Noise reduction type cross-flow wind wheel and air conditioner with same

Abstract

The utility model provides a noise reduction type cross-flow wind wheel and air conditioner with the same, the cross-flow wind wheel comprises at least one wind wheel section, the wind wheel section comprises a partition plate and a plurality of blades arranged along the circumferential direction of the partition plate, the suction surface of each blade is provided with a first arc section, a second arc section and a third arc section which are connected in sequence; the pressure surface of each blade is provided with a fourth arc section, a fifth arc section and a sixth arc section which are connected in sequence; the arc length of the first arc section is S1, the arc length of the second arc section is S2, and the arc length of the third arc section is S3; the arc length of the fourth arc section is S4, the arc length of the fifth arc section is S5, and the arc length of the sixth arc section is S6; wherein S1 / S4 is more than 0.3 and less than 0.4, S2 / S5 is more than 2.8 and less than 2.9, and S3 / S6 is more than 0.2 and less than 0.3. Based on the technical scheme provided by the utility model, the influence of the arc length of each section of the suction surface and the pressure surface of the blade on noise and air volume is correlated, and the aerodynamic performance and the noise characteristic of the blade are jointly determined. The working noise of the cross-flow wind wheel is reduced through reasonable arc lengths of all the sections, and meanwhile the air volume is not affected.

Description

Technical Field

[0001] The utility model relates to the technical field of air conditioning, in particular to a noise reduction type crossflow fan wheel and an air conditioner having the same. Background Art

[0002] The whistling sound of the wall-mounted unit is caused by the periodic impact of the fan on the volute tongue, which generates sound waves and radiates outward. The fan has N blades, for example 35, and the airflow passing between each blade will impact the volute tongue, thereby generating sound waves. After superposition, the amplitude increases and is transmitted to the human ear as a sharp whistle, similar to the sound of whistling, which greatly affects the ear perception.

[0003] Means to reduce the whistling sound include non-periodic circumferential distribution of blades, certain angle distribution between different sections of the fan, and adding special structures to the volute tongue.

[0004] The existing fans all have non-periodic circumferential distribution designs of blades, but the whistling sound is still obvious. Utility Model Content

[0005] One purpose of the utility model is to reduce the noise of the crossflow impeller.

[0006] A further object of the utility model is to ensure that the air volume of the crossflow impeller remains unchanged.

[0007] In particular, the utility model provides a noise reduction type crossflow wind wheel, comprising at least one wind wheel section, wherein the wind wheel section comprises a partition and a plurality of blades arranged along the circumference of the partition, and is characterized in that:

[0008] The suction surface of the blade comprises a first circular arc segment, a second circular arc segment and a third circular arc segment which are connected in sequence;

[0009] The pressure surface of the blade has a fourth arc segment, a fifth arc segment and a sixth arc segment which are connected in sequence;

[0010] The arc length of the first arc segment is S1, the arc length of the second arc segment is S2, and the arc length of the third arc segment is S3;

[0011] The arc length of the fourth arc segment is S4, the arc length of the fifth arc segment is S5, and the arc length of the sixth arc segment is S6; wherein

[0012] 0.3<S1 / S4<0.4, 2.8<S2 / S5<2.9, 0.2<S3 / S6<0.3.

[0013] Optionally, 1 mm < S1 < 2 mm; and / or

[0014] 9mm<S2<10mm; and / or

[0015] 2mm<S3<3mm; and / or

[0016] 3mm<S4<4mm; and / or

[0017] 3mm<S5<4mm; and / or

[0018] 8mm<S6<10mm.

[0019] Optionally, the radius of the first arc segment is r1, the radius of the second arc segment is r2, and the radius of the third arc segment is r3;

[0020] The radius of the fourth arc segment is r4, the radius of the fifth arc segment is r5, and the radius of the sixth arc segment is r6;

[0021] 0.3<r1 / r4<0.4, 0.8≤r2 / r5<0.9, 0.9<r3 / r6<1.

[0022] Optionally,

[0023] 7mm<r1<8mm; and / or

[0024] 12mm<r2<13mm; and / or

[0025] 9mm<r3<10mm; and / or

[0026] 19mm<r4<20mm; and / or

[0027] 15mm<r5<16mm; and / or

[0028] 9mm<r5<11mm.

[0029] Optionally, the chord length of the first arc segment is P1, the chord length of the second arc segment is P2, and the chord length of the third arc segment is P3;

[0030] The chord length of the fourth arc segment is P4, the chord length of the fifth arc segment is P5, and the chord length of the sixth arc segment is P6;

[0031] 0.3<P1 / P4<0.4, 2.7<P2 / P5<2.8, 0.4<P3 / P6<0.5.

[0032] Optionally, 1 mm < P1 < 2 mm; and / or

[0033] 9mm<P2<10mm; and / or

[0034] 2mm<P3<3mm; and / or

[0035] 3mm<P4<4mm; and / or

[0036] 3mm<P5<4mm; and / or

[0037] 5mm<P6<6mm.

[0038] Optionally, the leading edge diameter d3 of the blade is selected from any value between 0.5 mm and 1 mm; and / or

[0039] The trailing edge diameter d4 of the blade is selected from any value between 1 mm and 2 mm.

[0040] Optionally, the thickness of the thickest part of the blade is selected from any value between 1 mm and 2 mm.

[0041] Optionally, the number of the blades is an odd number, the number of the blades is Y, and 32<Y<38.

[0042] According to another aspect of the utility model, an air conditioner is provided, characterized in that it comprises a noise reduction type crossflow impeller as described in any one of the above items.

[0043] The noise reduction crossflow wind wheel proposed in the utility model includes at least one wind wheel section, and the wind wheel section includes a partition and a plurality of blades arranged along the circumference of the partition, wherein the suction surface of the blade has a first arc segment, a second arc segment and a third arc segment connected in sequence; the pressure surface of the blade has a fourth arc segment, a fifth arc segment and a sixth arc segment connected in sequence; the arc length of the first arc segment is S1, the arc length of the second arc segment is S2, and the arc length of the third arc segment is S3; the arc length of the fourth arc segment is S4, the arc length of the fifth arc segment is S5, and the arc length of the sixth arc segment is S6; wherein 0.3<S1 / S4<0.4, 2.8<S2 / S5<2.9, 0.2<S3 / S6<0.3. Based on the technical solution proposed in the utility model, the influence of the arc length of each section of the suction surface of the blade and the arc length of each section of the pressure surface on the noise and air volume is interrelated, and they jointly determine the aerodynamic performance and noise characteristics of the blade. By reasonably setting the arc lengths of each section of the suction surface and the arc lengths of each section of the pressure surface, the working noise of the crossflow impeller is reduced without affecting the air volume.

[0044] The above description is only an overview of the technical solution of the utility model. In order to more clearly understand the technical means of the utility model, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the utility model more obvious and easy to understand, the specific implementation methods of the utility model are listed below.

[0045] Based on the detailed description of the specific embodiments of the present invention in combination with the accompanying drawings below, those skilled in the art will become more aware of the above and other purposes, advantages and features of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Hereinafter, some specific embodiments of the present invention will be described in detail in an exemplary and non-limiting manner with reference to the accompanying drawings. The same reference numerals in the accompanying drawings indicate the same or similar components or parts. It should be understood by those skilled in the art that these drawings are not necessarily drawn to scale. In the accompanying drawings:

[0047] Hereinafter, some specific embodiments of the present invention will be described in detail in an exemplary and non-limiting manner with reference to the accompanying drawings. The same reference numerals in the accompanying drawings indicate the same or similar components or parts. It should be understood by those skilled in the art that these drawings are not necessarily drawn to scale. In the accompanying drawings:

[0048] Figure 1 is a first schematic diagram of a noise reduction crossflow impeller according to an embodiment of the utility model;

[0049] Figure 2 is a second schematic diagram of a noise reduction crossflow impeller according to an embodiment of the utility model;

[0050] Figure 3 This is a first schematic diagram of a noise reduction crossflow impeller after being disassembled according to an embodiment of the utility model;

[0051] Figure 4 is a second schematic diagram of a noise reduction crossflow impeller after being disassembled according to an embodiment of the utility model;

[0052] Figure 5 It is a structural schematic diagram of a wind wheel section according to an embodiment of the utility model;

[0053] Figure 6 is a top view of a wind wheel section according to an embodiment of the utility model;

[0054] Figure 7 This is a schematic diagram of the variation trend of the center angle between adjacent blades according to an embodiment of the utility model;

[0055] Figure 8 is a first schematic diagram of a noise reduction crossflow wind wheel blade according to an embodiment of the utility model;

[0056] Fig. 9 is a second schematic diagram of a noise reduction crossflow wind wheel blade according to an embodiment of the utility model;

[0057] Fig.10 It is a schematic structural block diagram of an air conditioner according to an embodiment of the utility model. DETAILED DESCRIPTION

[0058] Refer to the following Figures 1 to 10The crossflow impeller of the embodiment of the utility model and the air conditioner having the same are described in detail. The directions or positional relationships indicated by "front", "rear", "upper", "lower", "inner", "outer", etc. are based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the utility model.

[0059] The terms "first", "second", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first", "second", etc. may explicitly or implicitly include at least one of the features, that is, include one or more of the features. In the description of the present utility model, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined. When a feature "includes or contains" one or some of the features it covers, unless otherwise specifically described, this indicates that other features are not excluded and may further include other features.

[0060] In the description of the present embodiment, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0061] Unless otherwise defined, all terms (including technical terms and scientific terms) used in the description of the embodiments of the present invention have the same meanings as those commonly understood by ordinary technicians in the technical field to which the present application belongs.

[0062] The principle of unequal distance noise reduction is as follows:

[0063] Blade rotation angular velocity: ω = n × 2π;

[0064] The rotation time interval between adjacent blades:

[0065] The noise frequency generated between adjacent blades:

[0066] For an equidistant wind rotor, the spacing between adjacent blades is the same, and the noise frequency f i This harmonic coherence enhances the pulsation intensity at the fundamental frequency, which appears as a prominent peak in the spectrum.

[0067] For unequally spaced wind rotors, the spacing between adjacent blades is different, which will cause the equal-spaced fundamental frequency f 1 Weaken to a distribution frequency (f 2 ,f 3 ), thereby reducing the rotational noise and weakening the peak of the equidistant wind wheel at the fundamental frequency to a smaller distribution value in the frequency spectrum.

[0068] Figure 1 is a first schematic diagram of a crossflow wind wheel according to an embodiment of the utility model;

[0069] Figure 2 is a second schematic diagram of a crossflow wind wheel according to an embodiment of the utility model;

[0070] Figure 3 This is a first schematic diagram of a disassembled crossflow impeller according to an embodiment of the utility model;

[0071] Figure 4 is a second schematic diagram of a disassembled crossflow impeller according to an embodiment of the utility model;

[0072] Figure 5 It is a structural schematic diagram of a wind wheel section according to an embodiment of the utility model;

[0073] Figure 6 is a top view of a wind wheel section according to an embodiment of the utility model;

[0074] Figure 7 The figure is a schematic diagram of the variation trend of the center angle between adjacent blades according to an embodiment of the utility model.

[0075] See also Figure 1-7 As shown, the utility model proposes a crossflow wind wheel 1, which includes at least one wind wheel section 10, and the wind wheel section 10 includes a partition 12 and a plurality of blades 11 arranged circumferentially along the partition 12, wherein the plurality of blades 11 are unequally distributed along the circumferential direction, and the central angles between any two adjacent blades 11 are divided into m groups in a clockwise direction, wherein the central angle data of the T-1th group changes with a first change trend, the central angle data of the Tth group changes with a second change trend, and the central angle data of the T+1th group changes with a third change trend, wherein at least one of the first change trend, the second change trend and the third change trend is an oscillating increase or an oscillating decrease.

[0076] Among them, the partition 12 is annular, and the blades 11 are arranged along the circumference of the partition 12 and are arranged at unequal intervals, that is, any two adjacent blades 11 among all the blades 11 can form a central angle α, and these central angles α are not completely equal, and at least one central angle α is different from the other central angles α.

[0077] Preferably, the degree of each central angle α is not equal, or several consecutive central angles α are equal, and the remaining central angles α are not equal. The central angle α is determined by connecting a line from a point on the side of the blade 11 close to the axis of the crossflow wind wheel 1 to the center of the circle on which it is located, and the center angle α is between the two connecting lines. When determining the central angle α, it is not necessary to select a specific point for determination, as long as each blade 11 is connected from the same position to the center of the circle on which it is located.

[0078] In this embodiment, a new distribution is designed based on the circumferential non-periodic distribution of the blades 11, so that there are differences in the impact intensity and phase of each blade 11 on the volute tongue when passing through the volute tongue, causing mutual interference between harmonics, and the frequency spectrum characteristics are discrete, thereby reducing the working noise of the crossflow impeller 1.

[0079]

[0080]

[0081] Table 1 Center Angle Table

[0082] Figure 7 The change trend of the central angle α shown is obtained by plotting the central angle α data shown in Table 1 above.

[0083] See also Figure 7 As shown, in some preferred or alternative embodiments according to the utility model, the central angle α is divided into groups m≥6, preferably 6 groups, wherein the central angle α data of the second group changes in an oscillating downward trend, the central angle α data of the third group changes in an oscillating upward trend, and the central angle α data of the fourth group changes in an oscillating downward trend.

[0084] Among them, the three adjacent groups of central angle α data change in an oscillating upward or oscillating downward trend, which further makes the impact intensity and phase of each blade 11 on the volute tongue different when passing through the volute tongue, causing mutual interference between harmonics, and the frequency spectrum characteristics are discrete, thereby achieving the effect of further reducing the working noise intensity of the blade 11.

[0085] In some preferred or alternative embodiments of the present invention, 8°<α<13°.

[0086] During the operation of the crossflow impeller 1, the noise generated includes not only the pulsating pressure on the surface of the blades 11, but also the pulsating pressure on the surface of the stationary volute wall and the rear volute wall. The blades 11 are arranged in an unequal spacing structure, resulting in differences in the impact intensity and phase of each blade 11 on the volute tongue when passing through the volute tongue. Its frequency spectrum characteristics are discrete, and the noises between different frequencies interfere with each other, making resonance less likely to occur, thereby effectively reducing the noise intensity.

[0087] In some preferred or alternative embodiments of the present invention, each central angle α is substituted into the following formula (1):

[0088]

[0089] Among them, X i is the angle of the i-th central angle α, and n is the number of central angles α;

[0090] Calculated

[0091] In a specific embodiment, according to the data in Table 1 above,

[0092] In some preferred or alternative embodiments of the present invention, the central angles are arranged in order from small to large or from large to small, and the specific central angle q is determined according to the following formula (2):

[0093]

[0094] Where n is the number of central angles;

[0095] 10°<q<11°.

[0096] In a specific embodiment, according to the data in Table 1 above, the degree of the specific central angle q is 10.2031°.

[0097] In some preferred or alternative embodiments of the present invention, the degree of each center angle is substituted into the following formula (3):

[0098]

[0099] Where n is the number of central angles, X i is the angle of the center of the ith circle, is the average value of the center angle;

[0100] Calculation shows that 1<D(X)<2.

[0101] In a specific embodiment, according to the data in Table 1 above, D(X) is 1.4174.

[0102] In some preferred or alternative embodiments according to the present invention, the number of blades 11 is an odd number.

[0103] Among them, the number of blades 11 is an odd number, the number of blades 11 is Y, 32<Y<38, preferably 33, 35 or 37 blades. The odd number of blades 11 can make the frequency of vibration generated during the rotational air supply more coprime with the frequency of other vibrations in the surrounding environment, reduce the resonance between the blades 11 and the surrounding environment, and reduce the rotation noise of the crossflow impeller 1.

[0104] In some preferred or alternative embodiments of the present invention, a plurality of wind wheel segments 10 are sequentially arranged along the axis direction of the crossflow wind wheel, wherein

[0105] The blades 11 on adjacent wind wheel sections 10 are arranged in one-to-one correspondence; or

[0106] The blades 11 on adjacent wind wheel sections 10 are arranged staggered; or

[0107] The blades 11 on some of the wind rotor segments 10 among the plurality of wind rotor segments 10 are arranged in a one-to-one correspondence, and the blades 11 on the remaining wind rotor segments 10 are arranged in a staggered manner.

[0108] The blades 11 on two adjacent wind rotor sections 10 are arranged in a one-to-one correspondence, that is, after the crossflow wind rotor 1 is installed, there will be no misalignment of the blades 11 on its surface. In another preferred alternative embodiment, the blades 11 on adjacent wind rotor sections 10 are arranged staggered, or the blades 11 on some of the wind rotor sections 10 in the plurality of wind rotor sections 10 are arranged in a one-to-one correspondence, and the blades 11 on the remaining wind rotor sections 10 are arranged staggered, which can further reduce discrete frequency noise.

[0109] In some preferred or alternative embodiments of the present invention, at least one wind wheel section 10 is located between the oppositely arranged driven shaft end cover 30 and the driving end cover 20, wherein the driven shaft end cover 30 is provided with a rotating shaft 50, and the driving end cover 20 is provided with a motor shaft sleeve 40.

[0110] Among them, a plurality of wind wheel segments 10 are arranged between the driven shaft end cover 30 and the driving end cover 20 and are fixedly arranged in sequence along the axial direction of the crossflow wind wheel 1. The number of wind wheel segments 10 is selected from any value between 9 and 13 segments, preferably 11 segments. Among them, a rotating shaft 50 is arranged on the driven shaft end cover 30, and the rotating shaft 50 rotates together with the wind wheel segment 10 under the drive of the motor. In addition, the rotating shaft 50 plays a supporting role and is also used to install the crossflow wind wheel 1 as a whole in the housing of the air conditioning and ventilation system. A plurality of ribs 60 are also arranged on the inner side of the driven shaft end cover 30, preferably six, and the ribs 60 are triangular plate structures with equal thickness, and are in the shape of a hexagram as a whole. One end of the plurality of ribs 60 intersects on the axis of the driven shaft end cover 30. The driving end cover 20 is located on the motor side, and a motor sleeve 40 is arranged on the outer wall of the driving end cover 20. The motor sleeve 40 is connected to the motor to transmit the power of the motor to the wind wheel segment 10 and drive the wind wheel segment 10 to rotate. Both the driving end cover 20 and the driven shaft end cover 30 can block the airflow inside the noise reducing wind wheel 1 from moving along the axial direction of the noise reducing wind wheel 1 .

[0111] In addition, the diameter of the steel shaft disc is selected from any value between 2 mm and 4 mm, preferably 3 mm.

[0112] In some preferred or alternative embodiments of the present invention, the inclination angle of the blade 11 is θ, the height of the blade 11 is h, and the number of blades 11 on the partition 12 is Y, wherein:

[0113]

[0114] Among them, k1 is a constant, 2<k1<12.

[0115] like Figure 6 As shown, the top and bottom ends of the blade 11 close to the axis of the crossflow impeller 1 are connected to the center of the circle on which they are located, and the distance between the two connecting lines is the inclination angle, and h is the vertical height h of the blade 11, which is also the distance between adjacent partitions 12.

[0116] The change in the inclination angle will change the flow path and speed of the air between the blades 11, thereby affecting the stability of the airflow. Unstable airflow is prone to turbulence and eddy currents. A moderate inclination angle of the blades 11 helps reduce the instability of the airflow, thereby reducing noise. The number of blades 11 directly affects the air supply and wind pressure of the fan. At the same time, the number of blades 11 also determines the number of times the airflow is divided and reorganized inside the fan, which affects the generation of noise. Under the same fan size and speed, the more blades 11 there are, the less air each blade 11 pushes, which helps reduce the noise generated by a single blade 11. However, an increase in the number of blades 11 will also increase the overall noise level of the fan, because more blades 11 mean more airflow disturbances and collisions. Therefore, it is necessary to find a balance between the number of blades 11 and the noise level. The height h of the blades 11, that is, the distance between adjacent partitions 12, mainly affects the flow space of the airflow inside the fan. A smaller distance between the partitions 12 may restrict the flow of air, causing turbulence and eddies between the partitions 12; while a larger distance between the partitions 12 may cause the airflow to be too dispersed, reducing the air supply efficiency of the fan. Reasonable setting of the distance between the partitions is crucial to reducing fan noise. Too small a distance between the partitions will increase the noise generation, because the airflow is more likely to generate turbulence and eddies in a confined space; while too large a distance between the partitions 12 may reduce the air supply efficiency of the fan, and at the same time fail to effectively reduce noise.

[0117] When the number of blades 11 is small, especially when the number of blades 11 is less than 10, the air volume of the fan increases significantly with the increase in the number of blades 11, and this relationship is approximately linear. When the number of blades 11 increases further, between 10 and 39, the growth trend of the air volume gradually slows down, but still keeps growing. However, when the number of blades 11 exceeds 39, the air volume may decrease with the increase in the number of blades 11. This is because too many blades 11 will increase the resistance to air flow, resulting in a decrease in air volume. Within the optional size range, an increase in the height h of the blade 11 usually leads to an increase in air volume. This is because a higher blade 11 can more effectively promote air flow, thereby generating a larger air volume. However, if the height h of the blade 11 is too high, it may cause unstable air flow and increased wind resistance, which in turn affects the output of air volume. The inclination angle of the blade 11 is one of the key factors affecting the air volume of the fan. When the inclination angle of the blade 11 is small, the air flow generated is mainly formed by the air driven by the rotation of the fan blade. At this time, the air flow speed is slow and the air volume is small. As the inclination angle of the blade 11 increases, the air is forced to accelerate when passing through the fan blade, forming a stronger airflow, thereby increasing the air volume. However, too large an inclination angle may also cause wind direction changes or backflow, affecting fan performance.

[0118] The influence of the height h of the blade 11, the inclination angle of the blade 11 and the number of the blades 11 on the noise and air volume are interrelated, and they jointly determine the aerodynamic performance and noise characteristics of the blade 11. This embodiment effectively reduces the working noise of the crossflow impeller 1 while ensuring that the air volume of the blades 11 remains unchanged by reasonably setting the inclination angle of the blade 11, the number of the blades 11 and the distance between the partitions 12.

[0119] In some preferred or alternative embodiments according to the present invention, 6°<θ<7°.

[0120] In some preferred or alternative embodiments of the present invention, 55 mm<h<65 mm.

[0121] In some preferred or alternative embodiments of the present invention, at least one wind wheel section 10 is located between the driven shaft end cover 30 and the driving end cover 20 which are arranged opposite to each other, wherein:

[0122] The height h of the blade 11 of the wind wheel section 10 closest to the driving end cover 20 is h1, 63mm

[0123] The height h of the blades 11 of the remaining wind wheel segments 10 is h2, and 55 mm<h2<57 mm.

[0124] In a specific embodiment, the inclination angle θ of the blade 11 is 6.72°, the height h of the blade 11 is 56 mm, the number Y of the blades 11 is 35, and k1 is 8.2. ​

[0125] In another specific embodiment, the inclination angle θ of the blade 11 is 6.72°, the height h of the blade 11 is 64 mm, the number Y of the blades 11 is 35, and k1 is 2.8.

[0126] In some preferred or alternative embodiments of the present invention, the inscribed circle diameter of all blades 11 on the wind wheel section 10 is d1, the circumscribed circle diameter is d2, and the chord length is L1, wherein:

[0127]

[0128] Among them, k2 is a constant, 12<k2<13.

[0129] Figure 8 FIG. 1 is a first schematic diagram of a crossflow wind wheel blade 11 according to an embodiment of the present invention. Figure 6 , 8 As shown, the inscribed circle diameter d1 is the diameter of the circle formed by connecting all the blades 11 at a point close to the central axis of the crossflow wind wheel 1; the circumscribed circle diameter d2 is the diameter of the circle formed by connecting all the blades 11 at a point far from the central axis of the crossflow wind wheel 1; the chord length L1 of the blade 11 is the distance between the center of the leading edge and the center of the trailing edge of the blade 11.

[0130] Among them, the size of the inscribed circle diameter d1 will affect the air flow velocity and pressure distribution inside the wind wheel 1. A smaller inscribed circle diameter d1 may lead to a narrow air flow channel, increase air flow turbulence and eddy currents, and thus generate more aerodynamic noise. Aerodynamic noise is one of the main components of crossflow fan noise, so changes in the inscribed circle diameter d1 will directly affect the noise level. An increase in the circumscribed circle diameter d2 will increase the area of ​​the wind wheel 1, thereby theoretically increasing the air volume and wind pressure. However, an excessively large circumscribed circle diameter d2 may also result in a reduction in the gap between the wind wheel 1 and surrounding components (such as the volute), increasing noise. Changes in the chord length L1 of the blade 11 will directly affect the shape and area of ​​the blade 11, and thus affect the aerodynamic performance of the wind wheel 1. A longer chord length L1 may increase the stiffness of the blade 11, reduce vibration and noise; but an excessively long chord length L1 may also increase the weight of the blade 11, increasing the load and noise of the motor. Changes in the chord length L1 will also affect the frequency characteristics of the noise. Generally speaking, a longer chord length L1 may shift the frequency of the noise toward a low frequency, while a shorter chord length L1 may shift the frequency of the noise toward a high frequency.

[0131] If the inscribed circle diameter d1 is too small, the structural strength of the blade 11 may be insufficient, affecting the reliability and life of the fan; if it is too large, it may increase the resistance of the blade 11 and reduce the air volume. The circumscribed circle diameter d2 directly affects the swept area of ​​the fan, that is, the area that the blade 11 can cover when it rotates. The larger the swept area, the more air can be driven in theory, thereby increasing the air volume. However, the increase in the circumscribed circle diameter d2 will also bring greater resistance and higher energy consumption. Therefore, it is necessary to weigh the relationship between air volume, resistance and energy consumption during design. The increase in the chord length L1 can improve the uniformity of the load distribution of the blade 11 and reduce the drag coefficient of the blade 11, thereby increasing the air volume to a certain extent. This is because a longer chord length L1 can more effectively utilize wind energy and improve the conversion efficiency of wind energy. However, an excessively long chord length L1 will also increase the cost and weight of the blade 11, reduce the speed and power of the fan, and thus may affect the air volume. Therefore, when selecting the chord length L1, it is necessary to weigh it according to the specific use environment and needs.

[0132] The influence of the inscribed circle diameter d1, the circumscribed circle diameter d2, the chord length L1 of the blade 11 and the number Y of the blades 11 on the noise and air volume are interrelated, and they jointly determine the aerodynamic performance and noise characteristics of the blade 11. In this embodiment, by reasonably setting the inscribed circle diameter d1, the circumscribed circle diameter d2, the number Y of the blades 11 and the chord length L1 of the blades 11, the working noise of the crossflow wind wheel 1 is further reduced while ensuring that the air volume of the blades 11 remains unchanged.

[0133] In some preferred or alternative embodiments of the present invention, 71 mm<d1<73 mm.

[0134] In some preferred or alternative embodiments of the present invention, 101 mm<d2<103 mm.

[0135] In some preferred or alternative embodiments of the present invention, 12 mm<L<13 mm.

[0136] In a specific embodiment, the inscribed circle diameter d1 is 72 mm, the circumscribed circle diameter d2 is 102 mm, the number Y of blades 11 is 35, the chord length L1 of the blade 11 is 12.363 mm, and k2 is 12.34.

[0137] See also Figure 5 As shown, in some preferred or alternative embodiments according to the present invention, the blade 11 has a relative suction surface and a pressure surface, wherein:

[0138] The suction surface of the blade 11 comprises a first arc segment a, a second arc segment b and a third arc segment c which are connected in sequence;

[0139] The pressure surface of the blade 11 has a third arc segment c, a fourth arc segment d and a fifth arc segment e which are connected in sequence;

[0140] The arc length of the first arc segment a is S1, the arc length of the second arc segment b is S2, and the arc length of the third arc segment c is S3;

[0141] The arc length of the fourth arc segment d is S4, the arc length of the fifth arc segment e is S5, and the arc length of the sixth arc segment f is S6; wherein,

[0142] 0.3<S1 / S4<0.4, 2.8<S2 / S5<2.9, 0.2<S3 / S6<0.3.

[0143] See also Figure 6 As shown, the suction surface of the blade 11 is a convex arc surface of the blade 11, the pressure surface of the blade 11 is a concave arc surface of the blade 11, the first arc segment a, the second arc segment b and the third arc segment c are arranged in sequence from the leading edge to the trailing edge of the blade 11 and are arc transitions, and the fourth arc segment d, the fifth arc segment e and the sixth arc segment f are arranged in sequence from the leading edge to the trailing edge of the blade 11 and are arc transitions.

[0144] The suction surface of the blade 11 is the side of the blade 11 where the airflow velocity is higher and the pressure is lower, and is usually located on the leeward side of the blade 11. On this side, the airflow is guided by the shape of the blade 11, resulting in a specific flow pattern and pressure distribution, which have an important impact on the generation and propagation of noise. The arc length of each section of the suction surface of the blade 11 will directly affect the flow path and velocity distribution of the airflow. Changes in arc length may cause separation of the airflow on the surface of the blade 11, the generation of vortices or other unsteady flow phenomena, all of which will increase the generation of noise. In addition, changes in arc length will also affect the pressure distribution on the suction surface of the blade 11. Different arc lengths may cause changes in the pressure gradient, thereby affecting the stability of the airflow and generating noise.

[0145] The pressure surface of the blade 11 is the side of the blade 11 where the airflow velocity is lower and the pressure is higher, and is usually located on the windward side of the blade 11. On this side, the airflow is blocked and compressed by the blade 11, resulting in a specific flow pattern and pressure distribution, which have an important impact on the generation and propagation of noise. The arc length of each section of the pressure surface of the blade 11 will directly affect the flow stability of the airflow. Changes in arc length may cause the flow of airflow on the surface of the blade 11 to become unstable, generating turbulence or eddies, thereby increasing the generation of noise. In addition, changes in arc length will also affect the pressure distribution on the pressure surface of the blade 11. Different arc lengths may cause changes in the pressure gradient, thereby affecting the stability of the airflow and the generation of noise.

[0146] The design of the arc length of the suction surface directly affects the attachment of the airflow to the surface of the blade 11. A longer arc length of the suction surface helps the airflow to remain attached to the blade 11 for a longer time, reducing premature separation and the formation of vortices. This can improve the flow efficiency of the airflow, thereby increasing the air volume. On the contrary, if the arc length of the suction surface is too short, the airflow may quickly separate near the leading edge of the blade 11, forming vortices and turbulence, increasing resistance and reducing air volume. Changes in the arc length of the suction surface will affect the lift coefficient of the blade 11. A reasonable arc length design can optimize the lift coefficient, allowing the blade 11 to capture and push air more effectively during rotation, thereby increasing the air volume. By reducing the formation of vortices and turbulence, a longer arc length of the suction surface can improve the aerodynamic efficiency of the blade 11, reduce energy losses, and further increase the air volume.

[0147] The change in the arc length of the blade pressure surface will also affect the drag coefficient of the blade 11. Although the pressure surface mainly bears pressure, an excessively long arc length may increase the resistance and weight of the blade 11, which will have an adverse effect on the increase in air volume. Therefore, it is necessary to find a balance point so that the arc length can maintain low resistance while ensuring smooth flow of airflow.

[0148] The influence of the arc lengths of the suction surface and the pressure surface of the blade 11 on the noise and air volume is interrelated, and they jointly determine the aerodynamic performance and noise characteristics of the blade 11. This embodiment further reduces the working noise of the crossflow impeller 1 without affecting the air volume by reasonably setting the arc lengths of the suction surface and the pressure surface.

[0149] In some preferred or alternative embodiments according to the present invention,

[0150] 1mm<S1<2mm; and / or

[0151] 9mm<S2<10mm; and / or

[0152] 2mm<S3<3mm; and / or

[0153] 3mm<S4<4mm; and / or

[0154] 3mm<S5<4mm; and / or

[0155] 8mm<S6<10mm.

[0156] In a specific embodiment, S1 is 1.2756 mm, S2 is 9.8703 mm, S3 is 2.4990 mm, S4 is 3.3923 mm, S5 is 3.4454 mm, S6 is 8.9609 mm, S1 / S4=0.38, S2 / S5=2.86, S3 / S6=0.28.

[0157] In some preferred or alternative embodiments of the present invention, the radius of the first arc segment a is r1, the radius of the second arc segment b is r2, and the radius of the third arc segment c is r3;

[0158] The radius of the fourth arc segment d is r4, the radius of the fifth arc segment e is r5, and the radius of the sixth arc segment f is r6;

[0159] 0.3<r1 / r4<0.4, 0.8≤r2 / r5<0.9, 0.9<r3 / r6<1.

[0160] The change in the radius of each section of the suction surface of the blade 11 will directly affect the flow path and velocity distribution of the airflow. As the radius increases, the airflow velocity may increase, causing the flow to become more complex, generating unstable flow phenomena such as eddies and turbulence, thereby increasing the generation of noise. In addition, the change in radius will also affect the pressure distribution on the suction surface of the blade 11. At a larger radius, due to the increase in airflow velocity, the pressure may decrease, forming a low-pressure area, which may cause the airflow to separate or reattach in this area, thereby generating noise. In addition, the noise generated by the suction surface of the blade 11 will radiate and propagate outward in the form of sound waves. The intensity and frequency of noise sources at different radii may be different, resulting in superposition and interference of sound waves during propagation, further affecting the distribution and intensity of the noise.

[0161] The change in the radius of each section of the pressure surface of the blade 11 will directly affect the pressure distribution. As the radius increases, the compression effect of the airflow on the blade 11 increases, and the pressure gradient may change, which in turn affects the stability of the airflow and the generation of noise. In addition, the change in radius will also affect the flow characteristics of the airflow. At a larger radius, the airflow velocity may increase, causing the flow to become more complex, and may produce unstable flow phenomena such as eddies and turbulence, thereby increasing noise. In addition, the noise generated by the pressure surface of the blade 11 will also radiate and propagate outward in the form of sound waves. The intensity and frequency of noise sources at different radii may be different, resulting in superposition and interference of sound waves during propagation, further affecting the distribution and intensity of the noise.

[0162] The change in the radius of the suction surface of the blade 11 will directly affect the attachment length of the airflow on the surface of the blade 11. A larger suction surface radius may allow the airflow to remain attached over a longer distance, reduce the generation of vortices and turbulence, and thus improve the flow efficiency of the airflow. The change in the radius of the suction surface will also affect the separation point of the airflow. A smaller radius may cause the airflow to separate prematurely, forming vortices and turbulence, reducing aerodynamic efficiency and reducing air volume. A proper radius design can delay the separation of the airflow, allowing more air to be effectively captured and pushed.

[0163] The change in the radius of the pressure surface of the blade 11 will directly affect the pressure distribution on the surface of the blade 11. As the radius increases, the pressure gradient on the pressure surface may change, thereby affecting the flow characteristics of the airflow. Appropriate pressure surface radius design helps to maintain the stability of the airflow and reduce the generation of vortices and turbulence. This helps to improve the flow efficiency of the airflow, thereby increasing the wind volume. Although the pressure surface mainly bears pressure, changes in its radius will still have a certain impact on the lift. A reasonable pressure surface radius design can optimize the lift coefficient, allowing the blade 11 to capture and push air more effectively during rotation. An excessively large pressure surface radius may increase the resistance of the blade 11, resulting in increased energy loss. Therefore, it is necessary to find a balance between lift and resistance during the design process to ensure that the wind volume is maximized.

[0164] The influence of the radii of the suction surface and the pressure surface of the blade 11 on the noise and air volume is interrelated, and they jointly determine the aerodynamic performance and noise characteristics of the blade 11. This embodiment further reduces the working noise of the crossflow impeller 1 without affecting the air volume by reasonably setting the radii of the suction surface and the pressure surface.

[0165] In some preferred or alternative embodiments according to the present invention,

[0166] 7mm<r1<8mm; and / or

[0167] 12mm<r2<13mm; and / or

[0168] 9mm<r3<10mm; and / or

[0169] 19mm<r4<20mm; and / or

[0170] 15mm<r5<16mm; and / or

[0171] 9mm<r6<11mm.

[0172] In a specific embodiment, r1 is 7.2 mm, r2 is 12.2 mm, r3 is 9.1 mm, r4 is 19.7 mm, r5 is 15.2 mm, r6 is 10.0 mm, r1 / r4=0.37, r2 / r5=0.8, r3 / r6=0.91.

[0173] In some preferred or alternative embodiments of the present invention, the chord length of the first arc segment a is P1, the chord length of the second arc segment b is P2, and the chord length of the third arc segment c is P3;

[0174] The chord length of the fourth arc segment d is P4, the chord length of the fifth arc segment e is P5, and the chord length of the sixth arc segment f is P6;

[0175] 0.3<P1 / P4<0.4, 2.7<P2 / P5<2.8, 0.4<P3 / P6<0.5.

[0176] In some preferred or alternative embodiments according to the present invention,

[0177] 1mm<P1<2mm; and / or

[0178] 9mm<P2<10mm; and / or

[0179] 2mm<P3<3mm; and / or

[0180] 3mm<P4<4mm; and / or

[0181] 3mm<P5<4mm; and / or

[0182] 5mm<P6<6mm.

[0183] In a specific embodiment, P1 is 1.2739 mm, P2 is 9.6042 mm, P3 is 2.4911 mm, P4 is 3.3881 mm, P5 is 3.4381 mm, P6 is 5.4466 mm, P1 / P4=0.38, P2 / P5=2.79, P3 / P6=0.46.

[0184] In some preferred or alternative embodiments according to the present invention,

[0185] The leading edge diameter d3 of the blade 11 is selected from any value between 0.5 mm and 1 mm; and / or

[0186] The trailing edge diameter d4 of the blade 11 is selected from any value between 1 mm and 2 mm.

[0187] In a specific embodiment, the diameter d3 of the leading edge of the blade 11 is 0.8 mm, and the diameter d4 of the trailing edge of the blade 11 is 1.5 mm.

[0188] The leading edge of the blade 11 is the first part of the blade 11 that the air contacts, and changes in its diameter will directly affect the pattern and speed of air flow. A larger leading edge diameter may lead to stronger air disturbances and vortices, thereby increasing aerodynamic noise. In addition, changes in the leading edge diameter may also affect the boundary layer characteristics of the blade 11 surface, such as the stability of the boundary layer and the position of the transition point, thereby affecting the generation and propagation of noise.

[0189] The trailing edge of blade 11 is the main area of ​​interaction between vortex shedding and turbulent boundary layer, and contributes greatly to the trailing edge noise. Changes in the trailing edge diameter will directly affect the frequency and intensity of vortex shedding, thereby changing the characteristics of the trailing edge noise. In addition, changes in the trailing edge diameter may also have a combined impact on aerodynamic noise and mechanical noise. A larger trailing edge diameter may increase the resistance to air flow, resulting in more energy dissipation and noise generation. At the same time, it may also change the vibration characteristics and bearing load of blade 11, thereby affecting the mechanical noise.

[0190] The influence of the leading edge diameter d3 of the blade 11 and the trailing edge diameter d4 of the blade 11 on the noise is interrelated, and they jointly determine the aerodynamic performance and noise characteristics of the blade 11. This embodiment further reduces the working noise of the crossflow impeller 1 by optimizing the leading edge diameter d3 of the blade 11 and the trailing edge diameter d4 of the blade 11.

[0191] See also Figure 8 As shown, in some preferred or alternative embodiments according to the present invention, the thickness t at the thickest part of the blade 11 is selected from any value between 1 mm and 2 mm.

[0192] In a specific embodiment, the maximum thickness t of the blade 11 is 1.6 mm.

[0193] Among them, the thickness of the blade 11 affects its interaction with the air. Thicker blades 11 may generate greater air disturbances and vortices during rotation, and the interaction and energy transfer of these vortices will increase aerodynamic noise. In particular, when the thickness of the blade 11 increases, the friction and impact between the edge of the blade 11 and the air will also increase, further exacerbating the generation of aerodynamic noise.

[0194] This embodiment further reduces the operating noise of the crossflow impeller 1 by optimizing the thickness of the blades 11 .

[0195] Fig. 9 This is a second schematic diagram of a crossflow wind wheel blade according to an embodiment of the utility model.

[0196] See also Fig. 9 As shown, in some preferred or alternative embodiments according to the present utility model,

[0197] The inlet angle of blade 11 is β, and the outlet angle of blade 11 is γ, wherein,

[0198] 0.3<β / γ<0.4.

[0199] See also Fig. 9As shown, the distance between the far side of the blade 11 and the axis is r7, the distance between the near side of the blade 11 and the axis is r8, the tangent of the characterizing section of the blade 11 at the far end is the first tangent L2, the tangent of the mid-arc line of the characterizing section at the near end is the second tangent L3, the perpendicular line of the line connecting the far end and the axis is the first perpendicular line L4, the perpendicular line of the line connecting the near end and the axis is the second perpendicular line L5, the angle β between the first perpendicular line and the first tangent is the inlet angle, and the angle γ between the second perpendicular line and the second tangent is the outlet angle. By taking reasonable values ​​for the inlet angle and the outlet angle, it is possible to ensure that the crossflow fan blade has better aerodynamic performance and improve the air outlet efficiency.

[0200] The size of the inlet angle of the blade 11 directly affects the initial impact of the airflow with the blade 11. When the inlet angle is too large or too small, the airflow may have a strong impact and separation on the surface of the blade 11, thereby forming vortices and turbulence, and increasing aerodynamic noise. A suitable inlet angle helps to maintain the stable flow of the airflow, reduce the flow separation and the generation of vortices, and thus reduce aerodynamic noise. On the contrary, an inappropriate inlet angle may cause flow instability and increase noise.

[0201] The size of the outlet angle of blade 11 affects the shedding pattern and frequency of the tail vortex. A larger outlet angle may cause the tail vortex to shed more violently and frequently, generating stronger tail vortex noise. At the same time, the interaction and energy transfer of the tail vortex may also increase aerodynamic noise. A suitable outlet angle helps to smoothly diffuse the airflow and reduce the generation of vortices and turbulence. On the contrary, an excessively large outlet angle may cause uneven diffusion of the airflow and increase aerodynamic noise.

[0202] The inlet angle refers to the angle at which the airflow enters the blade 11, which determines whether the airflow can smoothly enter the blade channel. When the inlet angle matches the airflow direction, the airflow can enter the blade 11 more smoothly, reducing impact and vortex, thereby increasing the air volume. If the inlet angle is too small or too large, it may cause the airflow to impact when entering the blade 11, increase energy loss, and reduce air volume. The inlet angle also affects the lift generation of the blade 11. The appropriate inlet angle can enable the blade 11 to more effectively capture the airflow and generate lift, thereby pushing more air through the fan or wind turbine. The design of the inlet angle has an important impact on aerodynamic efficiency. The optimized inlet angle can improve aerodynamic efficiency, reduce energy loss, and thereby increase air volume.

[0203] The outlet angle refers to the angle of the airflow when it leaves the blade 11, which determines the acceleration and diffusion of the airflow after leaving the blade 11. A larger outlet angle can make the airflow obtain a greater acceleration when leaving the blade 11, but it may also cause the airflow to diffuse too quickly, reducing the air volume. The appropriate outlet angle can balance the needs of airflow acceleration and diffusion, so that the airflow maintains a higher speed and pressure after leaving the blade 11, thereby increasing the air volume. Changes in the outlet angle will also affect the pressure distribution on the surface of the blade 11. Reasonable outlet angle design can optimize the pressure distribution, reduce the generation of vortices and turbulence, improve the stability of the airflow, and thus increase the air volume.

[0204] The effects of the inlet angle and outlet angle of the blade 11 on the noise and air volume are interrelated. They jointly determine the aerodynamic performance and noise characteristics of the blade 11. This embodiment further reduces the working noise of the crossflow impeller 1 and ensures the air volume by making the ratio of the inlet angle to the outlet angle within a reasonable range.

[0205] In some preferred or alternative embodiments of the present invention, 26°<β<27°.

[0206] In some preferred or alternative embodiments of the present invention, 83°<γ<84°

[0207] In a specific embodiment, β is 26.62°, γ is 83.69°, and β / γ=0.32.

[0208] Fig.10 Schematic block diagram of an air conditioner according to an embodiment of the present invention. Fig.10 As shown, based on the same inventive concept, the utility model also proposes an air conditioner, which includes the cross-flow impeller 1 in any of the above embodiments.

[0209] The utility model proposes a noise reduction type crossflow wind wheel 1 and an air conditioner 2 having the same. The noise reduction type crossflow wind wheel 1 comprises at least one wind wheel section 10. The wind wheel section 10 comprises a partition 12 and a plurality of blades 11 arranged circumferentially along the partition 12, wherein the suction surface of the blade 11 comprises a first arc segment a, a second arc segment b and a third arc segment c which are connected in sequence; the pressure surface of the blade 11 comprises a fourth arc segment d, a fifth arc segment e and a sixth arc segment f which are connected in sequence; the arc length of the first arc segment a is S1, the arc length of the second arc segment b is S2, and the arc length of the third arc segment c is S3; the arc length of the fourth arc segment d is S4, the arc length of the fifth arc segment e is S5, and the arc length of the sixth arc segment f is S6; wherein 0.3<S1 / S4<0.4, 2.8<S2 / S5<2.9, and 0.2<S3 / S6<0.3. Based on the technical solution proposed by the utility model, the influence of the arc length of each section of the suction surface and the arc length of each section of the pressure surface of the blade 11 on the noise and air volume is interrelated, and they jointly determine the aerodynamic performance and noise characteristics of the blade 11. By reasonably setting the arc length of each section of the suction surface and the arc length of each section of the pressure surface, the working noise of the crossflow impeller 1 is reduced without affecting the air volume.

[0210] At this point, those skilled in the art should recognize that, although multiple exemplary embodiments of the present invention have been shown and described in detail herein, many other variations or modifications that conform to the principles of the present invention can still be directly determined or derived from the contents disclosed in the present invention without departing from the spirit and scope of the present invention. Therefore, the scope of the present invention should be understood and recognized as covering all such other variations or modifications.

Claims

1. A noise reduction type crossflow wind wheel, comprising at least one wind wheel section, wherein the wind wheel section comprises a partition and a plurality of blades arranged along the circumference of the partition, characterized in that: The suction surface of the blade comprises a first arc segment, a second arc segment and a third arc segment connected in sequence; The pressure surface of the blade comprises a fourth arc segment, a fifth arc segment and a sixth arc segment which are connected in sequence; The arc length of the first arc segment is S1, the arc length of the second arc segment is S2, and the arc length of the third arc segment is S3; The arc length of the fourth arc segment is S4, the arc length of the fifth arc segment is S5, and the arc length of the sixth arc segment is S6; wherein 0.3<S1 / S4<0.4, 2.8<S2 / S5<2.9, 0.2<S3 / S6<0.

3.

2. The noise reduction crossflow impeller according to claim 1, characterized in that 1mm<S1<2mm; and / or 9mm<S2<10mm; and / or 2mm<S3<3mm; and / or 3mm<S4<4mm; and / or 3mm<S5<4mm; and / or 8mm<S6<10mm.

3. The noise reduction crossflow impeller according to claim 1, characterized in that The radius of the first arc segment is r1, the radius of the second arc segment is r2, and the radius of the third arc segment is r3; The radius of the fourth arc segment is r4, the radius of the fifth arc segment is r5, and the radius of the sixth arc segment is r6; 0.3＜r1 / r4＜0.4，0.8≤r2 / r5＜0.9，0.9＜r3 / r6＜1。 4. The noise reduction crossflow impeller according to claim 3, characterized in that 7mm<r1<8mm; and / or 12mm<r2<13mm; and / or 9mm<r3<10mm; and / or 19mm<r4<20mm; and / or 15mm<r5<16mm; and / or 9mm<r5<11mm.

5. The noise reduction crossflow impeller according to claim 1, characterized in that The chord length of the first arc segment is P1, the chord length of the second arc segment is P2, and the chord length of the third arc segment is P3; The chord length of the fourth arc segment is P4, the chord length of the fifth arc segment is P5, and the chord length of the sixth arc segment is P6; 0.3<P1 / P4<0.4, 2.7<P2 / P5<2.8, 0.4<P3 / P6<0.

5.

6. The noise reduction crossflow impeller according to claim 1, characterized in that 1mm<P1<2mm; and / or 9mm<P2<10mm; and / or 2mm<P3<3mm; and / or 3mm<P4<4mm; and / or 3mm<P5<4mm; and / or 5mm<P6<6mm.

7. The noise reduction crossflow impeller according to claim 1, characterized in that The leading edge diameter d3 of the blade is selected from any value between 0.5 mm and 1 mm; and / or The trailing edge diameter d4 of the blade is selected from any value between 1 mm and 2 mm.

8. The noise reduction crossflow impeller according to claim 1, characterized in that The thickness of the thickest part of the blade is selected from any value between 1 mm and 2 mm.

9. The noise reduction crossflow impeller according to claim 1, characterized in that The number of the blades is an odd number, the number of the blades is Y, and 32<Y<38.

10. An air conditioner, characterized in that: It comprises a noise reducing crossflow impeller as described in any one of claims 1 to 9.

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