Vehicle vibration suppression structure

Abstract

To provide a vehicle vibration suppression structure capable of suppressing vibrations occurring in a vehicle by changing the shape of the lower part of the vehicle body. [Solution] The vibration suppression structure 10 suppresses vibrations that occur in train cars due to fluctuating aerodynamic forces generated when the train is traveling, and the distance S between the lower parts of both side body sections 9R, 9L of the car is narrower than the width W of the car body bottom 8 of the car, and both edges of the car body bottom 8 protrude outward beyond the lower parts of both side body sections 9R, 9L. The distance S between both side body sections 9R, 9L gradually narrows toward the car body bottom 8. The lower parts of both side body sections 9R, 9L are the lower parts of the wainscoting 9c that form the side structure of the car body 5 of the car. Both edges of the car body bottom 8 protrude continuously in the length direction of the car body 5 of the car. Both edges of the car body bottom 8 of the last car 3C of the train protrude.

Description

[Technical Field]

[0001] The present invention relates to a vibration suppression structure for a vehicle that suppresses vibrations that occur in a vehicle of a train due to fluctuating aerodynamic forces that are generated when the train is running. [Background technology]

[0002] In past on-board tests accompanying speed increases, lateral vibration of vehicles was observed. FIG. 13 is a graph showing an increase in pressure fluctuations in the last car of a train. The vertical axis in FIG. 13 represents the effective value (Pa) of pressure (differential pressure) fluctuations, and the horizontal axis represents the distance (m) from the front of the train. A to D represent the type of train. As shown in FIG. 13, regardless of the type of train, the effective value of pressure fluctuations shows a certain tendency depending on the distance from the front, increasing from approximately the sixth to eighth car from the front, and then remaining constant. It has been found that the last car in particular vibrates more than cars at other positions in the train formation (see, for example, Non-Patent Document 1). Non-Patent Document 1 shows that the effective value of pressure fluctuations increases from approximately the sixth to eighth car from the front, then reaches a constant value, and then suddenly increases at the rear of the train.

[0003] Subsequent research has investigated the relationship between lateral vibration and pressure fluctuations on the sides of a vehicle, and confirmed that vehicle vibration is caused by fluctuating aerodynamic forces due to differential pressure (see, for example, Non-Patent Document 2). Non-Patent Document 2 shows that pressure fluctuations increase particularly in the rearmost vehicle due to the influence of separated flow caused by the shape of the rear vehicle.

[0004] Recent research into fluctuating aerodynamic forces has revealed the structure of large-scale serpentine flows that develop in the gaps between the vehicle and the floor or wall in a tunnel, and has revealed that the serpentine flows are the cause of the fluctuating aerodynamic forces that cause vehicle turbulence (see, for example, Non-Patent Document 3). Furthermore, using a model of the actual shape, it has been confirmed that underfloor serpentine flows develop even in open sections, and their characteristics have been investigated in detail (see, for example, Non-Patent Document 4).

[0005] The relationship between the fluctuating aerodynamic forces caused by underfloor serpentine flow and the phenomenon of increased fluctuating aerodynamic forces on the rearmost car was unclear, but recent research has investigated the relationship between the two in lighted sections (see, for example, Non-Patent Documents 5 and 6). The research results revealed that the underfloor serpentine flow strengthens the fluctuating aerodynamic forces on the rearmost car. Furthermore, differences in the increase in fluctuating aerodynamic forces on the rearmost car were observed depending on the shape of the rear end. Based on these findings, we focused on the relationship between the underfloor serpentine flow and the shape of the rearmost car, and investigated, from an unprecedented perspective, methods for suppressing the fluctuating aerodynamic forces that cause turbulence on the rearmost car.

[0006] The fluctuating aerodynamic force on the last car is (1) Aerodynamic forces due to the shape of the rearmost car (difference from the aerodynamic forces of the middle cars) (2) Aerodynamic forces caused by serpentine flow under the floor It is thought to be caused by two factors: (1) The magnitude of fluctuations in (1) differs depending on whether or not serpentine flow is present, and serpentine flow strengthens fluctuating aerodynamic forces. In other words, if conditions are set such that serpentine flow does not occur under the floor (car shape in which the bogies and cavity are omitted and the underfloor surface of the entire train is smooth), and (2) can be ignored, the fluctuations in (1) will be small. Therefore, measures to mitigate the effects of serpentine flow acting on the last car are important in reducing fluctuating aerodynamic forces.

[0007] Measures have been proposed to reduce the vibration of railway vehicles from an aerodynamic perspective. For example, assuming a vehicle traveling in a tunnel, vertical partitions are installed under the floor to suppress the generation of vortices near the underfloor (see, for example, Patent Documents 1 and 2). Methods for suppressing serpentine flow under the vehicle floor include changing the shape of the vehicle or blowing air from the ground (see, for example, Patent Document 3), and a method has also been devised to suppress serpentine flow that spreads inside a tunnel (see, for example, Patent Document 4). [Prior art documents] [Patent documents]

[0008] [Non-Patent Document 1] Koji Nakade, "Fluctuating Aerodynamic Forces of High-Speed ​​Trains Running in Tunnels", RRR, Vol. 73, No. 11 (2016.11), pp. 32-35

[0009] [Non-patent document 2] Masahiro Suzuki, "Aerodynamic Forces Acting on a Vehicle Running in a Tunnel", Railway Technical Research Institute Report, Vol. 14, No. 9, (September 2000), pp. 37-42

[0010] [Non-patent document 3] Takaji Nakade and two others, "Generation Mechanism of Fluctuating Aerodynamic Forces Related to Railway Vehicle Motions During Tunnel Travel (LES of Large-Scale Flow Structures in a Simple-Geometry Railway Vehicle Model)," Transactions of the Japan Society of Mechanical Engineers, Vol. 87, No. 893 (2021), DOI: 10.1299 / transjsme.20-00366.

[0011] [Non-patent document 4] Koji Nakade et al., "Meandering Flow Under the Vehicle Floor in a Railway Vehicle Model Including a Bogie (LES of Large-Scale Flow Structures in a Realistic Railway Vehicle Model)", Transactions of the Japan Society of Mechanical Engineers, Vol. 87, No. 894 (2021), DOI: 10.1299 / transjsme.20-00398.

[0012] [Non-Patent Document 5] Takumi Abe et al., "LES on the influence of serpentine flow under the floor of a railway vehicle on the fluctuating aerodynamic forces of the last car", Japan Society of Fluid Mechanics Annual Meeting 2022 (Presentation Paper), (September 2022), pp. 1-9

[0013] [Non-patent document 6] Takumi Abe et al., "DMD Analysis of Serpentine Flow Under the Floor of a Railway Vehicle and Fluctuating Aerodynamic Forces on the Last Car", Annual Meeting of the Japan Society of Fluid Mechanics 2023 (Presentation Paper), (September 2023), pp. 1-8

[0014] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-090849

[0015] [Patent Document 2] Japanese Patent Application Laid-Open No. 2002-053037

[0016] [Patent Document 3] Japanese Patent Application Publication No. 2016-097852

[0017] [Patent Document 4] Japanese Patent Application Laid-Open No. 2016-164018 Summary of the Invention [Problem to be solved by the invention]

[0018] Until now, the lateral vibration that occurs in the last car of a railway vehicle has been controlled by control technologies such as active suspension, which actively suppresses vibration by applying control force using hydraulic or pneumatic actuators, but aerodynamic countermeasures have presented challenges. As an aerodynamic countermeasure, Patent Documents 1 and 2 show that vehicle vibration can be suppressed by installing vertical partitions under the floor of the vehicle.

[0019] An object of the present invention is to provide a vehicle vibration suppression structure that can suppress vibrations occurring in a vehicle by changing the shape of the lower part of the vehicle body. [Means for solving the problem]

[0020] The present invention solves the above problems by the means described below. Although the reference numerals corresponding to the embodiments of the present invention are given in parentheses, the present invention is not limited to these embodiments. The invention of claim 1 is a vehicle vibration suppression structure (10) that suppresses vibrations that occur in vehicles (3C; 3A to 3C) of a train (2) due to fluctuating aerodynamic forces that occur when the train (2) is running, as shown in Figures 1 to 4, and is characterized in that the distance (S) between the lower parts of both side body parts (9R, 9L) of the vehicle is narrower than the width (W) of the bottom part (8) of the vehicle body, and both edges of the bottom part of the vehicle body protrude outward beyond the lower parts of both side body parts.

[0021] The invention of claim 2 is a vehicle vibration suppression structure as described in claim 1, characterized in that the distance between both sides of the vehicle body gradually narrows toward the bottom of the vehicle body, as shown in Figures 2 and 3.

[0022] The invention of claim 3 is a vehicle vibration suppression structure as described in claim 1, characterized in that, as shown in Figures 2 and 3, the lower parts of both sides of the vehicle body are the lower parts of the wainscoting (9c) that constitute the side structure of the vehicle body (5).

[0023] The invention of claim 4 is a vehicle vibration suppression structure as described in claim 1, characterized in that, as shown in Figures 1 and 2, both edge portions of the bottom of the vehicle body protrude continuously in the longitudinal direction of the vehicle body.

[0024] The invention of claim 5 is a vehicle vibration suppression structure as described in claim 1, characterized in that both edges of the bottom of the body of the last vehicle (3C) of the train protrude, as shown in Figure 1.

[0025] The invention of claim 6 is a vehicle vibration suppression structure as described in claim 1, characterized in that both edges of the bottom of the body of all cars (3A to 3C) of the train protrude, as shown in Figure 4.

[0026] The invention of claim 7 is a vehicle vibration suppression structure as defined in claim 1, wherein when the protrusion amount of both edges of the bottom of the car body is zero, the increase amount of fluctuating aerodynamic force between the rearmost car and the car immediately preceding it, as determined by numerical simulation, is Δf1; when the protrusion amount of both edges of the bottom of the car body is Δw2, the increase amount of fluctuating aerodynamic force between the rearmost car and the car immediately preceding it, as determined by numerical simulation, is Δf2; and when the width of the bottom of the car body is W, the protrusion amount Δw of both edges of the bottom of the car body is determined based on the following prediction formula for the increase amount of fluctuating aerodynamic force Δf: This is a vehicle vibration suppression structure characterized by TIFF2026037592000002.tif23166. [Effects of the Invention]

[0027] According to the present invention, by changing the shape of the lower part of the vehicle body, it is possible to suppress shaking occurring in the vehicle. [Brief explanation of the drawings]

[0028] [Figure 1] 1 is a perspective view schematically showing a train equipped with a vehicle vibration suppression structure according to an embodiment of the present invention; [Figure 2] 1A and 1B are external views showing a vehicle equipped with a vehicle vibration suppression structure according to an embodiment of the present invention, with some parts omitted, where (A) is a perspective view, (B) is a side view, and (C) is a front view. [Figure 3] 1 is a front view that schematically shows a vehicle equipped with a vehicle vibration suppression structure according to an embodiment of the present invention; [Figure 4] FIG. 10 is a perspective view schematically showing a train equipped with a vehicle vibration suppression structure according to a second embodiment of the present invention. [Figure 5] 1A and 1B are external views of the rear end of a vehicle model of a basic shape that does not have a vehicle vibration suppression structure according to an embodiment of the present invention, where (A) is an oblique view, (B) is a side view, and (C) is a front view. [Figure 6]1A and 1B are external views of the rear end of a vehicle model having a side cutout shape and equipped with a vehicle vibration suppression structure according to an embodiment of the present invention, where (A) is an oblique view, (B) is a side view, and (C) is a front view. [Figure 7] FIG. 1 is a perspective view showing a computational domain and a computational grid for a numerical simulation. [Figure 8] This is a visualization of the serpentine flow that occurs under the car body floor. [Figure 9] 10 is a graph showing an increment in fluctuating aerodynamic force for each vehicle due to serpentine flow under the vehicle body floor. [Figure 10] 10 is a graph showing the increment of fluctuating aerodynamic forces due to serpentine flow under the body floor for each vehicle in the case of the basic shape and the side surface scraped shape. [Figure 11] These are distribution maps of the standard deviation of the pressure coefficients on the vehicle surface, where (A) is a distribution map of the standard deviation of the pressure coefficients on the front, side, top and bottom surfaces for the basic shape, and (B) is a distribution map of the standard deviation of the pressure coefficients on the front, side, top and bottom surfaces for the side-cut shape. [Figure 12] 1 is a conceptual diagram showing the relationship between the amount of shavings on the underside of the vehicle body and the increase in fluctuating aerodynamic force; (A) is a schematic diagram showing the basic shape and the side shaving shape superimposed on each other; (B) is a graph showing the increase in fluctuating aerodynamic force of the rearmost vehicle for the basic shape and the side shaving shape; (C) is a graph showing an example of the relationship between the increase in fluctuating aerodynamic force and the ratio of the shavings; and (D) is a simple prediction formula for the increase in fluctuating aerodynamic force due to the amount of shavings on the underside of the vehicle. [Figure 13] 1 is a graph showing an increase in pressure fluctuations in the last car of a train. DETAILED DESCRIPTION OF THE INVENTION

[0029] (First embodiment) A first embodiment of the present invention will be described in detail below with reference to the drawings. 1 and 3 is a track (passage) on which a train 2 runs. The track 1 is provided with a pair of rails 1a on the left and right sides that guide wheels 4a of the train 2.

[0030] The train 2 shown in FIG. 1 is a train made up of vehicles intended to operate on the track 1. The train 2 is made up of multiple vehicles traveling along the track 1, and is, for example, a passenger train for transporting passengers. The train 2 is a railway vehicle such as an electric train or a diesel railcar, and is, for example, a railway vehicle that runs on the Shinkansen (registered trademark) at a high speed of 320 km / h or more. The train 2 shown in FIG. 1 is made up of a total of six cars: a leading car 3A located at the front of the train, an intermediate car 3B located in the middle of the train 2, and a rear car (rear car) 3C that has the same shape as the leading car 3A and is located at the rear of the train 2. The train 2 includes a bogie 4 shown in FIGS. 2 and 3 and a carbody 5 shown in FIGS. 1 to 3. The bogie 4 shown in FIGS. 2 and 3 is a running device (traveling device) that supports the carbody 5 and runs on the track 1. The bogie 4 includes wheels 4a that are in rolling contact with the rails 1a. The following description will focus on the rear car 3C shown in FIGS. 1 to 3.

[0031] The car body 5 shown in Figures 1 to 3 is a structure for loading and transporting passengers or cargo. The car body 5 is composed of outer plates, which are the outer plate portions of the structure of the car body 5, and a framework, which is the main member of the structure of the car body 5. The car body 5 has a stretched shell structure in which the strength is provided by the outer plates and framework made of stainless steel or aluminum alloy. The car body 5 is a widened car body with a tapered bottom structure in which the bottoms of both side sections 9R, 9L of the car body are tapered toward the inside of the car body 5. The car body 5 has a car body end (front car body) 6 shown in Figure 2, and an upper car body 7, a car body bottom 8, and both side car body sections 9R, 9L shown in Figures 2 and 3. As shown in Figure 3, the car body 5 has wide gaps between the upper and central parts of both side sections 9R, 9L of the car body to ensure sufficient volume inside the passenger compartment, without exceeding the vehicle clearance, and the lower wainscoting 9c of both side sections 9R, 9L of the car body is inclined so as to narrow inward toward the car body bottom 8. Here, the vehicle clearance refers to the vertical and horizontal limits that the outline of the cross-sectional shape of the car must not exceed when the car is stationary on a straight or curved track.

[0032] The carbody end 6 shown in FIG. 2 is an outer plate (end plate) that constitutes the end structure (front body structure) of the carbody 5. The carbody end 6 is the front end of the lead car 3A and the rear end of the rearmost car 3C, and is formed in a long, streamlined shape with smoothly curved surfaces to reduce air resistance, etc. The carbody upper part 7 shown in FIGS. 2 and 3 is an outer plate (roof plate) that constitutes the roof structure (roof body structure) of the carbody 5. The carbody upper part 7 is equipped with a current collector for conducting power from the contact wires of the overhead line to the car, and is formed with smoothly curved surfaces to reduce air resistance, etc. The carbody bottom 8 is an underframe or outer plate that constitutes the floor structure (floor structure) of the carbody 5. As shown in FIGS. 2 and 3, both edges of the carbody bottom 8 protrude outward beyond the lower parts of the carbody side parts 9R, 9L. The carbody bottom 8 is formed into a flat surface. The bogie 4 is disposed in a recess formed in the bottom of the car body 8, and both sides of the recess are covered by a bogie cover that is flush with the wainscoting 9c.

[0033] The carbody side sections 9R, 9L shown in Figures 2 and 3 are outer panels (side panels) that make up the side structure (side structure) of the carbody 5. The carbody side sections 9R, 9L include, for example, side windows attached to the carbody side sections 9R, 9L, side entrances used by crew members when boarding and disembarking, and side entrances used by passengers when boarding and disembarking. As shown in Figure 3, the distance S between the lower parts of the carbody side sections 9R, 9L is narrower than the width W of the carbody bottom 8. The carbody side sections 9R, 9L are formed so that the distance S between the carbody side sections 9R, 9L gradually narrows toward the carbody bottom 8. As shown in Figures 2 and 3, the carbody side sections 9R, 9L include a fascia panel 9a, a siding panel 9b, a wainscot panel 9c, and a lower edge section 9d.

[0034] The fascia board 9a shown in Figures 2 and 3 is an outer panel that forms the upper side structure of both side body sections 9R, 9L. The fascia board 9a forms the portion above the side windows of both side body sections 9R, 9L, and is formed approximately perpendicular to the car body bottom section 8. The siding 9b is an outer panel that forms the side structure between the fascia board 9a and the waist panel 9c. The siding 9b is formed on the same plane as the fascia board 9a between multiple side windows, between the side windows and the side entrances, and between the side entrances and the end face of the car body, and is formed approximately perpendicular to the car body bottom section 8.

[0035] The wainscots 9c are outer panels that form the lower side structure of both side body sections 9R and 9L. As shown in FIG. 3, the pair of left and right wainscots 9c are formed as flat surfaces that taper toward the inside of the car body 5. The wainscots 9c form the portions of both side body sections 9R and 9L below the side windows and are formed at an angle to the fascia boards 9a and the apron 9b. The wainscots 9c reduce the effects of pressure fluctuations that occur on both side body sections 9R and 9L when meandering air flows upward by forming a space between the outer surface of the wainscots 9c and the upper surface of the car body bottom 8. The lower edge 9d is the portion where the pair of left and right wainscots 9c and the upper surface of the car body bottom 8 are joined. As shown in FIG. 3, the lower edge 9d connects the outer surface of the wainscots 9c to the upper surface of the car body bottom 8 with a smoothly curved surface.

[0036] The vibration suppression structure 10 shown in Figures 1 to 3 is a structure that suppresses vibrations that occur in the last car 3C due to fluctuating aerodynamic forces that are generated when the train 2 is traveling. Here, fluctuating aerodynamic forces are forces that vary over time and are generated on an object due to airflow. The vibration suppression structure 10 reduces pressure fluctuations that occur when a serpentine flow that occurs between the bottom 8 of the carbody of the train 2 and the track 1 as the train 2 travels is rolled up on both sides 9R, 9L of the carbody of the last car 3C, thereby suppressing vibrations that occur in the last car 3C. The vibration suppression structure 10 has a protrusion 11 shown in Figures 1 to 3.

[0037] The protrusions 11 shown in FIGS. 1 to 3 are portions that change the direction of serpentine flow that rolls up onto both side body portions 9R, 9L. As shown in FIG. 3, the protrusions 11 protrude outward beyond the lower portions of both side body portions 9R, 9L and are formed integrally with the carbody bottom portion 8. As shown in FIGS. 1 and 2, the protrusions 11 are formed continuously in the length direction of the carbody 5 from the front end to the rear end of the last car 3C. As shown in FIG. 1, the protrusions 11 are formed on both edges of the carbody bottom portion 8 of the last car 3C of the train 2 and are formed continuously along the length direction of both side body portions 9R, 9L of the last car 3C of the train 2. The protrusions 11 function as fins that prevent serpentine flow that occurs between the track 1 and the carbody bottom portion 8 when the train 2 is running from rolling up onto both side body portions 9R, 9L of the last car 3C. The protrusion 11 is a plate-shaped portion whose tip (edge) is rounded to reduce air resistance. As shown in Fig. 3, the protrusion 11 is formed with a predetermined protrusion amount Δw within a range that does not exceed the vehicle limit.

[0038] The amount of protrusion Δw is determined, for example, based on a prediction formula for the increase Δf in fluctuating aerodynamic force, as shown in the following equation 1. The amount of protrusion Δw is set to a value that minimizes the increase Δf in fluctuating aerodynamic force between the rearmost vehicle 3C and the intermediate vehicle 3B immediately preceding this rearmost vehicle 3C, calculated by numerical simulation.

[0039]

number

[0040] Here, Δf1 in Equation 1 is the increase in fluctuating aerodynamic force between the rearmost vehicle 3C and the immediately preceding intermediate vehicle 3B, as determined by numerical simulation, when the amount of protrusion Δw of both edges of the body bottom 8 of the rearmost vehicle 3C is 0. Δf2 is the increase in fluctuating aerodynamic force between the rearmost vehicle 3C and the immediately preceding intermediate vehicle 3B, as determined by numerical simulation, when the amount of protrusion Δw2 of both edges of the body bottom 8 of the rearmost vehicle 3C is Δw2. W is the width of the body bottom 8 of the rearmost vehicle 3C.

[0041] Next, the operation of the vehicle vibration suppression structure according to the first embodiment of the present invention will be described. When train 2 travels through a lighted section other than a tunnel section, a serpentine flow (air turbulence) occurs between track 1 and the bottom of the car body 8, and the serpentine flow spreads as it moves toward the last car 3C. When this serpentine flow is rolled up on both sides 9R, 9L of the car body of the last car 3C of train 2, the pressure fluctuates greatly on both sides 9R, 9L of the car body of the last car 3C. As a result, large pressure fluctuations occur on both sides 9R, 9L of the car body of the last car 3C, and these large pressure fluctuations generate fluctuating aerodynamic forces that cause the last car 3C to sway left and right.

[0042] As shown in Figures 1 to 3, when the rearmost car 3C is equipped with the vibration suppression structure 10, the protrusions 11 protrude from below the carbody side sections 9R, 9L, forming a space between the outer side of the wainscoting 9c of the carbody side sections 9R, 9L and the upper side of the protrusions 11. As a result, the protrusions 11 change the direction of the serpentine airflow that rolls up on the carbody side sections 9R, 9L, away from the carbody side sections 9R, 9L. In addition, the space formed between the outer side of the wainscoting 9c and the upper side of the protrusions 11 reduces the impact of pressure fluctuations that occur on the carbody side sections 9R, 9L when the serpentine airflow rolls up. As a result, the fluctuating aerodynamic forces acting on the carbody 5 are reduced, and vibrations occurring in the carbody 5 are suppressed.

[0043] The vehicle vibration suppression structure according to the first embodiment of the present invention has the following effects. (1) In this first embodiment, the distance S between the lower parts of both side body portions 9R, 9L is narrower than the width W of the car body bottom 8, and both edges of the car body bottom 8 protrude outward beyond the lower parts of both side body portions 9R, 9L. Therefore, the direction of the serpentine airflow rolling up toward both side body portions 9R, 9L can be easily changed by both edges of the car body bottom 8. As a result, pressure fluctuations at both side body portions 9R, 9L that occur when the serpentine airflow rolls up toward both side body portions 9R, 9L are reduced, and shaking that occurs in the rearmost car 3C can be suppressed.

[0044] (2) In the first embodiment, the distance S between the vehicle body side portions 9R, 9L gradually narrows toward the vehicle body bottom portion 8. This allows a space to be formed between the edges of the vehicle body bottom portion 8 and the lower portions of the vehicle body side portions 9R, 9L. As a result, the effects of pressure fluctuations that the vehicle body side portions 9R, 9L experience when the vehicle body is rolled up onto the vehicle body side portions 9R, 9L can be reduced, and the fluctuating aerodynamic forces acting on the vehicle body side portions 9R, 9L can be reduced.

[0045] (3) In this first embodiment, the lower parts of both side body parts 9R, 9L are the lower parts of the side wainscoting 9c of the car body 5. For this reason, for example, by leaving the width of the floor of the rearmost car unchanged and making the car body side above the floor narrower than the width of the floor, it is possible to suppress the swaying of the rearmost car 3C by simply changing the shape of the lower part of the car body 5 so as to leave a horizontal plate-like portion under the floor.

[0046] (4) In this first embodiment, both edges of the carbody bottom 8 protrude continuously in the length direction of the carbody 5. Therefore, by changing the shape of the lower part of the carbody 5 without exceeding the vehicle clearance, it is possible to suppress the sway of the rearmost car 3C with a simple structure without changing any new parts or mechanisms.

[0047] (5) In the first embodiment, both edges of the car body bottom 8 of the last car 3C of the train 2 protrude. This reduces the shaking of the car body 5, which is particularly large in the last car 3C.

[0048] (Second embodiment) In the following, the same parts as those shown in FIGS. 1 to 3 are denoted by the same reference numerals and detailed description thereof will be omitted. The vibration suppression structure 10 shown in Fig. 4 suppresses vibrations that occur in the intermediate car 3B and the last car 3C due to fluctuating aerodynamic forces that occur when the train 2 is traveling. The vibration suppression structure 10 reduces pressure fluctuations that occur when the serpentine flow that occurs between the bottom 8 of the carbody of the train 2 and the track 1 as the train 2 travels on the track 1 is rolled up onto both side carbody portions 9R, 9L of the intermediate car 3B and the last car 3C, thereby suppressing vibrations that occur in the intermediate car 3B and the last car 3C. Unlike the protrusion 11 shown in Fig. 1, the protrusion 11 shown in Fig. 4 is formed continuously along the length direction of both side carbody portions 9R, 9L of all of the leading car 3A, intermediate car 3B, and last car 3C that make up the train 2.

[0049] The vehicle vibration suppression structure according to the second embodiment has the following advantages in addition to the advantages of the first embodiment. In this second embodiment, both edges of the carbody bottom 8 of all cars of the train 2 protrude. This reduces the fluctuating aerodynamic force acting not only on the rearmost car 3C but also on the middle car 3B, thereby suppressing the shaking of the middle car 3B. [Example]

[0050] Next, an embodiment of the present invention will be described. To investigate the effect of the serpentine flow under the floor of a railway vehicle on the fluctuating aerodynamic forces acting on the last vehicle, we conducted an LES (Large-eddy simulation) analysis using a vehicle model of actual shape, simulating running conditions under lighting conditions. Numerical simulations were conducted for the last vehicle with the basic shape shown in Fig. 5 (Example) and the last vehicle with the side-cut shape shown in Fig. 6 (Comparative Example) using the calculation space shown in Fig. 7. We confirmed the reduction in fluctuating aerodynamic forces acting on the vehicle when the basic shape shown in Fig. 5 was changed to the side-cut shape shown in Fig. 6.

[0051] (Computational model) The basic shape shown in Fig. 5 is the shape of the rearmost car of the actual shape vehicle model used in the calculations in the numerical simulation. The basic shape vehicle was a six-car train model based on a 1 / 8.4 scale vehicle model for conventional lines used in wind tunnel experiments in the Railway Technical Research Institute's large-scale low-noise wind tunnel. The basic shape is a bogie shape in which the bogie is placed in a recess in the bottom of the car body, just like the actual shape vehicle, and both sides of this recess are covered by bogie covers.

[0052] The side cut shape shown in Figure 6 corresponds to the rearmost vehicle 3C shown in Figures 1 to 4, and is the shape of the rearmost vehicle of the actual vehicle model used in the numerical simulation. The side cut shape is the same width as the floor of the basic shape shown in Figure 5, and is a shape in which a portion of the lower part of the vehicle side has been cut away, leaving the floor of the basic shape. The side cut shape has a larger inclination angle of the parts corresponding to the wainscoting 9c of both side body parts 9R and 9L shown in Figure 3 than the inclination angle of the parts corresponding to the wainscoting 9c of both side body parts 9R and 9L of the basic shape. The side cut shape differs from the car body bottom part 8 of the basic shape, in that the parts corresponding to both edges of the car body bottom part 8 shown in Figure 3 protrude from below both side body parts 9R and 9L.

[0053] Figure 7 is a perspective view showing the computational domain and computational grid for the numerical simulation. The computational domain (5m x 3m) for the cross section perpendicular to the main flow (inflow / outflow boundary) was equal to the cross-sectional dimensions of the enclosed measurement section in the wind tunnel experiment, with the area in the main flow direction extended. A moving ground plate used in the wind tunnel experiment was simulated, and a train speed of 54km / h was applied to the floor, and calculations were carried out under conditions simulating running conditions for evaluation. The influence of the presence or absence of rails was deemed small, so rails were omitted from the computational model.

[0054] (Meandering flow under the floor) Figure 8 shows the visualization results of the instantaneous field distribution of the x-direction flow velocity under the vehicle floor. Calculations for the basic shape shown in Figure 5 and the side-cut shape shown in Figure 6 were carried out under the condition of serpentine flow. As a result, as shown in Figure 8, negative pressure was generated near the position where the x-direction flow velocity under the vehicle floor flows from the center of the vehicle width to the side, and it was confirmed that the underfloor serpentine flow was fully developed in the rearmost car, and that the rearmost car was affected by the underfloor serpentine flow.

[0055] Fig. 9 shows the aerodynamic force F y 9 is a graph showing the results of calculating the standard deviation (SD) (fluctuating aerodynamic force) of each of the vehicles car1 to car6 for both the basic shape and the smoothed shape. The vertical axis shown in FIG. 9 represents the aerodynamic force F in the y direction (left-right direction of the vehicle body) acting on the body of each of the vehicles car1 to car6. y The horizontal axis represents each car in the six-car train. Here, the smooth shape is the basic shape shown in Figure 5, with no bogies, but with the basic shape's carbody bottom smoothed. The increments shown in Figure 9 are the increments in fluctuating aerodynamic forces of the last car, car6, due to underfloor serpentine flow in the basic and smooth shapes. As shown in Figure 9, the fluctuating aerodynamic forces are greatest in the last car, car6, and it was confirmed that the increase in the basic shape is greater than that in the smooth shape.

[0056] (Effect of side grinding) Figure 10 is a graph showing the results of calculating the fluctuating aerodynamic forces in the lateral direction for each of cars car1 to car6 in the open section, for both the basic shape and the shape with the side surfaces trimmed. The vertical axis in Figure 10 represents the fluctuating aerodynamic forces in the y direction acting on the body of each of cars car1 to car6, and the horizontal axis represents each car in the six-car train. As shown in Figure 10, it was confirmed that trimming a portion of the lower side of the rearmost car, car6, reduced the increase in fluctuating aerodynamic forces.

[0057] Figure 11 shows the pressure coefficient C of the vehicle surface for the basic shape and the side-cut shape. p 11(A) is a distribution diagram of the standard deviation SD of the pressure coefficient C p The standard deviation SD of the axial force is significantly reduced. This reduces the force acting in the lateral direction, and it was confirmed that the fluctuating aerodynamic force is reduced.

[0058] FIG. 12 is a conceptual diagram showing the relationship between the amount of cutting of the undercarriage and the increase in fluctuating aerodynamic force. Δf1 shown in FIGS. 12(B) and 12(C) is the increase in fluctuating aerodynamic force applied to the fifth and sixth cars of the basic configuration. Δf2 is the increase in fluctuating aerodynamic force applied to the fifth and sixth cars of the side-cut configuration. W shown in FIGS. 12(A) and 12(D) is the width of the underfloor (the width of the carbody bottom 8 shown in FIG. 3). Δw1 is the amount of cutting (=0) for the basic configuration. Δw2 is the amount of cutting (protrusion amount shown in FIG. 3) for the side-cut configuration. As shown in the simplified prediction formula for the increase in fluctuating aerodynamic force shown in FIG. 12(D), lateral shaking of the carbody 5 can be suppressed by setting the amount of cutting (protrusion amount) Δw that minimizes the increase in fluctuating aerodynamic force Δf.

[0059] (Other embodiments) The present invention is not limited to the above-described embodiment, and various modifications and alterations are possible as described below, and these are also within the scope of the present invention. (1) In this embodiment, the train 2 is made up of Shinkansen cars, but the present invention can also be applied to trains made up of cars for Shinkansen-conventional line through-running that can run on both Shinkansen and conventional lines. Also, in this embodiment, the train 2 is made up of six cars, but the present invention can also be applied to trains with five or fewer cars or seven or more cars. Furthermore, in this embodiment, the wainscoting 9c is made up of a flat, inclined surface, but the present invention can also be applied to trains with a concave or convex curved surface.

[0060] (2) In this embodiment, the description has been given of an example of a tapered bottom structure in which the distance S between the both side body portions 9R, 9L is narrowest at the lower edge portions 9d of the both side body portions 9R, 9L. However, the present invention can also be applied to a tapered bottom structure in which the lower portions of the both side body portions 9R, 9L are tapered toward the inside of the both side body portions 9R, 9L. In addition, in this embodiment, the description has been given of an example of a vehicle body 5 having a tapered bottom structure in which the lower portions of the both side body portions 9R, 9L are tapered toward the inside of the both side body portions 9R, 9L. However, the present invention can also be applied to a vehicle structure in which the both side body portions 9R, 9L are perpendicular to the vehicle body bottom 8 and the lower portions of the both side body portions 9R, 9L are not tapered toward the inside of the vehicle body 5. For example, the present invention can also be applied to a vehicle structure in which the both side body portions 9R, 9L are perpendicular to the vehicle body bottom 8 and both side portions of the vehicle body bottom 8 are extended to the vehicle limit. Furthermore, in the first embodiment, an example has been described in which the protrusion 11 is installed on the last car 3C of the train 2 traveling in the D1 direction from the starting station to the terminal station, but the installation target of the protrusion 11 is not limited to only the last car 3C. For example, when the train 2 turns around at the terminal station and travels from the terminal station to the starting station in the D2 direction, which is the opposite direction to the D1 direction, the present invention can also be applied to a case in which the protrusion 11 is installed on the leading car 3A and the last car 3C. [Explanation of symbols]

[0061] 1 track 1a rail 2 trains 3A Leading car (car) 3B Intermediate car (car) 3C Last car (car) 4 carts 4a wheels 5. Body 6. Vehicle end 7 Upper body 8 Bottom of the vehicle 9R, 9L both sides of the vehicle 9a Backboard 9b Fukiyose 9c wainscot 10. Vibration suppression structure 11 Protrusion D1, D2 direction W width S interval Δw Protrusion (cutting amount)

Claims

1. A vehicle vibration suppression structure that suppresses vibrations that occur in a vehicle of a train due to fluctuating aerodynamic forces that occur when the train is running, The distance between the lower portions of both sides of the vehicle body is narrower than the width of the bottom of the vehicle body, Both edges of the bottom of the vehicle body protrude outward beyond the lower portions of both side portions of the vehicle body. A vehicle vibration suppression structure characterized by the above.

2. 2. The vehicle vibration suppression structure according to claim 1, The distance between the two sides of the vehicle body gradually narrows toward the bottom of the vehicle body. A vehicle vibration suppression structure characterized by the above.

3. 2. The vehicle vibration suppression structure according to claim 1, The lower portions of both sides of the vehicle body are lower portions of wainscots that constitute the side structure of the vehicle body, A vehicle vibration suppression structure characterized by the above.

4. 2. The vehicle vibration suppression structure according to claim 1, Both edge portions of the vehicle body bottom portion protrude continuously in the longitudinal direction of the vehicle body; A vehicle vibration suppression structure characterized by the above.

5. 2. The vehicle vibration suppression structure according to claim 1, Both edges of the bottom of the body of the last car of the train protrude. A vehicle vibration suppression structure characterized by the above.

6. 2. The vehicle vibration suppression structure according to claim 1, Both edges of the bottom of the body of all cars of the train are protruding; A vehicle vibration suppression structure characterized by the above.

7. 2. The vehicle vibration suppression structure according to claim 1, When the protrusion amount of both edges of the bottom of the vehicle body is zero, the increase in the fluctuating aerodynamic force Δf between the rearmost vehicle and the vehicle immediately preceding it, as determined by numerical simulation, is １ and The protrusion amount Δw of both edges of the bottom of the vehicle body ２ When the vehicle is in a state where ... ２ and When the width W of the bottom of the vehicle body is The protrusion amount Δw of both edge portions of the bottom of the vehicle body is determined based on the following prediction formula for the increase amount Δf of fluctuating aerodynamic force: A vehicle vibration suppression structure characterized by the above.

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