Bulkhead

Abstract

A rear bulkhead 102 for a survival cell of a motor vehicle defines a main wall 106 configured to separate a passenger compartment from a rear cargo compartment and comprises at least one inclined skir

Description

TECHNICAL FIELD The present disclosure relates to a bulkhead. Aspects of the invention relate to a rear bulkhead for a survival cell of a motor vehicle, a vehicle comprising a rear bulkhead and a method of constructing a rear bulkhead for a survival cell of a vehicle. BACKGROUND It is known to provide some types of motor vehicle with a survival cell for protecting vehicle occupants in the event of an impact. Such survival cells typically include a rear bulkhead which separates a passenger compartment from a rear cargo compartment of a vehicle, in order to protect occupants within the passenger compartment from a hazard or impact rearward of the passenger compartment. For example, to provide occupant protection from a fuel tank or auxiliary fuel tank located behind the passenger compartment. Existing rear bulkheads can be difficult to install and can necessitate the use of supplementary tapes and seals to ensure a close fit against an internal wall of the vehicle body, It is an aim of the present invention to address one or more of the disadvantages associated with the prior art. SUMMARY OF THE INVENTION Aspects and embodiments of the invention provide a to a rear bulkhead for a survival cell of a motor vehicle, a vehicle comprising a rear bulkhead and a method of constructing a rear bulkhead for a survival cell of a vehicle as claimed in the appended claims. Throughout the summary of the invention, description and claims the terms front, rear, left, right, upper and lower are defined with reference to their normal use in the description of a forward facing upright standing vehicle. It follows that features of the invention are described in relation to a vehicle such that, for example, front features are those closer to the front of the vehicle than rear features and upper features are those closer to the top of the vehicle than lower features. According to an aspect of the present invention there is provided a rear bulkhead for a survival cell of a motor vehicle. The rear bulkhead defines a main wall configured to separate a passenger compartment from a rear cargo compartment and comprises at least one inclined skirt at a periphery of the rear bulkhead. The at least one inclined skirt extends at an inclination angle to the main wall and is configured to resiliently deform to increase the inclination angle when compressed between the main wall and an internal wall of the motor vehicle during installation of the rear bulkhead. It will be understood that the at least one inclined skirt can flex more easily relative to the main wall of the rear bulkhead than a skirt arranged parallel to the main wall. This flexing makes the rear bulkhead less sensitive to manufacturing variations and facilitates a closer fit between the periphery of the rear bulkhead and the interior of the vehicle body (e.g. a monocoque), whilst mitigating the need for cutting the periphery of the rear bulkhead to fit and / or sealing gaps between the periphery of the rear bulkhead and the vehicle body with supplementary tapes and / or sealant. In this way, the at least one inclined skirt allows the rear bulkhead of the survival cell to be installed more easily. The at least one inclined skirt may be a single inclined skirt provided along only a single edge of the rear bulkhead. For example, on only one side of the rear bulkhead. The compliance provided by a single skirt can allow the lateral position of the rear bulkhead to be adjusted to compensate for manufacturing tolerance variations. Optionally, the at least one inclined skirt comprises a first inclined side skirt on a first side of the rear bulkhead and a second inclined side skirt on a second side of the rear bulkhead. Such first and second inclined side skirts allow the rear bulkhead to form a close fit with both sides of a vehicle body. Optionally, the at least one skirt comprises an upper inclined skirt at an upper edge of the rear bulkhead. The upper inclined skirt may extend along part of the upper edge, or substantially the entire extent of the upper edge of the rear bulkhead. Such an upper inclined skirt allows the rear bulkhead to form a close fit with a roof of a vehicle body. Optionally, the at least one inclined skirt extends at an angle in the range of 20 to 70 degrees with respect to the main wall; optionally, in the range of 30 to 60 degrees; optionally, in the range of 40 to 50 degrees; optionally, substantially 45 degrees. Such a range of angles have been found to be particularly effective for allowing the inclined skirt to flex in order to form a close fit with the interior of a vehicle body. Optionally, the at least one inclined skirt comprises a plurality of facets arranged at an angle to each other. Having a plurality of facets arranged at an angle to each other, as well as at an angle relative to the main wall of the rear bulkhead, allows the at least one inclined skirt to track an interior surface of a vehicle body which is curved or multifaceted (e.g. as the interior of the vehicle body transitions between side and roof surfaces). Optionally, the rear bulkhead is formed of sheet metal; optionally, wherein the sheet metal comprises a thickness in the range of 1 mm to 2mm, preferably 1,25mm to 1.75mm, preferably substantially 1,5mm. Sheet metal provides a simple means of manufacturing the rear bulkhead since the sheet metal can easily be cut, stamped, bent, etc. to form the appropriate shapes. Such a thickness of sheet metal has been found to provide adequate protection for the survival cell of a motor vehicle, without adding too much weight to the motor vehicle. This is particularly advantageous for high performance motor vehicles (e.g. racing vehicles). Optionally, the rear bulkhead is formed of aluminium; optionally, powder-coated aluminium. Aluminium has a good strength to weight ratio which allows the rear bulkhead to provide sufficient protection for the survival cell of a vehicle whilst adding less weight than other materials, such as steel. This is particularly advantageous for high performance vehicles (e.g. racing vehicles). Powder-coating the aluminium allows the performance of the rear bulkhead to be improved, e.g. to increase durability of the aluminium, provide a fire-proof coating, etc. Optionally, the at least one inclined skirt is unitary with at least part of the main wall. For example, defined by a deformed or bent portion of the periphery of the main wall. Bending a piece of metal provides a simple means of forming the at least one inclined skirt. Optionally, the rear bulkhead comprises a plurality of discrete panels which are joined together to form the rear bulkhead. Having a plurality of discrete panels which are joined together to form the rear bulkhead (e.g. as opposed to a rear bulkhead formed as a single piece) allows the rear bulkhead to be inserted through openings in a vehicle body more easily, and to be assembled around vehicle components such as roll cage bars which pass longitudinally through the region occupied by the rear bulkhead. Furthermore, prior to assembly within a motor vehicle, the plurality of discrete panels can be stacked and / or palletised for easier storage and distribution in comparison to a rear bulkhead formed as a single piece. In some embodiments, the discrete panels are joined together by overlapping and fastening by blind rivets, bolts or other suitable fasteners. Optionally, at least some of the plurality of discrete panels have a plurality of cut-outs at their periphery which define apertures in the assembled rear bulkhead for receiving roll cage bars therethrough. Such apertures allow the rear bulkhead to be located inside a vehicle within the footprint of roll cage. For example, a passenger region of the roll cage between A-pillars and B-pillars may be located in front of the rear bulkhead and a rear brace structure of the roll cage may be located behind the rear bulkhead. The at least one inclined skirt may be formed by a single unitary component. Optionally, the at least one inclined skirt comprises a plurality of discrete skirt panels. Having a plurality of discrete planar skirt panels can provide easier flexing than skirts made of a single component. The plurality of discrete skirt panels may be unitary with the main wall. The plurality of discrete skirt panels may each comprise a connection region, by which the discrete skirt panel is fixed to the main wall, and a skirt region which extends at an inclination angle to the main wall. The skirt region may comprise multiple facets. Alternatively, the skirt region may be planar. Optionally, the plurality of discrete panels comprises a first side panel which extends from a central region of the bulkhead towards a first side of the bulkhead and a second side panel which extends from the central region to a second side of the bulkhead, wherein the first and second side panels define over 50% of the area of the main wall, and wherein a first inclined side skirt panel is connected to the first side panel at the first side of the rear bulkhead and / or a second inclined side skirt panel is connected to the second side panel at the second side of the rear bulkhead and / or an upper inclined skirt panel is connected to the first and / or second side panels at an upper edge of the rear bulkhead. Such a combination of rear bulkhead panels can easily be passed through door openings of a vehicle body to form the rear bulkhead in situ, whilst providing a close fit with the vehicle body at the periphery of the rear bulkhead. Optionally, the at least one inclined skirt comprises a nonlinear periphery for fitting around structures and / or components of a vehicle body. Having a nonlinear periphery allows the at least one inclined skirt to fit more closely around structures and / or components of a vehicle body which makes it easier to provide a seal between the rear bulkhead and the vehicle body for forming a sealed survival cell in front of the rear bulkhead. Optionally, the rear bulkhead further comprises a base structure having a plurality of panels which extend backwards at an angle from the main wall of the bulkhead to a lower edge of the bulkhead to reinforce a central region of the rear bulkhead; optionally, wherein the base structure comprises one or more slots, cut-outs and / or apertures for accommodating wiring and / or fixing brackets. Such a base structure provides the rear bulkhead with increased support, in comparison to a rear bulkhead with a planar base section. In addition, the panels of the base structure extending backwards provides a space in front of the base structure for increased storage and / or locating additional components within the survival cell in front of the rear bulkhead. Having one or more slots, cut-outs and / or apertures for accommodating wiring and / or fixing brackets allows the rear bulkhead to be appropriately mounted within a vehicle body without interfering with other components (e.g. electrical wiring) located proximal to a base of the vehicle body. According to another aspect of the present invention there is provided a vehicle comprising a rear bulkhead as disclosed herein. Such a vehicle benefits from the advantages of the rear bulkhead outlined above. According to anotheraspect of the present invention there is provided a method of constructing a rear bulkhead for a survival cell of a vehicle, the method comprising: (a) providing a vehicle body having one or more openings; (b) locating the rear bulkhead of the first aspect inside the vehicle body by inserting the rear bulkhead through the one or more openings; and (c) installing the rear bulkhead in position by flexing the at least one inclined skirt against an internal wall of the vehicle body. It will be understood that the at least one inclined skirt can flex more easily relative to the main wall of the rear bulkhead than a skirt arranged parallel to the main wall. This easier flexing of the at least one inclined skirt against an interior surface of the vehicle body makes the rear bulkhead less sensitive to manufacturing variations and facilitates a closer fit between the periphery of rear the rear bulkhead a vehicle body, whilst mitigating the need for cutting the periphery of the rear bulkhead to fit and / or sealing gaps between the periphery of the rear bulkhead and the vehicle body. In this way, flexing the inclined skirt allows a sealed survival cell to be provided more easily. Within the scope of this application it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and / or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and / or features of any embodiment can be combined in any way and / or combination, unless such features are incompatible. The applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to amend any originally filed claim to depend from and / or incorporate any feature of any other claim although not originally claimed in that manner. BRIEF DESCRIPTION OF THE DRAWINGS One or more embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 shows a rear perspective view of part of a vehicle interior including a roll cage, an auxiliary fuel tank and a rear bulkhead according to an embodiment; Figure 2 shows a rear perspective view of the rear bulkhead of Figure 1; Figure 3 shows a rearview of the bulkhead of Figures 1 and 2; Figure 4 shows a top view of a side portion of the bulkhead of Figures 1 to 3; Figures 5A and 5B show top and side views of the bulkhead of Figures 1 to 4; Figure 6 shows an enlarged view of an upper corner of the bulkhead of Figures 1 to 5; Figure 7 shows an enlarged view of a side skirt of the bulkhead of Figures 1 to 6; Figure 8 shows a vehicle in accordance with an embodiment of the invention; and Figure 9 shows a block, diagram of a method of constructing a rear bulkhead. DETAILED DESCRIPTION A rear bulkhead in accordance with an embodiment of the present invention is described herein with reference to the accompanying Figures 1 to 7. As shown in Figure 8, the rear bulkhead is installed in a vehicle 200. With reference to Figures 1 to 7, there is illustrated a rear bulkhead 102 for a survival cell of a motor vehicle. The rear bulkhead 102 defines a main wall 106 configured to separate a passenger compartment 108 from a rear cargo compartment 110. The rear bulkhead 102 also includes at least one inclined skirt 112A, 112B at a periphery 114 of the rear bulkhead 102. The at least one inclined skirt 112A, 112B extends at an inclination angle 0 to the main wall 106 (see Figure 4) and is configured to resiliently deform to increase the inclination angle 0 when compressed between the main wall 106 and an internal wall of the motor vehicle during installation of the rear bulkhead 102. It will be understood that the at least one inclined skirt 112A, 112B can flex more easily relative to the main wall 106 of the rear bulkhead 102 than the main wall 106 itself, or indeed a skirt arranged parallel to the main wall 106. This flexing makes the rear bulkhead 102 less sensitive to manufacturing variations and can facilitate a closer fit between the periphery 114 of the rear bulkhead 102 and a vehicle body (e.g. a monocoque), whilst mitigating the need for in situ modifications, such as cutting the periphery 114, of the rear bulkhead 102 to fit and / or sealing gaps between the periphery 114 of the rear bulkhead 102 and the vehicle body. In this way, the at least one inclined skirt 112A, 112B can allow a survival cell to be provided more easily. In the illustrated embodiment, the at least one inclined skirt includes a first inclined side skirt 112A on a first side 114A of the rear bulkhead 102 and a second inclined side skirt 112B on a second side 114B of the rear bulkhead 102. Such first and second inclined side skirts 112A, 112B allow the rear bulkhead 102 to form a close fit with sides of a vehicle body 202. In the illustrated embodiment, the first and second inclined side skirts 112A, 112B each have an optional nonlinear periphery 130A, 130B for fitting around structures and / or components of the vehicle body 202 in which the bulkhead 102 is fitted. In particular, the nonlinear peripheries 130A, 130B of the first and second inclined side skirts 112A, 112B each have a lower region 132A, 132B and an upper region 134A, 134B, where the lower regions 132A, 132B are comparatively narrower than the upper regions 134A, 134B, as best illustrated in Figures 3, 6 and 7. The nonlinear peripheries 130A, 130B also include a gradual transition region 136A, 136B between the lower and upper regions 132A, 132B, 134A, 134B. It will be understood that the nonlinear peripheries 130A, 130B are useful for providing a close fit with an interior of a vehicle body which has a comparatively narrower width proximal to a base of the vehicle body and a comparatively wider width closer to a roof of the vehicle body. In the illustrated embodiment, the first inclined side skirt 112A has a lower facet 144A and an upper facet 145A which are arranged at an angle to each other. Similarly, the second inclined side skirt 112B has a lower facet 6 144B and an upper facet 145B which are arranged at an angle to each other. The lower and upper facets 144A, 144B, 145A, 145B being arranged at an angle to each other (as well as an angle to the main wall 106) allows the first and second inclined skirts 112A, 112B to track an interior surface of the vehicle body 202 which is curved or multifaceted (e.g. as the interior of the vehicle body 202 transitions between side and roof surfaces). In alternative embodiments, the first and second inclined skirts 112A, 112B may be planar (i.e. not multifaceted). The rear bulkhead 102 also includes an upper skirt 116 at an upper edge 118 of the rear bulkhead 102. The upper skirt 116 extends along substantially the entire extent of the upper edge 118 of the rear bulkhead 102. In the illustrated embodiment, the upper skirt 116 is not inclined relative to the main wall 106 (i.e. the upper skirt 116 is parallel to the main wall 106). However, in some embodiments, the upper skirt 116 extends at an inclination angle to the main wall 106 in a similar manner to the first and second inclined side skirts 112A, 112B to further facilitate installation of the rear bulkhead 102. In the illustrated embodiment, the upper skirt 116 has a nonlinear periphery 117 for fitting around a nonlinear structure of the vehicle body 202. In particular, as best illustrated in Figure 6, the nonlinear periphery 117 of the upper skirt 116 has a curved region 117A, a stepped region 117B and an undulating region 117C for fitting against corresponding curves, steps, and undulations in the vehicle body 202. This makes it easier to provide a close fit between the rear bulkhead 102 and the vehicle body 202 when forming the survival cell. In the illustrated embodiment, the rear bulkhead 102 has a plurality of discrete panels 120A, 120B, 124A, 124B, 128, 138 which are joined together to form the rear bulkhead 102. In the illustrated embodiment, the rear bulkhead 102 has a first side panel 120A which extends from a central region 122 of the rear bulkhead 102 towards the first side 114A of the rear bulkhead 102, and a second side panel 120B which extends from the central region 122 to the second side 114B of the rear bulkhead 102. The first and second side panels 120A, 120B are joined together in the central region 122. In particular, as illustrated in Figures 2 and 3, a joining strip 123 overlaps with inner edges of the first and second side panels 120A, 120B and the first and second side panels 120A, 120B are both joined to the joining strip 123 (and thus to each other) by fastening blind rivets, bolts or other suitable fasteners through the overlapping joining strip and inner edges of the first and second side panels 120A, 120B. In the illustrated embodiment, the first and second side panels 120A, 120B define over 50% of the area of the main wall 106. In alternative embodiments the first and second side panels 120A, 120B define less than 50% of the area of the main wall. In the illustrated embodiment, the rear bulkhead 102 also has a first inclined side skirt panel 124A which is connected to the first side panel 120A proximal to the first side 114A of the rear bulkhead 102. The first inclined side skirt panel 124A includes the first inclined side skirt 112A mentioned above, and a connection portion 126A which overlaps with an outer edge of the first side panel 120A. It will be understood that the connection portion 126A of the first inclined side skirt panel 124A may form a peripheral edge of the main wall 106. Put another way, the connection portion 126A defines a connection region of the first inclined side skirt panel 124A, by which the first inclined side skirt panel 124A is fixed to the main wall 106, and the first inclined side skirt 112A defines a skirt region of the first inclined side skirt panel 124A which extends at an inclination angle 0 to the main wall 106. In some embodiments, the first side skirt 112A is unitary with a periphery of the main wall 106. For example, in the illustrated embodiment, the first side skirt 112A is deformed or bent from the connection portion 126A of the first inclined side skirt panel 124. It will be understood that the first inclined side skirt panel 124A can be joined together with the first side panel 120A by fastening blind rivets, bolts or other suitable fasteners through the overlapping connection portion 126A of the first inclined side skirt panel 124A and the outer edge of the first side panel 120A. Alternatively, the first inclined side skirt panel 124A can be joined together with the first side panel 120A by adhering or welding the overlapping connection portion 126A and outer edge of the first side panel 120A. The rear bulkhead 102 also has a second inclined side skirt panel 124B which is connected to the second side panel 120B proximal to the second side 114B of the rear bulkhead 102. The second inclined side skirt panel 124B includes the second inclined side skirt 112B mentioned above, and a connection portion 126B which overlaps with an outer edge of the second side panel 120B. It will be understood that the connection portion 126B ofthe second inclined side skirt panel 124B may form a peripheral edge of the main wall 106. Put another way, the connection portion 126B defines a connection region ofthe second inclined side skirt panel 124B, by which the second inclined side skirt panel 124B is fixed to the main wall 106, and the second inclined side skirt 112B defines a skirt region ofthe second inclined side skirt panel 124B which extends at an inclination angle 0 to the main wall 106. In some embodiments, the second side skirt 112B is unitary with a periphery ofthe main wall 106. For example, in the illustrated embodiment, the second side skirt 112B is deformed or bent from the connection portion 126B ofthe second inclined side skirt panel 124B. It will be understood that the second inclined side skirt panel 124B can be joined together with the second side panel 120B by fastening blind rivets, bolts or other suitable fasteners through the overlapping connection portion 126B ofthe second inclined side skirt panel 124B and the outer edge ofthe second side panel 120B. Alternatively, the second inclined side skirt panel 124B can be joined together with the second side panel 120B by adhering or welding the overlapping connection portion 126B and outer edge ofthe second side panel 120B. In the illustrated embodiment, the rear bulkhead 102 also has an upper skirt panel 128 connected to the first and second side panels 120A, 120B proximal to the upper edge 118 ofthe rear bulkhead 102. The upper skirt panel 128 is a planar panel including the upper skirt 116 mentioned above. The planar upper skirt panel 128 overlaps with an upper edge of the first and second side panels 120A, 120B. It will be understood that the planar upper skirt panel 128 forms a peripheral edge of the main wall 106 (i.e, an upper peripheral edge). It will be understood that the upper skirt panel 128 can be joined together with the first and second side panels 120A, 120B by fastening blind rivets, bolts or other suitable fasteners through the overlapping upper skirt panel 128 and the upper edges of the first and second side panels 120A, 120B. Alternatively, the upper skirt panel 128 can be joined together with the first and second side panels 120A, 120B by adhering or welding the overlapping portion of the upper skirt panel 128 and upper edges of the first and second side panels 120A, 120B. It will be understood that in embodiments where the upper skirt 116 is an inclined skirt, the upper skirt panel 128 may include a connection portion similar to the connection portions 126A, 126B of the side skirt panels 124A, 124B and an inclined upper skirt 116. In such embodiments, the upper skirt 116 may be unitary with a periphery of the main wall 106. For example, the upper skirt 116 may be deformed or bent from the connection portion of the upper skirt panel 128. The rear bulkhead 102 also has a base structure 138 which is formed from a plurality of panels 138A, 138B, 138C which extend backwards at an angle from the main wall 106 of the rear bulkhead 102 to a lower edge 140 of the rear bulkhead 102. The base structure 138 thus reinforces the central region 122 of the rear bulkhead 102. Such a base structure 138 provides the rear bulkhead 102 with increased support, in comparison to a rear bulkhead with a planar base section. In addition, the panels 138A, 138B, 138C of the base structure 138 extending backwards provides a space in front of the base structure 138 for increased storage and / or locating additional components within the survival cell in front of the rear bulkhead 102. In the illustrated embodiment, the base structure 138 has a rectangular central panel 138C which meets the first and second side panels 120A, 120B of the main wall 106 at a horizontal line in the central region 122 of the main wall 106. The base structure 138 also has two triangular side panels 138A, 138B provided between sides of the central panel 138C and the first and second side panels 120A, 120B of the main wall 106. In other words, a lower edge of the first and second side panels 120A, 120B of the main wall 106 tapers sideways towards a base of the main wall 106, and the two triangular side panels 138A, 138B meet the lower edges of the first and second side panels 120A, 120B at respective diagonal lines. Put another way, the base structure 138 is a trapezium shape when viewed longitudinally (as shown in Figure 3), a trapezium shape when viewed from the top or bottom (as shown in Figure 5A), and a triangular shape when viewed from either side (as shown in Figure 5B). In alternative embodiments, the base structure 138 has a different backwardly extending arrangement (e.g. having more or less than three panels, or having panels of different shape to those illustrated). In the illustrated embodiment, the base structure 138 has first and second slots 142A, 142B in the first and second triangular side panels 138A, 138B for accommodating fixing brackets. In some embodiments, one or more other slots, cut-outs and / or apertures are provided in the base structure 138 for accommodating wiring and / or fixing brackets. In the illustrated embodiment, the first and second triangular side panels 138A, 138E3 of the base structure 138 are integrally formed with the central panel 138C. For example, the base structure 138 may be formed by bending two sides of a trapezium shaped panel. Therefore, the base structure 138 as a whole can be considered as one of the plurality of discrete panels 120A, 120B, 124A, 124B, 128, 138 which are joined together to form the rear bulkhead 102. In alternative embodiments, the plurality of panels 138A, 138B, 138C of the base structure 138 may be discrete components which are joined together (e.g. via overlapping edges of the base structure panels in a similar manner to the overlapping joints between the inclined side skirt panels 124A, 124B and side panels 120A, 120B described above). In the illustrated embodiment, the first and second side panels 120A, 120B have lower flange portions 139A, 139B (as illustrated in Figures 2 and 3) which are angled relative to the respective panels 120A, 120B so that the flange portions 139A, 139B are parallel to and overlap with an upper edge of the base structure 138. In this way, the base structure 138 can be joined together with the first and second side panels 120A, 120B by fastening blind rivets, bolts or other suitable fasteners through the overlapping flange portions 139A, 139B and the upper edges of the panels 138A, 138B, 1380 of the base structure 138. In alternative embodiments, the lower edge of the first and second side panels 120A, 120B is substantially planar and the base structure 138 includes angled flange portions which overlap with the planar lower edges of the first and second side panels 120A,120B. In the illustrated embodiment, at least some of the plurality of discrete panels 120A, 120B, 123, 124A, 124B, 128 have a plurality of recesses (e.g. cut-outs) at their periphery which define apertures 146A to 146H in the assembled rear bulkhead 102 for receiving bars 12 of a roll cage 10 therethrough. The apertures 146Ato 146H allow the rear bulkhead 102 to be located inside a vehicle within the footprint of roll cage 10. For example, a passenger region of the roll cage 10 between A-pillars and B-pillars may be located in front of the rear bulkhead 102 and a rear brace structure of the roll cage 10 may be located behind the rear bulkhead 102. In the embodiment illustrated in Figures 1 and 4, the bars 12 are each formed of a rearward portion 12A and a forward portion 12B connected via an overlap joint 12C. The forward portions 12B ofthe bars 12 passthrough the apertures 146A to 146H. In alternative embodiments, the bars 12 have a different configuration. In particular, the plurality of recesses define: a first aperture 146A at a lower end ofthe first side 114A ofthe rear bulkhead 102; a second aperture 146B at an upper end ofthe first side 114A ofthe rear bulkhead 102; a third aperture 146C between the upper and lower ends ofthe first side 114A ofthe rear bulkhead 102; a fourth aperture 146D at a lower end ofthe second side 114B ofthe rear bulkhead 102; a fifth aperture 146E at an upper end ofthe second side 114B ofthe rear bulkhead 102; a sixth aperture 146F between the upper and lower ends ofthe second side 114B ofthe rear bulkhead 102; and seventh and eighth apertures 146G, 146H proximal to a centre of the upper edge 118, the seventh and eighth apertures 146G, 146H being on opposing sides of a centre line of the rear bulkhead 102. The first and third apertures 146A, 146C are defined by recesses in the first side panel 120A and the first inclined side skirt panel 124A. The second aperture 146B is defined by recesses in the first side panel 120A, the first inclined side skirt panel 124A and the upper skirt panel 128. The fourth and sixth apertures 146D, 146F are defined by recesses in the second side panel 120B and the second inclined side skirt panel 124B. The fifth aperture 146E is defined by recesses in the second side panel 120B, the second inclined side skirt panel 124B and the upper skirt panel 128. The seventh aperture 146G is defined by recesses in the first side panel 120A and the upper skirt panel 128. The eighth aperture 146H is defined by recesses in the second side panel 120B and the upper skirt panel 128. In the illustrated embodiment, the first, third, fourth and sixth apertures 146A, 146C, 146D, 146F are substantially circular, for receiving roll cage bars 12 passing through the rear bulkhead 102 approximately perpendicular to the main wall 106. The second, fifth, seventh and eighth apertures 146B, 146E, 146G, 146H are oval shaped, for receiving roll cage bars 12 passing through the rear bulkhead 102 at an oblique angle relative to the main wall 106. It will be understood that the apertures 146Ato 146H illustrated in Figures 1 to 3 are in a particular arrangement to complement the construction of the illustrated roll cage 10, but that any other suitable arrangement of apertures may be provided to complement other roll cage constructions. It will be understood that the plurality of apertures 146A to 146H being provided by recesses in the discrete panels allows the rear bulkhead to be constructed around an existing roll cage 10, as opposed to having to position the rear bulkhead 102 first and then pass un-assembled roll cage bars 12 through the apertures 146A to 146H to subsequently attach together. Having a plurality of discrete panels 120A, 120B, 123, 124A, 124B, 128,138 which are joined together to form the rear bulkhead 102 (e.g. as opposed to a bulkhead formed as a single piece) allows the rear bulkhead 102 to be inserted through openings in a vehicle body 202 more easily, and to be assembled around vehicle components such as roll cage bars 12 which pass longitudinally through the region occupied by the rear bulkhead 102. Furthermore, prior to assembly within a motor vehicle, the plurality of discrete panels 120A, 120B, 123, 124A, 124B, 128, 138 can be stacked and / or palletised for easier storage and distribution in comparison to a rear bulkhead formed as a single piece. In alternative embodiments the rear bulkhead 102 is formed as a single unitary component or has a different number of panels. For example, a single unitary component may be provided instead of two or more of the rear bulkhead panels 120A, 120B, 123, 124A, 124B, 128, 138 described above, or any of the panels 120A, 120B, 123, 124A, 124B, 128, 138 described above may be split into smaller panels than those illustrated in Figures 1 to 7. It will be understood that in embodiments where the bulkhead is formed as a single unitary component, apertures for receiving roll cage bars 12 may be provided through the single unitary component at the same location as the apertures 146Ato 146H described above. In some embodiments, the inclination angle 0 of the first and second side skirts 112A, 112B is an angle in the range of 20 to 70 degrees with respect to the main wall, e.g. in the range of 30 to 60 degrees or 40 to 50 degrees. In the illustrated embodiment, the inclination angle 0 is substantially 45 degrees, as best illustrated in Figure 4. In some embodiments, the rear bulkhead 102 is formed of sheet metal. In other words, each of the discrete panels 120A, 120E3, 123, 124A, 124E3, 128, 138 described above is formed of sheet metal. Sheet metal provides a simple means of manufacturing the rear bulkhead 102 since the sheet metal can easily be cut, stamped, bent, etc. to form the appropriate shapes. In some embodiments, the sheet metal has a thickness in the range of 1mm to 2mm, e.g. 1,25mm to 1,75mm, e.g. substantially 1.5mm. Such a thickness of sheet metal has been found to provide adequate protection for the survival cell of a motor vehicle, without adding too much weight to the motor vehicle. This is particularly advantageous for high performance motor vehicles (e.g. racing vehicles). In some embodiments, the rear bulkhead 102 is formed of aluminium, e.g. aluminium sheet metal. Aluminium has a good strength to weight ratio which allows the rear bulkhead 102 to provide sufficient protection for the survival cell of a vehicle whilst adding less weight than other materials, such as steel. This is particularly advantageous for high performance vehicles (e.g. racing vehicles). In some embodiments, the aluminium is powder-coated, which allows the performance of the rear bulkhead 102 to be improved, e.g. to increase durability of the aluminium, provide a fire-proof coating, etc. Figure 8 illustrates a vehicle 200 according to an embodiment of the present invention. The vehicle 200 comprises a rear bulkhead 102 as illustrated in Figures 1 to 7. In some embodiments, the vehicle 200 includes a roll cage 10 and the rear bulkhead 102 is provided within a footprint of the roll cage 10. For example, as illustrated in Figure 1, the rear bulkhead 102 may be provided adjacent to and behind a passenger compartment 14 of the roll cage 10. In some embodiments, the vehicle 200 includes a fuel tank 104 behind the rear bulkhead 102. In this way, the rear bulkhead 102 forms a protective barrier for vehicle occupants forward of the bulkhead 102. Referring now to Figure 9, a method of constructing a rear bulkhead 102 as disclosed above is indicated at 300. The method 300 includes the following steps: At step 310, providing a vehicle body 202 (e.g. a monocoque) having one or more openings; At step 320, locating a rear bulkhead 102 as described above inside the vehicle body 202 by inserting the rear bulkhead 102 through the one or more openings; and At step 330, installing the rear bulkhead 102 in position by flexing the at least one inclined skirt against an interior surface of the vehicle body 202. The flexing, or resilient deformation, of the at least one skirt can facilitate installation of the rear bulkhead in the vehicle body to provide protection for occupants in the passenger compartment. In embodiments where the rear bulkhead 102 is formed of a plurality of discrete panels 120A, 120B, 123, 124A, 124B, 128, 138, step 320 may include inserting the individual discrete panels 120A, 120B, 123, 124A, 124B, 128, 138 one at a time into the vehicle body 202 (e.g. vie the openings in the vehicle body 202) and joining the plurality of discrete panels 120A, 120B, 123, 124A, 124B, 128, 138 together to form the rear bulkhead 102. In embodiments where the rear bulkhead 102 includes a plurality of apertures 146A to 146H as described above, step 320 may include locating the rear bulkhead 102 inside the vehicle body 202 such that bars of a roll cage 10 within the vehicle body 202 are received in the plurality of apertures 146A, to 146H. It will be appreciated that various changes and modifications can be made to the present invention without departing from the scope of the present application. Whilst endeavouring in the foregoing specification to draw attention to those features believed to be of particular importance it should be understood that the Applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to and / or shown in the drawings whether or not particular emphasis has been placed thereon.

Claims

1. A rear bulkhead for a survival cell of a motor vehicle, the rear bulkhead defining a main wall configured to separate a passenger compartment from a rear cargo compartment and comprising at least one inclined skirt at a periphery of the rear bulkhead, wherein the at least one inclined skirt extends at an inclination angle to the main wall and is configured to resiliently deform to increase the inclination angle when compressed between the main wall and an internal wall of the motor vehicle during installation of the rear bulkhead.

2. The rear bulkhead of claim 1, wherein the at least one inclined skirt comprises a first inclined side skirt on a first side of the rear bulkhead and a second inclined side skirt on a second side of the rear bulkhead.

3. The rear bulkhead of claim 1 or 2, wherein the at least one inclined skirt comprises an upper inclined skirt at an upper edge of the rear bulkhead; optionally, wherein the upper inclined skirt extends along substantially the entire extent of the upper edge of the rear bulkhead.

4. The rear bulkhead of any preceding claim, wherein the at least one inclined skirt extends at an angle in the range of 20 to 70 degrees with respect to the main wall; optionally, in the range of 30 to 60 degrees; optionally, in the range of 40 to 50 degrees; optionally, substantially 45 degrees.

5. The rear bulkhead of any preceding claim, wherein the at least one inclined skirt comprises a plurality of facets arranged at an angle to each other.

6. The rear bulkhead of any preceding claim, wherein the rear bulkhead is formed of sheet metal; optionally, wherein the sheet metal comprises a thickness in the range of 1mm to 2mm, preferably 1.25mm to 1.75mm, preferably substantially 1.5mm.

7. The rear bulkhead of claim 6, wherein the at least one inclined skirt is unitary with at least part of the main wall.

8. The rear bulkhead of any preceding claim, wherein the rear bulkhead comprises a plurality of discrete panels which are joined together to form the rear bulkhead.

9. The rear bulkhead of claim 8, wherein at least some of the plurality of discrete panels have a plurality of recesses at their periphery which define apertures in the assembled rear bulkhead for receiving roll cage bars therethrough.

10. The rear bulkhead of any preceding claim, wherein the at least one inclined skirt comprises a plurality of discrete skirt panels.

11. The rear bulkhead of any one of claims 8 to 10, wherein the plurality of discrete panels comprises a first side panel which extends from a central region of the rear bulkhead towards a first side of the rear bulkheadand a second side panel which extends from the central region to a second side of the rear bulkhead, wherein the first and second side panels define over 50% of the area of the main wall, and wherein a first inclined side skirt panel is connected to the first side panel at the first side of the rear bulkhead and / or a second inclined side skirt panel is connected to the second side panel at the second side of the rear bulkhead and / or an upper inclined skirt panel is connected to the first and / or second side panels at an upper edge of the rear bulkhead.

12. The rear bulkhead of any preceding claim, wherein the at least one inclined skirt comprises a nonlinear periphery for fitting around structures and / or components of a vehicle body.

13. The rear bulkhead of any preceding claim, further comprising a base structure having a plurality of panels which extend backwards at an angle from the main wall of the rear bulkhead to a lower edge of the rear bulkhead to reinforce a central region of the rear bulkhead; optionally, wherein the base structure comprises one or more slots, cut-outs and / or apertures for accommodating wiring and / or fixing brackets.

14. A vehicle comprising the rear bulkhead of any preceding claim.

15. A method of constructing a rear bulkhead for a survival cell of a vehicle, the method comprising:(a) providing a vehicle body having one or more openings;(b) locating the rear bulkhead of any of claims 1 to 13 inside the vehicle body by inserting the rear bulkhead through the one or more openings; and(c) installing the rear bulkhead in position by flexing the at least one inclined skirt against an interior surface of the vehicle body.

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