JP2015114635A - Sound block structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sound block structure which is light and thin.SOLUTION: The sound block structure of the invention blocks transmission of incident sound from one surface to the other surface side, out of a first surface and a second surface. The sound block structure has a hollow interior space, and the first surface part and second surface part comprise: a frame having plural openings communicated to the interior space; and a flexible film covering all openings on the first surface part and the second surface part and defining the interior space from an external space. The interior space is decompressed to pressure less than air pressure, therefore a part above the opening parts on the film enters the interior space in a curve state, and tension is applied to the film, namely it becomes a decompressed state.

Description

  The present invention relates to a sound insulation structure. More specifically, the present invention relates to a sound insulation structure that obtains excellent sound insulation by applying tension to a thin film.

  In general, the sound insulation structure is configured based on the mass law and the rigidity side. The mass rule is that the greater the surface density, which is the mass per unit area of the sound insulation structure, the higher the sound insulation effect. This is because a sound insulation structure having a higher surface density has a higher transmission loss when passing through the sound insulation structure. On the other hand, the rigidity law is that the higher the rigidity of the sound insulation structure, the higher the sound insulation effect. Here, the stiffness law is an idea for very low frequency sound, and the mass law is considered to be dominant in most of the audible frequency range.

  Therefore, the sound insulation structure for the purpose of sound insulation in a normal audible frequency region is designed to increase the sound insulation effect by increasing the surface density of the sound insulation structure according to the mass law. However, in order to increase the sound insulation effect by the mass law, it is necessary to increase the thickness of the sound insulation structure, so that there is a problem that the sound insulation structure becomes large and heavy.

  For such a problem, Patent Document 1 discloses a sound absorbing structure in which a frame having a plurality of air chambers in an in-plane direction has an opening on one side and the opening is closed with a thin film. Yes. By applying tension according to the main frequency of the sound to be sound-absorbed to the thin film, a sound-absorbing structure having a small required space and excellent sound-absorbing characteristics can be configured.

  Patent Document 2 describes a sound insulation structure in which a bag-like thin film is sandwiched between frames having a plurality of openings from both sides. And it is supposed that the sound insulation effect can be obtained by filling the bag-like film with air until the film projects into the opening of the frame. Thereby, it is supposed that it can be set as the sound insulation structure of a lightweight and cheap structure.

JP-A-8-50489 JP 2012-122236 A

  However, the sound absorbing structure described in Patent Document 1 is a film in which one surface is constituted by a part of the frame, while the other surface located on the opposite side blocks the opening of the frame. It is constituted by. That is, the film to which tension is applied is provided only on one surface, and further, there is a difference in strength due to the different materials on the front and back surfaces of the sound absorbing structure. As described above, since the front and back structures are asymmetric, there is a problem that the sound absorbing structure is warped when tension is applied to the film.

  On the other hand, since the sound insulation structure described in Patent Document 2 has a structure in which a bag-like film is sandwiched between both sides by a frame, there is no difference in strength between the front and back surfaces as in Patent Document 1. Has the structure. However, since the bag-like film is sandwiched between the frames from both sides, the frames are fixed only at the outer edge portions and cannot be fixed to each other near the center. This is because there is a film for sound insulation between the center of the frames on both sides. For this reason, in the vicinity of the center of the frame body, the frame bodies are deformed so as to move away from each other due to the pressing force when air is filled in the bag-like film. The amount of deformation near the center of the frame increases as the area of the sound insulation structure increases, compared to the outer edge. This is because the greater the area of the sound insulation structure, the greater the distance from the fixed outer edge near the center of the frame.

  Note that both the warp of the sound absorbing structure according to Patent Document 1 and the deformation of the sound insulating structure according to Patent Document 2 near the center of the frame are reduced by increasing the strength of the frame and the frame, for example. can do. However, in order to increase the strength, the sound absorbing structure and the sound insulating structure are large and heavy as a whole, which is not preferable.

  The present invention has been made for the purpose of solving the problems of the prior art described above. That is, the subject is to provide a lightweight and thin sound insulation structure.

  The sound insulation structure of the present invention made for the purpose of solving this problem has a first surface and a second surface opposite to the first surface, and one of the first surface and the second surface. A sound insulation structure that blocks transmission of incident sound to the other surface side, and includes a first surface portion located on the first surface side and a second surface portion located on the second surface side , A hollow internal space is formed inside, a frame in which a plurality of openings connected to the internal space are formed in both the first surface portion and the second surface portion, and all of the first surface portion and the second surface portion. And a flexible film that divides the internal space from the external space, and the internal space is depressurized to a pressure lower than atmospheric pressure, so that the portion above the film opening is internal. It must enter a curved state toward the space and take a reduced pressure state with tension applied to the film. A sound insulating structure according to claim.

  The sound insulation structure of the present invention has films on both the first surface and the second surface. In the reduced pressure state, tension is applied to the films on the first surface and the second surface. In the state where the film is under tension, the transmission loss of the sound insulation structure increases, and the sound insulation effect is exhibited. Moreover, since it is the structure which has a film in both 1st surface and 2nd surface, the tensile force by the tension | tensile_strength of a film is equally applied to the 1st surface part and 2nd surface part of a flame | frame. For this reason, the frame will not bend. Further, in the reduced pressure state, the inner space is reduced in pressure, so that the frame existing between the films on the first surface and the second surface receives a compressive load in the thickness direction. However, the compressive load received by the frame is almost uniform at the outer edge and near the center. Therefore, the strength of the frame may be the same at the outer edge and near the center. For this reason, it can be set as the lightweight sound insulation structure thin regardless of the area of sound insulation object.

  Further, in the sound insulation structure described above, an exhaust portion that performs an exhaust operation for exhausting the air in the internal space to the outside, a ventilation state that allows air flow between the outside and the internal space, and a non-permeable air that does not allow It is preferable to have a ventilation part that takes a state, and to be able to take a decompressed state and a non-depressurized state in which the decompression of the internal space is released. The sound insulation structure is in a sound insulation state with a large transmission loss in a reduced pressure state, and is in a non sound insulation state with a small transmission loss in a non-decompression state. Therefore, the sound insulation structure can be switched between the sound insulation state and the non-sound insulation state by being able to take the decompression state and the non-decompression state.

  Moreover, the sound insulation structure described above may be one that is maintained in a reduced pressure state. This is because the sound insulation state can always be maintained by maintaining the reduced pressure state.

  In the sound insulation structure described above, the frame includes the first surface portion and the second surface portion as separate parts, and is disposed between the first surface portion and the second surface portion. It is good also as having a connection member which connects two surface parts at intervals. This is because there is no change in that the sound insulation structure can be made lightweight and thin.

  In the sound insulation structure described above, it is preferable that the first surface portion and the second surface portion have different natural frequencies. When the first surface portion and the second surface portion have the same natural frequency, the transmission loss of the sound insulation structure is reduced in a certain frequency band. On the other hand, it is possible to prevent a decrease in transmission loss in a certain frequency band by the configuration in which the natural frequency is different between the first surface portion and the second surface portion.

  Moreover, in the sound insulation structure described above, the film may be a bag shape that accommodates the entire frame, and the film and the frame may not be joined. This is because there is no change in that the sound insulation structure can be made lightweight and thin.

  In the sound insulation structure described above, the film may include a first film that covers only a part of the openings in the frame and a second film that covers the opening that is not covered by the first film. The first film and the second film are both joined to the frame at the annular portion including all the openings covered by each of the first film and the second film, and are not joined to the frame inside the annular portion. Is preferred. When the pressure is reduced, the film extends at a position inside the annular portion, and a portion on each opening enters the internal space. Thereby, the contact location of the film with respect to the edge of each opening part can be changed with the fall of the pressure of internal space at the time of being made into a pressure reduction state. Therefore, the concentration of fatigue due to the film being pressed against the edge of each opening can be alleviated and the life of the film can be extended.

  In the sound insulation structure described above, each of the first surface portion and the second surface portion has a first outer member and a second outer member provided outside the film, and the first outer member and the second outer member are provided. Each of the outer members has a convex portion at a position corresponding to the opening portion on the surface facing the frame, and a position between the convex portion and the convex portion is a groove-like portion. It is preferable that at least the pressure contact state between the pressure contact state pressed against the frame so as to enter the opening and the non-pressure contact state where pressure contact is released is taken. This is because in the pressure contact state, the film can be tensioned by the convex portion.

  In the sound insulation structure described above, the entry height from the opening of the convex portion in the pressure contact state to the inner space is the entry height from the opening of the portion on the opening of the film in the reduced pressure state to the inner space. It is preferable that it is lower than this. This is because even if the reduced pressure state cannot be maintained, the film can be tensioned by setting the pressure contact state. This is because the sound insulation state can be maintained.

  In the sound insulation structure described above, it is preferable that the curvature radius of the surface of the convex portion when in the pressure contact state is larger than the curvature radius of the portion on the opening portion of the film in the reduced pressure state. This is because the concentration of stress on the film by the convex portion can be reduced and the life of the film can be extended.

In the sound insulating structure described above, the frame is preferably made of a material having viscoelasticity. This is because the adhesion between the film and the frame can be improved. In addition, the transmission loss of the frame itself can be increased. Further, even when some air enters the internal space from the outside in a reduced pressure state, the frame that is compressed in the direction perpendicular to the first surface and the second surface due to a compressive load is This is because the tension of the film can be maintained by stretching.

  In the sound insulation structure described above, it is preferable that the opening has a chamfered edge portion. This is because the rounded chamfering process and 45 ° chamfering process are applied to the edge of the opening, so that the stress concentration when the film is pressed against the opening can be alleviated and the life of the film can be extended. .

  In the sound insulation structure described above, it is preferable that at least the film of the film and the frame is transparent or translucent. This is because the visibility on the other surface side from the one surface side of the first surface and the second surface can be ensured.

  According to the present invention, a lightweight and thin sound insulation structure is provided.

It is sectional drawing of the sound insulation structure which concerns on a 1st form. It is a front view of the sound insulation structure concerning a 1st form. It is the graph which showed the transmission loss of the sound insulation structure for every pressure of internal space. It is sectional drawing of the sound insulation structure which concerns on a 2nd form. It is a front view of the sound insulation structure concerning a 2nd form. It is a figure which shows an example of the shape of a frame. It is a figure which shows the example of the pattern of the frame different from FIG. It is the graph which showed the transmission loss of the sound insulation structure at the time of using a frame of a different natural frequency. It is sectional drawing which shows when the press-contact member is a non-pressure-contact state of the sound insulation structure which concerns on a 3rd form. It is sectional drawing which shows the time of the pressure-contact member of the sound insulation structure which concerns on a 3rd form in a pressure-contact state.

[First embodiment]
Hereinafter, a first embodiment of the present invention will be described in detail with reference to the accompanying drawings. In FIG. 1, sectional drawing of the sound-insulation structure 1 which concerns on this form is shown. FIG. 2 is a front view of the sound insulation structure 1. The sound insulation structure 1 according to the present embodiment can block the transmission of incident sound to one surface of the first surface A on the left side and the second surface B on the right side in FIG. 1 to the other surface side. It is.

  As shown in FIG. 1, the sound insulation structure 1 includes a frame 20 and films 10 and 11 attached to a surface 21 on the first surface A side and a surface 22 on the second surface B side of the frame 20, respectively. Have. Both films 10 and 11 are flexible thin films. As the films 10 and 11, a resin film made of polyethylene or vinyl chloride can be used.

As shown in FIG. 2, the frame 20 of the present embodiment is configured such that an outer wall 28 that forms upper, lower, left, and right side surfaces and an inner wall 26 provided inside the outer wall 28 intersect in a lattice pattern. . Further, as shown in FIG. 2, a portion of a grid formed by the inner wall 26 and the outer wall 28 of the surface 21 of the frame 20 intersecting in a lattice form is an opening 23. On the surface 22 opposite to the surface 21 of the frame 20, the grids formed by the inner wall 26 and the outer wall 28 intersecting in a lattice form are openings 24 (FIG. 1). An internal space 25 is formed inside the openings 23 and 24 of the frame 20.

  Further, as shown in FIGS. 1 and 2, a through hole 27 is formed in the inner wall 26. Through the through holes 27, the internal space 25 of the frame 20 is in communication with each other to form one space. Note that the outer wall 28 is not formed with a through hole like the inner wall 26. As the material of the frame 20, metal, resin, rubber, or the like can be used.

  In the sound insulation structure 1, the films 10 and 11 cover all the openings 23 and 24 of the surfaces 21 and 22 of the frame 20, respectively. The films 10 and 11 are joined to the frame 20 only at the outer edge portion. That is, the films 10 and 11 are joined only to the portion constituting the outer wall 28 of the surfaces 21 and 22 of the frame 20 and are not joined to the portion constituting the inner wall 26. The films 10 and 11 partition the internal space 25 of the frame 20 from the outside of the sound insulation structure 1. FIG. 2 shows a square frame 20 in which the openings 23 and 24 have a square shape. However, the shape of the openings 23 and 24 is not limited to a square, but may be a rectangle, a rhombus, or a parallelogram. Alternatively, it may be a triangle or a hexagon.

  Further, an exhaust pump 30, a pressure detection unit 31, and an intake valve 32 are provided on the right outer wall 28 in FIG. 2 of the frame 20 of the sound insulation structure 1. In addition, the exhaust pump 30, the pressure detection unit 31, and the intake valve 32 are all connected to the control unit 33.

  The exhaust pump 30 is for discharging the air in the internal space 25 of the frame 20 to the outside of the sound insulation structure 1 in accordance with an instruction from the control unit 33. The pressure detection unit 31 is a sensor for detecting the pressure in the internal space 25. The pressure detector 31 detects a gauge pressure that is the difference between the absolute pressure and the atmospheric pressure, and outputs the detected value to the controller 33.

  The intake valve 32 is a valve for allowing air to flow into the internal space 25 from the outside of the sound insulation structure 1. The intake valve 32 is normally closed, and air does not flow into the internal space 25 from the outside. In response to an instruction from the control unit 33, the intake valve 32 is opened, and the internal space 25 and the outside communicate with each other. At this time, when the pressure in the internal space 25 is less than atmospheric pressure, air flows into the internal space 25 from the outside.

  In the sound insulation structure 1 of the present embodiment, the sound insulation structure 1 can be switched between a sound insulation state in which the sound insulation structure 1 hardly transmits sound and a non-sound insulation state in which sound is almost transmitted by adjusting the pressure in the internal space 25. . Specifically, when the pressure in the internal space 25 is in a non-depressurized state where the pressure is substantially the same as the atmospheric pressure, the sound insulating structure 1 is in a non-sound insulating state. When the sound insulation structure 1 is not decompressed, the control unit 33 opens the intake valve 32.

  In the sound insulation structure 1 in the non-depressurized state, since the pressure in the internal space 25 is substantially the same as the atmospheric pressure, the films 10 and 11 are not pressed against the surfaces 21 and 22 of the frame 20, respectively. That is, the films 10 and 11 in the sound insulation structure 1 in the non-depressurized state are in a state indicated by a solid line in FIG. 1 and are in a state where no special tension is applied. The sound insulation structure 1 in the non-depressurized state is in a non-sound insulation state in which sound incident on one surface of the first surface A and the second surface B can be transmitted almost to the other surface side.

  On the other hand, the sound insulation structure 1 is in a sound insulation state when the pressure in the internal space 25 is a reduced pressure state that is a negative pressure less than atmospheric pressure. When the sound insulation structure 1 is brought into a reduced pressure state, the control unit 33 closes the intake valve 32 and exhausts the air in the internal space 25 by the exhaust pump 30. Specifically, the control unit 33 determines the amount of air discharged from the internal space 25 by the exhaust pump 30 so that the pressure of the internal space 25 detected by the pressure detection unit 31 becomes a preset pressure that is less than atmospheric pressure. Adjust.

  The films 10 and 11 of the sound insulation structure 1 in the reduced pressure state are pressed against the surfaces 21 and 22 of the frame 20 because the internal space 25 is negative pressure. Furthermore, in the sound insulation structure 1 in the reduced pressure state, as shown by a two-dot chain line in FIG. 1, the central portion of each opening 23, 24 of the films 10, 11 has a shape protruding into the internal space 25. . For this reason, tension is applied to the films 10 and 11 in the reduced pressure state.

  And the sound insulation structure 1 of the pressure reduction state by which the tension | tensile_strength is applied to the films 10 and 11 is a thing with a large transmission loss. This is because the sound air conduction is reduced in the internal space 25 in a decompressed state. Furthermore, because the tension is applied to the films 10 and 11, the vibration of the frame 20 is suppressed. Therefore, the sound insulation structure 1 in the reduced pressure state is in a sound insulation state in which the incident sound on one surface of the first surface A and the second surface B is hardly transmitted to the other surface side. Note that the thickness of the frame 20 in the left-right direction in FIG. 1 is such that the films 10 and 11 that have entered the internal space 25 of the frame 20 do not contact each other in a decompressed state.

  Further, in the sound insulation structure 1 in a reduced pressure state, the tension is applied to the films 10 and 11, so that the inner wall 26 and the outer wall 28 of the frame 20 are subjected to a lateral compressive load in FIG. 1. However, the frame 20 hardly deforms due to the compressive load. This is because the compressive load received by the inner wall 26 and the outer wall 28 of the frame 20 in the decompressed state is not a load that causes the inner wall 26 and the outer wall 28 to yield. Further, the frame 20 has the films 10 and 11 attached to the surfaces 21 and 22 located on the front and back surfaces of each other, and has a symmetrical structure with respect to the left and right in FIG. This is because the tensions of the films 10 and 11 in the reduced pressure state are equally applied to the surfaces 21 and 22 of the frame 20 symmetrically.

  Further, the deformation amount of only a part of the frame 20 does not increase in the decompressed state. This is because the compressive load received by the frame 20 is not a load that yields the inner wall 26 and the outer wall 28, and the loads applied to the inner wall 26 and the outer wall 28 are substantially the same. For this reason, for example, only the inner wall 26 located at the center of the surfaces 21 and 22 of the frame 20 is not greatly deformed. Therefore, when the frame 20 having a large area of the surfaces 21 and 22 in FIG. 2 is adopted, the thickness of the inner wall 26 of the portion is increased in order to increase the rigidity of the central portion of the large surfaces 21 and 22. There is no need to make it thicker than other parts. That is, the sound insulation structure 1 can be light and thin regardless of the area of the sound insulation object.

  Moreover, in the sound insulation structure 1 of this embodiment, the films 10 and 11 are joined to the frame 20 only at the outer edge portions. When switching from the non-depressurized state to the depressurized state, the films 10 and 11 are stretched as a whole, and the portions on the openings 23 and 24 enter the internal space 25 of the frame 20. Further, the protruding amount of the portions on the openings 23 and 24 of the films 10 and 11 into the internal space 25 gradually increases as the pressure in the internal space 25 decreases. For this reason, the contact part of the films 10 and 11 with respect to the edge of each opening part 23 and 24 changes gradually with the fall of the pressure of the internal space 25 at the time of switching from a non-decompression state to a decompression state. That is, the stress due to the edges of the openings 23 and 24 does not remain on the same portion of the films 10 and 11. Thereby, the concentration of fatigue due to the films 10 and 11 being pressed against the edges of the openings 23 and 24 can be alleviated, and the life of the films 10 and 11 can be extended.

  Further, the edges of the openings 23 and 24 of the frame 20 are preferably subjected to round chamfering or 45 ° chamfering. This is because the stress concentration when the films 10 and 11 are pressed against the openings 23 and 24 of the films 10 and 11 in a reduced pressure state can be relaxed, and the life of the films 10 and 11 can be extended. Furthermore, it is because the adhesiveness to the opening parts 23 and 24 of the films 10 and 11 can be improved.

  The material of the frame 20 of the sound insulation structure 1 is preferably a material having viscoelasticity. That is, it is preferable that the frame 20 has a property of being deformed to some extent by an external force when an external force is applied and returning to its original shape when the external force is removed. This is because when the frame 20 has viscoelasticity, the adhesion between the films 10 and 11 and the frame 20 in a reduced pressure state can be improved. Further, in the sound insulation structure 1 of the present embodiment, the incident sound on one of the first surface A and the second surface B can be transmitted to the other surface side through the inner wall 26 and the outer wall 28 of the frame 20. is there. This is because the transmission loss can be increased by virtue of the viscoelasticity of the inner wall 26 and the outer wall 28 against such transmitted sound.

  Further, the inner wall 26 and the outer wall 28 having viscoelasticity are contracted in the left-right direction in FIG. This is because it receives a compressive load as described above. When some air enters the internal space 25 in a decompressed state from the outside of the sound insulation structure 1, the shrunken inner wall 26 and outer wall 28 extend by the amount of the entered air. This is because the tension of the films 10 and 11 can be maintained even when some air enters the internal space 25 in a decompressed state, and the sound insulation effect can be prevented from being lowered.

  Further, the films 10 and 11 and the frame 20 are preferably transparent or translucent. This is because the visibility on the other side of the sound insulation structure 1 from the one side of the first surface A and the second surface B of the sound insulation structure 1 can be ensured.

  In the sound insulation structure 1 of this embodiment, the transmission loss can be adjusted by adjusting the pressure in the internal space 25. FIG. 3 shows the result of measuring transmission loss for each pressure in the internal space 25 of the sound insulation structure 1. FIG. 3 is obtained by the sound insulation structure 1 using a polyethylene film having a thickness of 10 μm as the films 10 and 11 and aluminum having hexagonal aluminum openings 23 and 24 as the frame 20. Further, the frame 20 was used with the number of openings 23 and 24 on the surfaces 21 and 22 being 1200 per square inch.

  In FIG. 3, the horizontal axis represents frequency and the vertical axis represents transmission loss. Further, in FIG. 3, a case where the pressure in the internal space 25 is atmospheric pressure is indicated by a two-dot chain line, a case where the pressure is weak negative pressure is indicated by a broken line, and a case where the pressure is strong negative pressure is indicated by a solid line. The weak negative pressure was 0.9 atm, and the strong negative pressure was 0.8 atm. That is, in FIG. 3, the two-dot chain line indicates the transmission loss of the sound insulation structure 1 in the non-depressurized state, and the broken line and the solid line indicate the transmission loss of the sound insulation structure 1 in the reduced pressure state.

  As shown in FIG. 3, the transmission loss of the sound insulation structure 1 in the non-depressurized state where the pressure in the internal space 25 is atmospheric pressure is small regardless of the sound frequency. That is, it can be seen that the sound insulation structure 1 in the non-depressurized state is hardly insulated. In addition, as shown in FIG. 3, the transmission loss of the sound insulation structure 1 in the reduced pressure state where the pressure in the internal space 25 is negative is greater in all frequency bands than the transmission loss of the sound insulation structure 1 in the non-decompression state. Recognize.

  Furthermore, it can be seen from FIG. 3 that the sound insulation structure 1 has a larger transmission loss and a higher sound insulation effect when the pressure in the internal space 25 is a strong negative pressure than when the pressure in the inner space 25 is a weak negative pressure. That is, it can be seen that the sound insulation structure 1 can adjust the transmission loss by adjusting the pressure in the internal space 25. In the results shown in FIG. 3, the transmission loss of the sound insulation structure 1 is reduced in the frequency band indicated by X in the figure in both cases where the pressure in the internal space 25 is low and low. However, even in the frequency band indicated by X, the transmission loss is larger in the decompressed state than in the non-decompressed state, and the sound insulation effect is maintained high.

  As described above in detail, the sound insulation structure 1 includes the frame 20 and the films 10 and 11 covering the openings 23 and 24 on both surfaces of the surfaces 21 and 22 of the frame 20, respectively. Further, when the pressure is reduced, the films 10 and 11 are tensioned by the portions on the openings 23 and 24 projecting toward the internal space 25. In such a reduced pressure state, the sound insulation structure 1 has a large transmission loss. Therefore, a lightweight and thin sound insulation structure is realized.

  Note that this embodiment is merely an example, and does not limit the present invention. Therefore, the present invention can naturally be improved and modified in various ways without departing from the gist thereof. For example, in the above embodiment, a configuration in which only the outer edge portions of the films 10 and 11 are joined to the surfaces 21 and 22 of the frame 20, respectively, has been described. However, the films 10 and 11 may be bonded around the openings 23 and 24 of the surfaces 21 and 22, for example. Alternatively, the film may be a bag that covers the frame 20. In this case, the bag-shaped film and the frame 20 may not be joined.

  In addition, for example, when it is used in a sound-insulated state at all times, it is manufactured by being sealed in a pressure-reduced state in which the pressure of the internal space 25 is set to a set pressure, and the exhaust pump 30, the pressure detector 31, the intake valve 32, and the control. The part 33 and the like may be omitted.

[Second form]
The second embodiment will be described. The sound insulation structure according to this embodiment is different from the first embodiment in the frame configuration. Specifically, the sound insulation structure of the present embodiment is configured such that two mesh-like frames with a film attached to one side are mutually supported by a frame support on a surface opposite to the surface to which the film is attached. It is the thing of the structure formed by connecting.

  A cross-sectional view of the sound insulation structure 100 according to the second embodiment is shown in FIG. FIG. 5 is a front view of the sound insulation structure 100. Similarly to the first embodiment, the sound insulation structure 100 according to the present embodiment transmits sound incident on one surface of the first surface A on the left side and the second surface B on the right side in FIG. Can be cut off.

  As shown in FIG. 4, the sound insulation structure 100 includes a frame 150 including frames 120 and 130 and a frame connecting portion 140, and films 110, 111, and 112. Also in this embodiment, the films 110, 111, and 112 are all thin films having flexibility. As the films 110, 111, and 112, resin films made of polyethylene, vinyl chloride, or the like can be used.

  The frame 150 of this embodiment includes a frame body 120 that forms the surface 151 on the first surface A side, and a frame body 130 that forms the surface 152 on the second surface B side. Both the frames 120 and 130 have a thickness that is the length in the left-right direction in FIG. 4 that is thinner than the entire thickness of the frame 150. Further, both the frame bodies 120 and 130 have a mesh shape as shown in the front view of FIG.

  That is, as shown in FIG. 5, the through-holes 121 and 131 are formed in the frames 120 and 130 at the same positions in the front view, respectively. And the opening part of the left side in FIG. 4 of the through-hole 121 of the frame 120 is the opening part 153 of the flame | frame 150 opened to the surface 151 of the 1st surface A side. Further, the opening on the right side in FIG. 4 of the through hole 131 of the frame 130 is the opening 154 of the frame 150 that opens to the surface 152 on the second surface B side.

  As shown in FIG. 4, the frame body 120 and the frame body 130 face each other on the surface opposite to the surfaces constituting the surfaces 151 and 152 of the frame 150 and are provided at intervals. ing. The frame body connecting portion 140 is a member that connects the frame body 120 and the frame body 130 to each other in a state where the surfaces facing each other are spaced apart from each other.

  It is preferable that the frame connecting portions 140 are provided at the four corners of the frame bodies 120 and 130 in FIG. In the frame 150 of the present embodiment, as shown in FIGS. 4 and 5, the frame body connecting portions 140 are provided at a plurality of locations in the intersections of the meshes of the frame bodies 120 and 130 in addition to the four corners. The frame connecting portion 140 may be provided at all the intersections of the meshes of the frame bodies 120 and 130.

  Therefore, in the frame 150 of this embodiment, the internal space 155 is formed between the frame body 120 and the frame body 130. The internal space 155 communicates with the opening 153 of the surface 151 of the frame 150 and the opening 154 of the surface 152. Also in this embodiment, metal, resin, rubber, or the like can be used as the material of the frame bodies 120 and 130 and the frame body connecting portion 140 constituting the frame 150.

  Also in the sound insulation structure 100 of this embodiment, films 110 and 111 are attached to the surface 151 on the first surface A side and the surface 152 on the second surface side of the frame 150, respectively. Each of the films 110 and 111 is bonded to the frame 150 only at the outer edge portion. Thereby, all the openings 153 and 154 of the surfaces 151 and 152 of the frame 150 are covered with the films 110 and 111, respectively. 5 shows a frame in which the shapes of the openings 153 and 154 are square, but the shape is not limited to a square, and may be a rectangle, a rhombus, or a parallelogram. Alternatively, it may be a triangle or a hexagon. Further, the upper, lower, left and right surfaces of the frame 150 in FIG. 5 are all closed by the film 112 being bonded.

  In addition, the right side film 112 of the sound insulation structure 100 in FIG. 5 is provided with an exhaust pump 30, a pressure detection unit 31, and an intake valve 32. In addition, the exhaust pump 30, the pressure detection unit 31, and the intake valve 32 are all connected to the control unit 33.

  Also in this embodiment, the sound insulation structure 100 can be switched between the sound insulation state and the non-sound insulation state by adjusting the pressure in the internal space 155. Specifically, when the intake valve 32 is in the non-depressurized state with the open state, the sound insulation structure 100 is in the non-sound insulation state. Also in the sound insulation structure 100 in the non-depressurized state, the films 110 and 111 are in a state indicated by a solid line in FIG. 4 and are in a state where no special tension is applied.

  On the other hand, when the intake valve 32 is closed and the exhaust pump 30 exhausts the air in the internal space 155 to reduce the pressure, the sound insulation structure 100 is in a sound insulation state. The films 110 and 111 of the sound insulation structure 100 in the reduced pressure state are pressed against the surfaces 151 and 152 of the frame 150 because the internal space 155 has a negative pressure. Furthermore, in the sound insulation structure 100 in the reduced pressure state, as shown by a two-dot chain line in FIG. 4, the central portions of the openings 153 and 154 of the films 110 and 111 are projected into the internal space 155. For this reason, tension is applied to the films 110 and 111 in the reduced pressure state. Also in this embodiment, in the left-right direction in FIG. 4, the total thickness of the frame 150 including the thickness of the frame bodies 120 and 130 and the length of the frame body connection portion 140 is reduced to the internal space 155 in the decompressed state. The thickness is such that the film 110 and 111 that have penetrated do not come into contact with each other.

  In the sound insulation structure 100 in the sound insulation state, the tension is applied to the films 110 and 111, so that the frame connection part 140 of the frame 150 receives a compressive load in the horizontal direction in FIG. However, the frame 150 hardly deforms due to the compressive load. This is because the compressive load received by the frame body connecting portion 140 of the frame 150 in the reduced pressure state is not a load that yields the frame body connecting portion 140. Also, the frame 150 has the films 110 and 111 attached to the surfaces 151 and 152 that are positioned on the front and back sides, and has a symmetrical structure with respect to the left and right in FIG. Furthermore, even in the sound insulating structure 100, the deformation amount of only a part of the frame 150 does not increase in a decompressed state. This is because the compressive load received by the frame 150 is not a load that yields the frame connecting portion 140, and the load applied to each frame connecting portion 140 is substantially the same. That is, the sound insulation structure 100 can be light and thin regardless of the area of the sound insulation object.

  Also in the sound insulation structure 100 of this embodiment, the films 110 and 111 are joined to the frame 150 only at the outer edge portions. For this reason, when the non-depressurized state is switched to the depressurized state, the contact location of the films 110 and 111 with respect to the edges of the openings 153 and 154 changes as the pressure in the internal space 25 decreases. Therefore, the concentration of fatigue on the films 110 and 111 can be alleviated and the life of the films 110 and 111 can be extended. Further, the edges of the openings 153 and 154 of the frame 150 are preferably subjected to round chamfering or 45 ° chamfering. This is because the life of the films 110 and 111 can be extended and the adhesion of the films 110 and 111 to the openings 153 and 154 can be enhanced.

  Moreover, it is preferable that the materials of the frame bodies 120 and 130 and the frame body connection portion 140 constituting the frame 150 of the sound insulation structure 100 are viscoelastic. This is because the frames 120 and 130 have viscoelasticity, whereby the adhesion between the films 110 and 111 and the frame 150 in the sound insulation state can be improved. Moreover, it is because the transmission loss of a transmitted sound can be enlarged because the frame connection part 140 has viscoelasticity. Furthermore, the frame connecting portion 140 having viscoelasticity is in a contracted state in the length direction in the left-right direction in FIG. Therefore, even if some air enters the internal space 155 in a reduced pressure state, the tension of the films 110 and 111 can be maintained, and the sound insulation effect can be prevented from being lowered.

  Furthermore, the films 110 and 111 and the frame 150 are preferably transparent or translucent. This is because the visibility on the other side of the sound insulation structure 100 from the one side of the first surface A and the second surface B of the sound insulation structure 100 can be ensured.

  Also in the sound insulation structure 100 of the present embodiment, the transmission loss can be adjusted by adjusting the pressure in the internal space 155 as in the first embodiment. Furthermore, in the sound insulation structure 100 of this embodiment, the sound insulation effect can be improved by using frames 120 and 130 of the frame 150 having different natural frequencies.

  6 and 7 are examples of the frame bodies 120 and 130 having different natural frequencies. 6 and 7 are views showing the respective frames as viewed from the front, and are views as seen from the same direction as FIG. FIG. 6 and FIG. 7 have different natural frequencies because the size and number of openings and the mesh thickness are different. For example, the frame shown in FIG. 6 can be used as the frame body 120, and the one shown in FIG. 7 can be used as the frame body 130. Further, in this case, the frame connecting portion 140 is provided at a location where the mesh of the frame 120 in FIG. 6 and the mesh of the frame 130 in FIG. 7 overlap in addition to the four corners of the frames 120 and 130. Good.

  In FIG. 8, the result of measuring the transmission loss when using the frame 120 shown in FIG. 6 and the frame 130 shown in FIG. 7 is shown by a solid line. Further, in FIG. 8, the transmission loss between the case where the frame body 120, 130 is the same as that of FIG. 6 and the case where the frame body 120, 130 is the same as that of FIG. This is indicated by a chain line. In any case, the configuration is the same except for the shapes of the frame bodies 120 and 130. That is, the number of places where the frame body connecting portion 140 is provided is the same.

  As shown in FIG. 8, when both the frame bodies 120 and 130 are the same as those in FIG. 6, the transmission loss is low in the frequency band indicated by Y. Further, when both the frames 120 and 130 are the same as those shown in FIG. 7, the transmission loss is low in a frequency band indicated by Z different from Y. That is, when both the frame bodies 120 and 130 are those shown in FIG. 6 or FIG. 7, it can be seen that the sound insulation effect is reduced for the sound in the Y or Z frequency band.

  On the other hand, when the frames 120 and 130 shown in FIGS. 6 and 7 are used, the transmission loss does not decrease so much even in the Y or Z frequency band. That is, it can be seen that by using the frames 120 and 130 having different natural frequencies, the sound insulation structure 100 having a high transmission loss and a high sound insulation effect in all frequency bands can be obtained. Naturally, the modes of the frames 120 and 130 having different natural frequencies are not limited to the examples shown in FIGS. For example, even if the shape and material of the opening are different, the frames 120 and 130 having different natural frequencies can be used.

  As described above in detail, the sound insulation structure 100 includes the frame 150 having a structure different from that of the first embodiment. The frame 150 is formed by connecting two mesh-shaped frame bodies 120 and 130 by a frame body connecting portion 140. Films 110 and 111 are attached to the surfaces 151 and 152 of the frame 150 where the openings 153 and 154 are formed. In the decompressed state, the films 110 and 111 are tensioned by the portions on the openings 153 and 154 projecting toward the internal space 155. In such a reduced pressure state, the sound insulation structure 100 has a large transmission loss. Therefore, a lightweight and thin sound insulation structure is realized.

  Note that this embodiment is merely an example, and does not limit the present invention. Therefore, the present invention can naturally be improved and modified in various ways without departing from the gist thereof. For example, in the above-described embodiment, a configuration in which only the outer edge portions of the films 110 and 111 are joined to the surfaces 151 and 152 of the frame 150 has been described. However, the films 110 and 111 may be bonded around the openings 153 and 154 of the surfaces 151 and 152, for example. Alternatively, the film may be a bag that covers the frame 150. In this case, the bag-like film and the frame 150 may not be joined.

  In addition, for example, when it is used in a sound-insulated state at all times, it is manufactured by being sealed in a pressure-reduced state in which the pressure of the internal space 155 is set to a set pressure, and the exhaust pump 30, the pressure detector 31, the intake valve 32, and the control The part 33 and the like may be omitted. Further, for example, the frame 150 of the present embodiment is formed by joining the frame bodies 120 and 130 by a plurality of columnar frame body connection portions 140. However, the shape of the frame connecting portion 140 is not limited to a columnar shape, and may be a plate shape, for example.

[Third embodiment]
A third embodiment will be described. The sound insulation structure according to the present embodiment is different from the first embodiment in that it includes pressure contact members that are pressed against the first surface and the second surface, respectively. The pressure contact member has a convex portion on a surface facing the first surface and the second surface, and tension can be applied to the film by the convex portion.

  A cross-sectional view of the sound insulation structure 200 according to the third embodiment is shown in FIG. As shown in FIG. 9, the sound insulation structure 200 according to this embodiment includes pressure contact members 210 and 220 that are in pressure contact with the first surface A and the second surface B, respectively, in addition to the configuration of the sound insulation structure 1 of the first embodiment. Have The pressure contact members 210 and 220 are both provided outside the films 10 and 11. Note that both of the pressure contact members 210 and 220 shown in FIG. 9 are in a non-pressure contact state. Then, both the pressure contact members 210 and 220 can move in the left-right direction in FIG. 9 and are pressed against the first surface A and the second surface B, respectively.

  Also in this embodiment, the sound insulation structure 200 can be switched between a sound insulation state and a non-sound insulation state by adjusting the pressure in the internal space 25 as in the first embodiment. That is, the sound insulation structure 200 can be brought into a non-sound insulation state by setting the pressure in the internal space 25 to a non-depressurized state. Moreover, the sound insulation structure 200 can be made into a sound insulation state by making the pressure of the internal space 25 into a pressure-reduced state.

  As shown in FIG. 9, the pressure contact member 210 has a plurality of convex portions 211 on the surface facing the first surface A. The plurality of convex portions 211 are formed at positions corresponding to the openings 23 of the frame 20 of the pressure contact member 210. For this reason, a groove 212 is formed between adjacent convex portions 211. In addition, the pressure contact member 220 has a plurality of convex portions 221 on the surface facing the second surface B. The plurality of convex portions 221 are formed at positions corresponding to the openings 24 of the frame 20 of the pressure contact member 220. For this reason, a groove 222 is formed between adjacent convex portions 221. That is, both the grooves 212 and 222 are formed in a lattice shape corresponding to the frame 20 shown in FIG. 2 when viewed from the front. For the pressure contact members 210 and 220, metal, resin, rubber, or the like having higher rigidity than the films 10 and 11 can be used.

  Moreover, in the sound insulation structure 200 of this embodiment, the height D of the convex portions 211 and 221 shown in FIG. 9 is made smaller than the projection amount C into the internal space 25 of the films 10 and 11 in the reduced pressure state. Furthermore, the curvature radii of the surfaces of the convex portions 211 and 221 are made larger than the curvature radii of the films 10 and 11 projecting into the internal space 25 in a reduced pressure state.

  And FIG. 10 is a figure which shows the sound insulation state of the sound insulation structure 200 of this form. As shown in FIG. 10, the sound insulation structure 200 in the sound insulation state is in a decompressed state, and has a shape protruding toward the internal space 25 toward the central portion of each opening 23, 24 of the films 10, 11.

  FIG. 10 shows the pressure contact state of the pressure contact members 210 and 220, and the pressure contact members 210 and 220 are in pressure contact with the first surface A and the second surface B, respectively. In addition, the convex portions 211 and 221 of the pressure contact members 210 and 220 protrude from the openings 23 and 24 toward the internal space 25, respectively. This is because the convex portions 211 and 221 are formed at positions corresponding to the openings 23 and 24, respectively.

  However, neither of the convex portions 211 and 221 is in contact with the films 10 and 11 at the positions of the openings 23 and 24 in the decompressed state, and a gap E is formed between them as shown in FIG. Yes. This is because the height D of the convex portions 211 and 221 is smaller than the protruding amount C of the films 10 and 11 in the decompressed state into the internal space 25 as described above with reference to FIG. Furthermore, the curvature radius of the surface of the convex portions 211 and 221 is larger than the curvature radius of the sound-insulated films 10 and 11.

  Therefore, the transmission loss of the sound insulation structure 200 of the present embodiment when the pressure contact members 210 and 220 are in the non-pressure contact state and in the non-decompression state is that of the sound insulation structure 1 of the first form in the non-decompression state. It is almost the same as transmission loss. In addition, the transmission loss of the sound insulation structure 200 according to the present embodiment when the pressure contact members 210 and 220 are in the reduced pressure state regardless of the pressure contact state or the non-pressure contact state is the first mode when the pressure contact member 210 or 220 is in the reduced pressure state. The transmission loss of the sound insulation structure 1 is almost the same.

  In the sound insulation structure 200, the pressure contact members 210 and 220 are brought into the pressure contact state even when the reduced pressure state cannot be maintained due to, for example, a failure of the exhaust pump 30 or a part of the films 10 and 11 being damaged. By doing so, it is possible to prevent a reduction in transmission loss from the time of the reduced pressure state. This is because the sound insulation structure 200 of the present embodiment can apply tension to the films 10 and 11 by the convex portions 211 and 221 by bringing the pressure contact members 210 and 220 into the pressure contact state even in a non-depressurized state. .

  Further, in the sound insulation structure 200 of this embodiment, the convex portions 211 and 221 are tensioned by making the curvature radius of the surfaces of the convex portions 211 and 221 larger than the curvature radius of the sound insulating films 10 and 11. The stress concentration on the films 10 and 11 is reduced. That is, the convex portions 211 and 221 have no sharp portions, and the films 10 and 11 are not pressed against the sharp portions. That is, even when tension is applied by the convex portions 211 and 221, the lifetime of the films 10 and 11 is long.

  The pressure contact members 210 and 220 may always be in a pressure contact state. That is, the pressure contact members 210 and 220 may be fixed in a pressure contact state. Moreover, the press contact members 210 and 220 should just have the convex parts 211 and 221 at the time of press contact. For example, when the pressure contact members 210 and 220 are made of a material having elasticity, the pressure contact members 210 and 220 may have a flat plate shape without the convex portions 211 and 221 in a non-pressure contact state. In this case, in the pressure contact state, the portions corresponding to the openings 23 and 24 of the pressure contact members 210 and 220 pressed against the frame 20 protrude due to the pressure contact force, thereby forming the convex portions 211 and 221. .

  As described above in detail, the sound insulation structure 200 includes the pressure contact members 210 and 220 that are in pressure contact with the first surface A and the second surface B, respectively, in addition to the configuration of the first embodiment. The pressure contact members 210 and 220 have convex portions 211 and 221 on the surfaces facing the first surface A and the second surface B, respectively, and tension is applied to the films 10 and 11 by the convex portions 211 and 221. Can do. That is, in this embodiment, it is possible to apply tension to the films 10 and 11 regardless of the pressure in the internal space 25. Therefore, the sound insulation structure 200 of this embodiment is lightweight and thin, and even when the reduced pressure state cannot be maintained, the press contact members 210 and 220 can prevent a decrease in transmission loss.

  Note that this embodiment is merely an example, and does not limit the present invention. Therefore, the present invention can naturally be improved and modified in various ways without departing from the gist thereof. For example, in the above embodiment, a configuration in which only the outer edge portions of the films 10 and 11 are joined to the surfaces 21 and 22 of the frame 20, respectively, has been described. However, the films 10 and 11 may be bonded around the openings 23 and 24 of the surfaces 21 and 22, for example. Alternatively, the film may be a bag that covers the frame 20. In this case, the bag-shaped film and the frame 20 may not be joined.

  In addition, for example, when it is used in a sound-insulated state at all times, it is manufactured by being sealed in a pressure-reduced state in which the pressure of the internal space 25 is set to a set pressure, and the exhaust pump 30, the pressure detector 31, the intake valve 32, The part 33 and the like may be omitted.

DESCRIPTION OF SYMBOLS 1,100,200 ... Sound insulation structure 10, 11, 110, 111 ... Film 20, 150 ... Frame 23, 24, 153, 154 ... Opening 25, 155 ... Internal space A ... 1st surface B ... 2nd surface

Claims (13)

A first surface and a second surface opposite to the first surface, blocking transmission of incident sound to one of the first surface and the second surface to the other surface; Sound insulation structure
A first surface portion located on the first surface side and a second surface portion located on the second surface side, wherein a hollow internal space is formed therein, and the first surface portion and the first surface portion A frame in which a plurality of openings connected to the internal space are formed in any of the two surface portions;
A flexible film that covers all the openings of the first surface portion and the second surface portion and partitions the internal space from an external space;
The internal space is depressurized to a pressure lower than atmospheric pressure, so that a portion on the opening of the film enters a curved shape toward the internal space and takes a depressurized state in which tension is applied to the film. A sound insulation structure characterized by being. The sound insulation structure according to claim 1,
An exhaust section for performing an exhaust operation for exhausting the air in the internal space to the outside;
A ventilation part that takes a ventilation state that allows air flow between the outside and the internal space and a non-ventilation state that does not allow the air flow;
A sound insulation structure characterized by being able to take the decompressed state and a non-depressurized state in which decompression of the internal space is released. The sound insulation structure according to claim 1,
A sound insulation structure that is maintained in the reduced pressure state. In the sound insulation structure in any one of Claims 1-3,
The frame is
The first surface portion and the second surface portion are configured as separate parts,
A sound insulation structure having a connection member disposed between the first surface portion and the second surface portion and connecting the first surface portion and the second surface portion with a space therebetween. The sound insulation structure according to claim 4,
The sound insulation structure according to claim 1, wherein the first surface portion and the second surface portion have different natural frequencies. In the sound insulation structure in any one of Claims 1-5,
The film is in a bag shape that accommodates the entire frame;
A sound insulation structure, wherein the film and the frame are not joined. In the sound insulation structure in any one of Claims 1-5,
As the film,
A first film covering only a part of the opening of the frame;
A second film covering an opening not covered by the first film;
Each of the first film and the second film is joined to the frame at an annular portion including all openings covered by the first film, and is not joined to the frame inside the annular portion. A sound insulation structure characterized by being. The sound insulation structure according to any one of claims 1 to 7,
A first outer member and a second outer member provided outside the film, respectively, with respect to the first surface portion and the second surface portion;
The first outer member and the second outer member are both
Having a convex portion at a position corresponding to the opening in the surface facing the frame;
The position between the convex part and the convex part is the groove part,
A sound insulation structure characterized in that it takes at least the pressure contact state between a pressure contact state pressed against the frame so that the convex portion enters the opening and a non-pressure contact state where pressure contact is released. body. The sound insulation structure according to claim 8,
The entry height from the opening of the convex portion in the pressure contact state to the internal space is:
The sound insulation structure according to claim 1, wherein a height of a portion of the film on the opening in the decompressed state is lower than an entrance height from the opening to the internal space. The sound insulation structure according to claim 8 or 9,
The radius of curvature of the surface of the convex portion when in the pressure contact state is
A sound insulation structure having a radius of curvature larger than a radius of curvature of the film on the opening in the reduced pressure state. The sound insulation structure according to any one of claims 1 to 10,
The sound insulation structure according to claim 1, wherein the frame is made of a material having viscoelasticity. The sound insulation structure according to any one of claims 1 to 11,
The sound insulation structure according to claim 1, wherein the opening has a chamfered edge portion. The sound insulation structure according to any one of claims 1 to 12,
A sound insulation structure, wherein at least the film of the film and the frame is transparent or translucent.

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