JP6932588B2 - Luggage racks and railcars - Google Patents

Description

The present invention relates to a luggage rack and a railroad vehicle to which the luggage rack is applied.

In the field of railway vehicles, measures against noise generated during traveling are always required from the viewpoint of improving passenger comfort. As a technique to which a structure for noise control is applied inside a railway vehicle, for example, there is a railway vehicle described in Patent Document 1. This conventional railroad vehicle is provided with a lid that can be opened and closed with respect to the luggage rack. The lid has a structure in which a sound absorbing material such as glass wool is sandwiched between a pair of perforated plates to absorb sound energy.

Japanese Unexamined Patent Publication No. 2010-100278

In the conventional railway vehicle described above, the noise level is lowered by absorbing sound energy, but it does not have the effect of absorbing sound in a specific frequency band. In particular, in a railroad vehicle traveling at high speed, sound in a low frequency band near 250 Hz or 100 Hz, for example, may be a problem, and a technique capable of selectively absorbing sound in a desired frequency band is required. Further, when noise countermeasures are taken inside a railway vehicle, it is preferable to avoid changing the existing configuration or adding the configuration as much as possible.

The present invention has been made to solve the above problems, and applies a luggage rack capable of selectively absorbing sound in a desired frequency band while avoiding changes in the internal configuration of a railway vehicle, and such a luggage rack. The purpose is to provide railcars.

The luggage rack according to one aspect of the present invention includes a main body portion in which a loading surface on which luggage is placed is provided along the longitudinal direction, and the main body portion includes a hollow portion extending in the longitudinal direction and a hollow portion. It has an air column resonance hole that communicates with the outside.

In this luggage rack, a hollow portion extending in the longitudinal direction of the main body portion communicates with the outside by an air column resonance hole portion. With this configuration, a standing wave is generated in the hollow portion, and at a resonance frequency determined by the length of the hollow portion from the position of the air column resonance hole, sound absorption is performed by the viscous resistance of air around the open end of the air column resonance hole. The effect is played. Therefore, in this luggage rack, sound in a desired frequency band can be selectively absorbed by changing the length of the main body and the position of the air column resonance hole. Further, since this sound absorbing effect is realized by forming the hollow portion and the air column resonance hole portion in the luggage rack, it is possible to suppress the influence on the internal configuration of the railway vehicle.

Further, both one end surface and the other end surface in the longitudinal direction of the main body portion are closed ends provided with a wall portion so that the hollow portion is not exposed, and the air column resonance hole portion is a mounting surface on the main body portion. It may be provided on the surface opposite to the above. In this case, the frequency band for sound absorption can be easily adjusted depending on the position of the air column resonance hole portion. Further, since the air column resonance hole portion is provided on the surface opposite to the mounting surface, the air column resonance hole portion faces downward when applied to a railway vehicle. Therefore, the sound absorption effect can be improved.

Further, the main body portion may have a plurality of hollow portions, and the air column resonance hole portion may be provided for the plurality of hollow portions so that the positions in the main body portion in the longitudinal direction are different from each other. In this case, sound in a plurality of frequency bands can be selectively absorbed according to the position of the air column resonance hole portion.

Further, the main body portion may have a plurality of hollow portions, and the air column resonance hole portion may be composed of notches that expose the plurality of hollow portions. In this case, sound in a plurality of frequency bands can be selectively absorbed according to the position of the notch.

Further, one end surface in the longitudinal direction of the main body is an open end provided with an air column resonance hole so that the hollow portion is exposed, and the other end surface in the longitudinal direction of the main body is not exposed. It is a closed end with a wall. In this case, the frequency band for sound absorption can be easily adjusted by the length of the main body.

Further, both one end surface and the other end surface in the longitudinal direction of the main body portion may be open ends provided with air column resonance holes so that the hollow portion is exposed. In this case, the frequency band for sound absorption can be easily adjusted by the length of the main body.

Further, a sound absorbing material may be arranged at at least one of the open end and the closed end of the air column resonance hole portion. In this case, the sound absorbing material can absorb sound in a wide frequency band. By arranging the sound absorbing material at at least one of the open end and the closed end of the air column resonance hole portion, the selectivity of the frequency band for sound absorption can be maintained.

Further, a sound absorbing material may be arranged at at least one of the open end and the closed end. In this case, the sound absorbing material can absorb sound in a wide frequency band. By arranging the sound absorbing material at at least one of the open end and the closed end, the selectivity of the frequency band for sound absorption can be maintained.

Further, a sound absorbing material may be arranged on at least one of the open ends on one side and the other side of the main body. In this case, the sound absorbing material can absorb sound in a wide frequency band. By arranging the sound absorbing material on at least one of the open ends on one side and the other side of the main body, the selectivity of the frequency band for sound absorption can be maintained.

Further, in the railroad vehicle according to one aspect of the present invention, the luggage rack is fixed to the inner upper part of the side structure.

In this railroad vehicle, the sound of a desired frequency band can be selectively absorbed by applying the luggage rack. Further, since the sound absorbing effect of the luggage rack is realized by forming the hollow portion and the air column resonance hole portion in the luggage rack, it is possible to suppress the influence on the internal configuration of the railway vehicle.

According to the present invention, it is possible to selectively absorb sound in a desired frequency band while avoiding changes in the internal configuration of a railway vehicle.

It is a schematic cross-sectional view which shows one Embodiment of a railroad vehicle. It is a perspective view which shows one Embodiment of a luggage rack. It is a top view of the luggage rack shown in FIG. It is a top view which shows the modification of the luggage rack. It is a top view which shows another modification of a luggage rack. It is a figure which shows the verification result of the sound absorption effect of a luggage rack. It is a figure which shows the verification result of the sound absorption effect of a luggage rack. It is a figure which shows the verification result of the sound absorption effect of a luggage rack. It is a top view which shows the further modification of the luggage rack.

Hereinafter, preferred embodiments of the luggage rack and railroad vehicle according to one aspect of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic cross-sectional view showing an embodiment of a railroad vehicle. As shown in the figure, the railroad vehicle 1 is composed of a floor structure 2, a side structure 3, a roof structure 4, a wife structure (not shown), and the like. In the side structure 3, windows 5 are arranged at regular intervals in the longitudinal direction of the railway vehicle 1. The internal space of the railroad vehicle 1 is a passenger compartment S, and for example, a seat 6 and a luggage rack 11 are provided.

The seats 6 are arranged on the left and right sides of the passenger compartment S with the aisle, for example, and are fixed to the floor structure 2 so that a plurality of passengers and the like can sit in the longitudinal direction of the railway vehicle 1. The luggage rack 11 is a shelf for passengers and the like to load luggage, and is provided above the seat 6 along the longitudinal direction of the railroad vehicle 1. The luggage rack 11 is fixed to the inner upper part of the side structure 3 so as to be substantially horizontal or inclined upward toward the center side of the passenger compartment S. Further, the luggage rack 11 does not have to match the length of the seat 6, and a plurality of luggage racks 11 may be arranged along the longitudinal direction of the railroad vehicle 1.

Next, the configuration of the luggage rack 11 will be described in more detail.

FIG. 2 is a perspective view showing an embodiment of a luggage rack. Further, FIG. 3 is a plan view of the luggage rack shown in FIG. As shown in FIGS. 2 and 3, the luggage rack 11 includes a hollow main body portion 12 in which a loading surface 12a on which luggage is placed is provided along the longitudinal direction. The main body 12 is made of an extruded mold material using a lightweight and easy-to-process material such as aluminum, and has a flat shape.

A plurality of truss-shaped ribs 13 are provided in the internal space of the main body 12. The rib 13 is formed integrally with the main body portion 12, for example, when the main body portion 12 is extruded. Due to these ribs 13, a plurality of hollow portions F having a triangular cross section extending in the longitudinal direction of the main body portion 12 are arranged in the internal space of the main body portion 12 in the width direction of the main body portion 12. In the present embodiment, the hollow portion F is a first hollow portion FA in which the bottom surface of the triangle faces the mounting surface 12a in the cross-sectional shape, and a surface in which the bottom surface of the triangle faces the mounting surface 12a in the cross-sectional shape. It includes two second hollow portions FB facing the side (hereinafter referred to as the opposite surface 12b).

Further, in the present embodiment, both the one end surface 12c and the other end surface 12d of the main body portion 12 in the longitudinal direction are closed ends provided with wall portions 14 so that the hollow portion F is not exposed. Further, an air column resonance hole portion H is provided on the opposite surface 12b of the main body portion 12. The air column resonance hole portion H is a hole (opening) that causes air column resonance by communicating the hollow portion F extending in the longitudinal direction of the main body portion 12 with the outside.

With this configuration, a standing wave is generated in the hollow portion F, and the air around the open end of the air column resonance hole H is at a resonance frequency determined by the length of the hollow portion F from the position of the air column resonance hole H. The sound absorption effect is produced by the viscous resistance of. When the one end surface 12c and the other end surface 12d of the main body 12 in the longitudinal direction are closed ends as in the present embodiment, the period of the standing wave generated between the air column resonance hole H and the closed end. The relational expression of L = 1/4λ (= 3/4λ, = 5 / 4λ ...) Between λ and the length (distance from the air column resonance hole H to the closed end) L of the hollow portion F. Holds. Further, between the resonance frequency and the period λ, the relational expression of f = v / λ holds when the speed of sound is v. Therefore, in the luggage rack 11, sound in a desired frequency band can be selectively absorbed by changing the length L of the main body 12 and the positions of the air column resonance hole H.

In this embodiment, two air column resonance holes H1 and H2 are provided on opposite surfaces 12b. As shown in FIG. 3, the air column resonance holes H1 and H2 have a circular cross section, and are provided so as to communicate with each of the two second hollow portions FB on the opposite surface 12b. Further, the air column resonance hole portions H1 and H2 are provided with respect to the two second hollow portions FB so that the positions in the longitudinal direction of the main body portion 12 are different from each other.

In the example of FIG. 3, in the air column resonance hole portion H1 provided for one of the second hollow portions FB, the distance L1 to the one end surface 12c, which is the closed end, is 500 mm, and up to the other end surface 12d, which is the closed end. The distance L2 is 3000 mm. Therefore, the frequencies of the sound absorbed by the air column resonance hole H1 are estimated to be about 170 Hz and about 28 Hz. Further, in the air column resonance hole portion H2 provided for the other second hollow portion FB, the distance L3 to the one end surface 12c which is the closed end is 1500 mm, and the distance L4 to the other end surface 12d which is the closed end is It is 2000 mm. Therefore, the frequencies of the sound absorbed by the air column resonance hole H2 are estimated to be about 57 Hz and about 43 Hz. However, the frequency of the sound absorbed by the air column resonance holes H1 and H2 may be slightly shifted by the end correction due to the hole shape.

Further, as shown in FIGS. 2 and 3, a sound absorbing material 15 may be arranged at the open ends of the air column resonance holes H1 and H2. The sound absorbing material 15 is arranged inside the holes in a range of about 10 mm to 20 mm from the open ends of the air column resonance holes H1 and H2. Further, the sound absorbing material 16 may be arranged on the entire inner surface of the wall portion 14 at the one end surface 12c and the other end surface 12d which are the closed ends. The sound absorbing material 16 is arranged in a range of about 10 mm to 20 mm from the inner surface of the wall portion 14. As the sound absorbing materials 15 and 16, for example, glass wool, open cell foamed resin, or the like can be used.

As described above, in the luggage rack 11, the hollow portion F extending in the longitudinal direction of the main body portion 12 communicates with the outside by the air column resonance hole portion H. With this configuration, a standing wave is generated in the hollow portion F, and the air around the open end of the air column resonance hole H is at a resonance frequency determined by the length of the hollow portion F from the position of the air column resonance hole H. The sound absorption effect is produced by the viscous resistance of. Therefore, in the luggage rack 11, the sound in a desired frequency band can be selectively absorbed by changing the length of the main body 12 and the position of the air column resonance hole H. Further, since this sound absorbing effect is realized by the formation of the hollow portion F and the air column resonance hole portion H in the luggage rack 11, it is possible to suppress the influence on the internal configuration of the railway vehicle 1.

Further, in the present embodiment, the one end surface 12c and the other end surface 12d of the main body portion 12 in the longitudinal direction are both closed ends provided with the wall portion 14 so that the hollow portion F is not exposed. The air column resonance hole portion H is provided on the opposite surface 12b of the main body portion 12. With such a configuration, the frequency band for sound absorption can be easily adjusted depending on the position of the air column resonance hole portion H. Since the frequency band for sound absorption is adjusted according to the position of the air column resonance hole portion H, the length of the main body portion 12 can be made relatively long. Therefore, it is possible to reduce the number of luggage racks 11 arranged in the longitudinal direction of the railroad vehicle 1. Further, since the air column resonance hole portion H is provided on the surface opposite to the mounting surface 12a, the air column resonance hole portion H faces downward when applied to the railway vehicle 1. Therefore, the sound absorption effect can be improved.

Further, in the present embodiment, a plurality of hollow portions F are provided in the width direction of the main body portion 12, and each of the two second hollow portions FB is provided with different positions in the longitudinal direction in the main body portion 12. On the other hand, air column resonance holes H1 and H2 are provided. With such a configuration, sound in a plurality of frequency bands can be selectively absorbed. Therefore, it is possible to more preferably take measures against the sound of a specific frequency band generated when the railway vehicle is traveling.

FIG. 4 is a plan view showing a modified example of the luggage rack. In the luggage rack 21 shown in the figure, the configuration of the air column resonance hole H is different from that of the above embodiment. More specifically, in the luggage rack 21, the wall portion 14 is not provided on the one end surface 12c of the main body portion 12 in the longitudinal direction, and the one end surface 12c resonates with the air column so that the hollow portion F is exposed. It is an open end provided with a hole H. Further, the other end surface 12d of the main body portion 12 in the longitudinal direction is a closed end provided with a wall portion 14 so that the hollow portion F is not exposed. In the air column resonance hole H, the sound absorbing material 15 is arranged inside the hole in a range of about 10 mm to 20 mm from the end of the opening. Further, even at the closed end, the sound absorbing material 16 is arranged in a range of about 10 mm to 20 mm from the wall portion 14.

In this embodiment, the distance L from the air column resonance hole portion H, which is the open end, to the other end surface 12d, which is the closed end, is variable depending on the length of the main body portion 12, and the frequency band for sound absorption can be easily adjusted. For example, when the length L of the main body 12 is 300 mm to 1500 mm, the frequency of the sound absorbed by the air column resonance hole H is estimated to be about 57 Hz to 280 Hz.

FIG. 5 is a plan view showing another modification of the luggage rack. In the luggage rack 31 shown in the figure, the configuration of the air column resonance hole portion H is further different from that of the above embodiment. More specifically, in the luggage rack 31, the one end surface 12c and the other end surface 12d of the main body portion 12 in the longitudinal direction are not provided with the wall portion 14, and the one end surface 12c and the other end surface 12d are both hollow. It is an open end provided with an air column resonance hole H so that the portion F is exposed. In the air column resonance hole H, the sound absorbing material 15 is arranged inside the hole in a range of about 10 mm to 20 mm from the end of the opening.

Also in this form, the distance L from the air column resonance hole portion H, which is the open end, to the other end surface 12d, which is the closed end, is variable depending on the length of the main body portion 12, and the frequency band for sound absorption can be easily adjusted. When the one end surface 12c and the other end surface 12d of the main body 12 in the longitudinal direction are open ends, the period λ of the standing wave generated between the air column resonance hole portion H and the open end and the hollow portion F A relational expression of L = 1 / 2λ (= 2 / 2λ, = 3 / 2λ ...) is established between the length (distance from the air column resonance hole H to the open end) L. Therefore, for example, when the length L of the main body 12 is 500 mm to 3000 mm, the frequency of the sound absorbed by the air column resonance hole H is estimated to be about 57 Hz to 340 Hz.

Next, a verification test of the sound absorption effect of the luggage rack will be described. In this verification test, the frequency characteristics of the sound absorption effect were determined for each of sample A according to the form shown in FIG. 3, sample B according to the form shown in FIG. 4, and sample C according to the form shown in FIG. It was calculated by simulation. In each of the samples A to C, simulations were performed for each of the cases where the sound absorbing material was provided at the open end of the air column resonance hole and the case where the sound absorbing material was not provided.

FIG. 6 is a diagram showing a verification result for sample A. In sample A, the length of the main body of the luggage rack was 1040 mm, and both one end surface and the other end surface in the longitudinal direction of the main body were closed ends. Further, on the opposite surface of the main body portion, an air column resonance hole portion having a circular cross section was arranged at the center of the hollow portion (distance L = 520 mm from the closed end). The horizontal axis of FIG. 6 is the frequency, and the vertical axis is the sound pressure level. One scale on the vertical axis is 5 dB. As shown in the figure, in sample A, it can be confirmed that the sound absorption peak exists in the vicinity of 130 Hz, and that the sound absorption effect of about 21 dB is obtained in the vicinity of the peak with respect to the reference value S of the sound pressure. When the sound absorbing material was provided, the sound absorbing effect near the peak was similar to that when the sound absorbing material was not provided, but a slight improvement in the sound absorbing effect was observed in other frequency bands.

FIG. 7 is a diagram showing a verification result for sample B. In sample B, the length of the main body of the luggage rack was 1040 mm, one end surface of the main body in the longitudinal direction was an open end, and the other end surface was a closed end. The horizontal axis of FIG. 7 is the frequency, and the vertical axis is the sound pressure level. One scale on the vertical axis is 5 dB. As shown in the figure, in sample B, a sound absorption peak exists in the vicinity of 80 Hz, and it can be confirmed that there is a sound absorption effect of about 19 dB with respect to the reference value S of the sound pressure in the vicinity of the peak. Further, in sample B, a sound absorption peak exists in the vicinity of 250 Hz, and it can be confirmed that there is a sound absorption effect of about 20 dB with respect to the reference value S of the sound pressure in the vicinity of the peak. The peak corresponds to L = 3/4 λ. When the sound absorbing material is provided, the sound absorbing effect near the peak is about the same as that when the sound absorbing material is not provided, but an improvement in the sound absorbing effect of up to about 5 dB is observed in other frequency bands.

FIG. 8 is a diagram showing the verification results for sample C. In sample C, the length of the main body of the luggage rack was 1040 mm, and both one end surface and the other end surface in the longitudinal direction of the main body were open ends. The horizontal axis of FIG. 8 is the frequency, and the vertical axis is the sound pressure level. One scale on the vertical axis is 5 dB. As shown in the figure, in sample B, it can be confirmed that the sound absorption peak exists in the vicinity of 80 Hz, and that the sound absorption effect of about 20 dB is obtained in the vicinity of the peak with respect to the reference value S of the sound pressure. When the sound absorbing material is provided, the sound absorbing effect near the peak is about the same as that when the sound absorbing material is not provided, but an improvement in the sound absorbing effect of up to about 5 dB is observed in other frequency bands.

The present invention is not limited to the above embodiment. For example, in the above embodiment, a plurality of hollow portions F having a triangular cross section are formed in the internal space of the main body portion 12 by the truss-shaped ribs 13, but the cross-sectional shapes of the hollow portions F are rectangular in cross section, circular in cross section, and cross section. It may be another shape such as a polygon. Further, the rib 13 is not always provided, and the hollow portion F may be a single number. Further, in the above embodiment, the flat main body portion 12 is illustrated, but a frame body or a rod member used for fixing the railroad vehicle 1 to the side structure 3 may be integrated with the main body portion 12.

Further, in the form shown in FIGS. 2 and 3, the air column resonance holes H1 and H2 having a circular cross section are provided on the opposite surface 12b of the main body 12, but as in the luggage rack 41 shown in FIG. Instead of the air column resonance holes H1 and H2, a notch 20 for exposing a plurality of hollow portions F may be provided on the opposite surface 12b. In the example of FIG. 9, the notch 20 extends in the width direction of the main body 12 at a position centered in the longitudinal direction of the main body 12. At the formation position of the notch portion 20, about 1/3 of the mounting surface 12a and each rib 13 forming the plurality of hollow portions F on the mounting surface 12a side remains. As a result, the plurality of hollow portions F are in a state of communicating with the outside, and the air column resonance hole portion H is formed. In the air column resonance hole H, the sound absorbing material 15 is arranged inside the hole in a range of about 10 mm to 20 mm from the end of the opening. Further, even at the closed end, the sound absorbing material 16 is arranged in a range of about 10 mm to 20 mm from the wall portion 14.

Even in such a form, the frequency band for sound absorption can be easily adjusted depending on the position of the air column resonance hole portion H. Since the frequency band for sound absorption is adjusted according to the position of the air column resonance hole portion H, the length of the main body portion 12 can be made relatively long. Therefore, it is possible to reduce the number of luggage racks 11 arranged in the longitudinal direction of the railroad vehicle 1. Further, since the air column resonance hole portion H is provided on the surface opposite to the mounting surface 12a, the air column resonance hole portion H faces downward when applied to the railway vehicle 1. Therefore, the sound absorption effect can be improved. In the example of FIG. 9, the notch 20 extends in the width direction of the main body 12, but the notch 20 may extend diagonally with respect to the width direction of the main body 12. Further, in the example of FIG. 9, the notch 20 is provided at the center of the main body 12 in the longitudinal direction, but the formation position of the notch 20 is not limited to the center of the longitudinal direction, and the sound to be absorbed is not limited to the center. It can be set arbitrarily according to the target value of the frequency band.

1 ... Railway vehicle, 3 ... Side structure, 11,21,31,41 ... Luggage rack, 12 ... Main body, 12a ... Mounting surface, 12b ... Opposite surface, 12c ... One end surface, 12d ... Other end surface, 15, 16 ... Sound absorbing material, 20 ... Notch, F ... Hollow, H ... Air column resonance hole.

Claims (8)

It has a main body with a mounting surface on which luggage is placed along the longitudinal direction.
The main body portion has a hollow portion extending in the longitudinal direction and an air column resonance hole portion that communicates the hollow portion with the outside .
Both one end surface and the other end surface of the main body portion in the longitudinal direction are closed ends provided with wall portions so that the hollow portion is not exposed.
The air column resonance hole portion is provided on the surface of the main body portion opposite to the above-described mounting surface.
The main body portion has a plurality of the hollow portions.
The air column resonance hole portion is a luggage rack provided for the plurality of hollow portions so that the positions of the main body portion in the longitudinal direction are different from each other. It has a main body with a mounting surface on which luggage is placed along the longitudinal direction.
The main body portion has a hollow portion extending in the longitudinal direction and an air column resonance hole portion that communicates the hollow portion with the outside .
Both one end surface and the other end surface of the main body portion in the longitudinal direction are closed ends provided with wall portions so that the hollow portion is not exposed.
The air column resonance hole portion is provided on the surface of the main body portion opposite to the above-described mounting surface.
The main body portion has a plurality of the hollow portions.
The air column resonance hole portion is a luggage rack composed of notches that expose the plurality of hollow portions. It has a main body with a mounting surface on which luggage is placed along the longitudinal direction.
The main body portion has a hollow portion extending in the longitudinal direction and an air column resonance hole portion that communicates the hollow portion with the outside .
One end surface of the main body portion in the longitudinal direction is an open end provided with the air column resonance hole portion so that the hollow portion is exposed.
The other end surface of the main body portion in the longitudinal direction is a luggage rack having a closed end provided with a wall portion so that the hollow portion is not exposed. It has a main body with a mounting surface on which luggage is placed along the longitudinal direction.
The main body portion has a hollow portion extending in the longitudinal direction and an air column resonance hole portion that communicates the hollow portion with the outside .
The one end surface and the other end surface of the main body portion in the longitudinal direction are both open ends provided with the air column resonance holes so that the hollow portion is exposed . The luggage rack according to claim 1 or 2 , wherein a sound absorbing material is arranged at at least one of the open end and the closed end of the air column resonance hole portion. The luggage rack according to claim 3 , wherein a sound absorbing material is arranged at at least one of the open end and the closed end. The luggage rack according to claim 4 , wherein a sound absorbing material is arranged on at least one of the open ends on one side and the other side of the main body. A railroad vehicle in which the luggage rack according to any one of claims 1 to 7 is fixed to the inner upper part of the side structure.

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