JP4435110B2 - Sound insulation device - Google Patents

Description

  The present invention relates to a sound insulation device that reduces noise from a noise generation source.

Conventionally, a sound insulation wall is known as a sound insulation device for reducing noise from a noise generation source such as an engine or a generator (see Patent Document 1). For example, the sound insulation device 52 of FIG. 7 is configured by a sound insulation wall 70 and is directly placed on the placement surface 30 such as the ground. A sound absorbing member 73 is attached to the inner diameter surface of the sound insulating wall 70 facing the generator 8. According to the sound insulation device 52, noise generated from the generator 8 can be reduced by sound insulation and sound absorption.
Here, when a relatively large generator 8 for a construction machine or construction equipment is operated, hot air is generated along with noise. In the above-described sound insulating device 52, the upper portion of the disposition portion 4 where the generator 8 is disposed is the discharge port 6, and is open to discharge hot air. However, since there is little spontaneous air flow in the arrangement portion 4 as a space in which the generator 8 is arranged, hot air tends to stay inside the arrangement portion 4. For this reason, if the generator 8 is continuously operated in the arrangement unit 4 for a long period of time, the temperature in the arrangement unit 4 is relatively likely to rise, and there is a concern that some adverse effect on the generator 8 may occur.

  As a technique for efficiently discharging hot air in the arrangement unit 4 to the outside, for example, there is a technique described in Patent Document 2. Outside air is always taken in by the fan in the arrangement portion where the engine described in Patent Document 2 is arranged. This outside air causes an air flow (air flow) along the engine in the arrangement portion. Hot air is discharged from the discharge port formed in the lower part of the arrangement portion by this air flow.

Considering the above technique, for example, if an air flow is created in the arrangement portion 4 of the sound insulation device 52, hot air can be efficiently discharged upward. For example, as shown in FIG. 8, a communication hole 74 for taking in outside air is provided in the lower part of the sound insulation wall 70. An outside air can flow from the communication hole 74 into the arrangement portion 4, and an air flow can be formed by pushing the hot air from the generator 8 upward in the vertical direction.
Registered Utility Model No. 3109567 Japanese Patent Laid-Open No. 2004-360641

However, in the sound insulation wall 70 provided with the communication hole 74 described above, the noise of the generator 8 is directly transmitted to the outside from the communication hole 74. Of course, a soundproof plate can be attached in the vicinity of the communication hole 74 (see Patent Document 2), but the inflow of outside air is also blocked by this plate.
The present invention was devised in view of the above points, and an object of the present invention is to allow outside air to flow into the sound insulation device while suppressing transmission of noise from the noise generation source to the outside. It is to form an air flow in the inside.

As a means for solving the above-mentioned problems, the sound insulation device according to the first aspect of the present invention is provided with an arrangement portion where a noise generating source for generating hot air is arranged and a sound absorbing member for absorbing the noise of the noise generating source. An inner sound insulation wall arranged outside the part, an outer sound insulation wall arranged so as to surround the inner sound insulation wall and the arrangement part, and formed vertically above the arrangement part so as to discharge the hot air of the noise generation source and open to the outside air and a discharge port that is, between the inner sound insulating wall and the outer sound insulation wall, to the placement portion outside air introducing passage for introducing outside air is formed, the lower portion of the air introduction passage, from the vertical direction under the arrangement portion It is configured to communicate with the arrangement portion so that an upward air flow is generated, and the upper part of the outside air introduction path is outside the discharge port and from the discharge port so that hot air discharged from the discharge port does not flow in. Is also opened at the lower position in the vertical direction, and the inner sound insulation Together but are disposed so as to surround the placement portion, the sound absorbing member is attached to the surface over the entire surface facing the noise source inside the sound insulating wall, a longitudinal section of the sound absorbing member, having a protruding convex shape toward the noise source It is characterized by.

In the sound insulation device according to the first aspect of the invention, the noise generating source that generates hot air is arranged in the arrangement portion. An inner sound insulation wall and an outer sound insulation wall are arranged outside the arrangement portion. A discharge port for discharging hot air from the noise generation source is formed above the arrangement portion in the vertical direction. Outer sound insulating wall is that is arranged to surround the inner sound insulation wall placement portion. Between the inner side sound insulation wall and the outer sound insulating member outside air introducing passage is formed, the outside air is taken leads to placement portion by the outside air introducing passage.
The lower part of the outside air introduction path is configured to communicate with the arrangement part so that an air flow from the lower side to the upper side in the vertical direction is generated in the arrangement part. For example, the lower part of the outside air introduction path communicates with the arrangement part at a position vertically below the discharge port. It is preferable to communicate at a lower position of the arrangement portion. Outside air in the outside air introduction path flows into the arrangement portion from the lower side in the vertical direction than the discharge port, and hot air in the arrangement portion is discharged from the discharge port to the upper side in the vertical direction. For this reason, an air flow is generated in the arrangement portion from the bottom to the top in the vertical direction.
The upper part of the outside air introduction path is configured to open at a position separated from the discharge port so that hot air discharged from the discharge port does not flow. For example, the upper part of the outside air introduction path opens outside the discharge port for discharging hot air and at a position vertically below the discharge port . Heat care, since it is discharged at a position spaced apart from the top of the outside air introducing path hot air is unlikely to flow into the air introduction passage, the outside air is configured to easily flows.

A sound absorbing member that absorbs noise from the noise generating source is attached to the inner sound insulating wall of the sound insulating device. A double wall made up of an inner sound insulation wall and an outer sound insulation wall is arranged outside the noise generating source arranged in the arrangement portion. An outside air introduction path formed between the outer sound insulation wall and the inner sound insulation wall serves as an air spring. For this reason, the noise generated from the noise source is reduced by the sound insulation effect of the sound absorbing member and the sound insulation effect of the double wall.
Further, the noise of the noise generating source transmitted to the outside from the lower part of the outside air introduction path passes through the outside air introduction path, and in the process of passing through the outside air introduction path, the vibration energy of the noise is attenuated and reduced.

Further, the first invention of the present invention, the inner sound insulating wall is disposed so as to surround the placement portion, the inner sound insulating wall, an upper wall provided for covering the upper side of the placement portion, the discharge port is formed in the upper wall, exhaust The outlet may be provided with a discharge means capable of forcibly discharging the hot air from the noise generation source through the discharge port.
In the sound insulation device according to the first aspect of the invention, the double wall of the inner sound insulation wall and the outer sound insulation wall surrounds the outside of the arrangement portion. The upper part of the arrangement part is covered with an upper wall provided on the inner sound insulation wall. A discharge port is formed in the upper wall. The discharge port has a smaller diameter (opening size) than the inner sound insulation wall. Due to this throttling effect, the vibration energy of the noise of the noise source transmitted from the discharge port upward in the vertical direction is attenuated and reduced.
The discharge port can be provided with discharge means for forcibly discharging the air in the arrangement portion. For this reason, the air flow in the arrangement portion can be relatively maintained.

Further, in the first aspect of the present invention, the sound absorbing member is attached to the surface over the entire surface facing the noise source inside the sound insulating wall, longitudinal section of the sound absorbing member to have a protruding convex shape toward the noise source It is characterized by.
In the sound insulation device according to the first aspect of the present invention, the arrangement portion is narrowed down by the convex sound absorbing member protruding toward the noise generating source. The noise of the noise generating source transmitted through the convex portion of the sound absorbing member and transmitted vertically upward is attenuated and reduced by the diaphragm effect.
Further, the air flow generated in the arrangement portion increases the flow velocity at the convex top of the sound absorbing member and flows upward along the convex sound absorbing member. For this reason, a smoother air flow is formed in the arrangement portion.

According to the sound insulation device of the first invention, it is possible to form an air flow inside the sound insulation device by flowing outside air into the sound insulation device while suppressing the transmission of the noise of the noise generation source to the outside. Further, the air flow can be maintained while further reducing the noise of the noise generation source. In addition, it is possible to form a smoother air flow while further reducing the noise of the noise generation source.

The best mode for carrying out the present invention will be described below with reference to the drawings.
[First embodiment]
FIG. 1 is a perspective view of a sound insulation device according to a first embodiment. FIG. 2 is a longitudinal sectional view of the sound insulation device, and FIG. 3 is a partial longitudinal sectional view of the sound insulation device. The vertical direction in FIG. 2 is the vertical direction, and the horizontal direction in FIG. 2 is the horizontal direction.
The sound insulation device 2 according to the first embodiment includes a double wall (simply composed of an inner sound insulation wall 18 and an outer sound insulation wall 20 that surrounds a generator 8 (an example of a noise generation source) disposed on a mounting surface 30 such as the ground. , Sometimes referred to as sound insulation wall 19). The inner side of the double wall is an arrangement part 4 in which the generator 8 is arranged, and a discharge port 6 is formed at an upper position in the vertical direction of the arrangement part 4 so as to be in an open state.
The generator 8 is a normal generator (maximum output: 20 kW) having outer dimensions of a width dimension of 370 mm, a length dimension of 600 mm, and a height dimension of 450 mm, and hot air is generated around the generator when operating.

The inner sound insulation wall 18 is a cylindrical wall body that surrounds the placement portion 4. In this embodiment, the inner sound insulation wall 18 is configured to block the noise transmission path of the generator 8 over the entire circumference. The outer sound insulation wall 20 is a cylindrical wall body that surrounds the inner sound insulation wall 18 and the placement portion 4.
The height dimension of the sound insulation wall 19 (the inner sound insulation wall 18 and the outer sound insulation wall 20) may be equal to or higher than the height dimension of the generator 8 in the state of being arranged in the arrangement portion 4, and should be 50 mm to 300 mm higher. Is preferred. When the height is less than 50 mm, the noise of the generator 8 is easily transmitted in the horizontal direction around the sound insulation wall 19 (diffracted sound increases). Moreover, if the height dimension of the sound insulation wall 19 is taken more than necessary, the weight of the sound insulation device 2 increases and the handleability becomes inferior.

The inner sound insulation wall 18 is shown with only a plurality of plate-like attachments (for the sake of convenience, reference numerals 17a, 17b, 17c, and 17d attached to the outer sound insulation wall 20 in a state of protruding upward in the vertical direction from the outer sound insulation wall 20. Is attached via). A discharge port 6 is formed by the upper end portion 10 of the inner sound insulating wall 18. Thereby, the discharge port 6 will be formed in the vertical direction upper direction of the arrangement | positioning part 4 in which the generator 8 is arrange | positioned.
Note that the fixtures 17a, 17b, 17c, and 17d have a predetermined distance between the inner diameter surface of the outer sound insulation wall 20 and the outer diameter surface of the inner sound insulation wall 18 so as not to obstruct as much as possible the air flow of the outside air that passes through the outside air introduction path 22 described later. Each of them is arranged.

The inner sound insulation wall 18 is attached with a gap (clearance Cg) between the inner sound insulation wall 20 (see (I) of FIG. 3). Thereby, the outside air introduction path 22 through which the outside air can pass is formed by the outer diameter surface of the inner sound insulation wall 18 and the inner diameter surface of the outer sound insulation wall 20.
The width dimension (clearance Cg) of the outside air introduction path 22 can be appropriately set depending on the noise generation source. By setting the width dimension of the outside air introduction path 22 to 5 mm to 150 mm, it is possible to allow the outside air sufficient to discharge the hot air from the generator 8 to flow into the placement unit 4. If the width dimension of the outside air introduction path 22 is less than 5 mm, the opening dimension of the upper portion 14 of the outside air introduction path 22 that takes in outside air becomes small, and smooth inflow of outside air may not be achieved. Moreover, although the width dimension of the outside air introduction path 22 may be made larger than 150 mm, the amount of outside air flowing in does not increase extremely. If the width of the outside air introduction path 22 is made larger than necessary, the size of the outer sound insulation wall 20 becomes larger, and the handling of the sound insulation device 2 becomes inconvenient accordingly. In order to ensure easy and smooth inflow of outside air, the sound insulation device 2 is preferably 30 to 100 mm in width.

The inner sound insulating wall 18 is attached with a clearance Cr between the lower end portion 28 and the mounting surface 30 facing the inner sound insulating wall 18 (see (I) in FIG. 3). As a result, a communication hole 32 is formed between the lower end portion 28 of the inner sound insulating wall 18 and the mounting surface 30 facing it, and the lower portion 26 of the outside air introduction path 22 and the lower portion of the arrangement portion 4 are brought into a communication state.
The width dimension (clearance Cr) of the communication hole 32 can be appropriately set corresponding to the width dimension (clearance Cg) of the outside air introduction path 22. For example, the width dimension of the outside air introduction path 22 and the width dimension of the communication hole 32 are made the same, or the width dimension of the communication hole 32 is made larger to ensure the width dimension of the communication hole 32. This is preferable because the outside air smoothly flows from the outside air introduction path 22 into the arrangement portion 4 through the communication hole 32.

The upper portion 14 of the outside air introduction path 22 is formed by the upper end portion 16 of the outer sound insulation wall 20 and the outer diameter surface 12 of the inner sound insulation wall 18 facing it. The upper end portion 16 of the outer sound insulating wall 20 is positioned below the upper end portion 10 of the inner sound insulating wall 18 in the vertical direction. For this reason, the upper part 14 of the outside air introduction path 22 is in a state opened to a position vertically below the above-described discharge port 6, and at a position separated from the discharge port 6 so that hot air discharged from the discharge port 6 does not flow. It will open.
Here, the upper portion 14 of the outside air introduction path 22 is preferably provided 5 mm to 150 mm vertically below the discharge port 6 so that hot air discharged upward from the discharge port 6 does not flow in.
Note that “the hot air discharged from the discharge port 6 does not flow in” means that the hot air hardly flows in, or a level (a small amount) that does not adversely affect the cooling action of the generator 8 by the air flow. This includes the case where the hot air flows in.

The placement portion 4 is formed inside the inner diameter surface 9 of the inner sound insulation wall 18. A porous member 24 (an example of a sound absorbing member) is bonded and fixed to the inner diameter surface 9 of the inner sound insulating wall 18 over the entire surface. The longitudinal cross section of the porous member 24 has an arc shape protruding toward the generator 8. The central portion 24b of the porous member 24 has the largest thickness when viewed in the longitudinal section, and has an arc shape that draws a gentle curve so that the thickness decreases toward the both end portions 24a and 24c. The thickness (central portion 24b thickness) in the central portion 24b of the porous member 24 is appropriately set depending on the maximum output of the noise generating source. For example, in the case of the generator 8, it is 30 to 100 mm from the viewpoint of securing practical sound absorbing performance. And preferred. And from the viewpoint of providing a difference between the thickness of the central portion 24b and the thickness of both end portions 24a, 24c to realize the drawing effect by the porous member 24, it is desirable to set both end portions 24a, 24c to 0-10 mm.
The dimensions of the placement unit 4 are appropriately set according to the external dimensions or maximum output of the stored noise generation source. From the viewpoint of securing the air flow in the arrangement portion 4, it is preferable to provide a predetermined clearance between the central portion 24b of the porous member 24 and the noise generation source. For example, when the generator 8 is housed, the clearance between the central portion 24b of the porous member 24 and the generator 8 is preferably 10 mm to 200 mm.

(I) of FIG. 3 is a partial longitudinal sectional view of the sound insulating device for explaining the air flow. In the figure, the direction of air flow is indicated by a thick arrow.
When the generator 8 is driven, hot air is generated from the generator 8. The hot air is discharged from the discharge port 6 by a vertically upward air flow (updraft), and accordingly, the outside air in the outside air introduction path 22 flows into the placement portion 4 from below through the communication hole 32. At this time, the outside air smoothly flows from the end 24a of the porous member 24 along the arc shape of the central portion 24b. The air flow formed by the outside air flowing into the arrangement portion 4 increases its speed at the central portion 24b of the narrowed porous member 24 (the top of the convex shape of the sound absorbing member), and the central portion 24b of the porous member 24. To the upper discharge port 6 along the arc shape of the end 24c of the porous member 24. For this reason, a smoother air flow is formed in the arrangement portion 4. For this reason, an air flow is generated in the arrangement part 4 from the lower side to the upper side in the vertical direction, and the hot air and the outside air in the arrangement part 4 are smoothly ventilated.
The communication hole 32 for introducing outside air from the outside air introduction path 22 is formed in the entire periphery of the lower end portion 28 of the inner sound insulating wall 18. For this reason, the outside air that has passed through the outside air introduction path 22 flows into the placement portion 4 from the entire periphery of the lower end portion 28 of the inner sound insulation wall 18. The inner sound insulation wall 18 is cylindrical. By arranging the generator 8 in the center of the arrangement part 4, the outside air that has passed through the outside air introduction path 22 flows uniformly into the arrangement part 4 from the entire periphery of the lower end part 28 of the inner sound insulation wall 18.

Next, the inflow of outside air to the sound insulation device 2 will be described. The upper part 14 of the outside air introduction path 22 opens at a position vertically below the discharge port 6 through which hot air is discharged. For this reason, the outside air introduction path 22 is configured such that hot air that is discharged from the discharge port 6 and flows upward does not easily flow in (reversely returns to the sound insulation device 2), and outside air easily flows in instead.
The outside air flowing into the outside air introduction path 22 passes through the outside air introduction path 22. The outside air introduction path 22 is isolated from the arrangement portion 4 by the porous member 24 and the inner sound insulating wall 18. For this reason, the heat of the generator 8 arrange | positioned at the arrangement | positioning part 4 is made hard to be transmitted to the external air which flowed into the external air introduction path 22. FIG. Therefore, outside air in a state where the temperature of the inflowing state is relatively maintained (suppressing increase in viscosity due to temperature rise as much as possible) passes through the outside air introduction path 22 and smoothly flows into the placement portion 4 through the communication hole 32. .

(II) of FIG. 3 is a partial longitudinal cross-sectional view of the sound insulation device for explaining the sound insulation and sound absorption actions. In the figure, the direction of noise transmission is indicated by a thick arrow.
The noise transmitted from the arrangement part 4 in the vertical direction upward is attenuated and reduced by the diaphragm effect (also called labyrinth effect) of the porous member 24 attached to the inner sound insulation wall 18. Further, the noise transmitted in the horizontal direction is reduced by the sound absorbing effect of the porous member 24 of the inner sound insulating wall 18 and the sound insulating effect of the double wall described above.
The noise transmitted from the generator 8 toward the communication hole 32 passes through the outside air introduction path 22 and is transmitted to the outside, and the separation width between the upper part 14 and the lower part 26 of the outside air introduction path 22 is increased. The noise that leaks to the outside can be reduced. And since the upper part 14 of the external air introduction path 22 is opened upward, noise is transmitted to the outside with its directivity directed upward. For this reason, it is possible to reduce the direct transmission of noise in the horizontal direction of the sound insulation device 2.
According to the above-described configuration, the configuration in which the outside air of the sound insulation device 2 is efficiently introduced to form a smooth air flow in the arrangement portion 4 is also a configuration for soundproofing. Since the smooth air flow and the soundproofing are achieved by the same configuration, the sound insulating device 2 becomes compact.

FIG. 4 is a longitudinal sectional view of the sound insulation device according to the first embodiment of another example.
In the sound insulation device 2a, the outer sound insulation wall 20 has a bottom wall 34 that supports the generator 8 from below. The upper surface 31 of the bottom wall 34 corresponds to the mounting surface. Since the other components are the same as the components of the above-described sound insulating device 2, detailed description thereof is omitted by attaching the same reference numerals to the same members. The bottom wall 34 receives and suppresses the vibration of the generator 8 transmitted downward. For this reason, the sound insulation performance of the sound insulation device 2a is further enhanced.

[Material]
The material of the sound insulation wall 19 (the inner sound insulation wall 18 and the outer sound insulation wall 20) may be a material having a performance of sound insulation, and is preferably a metal having a high surface density. Examples of the metal having a high surface density include iron, aluminum, stainless steel, and cast steel. Metals having a high surface density have a high sound transmission loss, so that the amount of sound transmitted through the sound insulation wall 19 can be reduced. In addition, it has enough mechanical properties to withstand vibrations and shocks generated from construction machinery. The sound insulation wall 19 made of aluminum is preferable because it is hard to be corroded and is not easily deformed against impact.
Moreover, when using the metal sound insulation wall 19 with high surface density, in order to suppress the weight increase of the sound insulation apparatus 2 itself, it is preferable that the thickness shall be about 0.5 mm-10 mm. If it is the thickness of this range, it will become the sound insulation apparatus 2 which has the size and weight which can obtain the practical sound insulation effect and can be conveyed.

  Moreover, a practical sound insulation effect can be obtained by using a composite material combined with a material having a high vibration damping capability (a vibration damping material) as the material of the sound insulation wall 19. As a composite material, there is a material in which an adhesive is applied to a thin metal foil and this is attached to a metal plate. For example, an aluminum foil (thickness: 6 to 200 μm) is adhesively coated on a metal plate such as iron to form the sound insulation wall 19. As the adhesive, a commercially available general adhesive (not containing an aluminum foil to be described later) can be used, and any adhesive that does not erode a metal plate or aluminum foil is preferable. Examples of adhesive components include epoxy resins, phenol resins, urethane resins, acrylic resins, polyethylene resins, polyester resins and vinyl acetate resins, silicone rubber, chloroprene rubber, acrylic rubber A rubber such as a synthetic rubber or a natural rubber may be used.

  Furthermore, you may mix 1-20% of aluminum foil particle | grains (particle size of 100 micrometers or less) with the said adhesive agent. When noise passes through the sound insulation wall 19 in which different materials are combined, the sound components constituting the noise are reflected by different materials and interfere with each other so as to cancel each other. If the aluminum foil to be mixed is less than 1%, a practical vibration damping effect cannot be obtained. Further, even if 20% or more is added, it is not preferable from the viewpoint of cost because it is impossible to obtain a vibration control effect corresponding to that. On the other hand, if the particle size of the aluminum foil is larger than 100 μm, the aluminum foil does not disperse well in the adhesive component and a desired interference action cannot be obtained. According to the above-described configuration, the sound insulation device can obtain a practical sound insulation effect while reducing the weight by reducing the thickness of the sound insulation wall 19.

As the material of the porous member 24, for example, metal fibers such as aluminum, rock wool (rock wool) using rock as a raw material, slag wool (mineral cotton) using blast furnace slag as a raw material, and inorganic materials such as glass wool using glass fiber as a raw material Organic fibers (hereinafter referred to as fibers) such as fibers, plant fibers such as cotton and hemp, and animal fibers such as feathers and animal hair are used. By forming these fibers into a cotton-like, board-like, or non-woven fabric-like member having many continuous gaps and bubbles between the fibers, the porous member 24 having sound absorbing performance is obtained. Further, a foamed resin material (urethane foam) obtained by foaming a polymer substance such as polyurethane may be used. A porous member 24 having sound absorption performance is obtained by connecting a plurality of bubbles formed inside the urethane foam to form continuous cells.
The porous member 24 and the inner sound insulating wall 18 may be bonded by baking, or may be bonded using an adhesive. The adhesive component used for bonding may be an adhesive having the above-described components as long as it does not erode the porous member 24 and the inner sound insulating wall 18 and has a required adhesive strength. Further, as described above, a specially formulated adhesive mixed with aluminum foil particles may be used.

[Second Embodiment]
FIG. 5 is a longitudinal sectional view of the sound insulating device according to the second embodiment.
In the sound insulation device 2 b according to the second embodiment, the upper wall 3 is formed on the inner sound insulation wall 18, and the upper wall 3 is configured to cover the upper side of the arrangement portion 4. Since the other components are the same as the components of the above-described sound insulation device 2 (2a), the detailed description thereof will be omitted by attaching the same reference numerals to the same members. A discharge port 6 a is formed in the upper wall 3 of the inner sound insulating wall 18. The diameter of the discharge port 6 a is narrowed to be smaller than the diameter of the inner sound insulation wall 18. This diaphragm effect (labyrinth effect) attenuates and reduces the vibration energy of noise transmitted in the same direction.
A fan 7 for forcibly discharging the air in the arrangement portion 4 is disposed at the discharge port 6a. For this reason, hot air is discharged | emitted from the discharge port 6a with a small diameter size to the perpendicular direction upper direction, and the smooth air flow in the arrangement | positioning part 4 can be maintained. Further, the discharge port 6 a is in a state of opening at a position spaced apart in the horizontal direction from the upper portion 14 of the outside air introduction path 22. Therefore, the upper portion 14 of the outside air introduction path 22 opens at a position separated from the discharge port 6a so that hot air discharged from the discharge port 6a does not flow.
Note that the porous member 24 may also be disposed on the upper wall 3 described above.

[ Reference example ]
FIG. 6 is a longitudinal sectional view of a sound insulation device according to a reference example .
In the sound insulating device 2 c according to the third embodiment, the inner sound insulating wall 18 is configured to block a part of the noise transmission path of the generator 8. That is, the inner sound insulation wall 18 is attached only to a part of the side facing the generator 8. The outer sound insulation wall 20 is also provided with a porous member 23 on an inner diameter surface 21 facing the generator 8. The upper end portion 16 of the outer sound insulation wall 20 facing the generator 8 and the upper end portion 10 of the inner sound insulation wall 18 form the discharge port 6 of the sound insulation device 2c. Since the other components are the same as the components of the above-described sound insulation device 2 (2a), the detailed description thereof will be omitted by attaching the same reference numerals to the same members.
In the sound insulating device 2c, since the inner sound insulating wall 18 for insulating the generator 8 is only partially formed, the weight of the sound insulating device 2c is reduced. For example, when other noise reduction effects such as distance attenuation and sound absorption effects on trees and the ground surface can be expected according to the situation of the construction site, the inner sound insulation wall 18 may only need to insulate part of the generator 8. In this case, it is preferable to use the sound insulation device 2c.

[Test example]
Hereinafter, the present embodiment will be described based on test examples. The present invention is not limited to this test example.
As Example 1 of this test example, the sound insulating device 2 according to the first embodiment was used (see FIGS. 1 to 3). A cylindrical wall body made of aluminum (outer diameter: 1500 mm, height: 700 mm, thickness: 10 mm) was used as the inner sound insulating wall 18. Further, as the outer sound-insulating wall 20, a cylindrical wall body made of aluminum (outer diameter dimension: 1350 mm, height dimension: 700 mm, thickness: 10 mm) was used. The upper part 14 of the outside air introduction path 22 was disposed 100 mm below the discharge port 6. The width dimension of the outside air introduction path 22 (clearance Cg between the inner sound insulation wall 18 and the outer sound insulation wall 20) was set to 100 mm. Then, the lower end portion 28 of the inner sound insulation wall 18 was lifted 100 mm from the mounting surface 30 and fixed to the outer sound insulation wall 20. That is, the width dimension of the communication hole 32 (clearance Cr between the inner sound insulation wall 18 and the mounting surface 30) was set to 100 mm.
A porous member 24 made of urethane foam was bonded and fixed to the inner sound insulation wall 18 and further supported by L-shaped steel in a reinforcing manner. An adhesive containing chloroprene rubber was used as the adhesive. The longitudinal cross section of the porous member 24 has an arc shape. The thickness of the central portion 24b of the porous member 24 was 100 mm, and the thickness of both ends 24a and 24c of the porous member 24 was 0. The clearance between the central portion 24b of the porous member 24 and the generator 8 was set to 100 mm.

  As Comparative Example 1, a conventional sound insulation device 52 shown in FIG. 6 was used. As the sound insulation wall 70, a rectangular wall body made of aluminum (outer diameter dimension: 1000 mm × 900 mm, height dimension: 600 mm, thickness: 10 mm) was used. A sound absorbing wall 73 made of urethane foam and having a plate-like sound absorbing member 73 (thickness: 50 mm) was adhered and fixed to the sound insulating wall 70.

(Temperature measurement test)
FIG. 9 is a schematic plan view of a sound insulation device for explaining a method for carrying out a temperature measurement test.
A generator 8 is arranged in the arrangement part 4 of the above-described sound insulation device 2 (Example 1), and thermometers are installed at four locations A, B, C, D around the generator 8 (see (I) in FIG. 9). reference). After operating the generator 8 for 2 hours under an outside air temperature of 5 ° C., the temperatures at the four locations A, B, C, and D were measured.
And the generator 8 is arrange | positioned in the arrangement | positioning part 4 of the above-mentioned sound insulation apparatus 52 (comparative example 1), and the thermometer was installed in four places E, F, G, H around the generator 8 ((II of FIG. 9). )). And the temperature of the said four places E, F, G, and H was measured on the conditions similar to Example 1. FIG.

(Noise measurement test)
FIG. 10 is a schematic plan view of a sound insulation device for explaining a method for carrying out a noise measurement test.
A generator 8 is arranged in the arrangement part 4 of the above-described sound insulation device 2 (Example 1). And the sound level meter 80 was arrange | positioned 7.5 m away from the sound insulation apparatus 2 in the horizontal direction. The sound collecting microphone 82 of the sound level meter 80 was installed at a distance of 1.2 m from the mounting surface 30 in the vertical direction. After the generator 8 is operated for 2 hours, the “equivalent noise level (L _{Aeq, T} , hereinafter referred to as“ noise level L _{Aeq, T} ”)” and “5 percent time rate noise level (L _{A5 , T} , hereinafter referred to as “noise level L _{A5, T} ”)) ”(JIS Z 8731).
And the generator 8 is arrange | positioned in the arrangement | positioning part 4 of the above-mentioned sound insulation apparatus 52 (comparative example 1), and the noise level L _{Aeq, T} of the sound insulation apparatus 52 and the noise level L _{A5, T} was measured.
Moreover, as the comparative example 2, only the generator 8 was arrange | positioned and the noise was measured on the conditions similar to Example 1. FIG. Further, the noise (background noise) generated from the surrounding environment without driving the generator 8 was measured.
Noise measurement was performed by the method described in JIS Z8731. As the sound level meter 80, a sound level meter and a level recorder having the conditions set in [Table 1] below were used in combination. A sound level meter conforming to JISC 1502 was used. The level recorder used conformed to JIS C 1512.

Table 2 is a table showing the results of the temperature measurement test.
In the sound insulation device 2 of Example 1, the temperature rise of the arrangement part 4 was relatively suppressed even after 2 hours had passed since the generator 8 was operated. Thereby, in the sound insulation apparatus 2 of Example 1, it turned out that the smooth air flow from the perpendicular direction bottom to the top arises in the arrangement | positioning part 4, and ventilation with the hot air in the arrangement | positioning part 4 and external air was performed smoothly. It was. On the other hand, in the sound insulation device 52 of Comparative Example 1, the temperature of the arrangement portion 4 rose to an average of 65 ° C. even when the outside air temperature was 5 ° C.

Table 3 is a table showing the results of the noise measurement test.
In the sound insulation device 2 of the first embodiment, the noise level L _{Aeq, T} is reduced by 6.9 dB and the noise level L _{A5, T} is reduced by 6.2 dB compared to the comparative example 2 in which only the generator 8 is arranged. In particular, the noise level L _{A5, T} in the sound insulation device 2 of Example 1 could be reduced to substantially the same level as background noise. On the other hand, in the sound insulation device 52 of the comparative example 1, both the noise level L _{Aeq, T} and the noise level L _{A5, T} were reduced to 3.7 dB.

  From the above results, the sound insulation device 2 according to the present embodiment takes in the outside air efficiently while suppressing the noise of the generator 8 in the arrangement part 4 from being transmitted to the outside as much as possible, and smoothly flows the air in the arrangement part 4. It was found that can be formed. Moreover, even if the generator 8 is operated for a long time (two hours or more), it is estimated that the temperature rise in the placement unit 4 can be suppressed. For this reason, it is expected that the possibility of troubles such as overheating occurring in the generator 8 becomes very low. In the conventional sound insulation device 52 of Comparative Example 1, it is easily estimated that the generator 8 may become relatively hot due to a temperature rise in the placement unit 4 if the generator 8 is kept in operation. The

The sound insulation device of the present embodiment is not limited to the appearance, configuration, processing, display example, and the like described in the present embodiment, and various modifications, additions, and deletions can be made without changing the gist of the present invention. .
In the present embodiment, the example of the cylindrical sound insulating wall 19 (the inner sound insulating wall 18 and the outer sound insulating wall 20) has been described. However, the outer shape of the sound insulating wall 19 can be appropriately changed according to the outer shape of the noise source. is there. For example, a simple construction machine (for example, a plate compactor) that can be carried by a worker alone is preferred because it is light in weight and has good workability. When the generator or engine of such a construction machine has an outer shape such as a rectangular parallelepiped, the dead space in the arrangement portion may be reduced to form a compact rectangular tube shape.

In the present embodiment, the inner sound insulating wall 18 is welded and fixed to the outer sound insulating wall 20 with the plate-shaped fixtures 17a to 17d. There is no limitation on the material and shape of the fixture as long as it has rigidity and strength capable of stably mounting and supporting the inner sound insulating wall on the outer sound insulating wall. For example, metal fittings such as stainless steel and iron are preferable because they can withstand vibrations generated from noise sources of construction machines. Alternatively, the inner sound insulation wall may be screwed to the outer sound insulation wall using a fixture made of bolts or rivets.
In the present embodiment, the example of the sound insulating device 2 in which the inner sound insulating wall 18 is integrally attached to the outer sound insulating wall 20 has been described. Unlike this, the inner sound insulation wall and the outer sound insulation wall may be separated. For example, an adjuster (such as a caster) such as a support leg is attached to the lower edge of the inner sound insulation wall. A clearance Cr between the inner sound insulating wall and the mounting surface is secured by the adjuster. Since the inner sound insulating wall and the outer sound insulating wall are separated, the inner sound insulating wall and the outer sound insulating wall can be moved separately, and the clearance Cg between the inner sound insulating wall 18 and the outer sound insulating wall 20 (the width dimension of the outside air introduction path 22). ) Can be finely adjusted.

  In the present embodiment, an example in which the lower portion of the inner sound insulating wall 18 and the arrangement portion 4 are communicated with each other through the communication hole 32 is shown. Alternatively, a plurality of communication holes may be provided in the lower part of the inner sound insulation wall, and the communication path may communicate with the outside air introduction path. There is no need to dispose the inner sound insulating wall so that the clearance Cr is provided between the inner sound insulating wall and the mounting surface, and the work of disposing the inner sound insulating wall is facilitated.

  In the present embodiment, the example of the porous member 24 whose longitudinal section has an arc shape has been described. Unlike this, the longitudinal cross section of the porous member may be a polygonal shape such as a triangle or pentagon, or an angular shape such as a step shape. Further, the porous member may be a flat member having a flat cross section.

In the present embodiment, the example of the porous member 24 has been described as the sound absorbing member. Unlike this, a member having a structure for absorbing sound may be used as the sound absorbing member.
The structure that absorbs sound is, for example, a structure in which a through-hole is provided in a composite material such as a metal plate or a plywood (a perforated plate sound absorbing structure). When sound enters the through hole of the plate material, the air near the tube wall of the hole resonates. The vibration energy of the resonated air is absorbed by friction with the tube wall of the hole. A sound absorbing member may be disposed behind the inner sound insulating wall 18 of the perforated plate sound absorbing structure. The vibration of the air can be further absorbed by the porous member disposed behind the inner sound insulating wall 18. That is, a porous member as a sound absorbing member may be provided on the outer diameter surface side of the inner sound insulating wall 18 of the perforated plate sound absorbing structure. Furthermore, the inner sound insulation wall 18 of the perforated plate sound absorbing structure may be formed into a hollow shape, and a porous member may be disposed inside the hollow. That is, a porous member as a sound absorbing member may be provided inside the inner sound insulating wall 18.
Further, a flexible material (for example, flexible urethane foam) having a high elasticity and a low air permeability may be used as the sound absorbing member. The vibrational energy of the noise is attenuated and reduced by the resonance effect derived from the flexibility of the flexible urethane foam. Since the flexible material resonates with a sound having a specific frequency and exhibits a large sound absorption effect, the flexible material is effective for a noise generation source that generates noise having a specific frequency.

  In the present embodiment, the example in which the fan 7 is used as the discharging means has been described. Any device and instrument may be used as the discharge means as long as the hot air in the arrangement portion can be discharged to the outside. For example, the hot air may be sucked and discharged by an air duct. By appropriately changing the installation location of the air duct outlet for discharging hot air, the hot air can be discharged to a convenient location. A plurality of discharging means can be provided.

  In the present embodiment, the example of the generator 8 has been described as a noise generation source. The noise generation source in the present embodiment refers to a sound source that generates sound (noise) by causing a change in the pressure of the surrounding air. Examples of noise generation sources include an engine, a compressor, a pump, a motor, and a boiler. Noise sources may be used as part of a device such as a plate compactor or rock drill. The sound insulation device in the present embodiment can be applied to any noise generation source.

It is a perspective view of the sound insulation apparatus concerning a first embodiment. It is a longitudinal cross-sectional view of the sound insulation apparatus concerning 1st embodiment. BRIEF DESCRIPTION OF THE DRAWINGS It is a partial longitudinal cross-sectional view of the sound insulation apparatus concerning 1st embodiment, (I) is a figure of the sound insulation apparatus for demonstrating an air flow, (II) demonstrates the sound insulation and sound absorption effect | action. FIG. It is a longitudinal cross-sectional view of the sound insulation apparatus concerning 1st Embodiment of another example. It is a longitudinal cross-sectional view of the sound insulation apparatus concerning 2nd embodiment. It is a longitudinal cross-sectional view of the sound insulation apparatus concerning 3rd embodiment. It is a longitudinal cross-sectional view of the conventional sound insulation apparatus. It is a longitudinal cross-sectional view of the sound insulation apparatus different from the past. It is a schematic plan view for demonstrating a temperature measuring method, (I) is a schematic plan view of the sound insulation apparatus concerning 1st embodiment, (II) is a schematic plan view of the conventional sound insulation apparatus. is there. It is a schematic front view for demonstrating the noise measuring method.

Explanation of symbols

2 Sound insulation device (first embodiment)
2a Sound insulation device (modified example of the first embodiment)
2b Sound insulation device (second embodiment)
2c Sound insulation device (third embodiment)
3 Upper wall 4 Arrangement part 6 Discharge port 6a (Other example) Discharge port 7 Fan 8 Generator 9 Inner surface of inner sound insulation wall 10 Upper end portion of inner sound insulation wall 12 Outer surface of inner sound insulation wall 14 Upper portion of external introduction path 16 Outside Upper end portions 17a, 17b, 17c, and 17d of the sound insulation wall Attaching tool 18 Inner sound insulation wall 19 Sound insulation wall 20 Outer sound insulation wall 21 Other inner diameter surface 22 of the outer sound insulation wall 23 Outside air introduction path 23 The central part 24 of the porous member 24 The porous member 26 The lower part 28 of the outside air introduction path The lower end part 30 of the inner sound insulation wall 30 The mounting surface 32 The communication hole 34 The bottom part wall

Claims (1)

An arrangement part in which a noise generating source for generating hot air is arranged, an inner sound insulation wall to which a sound absorbing member that absorbs noise of the noise generation source is attached and arranged outside the arrangement part, the inner sound insulation wall and the arrangement part And an outer sound insulation wall arranged so as to surround, and a discharge port that is formed vertically above the arrangement part so as to discharge hot air from the noise generation source and is open to the outside air ,
An outside air introduction path is formed between the inner sound insulation wall and the outer sound insulation wall to guide the outside air to the arrangement part. It is configured to communicate with the arrangement so that a flow is generated,
The upper part of the outside air introduction path opens outside the discharge port and at a vertically lower position than the discharge port so that hot air discharged from the discharge port does not flow in,
The inner sound insulation wall is disposed so as to surround the arrangement portion, and the sound absorbing member is attached to the entire surface of the inner sound insulation wall facing the noise generation source,
The sound insulating device , wherein a longitudinal section of the sound absorbing member has a convex shape protruding toward the noise generating source .

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