JPH0317049B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to an air conditioner that adjusts indoor temperature to reduce noise from the air conditioner.

[Background technology] Conventionally, fan wind noise or motor noise emitted from the air outlet of an air conditioner was sent directly into the living space on the blowing side by the blower control blades (flaps), which caused problems as noise. However, until now there was no noise suppressor for this type of air conditioner. However, it has been the first noise control device for equipment that is not air conditioners, but is similar to equipment.
The item shown in Figure 2 was found. This is the soundproof cover B for the ventilation fan C, and is attached to the outer wall 11 side to prevent the sound from inside the room from leaking outside through the opening 10 for the ventilation fan C. Structurally, the inner surface 12 is made of glass wool, etc. By attaching sound absorbing material and lengthening the path of sound waves, sound leaking from the room to the outside is absorbed and removed. However, the sound that cannot be absorbed within the soundproof cover B will leak out to the outside in the same direction as the air blowing direction indicated by the arrow in the figure, so this method cannot be said to be very effective for air conditioners. It was hot.

[Object of the Invention] The present invention has been made in view of the above-mentioned points, and its object is to provide an air conditioner that can reduce noise.

[Disclosure of the Invention] Example FIG. 1 shows an example in which the present invention is applied to a wall-mounted air conditioner. The air conditioner A of this embodiment has a suction port 6 at the top of the front surface and an outlet port 7 at the bottom of the front surface. A filter 5 placed behind the suction port 6 sucks air from the
The air is passed through a heat converter 4 to be converted into cold or warm air, and then exhausted from the outlet 7.In order to reduce noise from the fan 3, etc., a refraction controller is installed between the fan 3 and the outlet 7. 1 is provided, and a blower controller 2 is provided at the outlet 7 so that the blowing direction is diagonally downward. The refraction controller 1 is composed of a plurality of flat control elements 1a, each of which is erected in parallel to the surface where the air outlet 7 is formed, and arranged in rows at intervals in the vertical direction and the front-rear direction. death,
The structure is such that the number of arranged elements in the front-rear direction decreases as it goes downward, and the length of the sound path, which is the interval between the control elements 1a arranged in the upper and lower rows, becomes shorter as it goes downward. In other words, when sound passes through the passage, a phase lag occurs. For example, if a plane wave is incident as shown in FIG. 7, the longer the passage, the greater the phase lag. The wavefront (plane connecting points with the same phase) of the sound that has passed is tilted to the illustrated state, and the direction of sound changes (that is, the direction of sound travels changes because the sound travels perpendicular to the wavefront). Therefore, when the refraction controller 1 is installed as shown in FIG. 1, the sound is refracted upward. Note that the air blow controller 2 has a structure in which a plurality of flat air blow control blades 2a are vertically stacked at intervals.

FIG. 4 shows a refraction controller 1 installed in an opening of a sound insulating wall 8 having an opening matching the size of the refraction controller 1.
A measuring device is shown in which sound waves are emitted by a speaker 9 from one side of the sound insulating wall 8, and the sound pressure is measured at the points indicated by the other point. here,
The side where measurements are taken is an anechoic chamber. The distance l ₁ from the measurement side inner wall of the sound insulation wall 8 to the front of the speaker 9 is 170 [cm], the distance l ₂ from the inner wall to the frontmost part of the measurement point is 50 [cm], and the distance from the frontmost part to the rearmost part of the measurement point is 170 [cm]. The distance l ₃ is 80 [cm], and the left and right width of the measurement point l ₄ is 80 [cm].
[cm], and the frequency of the sound wave emitted from the speaker 9 was measured in a 1/3 octave band from 1 KHz to 20 KHz. As for the shape of the refraction controller 1 to be tested, the two types shown in the following table are used for the front and rear spacing l between the control elements 1a, the vertical spacing b' of the control elements 1a, and the vertical width w of the control elements 1a. there was.

w b′ l fc (Hz) Type A 50 20 20 2.4K Type C 50 8.3 20 2.9K Here, the units of the intervals w, b′, and l are millimeters. However, the control element 1a has a plate thickness of 3 mm.
The one is used. Note that the refraction controller 1 also has the characteristics of a so-called low-pass filter that attenuates high frequencies by absorbing sound through its control element 1a, etc., so the cut-off frequency fc is shown in the above table. The reason why the frequency of the sound waves emitted from the speaker 9 is set from 1KHz to 20KHz is as follows.
The results obtained by theoretically calculating the relationship between the refraction angle and the frequency of Type A and Type C are shown in Figure 8. The closer the cutoff frequency fc is, the greater the sound can be refracted, and the cutoff frequency
When it becomes lower than fc and below 1KHz, the refraction angle becomes almost constant. Therefore, when determining the refraction effect of sound, it is sufficient to see up to 1KHz, so the lower limit was set at 1KHz, and the upper limit was set at 20KHz, which is the upper limit audible to the human ear. be. FIG. 6 shows the results of measuring the state of sound refraction by the refraction controller 1 using the above device. Figure 6 is
This shows the case where the sound wave emitted from the speaker 9 is made into a sine wave with a frequency of 2KHz using the Type C refraction controller 1. In the figure, the shaded area indicates the sound pressure is less than 70 dB, and the non-hatched area indicates the sound pressure is 70 dB or more. . As is clear from the figure, the sound pressure is higher on the bottom side of the refraction controller 1, indicating that the sound wave is refracted.

Next, the results of measuring the sound energy attenuation effect of the refraction controller 1 will be shown. In this measurement, a sound wave was applied to the refraction controller 1 in the same manner as explained in Fig. 7, and a specimen with five sound passages as shown in Fig. 9 was used. Since this is a location where the signal can be transmitted well, measurements were taken by placing five microphones at locations corresponding to the respective passages in the vertical direction. Although the sound pressure is considered to be the same in the horizontal direction corresponding to one passage, five microphones are arranged in the horizontal direction corresponding to one passage in order to improve measurement accuracy. Five types of specimen shapes A to E shown in the table below were prepared and measured.

A B C D E w 50 50 50 32.5 32.5 b' 20 20 8.3 20 13.4 l 20 10 20 20 13.1 θ 15.9 8.1 18.9 20.9 15.9 The units of spacing w, b', l are millimeters,
The angle θ is the angle between the tip of the uppermost control element and the tip of the next control element with the vertical direction. FIG. 11 shows the results measured using the above-mentioned measuring device. Note that FIG. 11 shows the amount of reduction in the sound pressure level when the refraction controller 1 is installed compared to the sound pressure level when the refraction controller 1 is not provided. However, FIG. 11 typically shows the case where the amount of decrease in the sound pressure level is determined from the average value of the sound levels collected by three microphones at the horizontal center and on both sides thereof. As is clear from the results of this measurement, an attenuation effect of 10 to 15 db was obtained with and without the refraction controller 1.

In this embodiment, the refraction controller 1 is installed between the fan 3 and the outlet 7 as shown in FIG.
Since the propagation direction of sound is refracted upward, when the air conditioner A is mounted on a wall as shown in Fig. 3, the refraction controller 1 refracts the sound upward, and the air blower controller 2 blows air. By changing the direction and attenuating the sound energy, noise such as motor sound can be effectively reduced.

[Effects of the Invention] As described above, the present invention includes a refraction controller that refracts sound between the fan and the outlet, and
The air outlet is provided with an air blowing control means for controlling the air blowing direction, and a plurality of flat control elements are arranged parallel to the forming surface of the air outlet. The refraction controller is formed in such a structure that the refraction controllers are arranged in rows at intervals in each direction, and the number of rows in the vertical direction decreases as it goes toward the direction in which the airflow is controlled by the airflow control means. Sound can be refracted in a direction different from the direction of air blowing by the air blowing control means, making it difficult for sound to propagate in the direction of air blowing, and noise such as motor noise can be reduced. Furthermore, since the refraction controller having the above-described structure attenuates sound energy, a good noise reduction effect can be expected in combination with the above-described function of making the air blowing direction different from the sound propagation direction.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing one embodiment of the present invention, and FIG.
The figure is an enlarged perspective view with a part of the main part of the same as above cut away, FIG. 3 is an explanatory diagram showing the usage state of the same as above, and FIG. 4 is a measuring device for measuring the characteristics of the first refraction controller as above. Fig. 5 is a perspective view showing the shape of the first refraction controller under test, Fig. 6 is an explanatory diagram showing the measurement results of the same, and Fig. 7 shows how the refraction controller refracts sound. An explanatory diagram of the principle, Figure 8 is a characteristic diagram when the theoretical frequency versus refraction angle of the first refraction controller is calculated, and Figure 9 explains other characteristics of the first refraction controller. A perspective view showing a measurement state for
FIG. 0 is a model diagram showing the first refraction controller under test as above, FIG. 11 is a graph showing the measurement results of same as above, and FIG. 12 is a sectional view showing a conventional example related to the present invention. A is an air conditioner, 1 is a refraction controller, 1a is a control element, 2 is a blower controller, 3 is a fan, and 7 is an outlet.

Claims (1)

[Claims] 1 A refraction controller that refracts sound is provided between the fan and the outlet, and an air blowing control means that controls the direction of air is provided at the outlet, and a plurality of flat control elements are placed on the forming surface of the outlet. They are arranged in parallel to each other, and are arranged in rows at intervals in a direction parallel to and a direction perpendicular to the forming surface of the air outlet, and the number of arranged sheets in the vertical direction is adjusted to the side in which the air blowing control means blows the air. An air conditioner comprising the above-mentioned refraction controller formed in a structure that is reduced in size.