GB2339174A

GB2339174A - Bolster panel

Info

Publication number: GB2339174A
Application number: GB9913401A
Authority: GB
Inventors: Michael Mellor
Original assignee: MG Rover Group Ltd
Current assignee: MG Rover Group Ltd
Priority date: 1998-06-17
Filing date: 1999-06-09
Publication date: 2000-01-19
Also published as: GB9913401D0; GB9812944D0

Description

2339174 A BOLSTER PANEL The present invention relates to a bolster panel

and more particularly to a bolster panel for use within a motor vehicle for consistency within existing collision energy absorption mechanisms to protect a front seat occupant of that vehicle.

Motor vehicle safety is a paramount consideration within modem vehicles and in particular vehicle occupant protection during violent vehicle-to-vehicle crash scenarios is an important design objective. Clearly, various energy absorption mechanisms can be incorporated within a vehicle in order to appropriately dissipate collision impact energy. However, coupling an ostensibly soft and flexible vehicle occupant to those energy absorption mechanisms can create problems.

Within a motor vehicle, a particular difficulty is associated with the impact between a front seat occupant in the lower leg/knee area with the bolster panelling generally beneath that vehicle's dashboard. It will be understood that the dashboard incorporates a wide range of controls and instrumentation along with, in more recent years, air bags and a storage compartment such as a glove box. In such circumstances the design choices available may be 15 limited or constrained within a particular vehicle packaging scenario.

It will be understood that variation in bolster panel deformation response, panel rigidity and a tuned differential response across the lateral dimension of the vehicle would enable a vehicle designer to achieve bespoke collision/crash conditions. Unfortunately, most bolster panels are integrally formed and arranged to achieve a consistent response. Furthermore, it 20 will be understood that there is an aesthetic consideration to bolster panel design.

It will also be understood that, despite relatively sophisticated modelling, a great degree of actual bolster panel specification to achieve acceptable results must be achieved through empirical testing. With bespoke moulding of a test bolster panel, it will be understood by those skilled in the art that, the degree of adaptability to tune the bolster panel as a result of actual collision results is limited within the basic bolster panel mould design originally specified.

It is an object of the present invention to provide a bolster panel configured to achieve or allow greater rigidity and/or deformation response variation in comparison with previous 5 panels.

In accordance with the present invention there is provided a bolster panel for a vehicle, the panel comprising a hollow beam member selectively filled with structural foam to present a desired deformation response to an impact force applied to one side of the beam member.

Normally, the beam member will be a moulding and may typically be of a format similar to a motor vehicle glove box or a driver's lid. Furthermore, the beam member will generally include distinct compartments which may extend laterally and/or longitudinally through the beam member.

Respective compartments may include differential structural foam types or have foams of different mechanical properties in order to allow determination through appropriate choice of desired deformation response regionally through the bolster panel. Such variation in foam type or mechanical properties can also occur within one compartment or alternatively the whole hollow cavity of the beam member when so constructed.

Further in accordance with the present invention there is provided a method of providing a bolster panel comprising:

a) forming a hollow beam member with a hollow compartment therein; and b) selectively filling said hollow compartment with at least one structural foam to achieve a desired distribution of foam such that the compartment is filled with foam to achieve a desired deformation response for the bolster panel.

The method may achieve formation of the hollow beam through moulding, extruding or other assembly technique.

Filling of the hollow compartment can be achieved through drilling at least one hole in the compartment and injection of foam until bleed overflow. Typically, two holes will be drilled into the compartment with foam injection through a first hole and bleed overflow through a second hole.

An embodiment of the present invention will now be described by way of example only with reference to the accompany drawings, in which:

Figure I is a schematic perspective rear view of a bolster panel; and Figute 2 is a cross-section of a bolster panel in accordance with the present invention incorporated within a motor vehicle front facia.

In Figure 1, a typical glove box lid I is illustrated in rear perspective. The glove box lid I has a conventional configuration including a slightly curved and hollow beam 2 to which hinges 3, latch arms 4, handle rim 5 and a lock mounting 6 are secured. The glove box lid 1 is typically moulded from a plastics material and includes hollow recesses and compartments in order to provide mechanical strength, reduced material usage/weight and an aesthetic appeal to the beam 2 facia presented inwards of the vehicle.

The essential function of a glove box lid 1 is to act as a closure for a storage compartment in the motor vehicle dashboard facia. Thus, rigidity strength under collision impact is not a fundamental consideration. Previously, the beam 2 will typically be hollow as indicated previously in order to achieve lower material usage and weight which both contribute to manufacturing cost and convenience of usage.

In accordance with the present invention, the rear surface, ie. away from the aesthetic facia of the hollow beam 2 has holes 7, 8 drilled into it in order to gain access to the hollow compartments beneath. Typically, two holes 7, 8 will be drilled in order to allow foam to be inserted through one hole 8 until there is an overflow bleed through a second witness hole 7. Thus, the extent of foam filling into the beam 2 compartment is readily determinable and the second witness hole 7 allows air evacuation from the respective compartment of the beam 2.

Typically, the foam will be injected into the beam compartment or cavity. However, it will be appreciated that the foam could be poured into the cavity as an alternative. Foam injection is preferred in order to ensure good distribution of the foam within the beam 2 compartment. It will be appreciated that simple low pressure pouring of the foam may require manipulation of the panel in order to distribute the foam therein.

The foam used in accordance with the present invention is of a structural type.

Examples of such foams would be urethane or epoxy based foams, eg. TEROCURE (RTM). Thus, the foam has significant mechanical properties when set which enhance the capabilities of the beam 2. In such circumstances the beam 2, and therefore the bolster panel 1 created, can have significant rigidity in order to resist deformation during impact collision with an occupant. Under collision, the panel I would directly couple that occupant's impact energy to energy absorption mechanisms, ie. crush cans, etc, within a motor vehicle.

Alternatively, the panel 1 could be configured through the judicious and selective insertion of structural foam into the beam 2 compartment in order to achieve a desired deformation response. Thus, the beam 2 and therefore panel I would deform as intended in order to couple the occupant's collision energy to the vehicle's energy absorption mechanisms. For example, the beam 2 could be arranged to slightly bow during impact collision such that energy absorption mechanisms, ie. crush cans, could be configured at a slight incline relative to the panel I with the result that after bend deformation the panel 1 is substantially parallel with these crush cans during collision. Inclination of the crush cans may relieve some vehicle packaging problems in that the longitudinal length necessary to accommodate a suitable crush can may be reduced.

In Figure 2, a bolster panel 21 in accordance with the present invention is depicted in cross-section and relative to other facia components within a motor vehicle. The panel 21, comprising mouldings 22, 23 in combination, constitutes several cavities or compartments 24, 25, 26, 27 in which respective foam volumes 28, 29, 30, 31 are accommodated. These foam volumes 28, 29, 30, 31 are of a structural nature and so have significant and reliable mechanical properties in order to augment the existing perfonnance of the panel 21.

Furthermore, each foam volume 28, 29, 30, 31 may be different from each other in order to provide differential deformation response for the panel 21. The panel 21 may be divided into compartments longitudinally as illustrated or vertically in order to provide discrete compartments in which differential structural foam types, all having different mechanical properties, may be accommodated in order to tune the deformation response of the panel 21 under impact collision.

As indicated above, foam volumes 28, 29, 30, 31 are normally inserted by injection through respective holes 32 into compartments 24, 25, 26, 27. Thus, each compartment 24, 25, 26, 27 will typically include two holes, one for foam injection and the other for witness or bleed overflow to indicate that a particular compartment 24, 25, 26, 27 has been filled with foam.

It will be understood that certain compartments could be left hollow and without foam in order to further adapt or tune deformation response of the panel 21 under collision impact load.

The holes 32 will normally be sealed with a sealing compound or otherwise covered to prevent environmental ingress of dirt or moisture which may eventually damage the panel 21 or at least diminish that panel 21 aesthetically over time.

It will be appreciated by those skilled in the art, through provision of several injection holes 32 within each compartment 24, 25, 26, 27, that different foam types or foams of different mechanical properties could be incorporated within the same compartment 24, 25, 26, 27 in order to achieve further collision deformation response tuning for the panel 21.

A main advantage with regard to the current bolster panel 21 is that a generic hollow beam formed by mouldings 22, 23 may be designed and then, through iterative testing, specific rigidity and deformation response for the panel 21 achieved. Thus, the hollow beam is adapted through altering the structural foam inserted into the cavities 24, 25, 26, 27. By such means and the iterative empirical testing process, an appropriate bolster panel 21 can be achieved for a specific motor vehicle for response to identified impact collision criteria. Thus, and subsequently, the original hollow beam design may be adapted to reduce or eliminate or alter the foam inserts into the beam in view of the information received. This adaptation may be as a result of requirements for rigidity in terms of inserted structural foam types and specific mechanical properties for desired response.

As can be seen in Figure 2, the bolster panel 21 is typically secured within the front facia interior of a motor vehicle. Thus, an impact force in the direction of arrow heads F is presented to the bolster panel 21 typically through an occupant's lower leg/knee area during an impact collision. The bolster panel 21 is secured between a lower mounting 33 and an upper mounting 34 which in turn are secured to energy absorption mechanisms such as crush cans 35, 36 therebehind. Furthermore, above the bolster panel 21 there will typically be an air bag housing 37 in a modem motor vehicle. Thus, the bolster panel 21 when subjected to the impact force F will have a deformation response determined by a combination of the mechanical/structural parameters of the mouldings 22, 23 and the foam volumes 28, 29, 30, 31. In such circumstances, and by judicious design, the impact force F can be transferred through mountings 33, 34 to crush can mechanisms 35, 36 therebehind in order to most appropriately diminish the impact force F and so reduce injury to an occupant.

It will be appreciated that the present invention also allows more bespoke bolster panel types to be made for different motor vehicles rather than a compromise determined over a particular motor vehicle model range. Thus, for example, more rigid bolster panels may be provided in high performance vehicles, whilst lighter bolster panels may be included in other models of a particular vehicle range. In such circumstances, a single bolster panel moulding could be used with appropriate deformation tuning with structural foam in accordance with the present invention between different models within a vehicle range. Previously, to achieve such a bespoke bolster panel for each different model within a vehicle range would require different mould tooling with the inherent additional cost associated therewith.

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Claims

-8CLAIMS

1. A bolster panel for a vehicle, the panel including a hollow beam member selectively filled with structural foam to present a desired deformation response to an impact force applied to one side of the beam member.

2. A bolster panel as claimed in Claim 1, wherein the beam member is formed from a moulding assembly appropriately secured together to provide the hollow beam member.

3. A bolster panel as claimed in Claim I or Claim 2, wherein the hollow beam includes at least one distinct or discrete compartment which may be selectively filled with the structural foam.

4. A bolster panel as claimed in Claim 3, wherein each distinct compartment extends laterally and/or vertically within the beam member.

5. A bolster panel as claimed in Claim 3 and any claim dependent thereon, wherein respective distinct compartments include different structural foam types or a foam having different mechanical properties in order to determine the desired deformation response for the bolster panel in use.

6. A bolster panel as claimed in Claim 5, wherein the foam type or mechanical property of the foam incorporated within each respective compartment may vary across that compartment.

7. A bolster panel as hereiribefore described with reference to the accompany drawings.

8. A method of providing a bolster panel comprising:

9. A method as claimed in Claim 8, wherein the hollow beam is formed by moulding or extruding respective mould elements which are then secured together to form the hollow beam member therebetween.

10. A method as claimed in Claim 8 or Claim 9, wherein the hollow beam is selectively filled with foam by at least one hole drilled in the compartment and the foam injected until bleed overflow to ensure adequate distribution of foam within that compartment.

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11. A method as claimed in Claim 10, wherein two holes are drilled within the compartment, one hole being used to fill that compartment with foam whilst the other allows evacuation of air and facilitates foam bleed overflow to indicate that the compartment has the desired distribution of foam therein.

12. A method of providing a bolster panel substantially as hereinbefore described with reference to the accompanying drawings.

13. A motor vehicle including a bolster panel as claimed in any preceding claim.