JP2019132820A - Anechoic chamber - Google Patents

Abstract

To provide an anechoic chamber capable of suppressing the reduction of sound absorbency and durability of the anechoic chamber even when the moisture of the anechoic chamber is easily condensed.SOLUTION: An anechoic chamber includes a sound absorption layer 15 consisting of a glass wool 15a having water repellency and a co-run cloth 15b provided in the inside of the glass wool 15a having water repellency. Since the sound absorption layer 15 is formed by sequentially laminating the co-run cloth 15b and the glass wool 15a in this order from the inside, the co-run cloth 15b can prevent moisture in the anechoic chamber from permeating into the glass wool 15a even when performing a sound test on high temperature and high humidity conditions after performing the sound test on low temperature conditions, and since the moisture absorption of the glass wool 15a is suppressed, the reduction of the sound absorbency and durability due to the moisture absorption of the glass wool 15a can be suppressed.SELECTED DRAWING: Figure 4

Description

  The present invention relates to an anechoic chamber used for acoustic experiments, noise measurement, and the like.

  An anechoic chamber having a sound insulation layer for insulating the outside is used when performing an acoustic experiment or noise measurement of a measurement object (see, for example, Patent Document 1).

  Patent Document 1 discloses an anechoic chamber in which a sound absorbing panel including a sound absorbing material (glass wool) is attached to a room without a gap.

JP 2008-2981 A

  By the way, when an acoustic test is performed under a high temperature and high humidity condition after an acoustic test is performed under a low temperature condition, moisture in the air is condensed on the surface covering material covering the sound absorbing material, and further, the internal sound absorbing material absorbs moisture, There was a problem that the sound absorbing property and durability of the sound absorbing material may be lowered.

  Therefore, even when moisture in the anechoic chamber is likely to condense, there arises a technical problem to be solved that suppresses a decrease in sound absorption and durability of the anechoic chamber. The purpose is to solve the problem.

  In order to achieve the above object, an anechoic chamber according to the present invention is an anechoic chamber having a sound absorbing layer attached to an inner surface, and the sound absorbing layer includes a sound absorbing material having water repellency, and an inner side of the sound absorbing material. And a surface covering material having water repellency provided so as to cover the sound absorbing material.

  According to this configuration, the sound absorbing layer is configured by laminating the surface covering material and the sound absorbing material in this order from the inside, so that the acoustic test is performed under the high temperature and high humidity condition after the acoustic test is performed under the low temperature condition. Even if it exists, the surface covering material can suppress the moisture in the anechoic chamber from penetrating into the sound absorbing material, and can further suppress the moisture absorption of the sound absorbing material itself.

  The anechoic chamber according to the present invention performs an acoustic test under a first condition in which temperature and humidity are arbitrarily set and a second condition in which the dew point temperature is set to be equal to or higher than the temperature in the first condition. It is preferable to implement.

  According to this configuration, when the acoustic test is performed under the second condition following the first condition, the moisture in the anechoic chamber is likely to condense, but the surface covering material penetrates into the sound absorbing material in the anechoic chamber. To suppress the moisture absorption of the sound absorbing material itself.

  The anechoic chamber according to the present invention is preferably subjected to an acoustic test under a first condition where the temperature is set below the freezing point and a second condition where the temperature is set below the freezing point.

  According to this configuration, when the acoustic test is performed under the second condition following the first condition, the sound absorbing material absorbs moisture when the acoustic test is performed under a high temperature and high humidity condition, and then the moisture absorption is performed when the acoustic test is performed below freezing point. When the water content is frozen and the sound absorbing performance of the sound absorbing material is lowered, the surface covering material can suppress the moisture in the anechoic chamber from penetrating into the sound absorbing material, and can further suppress the moisture absorption of the sound absorbing material itself.

  In the present invention, the sound absorbing layer is configured by laminating the surface covering material and the sound absorbing material in this order from the inside, so that the surface covering material prevents moisture in the anechoic chamber from penetrating into the sound absorbing material, and the sound absorbing layer. Since the moisture absorption of the material itself is suppressed, it is possible to suppress a decrease in sound absorption and durability due to the moisture absorption of the sound absorbing material.

The schematic diagram which shows the anechoic room and air conditioner which concern on one Embodiment of this invention. The front view which shows an air conditioner typically. The longitudinal section which shows the structure of an anechoic room typically. The expanded sectional view which shows the corner | angular part of an anechoic chamber. The I section enlarged view in FIG.

  Embodiments of the present invention will be described with reference to the drawings. In the following, when referring to the number, numerical value, quantity, range, etc. of the constituent elements, it is limited to the specific number unless otherwise specified and clearly limited to the specific number in principle. It may be more than a specific number or less.

  In addition, when referring to the shapes and positional relationships of components, etc., those that are substantially similar to or similar to the shapes, etc., unless otherwise specified or otherwise considered in principle to be apparent. Including.

  In addition, the drawings may be exaggerated by enlarging characteristic portions in order to make the features easy to understand, and the dimensional ratios and the like of the constituent elements are not always the same. In the cross-sectional view, hatching of some components may be omitted in order to facilitate understanding of the cross-sectional structure of the components. In this embodiment, expressions indicating directions such as up and down and left and right are not absolute, and are appropriate when each component is in the posture depicted in the drawing, but the posture has changed. In some cases, it should be interpreted according to changes in posture.

  FIG. 1 is a schematic diagram showing the structure of the anechoic chamber 1 and the air conditioner 3. FIG. 2 is a front view schematically showing the air conditioner 3. In FIG. 2, the main configuration is indicated by a solid line in order to easily understand the internal structure of the air conditioner 3.

  The anechoic chamber 1 is used for an acoustic experiment or noise measurement of the measurement object 2. The measurement object 2 is, for example, an automobile, a motorcycle, an aircraft, or the like. The anechoic chamber 1 is a low-temperature anechoic chamber, and the air conditioner 3 can perform experiments and measurements at a desired temperature. The temperature range that can be handled by the anechoic chamber 1 is set to, for example, -25 ° C to 50 ° C. The humidity range that can be handled by the anechoic chamber 1 is set to 80% or less, for example. The anechoic chamber 1 can continuously perform acoustic tests under different temperature and humidity conditions. For example, after performing an acoustic test under the first condition in which the temperature and humidity are arbitrarily set, The acoustic test can be performed under the second condition in which the dew point temperature is set to be equal to or higher than the temperature at. The first condition is set to a low temperature condition, for example, a temperature of −20 ° C., and the second condition is set to a high temperature and high humidity condition, for example, a temperature of 50 ° C. and a humidity of 80%.

  The air conditioner 3 includes a duct 31, a casing 32, a fan 33, and a coil 34. The air conditioner 3 is a so-called push-type air conditioner in which the fan 33 is arranged on the upstream side of the coil 34 with respect to the air flow direction A. 1 and 2 indicate the air flow direction.

  The duct 31 includes a first duct 31a that connects the return air port 1a of the anechoic chamber 1 and the casing 32, and a second duct 31b that connects the air supply port 1b of the anechoic chamber 1 and the casing 32. I have.

  The first duct 31a may take in outside air as necessary. The first duct 31a is provided with a return air side silencer 35 made of glass wool. In this embodiment, the return air side silencer 35 is provided in three stages along the air flow direction A.

  The second duct 31b is provided with an air supply side silencer 36 made of glass wool. In the present embodiment, the supply side silencer 36 is provided in four stages along the air flow direction A.

  The casing 32 includes a fan housing chamber 32A and a coil housing chamber 32B. Reference numeral 32C denotes a vibration-proof rubber interposed between the fan housing chamber 32A and the coil housing chamber 32B. Moreover, code | symbol 32D is a drain which drains the water in the casing 32 outside.

  The fan housing chamber 32A is provided with an inlet opening 32a connected to the first duct 31a and a communication hole 32b communicating with the coil housing chamber 32B.

  The coil housing chamber 32B is provided with an outlet opening 32c connected to the second duct 31b.

  The fan 33 blows the air flowing in from the return air port 1a to the coil housing chamber 32B. The fan 33 is a general air conditioning fan and has a known structure. The air sent from the fan 33 flows into the coil housing chamber 32B through the communication hole 32b formed smaller than the coil housing chamber 32B. Reference numeral 33 a denotes a motor that drives the fan 33.

  The rectifying plate 37 disposed immediately below the communication hole 32b guides the air sent from the fan 33 so as to diffuse into the coil housing chamber 32B. The rectifying plate 37 is disposed obliquely with respect to the vertical direction V so that air diffuses to the lower part of the coil housing chamber 32B. The rectifying plate 37 is provided in the coil housing chamber 32B across the width direction perpendicular to the paper surface of FIG. The current plate 37 is, for example, a punching metal.

  Three coils 34 are arranged so as to overlap in the vertical direction V. The coil 34 is a directly expanded coil. In order to cool air uniformly, the coil 34 is provided so as to cross the coil housing chamber 32B. The coil 34 includes a tube 34a, a refrigerant inlet pipe 34b that supplies the refrigerant to the tube 34a, and a refrigerant outlet pipe 34c that discharges the refrigerant from the header. Two sets of the refrigerant inlet pipe 34b and the refrigerant outlet pipe 34c are provided.

  A heater (reheater) 38 and a steam humidifier 39 are provided behind the coil 34. The heater 38 raises the temperature of the air. Moreover, the steam humidifier 39 supplies the deficient humidity to the reheated air and adjusts it to the optimum humidity.

  The air exhausted from the outlet opening 32c is supplied to the anechoic chamber 1 through the second duct 31b and the air supply port 1b.

  Next, the structure of the anechoic chamber 1 will be described. FIG. 3 is a longitudinal section schematically showing the structure of the anechoic chamber 1. FIG. 4 is an enlarged cross-sectional view showing a corner portion of the anechoic chamber 1. FIG. 5 is an enlarged view of a portion I in FIG.

  The anechoic chamber 1 includes a wall 11 and a ceiling 12 and is provided in the building 4.

  Anti-vibration rubber 42 is provided between the outer peripheral surface of the wall 11 and the column 41 of the building 4. Anti-vibration rubber 44 is provided between the upper surface of the ceiling 12 and the beam 43 of the building 4. Thereby, the vibration of the anechoic chamber 1 is suppressed.

  The wall 11 and the ceiling 12 include a heat insulating panel 13, a sound insulation layer 14, and a sound absorption layer 15.

  The heat insulation panel 13 is provided in order to maintain the inside of the anechoic chamber 1 at a low temperature. The heat insulation panel 13 includes an outer metal plate 13a, an inner metal plate 13b, and a heat insulating material 13c. The heat insulating panel 13 is formed by filling a heat insulating material 13c between the outer metal plate 13a and the inner metal plate 13b without any gap.

  The outer metal plate 13a and the inner metal plate 13b are made of, for example, iron and are formed in a plate shape. The outer metal plate 13a and the inner metal plate 13b are formed with different thicknesses. For example, the outer metal plate 13a is set to a thickness of 0.6 mm, and the inner metal plate 13b is set to a thickness of 0.4 mm. Thereby, each natural frequency of the outer metal plate 13a and the inner metal plate 13b is set to a different value, and resonance of the heat insulating panel 13 is suppressed.

  The material of the heat insulating material 13c may be any material as long as it exhibits heat insulating properties. For example, hard urethane is adopted. The thickness of the heat insulating material 13c is set to 100 mm, for example.

  A nut 17 that can be fastened to the bolt 16 is embedded in the heat insulating material 13c. Further, an insertion hole (not shown) through which the bolt 16 can be inserted is drilled in the inner metal plate 13b. Prior to filling the heat insulating material 13c, the nut 17 is positioned in advance corresponding to the insertion hole and fixed to the inner metal plate 13b. That is, when the bolt 16 is fastened to the nut 17 in the heat insulating panel 13, the tip of the bolt 16 penetrates the heat insulating panel 13 and is not exposed to the outer peripheral surface of the outer metal plate 13 a, so that the sound insulating layer 14 is exposed to the heat insulating panel 13. It is supported by.

  The sound insulation layer 14 is provided inside the heat insulation panel 13. The thickness of the sound insulation layer 14 is, for example, 80 mm. The sound insulation layer 14 includes a base material 14a, a vibration-proof pad 14b, a glass wool 14c, a plaster board 14d, and a moisture-proof sheet 14e.

  The base material 14a is formed by combining LGS (Light Gauge Steel) of 25 upper stages and 20 lower stages in a grid pattern. The base material 14 a is attached to the inside of the heat insulating panel 13 by fixing the upper LGS to the heat insulating panel 13 with the bolts 16.

  The anti-vibration pad 14b is interposed between the inner metal plate 13b and the base material 14a. Specifically, the bolt 16 penetrates the rectangular vibration-proof pad 14b, and the base material 14a is attached to the inner metal plate 13b via the vibration-proof pad 14b.

  The glass wool 14c is filled between the upper LGS of the base material 14a.

  The plaster board 14d is fixed to the lower LGS of the base material 14a in a state where two sheets are stacked.

  The moisture-proof sheet 14e is provided inside the plaster board 14d. The moisture-proof sheet 14e is a polyethylene film, for example. Thereby, since the moisture-proof sheet 14e prevents the intrusion of water vapor from the sound-absorbing layer 15 into the sound-insulating layer 14, excessive moisture in the sound-insulating layer 14 can be suppressed.

  The sound absorbing layer 15 is provided inside the sound insulating layer 14. The thickness of the sound absorbing layer 15 is, for example, 300 mm. The sound absorbing layer 15 includes glass wool 15a filled inside the moisture-proof sheet 14e, and a cordy run cloth 15b that covers the surface of the glass wool 15a.

  The glass wool 15a is glass wool (for example, “Mag Super Yellow” manufactured by Mag Izobale Co., Ltd.) that has been given water repellency in advance. What gave water repellency may be used. In general, the fiber-based sound absorbing material easily absorbs humidity, and the moisture-absorbing sound absorbing material tends to increase in mass and decrease in sound absorption rate. Therefore, it is conceivable that the glass wool 15a is wrapped with a sheet of polyfilm or the like so that it does not come into contact with moisture. However, the sound absorption of the glass wool 15a may not function due to reflection of sound by the sheet. On the other hand, the glass wool 15a having water repellency suppresses the moisture absorption of the glass wool 15a without disturbing the sound absorption.

  The cordy run cloth 15b is provided inside the glass wool 15a. The cordy run cloth 15b is provided with water repellency by a fluororesin treatment or a silicon resin treatment. Thereby, the condensation of the cordy run cloth 15b can be suppressed without impeding the sound permeability.

  Thus, according to the anechoic chamber 1 according to the present embodiment, the sound absorbing layer 15 is laminated in the order of the cordy run cloth 15b and the glass wool 15a from the inside, for example, a low temperature condition of a temperature of −20 ° C. When the acoustic test is performed under the high temperature and high humidity conditions of the temperature 50 ° C. and the humidity 80% after the acoustic test, the cordy run cloth 15b prevents the moisture in the anechoic chamber 1 from penetrating into the glass wool 15a. Furthermore, since the moisture absorption of the glass wool 15a itself is suppressed, it is possible to suppress a decrease in sound absorption and durability due to the moisture absorption of the glass wool 15a.

  Moreover, according to the anechoic chamber 1 which concerns on this embodiment, in the sound absorption layer 15, since it is laminated | stacked in order of the cordy run cloth 15b and the glass wool 15a from the inner side, it is below freezing point, for example, temperature 50 degreeC and humidity 80% After performing the acoustic test under the high temperature and high humidity conditions, when the acoustic test is performed below the freezing point, for example, at a low temperature of −20 ° C., the moisture absorbed below the freezing point after the glass wool 15a absorbs moisture under the high temperature and high humidity conditions. Where there is a possibility that sound absorption and durability may be reduced due to freezing, the cordy run cloth 15b has glass wool because moisture in the anechoic chamber 1 penetrates into the glass wool 15a and further the moisture absorption of the glass wool 15a itself is suppressed. It is possible to suppress a decrease in sound absorption and durability due to moisture absorption of 15a.

  The present invention can be variously modified without departing from the spirit of the present invention, and the present invention naturally extends to the modified ones.

DESCRIPTION OF SYMBOLS 1 ... Anechoic chamber 1a ... Return air port 1b ... Air supply port 11 ... Wall 12 ... Ceiling 13 ... Thermal insulation panel 13a ... Outer metal plate 13b ... Inner metal Plate 13c ... Heat insulation material 14 ... Sound insulation layer 14a ... Base material 14b ... Anti-vibration pad 14c ... Glass wool 14d ... Plaster board 14e ... Moisture-proof sheet 15 ... Sound absorption layer 15a ..Glass wool (sound absorbing material)
15b ... Cody run cloth (surface coating material)
16 ... Bolt 17 ... Nut 2 ... Measurement object 3 ... Air conditioner 31 ... Duct 31a ... First duct 31b ... Second duct 32 ... Casing 32A ... Fan housing chamber 32B ... Coil housing chamber 32C ... Anti-vibration rubber 32D ... Drain 32a ... Inlet opening 32b ... Communication hole 32c ... Outlet opening 33 ... Fan 33a -Motor 34 ... Coil 34a ... Tube 34b ... Refrigerant inlet pipe 34c ... Refrigerant outlet pipe 35 ... Return air side silencer 36 ... Air supply side silencer 37 ... Rectifying plate 38・ ・ ・ Heater 39 ・ ・ ・ Steam humidifier 4 ・ ・ ・ Building 41 ・ ・ ・ Pillar 42 ・ ・ ・ Anti-vibration rubber 43 ・ ・ ・ Beam 44 ・ ・ ・ Hanging anti-vibration rubber

Claims (3)

An anechoic chamber with a sound-absorbing layer on the inside,
The sound absorbing layer is
A sound-absorbing material having water repellency;
A surface covering material having water repellency provided to cover the sound absorbing material inside the sound absorbing material;
An anechoic chamber characterized by comprising.   The acoustic test is performed under a first condition in which temperature and humidity are arbitrarily set and a second condition in which a dew point temperature is set to be equal to or higher than the temperature in the first condition. Anechoic chamber.   The anechoic chamber according to claim 1, wherein the acoustic test is performed under a first condition in which the temperature is set below the freezing point and a second condition in which the temperature is set below the freezing point.