JP7551291B2 - Crossflow fan and indoor unit of air conditioner - Google Patents

Description

The present invention relates to a crossflow fan and an indoor unit of an air conditioner.

Crossflow fans are known as fans used in indoor units of air conditioners. Unlike axial fans and centrifugal fans, crossflow fans are long in the width direction (direction of rotation axis). In addition, crossflow fans have multiple blades arranged in the circumferential direction, but they generate a unique sound called NZ sound, which has a frequency equal to the product of the crossflow fan's rotation speed N and the number of blades Z.

To suppress the generation of such NZ noise, it is known to make the pitch of the blades of a crossflow fan uneven rather than uniform (for example, see Patent Document 1). Patent Document 1 discloses that the arc blades are arranged at a random pitch in the circumferential direction, and the impeller is shifted in position by 1 to 4 degrees in the circumferential direction.

Patent No. 2770677

However, simply making the blade pitch uneven may not be enough to make the wind generated by rotating the crossflow fan sufficiently irregular, and may not be able to sufficiently suppress NZ noise.
Furthermore, since the generated wind cannot be made sufficiently irregular, a user who is directly exposed to the wind from the crossflow fan may experience a sensation different from natural wind (e.g., a sensation of artificial wind), which may reduce the user's comfort.

The present invention has been made in consideration of the above circumstances, and aims to provide a crossflow fan and an indoor unit of an air conditioner that can reduce the NZ noise generated due to the rotation of the crossflow fan.
Another object of the present invention is to provide a crossflow fan and an indoor unit of an air conditioner that can improve user comfort, which has been made in consideration of the above circumstances.

In order to solve the above problems, the crossflow fan and the indoor unit of the air conditioner according to the present invention employ the following measures.
A crossflow fan according to one aspect of the present invention is a crossflow fan having a cylindrical outer shape formed by arranging multiple blades in an annular manner around a rotation axis and blowing out a fluid introduced inside to the outside by rotation around the rotation axis, the multiple blades having a first blade and a second blade, the first blade and the second blade being arranged such that, in a plane perpendicular to the rotation axis, r1 is the distance between an inner end of the first blade and the rotation axis, r2 is the distance between an inner end of the second blade and the rotation axis, R1 is the distance between an outer end of the first blade and the rotation axis, and R2 is the distance between the outer end of the second blade and the rotation axis, such that r2≦r1 and R2<R1.

In the above configuration, in a plane perpendicular to the rotation axis, the distance r1 between the inner end of the first blade and the rotation axis is equal to or greater than the distance between the inner end of the second blade and the rotation axis. Also, the distance R1 between the outer end of the first blade and the rotation axis is greater than the distance R2 between the outer end of the second blade and the rotation axis. Therefore, the first blade is located radially outward of the second blade. In other words, the first blade and the second blade are arranged so as to be shifted in the radial direction. When such a crossflow fan rotates, wind is generated by both the first blade and the second blade. When wind is generated by both the first blade and the second blade, the wind generated by the first blade and the wind generated by the second blade interfere with each other. When the wind from the first blade and the wind from the second blade interfere with each other, the interfering winds become irregular and turbulent. Therefore, the wind generated from the entire crossflow fan can be made irregular, so that the NZ sound generated due to the rotation of the crossflow fan can be reduced.
In addition, the wind generated by the crossflow fan is irregular as described above, and is therefore close to natural wind. Therefore, for example, when there is a user who is directly exposed to the wind from the crossflow fan, the sensation of the user receiving the wind can be made to be close to the sensation of receiving natural wind, thereby improving the comfort of the user.

In addition, in a crossflow fan according to one aspect of the present invention, the first blade and the second blade may be arranged such that a first virtual line connecting the first blade and the rotation axis and a second virtual line connecting the second blade and the rotation axis are in different directions.

In the above configuration, the first blade and the second blade are arranged so that the first imaginary line connecting the first blade and the rotation axis and the second imaginary line connecting the second blade and the rotation axis are in different directions. That is, the first blade and the second blade are arranged so that their positions are shifted in the circumferential direction. In other words, the first blade and the second blade are arranged so that the first blade and the second blade do not overlap when viewed radially outward from the rotation axis, and a gap is generated between the first blade and the second blade. This allows wind to pass between the first blade and the second blade. Therefore, the wind generated by the first blade and the wind generated by the second blade are more likely to interfere with each other. Therefore, the wind generated by the entire crossflow fan can be made irregular, and the NZ sound generated due to the rotation of the crossflow fan can be reduced.

In addition, in a crossflow fan according to one aspect of the present invention, the first blades are arranged in a plurality of pieces around the rotation axis, and the second blades are arranged in a plurality of pieces around the rotation axis, and the number of the first blades and the number of the second blades may be different.

In the above configuration, the number of first blades and the number of second blades are different. As a result, when a plurality of first blades and second blades are arranged in a line around the rotation axis, the circumferential positions of the first blades and the second blades are shifted. That is, when viewed radially outward from the rotation axis, a gap is generated between the first blades and the second blades. In addition, since the number of first blades and the number of second blades are different, the length (circumferential length) of each gap is different. Wind that passes through gaps of different lengths has a different vector after passing through. Therefore, the regularity of the vector is reduced, and the wind generated from the entire crossflow fan can be made more preferably irregular.

In addition, in a crossflow fan according to one aspect of the present invention, the number of the first blades may be greater than the number of the second blades.

In the above configuration, the number of second blades provided on the inside in the radial direction is smaller than the number of first blades provided on the outside in the radial direction. In other words, the first blades, which have a larger number, are arranged in a line around the rotation axis on the outer circumferential portion, which has a larger area, and the second blades, which have a smaller number, are arranged in a line around the rotation axis on the inner circumferential portion, which has a smaller area. This makes it possible to increase the distance between adjacent blades. This makes it possible to prevent the blades from being too close to each other and preventing proper air blowing.

An indoor unit of an air conditioner according to one aspect of the present invention is equipped with any of the cross-flow fans described above.

In the above configuration, the wind generated by the crossflow fan can be made to be close to natural wind. Therefore, even if the user directly receives the wind supplied from the indoor unit to the room, the sensation of the user receiving the wind can be made to be close to the sensation of receiving natural wind. This can improve the comfort of the user.

According to the present invention, it is possible to reduce the NZ noise caused by the rotation of the crossflow fan.
Furthermore, according to the present invention, it is possible to improve the comfort of the user.

1 is a perspective view of an indoor unit of an air conditioner according to an embodiment of the present invention. FIG. 2 is a vertical cross-sectional view of an indoor unit of the air conditioner of FIG. 1 . FIG. 2 is an enlarged view of a main portion of a cross-flow fan used in the air conditioner of FIG. 1 .

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a cross flow fan and an indoor unit for an air conditioner according to the present invention will be described with reference to the drawings.
Fig. 1 shows a perspective view of an indoor unit of an air conditioner according to one embodiment of the present invention, and Fig. 2 shows a vertical cross-sectional view of the indoor unit. Note that in this embodiment, an example in which the invention is applied to a wall-mounted indoor unit will be described, but the type of indoor unit is not limited to the wall-mounted type, and it goes without saying that the invention can also be applied to other types of indoor units.

The indoor unit 1 has a housing 2 in the shape of a horizontally long rectangular parallelepiped. This housing 2 is composed of a base 3 that forms the rear side of the housing 2, a front panel 4 that covers the front side of the base 3, an intake panel 6 that covers a front opening 5 of the front panel 4, and an exhaust grill 7 that is disposed between the front and bottom surfaces of the front panel 4.

The base 3 is integrally molded with a rear drain pan 8 that receives drain water flowing down from a second heat exchanger 17B that constitutes an indoor heat exchanger 17 described below, an air flow path wall 9 that forms an outlet flow path 20A for air blown out from a crossflow fan 18 described below, and a piping housing 11 that houses refrigerant piping 10. The front panel 4 has an intake grill 12 formed on the upper surface, and an intake panel 6 is installed in front of the front opening 5 so that it can be opened and closed upward with its upper part as a fulcrum, and an intake port 13 is opened in the lower part. In addition, an outlet grill 7 disposed between the front and lower surfaces of the front panel 4 has an outlet port 14 opened.

Inside the housing 2, an air filter 15 and an air purification filter 16 are arranged along the front opening 5 and the intake grille 12 of the front panel 4 including the intake port 13, and a plate fin tube type indoor heat exchanger 17 is arranged in the ventilation passage 20 downstream of the air filter 15 and the air purification filter 16. As shown in FIG. 2, the indoor heat exchanger 17 is divided into a first heat exchanger 17A arranged on the front side and a second heat exchanger 17B arranged on the rear side, and the lower part of the first heat exchanger 17A on the front side is bent into a dogleg shape. The upper end of the first heat exchanger 17A and the upper end of the second heat exchanger 17B are connected by a bracket 24.

The indoor heat exchanger 17, which is divided or folded into multiple pieces, is arranged in the housing 2 so that its cross section is inverted V-shaped from the lower front to the top and back sides. In other words, the first heat exchanger 17A arranged on the front side of the indoor heat exchanger 17 and the second heat exchanger 17B arranged on the back side are arranged so that their upper ends are close to each other and the distance between them gradually increases as they go downward, forming a so-called inverted V-shaped arrangement.

The indoor heat exchanger 17 also has multiple tubes 17C through which the refrigerant flows and which extend in a predetermined direction (the longitudinal direction of the indoor unit 1), and multiple plate-shaped fins 17D arranged perpendicular to the extension direction of the tubes 17C. The multiple fins 17D are arranged parallel to each other and spaced a predetermined distance apart. Each of the multiple tubes 17C passes through a through hole formed in the fins 17D.

A cross-flow fan 18 having an elongated cylindrical shape is disposed in the ventilation passage 20 downstream of the indoor heat exchanger 17 so as to be rotatable about a rotation axis C (horizontal axis). Details of the cross-flow fan 18 will be described later.

A stabilizer 19 molded integrally with the outlet grille 7 is disposed downstream and forward of the crossflow fan 18, and the stabilizer 19 and the air flow path wall 9 molded on the base 3 form an outlet flow path 20A leading to the outlet 14.

The front drain pan 21 that receives drain water flowing down from the first heat exchanger 17A that constitutes the indoor heat exchanger 17 is molded integrally with the stabilizer 19 on the outlet grill 7. In addition, the outlet grill 7 is provided with a plurality of rotatable vertical louvers 22 that adjust the direction of the temperature-controlled air blown out from the air outlet 14 in the left-right direction, and a rotatable horizontal flap 23 that adjusts the direction of the temperature-controlled air in the up-down direction.

Next, the cross flow fan 18 according to this embodiment will be described with reference to FIGS.
The crossflow fan 18 has a cylindrical outer shape with a plurality of blades (first blade 25 and second blade 26 described later) arranged in an annular shape around a rotation axis C. The crossflow fan 18 is arranged in the space inside the housing 2 such that the upper and front sides are covered by the indoor heat exchanger 17 (specifically, the first heat exchanger 17A and the second heat exchanger 17B). The crossflow fan 18 is a cylindrical member whose rotation axis C extends in the longitudinal direction of the indoor unit 1. The crossflow fan 18 is driven to rotate around the rotation axis C, thereby introducing air into the housing 2 from the suction port 13 and discharging the introduced air from the air outlet 14 to the outside of the housing 2 (the room where the indoor unit 1 is arranged).

The crossflow fan 18 has a number of first blades 25 provided on the outer periphery of a plane perpendicular to the rotation axis C, and a number of second blades 26 arranged on the inner periphery side of the first blades 25 (i.e., on the rotation axis C side). Each of the first blades 25 and second blades 26 extends in the radial direction (i.e., in the direction perpendicular to the rotation axis C) from one end to the other end in the air flow direction. Each of the first blades 25 and second blades 26 also extends a predetermined length in the direction of the rotation axis C.

In this embodiment, 35 first blades 25 are provided. The multiple first blades 25 are arranged in a line in the circumferential direction around the rotation axis C at a predetermined interval. In detail, the first blades 25 are arranged in a line in the circumferential direction so that the distance r1 between the inner end 25a and the rotation axis C and the distance R1 between the outer end 25b and the rotation axis C are the same. In addition, the multiple first blades 25 are arranged so that the pitches between adjacent first blades 25 are equal.

In this embodiment, 29 second blades 26 are provided. The multiple second blades 26 are arranged in a line in the circumferential direction around the rotation axis C at a predetermined interval. In detail, the second blades 26 are arranged in a line in the circumferential direction so that the distance r2 between the inner end 26a and the rotation axis C and the distance R2 between the outer end 26b and the rotation axis C are the same. The multiple second blades 26 are also arranged so that the pitches between adjacent second blades 26 are equal. The multiple second blades 26 are arranged away from the rotation axis C.

Next, the positional relationship between the first blade 25 and the second blade 26 will be described with reference to Fig. 3. Fig. 3 illustrates one first blade 25 and a second blade 26 adjacent to the first blade 25 when viewed radially outward from the rotation axis C.
As shown in FIG. 3, the first blade 25 and the second blade 26 are arranged so as to satisfy the following formulas (1) and (2).
r2<r1...(1)
R2<R1...(2)
where r1 is the distance between the inner end 25a of the first blade 25 and the rotation axis C, r2 is the distance between the inner end 26a of the second blade 26 and the rotation axis C, R1 is the distance between the outer end 25b of the first blade 25 and the rotation axis C, and R2 is the distance between the inner end 26a of the second blade 26 and the rotation axis C.

That is, the first blade 25 is located radially outward of the second blade 26. In other words, the first blade 25 and the second blade 26 are arranged so as to be offset in the radial direction.

The first blade 25 and the second blade 26 are arranged such that a first virtual line (dashed line r1 in FIG. 1 ) connecting the inner end 25a of the first blade 25 to the rotation axis C and a second virtual line (dashed line r2 in FIG. 1 ) connecting the inner end 26a of the second blade 26 to the rotation axis C are in different directions. That is, the first virtual line (dashed line r1 in FIG. 1 ) and the second virtual line (dashed line r2 in FIG. 1 ) are arranged so as not to overlap. Similarly, the first blade 25 and the second blade 26 are arranged such that a virtual line (dashed line R1 in FIG. 1 ) connecting the outer end 25b of the first blade 25 to the rotation axis C and a virtual line (dashed line R2 in FIG. 1 ) connecting the outer end 26b of the second blade 26 to the rotation axis C are arranged in different directions.
That is, the first blade 25 and the second blade 26 are disposed adjacent to each other when viewed radially outward from the rotation axis C.

According to this embodiment, the following advantageous effects are obtained.
In this embodiment, in a plane perpendicular to the rotation axis C, the distance r1 between the inner end 25a of the first blade 25 and the rotation axis C is equal to or greater than the distance between the inner end 26a of the second blade 26 and the rotation axis C. In addition, the distance R1 between the outer end 25b of the first blade 25 and the rotation axis C is greater than the distance R2 between the outer end 26b of the second blade 26 and the rotation axis C. Therefore, the first blade 25 is located radially outward from the second blade 26. In other words, the first blade 25 and the second blade 26 are arranged so as to be shifted in the radial direction. When such a crossflow fan 18 rotates, wind is generated by both the first blade 25 and the second blade 26. When wind is generated by both the first blade 25 and the second blade 26, the wind generated by the first blade 25 and the wind generated by the second blade 26 interfere with each other. When the wind from the first blade 25 and the wind from the second blade 26 interfere with each other, the interfering wind becomes irregular and turbulent. Therefore, the wind generated from the entire crossflow fan 18 can be made irregular, thereby reducing the NZ noise generated due to the rotation of the crossflow fan 18. The NZ noise is a noise generated with a frequency determined by the rotation speed and number of blades of the crossflow fan 18.

In this embodiment, the first blade 25 and the second blade 26 are arranged so that the first virtual line (dashed line r1 or dashed line R1 in FIG. 3) connecting the first blade 25 and the rotation axis C and the second virtual line (dashed line r2 or dashed line R2 in FIG. 3) connecting the second blade 26 and the rotation axis C are in different directions. That is, the first blade 25 and the second blade 26 are arranged so that their positions are shifted in the circumferential direction. In other words, the first blade 25 and the second blade 26 are arranged so that the first blade 25 and the second blade 26 do not overlap when viewed radially outward from the rotation axis C, and a gap is generated between the first blade 25 and the second blade 26. As a result, wind passes between the first blade 25 and the second blade 26. Therefore, the wind generated by the first blade 25 and the wind generated by the second blade 26 are more likely to interfere with each other. Therefore, the wind generated by the entire crossflow fan 18 can be made irregular, which reduces the NZ noise caused by the rotation of the crossflow fan 18.

In this embodiment, the number of first blades 25 and the number of second blades 26 are different. As a result, when the first blades 25 and the second blades 26 are arranged in a row around the rotation axis C, the circumferential positions of the first blades 25 and the second blades 26 are shifted. That is, when viewed radially outward from the rotation axis C, a gap is generated between the first blades 25 and the second blades 26. In addition, since the number of first blades 25 and the number of second blades 26 are different, the length (circumferential length) of each gap is different. Wind that passes through gaps of different lengths has different vectors after passing through. Therefore, the regularity of the vector is reduced, so that the wind generated from the entire crossflow fan 18 can be made irregular.

In this embodiment, the number of second blades 26 provided on the radially inner side is fewer than the number of first blades 25 provided on the radially outer side. That is, the first blades 25 with a larger number are arranged around the rotation axis C on the outer peripheral portion with a larger area, and the second blades 26 with a smaller number are arranged around the rotation axis C on the inner peripheral portion with a smaller area. This makes it possible to increase the distance between adjacent first blades 25 and second blades. This makes it possible to prevent the first blades 25 and second blades 25 from being too close to each other and from being unable to blow air properly.

In this embodiment, the wind generated by the crossflow fan 18 is irregular as described above, and is therefore close to natural wind. In this way, since the wind generated by the crossflow fan 18 can be made to be close to natural wind, even if the user directly receives the wind supplied from the indoor unit 1 to the room, the sensation of the user receiving the wind from the indoor unit 1 can be made to be close to the sensation of receiving natural wind. This can improve the comfort of the user.

The present invention is not limited to the above embodiment, and can be modified as appropriate without departing from the spirit of the invention.

For example, in the above embodiment, the first blade 25 and the second blade 26 are formed so that the distance r1 between the inner end 25a of the first blade 25 and the rotation axis C is longer than the distance r2 between the inner end 26a of the second blade 26 and the rotation axis C, but the present invention is not limited to this. The first blade 25 and the second blade 26 may be arranged so that the distance R1 between the outer end 25b of the first blade 25 and the rotation axis C is longer than the distance R2 between the outer end 26b of the second blade 26 and the rotation axis C, and for example, the distance r1 between the inner end 25a of the first blade 25 and the rotation axis C and the distance r2 between the inner end 26a of the second blade 26 and the rotation axis C may be the same length. In other words, r1 = r2.

In addition, in the above embodiment, an example has been described in which the multiple first blades 25 are arranged at equal pitches in the circumferential direction, but the present invention is not limited to this. The multiple first blades 25 may also be arranged at unequal pitches in the circumferential direction. Furthermore, the multiple second blades 26 may also be arranged at unequal pitches in the circumferential direction. By arranging the first blades 25 and/or second blades 26 at unequal pitches in this manner, the wind generated by the blades arranged at unequal pitches can be made more irregular, and NZ noise can be further suppressed.

The plate thickness of the first blade 25 and the plate thickness of the second blade 26 may be different. By configuring it in this way, the wind vector generated by the first blade 25 and the wind vector generated by the second blade 26 can be different vectors, so the wind generated from the entire crossflow fan can be made more irregular, and NZ noise can be further suppressed.

The curvature of the first blade 25 and the curvature of the second blade 26 may be different. By configuring in this way, the wind vector generated by the first blade 25 and the wind vector generated by the second blade 26 can be different vectors, so the wind generated from the entire crossflow fan can be made more irregular, thereby further suppressing NZ noise.

In addition, in the above embodiment, the number of first blades 25 and the number of second blades 26 are different, but the present invention is not limited to this. For example, the number of first blades 25 and the number of second blades 26 may be the same. In addition, the number of first blades 25 and the number of second blades 26 are not limited to the example described in the above embodiment.

1: Indoor unit 2: Housing 3: Base 4: Front panel 5: Front opening 6: Intake panel 7: Outlet grill 8: Rear drain pan 9: Air flow path wall 10: Refrigerant pipes 11: Pipe housing 12: Intake grill 13: Intake port 14: Outlet port 15: Air filter 16: Air purification filter 17: Indoor heat exchanger 17A: First heat exchanger 17B: Second heat exchanger 17C: Tube 17D: Fin 18: Cross flow fan 19: Stabilizer 20: Ventilation path 20A: Outlet flow path 21: Front drain pan 22: Vertical louver 23: Horizontal flap 24: Bracket 25: First blade 25a: Inner end 25b: Outer end 26: Second blade 26a: Inner end 26b: Outer end C: Rotation axis

Claims (5)

A crossflow fan having a cylindrical outer shape formed by arranging a plurality of blades in an annular manner around a rotation axis, and blowing out a fluid introduced into the fan to the outside by rotating around the rotation axis,
the plurality of blades include a plurality of first blades that are curved in a cross section cut along a plane perpendicular to the rotation axis, and a plurality of second blades that are arranged on the inner circumferential side of the first blades and are curved in the cross section,
the first blade and the second blade are arranged such that, in a plane perpendicular to the rotation axis, r1 is a distance between an inner end of the first blade and the rotation axis, r2 is a distance between an inner end of the second blade and the rotation axis, R1 is a distance between an outer end of the first blade and the rotation axis, and R2 is a distance between the outer end of the second blade and the rotation axis, r2≦r1 and R2<R1;
The first blades are arranged at uneven pitches in the circumferential direction,
The second blades are arranged at an uneven pitch in the circumferential direction,
A crossflow fan, wherein a curvature of the first blade and a curvature of the second blade are different from each other. The crossflow fan according to claim 1, wherein the first blade and the second blade are arranged such that a first virtual line connecting the first blade and the rotation axis and a second virtual line connecting the second blade and the rotation axis are in different directions. The first blade is arranged in a plurality of pieces around the rotation axis,
The second blades are arranged in a row around the rotation axis,
3. The crossflow fan according to claim 1, wherein the number of the first blades is different from the number of the second blades. The crossflow fan of claim 3, wherein the number of the first blades is greater than the number of the second blades. An indoor unit of an air conditioner equipped with a crossflow fan according to any one of claims 1 to 4.

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