Snow suppression structure

Abstract

To provide a new technology that suppresses snow accumulation on the end-filled portion. [Solution] The snow accumulation suppression structure 20 suppresses snow accumulation 9 on the end cover portion 4 that separates the equipment installation space 8 covered by the underfloor cover portion 6 and the bogie storage space 10 in the railway vehicle 2. The snow accumulation suppression structure 20 includes a stepped portion 22 provided at the connection point between the end cover portion 4 and the underfloor cover portion 6. The stepped portion 22 has a slope 24 whose lower surface height position gradually decreases to reach the height position of the lower surface of the underfloor cover portion 6.

Description

Technical Field

[0001] The present invention relates to a snow adhesion suppression structure for suppressing snow adhesion to a railway vehicle.

Background Art

[0002] Regarding countermeasures against snow adhesion for railway vehicles running in snowfall areas, aerodynamic countermeasures, countermeasures using heat sources such as snow melting heaters, material countermeasures, etc. are known. For example, Patent Document 1 describes a configuration provided with an intake portion for taking in running wind on the side cover of a bogie and a nozzle portion for blowing out the taken-in air toward an end blocking plate.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The "end blocking portion (the end blocking plate is a representative example)" that separates the equipment installation space covered by the under-floor blocking portion (the under-floor blocking plate is a representative example) from the bogie accommodation space is one of the key points in snow adhesion countermeasures.

[0005] Figs. 10 and 11 are diagrams for explaining snow adhesion at the end blocking portion 4 of a conventional railway vehicle 2J. In Figs. 10 and 11, a state where the railway vehicle 2J is running from the right to the left in the figure is shown. The white arrows in Figs. 10 and 11 indicate the running direction, the mesh-patterned arrows indicate the direction of the running wind, and the black arrows indicate the relative movement of snow particles with respect to the railway vehicle 2J.

[0006] When the railway vehicle 2J runs on a track 12 with snowfall or snow accumulation, the snow is lifted up, and due to the relative movement relationship, snow adhesion 9 occurs at the end blocking portion 4 on the rear side of the bogie accommodation space 10 (the right side in Figs. 10 and 11; the downstream side with reference to the running wind).

[0007] Figure 11 is an enlarged view of the rear end capping section 4 of the bogie housing space 10 in Figure 10. Experiments conducted on a model train running device to investigate the distribution and progression of snow accumulation 9 on the end capping section 4 showed that the initial snow accumulation 9 starts at the lower edge of the end capping section 4, particularly near the rear of the wheels 14. Then, as the distance traveled through the snowy section increases, the snow accumulation 9 on the lower edge of the end capping section 4 grows in the direction of the rails (growing thicker), and also progresses upward from the starting point and to the left and right (towards the sleepers), until finally the entire end capping section 4 is covered with snow accumulation 9.

[0008] When the snow accumulation 9 on the lower edge of the end-closing portion 4 grows and protrudes in a cornice-like shape, the protruding snow accumulation 9 causes the airflow containing snow under the vehicle floor to be drawn more into the bogie, which tends to promote snow accumulation 9 inside the bogie.

[0009] The end capping section 4 is prone to snow accumulation because its normal direction is almost directly facing the snow-laden airflow. Furthermore, the large snow accumulation area of ​​the end capping section 4 contributes to the high density and mass of the accumulated snow 9, making it more likely for the impact of the snow falling in clumps to be significant.

[0010] The problem that this invention aims to solve is to provide a new technology for suppressing snow accumulation on the end-filled portion. [Means for solving the problem]

[0011] The first invention for solving the above problems is a snow accumulation suppression structure for suppressing snow accumulation on an end-fill portion that separates an equipment installation space covered by an underfloor closing portion from a bogie storage space in a railway vehicle, comprising a stepped portion provided at the connection point between the end-fill portion and the underfloor closing portion, wherein the stepped portion has a slope in which the height position of the lower surface gradually decreases to the height position of the lower surface of the underfloor closing portion.

[0012] The snow accumulation suppression structure of the first invention, by having a stepped section, allows most of the airflow that would normally hit the starting point of snow accumulation in a conventional structure to flow backward along the slope without hitting the lower edge of the end-closing section. In other words, snow accumulation on the lower edge of the end-closing section is less likely to occur, and it becomes possible to prevent it from becoming the starting point of snow accumulation. Furthermore, the airflow flowing along the slope passes through a space where the gap with the ground narrows in the height direction, increasing the tangential velocity and producing a greater effect in suppressing snow accumulation.

[0013] The snow accumulation suppression structure of the first invention can be made even more effective, as described below.

[0014] The second invention is a snow accumulation suppression structure, wherein the stepped portion has a planar portion substantially parallel to the lower surface of the underfloor blocking portion, connected to the outer surface of the end blocking portion at a predetermined angle, and the slope is located at a position further away from the end blocking portion than the planar portion in the rail direction.

[0015] The third invention is a snow accumulation suppression structure, wherein the slope has a maximum inclination portion located in the 2 / 3 portion when the stepped portion is divided into three equal parts in the rail direction, with the 1 / 3 portion closer to the trolley storage space and the 2 / 3 portion further away from the trolley storage space.

[0016] The fourth invention is the snow accumulation suppression structure described above, wherein the stepped portion has a length in the rail direction that is at least twice the length in the height direction.

[0017] The fifth invention is the snow accumulation suppression structure described above, further comprising a recess provided in the rail direction at a position further away from the step portion from the bogie housing space.

[0018] The sixth invention is the snow accumulation suppression structure described above, wherein the recessed portion has a first inclined portion that extends from the side far from the carriage accommodation space toward the deepest part of the recess in the rail direction, and a second inclined portion that extends from the side close to the carriage accommodation space toward the deepest part of the recess, and the second inclined portion has a larger inclination angle than the first inclined portion, which is the snow accumulation suppression structure.

Brief Description of the Drawings

[0019] [Figure 1] Schematic side view of a railway vehicle showing an example structure of a snow accumulation suppression structure. [Figure 2] Enlarged view showing an example configuration of a stepped portion. [Figure 3] Diagram for explaining the air flow around the stepped portion at the rear side. [Figure 4] Diagram for explaining the air flow around the stepped portion at the front side. [Figure 5] Graph showing the relationship between the running distance and the dimensionless volume of snow accumulation. [Figure 6] Graph showing the difference in noise level depending on the presence or absence of a recessed portion. [Figure 7] Diagram for explaining a modification example. [Figure 8] Diagram for explaining a modification example. [Figure 9] Diagram for explaining a modification example. [Figure 10] Diagram for explaining snow accumulation on the end blocking portion in a conventional railway vehicle. [Figure 11] Enlarged view of FIG. 10.

Modes for Carrying Out the Invention

[0020] Hereinafter, an example of an embodiment to which the present invention is applied will be described. However, it is needless to say that the forms to which the present invention can be applied are not limited to the following embodiments. In the following description, the front side / rear side will be described as the direction based on the running direction of the railway vehicle. When described based on the running wind, it will be described as the upstream side / downstream side.

[0021] [ Figure 1 is a schematic side view of a railway vehicle 2 showing an example of the structure of the snow accumulation suppression structure 20. The snow accumulation suppression structure 20 has stepped sections 22 (22a, 22b) on the front side (upstream side of the airflow) and the rear side (downstream side of the airflow) with respect to the direction of travel. Since the railway vehicle 2 can travel in both uphill and downhill directions, it has a front stepped section 22a and a rear stepped section 22b. From the viewpoint of snow accumulation, the rear stepped section 22b is important, so the following explanation will focus on the rear stepped section 22b. The side view shape of the front stepped section 22a and the side view shape of the rear stepped section 22b are basically symmetrical front to back. Of course, due to constraints such as the structure of the railway vehicle 2, there may be some parts where front to back symmetry is not maintained.

[0022] The stepped portion 22 is provided at the connection point between the end-fill portion 4 and the underfloor-fill portion 6. The stepped section 22 has a width that extends to the entire width of the railway vehicle 2.

[0023] Figure 2 is an enlarged view showing an example of the configuration of the stepped section 22. The stepped section 22 has a planar section 23 that is substantially parallel to the lower surface of the underfloor blocking section 6, connected to the outer surface of the end blocking section 4 at a predetermined angle, and has a slope 24 at a position further away from the end blocking section 4 than the planar section 23 in the rail direction.

[0024] The slope 24 has a length L in the rail direction that is at least twice the length in the height direction (the depth Ds of the step 22 assuming that the outer corner of the vehicle is trimmed upwards from the lower surface of the underbody cover 6). Furthermore, the height of the lower surface of the slope 24 gradually decreases in the direction of the airflow from the side of the end cover 4, until it reaches the height of the lower surface of the underbody cover 6. The position of the slope 24 with the maximum incline θmax is located in the 2 / 3 portion when the step 22 is divided into three equal parts by dividing the length L in the rail direction into the 1 / 3 portion closer to the bogie storage space 10 and the 2 / 3 portion further away from the bogie storage space 10.

[0025] More specifically, the depth Ds of the stepped section 22 (length from the bottom surface of the underfloor sealing section 6 to the flat section 23) shall be between 100 mm and 250 mm. If the depth Ds is made larger than this, depending on the type of railway vehicle 2, it may become difficult to install the stepped section 22 itself due to constraints on the equipment installation space 8 under the vehicle floor.

[0026] The slope 24 is formed as a series of gently curving surfaces to prevent boundary layer separation of the airflow. When viewed from the side, the slope 24 may have a single streamlined shape or a shape formed by combining multiple streamlined shapes. However, the angle of the maximum inclination θmax of the slope 24 (maximum inclination angle) shall be 15° or more and 45° or less.

[0027] If the maximum inclination angle of the slope 24 is greater than 45°, the rail-direction length L of the step section 22 is shortened, making it easier to secure equipment installation space 8 under the vehicle floor. However, the angle of snow collision with the slope 24 (the angle between the tangential direction of the slope 24 and the advection direction of the snow) becomes larger, making it easier for snow to accumulate on the slope 24 9. In particular, the connection section between the slope 24 and the underfloor closing section 6 is a place where snow accumulation 9 is likely to occur, so a smooth shape is preferable.

[0028] If the maximum inclination angle of the slope 24 is reduced to less than 15°, snow accumulation 9 on the slope 24 will be less likely to occur. However, the length L of the stepped section 22 in the rail direction will increase, which will narrow the equipment installation space 8, making it difficult to provide the stepped section 22 at all.

[0029] The stepped section 22 has a recessed section 30 located further from the bogie storage space 10 in the rail direction than the lower end of the slope 24. In other words, the recessed section 30 is located near the connection point from the underfloor sealing section 6 to the slope 24 of the stepped section 22. There may also be a horizontal straight section between the slope 24 and the recessed section 30.

[0030] The recessed portion 30 has a first inclined portion 31 that extends from the side furthest from the bogie storage space 10 toward the deepest part of the recess in the rail direction, and a second inclined portion 32 that extends from the side closer to the bogie storage space toward the deepest part of the recess. The inclination angle of the second inclined portion 32 from the lower surface of the underfloor covering portion 6 is greater than that of the first inclined portion 31.

[0031] The recessed portion 30 exerts its effect at the stepped portion 22a located on the upstream (front) side of the bogie. This effect is to reduce aerodynamic noise when the running air flows into the bogie housing space 10. The stepped portion 22 shown in Figure 2 is the rear stepped portion 22b, but assuming that the running direction and the direction of the running air shown in Figure 2 are reversed, and the stepped portion 22 shown in Figure 2 corresponds to the front stepped portion 22a, as shown in Figure 4, the recessed portion 30 is provided to separate the boundary layer at the boundary position with the slope 24 before the running air that flows into the stepped portion 22 along the underbody sealing portion 6 flows into the slope 24.

[0032] The depth Dh of the recessed section 30 (vertical length relative to the lower surface of the underbody sealing section 6) is the length from the lower surface of the underbody sealing section 6 to the connection point between the first inclined section 31 and the second inclined section 32. The depth Dh shall be between 50 mm and 100 mm. If the depth Dh exceeds 100 mm, the effect of boundary separation of the flow under the vehicle body will be easier to obtain, but the overall length of the recessed section 30 in the rail direction will increase according to the depth Dh of the recess, making it difficult to provide the stepped section 22 itself due to the constraints of the equipment installation space 8.

[0033] The first inclined section 31 is a slope that slopes downward from the lower surface of the underfloor sealing section 6 to its deepest point, and its inclination angle is set to be between 15° and 30°. If the inclination angle is greater than this, the possibility of boundary layer separation occurring in the first inclined section 31 increases, preventing airflow from entering the recessed section 30, and reducing the noise suppression effect of the recessed section 30, which will be described later.

[0034] The second inclined section 32 slopes upward from the deepest point towards the end of the stepped section 22, and its inclination angle is set steeper than that of the first inclined section 31. The inclination angle of the second inclined section 32 is set to be between 45° and 90°.

[0035] Figure 3 is a diagram illustrating the airflow around the rear step section 22b with respect to the direction of travel. As mentioned above, in the conventional structure without the stepped section 22b, the initial snow accumulation 9 starts and grows from the lower edge of the end-closing section 4, especially near the rear (downstream) of the wheel 14 (see Figures 10 and 11). However, in the railway vehicle 2 equipped with the snow accumulation suppression structure 20, by providing the stepped section 22b on the rear side of the bogie, most of the running air that would hit the lower edge of the end-closing section 4 in the conventional structure flows backward along the slope 24 without hitting the end-closing section 4. In other words, snow accumulation 9 on the lower edge of the end-closing section 4 becomes less likely than in the conventional structure.

[0036] In conventional structures, when snow accumulation 9 on the lower edge of the end-closing portion 4 grew, its shape caused the running air to circulate to the upper part of the bogie storage space 10 (see Figure 11). However, in this embodiment, because of the stepped portion 22b, snow accumulation 9 on the lower edge of the end-closing portion 4 is suppressed, resulting in significantly less snow accumulation 9 on the upper part of the bogie storage space 10 compared to conventional structures.

[0037] The airflow along the slope 24 reaches the recessed section 30, but by creating a smooth connection between the first inclined section 31 and the underbody sealing section 6, the presence of the recessed section 30 is unlikely to cause any problems.

[0038] Figure 4 is a diagram illustrating the airflow around the front stepped section 22a. The airflow attempting to pass over the upstream step 22a travels along the underside of the step 22a and first flows into the recess 30. At this time, the airflow, which has been smoothly drawn towards the deepest point along the first inclined section 31, is bounced up along the second inclined section 32, causing a sudden change in flow direction. This bounce causes boundary layer separation in the airflow. As a result of boundary layer separation, the airflow that has passed through the second inclined section 32 flows away without following the slope 24. In other words, its inflow into the bogie storage space 10 is suppressed. By reducing the inflow into the bogie storage space 10, noise around the bogie is suppressed.

[0039] Figure 5 is a graph showing the relationship between the distance traveled and the dimensionless volume of snow accumulation 9, obtained from tests that reproduce actual driving conditions. As shown in this graph, when the snow accumulation suppression structure 20 is provided, snow accumulation 9 is effectively suppressed after a distance of approximately 800m.

[0040] Figure 6 is a graph showing the difference in noise levels with and without the recessed area 30, obtained from tests that reproduced actual driving conditions. As shown in this graph, when the recessed area 30 is provided, the noise level is effectively suppressed compared to when the recessed area 30 is not provided.

[0041] As described above, according to this embodiment, it is possible to suppress snow accumulation on the end sealing portion 4 that separates the equipment installation space 8 covered by the underfloor sealing portion 6 from the bogie housing space 10 in the railway vehicle 2. In other words, the railway vehicle 2 to which the snow accumulation suppression structure 20 of this embodiment is applied has stepped portions 22 (22a, 22b) on both the front and rear sides of the bogie housing space 10. At the stepped portion 22b on the rear side (downstream side of the running air), a snow accumulation suppression effect is obtained. At the stepped portion 22a on the front side (upstream side of the running air), boundary layer separation of the running air is promoted by the recessed portion 30, as a result of suppressing the flow of running air into the bogie housing space 10, and aerodynamic noise (noise) is suppressed.

[0042] Furthermore, since the stepped portion 22 is limited to the lower part of the end-closing portion 4, the impact on reducing the equipment installation space 8 under the vehicle floor is small. Therefore, it is easy to apply to existing railway vehicles. In addition, the snow accumulation suppression structure 20 does not affect the vehicle clearance.

[0043] Furthermore, the stepped section 22 has no movable parts or electrically controlled components. A heat source such as a snow-melting heater is also unnecessary. The stepped section 22 can be constructed using only fixed structures. Therefore, it offers advantages in terms of maintenance and cost.

[0044] [Differentiation] Although an example of an embodiment to which the present invention is applied has been described, the forms to which the present invention can be applied are not limited to the above-described form, and components can be added, omitted, or modified as appropriate.

[0045] (Variation 1) In the above embodiment, the end-closing portion 4 was illustrated and described as a vertical wall, but it is not limited to this. For example, as shown in Figure 7, it may be configured to be inclined in the front-rear direction.

[0046] (Variation 2) In the above embodiment, the slope 24 is exemplified as a smoothly continuous streamlined surface in side view, but it is not limited to this. For example, it may be composed of one or more linear inclined surfaces in side view, such as the slope 24C of the stepped section 22C shown in Figure 8, or the slope 24D of the stepped section 22D shown in Figure 9. In this case as well, it is preferable that the maximum inclination of the slope is located in the 2 / 3 portion when the length of the stepped sections 22C and 22D in the rail direction is divided into three equal parts: the 1 / 3 portion closer to the bogie storage space 10 and the 2 / 3 portion further away from the bogie storage space 10.

[0047] (Variation 3) In the above embodiment, an example was shown in which the stepped portion 22 is provided over the entire width of the railway vehicle 2, but it is not limited to this. The snow accumulation suppression effect is reduced compared to the above embodiment, but it may also be configured to be provided only over a part of the entire width of the railway vehicle 2.

[0048] (Modification #4) In the above embodiment, an example was shown in which the same snow accumulation suppression structure 20 is provided on both the front and rear sides based on the direction of travel of the railway vehicle 2, but the invention is not limited to this. If the direction of travel of the railway vehicle 2 is limited, for example, the snow accumulation suppression structure 20 on the front side may be omitted. Also, for example, the slope 24 of the snow accumulation suppression structure 20 on the front side may be omitted while retaining the recessed portion 30. Furthermore, for example, the slope 24 of the snow accumulation suppression structure 20 on the front side may be simplified from a streamlined shape to a straight inclined surface. [Explanation of Symbols]

[0049] 2…Railway vehicles 4…End capping 6... Underfloor sealing section 8…Equipment installation space 9... Snow accumulation 10... Trolley storage space 20…Snow accumulation suppression structure 22... Stepped section 24...Slope 30… recessed area 31...First slope part 32…Second slope part

Claims

1. A snow accumulation suppression structure for suppressing snow accumulation on the end seal portion that separates the equipment installation space covered by the underfloor seal portion from the bogie housing space in a railway vehicle, A stepped portion is provided at the connection between the end-closing portion and the underfloor-closing portion. Equipped with, The stepped portion has a slope in which the height of the lower surface gradually decreases until it reaches the height of the lower surface of the underfloor blocking portion. Snow accretion suppression structure.

2. The stepped portion has a planar section substantially parallel to the lower surface of the underfloor blocking portion, connected to the outer surface of the end blocking portion at a predetermined angle, and the slope is located at a position further away from the end blocking portion than the planar section in the rail direction. The snow accumulation suppression structure according to claim 1.

3. The slope has its maximum incline portion located in the 2 / 3 portion when the stepped portion is divided into three equal parts in the rail direction, with the 1 / 3 portion being closer to the trolley storage space and the 2 / 3 portion being further away from the trolley storage space. The snow accumulation suppression structure according to claim 1.

4. The stepped portion has a length in the rail direction that is at least twice the length in the height direction. The snow accumulation suppression structure according to claim 1.

5. A recessed portion provided in the rail direction at a position further away from the stepped portion from the bogie housing space, A snow accumulation suppression structure according to any one of claims 1 to 4, further comprising the above.

6. The recessed portion has, in the rail direction, a first inclined portion that extends from the side furthest from the bogie housing space toward the deepest part of the recess, and a second inclined portion that extends from the side closest to the rail toward the deepest part of the recess. The second inclined portion has an inclination angle greater than that of the first inclined portion. The snow accumulation suppression structure according to claim 5.

Images