Exterior wall structure

Abstract

To provide an exterior wall structure that can suppress indoor noise levels.SOLUTION: A building exterior wall structure 100 according to the present invention comprises a first exterior wall 110 arranged on the indoor side, a second exterior wall 210 arranged on the outdoor side of the first exterior wall 110, and a protrusion 310 arranged to protrude from the first exterior wall 110 to the outdoor side. When the angle formed by the plane connecting a second exterior wall upper end 221 of the second exterior wall 210 and a protrusion tip 322 of the protrusion 310 and the vertical plane is θ2, and the angle formed by the direction in which sound waves enter the building and the vertical plane is θ0, there is a relationship of θ2≥θ0.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to an exterior wall structure that constitutes the exterior wall of a building. [Background technology]

[0002] One known exterior wall structure used to improve the thermal insulation performance of a building is one with a double-skin structure 1 as shown in Figure 14. This type of double-skin structure 1 has an inner skin 2 on the indoor side of the building and an outer skin 6 that is spaced a predetermined distance from the inner skin 2 and covers almost the entire surface of at least one side of the building, forming the outermost wall of the building. The inner skin 2 and outer skin 6 are generally assumed to be primarily made of glass.

[0003] In the double skin structure 1, a space (air layer 10) is provided between the outer skin 6 and the inner skin 2. The air layer 10 can serve as a thermal buffer zone between the outdoors and the indoors, and can contribute to reducing the heating and cooling load within the building. For example, in summer, to prevent the temperature within this air layer 10 from rising, an opening between the outer skin 6 and the inner skin 2, or an opening provided in part of the outer skin 6, allows outside air to be introduced into the air layer 10 and ensures air circulation.

[0004] To date, the inventors have proposed noise control methods such as those shown in Patent Document 1 (JP 2018-53463 A) and Patent Document 2 (JP 2018-131895 A) in relation to the deterioration of the sound insulation performance of the above-mentioned double skin structure 1. [Patent Document 1] Japanese Patent Application Publication No. 2018-53463 [Patent Document 2] Japanese Patent Application Publication No. 2018-131895 Summary of the Invention [Problem to be solved by the invention]

[0005] In this specification, the structure of the exterior wall of a building or other structure, including the double skin structure 1 described above, will be referred to as the exterior wall structure 100 as a general concept. In addition to the double skin structure 1, the exterior wall structure 100 can also include double soundproof structures such as double window sashes and double glass curtain walls.

[0006] 15 is a diagram showing a schematic cross section of an exterior wall structure 100 such as a double skin structure 1. In the exterior wall structure 100, a first exterior wall 110 corresponds to the inner skin 2 of the double skin structure 1, and a second exterior wall 210 corresponds to the outer skin 6 of the double skin structure 1. Note that the actual exterior wall structure 100 is configured to extend in a direction perpendicular to the plane of the paper on which the schematic cross section is drawn.

[0007] This exterior wall structure 100 also functions as a double soundproofing structure consisting of the second exterior wall 210 and the first exterior wall 110. However, if roads or railroad tracks are present around the building, these may generate high levels of noise, significantly affecting buildings facing these areas. This is illustrated in Figure 15, where noise is incident on the second exterior wall 210 of the exterior wall structure 100 as indicated by the arrows. The noise incident on the second exterior wall 210 propagates through the air layer 10 and penetrates the interior side of the first exterior wall 110, causing a problem of increasing the noise level indoors.

[0008] If an exterior wall structure 100 was adopted that reduced the noise level inside the building without changing the lines on the outermost side of the building, the width of the air layer (left and right in Figure 15) would have to be made larger, which would have reduced the effective area inside the building, creating a problem. [Means for solving the problem]

[0009] This invention solves the above-mentioned problems, and the exterior wall structure of the present invention is an exterior wall structure of a building, and comprises a first exterior wall arranged on the indoor side, a second exterior wall arranged on the outdoor side of the first exterior wall, and a protrusion arranged to protrude from the first exterior wall to the outdoor side, wherein the angle formed by the plane connecting the upper end of the second exterior wall and the tip of the protrusion and the vertical plane is θ2, and the angle formed by the direction in which sound waves are incident on the building and the vertical plane is θ0, so that there is a relationship θ2≧θ0.

[0010] In the exterior wall structure according to the present invention, the lower surface of the protrusion is parallel to the horizontal plane.

[0011] In addition, in the exterior wall structure according to the present invention, the lower surface of the overhang is subjected to sound-absorbing treatment.

[0012] Furthermore, in the exterior wall structure according to the present invention, if the angle between the vertical plane and the direction in which sound waves enter the building is θ0, then θ2=θ0.

[0013] Furthermore, in the exterior wall structure according to the present invention, the angle θ2 in the second exterior wall becomes smaller the higher the floor of the building.

[0014] Furthermore, in the exterior wall structure of the present invention, if the angle between the underside of the protrusion and the horizontal plane is θ3 and the angle between the vertical plane and the direction in which sound waves enter the building is θ0, then θ3 = θ0.

[0015] In the exterior wall structure according to the present invention, when the angle formed between the lower surface of the protrusion and the horizontal plane is θ3, θ2=θ3.

[0016] In the outer wall structure according to the present invention, the upper end of the second outer wall and the base end of the protrusion are disposed at approximately the same location.

[0017] Furthermore, in the exterior wall structure according to the present invention, the angle θ2 in the second exterior wall becomes smaller the higher the floor of the building. [Effects of the Invention]

[0018] The exterior wall structure of the present invention has a structure consisting of a second exterior wall having a second surface whose angle θ2 with the vertical plane is greater than 0°, and a protrusion arranged to protrude toward the outdoors.With this exterior wall structure of the present invention, it is possible to reduce noise incident on the first exterior wall, and suppress the noise level indoors.

[0019] Furthermore, the exterior wall structure of the present invention makes it possible to create a layout that maintains the outermost exterior line of the building, reduces the noise level inside the building, and does not compress the effective area inside the building. [Brief explanation of the drawings]

[0020] [Figure 1] 2 is a diagram illustrating the relationship between a first outer wall 110 and a second outer wall 210 in an outer wall structure 100. FIG. [Figure 2] 1 is a diagram illustrating the relationship between a first outer wall 110 and a protrusion 310 in an outer wall structure 100. FIG. [Figure 3] 10 is a diagram illustrating the relationship between the second outer wall 210 and the overhang 310. FIG. [Figure 4] 1 is a schematic diagram showing an exterior wall structure 100 according to a first embodiment of the present invention. [Figure 5] 1 is a schematic diagram showing an exterior wall structure 100 according to a first embodiment of the present invention and the direction in which sound waves arrive. [Figure 6] FIG. 2 is a schematic diagram showing a modified example of the exterior wall structure 100 according to the first embodiment of the present invention. [Figure 7] FIG. 2 is a schematic diagram showing a modified example of the exterior wall structure 100 according to the first embodiment of the present invention. [Figure 8] FIG. 2 is a schematic diagram showing a modified example of the exterior wall structure 100 according to the first embodiment of the present invention. [Figure 9] FIG. 2 is a schematic diagram showing an exterior wall structure 100 according to a second embodiment of the present invention. [Figure 10] 10 is a schematic diagram showing an exterior wall structure 100 according to a second embodiment of the present invention and the direction in which sound waves arrive. FIG. [Figure 11] FIG. 10 is a schematic diagram showing a modified example of the exterior wall structure 100 according to the second embodiment of the present invention. [Figure 12] FIG. 2 is a schematic diagram illustrating differences between embodiments. [Figure 13] 1 is a schematic diagram showing one embodiment of an exterior wall structure 100 according to the present invention. [Figure 14] FIG. 1 is a diagram illustrating a conventional general double skin structure 1. [Figure 15] 1 is a diagram showing a cross section of an exterior wall structure 100 such as a double skin structure 1. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0021] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In describing an exterior wall structure 100 according to the present invention, first, the terms used in this specification will be explained with reference to FIGS.

[0022] FIG. 1 is a diagram explaining the relationship between the first exterior wall 110 and the second exterior wall 210 in the exterior wall structure 100, and is a schematic diagram of the cross section of each component. Each component, vertical plane, and horizontal plane extend in the direction perpendicular to the paper on which the schematic diagram is drawn. In addition, the diagram mainly illustrates the components of the first exterior wall 110 and the second exterior wall 210 relating to the Nth to (N+1)th floors. Similar drawings will use the same drawing method hereinafter.

[0023] An exterior wall structure 100 that constitutes the exterior of a building or other structure is composed of a first exterior wall 110 that is arranged on the indoor side, and a second exterior wall 210 that is arranged on the outdoor side of the first exterior wall 110 and constitutes the outermost exterior of the building.

[0024] The first exterior wall 110 has two opposing main surfaces. That is, the first exterior wall 110 has a first front surface 111 and a first back surface 112 that is opposite the first front surface 111. The first back surface 112 is configured to be in contact with the interior space of the building. In the drawing, the first exterior wall 110 is shown as if it is continuous between the upper and lower floors, but there may be inclusions such as joints or spaces such as gaps at the gaps between each floor.

[0025] In this embodiment, an example will be described in which the first surface 111 and the first back surface 112 are parallel to a vertical plane and the first surface 111 and the first back surface 112 are also parallel to each other, but these are not essential requirements.

[0026] The second exterior wall 210, which is disposed on the outdoor side of the first exterior wall 110, also has two opposing main surfaces. That is, the second exterior wall 210 has a second front surface 211 and a second back surface 212 that is opposite to the second front surface 211. The second surface 211 of the second exterior wall 210 is the surface that is exposed to noise from roads and railway tracks that exist around the building.

[0027] In this embodiment, the second surface 211 and the second back surface 212 of the second outer wall 210 are parallel to each other. However, the second surface 211 and the second back surface 212 of the second outer wall 210 do not necessarily have to be parallel to each other. However, in the present invention, the second surface 211 side of the second outer wall 210 is the surface exposed to noise, and therefore the second surface 211 is used as the reference surface. The upper end of the second outer wall 210 is referred to as the second outer wall upper end 221, and the lower end of the second outer wall 210 is referred to as the second outer wall lower end 222. The second outer wall upper end 221 and the second outer wall lower end 222 of the second outer wall 210 are supported by a configuration not shown in FIG. 1 .

[0028] Next, we will explain the overhang 310 used in the exterior wall structure 100 according to the present invention. Figure 2 is a diagram explaining the relationship between the first exterior wall 110 and the overhang 310 in the exterior wall structure 100. The overhang 310 is configured to protrude from the first exterior wall 110 to the outdoors. In Figure 2, the overhang 310 is configured to be provided at the boundary between each floor, but it is not essential to provide the overhang 310 on each floor.

[0029] The overhang 310 has two opposing main surfaces. That is, the overhang 310 has a lower overhang surface 311 and an upper overhang surface 312, which is the opposite surface of the lower overhang surface 311. The overhang 310 is provided so as to protrude from the first exterior wall 110 toward the exterior. The tip of the overhang 310 closest to the exterior is defined as the overhang tip 322. The angle between the lower overhang surface 311 and the horizontal plane is defined as θ3. In this embodiment, θ3 ≥ 0°. In the overhang 310, the side facing the lower overhang surface 311 is the surface exposed to noise, and therefore the lower overhang surface 311 is used as the reference surface. The lower overhang surface 311 and the upper overhang surface 312 do not necessarily need to be parallel. In this specification, unless otherwise specified, the "angle between surface A and surface B" refers to the smaller angle between the respective surfaces.

[0030] Next, the relationship between the second exterior wall 210 and the overhang 310 in the exterior wall structure 100 according to the present invention will be described. FIG. 3 is a diagram illustrating the relationship between the second exterior wall 210 and the overhang 310. As shown in FIG. 3, the second exterior wall 210 is configured to bridge the gap between the overhang 310 protruding from the (N+1)th floor and the overhang 310 protruding from the Nth floor. The upper end 221 of the second exterior wall of the exterior wall structure 100 is connected to the overhang 310 protruding from the (N+1)th floor, and the lower end 222 of the second exterior wall of the exterior wall structure 100 is connected to the overhang 310 protruding from the Nth floor. Here, the angle formed by the plane connecting the upper end 221 of the second exterior wall connected to the overhang 310 on the (N+1)th floor and the overhang tip 322 of the overhang 310 protruding from the Nth floor and the vertical plane is defined as θ2.

[0031] Next, an exterior wall structure 100 according to the present invention will be described. Fig. 4 is a schematic diagram showing the exterior wall structure 100 according to a first embodiment of the present invention. Fig. 5 is a schematic diagram showing the exterior wall structure 100 according to the first embodiment of the present invention and the direction in which sound waves arrive.

[0032] In the exterior wall structure 100 according to the first embodiment, overhangs 310 are provided so as to protrude horizontally from each floor level. If the angle formed between the underside 311 of the overhang and the horizontal plane is θ3, then the underside 311 of the overhang and the horizontal plane are parallel, and therefore θ3 = 0° in the exterior wall structure 100 according to the first embodiment. Furthermore, the material of the overhang 310 can be, for example, a steel panel or a PC (polycarbonate) plate, but any material can be used as long as it has a certain level of sound insulation performance.

[0033] Here, the portion of the protruding underside 311 that is exposed to the outside can be sound-absorbing treated. The sound-absorbing material used for sound-absorbing treatment can be glass wool, urethane foam, polyester sound-absorbing material, etc., but the material is not limited to these sound-absorbing materials as long as it has sufficient sound-absorbing performance. Considering that the sound-absorbing material is applied to the protruding underside 311, which is the exterior part, it is desirable that the sound-absorbing material have high weather resistance.

[0034] In the exterior wall structure 100 according to the first embodiment, the protruding tip 322 and the second exterior wall lower end 222 of the second exterior wall 210 are arranged so as to be continuous with each other. Therefore, in this embodiment, the angle formed between the second surface 211 (or the second back surface 212) of the second exterior wall 210 and the vertical plane is θ2. When connecting the protruding tip 322 and the second exterior wall lower end 222 of the second exterior wall 210, a member such as a joint can be used as appropriate.

[0035] In the exterior wall structure 100 according to the present invention, the angle between the direction in which sound waves enter the building and the vertical plane is set to θ0, so that the relationship θ2≧θ0 holds. In this embodiment, the second surface 211 of the second exterior wall 210 is parallel to the expected direction in which sound waves (noise) are coming. This can be expressed as the relationship between the angles in the figure, θ2=θ0.

[0036] When road or railroad noise is sufficiently far away, the sound waves coming from the source can be approximately considered as plane waves propagating in a straight line. Here, "the direction in which sound waves enter a building" refers to the direction in which noise from roads or railroad tracks arrives at a building when the building is surrounded by roads or railroad tracks. Since the position of roads and railroad tracks does not change relative to the building, the "direction in which sound waves enter a building" is a direction specific to each building's facade. If a more detailed discussion is required, the "direction in which sound waves enter a building" will change depending on the number of floors in the building.

[0037] In exterior wall structure 100 according to the present invention, sound waves that reach the exterior of the building from a noise source below are partially blocked from propagating to upper floors by overhang 310, and at the same time, if overhang undersurface 311 is sound-absorbing treated, the sound waves are partially absorbed by sound-absorbing treatment section 340. Sound waves propagate through the space between overhangs 310 on the upper and lower floors of floor N of interest, but because second surface 211 of second exterior wall 210 is parallel to the propagation direction of the sound waves, second exterior wall 210 is not directly exposed to the sound waves.

[0038] Sound waves diffracted by the tip 322 of the projection 310 enter the second exterior wall 210, but because the exterior wall structure 100 of the present invention has a double sound-insulating structure, it is possible to sufficiently reduce the sound propagating toward the interior of the room. The sound-insulating exterior of the exterior wall structure 100 of the present invention as described above prevents the exterior surface from being directly exposed to sound waves, thereby achieving quietness within the room. This effect can be achieved without reducing the effective area of ​​the room.

[0039] An embodiment may be considered in which the inclination angle (same as θ2 in this example) of the second surface 211 of the second exterior wall 210 is changed so as to be parallel to the incident angle (same definition as θ0) of the sound wave (noise) on a target floor of the building. Such an embodiment will be described later.

[0040] Next, another embodiment of the exterior wall structure 100 according to the present invention will be described. Fig. 6 is a schematic diagram showing a modified example of the exterior wall structure 100 according to the first embodiment of the present invention. In the previous embodiment, the relationship between the angle θ2 formed by the plane connecting the second exterior wall upper end 221 and the protruding tip 322 and the vertical plane and the angle θ0 formed by the direction of arrival of the sound wave (noise) and the vertical plane was set to be θ2 = θ0, but in the modified example shown in Fig. 6, the relationship is set to be θ2 > θ0.

[0041] In exterior wall structure 100 according to this modified example, sound waves that reach the exterior of the building from a noise source below are partially blocked from propagating to upper floors by overhang 310 on the Nth floor. Sound waves that are not blocked by overhang 310 and propagate upward do not strike second surface 211 of second exterior wall 210 because of the relationship θ2 > θ0.

[0042] Next, another embodiment of the exterior wall structure 100 according to the present invention will be described. Fig. 7 is a schematic diagram showing a modified example of the exterior wall structure 100 according to the first embodiment of the present invention. In the exterior wall structure 100 according to the first embodiment described in Figs. 4, 5, and 6, the protrusion tip 322 and the second exterior wall lower end 222 of the second exterior wall 210 from the upper floor are arranged so as to be continuous with each other.

[0043] On the other hand, in this modified example, the protrusion tip 322 and the second outer wall lower end 222 are not connected to each other. That is, the second outer wall lower end 222 is connected to the protrusion upper surface 312 between the protrusion base end 321 and the protrusion tip 322. However, even in this example, the relationship between the angle θ2 formed by the plane connecting the second outer wall upper end 221 and the protrusion tip 322 and the vertical plane and the angle θ0 formed by the direction of arrival of the sound waves (noise) and the vertical plane is set to be θ2 ≧ θ0. This modified example can be adopted when it is desired to make the second outer wall 210 more vertical for design reasons.

[0044] It should be noted that, in order to maximize the air gap 10 formed between the first outer wall 110 and the second outer wall 210, it is undeniable that it is desirable that the inclination (angle θ2) of the second surface 211 be parallel to the direction from which the noise is coming (angle θ0). This is because, by increasing the air gap 10, sound waves that pass through the room can be attenuated to a greater extent.

[0045] In this regard, the embodiment shown in Fig. 8 will be described. Fig. 8 is a schematic diagram showing a modified example of the exterior wall structure 100 according to the first embodiment of the present invention. In this modified example, the second exterior wall upper end 221 of the second exterior wall 210 is connected to the overhang base end 321 of the overhang 310 of the upper floor. When such a structure is adopted, the first exterior wall 110 and the second exterior wall 210 are closer to each other than in the example shown in Fig. 4, making it impossible to create a large air layer 10. On the other hand, there is an advantage in that the overall width of the exterior wall structure 100 (in the left-right direction on the paper) can be reduced, making it easier to ensure space on the indoor side.

[0046] As described above, the exterior wall structure 100 of the present invention has a relationship of θ2≧θ0, where θ2 is the angle between the plane connecting the second exterior wall upper end 221 of the second exterior wall 210 and the protrusion tip 322 of the protrusion 310 and the vertical plane, and θ0 is the angle between the direction in which sound waves enter the building and the vertical plane.With such exterior wall structure 100 of the present invention, it is possible to reduce the noise incident on the first exterior wall 110 and suppress the noise level indoors.

[0047] Furthermore, with the exterior wall structure 100 of the present invention, it is possible to create a layout that maintains the outermost exterior line of the building, reduces the noise level inside the building, and does not compress the effective area inside the building.

[0048] Furthermore, the exterior wall structure 100 according to the present invention makes it possible to implement soundproofing measures for the exterior of a building without restricting the effective area of ​​the room.

[0049] Furthermore, with the exterior wall structure 100 according to the present invention, the outermost surface is not directly exposed to sound waves, making it possible to achieve quietness within the room. This effect can be achieved without reducing the effective area of ​​the room.

[0050] Furthermore, the exterior wall structure 100 according to the present invention is less affected by diffracted waves at the protruding tip 322, and when the first exterior wall 110 is omitted from the soundproof structure, a larger effective area can be secured inside the room.

[0051] Furthermore, in the exterior wall structure 100 according to the present invention, the overhang 310 also functions as a canopy that blocks sunlight, thereby reducing the heat load on the building and saving energy.

[0052] Next, another embodiment of the exterior wall structure 100 according to the present invention will be described. In the previous embodiment, the angle between the plane connecting the second exterior wall upper end 221 of the second exterior wall 210 and the protrusion tip 322 of the protrusion 310 and the vertical plane is defined as θ2, and the angle between the direction in which sound waves enter the building and the vertical plane is defined as θ0. The relationship θ2 ≧ θ0 is satisfied, and a sound-insulating structure is provided with the protrusion 310. If necessary, the underside 311 of the protrusion is provided with a sound-absorbing treatment part 340 made of glass wool or the like. However, the sound-absorbing treatment part 340 has problems such as requiring maintenance due to dirt and low durability, and the frequency dependency of the noise reduction effect due to the frequency dependency of the sound absorption effect.

[0053] Fig. 9 is a schematic diagram showing an exterior wall structure 100 according to a second embodiment of the present invention. Fig. 10 is a schematic diagram showing the exterior wall structure 100 according to the second embodiment of the present invention and the direction of arrival of sound waves. Hereinafter, components having the same reference numbers as those in the previous embodiment are the same as those in the previous embodiment, and therefore their explanation may be omitted.

[0054] In the exterior wall structure 100 according to the second embodiment, by inclining the protrusion lower surface 311, it is possible to prevent sound waves reflected by the protrusion 310 from entering the second exterior wall 210. That is, when the angle formed between the protrusion lower surface 311 and the horizontal plane is θ3, this can be achieved by at least satisfying θ3 > 0°.

[0055] In yet another aspect, in exterior wall structure 100 according to a second embodiment, the above-mentioned problems can be solved by a sound-insulating exterior comprising a first exterior wall 110 having a vertical first surface 111, a protrusion 310 having a protrusion lower surface 311 perpendicular to the direction of arrival of incident noise, and a second exterior wall 210 having a second surface 211 inclined so as to be parallel to the direction of arrival of the noise. That is, in this embodiment, sound waves that reach the exterior of the building from a noise source below are reflected by protrusion lower surface 311 in the opposite direction to the direction of arrival.

[0056] In the exterior wall structure 100 according to the second embodiment, if the angle between the protrusion lower surface 311 and the horizontal plane is θ3, then the angle between the vertical plane and the direction in which sound waves enter the building, θ0, can be set so that the relationship θ3 = θ0 holds. Furthermore, when the second exterior wall lower end 222 and the protrusion tip 322 are connected, if the second surface 211 of the second exterior wall 210 is set so as to be parallel to the direction in which sound waves (noise) are arriving, then θ2 = θ0 (= θ3). This makes it possible to achieve a situation in which the second exterior wall 21 is not directly exposed to sound waves.

[0057] 9 and 10, the protruding lower surface 311 is perpendicular to the direction in which the noise is coming, but the inclination angle (same definition as θ3) may be larger. In other words, θ3 > θ0 may be set. In this case, the noise reflected by the protruding lower surface 311 is reflected in a direction further away from the building than the direction in which it came, and therefore does not strike the exterior of the building.

[0058] If, as in the exterior wall structure 100 according to the first embodiment, a sound-absorbing processing section 340 using sound-absorbing material is provided to process the reflected sound from the protruding underside 311, the noise reduction effect will be frequency-dependent due to the frequency dependency of the sound absorption effect, but in the exterior wall structure 100 according to the second embodiment, the protruding underside 311 is tilted to change the direction of noise reflection, so there is less frequency dependency as with the use of sound-absorbing material, and it is possible to expect a noise reduction effect across almost the entire frequency band. Also, compared to the exterior wall structure 100 according to the first embodiment, no sound-absorbing material is used, so there is less dirt and maintenance is unnecessary.

[0059] In the exterior wall structure 100 according to the second embodiment, sound waves diffracted by the protrusion tip 322 also enter the second exterior wall 210, but the double soundproofing structure of the first exterior wall 110 and the second exterior wall 210 sufficiently reduces noise propagating into the room. Also, although an example in which the protrusion 310 and the second exterior wall 210 are integrated is shown in Figures 9 and 10, the protrusion 310 and the second exterior wall 210 may be formed from separate members.

[0060] In the exterior wall structure 100 according to the second embodiment, if the inclination angle (θ3) of the protruding lower surface 311 is made larger than the angle perpendicular to the direction of noise arrival, the noise reflected by the protruding lower surface 311 is reflected in a direction further away from the building than the direction of arrival, and therefore does not enter the exterior of the building. Furthermore, if the effect of diffracted waves at the protruding tip 322 is small, the first exterior wall 110 can be omitted from the soundproofing structure.

[0061] Next, another embodiment of the exterior wall structure 100 according to the present invention will be described. Fig. 11 is a schematic diagram showing a modified example of the exterior wall structure 100 according to the second embodiment of the present invention. In this modified example, the second exterior wall upper end 221 and the overhang base end 321 can be arranged in approximately the same location. That is, the second exterior wall upper end 221 of the second exterior wall 210 can be structured to be connected to the overhang base end 321 of the overhang 310 on the upper floor. By adopting such a structure, theoretically, it is possible to reduce the overall width of the exterior wall structure 100 (in the left-right direction on the page) without providing a space for a large air layer 10, which has the advantage of making it easier to ensure space on the indoor side.

[0062] Next, differences between the embodiments will be described with reference to Fig. 12. In Fig. 12, solid lines indicate the second exterior wall 210 and the overhang 310 of the exterior wall structure 100 according to the second embodiment, and dashed lines indicate the second exterior wall 210 and the overhang 310 of the exterior wall structure 100 according to the first embodiment. The first exterior wall 110 is shown as being common. Note that in Fig. 12, in the case where the second exterior wall lower end 222 and the overhang tip 322 are connected, θ2 is equal to the angle between the second surface 211 (or the second back surface 212) of the second exterior wall 210 and the vertical plane.

[0063] 12, the exterior wall structure 100 according to the second embodiment, compared to the exterior wall structure 100 according to the first embodiment, can achieve a situation in which, when an air gap of the same width is secured between the first exterior wall 110 and the second exterior wall 210, the second exterior wall 210 is not directly exposed to sound waves even if the overhang 310 is small. The width of the air gap here refers to the width of the portion where the air gap is smallest in the horizontal position.

[0064] Next, with reference to FIG. 13, a technique common to the first and second embodiments will be described. In FIG. 13, the second exterior wall lower end 222 and the protruding tip 322 are connected, and θ2 is equal to the angle between the second surface 211 (or the second back surface 212) of the second exterior wall 210 and a vertical plane. The inclination angle (θ2) of the second surface 211 of the second exterior wall 210 of the exterior wall structure 100 according to the present invention can be changed depending on the number of floors of the building. As shown in FIG. 13, the incident angle (θ0) of sound waves (noise) on a given floor of the building changes depending on the number of floors. Accordingly, the inclination angle (θ2) of the second surface 211 of the second exterior wall 210 is set to be the same as the incident angle (θ0) of the sound waves (noise), and is also changed. Specifically, the inclination angle (θ2) of the second surface 211 of the front second exterior wall 210 is set to be smaller the higher the floor of the building. According to this embodiment, it is possible to implement noise reduction measures according to the floor of the building.

[0065] According to the exterior wall structure 100 of the second embodiment configured as described above, it is possible to enjoy the same effects as the exterior wall structure 100 of the first embodiment, and in addition, since there is no need to install a sound-absorbing processing section 340, it is possible to expect a sufficient noise reduction effect without the need for maintenance.

[0066] Furthermore, with the exterior wall structure 100 according to the second embodiment, soundproofing measures for the exterior of a building can be implemented without restricting the effective area of ​​the room.

[0067] Furthermore, with the exterior wall structure 100 according to the second embodiment, the exterior surface is not directly exposed to sound waves, making it possible to achieve quietness within the room. This effect can be achieved without reducing the effective area of ​​the room.

[0068] Furthermore, in the exterior wall structure 100 according to the second embodiment, the influence of diffracted waves is small, and if a soundproof structure is formed by omitting the first exterior wall 110, a larger effective area can be secured inside the room.

[0069] Furthermore, according to the exterior wall structure 100 of the second embodiment, the overhang 310 also functions as an eave that blocks sunlight, which has the effect of reducing the heat load on the building and saving energy.

[0070] Furthermore, the exterior wall structure 100 according to the second embodiment does not use any sound-absorbing material, so no maintenance is required and noise reduction effects can be expected across almost all frequency bands.

[0071] Furthermore, according to the exterior wall structure 100 of the second embodiment, it is possible to obtain a similar noise reduction effect compared to the invention of the first embodiment even if the width of the overhang 310 is small. [Explanation of symbols]

[0072] 1. Double skin structure 2. Inner skin 6. Outer skin 10. Air layer 100... External wall structure 110...1st outer wall 111...1st surface 112···First back side 210...Second outer wall 211...2nd surface 212···Second back side 221...Top end of second outer wall 222...lower end of second outer wall 310....Splash 311....Underside of protrusion 312....Top surface of protrusion 321....protruding base end 322....flip tip 340 Sound absorption processing section

Claims

1. An exterior wall structure of a building, a first exterior wall disposed on the indoor side; A second exterior wall disposed on the outdoor side of the first exterior wall; a projection disposed so as to project from the first exterior wall to the exterior side, The angle between the plane connecting the upper end of the second outer wall and the tip of the protrusion and the vertical plane is θ 2 year, The angle between the direction in which the sound wave enters the building and the vertical plane is θ 0 Then, i 2 ≧θ 0 The exterior wall structure has the following relationship.

2. 2. The exterior wall structure according to claim 1, wherein the lower surface of the protrusion is parallel to a horizontal plane.

3. 3. The exterior wall structure according to claim 1, wherein the lower surface of the protrusion is treated to absorb sound.

4. The angle between the vertical plane and the direction in which the sound waves enter the building is θ 0 Then, θ 2 = θ 0 The exterior wall structure according to claim 1 or 2, wherein:

5. θ 2 The exterior wall structure according to claim 1 or 2, wherein the higher the floor of the building, the smaller the

6. The angle between the lower surface of the protrusion and the horizontal plane is θ 3 Then, θ 3 = θ 0 The exterior wall structure according to claim 1 .

7. The angle between the lower surface of the protrusion and the horizontal plane is θ 3 Then, θ 2 = θ 3 The exterior wall structure according to claim 1 .

8. The outer wall structure according to claim 6 or 7, wherein an upper end of the second outer wall and a base end of the protrusion are disposed at substantially the same location.

9. θ 2 The exterior wall structure according to claim 6 or claim 7, wherein the higher the floor of the building, the smaller the width of the wall.

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