WO2014137252A1

WO2014137252A1 - A safety arrangement for a vehicle

Info

Publication number: WO2014137252A1
Application number: PCT/SE2013/050189
Authority: WO
Inventors: Erik Neander; Alf Holgers; Rickard Andersson
Original assignee: Autoliv Development AB
Current assignee: Autoliv Development AB
Priority date: 2013-03-04
Filing date: 2013-03-04
Publication date: 2014-09-12
Anticipated expiration: 2015-09-04

Abstract

The present invention relates to a vehicle collision safety arrangement (23) comprising a vehicle structural component (5, 6) which has a longitudinal extension (L) extending between a first end (18) and a second end (19). The structural component (5, 6) has a first surface (20) and a second surface (21), the first end (18) being attached to a first part (7, 8) and the second end (19) being attached to a second part (2). Amain aperture (9) extends between the first surface (20) and the second surface (21), where a piece of material (10) is fit into the main aperture (9). The safety arrangement (23) further comprises a housing (12a, 12b) attached to the second surface (21), where the housing (12a, 12b) comprises a piston arrangement (13, 14) and a pyrotechnical charge (15). When detonated (25), the pyrotechnical charge (15) is arranged to propel the piston arrangement (13, 14) in relation to the piece of material (10) such that the piece of material (10) is removed from the main aperture (9).

Description

TITLE

A safety arrangement for a vehicle DESCRIPTION OF THE INVENTION

The present invention relates to a vehicle collision safety arrangement comprising a vehicle structural component which has a longitudinal extension extending between a first end and a second end. The structural component has a first surface and a second surface, the first end being attached to a first part and the second end being attached to a second part.

In the design of motor vehicles the energy absorption characteristics of the vehicle structure during an impact event is an important consideration. During an impact event, vehicle occupants are subjected to crash loads that may cause severe injuries. Such crash loads are for instance the result of high acceleration during the impact event. The level of acceleration that the occupants are subjected to during an impact event is highly influenced by the stiffness of the vehicle structure.

It is well known to define certain deformation zones that are adapted to absorb collision energy in order to reduce the acceleration levels experienced by the occupants and thereby reduce the risk of injuries to the occupants. By absorbing a substantial amount of collision energy, the occupants are subjected to a lower acceleration during the impact event. One way to create deformation zones is to weaken structural members such as beams or link arms, allowing these parts to bend and to absorb energy more easily in the event of an impact. It is also desired to have holding members that deform such that parts in a deformation zone, such as an engine, is allowed to follow the deformation path, increasing the deformation energy absorbing effect.

US 6113178 discloses a pyrotechnic device arranged to generate combustion products and to direct said combustion products into engagement with a structural member, to weaken said structural member, and thereby to enable controlled deformation of said structural member. For example, the combustion products may remove a part of a beam, the part for example being pre-weakened.

However, such an arrangement, where pyrotechnical charges more or less are mounted to structural members, is highly unreliable, and might even be dangerous. The use of pre- weakened parts according to US 6113178 also creates a degree of unreliability, these parts always providing a lower degree of structural rigidity.

There is thus a need for an improved such arrangement.

It is an object of the present invention to provide an arrangement that is adapted to weaken a structural vehicle part in the event of a collision, the weakening being made in a controlled and efficient way, where the structural vehicle part has a normal degree of structural rigidity before the weakening takes place.

Said object is achieved by means of a vehicle collision safety arrangement comprising a vehicle structural component which has a longitudinal extension extending between a first end and a second end. The structural component has a first surface and a second surface, the first end being attached to a first part and the second end being attached to a second part. A main aperture extends between the first surface and the second surface, where a piece of material is fit into the main aperture. The safety arrangement further comprises a housing attached to the second surface, the housing comprising a piston arrangement and a pyrotechnical charge. When detonated, the pyrotechnical charge is arranged to propel the piston arrangement in relation to the piece of material such that the piece of material is removed from the main aperture.

According to an example, the pyrotechnical charge is arranged to propel the piston arrangement towards and against the piece of material, such that the piece of material is removed from the main aperture.

Alternatively, the pyrotechnical charge is arranged to propel the piston arrangement from the piece of material, the piston arrangement at least during a part of its motion being arranged to engage and bring the piece of material with it.

According to another example, the structural component is arranged to be weakened by means of the removal of said piece of material, such that deformation of the structural component is facilitated.

According to another example, the piston arrangement comprises a piston and a piston rod.

Other examples are disclosed in the dependent claims.

The present invention has a number of advantages. For example:

- A structural component may have a normal rigidity during normal condition and may be weakened in a controlled manner . - The weakening mechanism may easily be made to be detachable .

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described more in detail with reference to the appended drawings, where

Figure 1 shows a schematical side view of a vehicle equipped with the safety arrangement according to the present invention;

Figure 2 shows a schematical bottom view of a front part of the vehicle before collision; Figure 3 shows a schematical perspective view of a link arm;

Figure 4 shows a schematical partly cut-open side view of a link arm in a first state; Figure 5 shows a schematical partly cut-open side view of a link arm in a second state;

Figure 6 shows a schematical partly cut-open side view of a link arm in a third state;

Figure 7 shows a schematical bottom view of a front part of the vehicle after collision;

Figure 8 shows a schematical partly cut-open side view of a first alternative link arm in the first state;

Figure 9 shows a schematical partly cut-open side view of a second alternative link arm in a first state; Figure 10 shows a schematical partly cut-open side view of a second alternative link arm in a second state; and

Figure 11 shows a schematical partly cut-open side view of a second alternative link arm in a third state.

DETAILED DESCRIPTION

With reference to Figure 1, showing a side view of a vehicle 1, and Figure 2, showing a bottom view of a front part of the vehicle 1, the vehicle 1 comprises an engine assembly 2 that is connected to first holding arm 3 on a first side and a second holding arm 4 on a second side. Each holding arm 3, 4 is in turn connected to a corresponding first link arm 5 and second link arm 6. Each link arm 5, 6 connects the corresponding holding arm 3 to a corresponding beam part 7, 8. The beam parts 7, 8 are laterally placed structural elements that run along the vehicles longitudinal extension L.

In this way, the engine assembly is connected to the beam parts 7, 8 via the holding arms 3, 4 and the link arms 5, 6.

Figure 3 shows the first link arm 5, which has a longitudinal extension L extending between a first end 18 and a second end 19. The first link arm has a first surface 20 and a second surface 21, and a thickness 22 separating the two surfaces 20, 21. The thickness 22 is here shown to be of a constant value, but may vary. The surfaces 20, 21 are shown to run in one plane, but may have one or more bends. In this example, the first end 18 is attached to the corresponding beam structure 7 in the vehicle 1, and the second end 19 is attached to the engine assembly 2.

According to the present invention, a part of the material has been removed from the link arm 5, such that a trough-hole 9 is created, running through the first link arm between the two surfaces 20, 21. Here, a cylindrical piece 10 has been removed, and then inserted into the through-hole 9 again, as shown in Figure 4.

As shown in a partly cut-open view in Figure 4, a plunger unit 11 is mounted to the first link arm 5, the plunger unit 11 comprising a housing 12a, a piston 13, a piston rod 14 and a pyrotechnical charge 15. The piston 13 and the piston rod 14 are movable in a cavity 26 in the housing 12a. As shown in Figure 5, in the case of a collision, the pyrotechnical charge 15 is detonated 25, the explosion gases driving the piston 13 and the piston rod 14 towards the cylindrical piece 10, pressing it away from its position in the first link arm 5.

As shown in Figure 6, the cylindrical piece 10 has been pressed away from the first link arm 5, leaving the first link arm 5. Only the piston rod 14, having a smaller cross- sectional area than the cylindrical piece 10, remains in the through-hole 9. In this way, the first link arm 5 has been weakened, allowing a bend or any other type of deformation of the first link arm 5 to be performed more easily than before. A similar arrangement is positioned at the second link arm 6, both link arms 5, 6 being arranged to be weakened in the way described in the case of a collision. As indicated in Figure 2 and Figure 7, a corresponding housing 12b is positioned on the second link arm 6.

As shown in Figure 7, corresponding to Figure 2, a collision has occurred as indicated by an arrow 27, and the front of the vehicle 1 has been deformed 16, 17. The link arms 5, 6 have been weakened in the way described above, and have been bent in such a way that the engine assembly 2 has been allowed to move relative the beam parts 7, 8, towards the back of the vehicle 1. In this way, collision energy has been absorbed, and thus the person or persons in the vehicle have been relieved of the absorbed amount of collision energy. Generally, the present invention relates to a vehicle collision safety arrangement 23 comprising a vehicle structural component 5, 6 which has a longitudinal extension L extending between a first end 18 and a second end 19. The structural component 5, 6 has a first surface 20 and a second surface 21, the first end 18 being attached to a first part 3 and the second end 19 being attached to a second part 7. A main aperture 9 extends between the first surface 20 and the second surface 21, where a piece of material 10 is fit into the main aperture 9.

The safety arrangement further comprises a housing 12a, 12b attached to the second surface 21, the housing 12a, 12b comprising a piston arrangement 13, 14 and a pyrotechnical charge 15. When detonated, the pyrotechnical charge 15 is arranged to propel the piston arrangement 13, 14 towards and against the piece of material 10 such that the piece of material 10 is removed from the main aperture 9. The piston arrangement 13, 14 may comprise one part or several parts, as the described piston 13 and piston rod 14.

The present invention is not limited to the examples above, but may vary within the scope of the appended claims. For example, as shown in Figure 8 showing a first alternative safety arrangement 23' with an alternative plunger unit 11', an alternative piston rod 14' may be spring-loaded by means of a helical spring 24. After the removal of the cylindrical piece 10 from the link arm 5, the piston rod 14' will be retuned into the housing 12a by means of the spring force. In this way, the piston rod's 14' size is not as important, since its return will prevent in from interfering with the deformation of the link arm 5. Any type of return mechanism is of course conceivable, the spring 24 only being an example. As shown in a partly cut-open view in Figure 9, showing a second alternative safety arrangement 23' ' , a plunger unit 11'' is mounted to a first link arm 5^{' '}, which first link arm 5^{' '} has a longitudinal extension L extending between a first end 18'' and a second end 19'' . The first link arm 5'' has a first surface 20'' and a second surface 21'', and a thickness 22'' separating the two surfaces 20'', 21'' . The thickness 22'' is here shown to be of a constant value, but may vary. The surfaces 20'', 21'' are shown to run in one plane, but may have one or more bends .

The plunger unit 11'' comprises a housing 12a'', a piston 13'', a piston rod 14'', a rod head 29 and a pyrotechnical charge 15' ' . The piston 13' ' , the piston rod 14 and the piston rod head 29 are movable in first cavity 30 and a second cavity 32 in the housing 12a, a first rod aperture 31 separating the first cavity 30 and second cavity 32. The pyrotechnical charge 15' ' and the piston 13' ' are positioned in the second cavity 32, the piston rod 14'' extending into the first cavity 30 via the first rod aperture 31.

The first cavity comprises an intermediate housing 28 attached to a cylindrical piece 10' ' in a trough-hole 9' ' running through the first link arm 5' ' between the two surfaces 20' ' , 21^{' '} as in the previous examples. The intermediate housing 28 comprises a third cavity, 34 the piston rod 14'' extending into the third cavity 34 via a second rod aperture 33. The rod head 29 is movable within the third cavity 34, normally being positioned away from the second rod aperture 33. It is to be noted that the pyrotechnical charge 15' ' is positioned in the second cavity 32, between the first rod aperture 31 and the piston 13' ' .

As shown in Figure 10, in the case of a collision, the pyrotechnical charge 15' ' is detonated 25' ' , the explosion gases driving the piston 13, the piston rod 14 and the rod head 29 away from the cylindrical piece 10'' . The rod head 29 has moved in the third cavity 34, from its original position towards the second rod aperture 33 such that the piston head 29 exerts a pulling force on the intermediate housing 28 and the cylindrical piece 10' ' .

As shown in Figure 11, the cylindrical piece 10'' has been pulled away from the first link arm 5' ' , leaving the first link arm 5'' and being retained in the first cavity 30. In this way, the first link arm 5' ' has been weakened as in the previous examples. By means of the distance the piston head 29 travels in the third cavity 34, from its original position towards the second rod aperture 33, certain energy has already been built up when a pulling force starts to work on the cylindrical piece 10'', enhancing the removal procedure.

A similar arrangement is positioned at the second link arm 6. Many types of shapes are conceivable for the piece of material 9 that is pressed or pulled out from the link arm. The piece of material may be fit into the through-hole by means of a bushing or similar, preventing the piece of material from getting too stuck in the through-hole, for example by means or rust.

The link arms are only an example; generally any structural component or components may be weakened by means of the present invention. The intention of the weakening, which is performed at the event of a collision, is to allow a larger extent of collision forces to be absorbed. The weakening allows a larger extent of deformation to take place than if a weakening would not have been made. Before the weakening, the structural component has normal rigidity.

The beam parts may be any sort of beam structure. The through- hole is generally a main aperture with a suitable shape.

There may be two or more pieces of material that are arranged to be removed from corresponding apertures in a structural component by means of one or several pyrotechnical charges.

Claims

CLAIMS 1. A vehicle collision safety arrangement (23) comprising a vehicle structural component (5, 6) which has a longitudinal extension (L) extending between a first end (18) and a second end (19), the structural component (5, 6) having a first surface (20) and a second surface (21), the first end (18) being attached to a first part (7, 8) and the second end

(19) being attached to a second part (2), characterized in that a main aperture (9) extends between the first surface

(20) and the second surface (21), where a piece of material (10) is fit into the main aperture (9), the safety arrangement (23) further comprising a housing (12a, 12b) attached to the second surface (21), the housing (12a, 12b) comprising a piston arrangement (13, 14) and a pyrotechnical charge (15), where, when detonated (25), the pyrotechnical charge (15) is arranged to propel the piston arrangement (13, 14) in relation to the piece of material (10) such that the piece of material (10) is removed from the main aperture (9) .

2. A safety arrangement according to claim 1, characterized in that the piston arrangement comprises a piston (13) and a piston rod (14) .

3. A safety arrangement according to any one of the claims 1 or 2, characterized in that the pyrotechnical charge (15) is arranged to propel the piston arrangement (13, 14) towards and against the piece of material (10), such that the piece of material (10) is removed from the main aperture (9) .

4. A safety arrangement according to claim 3, characterized in that the piston rod (14) has a cross-section area that falls below the cross-section area of the main aperture ( 9 ) .

5. A safety arrangement according to any one of the claims 1 or 2, characterized in that the pyrotechnical charge

(15) is arranged to propel the piston arrangement (13, 14, 29) from the piece of material (10''), the piston arrangement (13, 14, 29) at least during a part of its motion being arranged to engage and bring the piece of material (10'') with it.

6. A safety arrangement according to claim 5, characterized in that safety arrangement (23' ' ) comprises an intermediate housing (28) attached to the cylindrical piece (10''), the intermediate housing (28) comprising a third cavity (34), where the piston rod (14'') extends into the third cavity (34) via a second rod aperture (33), and where a rod head (29) comprised in the piston arrangement (13, 14, 29) is movable within the third cavity (34) .

7. A safety arrangement according to any one of the previous claims, characterized in that the structural component (5, 6) is arranged to be weakened by means of the removal of said piece of material (10), such that deformation of the structural component (5, 6) is facilitated.

8. A safety arrangement according to any one of the previous claims, characterized in that the structural component (5, 6) is in the form of a link arm, where its first end (18) is attached to a beam structure (7) in the vehicle.

9. A safety arrangement according to claim 8, characterized in that the second end (19) is attached to an engine assembly (2) .