Ventilated structures and railway vehicles

Abstract

To provide a new technique of a ventilation structure capable of suppressing wind noise and securing a ventilation amount during traveling when an air intake is provided on an outer surface of a railway vehicle.SOLUTION: A ventilation structure 10 includes a pair of air intakes (a first air intake 21 and a second air intake 22) provided symmetrically in an advancing direction of a side cover 5 and in its reverse direction. Each of the air intakes has an open width which is gradually increased toward an end part from a tip part, and has a shape where a ventilation cross section is gradually increased. Further, the ventilation structure 10 has negative pressure region forming structure parts (a first recessed part 31 and a second recessed part 32) forming negative pressure regions at adjacent positions corresponding to the air intakes, respectively.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a ventilation structure. [Background technology]

[0002] Electric vehicles are equipped with power conversion devices. For example, electric vehicles running on AC electrified sections, such as Shinkansen trains, are equipped with power conversion devices consisting of a converter unit that converts AC to DC and an inverter unit that converts DC to AC. Power conversion devices are equipped with semiconductor elements that require cooling. In particular, the higher the speed of a vehicle, the higher the thermal load on the semiconductor elements, resulting in higher cooling performance requirements.

[0003] Fans are generally used to cool semiconductors, but due to the demand for smaller and lighter power conversion devices, a cooling method using the wind that flows around the outside of the vehicle while it is moving (hereinafter referred to as "driving wind") is known (see, for example, Patent Document 1).

[0004] The technology in Patent Document 1 involves placing a water-cooled circulating heat dissipation unit (radiator) for cooling the power conversion device inside an underfloor duct, and cooling the heat dissipation unit by passing air through the underfloor duct through a pair of air intakes located on the outer surface of the vehicle along the direction of travel. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-271646 Summary of the Invention [Problem to be solved by the invention]

[0006] However, installing air intakes on the outer surface of a railway vehicle can generate wind noise while the vehicle is moving, which can become a source of noise. One way to reduce wind noise is to make the air intake opening smaller, but simply making the opening smaller inevitably reduces the amount of ventilation.

[0007] Furthermore, similar problems arise not only when an air intake is provided for cooling purposes but also when an air intake is provided for ventilation purposes.

[0008] The problem that the present invention aims to solve is to provide a new ventilation structure technology that achieves both suppression of wind noise while the vehicle is in motion and ensuring sufficient ventilation when an air intake is provided on the outer surface of the vehicle. [Means for solving the problem]

[0009] A first invention for solving the above-mentioned problems is a ventilation structure that has a pair of air intakes arranged symmetrically on the outer surface of a railway vehicle in the direction of travel and the opposite direction, and that guides the running wind introduced from the air intake upstream in the direction of travel into a duct and exhausts it from the air intake downstream in the direction of travel, and each of the pair of air intakes has a structure in which the opening width and ventilation cross-sectional area gradually increase from the tip of the air intake toward the other air intake, and the ventilation structure has a negative pressure area forming structure that forms a negative pressure area corresponding to each of the pair of air intakes, between the air intake and the other air intake on the outer surface, in close proximity to the air intake.

[0010] According to the first aspect of the present invention, each of the pair of air intakes has a shape in which the opening width and cross-sectional area of ​​the airflow gradually increase from the leading end of the air intake to the trailing end (the end on the other air intake side). Therefore, when the air intake is used as an intake port, wind noise generated therefrom can be suppressed. Furthermore, the negative pressure area forming structure creates a negative pressure area near the opening of the other air intake, which serves as an exhaust port, and this negative pressure area effectively induces and exhausts exhaust from the duct. Therefore, the air intake, which serves as an intake port, effectively takes in the wind generated by driving, ensuring a sufficient amount of ventilation. In other words, it is possible to ensure a sufficient amount of ventilation while suppressing wind noise.

[0011] A second aspect of the present invention is a ventilation structure in which the inclination angle of the ventilation inclined surface of each of the pair of air intakes relative to the outer surface is 15 degrees or more and 25 degrees or less.

[0012] Increasing the angle of the ventilation slope of the air intake, which serves as the intake port, increases the opening area of ​​the duct entrance connected to the air intake, making it easier to ensure sufficient ventilation. However, if the angle is too large, the possibility of boundary layer separation occurring at the ventilation slope increases, and if boundary layer separation occurs, the ventilation volume will plateau even if the duct opening area is increased. According to the second aspect of the present invention, boundary layer separation at the ventilation inclined surface can be suppressed, while the opening area of ​​the duct inlet can be increased, thereby increasing the amount of intake air.

[0013] A third invention is a ventilation structure in which the negative pressure area forming structure is a recess.

[0014] A fourth aspect of the present invention is a ventilation structure in which the recess has a first slope closer to the air intake and a second slope closer to the other air intake, and the inclination angle of the first slope is greater than the inclination angle of the second slope.

[0015] According to the third or fourth aspect of the present invention, the negative pressure area forming structure does not protrude from the outer surface, so that the air resistance and wind noise caused by the negative pressure area forming structure can be reduced while forming a negative pressure area.

[0016] A fifth invention is a ventilation structure, wherein the inclination angle of the second slope is an angle that induces boundary layer separation.

[0017] According to the fifth aspect of the present invention, the recessed portion causes boundary layer separation of the traveling wind at the end of the second slope, creating a transverse vortex that swirls in a direction intersecting the traveling wind, thereby forming a strong negative pressure region.

[0018] As a sixth aspect of the present invention, the ventilation structure may be configured such that the negative pressure area forming structure portion is a convex portion.

[0019] A seventh aspect of the present invention is a ventilation structure in which the negative pressure area forming structure is provided across the opening width at the close position.

[0020] According to the seventh aspect of the present invention, a negative pressure area can be formed across the width of the opening.

[0021] The eighth invention is a ventilation structure in which the height direction length of the negative pressure area forming structure from the outer surface is 0.5 to 0.8 times the height direction length of the lip portion of the air intake.

[0022] According to the eighth aspect of the present invention, it is possible to achieve an appropriate balance between suppressing wind noise caused by the negative pressure area forming structure and ensuring a sufficient amount of ventilation.

[0023] A ninth aspect of the present invention is a railway vehicle equipped with the ventilation structure of any one of the above-mentioned aspects of the present invention.

[0024] According to the ninth aspect of the present invention, it is possible to realize a railway vehicle that exhibits the same effects as any of the above-mentioned aspects of the present invention. [Brief explanation of the drawings]

[0025] [Figure 1] 1 is a side external view showing an example of the configuration of a high-speed railway vehicle having a ventilation structure of a first embodiment. [Figure 2] 1 is a perspective view showing a configuration example of a ventilation structure according to a first embodiment. [Figure 3] 1 is a side view of the ventilation structure of the first embodiment, with the openings of the first air intake and the second air intake facing forward. [Figure 4] IV-IV cross section of Figure 3. [Figure 5] XY cross section of the first recess and the second recess. [Figure 6] 3 is a diagram for explaining an outline of the flow of wind when traveling in the ventilation structure of the first embodiment. FIG. [Figure 7] FIG. 6 is a perspective view of a ventilation structure according to a second embodiment. [Figure 8]FIG. 10 is a side view of the ventilation structure of the second embodiment, with the openings of the first air intake and the second air intake facing forward. [Figure 9] IX-IX cross section of Figure 8. [Figure 10] FIG. 10 is an XY cross-sectional view of a first protrusion and a second protrusion of the second embodiment. [Figure 11] 10A and 10B are diagrams for explaining an outline of the flow of wind when traveling in the ventilation structure of the second embodiment. [Figure 12] 10A and 10B are XY cross-sectional views showing examples of the shapes of a first convex portion and a second convex portion in the third embodiment. [Figure 13] Graph comparing the wind speed ratio of the inflow wind speed with that of a conventional ventilation structure (conventional configuration). [Figure 14] A graph comparing the wind noise reduction effect with that of a conventional ventilation structure (conventional configuration). [Figure 15] Graph comparing the inflow wind speed depending on the protrusion shape (shape of the convex part) of the negative pressure area forming structure. [Figure 16] A graph comparing wind noise caused by different protrusion heights (height of the convex parts) of the negative pressure area forming structure. [Figure 17] FIG. 10 is a diagram of a conventional ventilation structure (conventional configuration) viewed from the front with the first and second running air intakes facing forward. [Figure 18] XVIII-XVIII cross section of Figure 17. DETAILED DESCRIPTION OF THE INVENTION

[0026] An example of an embodiment to which the present invention is applied will be described below, but it goes without saying that the form to which the present invention can be applied is not limited to the following embodiment.

[0027] FIG. 1 is a side external view showing an example of the configuration of a railway vehicle 3 of a high-speed railway having a ventilation structure 10 of this embodiment. For ease of explanation, each figure shows X, Y, and Z axes in an orthogonal right-handed system representing directions, with the positive direction of the X axis representing the direction of travel / forward of the railway vehicle 3, the positive direction of the Y axis representing the leftward direction, and the positive direction of the Z axis representing the upward direction. Note that although an intermediate car is shown as an example of the railway vehicle 3, this embodiment can also be applied to a lead car in the same way.

[0028] The railway vehicle 3 has a water-cooled circulation type radiator 7 placed under the floor as a cooling mechanism for the power conversion device (not shown), and has a ventilation structure 10 for supplying the radiator 7 with the wind generated relatively as the railway vehicle 3 moves as cooling wind.

[0029] The ventilation structure 10 has an underfloor duct 14 in which the radiator 7 is installed, a pair of air intakes (first air intake 21, second air intake 22) that open into the left side cover 5, and a pair of recesses (first recess 31, second recess 32) that correspond to each of the pair of air intakes.

[0030] When the railway vehicle 3 travels forward (in the positive direction of the X-axis), the wind generated by the travel is introduced from the first air intake 21 into the underfloor duct 14 and passes through the radiator 7. The air that has passed through the radiator 7 is exhausted from the second air intake 22. When the direction of travel of the railway vehicle 3 reverses, the wind generated by the travel is introduced from the second air intake 22 into the underfloor duct 14, passes through the radiator 7, and is exhausted from the first air intake 21.

[0031] FIG. 2 is a perspective view showing an example of the configuration of the ventilation structure 10. As shown in FIG. FIG. 3 is a side view of the ventilation structure 10, as seen with the openings of the first air intake 21 and the second air intake 22 facing forward. FIG. 4 is a cross-sectional view taken along line IV-IV in FIG.

[0032] The ventilation structure 10 has a first air intake 21 and a second air intake 22 spaced apart in the front-to-rear direction. The first air intake 21 and the second air intake 22 have shapes symmetrical in the front-to-rear direction. Here, the first air intake 21 will be described, and a description of the second air intake 22 will be omitted.

[0033] The first air intake 21 has a structure in which the width of the opening 23 (opening width; width in the Z-axis direction) gradually increases from the tip (end on the positive side of the X-axis) to the end (end on the negative side of the X-axis; end on the side of the second air intake 22), and the cross-sectional area of ​​the airflow also gradually increases. This structure is realized, for example, with reference to the shape profile of a NACA (National Advisory Committee for Aeronautics) duct. That is, when the first air intake 21 is viewed from the normal direction to the opening surface (positive direction of the Y-axis), the opening width, which is the width in the Z-axis direction, from the tip to the end forms a roughly isosceles triangle designed so that the rate of increase in the opening width, which is the width in the Z-axis direction, increases from around the center between the tip and the end, and then decreases and approaches 1 as it approaches the end.

[0034] A lip 24 having a streamlined XY cross section is provided at the end of the first air intake 21. The ventilation inclined surface 26 (which can also be called a ramp) gradually increases in depth (change in position in the negative Y-axis direction) from the tip and is connected to the underfloor duct 14 (see Figure 4).

[0035] Here, the ventilation structure 10 of this embodiment will be compared with a conventional ventilation structure 90. FIG. 17 is a side view of the conventional ventilation structure 70 corresponding to FIG. 3, and FIG. 18 is a cross-sectional view (cross-sectional view taken along XVIII-XVIII in FIG. 17) of the conventional ventilation structure 70 corresponding to FIG. 4. As shown in FIGS. 3 and 17, in the ventilation structure 10, like the conventional ventilation structure 90, the vertical width of the side cover 5 is fixed, and the opening width Aw that the first air intake 21 can take at the rear end is a specified value derived from the vertical width of the side cover 5. This specified value is the same as the opening width Aw of the first traveling wind intake 91 (corresponding to the first air intake 21) and the second traveling wind intake 92 (corresponding to the second air intake 22) in the conventional ventilation structure 90.

[0036] In this embodiment, in which the shape profile of the first air intake 21 is adapted to the shape profile of a NACA duct, the front-to-rear length (length in the X-axis direction) of the first air intake 21 can be set to, for example, 0.86 times (0.86Al) the total length Al (see Figure 17) of the first running wind intake 91 and the second running wind intake 92 of the conventional ventilation structure 90.

[0037] Similarly, when the opening height Ah (entrance gap of the underfloor duct 14) directly below the lip portion 24 of the first air intake 21 is applied to the shape profile of a NACA duct, the opening area from the side cover 5 is reduced compared to the conventional ventilation structure 90, and as a result, the intake efficiency of the first air intake 21 may be lower than that of the first running wind intake 91. Therefore, as shown in FIG. 4, in the ventilation structure 10 of this embodiment, the opening height Ah directly below the lip portion 24 of the first air intake 21 is set to be approximately the same as the opening height Ah0 of the conventional ventilation structure 90 shown in FIG.

[0038] Specifically, the ventilation inclined surface 26 of the first air intake 21 is inclined at an angle of 15 degrees or more and 25 degrees or less (more preferably 19 degrees) from the outer surface of the side cover 5, and extends to just below the lip portion 24. The ventilation inclined surface 26 is then inclined to smoothly connect with the inner surface of the underfloor duct 14. As a result, the opening height Ah at the end of the lip portion 24 of the first air intake 21 is approximately the same as the opening height Ah0 of the conventional ventilation structure 90.

[0039] The ramp angle of a typical NACA duct (corresponding to the inclination angle of the ventilation inclined surface 26) is about 5 to 7 degrees, and at most about 11 degrees. Therefore, it can be said that the first air intake 21 is not a NACA duct itself, but has a unique shape and configuration suited to the use of the ventilation structure 90 of the railway vehicle 3.

[0040] 2 to 4, the first recess 31 of the first air intake 21 is provided across the opening width of the first air intake 21 at a position close to the lip portion 24 on the outer surface of the side cover 5. Similarly, in the second air intake 22 which is symmetrical in the front-to-rear direction, the second recess 32 is provided across the opening width of the second air intake 22 at a position close to the lip portion 24 on the outer surface of the side cover 5.

[0041] FIG. 5 is an XY cross-sectional view of the first recess 31 and the second recess 32. As shown in FIG. Since the first recess 31 and the second recess 32 have a symmetrical shape in the front-rear direction, the first recess 31 will be described and a description of the second recess 32 will be omitted.

[0042] The first recess 31 has a first slope 33 closer to the corresponding first air intake 21 and a second slope 35 closer to the other air intake (second air intake 22). The depth of the first recess 31 (the length in the Y-axis direction with the outer surface of the side cover 5 as the reference plane; the length in the height direction) is the deepest position where the first slope 33 and the second slope 35 are connected, and is 0.5 to 0.8 times the height direction length Rh of the lip portion 24 (the thickness of the lip portion 24) (0.7 times in the example of Figure 5; 0.7Rh in Figure 5).

[0043] The first slope 33 is a slope that slopes downward from the outer surface of the lip portion 24 to the deepest position, and the length in the front-rear direction can be set to, for example, 0.7Rh.

[0044] The second slope 35 is a slope that slopes upward from the deepest position rearward toward the outer surface of the side cover 5, and has a gentler inclination angle than the first slope 33. The length of the second slope 35 in the front-to-rear direction can be, for example, 2.1Rh.

[0045] FIG. 6 is a diagram for explaining an outline of the flow of wind in the ventilation structure 10 during running. Of the traveling wind, the first traveling wind W1 that reaches the first air intake 21 is introduced into the first air intake 21. At this time, because the first air intake 21 has an opening structure that references the shape profile of a NACA duct, the air intake can introduce air while suppressing the generation of air resistance and wind noise more than the first traveling wind intake 91 of the conventional ventilation structure 90 (see FIG. 17).

[0046] The introduced first traveling wind W1 is used for heat exchange by passing through the radiator 7 installed in the underfloor duct 14. The first traveling wind W1 that has passed through the radiator 7 heads toward the second air intake 22.

[0047] On the other hand, of the traveling wind that was not introduced into the first air intake 21, the second traveling wind W2 that approaches the second recess 32 is smoothly guided into the recess along the second slope 35 and then bounces up along the first slope 33, causing a sudden change in flow direction. The second traveling wind W2 is bounced up, causing boundary layer separation, creating turbulence that includes vortices that are transverse to the traveling wind. This turbulence creates a negative pressure region 9 near the second air intake 22. In other words, the second recess 32 functions as a negative pressure region-forming structure.

[0048] The negative pressure area 9 exerts a suction effect that sucks air up from the underfloor duct 14 that is connected to the second air intake 22. Therefore, the first road wind W1 that passes through the radiator 7 and heads toward the second air intake 22 is exhausted more effectively than in a configuration without the second recess 32, increasing the amount of ventilation. The suction effect of the negative pressure area 9 also extends to the first air intake 21 through the underfloor duct 14, improving the air introduction efficiency (which can also be said to be intake efficiency) of the first air intake 21.

[0049] When the traveling direction of the railway vehicle 3 reverses front to back, the air flow in the ventilation structure 10 is also reversed from the front to the back in the example of FIG. 6. That is, a portion of the traveling wind is introduced from the second air intake 22, passes through the underfloor duct 14, and passes through the radiator 7. The air that has undergone heat exchange in the radiator 7 is exhausted from the first air intake 21. Meanwhile, a portion of the traveling wind that reaches the first recess 31 (wind corresponding to the second traveling wind W2 in FIG. 6) is smoothly guided into the recessed shape along the second slope 35 of the first recess 31, and then bounces up along the first slope 33, generating a negative pressure area 9 in the vicinity of the first air intake 21. In other words, when the traveling direction of the railway vehicle 3 reverses front to back, the first recess 31 functions as a negative pressure area forming structure.

[0050] Corresponding to each of the pair of air intakes, the first air intake 21 and the second air intake 22, a negative pressure area forming structure is provided between the first air intake 21 and the second air intake 22 on the outer surface by a first recess 31 formed in a position close to the first air intake 21, and a negative pressure area forming structure is provided by a second recess 32 formed in a position close to the second air intake 22.

[0051] The slope shape of the first recess 31 is not limited to this, and may be any shape that can form a negative pressure region. For example, the second slope 35 may have a gentle inclination angle sufficient to guide the flow into the recess, while the first slope 33 may have a steep inclination angle sufficient to bounce the flow in the recess and cause boundary layer separation. As a result, in the first embodiment, the inclination angle of the first slope 33 is greater than the inclination angle of the second slope 35.

[0052] Second Embodiment Next, a second embodiment to which the present invention is applied will be described. However, differences from the first embodiment will be mainly described, and components similar to those in the first embodiment will be assigned the same reference numerals as in the first embodiment and will not be described again.

[0053] FIG. 7 is a perspective see-through view showing a configuration example of a ventilation structure 10B of the second embodiment. The ventilation structure 10B has an underfloor duct 14, a pair of air intakes (first air intake 21B, second air intake 22B) that open to the side cover 5, and a pair of protrusions (first protrusion 41, second protrusion 42) that correspond to each of the pair of air intakes.

[0054] FIG. 8 is a side view of the ventilation structure 10B when the openings of the first air intake 21B and the second air intake 22B are viewed from the front. The first air intake 21B and the second air intake 22B have a structure that is smaller overall than the first air intake 21 and the second air intake 22 of the ventilation structure 10 of the first embodiment. In addition, the ventilation structure 10B has a first protrusion 41 instead of the first recess 31 of the first embodiment, and a second protrusion 42 instead of the second recess 32.

[0055] Specifically, the shape profiles of the first air intake 21B and the second air intake 22B are set with reference to the shape profile of the NACA duct, as in the first embodiment, but the opening width (the length of the opening along the Z-axis direction) is set to 0.74 times (0.74Aw) the opening width Aw of the first running wind intake 91 in the conventional ventilation structure 90 shown in Figure 17.

[0056] The front-to-rear length of the first air intake 21B and the second air intake 22B is set to 0.6 times (0.6Al) the overall length Al of the first traveling wind intake 91 and the second traveling wind intake 92 in the conventional ventilation structure 90 shown in FIG.

[0057] FIG. 9 is a cross-sectional view taken along line IX-IX in FIG. The opening height of the first air intake 21B (entrance gap of the underfloor duct 14) is set to 0.74 times (0.74Ah) the opening height Ah in the first embodiment. The inclination angle of the ventilation inclined surface 26 is set to 15 degrees or more and 25 degrees or less, similar to the first embodiment, and is more preferably 19 degrees.

[0058] 8 and 9, the first protrusion 41 is provided across the opening width of the first air intake 21B at a position close to the lip portion 24 of the first air intake 21B on the outer surface of the side cover 5. The second protrusion 42 is provided across the opening width of the second air intake 22B at a position close to the lip portion 24 of the second air intake 22B on the outer surface of the side cover 5.

[0059] FIG. 10 is an XY cross-sectional view of the first protrusion 41 and the second protrusion 42. As shown in FIG. The first protrusion 41 and the second protrusion 42 have shapes that are symmetrical from front to back. Here, the first protrusion 41 will be described, and a description of the second protrusion 42 will be omitted.

[0060] The first protrusion 41 has an inverted T-shaped cross section, which is formed by a base 44 that contacts the outer surface of the side cover 5 and a wall 45 that protrudes outward (in the positive direction of the Y axis) from the midpoint between the front and rear of the base 44.

[0061] The height of the first protrusion 41 (the length from the outer surface of the side cover 5; the length in the Y-axis direction) is set to be 0.5 to 0.8 times the height direction length Rh (the thickness of the lip portion 24) of the lip portion 24 of the first air intake 21B (0.8 times (0.8Rh) in the example of FIG. 10). The connection between the base portion 44 and the wall portion 45 is connected by a smoothly curved surface.

[0062] FIG. 11 is a diagram for explaining an outline of the flow of wind generated by running in the ventilation structure 10B. Of the traveling winds, the first traveling wind W1 that reaches the first air intake 21B is introduced into the first air intake 21B. The introduced first traveling wind W1 passes through the radiator 7 installed in the underfloor duct 14 and is used for heat exchange. The first traveling wind W1 passes through the radiator 7 and heads toward the second air intake 22B.

[0063] On the other hand, of the traveling wind that was not introduced into the first air intake 21B, the second traveling wind W2 that approaches the second protrusion 42 hits the wall 45, has its flow direction suddenly changed, and is thrown up outward, causing boundary layer separation and generating turbulence including lateral vortices. The vortices and turbulence generated by the second traveling wind W2 being thrown up create a negative pressure area 9 in the vicinity of the second air intake 22B. In other words, the second protrusion 42 functions as a negative pressure area forming structure.

[0064] The negative pressure area 9 exerts a suction effect that sucks air from the underfloor duct 14 that is connected to the second air intake 22B. Therefore, the first traveling wind W1 that passes through the radiator 7 and heads toward the second air intake 22B is discharged more effectively than in a configuration without the second protrusion 42, increasing the amount of ventilation. The suction effect of the negative pressure area 9 also extends to the first air intake 21B through the underfloor duct 14, improving the air introduction efficiency (which can also be said to be intake efficiency) at the first air intake 21B.

[0065] When the traveling direction of the railway vehicle 3 reverses front to back, the air flow in the ventilation structure 10B is also reversed from the front to the back of the example in Figure 11. That is, part of the running wind is introduced from the second air intake 22B, passes through the underfloor duct 14, and passes through the radiator 7. The air that has exchanged heat in the radiator 7 is exhausted from the first air intake 21B. Meanwhile, part of the running wind that reaches the first protrusion 41 (wind corresponding to the second running wind W2 in Figure 11) is thrown up by the wall 45 of the first protrusion 41. Vortices and turbulence caused by the throwing up create a negative pressure area 9 in the vicinity of the first air intake 21B. That is, the first protrusion 41 functions as a negative pressure area forming structure.

[0066] Third Embodiment Next, a third embodiment to which the present invention is applied will be described. The ventilation structure 10C of the third embodiment is basically realized in the same way as the ventilation structure 10B of the second embodiment, but the shape of the XY cross section of the negative pressure area forming structure is different. Hereinafter, differences from the second embodiment will be mainly described, and components similar to those of the second embodiment will be assigned the same reference numerals and will not be described again.

[0067] FIG. 12 is an XY cross-sectional view showing an example of the shape of the first protrusion 51 and the second protrusion 52 in the ventilation structure 10C. The ventilation structure 10C of the third embodiment is basically the same as the ventilation structure 10B of the second embodiment, but has a first convex portion 51 instead of the first convex portion 41 of the second embodiment, and has a second convex portion 52 instead of the second convex portion 42 of the second embodiment. The first protrusion 51 is provided across the opening width of the first air intake 21B (the length of the opening along the Z-axis direction) at a position close to the lip portion 24 of the first air intake 21B on the outer surface of the side cover 5. The second protrusion 52 is provided across the opening width of the second air intake 22B at a position close to the lip portion 24 of the second air intake 22B on the outer surface of the side cover 5.

[0068] The XY cross section of the first protrusion 51 is substantially semicircular. The height of the first protrusion 51 (length from the outer surface of the side cover 5; length in the Y-axis direction) is 0.5 to 0.8 times the height direction length Rh of the lip portion 24 of the first air intake 21B (thickness of the lip portion 24) (0.8 times (0.8Rh) in the example of FIG. 12). The second protrusion 52 has a shape symmetrical to the first protrusion 51 in the front-to-rear direction.

[0069] The flow of the traveling wind in the ventilation structure 10C is similar to that in the ventilation structure 10B of the second embodiment, and the second traveling wind W2 is thrown up by the first convex portions 51 and the second convex portions 52, causing a negative pressure region 9 to be generated.

[0070] [Effects of each embodiment] Next, the effects of the above-described embodiments will be described based on the results of experiments. 13 is a graph comparing the wind speed ratio of the inflow wind speed with that of a conventional ventilation structure 90 (conventional configuration). The inflow wind speed for comparison was the average value of wind speeds measured at multiple locations upstream of the radiator 7 inside the underfloor duct 14. The target value calculated from the air volume required to cool the radiator 7 was a wind speed ratio of 0.85 with respect to the conventional ventilation structure 90.

[0071] Both the first and second embodiments achieved the target wind speed ratio of 0.85, allowing sufficient air to circulate to cool the radiator 7. Furthermore, a configuration in which the first recess 31 and the second recess 32 were omitted from the first embodiment (shown as "No first recess or second recess" in the graph) also achieved a lower wind speed ratio than the configuration in the first embodiment, but still reached the target value. However, in the second embodiment, the dimensions of the air intake are smaller than those of the ventilation structure 10 in the first embodiment. Therefore, a configuration in which the first protrusion 41 and the second protrusion 42 were omitted from the second embodiment (shown as "No first protrusion or second protrusion" in the graph) did not reach the target value. This demonstrates that the first recess 31 and the second recess 32, as well as the first protrusion 41 and the second protrusion 42, function effectively as negative pressure region-forming structures and contribute to ensuring a sufficient flow rate.

[0072] FIG. 14 is a graph comparing wind noise with a conventional ventilation structure 90 (conventional configuration) as a reference. Both the first and second embodiments are able to reduce wind noise compared to conventional designs. Furthermore, a configuration in which the first recess 31 and the second recess 32 are omitted from the first embodiment achieves substantially the same wind noise reduction effect as the first embodiment. However, focusing on the second embodiment, it can be seen that a configuration in which the first protrusion 41 and the second protrusion 42 are omitted is more effective at reducing wind noise. In other words, the first protrusion 41 and the second protrusion 42 contribute significantly to ensuring the flow rate, as shown in FIG. 13, but also have the effect of increasing wind noise. It can be said that the balance between the flow rate and wind noise needs to be considered when determining the height of the first protrusion 41 and the second protrusion 42.

[0073] Figure 15 is a graph comparing the wind speed ratio of the inflow wind speed depending on the protrusion shape (shape of the convex portion) of the negative pressure area forming structure, and shows the wind speed ratio based on a configuration in which the negative pressure area forming structure (first recess 31, second recess 32) is omitted from the first embodiment.

[0074] If the height of the protrusions (shapes of the convex portions) is the same, the second embodiment, in which the cross-sectional shape is an inverted T, such as the first convex portion 41 and the second convex portion 42, has a higher inflow wind speed and therefore a larger flow rate than the third embodiment, in which the cross-sectional shape is a substantially semicircular shape, such as the first convex portion 51 and the second convex portion 52. In other words, the cross-sectional shape is an inverted T, which can form a more effective negative pressure region 9.

[0075] Figure 16 is a graph comparing wind noise caused by different heights of the protrusion shape (shape of the convex portion) of the negative pressure area forming structure, and shows the increase in noise level compared to a configuration in which the negative pressure area forming structure (first recess 31, second recess 32) is omitted from the first embodiment. When we look at the shape of the protrusions of the negative pressure area forming structure, the second embodiment with its inverted T-shaped cross section tends to produce more wind noise than the third embodiment with its roughly semicircular cross section, but the difference is slight. Also, when we look at the height of the protrusions of the negative pressure area forming structure, the latter is naturally higher than the "0.3Rh" and "0.5Rh" ones, but the difference is slight.

[0076] From the above experimental results, it can be said that, among the above embodiments, the configuration of the ventilation structure 10 of the first embodiment is the most effective. Furthermore, in the second and third embodiments, there is a trade-off between the inflow wind speed and the wind noise (when a high inflow wind speed is required, the effect of reducing wind noise decreases (conversely, the wind noise increases)), and it is therefore advisable to determine the shape and height of the protrusions of the negative pressure area forming structure based on various conditions such as the overall dimensions of the railway vehicle 3 and the expected running speed.

[0077] Although an example of an embodiment to which the present invention is applied has been described above, the forms to which the present invention can be applied are not limited to the above-described embodiment. For example, instead of the negative pressure region forming structure of the first embodiment, the negative pressure region forming structure of the second and third embodiments may be applied.

[0078] Furthermore, in the above-described embodiments, examples of ventilation structures 10, 10B, and 10C for supplying cooling air to a water-cooled circulation type radiator 7 for cooling a power conversion device have been described. However, since ventilation structures 10, 10B, and 10C are structures that can simultaneously suppress wind noise and ensure ventilation volume, they can be applied not only to cooling applications for supplying cooling air to radiator 7, but also to ventilation applications for ventilating indoor air in passenger compartments and specific private rooms (e.g., toilets) of railway vehicles, etc.

[0079] Furthermore, in the above embodiment, an example has been shown in which the water-cooled circulation type radiator 7 is disposed under the floor of the railway vehicle 3 and the ventilation structure 10 opens in the side cover 5, but the position of the radiator 7 and the position of the opening of the ventilation structure 10 can be changed as appropriate. For example, the radiator 7 may be disposed on the roof of the railway vehicle 3, in the upper interior space, or inside a side wall. Accordingly, the first air intake 21 and the second air intake 22 of the ventilation structure 10 may also be opened on the top or side surface of the railway vehicle 3 (for example, on the side surface above the side cover 5). [Explanation of symbols]

[0080] 3. Railway vehicles 5...Side cover 7...Radiator 9...Negative pressure area 10, 10B, 10C...Ventilated structure 14...Underfloor duct 21...First air intake 22...Second air intake 23...Opening 24...Lip 26…Ventilation slope 31...First recess 32...Second recess 33...First slope 35...Second slope 41...First convex part 42...Second convex part Ah...Opening height Al…Full length Aw...Opening width

Claims

1. A ventilation structure comprising a pair of air intakes provided symmetrically on the outer surface of a railway vehicle in the direction of travel and the opposite direction, in which running wind introduced from the air intake on the upstream side in the direction of travel is guided to a duct and exhausted from the air intake on the downstream side in the direction of travel, Each of the pair of air intakes has a structure in which the opening width and the ventilation cross-sectional area gradually increase from the tip of the air intake toward the other air intake, two negative pressure area forming structures for forming a negative pressure area between the pair of air intakes; one of the two negative pressure area forming structures is located near an air intake on the upstream side in the traveling direction, and the other is located near an air intake on the downstream side in the traveling direction; the pair of air intakes and the two negative pressure area forming structures are linearly arranged on the outer surface, Ventilated structure.

2. In each of the pair of air intakes, the inclination angle of the ventilation inclined surface with respect to the outer surface is 15 degrees or more and 25 degrees or less. The ventilation structure according to claim 1.

3. The two negative pressure area forming structures are each a recess. The ventilation structure according to claim 1.

4. the recess has a first slope closer to the air intake and a second slope closer to the other air intake, The inclination angle of the first slope is greater than the inclination angle of the second slope. The ventilation structure according to claim 3.

5. The inclination angle of the second slope is an angle that induces boundary layer separation. The ventilation structure according to claim 4.

6. The two negative pressure area forming structures are each a convex portion. The ventilation structure according to claim 1.

7. The two negative pressure area forming structures are each provided across the opening width at the adjacent positions. The ventilation structure according to any one of claims 1 to 6.

8. The two negative pressure area forming structures each have a height length from the outer surface that is 0.5 to 0.8 times the height length of the lip portion of the air intake. The ventilation structure according to any one of claims 1 to 6.

9. A railway vehicle equipped with the ventilation structure according to any one of claims 1 to 6.

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