WO2005085009A1

WO2005085009A1 - A protection device for a vehicle

Info

Publication number: WO2005085009A1
Application number: PCT/SE2005/000235
Authority: WO
Inventors: Erik Dahlberg
Original assignee: Scania Cv Ab (Publ)
Priority date: 2004-03-08
Filing date: 2005-02-22
Publication date: 2005-09-15
Also published as: SE0400569L; DE112005000342T5; SE0400569D0; SE528073C2

Abstract

The present invention relates to a protection device for a vehicle, which with advantage is a form of underrun protection. The protection device comprises a beam element (2) adapted to being subjected to a collision force (F) when an object collides with the vehicle (1), and at least two energy-absorbing elements (3, 4). The construction of the energy-absorbing elements (3, 4) is such that they become deformed in an energy-absorbing manner when they are subjected to a collision force (F) exceeding a certain value and acting in a direction which is within a defined angle range (A1, A2) relative to an intended direction of deformation (3c, 4c) of the respective energy-absorbing elements (3, 4), and that they become deformed without substantially any energy being absorbed when they are subjected to a collision force (F) exceeding said certain value and acting in a direction which is outside said angle range (A1, A2). The energy-absorbing elements (3, 4) are fitted to the vehicle in such a way that their respective directions of deformation (3c, 4c) are at an angle to one another.

Description

Protection device for a vehicle

BACKGROUND TO THE INVENTION, AND STATE OF THE ART

The invention relates to a protection device for a vehicle according to the preamble of claim 1.

A relatively large percentage of all those killed in vehicle collisions are persons travelling in passenger cars which collide with heavy vehicles. There are substantially two main reasons for the high mortality in accidents of this kind. The first is that a heavy vehicle has a high kinetic energy relative to a passenger car. The second is that passenger cars, being considerably lower, risk ending up under a heavy vehicle with which they collide. To reduce the effects of collisions between passenger cars and heavy vehicles, so-called underrun protection has been introduced. Underrun protection is fitted at the front of heavy vehicles at a relatively low level above ground. There is also underrun protection which is fitted to rear and side portions of heavy vehicles.

There are in principle rigid and deformable forms of underrun protection. Rigid underrun protection prevents a passenger car from ending up under a heavy vehicle in a collision. Rigid underrun protection thus reduces the amount of damage and number of fatalities which are due to this cause. Deformable underrun protection also provides energy-absorbing deformation so that the effects of a heavy vehicle's high kinetic energy on persons in a passenger car with which it collides are reduced. Using deformable underrun protection thus reduces the amount of damage and number of fatalities which are due to the two main causes mentioned above.

A known practice is to provide deformable underrun protection in the form of a forward beam element which has an extent in the transverse direction of the vehicle and is supported by a number of energy-absorbing elements which have an extent in the longitudinal direction of the vehicle. The energy-absorbing elements are so constructed as to become deformed in a controlled manner when subjected in their longitudinal direction to a collision force exceeding a certain value. This deformation leads to kinetic energy being absorbed in a controlled manner so that the effects of a collision on persons travelling in a passenger car which collides with a heavy vehicle are substantially reduced. In many cases, however, the passenger car involved in the collision is moving in a direction which is not entirely opposite to the direction of movement of the heavy vehicle. In such cases the resulting collision force imposes more or less oblique loads on the beam and the energy-absorbing elements, with consequent risk that the energy-absorbing elements will break without performing an energy-absorbing function. Known forms of underrun protection thus perform a more or less reduced function in cases where the direction of movement of the passenger car is not entirely opposite to the longitudinal direction of the heavy vehicle. US 6 068 329 refers to an example of such underrun protection fitted to the rear of a heavy vehicle.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a protection device for a vehicle, which during a collision with an object performs a desired energy-absorbing function which is substantially independent of the direction of movement of the object relative to the protection device.

The object indicated above is achieved by the protection device mentioned in the introduction which is characterised by what is indicated in the characterising part of claim 1. The purpose of the energy-absorbing element is to provide controlled deformation during a collision between primarily a heavy vehicle and a passenger car so that the effects of the heavy vehicle's kinetic energy on persons in the passenger car are considerably reduced. Such energy-absorbing elements are usually so constructed as to provide controlled deformation when subjected to a sufficiently great collision force which impinges upon the energy-absorbing elements at an angle not too greatly differing from the intended direction of deformation of the energy-absorbing elements. The various energy-absorbing elements can thus provide controlled deformation within a relatively well-defined angle range. If the direction of the collision force is outside said angle range, the energy-absorbing element breaks without any substantial absorption of kinetic energy. As the first energy-absorbing element and the other energy-absorbing elements are here fitted in such a way that their directions of deformation are at an angle to one another, their respective angle ranges do not coincide. Said angle ranges therefore form a larger combined angle range within which at least one of the energy-absorbing elements absorbs in an energy-absorbing manner. The protection device can thus perform a desired energy-absorbing function even when the direction in which a passenger car is travelling when it collides with a heavy vehicle is different from the direction in which the heavy vehicle is travelling.

According to one embodiment of the present invention, the first and second energy- absorbing elements are fitted to the vehicle in such a way that their angle ranges adjoin one another. The result is a combined angle range comprising the aggregate of the angle ranges of the respective energy-absorbing elements. There is thus assurance that in a collision one energy-absorbing element will become deformed in an energy- absorbing manner while the other energy-absorbing element becomes deformed without substantially any energy being absorbed. There will thus always be a predetermined absorption of kinetic energy substantially irrespective of the collision angle between the passenger car and the heavy vehicle. The first and second energy- absorbing elements can be fitted to the vehicle in such a way that their angle ranges at least partly overlap one another. Within the region where the angle ranges of the energy-absorbing elements overlap one another, both of the energy-absorbing elements will provide deformation with absorption of energy. The protection device may comprise substantially any desired number of energy-absorbing elements fitted to the vehicle in such a way that their angle ranges together form a combined angle range within which a certain number of energy-absorbing elements will always become defonned in an energy-absorbing manner while the other energy-absorbing elements become deformed without substantially any energy being absorbed. In this case the energy-absorbing elements may be arranged so that their respective angle ranges adjoin or overlap one another so as to form a combined angle range within which a certain number of energy-absorbing elements will always become deformed in an energy-absorbing manner . Absorption of kinetic energy in substantially all directions of collision is thus provided to an extent such as to provide substantially optimum protection against the risk of harm to persons in a passenger vehicle which collides with a heavy vehicle. The protection device may with advantage comprise four energy-absorbing elements fitted to the vehicle in such a way that their angle ranges together form a combined angle range within which two of the energy-absorbing elements become deformed in an energy-absorbing manner while the other two energy-absorbing elements become deformed without substantially any energy being absorbed.

According to another embodiment of the present invention, the beam element is of substantially rigid construction. The purpose of the beam element is to prevent a passenger vehicle from running past it and ending up under the heavy vehicle. Rigid construction is therefore advantageous in that there will be substantially no deformation during a collision. The beam element has with advantage an external contact surface with a convex curved shape. Such a curved beam element provides a contact surface which may be substantially at a right angle to the collision force even in cases where the direction of movement of the passenger vehicle is substantially different from that of the heavy vehicle. The transmission of the collision force to the energy-absorbing elements is thus facilitated.

According to one embodiment of the present invention, the energy-absorbing elements are connected to a rigid element of the vehicle. Said rigid element is with advantage a frame structure of the vehicle. Connecting one end of each of the energy-absorbing elements to a suitable frame structure of the vehicle provides the energy-absorbing elements with secure fastening in the vehicle. The deformation which occurs in an accident is thus provided substantially with exclusion of the energy-absorbing elements. Said frame structure may be a longitudinal side-member of the vehicle. Most heavy vehicles have two parallel longitudinal side-members which it is advantageous to connect to the energy-absorbing elements.

According to one embodiment of the present invention, the protection device takes the form of deformable underrun protection. Deformable underrun protection uses the rigid beam element to prevent a passenger car from ending up under the heavy vehicle during a collision. The amount of damage and number of fatalities which are due to this cause are thus reduced. Deformable underrun protection also provides energy- absorbing deformation by means of the energy-absorbing elements so that during a collision the effects of the heavy vehicle's kinetic energy on persons in the passenger car are reduced. The amount of damage and number of fatalities which are due to this cause are thus reduced.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention are described below by way of examples with reference to the attached drawings, in which:

Fig. 1 depicts a first embodiment of underrun protection according to the present invention,

Fig. 2 depicts a second embodiment of underrun protection according to the present invention and Fig. 3 depicts a third embodiment of underrun protection according to the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

Fig. 1 depicts underrun protection fitted to a front portion of a heavy vehicle 1. The underrun protection comprises a substantially rigid beam element 2 which extends substantially across the whole width of the vehicle. The beam element 2 is fitted at such a level above ground as to guarantee its coming into contact with a passenger vehicle which collides head-on with the heavy vehicle 1. The beam element 2 is therefore intended to prevent the passenger vehicle ending up under the heavy vehicle, which is one of the main causes of the high mortality in collisions between passenger vehicles and heavy vehicles. The beam element 2 is here supported by a first elongate energy-absorbing element 3 and a second elongate energy-absorbing element 4. The elongate energy-absorbing elements 3, 4 are each fitted on their respective side of a central longitudinal axis 6 of the vehicle 1. They are otherwise of substantially identical construction. The first elongate energy-absorbing element 3 has an extent between a first connection 3 a to the beam element 2 and a second connection 3b to an end portion of a first longitudinal side-member 7a of the heavy vehicle 1. The second elongate energy-absorbing element 4 has an extent between a first connection 4a to the beam element 2 and a second connection 4b to an end portion of a second longitudinal side-member 7b of the heavy vehicle 1. In this case the first connections 3 a, 4a are fixed, while the second connections 3b, 4b are pivotable.

The energy-absorbing elements 3, 4 are so constructed that they are intended to become deformed when subjected to a collision force 5 exceeding a certain value. The energy-absorbing elements 3, 4 are intended substantially to become deformed in a certain direction 3 c, 4c in order to absorb kinetic energy in a desired manner. The intended direction of deformation 3c, 4c is here parallel with the longitudinal direction of the elongate energy-absorbing elements 3, 4. For the energy-absorbing elements 3, 4 to become deformed in said direction 3 c, 4c requires the direction of the collision force 5 not to differ too greatly from the directions of deformation 3c, 4c. The construction of the energy-absorbing elements 3, 4 is such that the direction of the collision force 5 may not differ by more than a certain angle relative to the directions of deformation 3c, 4c if a desired deformation is to be achieved. This angle α can be determined with a relatively great degree of accuracy. Each of the energy-absorbing elements 3, 4 can therefore provide controlled deformation within its respective well- defined angle range Ai, A . If the direction of the collision force 5 is outside said angle ranges Ai, A₂, the energy- absorbing elements 3, 4 will break without substantially any kinetic energy being absorbed.

In Fig. 1, the first and second energy-absorbing elements 3, 4 are fitted at an angle of 2α to one another and at an angle of α to the vehicle's longitudinal axis 6. They thus each have their respective angle ranges Ai, A₂ adjoining one another close to the longitudinal axis 6. Said angle ranges Ai, A₂ form together a relatively large combined angle range within which controlled energy absorption is possible when a passenger vehicle collides with the heavy vehicle 1. When such a collision occurs, one of the energy-absorbing elements 3, 4 will always become deformed in an energy-absorbing manner while the other energy-absorbing element 3, 4 breaks without substantially any energy being absorbed. A predetermined absorption of kinetic energy which is substantially independent of the angle of collision between the passenger vehicle and the heavy vehicle 1 is thus provided within said combined angle range. The magnitude of said predetermined absorption of kinetic energy is adapted providing to substantially optimum protection against the risk of harm to persons in a passenger vehicle which collides with the heavy vehicle 1.

Fig. 2 depicts underrun protection which comprises four energy-absorbing elements 3, 4. In this case a first energy-absorbing element 3 and a second energy-absorbing element 4 are arranged in pairs on different sides of the vehicle's central longitudinal axis 6. One pair of energy-absorbing elements 3, 4 is therefore provided with second connections 3 b, 4b to the first longitudinal side-member 7a. The second pair of energy-absorbing elements 3, 4 is correspondingly provided with second connections 3b, 4b to the second longitudinal side-member 7b. The energy-absorbing elements 3, 4 have first connections 3 a, 4a to the beam element 2. Here again the first energy- absorbing elements 3 and the second energy-absorbing elements 4 are fitted in such a way that they are at an angle of 2α to one another and an angle of α to the vehicle's longitudinal axis 6. The first energy-absorbing elements 3 and the second energy- absorbing elements 4 thus here again form mutually adjoining angle ranges Ai, A₂. They thus form a corresponding combined angle range comprising the aggregate of the first angle range Ai and the second angle range A₂. When a passenger vehicle collides with the heavy vehicle 1 at an angle which falls within said combined angle range, the two first energy-absorbing elements 3 or the two second energy-absorbing elements 4 will always become deformed in an energy-absorbing manner while the other two energy-absorbing elements 3, 4 break without substantially any energy being absorbed. Here again, absorption of a certain amount of kinetic energy within said combined angle range is provided to an extent such as to provide substantially optimum protection against the risk of harm to passengers in the passenger vehicle. As two energy-absorbing elements 3, 4 are here used for absorbing kinetic energy during the collision, their construction is weaker than that of the energy-absorbing elements 3, 4 in the embodiment of Fig. 1.

Fig. 3 depicts underrun protection which likewise comprises four energy-absorbing elements 3, 3', 4, 4'. In this case, however, the energy-absorbing elements 3, 3', 4, 4' are fitted to the vehicle 1 in such a way as to provide four different directions of deformation 3c, 3'c, 4c, 4'c. The energy-absorbing elements 3, 3', 4, 4' are fitted symmetrically relative to the vehicle's central longitudinal axis 6. The energy- absorbing elements 3, 3', 4, 4' are fitted at an angle of α to adjoining energy- absorbing elements 3, 3', 4, 4'. They thus form angle ranges Ai, A₂, A₃, A₄ which successively overlap one another. The overlapping angle ranges form a larger combined angle range bounded by the outer energy-absorbing elements 3', 4'. When a passenger vehicle collides with the heavy vehicle 1 at an angle which falls within said combined angle range, two adjoining energy-absorbing elements 3, 3', 4, 4'. will always become deformed in an energy-absorbing manner while the other two energy- absorbing elements 3, 4 break without substantially any energy being absorbed.

In this case the beam element 2 is provided with an external concave curved surface adapted to constituting a contact surface with a colliding object. The contact surface may here be at substantially a right angle to a collision force 5 and the direction of deformation 3 c, 3'c, 4c, 4'c of the energy-absorbing element. Such a curved beam element 2 provides controlled transmission of the collision force 2 to the energy- absorbing elements 3, 3', 4, 4'. The beam element 2 also has on the inside a surface with a substantially corresponding curved shape.

The invention is in no way limited to the embodiment described but may be varied freely within the scopes of the claims. The protection device thus need not be underrun protection applied to the front of a heavy vehicle but may be applied to the rear or a long side of the vehicle. Nor is it limited to being underrun protection but may be used as a protection device of substantially any desired kind on a vehicle, e.g. a bumper. The number of energy-absorbing elements may of course be varied as desired, as also the shape of the beam element.

Claims

1. A protection device for a vehicle whereby the protection device comprises a beam element (2) adapted to being subjected to a collision force (F) when an object collides with the vehicle (1), and at least two energy-absorbing elements (3, 4), each of which has a connection (3a, 4a) with the beam element (2), whereby the construction of the energy-absorbing elements (3, 4) is such that they become deformed in an energy- absorbing manner when subjected to a collision force (F) exceeding a certain value and acting in a direction which is within a defined angle range (Ai, A₂) relative to an intended direction of deformation (3 c, 4c) of the respective energy-absorbing elements (3, 4), and that they become deformed without substantially any energy being absorbed when subjected to a collision force (F) exceeding said certain value and acting in a direction which is outside said angle range (Ai, A₂), characterised in that the energy- absorbing elements (3, 4) are fitted to the vehicle in such a way that their respective directions of deformation (3 c, 4c) are at an angle to one another.

2. A protection device according to claim 1, characterised in that the energy-absorbing elements (3, 4) are fitted to the vehicle in such a way that their respective angle ranges (Ai, A₂) adjoin one another.

3. A protection device according to claim 1 or 2, characterised in that the first and second energy-absorbing elements (3, 4) are fitted to the vehicle in such a way that their angle ranges (Ai, A ) at least partly overlap one another.

4. A protection device according to any one of the foregoing claims, characterised in that the protection device comprises substantially any desired number of energy- absorbing elements (3, 3', 4, 4') fitted to the vehicle in such a way that their angle ranges (Ai, A₂, A₃, A ) together form a combined angle range within which a certain number of the energy-absorbing elements (3, 3', 4, 4') always become deformed in an energy-absorbing manner while the other energy-absorbing elements (3, 3', 4, 4') become deformed without substantially any energy being absorbed.

5. A protection device according to claim 4, characterised in that the protection device comprises four energy-absorbing elements (3, 3', 4, 4') fitted to the vehicle in such a way that their angle ranges (A., A₂, A₃, A ) together form a combined angle range within which two of the energy-absorbing elements (3, 3', 4, 4') become deformed in an energy-absorbing manner while the other two energy-absorbing elements (3, 3', 4, 4') become deformed without substantially any energy being absorbed.

6. A protection device according to any one of the foregoing claims, characterised in that the beam element (2) is of substantially rigid construction.

7. A protection device according to any one of the foregoing claims, characterised in that the beam element (2) has an external contact surface (2a) with a convex curved shape.

8. A protection device according to any one of the foregoing claims, characterised in that the energy-absorbing elements (3, 3', 4, 4') are connected to a rigid element (7a, b) of the vehicle.

9. A protection device according to claim 8, characterised in that said rigid element is a longitudinal side-member (7a, b) of the vehicle.

10. A protection device according to any one of the foregoing claims, characterised in that the protection device is a form of underrun protection.