GB2344790A

GB2344790A - Motor vehicle bonnet assembly

Info

Publication number: GB2344790A
Application number: GB9827904A
Authority: GB
Inventors: Gary James Skeggs
Original assignee: MG Rover Group Ltd
Current assignee: MG Rover Group Ltd
Priority date: 1998-12-18
Filing date: 1998-12-18
Publication date: 2000-06-21
Anticipated expiration: 2018-12-18
Also published as: GB2344790B; GB9827904D0

Abstract

A bonnet assembly for a motor vehicle has a bonnet (12) hinged about a generally horizontal, forwardly located axis, in which the bonnet (12) is supported, in a closed position, on an impact absorbing transverse beam (28), supported on laterally disposed wings (30, 32). The transverse beam (28) helps reduce the risk of injury to a pedestrian upon impact.

Description

Motor Vehlcle Bonnet Assembly The present invention relates to an improved motor vehicle bonnet assembly, and in particular to a motor vehicle bonnet assembly aspects of which lead to improved pedestrian impact performance.

Motor vehicle bonnet assemblies have in the past been designed to accommodate impacts between the motor vehicle bonnet and obstructions, such as trees, items of road furniture and other motor vehicles so as to prevent injury to the occupant or occupants of the motor vehicle.

It will be appreciated that such obstructions are relatively rigid or immovable and this has lead to relatively rigid designs for motor vehicle bonnet assemblies.

However, while such designs have served well to protect those within the motor vehicle, pedestrians and the like have not been so fortunate. In the event of a collision between a motor vehicle and a pedestrian it is usually the lower part of the pedestrian that is first impacted. In such cases, for an adult the impact is usually in the region of the knee causing a bending moment to be applied on the joint. As a result, either the pedestrians'legs are broken or the pedestrian is pushed to the floor and dragged beneath the still moving motor vehicle. Sometimes, both may result. In the case of a child the impact is typically in the upper body region and the child is usually thrown to the floor and dragged beneath the motor vehicle.

The bumper is not the only point of contact with a pedestrian on impact.

The front edge of a bonnet assembly of a motor vehicle is typically impacted either by, in the case of an adult in the region of the hips or in the case of a child by the head. This edge typically contains the bonnet latching mechanism and as such is more rigid than the remainder of the bonnet assembly. Indeed, the latching mechanism contains many sharp edges normally covered by the skin of the bonnet assembly.

In the case of an adult, the head is typically impacted by a rear region of the bonnet assembly. The head may impact on wiper blades and washer fluid jets which are typically located in this region. Further there is a risk that having avoided these dangers that the skin of the bonnet assembly is not sufficiently resilient to prevent impact between the head and the engine block beneath.

A number of steps have been taken to address these dangers. For example, it is known to provide a forwardly directed skirt below a bumper of a motor vehicle. This skirt impacts an adult pedestrian in the region of the ankle in order to try to tip the pedestrian onto the bonnet, a less dangerous area than beneath the vehicle. However, there is still a danger that the pedestrian's ankles become trapped by the skirt resulting in the pedestrian becoming doubled over and ensuring the pedestrian's head impact the forward edge of the bonnet assembly.

It is an advantage of the present invention that it addresses and provides a solution for at least some of the problems addressed above.

According to a first aspect of the invention a bonnet assembly for a motor vehicle comprises a bonnet hinged about a generally horizontal forwardly located axis, moveable between a raised open position and a lowered closed position, in which the bonnet is supported in the closed position on an impact absorbing transverse beam supported on laterally disposed wings.

This has the advantage that the transverse beam is able to provide pedestrian impact benefits to at least ameliorate the likeliheod of injury to a head of an adult pedestrian.

Preferably a latch mechanism is located at at least one side of the bonnet assembly.

There is a reduced likelihood of damage being caused to pedestrians impacting the leading edge of the bonnet since the latching mechanism is no longer located within the front edge of the bonnet assembly. Furthermore this space or area may be used actively to implement additional pedestrian impact measures.

Preferably the at least one bonnet latch is arranged to release the bonnet assembly in the event of a pedestrian impact.

Preferably the bonnet includes a bumper and a bonnet catch is located beneath the leading edge of the bonnet assembly in a region beneath the bumper.

The catch enables the bumper to bellow absorbing at least part of the impact'in a region corresponding to a lower leg region of an adult pedestrian and flex outwardly to push the lower leg region of an adult pedestrian away from the bumper. Due to the dynamics of the system, this should tip the adult pedestrian onto the bonnet of the motor vehicle where the risk of injury is less than that beneath the motor vehicle. In the case of a child pedestrian the bumper will also bellow to absorb at least part of the impact. In such a case the region of impact will correspond approximately to the hip region of the child. The bumper will then flex back to push the child away from the underside of the motor vehicle.

The invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 shows a schematic side view of a motor vehicle front end assembly according to the present invention prior to impact with an adult pedestrian ;- Figure 2 shows a schematic. side view of a motor vehicle front end assembly according to the present invention at a first stage of impact with an adult pedestrian; Figure 3 shows a schematic side-view of a motor vehicle front end assembly according to the present invention at a second stage of impact with an adult pedestrian; Figure 4 shows a schematic side view of a motor vehicle front end assembly according to the present invention at a third stage of impact with an adult pedestrian; Figure 5 shows in perspective a diagrammatic view of a motor vehicle front end showing different aspects of the present invention : Figure 6 shows in perspective a view of a motor vehicle front end showing a first aspect of the present invention; Figure 7 shows a diagrammatic view of a motor vehicle front end according to a second aspect of the present invention; Figure 8 shows in side section a latch mechanism forming a part of the present invention; Figure 9 shows in side section a catch mechanism forming a part of the present invention; and Figure 10 shows a perspective view of the catch mechanism of Figure 9.

Referring to Figures 1 to 4, there can be seen a motor vehicle front end assembly 2 incorporating various aspects of the present invention. A bumper 4 is located at the front of the front end assembly 2 so as to provide a first point of impact of the motor vehicle in the region of the lower legs 6 of an adult pedestrian (Figure 1). The bumper is provided with flanges extending above and below the bumper. The lower flange forms a skirt 8 beneath the bumper. The skirt 8 is secured to at least two points disposed laterally across the motor vehicle front end. The upper flange 10 extends up towards a leading edge of the motor vehicle front end assembly. The upper flange may conveniently include a radiator grille. In the embodiment of the present invention shown in Figures 1 to 4, the upper flange 10 extends into and forms part of the front bonnet 12.

An engine 14 is supported in the motor vehicle front end behind the bumper and beneath the front bonnet. A radiator 16 and a condenser 18 are conveniently located between the engine and the front bumper.

On impact, the bumper 4 flexes, bellowhl out into the areas above and below the bumper itself (Figure 2). The skirt 8 is secured by way of a catch mechanism 20, to be described later, that provides for some giving of the skirt to absorb some of the energy of impact. The upper flange also bellows outwards.. Further, since the knee of the adult pedestrian is now typically subject to a flat area upon impact instead of a curved area, a lower bending moment upon the knee is provided.

As the upper flange 10 bellows outwards, it allows a leading edge of the bonnet to come into contact with a hip area 22 of the adult pedestrian (Figure 3). In the present invention, there are no latching mechanisms located at the leading edge of the bonnet and so the risk of injury is reduced. Further, there is now a large enough clearance between the leading edge of the bonnet and the motor vehicle front end to enable the hip area to impact without a large amount of damage. The impact of the hip area, in the embodiment shown leads to further bellowing of the bonnet 12.

Latching mechanisms 26, described in greater detail below, are provided to the side of the vehicle bonnet between the bonnet and respective left and right wings of the motor vehicle. The latching mechanisms are such that on deformadon of the bonnet caused by pedestrian impact, the bonnet 12 will be released from the wings and will swing up to meet the pedestrian.

The pedestrian's head 24 then impacts the bonnet (Figure 4). The bonnet 12 acts as a cushion between the pedestrian's head 24 and the engine block 14 beneath the bonnet. The bellowing out of the bonnet, in addition to or instead of the freeing of the bonnet from the wings, creates a greater potential stroke between the pedestrian's head and the engine block, thereby providing greater scope for the pedestrian's head to be slowed down prior to impact with the engine block, thereby satisfying pedestrian impact criteria.

Finally, by the time the head 24 impacts the bonnet 12 the legs of the pedestrian have been thrown upwards. In the meantime, as the bonnet is forced back down, the bumper 12 is forced back out. This provides a further energy damping mechanism as the legs return groundward.

It will be understood that in the case of a child that the first two mechanisms, namely the bellowing of the bumper and the upper flange, will serve to lessen the damage caused by a pedestrian impact.

Accordingly, each of the aspects of the invention work together to provide an integrated system to accommodate pedestrian impacts with a minimum of damage to the pedestrian. The different aspects are shown diagramatically in Figure 5.

A--first aspect of the invention is provided beneath the bonnet 12 of the motor vehicle.

The bonnet is shown in ghost in Figure 6. The bonnet opens from the front of the motor vehicle and is moveable between a lowered closed position and a raised open position. This means that the bonnet once free of the latch mechanisms will pivot forwardly towards the pedestrian. In the embodiments of Figures 1 to 4 and 6 the bonnet extends beneath the bumper.

As the bonnet 12 returns to a lowered position, carrying the pedestrian, it is important that the inertia of the pedestrian is not used to dash the brains of the pedestrian against the engine 14. For this reason there is located at the end of the bonnet above the engine 14 a transverse impact absorbing structure 28 supported by a pair of laterally disposed wing supports 30,32. Preferably, the transverse impact absorbing structure 28 comprises a beam of foamed material. The beam is used to support a top edge of the bonnet to prevent the bonnetl2, and thus the pedestrian's head, impacting on the engine 14.

The catch mechanism 20 securing the skirt 8 in position will now be described in more detail. It will be understood that the catch mechanism 20 may extend across the motor vehicle front end or may comprise a series of catch mechanisms located across the motor vehicle front end.

In the illustrated embodiment of Figure 8, the skirt 8 of the bonnet is secured at one end to a mounting 34 by way of the catch mechanism 20. The end of the skirt 8 is provided with a profile portion 36 extending laterally across the skirt in the region of the catch mechanism.

A catch block 38 is secured to the skirt 8 between the edge of the skirt and the profile portion 36. The profile portion 36 and the catch block 38 are provided with complementary features to aid in the location of the catch block. A fixing plate 40 is provided on an outer surface of the skirt edge and is secured to the catch block by a rivet 42 or any other suitable means.

The catch block 38 is further provided on an upper surface 44 with a raised clip 46 and a pivot connection 48. The clip 46 retains a portion of a locking mechanism 50. An intermediate member 52 comprises a central web 54 from which extend first and second angularly disposed flanges 56,58. The central web is secured by a threaded fastener 60 or any other suitable means to the mounting point. The pivot connection 48 between the intermediate member 52 and the catch block is located at a free end of the first flange 56. A free end of the second flange 58 abuts, but is not connected to the upper surface 44 of the catch block.

In use, the locking mechanism 50 is actuated to release the portion of the locking mechanism to retained by the clip. Release of the locking mechanism 50 may be actuated from within a passenger cell of the motor vehicle in a known manner or by any other suitable means. The bonnet 12 may then rotate about the pivot connection 48 between the catch block 38 and the intermediate member 52 to the position shown in ghost in Figure 7 to expose an engine cavity of the motor vehicle.

In the event of an impact, the portion of the locking mechanism 50 retained by the clip will remain so retained. Thus, the bonnet is not free to rotate. However, since the free end of the second flange 58 is not connected to the catch block 38 as the skirt 8 bellows the end of the skirt can rotate slightly about the pivot connection 48 against the force of the locking mechanism to absorb impact energy. Next the skirt 8 is moved back from the bellowed condition both by the force of the locking mechanism and the inherent resilience of the skirt, and the second flange 58 acts as a brace to ensure that the bumper 4 is in the right place as the legs of the pedestrian fall downward.

Where the bonnet front end does not extend as a unitary formation beneath the bumper, the locking mechanism may be omitted from the catch mechanism.

The latch mechanisms 26 connecting the bonnet 12 to the motor vehicle wings will now be described in more detail. Each latch mechanism 26 is in two parts, a first member 60 which may be connected to the bonnet and a second member 62 which may be connected to the motor vehicle body. The connections may be made in any suitable manner.

The first member 60 comprises a plate 64 having a keyhole cut-out 66. The keyhole cut-out 66 is defined by oppositely disposed first and second limbs 68,70. The keyhole cutout comprises a substantially circular opening 72 connected to a narrowing lead-in portion 74 to define a restricted channel 76 between the first and second limbs.

The second member 62 comprises a frame 78 on which is mounted a sliding member 80.

The frame 78 comprises a central web 82 with a first upstanding flange 84 at a first end and a second upstanding flange 86 at a second-end.

The sliding member 80 comprises a first part 88 slidably mounted at a first end in the first flange. A second end of the first part 88 is provided with an oblique surface 90. The sliding member 80 further comprises a second partS2 slidably mounted in the second flange.

A lateral protrusion 94 connects a first end of the second part 92 with the second end of the first part 88. A second end of the second part 92 is provided with a plate member 96. The plate member 96 has a peripheral region between an inner face 98 of the plate member connected to the second end of the second part of the sliding member and an outer face 100 of the plate member. Spring means are provided between the second flange 86 and the inner face 98 of the plate member to urge the plate member 96 away from the second flange 86. A helical spring 102 is shown in the illustrated embodiment.

The plate member 96 may conveniently be received within an opening 104 provided in a neighbouring body panel 106 of the motor vehicle. The plate member 96 may conveniently be shaped and adapted to bear a badge or other insignia of a motor vehicle manufacturer.

In use, on closing of the bonnet 12 the first and second members 60,62 of the latch mechanism are brought together. In particular, the plate 64 abuts the oblique surface 90 of the first part 88 of the sliding member and pushes it into a retained or locked position in which the oblique surface 90 of the second end of the first portion is retained within the keyhole cut-out 64 in the plate 66. This pulls the sliding member 88 against the force of the spring means. In the case where the plate member 96 extends through an opening in the neighbouring body panel 106, such as in the illustrated embodiment, this draws the outer surface 100 of the plate member flush with an outer surface 108 of the neighbouring body panel 106. Release of the latch mechanism by movement of the keyhole plate may be actuated from within the passenger cell in a known manner or by any other suitable means.

In the case where the plate member extends through an opening in a neighbouring body panel, if the panel 64 has not moved the oblique surface 90 to the retained position a visible indication of this is provided in that the outer surface 100 of the plate member will stand proud of the outer surface 108 of the neighbouring body panel.

In the event of an impact, the bonnet will be deformed causing the plate 64 to splay outwardly. Once the deformation of the bonnet causes the plate 64 to be splayed past the angle of the oblique surface 90, this will have the effect of allowing the lateral protrusion 94 to pass through the channel in the keyhole cut-out 66 thereby to free the bonnet from the motor vehicle allowing the bonnet to rise to meet the oncoming pedestrian.

Claims

1. A bonnet assembly for a motor vehicle comprising a bonnet hinged about a generally horizontal forwardly located axis, moveable between a raised open position and a lowered closed position, in which the bonnet is supported in the closed position on an impact absorbing transverse beam supported on laterally disposed wings.

2. A bonnet assembly according to claim 1, characterised in that a latch mechanism is located at at least one side of the bonnet assembly.

3. A bonnet assembly according to claim 2, characterised in that the at least one bonnet latch is arranged to release the bonnet assembly in the event of a pedestrian impact.

4. A bonnet assembly substantially as described herein with reference to and as illustrated in Figures 5 and 6 of the accompanying drawings.

5. A bonnet assembly according to any previous claim, characterised in that it further comprises a latch mechanism having a first member and a second member, the first member comprising a plate having a cut-out defining first and second limbs, the second member comprising a slidable member having first and second parts joined by an intermediate portion, one end of the first part adjacent the intermediate portion having an oblique surface adapted in use to be displaced by the first member into a retained position.

6. A bonnet assembly according to claim 5, characterised in that the second member further comprises a frame in which the slidable member is mounted.

7. A bonnet assembly according to claim 6, characterised in that the second member further comprises a plate member mounted at an end of the second part of the slidable member outside of the frame.

8. A bonnet assembly according to claim 7, characterised in that the second member further comprises spring means disposed between an inner surface of the plate member and the frame.

9. A bonnet assembly according to claim 7 or claim 8, characterised in that the plate member is located in a n opening in a neighbouring body panel.

10. A bonnet assembly according to claim 9, characterised in that the outer surface of the plate member is flush with an outer surface of the neighbouring body panel when the oblique surface is in the retained position.

11. A bonnet assembly according to any of claims 5 to 10, characterised in that one of the first and second members is located on a vehicle body panel and the other of the first and second members is located on a vehicle body frame member.

12. A bonnet assembly according to claim 11, characterised in that the vehicle body panel comprises a bonnet panel or a fender panel.

13. A bonnet assembly according to any of claims 5 to 12, characterised in that the first member may be actuated to disengage the second member from within a passenger cell of a motor vehicle.

14. A bonnet assembly comprising a latch mechanism substantially as described herein with reference to and as illustrated in Figures 9 and 10 of the accompanying drawings.

15. A bonnet assembly according to any previous claim, characterised in that it further comprises a catch mechanism for providing a flexible connection between a portion of a resilient body panel and a mounting point of the motor vehicle, the catch having an intermediate member fixedly connected to the mounting point and connected to a catch block by way of a pivot, the catch block being fixedly connected to the body panel.

16. A bonnet assembly according to claim 15, characterised in that the catch block is formed as an integral part of the body panel.

17. A bonnet assembly according to claim 15 or claim 16, characterised in that the intermediate member comprises a web having a first flange portion and a second flange portion, the pivot being located at a free end of the second flange portion.

18. A bonnet assembly according to claim 17, characterised in that a free end of the first flange portion abuts the catch block.

19. A bonnet assembly according to any of claims 15 to 18, characterised in that a locking mechanism is provided between the intermediate member and the catch block to releasably retain the bonnet in position in relation to the mounting point.

20. A bonnet assembly according to claim 19, characterised in that the locking mechanism may be actuated from within the passenger cell of the motor vehicle.

21. A bonnet assembly comprising a catch mechanism substantially as described herein with reference to and as illustrated in Figures 7 and 8 of the accompanying drawings.

22. A bonnet assembly substantially as described herein with reference to and as illustrated in Figures 1 to 4 of the accompanying drawings.