan 1000 forms the outlet of the range hood 10000.

[0129] In this embodiment, the length, width, and height directions of the range hood 10000 are X, Y, and Z, respectively. These three directions are perpendicular to each other, with the Z direction parallel to the vertical direction. In the accompanying drawings of this invention, the Z-axis coincides with the axis of the axial flow fan 1000. The direction of the Z-axis is from the inlet to the outlet of the axial flow fan 1000, which also corresponds to the direction in which the fluid flows from upstream to downstream in the axial flow fan 1000. For ease of description below, the direction of the Z-axis will be referred to as the "first direction".

[0130] In a preferred embodiment, the outlet inner diameter of the axial flow fan 1000 is between 160mm and 220mm, making it close to the inner diameter of commonly used general-purpose flue pipes, thus facilitating the connection between the outlet of the axial flow fan 1000 and the general-purpose flue pipe. Furthermore, setting the outlet inner diameter of the axial flow fan 1000 between 175mm and 185mm makes it close to the inner diameter of most general-purpose flue pipes, further improving the convenience of connecting the axial flow fan 1000 and the flue pipe.

[0131] In other embodiments, the shape and installation direction of the range hood 10000 can be adjusted according to usage requirements. The inlet of the axial fan 1000 can be used as the inlet of the range hood 10000, for example, when the smoke collection hood 2000 is not installed; or, the inlet of the axial fan 1000 and the inlet of the range hood 10000 can be connected. The outlet of the axial fan 1000 can be used as the outlet of the range hood 10000; or, the outlet of the axial fan 1000 and the outlet of the range hood 10000 can be connected by a pipe.

[0132] like Figures 2-5 The axial flow fan 1000 includes a housing 1, and a rotating shaft 3, a blade assembly 2, two types of suspension plates 5 (front suspension plate 51 and rear suspension plate 52), and two types of mounting components 4 (front mounting component 41 and rear mounting component 42) disposed within the housing 1.

[0133] The blade flow channel 6 is a well-known concept, referring to the flow channel range of the blade assembly 2 within the casing 1 of the axial flow fan 1000 along the Z-direction from the leading edge to the trailing edge. Figure 4 The Z_YPLD diagram illustrates the range of the blade flow channel 6 along the Z-direction. For example... Figure 4 A blade flow channel 6 is formed between the inner surface of the housing 1 and the surfaces of other components in the housing 1 except for the blade assembly 2. In this embodiment, the blade flow channel 6 is specifically formed by the inner surface of the housing 1 and the outer surface of the rotating shaft 3; the blade assembly 2 is disposed in the blade flow channel 6.

[0134] The front suspension support plate 51 is located upstream of the blade assembly 2 and fixed to the housing 1; the front mounting piece 41 is located upstream of the rotating shaft 3 and rotatably connected to the upstream end of the rotating shaft 3, and fixed to the front suspension support plate 51; the rear suspension support plate 52 is located downstream of the blade assembly 2 and fixed to the housing 1; the rear mounting piece 42 is located downstream of the rotating shaft 3 and rotatably connected to the downstream end of the rotating shaft 3, and fixed to the rear suspension support plate 52. The rotatable connection method includes, but is not limited to, connection via bearings. Figure 6 , Figure 7 A perspective view of the suspension support plate 5 and the corresponding mounting component 4 is shown. The mounting component 4 and the suspension support plate 5 are set 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 ease of manufacturing the axial flow fan 1000.

[0135] like Figures 3-5 The blade assembly has 3 stages (K=3). A single-stage blade assembly 2 includes two types of blades: a moving blade 21 and a stationary blade 22. Along the Z-axis, 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 sequentially at intervals. The stationary blade 22 is mounted on the housing 1, and the moving blade 21 is mounted on the rotating shaft 3. (The last sentence appears to be incomplete and possibly refers to a different blade assembly.) Figure 2 The housing 1 of the axial flow fan 1000 includes a front housing 11 and a rear housing 12, and the flanges of the front housing 11 and the rear housing 12 are fixedly connected.

[0136] In this embodiment, by using a K-class blade assembly 2 to achieve the pressure rise and flow rate, the sound power can be reduced to 1 / K of the original. This allows the axial fan 1000 to maintain a low noise level while ensuring sufficient aerodynamic performance. Furthermore, the K-class blade assembly 2 design ensures that each row of blades blocks noise transmission, providing reflection and absorption, further reducing noise. Applying the K-class axial fan 1000 to the range hood 10000 results in good aerodynamic performance and low noise.

[0137] Consistency is a well-known concept. Blade consistency can be understood as the chord length of the blade divided by the distance between two adjacent blades in a single row. 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 less than or equal to 1.8, ensuring that the blades in a single row are arranged sparsely enough to facilitate demolding during casting. Setting the maximum consistency of a single row of blades to less than or equal to 1.4 yields even better results.

[0138] In a preferred embodiment, such as this embodiment, the moving blades 21 and stationary blades 22 are all of the same shape and size, forming repeating blade assemblies 2. Regardless of the number of stages in the blade assembly 2, only two sets of molds are needed for the 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 in the blade assembly 2, resulting in good versatility and low processing costs. Furthermore, the stationary blades 22 and moving blades 21 can be made of softer materials such as plastic or aluminum alloy, which can reduce wear on the molds during the casting process. Lighter materials such as plastic or aluminum alloy can reduce the weight of the axial flow fan 1000.

[0139] In other embodiments, the axial fan 1000 may be provided with two, three or more stages of blade assembly 2. By increasing the number of stages of blade assembly 2, the aerodynamic performance of the range hood 10000 can be improved, and the radial dimension of the axial fan 1000 can be made smaller, so as to reduce the space occupied by the axial fan 1000 in the X and Y directions in the kitchen.

[0140] In a preferred embodiment, such as 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 and maximum radii of the blade flow channel 6 are kept constant, forming a stable blade flow channel 6. This facilitates the approach of the incoming flow conditions in front of each stage of moving blade 21 or each stage of stationary blade 22, and makes the fluid flow conditions at each stage of blade assembly 2 basically consistent, so as to give full play to the performance of the repeated blade assembly 2 in the axial flow fan 1000.

[0141] In a preferred embodiment, the hub ratio of the blade flow channel 6 is r1 / r2, ranging from 0.4 to 0.8, which makes the hub ratio large enough, thereby making the blade height small enough, so that the blade tip and root curvature can be set small, the fluid flow is smooth, and the noise is low; and the hub ratio is small enough, thereby making the blade height large enough, so that the channel through which the fluid flows through the blade is large enough, and the flow rate is large enough.

[0142] like Figure 5 The rotation direction of shaft 3 is W. When the fluid flow 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-swirl" when flowing towards the blade assembly, and "residual velocity" when flowing out of the blade assembly. When this component is in the same direction as W, it is a negative residual velocity or negative pre-swirl.

[0143] In a preferred embodiment, such as Figure 5The 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°. This causes the fluid to deflect relative to the axial direction after passing through the stationary blade 22 before flowing to the next stage moving blade 21, which facilitates the generation of negative pre-swirl and can improve the pressure rise efficiency of the axial flow fan 1000. The fluid flowing out from the last stage stationary blade 22 has a negative residual velocity. In this invention, a rear suspension support plate 52 is set to recover the residual velocity of the fluid, thereby reducing flow losses and ensuring that the axial flow fan has a sufficiently high efficiency. 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 β4 is positive, and the trailing edge of the stationary blade 22 points in the same direction as the rotation of the shaft 3.

[0144] In a preferred embodiment, such as this embodiment, the front suspension support plate 51 and the rear suspension support plate 52 are arranged with 180° rotational symmetry and have the same shape and size. This means that the rear suspension support plate 52, after being rotated 180°, can be used as the front suspension support plate 51 and installed on the front mounting member 41. The front mounting member 41 and the rear mounting member 42 are also arranged with 180° rotational symmetry. This arrangement allows both types of suspension support plates 5 and both types of mounting members 4 to be manufactured using the same process, reducing manufacturing costs.

[0145] like Figure 8 , Figure 9 The rear suspension plate 52 has an outer support portion 531 with a radius greater than the minimum radius r1 at the downstream end of the blade flow channel 6, and an inner support portion 532 with a radius less than r1. Figure 8 The plane LR, drawn with dashed lines, roughly illustrates the boundary between the outer support portion 531 and the inner support portion 532. The rear mounting component 42 is at least fixed to the inner support portion 532. By setting the inner support portion 532 to mount the rear mounting component 42, the axial space occupied by the rear suspension plate 52 on the rotating shaft 3 can be reduced, facilitating a reduction in the length of the rotating shaft 3. On the one hand, this reduces material usage, lowering the overall weight and cost of the axial flow fan 1000; on the other hand, it allows for a more compact axial dimension of the axial flow fan 1000. The radius of the outer support portion 531 in the rear suspension plate 52 is greater than or equal to the minimum radius of the downstream end of the blade assembly 2, providing a strong guiding effect on the fluid flowing out from the blade assembly 2. The rear suspension plate 52 can be configured with only the outer support portion 531. For example... Figure 17 In the corresponding embodiment, the rear suspension plate 52 does not have an inner support portion 532.

[0146] like Figure 8 The rear suspension plate 52, along the Z-direction, has a front portion 541 with gradually increasing thickness T and a rear portion 542 with gradually decreasing thickness. The thickness T is indicated in [reference needed]. Figure 11 The leading edge of the rear suspension plate 52 is formed in the front portion 541, and the trailing edge of the rear suspension plate 52 is formed in the rear portion 542. Figure 8 The plane indicated by LZ represents the approximate boundary between the front portion 541 and the rear portion 542. After flowing through the blade assembly 2, the fluid flows towards the rear suspension plate 52. The thickness of the front portion 541 of the rear suspension plate 52 gradually increases along the Z-direction to facilitate smooth fluid diversion at the leading edge of the rear suspension plate 52. The thickness of the rear portion 542 of the rear suspension plate 52 gradually decreases along the Z-direction to reduce the wake of the fluid after passing through the rear suspension plate 52, thereby reducing flow losses and noise. Furthermore, the front suspension plate 51 and the rear suspension plate 52 are 180° rotationally symmetrical. The rear portion 542 of the rear suspension plate 52 is equivalent to the front portion of the front suspension plate 51. The gradually decreasing thickness of the rear portion 542 along the Z-direction ensures that the thickness at the leading edge of the front suspension plate 51 is sufficiently small, and the thickness change in the front portion of the front suspension plate 51 is gradual, facilitating fluid diversion in the front portion of the front suspension plate 51.

[0147] Table 1. Division of 5 parts of the suspension support plate

[0148] Rear suspension support plate 52 middle section Abbreviation Corresponding part in front suspension support plate 51 The front part of the outer branch 531 is 541. Part 4 521 Part Two 512 External support section 531, rear section 542 Part 5 522 Part 1, 511 Internal branch 532 Part 6 523 Part Three 513

[0149] For ease of understanding, the various parts of the front suspension plate 51 and the rear suspension plate 52 are divided in this invention, as shown in Table 1. Figure 9 The dashed lines in the middle indicate the approximate boundaries between Part 4 (521), Part 5 (522), and Part 6 (523); Figure 10 The dashed lines in the middle indicate the approximate boundaries between the first part 511, the second part 512, and the third part 513.

[0150] Figure 11 The shape of the outer support portion 531 in the rear suspension support plate 52 on the equal radius surface is shown. The equal radius surface is a virtual cylindrical surface with the axis of the axial flow fan 1000 as the axis. The axial flow fan 1000 has an infinite number of equal radius surfaces.

[0151] like Figure 8 , Figure 9 , Figure 11 The thickness T1 of the front portion 541 of the rear suspension plate 52 on the windward side 551 is less than the thickness T2 on the leeward side 552, causing the front portion 541 to be biased towards the leeward side 552. With this configuration, when the fluid from the blade assembly 2 has a negative residual velocity, it flows through the front portion 541. The front portion 541 can guide the fluid to reduce the relative axial deflection of the fluid, thereby recovering the residual velocity, reducing flow losses, and improving the efficiency of the axial fan 1000. Furthermore, due to the improved efficiency of the axial fan 1000, the rotational speed of the axial fan 1000 can be reduced to achieve the same output, thus reducing noise. Figure 11The dashed line L-T1, which passes through the leading edge point P1-1 of the front part 541 and is parallel to the Z direction, can be understood as the boundary between the thickness of the windward side 551 and the leeward side 552 of the rear suspension plate 52.

[0152] like Figure 11 In the front section 541, the slope of the tangent line on the equiradial surface of the leeward side 552 is negative, and it flows in the same direction as the incoming flow with negative residual velocity. At least part of the leeward side 552 is a deflection section 524. The absolute value of the slope of the tangent line on the equiradial surface of the deflection section 524 gradually decreases along the Z-direction, so that the tangent line of the deflection section 524 gradually approaches the axial direction. As the fluid passes through the front section 541, its flow direction can gradually deflect 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 this invention, within the equiradial surface, the contour tangent line uses the opposite directions of the Z and W directions as two-dimensional coordinate axes; the slope of the contour tangent line is positive, that is, the angle between the tangent line and the Z-direction is positive. Figure 11 The diagram shows the contour tangent line L1 of point P2 on the leeward side 552 of the front part 541 on the surface of equal radius, with the slope of L1 being negative.

[0153] like Figure 11 The front part 541 of the rear suspension plate 52 corresponds to the rear part of the front suspension plate 51. The front part 541 can recover the negative residual velocity of the fluid. Rotating the front part 541 by 180° to obtain the rear part of the front suspension plate 51 can make the fluid generate negative pre-swirl before flowing to the foremost moving blade 21, thereby improving the efficiency of the axial flow fan 1000. The deflection section 524 of the rear suspension plate 52 is located on the windward side 551 of the rear part of the front suspension plate 51. The slope of the profile tangent in the front suspension plate 51 is negative and the absolute value of the slope gradually increases along the Z direction, which can increase the degree of pre-swirl 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 this embodiment, and the front suspension support plate 51 is set to be located upstream of all blade assemblies 2, the incoming flow in front of the uppermost moving blade 21 can be deflected, so that the incoming flow in front of each moving blade 21 is similar, and the fluid flow at each blade assembly 2 is basically consistent, so as to give full play to the performance of the repeated blade assembly 2 in the axial flow fan 1000.

[0154] 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 flows to the lower moving blade 21, thereby improving the efficiency of the axial flow fan 1000 and achieving sufficient residual velocity recovery through the rear suspension plate 52. Furthermore, when the outlet angle β4 of the stationary blade 22 is set between 5° and 20°, the residual velocity recovery effect of the rear suspension plate 52 is even better.

[0155] Furthermore, when the front suspension plate 51 and the rear suspension plate 52 are set to be 180° rotationally symmetrical, considering the performance of the front suspension plate 51, setting the outlet angle β4 of the stator blade 22 between 0° and 24° ensures that the pre-swirl of the incoming flow in front of the first-stage moving blade 211 is sufficiently large through the front suspension plate 51; it also ensures that the rear suspension plate 52 has a sufficiently good effect on recovering the residual velocity of the fluid flowing out of the downstream stator blade 22; thus making the efficiency of the axial flow fan 1000 sufficiently high; at the same time, it also ensures that the performance of the repeating blade assembly 2 is well utilized. The effect is even better when the outlet angle of the stator blade 22 is between 0° and 18°.

[0156] In a preferred embodiment, the profile of the deflection section 524 on the surface of the equal radius is at least second-order differentiable and streamlined, so that the surface change of the deflection section 524 is gentle. On the one hand, it is easy to process, and on the other hand, it makes the fluid flow gentle.

[0157] In a preferred embodiment, such as Figure 11 In the front part 541, the slope of the tangent line of the windward surface 551 on the surface with equal radius is positive, and the absolute value of the slope remains unchanged or gradually decreases along the Z direction. This makes it convenient to obtain the front part 541 by axial demolding when the rear suspension support plate 52 is cast, which is easy to process.

[0158] In a preferred embodiment, such as Figure 11 The windward side 551 of the front section 541 has a straight section 525, which facilitates processing. Furthermore, the absolute value of the slope of the straight section 525 on the surface of equal radius is between 0° and 10°. With the thickness of the rear suspension plate 52 remaining unchanged, this setting allows T1 to be small enough, thereby making T2 large enough to allow the deflection section 524 to be set on the leeward side 552, thereby improving the effect of fluid residual velocity recovery. Figure 11 The slope of the tangent at point P3-1 on the straight line segment 525 is positive. Furthermore, the effect is better when the absolute value of the slope of the straight line segment 525 on a surface with equal radii is between 0° and 3°. It is understood that the limitations on the structural shape in this invention allow for a predetermined range of processing errors; for example, Figure 11 In the middle, the outline of the leading edge of the front part 541 is a continuous and smooth curve. The length of this part along the axial direction accounts for a small proportion of the total length of the front part 541 and can be ignored. Therefore, it is considered that the windward surface 551 of the front part 541 belongs to the straight line segment 525.

[0159] In a preferred embodiment, such as Figure 11The axial length of the front section 541 is 0.25 to 0.5 times the axial length of the rear suspension plate 52. This means the length comparison is performed on the same plane with equal radii. This configuration serves two purposes: first, it ensures the front section 541 is long enough for effective residual velocity recovery; second, it ensures the front section 541 is short enough to provide sufficient length for the rear section 542. Even if fluid separates from the surface of the rear suspension plate 52 after flowing from the front section 541 to the rear section 542, the rear section 542 has enough length for the fluid to re-attach to the surface of the rear suspension plate 52, thus suppressing separation.

[0160] When the front suspension plate 51 and the rear suspension 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 plate 52. This is to balance the performance of the front suspension plate 51, ensuring that the rear portion of the front suspension plate 51 with the same shape is long enough to suppress separation and produce a sufficiently good pre-rotation effect. In this case, setting the axial length of the front portion 541 to be 0.3 to 0.55 times the axial length of the rear suspension plate 52 yields even better results.

[0161] In a preferred embodiment, such as Figure 11 The rear part 542 is symmetrically arranged about the axis, which makes it easy to process and facilitates the flow of fluid close to the axis.

[0162] In a preferred embodiment, the number of front suspension support plates 51 and rear suspension support plates 52 is the same, both being multiple, and they are evenly spaced around the axial direction, as can be seen from [reference needed]. Figure 3 Furthermore, the average consistency of both types of suspension plates 5 is greater than or equal to 0.7, ensuring that the suspension plates 5 are sufficiently densely spaced to guarantee that the front suspension plate 51 generates pre-rotation and the rear suspension plate 52 achieves sufficient recovery velocity. Average consistency can be understood as the average consistency at different radii. The effect is even better when the average consistency of the suspension plates 5 is greater than or equal to 1.

[0163] like Figure 4 The average distance 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, where i = 1, 2, ..., K. As i increases, drs_i decreases, meaning that the closer to the inlet of the axial flow fan 1000, the larger drs_i becomes. K = 3, and the corresponding drs_i are drs_1, drs_2, and drs_3, where drs_1 > drs_2 > drs_3. The average distance can be understood as the average distance at different radii. In the figure, the distance at a certain blade height is simplified and labeled as the average distance.

[0164] like Figure 6The average distance along the Z-direction between the trailing edge of the j-th stage stationary blade 22 and the leading edge of the (j+1)-th stage moving blade 21 is dsr_j, where j = 1, 2, ..., K-1. As j increases, dsr_j decreases, meaning that the closer to the inlet of the axial flow fan 1000, the larger dsr_j becomes. When K = 3, dsr_j are dsr_1 and dsr_2, respectively, and dsr_1 > dsr_2. In other embodiments, if two-stage blade assemblies 2 are provided, corresponding to one dsr_j, i.e., dsr_1, it can be considered that dsr_j decreases or increases with the number of stages.

[0165] In a range hood 10000, the inlet is generally closer to the user than the outlet. The closer the axial flow fan 1000 is to the inlet, the greater the noise impact on the user. A larger drs_i ensures more uniform mixing of the fluid as it flows from the trailing edge of the moving blade 21 to the trailing edge of the stationary blade 22, thus improving blade frequency noise and reducing fluid flow noise. In a range hood 10000, the closer the drs_i and dsr_j are to the inlet, the larger they are. On one hand, the more uniform the airflow is mixed at the blades closer to the inlet, the lower the noise generated by the airflow itself, and the less noise is transmitted to the user. On the other hand, although a smaller drs_i and dsr_j are closer to the outlet, resulting in greater noise at the downstream blades than at the upstream blades, the closer the axial flow fan 1000 is to the outlet, the greater the noise impact on the user. The farther away from the user, the less impact the noise has on the user. Also, the closer to the outlet of the axial fan 1000, the greater the noise generated by the airflow. When it reaches the inlet of the axial fan 1000, it needs to pass through more rows of blades to be blocked. This causes the noise generated at the downstream blades to gradually weaken as it is transmitted upstream, thereby reducing the noise transmitted to the user. Combining these two aspects, the upstream part of the axial fan 1000, especially at the inlet, has less noise, thus reducing the noise transmitted from the range hood 10000 to the user.

[0166] If the noise level at the inlet of the axial flow fan 1000 is kept consistent, compared to a scheme where all drs_i and dsr_j are the same, this embodiment, by setting drs_i and dsr_j to be larger the closer they are to the inlet of the axial flow fan 1000, facilitates a reduction in the axial dimension of the axial flow fan 1000, resulting in a more compact structure. If the axial dimension of the axial flow fan 1000 is kept constant, compared to a scheme where all drs_i and dsr_j are the same, this embodiment, by setting drs_i and dsr_j to be larger the closer they are to the inlet of the axial flow fan 1000, can significantly reduce the noise at the inlet of the axial flow fan 1000. In the range hood 10000, the inlet of the range hood 10000 is generally closer to the user than the outlet. This makes the upstream blade assembly 2 of the axial flow fan 1000 closer to the user. By setting drs_i and dsr_j to decrease, the noise transmitted from the axial flow fan 1000 to the user can be reduced. At the same time, the compact structure of the axial flow fan 10000 can also be maintained. Thus, the range hood 10000 can achieve both compact structure and low noise.

[0167] In other embodiments, it can be set that as i 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. This can reduce the noise at the inlet or outlet of the axial flow fan 1000, or it can balance the axial dimensions and noise reduction performance of the axial flow fan 1000. 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 all be considered as drs_i and dsr_j changing monotonically in the same direction.

[0168] In other embodiments, the axial flow fan 1000 of this embodiment or other embodiments can be applied to other scenarios besides the range hood 10000.

[0169] 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. This can reduce the noise at the inlet of the axial flow fan 1000, thereby reducing the noise transmitted to the user, or it can balance the axial dimension and noise reduction performance of the axial flow fan 1000. Furthermore, setting drs_1>drs_2>……>drs_K, dsr_1>dsr_2>……>dsr_(K-1) is even more effective.

[0170] In other embodiments, when the outlet of the axial flow fan 1000 is closer to the user than the inlet, such as in air supply equipment like air conditioners or 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, making the noise at the outlet of the axial flow fan 1000 smaller, thereby reducing the noise transmitted to the user. Furthermore, setting drs_1<drs_2<……<drs_K, dsr_1<dsr_2<……<dsr_(K-1) is even better.

[0171] In other embodiments, the primary stationary blade 221 or the moving blade 21 may have only one row of blades; or, multiple rows of blades may be connected in series to form a single moving blade 21 or a single stationary blade 22. In this case, for the primary 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 level, and the trailing edge of the last row of blades is considered to be the trailing edge of the blade of that level.

[0172] 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, by 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; the axial spacing between the j-stage stationary blade 22 and the j+1-stage moving blade 21 can be increased, 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 reducing the overall noise of the axial flow fan 1000.

[0173] In a preferred embodiment, j = i, and the range of dsr_j / drs_i is between 1 and 1.4. This allows the values ​​of dsr_j and drs_i to be large enough to reduce the noise of the axial fan 1000, while also ensuring that dsr_j and drs_i are small enough to prevent the axial dimension of the axial fan 1000 from being too large.

[0174] Example 2

[0175] This embodiment provides an axial flow fan. The main difference between the axial flow fan in this embodiment and that in Embodiment 1 is the shape of the suspension support plate. The housing, rotating shaft, blade assembly, and mounting components are set up in the same way as in Embodiment 1. For details, please refer to Embodiment 1. Figures 12-14 This is a schematic diagram of this embodiment.

[0176] In this embodiment, the front suspension support plate 51 and the rear suspension support plate 52 are rotationally symmetrical at 180°. In this embodiment, the outer support portion 531 of the rear suspension support plate 52 has the same shape as in Embodiment 1, but the shape of the inner support portion 532 of the rear suspension support plate 52 is different from that in Embodiment 1; in Embodiment 1, the inner support portion 532, i.e., the third portion 513, has one part belonging to the front portion 541 and the other part belonging to the rear portion 542, meaning the thickness of the inner support portion 532 gradually increases and then gradually decreases along the Z-direction; as... Figure 12 In this embodiment, the thickness of the inner support portion 532 in the rear suspension support plate 52 gradually decreases along the Z direction, and the absolute value of the slope of the tangent line of the windward side 551 and the leeward side 552 of the inner support portion 532 in the plane of equal radius gradually increases. In other embodiments, this slope can remain unchanged or gradually increase, forming a natural draft angle. Figure 12 The dashed line L2 represents the outline of the rear mounting component 42. This configuration is as follows: Figure 13 , Figure 14 According to Table 2, the fifth part 522 and the sixth part 523 of the rear suspension support plate 52 can be cast together as the second casting part 562. Figure 14 Using 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 plates 52, and the mold is pulled out along the S1 direction to 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 form the second casting part 562; S1 and S2 are axial; furthermore, they can be set to be parallel to the Z direction.

[0177] Table 2. Division of Casting Locations for Suspended Support Plate 5

[0178]

[0179] Furthermore, such as Figure 13 The outer diameter of the rear mounting member 42 gradually decreases along the Z-direction, resulting in a smooth transition in the surface shape of the rear mounting member 42, which is convenient for processing, especially for casting. Furthermore, 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 member 42, both being the minimum radius r1 of the downstream end of the blade flow channel 6. This facilitates the integral processing and molding of the rear suspension support plate 52 and the rear mounting member 42. In this embodiment, the rear suspension support plate 52 and the rear mounting member 42 can be integrally cast. In addition, the upstream end of the rear mounting member 42 has the same diameter as the blade flow channel 6, which allows the fluid to flow smoothly from the blade assembly 2 to the rear mounting member 42 and then smoothly over the rear mounting member 42, reducing fluid flow dynamic loss.

[0180] Example 3

[0181] This embodiment provides an axial flow fan. The main difference between the axial flow fan in this embodiment and those in embodiments 1 and 2 is the shape of the suspension support plate. The housing, rotating shaft, blade assembly, and mounting components are set up in the same way as in embodiment 2. For details, please refer to embodiments 1 and 2. Figures 15-16 This is a schematic diagram of this embodiment.

[0182] In this embodiment, the front suspension plate 51 and the rear suspension plate 52 are rotationally symmetrical at 180°. The inner support portion 532 of the rear suspension plate 52 has the same shape as in Embodiment 2, but the outer support portion 531 of the rear suspension plate 52 has a different shape. In this embodiment, the front portion 541 of the outer support portion 531 of the rear suspension plate 52, i.e., the fourth portion 521, has a windward surface 551 with a straight line segment 525. The slope of this segment on the surface of equal radius is negative, and the absolute value of the slope remains constant along the Z-direction. For example... Figure 15 The slope of the tangent at point P3-2, as shown in the diagram, is negative. In other embodiments, the slope of the tangent of the windward surface 551 of the fourth part 521 on the surface with equal radius can be set to be negative, and the absolute value of the slope remains unchanged or gradually decreases. Figure 15 In the middle, the dashed 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 between the thickness of the windward side 551 and the leeward side 552 of the rear suspension plate 52. The thickness of the windward side 551 of the front part 541 is missing, and the thickness T1 can be considered to be negative. 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 of the leeward side.

[0183] In this embodiment, the tangent slope of the profile of the windward side 551 of the fourth part 521 on the plane of equal radius is negative, and the front part 541 of the rear suspension plate 52 is offset to a greater extent towards the leeward side 552, which can further improve the effect of the fourth part 521 on recovering the residual velocity of the incoming flow. The front suspension plate 51 and the rear suspension plate 52 are arranged with 180° rotational symmetry. The fourth part 521, relative to the second part 512 of the front suspension plate 51, can improve the degree to which the second part 512 causes the fluid to pre-swirl.

[0184] like Figure 16 The rear suspension support plate 52 is cast using two types of molds, with L-S2 as the parting line. Figure 16 The tail edge of the upper rear suspension plate 52 and the front edge of the lower rear suspension plate 52 are located at both ends of L-S2; a mold is placed on the left side of L-S2 between the two rear suspension plates 52, and the mold is rotated along the axial direction for demolding. S3 is an angle diagram during the demolding process; another mold is placed on the right side of L-S2, and the mold is demolded along the S4 direction. S4 is along the axial direction; furthermore, S4 can be set to be parallel to the Z direction.

[0185] Overall, the axial flow fan 1000 provided by this invention has the following advantages:

[0186] 1. The axial flow fan 1000 is small in size and occupies little space when used in the range hood 10000. Its layout in the air duct is flexible and free, which facilitates noise reduction design. Because the axial flow fan 1000 has the characteristic of straight airflow, it is very easy to stack multiple stages without bringing high complexity to the structure. When applied to the range hood 10000, multi-stage blade assembly 2 is set to distribute the pressure rise, thereby achieving a significant reduction in noise.

[0187] 2. The blades of the axial flow fan 1000 are usually twisted, which causes inconvenience in processing. This invention improves the problem of high processing cost of the axial flow fan 1000 through the following aspects:

[0188] 2-1. The moving blades 21 and stationary blades 22 are the same for each stage. The blade mold of the whole 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 and reduce processing costs.

[0189] 2-2. Use softer materials such as plastic or aluminum alloy to make the blades, thereby reducing mold wear;

[0190] 2-3. By setting the blade consistency, it is easy for the blade to rotate bidirectionally for demolding;

[0191] 2-4. The moving blades 21 of each stage have the same shape and size, and the stationary blades 22 of each stage have the same shape and size, so as to reduce the manufacturing cost of the axial flow fan 1000 and make it easy to increase or decrease the number of stages of the blade assembly 2 to adjust the performance of the axial flow fan 1000.

[0192] 2-5. The multi-stage blade assembly 2 is set up to achieve the target pressure rise, so the load on each stage blade assembly 2 is relatively light and the degree of blade twist is relatively low, which also reduces the processing difficulty.

[0193] 3. In the axial flow fan 1000, which has multiple blade assemblies 2 in the range hood 10000, the aerodynamic noise of the first-stage blade assembly 2 is directly transmitted to the inlet of the range hood 10000. However, the aerodynamic noise of subsequent blade assemblies 2 is blocked by several rows of blades before reaching the inlet of the range hood 10000, and the noise transmitted from the later stages is blocked by more blades. Therefore, the earlier stages contribute more to the noise perceived by the user. Therefore, in the range hood of this invention, both drs_i and dsr_j decrease as the number of stages increases, thereby weakening the pulsating noise generated at the upstream blade assembly 2 and reducing the overall noise perceived by the user. Furthermore, by adjusting the values ​​of drs_i / dsr_j to properly allocate the axial spacing, the noise of the axial flow fan 1000 is further reduced.

[0194] 4. By setting the blade shape of the rear suspension plate 52, the residual velocity of the fluid flowing out of the blade assembly 2 is recovered, which improves 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 plate 52, the rear suspension plate 52 can form a natural draft angle, which is convenient for casting.

[0195] 5. By setting the front suspension plate 51 and the rear suspension plate 52 to be rotationally symmetrical, the front suspension plate 51 causes the incoming flow in front of the blade assembly 2 to pre-rotate, thereby improving the efficiency of the axial flow fan 1000. At the same time, the two types of suspension plates 5 can be processed using the same process, which helps to reduce costs.

[0196] While specific embodiments of the present invention have been described above, those skilled in the art should understand that these are merely illustrative examples, and the scope of protection of the present invention is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but all such changes and modifications fall within the scope of protection of the present invention.

Claims

1. An axial flow fan, comprising: case; The rotating shaft is disposed within the housing; At least one blade assembly is disposed within the blade flow channel; The axial flow fan is characterized in that it further includes a rear suspension support plate and a rear mounting component disposed within the housing, the rear mounting component being disposed downstream of the rotating shaft and rotatably connected to the rotating shaft, and the rear suspension support plate being located downstream of the blade assembly and fixed to the rear mounting component and the housing respectively; The rear suspension plate has a front portion that extends axially toward the outlet of the axial flow fan in a first direction and forms the leading edge of the rear suspension plate. The thickness of the front portion gradually increases along the first direction. The rear suspension plate has an outer support portion with a radius greater than or equal to the minimum radius of the downstream end of the blade flow channel. The thickness of at least the windward side of the outer support portion in the front portion is less than the thickness on the leeward side. The slope of the tangent of the leeward side on the plane of equal radius is negative. At least a portion of the leeward side is a deflection section. The absolute value of the slope of the tangent of the deflection section on the plane of equal radius gradually decreases along the first direction.

2. The axial flow fan as described in claim 1, characterized in that, The profile of the deflection section on the equal radius surface is at least second-order differentiable.

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

4. The axial flow fan as described in claim 1, characterized in that, At least the outer support portion of the front section has a straight section on its windward side, and the absolute value of the slope of the straight section on the surface of equal radius is less than or equal to 3°.

5. The axial flow fan as described in claim 1, characterized in that, The rear suspension plate also includes a rear portion, which extends along a first direction and forms the tail edge of the rear suspension plate, and the thickness of the rear portion gradually decreases along the first direction.

6. The axial flow fan as described in claim 5, characterized in that, The axial length of the front part is 0.25 to 0.5 times the axial length of the rear suspension plate; And / or, the rear portion is arranged symmetrically about the axis.

7. The axial flow fan as described in claim 1 or 5, characterized in that, The axial flow fan also includes a front suspension support plate and a front mounting component disposed within the housing. The front mounting component is disposed upstream of the rotating shaft and rotatably connected to the rotating shaft. The front suspension support plate is located upstream of the blade assembly and is fixed to the front mounting component and the housing, respectively. The front suspension plate and the rear suspension plate are arranged in a 180° rotational symmetry configuration; and / or, the front mounting component and the rear mounting component are arranged in a 180° rotational symmetry configuration.

8. The axial flow fan as described in claim 7, characterized in that, The blade assembly includes 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 located upstream of the stationary blade. The absolute value of the exit angle of the moving blade is greater than the absolute value of the exit angle of the stationary blade, and the exit angle of the stationary blade is between 0° and 24°.

9. The axial flow fan as described in claim 8, characterized in that, The exit angle of the stationary blade is between 0° and 18°.

10. The axial flow fan as described in claim 7, characterized in that, At least the outer support portion of the front part has a straight section on its windward side, and the slope of the straight section on the surface of the equal radius 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 plate.

11. The axial flow fan as described in claim 7, characterized in that, The axial length of the front part is 0.3 to 0.55 times the axial length of the rear suspension plate.

12. The axial flow fan as described in claim 1, characterized in that, The rear suspension plate also includes an inner support portion with a radius smaller than the minimum radius of the downstream end of the blade flow channel, and the rear mounting component is installed on at least the inner support portion.

13. The axial flow fan as described in claim 12, characterized in that, The outer diameter of the rear mounting component 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 of the root of the rear suspension plate is equal to the minimum radius at the downstream end of the blade channel.

14. The axial flow fan as described in claim 13, characterized in that, The rear suspension plate also includes a rear portion, which extends along a first direction and forms the tail edge of the rear suspension plate. The thickness of the rear portion gradually decreases along the first direction. The front portion and the rear portion are connected. The rear suspension plate is formed by casting. The slopes of the tangent lines on the windward and leeward sides of the outer support portion in the rear section are negative and positive, respectively, on the plane of equal radius. The slope of the tangent line of the windward surface of the front part on the plane of equal radius is positive. The front part is obtained by drafting along the axial direction using the dividing line between the front part and the rear part as the parting line.

15. The axial flow fan as described in claim 14, characterized in that, The slopes of the tangent lines on the windward and leeward sides of the inner support portion on the plane of equal radius are negative and positive, respectively. The rear portion of the inner support portion and the rear mounting component of the outer support portion are obtained by axial demolding as the same casting module.

16. The axial flow fan as described in claim 1, characterized in that, The number of 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.

17. The axial flow fan as described in claim 16, characterized in that, The average consistency of the rear suspension plate is greater than or equal to 1.

18. The axial flow fan as described in claim 1, characterized in that, The axial flow fan includes multiple stages of blade assemblies, which are arranged sequentially along a first direction. Each blade assembly includes a moving blade mounted on the rotating shaft and a stationary blade mounted on the housing.

19. The axial flow fan as described in claim 18, characterized in that, All moving blades have the same shape and size; all stationary blades have the same shape and size. And / or, in the single-stage blade assembly, the moving blade is positioned upstream of the stationary blade, the absolute value of the exit angle of the moving blade is greater than the absolute value of the exit angle of the stationary blade, and the exit angle of the stationary blade is between 0° and 40°.

20. The axial flow fan as described in claim 18, characterized in that, All moving blades have the same shape and size, and all stationary blades have the same shape and size. The materials of the stationary blades and the moving blades are plastic or aluminum alloy. And / or, in the single-stage blade assembly, the moving blade is positioned upstream of the stationary blade, the absolute value of the exit angle of the moving blade is greater than the absolute value of the exit angle of the stationary blade, and the exit angle of the stationary blade is between 5° and 20°.

21. The axial flow fan as described in claim 1, characterized in that, The minimum and maximum radii of the blade flow channel remain constant along the first direction.

22. The axial flow fan as described in claim 21, characterized in that, The axial length of the rotating shaft completely covers the axial length of the blade assembly, and the blade flow channel is formed between the inner surface of the housing and the outer surface of the rotating shaft.

23. The axial flow fan as described in claim 21, characterized in that, 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 sequentially; The blade assembly includes 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 located upstream of the stationary blade. The average distance along the axial direction between the trailing edge of the i-th stage moving blade and the leading edge of the i-th stage stationary blade is drs_i, i = 1, 2, ..., K; the average distance along the axial direction between the trailing edge of the j-th stage stationary blade and the leading edge of the (j+1)-th stage moving blade 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.

24. The axial flow fan as described in claim 23, characterized in that, dsr_j≥drs_i, j=i; and / or, dsr_j>drs_(i+1), j=i.

25. The axial flow fan as described in claim 24, characterized in that, The range of dsr_j / drs_i is between 1.1 and 1.5, where j = i.

26. A range hood, characterized in that, It includes an axial flow fan as described in any one of claims 1-22, 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.

27. A range hood, characterized in that, It includes an axial flow fan as described in any one of claims 23-25, 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, drs_1≥drs_2≥……≥drs_K, dsr_1≥dsr_2≥……≥dsr_(K-1).

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