GB2340453A - A motor vehicle wall assembly - Google Patents

Abstract

A wall assembly for a motor vehicle has an inner wall member 11 and an outer wall member 12 both of which are made from a plastics material and which are so contoured so as to provide a support for several components of the motor vehicle. In particular, a hollow beam section 10 is formed to support functional components such as an air bag cam. This section 101 acts on a cross-beam between "A" or front hinge posts of a motor vehicle and is formed by reciprocal deformations in the wall members 11, 12.

Description

2340453 A Motor Vehicle Wall Assembly This invention relates to a motor

vehicle wall assembly and in particular to such an assembly suitable to act as a firewall for a motor vehicle made from a plastics material.

It is well known to provide a firewall or bulkhead between the engine and passenger compartments of a motor vehicle. Such a firewall is normally made from steel or aluminium and is fastened to the structure of the vehicle by welding.

It is usual with such a prior art wall assembly to attach the dashboard assembly to the firewall after the firewall has been secured in place. This has the disadvantage that it requires the fitting of numerous components within a very confined space which is both a difficult and a costly exercise.

It is an object of this invention to provide an improved wall assembly for a motor vehicle.

According to the invention there is provided a motor vehicle wall assembly suitable to act as a fire wall, the assembly comprising two juxtaposed sheets of plastic material secured together to present a rigid wall to divide an engine compartment and a passenger compartment, the assembly being characterised in that between said sheets of plastic material a hollow beam section is constituted by a closed divergence between said sheets of plastic material and said hollow beam section is configured to act as a cross-beam for a vehicle in which the wall assembly is arranged upon which a functional component such as an airbag mechanism or steering 5 column can be resiliently secured.

Preferably, the beam section will be at the upper periphery of the assembly. The beam section may be box-shaped. Furthermore, the beam section may be filled to further reinforce it with foam, etc.

The wall assembly may include adjacent to the beam section, fastener 10 means to fasten functional components thereto.

The wall assembly may include apertures to allow passage of functional components therethrough. These apertures may be adjacent and/or through the beam section.

The assembly will be located between the so-called "A" posts or front 15 hinge pillars of a motor vehicle, The invention will now be described by way of example with reference to the accompanying drawing of which:Figurel is an exploded pictorial representation of a wall assembly according to the invention; Figure 2 is a cross-section on the line II-II on Figure 1; Figure 3 is a cross-section on the line III-III on Figure 1; Figure 4 is a cross-section on the line IV-IV on Figure 1; Figure 5 is an enlarged cross-sectional view of a combined temperature control and air distribution unit as shown in Figure 3; and Figure 6 is an end view of the combined temperature control and air distribution unit shown in Figure 5.

With reference to Figures 1 to 4 there is shown an inner plastic firewall 11, an outer plastic firewall 12 and a number of components of a motor vehicle in the form of a blower fan 13, an electronic control unit 14, an air conditioning evaporator 15, a heater unit 16 and a brake master cylinder unit 24 all of which are supported by the inner and outer firewalls 11, 12.

The firewall assembly formed by the inner and outer firewalls 11, 12 therefore provides a support for a number of components of the motor vehicle that can be attached to one or other of the inner and outer firewalls 11, 12 before the wall assembly is fitted into the motor vehicle to provide a separator between an engine compartment of the motor vehicle and a passenger compartment of the motor vehicle.

At least one and preferably both of the inner and outer firewalls 11,. 12 are made from an impact resistant and flame retardant polymer material such as that described in US Patent number 5,286,576.

The inner and outer firewalls 11, 12 when fitted and secured together define an internal cavity. A noise and vibration absorbing material 27 is bonded, sprayed or moulded to the outer firewall 12 during manufacture of the outer firewall 12.

The inner firewall 11 is contoured to define a housing 23 for the electronic control unit 14, a easing 19 for the blower unit 13, a easing 18 for an interior air temperature unit of the motor vehicle in the form of the evaporator 15 and the heater 16, a receptacle for a combined temperature control and air distribution unit 51 and an integral pedal box support 22.

The inner and outer firewalls 11, 12 when fastened together define a number of air supply ducts 34, 35, 36 that extend from the combined temperature control and distribution unit 51 to various outlets 32, 37, 38 in the interior of the passenger compartment of the motor vehicle.

A face vent duct 34 is formed by a first wall member 31 formed as part of the inner firewall 11 and a second wall member 33 formed as part of the outer firewall 12. The second wall member 33 also forms a side wall to a demist duct arranged to supply air to a number of demist outlets 38 which 5 are located in close proximity to a windscreen 10 of the motor vehicle. A footwell duct 36 is arranged to supply air to a number of floor outlets 37 and also to the housing 23 for the electronic control unit 14.

With particular reference to Fig.3 it can be seen that the contour of the inner firewall 11 is such as to form a easing 18 for an interior air temperature unit of the motor vehicle. The interior air temperature unit comprising of an evaporator unit 15 forming part of an air conditioning circuit and a heater unit 16 forming part of a heater circuit of the motor vehicle.

As is well known in the art the flow of air through the evaporator unit 15 will produce air of a lower temperature than that entering the evaporator unit and in the case of the heater unit 16 the air exiting the heater unit 16 will be at a higher temperature than that entering it.

The air from the air temperature unit enters a combined temperature control and air distribution unit 51 via two apertures 41 and 42 in the upper surface of the casing 18.

To control the flow of air from the air temperature unit into the combined temperature control and distribution unit 15 first and second temperature control valves 54, 55 are provided in the combined temperature control and distribution unit 51. The effect of the first and second temperature control valves is to blend cold air entering through the aperture 41 with warm air entering through the aperture 42.

The air after miXing then flows through the combined temperature control and distribution unit and is distributed via first and second distribution valves 52, 53. The first distribution valve is used to control and distribute the flow of air from the combined temperature control and distribution unit 51 into both the demist duct 35 and the footwell duct 36. The second distribution valve 53 is used to control the flow of air into the face vent duct 34.

With particular reference to Figs. 5 and 6 it can'be seen that the first temperature control valve 54 is in the form of a flap valve and the second temperature control valve is in the form of a further flap valve 55.

The two flap valves 54 and 55 are interconnected by means of a linkage comprising of two levers 57, 59 joined by an elongate rod 58. The lever 59 is connected to the flap valve 54 and has a gear form 61 on one end thereof for engagement with a servo motor (not shown). Movement of the lever 59 will produce a corresponding movement of the lever 57 and therefore rotation of the flap valve 55 is interlinked with the rotation of the flap valve 54.

As shown in Fig.5 the flap valves 54, 55 are in a position to provide maximum cooling so that the flap valve 55 closes off the aperture 42 and the flap valve 54 opens aperture 41. Rotation of the flap valve 54 in a counter clockwise direction for approximately 800 will cause it to close off the aperture 41 but will result in the flap valve 55 opening the aperture 42. In this position maximum heating is provided.

Between these two positions the flow of air through apertures 41 and 42 will be regulated by the flap valves 54 and 55 and the flow through the aperture 42 will pass through a straightening baffle 56 before mixing with the cold air entering through aperture 41.

The mixed air then flows into the distribution part of the combined temperature control and distribution unit 51 in a mixed state. The distribution part of the combined temperature control and distribution unit 51 comprises of the first and second distribution valves 52 and 53. The first distribution valve is in the form of a quadrant valve which is rotatable through 120o from a first position in which it prevents the egress of air through an aperture 43 into the footwell duct 36 to a second position in which it prevents the flow of air through an aperture 44 into the demist duct 35 and in between these positions allows the air to flow to both.

The second distribution valve in the form of a flap valve 53 controls the flow of air through an aperture 45 into the face vent duct 34. The second distribution valve is rotatable through 600 from a position where it closes off the aperture 45 to a position where it provides a minimal restriction to flow through the aperture 45. The first and second distribution valves 52 and 53 are interconnected by means of a gear system comprising of a first distribution valve gear wheel 62 a second distribution valve gear wheel 64 and an idler gear 63. The idler gear 63 is driven by means of a servo means (not shown) to provide rotation of the first and second distribution valves 52 and 53.

The combined temperature control and distribution unit 51 is a selfcontained unit and is sealed to the inner firewall 11 by means of a number of seals 60 and is held in place by a couple of threaded fasteners (not shown).

With particular reference to Fig.4 there is shown a combined brake master cvIinder and servo 24 attached to the outer firewall 12. Th(2 ma-ter cylinder and servo 24 is operable by means of a push rod 65 connected to a brake pedal 67. The brake pedal 67 being pivotally connected to the pedal box support 22 by means of a pivot pin 66.

The inner and outer firewalls 11, 12 are joined together at a number of points by adhesive bonding and then the entire firewall assembly is fastened to structural members of the motor vehicle in the form of upper and lower box sections 25 and 26 by means of bolts 20.

The above two-part firewall construction, as a motor vehicle wall assembly, is described in United Kingdom patent application number 9719963.2 filed on 20 September 1997. However, more recently it has become known to provide a cross-beam between the so-called 'W' posts or front hinge posts of a motor vehicle upon which such functional components such as the air bag can be mounted. Typically, this cross-beam is an independent tube, usually formed from metal, securely fixed between the vehicle posts and sometimes supported with a reinforcing member between the cross-beam and the vehicle floor at an intermediate position.

Clearly, inclusion of an independent or separate cross-beam can add significantly to costs both in terms of components and assembly. Thus, in accordance with the present invention the wall assembly includes a hollow beam section 101 between the inner and outer fire walls 11, 12. This beam 10- section 101 provides a rigid cross-beam upon which functional components, ie. air bag can be mounted.

In the drawings, the beam section is constituted by a closed divergence between the fire walls 11, 12. Thus, when the walls 11, 12 are pressed or moulded, reciprocal deformations are provided in each wall 11, 12 such that upon assembly the beam section 101 is formed. It will be appreciated in order to achieve rigidity that bonding between the walls 11, 12 particularlyabout the deform ations/be am section 101 must be strong. In such circumstances ' it may be necessary to use fusion bonding between the walls 11, 12 or an appropriately strong adhesive. Thus strong bonding must be achieved at abutment areas 102, 103.

Fixing the wall assembly into a vehicle is achieved through fixing elements 104, 105 at either end of the beam section 101. These elements 104, 105 will secure the wall assembly to the so-called 'W' or front hinge posts of the vehicle.

As indicated above, the objective of the beam section 101 is to allow functional components to be fastened to it. Thus, the beam section 101 includes fastening mounts 106, 107 for such functional components as an air bag can or steering column mechanism. It will be understood that provision of the beam section 101 avoids the necessity for separate bracketing for these functional components and so there will be a reduction in component costs along with assembly complexity.

Normally, the beam section 101 will be square in order to provide appropriate rigidity. However, as the beam section 101 is essentially made from two sheets of plastics material, it may be necessary to augment structural strength by filling the beam with structural foam, etc. Furthermore, the beam section 101 could be ribbed to augment simple box structure strength.

It will be appreciated that in order to accommodate some function components it is necessary for those components to pass through the wall assembly. Thus, apertures may be provided, either adjacent or, provided there is not a too detrimental effect upon strength, through the beam section 101. These apertures will allow passage of the functional component through the wall assembly.

Within the wall assembly, the beam section 101 will be provided at the most convenient position to provide a mounting beam for functional components. Thus, as depicted in the drawings, the beam section 101 may be arranged at an upper periphery of the wall assembly.

Finally, the beam section 101 formed by reciprocal deformations in the walls 11, 12, may be bowed and include expansive or contractive features across its width in order to facilitate strength. Furthermore, rather than being a simple straight beam as depicted in the drawings, the beams section could undulate across the width of a vehicle with a zig-zag or castellated configuration in order to facilitate strength and subject to accommodation with other features of the wall assembly.

Claims (11)

1. A motor vehicle wall assembly suitable to act as a fire wall, the assembly comprising two juxtaposed sheets of plastics material secured together to present a rigid wall to divide an engine compartment and a passenger compartment, the assembly being characterised in that between said sheets of plastics material a hollow beam section is constituted by a closed divergence between said sheets of plastics material and said hollow beam section is configured to act as a crossbeam for a vehicle in which the wall assembly is arranged.upon which a functional component such as an air bag mechanism or steering column can be resiliently secured.

2. A wall mounting as claimed in Claim 1, wherein the beam section is arranged at an upper periphery of the assembly.

3. A wall assembly as claimed in Claim 1 or 2, wherein the beam section has a box-shaped configuration to facilitate rigidity and strength.

4. A wall assembly as claimed in Claim 1, 2 or 3, wherein the beam section is filled with structural foam to facilitate rigidity and strength.

5. A wall assembly as claimed in any preceding claim, wherein fastener means is located adjacent the beam section in order to secure functional components thereto.

6. A wall assembly as claimed in any preceding claim, wherein the assembly includes an aperture to allow passage of a functional component therethrough.

7. A wall assembly as claimed in Claim 6, wherein the aperture is adjacent to the beam section.

8. A wall assembly as claimed in Claim 6, wherein the aperture is through the beam section.

9. A wall assembly as claimed in any preceding claim, wherein fixing elements (104, 105) are provided to fix the assembly to 'W' or front hinge posts of a motor vehicle.

10. A wall assembly substantially as hereinbefore described with reference to the accompanying drawings.

11. A motor vehicle including a wall assembly is claimed in any preceding claim.