Axial flow fan assembly and air conditioner

Abstract

The present invention discloses an axial flow fan assembly and an air conditioner. Among them, the axial flow fan assembly includes an air outlet cylinder, the air outlet cylinder has a front port and a rear port, and the axial flow fan assembly further includes: a guide ring, the guide ring is installed at the rear port of the air outlet cylinder, the diameter of the air outlet cylinder is 250mm ≤ d0 ≤ 450mm, the axial width of the guide ring is m, 20mm ≤ m ≤ 80mm, and the radial distance between the rear end of the guide ring and the rear end of the air outlet cylinder is d1, 10mm ≤ d1 ≤ 50mm. The technical solution of the present invention reduces the noise during the operation of the axial flow fan assembly.

Description

Technical Field

[0001] The present invention relates to the technical field of air conditioners, and particularly to an axial flow fan assembly and an air conditioner including the axial flow fan assembly. Background Art

[0002] The axial flow fan assembly has one axial flow impeller or two axial flow impellers inside, or more than two axial flow impellers. For an axial flow fan provided with two or more axial flow impellers, when operating, the air output is relatively large.

[0003] In some existing air conditioner indoor units, an axial flow fan assembly is installed. Since the axial flow fan assembly itself inevitably generates relatively large noise during operation. Summary of the Invention

[0004] The main object of the present invention is to provide an axial flow fan assembly, aiming to solve the problem of large noise during the operation of an air conditioner indoor unit.

[0005] To achieve the above object, an axial flow fan assembly proposed by the present invention includes an air outlet cylinder and at least one blade installed on the air outlet cylinder. The air outlet cylinder has a front port and a rear port. It is characterized in that the axial flow fan assembly further includes:

[0006] A guide ring, the guide ring is installed at the rear port of the air outlet cylinder, and the guide ring is flared backward;

[0007] The diameter of the air outlet cylinder is 250mm ≤ d0 ≤ 450mm, the axial width of the guide ring is m, 20mm ≤ m ≤ 80mm, and the radial distance between the rear end of the guide ring and the rear end of the air outlet cylinder is d1, 10mm ≤ d1 ≤ 50mm.

[0008] Preferably, it is characterized in that 300mm ≤ d0 ≤ 400mm.

[0009] Preferably, 30mm ≤ m ≤ 60mm.

[0010] Preferably, 30mm ≤ d1 ≤ 40mm.

[0011] Preferably, the inner wall surface of the guide ring is arranged as an arc surface convex outward backward.

[0012] Preferably, the inner wall surface of the guide ring is tangent to the inner wall surface of the air outlet cylinder.

[0013] Preferably, the curvature of the inner wall surface of the guide ring gradually decreases backward.

[0014] Preferably, the line segment of the inner wall surface of the guide ring intercepted by a plane parallel to the axis of the guide ring includes a plurality of arc segments arranged backward, and the plurality of arc segments are connected in sequence.

[0015] Preferably, the line segment of the inner wall surface of the flow guiding ring intercepted by a plane parallel to the axis of the flow guiding ring includes a plurality of arc segments and straight segments arranged backward, wherein the arc segments are arranged as an arc surface convex outward backward, the arc segments are connected to the rear end of the air outlet cylinder, and the arc segments and the straight segments are arranged alternately.

[0016] Preferably, the number of the air foils in the air outlet cylinder is multiple, and the multiple air foils are arranged at intervals along the axial direction of the air outlet cylinder.

[0017] Preferably, the number of the air foils is two, and the two air foils are a front air foil and a rear air foil. The rotation direction when the front air foil blows the air flow towards the air outlet is opposite to the rotation direction when the rear air foil blows the air flow towards the air outlet.

[0018] Preferably, at least a part of the rear air foil is located in the air outlet cylinder. The maximum axial distance between the leading edge of the rear vane and the air inlet is d2, and the blade height of the rear vane is d3, where d3 / 3 ≤ d2 ≤ 4d3 / 3.

[0019] The present invention further provides an air conditioner, which includes an axial flow fan assembly. The axial flow fan assembly includes an air outlet cylinder and at least one air foil installed on the air outlet cylinder. The air outlet cylinder has a front port and a rear port. The axial flow fan assembly further includes:

[0020] A flow guiding ring, which is installed at the rear port of the air outlet cylinder and is flared backward;

[0021] The diameter d0 of the air outlet cylinder satisfies 250 mm ≤ d0 ≤ 450 mm. The axial width of the flow guiding ring is m, where 20 mm ≤ m ≤ 80 mm. The radial distance between the rear end of the flow guiding ring and the rear end of the air outlet cylinder is d1, where 10 mm ≤ d1 ≤ 50 mm;

[0022] The air conditioner includes an indoor unit of the air conditioner and an outdoor unit of the air conditioner. The axial flow fan assembly is placed in the indoor unit of the air conditioner, and the indoor unit of the air conditioner is a floor-mounted indoor unit of the air conditioner or a ceiling-mounted unit or a wall-mounted indoor unit of the air conditioner; and / or,

[0023] The axial flow fan assembly is placed in the outdoor unit of the air conditioner.

[0024] Preferably, the indoor unit of the air conditioner includes a housing and a heat exchanger. The housing has an air inlet and an air outlet. The heat exchanger is arranged corresponding to the air inlet. The axial flow fan assembly is installed between the heat exchanger and the air outlet. The distance between the rear vane and the heat exchanger is d4, where 30 mm ≤ d4 ≤ 120 mm.

[0025] Preferably, 60 mm ≤ d4 ≤ 80 mm.

[0026] Preferably, the axial flow fan assembly is the first fan, and a second fan is further provided in the air conditioner. Both the first fan and the second fan are provided in the indoor unit of the air conditioner, and 30 mm ≤ d4 ≤ 40 mm; or,

[0027] Both the first fan and the second fan are provided in the outdoor unit of the air conditioner, and 30 mm ≤ d4 ≤ 40 mm.

[0028] Preferably, the second fan is an axial flow fan, a centrifugal fan or a cross-flow fan.

[0029] By limiting the diameter d0 of the air outlet cylinder of the axial flow fan assembly to 250 mm ≤ d0 ≤ 450 mm, the axial width m of the guide ring to 20 mm ≤ m ≤ 80 mm, and the radial distance d1 between the rear end of the guide ring and the rear end of the air outlet cylinder to 10 mm ≤ d1 ≤ 50 mm, the technical solution of the present invention greatly reduces the noise generated during the operation of the axial flow fan assembly. Description of the Drawings

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on the structures shown in these drawings.

[0031] Figure 1 It is a schematic assembly structure diagram of the first embodiment of the axial flow fan assembly of the present invention in the indoor unit of the air conditioner;

[0032] Figure 2 It is a schematic assembly structure diagram of the second embodiment of the axial flow fan assembly of the present invention in the indoor unit of the air conditioner;

[0033] Figure 3 It is a schematic assembly structure diagram of the third embodiment of the axial flow fan assembly of the present invention in the indoor unit of the air conditioner;

[0034] Figure 4 It is a schematic assembly structure diagram of the fourth embodiment of the axial flow fan assembly of the present invention in the indoor unit of the air conditioner;

[0035] Figure 5 It is a schematic assembly structure diagram of the fifth embodiment of the axial flow fan assembly of the present invention in the indoor unit of the air conditioner;

[0036] Figure 6 It is a schematic assembly structure diagram of the sixth embodiment of the axial flow fan assembly of the present invention in the indoor unit of the air conditioner;

[0037] Figure 7Schematic diagram of the assembly structure of the seventh embodiment of the axial flow fan assembly of the present invention in an air conditioner indoor unit;

[0038] Figure 8 Schematic diagram of the assembly structure of the eighth embodiment of the axial flow fan assembly of the present invention in an air conditioner indoor unit.

[0039] Explanation of the reference numerals in the drawings:

[0040] Reference numeral Name Reference numeral Name 11 Air outlet duct 121a Front motor 122a Front air blade 123a Front support 121b Rear motor 122b Rear air blade 123b Rear support 13 Flow guide ring 21 Outer shell 21a Front panel 21b Back panel 30 Heat exchanger

[0041] The realization, functional features and advantages of the object of the present invention will be further described with reference to the embodiments and the accompanying drawings. Detailed implementation manners

[0042] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0043] It should be noted that all directional indications (such as up, down, left, right, front, back,...) in the embodiments of the present invention are only used to explain the relative positional relationship and movement conditions between components in a specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indications will also change accordingly.

[0044] In addition, the descriptions involving "first", "second", etc. in the present invention are only for descriptive purposes, and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In addition, the technical solutions between various embodiments may be combined with each other, but it must be based on the fact that those of ordinary skill in the art can implement them. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope required by the present invention.

[0045] The present invention actually proposes an axial flow fan assembly, an air conditioner indoor unit including the axial flow fan assembly, and an air conditioner including the air conditioner indoor unit. The air conditioner indoor unit may specifically be a floor-standing air conditioner indoor unit or a ceiling cassette, etc. The following content will be introduced with a floor-standing air conditioner indoor unit as a specific embodiment.

[0046] Please refer to Figure 1 , the present invention proposes an axial flow fan assembly. The axial flow fan assembly includes an air outlet cylinder 11. The air outlet cylinder 11 has a front port and a rear port. The axial flow fan assembly further includes:

[0047] A flow guide ring 13, the flow guide ring 13 is installed at the rear port of the air outlet cylinder 11, and the flow guide ring 13 is flared backward.

[0048] The diameter d0 of the air outlet cylinder 11 satisfies 250mm ≤ d0 ≤ 450mm, for example, d0 = 280mm, 300mm, 330mm, 350mm, 380mm, 400mm, 420mm or 440mm. Of course, preferably, d0 ∈ [300mm, 400mm] here.

[0049] Specifically, the axial flow fan assembly can be a single-stage axial flow fan (with only one blade), or a multi-stage axial flow fan (there are multiple blades arranged in the air outlet cylinder, such as 2 blades, 3 blades, or even more blades, and the multiple blades are spaced along the axial direction of the air outlet cylinder). For a multi-stage axial flow fan, the following embodiments will specifically take a contra-rotating fan as an example for elaboration. For a contra-rotating fan, a front blade and a rear blade are arranged in the air outlet cylinder, and the rotation direction of the front blade when blowing the air flow towards the air outlet is opposite to the rotation direction of the rear blade when blowing the air flow towards the air outlet.

[0050] The axial flow fan assembly includes an air outlet cylinder 11, a flow guide ring 13, a front blade 122a, a front bracket 123a, a front motor 121a, a rear blade 122b, a rear bracket 123b, and a rear motor 121b. Both ends of the air outlet cylinder 11 are open, that is, a front port and a rear port are formed. The flow guide ring 13 is installed at the rear port. The connection method between the flow guide ring 13 and the air outlet cylinder 11 can be welding, or integrally formed, or inserted, or internal threads are formed in the air outlet cylinder 11, external threads are formed on the flow guide ring 13, and the two are screwed and matched.

[0051] The rear bracket 123b can be installed inside the air outlet cylinder 11 or inside the flow guide ring 13. The rear bracket 123b can be fixed to the air outlet cylinder 11 or fixed to the flow guide ring 13. The rear motor 121b is installed on the rear bracket 123b, and the rear blade 122b is installed on the rear motor 121b. The front bracket 123a is installed at the front port of the air outlet cylinder 11. The front motor 121a is installed on the front bracket 123a.

[0052] The radius of the rear port of the air outlet tube 11 is R1, and the radius of the rear port of the guide vane ring 13 is R2 (it should be noted that the radius of the front port of the guide vane ring 13 is equal to the radius of the rear port of the air outlet tube 11), and d1 = R2 - R1. For the case where d1 = 0, that is, when the guide vane ring 13 is arranged in a straight tube shape. In addition, the width of the guide vane ring should not be too large. If it is too large, the curvature of the inner wall surface of the guide vane ring will be too small, thus affecting the air guiding effect; the width of the guide vane ring should not be too small either. If it is too small, the curvature of the inner wall surface of the guide vane ring will be too large, that is, the flaring amplitude is too large, and thus it is also not conducive to air guiding.

[0053] In order to test the value range of the width of the guide vane ring,

[0054] The following experiment is conducted with d1 = 10 mm:

[0055] Table A

[0056]

[0057] The following experiment is conducted with d1 = 50 mm:

[0058] Table B

[0059]

[0060]

[0061] The following experiment is conducted with d1 = 80 mm:

[0062] Table C

[0063]

[0064] As can be seen from the above Tables A to C, when d1 is between 10 mm and 50 mm, and m is between 20 mm and 80 mm, the overall noise is relatively at a low level.

[0065] It should be noted that the measurement method of d1 is as follows: ① Measure the radii of both ports of the guide vane ring; ② Subtract the two measured radius values and take the absolute value to obtain the d1 value. The measurement method of the m value is as follows: ① Take 5 points on the circumference of the air outlet of the guide vane ring, and the 5 points are equally spaced in the circumferential direction of the outlet; ② Measure the vertical distances from the 5 points to the plane where the air inlet of the guide vane ring is located respectively; ③ Take the average value of the above 5 vertical distances to obtain the m value.

[0066] To test the influence of d1 on the noise of the axial flow fan assembly, taking the diameter of the air outlet tube 11 as 360 mm, the air volume of 1200 cubic meters, and the width m of the guide vane ring 13 as 30 mm as an example for testing, the experiment is as follows:

[0067] Table 1

[0068]

[0069]

[0070] To test the influence of the noise of the d1 axial flow fan assembly, taking the diameter of the air outlet cylinder 11 as 360 mm, the air volume of 1200 m³ / h, and the width m of the flow guide ring 13 as 60 mm as an example for testing, the experiment is as follows:

[0071] Table 2

[0072]

[0073] For d1, on the one hand, considering the volume manufacturing of the axial flow fan assembly, d1 should not be too large. If d1 is too small, it will also lead to poor noise reduction effect. Therefore, d1 should not be too small either.

[0074] As can be seen from Table 1, when d1 = 0, the noise value is relatively high, reaching 48.7 dB. During the process of d1 increasing from 0 to 40 mm, the noise value gradually decreases. When d1 increases to 40 mm, the noise value reaches the lowest 45.1 dB.

[0075] When the value of d1 continues to increase, the noise value instead increases.

[0076] Analysis: When d1 = 0, when the air flow enters the guide cylinder, the turning angle of the external air flow entering the flow guide ring 13 is relatively large and rapid (the surrounding air flow turns by 90° to enter the flow guide ring 13), resulting in a large loss of air flow energy and thus bringing relatively high noise.

[0077] When d1 is in the range of 10 mm to 40 mm, under the guiding action of the flow guide ring 13, the air flow flows into the flow guide ring 13 relatively smoothly and there is no sharp turning situation during the inflow. Therefore, the loss of air flow energy is small. In addition, due to the air flow flowing along with the flow guide ring 13, the generated eddy current effect is also relatively low.

[0078] When d1 continues to increase, the rear port of the flow guide ring 13 is relatively large and the front port is relatively small. A large amount of external air flow converges from the rear port to the front port, but the capacity of the front port is limited, so part of the air flow cannot pass through the front port in time, resulting in the formation of an eddy current between the front port and the rear port, and further causing the noise to increase greatly again.

[0079] As can be seen from Table 1, when d1 is between 30 mm and 40 mm, the noise value is at a relatively low level.

[0080] Based on the same analysis, as can be seen from Table 2, when d1 is between 30 mm and 50 mm, the noise value is at a relatively low level. Therefore, when the thickness of the flow guide ring 13 is in the range of 30 mm to 50 mm and d1 is between 30 mm and 40 mm, the axial flow fan assembly can maintain a relatively low noise.

[0081] Please refer to Figures 2 to 8 In the above embodiments, the inner wall surface of the flow guide ring 13 can be set with a flared straight surface, or can be set with a flared convex arc surface, or can be set with a flared concave arc surface, or can also be composed of a convex arc surface and a straight surface. Of course, for the inner wall surface with a flared straight surface, after the air flow flows from the rear port of the flow guide ring 13 to the front port, the air flow has to flow into the air outlet cylinder 11. However, at this time, the corner at the connection between the inner wall surface of the flow guide ring 13 and the air outlet cylinder 11 is relatively large. When the air flow passes through this position, the air flow velocity loss is relatively serious, and the vortex phenomenon is also relatively serious (a convex arc surface can be set between the straight surface and the air outlet cylinder 11 to slow down the vortex situation formed when the air flow flows into the flow guide cylinder). For the inner wall surface with a flared concave arc surface, the air flow velocity loss phenomenon is even greater, and the vortex phenomenon is also more serious. Based on this, in this embodiment, the inner wall surface of the flow guide ring 13 is set with a flared arc surface convex outward backward.

[0082] In the above embodiments, in order to make the air flow more smooth, the inner wall surface of the flow guide ring 13 is tangent to the inner wall surface of the air outlet cylinder 11.

[0083] Please refer to Figure 3 In a preferred embodiment, in order to make the noise lower, the curvature of the inner wall surface of the flow guide ring 13 gradually decreases backward.

[0084] For the case where the curvature of the inner wall surface of the flow guide ring 13 remains unchanged backward, the curvature cannot be too large. Otherwise, once the width of the flow guide ring 13 is relatively large, when the air flow flows from the rear port of the flow guide ring 13 to the front port, the flow direction needs to be adjusted greatly, which will cause the air flow to be subject to a relatively large resistance, and thus the formed noise is relatively large.

[0085] In view of this, in this embodiment, by setting the curvature of the inner wall surface to gradually decrease backward, thus, when the air flow flows from the rear port of the flow guide ring 13 to the front port, the resistance suffered by the air flow is relatively small, and the noise is also relatively low.

[0086] Please refer to Figure 5 Different from the previous embodiment, in another preferred embodiment, in order to make the air flow flow relatively smoothly when the flow guide ring 13 guides the air flow, the line segment of the inner surface of the flow guide ring 13 intercepted by a plane parallel to the axis of the flow guide ring 13 includes a plurality of arc segments arranged backward with gradually increasing diameters, and the plurality of arc segments are connected in sequence.

[0087] In the previous embodiment, the curvature of the inner wall surface of the flow guide ring 13 gradually decreases backward. In this embodiment, the curvature of the inner wall surface of the flow guide ring 13 decreases in a stepped manner backward. For example, the inner wall surface of the flow guide ring 13 includes three arc segments arranged backward, and the curvature radii of the three arc segments are r1, r2, and r3 respectively, where r1 < r2 < r3.

[0088] Please refer to Figure 4 and Figure 6 Similarly, in order to make the air flow smoothly when the flow guiding ring 13 guides the air flow, the line segment of the inner surface of the flow guiding ring 13 intercepted by a plane parallel to the axis of the flow guiding ring 13 includes a plurality of arc segments and straight segments arranged backward. The arc segments are connected to the rear end of the air outlet cylinder 11, and the arc segments and the straight segments are arranged alternately.

[0089] For this case, the sum of the number of arc segments and straight segments is greater than or equal to 3, that is, arc segment - straight segment - arc segment - straight segment... The inner wall surface of the last section of the flow guiding ring 13 can be arranged as the above-mentioned straight segment or as the above-mentioned arc segment. Of course, in order to make the air flow into the flow guiding ring 13 more smoothly, it is better that the inner wall surface of the last section of the flow guiding ring 13 is arranged as an arc segment.

[0090] When the air flow enters the flow guiding ring 13, there is an attachment effect, so part of the air flow will flow along the inner wall surface of the flow guiding ring 13. For the air flow attachment, the flat straight surface attachment is the best, and the arc surface is relatively poor.

[0091] When the value of d1 is fixed, if the entire inner wall surface is arranged as an arc segment, the overall curvature of the arc segment cannot be too large, otherwise, it will also cause a relatively serious eddy current phenomenon; the curvature of the arc segment cannot be too small, otherwise the resistance of the air flow entering the flow guiding ring 13 is too large, and finally the noise will also be too large. Even if the curvature is set appropriately (neither too large nor too small, between the straight line and the semi-circular arc of two points), due to the poor air flow attachment effect, finally, the formed eddy current effect is not ideal.

[0092] In this embodiment, the inner wall surface of the flow guiding ring 13 is arranged with arc segments and straight segments alternately. On the one hand, the above-mentioned curvature problem is solved (whether the curvature is large or small, the noise is relatively large). On the other hand, when the air flow flows along the inner wall of the flow guiding ring 13, since the air flow flows from the arc segment to the straight segment (or from the straight segment to the arc segment), the curvature of the arc segment is small and the line segment is short, and its attachment effect is good. When it transitions to the straight segment, the attached air flow will not have too much wall detachment phenomenon. Generally speaking, this setting method of the flow guiding ring 13 in this embodiment makes a further contribution to the reduction of noise.

[0093] Please refer to Figure 2 and Figure 7 In a preferred embodiment, the maximum axial distance between the leading edge of the rear blade and the edge of the air inlet is d2, and the height of the rear blade (the height of the blade in the axial direction of the air outlet cylinder 11) is d3, and d3 / 3 ≤ d2 ≤ 4d3 / 3.

[0094] Here, the position of the rear wind blade 122b at the air outlet duct 11 also affects the air outlet noise. Here, to verify this effect, the experiment is as follows:

[0095] Taking the air outlet duct 11 with a diameter of 360 mm, an air volume of 1200 cubic meters, the width of the flow guide ring 13 being 30 mm, and the inner wall surface of the flow guide ring 13 being convex arc-shaped backward as an example for testing:

[0096] Table 3

[0097]

[0098] It can be seen from Table 3 that when d2 = 0, the noise of the axial flow fan assembly is relatively large, reaching 54.6 dB, and as the rear wind blade 122b extends in, the noise value gradually decreases. This is because when d2 = 0, the gap between the rear wind blade 122b and the flow guide ring 13 is relatively large, and the air flow generates eddy currents in this gap, forming wind resistance and causing noise. As the rear wind blade 122b extends in, the average distance between the rear wind blade 122b and the flow guide ring 13 and the inner wall of the air outlet duct gradually decreases, thereby reducing the eddy current effect and the noise also decreases. It can be seen from the table that when d2 increases from d3 / 4 to d3 / 3, the noise reduction reaches 2.4 dB. The reasons may be as follows:

[0099] When d2 = d3 / 4, 3d3 / 4 of the rear wind blade 122b is located in the flow guide ring 13 (hereinafter referred to as the 3d3 / 4 part, and the 1d3 / 4 of the rear wind blade 122b located in the air outlet duct 11 is referred to as the d3 / 4 part). Due to the different distances between the rear wind blade 122b and the flow guide ring 13, and between the rear wind blade 122b and the air outlet duct 11, the 3d3 / 4 part generates a relatively high vibration frequency when rotating, while the d3 / 4 part generates a relatively low vibration frequency by itself. However, the two are fixedly connected together, so ultimately the vibration frequency depends on the 3d3 / 4 part, resulting in relatively large noise. When d2 = d3 / 3, 2d3 / 3 of the rear wind blade 122b is located in the flow guide ring 13. The vibration frequencies of the d3 / 3 part and the 2d3 / 3 part are different. However, since the d3 / 3 part already occupies a relatively large part of the rear wind blade 122b, although the 2d3 / 3 part occupies a larger part of the entire wind blade, this part is not sufficient to influence the vibration frequency of the d3 / 3 part. After the two are connected together, the vibration frequency depends on the d3 / 3 part, resulting in lower noise.

[0100] After d3 reaches 4d3 / 3, it is found that the noise reduction amplitude is relatively small. Continuing to extend the rear wind blade 122b into the air outlet duct 11 is not meaningful and will instead cause the air outlet duct 11 to be longer, increasing the manufacturing cost.

[0101] In view of this, it is better for d2 to be between d3 / 3 and 4d3 / 3.

[0102] Please refer to Figures 1 to 8, the present invention also provides an air conditioner indoor unit equipped with the above axial flow fan assembly. The indoor unit has a housing 21, and the housing 21 has a front panel 21a and a back panel 21b. The front panel 21a has an air outlet, and an air outlet frame is installed at the air outlet. The back panel 21b has an air inlet, and an air inlet grille is installed at the air inlet. A filter screen is arranged inside the air inlet grille. The heat exchanger 30 is installed inside the housing 21 and is located between the air inlet and the air outlet. Usually, the heat exchanger 30 can be installed on the back panel 21b or on the side panel. Of course, other installation methods are not excluded. The axial flow fan assembly is installed at the air outlet. When the air conditioner indoor unit performs the refrigeration function, the axial flow fan assembly operates, and a negative pressure is formed behind the axial flow fan assembly. Under the action of this negative pressure, external air passes through the heat exchanger 30 along the air inlet and is blown forward by the axial flow fan assembly towards the air conditioner indoor unit.

[0103] Please refer to Figure 8 , on the basis of the above embodiment, in order to reduce the noise during air conditioner operation, the distance between the rear end of the air guide ring and the heat exchanger 30 is d4, and 20mm ≤ d4 ≤ 120mm.

[0104] Table 4

[0105]

[0106] For the flared air guide ring 13, the larger d4 is, the lower the noise of the axial flow fan assembly at the same air volume. When d4 is greater than 120mm, the noise at the same air volume is basically unchanged. From the perspective of noise, the optimal value of d4 is 60mm. However, when d4 is too large, it will affect the thickness of the whole machine, and when d4 is greater than 80mm, the reduction amplitude of the noise at the same air volume decreases. Therefore, generally speaking, d4 is preferably between 60mm and 80mm.

[0107] The above embodiment is for a single bipolar axial flow fan (opposed-rotation fan).

[0108] In addition, through testing, when there is not only a single bipolar axial flow fan (opposed-rotation fan, named the first fan here) in the air conditioner, but also other fans (named the second fan), such as axial flow, cross-flow or centrifugal fans, the optimal value of d4 changes. Of course, the first fan and the second fan can both be set in the air conditioner indoor unit or both be set in the air conditioner outdoor unit.

[0109] To test the relationship between the noise generated by two or more fans and d4, the experiment is as follows (taking the indoor unit as an example):

[0110] Table 5

[0111]

[0112]

[0113] As can be seen from Table 5, when d4 is between 60 mm and 80 mm, the noise of the air conditioner indoor unit is relatively high. On the contrary, when d4 is between 30 mm and 40 mm, the noise of the air conditioner indoor unit is at the lowest level. Especially when d4 = 30 mm, the noise value is at the lowest state. The measuring method for d4 is as follows: ①. Take the fin of the heat exchanger closest to the guide ring and make a first plane parallel to the trailing edge of the rear fan (i.e., the plane formed when the rear fan rotates); ②. Take a point at the trailing edge of each blade of the rear fan and measure the distance between this point and the above-mentioned first plane respectively; ③. Average the above-mentioned multiple measured distance values to obtain the d4 value.

[0114] The above are only the preferred embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent structural transformation made under the inventive concept of the present invention by using the content of the specification and drawings of the present invention, or directly / indirectly applied in other related technical fields, is included in the patent protection scope of the present invention.

Claims

1. An axial flow fan assembly, comprising an air outlet cylinder and at least one blade mounted on the air outlet cylinder, the air outlet cylinder having a front port and a rear port, characterized in that, The axial flow fan assembly further includes: A guide vane ring, which is installed at the rear port of the air outlet cylinder, and the guide vane ring is flared backward. The diameter of the air outlet cylinder satisfies 250mm ≤ d0 ≤ 450mm, the axial width of the guide vane ring is m, 20mm ≤ m ≤ 80mm, and the radial distance between the rear end of the guide vane ring and the rear end of the air outlet cylinder is d1, 10mm ≤ d1 ≤ 50mm. The air outlet cylinder is only connected with a flared guide vane ring at its rear port; the air flow flows from the guide vane ring into the air outlet cylinder. The number of fan blades in the air outlet cylinder is two, and the two fan blades are a front fan blade and a rear fan blade. The front fan blade and the rear fan blade are arranged at intervals along the axis of the air outlet cylinder. The rotation direction of the front fan blade when blowing the air flow towards the front port is opposite to the rotation direction of the rear fan blade when blowing the air flow towards the front port. At least part of the rear fan blade is located inside the air outlet cylinder. The maximum axial distance between the leading edge of the rear fan blade and the rear port of the air outlet cylinder is d2, and the blade height of the rear fan blade is d3, where d3 / 3 ≤ d2 ≤ 4d3 / 3.

2. The axial flow fan assembly according to claim 1, characterized in that, 300mm ≤ d0 ≤ 400mm.

3. The axial flow fan assembly according to claim 1, wherein, 30mm ≤ m ≤ 60mm.

4. The axial flow fan assembly according to claim 1, wherein 30mm ≤ d1 ≤ 40mm.

5. The axial flow fan assembly according to claim 1, wherein, The inner wall surface of the guide vane ring is arranged as an arc surface convex outward backward.

6. The axial flow fan assembly according to claim 5, characterized in that, The inner wall surface of the guide vane ring is tangent to the inner wall surface of the air outlet cylinder.

7. The axial flow fan assembly according to claim 5, wherein, The curvature of the inner wall surface of the guide vane ring gradually decreases backward.

8. The axial flow fan assembly according to claim 5, characterized in that, The line segment of the inner wall surface of the guide vane ring intercepted by a plane parallel to the axis of the guide vane ring includes a plurality of arc segments arranged backward, and the plurality of arc segments are connected in sequence.

9. The axial flow fan assembly according to claim 1, characterized in that, The line segment of the inner wall surface of the guide vane ring intercepted by a plane parallel to the axis of the guide vane ring includes a plurality of arc segments and straight line segments arranged backward. Among them, the arc segments are arranged as arc surfaces convex outward backward, the arc segments are connected to the rear end of the air outlet cylinder, and the arc segments and the straight line segments are arranged alternately.

10. An air conditioner, characterized in that, Including the axial flow fan assembly according to any one of claims 1 to 9, the air conditioner includes an air conditioner indoor unit and an air conditioner outdoor unit. The axial flow fan assembly is placed inside the air conditioner indoor unit, and the air conditioner indoor unit is a floor-mounted air conditioner indoor unit or a ceiling-mounted air conditioner or a wall-mounted air conditioner indoor unit; and / or, The axial flow fan assembly is placed inside the air conditioner outdoor unit.

11. The air conditioner according to claim 10, wherein, The air conditioner indoor unit includes a housing and a heat exchanger. The housing has an air inlet and an air outlet. The heat exchanger is arranged corresponding to the air inlet. The axial flow fan assembly is installed between the heat exchanger and the air outlet. The distance between the rear fan blade and the heat exchanger is d4, 30mm ≤ d4 ≤ 120mm.

12. The air conditioner according to claim 11, characterized in that, 60mm ≤ d4 ≤ 80mm.

13. The air conditioner according to claim 11, characterized in that, The axial flow fan assembly is a first fan, and a second fan is further arranged inside the air conditioner. Both the first fan and the second fan are arranged in the air conditioner indoor unit, 30mm ≤ d4 ≤ 40mm; or, Both the first fan and the second fan are arranged in the air conditioner outdoor unit, 30mm ≤ d4 ≤ 40mm.

14. The air conditioner according to claim 13, characterized in that, The second fan is an axial flow fan or a centrifugal fan or a cross-flow fan.

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