WO2007067121A1

WO2007067121A1 - An air-bag arrangement

Info

Publication number: WO2007067121A1
Application number: PCT/SE2006/001340
Authority: WO
Inventors: Martin Östling; Mats Erlingfors; Hans Liljeberg
Original assignee: Autoliv Development Ab; Ford Global Technologies Llc
Priority date: 2005-12-09
Filing date: 2006-11-28
Publication date: 2007-06-14
Also published as: JP2012126400A; JP2009518232A; DE112006003329T5; DE112006003329B4; GB2433055A; GB0525132D0

Abstract

An air-bag arrangement (7) mounted in a motor vehicle (1 ) having a bonnet (5). The air-bag arrangement (7) comprises an air-bag module (13) which is mounted to the underside of a rear part of the bonnet (5) and connected to a gas generator (11 ). The air-bag arrangement (7) is configured to be actuated in response to an anticipated impact and/or an actual impact with a pedestrian (9). The gas generator (11 ), when actuated, supplies gas to the air-bag module (13) and an air-bag 21 inflates outwardly from the air-bag module (13). The air-bag (21 ) acts as a lifting device as it inflates to lift he rear part of the bonnet (5). As the air-bag (21) inflates the air-bag extends rearwardly to cover part of the windscreen (2) of the vehicle (1 ) and at least part of one of an A post (3) of the vehicle (1 ) to provide a cushion to minimise the chances of a pedestrian (9) striking the part of the windscreen (2) or the A post (3) and facing injury.

Description

AN AIR-BAG ARRANGEMENT

Description of Invention

THE PRESENT INVENTION relates to an air-bag arrangement, and more particularly relates to an air-bag arrangement mounted in a motor vehicle to provide protection for a pedestrian impacting the vehicle in an accident situation.

It has been observed that if a motor vehicle impacts with a pedestrian the bumper of the vehicle often strikes the legs or lower torso of the pedestrian, resulting in the legs of the pedestrian being pushed in the direction of travel of the vehicle, and the head of the pedestrian being tilted towards the bonnet and windscreen of the vehicle. This tilting movement often causes the head or upper torso of the pedestrian to strike the windscreen or one of the A pillars of the vehicle at speed, potentially injuring the pedestrian.

It has been proposed previously to provide an air-bag beneath the rear part of the bonnet of a vehicle and adapt the rear part of the bonnet to be able to be raised relative to the engine block of the vehicle. In the event that the vehicle is involved in a collision with a pedestrian, the rear part of the bonnet is raised and the air-bag is inflated. Once the air-bag has been inflated the air-bag provides a cushion beneath the rear part of the bonnet to absorb energy from the pedestrian as the torso of the pedestrian impacts with the top of the bonnet. The inflated air-bag also extends outwardly from the rear of the bonnet, to cover a part of the windscreen and part of the A pillars of the vehicle. The air-bag thus also provides a cushion which minimises the chances of the head or torso of the pedestrian striking the windscreen or A pillars of the vehicle, thus minimising the injury to the pedestrian. Such a prior proposed arrangement is disclosed in European Patent Application No.

EP-A-0967128. In the prior proposed arrangement of the type discussed above the positioning of the air-bag before inflation is often not optimised to allow quick and reliable inflation of the air-bag so that at least a part of the air-bag covers part of the windscreen or the A pillars of the vehicle.

The present invention seeks to provide an improved air-bag arrangement.

According to one aspect of the present invention, there is provided an air-bag arrangement mounted in a motor vehicle having a bonnet, the air-bag arrangement comprising an air-bag which is connected to be inflated by a source of gas, at least part of the air-bag arrangement being mounted to the underside of a rear part of the bonnet, wherein, on actuation of the air-bag arrangement, the rear of the bonnet is lifted and the air-bag is inflated to cover at least part of the windscreen of the motor vehicle characterised in that each of the said air-bag modules may be actuated independently of the other such that one of the air-bag modules may be actuated to inflate an air-bag on an appropriate side of the vehicle. Preferably the air-bag arrangement further comprises a sensor to sense an anticipated impact with a pedestrian and/or sense an actual impact with a pedestrian and provide a crash signal to actuate the inflation of the air-bag.

Conveniently the rear part of the bonnet is adapted to be raised, on generation of the crash signal, to move the part of the air-bag arrangement which is mounted to the bonnet to a higher position to facilitate coverage of at least part of the windscreen by the air-bag when the air-bag inflates.

In one embodiment the air-bag exerts an upward force on the underside of the bonnet as the air-bag inflates to lift the rear part of the bonnet. In another embodiment the arrangement further comprises a lifter operable to lift the rear part of the bonnet, and wherein the lifter lifts the rear part of the bonnet, on generation of the crash signal, and the air-bag is inflated. Preferably the arrangement further comprises a control unit incorporating a timer which is configured to allow the air-bag to inflate only after a predetermined length of time has elapsed following the initiation of the lifting of the rear part of the bonnet by the lifter. Conveniently the air-bag is initially folded within an air-bag module, the air-bag module being provided with a mounting plate to mount the air-bag module to the underside of the rear part of the bonnet, the air-bag module having a face which, when the air-bag module is mounted in position on the bonnet, faces substantially towards the windscreen of the motor vehicle, the said face of the air-bag module being provided with a weakened section which is configured to rupture upon inflation of the air-bag to define an opening to allow the air-bag to inflate outwardly from the opening to cover at least part of the windscreen.

Advantageously the arrangement comprises two air-bags which are each initially folded within respective air-bag modules which are mounted to the underside of the bonnet and positioned respectively on each side of the bonnet, such that each air-bag, when inflated, covers at least part of one side of the windscreen of the motor vehicle and/or at least part of one of the A posts of the motor vehicle.

According to another aspect of the invention, there is provided an air-bag arrangement comprising an air-bag which is connected to be inflated by a source of gas, at least part of the air-bag being mounted to a part of a bonnet which is to be the part of the bonnet which is closest to the windscreen of a motor vehicle when the bonnet is mounted to a motor vehicle. In order that the invention may be more readily understood, and so that further features thereof may be appreciated, the invention will now be described, by way of example, with reference to the accompanying drawings in which: FIGURE 1 is a diagrammatic sectional view of an air-bag arrangement in accordance with a preferred embodiment of the invention mounted in a motor vehicle, in an un-actuated condition,

FIGURE 2 is a diagrammatic view from beneath of a bonnet incorporating an air-bag arrangement in accordance with the preferred embodiment of the invention,

FIGURE 3 is a view corresponding to Figure 1 with the arrangement having been actuated, and

FIGURE 4 is a diagrammatic sectional view of an air-bag arrangement in accordance with an alternative embodiment of the invention mounted in a motor vehicle, in an un-actuated condition. Referring initially to Figures 1 and 2 of the accompanying drawings, a motor vehicle 1 has a windscreen 2 which is held in position on each side by a respective A post 3 which forms part of the chassis of the vehicle 1. A scuttle 4 is provided along the lower edge of the windscreen 2 to collect rain water flowing off the windscreen 2, and to direct the rain water away from the engine of the vehicle 1. The engine of the vehicle 1 is covered by a bonnet 5. The bonnet 5 extends from a position above the scuttle 4 towards the front of the vehicle where it is held in place by a catch 6. It is to be appreciated that the catch 6 may be released to allow the front part of the bonnet 5 to be lifted to allow maintenance to occur to the engine. The catch 6 is also configured to retain the front part of the bonnet 5 in connection with the front part of the vehicle 1 in a situation where the rear part of the bonnet 5 is lifted. The rear part of the bonnet 5 is attached to the vehicle 1 by a pivoting mechanism (not shown for simplicity purposes), such as one or more hinges, which allows the bonnet 5 to undergo a pivoting movement when the front part of the bonnet 5 is lifted to allow maintenance to the engine. The pivoting mechanism is also configured to allow the rear part of the bonnet 5 to be lifted in the event that an accident situation occurs, as will be explained in more detail below.

An air-bag arrangement 7 in accordance with a preferred embodiment of the invention is mounted in the vehicle 1. The air-bag arrangement 7 comprises a sensor 8 which is mounted to a front part of the vehicle 1. The sensor 8 is a sensor which is configured to provide a crash signal indicative of an anticipated impact with a pedestrian 9 and/or an actual impact with a pedestrian 9. The sensor 8 is connected to provide said crash signal to a control unit 10.

The control unit 10 is connected to provide an actuation signal to two gas generators 11 which are mounted to the underside of a rear part of the bonnet 5 on each side of the bonnet 5. The gas generators 11 are connected via tubes 12 to supply gas to a respective one of two air-bag modules 13 which are mounted to each side of the underside of the rearmost part of the bonnet 5, lying above and partly overlapping with the scuttle 4.

The gas generator 11 , tube 12 and air-bag module 13 mounted to the underside of one side of the bonnet 5 is identical to the gas generator 11 , tube 12 and air-bag module 13 which is mounted to the underside of the other side of the bonnet 5. Therefore, for the purposes of simplicity, only one gas generator 11 , tube 12 and air-bag module 13 will be referred to in the following description.

The upper surface of the air-bag module 13 is defined by a substantially rigid mounting plate 14 which enables the air-bag module 13 to be securely mounted to the underside of the bonnet 5. The air-bag module 13 has respective front and rear walls 15,16 and side wails 17,18 which depend downwardly from the mounting plate 14 to a lower plate 19 which defines the underside of the air-bag module 13. The front and rear walls 15,16 and the side walls 17,18 are formed of a resilient material. The rear wall 16 defines a face which, when the air-bag module 13 is mounted to the bonnet 5, faces substantially towards the windscreen 2. The rear wall 16 is provided, along its length, with a horizontal weakened section in the form of a split line 20. The purpose of the split line 20 will become clear from the description.

In the event that the sensor 8 senses an anticipated impact with the pedestrian 9 or an actual impact with the pedestrian 9, the sensor 8 sends a crash signal to the control unit 10. The control unit 10 processes the crash signal and generates an actuation signal which is transmitted to the gas generator 11. The actuation signal actuates the gas generator 11 and the gas generator injects gas into the air-bag module 13.

When gas is injected into the air-bag module 13 an air-bag 21, which is initially folded within the air-bag module 13, starts to inflate. The inflating air-bag 21 exerts a force on the walls 14-19 of the air-bag module 13, and the force on the rear wall 16 causes the rear wall 16 to rupture along the split line 20. As the split line 20 splits the inflating air-bag 21 pushes the rear edge of the lower wall 19 away from the upper mounting plate 14, and as the walls 14-19 of the air-bag module 13 are of a resilient material, the rear and side walls 15,17,18 deform to allow the rear wall 16 to open up. The opening in the rear wall 16 allows the air-bag 21 to inflate outwardly from the air-bag module 13 in a direction towards the windscreen 2, as seen in Figure 3.

As the air-bag 21 inflates outwardly from the air-bag module 13 the material of the air-bag 21 exerts a force on the scuttle 4 and the lower part of the windscreen 2. The force on the scuttle 4 and the windscreen 2 creates a reactive force which has an upward component that pushes the rear part of the bonnet 5 upwardly. The upward force created by the inflating air-bag 21 raises the rear part of the bonnet 5 and the air-bag 21 thus acts as a lifting device to lift the rear part of the bonnet 5. The bonnet 5 pivots about the front catch 6 as the rear of the bonnet 5 is lifted by the air-bag 21. The mounting plate 14 of the air-bag module 13 which forms part of the air-bag arrangement which is mounted to the underside of the bonnet 5 is moved to a higher position as the rear part of the bonnet 5 is lifted by the air-bag 21. The higher position of the air-bag module 13 facilitates the inflation of the air-bag 21 to cover part of the windscreen 2 and at least one of the A posts 3.

Once the air-bag 21 has fully inflated the air-bag 21 defines a cushioning element which supports the rear part of the lifted bonnet so that if the pedestrian 9 is thrown onto the bonnet 5 the air-bag 21 absorbs energy from the bonnet 5 as the bonnet 5 is pushed down by the torso of the pedestrian 9. This cushioning effect provided by the air-bag 21 absorbs energy as the bonnet 5 is pushed downwardly by the pedestrian 9, and acts to minimise the possibility of the pedestrian 9 being injured as a result of being rapidly decelerated when striking the bonnet 5.

In addition to providing the cushioning effect beneath the rear part of the bonnet 5, the air-bag 21 also provides a cushion which covers the lower part of the windscreen 2 and the lower part of one of the A pillars 3. The cushioning cover provided by the air-bag 21 acts to minimise the chances of the head or upper torso of the pedestrian 9 striking the lower part of the windscreen 2 or one of the A posts 3 at speed, potentially causing injury to the pedestrian 9. It is to be appreciated that in this preferred embodiment of the invention the respective air-bag modules 13 mounted to each side of the rear part of the bonnet 5 are actuated simultaneously by the control unit 10 to allow respective air-bags 21 to inflate from the air-bag modules 13 to cover part of the windscreen 2 and a respective A post 3 on corresponding sides of the vehicle.

In other embodiments of the invention the air-bag modules 13 on each side of the bonnet 5 can be actuated independently of one another by the control unit 10. In such embodiments the sensor 8 is a sensor is capable of sensing the position along the front of the vehicle which is anticipated to impact or which actually impacts the pedestrian 9. The sensor 8 transmits a crash signal to the control unit 10 which is indicative of the side of the vehicle on which the impact is occurring or about to occur. The control unit 10 is configured to process the crash signal and actuate the air-bag module 13 on the same side of the vehicle as the impact or anticipated impact so that injury to the pedestrian 9 from striking the part of the windscreen or the A post on the side of the vehicle where the impact occurs is minimised. In this case, only one of the two air-bag modules 13 is actuated to offer protection to the pedestrian 9, and thus only the actuated air-bag module 13 must be replaced following the impact.

It is also envisaged that a single air-bag module may be provided, and in these embodiments the single air-bag should be at least approximately centrally mounted on the underside of the rear part of the bonnet.

Referring now Figure 4 of the accompanying drawings, an air-bag arrangement 7 in accordance with an alternative embodiment of the invention is mounted in a motor vehicle 1. The air-bag arrangement 7 of this alternative embodiment is identical to the air-bag arrangement 7 of the preferred embodiment described above, but the air-bag arrangement 7 of this alternative embodiment incorporates a bonnet lifter 22. One end of the bonnet lifter 22 is mounted to the underside of the rearmost part of the bonnet 5 and the other end of the bonnet lifter 22 is mounted to part of the vehicle 1 which is connected to the scuttle 4 or to another appropriate part of the chassis of the motor vehicle 1. The bonnet lifter 22 is connected to receive a lifting signal from the control unit 10.

In the event that the sensor 8 senses an anticipated impact with a pedestrian 9 or an actual impact with the pedestrian 9 the sensor sends a crash signal to the control unit 10. The control unit 10 processes the crash signal and transmits a lifting signal to the bonnet lifter 22 and an actuation signal to the gas generator 11. When the bonnet lifter 22 receives the lifting signal the bonnet lifter 22 is actuated to lift the rear part of the bonnet 5 to move the air-bag module 13 to a higher position to facilitate inflation of the air-bag 21 to cover part of the windscreen 2 and at least one of the A posts 3.

In other embodiments of the invention the control unit 10 may incorporate a timer 23 which is configured to allow the control unit 10 to transmit the actuation signal to the gas generator 11 only after a predetermined length of time has elapsed following the transmission of the lifting signal to the bonnet lifter 22. The timer 23 thus provides a delay which ensures that the air-bag 21 is only inflated outwardly from the air-bag module 13 when a predetermined time has elapsed, which may be the time taken for the bonnet lifter 22 to raise the rear part of the bonnet 5, to raise the air-bag module 13 to the higher position.

In yet further embodiments of the invention the tube 12 may be omitted and the gas generator 11 may be formed integrally as part of the air-bag module 13.

When used in this specification and claims, the terms "comprises" and "comprising" and variations thereof mean that the specified features, steps or integers are included. The terms are not to be interpreted to exclude the presence of other features, steps or components.

Claims

1. An air-bag arrangement (7) mounted in a motor vehicle (1) having a bonnet (5), the air-bag arrangement (7) comprising an air-bag (13) which is connected to be inflated by a source of gas (11), at least part of the air-bag arrangement (7) being mounted to the underside of a rear part of the bonnet (5), wherein, on actuation of the air-bag arrangement (7), the rear of the bonnet (5) is lifted and the air-bag (21 ) is inflated to cover at least part of the windscreen (2) of the motor vehicle (1) characterised in that each of the said air-bag modules (13) may be actuated independently of the other such that one of the air-bag modules (13) may be actuated to inflate an air-bag (21) on an appropriate side of the vehicle (1).

2. An air-bag arrangement (7) according to Claim 1, further comprising a sensor (8) to sense an anticipated impact with a pedestrian and/or sense an actual impact with a pedestrian and provide a crash signal to actuate the inflation of the air-bag (21).

3. An air-bag arrangement (7) according to Claim 2, wherein the rear part of the bonnet (5) is adapted to be raised, on generation of the crash signal, to move the part of the air-bag arrangement (7) which is mounted to the bonnet (5) to a higher position to facilitate coverage of at least part of the windscreen (2) by the air-bag (21) when the air-bag (21) inflates.

4. An air-bag arrangement (7) according to Claim 3, wherein the air- bag (21 ) exerts an upward force on the underside of the bonnet (5) as the air- bag (21 ) inflates to lift the rear part of the bonnet (5).

5. An air-bag arrangement (7) according to Claim 3, further comprising a lifter (22) operable to lift the rear part of the bonnet (5), and wherein the lifter (22) lifts the rear part of the bonnet (5), on generation of the crash signal, and the air-bag (21) is inflated.

6. An air-bag arrangement (7) according to Claim 5, further comprising a control unit (10) incorporating a timer (23) which is configured to allow the air- bag (21) to inflate only after a predetermined length of time has elapsed following the initiation of the lifting of the rear part of the bonnet (5) by the lifter (22).

7. An air-bag arrangement (7) according to any one of the preceding Claims, wherein the air-bag (21) is initially folded within an air-bag module (13), the air-bag module (13) being provided with a mounting plate (14) to mount the air-bag module (13) to the underside of the rear part of the bonnet (5), the air-bag module (13) having a face which, when the air-bag module (13) is mounted in position on the bonnet (5), faces substantially towards the windscreen (2) of the motor vehicle (17), the said face of the air- bag module (13) being provided with a weakened section (20) which is configured to rupture upon inflation of the air-bag (21) to define an opening to allow the air-bag (21) to inflate outwardly from the opening to cover at least part of the windscreen (2).

8. An air-bag arrangement (7) according to any one of the preceding Claims comprising two air-bags (21) which are each initially folded within respective air-bag modules (13) which are mounted to the underside of the bonnet (5) and positioned respectively on each side of the bonnet (5), such that each air-bag (21), when inflated, covers at least part of one side of the windscreen (2) of the motor vehicle (1) and/or at least part of one of the A posts (3) of the motor vehicle (1 ).