GB2480798A

GB2480798A - A bonnet for a vehicle

Info

Publication number: GB2480798A
Application number: GB201002775A
Authority: GB
Inventors: Brad Staines; Steve Braybrook
Original assignee: Ford Global Technologies LLC
Current assignee: Ford Global Technologies LLC
Priority date: 2010-02-18
Filing date: 2010-02-18
Publication date: 2011-12-07
Anticipated expiration: 2030-02-18
Also published as: GB2480798B; CN201999075U; GB201002775D0

Abstract

A bonnet 20 for an automotive vehicle 10 is disclosed in which a lock striker 35 is fastened to an inner bonnet panel 22 by means of a bridge like structure. The bridge structure includes a central platform 33 to which the lock striker is fastened, two inclined supports 32 and two feet 31 used to fasten the inclined supports 32 to the inner bonnet panel 22. The bridge spaces the lock striker away from an outer bonnet panel 21 of the bonnet 20 and permits a controlled collapse of the outer bonnet panel 21 towards the lock striker 35 in the event that a pedestrian impacts against the outer bonnet panel 21 in the region of the lock striker 35.

Description

A Bonnet for a Vehicle This invention relates to a bonnet for the front end of an automotive vehicle and in particular to a mechanism connected to the bonnet for securing the bonnet in a closed position.

Motor vehicle manufacturers are constantly striving to provide vehicles which, in the event of a collision, reduce the risk of injury to pedestrians involved in the collision.

Most collisions between vehicles and pedestrians occur in built-up or urban areas in which the speed of the vehicles is relatively low. For example, most jurisdictions impose a speed limit in urban areas of about 50 km/h. In most collisions, the speed of the vehicle is lower than 40 km/h. Due to the relatively light weight of most pedestrians, the amount of energy arising from a low speed collision between a vehicle and a pedestrian is relatively low.

During such a collision between a vehicle and a pedestrian, the pedestrian typically initially impacts the front of the vehicle and, thereafter, the bonnet of the vehicle. Although the bonnet itself may be designed to be relatively deformable, the structure underlying the bonnet may not be so deformable and can constitute a localised hard spot which impacted against by a head of a pedestrian will increase the risk of injury.

One area of concern is that, in case when the hinge mechanism of the bonnet is arranged in the trailing end of the bonnet close to the windscreen of the vehicle, a lock striker will often be arranged in a position close to the leading edge of the bonnet. The lock striker which can be arranged on the inner bonnet to cooperate with a locking mechanism on the vehicle body normally has a relatively hiqh resistance to deformation because of the required rigidity to enable the mechanism to perform its intended function.

Furthermore, when the lock striker is engaged with such a locking mechanism of the vehicle body, the possibility of displacing the lock striker in the vertical direction is very limited. Accordingly, the deformation capability of the bonnet is reduced in the area close to the lock striker.

The bonnet area close to a lock striker is therefore an area of potentially higher risk to a pedestrian hit by a vehicle and in particular to a child, since the head of the child can impact the region of the bonnet where the lock striker is attached.

It has therefore being proposed in EP-A-1557340 to provide a lock striker that is attached to the bonnet by a nut and bolt fixing and includes an engaging portion for engaging with a bonnet lock attached to part of a body structure of the vehicle and two pairs of inclined portions that space the engaging portion from an inner side of the bonnet. The bolts are engaged in slots in a supporting part of the bonnet and are arranged to permit movement between the inclined portions and the supporting part of the bonnet. By spacing the engaging portion away from the outer surface of the bonnet the risk of contact between a pedestrian and the engaging portion is reduced and the nut and bolt fixing allows the structure to collapse when a sufficient load is applied.

There are however several disadvantages with such an arrangement, firstly the projecting bolts themselves form localised hard spots that increase the risk of injury to a pedestrian and secondly the nut and bolt fixing forms a very unreliable method for controlling collapse. That is to say, if the nuts and bolts are not tightened sufficiently the whole assembly could become detached from the bonnet thereby potentially allowing the bonnet to move from its closed position while the vehicle is in motion but if the nuts and bolts are over tightened then the structure may not be able to collapse until an unacceptably high force is applied.

Furthermore, the probable corrosion of the relevant components during the life of the vehicle will make maintenance of the correct clamping force unreliable.

It is an object of this invention to provide a bonnet for an automotive vehicle that will reduce to a substantial extent the risk of injury to a pedestrian during an impact between the pedestrian and a vehicle in a cost effective and reliable manner.

According to a first aspect of the invention there is provided a bonnet for a vehicle having a leading end and a trailing end, the bonnet comprising an outer bonnet panel, an inner bonnet panel fastened to the outer bonnet panel and a lock striker fastened near to one of the leading and trailing ends of the inner bonnet panel for locking the bonnet in a closed position during normal use of the vehicle, the lock striker being fastened to the inner bonnet panel by a transversely extending bridge so that it is arranged in a spaced apart relationship with respect to the inner bonnet panel, wherein the bridge comprises a central platform joined at each end to an inclined support, each of the inclined supports being fastened to the inner bonnet panel by a respective foot so as to prevent relative movement between the respective foot and the inner bonnet panel and the bridge is arranged to collapse in a progressive manner when a force above a predetermined force is applied to it.

Each of the inclined supports may be arranged at an obtuse angle with respect to the platform and at an acute angle with respect to the inner bonnet panel so as to promote the controlled collapse of the bridge.

The bridge may be made from a single piece of material.

Free edges of the platform may have flanges running therealong to increase the resistance to bending of the platform.

The bridge may be made from pressed steel and the free edges of the platform may be bent over to form the flanges.

Free edges of the two inclined supports may have flanges running therealong to increase the resistance to bending of the inclined supports The bridge may be made from pressed steel and the free edges of the two inclined supports may be bent over to form the flanges.

Preferably, no part of the fastening means used to fasten each foot to the inner panel may project towards the outer panel.

Preferably, no part of the fastening means used to fasten the lock striker to the platform may project towards the outer panel.

The bridge may be made from steel, the lock striker may be made from steel and be U-shaped having two legs joined by a common crossbar and the two legs may be fastened to the platform by one of arc welding and projection welding.

The invention will now be described by way of example with reference to the accompanying drawing of which:-Fig.1 is a pictorial view of a front end of a vehicle having a bonnet according to the invention; Fig.2 is an underside view of the bonnet shown in Fig.1 showing an inner bonnet panel attached to an outer bonnet panel of the bonnet and a lock striker assembly according to one aspect of the invention fastened to the inner bonnet panel; Fig.3 is a rear view of the bonnet shown in Figs. 1 and 2 in the direction of arrow A' on Fig.1; Fig.4 is an enlarged rear view of the lock striker assembly shown in Figs. 2 and 3; Fig.5 is an enlarged pictorial view of the lock striker assembly shown in Figs. 2 to 4; Fig.6a is a cross-section through a mechanical fastening means for use in fastening the lock striker assembly to the inner bonnet panel; and Fig.6b is a plan view of the mechanical joint shown in Fig.6a showing the section line x-x along which the view of Fig.6a is taken.

Referring now to Figs. 1 to 5 there is shown a motor vehicle 10 having a body structure 11 and a bonnet 20 having leading and trailing ends hingedly secured to the body structure 11 for pivotal movement about the trailing end of the bonnet 20 between closed and open positions. A forward direction of travel of the vehicle 10 is indicated by the arrow F' on Fig.1 and it will be appreciated that the terms leading' and trailing' are in relation to this direction of motion.

The bonnet 20 has an outer bonnet panel 21 which defines part of the outer surface of the motor vehicle 10 and an inner bonnet panel 22 fastened to the outer bonnet panel so as to reinforce it and provide a support for hinges (not shown) used to pivotal connect the bonnet 20 to the body structure 11.

The inner bonnet panel 22 is fastened to the outer bonnet panel 21 in this case by a clinch flange and adhesive bonding. It will however be appreciated that the inner bonnet panel could be fastened to the outer bonnet panel in some other way such as, for example, a plurality of spot welds spaced out on the perimeter of the inner body panel 22 or that a combination of these methods could be used.

Towards the leading end of the bonnet 20 a lock striker assembly 30 is fastened to the inner bonnet panel 22.

The lock striker assembly 30 comprise of two components namely a U-shaped lock striker 35 and a bridge used to fasten the lock striker 35 to the inner bonnet panel 22.

The bridge comprises of a central platform 33 joined at each end to an inclined support 32. Each of the inclined supports 32 is fastened to the inner bonnet panel 22 by a respective foot 31 so as to prevent relative movement between the respective foot 31 and the inner bonnet panel 22.

Each of the inclined supports 32 is arranged at an obtuse angle o' with respect to the platform 33 and at an acute angle a' with respect to the inner bonnet panel 22 so as to promote a controlled collapse of the bridge. That is to say, the bridge is relatively wide relative to its height so that it can more readily be collapsed.

The bridge and the inner bonnet panel 22 are both made in this case from steel and the feet 31 are fastened to the inner bonnet panel 22 by spot welding. The use of spot welding ensures that no part of the fastening means used to fasten each foot 31 to the inner bonnet panel 22 projects towards the outer bonnet panel 21. This arrangement of fastening is important because, in the event that the outer bonnet panel 21 is bent towards the inner bonnet panel 22 by say an impact of a body part against the outer body panel 21, there are no hard points associated with the fastening means that could increase the risk of injury to the body part.

The bridge extends transversely across the inner bonnet panel 22 that is to say it is arranged substantially normal to a longitudinal axis of the vehicle 10. This orientation allows for the bonnet 20 to rock about the lock striker 35 in a "see-saw" manner if the bonnet 20 is impacted against at a position offset from the lock striker 35.

The lock striker 35 is also in this case made from steel and is U-shaped having two legs joined by a common crossbar. The two legs are fastened to the platform 33 by arc welding or projection welding. The use of projection welding ensures that no part of the fastening means used to fasten the lock striker 35 to the platform 33 projects towards the outer bonnet panel 21. This arrangement of fastening is as before important because, in the event that the outer bonnet panel 21 is bent towards the inner bonnet panel 22 by say an impact of a body part against the outer body panel 21, there are no hard points associated with the fastening means that could increase the risk of injury to the body part.

The bridge is made from a single piece of pressed steel and the free edges of the platform 33 are bent over to form flanges 34a and the free edges of the two inclined supports 32 are bent over to form flanges 34b. The platform 33 and the two inclined supports 32 are of a "U" shape in transverse cross-section. However each of the flanges 34a, 35b need not be arranged at an exact right angle with respect to the component it is joined to.

The flanges 34a, 34b running along the free edges of the platform 33 and the two inclined supports 32 increase the resistance to bending of the platform 33 and the inclined supports 32 so as to provide a controllable collapse of the bridge when a force above a predetermined force is applied to the bonnet 20.

The value of this predetermined force is determined by various means including modelling and simulation testing and is the force where, if the bonnet 20 is impacted upon by a body part such as a head, it is desirable for the entire bonnet 20 to move with the body part so as to minimise injury. It will be appreciated that the lock striker 35 is unable to move away from the impact due to its engagement with a striker latch (not shown) mounted on part of the body structure 11 of the vehicle 10 such as for example a radiator support cross-rail. An example of a typical striker latch is shown in DE-U-20210249.

In the event of a force above the predetermined force being applied to the bonnet 20, the platform 33 will be bent into an arc shape thereby applying a bending moment to the two inclined supports 32 causing them also to bend.

Deformation of a structure due to bending can be accurately determined and is a reliable deformation mode. It is therefore possible to design the two inclined supports 32, the platform 33 and the flanges 34a, 34b, to cause the bridge to collapse in a very predictable and repeatable manner.

One advantage of using a bridge structure of the type shown is that, if the impact is applied offset to the lock striker 35, then the bonnet 20 is able to tilt or rotate about the lock striker 35 to absorb energy and the bridge is still able to collapse in a controlled manner by bending to accommodate the rotation.

A further advantage of the invention is that none of the fastening means used to fasten the bridge to the inner bonnet panel 22 project towards the outer bonnet panel 21.

This is important because during an impact with a pedestrian it is likely that the outer bonnet panel 21 will be deflected towards the inner bonnet panel 22 and so any hard objects directed towards the outer bonnet panel 21 will increase the risk of injury to the pedestrian.

Therefore although the invention has been described above with respect to the fastening of the bridge to the inner bonnet panel 22 by means of spot welding it will be appreciated that other fastening means that do not produce a projection in the direction of the outer bonnet panel 21 could also be used. For example, seam welding, brazing or adhesive bonding of the bridge to the inner bonnet panel could be used. As yet further alternatives, countersunk rivets or, as shown in Figs. 6a and 6b, some form of mechanical joint could be used. In all these cases the fastening means does not project towards the outer bonnet panel 21.

In Figs. 6a and 6b the fastening means comprises of two tabs 23 formed from the inner bonnet panel 22 which are engaged in an aperture 36 in a respective foot 31 and bent over to fasten the respective foot 31 to the inner bonnet panel 22. Note that no part of the fastening projects towards the outer bonnet panel 21.

Although the bridge has been described above with respect to the preferred embodiment as being made from steel it will be appreciated that it could be made from other materials such as, for example and without limitation, plastics or aluminium alloy.

-10 -Furthermore, although the invention has been described above in relation to an embodiment in which the bonnet is hinged near to its trailing end to part of the structure of the motor vehicle and the bridge is fastened near to the leading end of the inner bonnet panel, it will be appreciated that the invention could also be applied to a front hinged bonnet but in this case the bridge will be located near to the trailing end of the inner bonnet panel and the deformation of the bonnet will more likely be caused by a head of an adult impacting against the outer bonnet panel.

It will be appreciated by those skilled in the art that although the invention has been described by way of example with reference to one or more embodiments it is not limited to the disclosed embodiments and that one or more modifications to the disclosed embodiments or alternative embodiments could be constructed without departing from the scope of the invention as set out in the appended claims.

Claims

-11 -Claims 1. A bonnet for a vehicle having a leading end and a trailing end, the bonnet comprising an outer bonnet panel, an inner bonnet panel fastened to the outer bonnet panel and a lock striker fastened near to one of the leading and trailing ends of the inner bonnet panel for locking the bonnet in a closed position during normal use of the vehicle, the lock striker being fastened to the inner bonnet panel by a transversely extending bridge so that it is arranged in a spaced apart relationship with respect to the inner bonnet panel, wherein the bridge comprises a central platform joined at each end to an inclined support, each of the inclined supports being fastened to the inner bonnet panel by a respective foot so as to prevent relative movement between the respective foot and the inner bonnet panel and the bridge is arranged to collapse in a progressive manner when a force above a predetermined force is applied to it.
2. A bonnet as claimed in claim 1 wherein each of the inclined supports is arranged at an obtuse angle with respect to the platform and at an acute angle with respect to the inner bonnet panel so as to promote the controlled collapse of the bridge.
3. A bonnet as claimed in claim 1 or in claim 2 wherein the bridge is made from a single piece of material.
4. A bonnet as claimed in any of claims 1 to 3 wherein free edges of the platform have flanges running therealong to increase the resistance to bending of the platform.

-12 -
5. A bonnet as claimed in claim 4 wherein the bridge is made from pressed steel and the free edges of the platform are bent over to form the flanges.
6. A bonnet as claimed in any of claims 1 to 5 wherein free edges of the two inclined supports have flanges running therealong to increase the resistance to bending of the inclined supports
7. A bonnet as claimed in claim 6 wherein the bridge is made from pressed steel and the free edges of the two inclined supports are bent over to form the flanges.
8. A bonnet as claimed in any of claims 1 to 7 wherein no part of the fastening means used to fasten each foot to the inner bonnet panel projects towards the outer panel.
9. A bonnet as claimed in any of claims 1 to 8 wherein no part of the fastening means used to fasten the lock striker to the platform projects towards the outer bonnet panel.
10. A motor vehicle having a bonnet as claimed in any of claims 1 to 10.
11. A bonnet substantially as described herein with reference to the accompanying drawing.
12. A motor vehicle substantially as described herein with reference to the accompanying drawing.