Railway vehicles

Abstract

To provide a railroad vehicle capable of facilitating inflow of travel wind into a cooling fin arranged in a concave part at a lower part of a main body of the railroad vehicle.SOLUTION: A railroad vehicle 10 includes: a main body 11 of the railroad vehicle; a power conversion part 13 mounted on the main body 11 of the railroad vehicle; a protruding concave part 15 provided on a lower part of the main body 11 of the railroad vehicle; and a plurality of plate-like cooling fins 16 arranged in the concave part 15 to cool the power conversion part 13 with travel wind of the main body 11 of the railroad vehicle. The railroad vehicle 10 further includes a protrusion part 17 provided on a surface 152a of the concave part 15 and on an upstream side of the travel wind of the cooling fins 16, and protruding downward.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a railway vehicle, and more particularly to a railway vehicle provided with cooling fins for cooling a power conversion unit by traveling wind.

Background Art

[0002] Conventionally, a railway vehicle provided with cooling fins for cooling a power conversion unit by traveling wind is known (see, for example, Patent Document 1).

[0003] In the railway vehicle described in Patent Document 1 above, a power conversion device (power conversion unit) is installed at the bottom of the vehicle. The power conversion device includes a housing and a power conversion device main body provided inside the housing. The power conversion device also includes a cooling unit for cooling the power conversion device main body. The cooling unit has cooling fins provided so as to be exposed outside the housing. Further, on the bottom of the railway vehicle, a concave portion that protrudes upward and on which the cooling fins are arranged is provided.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the railway vehicle described in Patent Document 1, the cooling fins are arranged in a concave portion that is convex upwards. In this case, it is thought that the airflow between the ground and the railway vehicle is abruptly widened by the concave portion, making it difficult for the running air to enter the concave portion, and instead causing it to flow below the concave portion. In this case, a difference in wind speed occurs between the inside and outside (ground side) of the concave portion, resulting in the formation of an air vortex in the concave portion where the central axis extends along the direction of the sleepers, causing air stagnation (retention). When a vortex is formed in the concave portion, it prevents the running air from flowing into the cooling fins. Therefore, there is a need for a railway vehicle that can easily allow running air to flow into the cooling fins located in the concave portion at the bottom of the railway vehicle body.

[0006] This invention was made to solve the above-mentioned problems, and one of its objectives is to provide a railway vehicle that can easily allow running air to flow into cooling fins arranged in a concave portion at the bottom of the railway vehicle body. [Means for solving the problem]

[0007] To achieve the above objective, a railway vehicle according to the first aspect of this invention comprises: a railway vehicle body; a power conversion unit mounted on the railway vehicle body; an upwardly convex concave portion provided at the lower part of the railway vehicle body; a plurality of plate-shaped cooling fins extending along the direction of travel of the railway vehicle body and spaced apart in the direction of the sleepers, which cool the power conversion unit with the airflow of the railway vehicle body; and a projection that protrudes downward, provided on the surface near the concave portion, upstream of the airflow relative to the cooling fins, and overlapping with the cooling fins when viewed from the direction of travel. The projection has a shape that generates a swirling flow downstream of the projection. Note that "near the concave part" includes both the concave part itself and the area surrounding it.

[0008] This invention 1In railway vehicles with this type of curved surface, as described above, a projection is provided on the surface near the concave section and upstream of the airflow of the cooling fins, projecting downwards. This allows the direction of the airflow to be changed by the projection, thereby creating turbulence in the airflow. As a result, the turbulence in the airflow reduces the amount of air vortices that cause stagnation (retention) of air in the concave section. This suppresses the obstruction of airflow from flowing into the cooling fins caused by air vortices in the concave section. Consequently, it becomes easier to allow airflow to flow into the cooling fins located in the concave section at the bottom of the railway vehicle body.

[0009] Furthermore, by allowing airflow to easily enter the cooling fins, the cooling efficiency of the power conversion section by the cooling fins can be improved.

[0010] Also , protrusion but The projection has a shape that generates a swirling flow downstream of it. By By generating a swirling flow in the concave section, the air within the concave section is agitated by the swirling flow, effectively reducing the air vortices that form in the concave section. As a result, it becomes easier to direct airflow onto the cooling fins.

[0011] In this case, preferably, the projection has a pair of side surfaces and a bottom surface, extends along the direction of travel, and tapers toward the downstream direction of the airflow. With this configuration, the tapering shape of the projection makes it easier for the airflow flowing along the pair of side surfaces to intersect with each other at the leading edges of the pair of side surfaces, thus easily generating a swirling flow.

[0014] the above To achieve the objective, a railway vehicle according to the second aspect of this invention comprises a railway vehicle body, a power conversion unit mounted on the railway vehicle body, an upwardly convex concave portion provided at the lower part of the railway vehicle body, a plurality of plate-shaped cooling fins extending in the direction of travel of the railway vehicle body and spaced apart in the direction of the sleepers, for cooling the power conversion unit with the airflow of the railway vehicle body, and a projection provided on the surface near the concave portion, upstream of the airflow relative to the cooling fins, and overlapping with the cooling fins when viewed from the direction of travel, and projecting downward, wherein the concave portion includes a flat portion provided in the center on which the cooling fins are arranged, and a pair of inclined surfaces provided adjacent to both the upstream and downstream sides of the flat portion in relation to the airflow, and the projection is provided on both sides of the concave portion in the direction of travel relative to the cooling fins, near the pair of inclined surfaces, and near the end of the inclined surface opposite to the flat portion. If you configure it in this way, Because the protrusions are provided on both sides of the concave section in the direction of travel relative to the cooling fins, the protrusions can be positioned upstream of the cooling fins regardless of the direction of travel of the railway vehicle body. Furthermore, the concave section includes a flat section in the center where the cooling fins are positioned, and a pair of inclined surfaces adjacent to both the upstream and downstream sides of the flat section in the airflow direction. Because the protrusions are provided near the pair of inclined surfaces, they can disrupt the airflow in the vicinity of the pair of inclined surfaces. Note that "near the inclined surfaces" includes both the inclined surfaces themselves and the areas surrounding them.The protrusions near the ends of the inclined surface can disrupt the airflow. Furthermore, the area near the ends of the inclined surface is where the shape of the railway vehicle body changes, making it prone to changes in airflow. Therefore, by placing protrusions at this easily changing end, the airflow can be more effectively altered. As a result, the airflow can be more effectively disrupted. Note that "near the ends of the inclined surface" includes both the end of the inclined surface itself and the area near the end of the inclined surface.

[0015] In a railway vehicle in which the concave portion includes a flat portion and a pair of inclined surfaces, preferably, the projection is provided on the surface of the inclined surface and extends in the direction of travel, Wind while driving The shape has an increasing height as it moves downstream. With this configuration, the downstream portion of the protrusion is positioned close to the lower side of the concave section, making it easy to disrupt the airflow of the vehicle as it travels below the concave section.

[0016] In this case, preferably, the projection includes a pair of side surfaces provided on the surface of the inclined surface and gradually approaching each other downstream of the airflow, and a flat lower surface provided to connect the pair of side surfaces and extending in a direction along the horizontal. With this configuration, a swirling flow can be generated more easily by both the speed difference between the airflow flowing along the lower surface and the airflow flowing along the pair of side surfaces, and the angle difference between the airflow flowing along one of the pair of side surfaces, the airflow flowing along the other of the pair of side surfaces, and the airflow flowing along the lower surface.

[0017] In a railway vehicle having a projection that generates a swirling flow, preferably, the projection has a curved shape without sharp corners. With this configuration, stress is less likely to concentrate on the curved shape compared to sharp corners, thus suppressing localized stress concentration at the projection.

[0018] In this case, preferably, the projection has a hemispherical shape. With this configuration, the entire projection has a curved shape, which further suppresses localized stress concentration at the projection.

[0019] In a railway vehicle having a curved projection, preferably, the curved projection is integrally formed with the surface near the concave portion by press working. With this configuration, localized stress concentration at the projection is suppressed, thereby preventing the projection from breaking due to stress when the surface and projection are integrally formed. Furthermore, since the surface and projection are integrally formed, the projection is less likely to detach from the surface. In addition, the number of parts in the railway vehicle can be reduced compared to when the projection is provided separately from the surface.

[0020] The above 1 or second In a railway vehicle with a curved surface, preferably, multiple protrusions are arranged in a row along the direction of the sleepers in a region adjacent to the region where the cooling fins are provided. With this configuration, it is possible to suppress unevenness in the amount of running air flowing into the cooling fins in the direction of the sleepers, compared to the case where only one protrusion is provided. Furthermore, in order to achieve the above objective, the first of this invention 3 The railway vehicle in this configuration comprises a railway vehicle body, a power conversion unit mounted on the railway vehicle body, an upwardly convex concave portion provided at the bottom of the railway vehicle body, a plurality of plate-shaped cooling fins in the concave portion that extend along the direction of travel of the railway vehicle body and are spaced apart in the direction of the sleepers, and that cool the power conversion unit with the airflow generated by the railway vehicle body, and a projection that protrudes downward from the surface near the concave portion and is provided on the upstream side of the airflow relative to the cooling fins, wherein the projection has a shape that generates a swirling flow on the downstream side of the airflow relative to the projection and on the upstream side of the airflow relative to the cooling fins. [Effects of the Invention]

[0021] According to the present invention, as described above, it is possible to make the running wind flow easily into the cooling fins disposed in the concave portion at the lower part of the railway vehicle body.

Brief Description of the Drawings

[0022] [Figure 1] It is a schematic side view showing a railway vehicle according to the first embodiment. [Figure 2] It is an enlarged view of the vicinity of the concave portion in FIG. 1. [Figure 3] It is a perspective view of the concave portion according to the first embodiment. [Figure 4] It is a partially enlarged view of the vicinity of the protrusion in FIG. 3. [Figure 5] It is a plan view of the protrusion according to the first embodiment as viewed from below. [Figure 6] It is a plan view of the concave portion according to the first embodiment as viewed from below. [Figure 7] FIG. 7(a) is an example of a simulation result showing the flow (streamlines) of the running wind in a state where the protrusion is not disposed in the concave portion (comparative example). FIG. 7(b) is an example of a simulation result showing the flow (streamlines) of the running wind in a state where the protrusion is disposed in the concave portion (first embodiment). [Figure 8] It is an example of a simulation result comparing the wind speed of the running wind at the inlet of the cooling fins in a state where the protrusion is not disposed in the concave portion (comparative example) with the wind speed of the running wind at the inlet of the cooling fins in a state where the protrusion is disposed in the concave portion (first embodiment). [Figure 9] It is an example of a simulation result comparing the wind speed of the running wind at the center of the cooling fins in a state where the protrusion is not disposed in the concave portion (comparative example) with the wind speed of the running wind at the center of the cooling fins in a state where the protrusion is disposed in the concave portion (first embodiment). [Figure 10] It is an enlarged view of the vicinity of the concave portion according to the second embodiment. [Figure 11] It is a perspective view of the concave portion according to the second embodiment. [Figure 12] It is an enlarged view of the vicinity of the protrusion in FIG. 10. [Figure 13] This is an example of simulation results comparing the airflow velocity at the cooling fin inlet in a comparative example, the first embodiment, and the second embodiment. [Figure 14] This is an example of simulation results comparing the airflow velocity at the center of the cooling fins in a comparative example, the first embodiment, and the second embodiment. [Figure 15] Figure 13 shows an example of simulation results illustrating the variation in the Y-direction position of the airflow velocity in each of the comparative example, the first embodiment, and the second embodiment. [Modes for carrying out the invention]

[0023] The following describes embodiments of the present invention based on the drawings.

[0024] [First Embodiment] [Railway Vehicle Configuration] The configuration of the railway vehicle 10 according to the first embodiment will be described with reference to Figures 1 to 6.

[0025] Railway vehicle 10 is a railway vehicle that operates as a train consisting of multiple vehicles. As shown in Figure 1, railway vehicle 10 is configured to run on electricity supplied from an overhead line 1 as either an AC power source or a DC power source. For example, railway vehicle 10 can be a conventional line electric train or a high-speed rail vehicle. In the following explanation, railway vehicle 10 will be described using a high-speed rail vehicle as an AC electric vehicle as an example.

[0026] As shown in Figure 1, the railway vehicle 10 comprises a railway vehicle body 11, a pantograph 12, a power conversion unit 13, and electrical equipment 14 such as an induction motor and air conditioning equipment.

[0027] The power conversion unit 13 is mounted on the railway vehicle body 11. The power conversion unit 13 is located at the bottom 11a of the railway vehicle body 11.

[0028] The pantograph 12 is responsible for receiving power from the overhead wire 1. The power conversion unit 13 is responsible for converting the AC voltage from the pantograph 12, which has been transformed by a transformer (not shown), into a desired three-phase AC voltage and frequency, and outputting it to electrical equipment 14, etc.

[0029] Furthermore, the railway vehicle 10 is provided with an upwardly convex concave portion 15 located at the bottom of the railway vehicle body 11. The railway vehicle 10 is also provided with a plurality of plate-shaped cooling fins 16 arranged in the concave portion 15. Each of the plurality of cooling fins 16 is provided to protrude from the bottom of the railway vehicle 10 to the outside (atmospheric side) of the railway vehicle body 11.

[0030] The cooling fins 16 cool the power conversion unit 13 using the airflow from the railway vehicle body 11 as it travels. Specifically, the cooling fins 16 are provided so as to protrude downward (towards Z2) from the cooling plate 16a (see Figure 2) on which the power conversion unit 13 (a semiconductor element, etc., not shown) is located. In addition, multiple cooling fins 16 extend along the direction of travel of the railway vehicle body 11 (X direction) and are arranged at intervals in the direction of the sleepers (Y direction) (see Figure 6).

[0031] As shown in Figure 2, the concave portion 15 includes a flat portion 151 on which the cooling fins 16 are arranged. The flat portion 151 is located in the center of the concave portion 15 in the X direction. The concave portion 15 also includes a pair of inclined surfaces 152 located adjacent to both the upstream and downstream sides of the airflow of the flat portion 151.

[0032] In this first embodiment, the railway vehicle 10 is provided with a projection 17 that protrudes downward from the surface near the concave portion 15 and on the upstream side of the airflow of the cooling fins 16. Specifically, the projection 17 is provided on the surface 152a of the concave portion 15, which will be described later. The projection 17 is integrally formed with the railway vehicle body 11 (bottom portion 11a). The projection 17 is made of metal.

[0033] Furthermore, in the first embodiment, the projection 17 is provided on the inclined surface 152. The surface 152a on which the projection 17 is located is a surface provided on the inclined surface 152. In addition, the projection 17 is provided so as not to form a gap between it and the inclined surface 152.

[0034] Furthermore, in the first embodiment, the projections 17 are provided on both sides of the concave portion 15 in the direction of travel relative to the cooling fin 16. Specifically, the projections 17 are provided on each surface 152a of the pair of inclined surfaces 152. The structure and arrangement position of the projections 17 provided on each of the pair of inclined surfaces 152 are identical to those of the other.

[0035] In detail, the projection 17 is provided near the end 152b of the inclined surface 152 opposite to the flat surface 151. Specifically, the projection 17 is positioned on the inclined surface 152 such that the end 17a of the projection 17 opposite to the flat surface 151 is provided at the end 152b of the inclined surface 152. Although the end 152b of the inclined surface 152 is shown as angular in Figure 2, the end 152b of the inclined surface 152 may have an R-shape.

[0036] Furthermore, in the first embodiment, the projection 17 extends in the direction of travel and has a shape in which its height h increases as it moves downstream in the direction of travel. Specifically, the height h is 0 at the end 17a of the projection 17 and gradually increases as it moves downstream.

[0037] Furthermore, as shown in Figure 3, the projection 17 has a pair of side surfaces 17b and a bottom surface 17c, and extends along the direction of travel while tapering toward the downstream side of the airflow (towards the center of the concave portion 15). Specifically, the bottom surface 17c has an isosceles triangular shape when viewed from below (viewed from the Z2 direction), with the tip 17d of the projection 17 on the downstream side of the airflow as its vertex. Also, when viewed from the side, the projection 17 has a right-angled triangular shape that tapers toward the upstream side of the airflow.

[0038] In detail, the pair of side surfaces 17b of the projection 17 are provided on the surface 152a of the inclined surface 152. The pair of side surfaces 17b are provided so as to intersect the surface 152a. The pair of side surfaces 17b are provided so as to gradually approach each other downstream of the airflow. The lower surface 17c of the projection 17 is provided so as to connect the pair of side surfaces 17b. The lower surface 17c is a flat surface extending in a direction along the horizontal (a surface extending parallel to the ground).

[0039] Specifically, each of the pair of side surfaces 17b of the projection 17 is provided to extend downward (towards the Z2 direction) from the surface 152a of the inclined surface 152. That is, each of the pair of side surfaces 17b is provided to be perpendicular to the lower surface 17c of the projection 17 which extends in the horizontal direction. In the Y direction, the position where the tip 17d of the projection 17 is provided and the region S1 (see Figure 3), which will be described later, where the cooling fins 16 are arranged are spaced apart from each other.

[0040] Furthermore, in the first embodiment, as shown in Figure 3, the projections 17 are arranged in a row (six in the first embodiment) along the sleeper direction in a region S2 adjacent to the region S1 where the cooling fins 16 are provided. Specifically, in a view from below (viewed from the Z2 direction), the region S1 where the cooling fins 16 are provided is arranged to be aligned with the region S2 where the projections 17 are provided along the X direction. The multiple projections 17 are arranged in a row in region S2 with space between them. Note that the same number of projections 17 are provided in both the region S2 on the X1 side and the region S2 on the X2 side.

[0041] Furthermore, the railway vehicle 10 is provided with a bottom surface portion 18 that is adjacent to (continuous with) the concave portion 15 in the X direction. The projection portion 17 is provided so that its lower surface 17c does not protrude downward (towards the Z2 direction) relative to the bottom surface portion 18 of the railway vehicle 10. Specifically, the lower surface 17c of the projection portion 17 is provided to be flush with the bottom surface portion 18 of the railway vehicle 10. The lower end portion 16b of the cooling fin 16 (see Figure 2) is provided above (towards the Z1 direction) the bottom surface portion 18 of the railway vehicle 10.

[0042] Furthermore, as shown in Figures 4 and 5, the projection 17 has a shape that generates a swirling flow F1 downstream of the projection 17. Specifically, the running air f1 flowing along one of the pair of side surfaces 17b, the running air f2 flowing along the other of the pair of side surfaces 17b, and the running air f3 flowing along the lower surface 17c intersect with each other downstream of the projection 17 (towards the tip 17d) (see Figure 5), thereby forming the swirling flow F1. The swirling flow F1 is a swirling flow whose axis of rotation extends along the X direction.

[0043] (Simulation results) Next, referring to Figure 7, a comparison of the airflow in the concave portion 15 will be described between the case where the projection 17 is not provided (see Figure 7(a), comparative example) and the case where the projection 17 is provided (see Figure 7(b), first embodiment). In Figures 7(a) and 7(b), the airflow lines are indicated by dashed and shaded lines, respectively.

[0044] In the comparative example shown in Figure 7(a), the airflow separation occurs due to the rapid expansion of the airflow path between the ground (not shown) and the railway vehicle body 11 by the concave portion 15. As a result, it was confirmed that a vortex V caused by the stagnation (retention) of air in the concave portion 15 is formed with its axis of rotation extending along the direction of the sleepers (Y direction).

[0045] In the example shown in Figure 7(b), it was confirmed that a swirling flow F1 is formed when the projection 17 is provided in the concave portion 15. In this case as well, while vortices V are formed in the concave portion 15, it was confirmed that the region in which vortices V are formed in the first embodiment is smaller than the region in which vortices V are formed in the comparative example. This is thought to be because the swirling flow F1 agitates the air in the concave portion 15, reducing stagnation of the air in the concave portion 15.

[0046] Next, referring to Figures 8 and 9, a comparison of wind speeds will be described between the case where the projection 17 is not provided (comparative example) and the case where the projection 17 is provided (first embodiment). Note that if H is the length of the cooling fin 16 in the Z direction, then "top" in Figures 8 and 9 means a position 0.75H from the end 16b of the cooling fin 16 (see Figure 2). Also, "middle" in Figures 8 and 9 means a position 0.5H from the end 16b of the cooling fin 16. "Bottom" in Figures 8 and 9 means a position 0.25H from the end 16b of the cooling fin 16. Furthermore, the wind speed in Figures 8 and 9 refers to the average value of the wind speed at each position in the direction of the sleepers.

[0047] The simulation results shown in Figure 8 are for the inlet of the cooling fin 16 (position P1 in Figure 2). As shown in Figure 8, in all three cases, "top," "middle," and "bottom," the wind speed of the running air in the first embodiment was greater than the wind speed of the running air in the comparative example. Furthermore, as can be seen in Figure 8, the effect of the first embodiment compared to the comparative example was confirmed to be more pronounced in the order of "top," "middle," and "bottom." In particular, in the "top" and "middle" cases, the wind speed of the running air in the first embodiment was confirmed to be more than twice the wind speed of the running air in the comparative example.

[0048] Furthermore, the simulation results shown in Figure 9 are for the center of the cooling fin 16 (position P2 in Figure 2). As shown in Figure 9, in all three cases—"top," "middle," and "bottom"—the wind speed of the running air in the first embodiment was greater than the wind speed of the running air in the comparative example. Also, as can be seen in Figure 9, the effect of the first embodiment compared to the comparative example was confirmed to be more pronounced in the order of "top," "middle," and "bottom." In particular, in the "top" case, the wind speed of the running air in the first embodiment was confirmed to be about twice that of the running air in the comparative example.

[0049] From the simulation results in Figures 7 to 9 above, it was confirmed that when the protrusion 17 is provided in the concave portion 15, the airflow during driving is effectively directed into the cooling fin 16.

[0050] (Effects of the first embodiment) In the first embodiment, the following effects can be obtained.

[0051] In the first embodiment, as described above, the railway vehicle 10 is configured to have a projection 17 that protrudes downward from the surface 152a near the concave portion 15 and is located upstream of the airflow of the cooling fins 16. This allows the direction of the airflow to be changed by the projection 17, thereby causing turbulence in the airflow. As a result, the turbulence in the airflow reduces the amount of air vortices V that cause stagnation (retention) of air in the concave portion 15. This suppresses the obstruction of airflow from flowing into the cooling fins 16 caused by air vortices V in the concave portion 15. As a result, it becomes easier to allow airflow to flow into the cooling fins 16 located in the concave portion 15 at the bottom of the railway vehicle body 11.

[0052] Furthermore, by making it easier for airflow to flow into the cooling fins 16, the cooling efficiency of the cooling fins 16 can be improved.

[0053] Furthermore, in the first embodiment, the railway vehicle 10 is configured such that the projection 17 has a shape that generates a swirling flow F1 downstream of the projection 17, as described above. As a result, by generating a swirling flow F1 in the concave portion 15, the air inside the concave portion 15 is stirred by the swirling flow F1, so that the air vortex V generated in the concave portion 15 can be effectively reduced. As a result, it becomes easier to allow running air to flow into the cooling fins 16.

[0054] Furthermore, in the first embodiment, the railway vehicle 10 is configured such that the projection 17 has a pair of side surfaces 17b and a lower surface 17c, extends along the direction of travel, and tapers toward the downstream direction of the airflow. As a result, the tapering shape of the projection 17 makes it easier for the airflow flowing along the pair of side surfaces 17b of the projection 17 to intersect with each other at the leading edges of the pair of side surfaces 17b, thus easily generating a swirling flow F1.

[0055] Furthermore, in the first embodiment, the railway vehicle 10 is configured such that the projections 17 are provided on both sides of the concave portion 15 in the direction of travel relative to the cooling fins 16, as described above. This allows the projections 17 to be positioned upstream of the cooling fins 16 regardless of the direction of travel of the railway vehicle body 11.

[0056] Furthermore, in the first embodiment, the railway vehicle 10 is configured such that the projection 17 is provided near the pair of inclined surfaces 152, as described above. This allows the projection 17 to disrupt the airflow during travel near the pair of inclined surfaces 152.

[0057] Furthermore, in the first embodiment, the railway vehicle 10 is configured such that the projection 17 is provided near the end 152b of the inclined surface 152 opposite to the flat surface 151. This allows the projection 17 to disturb the airflow near the end 152b of the inclined surface 152. Also, since the area near the end 152b of the inclined surface 152 is where the shape of the railway vehicle body 11 changes, the airflow is prone to change. By positioning the projection 17 at the end 152b, where the airflow is prone to change, the airflow can be altered more effectively. As a result, the airflow can be disturbed more effectively.

[0058] Furthermore, in the first embodiment, as described above, the railway vehicle 10 is configured such that the projection 17 is provided on the surface 152a of the inclined surface 152, extends in the direction of travel, and has a shape in which the height h increases as it goes downstream in the direction of travel. As a result, the downstream portion of the projection 17 is positioned close to the lower side of the concave portion 15, so that the airflow of the train passing below the concave portion 15 can be easily disturbed.

[0059] Furthermore, in the first embodiment, the railway vehicle 10 is configured such that the projection 17 includes a pair of side surfaces 17b provided on the surface 152a of the inclined surface 152 and gradually approaching each other toward the downstream of the running airflow, and a flat lower surface 17c provided to connect the pair of side surfaces 17b and extending in a direction along the horizontal direction. This makes it easier to generate a swirling flow F1 due to both the speed difference between the slow running airflow f3 flowing along the lower surface 17c and the fast running airflow (f1, f2) flowing along the pair of side surfaces 17b, and the angular difference between the running airflow f1 flowing along one of the pair of side surfaces 17b, the running airflow f2 flowing along the other of the pair of side surfaces 17b, and the running airflow f3 flowing along the lower surface 17c.

[0060] Furthermore, in the first embodiment, the railway vehicle 10 is configured such that, as described above, multiple projections 17 are arranged in a row along the sleeper direction in a region S2 adjacent to the region S1 where the cooling fins 16 are provided. This makes it possible to suppress unevenness in the amount of running air flowing into the cooling fins 16 in the sleeper direction, compared to the case where only one projection 17 is provided.

[0061] [Second Embodiment] A second embodiment will be described with reference to Figures 10 to 15. Unlike the first embodiment, in which a projection 17 including a pair of side surfaces 17b and a bottom surface 17c is provided, this second embodiment is provided with a curved projection 117. Components similar to those in the first embodiment are shown in the figures with the same reference numerals, and their descriptions are omitted.

[0062] [Railway Vehicle Configuration] Referring to Figures 10 to 12, the configuration of the railway vehicle 110 according to the second embodiment will be described.

[0063] As shown in Figure 10, the railway vehicle 110 includes a railway vehicle body 111. The railway vehicle 110 also includes a projection 117. The projection 117 is provided on the railway vehicle body 111. Specifically, the projection 117 is positioned on the inclined surface portion 152 of the railway vehicle body 111. The end 117a of the projection 117 opposite to the flat portion 151 is provided on the end 152b of the inclined surface portion 152.

[0064] In the second embodiment, as shown in Figure 11, the projection 117 has a curved shape without sharp corners. Specifically, the surface of the projection 117 is curved overall and does not include any flat or angular portions.

[0065] In detail, the projection 117 includes a hemispherical shape. Note that the term "hemispherical shape" does not only refer to a shape obtained by cutting half of a sphere, but also broadly includes shapes obtained by cutting other than half of a sphere (for example, two-thirds of a sphere).

[0066] Furthermore, the projection 117 has a shape that generates a swirling flow F2 downstream of the projection 117. Specifically, the airflow f11 flowing along the surface of the projection 117 intersects with each other downstream of the projection 117, thereby forming the swirling flow F2. The swirling flow F2 is a swirling flow whose axis of rotation extends along the X direction.

[0067] In the second embodiment, the curved projection 117 is integrally formed with the surface 152a of the inclined surface 152 by press working. Specifically, as shown in Figure 12, the projection 117 includes an outer peripheral edge 117b formed during the press working of the projection 117. The outer peripheral edge 117b has an R shape.

[0068] Furthermore, the lower end 117c of the projection 117 is located below (towards Z2) the bottom surface 18. In other words, the projection 117 is provided to protrude from the concave portion 15. The lower end 117c of the projection 117 is located above (towards Z1) the outfitting limit L of the railway vehicle body 11 (see Figure 10).

[0069] (Simulation results) Next, Figures 13 to 15 show the simulation results comparing wind speed in the case where no protrusion is provided (comparative example), in the case where protrusion 17 is provided (first embodiment), and in the case where protrusion 117 is provided (second embodiment).

[0070] Based on the air velocity at the inlet of the cooling fin 16 (position P1 in Figure 10) (see Figure 13) and the air velocity at the center of the cooling fin 16 (position P2 in Figure 10) (see Figure 14), it was confirmed that the effect of the projection 117 in the second embodiment is approximately equivalent to the effect of the projection 17 in the first embodiment.

[0071] Figure 15 also shows the variation in wind speed at position P1. The solid line, dashed line, and dashed line represent the results for the second embodiment, the first embodiment, and the comparative example, respectively. As shown in Figure 15, it was confirmed that the variation in wind speed at the Y-direction position was smaller in the second embodiment than in the first embodiment. Although not shown in the figure, similar results were obtained at position P2.

[0072] The other configurations of the second embodiment are the same as those of the first embodiment described above.

[0073] (Effects of the second embodiment) In the second embodiment, the following effects can be obtained.

[0074] In the second embodiment, the railway vehicle 110 is configured such that the projection 117 has a curved shape without sharp corners, as described above. As a result, since stress is less likely to concentrate on the curved shape compared to sharp corners, it is possible to suppress localized stress concentration at the projection 117.

[0075] In the second embodiment, the railway vehicle 110 is configured such that the projection 117 has a hemispherical shape, as described above. As a result, the entire projection 117 has a curved shape, which further suppresses the localized concentration of stress in the projection 117.

[0076] In the second embodiment, as described above, the railway vehicle 110 is constructed such that the curved projection 117 is integrally formed with the surface 152a near the concave portion 15 by press working. This suppresses localized stress concentration at the projection 117, thereby preventing the projection 117 from being damaged due to stress when the surface 152a and the projection 117 are integrally formed. Furthermore, since the surface 152a and the projection 117 are integrally formed, it is possible to prevent the projection 117 from detaching from the surface 152a. In addition, the number of parts of the railway vehicle 110 can be reduced compared to the case where the projection 117 is provided separately from the surface 152a.

[0077] Furthermore, the other effects of the second embodiment are the same as those of the first embodiment described above.

[0078] (modified version) It should be noted that the embodiments disclosed herein are illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims rather than by the description of the embodiments above, and further includes all modifications (exceptions) within the meaning and scope equivalent to the claims.

[0079] For example, in the first and second embodiments described above, the projection 17(117) is shown to be provided on the concave portion 15, but the present invention is not limited thereto. For example, the projection 17(117) may be provided near the end 152b of the concave portion 15 (inclined surface portion 152) and on the bottom surface portion 18 of the railway vehicle body 11(111). Alternatively, the projection 17(117) may be arranged to straddle the bottom surface portion 18 and the concave portion 15.

[0080] Furthermore, while the first and second embodiments described above show examples in which the projection 17(117) has a shape that generates a swirling flow F1(F2), the present invention is not limited thereto. The projection 17(117) does not need to have a shape that generates a swirling flow F1(F2), as long as it has a shape that disrupts the airflow during driving.

[0081] Furthermore, while the first embodiment described above shows an example having a shape that extends along the direction of travel and tapers downstream of the airflow, the present invention is not limited thereto. For example, the pair of side surfaces of the projection may have a curved shape.

[0082] Furthermore, in the first embodiment described above, the lower surface 17c is shown as a flat surface extending in a direction along the horizontal (a surface extending parallel to the ground), but the present invention is not limited to this. For example, the lower surface 17c may be a surface extending upward relative to the ground.

[0083] Furthermore, in the first embodiment described above, the lower surface 17c was shown to have an isosceles triangular shape with the tip 17d of the projection 17 downstream of the airflow as its vertex when viewed from below (viewed from the Z2 direction), but the present invention is not limited to this. For example, the lower surface 17c may have a triangular shape other than an isosceles triangle, or it may have a trapezoidal shape without a tip 17d.

[0084] Furthermore, in the first embodiment described above, an example was shown in which each of the pair of side surfaces 17b is provided perpendicular to the lower surface 17c of the projection 17 extending in the horizontal direction, but the present invention is not limited thereto. For example, the angle between each of the pair of side surfaces 17b and the lower surface 17c of the projection 17 extending in the horizontal direction may be acute or obtuse.

[0085] Furthermore, while the first and second embodiments described above show examples in which the projection 17(117) is provided so as not to form a gap between it and the inclined surface 152, the present invention is not limited thereto. A railway vehicle may be provided with a projection that is provided so as to form a gap between it and the inclined surface 152.

[0086] Furthermore, while the first and second embodiments described above show examples in which the projections 17(117) are provided on both sides in the direction of travel relative to the cooling fins 16, the present invention is not limited thereto. The projections 17(117) may be provided on only one side in the direction of travel relative to the cooling fins 16.

[0087] Furthermore, while the first and second embodiments described above show examples in which the projection 17(117) is provided near the end 152b of the pair of inclined surface portions 152, the present invention is not limited thereto. For example, the projection 17(117) may be provided so as to extend from the end 152b to the vicinity of the cooling fin 16.

[0088] Furthermore, although the above embodiment shows an example in which the projection 17 has a shape in which its height h increases as it moves downstream in the direction of travel, the present invention is not limited to this. For example, the height of the projection may decrease as it moves downstream, or it may be the same size at any position in the direction of travel.

[0089] Furthermore, while the first and second embodiments described above show examples in which multiple projections 17(117) are arranged in a row along the sleeper direction in a region S2 adjacent to the region S1 where the cooling fins 16 are provided, the present invention is not limited to this. Only one projection 17(117) may be arranged in region S2.

[0090] Furthermore, while the first and second embodiments described above show examples where the railway vehicle 10 is a conventional electric train or a high-speed rail vehicle, the present invention is not limited to these. For example, the railway vehicle may be a diesel railcar (a train equipped with an engine).

[0091] Furthermore, although the first and second embodiments described above show examples in which a pair of inclined surfaces 152 are provided in the concave portion 15, the present invention is not limited thereto. The concave portion does not necessarily have to have inclined surfaces.

[0092] Furthermore, although the second embodiment described above shows an example in which the projection 117 has a hemispherical shape, the present invention is not limited thereto. The projection may have a curved shape without sharp corners, other than a hemispherical shape (for example, a semi-ellipsoidal shape).

[0093] Furthermore, while the first and second embodiments described above show examples in which a plurality of protrusions 17(117) are arranged in a single line along the direction of the sleeper, the present invention is not limited to this. The plurality of protrusions 17(117) may be arranged in a zigzag (staggered) pattern along the direction of the sleeper.

[0094] Furthermore, although the first and second embodiments described above show examples in which the projection 17(117) is integrally formed with the railway vehicle body 11(111) (inclined surface portion 152), the present invention is not limited thereto. The projection 17(117) may be formed separately from the railway vehicle body 11(111). That is, the projection 17(117) may be fastened to the railway vehicle body 11(111) (inclined surface portion 152) by fastening members or the like. [Explanation of symbols]

[0095] 10, 110 Railway vehicles 11, 111 Railway vehicle body 13 Power Conversion Unit 15 Concave part 16 cooling fins 17, 117 Protrusion 17b Side 17c Bottom side 151 Flat area 152 Slope section 152a Surface (Surface of concave portion, surface of inclined portion) 152b End F1, F2 swirl flow h height S1 region (region where cooling fins are provided) S2 region (the region where the protrusions are located)

Claims

1. A railway vehicle body, The power conversion unit mounted on the aforementioned railway vehicle body, A convex concave portion is provided on the lower part of the railway vehicle body, The concave portion is provided with a plurality of plate-shaped cooling fins that extend along the direction of travel of the railway vehicle body and are spaced apart in the direction of the sleepers, and that cool the power conversion unit with the airflow from the railway vehicle body as it travels. The surface near the concave portion, and located upstream of the airflow relative to the cooling fins, and overlapping with the cooling fins when viewed from the direction of travel, comprises a projection that protrudes downward, A railway vehicle wherein the projection has a shape that generates a swirling flow downstream of the projection.

2. The railway vehicle according to claim 1, wherein the projection has a pair of side surfaces and a bottom surface, extends along the direction of travel, and tapers toward the downstream direction of the airflow.

3. A railway vehicle body, The power conversion unit mounted on the aforementioned railway vehicle body, A convex concave portion is provided on the lower part of the railway vehicle body, The concave portion is provided with a plurality of plate-shaped cooling fins that extend along the direction of travel of the railway vehicle body and are spaced apart in the direction of the sleepers, and that cool the power conversion unit with the airflow from the railway vehicle body as it travels. The surface near the concave portion, and located upstream of the airflow relative to the cooling fins, and overlapping with the cooling fins when viewed from the direction of travel, comprises a projection that protrudes downward, The concave portion includes a flat portion located in the center on which the cooling fins are arranged, and a pair of inclined surfaces arranged adjacent to both the upstream and downstream sides of the airflow over the flat portion. A railway vehicle wherein the protrusions are provided on both sides of the concave portion in the direction of travel relative to the cooling fin, near the pair of inclined surfaces, and near the end of the inclined surface opposite to the flat portion.

4. The railway vehicle according to claim 3, wherein the projection is provided on the surface of the inclined surface, extends in the direction of travel, and has a shape in which its height increases as it moves downstream of the airflow.

5. The railway vehicle according to claim 4, wherein the projection includes a pair of side surfaces provided on the surface of the inclined surface and gradually approaching each other toward the downstream direction of the running airflow, and a flat lower surface provided to connect the pair of side surfaces and extending in a direction along the horizontal direction.

6. The railway vehicle according to claim 1, wherein the projection has a curved shape without sharp corners.

7. The railway vehicle according to claim 6, wherein the projection has a hemispherical shape.

8. The railway vehicle according to claim 6 or 7, wherein the curved projection is integrally formed with the surface near the concave portion by press working.

9. The railway vehicle according to any one of claims 1 to 8, wherein the protrusions are arranged in a plurality along the direction of the sleepers in a region adjacent to the region where the cooling fins are provided.

10. The railway vehicle itself, The power conversion unit mounted on the aforementioned railway vehicle body, A convex concave portion is provided on the lower part of the railway vehicle body, The concave portion is provided with a plurality of plate-shaped cooling fins that extend along the direction of travel of the railway vehicle body and are spaced apart in the direction of the sleepers, and that cool the power conversion unit with the airflow from the railway vehicle body as it travels. The surface near the aforementioned concave portion and provided on the upstream side of the airflow relative to the cooling fins, comprises a projection that protrudes downward, A railway vehicle wherein the projection has a shape that generates a swirling flow downstream of the airflow relative to the projection and upstream of the airflow relative to the cooling fins.

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