GB2404635A

GB2404635A - Energy absorption device

Info

Publication number: GB2404635A
Application number: GB0318673A
Authority: GB
Inventors: Aires Benevides Prata; Nuno Martins; Antonio Paulo Tavares Custodio
Original assignee: Bombardier Transportation GmbH
Current assignee: Alstom Transportation Germany GmbH
Priority date: 2003-08-08
Filing date: 2003-08-08
Publication date: 2005-02-09
Anticipated expiration: 2023-08-08
Also published as: GB0318673D0; GB2404635B

Abstract

An energy absorption device comprises a front impact beam 20, a back beam 40 and one or more energy absorbing elements 60, arranged between the front impact beam and the back beam, wherein the energy absorption device comprises one or more sliding beams 30 that are rigidly connected to the front impact beam. The back beam has one or more openings 50, through which the one or more sliding beams are fed, the openings, guiding and limiting movement of sliding beams essentially to a direction parallel to a longitudinal axis of the sliding beams, and wherein the energy absorbing elements are arranged essentially parallel to the longitudinal axis of sliding beams. In another aspect of the invention there is provided a vehicle, in particular a track-bound vehicle comprising an energy absorption device according to the invention, in particular a vehicle wherein the device is integrated in the structural frame of the front cabin of the vehicle.

Description

2404635

Energy absorption device for absorbing impact energy of a vehicle

10001] The present invention relates to an energy absorption device for absorbing impact energy of a vehiclc comprising one or more energy absorbing elements for 5 absorbing the energy of an impact, for example of a collision of a vehicle. A particular embodiment of the invention is a vehicle, in particular a rail-bound vehicle, comprising an energy absorption device.

[0002| In the use of impact on a vehicle, for example in a collision of a driving 10 vehicle, the impact energy is dissipated predominantly in deformation of parts of the vehicle and in residual kinetic energy of the vehicle or parts of the vehicle. In an attempt to reduce the damaging effects of an impact numerous solutions are presented in the prior art.

15 [0003] United States Patent number 6,158,356 describes an energy absorbing device for use in vehicles, in particular railroad vehicles, comprising two flat rings that are inserted between the drivers cabin and a coach body, the rings being attached at their upper part near the roof of the vehicle by a pivot beam and which rings comprise at a bottom part near the floor of the vehiele damper devices for absorbing energy of a 20 collision. On impact of the vehicle the pivot member causes the front ring to rotate towards the back ring pushing the damper into the cabin chassis whereby the damper absorbs impact energy.

[00041 In US 202/0073887 a rail vehicle is described having a rigid frame covering 25 the full front of the driver's cabin arranged over a number of energy absorbing elements to protect the cabin from collision impacts above the frame of the vehicle.

[0005] The disadvantage of the prior art energy absorption devices is that the energy absorption capacity is not sufficient, in particular for modern high-speed trains and in 30 the case of serious collisions. Therefore, there is still a risk of serious damage to the vehicle and persons in the vehicle. Moreover, the devices do not perform optimally and hence are not reliable in all collision circumstances. In particular, where the direction of

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impact is oblique to the longitudinal axis of the vehicle, the impact energy is not efficiently absorbed. In this respect, the longitudinal axis of the vehicle is the axis extending along the length of the car body of the vehicle. In straight tracks the longitudinal axis of the vehicle is parallel with the driving direction of the vehicle. In 5 curved tracks however there is an oblique angle between the driving direction and the vehicle longitudinal axis. A collision impact on a curved track hence transfers force and energy to the vehicle at an oblique angle. It has been found that in such circumstances the energy absorption devices of the prior art are inadequate.

10 [0006] In DE 198 03501 an energy absorption device for a train is described wherein normal buffers are mounted on a buffer plank that is movably connected by an extension engaging a guidance mounted in a length direction below the car frame of the train compartment, which buffer plank deforms in a controlled way upon an impact exceeding the absorption capacity of the normal buffers.

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[0007] The disadvantage of this energy absorption device is that the energy absorption capacity is not sufficient, in particular for modern high-speed trains and in cases of serious collisions. The deformation length is too short to allow sufficient energy absorption. Further, impacts at a level above the level of the buffer plank are

20 insufficiently absorbed and lead to an uncontrolled deformation of the front part of the train, in particular the driver's cabin, which endangers the driver and passengers in the compartments behind the driver's cabin.

[0008] There hence is a need for an improved energy absorption device having a high

25 energy absorption capacity, that is reliable and has an optimal energy absorption independent of the level or direction of impact, thus providing increased safety for the driver and passengers, in particular for modern high-speed trains and in cases of serious collisions.

30 [0009| According to the present invention there is provided an energy absorption device, comprising a front impact member, a back member and one or more energy absorbing elements, arranged between the front impact member and the back member,

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wherein the energy absorption device comprises one or more sliding members that are rigidly connected to the front impact member, the back member having one or more openings, through which the one or more sliding members are movable, the openings, guiding and limiting movement of the sliding members to essentially a direction parallel 5 to a longitudinal axis of the sliding members, and wherein the energy absorbing elements are arranged essentially parallel to the longitudinal axis of the sliding members.

[0010J In another aspect of the invention there is provided a vehicle, in particular a

10 track-bound vehicle comprising an energy absorption device according to the invention.

[0011] In a particularly preferred embodiment of the vehicle, the energy absorption device has a shape and dimensions corresponding to the shape and dimensions of a front cabin of the vehicle and preferably is integrated in the structural frame of the front cabin

15 of the vehicle, wherein the front impact member is in the front of the cabin, the back member is in the back of the cabin and the sliding members and absorbing elements are in a floor part of the cabin and the front impact member is connected in a front frame of the cabin to diagonal members having a crumple zone, which front frame is connected to a back frame of the cabin comprising the back member connected to back girders.

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[0012] The energy absorption capacity in the design of the energy absorption device according to the invention is significantly improved, reducing the risk of structural damage to the vehicle that is expensive or impossible to repair and improving the safety of passengers in the vehicle.

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[0013] References to "Front" and "back" are to be understood in terms of the normal directions of travel of the vehicle. Thus, the front member is located in front of the back member when the vehicle is travelling normally and in the event of a collision would be impacted before the back member. The energy absorption device may be located in the

30 sides or rear of the vehicle. In such cases, the front member and back member are to be understood as being arranged such that, in a collision, the front member is impacted first, before the back member.

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|0014] The energy absorption device provides an optimal absorption of energy also when the impact direction is oblique to length axis of the sliding members or to the longitudinal direction of a vehicle on which the device is mounted. The vehicle 5 comprising the energy absorption device of the invention is hence more reliable in various different collision circumstances.

Brief description of the drawings,

10 The following is a description of an embodiment of the invention given by way of example only and with reference to the appended drawings in which:

Fig. 1 is a schematic diagram of one embodiment of the impact energy absorption device according to the invention before an impact occurred and

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Fig. 2 is the impact energy absorption device of Fig. 1 after an impact has occurred.

Detailed description the invention

20 [0015] Fig. 1 is a schematic diagram of one embodiment of the impact energy absorption device according to the invention before an impact has occurred, showing a front impact beam (20), a back beam (40) two energy absorbing elements (60), arranged between the front impact beam (20) and the back beam (40) and two sliding beams (30)

• • • •

• ' • * that are rigidly connected to the front impact beam (20). The back beam (40) has two • ♦ • •

25 openings (50), through which the sliding beams (30) are fed, guiding and limiting movement of the sliding beams (30) essentially to a direction parallel to a longitudinal

• • •

' ** axis of the sliding beams (30). The energy absorbing elements (60) are arranged

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essentially parallel to the longitudinal axis of sliding beams (30). Two diagonal beams

• • • (80) connect the frontal impact beam (20) with the top frame beam.

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.. . 30 • * •

[0016] By front beam (20) is meant the beam that is intended to receive the impact, i.e. when mounted on a vehicle, the beam first occurring when going towards a vehicle

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along a line parallel to the longitudinal axis of the vehicle. Hereafter all axes are given relative to the dimensions of a vehicle, so the longitudinal axis is in the length direction of the car body of the vehicle, the vertical axis is vertical to the ground surface and the transverse axis is perpendicular to both other directions. Preferably, the sliding beams 5 (30) are perpendicular to the front impact beam (20) and the back beam (40). When mounted on a vehicle the longitudinal axis of the sliding beams are preferably parallel to the longitudinal axis of the vehicle. The front impact beam (20) and preferably also the back beam (40) and the preferably at least 2 sliding beams (30) have a high stiffness such that an oblique impact does not cause deformation and results in movement of the 10 sliding beams essentially only in a direction parallel to the longitudinal axis of the sliding beams. The top frame beam (10) is located approximately but not necessarily in the same vertical plane as the back beam (40) and is stiffly mounted to the remaining vehicle, as is the back beam (40). The two diagonal beams (80) preferably have two crumple activation areas, preferably located approximately at 1 fifth and 4 fifths along 15 their length.

[0017] Fig. 2 is a schematic representation of the impact energy absorption device of Fig. 1 after an impact has occurred. In a collision situation the impact energy is transferred to the front impact beam (20). The front impact beam (20) has a high 20 stiffness so as to evenly distribute the forces of the impact over the surface of the beam without deformation, irrespective of the angle or place of impact. The impact energy is thereby evenly distributed over the energy absorption elements (50) and the differential of forces are transferred to at least 1, most preferably at least 2 sliding beams that are rigidly connected to the front impact beam (20) and the diagonal beams (80). The one or 25 more sliding beams (30) and the back beam (40) preferably also have a very high stiffness, so as to prevent deformation by an oblique impact. Upon impact, the sliding beams (30) move through the openings (50) and the energy absorption elements (50) are compressed exclusively in a direction parallel to the sliding beam axis and absorb the impact energy.

[0018] Preferably, the front impact beam (20) covers a substantial part of the area exposed to a hypothetical impact. Preferably, the front impact beam (20) has a length of

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at least 50%, preferably at least 75%, even more preferable at least 80% of the width (in transverse direction) of the vehicle. The height (in vertical direction) of the front impact beam (20) is preferably at least 20, preferably at least 30 cm, more preferably at least 40 cm. The front impact beam (20) can be massive but can for example also be an open 5 frame.

[0019] The sliding beams (30) are fed through the openings in the back beam (40) that guide and limit movement of the sliding beams and the front impact beam (20) essentially to a direction parallel to a longitudinal axis of the sliding beams (30), such

10 that the energy absorbing elements (60), that are arranged essentially parallel to the longitudinal axis of the sliding beams (30), experience only a force in the direction parallel to the longitudinal axis of the sliding beams, irrespective of the angle of impact. Preferably, the longitudinal axis of the sliding beams (30) is parallel to the longitudinal axis of the vehicle. Preferably the openings (50) in the back beam are shaped to allow a 15 minimum of play in a direction other than parallel to the sliding beam axis. To that aim the openings are preferably square or rectangular and preferably the width of the opening along the sliding beam axis is significantly higher than one or two of the other dimensions of the openings. Preferably the sliding movement of the sliding beams in the openings (50) of the back beam (40) is facilitated by friction reducing means, like 20 lubricants or bearings.

[0020] The energy absorption elements (60) that can be used in the invention are known to the skilled man and are chosen in view of achieving as high as possible energy absorption on an impact. Many energy absorption elements have a strongly anisotropic

25 energy absorption behaviour, with a very high energy absorption if exposed to an impact with a direction parallel to it's optimum impact axis and a significantly lower impact energy absorption when exposed to an impact with a direction at an angle with the optimum absorption axis. In the case of anisotropic energy absorption elements the energy absorbing elements (60) are arranged such that their axis of optimum energy 30 absorption is essentially parallel to the longitudinal axis of the sliding beams (30). Preferably, the energy absorption devicc comprises at least 2 sliding beams and at least 2 absorption elements.

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[0021] Preferably the energy absorption device comprises a front frame (110) comprising the front impact beam (20) and diagonal beams (80) and a back frame (120) comprising the back beam (40) and back girders (70) and top beam (10), wherein the

5 front frame and back frame are connected at diagonal beams of the back and front frame (110). The back and front frame (110) may have separate diagonal beams or share a common upper girder. The advantage is that the front and back girders improve the structural stiffness of the energy absorption device and improve resistance to deformation in the case of an oblique impact. In this embodiment, the resistance to 10 deformation of the diagonal beams (80) is low compared to the resistance of deformation of the front impact beam and the back beam (40) to prevent that, on impact, the resistance to deformation of the girders can cause deformation of the front impact beam. Especially in case of a high vertical dimension of the front impact beam (20), diagonal beams (80) are preferred to help resist rotational deformation of the frontal 15 impact beam (20) around the point where the sliding beams are mounted.

[0022] In a preferred embodiment the energy absorption device (10) has a shape and dimensions corresponding to the shape and dimensions of a front vehicle cabin with the front impact beam (20) in the front of the cabin, the back beam (40) placed in the back

20 of the cabin and the sliding beams (30) and absorbing elements (60) in a floor part of the cabin. In a particularly preferred embodiment thereof the energy absorption device, preferably having a front frame (110) and back frame (120) with girders (70 and 80) can be integrated in the structural frame of the front cabin of a vehicle. Because of the size of the energy absorption elements that can be accommodated, this embodiment of the 25 invention allows for creating a very high energy absorption capacity compared to the energy absorption devices of the prior art. Preferably, the distance (90) (in the longitudinal direction) between the frontal impact beam (20) and the back beam (40) is at least 30 cm, preferably at least 50 cm, more preferably at least 70 cm and most preferably at least 100 cm. Preferably the length (in the longitudinal direction) of the 30 energy absorbing elements (60) is at least 20 cm, preferably at least 30 cm, more preferably at least 50 cm and most preferably at least 75 cm.

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[00231 1° case the front cabin of the vehicle is a driver's cabin, safety measures are preferably provided to protect the driver. Preferably a safety zone is provided, such that the cabin in that the energy absorption device according to the invention comprises an incompressible residual length of the absorption elemnets (60) between the frontal 5 impact beam (20) and the back beam (40). The deformation of the absorption elements (60) is halted at the incompressible length providing a space between the stiff front impact beam or front frame (110) and the stiff back beam or back frame (120) sufficient to secure safety for the driver.

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III*

10 [0024] The invention further relates to a vehicle comprising an energy absorption device (10) as described above. In one embodiment the energy absorption device is mounted at the front of the vehicle. In a preferred embodiment the vehicle comprises an energy absorption device (10) as described above wherein the energy absorption device has a shape and dimensions corresponding to the shape and dimensions of a front cabin 15 of the vehicle and wherein the frontal impact beam is in the front of the cabin, the back beam (40) is in the back of the cabin and the sliding beams and absorbing elements are in a floor part of the cabin. Preferably, in this embodiment, the energy absorption device is integrated in the structural frame of the front cabin of the vehicle. For example, the vehicle comprises an energy absorption device comprising a front frame (110) 20 comprising the front impact beam (20) and diagonal beams (80) and a back frame (120) comprising the back beam (40) and back girders (70), wherein the front frame (110) and back frame (120) are connected at upper girders of the back and front frame and are shaped to form the frame structure of the front cabin of the vehicle. The back frame (120) forms the back of the driver's cabin, the front frame (110) forms the roof and 25 front of the driver's cabin and the sliding beams and absorbing elements are in a floor part of the drivers cabin.

[0025] As opposed to prior art vehicles, in the above embodiment of the invention where the energy absorption device is integrated in the front cabin of the vehicle, the 30 front cabin will be damaged on impact and repairs are required. Nevertheless, because deformation occurs in defined places, in particular the energy absorption elements (60) and, in some embodiments, also in the diagonal beams (80) of the front and back frame,

the repairs are largely limited to such defined places. Because of the much higher energy absorption capacity, the chances of much more expensive or irreparable structural damage to the vehicle are reduced compared to the prior art. Small impact energy absorption elements known in the art are preferably provided in addition to the energy absorption device according to the invention to prevent damage and repairs to the energy absorption device according to the invention by absorbing the impact energy from small but more frequently occurring impacts, for example up to a speed of about 5 to 10 km/h.

[0026] The vehicle according to the invention preferably comprises a residual incompressible length parallel to the absorbing elements (40), between the frontal impact beam (20) and the back beam (40) to provide an incompressible safety zone in the driver's cabin for a driver. The driver seat can be placed in the incompressible safety zone.

[0027] In another embodiment of the vehicle according to the invention the vehicle further comprises a driver's seat, which seat is connected to the front frame (110) that is movable on impact such that on deformation impact the seat moves back with the front frame into an incompressible safety zone. Alternatively, there is provided an opening in the back frame (120) and a safety zone behind the back frame (120) and the seat is arranged to move upon deformation impact with the front frame (110) through the opening in the back frame (120) into the safety zone behind the back frame (120).

[0028] The scope of the invention is not limited by the specific drawings. The skilled person can easily create other embodiments of the invention within the concept as described above. The invention further relates to an energy absorption element as hereinbefore described with reference to the figures 1 and 2.

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Claims

An energy absorption device (10) for absorbing impact energy of a vehicle, comprising a front impact member (20), a back member (40) and one or more energy absorbing elements (60), arranged between the front impact member (20) and the back member (40), wherein the energy absorption device comprises one or more sliding members (30) that are rigidly connected to the front impact member (20), the back member (40) having one or more openings (50), through which the one or more sliding members (30) are fed, the openings (50), guiding and limiting movement of sliding members (30) essentially only in a direction parallel to a longitudinal axis of the sliding members (30) and wherein the energy absorbing elements (60) are arranged essentially parallel to the length axis of sliding members (30).

The energy absorption device according to claim 1 comprising at least 2 sliding members (30), at least 2 openings (50) in the back member (40) and at least 2 absorption elements (60).

The energy absorption device according to claims 1 or 2, wherein the length of the front impact member (20) and of the back member (40) is at least 50%, preferably at least 80% of the width of the vehicle

The energy absorption device according to claims 1 to 3, wherein the front impact member (20), the one or more sliding members (30) and the back member (40) have a stiffness in shear and bending of at least 10 times that of the energy absorption elements (60).

The energy absorption device according to claims 1 to 4, wherein the energy absorption elements (60) have an anisotropic energy absorption behaviour and are arranged such that their axis of optimum energy absorption is essentially parallel to the longitudinal axis of the sliding members (30).

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6. The energy absorption device according to claims 1 to 5, comprising a front frame (110) comprising the front impact member (20) and diagonal members with crumple zones (80) and a back frame (120) comprising the back member (40) and back girders (70), wherein the front frame (110) and back frame (120) are connected at upper points of the back and front frame.

7. The energy absorption device according to claim 6, wherein the resistance to deformation of the diagonal members (80) with crumple zones is low compared to the resistance of deformation of the front impact member and the back member (40) and the sliding members.

8. The energy absorption device according to any preceding claim, wherein the device has a shape and dimensions corresponding to the shape and dimensions of a front vehicle cabin with the front impact member (20) in the front of the cabin, the back member (40) placed in the back of the cabin and the sliding members (40) and absorbing elements (60) in a floor part of the cabin.

9. The energy absorption device according to preceding claim, wherein the length (in longitudinal direction) of the energy absorbing elements (60) is at least 20 cm.

10. The energy absorption device according to any preceding claim, wherein the distance (90) (in longitudinal direction) between the frontal impact member (20) and the back member (40) is at least 30 cm, preferably at least 50 cm.

11. The energy absorption device according to any of the preceding claims, wherein the energy absorption devices have a defined residual incompressible length that with the front and back frame define a safety envelope.

12. A vehiclc comprising an energy absorption device (10) according to any one of the preceding claims.

13. A vehicle according to claim 12, wherein the energy absorption device has a shape and dimensions corresponding to the shape and dimensions of a front cabin of the vehicle and wherein the front impact member is in the front of the cabin, the back member (40) is in the back of the cabin and the sliding members and absorbing elements are in a floor part of the cabin.

14. A vehicle according to any of claim 13, wherein the energy absorption device is integrated in the structural frame of the front cabin of the vehicle.

15. A vehicle according to any of claims 12 to 14, comprising a front frame (110) comprising the front impact member (20) and diagonal members (80) with crumple zones and a back frame (120) comprising the back member (40) and back girders (70), wherein the front frame (110) and back frame (120) are connected at upper girders of the back and are shaped to form the frame structure of the front cabin of the vehicle.

16. The vehicle according to claim 15, wherein the back frame (120) forms the back of the driver's cabin and wherein the front frame (110) forms the roof and front of the driver's cabin and wherein the sliding members and absorbing elements are in a floor part of the drivers cabin.

17. The vehicle according to any one of claims 12 to 16, further comprising a driver seat, which seat is connected to the front frame (110) and on deformation impact moves back with the front part into an incompressible safety zone.

18. The vehicle according to claim 17, comprising an opening in the back frame (120) and a safety zone behind the back frame (120) and wherein the seat is arranged to move upon deformation impact through the opening in the back frame (120) into the safety zone behind the back frame (120).

19. The vehicle according to claim 17, wherein the energy absorption device comprises a residual incompressible length between the front impact member

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(20) and the back beam (40) providing an incompressible safety zone in the driver's cabin and wherein, on deformation impact, the driver seat moves towards the back frame (120) into said safety zone.

20. An energy absorption device substantially as hereinbefore described having reference to the accompanying figures.

21. A vehicle substantially as hereinafter described.