JP6379788B2 - Cross flow fan and air conditioner equipped with the same - Google Patents

Description

  The present invention relates to a cross flow fan and an air conditioner including the same.

  In the conventional cross-flow fan, various techniques have been proposed to reduce noise generated over a wide band when the airflow passes through the impeller, that is, so-called broadband sound.

  For example, in the crossflow fan described in Patent Document 1, in a configuration in which a plurality of impellers are arranged side by side in the rotation axis direction, the outer edges of the blades constituting each impeller are notched at a predetermined interval. By providing, broadband sound is reduced.

Japanese Patent No. 4432865

  However, in the configuration in which notches are provided at predetermined intervals on the outer edges of the blades in order to reduce broadband sound as described above, when the number of impellers is reduced by increasing the length of the blades, Since the continuous part in an outer edge becomes long, there exists a problem that NZ sound becomes loud.

  The present invention has been made in view of the above circumstances, and suppresses an increase in NZ sound even if the number of impellers is reduced by lengthening the blades in a crossflow fan in which broadband sound is reduced. An object of the present invention is to provide a cross flow fan capable of performing the above.

In order to solve the above problems, a crossflow fan (3) of the present invention is a crossflow fan (3) including an impeller (39) having a plurality of blades (31), Oite the outer edge (46) of 31), said a along a direction extending first notch at a predetermined interval (34) is provided blades (31), said first notch of adjacent (34) A plurality of second cutouts (35) having a depth smaller than that of the first cutout (34) are provided therebetween.

In the present invention, in a configuration for reducing the wideband noise by first notches (34) are provided at predetermined intervals along the direction of extension of the blade Oite blade (31) to the outer edge (46) of (31) Furthermore, a plurality of second notches (35) having a shallow depth are interposed between the first notches (34). Accordingly, even if the blade (31) is lengthened and the number of impellers (39) is reduced , the continuous portion of the outer edge (46 ) of the blade (31) is formed by the plurality of second notches (35). As a result, it is possible to suppress an increase in NZ sound.

  The second cutout (35) preferably has a triangular shape.

According to this configuration, the second notch (35) has a simple shape and is easy to process. In addition, the triangular second notch (35) can reduce the continuous portion of the outer edge (46 ) even if the opening area is small. Therefore, it is possible to secure an area where the blades (31) work while reducing NZ noise.

Moreover, it is preferable that the outer edge (46 ) of the said blade | wing (31) has a smooth part (36) between the said 1st notches (34).

According to this configuration, the outer edge (46 ) of the blade (31) has the smooth portion (36) between the first cutouts (34), so that the plurality of second cutouts (35) It is possible to secure an area where the blades (31) work while reducing the NZ sound. Moreover, it is possible to reduce the crack of the outer edge (46 ) of the blade (31).

  The opening area of the second notch (35) is preferably smaller than the opening area of the first notch (34).

  According to such a configuration, it is possible to secure an area where the blades (31) work while reducing the NZ sound by the second notch (35). As a result, the cross flow fan (such as the blowing pressure) ( It is possible to suppress the reduction in the performance of 3). Further, since the opening area of the second notch (35) is small, the influence on the effect of reducing the broadband sound by the first notch (34) is small.

  Moreover, it is preferable that the depth of the said 2nd notch (35) is 1 mm or less.

  According to this configuration, if the depth of the second notch (35) is 1 mm or less, the area where the blade (31) works while reducing the NZ sound by the second notch (35). As a result, it is possible to suppress a reduction in the performance of the cross flow fan (3) such as the blowing pressure. Further, since the depth of the second notch (35) is 1 mm or less, the influence on the effect of reducing the broadband sound by the first notch (34) is small.

  The air conditioner (1) of the present invention includes the cross flow fan (3). Thereby, even if the blade (31) is lengthened and the number of impellers (39) is reduced, it is possible to suppress the increase in NZ sound.

  According to the present invention, an increase in NZ sound can be suppressed even if the blades are lengthened and the number of impellers is reduced in a crossflow fan in which broadband sound is reduced.

It is sectional drawing which shows the indoor unit of an air conditioner provided with the crossflow fan which concerns on embodiment of this invention. It is a front view which shows the crossflow fan of FIG. It is an expansion perspective view of the blade | wing of the crossflow fan of FIG. It is sectional drawing in the position of the 1st notch in the blade | wing of FIG. It is a front view of the 1st notch and 2nd notch of the blade | wing of FIG. FIG. 6 is an enlarged front view of the first notch and the second notch of FIG. 5. It is a graph which shows the characteristic of the cross flow fan shown in FIG. It is a graph which shows the characteristic of the cross flow fan shown in FIG. It is an enlarged front view which shows the 2nd notch of the square shape of the blade | wing in the crossflow fan which concerns on the modification of this invention, and the 2nd notch of a waveform shape.

  Hereinafter, a cross flow fan 3 according to an embodiment of the present invention and an indoor unit 1 of an air conditioner including the same will be described with reference to the drawings.

[Air conditioner]
FIG. 1 is a cross-sectional view showing an indoor unit 1 of an air conditioner including a cross flow fan 3 according to an embodiment of the present invention. The cross section shown in FIG. 1 is a cross section orthogonal to the axial direction of the cross flow fan 3. The air conditioner includes an indoor unit 1 and an outdoor unit (not shown). In the present embodiment shown in FIG. 1, the indoor unit 1 is a wall-hanging type, but is not limited to this. The indoor unit 1 may be, for example, a floor-standing type or a ceiling-mounted type. The indoor unit 1 is connected to the outdoor unit through a refrigerant pipe. The outdoor unit includes an unillustrated evaporator, a heat exchanger, a fan, and the like. The air conditioner includes a refrigerant circuit that performs a vapor compression refrigeration cycle.

[Indoor unit]
As shown in FIG. 1, the indoor unit 1 includes a casing 10, a blower mechanism 2 including a cross flow fan 3, a heat exchanger 7, an air filter 8, a drain pan 11, and the like that are housed in the casing 10. Prepare. The casing 10 includes a front panel 10F, a back panel 10R, a top panel 10T, a bottom panel 10B, and the like. The casing 10 has an air inlet 12 and an air outlet 13. In the present embodiment, the suction port 12 is formed between the front panel 10F and the top panel 10T, and the air outlet 13 is formed between the front panel 10F and the bottom panel 10B. I can't.

  An air filter 8 is disposed on the downstream side of the suction port 12 so as to face the suction port 12. A heat exchanger 7 is disposed further downstream of the air filter 8. The room air that passes through the suction port 12 and reaches the heat exchanger 7 passes through the air filter 8 and dust is removed.

  The heat exchanger 7 includes a front side heat exchanger 7A provided on the front panel 10F side in the casing 10 and a back side heat exchanger 7B provided on the back panel 10R side. These heat exchangers 7A and 7B extend along the width direction of the casing 10, and are provided in an inverted V shape in the cross-sectional view shown in FIG. For example, a fin-and-tube type heat exchanger can be used as the heat exchanger 7, but the heat exchanger 7 is not limited thereto.

  The fin-and-tube type heat exchanger 7 includes a plurality of heat transfer tubes 71 and a plurality of fins 72 arranged along the longitudinal direction of the heat transfer tubes 71. In the present embodiment shown in FIG. 1, a plurality of rows are formed by a plurality of heat transfer tubes 71 in the front side heat exchanger 7 </ b> A, and a plurality of rows are also formed by a plurality of heat transfer tubes 71 in the back side heat exchanger 7 </ b> B. A column is formed. Specifically, the back-side heat exchanger 7B has three rows of heat transfer tubes 71 and two rows. In the portion surrounded by the drain pan 11B, there are two rows of the heat transfer tubes 71, and above this portion, three rows of the heat transfer tubes 71 are provided.

  The drain pan 11 includes a front side drain pan 11A disposed along the lower end portion of the front side heat exchanger 7A and a back side drain pan 11B disposed along the lower end portion of the back side heat exchanger 7B.

  The blower mechanism 2 forms an airflow F that flows in the order of the suction port 12, the heat exchanger 7, and the air outlet 13 as indicated by arrows in FIG. 1. The blower mechanism 2 includes a crossflow fan 3 having a plurality of crossflow impellers 39, a rear guider 4 (back scroll 4), and a stabilizer 6 (tongue 6). In the embodiment shown in FIG. 1, the heat exchanger 7 and the air blowing mechanism 2 are arranged so that the heat exchanger 7 covers the upper part of the air blowing mechanism 2, but the arrangement is not limited thereto.

  As shown in FIG. 2, in the present embodiment, the cross flow fan 3 has a substantially cylindrical shape. The cross flow fan 3 extends long along the width direction of the casing 10 and is provided in parallel with the width direction of the casing 10.

  The cross flow fan 3 partitions a pair of end plates 33 that are spaced apart from each other, a plurality of impellers 39 that are linearly arranged between the pair of end plates 33, and the impeller 39. And a partition 32.

  The plurality of impellers 39 are arranged side by side along the rotation axis 3 </ b> A of the cross flow fan 3. Each impeller 39 has a substantially cylindrical shape. Each impeller 39 has a plurality of blades 31. The partition 32 is provided between the respective impellers 39. The pair of end plates 33 are disposed at both ends of the cross flow fan 3. These end plates 33 close end portions on the outer side in the axial direction of the impellers 39 located at both ends. Both ends of each blade 31 are fixed to a partition 32 or an end plate 33. The blade 31 extends along the axial direction of the impeller 39.

  One end plate 33 has a shaft portion 38 disposed on the rotation shaft 3A. The shaft portion 38 is supported by the casing 10, for example. A motor 37 is arranged on the other end plate 33 side. The cross flow fan 3 is rotated by the driving force of the motor 37. In the present embodiment, the cross flow fan 3 is disposed on the downstream side in the direction in which air flows with respect to the heat exchanger 7, but is not limited thereto, and is disposed on the upstream side of the heat exchanger 7. May be.

  As shown in FIG. 1, the plurality of blades 31 of each impeller 39 are arranged along the circumferential direction around the rotation shaft 3 </ b> A of the cross flow fan 3. Adjacent blades 31 are arranged at a predetermined interval. Each blade 31 is a forward blade that curves in the rotational direction D as it goes radially outward. Each blade 31 has a pressure surface 41 and a negative pressure surface 42 as shown in FIGS. The pressure surface 41 is a surface on the rotation direction D side of the cross flow fan 3, and the negative pressure surface 42 is a surface opposite to the rotation direction D of the cross flow fan 3. The negative pressure surface 42 is a convex curved surface that is convex on the opposite side of the rotation direction D. The pressure surface 41 is a concave curved surface that is recessed on the opposite side of the rotation direction D.

  3-6, the outer edge 46 of each blade | wing 31 is provided with the 1st notch 34 with the predetermined space | interval X0 along the direction A where the blade | wing 31 is extended. Furthermore, a plurality of (three in FIG. 3) second notches 35 smaller than the first notches 34 are provided between the adjacent first notches 34.

  Each of the first notch 34 and the second notch 35 has a triangular shape. That is, the first notch 34 and the second notch 35 have a shape such that the width becomes narrower from the outer edge 46 to the inner edge 47 of the blade 31. The opening angle of the hypotenuse at the back ends of the first notch 34 and the second notch 35 is set to, for example, about 50 to 70 degrees (preferably around 60 degrees), but the present invention is not limited to this. It is not something. More specifically, by setting the opening angle to 60 degrees, the first notch 34 and the second notch 35 may be formed in an equilateral triangle shape. The angular portions of the first notch 34 and the second notch 35 may be appropriately chamfered.

  The depth Y2 of the second notch 35 is set to be shallower than the depth Y1 of the first notch 34. For example, the depth Y2 is set to about 0.25 to 0.75 times (preferably around 0.5 times) the depth Y1, but the present invention is not limited to this. The “depth” here is defined by, for example, the length of a line perpendicular to the outer edge 46 of the blade 31.

  If the depth Y2 of the second notch 35 is set to 1 mm or less, the area where the blades 31 work can be ensured while the NZ noise is reduced by the second notch 35.

  Similarly, in the direction A in which the outer edge 46 extends, the width X2 of the second notch 35 is set to be narrower than the width X1 of the first notch 34. For example, the width X2 is set to about 0.25 to 0.75 times (preferably around 0.5 times) the width X1, but the present invention is not limited to this.

  The opening area S2 of the second notch 35 is set to be smaller than the opening area S1 of the first notch 34. Here, as shown in FIG. 4, the opening area S <b> 1 is the first viewed from the extending direction B of the line q perpendicular to the tangent line p to the pressure surface 41 at the back end 34 a of the first notch 34. The opening area of the notch 34 is said. The opening area S2 of the second notch 35 is also defined in the same manner as the opening area S1 and refers to the opening area of the second notch 35 viewed from the direction B.

  The outer edge 46 of each blade 31 has a smooth portion 36 between the first cutouts 34. The smooth portion 36 forms a part of the outer edge 46. The length X3 of the smoothing portion 36 is a parameter that affects the area on which the blades 31 work. The distance X0 between the first notches 34, the width X1 of the first notches 34, and the second notches. It is set based on a width X2 of 35.

  In addition, the negative pressure surface 42 of each blade 31 is formed with a groove 43 that continues from the first notch 34 and extends in a direction from the outer edge 46 to the inner edge 47 by a predetermined length. As shown in FIG. 4, the depth of the groove 43 is deepest near the first notch 34 and gradually becomes shallower from the outer edge 46 toward the inner edge 47. Therefore, the step between the first notch 34 and the groove 43 is small. As a result, the airflow can flow smoothly from the first notch 34 to the groove 43, and the loss due to the collision between the airflow and the step at the step between the first notch 34 and the groove 43 is suppressed, It is possible to suppress the performance degradation of the cross flow fan 3.

  A plurality of indentations 45 are formed in a portion between the two grooves 43 on the suction surface 42 of each blade 31. The airflow flowing along the suction surface 42 is changed to turbulent flow by the boundary layer being disturbed by the secondary flow generated in the recess 45, and the air flow deceleration in the boundary layer is reduced. It is possible to suppress the peeling from the pressure surface 42 and to suppress the performance deterioration of the cross flow fan 3.

  As shown in FIG. 1, the rear guider 4 has a facing surface 40 that faces the cross flow fan 3 in the radial direction. The facing surface 40 functions as a guide surface that guides the airflow F formed by the cross flow fan 3 to the air outlet 13. The facing surface 40 is a concave curved surface that is located on the radially outer side of the cross flow fan 3 and is recessed radially outward. The facing surface 40 is provided with a gap between it and the cross flow fan 3.

  The stabilizer 6 is disposed on the outer side in the radial direction of the cross flow fan 3 with a gap between the stabilizer 6 and the cross flow fan 3. The stabilizer 6 and the rear guider 4 are provided so as to sandwich the cross flow fan 3 therebetween. The stabilizer 6 has a surface 6a close to the cross flow fan 3 on the side opposite to the rear guider 4 (in the present embodiment, the front panel 10F side) with respect to the cross flow fan 3.

  When the cross flow fan 3 having a plurality of impellers 39 is rotated by the motor 37 in the rotation direction D of the solid line arrow shown in FIG. 1, an air flow F shown in FIG. 1 is formed. That is, indoor air is sucked into the casing 10 through the suction port 12 provided in the casing 10. The sucked air undergoes heat exchange with the refrigerant when passing through the heat exchanger 7, and the temperature is adjusted. The temperature-adjusted air passes through the cross flow fan 3 of the blower mechanism 2 and is blown out into the room from the air outlet 13 provided in the casing 10.

  Next, the characteristics of the cross flow fan 3 of the present embodiment will be described with reference to the graphs of FIGS.

  7 to 8 show the characteristics of the cross flow fan 3 of the present embodiment in which the first notch 34 and the second notch 35 shown in FIG. It is the graph which compared the characteristic of the cross flow fan which has the normal blade | wing which does not have these 1st notches 34 and 2nd notches 35. FIG.

  FIG. 7 shows the result of spectral comparison of the blowing sound with the same air volume in the cross flow fan 3 of this embodiment and the cross flow fan of the reference example. As shown in FIG. 7, the cross flow fan 3 according to the present embodiment in which the first notch 34 and the second notch 35 are provided on the outer edge 46 of the blade 31 has NZ sound compared to the reference example. It can be seen that the noise level is significantly reduced at a frequency related to (a frequency slightly lower than 700 Hz (specifically, a range indicated by a broken-line rectangle shown in FIG. 7)). FIG. 8 is a comparison of noise levels at frequencies including NZ sounds in the spectrum shown in FIG. As shown in FIG. 8, in the cross flow fan 3 of the present embodiment, the noise level of the blowing sound is reduced by about 1.3 dBA at the frequency including the NZ sound as compared with the cross flow fan of the reference example. I understand.

(Feature)
(1)
In the cross flow fan 3 of the present embodiment, in the configuration in which the first cutouts 34 are provided at predetermined intervals along the extending direction A of the blades 31 at the outer edge 46 of the blades 31, A second notch 35 having a shallow depth is interposed between the first notches 34. Accordingly, even if the length L1 of the blade 31 is increased and the number of the impellers 39 is reduced as shown in FIG. 2, the continuous portion of the outer edge 46 of the blade 31 is reduced by the second notch 35. As a result, an increase in NZ sound can be suppressed.

(2)
In the crossflow fan 3 of the present embodiment, the second notch 35 has a triangular shape and is easy to process since it has a simple shape. Moreover, the triangular second notch 35 can reduce the continuous portion of the outer edge 46 even if the opening area is small. Therefore, it is possible to secure an area where the blades 31 work while reducing NZ noise.

(3)
In the cross flow fan 3 according to the present embodiment, the outer edge 46 of the blade 31 has the smooth portion 36 between the first notches 34. Therefore, the second notch 35 reduces the NZ noise while reducing the blade 31. It is possible to secure a work area. Moreover, it is possible to reduce the crack of the outer edge 46 of the blade 31.

(4)
In the cross flow fan 3 of the present embodiment, since the opening area S2 of the second notch 35 is smaller than the opening area S1 of the first notch 34, the NZ noise is reduced by the second notch 35. It is possible to secure an area where the blades 31 work. As a result, it is possible to suppress a reduction in the performance of the cross flow fan 3 such as the blowing pressure. Further, since the opening area of the second notch 35 is small, the influence on the effect of reducing the broadband sound by the first notch 34 is small.

(5)
In the cross flow fan 3 of the present embodiment, the depth Y2 of the second notch 35 is 1 mm or less, so that the area where the blades 31 work is secured by the second notch 35 while reducing NZ noise. As a result, it is possible to suppress a reduction in the performance of the cross flow fan 3 such as the blowing pressure. Further, since the depth of the second notch 35 is 1 mm or less, the influence on the effect of reducing the broadband sound by the first notch 34 is small.

(6)
Since the air conditioner 1 of the present embodiment includes the cross flow fan 3 described above, even if the length L1 of the blades 31 is increased and the number of impellers 39 is reduced, an increase in NZ noise can be suppressed. Is possible.

(Modification)
(A)
In the above embodiment, an example in which the second notch 34 has a triangular shape is shown, but the present invention does not limit the shape of the second notch to this. As a modification of the present invention, for example, as shown in FIG. 9, a square-shaped second notch 51 may be provided between the first notches 34. Since the smooth portion 52 is provided between the second cutouts 51, it is possible to secure an area where the blades 31 work while reducing the NZ sound by the second cutouts 51.

Further, although not included in the embodiment, a corrugated second notch 61 may be provided by forming one wide recess between the first notches 34. The inner wall 61a of the second notch 61 has a linear shape or a gentle curved shape. The depth of the second notch 61 is set to be shallower than the depth of the first notch 34. In such a single wide second notch 61, since there is no fine unevenness, the inner wall 61a of the second notch 61 reduces the NZ sound while the smooth portion 36 (see FIG. 6). It is possible to secure the area where the blades 31 work by performing the above function. In addition, since the second notch 61 has no fine irregularities, it has an advantage that dust does not collect easily.

(B)
Note that the present invention is not limited to the second notch 35 being formed between all the first notches 34. For example, the second notch 35 may be omitted at a position closest to both ends of the blade 31. Alternatively, every other second notch 35 may be formed between adjacent first notches 34.

(C)
In the above embodiment, the first notch 34 and the second notch 35 are formed only on the outer edge 46 of the blade 31, but the present invention is not limited to this. The first notch 34 and second notch 35 may be formed on both the outer 46 and inner edge 47 of the blades 31. In these cases as well, the increase in NZ noise can be suppressed even if the blades 31 are lengthened and the number of impellers 39 is reduced in the cross-flow fan in which broadband sound is reduced, as in the above embodiment. Can do.

(D)
In the above embodiment, the outer edge 46 of the blade 31 has the smooth portion 36 between the first notches 34, but the present invention is not limited to this. The blade | wing 31 may be a form without the smooth part 36. FIG.

(E)
In the above embodiment, the opening area S2 of the second notch 35 is set to be smaller than the opening area S1 of the first notch 34, but the present invention is not limited to this. Absent. The opening area S2 of the second notch 35 may be larger than the opening area S1 of the first notch 34.

DESCRIPTION OF SYMBOLS 1 Indoor unit 3 Cross flow fan 31 Blade | wing 34 1st notch 35 2nd notch 36 Smoothing part 39 Impeller 46 Outer edge 47 Inner edge

Claims (6)

A cross flow fan (3) comprising an impeller (39) having a plurality of blades (31),
Oite the outer edge (46) of the vane (31), first notch (34) is provided at the predetermined intervals along the extending direction of the blade (31),
A plurality of second cutouts (35) having a depth smaller than that of the first cutouts (34) are provided between the adjacent first cutouts (34).
Cross flow fan (3) characterized by this. The second notch (35) has a triangular shape,
The crossflow fan (3) according to claim 1. The outer edge (46 ) of the blade (31) has a smooth portion (36) between the first notches (34).
The crossflow fan (3) according to claim 1 or 2. An opening area of the second notch (35) is smaller than an opening area of the first notch (34);
The crossflow fan (3) according to any one of claims 1 to 3. The depth of the second notch (35) is 1 mm or less,
The crossflow fan (3) according to any one of claims 1 to 4.   An air conditioner (1) comprising the crossflow fan (3) according to any one of claims 1 to 5.

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