JP2001151107A - Soundproof construction of railway rolling stock - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a soundproof construction of a railway rolling stock exhibiting an excellent soundproofing property and simply manufacturable. SOLUTION: A pair of substrate plates 11 and 12 are placed in such a way to face to each other with a predetermined distance. A plural hollow portions 15 are provided between the pair of substrate plates 11 and 12 along a longitudinal direction so as to connect the pair of substrate plates 11 and 12 integrally, and an opening portion 14 is formed at both ends thereof. A hollow construction member 1 consists of an intermediate plate 13... Plural elastic small pieces 2... are filled in the hollow portions 15... through the opening potion 14 of the hollow construction member 1. A plug 3 is provided at the opening portion 14 to plug up thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a soundproof structure for a railway vehicle which is suitably used for a ceiling, a side wall, a floor, etc. forming a passenger compartment space of a railway vehicle.

[0002]

2. Description of the Related Art Conventionally, steel plates and the like have been used for ceilings, side walls, floors, and the like that form passenger compartments of railway vehicles. In order to cope with the demand, a plate material having a hollow structure has been adopted. As such a plate member having a hollow structure, a pair of substrates disposed opposite each other at a distance and an intermediate member disposed between the two substrates so as to integrally connect the two substrates and forming a hollow portion together with the two substrates. Plates are widely used. In addition, such a hollow structural member,
For example, it is manufactured from a metal material such as an aluminum alloy or steel by extrusion molding, welding, brazing, or the like.

[0003] In order to improve the vibration-damping and sound-insulating properties of such hollow structural members, there are various sound-insulating structures in which a sound-insulating material such as a foamed rubber elastic body or a vibration damping material is disposed in the hollow portion. Are known. For example, JP-A-7-172305
Japanese Patent Application Laid-Open Publication No. H11-157, discloses a soundproof structure in which a hollow portion of a hollow structural member is filled with a foamed rubber elastic body having an open cell structure composition and compressed and deformed to a predetermined state. This soundproof structure can achieve excellent vibration damping effects without a significant increase in weight. Also, JP-A-9-48
No. 079 discloses a soundproof structure in which a vibration-damping resin is provided on the inner wall surface of a hollow portion of a hollow structural member to improve the vibration-damping characteristics.

The soundproof structures disclosed in these publications are used as components such as ceilings, side walls, and floors that form the passenger compartment of a railway vehicle, thereby shutting off noise and vibration from the outside, and making the passenger compartment quiet. Can be enhanced.

[0005]

By the way, railway vehicles are usually formed to have a length exceeding 10 m, and some railway vehicles are formed as long as 20 m or more like Shinkansen vehicles. Therefore, the soundproof structure used for the ceiling, side walls, floor, etc. of those vehicles will be of a considerably long length corresponding to the length of the vehicle, and the foam rubber elasticity arranged in the hollow part will be used. Since the soundproofing material such as the body and the vibration damping material is also disposed over substantially the entire area in the longitudinal direction, a considerably long material is required.

However, since it is very difficult to insert such a long soundproofing material in contact with the inner surface of the hollow portion or to uniformly arrange it in the longitudinal direction,
The above-mentioned conventional soundproofing structure has a drawback that the production becomes very complicated. Further, since a more comfortable cabin space is required, further improvement of the soundproof performance of the soundproof structure is desired.

[0007] The present invention has been devised in view of the above situation, and it is an object of the present invention to provide a soundproof structure for a railway vehicle which can ensure excellent soundproof performance and can be easily manufactured. Is what you do.

[0008]

According to a first aspect of the present invention, there is provided a semiconductor device comprising: a pair of substrates which are opposed to each other with a distance therebetween; A hollow structural member comprising a plurality of intermediate plates connected to each other and extending in the longitudinal direction together with the substrates to form a plurality of hollow portions having an opening at at least one end, and the hollow portion is filled into the hollow portion from the opening of the hollow structural member. Means of being constituted by a large number of elastic pieces and a plug member for sealing the opening is adopted.

In the soundproof structure for a railway vehicle according to the present invention, when vibration from a sound source is applied, the hollow structural member is vibrated and starts to vibrate. At this time, when the respective plane portions of the substrate and the intermediate plate that define the hollow portion vibrate, a large number of elastic small pieces filled in the hollow portion jump up and come into contact with other elastic small pieces, the substrate, or the intermediate plate. Contact), and a damping property is exerted by energy loss due to sliding friction and collision. Thereby, the vibration of the substrate and the intermediate plate is effectively suppressed, and the vibration of the hollow structural member is effectively suppressed.

[0010] Further, as the substrate and the intermediate plate vibrate as described above, the sound incident into the hollow portion defined by the substrate and the intermediate plate is generated by the elastic small pieces filled in the hollow portion. When passing through, sound energy is absorbed by being converted into thermal energy. In addition, since a void is formed between a large number of elastic pieces filled in the hollow portion, the sound passing through each elastic piece and emitted to the gap enters the nearby elastic piece. Then, the sound is further absorbed, or the sound is further absorbed by being diffusely reflected on the surface of the elastic piece and entering another elastic piece.

As described above, since a good sound absorbing structure is formed by forming a gap between a number of elastic pieces filled in the hollow portion, the elastic piece itself has a sound absorbing function. Even if a relatively small rubber tip or the like is used, good sound absorbing performance can be ensured.

Since such an elastic piece is smaller than the opening of the hollow structural member, the operation of filling the elastic piece into the hollow portion can be easily performed even on a long hollow structural member. Can be manufactured, and the production becomes very simple.

Therefore, the soundproofing structure for a railway vehicle according to the present invention can be easily manufactured because excellent soundproofing performance can be ensured and the work of filling the elastic piece into the hollow portion can be easily performed. be able to.

It is to be noted that the hollow structural member of the present invention comprises a pair of substrates opposed to each other at a distance, and is disposed between the two substrates to integrally connect the two substrates and extend in the longitudinal direction together with the two substrates. A general one including an intermediate plate forming a plurality of hollow portions having an opening at one end can be employed. In particular, a so-called truss-type hollow structural member having a plurality of hollow portions having a triangular cross section in which the intermediate plate is bent and arranged in a zigzag shape between the two substrates is preferable because it has an advantageous structure from the viewpoint of high strength It is. As the hollow structural member, a member manufactured by extrusion, welding, brazing, or the like from a metal material such as an aluminum alloy or steel can be employed.

The elastic piece according to the present invention has a size smaller than at least the opening of the hollow structural member. As the elastic small piece, for example, a piece obtained by breaking or crushing a block-shaped elastic body to form a small piece can be adopted, and for example, an arbitrary shape such as a granular shape or a spindle shape can be adopted. Can be. As the elastic small pieces, for example, small pieces made of urethane foam, foamed rubber, rubber, or the like can be used. In particular, urethane foam is suitable because of its high sound absorbing performance. The elastic small piece is filled in the hollow portion of the hollow structural member in a state where a large number of the pieces move freely. That is,
A random gap is formed between the elastic pieces filled in the hollow portion, and this gap also forms a sound absorbing structure for absorbing the sound incident into the hollow portion. The porosity in this hollow part is 5
By setting the value to about 70%, the vibration at the target frequency can be satisfactorily reduced.

The elastic piece according to the present invention does not necessarily need to be filled in all the hollow portions of the hollow structural member, but can be filled only in appropriately selected hollow portions. For example, the elastic small piece can be filled only in a hollow portion formed by one of the substrates and the intermediate plate disposed on the indoor side of the railway vehicle. Further, the size of the elastic foam filled in each hollow portion may be variously changed, and the porosity in each hollow portion may be appropriately changed.

The plug member according to the present invention is attached to an opening provided at at least one end of the hollow portion of the hollow structural member, seals the opening, and is provided outside the elastic small piece filled in the hollow portion. To prevent outflow. As the plug member, an arbitrary member such as a member formed of the same metal material as the hollow structural member or a member formed of the same elastic material as the elastic piece can be adopted. In particular, the use of a material having a good sound absorbing function is preferable because the soundproofing performance of the entire soundproofing structure is improved.

The invention described in claim 2 is the first invention.
In the above invention, the porosity in the hollow portion is 5-7.
The means of 0% is adopted.

According to this means, a favorable vibration reduction effect can be obtained by appropriately setting the porosity in accordance with the frequency of the vibration to be reduced. If the porosity is set in the above range, the harmful vibration usually occurs.
Vibration of 00 to 5000 Hz can be reduced favorably.

According to a third aspect of the present invention, in the first or second aspect of the present invention, an elongated foamed elastic body having a sectional shape smaller than a sectional shape of the opening is provided in the hollow portion. Means of being inserted and arranged from the opening is adopted.

According to this means, excellent soundproofing performance can be ensured by disposing a foamed elastic body functioning as a sound absorbing material together with a large number of elastic pieces in a part of the hollow portion of the hollow structural member. In addition, since the foamed elastic body has a cross-sectional shape smaller than the cross-sectional shape of the opening, the work of inserting the foamed elastic body into the hollow portion can be easily performed, and the simplicity of manufacturing can be maintained.

As the foamed elastic body, one having simultaneous cells is preferably employed, and for example, urethane foam or foamed rubber can be employed. In particular, urethane foam having excellent sound absorption characteristics and vibration damping characteristics can be suitably used.

[0023]

Embodiments of the present invention will be described below with reference to the drawings.

[Embodiment 1] FIG. 1 is a cross-sectional view taken along a longitudinal direction of a soundproofing structure for a railway vehicle according to the present embodiment, and is a cross-sectional view taken along line II of FIG. 2 is FIG.
2 is a sectional view taken along line II-II of FIG.

As shown in FIGS. 1 and 2, the railway vehicle soundproofing structure of this embodiment comprises a pair of substrates 11, 12 and an intermediate plate 13, has a triangular cross section, and has openings 14 at both ends. , A hollow structural member 1 having a plurality of hollow portions 15,.
, And a large number of elastic pieces 2,... Filled in the hollow portions 15,..., And a plug member 3 (only one is shown in FIG. It is composed of

The hollow structural member 1 includes a pair of substrates 11 and 12 which are opposed to each other in a substantially parallel manner with a distance therebetween.
The two substrates 11, 12 are bent and arranged in a zigzag shape between
And an intermediate plate 13 that integrally connects them. Intermediate plate 13
Are extended in a zigzag manner while bending at a substantially right angle from one end side to the other end side in the width direction of the hollow structural member 1, and every other bent corner portion has the substrate 11 on each side,
12.

Thus, between the substrates 11 and 12,
A plurality of hollow portions 15 having a triangular cross section and extending in the longitudinal direction, ...
Are regularly arranged in the width direction, and openings 13 having the same triangular cross-section as the hollow portions 15 are formed at both ends of each hollow portion 15,. That is, each of the hollow portions 15,... Having a triangular cross section, has one of the substrates 11, 12 defining one of the three planes, and an intermediate portion bent into a U-shape to define the other two planes. It is formed by the plate 13. This hollow structural member 1 is integrally formed of an extruded material made of an aluminum alloy.

The elastic pieces 2,... Are urethane foam chips having simultaneous cells, and have a size of about 5 to 10 mm. Each of the elastic pieces 2,... Is a hollow portion 1 formed on one substrate 12 side of the hollow structural member 1.
5,... Are filled from the opening 14 and arranged. That is, the elastic small pieces 2,...
A plug member 3 described below is attached to only one opening 14 of
When the hollow structural member 1 is set in an inclined manner so that the sealed opening 14 is directed downward, the hollow structural member 1 is poured into the respective hollow portions 15,. I have. In addition, this elastic piece 2, ...
Each of the hollow portions 15,... Is tuned so as to have a porosity of 40%, and is filled with a predetermined amount.

The plug member 3 is formed in a triangular prism shape by urethane foam. The plug member 3 is attached by press-fitting into the opening 14 of the hollow structural member 1 and seals the opening 14. The one plug member 3 is attached before the elastic small pieces 2,... Are filled in the hollow portions 15,.
5,... Are attached after the elastic small pieces 2,.

A plurality of the soundproofing structures for a railway vehicle according to the present embodiment configured as described above are welded, bolted, or the like directly at the ends in the width direction or through appropriate connecting members. Are used for ceilings, side walls, floors, etc. of railway vehicles. In the case of the soundproof structure of the present embodiment, one of the substrates 12 defining the hollow portions 15,... Filled with the elastic small pieces 2,. Can be

The noise generated outside the vehicle is shielded by colliding with the soundproof structure and being reflected, but the collision of the noise causes vibration to be applied to the hollow structural member 1.
Thereby, the substrate 11, which defines each hollow portion 15,.
When the plane portions of the intermediate plate 12 and the intermediate plate 13 vibrate, the hollow portion 1
.., A large number of elastic pieces 2,... Filled therein jump and come into contact with (contact with) other elastic pieces 2,..., The substrate 12 or the intermediate plate 13, causing sliding friction and collision. Attenuation is exhibited by the energy loss due to this. Thereby, the vibration of the substrate 12 and the intermediate plate 13 is effectively suppressed, and the vibration of the hollow structural member 1 is effectively suppressed.

Also, as described above, the substrate 12 and the intermediate plate 1
As the substrate 3 vibrates, its substrate 12 and intermediate plate 13
The sound incident into the hollow part 15,... Defined by
When passing through the elastic small pieces 2, ... filled in the hollow portions 15, ..., sound energy is converted into heat energy to absorb sound. In addition, hollow part 15,
... Between the many elastic small pieces 2,.
Since the voids are formed, each elastic piece 2,.
Is emitted to the gap portion after passing through the elastic piece 2,..., And is further absorbed by the adjacent elastic piece 2,..., Or diffusely reflected on the surface of the elastic piece 2,. 2,
The sound is further absorbed by being incident on.

As described above, the soundproof structure for a railway vehicle according to the present embodiment has a structure in which a large number of elastic pieces 2,... Have a predetermined porosity in the hollow portions 15,. Since it is tuned and filled, excellent soundproof performance can be ensured.

Also, a large number of small elastic pieces 2 filled in the hollow portion 15,... From the opening 14 of the hollow structural member 1,.
... is smaller than the opening 14 of the hollow structural member 1,
.. Can be easily filled into the hollow portions 15,... Of the elastic small pieces 2,. Therefore, the railway vehicle soundproofing structure of the present embodiment,
Very easy to manufacture.

[Embodiment 2] FIG. 3 is a sectional view taken along the longitudinal direction of the soundproof structure for a railway vehicle according to the present embodiment, and is a sectional view taken along line III-III in FIG. 4 is a cross section taken along line IV-IV in FIG.

As shown in FIGS. 3 and 4, the soundproof structure for a railway vehicle according to the present embodiment is composed of a pair of substrates 11a, 12a and an intermediate plate 13a, has a triangular cross section, and has openings 1 at both ends.
4a (only one is shown in FIG. 3), a hollow structural member 1a having a plurality of hollow portions 15a,... And a hollow structural member 1a inserted and disposed in the hollow portions 15a,. A long foamed elastic body 4a, a large number of elastic small pieces 2a filled in hollow portions 15a of the hollow structural member 1a,...
, And a plug member 3a (only one is shown in FIG. 3) for sealing both openings 14a. In addition, the hollow structural member 1a and the plug member 3 of this embodiment
Since a is the same as that of the first embodiment, detailed description is omitted.

The foamed elastic member 4a is made of urethane foam having simultaneous cells, and has an opening 14a and a hollow portion 15a.
a, formed into a belt shape having a rectangular cross-sectional shape smaller than the cross-sectional shape of. The foamed elastic body 4a is arranged by being inserted into one of the hollow portions 15a,... Formed on the one substrate 12a side of the hollow structural member 1a through one opening 14a, and one surface of a wide side thereof. Are in contact with the central portion in the width direction of the substrate 12a, and the corners of the other surface on the wide side are in contact with the substantially central portion in the width direction of the intermediate plate 13a.

The elastic pieces 2a,... Are urethane foam chips having simultaneous cells, and have a size of about 5 to 10 mm. This elastic piece 2a,... Is provided with one opening 1 in the hollow portion 15a, in which the foamed elastic body 4a is inserted and arranged first, in the same manner as in the first embodiment.
Filled by pouring from 4a. The elastic small pieces 2a,... Are tuned so that the porosity of the portions other than the foamed elastic body 4a in each hollow portion 15a,. .

The soundproof structure for a railway vehicle of the present embodiment configured as described above is similar to that of the first embodiment.
The plurality of sheets are connected to each other to be used for ceilings, side walls, floors and the like of railway vehicles. In this case as well, the substrate 12a on the side where the foamed elastic body 4a and the elastic small pieces 2a,... Are arranged is mounted inside the vehicle compartment.

Also, in the case of the soundproofing structure for a railway vehicle of the present embodiment, the hollow portions 15a of the hollow structural member 1a,.
Since the foamed elastic body 4a and the elastic small pieces 2a,... Are filled therein, excellent soundproofing performance can be ensured as in the case of the first embodiment.

Further, the foamed elastic body 4a and the elastic pieces 2a,... Disposed in the hollow portions 15a,... Are inserted or filled into the hollow portions 15a,. The work of inserting and filling the long hollow structural member 1a can be easily performed. Therefore, as in the case of the first embodiment, the manufacturing becomes very simple.

Accordingly, the soundproof structure for a railway vehicle according to the present embodiment has the same functions and effects as those of the first embodiment, such as securing excellent soundproof performance and being easily manufactured. .

[Embodiment 3] FIG. 5 is a sectional view taken along the longitudinal direction of the soundproofing structure for a railway vehicle according to the present embodiment, and is a sectional view taken along line VV in FIG. 6 is FIG.
6 is a sectional view taken along line VI-VI of FIG.

As shown in FIGS. 5 and 6, the soundproofing structure for a railway vehicle according to the present embodiment includes a pair of substrates 11b and 12b and an intermediate plate 13b, and has a triangular cross section and openings 1 at both ends.
4b (only one is shown in FIG. 5), a hollow structural member 1b having a plurality of hollow portions 15b,... And a hollow structural member 1b inserted and disposed in the hollow portions 15b,. A long foamed elastic body 4b, a large number of elastic small pieces 2b filled in hollow portions 15b of the hollow structural member 1b,...
, And a plug member 3b (only one is shown in FIG. 5) for sealing both openings 14b.

The soundproof structure for a railway vehicle of this embodiment is different from that of the second embodiment in that the shape of the foamed elastic body 4b and the material of the elastic small pieces 2b are different. And a detailed description of common members and the like will be omitted.

The foamed elastic body 4b is made of urethane foam having simultaneous cells, and has an opening 14b and a hollow portion 15b.
It is a long one having an elliptical cross section slightly smaller than the ellipse inscribed in the triangle having the cross section of b,.... This foamed elastic body 4b is provided with one opening 14b in each hollow portion 15b,... Formed on the one substrate 12b side of the hollow structural member 4b in the same manner as in the second embodiment.
It is arranged by inserting from. The foamed elastic body 4b is arranged so as to be in contact with the central portion in the width direction of the substrate 12b and the central portion in the width direction of the intermediate plate 13b, respectively.

The elastic pieces 2b are rubber chips having a size of about 3 to 5 mm. This elastic piece 2b, ...
Are filled in each hollow portion 15b, in which the foamed elastic body 4b is arranged, by pouring from one of the openings 14b in the same manner as in the case of the second embodiment. In addition,
Each of the elastic small pieces 2b,... Is tuned so as to have a porosity of 40% at a portion other than the foamed elastic body 4b in each hollow portion 15b,.

The railway vehicle soundproof structure of the present embodiment configured as described above has a hollow portion 15 of the hollow structural member 1b.
b,..., within which the foamed elastic body 4b and the elastic piece 2b,.
Are filled and arranged, as in the case of the second embodiment, excellent soundproofing performance can be ensured.

Particularly, in this embodiment, the elastic small pieces 2b,
A rubber chip having a relatively small sound absorbing function is used as..., But a void is formed between a large number of elastic pieces 2b filled in the hollow portions 15b. As a result, a good sound absorbing structure is formed, so that good sound absorbing performance is secured.

The foamed elastic body 4b and the small elastic pieces 2b arranged in the hollow portions 15b are inserted or filled into the hollow portions 15b from the opening 14b. The insertion work and the filling work can be easily performed on the long hollow structural member 1b. Therefore, the soundproof structure for a railway vehicle according to the present embodiment can be manufactured very easily, as in the case of the second embodiment.

[Test] In this test, an elastic piece was
The following four types of rubber chips with different shapes and sizes are prepared, and when each rubber chip is filled into the hollow portion of the hollow structural member, the porosity in the hollow portion is variously changed to prepare test samples. This is to measure and compare the normal incidence sound absorption coefficient of the sample. The first kind of rubber chip is
It has a spindle shape with a diameter of 1 to 2 mm and a length of 5 to 20 mm. The second type of rubber chip is of a mesh type having a particle size of 2 to 5 mm. Third
Rubber chips are of the rough type formed with a particle size of 5 to 10 mm. The fourth type of rubber chip is of a cloth-containing type having a particle size of 10 to 25 mm.

The first type of rubber chips having a porosity of 30% and 40% were prepared. As the second type of rubber chips, those having porosity of 20%, 30% and 40% were prepared. The third type of rubber chip has a porosity of 20%, 30% and 40%.
% Was prepared. A fourth type of rubber chip having a porosity of 40% was prepared. Then, for each test sample, 50 to 5000 by a predetermined method under the same conditions.
The vertical incidence sound absorption coefficient in the frequency range of Hz was measured, and the measurement results of the rubber chips of the first to fourth classes are shown in FIG.
10 to FIG.

As is clear from FIGS. 7 to 10, the first
It can be seen that the normal incidence sound absorption coefficient becomes extremely good in a certain frequency range in any of the test samples of the rubber chips of Classes 4 to 4. This is because a large number of rubber chips are filled so as to form a predetermined gap in the hollow portion, and the gap forms a sound absorbing structure that absorbs sound that has entered the hollow portion. Therefore, even if a rubber chip having a relatively small sound absorbing function is used, a good sound absorbing performance can be obtained if a large number of rubber chips are filled so as to form a predetermined gap in the hollow portion.

As is clear from FIGS. 7 to 9,
It can be seen that when the porosity in the hollow portion is different, the frequency at which the normal incidence sound absorption coefficient has a peak is different, and the peak level of the normal incidence sound absorption coefficient is also different. Therefore, it is possible to appropriately set the porosity in the hollow portion in accordance with the frequency of the vibration for which the reduction is to be performed, whereby a favorable vibration reduction effect can be obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view taken along a longitudinal direction of a railway vehicle soundproofing structure according to Embodiment 1 of the present invention.
FIG. 2 is a sectional view taken along line I of FIG.

FIG. 2 is a sectional view taken along line II-II in FIG.

FIG. 3 is a cross-sectional view taken along a longitudinal direction of the railway vehicle soundproof structure according to Embodiment 2 of the present invention, and is a sectional view taken along line II of FIG.
FIG. 3 is a sectional view taken along line I-III.

FIG. 4 is a cross-sectional view taken along line IV-IV of FIG. 3;

5 is a cross-sectional view taken along a longitudinal direction of a railway vehicle soundproofing structure according to Embodiment 3 of the present invention, and is a sectional view taken along line V in FIG.
FIG. 5 is a cross-sectional view taken along line V.

FIG. 6 is a sectional view taken along line VI-VI of FIG. 5;

FIG. 7 is a graph showing a measurement result of a normal incidence sound absorption coefficient of a first type rubber chip in a test.

FIG. 8 is a graph showing a measurement result of a normal incidence sound absorption coefficient of a second type of rubber chip in a test.

FIG. 9 is a graph showing a measurement result of a normal incidence sound absorption coefficient of a third type of rubber chip in a test.

FIG. 10 is a graph showing a measurement result of a normal incidence sound absorption coefficient of a fourth type of rubber chip in a test.

[Explanation of symbols]

1, 1a, 1b ... hollow structural members 11, 12, 11a, 12a, 11b, 12b ... substrates 13, 13a, 13b ... intermediate plates 15, 15a, 1
5b hollow part 2, 2a, 2b elastic piece 3, 3a, 3b plug member 4a, 4b foam elastic body

Claims (3)

[Claims] 1. A pair of substrates disposed opposite each other at a distance and disposed between the substrates, integrally connecting the substrates, extending in a longitudinal direction together with the substrates, and having an opening at at least one end. A hollow structural member including an intermediate plate forming a plurality of hollow portions; a large number of elastic pieces filled into the hollow portion from the opening of the hollow structural member; and a plug member for sealing the opening. A soundproof structure for a railway vehicle, comprising: 2. The soundproofing structure for a railway vehicle according to claim 1, wherein the porosity in the hollow portion is 5 to 70%. 3. An elongated foam elastic body having a cross-sectional shape smaller than the cross-sectional shape of the opening is disposed in the hollow portion so as to be inserted from the opening. 2. The soundproof structure for a railway vehicle according to 1.