Railway vehicle

Abstract

To provide a railway vehicle equipped with a return duct installed in a ceiling, which returns air in a passenger compartment to an air conditioning unit provided in a roof structure, and which effectively reduces low-frequency noise generated by the air conditioning unit to enhance quietness within the passenger compartment.SOLUTION: A railway vehicle 10 is equipped with an air conditioning unit KT provided in a roof structure YK, and a return duct KD1 installed in a ceiling. This duct returns air RA in a passenger compartment 1 from an air intake section 22 formed in a ceiling panel 2 to a RA opening KT2 of the air conditioning unit via a curved flow path KD11. On a rear side of the ceiling panel forming a lower surface of the return duct, a sound-reflecting plate 4 is provided at a lower vehicle position opposite the RA opening at a position spaced apart from the ceiling panel toward an upper vehicle side, with a plurality of through holes 41 formed therein. A spacing distance d1 between the ceiling panel and the sound-reflecting plate is formed to gradually change.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a railway vehicle, and more particularly to a railway vehicle equipped with a return duct in the ceiling for returning air from inside the passenger compartment to an air conditioner provided in the roof structure. [Background technology]

[0002] Conventionally, return ducts that return air from the passenger compartment to air conditioners installed in the roof structure have often connected the return air opening (hereinafter referred to as the "RA opening") of the air conditioner to the intake port formed in the ceiling panel in a straight line in the vertical direction of the vehicle, for reasons such as reducing pressure loss within the duct. However, in this case, air conditioner noise (such as noise from a compressor operating) is easily transmitted from the RA opening through the straight return duct into the passenger compartment, causing problems with noise inside the passenger compartment when the air conditioner is operating.

[0003] In this regard, for example, Patent Document 1 discloses a railway vehicle 100, as shown in Fig. 6, which includes a roof structure 103 having an air conditioner 101 mounted thereon and having a first opening 102 through which air can be ventilated to the air conditioner 101; a ceiling member 105 attached to the underside of the roof structure 103 to define the ceiling of a passenger compartment 104 and having a second opening 106 through which air can be ventilated from the passenger compartment 104; and a return duct 107 connecting the first opening 102 and the second opening 106 and forming a flow path connecting the first opening 102 and the second opening 106, wherein the second opening 106 is not aligned with the first opening 102 in the height direction of the railway vehicle 100 but is offset in the longitudinal direction or width direction of the railway vehicle 100. A filter 106a and a perforated plate 106b are provided in the second opening 106. Furthermore, a sound-absorbing rectifying member 108 is provided in the plate material forming the return duct 107 to smooth the flow of air 109 flowing through the flow path. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-144167 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the return duct 107 of the railway vehicle 100 in Patent Document 1 has the following problem. That is, because sound-absorbing rectifying members 108 that smooth the flow of air 109 flowing through the flow path are arranged on the plate material that makes up the return duct 107, noise from the air conditioner 101 is also smoothly propagated within the return duct 107 along the rectifying members 108, resulting in a problem that noise inside the passenger compartment 104 while the air conditioner is operating cannot be sufficiently reduced. In addition, because the sound-absorbing rectifying members 108 are made of a sound-absorbing material (such as a porous material) that is formed in a plate or triangular shape, they can generally effectively reduce noise in the mid- to high-frequency range, but cannot sufficiently reduce low-frequency noise with a frequency of approximately 400 to 500 Hz or less, such as noise generated when the compressor of the air conditioner 101 is operating.

[0006] The present invention has been made to solve such problems, and aims to provide a railway vehicle equipped with a return duct in the ceiling that returns air inside the passenger compartment to an air conditioner installed in the roof structure, effectively reducing low-frequency noise generated by the air conditioner and improving quietness inside the passenger compartment. [Means for solving the problem]

[0007] In order to achieve the above object, a railway vehicle according to the present invention has the following configuration. (1) A railway vehicle having an air conditioner installed in the roof structure and a return duct in the ceiling space that returns the air in the passenger compartment from an air intake formed in the ceiling panel to the RA opening of the air conditioner through a curved flow path, A sound reflecting plate having a plurality of through holes formed therein is provided on the rear surface side of the ceiling panel that constitutes the lower surface of the return duct, at a position below the vehicle facing the RA opening and spaced apart from the ceiling panel above the vehicle, The distance between the ceiling panel and the sound reflecting plate is formed so as to gradually change.

[0008] In the present invention, a sound reflecting plate with multiple through holes is provided on the back side of the ceiling panel that forms the underside of the return duct, at a position below the vehicle facing the RA opening and spaced above the ceiling panel, so that some of the mid- to high-frequency to low-frequency noise generated by the air conditioner can be reflected by the sound reflecting plate toward the RA opening as it propagates from the RA opening to the air intake port of the ceiling panel.As a result, it is possible to suppress not only mid- to high-frequency noise but also low-frequency noise from propagating into the passenger compartment.

[0009] Furthermore, sound waves from the air conditioner that pass through the holes in the sound reflecting plate are attenuated in the gap between the ceiling panel and the sound reflecting plate using the sound absorption principle of a Helmholtz resonator, reducing noise transmitted into the passenger compartment. The distance between the ceiling panel and the sound reflecting plate is designed to gradually change, allowing for sound absorption across a wide range of frequencies. As the distance increases, the resonant frequency between the ceiling panel and the sound reflecting plate expands to a low-frequency range of approximately 400 to 500 Hz, effectively reducing low-frequency noise. This increases the quietness of the passenger compartment.

[0010] Therefore, according to the present invention, it is possible to provide a railway vehicle equipped with a return duct in the ceiling that returns air inside the passenger compartment to an air conditioner installed in the roof structure, and that effectively reduces low-frequency noise generated by the air conditioner, thereby improving quietness inside the passenger compartment.

[0011] (2) In the railway vehicles described in (1), The return duct is characterized by being provided with a second sound reflecting plate disposed near the intake port.

[0012] In the present invention, the return duct is provided with a second sound reflecting plate disposed near the air intake, so that noise generated by the air conditioner that is not reflected by the sound reflecting plate toward the RA opening is reflected and attenuated by the second sound reflecting plate, thereby suppressing propagation from the air intake into the passenger compartment, thereby further improving quietness inside the passenger compartment.

[0013] (3) In the railway vehicles described in (2), The second sound reflecting plate is characterized in that it extends obliquely upward and laterally from the vehicle width direction end of the main body of the sound reflecting plate in which the through hole is formed.

[0014] In the present invention, the second sound reflecting plate extends diagonally upward from the vehicle width direction end of the main body of the sound reflecting plate where the through hole is formed, so that noise generated by the air conditioner that is not reflected by the sound reflecting plate toward the RA opening can be reflected by the second sound reflecting plate toward the RA opening, thereby further attenuating low-frequency noise propagating from the air intake into the passenger compartment, thereby more effectively improving quietness inside the passenger compartment.

[0015] (4) In the railway vehicles described in (2), The second sound reflecting plate is formed so as to divide the flow path into a plurality of parts above and below the vehicle.

[0016] In the present invention, the second sound reflecting plates are formed to divide the flow path into multiple sections at the top and bottom of the vehicle, so there is almost no pressure loss in the flow path. Furthermore, noise generated by the air conditioner that is not reflected toward the RA opening by the sound reflecting plates can be further attenuated by repeatedly reflecting it upward and downward by the second sound reflecting plates that divide the flow path into multiple sections at the top and bottom of the vehicle. Therefore, there is almost no pressure loss in the flow path, and low-frequency noise propagating from the intake port into the passenger compartment can be further attenuated. As a result, quietness in the passenger compartment can be improved even more effectively.

[0017] (5) In the railway vehicles described in (4), The second sound reflecting plate is characterized in that a guide portion is formed to guide the air flowing through the flow path toward the RA opening side.

[0018] In the present invention, the second sound reflecting plate is formed with a guide portion that guides the air flowing through the flow path toward the RA opening, thereby reducing pressure loss in the flow path by the guide portion. Furthermore, noise generated by the air conditioner that is not reflected toward the RA opening by the sound reflecting plate can be reflected toward the sound reflecting plate by the guide portion, thereby further attenuating the noise. Therefore, pressure loss in the flow path can be reduced while still more effectively improving quietness in the passenger compartment.

[0019] (6) In a railway vehicle described in any one of (1) to (5), The sound reflecting plate includes a plurality of partition walls extending toward the rear surface of the ceiling panel, Between the sound reflecting plate and the ceiling panel, there are provided a plurality of resonance chambers, each of which is partitioned by the partition wall and has a different resonance frequency in the low frequency range.

[0020] In the present invention, the sound reflecting plate is provided with a plurality of partition walls extending to the rear side of the ceiling panel, and a plurality of resonance chambers, each with a different low-frequency resonance frequency, are provided between the sound reflecting plate and the ceiling panel, which are partitioned by the partition walls. This makes it possible to reduce low-frequency noise from the air conditioner over a wider frequency range, thereby more effectively improving quietness inside the passenger compartment. [Effects of the Invention]

[0021] According to the present invention, it is possible to provide a railway vehicle equipped with a return duct in the ceiling that returns air inside the passenger compartment to an air conditioner installed in the roof structure, effectively reducing low-frequency noise generated by the air conditioner and improving quietness inside the passenger compartment. [Brief explanation of the drawings]

[0022] [Figure 1] 1 is a schematic side view of a railway vehicle according to one aspect of an embodiment of the present invention. [Figure 2] 2 is a cross-sectional view taken along the line AA in FIG. 1. [Figure 3] FIG. 3 is a cross-sectional view taken along the line BB in FIG. 2, showing a first example of the present embodiment. [Figure 4] FIG. 5 is a cross-sectional view taken along the line BB in FIG. 2, showing a second example of the present embodiment. [Figure 5] FIG. 3 is a cross-sectional view taken along the line BB in FIG. 2, showing a modification of the second example of the present embodiment. [Figure 6] FIG. 1 is a schematic cross-sectional view of a return duct of a railway vehicle described in Patent Document 1. DETAILED DESCRIPTION OF THE INVENTION

[0023] <Configuration of this railway vehicle> Next, first and second examples of a railway vehicle according to one aspect of an embodiment of the present invention will be described in detail with reference to the drawings. Fig. 1 shows a schematic side view of a railway vehicle according to one aspect of an embodiment of the present invention. Fig. 2 shows a cross-sectional view taken along line AA in Fig. 1. Fig. 3 shows a cross-sectional view taken along line BB in Fig. 2 of the first embodiment of the present invention. Fig. 4 shows a cross-sectional view taken along line BB in Fig. 2 of the second embodiment of the present invention. Fig. 5 shows a cross-sectional view taken along line BB in Fig. 2 of a modified example of the second embodiment of the present invention.

[0024] (First Example) As shown in FIG. 1 , the railway vehicle 10 of the first embodiment includes an underframe DW supported by a pair of front and rear bogies DS running on rails RL, end structures TK erected at the front and rear ends of the underframe DW, side structures GK erected at both ends of the underframe DW, and a roof structure YK connected to the upper ends of the end structures TK and the side structures GK. The side structures GK are also formed with side windows GM of various sizes, a passenger side door GT1 through which passengers board and disembark, and a crew side door GT2 through which the driver and other personnel board and disembark. Underfloor equipment KZ is attached to the underframe DW. An air conditioner KT is attached to the roof structure YK. Here, one air conditioner KT is attached to the roof structure YK near the center of the vehicle's longitudinal direction, but multiple air conditioners may be attached.

[0025] As shown in FIGS. 1 to 3, the railway vehicle 10 is provided with an air conditioner KT on the roof structure YK, and a return duct KD1 is provided above the ceiling for returning air RA from the passenger compartment 1 from an air intake 22 formed in the ceiling panel 2 to an RA opening KT2 of the air conditioner KT via a curved flow path KD11. A roll filter device 6 having a rollable filter section 61 is disposed at the upper end of the return duct KD1. The air RA from the passenger compartment 1 that has passed through the air intake 22 is returned to the RA opening KT2 of the air conditioner KT after foreign matter and the like have been removed by the filter section 61 of the roll filter device 6. The air intake 22 may be divided into multiple sections in the longitudinal direction of the vehicle (rail direction).

[0026] The return duct KD1 is composed of an upper duct section 3 located above the ceiling and a ceiling panel 2. The upper duct section 3 and the ceiling panel 2 are fixed separately at the top and bottom to the inner frame YK1 of the roof structure YK. Here, the inner frame YK1 has a flanged hat-shaped cross section with a horizontal flange YK11 at its lower end. The upper duct section 3 is formed with a vertical wall section 31 and a horizontal wall section 32 in a V-shape, and functions to bend the flow path KD11 from the vehicle vertical direction to the vehicle width direction. The vertical wall section 31 of the upper duct section 3 and the locking fitting 23 of the ceiling panel 2 are fixed separately at the top and bottom to the flange YK11 of the inner frame YK1. A seal material 25 is installed between the locking fitting 23 and the flange YK11 of the inner frame YK1. The horizontal wall section 32 of the upper duct section 3 is adjacent to or abuts against the frame 62 of the roll filter device 6.

[0027] The ceiling panel 2 is made of a resin material or the like and is shaped into a predetermined shape in the center of the ceiling. The ceiling panel 2 has an upwardly curved portion 2H that protrudes in an arc shape upward from both ends in the vehicle width direction where the air intake port 22 is formed, and a downwardly curved portion 2T that protrudes in an arc shape downward from both ends in the vehicle width direction, which are formed at different positions in the vehicle longitudinal direction, thereby increasing the rigidity of the ceiling panel 2 in the middle in the vehicle width direction. In this way, increasing the rigidity of the ceiling panel 2 itself suppresses vibration of the ceiling panel 2 and makes it difficult for noise SO from the air conditioner KT to propagate into the passenger compartment 1.

[0028] In addition, air conditioning ducts KD, which blow conditioned air supplied from the supply port KT1 of the air conditioner KT into the passenger compartment 1, are provided in the ceiling space on the front and rear sides of the return duct KD1. The return duct KD1 and the air conditioning duct KD are formed to have the same or similar dimensions in the vehicle width direction. Therefore, the undersides of the return duct KD1 and the air conditioning duct KD can be formed by a common ceiling panel 2. Furthermore, a heat insulating material 24 is attached to the back side of the ceiling panel 2. This heat insulating material 24 can also serve as sound absorbing material. Furthermore, a lighting interior panel 7 equipped with lighting fixtures (not shown) is attached to the end of the ceiling panel 2 in the vehicle width direction, and a side ceiling panel 5 joined to the interior panel of the side structure GK is attached to the end of the lighting interior panel 7 closer to the outside of the vehicle width direction.

[0029] Furthermore, on the rear surface of the ceiling panel 2 that forms the underside of the return duct KD1, at a position below the vehicle facing the RA opening KT2 and spaced apart above the vehicle from the ceiling panel 2, there is provided a sound reflecting panel 4 with a plurality of through holes 41 formed therein. Therefore, part of the noise SO from the mid-high to low frequency ranges generated by the air conditioner KT can be reflected by the sound reflecting panel 4 toward the RA opening KT2 on its way from the RA opening KT2 to the air intake port 22 of the ceiling panel 2. Therefore, it is possible to suppress the propagation of not only mid-high frequency noise SO but also low frequency noise SO into the passenger compartment 1.

[0030] Here, the sound reflecting plate 4 has a vertex at the center CL in the vehicle width direction, and slopes gently downward as it moves toward the sides of the vehicle (toward the right and left of the vehicle), forming a gentle mountain-shaped cross section. By forming the sound reflecting plate 4 into a gentle mountain-shaped cross section, it is possible to reflect more of the noise SO generated by the air conditioner KT toward the RA opening KT2, while allowing the air RA inside the passenger compartment 1 drawn in from the air intake port 22 to return smoothly to the RA opening KT2. The angle of inclination of the sound reflecting plate 4 with respect to the horizontal plane is preferably about 5 to 10 degrees. In this case, it is possible to reflect more of the noise SO toward the RA opening KT2, while ensuring the necessary flow path space in the return duct KD1.

[0031] Furthermore, sound waves from the air conditioner KT that pass through the through holes 41 in the sound reflecting panel 4 are attenuated in the gap between the ceiling panel 2 and the sound reflecting panel 4 by the sound absorption principle of a Helmholtz resonator, thereby reducing the noise SO propagating into the passenger compartment 1. The distance d1 between the ceiling panel 2 and the sound reflecting panel 4 gradually changes. Specifically, the distance d1 between the sound reflecting panel 4, which has a gently sloping mountain-shaped cross section, and the upwardly curved portion 2H that protrudes in an arc upward from the vehicle, or the downwardly curved portion 2T that protrudes in an arc downward from the vehicle, gradually changes in the vehicle width direction. This enables sound absorption across a wide range of frequencies. Furthermore, as the distance d1 increases, the resonant frequency between the ceiling panel 2 and the sound reflecting panel 4 can be expanded to a low-frequency range of approximately 400 to 500 Hz or less, effectively reducing low-frequency noise. As a result, quietness within the passenger compartment 1 can be improved.

[0032] Therefore, according to the present railway vehicle 10, a railway vehicle 10 can be provided that is equipped with a return duct KD1 in the ceiling that returns the air RA in the passenger compartment 1 to the air conditioner KT provided in the roof structure YK, and that effectively reduces the low-frequency noise SO generated from the air conditioner KT, thereby improving quietness in the passenger compartment 1.

[0033] Furthermore, in the present railway vehicle 10, the return duct KD1 is preferably provided with a second sound reflecting plate 42 arranged near the air intake port 22. In this case, noise SO1 generated by the air conditioner KT that is not reflected by the sound reflecting plate 4 toward the RA opening KT2 is reflected by the second sound reflecting plate 42 toward the RA opening KT2, and can be prevented from propagating from the air intake port 22 into the passenger compartment 1. This makes it possible to further improve quietness inside the passenger compartment 1.

[0034] Furthermore, in the present railway vehicle 10, the second sound reflecting panel 42 preferably extends obliquely upward and laterally (in a direction inclined upward toward the outside in the vehicle width direction) from the vehicle width direction end of the main body 4H of the sound reflecting panel 4, where the through hole 41 is formed. In this case, noise SO1 generated by the air conditioner KT that is not reflected by the sound reflecting panel 4 toward the RA opening KT2 is reflected by the second sound reflecting panel 42 toward the RA opening KT2, thereby further attenuating low-frequency noise SO1 propagating from the air intake 22 into the passenger compartment 1. This further effectively improves quietness inside the passenger compartment 1. The intersection angle of the second sound reflecting panel 4 with respect to the sound reflecting panel 4 is preferably formed at an obtuse angle of approximately 120 to 150 degrees. In this case, the amount of bending of the flow path KD11 is not significantly increased, thereby minimizing an increase in pressure loss. Furthermore, the tip of the second sound reflecting panel 42 is preferably bent obliquely downward toward the air intake 22 of the ceiling panel 2. In this case, the tip of the second sound reflecting plate 42 allows the air RA that has flowed in from the intake port 22 to return more smoothly to the RA opening KT2 side.

[0035] (Second Example) 1, 2, 4, and 5, the railway vehicle 10B of the second embodiment is equipped with an air conditioner KT on the roof structure YK and a return duct KD1 above the ceiling that returns air RA from the passenger compartment 1 from an air intake 22 formed in the ceiling panel 2 to an RA opening KT2 of the air conditioner KT via a curved flow path KD11. The back side of the ceiling panel 2 that forms the underside of the return duct KD1 is equipped with a sound reflecting plate 4 with multiple through holes 41 at a position below the vehicle facing the RA opening KT2 and spaced apart from the ceiling panel 2 toward the vehicle top, and the distance d1 between the ceiling panel 2 and the sound reflecting plate 4 is gradually changed. The return duct KD1 is also equipped with a second sound reflecting plate 43 (431, 432) located near the air intake 22. The above features are common to the railway vehicle 10 of the first embodiment described above. Here, the same reference numerals are used to denote the components common to the railway vehicle 10 of the first embodiment, and the explanation thereof will be omitted in principle, and the explanation will focus on the components that are different.

[0036] In the railway vehicle 10B of the second embodiment, the second sound reflecting panels 43 (431, 432) are formed to divide the flow path KD11 into multiple sections above and below the vehicle. For example, as shown in FIG. 4 , the second sound reflecting panels 43 include a lower reflecting panel 431 extending horizontally above the vehicle width direction end of the sound reflecting panel 4, and an upper reflecting panel 432 extending horizontally above the lower reflecting panel 431 and extending to the vertical wall portion 31 of the upper duct portion 3. In this case, the air RA in the passenger compartment 1 sucked through the air intake port 22 of the ceiling panel 2 comes into contact with the upper reflecting panel 432 and bends inward in the vehicle width direction. Then, the air RA flows along the gap between the upper reflecting panel 432 and the lower reflecting panel 431 and the gap between the lower reflecting panel 431 and the sound reflecting panel 4, resulting in almost no increase in pressure loss. Preferably, the upper reflecting panel 432 is curved downward in an arc shape near the vertical wall portion 31. In this case, the pressure loss in the vicinity of the vertical wall portion 31 can be further reduced.

[0037] In contrast, noise SO1 generated by the air conditioner KT that is not reflected toward the RA opening KT2 by the sound reflecting plate 4 is repeatedly reflected upward and downward by the gap between the upper reflecting plate 432 and the lower reflecting plate 431, and by the gap between the lower reflecting plate 431 and the sound reflecting plate 4, and is thereby attenuated. In this way, noise SO1 that is not reflected toward the RA opening KT2 by the sound reflecting plate 4 is repeatedly reflected upward and downward by the second sound reflecting plates 43 (431, 432) that divide the flow path KD11 into multiple parts at the top and bottom of the vehicle, thereby being further attenuated. Therefore, low-frequency noise SO1 propagating from the intake port 22 into the passenger compartment 1 can be further attenuated without substantially increasing the pressure loss in the flow path KD11. As a result, quietness inside the passenger compartment 1 can be improved even more effectively. Here, the second sound reflecting plates 43 (431, 432) are formed so as to divide the flow path KD11 into two parts at the top and bottom of the vehicle, but this is not limitative and the flow path KD11 may be divided into three or more parts.

[0038] Furthermore, in the present railway vehicle 10C of the modified example of the second embodiment, as shown in FIG. 5, the second sound reflecting plate 43 preferably has a guide portion 433 formed thereon that guides the air RA flowing through the flow path KD11 toward the RA opening KT2. The guide portion 433 extends obliquely upward and inward from the inner end of the lower reflecting plate 431 in the vehicle width direction. In this case, the guide portion 433 smooths the flow of the air RA, thereby reducing pressure loss in the flow path KD11. Furthermore, noise SO1 generated by the air conditioner KT that is not reflected toward the RA opening KT2 by the sound reflecting plate 4 can be reflected toward the sound reflecting plate 4 by the guide portion 433, thereby further attenuating the noise. Therefore, the quietness inside the passenger compartment 1 can be more effectively improved while reducing pressure loss in the flow path KD11.

[0039] Furthermore, in the present railway vehicle 10C of the modified second embodiment, as shown in FIG. 5, the sound reflecting plate 4 is provided with a plurality of partition walls 44 extending to the rear surface side of the ceiling panel 2, and it is preferable to provide resonance chambers 4K (4Ka, 4Kb) between the sound reflecting plate 4 and the ceiling panel, which are partitioned by the partition walls 44 and have different low-frequency resonance frequencies (for example, a resonance frequency of 400 Hz and a resonance frequency of 500 Hz). In this case, the low-frequency noise SO of the air conditioner KT can be reduced over a wider frequency range. As a result, quietness inside the passenger compartment 1 can be improved even more effectively. This can also be applied to the present railway vehicle 10 of the first embodiment.

[0040] Here, the sound reflecting plate 4 is formed with different plate thicknesses t1 and t2 for each resonance chamber 4K (4Ka and 4Kb), and through holes 41 (41a and 41b) with different hole diameters b1 and b2 are formed. In this case, even if the volumes of the resonance chambers 4K (4Ka and 4Kb) are the same, the volumes of the through holes 41 (41a and 41b) are different, so that the resonance frequencies of the resonance chambers 4K can be varied. Furthermore, by standardizing the volumes of the resonance chambers 4K (4Ka and 4Kb), many compact resonance chambers 4K can be formed. As a result, air conditioning ducts KD are provided on the front and rear sides of the return duct KD1, and the return duct KD1, which is formed in a narrow area, can reduce low-frequency noise SO over a wider frequency range. Needless to say, the railway vehicles 10, 10B, and 10C can be further modified in various forms without departing from the spirit and scope of the present invention.

[0041] <Action and effect> According to the railway cars 10, 10B, and 10C according to the present embodiment described above in detail, the back surface of the ceiling panel 2 constituting the underside of the return duct KD1 is provided with a sound reflecting panel 4 having a plurality of through holes 41 formed therein, at a position below the vehicle that faces the RA opening KT2 and spaced apart above the vehicle from the ceiling panel 2. This allows a portion of the mid- to high-frequency to low-frequency noise SO generated by the air conditioner KT to be reflected by the sound reflecting panel 4 toward the RA opening KT2 on its way from the RA opening KT2 to the air intake port 22 of the ceiling panel 2. Therefore, it is possible to suppress the propagation of not only mid- to high-frequency noise SO but also low-frequency noise SO into the passenger compartment 1.

[0042] Furthermore, sound waves from the air conditioner KT that pass through the through holes 41 in the sound reflecting plate 4 are attenuated in the gap between the ceiling panel 2 and the sound reflecting plate 4 due to the sound absorption principle of a Helmholtz resonator, thereby reducing the noise SO propagating into the passenger compartment 1. The distance d1 between the ceiling panel 2 and the sound reflecting plate 4 is designed to gradually change, so that sound can be absorbed over a wide range of frequencies, and as the distance d1 increases, the resonant frequency between the ceiling panel 2 and the sound reflecting plate 4 can be expanded into the low-frequency range of approximately 400 to 500 Hz or less, effectively reducing low-frequency noise. This allows for increased quietness within the passenger compartment 1.

[0043] Therefore, according to this embodiment, it is possible to provide railway vehicles 10, 10B, and 10C that are equipped with a return duct KD1 in the ceiling that returns air RA in the passenger compartment 1 to an air conditioner KT provided on the roof structure YK, and that can effectively reduce low-frequency noise SO generated from the air conditioner KT and improve quietness in the passenger compartment 1.

[0044] Furthermore, according to this embodiment, the return duct KD1 is provided with the second sound reflecting plates 42, 43 (431, 432) arranged near the air intake port 22, so that noise SO1 generated by the air conditioner KT that is not reflected by the sound reflecting plates 4 to the RA opening KT2 side is reflected and attenuated by the second sound reflecting plates 42, 43 (431, 432), and can be prevented from propagating from the air intake port 22 into the passenger compartment 1. This makes it possible to further improve quietness inside the passenger compartment 1.

[0045] Furthermore, according to this embodiment, the second sound reflecting plate 42 extends diagonally upward from the vehicle width direction end of the main body 4H of the sound reflecting plate 4 where the through hole 41 is formed, so that noise SO1 generated by the air conditioner KT that is not reflected by the sound reflecting plate 4 to the RA opening KT2 side can be reflected by the second sound reflecting plate 42 to the RA opening KT2 side, thereby further attenuating the low-frequency noise SO1 propagating from the air intake port 22 into the passenger compartment 1. Therefore, the quietness inside the passenger compartment 1 can be improved even more effectively.

[0046] Furthermore, according to this embodiment, the second sound reflecting plates 43 are formed to divide the flow path KD11 into multiple parts at the top and bottom of the vehicle, so that there is almost no pressure loss in the flow path KD11. Furthermore, noise SO1 generated by the air conditioner KT that is not reflected toward the RA opening KT2 by the sound reflecting plates 4 is repeatedly reflected up and down by the second sound reflecting plates 43 (431, 432) that divide the flow path KD11 into multiple parts at the top and bottom of the vehicle, thereby further attenuating the noise SO1. Therefore, low-frequency noise SO1 propagating from the air intake port 22 into the passenger compartment 1 can be further attenuated without increasing the pressure loss in the flow path KD11. As a result, quietness inside the passenger compartment 1 can be further improved.

[0047] Furthermore, according to this embodiment, the second sound reflecting plate 43 is formed with a guide portion 433 that guides the air RA flowing through the flow path KD11 toward the RA opening portion KT2, thereby reducing the pressure loss in the flow path KD11 by the guide portion 433. Furthermore, noise SO1 generated by the air conditioner KT that is not reflected toward the RA opening portion KT2 by the sound reflecting plate 4 can be reflected toward the sound reflecting plate 4 by the guide portion 433, thereby further attenuating the noise. Therefore, the quietness in the passenger compartment 1 can be improved more effectively while reducing the pressure loss in the flow path KD11.

[0048] Furthermore, according to this embodiment, the sound reflecting plate 4 is provided with a plurality of partition walls 44 extending to the rear surface side of the ceiling panel 2, and a plurality of resonance chambers 4K having different low-frequency resonance frequencies are provided between the sound reflecting plate 4 and the ceiling panel, which are partitioned by the partition walls 44. As a result, the low-frequency noise SO of the air conditioner KT can be reduced over a wider frequency range. As a result, the quietness inside the passenger compartment 1 can be improved even more effectively. [Industrial Applicability]

[0049] The present invention can be used as a railway vehicle having a return duct in the ceiling that returns air from inside the passenger compartment to an air conditioner installed in the roof structure. [Explanation of symbols]

[0050] 1 guest room 2 Ceiling panels 3 Upper duct section 4 Sound reflector 4K resonance chamber 4H main body 10, 10B, 10C railcars 22 Air intake section 41 Through hole 42, 43 Second sound reflector 44 Bulkhead 433 Information Department KD1 return duct KD11 flow path KT air conditioner KT2 RA opening RA Air YK roof structure d1 Separation distance

Claims

1. A railway vehicle having an air conditioner mounted on a roof structure, and a return duct provided in the ceiling space for returning air from an air intake formed in a ceiling panel to an RA opening of the air conditioner through a curved flow path, a sound reflecting plate having a plurality of through holes formed therein, the sound reflecting plate being provided on the rear surface side of the ceiling panel that constitutes the lower surface of the return duct, at a position below the vehicle facing the RA opening and spaced apart from the ceiling panel above the vehicle; A railway vehicle, characterized in that the distance between the ceiling panel and the sound reflecting plate is formed so as to gradually change.

2. 2. The railway vehicle according to claim 1, A railway vehicle, characterized in that the return duct is provided with a second sound reflecting plate arranged near the intake port.

3. 3. The railway vehicle according to claim 2, The railway vehicle, wherein the second sound reflecting plate extends obliquely upward and laterally from the end in the vehicle width direction of the main body of the sound reflecting plate in which the through hole is formed.

4. 3. The railway vehicle according to claim 2, The railway vehicle, wherein the second sound reflecting plate is formed so as to divide the flow path into a plurality of sections above and below the vehicle.

5. 5. The railway vehicle according to claim 4, The railway vehicle, wherein the second sound reflecting plate is formed with a guide portion that guides the air flowing through the flow path toward the RA opening side.

6. The railway vehicle according to any one of claims 1 to 5, The sound reflecting plate includes a plurality of partition walls extending toward the rear surface of the ceiling panel, A railway vehicle characterized in that a plurality of resonance chambers having different low-frequency resonance frequencies are provided between the sound reflecting plate and the ceiling panel, the resonance chambers being separated by the partition wall.

Images