BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a bottom sectional view that shows part of a forefront vehicle equipped with a collision energy absorbing apparatus according to the present invention, the front right half of the collision energy absorbing apparatus cut in the center height position of the apparatus being viewed from the bottom side of the vehicle;
FIG. 2 is a longitudinal sectional view that shows part of the forefront vehicle shown in FIG. 1 in section;
FIG. 3 is a side view of the collision energy absorbing apparatus shown in FIG. 1;
FIG. 4 is a view of an energy absorbing body and a cover shown in FIG. 3, taken in the direction of the arrows A-A;
FIG. 5 is a view of an energy absorbing body and a cover shown in FIG. 3, taken in the direction of the arrows B-B;
FIG. 6 is a view of an energy absorbing body and a cover shown in FIG. 3, taken in the direction of the arrows C-C;
FIG. 7 is a view of an energy absorbing body and a cover shown in FIG. 3, taken in the direction of the arrows D-D;
FIG. 8 is a diagram that shows a broken condition of a cover used in the energy absorbing body shown in FIG. 3;
FIG. 9 is a front view that shows an example of an energy absorbing body;
FIG. 10 is a diagram that shows a crushed condition of the energy absorbing body shown in FIG. 9; and
FIG. 11 is a graph that shows an example of the distribution of a peak load.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Next, on the basis of FIGS. 1 to 9, a description will be given of an embodiment which is applied to a car end part, i.e., a forefront part of a forefront vehicle, which is a railway vehicle equipped with a collision energy absorbing apparatus of the present invention. In a forefront vehicle of the embodiment shown in the figure, the profile of a forefront part 2 thereof is formed so as to provide a convex curved surface forward. As shown in FIGS. 1 and 2, a collision energy absorbing apparatus 50 that absorbs part of the collision energy generated upon collision against an obstacle and the like is arranged in the forefront part 2.
The collision energy absorbing apparatus 50 is installed on each of both sides in the width direction of the forefront vehicle. In FIGS. 1 and 2, only one side in the width direction of the car body is shown. That is, a collision energy absorbing apparatus 50a and a collision energy absorbing apparatus 50b that have the same construction are symmetrically installed on both sides in the width direction of the car body. The reference numeral 10 denotes a coupler that is installed in the forefront part to couple a vehicle and another vehicle together. The coupler 10 is installed, with the longitudinal direction thereof set along the longitudinal direction of the car body, in the center position of the width direction of the car body. The collision energy absorbing apparatuses 50a, 50b are attached to the car end part in the longitudinal direction of the underframe 4.
The collision energy absorbing apparatuses 50a, 50b are constructed by arranging a plurality of energy absorbing bodies in vertical alignment. That is, in each of the collision energy absorbing apparatuses 50a, 50b, a first energy absorbing body 51 and a second energy absorbing body 52, which absorb the collision energy by being crushed upon collision of an obstacle and the like from the car end side, are arranged in two layers in vertical alignment. The first and second energy absorbing bodies 51, 52 are attached to a common support plate 58 in positions near the middle of the car body in the longitudinal direction of the car body. One common third energy absorbing body 53 is connected to a surface near the middle of the car body in the longitudinal direction of the car body, i.e., to a surface on the rear side of the support plate 58. The third energy absorbing body 53 is connected to the underframe 4 via a frame 54 in an end part near the middle of the car body, i.e., in the rear end part. Each of the collision energy absorbing apparatuses 50a, 50b is constituted by the first and second energy absorbing bodies 51, 52, the support plate 58, and the third energy absorbing body 53.
As shown in FIG. 9, each of the first to third energy absorbing bodies 51 to 53, which constitute the collision energy absorbing apparatuses 50a, 50b, is constituted by a cylindrical body 70 that has an octagonal section and a hollow structure inside. The cylindrical bodies 70 are arranged in alignment in a direction in which the axis lines thereof are substantially parallel to the longitudinal direction (fore-and-aft directions and travel directions) of the railway vehicle. This cylindrical body 70 is formed from units to provide an octagonal section as a whole, each unit consisting of an outer wall part 71, an inner wall part 72 and radial wall parts 73 that connect corner parts corresponding to the wall parts 71, 72 on both sides and extend radially, the wall parts having different outside dimensions. The outer wall part 71 and the inner wall part 72 have similar figures in sectional shape. On the inner side of the inner wall part 72 that forms a cylindrical body, there is formed a space 15 that extends axially along the axial direction. In an annular gap between the outer wall part 71 and the inner wall part 72, there is formed a space 74 partitioned by the plurality of radial wall parts 73, 73. The energy absorbing bodies 51 to 53 have the same sectional shape in their axis line directions. Therefore, the energy absorbing bodies 51 to 53 can be manufactured by using extruded sections of aluminum alloy as the material. The first energy absorbing body 51, the second energy absorbing body 52 and the third energy absorbing body 53 are constructed in such a manner that the nearer to the middle of the car body in the longitudinal direction of the car body, i.e., to the rear part they are installed, the larger the sectional area of these energy absorbing bodies will be.
The support plate 58 is formed to provide a peripheral edge of a rough quadrangle, and a guide cylinder 59 with a roughly quadrangular cylindrical shape is attached to the peripheral edge. The guide cylinder 59 is fitted into the guide cylinder plate 60 so that a peripheral surface 59a thereof is slidable on an inner surface 60a of the guide cylinder plate 60. The guide cylinder plate 60 is attached to the car body. Therefore, when the railway vehicle collides against an obstacle and the like, first, the first energy absorbing body 51 and the second energy absorbing body 52 are crushed, and subsequently the third energy absorbing body 53 is crushed. In connection with the crush of the third energy absorbing body 53, the guide cylinder 59 along with the support plate 58 moves toward the middle of the car body in the longitudinal direction of the car body, i.e., rearwards while being guided by the guide cylinder plate 60. Because the first and second energy absorbing bodies 51, 52 are guided by the inner surface 60a of the guide cylinder plate 60 in an intermediate position of the collision energy absorbing apparatus, it is possible for the first and second energy absorbing bodies 51, 52 to exhibit the collision energy absorbing action along the full length without being buckled in the intermediate position. The guide cylinder plate 60 is installed on the car end side of the underframe 4 in the longitudinal direction of the car body. A motorman's cab is constructed near the middle of the car body compared to the guide cylinder plate 60, i.e., at the rear. A flying object protection plate 61 is installed in the car end position of the motorman's cab and the front side of the motorman's cab is covered with the flying object protection plate 61. The guide cylinder plate 60 is installed in an opening formed in the flying object protection plate 61.
As shown in FIG. 3, the leading end positions in the collision direction of the first and second energy absorbing bodies 51, 52 are shifted to a plurality of positions in the longitudinal direction of the car body. That is, the first and second energy absorbing bodies 51, 52 have slightly different lengths in the collision direction, and in the condition supported by the support plate 58, the leading end position of the first energy absorbing body 51 lies on the car end side slightly (ΔL, for example, on the order of 100 mm) compared to the leading end position of the second energy absorbing body 52, i.e., at the front. Due to the difference in the leading end position of these energy absorbing bodies, in the event of a collision the first energy absorbing body 51 begins to be crushed earlier than the second energy absorbing body 52. For example, an example of a concrete crushed condition of the energy absorbing body 51 (52) of FIG. 9 is shown in FIG. 10. The crush of the first and second energy absorbing bodies 51, 52 proceeds, while the cylindrical bodies that constitute each energy absorbing body repeating microbuckling in their axis directions, with their axis lines kept, and being crushed virtually in straight lines. At this time, the first and second energy absorbing bodies 51, 52 absorb the collision energy while the whole being deformed like an accordion hose, and not undergoing total buckling like elbowed bending. This deformation of the first and second energy absorbing bodies 51, 52 is called crush. The first and second energy absorbing bodies 51, 52 after crush obtain, for example, a bellows structure in a shrunk condition. The reference numerals 51a, 51b denote end plates of the energy absorbing body 51 (52), the reference numerals 14a, 14b denote joint plates, and the reference numeral 16 denotes a buckling preventing member. The energy absorbing body 51 (52) shown in FIGS. 9 and 10 has a construction different from that of the energy absorbing body shown in FIG. 3, and is of a construction provided with the two joint plates 14a, 14b. The buckling preventing member 16 is fixed to the joint plate 14a and disposed so as to pierce through an opening of the joint plate 14b. This buckling preventing member 16 fulfills the role of preventing the total buckling of the energy absorbing body 51 (52).
That is, the energy absorbing body 51 (52) is partitioned by the joint plates 14a, 14b in the longitudinal direction. The buckling preventing plate 16 is fixed to the joint plate 14a, and the trailing end of the buckling preventing plate 16 pierces through the joint plate 14b. When the distance from the joint plate 14a to the joint plate 14b in the energy absorbing body 51 (52) shrinks due to crush, the buckling preventing member 16 pierces through the joint plate 14b. Because of this, the energy absorbing body 51 (52) is crushed like an accordion hose without undergoing total buckling. For the energy absorbing body 51 and the energy absorbing body 52, also the longitudinal position of one of the joint plates 14a protrudes from the other as with the positions of the end plates 51a, 52a.
In the two energy absorbing bodies 51, 52 having different lengths, a peak load due to collision is distributed by a slight difference in the crush start period. Therefore, the crush peak loads of the energy absorbing members 51, 52 are reduced and it is possible to mitigate the impact on the car body, passengers and the like. How a peak load is distributed is shown in FIG. 11 as an example. In the case of an arrangement in which the energy absorbing bodies are disposed with their leading ends aligned with each other, as indicated by a thin line in FIG. 11, the crush start begins simultaneously, with the result that a very high peak load occurs at the beginning of the crush start. However, because of the difference in the period of crush start corresponding to the shift ΔL of the position of the energy absorbing bodies 51, 52 as in this embodiment, there occurs a shift in the period of a peak load as indicated by a thick line in FIG. 11, with the result that it is possible to suppress the peak load.
The collision energy absorbing apparatus 50 shown in FIGS. 1 to 3 is provided with a cover 80. The cover 80 has a size large enough to be able to cover the energy absorbing bodies 51, 52 that constitute the collision energy absorbing apparatus 50. The cover 80 is formed in the shape of a box having a roughly rectangular shape as a whole. The cover 80 has the shape of a cylindrical container, with one end thereof closed in the longitudinal direction and the other end opened. The cover 80 that covers the two energy absorbing bodies 51, 52 is constructed as a single member. Incidentally, as shown in FIG. 2, when the shape is such that the car body profile forms a large curved surface in the forefront part 2 of the car body, the cover 80 is constructed so that part of the cover 80 is in a curved shape so as to fit the curved surface of the car body profile. The cover 80 is placed from the car end side of the energy absorbing bodies 51, 52 and attached to the support plate 58. And the cover 80 is supported in a cantilevered manner on an end part near the middle of the car body in the longitudinal direction of the car body of the energy absorbing bodies 51, 52, i.e., on the base end side. Although in this cantilevered support of the cover 80, the cover 80 is supported by the energy absorbing apparatus as with the support plate 58, the cover 80 may be attached to members on the side of the railway vehicle, such as the guide cylinder plate 60. The cover 80 can cover the whole of the energy absorbing bodies 51, 52 which are arranged in vertical alignment by one piece, and is attached to the support plate 58 on the opening side. The cover 80 combines a prescribed static strength and the collision energy absorption performance that complements the impact energy absorption function of the energy absorbing bodies 51, 52. Thanks to its static strength, the cover 80 prevents irregularities, such as the breakage of cylindrical bodies of aluminum alloy, i.e., the energy absorbing bodies 51, 52 in each of the stages of transportation, storage, assembling and the like of the collision energy absorbing apparatus 50. Furthermore, even after the mounting of the collision energy absorbing apparatus 50 on the car body, in the event of the occurrence of a slight collision, it is also possible that the impact is absorbed by the cover 80. In such cases, the cover 80 fulfills the function of absorbing collision energy due to a slight collision by being broken and deformed. In the case of a slight collision, no deformation occurs in the energy absorbing bodies 51, 52 because of the deformation of the cover 80. When the collision energy is absorbed only by the deformation of the cover 80, the action of replacement of the cover 80 alone is sufficient and, therefore, it is unnecessary to carry out a large-scale repair or to replace the collision energy absorbing apparatus 50 itself. There may sometimes be cases where in the event of a collision, the collision energy cannot be absorbed only by the deformation of the cover 80 and the impact reaches the energy absorbing bodies 51, 52. In the case of such a large collision, an obstacle or the like collides against the cover 80 immediately before collision against the energy absorbing bodies 51, 52, and the cover 80 is divided into an upper portion and a lower portion along a breakage-intended path M. Because the breakage of the cover 80 occurs a little before the occurrence of a load peak due to the crush of the energy absorbing bodies 51, 52, it is possible to suppress the crush peak load of the energy absorbing bodies 51, 52 to a greater extent.
For an embodiment of the cover 80, the construction of the cover 80 will be described on the basis of FIGS. 3 to 7. The cover 80 has the shape of a cylindrical container that forms a roughly rectangular parallelepiped and the part to be attached to the support plate 58 forms an opened pentahedron. The cover 80 is constituted by a front end part 81 positioned on the car end side, side wall parts 82, 83 positioned on both sides of the width direction of the car body, and a bottom wall part and a top wall part that are vertically positioned. The front end part 81 is constituted by a substantially flat plate member. In the front end part 81, a first slit 84 is formed in a vertically middle zone along a substantially horizontal direction. As shown in FIG. 4, the installed position of this first slit 84 virtually corresponds to the space part between the first energy absorbing body 51 and the second energy absorbing body 52 as shown in FIG. 4. Furthermore, as shown in FIG. 3, FIG. 5 and FIG. 6, a plurality of second slits 85, 86 are formed in the vertically middle zone of the side wall parts 82, 83 in order to facilitate the vertical breakage of the side wall parts themselves. The second slits 85, 86 are formed in the longitudinal direction of the car body, i.e., along the axis line direction of the energy absorbing bodies 51, 52. The second slits 85, 85 on the car end side and the second slits 86, 86 on the middle side of the car body in the longitudinal direction of the car body are formed in the side wall parts 82, 83. The second slit 85 on the car end side is formed so as to provide a wider gap than the second slit 86, and these slits are formed discontinuously along the longitudinal direction of the car body. The first slit 84 and the second slits 85, 86 are formed in a substantially intermediate position in the vertical direction of the cover 80, and this position is the breakage-intended path M shown in FIG. 3. Incidentally, although an example in which the second slits 85, 86 are formed discontinuously was shown, it is obvious that the second slits 85, 86 may be formed continuously. The distance of discontinuity is short. The first slit 84 and the second slits 85, 86 are formed in order to facilitate the vertical breakage of the cover 80 when an obstacle or the like collides against the cover 80 from the car end side.
When the railway vehicle collides against an obstacle, a large impact load acts on the car end side, i.e., the front end part 81 of the cover 80. The condition in which the cover 80 is broken in this case is shown in FIG. 8. Because in the cover 80, the parts of the first slit 84 and the second slits 85, 86 have lower strength than other parts, they become parts that are easily broken, and they are broken along the breakage-intended path M. For the cover 80, a condition in which the cover 80 is vertically divided into two portions as a broken piece 80a and a broken piece 80b is the most ideal condition. FIG. 8 schematically shows how the cover 80 is broken by being divided into two parts in the vertical direction intersecting the collision direction (the direction indicated by the arrow in FIG. 3 (the direction substantially along the longitudinal direction of the car body)). The broken pieces 80a, 80b are deformed so as to open vertically. Therefore, because there are relatively few members that provide obstacles in the vertical direction of the cover 80, the behavior of the broken pieces 80a, 80b is allowed in the limited interior of the car body. On the occasion of this breakage, the cover 80 can complement the absorption function of the energy absorbing bodies 51, 52 by absorbing part of the collision energy. And after its opening, the cover 80 does not prevent the energy absorption function of the energy absorbing bodies 51, 52. Incidentally, it is also conceivable to adopt a construction in which further slits are provided in positions of the bottom wall part and top wall part near the middle of the car body in order to promote the deformation of the cover 80, thereby dividing the cover 80 into two portions in the vertical direction. Incidentally, the rigidity of the cover 80 is lower than that of the energy absorbing bodies 51, 52 and hence the cover 80 is deformed by a slight impact. Therefore, even if the deformation of the cover 80 is such that the cover 80 is not divided into two portions in the vertical direction, the cover 80 does not exert an adverse effect on the energy absorption function of the energy absorbing bodies 51, 52.
Although the above-described embodiment of the collision energy absorbing apparatus provided with a cover is applied to the forefront part of the railway vehicle, the present invention is not limited to this. Even when the collision energy absorbing apparatus is arranged in car end portions of intermediate vehicles connected to the forefront vehicle in a train of railway vehicles, the collision energy absorbing apparatus exhibits similar operations and effects. Furthermore, it is needless to say that the present invention can be applied to a collision energy absorbing apparatus containing one energy absorbing body. A train of vehicles is constituted by forefront cars at the front and the tail and a required number of intermediate cars. For example, when the forefront vehicle or the vehicle at the tail collides against an obstacle or other vehicles, collision occurs successively not only between the intermediate vehicles adjacent to the forefront vehicle or the vehicle at the tail, but also between the end parts of adjacent intermediate vehicles. By using the collision energy absorbing apparatus of the present invention, particularly to match the height of underframes of high strength in the end part of the forefront vehicle or the vehicle at the tail and in each car end part of the intermediate vehicles, it is possible to effectively absorb an impact by use of the collision energy absorption apparatus even when a collision occurs in any place of the train.
Patent Application
20070261592
