Rail vehicle

Abstract

To provide a railway vehicle capable of reducing noise of an air-conditioning ventilator propagated through a duct and discharged into the vehicle without narrowing a flow passage cross-sectional area or providing a complicated structure.SOLUTION: In a railway vehicle including a vehicle body, an air-conditioning ventilation device provided in the vehicle body, a duct connecting the vehicle body and the air-conditioning ventilation device, and a noise reduction structure, the noise reduction structure is disposed outside a flow path of air flowing from the inside of the vehicle to the air-conditioning ventilation device in the duct, and is excited at a predetermined frequency corresponding to a sound generated by the air-conditioning ventilation device.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a rail vehicle. [Background technology]

[0002] To date, various measures have been considered to reduce noise inside rail vehicles, such as vibration isolation of floorboards, sound insulation of interior panels, and sound absorption in ceilings and luggage racks.However, as noise inside rail vehicles is reduced, noise from indoor blowers (indoor fans) in air conditioning systems and ventilation blowers (ventilation fans) in ventilation systems (hereinafter referred to as air conditioning ventilation system noise), which have not previously been considered a problem, tend to become relatively more noticeable.

[0003] The noise generated by air conditioning and ventilation systems is caused by pressure fluctuations due to the steady, non-uniform pressure field formed around the rotor blades as the fan installed in the system rotates, and it is known that the frequency of the noise generated is proportional to the product of the number of blades in the rotor blades (fan) and the fan's rotation speed. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-138156 Summary of the Invention [Problem to be solved by the invention]

[0005] The noise generated by the fan rotation from the air conditioning ventilation system is transmitted inside the vehicle through ducts installed in the car body. Therefore, one idea to reduce noise is to take measures inside and outside the duct, but measures inside the duct raise concerns about increased pressure loss due to narrowing of the flow path, and measures outside the duct must be taken within the vehicle envelope, making it difficult to take sufficiently effective sound absorption measures.

[0006] Furthermore, as mentioned above, the frequency of the air conditioning and ventilation system noise that needs to be addressed varies depending on the fan rotation speed, so it is also a challenge to achieve noise reduction that corresponds to the ever-changing noise of the air conditioning and ventilation system.

[0007] In response to this, Patent Document 1 proposes installing active noise control equipment above the seat back, measuring noise with a sound collector, analyzing the measurement results, and generating anti-phase sound from a speaker to cancel out and reduce noise at the seat. However, rail vehicles and the like have many seats, so installing active noise control equipment in each seat is difficult from the perspective of not only the increased weight but also the man-hours required for installation and maintenance.

[0008] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a railway vehicle that reduces the noise of an air conditioning ventilation system that propagates through a duct and is released into the vehicle interior without narrowing the flow path cross-sectional area or providing a complex configuration. [Means for solving the problem]

[0009] In order to solve the above problems, one representative railway vehicle of the present invention is: A railway vehicle having a car body, an air conditioning / ventilation device provided in the car body, a duct connecting the car body and the air conditioning / ventilation device, and a noise reduction structure, The noise reduction structure is achieved by being positioned in the duct outside the flow path of air from the vehicle interior toward the air conditioning ventilation system, and by being excited at a predetermined frequency corresponding to the sound emitted by the air conditioning ventilation system. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a railway vehicle that reduces the noise of an air conditioning ventilation system that propagates through a duct and is released into the vehicle interior without narrowing the flow path cross-sectional area or providing a complex configuration. Problems, configurations, and effects other than those described above will become apparent from the following description of the embodiments. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a side view of a railway vehicle. [Figure 2] FIG. 2 is a cross-sectional view intersecting the longitudinal direction of the railway vehicle. [Figure 3] FIG. 3 is a cross-sectional view of a duct structure of a comparative example. [Figure 4] FIG. 4 is a cross-sectional view of a duct according to the first embodiment of the present invention. [Figure 5] FIG. 5 is a cross-sectional view of a duct showing a minimum equipment configuration according to the second embodiment of the present invention. [Figure 6] FIG. 6 is a flowchart showing a noise reduction mechanism according to the second embodiment of the present invention. [Figure 7] FIG. 7 is a cross-sectional view of a duct according to the second embodiment of the present invention. [Figure 8] FIG. 8 is a cross-sectional view of a location where a vibration speaker is attached according to the third embodiment of the present invention. [Figure 9] FIG. 9 is a cross-sectional view of a duct according to a fourth embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0012] Rail vehicles are vehicles that operate along laid tracks, and include railway vehicles, monorail vehicles, new transit system vehicles, streetcars, etc. Below, we will explain rail vehicles as a representative example of rail vehicles.

[0013] The longitudinal direction (rail direction) of railway vehicle 100 is the x direction, the width direction (sleeper direction) of railway vehicle 100 is the y direction, and the height direction intersecting the x direction and y direction is the z direction.

[0014] In the following embodiment, a ventilation duct through which fresh air from outside the vehicle flows will be described as an example, using a ventilation fan (ventilation fan) of a ventilation device provided under the floor of a railway vehicle. The ventilation fan may be an indoor fan (indoor fan) provided in an air conditioner and blowing conditioned air whose temperature and humidity have been adjusted into the vehicle interior, or the ventilation duct may be a conditioned air duct through which conditioned air whose temperature and humidity have been adjusted by an air conditioner flows.

[0015] 1 is a side view of a railway vehicle. Railway vehicle 100 has a carbody 110 and a pair of bogies 120 that support both x-direction ends of carbody 110 on which passengers and the like ride. Carbody 110 is composed of an underframe 111 that forms the floor surface, side structures 112 erected at both y-direction ends of underframe 111, end structures 114 erected at both x-direction ends of underframe 111, and a roof structure 113 placed on the upper ends of side structures 112 and end structures 114.

[0016] The railway vehicle 100 is composed of underfloor equipment such as an air conditioning unit or ventilation unit (hereinafter referred to as air conditioning ventilation unit) 10, and indoor equipment such as an air conditioning control unit (including power supply) 50 and a vehicle control unit 51, and runs along a track 130 laid on the ground.

[0017] 2 is a cross-sectional view intersecting the longitudinal direction of the railway vehicle, corresponding to cross-section AA shown in FIG. 1. An underframe 111 constituting a carbody 110 is provided with a duct 1 connecting the air conditioning ventilation system 10 and the interior space 11 of the car. In the first embodiment, the carbody 110 is provided with an airtight floor 200 constituting the underframe 111, a floor support 202 extending in the z direction from the upper surface of the airtight floor 200, and an upper floor 201 supported on the upper end of the floor support 202. A duct 1 is provided in the space between the airtight floor 200 and the upper floor 201, through which fresh air taken in from outside the car by the air conditioning ventilation system 10 flows. The duct 1 has a rectangular cross section perpendicular to the x direction.

[0018] The manner in which the duct 1 is provided is not limited to that of embodiment 1. The duct 1 may be provided, for example, in the space between the roof structure 113 and the ceiling provided on the vehicle interior side of the roof structure 113, or in the space between the side structure 112 and a side interior material provided on the vehicle interior side of the side structure 112.

[0019] 3 is a detailed view of part B shown in FIG. 2, and is a cross-sectional view of a duct structure of a comparative example of a railway vehicle that connects an air conditioning ventilation system to the car body. Duct 1 is a flow path that connects air conditioning ventilation system 10 to interior space 11 of the car, and is composed of surrounding metal sheet 2, sound-absorbing material 3, and perforated plate 4. As shown as exhaust (recirculated) air flow 65 in FIG. 1, air flows from interior space 11 to air conditioning ventilation system 10 through inside opening 2a that connects to the inside of the car and outside opening 2b that connects to air conditioning ventilation system 10, but noise generated by air conditioning ventilation system 10 propagates to interior space 11 of the car via duct 1.

[0020] The sound-absorbing material 3 is covered with a perforated plate 4 to prevent it from moving due to wind pressure when the air conditioning ventilation system is in operation, and the perforated plate 4 is fixed to the metal plate 2 with rivets or the like. Also, while metal plates are used as an example of the components that make up the duct 1 here, the components that make up the duct of this embodiment are not limited to this, and the duct may be made of, for example, a component in which the sound-absorbing material is covered with a flexible thin film material.

[0021] Air conditioning and ventilation system 10 is composed of fan 20, fan housing (casing) 21, transmission shaft 22, electric motor 23, cable 24, mount 25, and air conditioning and ventilation system housing 26. Fan 20 is connected to electric motor 23 via transmission shaft 22, and electric motor 23 and fan housing 21 are each fastened to mount 25 with bolts or the like. Electric motor 23 is connected to air conditioning control device (including power supply) 50 and vehicle control device 51 via cable 24, and operates upon receiving power and control signals for electric motor 23 from air conditioning control device (including power supply) 50 and vehicle control device 51.

[0022] [Embodiment 1] Fig. 4 is a cross-sectional view showing the duct structure of a railway vehicle connecting an air conditioning ventilation system and the car body, according to the first embodiment of the present invention. Note that from Fig. 4 onwards, explanations of the configuration common to Fig. 3 will be omitted. While the comparative example shown in Fig. 3 is made up of sound-absorbing material 3 and a perforated plate 4, the first embodiment differs from the comparative example in that the duct 1 is made up of a triangular prism-shaped air layer 30 formed between the top wall and side wall of the duct 1, and a finely perforated plate 31 that covers the air layer 30.

[0023] One end of the perforated plate 4 in the y direction is connected to the interior opening 2a, and the other end in the y direction is connected to the finely perforated plate 31. The lower end of the finely perforated plate 31 in the z direction is connected to the exterior opening 2b. The finely perforated plate 31 has numerous fine holes and is positioned opposite the exterior opening 2b. The finely perforated plate 31 is inclined so as to approach the interior opening 2a, which is shifted inward in the y direction relative to the exterior opening 2b, as it moves away from the air conditioning ventilation system 10 (approaching inward in the y direction as it moves upward in the z direction along the axial direction of the exterior opening 2b). This configuration can reduce low-frequency noise that cannot be fully reduced by the sound-absorbing material 3 of the comparative example. The finely perforated plate 31 may be disposed parallel to the upper wall (airtight floor 200) of the duct 1, with an air layer sandwiched between them, facing the exterior opening 2b. Hereinafter, the noise reduction structure formed by the air layer 30, the finely perforated plate 31, and the sheet metal 2 will be referred to as the finely perforated plate sound absorber 32. The finely perforated sound absorbing plate 32 is placed in the duct 1 outside the flow path of air heading from the vehicle interior toward the air conditioning ventilation system 10, and is excited to vibrate at a predetermined frequency corresponding to the sound emitted by the air conditioning ventilation system 10, as described below.

[0024] The noise reduction mechanism by the micro-perforated sound absorber 32 will now be described. The micro-perforated sound absorber 32 is composed of a micro-perforated plate 31 and an air layer 30 on its back side, and is installed so that the micro-perforated plate 31 is exposed in the space where sound absorption is desired. An air flow 65 from inside the vehicle toward the air conditioning ventilation system 10 travels from the vehicle-interior opening 2a along the exposed surface (the surface opposite the air layer 30) of the perforated plate 4 and the micro-perforated plate 31 toward the vehicle-exterior opening 2b. When sound waves from the air conditioning ventilation system 10 reach the micro-perforated plate 31 of the micro-perforated sound absorber 32, the air mass occupying the micro-pores in the micro-perforated sound absorber 32 is pushed toward the air layer 30 behind, which increases the pressure in the air layer 30 behind and pushes back the air mass occupying the micro-pores in the micro-perforated sound absorber 32.

[0025] This series of phenomena can be approximated by a one-degree-of-freedom vibration system, where for each micropore in the micro-perforated sound absorber 32, m is the mass of the air mass occupying the micropore, k is the spring constant of the air layer behind it, and c is the viscous friction coefficient due to friction between the micropore and the air mass. In this vibration system, strong vibration at a certain frequency (natural frequency) increases the friction between the micro-perforated sound absorber and the air mass, thereby attenuating the energy of sound waves arriving at this frequency, i.e., absorbing the sound. The sound absorption characteristics (sound absorption frequency) of the micro-perforated sound absorber 32 are determined by the thickness, opening diameter, and open area ratio of the micro-perforated plate, and the thickness dimension D of the air layer 30 behind the micro-perforated sound absorber (the distance from each micropore to the inner wall of the duct 1).

[0026] Due to the noise reduction mechanism of the micro-perforated sound absorbing plate 32, the frequency band in which the noise reduction effect can be obtained is limited. When the fan 20 of the air conditioning ventilation system 10 is operated at a constant rotation speed, the micro-perforated sound absorbing plate 32 can be configured to match the specific frequency caused by the fan 20, and the specific frequency can be effectively reduced.

[0027] However, the fan 20 of the air conditioning ventilation system 10 is selected arbitrarily depending on the train's speed, heat load conditions, etc. For this reason, it may be difficult to effectively reduce the noise generated by the fan 20 simply by installing a finely perforated sound absorbing plate 32 that can reduce noise of a single frequency.

[0028] 4, in this embodiment, by configuring a plurality of finely perforated plate sound absorbers 32 with different air layer thickness dimensions D at the bend portion of the duct 1 (the intersection of the top wall and the side wall), it is possible to vary the distance from each fine hole in the finely perforated plate 31 to the inner wall of the duct 1, thereby reducing noise with a plurality of peak frequencies that cannot be fully reduced by the sound absorbing material 3 of the comparative example. The interior opening 2a is shifted inward in the y direction relative to the exterior opening 2b, but the air that enters from the interior opening 2a is guided smoothly along the inclined finely perforated plate 31 to the exterior opening 2b.

[0029] Furthermore, the method of reducing noise is not limited to using a finely perforated sound absorbing plate, but a side branch type silencer may also be used as long as sufficient space corresponding to the back air layer can be secured.

[0030] [Embodiment 2] As in the first embodiment described above, passive noise control measures are possible that achieve noise reduction in multiple frequency bands in response to noise that changes from moment to moment, but active noise control measures are also possible that change the frequencies at which noise is reduced in response to noise that changes from moment to moment.

[0031] Therefore, in the second embodiment, an active noise reduction measure against air conditioning ventilation noise will be described. FIG. 5 is a cross-sectional view showing a duct structure of a railway vehicle connecting an air conditioning ventilation system and a car body, according to the second embodiment of the present invention. Instead of the finely perforated sound absorber 32 in the structure shown in FIG. 4, this embodiment differs from the configuration shown in FIG. 4 in that a vibration speaker 60 serving as a noise reduction structure is installed inside a sound-absorbing material 3 disposed on the non-flow-side surface of the perforated plate 4 (the surface facing the fan 20) and is in contact with the perforated plate 4. The vibration speaker 60 is disposed in the duct 1 outside the flow path of air flowing from the interior of the car toward the air conditioning ventilation system 10, and is excited at a predetermined frequency corresponding to the sound emitted by the air conditioning ventilation system 10. In this embodiment, a speaker is configured in the duct 1 using the perforated plate 4 as a vibration surface, and the vibration speaker 60 is connected to and controlled by the air conditioning control device 50. Other configurations are the same as those in the first embodiment.

[0032] The noise reduction mechanism of the second embodiment will be described with reference to the flowchart shown in FIG. 6. First, in step S10, when the vehicle is energized (the main power switch is turned on), the air conditioning control device 50 starts controlling the vibration speaker 60. After the vehicle is energized, the vehicle control device 51 transmits the detected vehicle speed (km / h) to the air conditioning control device (including power supply) 50 as shown in step S20. The air conditioning control device (including power supply) 50 instructs the electric motor 23 to operate at an operating frequency (b Hz) corresponding to the vehicle speed as shown in step S30. The operating frequency refers to the rotation frequency of the electric motor 23 (fan 20). The time at which this occurs is defined as time (t1).

[0033] Furthermore, as shown in step S40, the air conditioning control device (including power supply) 50 calculates the frequency to be silenced from the operating frequency (b Hz) of the electric motor 23 and the number of blades (Z) of the fan 20 at time (t3). Next, as shown in step S50, the operating frequency (b Hz) instructed to the electric motor 23 in step S30 is again instructed at time (t3). Furthermore, as shown in step S60, the air conditioning control device (including power supply) 50 vibrates the vibration speaker 60 at a frequency (b×Z Hz) based on time (t3) so that the sound (b×Z Hz) emitted by the vibration speaker 60 has a phase difference of 90° with respect to the sound to be silenced. In this way, a sound having an opposite phase to the air conditioning ventilation noise is generated, canceling out the air conditioning ventilation noise and reducing the noise.

[0034] This step S60 makes it possible to omit the installation of a microphone for feedback control that measures the sound to be silenced and confirms that a 90° phase difference has occurred with respect to the sound to be silenced, thereby reducing the cost of the noise silencing system.

[0035] Next, the process proceeds to step S70, where if the operation of the railway vehicle 100 is to be continued, the process returns to step S20, and if not, the control of the vibration speaker 60 is ended.

[0036] In railway vehicles, there is a response delay of several seconds between when air conditioning control device (including power supply) 50 outputs an operating frequency command to electric motor 23 and when the operating frequency of electric motor 23 actually reaches the command value. Therefore, if a sound of opposite phase to the air conditioning ventilation noise is generated before the operating frequency of electric motor 23 reaches the command value, there is a concern that the air conditioning ventilation noise may be amplified rather than canceled out.

[0037] For this reason, in this embodiment, in steps S50 and S60, the operation of the vibration speaker 60 is controlled after the operating frequency of the electric motor 23 reaches a steady state (time t3), but if the response delay time is sufficiently short, the operation of the vibration speaker 60 may be controlled based on time (t1) in step S30. The reference time for controlling the operation may also be determined taking into consideration the response delay of the vibration speaker 60 and slippage of the transmission shaft 22. Alternatively, the operating frequency may be set to a variable bt (determined in advance by testing or simulation) depending on time, and the vibration speaker 60 may be vibrated while changing the frequency of (bt × Z) Hz with a phase of 90° until the operating frequency of the electric motor 23 reaches a steady state.

[0038] In this embodiment, the frequency of the air conditioning ventilation noise is predicted based on the operating frequency (b Hz) of the electric motor 23 and the number of blades (Z) of the fan 20. However, the total pressure (P T kg / m 2 ), air volume (Q m 3 / min), specific noise level (L S The frequency and volume of the sound generated by the vibration speaker 60 may be controlled by adding a parameter (L dB) and predicting the noise level (L dB) of the air conditioning ventilation noise based on the added parameter.

[0039] [Embodiment 3] 7 shows the third embodiment. The third embodiment differs from the second embodiment in that it includes an air conditioning control device (including a power supply) 50, a vehicle control device 51, a cable 24, and a vibration speaker 60, and additionally includes a microphone 62. By installing the microphone 62 in a position that does not narrow the cross-sectional area of ​​the flow path of the duct 1 (for example, inside the sound-absorbing material 3 near the airtight floor 200), the sound propagating through the duct 1 is measured, and the vibration speaker 60 is controlled to emit a sound that is delayed in phase by 90° relative to the sound propagating through the duct 1 (the noise to be silenced).

[0040] The microphone 62 is used to measure the noise after the air conditioning ventilation noise has been cancelled out by the sound generated by operating the vibration speaker 60, and the noise reduction effect can be verified by comparing the result with the predicted noise level of the air conditioning ventilation noise described above. If the verification shows that the actual measured value is greater than the predicted value, this can be fed back to the operation control of the vibration speaker 60, and for example, the phase of the sound generated by the vibration speaker 60 can be further delayed until the actual measured value becomes smaller than the predicted value.

[0041] With the configuration of embodiment 3, the microphone 62 can replace the functions of steps S50 and S60 in FIG. 6, and sound that is more accurately delayed in phase by 90° relative to the noise to be silenced can be emitted from the vibration speaker 60.

[0042] Furthermore, in the above embodiment, a vibration speaker 60 is used as a device that generates a sound that is in the opposite phase to the air conditioning ventilation system noise, but the device that generates the sound is not limited to this and may be, for example, an acoustic speaker.

[0043] In the above-described second and third embodiments, the vibration speaker 60 is mounted on the perforated plate 4, but in the structures of these second and third embodiments, there is a concern that vibrations generated by the operation of the vibration speaker 60 may propagate to unintended components, causing these components to vibrate and generate noise. As a structure that solves the above-mentioned concern, as shown in Fig. 8, which is an enlarged view of range C in Fig. 5, the vibration speaker 60 can be mounted on a metal plate 2, and this metal plate 2 can be attached to the perforated plate 4 via vibration-damping material 70, thereby constituting part of the duct 1.

[0044] More specifically, a portion of the perforated plate 4 facing the vehicle exterior opening 2b is cut out and replaced with a pair of metal plates 2, which are connected to the remaining perforated plate 4 via vibration-damping material 70, and a vibration speaker 60 is attached to the outer surface (upper surface) of the upper metal plate 2. The metal plates 2 can be used as the vibration surface of the vibration speaker 60. A sound-absorbing material 3 may be placed between the pair of metal plates 2 that form part of the duct 1, or an air layer may be interposed. With this structure, vibrations generated by the vibration speaker 60 are propagated only to the metal plates 2 without being propagated to surrounding members, making it possible to generate sound only at the intended location.

[0045] [Embodiment 4] In the above-described second and third embodiments, the vibration speaker 60 is installed in only one location. However, there is a concern that the output of the sound generated by the vibration speaker 60 may not be sufficient to reduce the air conditioning ventilation noise. There is also a concern that the frequency of the sound generated by the vibration speaker 60 may be limited. To address the above-mentioned concerns, as shown in FIG. 9 , a structure may be considered in which, for a duct 1 extending in a direction perpendicular to the paper surface, multiple vibration speakers 60 are installed on a metal plate 2 constituting the duct 1 along the longitudinal direction (x direction) of the duct 1. The vibration speaker 60 is installed on the outer surface of the metal plate 2 constituting the duct 1 so as not to narrow the existing flow path cross-sectional area, and the entire metal plate 2 is used as a vibrating surface. The vibration speaker 60 is arranged in the duct 1 outside the flow path of air flowing from the vehicle interior toward the air conditioning ventilation system 10, and is excited at a predetermined frequency corresponding to the sound generated by the air conditioning ventilation system 10. By using this type of structure, the above concerns can be resolved by repeatedly applying sounds of opposite phase to the air conditioning ventilation noise and by generating sounds of different frequencies for each vibration speaker 60 without affecting the flow rate of air passing through the duct 1.

[0046] 9, and may be installed in other positions if there is space. However, it is preferable to install it as close as possible to the source of the air conditioning ventilation noise, as this reduces the range over which the sound propagates in the space and reduces the number of locations where the vibration speaker 60 needs to be installed.

[0047] To reduce air conditioning ventilation noise, at least two of the above-mentioned embodiments 1 to 4 may be combined. Additionally, sound absorbing material may be applied to the edge of the air intake port to reduce noise transmitted from the air conditioning ventilation system.

[0048] Furthermore, in the above second to fourth embodiments, the air conditioning control device (including the power supply) 50 is used to control the vibration speaker 60, but a microcomputer for controlling the vibration speaker 60 may be separately installed to control its operation.

[0049] This specification includes the disclosure of the following inventions. (First aspect) A railway vehicle having a car body, an air conditioning / ventilation device provided in the car body, a duct connecting the car body and the air conditioning / ventilation device, and a noise reduction structure, the noise reduction structure is disposed in the duct outside a flow path of air flowing from the vehicle interior toward the air conditioning ventilation system, and is excited to vibrate at a predetermined frequency corresponding to a sound emitted by the air conditioning ventilation system. A rail vehicle characterized by:

[0050] (Second aspect) In the rail vehicle of the first aspect, The noise reduction structure includes a finely perforated plate disposed in the duct and an air layer formed between the finely perforated plate and an inner wall of the duct. A rail vehicle characterized by:

[0051] (Third aspect) In the rail vehicle of the second aspect, the duct has a rectangular cross section perpendicular to the longitudinal direction of the vehicle body, the finely perforated plate is disposed at a distance from an intersection of the inner wall of the duct and is inclined with respect to an axis of the vehicle exterior opening of the duct; The distance from each micro-hole of the micro-perforated plate to the inner wall of the duct is different. A rail vehicle characterized by:

[0052] (Fourth aspect) In the railway vehicle according to any one of the first to third aspects, the noise reduction structure has a speaker that is in contact with a perforated plate disposed in the duct and is installed between the perforated plate and an inner wall of the duct, and the speaker vibrates at the predetermined frequency; A rail vehicle characterized by:

[0053] (Fifth aspect) In the railway vehicle according to any one of the first to third aspects, The noise reduction structure has a speaker installed on an outer surface of a metal plate that constitutes a part of the duct, the speaker vibrating at the predetermined frequency, and the metal plate being used as a vibration surface. A rail vehicle characterized by:

[0054] (Sixth aspect) In the rail vehicle of the fourth aspect or the fifth aspect, The predetermined frequency is determined based on the rotation speed and the number of blades of an air conditioning fan provided in the air conditioning ventilation device. A rail vehicle characterized by:

[0055] (Seventh aspect) In the rail vehicle of the sixth aspect, a microphone is installed in the duct, and vibration of the speaker is feedback-controlled based on the sound measured by the microphone; A rail vehicle characterized by:

[0056] (Eighth aspect) In the rail vehicle of the fifth aspect, The pair of metal plates are connected to a perforated plate attached inside the duct via vibration-isolating materials, and the speakers are installed on outer surfaces of the pair of metal plates. A rail vehicle characterized by: [Explanation of symbols]

[0057] 1...duct, 2...sheet metal, 3...sound-absorbing material, 4...perforated plate, 10...air conditioning ventilation unit, 11...interior space of vehicle, 20...fan, 21...fan housing, 22...transmission shaft, 23...electric motor, 24...cable, 25...mounting, 26...air conditioning ventilation unit housing, 30...air layer, 31...micro-perforated plate, 32...micro-perforated plate sound-absorbing body, 50...air conditioning control unit (including power supply), 51...vehicle control unit, 60...vibration speaker, 62...microphone, 65...flow of exhaust (recirculated) air, 70...vibration-damping material, 100...railroad vehicle, 110...car body, 111...underframe, 112...side structure, 113...roof structure, 114...end structure, 120...bogie, 130...track, 200...airtight floor, 201...upper floor, 202...floor support

Claims

1. A railway vehicle having a car body, an air conditioning / ventilation device provided in the car body, a duct connecting the car body and the air conditioning / ventilation device, and a noise reduction structure, the noise reduction structure is disposed in the duct outside a flow path of air flowing from the vehicle interior toward the air conditioning ventilation system, and is excited to vibrate at a predetermined frequency corresponding to a sound emitted by the air conditioning ventilation system. A rail vehicle characterized by:

2. The railway vehicle according to claim 1, The noise reduction structure includes a finely perforated plate disposed in the duct and an air layer formed between the finely perforated plate and an inner wall of the duct. A rail vehicle characterized by:

3. The railway vehicle according to claim 2, the duct has a rectangular cross section perpendicular to the longitudinal direction of the vehicle body, the finely perforated plate is disposed at a distance from an intersection of the inner wall of the duct and is inclined with respect to an axis of the vehicle exterior opening of the duct; The distance from each micro-hole of the micro-perforated plate to the inner wall of the duct is different. A rail vehicle characterized by:

4. The railway vehicle according to claim 1, the noise reduction structure has a speaker that is in contact with a perforated plate disposed in the duct and is installed between the perforated plate and an inner wall of the duct, and the speaker vibrates at the predetermined frequency; A rail vehicle characterized by:

5. The railway vehicle according to claim 1, The noise reduction structure has a speaker installed on an outer surface of a metal plate that constitutes a part of the duct, the speaker vibrating at the predetermined frequency, and the metal plate being used as a vibration surface. A rail vehicle characterized by:

6. The railway vehicle according to claim 4 or 5, The predetermined frequency is determined based on the rotation speed and the number of blades of an air conditioning fan provided in the air conditioning ventilation device. A rail vehicle characterized by:

7. 7. The railway vehicle according to claim 6, a microphone is installed in the duct, and vibration of the speaker is feedback-controlled based on the sound measured by the microphone; A rail vehicle characterized by:

8. The railway vehicle according to claim 5, The pair of metal plates are connected to a perforated plate attached inside the duct via vibration-isolating materials, and the speakers are installed on outer surfaces of the pair of metal plates. A rail vehicle characterized by:

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