BACKGROUND OF THE INVENTION
1. Field of the Invention
[0001] The present invention relates to a rail guard support structure of a railway vehicle
such as a bullet train, and specially to such a rail guard support structure according
to the preamble of claim 1.
2. Related Art
[0002] EP 1 251 054 A2 discloses a rail guard support structure according to the preamble of claim 1.
[0003] Generally, in a railway vehicle, a rail guard device is mounted at a front portion
of a vehicle to eliminate obstacles (e.g., obstacles with weight of about 100 kg or
less) on a track so as to be moved off the track. In order to minimize damage to a
vehicle body when the rail guard device moves the obstacles off the track, it is desired
that the rail guard device be hardly affected by collision energy in collision. To
this end, typically, a component that is hardly deformed is provided at the front
portion of the vehicle and is connected to the vehicle body through an impact absorber.
[0004] Figs. 7 and 8 show an example of the conventional rail guard support structure in
which an impact absorbing plate 102 comprised of a plurality of plate springs 102a
superposed to have a spacing equal to a plate thickness is provided behind and in
conformity to a steel rail guard 101 that is curved to project forwardly in a direction
in which the vehicle travels. In this support structure, the impact absorbing plate
102 is intended to absorb energy which remains unabsorbed as a result of deformation
of the rail guard 101. The impact absorbing plate 102 is mounted to a vehicle body
frame 105 (see Fig. 7) by means of an impact absorbing plate support device 103 and
a mounting bracket 104. The rail guard 101 is mounted at right and left side portions
to the vehicle body frame 105 through mounting brackets 106. Reference numeral 107
denotes a lug member for preventing falling of the rail guard 101.
[0005] In this structure, to deal with collision energy that increases with an increasing
speed of the vehicle, a required plate thickness correspondingly increases. So, the
rail guard 101 is comprised of a steel plate thicker than the vehicle body frame 105.
For this reason, in collision with an obstacle, the rail guard 101 is hardly deformed,
thereby causing a large collision load to be applied on the vehicle body.
[0006] As a solution to this,
Japanese Laid-Open Patent Application Publication No. Hei. 2001 - 55141 discloses a lightweight rail guard device intended to enhance a function of moving
obstacles off the track and minimize a collision load applied on a vehicle body. This
rail guard device is structured such that both sides of a steel rail guard curved
to project forwardly in the traveling direction are connected by means of a cross
beam and a hollow member made of aluminum alloy is provided between the rail guard
and the cross beam on a center line of the rail guard.
[0007] Since the role of the rail guard device is to eliminate obstacles on the track as
described above, its rail guard (front end skirt) is firmly fixed to the cross beam
of the vehicle body frame. This greatly increases strength of the front portion of
the vehicle body. Therefore, when vehicles having such rail guard device actually
collide with each other, impact generated in collision is tremendous. In some cases,
a driver's cabin located behind the rail guard device at the front portion of the
vehicle body might crush before the front portion of the vehicle body crushes. The
crashworthiness of the vehicle having such a rail guard is poor, and this is undesirable
to a driver and passengers. As used herein, the "crashworthiness" means that a survival
zone for the driver and passengers is ensured and impact on them is relieved.
SUMMARY OF THE INVENTION
[0008] The present invention has been made under the circumstances, and an object of the
present invention is to provide a rail guard support structure capable of sufficiently
resisting collision.
[0009] This object is achieved by a rail guard support structure according to claim 1
[0010] According to the present invention, there is provided a rail guard support structure
of a railway vehicle by which a rail guard for eliminating an obstacle on a track
during traveling of the vehicle is supported by a vehicle body frame, wherein
- an energy absorbing element is provided behind the front portion of the rail guard
to extend in the longitudinal direction of the vehicle, and a rear end portion of
the energy absorbing element is attached to the vehicle body frame by means of an
energy absorbing element support device,
- upper edge portions of latter half parts of right and left side portions of the rail
guard are supported by the vehicle body frame at locations lateral of the energy absorbing
element support device; and
- right and left side portions of the rail guard which is supported by the vehicle body
frame substantially conform in location to the rear end portion of the energy absorbing
element in the longitudinal direction of the vehicle.
[0011] As the energy absorbing element, well-known energy absorbing elements with a low
peak load and a high mean reaction force, for example, a pipe member that is tubular
with rectangular cross-section, may be used.
[0012] On assumption that railway vehicles collide with each other, a length of the crush
zone at the front portion of the vehicle body is designed in view of various factors
associated with collision. With the above construction, within the crush zone, a rigid
member for supporting the rail guard is not provided, and therefore, the rail guard
is not rigidly attached to the vehicle body frame. As a result, a peak load in crush
within the crush zone is suppressed.
[0013] Since the energy absorbing element with a low peak load and a high mean reaction
force is provided behind the front portion of the rail guard to extend in the longitudinal
direction of the vehicle, the collision energy is also absorbed by the energy absorbing
element. In contrast to the structure without the energy absorbing element, the ability
to absorb the collision energy is higher and impact acting on driver and passengers
is relieved. Further, since the energy absorbing element absorbs large part of the
collision energy generated in eliminating the obstacles, which is to be absorbed by
the rail guard device, impact generated in eliminating the obstacles is relieved.
[0014] Therefore, when large collision energy is applied on the rail guard by moving obstacles
off the track during traveling of the vehicle, such collision energy is absorbed by
the energy absorbing element and impact applied on the driver and passenger is relieved.
[0015] It is preferable that the upper edge portions of the right and left side portions
of the rail guard are attached to the vehicle body frame by means of a rail guard
support device at a location forward of a driver's cabin.
[0016] Since the survival zone for the driver and passengers, including the drive's cabin,
is located behind the crush zone, crush of the driver's cabin is avoided in collision
and the survival zone for the driver and passengers is ensured. More specifically,
the collision energy is absorbed by the energy absorbing element within the crush
zone located forward of and apart from the driver's cabin. As a result, the survival
zone for the driver and passengers is ensured and impact acting on them is relieved.
[0017] It is preferable that the rail guard is obliquely downwardly inclined forwardly or
laterally, a block that is of a substantially rectangular parallelepiped shape is
attached to a vicinity of an upper edge portion of the front portion of the rail guard,
and a lower edge portion of the front portion of the rail guard is located substantially
vertically below a front face of the block.
[0018] With this construction, since the block of the substantially rectangular parallelepiped
shape is attached to the vicinity of the upper edge portion of the front portion of
the rail guard and the lower edge portion of the front portion of the rail guard is
located substantially vertically below the front face of the block, the upper-side
portion (block) of the rail guard and the lower-side portion of the rail guard collide
simultaneously in collision between vehicles. Therefore, the vertical load generated
by a rake angle of the rail guard is reduced and crush and deformation of the rail
guard occurs in the longitudinal direction of the vehicle.
[0019] The above and further objects and features of the invention will more fully be apparent
from the following detailed description with accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020]
Fig. 1 is a side view showing a rail guard support structure of a railway vehicle
according to the present invention;
Fig. 2 is a plan view of Fig. 1;
Figs. 3(a) to 3(d) are schematic views showing simulation analysis results of deformation
of a rail guard having the structure of the present invention, which deformation is
caused by a collision load generated by colliding a rigid body ball of 100kg mass
with the center of the rail guard at a speed of 300 km/h;
Fig. 4 is a view showing a reaction force as a function of time of a rail guard device
(rail guard) in the direction in which the vehicle travels, which change is caused
by colliding the rigid body ball of 100kg mass with the rail guard device having the
rail guard support structure of the present invention from its front toward its center;
Figs. 5(a) to 5(c) are schematic views showing a result of simulation analysis of
deformation of the rail guard having the structure of the present invention, which
deformation is caused by a collision load generated by colliding the rail guard with
the rigid body ball of 100kg mass at a speed of 300 km/h deviating from the center
of the rail guard;
Figs. 6(a) to 6(d) are views showing a result of simulation analysis of deformation
of a vehicle body having the structure of the present invention, which deformation
is caused by colliding a rigid wall with the vehicle body;
Fig. 7 is a side view showing the conventional rail guard support structure of a railway
vehicle; and
Fig. 8 is a plan view of Fig. 7.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0021] Hereinafter, an embodiment of the present invention will be described with reference
to the accompanying drawings.
[0022] Referring now to Figs. 1 and 2, a rail guard 1 for eliminating obstacles on a track
during traveling of a vehicle is bent like horseshoe to be entirely curved to project
forwardly and is comprised of a front portion 1A and right and left side portions
1B and 1C extending rearwardly from right and left ends of the front portion 1A. The
rail guard 1 is suspended from a vehicle body frame 10 by means of a rail guard support
device 22 having a plurality of rail guard fitting members 2 and an upper support
member 3. That is, the front portion 1A of the rail guard 1 is not directly supported
by the vehicle body frame 10. More specifically, behind a crush zone S, upper edge
portions of the right and left side portions 1B and 1 C of the rail guard 1 are fixed
to the upper support member 3 by means of the plurality of fitting members 2. The
upper support member 3 is attached to the vehicle body frame 10. The vehicle body
structure within the crush zone S is designed to absorb collision energy by plastic
deformation.
[0023] A coupling bracket 4 protrudes rearwardly from the rear side of the front portion
1A of the rail guard 1. The coupling bracket 4 is coupled to a front end portion of
an energy absorbing pipe member 5 that is tubular with rectangular cross-section as
an energy absorbing element extending in the longitudinal direction of the vehicle
body. Unlike the conventional structure, behind the rail guard 1, there is no impact
absorbing plate comprised of a plurality of superposed plate springs and provided
so as to conform to the rail guard 1. The energy absorbing pipe member 5 extends along
a center axis of the vehicle. The energy absorbing pipe member 5 has a cutout portion
5a formed in an upper surface of the vicinity of a front end thereof to open upwardly
and to be laterally symmetric with respect to the center axis of the vehicle. The
front end portion of the energy absorbing pipe member 5 provided with the cutout portion
5a functions as a trigger portion that triggers bellows-like deformation of the energy
absorbing pipe member 5 to absorb energy. The use of the energy absorbing pipe member
5 that is tubular with rectangular cross-section instead of the conventional impact
absorbing plate 5 is advantageous in reducing weight.
[0024] A plurality of energy absorbing pipe members 5 may be provided. In that case, it
is preferable that the plurality of pipe members 5 are laterally symmetric with respect
to the center axis of the vehicle. This is because, upon impact in the center axis
direction of the vehicle acting on the front end portion of the rail guard 1, the
load acts on the respective energy absorbing pipe members (energy absorbing elements)
properly in balance, and therefore, the energy absorbing pipe members absorb the energy
by the bellows-like deformation without turning over.
[0025] A rear end portion of the energy absorbing pipe member 5 is connected to a lower
support member 6 extending in the lateral direction of the vehicle body. The lower
support member 6 is a closed box-like member. Right and left end portions of the lower
support member 6 are connected to lower end portions of the right and left support
members 7L and 7R vertically extending. Upper end portions of the right and left support
members 7L and 7R are fastened to the vehicle body frame 10 behind the crush zone
S. The lower support member 6 is connected to the vehicle body frame 10 by means of
right and left inclined support members 8L and 8R located behind the lower support
member 6 and extending rearwardly and obliquely upwardly. Thus, the support members
6, 7L, 7R, 8L and 8R constitute an energy absorbing element support device 21 for
supporting the rear end portion of the energy absorbing pipe member 5.
[0026] As described above, the upper edge portions of the right and left side portions 1B
and 1C of the rail guard 1 are supported by the vehicle body frame 10 by means of
the rail guard support device 22 (comprised of the rail guard fitting members 2 and
the upper support member 3) at positions lateral of the energy absorbing element support
device 21. Therefore, the upper edge portions of the right and left side portions
1B and 1 C of the rail guard 1 are attached to the vehicle body frame 10 by means
of the rail guard support device 22 at a location forward of the driver's cabin 13
located behind the crush zone S.
[0027] Since the energy absorbing pipe member 5 is located behind the rail guard 1 and the
rear end portion of the pipe member 5 is connected to the energy absorbing element
support device 21 (support members 6, 7L, 7R, 8L, and 8R) attached to the vehicle
body frame 10, a deformation stroke for absorbing collision energy becomes sufficiently
long. In addition, the rail guard 1 is supported by means of the rail guard support
device 22 (support members 2 and 3) behind the crush zone S. This eliminates a need
for a support device rigidly supporting the rail guard within the crush zone S. That
is, the rail guard is not rigidly mounted. As a result, a peak load in collision is
suppressed and the crashworthiness of the vehicle is improved.
[0028] In particular, since the survival zone for driver and passengers including the driver's
cabin 13 is located behind the crush zone S, crush of the driver's cabin 13 is prevented
in collision and the survival zone for the driver and passengers is ensured. Since
the collision energy is absorbed by the collision energy absorbing pipe member 5 within
the crush zone S located forward of and apart from the driver's cabin 13, the survival
zone for the drive and passengers is ensured and impact acting on the driver and passengers
is relieved.
[0029] As shown in Fig. 1, the rail guard 1 is obliquely downwardly inclined forwardly or
laterally. A block 9 that is of a substantially rectangular parallelepiped shape is
attached to a vicinity of the upper edge portion of the front portion of the rail
guard 1. A lower edge portion of the front portion of the rail guard 1 is located
vertically below a front face of the block 9. The front face of the block 9 is flat
within a substantially vertical plane and a rear face thereof is inclined so as to
conform to the rail guard 1. With this construction, when vehicles collide with each
other, an upper-side portion of the rail guard 1 (front face of the block 9) and a
lower-side portion of the rail guard 1 (lower edge portion of the rail guard 1) collide
simultaneously. As a result, a vertical load generated by a rake angle (angle with
respect to a vertical plane) of the rail guard 1 is reduced, and crush and deformation
of the rail guard 1 occurs in the longitudinal direction of the vehicle.
[0030] During traveling of the vehicle, when large collision energy acts on the rail guard
1 by eliminating the obstacles on the track, the rail guard 1 crushes to absorb collision
energy and the energy absorbing pipe member 5 is deformed like bellows to absorb the
collision energy. Therefore, an effect of absorbing the collision energy is equal
to or higher than that of the conventional structure (structure comprising the impact
absorbing plate having a plurality of plate springs superposed and provided behind
and in conformity to the rail guard).
[0031] Figs. 3(a) to 3(d) show simulation results of deformation of the rail guard having
the above-mentioned rail guard support structure, which deformation is caused by a
collision load generated when a rigid body ball of 100kg mass collides with the center
of the rail guard at a speed of 300km/h. Fig. 4 shows the resulting reaction force
of the rail guard (rail guard device). Figs. 3(a) to 3(d) show deformations occurring
when elapse time T after the collision is 0sec, 0.006sec, 0.012sec, and 0.03sec.
[0032] As can be sheen from Figs. 3(a) to 3(d) and Fig. 4, when the rigid body ball of 100
kg mass collides with the rail guard at a speed of 300km/h from its front toward its
center, the collision energy is absorbed and reduced by deformation of the rail guard
and the bellows-like deformation of the energy absorbing pipe member within the crush
zone S for 0.03 second after the collision. As can be seen from the graph in Fig.
4, from T = 0 second to T = 0.03 second, the reaction force of the rail guard (rail
guard device) in the direction in which the vehicle travels is smaller than 80tonf
and therefore, a peak load in collision is not so large.
[0033] In the same manner, Figs. 5(a) to 5(c) show deformation of the rail guard having
the above-mentioned structure when the rigid body ball of 100kg mass collides with
the rail guard at a speed of 300km/h at a position deviating from the center of the
rail guard (rightwardly offset about 750mm from the center of the vehicle body). Figs.
5(a) to 5(c) show deformations occurring when an elapse time T after the collision
is 0sec, 0.015sec, and 0.03sec.
[0034] As shown in Figs. 5(a) to 5(c), when the rigid body ball of 100 kg mass collides
with the rail guard at 300km/h at the position deviating from the center, the resulting
collision energy is absorbed mainly by deformation of the rail guard and a reaction
force for moving the rigid body ball off the track is generated for 0.03 second after
the collision, because an attack angle of the rigid body ball with respect to the
rail guard is small.
[0035] Further, Figs. 6(a) to 6(e) show a result of simulation analysis of deformation of
the vehicle body having the above rail guard support structure, which deformation
is caused by a collision load generated by colliding a rigid wall Ob with the vehicle
body. Figs. 6(a) to 6(c) show deformations occurring when deformation strokes Ds are
0mm, 250mm, 500mm, 750mm, and 1000mm.
[0036] In this embodiment, while the energy absorbing pipe member that is tubular with rectangular
cross-section is used as the energy absorbing element, because this pipe member is
easily deformed like bellows to absorb energy and has a reduced weight, other well-known
energy absorbing elements may be used.
[0037] Numerous modifications and alternative embodiments of the invention will be apparent
to those skilled in the art in view of the foregoing description. Accordingly, the
description is to be construed as illustrative only, and is provided for the purpose
of teaching those skilled in the art the best mode of carrying out the invention.
The details of the structure and/or function may be varied substantially without departing
from the scope of the invention and all modifications which come within said scope
of the appended claims are reserved.
1. Structure de support de chasse-pierres d'un véhicule ferroviaire, dans laquelle un
chasse-pierres (1), pour éliminer un obstacle sur une voie pendant le déplacement
du véhicule, est supporté par un châssis de véhicule, dans lequel :
- un élément absorbant l'énergie (5) est disposé derrière la partie frontale (1A)
du chasse-pierres (1) pour s'étendre dans la direction longitudinale du véhicule et
l'extrémité arrière de l'élément absorbant l'énergie (5) est fixée au châssis du véhicule
(10) au moyen d'un dispositif de support d'élément absorbant l'énergie (21),
- les portions de bordure supérieures des parties latérales (1B, 1C) droite et gauche
du chasse-pierres(1) sont supportées par le châssis du véhicule (10) en des endroits
latéraux du dispositif de support d'élément absorbant l'énergie,
caractérisé en ce que
- les parties latérales droite et gauche (1B, 1C) du chasse-pierres (1) qui est supporté
par le châssis du véhicule(10) sont essentiellement situées au même endroit que la
partie arrière de l'élément absorbant l'énergie (5) dans la direction longitudinale
du véhicule.
2. Structure de support de chasse-pierres selon à revendication 1, dans laquelle les
portions de bordure supérieures des parties latérales droite et gauche (1B, 1C) du
chasse-pierres (1) sont fixées au châssis du véhicule (10) au moyen d'un dispositif
de support de chasse-pierres (22) situé à l'avant de la cabine du conducteur (13).
3. Structure de support de chasse-pierres selon la revendication 1 ou 2, dans laquelle
le chasse-pierres (1) est incliné en oblique vers le bas, vers l'avant ou latéralement,
un bloc (9, de forme essentiellement rectangulaire et parallélépipédique, étant fixé
au voisinage d'une parie de bordure supérieure de la partie frontale (1A) du chasse-pierres
(1) et une partie de bordure inférieure de la partie frontale (1A) du chasse-pierres
(1) étant située essentiellement verticalement au-dessous de la face frontale du bloc
(9).