JPS6237967Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an improvement in the soundproof structure of a reciprocating compressor.

For example, a reciprocating compressor used in a package air conditioner has a compressor main body housed in a container having an oval shape in plan. This compressor is installed in a machine room together with a condenser or the like, or it is installed surrounded by a soundproof box.

By the way, since this type of compressor has a gap between the compressor body and the container, air column resonance is likely to occur during operation. Particularly in the case of a type that is placed directly in a machine room, if the machine room dimensions are equal to λ/2 (λ: wavelength) of the resonant frequency of the compressor, the resonance is further amplified in the machine room. In reality, if the width (horizontal) dimension of the machine room is approximately twice the long axis dimension of the elliptical container of the compressor, the resonance amplification phenomenon described above becomes large. However, the current situation is that most products related to the above-mentioned dimensions are provided.

The present invention was developed in view of the above circumstances, and its purpose is to reduce operating noise by setting the soundproofing body dimensions to the length of 1/4 wavelength of the air column resonance frequency of the compressor. The aim is to provide a soundproof structure for a compressor that can reduce noise.

An embodiment of the present invention will be described below based on the drawings. In the figure, 1 is the main body of the package air conditioner. A suction port 2 is provided at the center of the front surface of the main body 1, and an outlet port 3 is provided at the top thereof. Inside is partition plate 4
It is divided into upper and lower parts, and a heat exchanger 5 and a blower 6 are arranged in the upper part, and a plenum room 7 is provided. A machine room 10 is provided below the partition plate 4 in which a compressor 8 having dimensions to be described later and a soundproof box 9 that is a soundproof body surrounding the compressor 8 are arranged.

Here, the compressor 8 is of a reciprocating type in which a compressor main body 8a is housed in a planar container 11, and the radius R ₁ of the compressor main body 8a, the long axis dimension a of the container 11, and the short axis dimension b Then, the average radius R ₂ of the container 11 is obtained by a+b/4. The resonant frequency of the compressor 8 is theoretically determined from the above conditions, and the results shown in FIG. 2 are obtained.

For example, when a=26cm, b=21cm, and _R1 =8.5cm, _R226 +21/4≈11.8cm. Applying this value to FIG. 2, the radius ratio R ₁ /R ₂ is 8.5/11.
Since 8=0.72, the resonance frequency is approximately 230Hz in the height direction,
It turns out that it is about 290 Hz in the radial direction and about 340 Hz in the mixture of the height direction and the radial direction.

The soundproof box 9 also has a resonant frequency, which has width (horizontal) dimension A, depth (vertical) dimension B, and height dimension C.
When this is done, the results shown in FIG. 3 are obtained. Conventional soundproof boxes are installed along the solid line λ/2 (λ: wavelength) curve, and the actual dimensions are A = 58 cm, B = 24 cm.
cm, C=48cm. It is clear from the figure that the resonance frequencies in each direction are approximately 290 Hz in the A direction, approximately 600 Hz in the B direction, and approximately 360 Hz in the C direction.

Therefore, the mixed resonance frequency in the radial direction, height direction, and radial direction of the compressor 8 substantially matches the resonance frequency in the width direction and height direction of the soundproof box, and the sound is amplified by the soundproof box. The Rukoto. 1m away from a package air conditioner with this type of structure, and 1.5m in height.
Figure 4 shows the noise measurement results at the measurement points.
The power supply frequency was 60Hz, the blower was set to low wind, and other JIS standard conditions were used.

Therefore, the dimensions of the soundproof box 9 are set along a curve of λ/4 (λ: wavelength) as shown by the broken line in FIG.
For example, let A=32cm, B=24cm, and C=40cm.
The resonance frequency in each direction from the dashed curve is approximately
220Hz, about 250Hz, about 340Hz. Therefore, the sound radiated from the compressor 1 can be almost completely canceled. FIG. 5 shows the noise measurement results for a packaged air conditioner equipped with the soundproof box 9 of the above dimensions, and the measurement conditions are the same as those shown in FIG. 4.
It is found that the noise peak shape is lower in the portion indicated by arrow A in FIG. 4, as shown by arrow B in FIG.

In the above embodiment, the compressor 8 is surrounded by the soundproof box 9, but the present invention is not limited to this, and the compressor 8 may be placed directly in the machine room 10. However, the dimensions of the machine room 10 need to be λ/4 of the resonant frequency of the compressor 8 or an odd multiple of λ/4.

As explained above, according to the present invention, the vertical, horizontal, and height dimensions of the sound insulating body that houses the compressor are each 1/4 wavelength of the air column resonance frequency of the compressor. This has the effect that operating noise can be reduced simply by setting the dimensions of the soundproof body without changing the structure.

[Brief explanation of drawings]

FIG. 1A is a schematic longitudinal cross-sectional view of a packaged air conditioner showing an embodiment of the present invention, FIG. 1B is a cross-sectional plan view of the soundproof structure of the compressor, and FIG. 2 is a resonant frequency of the compressor. Figure 3 is a characteristic diagram of the resonant frequency of the soundproofing body, Figure 4 is a noise measurement diagram of a package air conditioner using a conventional soundproofing body, and Figure 5 is a characteristic diagram of the resonance frequency of the soundproofing body. Fig. 3 is a noise measurement diagram of a packaged air conditioner. 8...Compressor, 9...Soundproof body (soundproof box).

Claims (1)

[Scope of utility model registration request] A soundproof structure for a compressor, characterized in that the vertical, horizontal and height dimensions of a soundproof body housing the compressor are each a quarter wavelength of the air column resonance frequency of the compressor.