JPH0697102B2 - Air conditioner - Google Patents

Description

TECHNICAL FIELD The present invention relates to an air conditioner that reduces rotational noise of a cross flow fan.

<Prior Art> Conventionally, there is an indoor unit of an air conditioner as shown in Fig. 7 (Japanese Utility Model Publication No. 61-79115). In this indoor unit, by rotating the cross flow fan 2, the air sucked from the room is heat-exchanged by the indoor heat exchanger 1, and then blown out into the room again from the air outlet 3.

By the way, recently, decorativeness is also desired for an indoor unit of an air conditioner, and as a result, it has been desired to reduce the thickness of the indoor unit.

<Problems to be Solved by the Invention> However, in the above conventional air conditioner, if the thickness of the indoor unit is made thin, the distance between the indoor heat exchanger 1 and the rotating end of the cross flow fan 2 must be shortened. However, there is a problem that the rotation noise due to the cross flow fan 2 is increased. This is because when the distance between the indoor heat exchanger 1 and the rotating end of the cross flow fan 2 is narrowed, the vortex generated near the stabilizer 4 becomes stronger, and the wind pressure generated when the blades of the cross flow fan 2 cut the vortex. It is considered that this is because the pulsation becomes large.

Therefore, it is conceivable to cut out the rear edge portion of the fin in the indoor heat exchanger 1 that is closest to the crossflow fan to secure the distance between the fin and the rotating end of the crossflow fan 2. However, even if the fins are cut out and a certain distance can be secured between the fins and the rotating end of the cross flow fan 2, the wind flowing between the fins of the indoor heat exchanger 1 is a strong laminar flow, and therefore the vicinity of the stabilizer 4 The vortex that is generated in is still a strong vortex. Therefore, it is not so effective in reducing the rotational noise.

Therefore, an object of the present invention is to provide an air conditioner that can reduce the rotation noise of a crossflow fan even if the indoor unit is made thin.

<Means for Solving the Problems> In order to achieve the above object, the present invention, as illustrated in FIG. 1, has an indoor heat exchanger in the vicinity of the upstream side of the crossflow fan 11 in parallel with the crossflow fan 11. 13 is arranged so that the indoor air sucked through the front grill 12 by the rotation of the cross flow fan 11 is transferred to the indoor heat exchanger.
In an air conditioner having an indoor unit that heat-exchanges by 13 and then sends out indoors from an outlet 16, said indoor heat exchanger
It is characterized in that the leeward side rear edge portion 15a of the plurality of fins 15 arranged in parallel between the 13 tube plates and closest to the cross flow fan 11 is bent with respect to the fin surface.

<Operation> When the cross-flow fan 11 rotates, the indoor air is sucked in through the front grill 12 and heat-exchanged by the indoor heat exchanger 13, and then blown out into the room from the air outlet 16. At that time, the air passing through the leeward side trailing edge portion 15a of the fins 15 of the indoor heat exchanger 13 closest to the crossflow fan 11 is slightly disturbed by the bent portion of the fin surface, so that the indoor heat The vortex generated between the exchanger 13 and the cross flow fan 11 is weakened. Therefore, the rotation noise generated by the rotation of the cross flow fan 11 is reduced.

<Example> Hereinafter, the present invention will be described in detail with reference to illustrated examples.

Fig. 2 shows the secondary sound (frequency Nz × 2 component, where N is the cross-flow fan speed, z is the number of cross-flow fan blades) in the rotational noise radiated from the indoor unit of the air conditioner. The pattern is shown. It can be seen from FIG. 2 that the secondary sound is radiated around the shortest distance region between the indoor heat exchanger of the indoor unit and the fan. Also, from FIG. 3, this 2
It can be seen that the region where the next sound is emitted is the intermediate region where the wind speed decreases. Therefore, the present invention reduces the power of rotational noise by positively disturbing the wind flow in the intermediate region, which is less affected even if the wind flow is slightly disturbed due to the low wind speed.

FIG. 1 is a sectional view of an indoor unit according to the present invention. By rotating the cross flow fan 11, the front grill 12
The room air that has been sucked in after passing through passes through the refrigerant tubes 14, 14, ... Of the indoor heat exchanger 13 and reaches the cross flow fan 11. Then, by the rotation of the cross flow fan 11, the cross flow fan 11 passes through the air outlet 16 and is blown out into the room. In that case, the blowing direction is determined by the vertical blades 17 and the horizontal blades 18.

At that time, a vortex occurs between the stabilizer 20 and the cross flow fan 11 provided at the tip of the drain pan 19. When the blades of the cross flow fan 11 cut the generated vortices, the wind pressure pulsates and rotational noise is generated. Therefore, if the strength of the generated vortex is weakened, the pulsation of the wind pressure is also reduced and the rotation noise can be reduced.

Therefore, in this embodiment, the leeward side trailing edge portion 15a closest to the cross flow fan 11 in the plurality of fins 15 juxtaposed between the tube sheets (not shown) of the indoor heat exchanger 13 has a trailing edge shape of substantially the same. It is crushed into an arc shape. By doing so, the crushed fins are spread to the left and right at the trailing edge portion 15a of the fin 15 as shown in FIG. 1 (b). Therefore, a small turbulence will be generated in the air flow passing through the crushed portion 15a of the fin 15 along the fin surface, and the strength of the vortex generated between the stabilizer 20 and the crossflow fan 11 will be weakened. is there.
Therefore, the pulsation of the wind pressure generated by the blades of the cross flow fan 11 cutting the vortex is also small, and the rotation noise is also small. That is, even if the indoor unit is made thin, the rotation noise does not increase.

At this time, resistance is generated in the air passing through the rear edges 15a of the fins 15 of the indoor heat exchanger 13, so that the amount of air blown out by the cross flow fan 11 decreases to some extent. However, since the air volume has already dropped in the intermediate region as described above, the air volume does not drop significantly. At the same time, since the strength of the vortex generated near the stabilizer 20 becomes weaker and the air volume passing through the cross flow fan 11 increases, the decrease and increase of the air volume are offset, and the overall air volume is kept substantially constant. It is done.

FIG. 4 (a) is a frequency characteristic of the sound pressure level of the rotation noise from the indoor unit according to the present embodiment, and FIG. 4 (b) is a frequency characteristic of the sound pressure level of the rotation noise from the indoor unit in the conventional example. It is a characteristic. Further, FIG. 5 is an air volume characteristic of the sound pressure level of the rotation noise from the indoor unit according to the present embodiment. From FIGS. 4 and 5, it can be seen that the sound pressure level is reduced only in the portion of the rotational noise corresponding to the secondary sound. That is, this example has been proved to be effective as a measure against secondary noise reduction of rotational noise. Further, FIG. 6 is a diagram comparing the amount of air blown from the crossflow fan 11 in this embodiment with the amount of air blown from the crossflow fan 1 in the conventional example. As shown in FIG. 6, in this embodiment, there is almost no decrease in the air volume compared to the conventional example.

Thus, in this embodiment, the indoor heat exchanger 13 is arranged in parallel in the vicinity of the upstream side of the cross flow fan 11 in the indoor unit. Then, the portion 15a closest to the rotating end of the cross flow fan 11 in the rear edge portion of the fin 15 of the indoor heat exchanger 13 is crushed, and the rear edge portion 15a of the fin 15 is widened to the left and right with respect to the fin surface. Of. By doing so, a small turbulence is generated in the air flow passing through the rear end edge 15a of the fin 15 along the fin surface, and the strength of the vortex generated between the stabilizer 20 and the cross flow fan 11 is weakened. Therefore, the pulsation of the wind pressure generated by the blades of the cross flow fan 11 cutting the vortex is reduced, and the rotation noise is reduced. That is, according to the present embodiment, it is possible to create a thin indoor unit with low rotational noise.

In the above embodiment, the fin 15 cross flow fan
Although the rear edge 15a closest to the rotation end of 11 is crushed, the rear edge 15a of the fin 15 is bent with respect to the fin surface, but it may be bent by an appropriate method regardless of crushing. You may

<Effects of the Invention> As is clear from the above, in the indoor unit of the air conditioner of the present invention, the leeward side rear edge portion closest to the cross flow fan of the fins of the indoor heat exchanger is bent with respect to the fin surface. Therefore, even when the indoor unit is made thin, the strength of the vortex generated between the indoor heat exchanger and the cross flow fan can be weakened, and the rotation noise of the cross flow fan can be reduced.

[Brief description of drawings]

FIG. 1 (a) is a sectional view of an embodiment of an indoor unit according to the air conditioner of the present invention, FIG. 1 (b) is an enlarged perspective view of part A in FIG. 1 (a), and FIG. FIG. 3 is a diagram showing a radiation direction of a secondary sound in noise, FIG. 3 is a diagram showing an intermediate region, FIG. 4 is a diagram showing frequency characteristics of sound pressure level in this embodiment and a conventional example, and FIG. 5 is this embodiment. FIG. 6 is a sound pressure level air volume characteristic diagram in the related art, FIG. 6 is a diagram showing the air volume rotation speed characteristic in the present embodiment and the conventional example, and FIG. 7 is a sectional view of a conventional indoor unit. 11 …… Cross flow fan, 13 …… Indoor heat exchanger, 15 …… Fin, 16 …… Blowout port, 20 …… Stabilizer.

Claims (1)

[Claims] 1. An indoor heat exchanger (13) is arranged in the vicinity of an upstream side of the cross flow fan (11) in parallel with the cross flow fan (11) and the front surface is rotated by the rotation of the cross flow fan (11). After the indoor air sucked through the grill (12) is heat-exchanged by the indoor heat exchanger (13),
In an air conditioner having an indoor unit that discharges indoors from a blowout port (16), the crossflow fan (11) of a plurality of fins (15) arranged in parallel between the tube plates of the indoor heat exchanger (13) An air conditioner characterized in that the closest leeward rear edge (15a) is bent with respect to the fin surface.