Pressure fluctuation reduction structure

Abstract

A pressure fluctuation reduction structure is provided that reduces at least low-frequency pressure fluctuations occurring in a bogie storage space. [Solution] A pressure fluctuation reduction structure that reduces at least low-frequency pressure fluctuations that occur in a storage space provided at the bottom of a railway vehicle body for storing bogies, the pressure fluctuation reduction structure having one or more plate-shaped members provided within the storage space, at least one of the plate-shaped members being attached to a side wall of the bottom that constitutes the storage space, the side wall being on the rear side in the direction of travel of the railway vehicle, and extending from the side wall into a rear space near the rear end of the bogie.

Description

[Technical Field]

[0001] The present invention relates to a pressure fluctuation reduction structure that reduces pressure fluctuations that occur in a storage space provided at the bottom of a railway vehicle body for storing bogies. [Background technology]

[0002] It is known that low-frequency pressure fluctuations in the 10 to 100 Hz range occur when railway vehicles move, and these pressure fluctuations are aerodynamically generated by the airflow around the train. Of these pressure fluctuations, components above 20 Hz can be a source of audible noise. Furthermore, components between 5 and 20 Hz can cause vibrations in fixtures and fittings in houses along railway tracks. It is known that these low-frequency pressure fluctuations are difficult to attenuate with existing soundproofing walls installed along the tracks.

[0003] One location where low-frequency pressure fluctuations occur is the storage space provided at the bottom of the body of a railway vehicle for storing bogies. Various structures have been proposed as means for reducing pressure fluctuations, and for example, structures for reducing pressure fluctuations in railway vehicles are known, as described in Patent Documents 1 to 5.

[0004] Patent Document 1 discloses a railway vehicle that is equipped with a bogie enclosure having a bottom cover that covers the bottom of the bogie in the cavity of the bogie, and that reduces aerodynamic noise by reducing the amount of airflow entering the cavity. The bottom cover covers the entire cavity in the bottom of the bogie, and is provided with wheel wells and air holes for passing cooling air.

[0005] Patent Document 2 discloses a reduction structure that can reduce low-frequency pressure fluctuations that occur in a bogie storage space. This reduction structure is made up of curved surfaces formed at both ends of the bogie storage space along the traveling direction in a cross section along the traveling direction of the vehicle, and the curved surfaces are formed continuously from the top to the bottom of the bogie storage space and smoothly continue to the bottom of the vehicle.

[0006] Patent Document 3 discloses a railway vehicle equipped with noise reduction means at the downstream inner corner of a bogie storage space formed at the bottom of the vehicle for storing bogies. The noise reduction means weakens the strength of vortices released at the upstream end of the bogie storage space. It also mitigates the impact of the vortex colliding with the downstream end of the bogie storage space. This reduces aerodynamic noise.

[0007] Patent Document 4 discloses a railway vehicle that is equipped with a low-noise member attached to the bogie via an arm, which deflects the airflow hitting the bogie downward, preventing fast airflow from hitting the bogie and reducing aerodynamic noise. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-229492 [Patent Document 2] Japanese Patent Application Publication No. 2018-122730 [Patent Document 3] Japanese Patent Publication No. 2020-117035 [Patent Document 4] Japanese Patent Publication No. 2022-065742 Summary of the Invention [Problem to be solved by the invention]

[0009] However, with regard to the cover that completely covers the cavity on the bottom of the bogie, as disclosed in Patent Document 1, there is room for improvement in terms of the materials, processing, and installation costs of the cover components, as well as the maintainability of the bogie. Furthermore, the adoption of a curved surface, such as the noise reduction structure disclosed in Patent Document 2, may be subject to limitations, such as a reduced space required to accommodate underfloor equipment. Furthermore, when noise reduction means are provided in the cavity, as in Patent Document 3, structural limitations exist in order to ensure the maintainability of the bogie, etc. Furthermore, with regard to the low-noise member disclosed in Patent Document 4, if the airflow striking the bogie is deflected downward, the airflow affects the ground flow velocity below the containment space. A change in ground flow velocity increases the airflow velocity striking ground equipment on the track, such as ballast, which can cause the ballast to scatter.

[0010] The present invention has been made in view of the above circumstances, and has an object to provide a pressure fluctuation reduction structure that reduces at least low-frequency pressure fluctuations that occur in a bogie storage space. [Means for solving the problem]

[0011] In order to achieve the above-mentioned object, one embodiment of the present invention provides a pressure fluctuation reduction structure that reduces at least low-frequency pressure fluctuations that occur in a storage space provided at the bottom of a railway vehicle body for storing bogies, and has one or more plate-shaped members provided within the storage space, at least one of which is attached to a side wall of the bottom that constitutes the storage space, the side wall being rearward in the direction of travel of the railway vehicle, and extending from the side wall into a rear space near the rear end of the bogie.

[0012] The plate-like member may be attached to the side wall at a height position equal to or higher than the height of an axle of the bogie, with the height of the axle being used as a reference position.

[0013] Furthermore, one embodiment of the present invention is a pressure fluctuation reduction structure that reduces at least low-frequency pressure fluctuations that occur in a storage space provided at the bottom of a railway vehicle body for storing bogies, and has one or more plate-like members provided within the storage space, at least one of which is attached to a side wall of the bottom that constitutes the storage space, at least at a corner between the side wall on the rear side in the direction of travel of the railway vehicle and the upper wall of the bottom, and extends from the corner into a rear space near the rear end of the bogie.

[0014] Furthermore, one embodiment of the present invention is a pressure fluctuation reduction structure that reduces at least low-frequency pressure fluctuations that occur in a storage space provided at the bottom of a railway vehicle body for storing bogies, and has one or more plate-like members provided within the storage space, with at least one of the plate-like members attached to an upper wall of the bottom that constitutes the storage space, at least on the rear side in the direction of travel of the railway vehicle, and extending from the upper wall into a rear space near the rear end of the bogie.

[0015] The plate-like member may have one or more recesses, which may be arranged to correspond to components included in the bogie that protrude into the rear space so as to prevent interference between the components and the plate-like member.

[0016] The plate-like members may be provided in multiple locations in the width direction of the railway vehicle, and the multiple plate-like members may be spaced apart to correspond to components included in the bogie that protrude into the rear space so that the components do not interfere with the plate-like members.

[0017] One of the multiple plate-shaped members may have an extension length that is shorter than the other plate-shaped members, and the short extension length of the plate-shaped member may be spaced apart to correspond to a component included in the bogie that protrudes into the rear space so that the component does not interfere with the plate-shaped member. [Effects of the Invention]

[0018] According to the present invention, it is possible to reduce pressure fluctuations that occur in a storage space provided at the bottom of the body of a railway vehicle for storing bogies. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a side view showing an outline of an example configuration of a railway vehicle equipped with a pressure fluctuation reducing structure. [Figure 2] 1 showing an outline of a configuration example of a pressure fluctuation reducing structure according to a first embodiment. [Figure 3] 1 showing an outline of a configuration example of a pressure fluctuation reducing structure according to a first embodiment.

[0023] FIG. [Figure 4] 1 is a plan view showing an outline of a configuration example of a plate-shaped member according to a first embodiment. [Figure 5] FIG. 4 is a plan view showing an outline of a modified example of the plate-shaped member according to the first embodiment. [Figure 6] FIG. 10 is a plan view showing an outline of another modified example of the plate-shaped member according to the first embodiment. [Figure 7] FIG. 4 is an explanatory view showing an example of the function of the plate-shaped member according to the first embodiment. [Figure 8] 1 showing an outline of a configuration example of a pressure fluctuation reducing structure according to a second embodiment. [Figure 9] 1 showing an outline of a configuration example of a pressure fluctuation reducing structure according to a third embodiment. [Figure 10] FIG. 1 shows the results of confirmation test 1. [Figure 11] FIG. 1 shows the results of confirmation test 1. [Figure 12] FIG. 10 is a diagram showing the results of confirmation test 2. [Figure 13] FIG. 10 is a diagram showing the results of confirmation test 2. [Figure 14] FIG. 10 shows the results of confirmation test 3. [Figure 15] FIG. 10 shows the results of confirmation test 3. [Figure 16] FIG. 10 shows the results of confirmation test 4. [Figure 17] FIG. 10 shows the results of confirmation test 4. [Figure 18] FIG. 10 shows the results of confirmation test 5. [Figure 19] FIG. 10 is an explanatory diagram showing an example of airflow in a storage space of a conventional railway vehicle while the vehicle is running. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In this specification and the drawings, elements having substantially the same functional configuration are designated by the same reference numerals, and redundant description will be omitted. Regarding the coordinate axes designated in the drawings, the X-axis indicates the vehicle length direction (rail direction), the Y-axis indicates the vehicle width direction (sleeper direction), and the Z-axis indicates the vehicle height direction. In this specification, the positive X-axis side may be referred to as the "front," the negative X-axis side as the "rear," the positive Y-axis side as the "right," the negative Y-axis side as the "left," the positive Z-axis side as the "upper," and the negative Z-axis side as the "lower."

[0021] <Railway vehicles> (First embodiment) Fig. 1 is a side view showing an outline of an example configuration of a railway vehicle equipped with a pressure fluctuation reducing structure. Fig. 2 is a partially enlarged view of Fig. 1. Fig. 3 is a partially enlarged view of the railway vehicle of Fig. 1, showing a plan view looking upward from the underside of the railway vehicle (positive direction of the Z axis in the figure).

[0022] 1, railway vehicle 1 is, for example, a high-speed railway vehicle such as a Shinkansen train ("Shinkansen" is a registered trademark) that runs at high speed on rails (not shown). Railway vehicle 1 includes bogie 10 and a car body 20.

[0023] As shown in FIGS. 2 and 3 , the bogie 10 has a pair of wheel sets 11. The pair of wheel sets 11 are spaced apart from each other and arranged substantially parallel to each other in the longitudinal direction of the railway vehicle 1. As shown in FIG. 3 , each wheel set 11 has an axle 12 and a pair of wheels 13. The axle 12 is formed in a columnar shape, and the pair of wheels 13 are arranged so as to be spaced apart from each other in the axial direction of the axle 12, i.e., the width direction of the railway vehicle 1. Each wheel 13 runs while rotating on a rail (not shown). The bogie 10 also has a bogie frame 14. The bogie frame 14 is provided with the wheel sets 11 as well as a desired configuration for driving the bogie 10. For example, a motor box 16, a gear box 17, and the like are attached to the bogie frame 14. The motor box 16 has a motor and provides power to the bogie 10. The gear box 17 transmits the power of the motor to the wheel sets 11.

[0024] As shown in Figures 1 to 3, the car body 20 has a storage space S at its bottom for storing the bogie 10. The car body 20 also has a cover 21 at its bottom. The cover 21 covers at least the sides of the space at the bottom of the car body 20 (specifically, the space under the floor).

[0025] The cover 21 has, for example, a pair of side covers 22 and a bottom cover 23. The pair of side covers 22 are arranged opposite each other in the vehicle width direction. Each side cover 22 covers at least the space under the floor of the car body 20, other than the storage space S, so as to block it from the sides. Therefore, in the car body 20, the sides of the underfloor equipment 24 housed in the space under the floor are covered by the side covers 22. Also, in the example of FIGS. 1 and 3, the side covers 22 also cover the storage space S so as to block it from the sides. That is, in the example of the figures, the side covers 22 are formed over the entire car body 20 in the vehicle longitudinal direction. However, in FIG. 2, for the convenience of explaining the configuration example of the bogie 10, the side covers 22 on the sides of the storage space S are omitted from the illustration.

[0026] The bottom cover 23 covers the space under the floor of the vehicle body 20 from below, except for the storage space S. Therefore, in the vehicle body 20, the bottom cover 23 covers the lower part of the underfloor equipment 24.

[0027] The storage space S is covered at the front and rear by a front blocking plate 25 and a rear blocking plate 26. The front blocking plate 25 and the rear blocking plate 26 may be included in the cover 21. Hereinafter, these may be collectively referred to simply as "blocking plates 25, 26."

[0028] The blocking plates 25, 26 respectively constitute the front and rear side walls of the bottom of the vehicle body 20 which form the storage space S. The upper ends of the blocking plates 25, 26 are connected to an upper wall 27 of the bottom of the vehicle body 20, and the lower ends are connected to the bottom cover 23. The blocking plates 25, 26 are each provided so as to be perpendicular to the bottom cover 23. The blocking plates 25, 26 are each provided with a front plate-like member 31 and a rear plate-like member 32. Hereinafter, these may be collectively referred to simply as "plate-like members 31, 32." The blocking plates 25, 26 may be provided at an angle so that the storage space S widens from the upper end to the lower end.

[0029] <Plate-shaped components> The following describes in detail the configuration of the plate-like members 31, 32 according to this embodiment. The front plate-like member 31 is attached to the front closing plate 25, and extends from the front closing plate 25 into the front space Sa near the front end of the bogie .

[0030] The rear plate-like member 32 is attached to the rear closing plate 26 and extends from the rear closing plate 26 into the rear space Sb near the rear end of the bogie 10.

[0031] Here, the "front space Sa" according to this embodiment can be defined as a partial space in the storage space S that is forward of a plane (ZY plane, two-dot chain line shown in FIGS. 2 and 3) that is perpendicular to the vehicle length direction (X-axis direction) and includes the end 12a on the front side of the axle 12. Similarly, the "rear space Sb" can be defined as a partial space in the storage space S that is rear of a plane (ZY plane, two-dot chain line shown in FIGS. 2 and 3) that is perpendicular to the vehicle length direction (X-axis direction) and includes the end 12b on the rear side of the axle 12.

[0032] Furthermore, "extending" means that the plate-like members 31, 32 extend from their attachment positions so as to occupy at least a part of the front space Sa or the rear space Sb. Furthermore, the "extending length" refers to the length of the plate-like members 31, 32 themselves, in the extending direction.

[0033] Fig. 4 is a plan view showing an outline of an example of the configuration of the plate-shaped member 32 according to this embodiment. For convenience, Fig. 4 and Figs. 5 and 6 described below illustrate the rear plate-shaped member 32, but the same applies to the front plate-shaped member 31, with the X-axis direction in the figures reversed.

[0034] The plate-like members 31 and 32 according to this embodiment include a plurality of recesses D1 to D3. The recesses D1 to D3 correspond to components included in the bogie 10 that protrude into the front space Sa or the rear space Sb, and are provided so as to prevent interference between the components and the plate-like members 31 and 32. In one embodiment, the recesses D1 to D3 are provided so as to prevent interference between the components and the plate-like members 31 and 32 when the bogie 10 rotates.

[0035] 3 and 4, the recessed portion D1 is provided corresponding to the bogie frame 14 and an axle box (not shown) that covers the axle 12 attached to the bogie frame 14. The recessed portion D2 is provided corresponding to the wheel 13. The recessed portion D3 is provided corresponding to the gear box 17.

[0036] It should be noted that the configuration of the plate-shaped members 31 and 32 is not limited to this example. Fig. 5 is a plan view showing an outline of a modified example of the plate-shaped members 31 and 32. Fig. 6 is a plan view showing an outline of another modified example of the plate-shaped members 31 and 32.

[0037] 5, the plate-like members 31 and 32 are each provided with one recess D4. Similar to the recesses D1 to D3, the recess D4 is provided in correspondence with a component included in the bogie 10 that protrudes into the front space Sa or the rear space Sb, so as to prevent interference between the component and the plate-like members 31 and 32. The recess D4 is provided, for example, in correspondence with the bogie frame 14, an axle box (not shown) that covers the axle 12 attached to the bogie frame 14, the wheel 13, and the gearbox 17, although this is not a limitation.

[0038] In the modified example shown in FIG. 6, each of the plate-like members 31 and 32 is divided into three parts, including a first portion 33, a second portion 34, and a third portion 35. The first portion 33, the second portion 34, and the third portion 35 are spaced apart from one another in the vehicle width direction (Y-axis direction), and the space D5 is regarded as a recess. The second portion 34, which is located between the first portion 33 and the third portion 35, has a shorter extension length than the first portion 33 and the third portion 35. This shorter extension length D6 is regarded as a recess. Similar to the recesses D1 to D3, the space D5 and the short extension length D6 are provided in correspondence with components included in the bogie 10 that protrude into the front space Sa or the rear space Sb, so as to prevent interference between the components and the plate-like members 31 and 32. The separation portion D5 and the short extension length D6 are provided to correspond to, but are not limited to, the bogie frame 14, the axle box (not shown) covering the axle 12 attached to the bogie frame 14, the wheels 13, and the gearbox 17, as an example.

[0039] The technical significance of the plate-like members 31 and 32 will be described below. Fig. 19 is a diagram showing an example of airflow during travel in the storage space S of a conventional railway car 1 that does not have the plate-like members 31 and 32. Fig. 7 is a diagram showing an example of airflow during travel in the storage space S of a railway car 1 according to this embodiment that has the plate-like members 31 and 32.

[0040] As a result of extensive investigation, the inventors have found the following about the conventional railway vehicle 1. That is, as shown in FIG. 19 , when the conventional railway vehicle 1 is traveling in the positive direction of the X-axis, an airflow (A1) is generated in the negative direction of the X-axis relative to the carbody 20. A part of the airflow (A1) enters the rear space Sb of the storage space S from the rear side of the bogie 10 (A2). The airflow (A2) that has entered the storage space S goes around the bogie 10 and flows between the bogie 10 and the upper wall 27 (A3). Thereafter, the airflow (A3) travels above the bogie 10 and flows out of the storage space S from the front side of the bogie 10 (A4).

[0041] The present inventors further conducted extensive research into the airflows A1 to A4, and as a result, found that the airflows A1 to A4 may cause pressure fluctuations in the low frequency range.

[0042] In contrast, in this embodiment, as shown in Fig. 7, the rear plate member 32 suppresses (B) the airflow (A2) that attempts to enter the rear space Sb of the storage space S from the rear side of the bogie 10. Furthermore, even if part of the airflow does enter the storage space S, the rear plate member 32 suppresses (A3) the airflow (B) from flowing around the bogie 10. This allows the rear plate member 32 to reduce the flow of the airflows A1 to A4. As a result, it is possible to at least reduce pressure fluctuations in the low-frequency range caused by the airflows A1 to A4.

[0043] When the traveling direction of the railway vehicle 1 is opposite to that described above (negative direction of the X axis), the front plate-shaped member 31 reduces the flow of the airflows A1 to A4 by the same action as the rear plate-shaped member 32. As a result, it is possible to at least reduce pressure fluctuations in the low frequency range caused by the airflows A1 to A4.

[0044] From another perspective, the plate-like members 31, 32 extend in the front space Sa or the rear space Sb, and therefore do not affect the maintainability of the components provided in the storage space S, including the bogie 10. In other words, it is possible to achieve both not affecting the maintainability and reducing pressure fluctuations in the low-frequency range. From this perspective, a configuration can be adopted in which a portion of the plate-like members 31, 32 extends further from the front space Sa or the rear space Sb toward the center of the bogie 10, within a range that does not affect the maintainability.

[0045] The preferred mounting positions of the plate-like members 31, 32 relative to the blocking plates 25, 26 can be determined from the viewpoint of achieving the above-mentioned functions of the plate-like members 31, 32. The preferred mounting positions are not limited to these, but can be determined, for example, by experiment or simulation, taking into consideration the effect of reducing pressure fluctuations in the low-frequency range.

[0046] From another perspective, a preferable mounting position can be a height position above the reference position H0 (dashed line in FIG. 2) where the height (position in the Z-axis direction) of the axle 12 is the reference position H0, as shown in FIG. 2. This allows the plate-like members 31, 32 to be mounted so as not to increase high-frequency pressure fluctuations while still achieving the effect of reducing pressure fluctuations.

[0047] A more preferable mounting position can be determined, for example, through experiments or simulations, by comprehensively considering the effect of reducing pressure fluctuations in the low frequency range and the impact on high frequency pressure fluctuations. For example, (1) a position where the effect of reducing pressure fluctuations in the low frequency range is relatively high but the impact on high frequency pressure fluctuations is relatively large, (2) a position where the effect of reducing pressure fluctuations in the low frequency range is relatively low but the impact on high frequency pressure fluctuations is relatively small, or (3) a position where the effect of reducing pressure fluctuations in the low frequency range is moderate and the impact on high frequency pressure fluctuations is moderate. Note that "relatively" refers to a comparison between different mounting positions, and does not mean an absolute high or low. The mounting position can be selected from among the above positions (1) to (3) depending on the intended use of the railway vehicle 1.

[0048] From another point of view, the preferred mounting positions can be positions where the plate-like members 31 and 32 do not interfere with components (not shown) that may be provided on the blocking plates 25 and 26 .

[0049] In the above embodiment, the plate-like members 31 and 32 are attached so as to be parallel to the XY plane, but this is not limitative and they can be attached so as to be tilted at a desired angle relative to the XY plane.

[0050] (Second embodiment) The following describes in detail the configuration of the plate-shaped members 41 and 42 according to the second embodiment. This embodiment is similar to the first embodiment except for the configuration of the plate-shaped members 41 and 42, so reference is made to Fig. 1 and the above description of Fig. 1. Fig. 8 is a partially enlarged view of Fig. 1.

[0051] The front plate-shaped member 41 is attached to either the front blocking plate 25 or the upper wall 27 at the front corner 43 between the front blocking plate 25 and the upper wall 27 of the bottom of the car body 20, and extends from the front corner 43 into the forward space Sa near the front end of the bogie 10.

[0052] The rear plate-like member 42 is attached to either the rear blocking plate 26 or the upper wall 27 at a rear corner 44 between the rear blocking plate 26 and the upper wall 27 at the bottom of the car body 20, and extends from the rear corner 44 into the rear space Sb near the rear end of the bogie 10.

[0053] The rear plate member 42 according to this embodiment suppresses the airflow (A2) that attempts to enter the rear space Sb of the storage space S from the rear side of the bogie 10. It also suppresses the airflow (A2) that has entered the storage space S from flowing around the bogie 10 (A3). This at least reduces the flow of the airflows A1 to A4. As a result, it is possible to at least reduce the pressure fluctuations in the low-frequency range caused by the airflows A1 to A4.

[0054] Furthermore, when the direction of travel of the railway vehicle 1 is opposite to that described above (negative direction of the X-axis), the front plate-shaped member 41 can at least reduce the pressure fluctuations in the low frequency range caused by the airflows A1 to A4 by acting in the same manner as the rear plate-shaped member 42 described above.

[0055] A preferred mounting angle of the plate-like members 41, 42 can be determined from the viewpoint of whether the plate-like members 41, 42 exert the above-mentioned functions. The mounting angle is, for example, the angle formed between the upper wall 27 and the plate-like members 41, 42 in a side view. Although not limited to this, a preferred mounting position can be determined, for example, by experiment or simulation, taking into consideration the effect of reducing pressure fluctuations in the low-frequency range.

[0056] From another point of view, a preferable mounting angle can be set so that the plate-like members 41 and 42 do not interfere with components (not shown) that may be provided on the blocking plates 25 and 26 .

[0057] (Third embodiment) The following describes in detail the configuration of the plate-like members 51 and 52 according to the third embodiment. This embodiment is similar to the first embodiment except for the configuration of the plate-like members 51 and 52, so reference is made to Fig. 1 and the above description of Fig. 1. Fig. 9 is a partially enlarged view of Fig. 1.

[0058] The front plate member 51 is attached to the upper wall 27 and extends from the upper wall 27 into the storage space S. In the present embodiment shown in Figure 9, the front plate member 51 is attached to the upper wall 27 near the front end of the bogie 10 and extends from the upper wall 27 into the front space Sa near the front end of the bogie 10.

[0059] The rear plate member 52 is attached to the upper wall 27 and extends from the upper wall 27 into the storage space S. In the present embodiment shown in Figure 9, the rear plate member 52 is attached to the upper wall 27 near the rear end of the bogie 10 and extends from the upper wall 27 into the rear space Sb near the rear end of the bogie 10.

[0060] When the rear plate member 52 according to this embodiment is attached so as to extend in the rear space Sb as shown in FIG. 9, it at least weakens the airflow (A2) that attempts to enter the rear space Sb of the storage space S from the rear side of the bogie 10. It also prevents the airflow (A2) that has entered the storage space S from flowing around the bogie 10 (A3). When the rear plate member 52 is attached forward of the rear space Sb, it at least weakens some of the airflows A1 to A4. This at least reduces the flow of the airflows A1 to A4. As a result, it is possible to at least reduce pressure fluctuations in the low-frequency range caused by the airflows A1 to A4.

[0061] Furthermore, when the direction of travel of the railway vehicle 1 is opposite to that described above (negative direction of the X-axis), the front plate-shaped member 51 can at least reduce the pressure fluctuations in the low-frequency range caused by the airflows A1 to A4 by acting in the same manner as the rear plate-shaped member 52 described above.

[0062] <Confirmation Test 1> 10 and 11 are diagrams showing the results of confirmation test 1 conducted using a wind tunnel testing machine to examine the pressure fluctuation reduction effect achieved by providing the plate-like members 31 and 32 according to the first embodiment. In confirmation test 1, models 1, 2, and 3 that imitate 1 / 5 scale railway vehicle 1 and a comparative example model were used.

[0063] The comparative example model was configured without the plate-like members 31, 32. Models 1 to 3 were provided with the plate-like members 31, 32 according to the first embodiment, and were attached so that the height distance (length in the Z-axis direction) [mm] from the reference position H0, which is the height (position in the Z-axis direction) of the axle 12, of the blocking plates 25, 26 was as follows: (height distance from reference position H0) Model 1:25mm Model 2:50mm Model 3:75mm

[0064] Furthermore, in Models 1 to 3 and the comparative example model, no cart 10 was provided in the storage space S. Furthermore, the plate-like members 31 and 32 in Models 1 to 3 did not have any recesses and were approximately rectangular in shape in a plan view, with dimensions of a thickness of 2.5 mm and an extension length of 140 mm.

[0065] The results in Figures 10 and 11 show the sound pressure levels (after array processing) associated with pressure fluctuations in Models 1 to 3 and the comparative example model. In Figures 10 and 11, the circle (◯) plots show the results for the comparative example model, the diamond (◇) plots show the results for Model 1, the triangle (△) plots show the results for Model 2, and the square (□) plots show the results for Model 3. Figure 10 shows the measured sound pressure levels of low-frequency pressure fluctuations generated in a wind tunnel test at a wind speed of 260 km / h, while Figure 11 shows the measured sound pressure levels of high-frequency aerodynamic noise generated in a wind tunnel test at a wind speed of 325 km / h, corrected using frequency weighting characteristic A (A-weighted sound pressure level).

[0066] As is clear from FIG. 10, in a wind tunnel test at a wind speed of 260 km / h, a reduction in the sound pressure level of pressure fluctuations of 31.5 Hz or less was observed in all of Models 1 to 3.

[0067] As is clear from Figure 11, in a wind tunnel test at a wind speed of 325 km / h, Models 2 and 3 did not produce any increase, or produced very little, in the A-weighted sound pressure level of aerodynamic noise in the high-frequency band within the frequency range shown. Model 1 produced an increase in the A-weighted sound pressure level of aerodynamic noise at some frequencies.

[0068] In addition, a test similar to Confirmation Test 1 was also conducted to confirm the sound pressure level of pressure fluctuations when only the rear plate member 32 of Model 2 was attached and the front plate member 31 was not attached. In this test, almost the same results as those for Model 2 in Figure 10 were obtained, and it was confirmed that even when only the rear plate member 32 was attached, there was an effect of reducing the sound pressure level of pressure fluctuations.

[0069] <Confirmation Test 2> 12 and 13 are diagrams showing the results of confirmation test 2, which was conducted using a wind tunnel testing machine to examine the pressure fluctuation reduction effect achieved by providing the plate-like members 31, 32 according to the first embodiment. In confirmation test 2, model 2 from confirmation test 1 and a comparative example model were used, and bogies 10 were provided in the storage spaces S of model 2 and the comparative example model.

[0070] In Model 2 and the comparative model, the distance from the end 12a on the front side of the axle 12 of the bogie 10 to the front blocking plate 25, and the distance from the end 12b on the rear side of the axle 12 to the rear blocking plate 26 were both 125 mm.

[0071] The results in Figures 12 and 13 show the sound pressure levels (after array processing) associated with pressure fluctuations in Model 2 and the comparative example model. In Figures 12 and 13, the circle (◯) plots show the results for the comparative example model, and the square (□) plots show the results for Model 2. Figure 12 shows the measurement of the sound pressure level of low-frequency pressure fluctuations generated in a wind tunnel test at a wind speed of 260 km / h, while Figure 13 shows the measurement of the sound pressure level of high-frequency aerodynamic noise generated in a wind tunnel test at a wind speed of 325 km / h, with correction applied using frequency weighting characteristic A.

[0072] As is clear from FIG. 12, in a wind tunnel test at a wind speed of 260 km / h, Model 2 showed a reduction in the sound pressure level of pressure fluctuations at 25 Hz or less compared to the comparative model.

[0073] As is clear from Figure 13, in a wind tunnel test at a wind speed of 325 km / h, Model 2 showed almost no increase in the A-weighted sound pressure level of aerodynamic sound in the high-frequency band in the frequency range shown in the figure, compared to the comparative model.

[0074] <Confirmation Test 3> 14 and 15 are diagrams showing the results of confirmation test 3, which was conducted using a wind tunnel testing machine to examine the pressure fluctuation reduction effect achieved by providing plate-like members 41 and 42 according to the second embodiment. In confirmation test 3, models 4 and 5, which imitate 1 / 5 scale railway vehicles 1, and a comparative model were used. The comparative model was configured without the plate-like members 41 and 42. Models 4 and 5 were provided with the plate-like members 41 and 42 according to the second embodiment, and were attached so that their respective attachment angles, i.e., the angles formed between the upper wall 27 and the plate-like members 41 and 42 in a side view, were as follows: (mounting angle) Model 4: 45 degrees Model 5: 25 degrees

[0075] Furthermore, in Model 4, Model 5 and the comparative model, no carriage 10 was provided in the storage space S. Furthermore, the dimensions of the plate-like members 41, 42 in Models 4 and 5 were a thickness of 2.5 mm and an extension length excluding the recessed portion of 145 mm.

[0076] The results in Figures 14 and 15 show the sound pressure levels (after array processing) associated with pressure fluctuations in Model 4, Model 5, and the comparative model. In Figures 14 and 15, the circle (◯) plots show the results for the comparative model, the triangle (△) plots show the results for Model 4, and the square (□) plots show the results for Model 5. Figure 14 shows the measurement of the sound pressure level of low-frequency pressure fluctuations generated in a wind tunnel test at a wind speed of 260 km / h, while Figure 15 shows the measurement of the sound pressure level of high-frequency aerodynamic noise generated in a wind tunnel test at a wind speed of 325 km / h, with correction applied using frequency weighting characteristic A.

[0077] As is clear from Figure 14, in a wind tunnel test at a wind speed of 260 km / h, a reduction in the sound pressure level of pressure fluctuations below 31.5 Hz was observed in both Models 4 and 5.

[0078] As is clear from Figure 15, in a wind tunnel test at a wind speed of 325 km / h, Models 4 and 5 showed little or no increase in the A-weighted sound pressure level of aerodynamic sound in the high frequency band within the frequency range shown. Model 4 had a lower A-weighted sound pressure level of aerodynamic sound in the high frequency band compared to Model 5.

[0079] In addition, by a test similar to Confirmation Test 3, the sound pressure level of pressure fluctuations was also confirmed when the bogie 10 was installed in the storage space S of the model 4. In this test, it was confirmed that the sound pressure level of pressure fluctuations was reduced even when the bogie 10 was installed.

[0080] <Confirmation Test 4> 16 and 17 are diagrams showing the results of confirmation test 4, which was conducted using a wind tunnel tester to examine the pressure fluctuation reduction effect due to the provision of plate-like members 51, 52 according to the third embodiment. In confirmation test 4, a 1 / 5-scale model 6 simulating the railway vehicle 1 and a comparative model were used. The comparative model was configured without the plate-like members 41, 42. The model 6 was provided with the plate-like members 51, 52 according to the third embodiment, and was attached so that the distance from the blocking plates 25, 26 was 245 mm.

[0081] In addition, in the model 6 and the comparative example model, no carriage 10 was provided in the storage space S. In addition, the dimensions of the plate-like members 51 and 52 in the model 6 were set to an extension length of 90 mm excluding the recessed portions.

[0082] The results in Figures 16 and 17 show the sound pressure levels (after array processing) associated with pressure fluctuations in Model 6 and the comparative example model. In Figures 16 and 17, the circle (◯) plots show the results for the comparative example model, and the square (□) plots show the results for Model 6. Figure 16 shows the measurement of the sound pressure level of low-frequency pressure fluctuations generated in a wind tunnel test at a wind speed of 260 km / h, while Figure 17 shows the measurement of the sound pressure level of high-frequency aerodynamic noise generated in a wind tunnel test at a wind speed of 325 km / h, with correction applied using frequency weighting characteristic A.

[0083] As is clear from FIG. 16, in a wind tunnel test at a wind speed of 260 km / h, Model 6 showed a reduction in the sound pressure level of pressure fluctuations at 40 Hz or less compared to the comparative model.

[0084] As is clear from Figure 17, in a wind tunnel test at a wind speed of 325 km / h, Model 6 showed almost no increase in the A-weighted sound pressure level of aerodynamic sound in the high-frequency band, except for a few frequencies, compared to the comparative model, within the frequency range shown in the figure.

[0085] <Confirmation Test 5> 18 is a diagram showing the results of confirmation test 5, which was conducted using a wind tunnel testing machine to examine the pressure fluctuation reduction effect achieved by providing plate-like members 31 and 32 according to a modified example of the first embodiment. In confirmation test 5, models 7 and 8 simulating 1 / 5 scale railway vehicle 1, model 2 of confirmation test 1 described above as a reference example, and a comparative example model were used. The comparative example model was configured without the plate-like members 31 and 32.

[0086] Plate-like members 31 and 32 according to the modified example of the first embodiment shown in Fig. 5 were attached to model 7. The dimensions of plate-like members 31 and 32 in model 7 were a thickness of 2.5 mm, an extension length of recess D4 of 53.6 mm, and an extension length of the portion excluding recess D4 of 114 mm. The attachment positions of plate-like members 31 and 32 in model 7 were the same as those in model 1.

[0087] Plate-like members 31 and 32 according to the modified example of the first embodiment shown in Fig. 6 were attached to model 8. The dimensions of plate-like members 31 and 32 in model 8 were a thickness of 2.5 mm, an extension length of first portion 33 and third portion 35 of 114 mm, and an extension length of second portion 34 of 82 mm. The attachment positions of plate-like members 31 and 32 in model 8 were the same as those in model 1.

[0088] Furthermore, in Model 2, Model 7, Model 8 and the comparative example model, the carriage 10 was not provided in the storage space S.

[0089] The results in Figure 18 show the sound pressure levels (after array processing) of pressure fluctuations in Models 2, 7, and 8 as the difference when the sound pressure level of pressure fluctuations in the comparative model is set to 0. In Figure 18, the solid line in the center of the graph shows the sound pressure level of the comparative model, the circle (◯) plots show the results for Model 2, the square (□) plots show the results for Model 7, and the triangle (△) plots show the results for Model 8. Figure 18 shows the measurement of the sound pressure levels of low-frequency pressure fluctuations that occur in a wind tunnel test at a wind speed of 260 km / h.

[0090] As is clear from Figure 18, in a wind tunnel test at a wind speed of 260 km / h, a reduction in the sound pressure level of pressure fluctuations below 100 Hz was observed in both Models 7 and 8.

[0091] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The above-described embodiments may be omitted, substituted, or modified in various ways without departing from the scope and spirit of the appended claims. For example, the components of the above-described embodiments may be arbitrarily combined. Such an arbitrary combination naturally provides the functions and effects of each of the components involved in the combination, and also provides other functions and effects that are apparent to those skilled in the art from the description of this specification.

[0092] 1, the plate-like members 31, 32, 41, 42, 51, and 52 according to the above embodiment are attached to the gap 1a between the railway cars 1, 1 so that an air current flowing relatively in the opposite direction to the traveling direction of the railway cars 1 does not enter the gap 1a between the cars. This makes it possible to reduce pressure fluctuations that may occur when the air current enters the gap 1a between the cars.

[0093] In one embodiment, the plate-like members 31, 32, 41, 42, 51, and 52 according to the above embodiment are attached to a pantograph storage section (not shown) in the railway vehicle 1 so that an air current flowing relatively in the opposite direction to the traveling direction of the railway vehicle 1 does not enter the storage section. This makes it possible to reduce pressure fluctuations that may occur when the air current enters the storage section.

[0094] Furthermore, the effects described herein are merely descriptive or exemplary and are not limiting. In other words, the technology according to the present disclosure may achieve other effects that would be apparent to a person skilled in the art from the description of this specification, in addition to or in place of the above-described effects. [Explanation of symbols]

[0095] A1, A2, A3, A4, B Airflow S Storage space Sa front space Sb rear space 1. Railway vehicles 10 carts 20 Body 11 wheel set 12 axles 13 wheels 14 Bogie frame 16 Motor box 17 Gearbox 21 Cover 22 Side cover 23 Bottom cover 24 Underfloor equipment 25 Front cover 26 Rear cover plate 31, 41, 51 Front plate-shaped member 32, 42, 52 Rear plate-shaped member

Claims

1. A pressure fluctuation reduction structure that reduces at least low-frequency pressure fluctuations that occur in a storage space provided at the bottom of a railcar body for storing bogies, one or more plate-like members provided in the storage space; At least one of the plate-like members is The storage space is provided on a side wall of the bottom portion, which is attached to the side wall on the rear side in the direction of travel of the railway vehicle, A pressure fluctuation reducing structure extends from the side wall into a rear space near the rear end of the bogie.

2. A pressure fluctuation reduction structure that reduces at least low-frequency pressure fluctuations that occur in a storage space provided at the bottom of a railcar body for storing bogies, one or more plate-like members provided in the storage space; At least one of the plate-like members is The storage space is formed on a side wall of the bottom portion, and the storage space is attached to at least a corner between the side wall on the rear side in the traveling direction of the railway vehicle and the upper wall of the bottom portion, A pressure fluctuation reducing structure extending from the corner portion into a rear space near the rear end of the bogie.

3. A pressure fluctuation reduction structure that reduces at least low-frequency pressure fluctuations that occur in a storage space provided at the bottom of a railcar body for storing bogies, one or more plate-like members provided in the storage space; At least one of the plate-like members is attached to the upper wall of the bottom portion that forms the storage space, A pressure fluctuation reducing structure extending from the top wall into the containment space.

4. The plate-shaped member has, on the side wall, The pressure fluctuation reducing structure according to claim 1 , wherein the height of the axle of the bogie is taken as a reference position, and the structure is attached at a height position equal to or higher than the reference position.

5. The plate-like member is attached to at least the rear side of the upper wall in the direction of travel of the railway vehicle, The pressure fluctuation reducing structure according to claim 3 , which extends from the upper wall into a rear space near a rear end of the bogie.

6. the plate-like member has one or more recesses, The pressure fluctuation reduction structure according to any one of claims 1 to 5, wherein the recess is provided to correspond to a component included in the bogie that protrudes into the rear space so as not to interfere with the component and the plate-like member.

7. a plurality of the plate-like members are provided in a width direction of the railway vehicle, A pressure fluctuation reduction structure as described in any one of claims 1 to 5, wherein the plurality of plate-like members correspond to components included in the bogie that protrude into the rear space, and are spaced apart so as not to interfere with the components and the plate-like members.

8. One of the plurality of plate-shaped members has an extension length shorter than the other plate-shaped members, 8. The pressure fluctuation reduction structure according to claim 7, wherein the short extension length of the plate-like member corresponds to a component included in the bogie that protrudes into the rear space, and is set so that the component does not interfere with the plate-like member.

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