Instrument panel cover

Abstract

Aspects of the present invention relate to instrument panel cover (100, 200, 300) for a vehicle. The instrument panel cover (100, 200, 300) includes a substrate (102), the substrate (102) comprising a loudspeaker recess or opening (106) and an airbag exit region (108). The instrument panel cover (100, 200, 300) also includes an outer layer (104) comprising a knitted fabric covering at least the loudspeaker recess or opening (106) and the airbag exit region (108). The outer layer (104) includes a region of weakness (134, 148) overlying and / or adjacent to the airbag exit region (108), the region of weakness (134, 148) being configured to rupture in the event of airbag deployment.

Description

[0001] INSTRUMENT PANEL COVER

[0002] TECHNICAL FIELD

[0003] The present disclosure relates to an instrument panel cover. Aspects of the invention relate to an instrument panel cover for a vehicle, an outer layer for use with an instrument panel cover, and a vehicle comprising an instrument panel cover.

[0004] BACKGROUND

[0005] It is known to provide an instrument panel cover for a vehicle. An instrument panel cover typically extends along a lower edge of the vehicle’s windscreen, and extends across the width of a vehicle interior. The upper surface of the instrument panel cover is exposed to the environment within the vehicle cabin. In some jurisdictions, the term “dashboard” may be used to refer to this component and / or region.

[0006] It is an aim of the present invention to address one or more of the disadvantages associated with the prior art.

[0007] SUMMARY OF THE INVENTION

[0008] Aspects and embodiments of the invention provide an instrument panel cover for a vehicle, an outer layer for use with an instrument panel cover, and a vehicle comprising an instrument panel cover as claimed in the appended claims.

[0009] According to an aspect of the present invention there is provided an instrument panel cover for a vehicle, the instrument panel cover comprising: a substrate, the substrate comprising an airbag exit region; and an outer layer comprising a fabric, optionally a knitted fabric, covering at least the airbag exit region, the outer layer comprising a region of weakness overlying and / or adjacent to the airbag exit region, the region of weakness being configured to rupture in the event of airbag deployment.

[0010] According to an aspect of the present invention there is provided an instrument panel cover for a vehicle, the instrument panel cover comprising: a substrate, the substrate comprising: a loudspeaker recess or opening; and an airbag exit region; and an outer layer comprising a fabric covering at least the loudspeaker recess or opening and the airbag exit region, the outer layer comprising a region of weakness overlying and / or adjacent to the airbag exit region, the region of weakness being configured to rupture in the event of airbag deployment.

[0011] According to a further aspect of the present invention there is provided an instrument panel cover for a vehicle, the instrument panel cover comprising: a substrate, the substrate comprising: a loudspeaker recess or opening; and an airbag exit region; and an outer layer comprising a knitted fabric covering at least the loudspeaker recess or opening and the airbag exit region, the outer layer comprising a region of weakness overlying and / or adjacent to the airbag exit region, the region of weakness being configured to rupture in the event of airbag deployment.

[0012] The use of a knitted fabric with a region of weakness may allow for a durable instrument panel cover while still allowing rupturing in response to airbag deployment.

[0013] The region of weakness may be substantially invisible to a viewer of the instrument panel cover. This may allow for a more aesthetically pleasing instrument panel cover.

[0014] The region of weakness may extend parallel to a line of weakness in the warp or weft direction of the knitted fabric. This may reduce the forces required for rupturing the region of weakness and / or reduce the amount of weakening required to enable the rupturing.

[0015] The region of weakness may comprise a portion that extends along part of a width of the instrument panel cover. This may assist in the deployment of an airbag in a desired direction and / or manner.

[0016] The region of weakness may comprise an incision cut at least partially into the knitted fabric. This may provide a convenient and / or predictable weakening method, while optionally rendering the region of weakness not visible on an outer surface of the outer layer.

[0017] The knitted fabric may comprise at least one thread, and the region of weakness may comprise at least a partial cut through at least some of the threads. This may provide a convenient and / or predictable weakening method, while optionally rendering the region of weakness not visible on an outer surface of the outer layer.

[0018] The region of weakness may comprise one or more laser cuts.

[0019] The region of weakness may comprise a line of laser-cut through-holes. Such through-holes may be elongate in the direction of the line. Optionally, the through-holes may be spaced apart by a distance less than their length.

[0020] The region of weakness may be formed on a substrate side of the outer layer.

[0021] A technical back of the knitted fabric may be used to provide an outer surface of the outer layer. By using the technical back of the knitted fabric to provide the outer surface of the outer layer, the technical face of the fabric having raised geometric patterns forms the substrate side of the outer layer on which the region of weakness may be at least partially formed.

[0022] The region of weakness may extend at least partially across a central region of the airbag exit region. This may reduce the required length, number, and / or area of the line or region of weakness, thereby improving durability of the outer layer. The instrument panel cover may comprise a grille extending overthe loudspeaker recess or opening, the grille supporting the outer layer where it covers the loudspeaker recess or opening. This may reduce visibility of the location of the recess or opening by reducing or substantially eliminating sagging of the outer layer in the vicinity of the loudspeaker recess or opening.

[0023] The outer layer may be adhered to at least part of the substrate. For example, the outer layer may be adhered to the substrate with an adhesive. This may reduce movement of the outer layer relative to the substrate, which may improve durability.

[0024] The outer layer may be adhered to the substrate with a contact adhesive.

[0025] The grille may comprise apertures, and the outer layer may be adhered to the substrate and the grille, there being no adhesive on the outer layer where it crosses the apertures. This may reduce movement of the outer layer relative to the substrate and grille, which may improve durability, and may also reduce sagging of the outer layer, where it crosses the apertures, during exposure to a high temperature environment.

[0026] The substrate may comprise: a structural layer; and a compressible interface layer disposed between the outer layer and the structural layer.

[0027] The interface layer may make the outer layer more resilient to human touch.

[0028] The interface layer may comprise a material having physical characteristics that allow the interface layer to rupture in the event of airbag deployment. This may reduce or avoid the need for line(s) and / or region(s) of weakness in / on the interface layer.

[0029] According to a further aspect of the present invention there is provided an outer layer for use with the instrument panel cover of any aspect.

[0030] According to a further aspect of the present invention there is provided a vehicle comprising the instrument panel cover of any aspect.

[0031] 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

[0032] One or more embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0033] Figure 1 shows a vehicle in accordance with an embodiment of the invention;

[0034] Figure 2 shows a schematic forward-looking perspective view of an interior of the vehicle, showing an instrument panel cover in accordance with an embodiment of the invention;

[0035] Figure 3 shows a schematic cross-section through a portion of the instrument panel cover of Figure 2;

[0036] Figure 4 shows a top-down schematic view of a substrate of the instrument panel cover of Figure 2;

[0037] Figures 5 to 7 show schematic cross-sections through loudspeaker apertures of alternative embodiments of the instrument panel cover of Figure 2;

[0038] Figure 8 shows a schematic cross-section through an airbag exit region of the instrument panel cover of Figure 2, as indicated by lines VII I— VI 11;

[0039] Figure 9 shows a top-down view of a portion of an outer layer forming part of the instrument panel cover of Figure 2;

[0040] Figure 10 shows a schematic cross-section through the airbag exit region of Figure 8, during deployment of the airbag;

[0041] Figure 11 shows a schematic cross-section through a portion of an alternative embodiment of an instrument panel cover;

[0042] Figure 12 shows a top-down view of a grille for covering a loudspeaker aperture of an instrument panel cover; Figure 13 shows a schematic cross-section through a loudspeaker aperture of an instrument panel cover, incorporating the grille of Figure 12;

[0043] Figures 14 to 17 show perspective views of alternative grills for covering a loudspeaker aperture of an instrument panel cover;

[0044] Figure 18 shows a schematic cross-section through loudspeakers aperture of an alternative embodiment of an instrument panel cover.

[0045] Figure 19 shows a schematic view of a first type of knitted fabric; and Figure 20 shows a schematic view of a second type of knitted fabric.

[0046] DETAILED DESCRIPTION

[0047] An instrument panel cover in accordance with an embodiment of the present invention is described herein with reference to the accompanying Figures. The instrument panel cover can be installed within a vehicle, such as vehicle 400 shown in Figure 1 , such that it covers an instrument cluster and other components housed in front of the driver and front-passenger of the vehicle. A vehicle instrument cluster provides visible information to a driver of the vehicle. For example, an instrument cluster can show the vehicle’s speed and the status of various vehicle systems. While instrument clusters have historically included individual gauges or dials to provide information to the driver, these have increasingly been replaced by multi-function panel displays.

[0048] The instrument panel cover can also extend over other vehicle components, such as a glovebox, entertainment / navigation system, heating and ventilation ducting, and other components that are known to the skilled person. The instrument panel cover can also cantilever over the instrument cluster and other displays / controls to protect them from ambient light and improve legibility. The upper surface of the instrument panel cover is exposed to the environment within the vehicle cabin. In some jurisdictions, the term dashboard may be used to refer to this component and / or region.

[0049] Referring to Figure 2, there is shown an interior of a vehicle, such as the vehicle 400. The interior includes an instrument panel cover 100. The instrument panel cover 100 extends across the width of the interior of the vehicle 400, underneath a windscreen 168. The instrument panel cover 100 extends above an instrument cluster in the form of a display screen 170, an entertainment system interface 172, a glovebox door 174, and vents 176.

[0050] As best shown in Figure 3, the instrument panel cover 100 includes a substrate 102. In the embodiment of Figures 2 to 4, the substrate 102 comprises a structural layer 112 overlaid with a compressible interface layer 114. The structural layer 112 provides a structural base that can be mounted to suitable supports and / or mounts (not shown) within the vehicle 400 during manufacture, using, for example, clips (not shown), fasteners (not shown), and / or adhesives.

[0051] The structural layer 112 is formed from injection-moulded glass-reinforced polypropylene (PP-GF) and the compressible interface layer 1 14 is formed from a polyurethane foam, although different materials can be used in other embodiments.

[0052] The substrate 102 is covered by an outer layer 104, which defines the outer / upper surface of the instrument panel cover 100 that is visible to occupants of the vehicle. The outer layer 104 comprises a knitted fabric covering that extends over the upper surface of the interface layer 114. An example of such a knitted fabric is a Swiss Pique Double Jersey Circular Knit. The outer layer 104 can be of unitary construction, or can be formed from two or more separate panels that are joined together by stitching, adhesives, or any other suitable joining method known to the skilled person.

[0053] An optional layer (not shown) can be positioned between the interface layer 114 and the outer layer 104, to prevent uncured polyurethane foam leaking into the voids of the knitted fabric of the outer layer 104 during manufacture of the instrument panel cover 100. One example of such a layer is a skin 166 shown in Figure 11 and described in more detail below. Other alternative optional layers will suggest themselves to the skilled person.

[0054] There are several ways to manufacture the instrument panel cover 100. For example, the structural layer 112 and the outer layer 104 can be used to line opposite halves of a mould during manufacture of the substrate 102. Uncured polyurethane is injected into the void defined between the upper surface of the structural layer 112 and the lower surface of the outer layer 104, and allowed to cure.

[0055] Alternatively, the outer layer 104 is used to line one half of a mould, with the outer layer’s underside (or any optional layer) facing up. Uncured polyurethane foam is poured over the underside of the outer layer 104. The structural layer 112 is positioned in the other half of the mould and pressed down onto the polyurethane foam. This squeezes the polyurethane foam such that it is distributed throughout the void between the underside of the outer layer 104 and the upper surface of the structural layer 112. The polyurethane foam is allowed to cure.

[0056] In either case, the surfaces of the structural layer 112 and / or the outer layer 104 (or optional layer) may need to be heat-treated, such as with a flame or plasma treatment, to activate the surfaces such that the polyurethane foam will stick to them.

[0057] Both approaches allow for consistent foam thickness, which ensures a relatively smooth upper surface of the outer layer 104.

[0058] Figure 4 shows the substrate 102 with the outer layer 104 removed for clarity. With the outer layer 104 removed, it can be seen that the substrate 102 includes a central loudspeaker opening 106 formed through the substrate 102. The loudspeaker opening 106 is configured to receive at least one loudspeaker driver (not shown). Each loudspeaker driver can be attached to the substrate 102 using fasteners (not shown) such as screws, clips, orthe like, an adhesive and / or sealant (not shown), and / or any other suitable attachment means.

[0059] Depending upon the implementation, each loudspeaker can be installed from above or beneath the substrate 102. Figure 5 shows an example of a loudspeaker 116 installed at the loudspeaker opening 106. An outer edge of the loudspeaker 1 16 is supported within an annular recess 118 extending around an upper periphery of the opening 106.

[0060] Figure 6 shows a further example of a loudspeaker 1 16 installed into a different embodiment of the loudspeaker opening 106, in which the annular recess 118 extends around a lower periphery of the opening 106. In contrast to the arrangement of Figure 5, the loudspeaker 116 in Figure 6 is installed from underneath the substrate 102. In Figures 5 and 6, attachment means (such as those described above) are omitted for clarity.

[0061] In alternative embodiments, the loudspeaker can be mounted to a support structure (not shown) of the vehicle, such that it is aligned with corresponding loudspeaker opening(s) 106 when the instrument panel cover 100 is installed.

[0062] In the implementation shown, there is a single loudspeaker opening 106 positioned centrally on the instrument panel cover 100. It will be appreciated that one or more additional loudspeaker openings can be provided in other embodiments, and that the location, sizes, and shapes of the opening(s) can be selected to suit the loudspeakers that are installed at those openings.

[0063] The drivers used for the loudspeaker(s) can be of any suitable type, including dynamic drivers, electrostatic drivers, panel drivers (including electrostatic panel drivers), or any other driver type or combination thereof. In other embodiments, more than one loudspeaker driver can be provided at each loudspeaker opening 106. As also shown in Figure 4, the substrate 102 includes an airbag exit region 108. The airbag exit region 108 is positioned in front of the passenger seat (not shown). The steering wheel 146 (see Figure 2) includes its own airbag for the driver, and so no airbag is provided on the driver’s side of the instrument panel cover 100.

[0064] The airbag exit region 108 is configured to allow airbag deployment through the substrate 102 and outer layer 104, as described in more detail below. Each airbag module (not shown) can be attached to the substrate 102 using fasteners (not shown) such as screws, clips, or the like, an adhesive and / or sealant (not shown), and / or any other suitable attachment means.

[0065] Depending upon the implementation, the airbag modules can be installed from above or beneath the substrate 102, for example as was described above in relation to the loudspeakers. It will be understood that the mounting requirements for airbag modules may differ from those of loudspeakers. For example, there may be safety and / or legal requirements that limit the ways in which airbag modules must be mounted, including the strength of the mounting points and fasteners. The skilled person is familiar with such requirements, and so they are not described in detail here.

[0066] In alternative embodiments, one or more of the airbag modules can be mounted to a support structure (not shown) of the vehicle, such that they are aligned with a corresponding airbag exit region 108 when the instrument panel cover 100 is installed.

[0067] Returning to Figure 2, region 130 indicates the position of the loudspeaker opening 106 underneath the outer layer 104. Similarly, region 132 indicates the position of the airbag exit region 108 underneath the outer layer 104.

[0068] In alternative embodiments, the loudspeaker opening 106 can be replaced by a loudspeaker recess. For example, Figure 7 shows a loudspeaker 116 installed into a loudspeaker recess 120. The loudspeaker recess 120 is partly defined by a wall 122 that extends downwardly from the underside of the substrate 102. The wall 122 can be a separate element or component that is attached to the substrate 102 in any suitable manner, as shown in Figure 7. Alternatively, the wall 122 may be moulded or otherwise formed as a unitary part of the substrate 102.

[0069] The volume of the loudspeaker recess 120 can be selected to form a sealed, tuned enclosure having characteristics that are compatible with the requirements of the loudspeaker 116. Optionally, one or more ports or apertures (not shown) may be formed in the wall 122 and / or the substrate 102, such that the loudspeaker recess 120 acts as a ported tuned enclosure for the loudspeaker 116. The properties and behaviour of sealed and ported enclosures are well known to the skilled person, and so are not described in detail here.

[0070] The instrument panel cover 100 optionally includes an airbag recess extending underneath the substrate 102. For example, Figure 8 shows an airbag module 124 installed into an airbag recess 126. The airbag recess 126 is defined by a wall 128 that extends downwardly from the underside of the substrate 102. The wall 128 is a separate element or component attached to the substrate 102 in any suitable manner, as shown in Figure 8. Alternatively, the wall 122 may be moulded or otherwise formed as a unitary part of the substrate 102.

[0071] Figure 9 shows a top-down view of the outer layer 104, showing the region 132. A region of weakness, in the form of linear regions, is formed in the outer layer 104. The linear regions are positioned to overlie the airbag exit region 108 when the outer layer 104 is installed on the substrate 102, as described in more detail below. The linear regions include a horizontal (relative to the orientation of Figure 9) line of weakness 134 that extends across the width of the airbag exit region 108. The line of weakness 134 also extends through a central region of the airbag exit region 108. For example, at least 50% of the length of the line of weakness 134 can extend within a central region of the airbag exit region. In this context, “central” means within a middle 25% (measured along a line parallel to the direction of vehicle travel) of the airbag exit region. Such a central region is shown as a hatched region 136 in Figure 9.

[0072] The linear regions also include further lines of weakness 148, which extend approximately normally from the ends of the line of weakness 134 towards the edge of the region 132. Together, the lines of weakness 134 and 148 offer a predetermined pattern along which the outer layer 104 will rupture in the event of airbag deployment.

[0073] The further lines of weakness 148 do not necessarily reduce the tensile strength of the knitted fabric as much as the horizontal lines of weakness 134. However, due to the way in which the knitted fabric ruptures as the airbag is deployed, it is more effective for the horizontal line of weakness 134 to be formed along the inherent lines of weakness of the knitted fabric.

[0074] In other embodiments, the region of weakness can take other shapes and forms. For example, the region of weakness can include linear regions extending in different directions and having different lengths to those illustrated in Figure 9. In addition, different combinations of linear regions to those shown in Figure 9 can be employed.

[0075] In some embodiments, the region of weakness (i.e., the linear regions 134 and 148) is formed on a substrate side of the outer layer 104, which enables the region of weakness to be invisible, or at least difficult to see, from within the vehicle cabin. This approach may be used when the method of forming the region of weakness leaves a visible mark. For example, a partial depth cut made with a blade may leave a visible line, in which case it is necessary to position the cut on the substrate side of the outer layer 104. Where the weakening process does not leave a visible mark (e.g., is the result of invisible incisions or perforations) on either side of the knitted fabric, it is not necessary to perform the weakening from any particular side of the knitted fabric, and either side of the knitted fabric can be exposed.

[0076] In some embodiments, a technical back of the knitted fabric used for the outer layer 104 may be used to provide an outer surface of the outer layer 104. As would be understood by a person skilled in the relevant art, knitted fabrics typically comprise a technical face and a technical back. The technical face of the fabric, sometimes called the ‘right side’ or ‘face’, is the side of the knitted fabric that consists of the face loops (when the new loop emerges through the old loop from the back to the face side). Figure 19 illustrates an example of a knitted fabric viewed from the technical face side of the fabric. The technical face of a knitted fabric shows the knit pattern and often consists of raised geometric patterns. The technical back of the fabric, sometimes called the ‘wrong side’ or back, is the side of the knitted fabric that consists of the back loops, including floats and tucks, that are typically not meant to be seen. For knitted fabrics produced on a circular knitting machine, the technical back of the fabric is typically created by the dial needles. The technical back of a knitted fabric is usually flatter than the technical face.

[0077] By using the technical back of the knitted fabric to provide the outer surface of the outer layer 104, the technical face of the fabric having raised geometric patterns forms the substrate side of the outer layer 104 on which the region of weakness may be formed. For example, the lines of weakness 148, 178 may be formed in / across the raised geometric patterns of the technical face of the fabric.

[0078] The substrate 102 at the airbag exit region 108 is configured to allow the airbag 124 to burst through it during airbag deployment. In this case, the substrate 102 incorporates regions of weakness in the form of lines of weakness 178 that are near the regions of weakness in the underside of the outer layer 104. As best shown in Figure 8, the lines of weakness 178 adjacent to the left and right edges of the region 132 are inset about 3 mm from the lines of weakness 148, and the line of weakness 178 extending horizontally through the region 132 is parallel to and directly underneath the line of weakness 134.

[0079] In the example shown in Figures 8 to 10, additional lines of weakness 180 are also provided in the substrate 102, along the upper and lower horizontal edges of the airbag exit region 108 as shown in Figure 9. The additional lines of weakness 180 allow the substrate 102 to fracture as the airbag deploys, as described in more detail below.

[0080] The various lines of weakness 134, 148, 178, 180 allow the substrate 102 to fracture with the outer layer 104 as the airbag deploys, as described in more detail below.

[0081] The lines of weakness 178, 180 can be formed in any suitable manner and at any suitable time in the manufacturing process. For example, the lines of weakness 178, 180 can be laser cut through from the underside of the substrate. Mechanical weakening with a blade, die, punch, drill, or other tool(s) may also be used. In other implementations, the lines or regions of weakness may be moulded or formed into the substrate during manufacture. The lines of weakness can be formed before or after the outer layer 104 has been applied to the substrate 102. Where the lines of weakness are formed after the outer layer 104 has been applied to the substrate 102, care must be taken not to cut through the outer layer 104 if there is the possibility of visible marking.

[0082] In other implementations, the substrate 102 does not extend across any or all of the recess (or aperture, where the substrate 102 does not include an attached or integral recess such as recess 126). In that case, a separate component or components (not shown) can be used to cover the airbag exit region 108 and provide a base for the outer layer 104 in that region. Such component(s) can be attached to the substrate in any suitable way. For example, they can be welded or bonded to the substrate. Such component(s) (or their attachment to the substrate) can define a hinge about which the component(s) rotate during airbag deployment.

[0083] Figure 10 shows a schematic cross-sectional view of the airbag module 124 during deployment of an airbag 182. It can be seen that expansion of the airbag 182 has caused the regions of weakness 134, 148, 178, and 180 to rupture. The unruptured outer layer 104 lying over the regions of weakness 180 acts as a hinge for each of the pieces 184, 186 of the substrate 102 that are now detached from the rest of the substrate 102. This allows the pieces 184, 186 to hinge up and out of the way of the deploying airbag 182.

[0084] It will be appreciated that other patterns of lines and regions of weakness can be used to provide different airbag deployment arrangements.

[0085] Rather than relying on the outer layer 104 to act as a hinge, a separate hinge (not shown) may be used. For example, a polymer web or mesh can be incorporated into the upper surface of the substrate 102, during moulding of the substrate, for example. The web or mesh is positioned where it is intended to act as a hinge. The substrate 102 can be weakened along the web or mesh in any suitable manner to form the additional line(s) of weakness 180, including by laser cutting or mechanical weakening of the substrate 102 after the substrate 102 has been manufactured, or by moulding the line or region of weakness into the underside of the substrate 102 during manufacture. When the airbag 182 deploys, the web or mesh acts as a hinge. By being incorporated into the substrate 102 during manufacture, the web or mesh prevents the pieces 184, 186 of the substrate 102 from separating from the surrounding substrate 102 in response to forces generated during airbag deployment.

[0086] As mentioned above, the outer layer 104 comprises a knitted fabric covering that extends over the upper surface of the compressible interface layer 114. In this context, “knitted” takes the ordinary meaning of the term in the field of fabric construction. In general, knitted fabric is manufactured differently to woven or nonwoven fabrics. In particular, the thread in knitted fabric follows a meandering path, with adjacent rows (or columns) of threads interlocking with each other. In contrast, woven fabrics use threads extending at (typically) right angles to each other without significant meandering, while non-woven fabrics can have thin polymer threads orientated in random directions relative to each other.

[0087] Two common types of knitted fabric are weft-knit fabric and warp-knit fabric. In a weft-knit fabric, the threads extend in a direction that is generally at right angles to the direction of fabric production, and meander side to side around that direction. Figure 19 shows an example of a weft-knit fabric 150, in which the direction of fabric production is indicated by arrow 152. Thread 154 meanders across the fabric 150 in a direction generally at right angles to the arrow 152.

[0088] In a warp-knit fabric, the threads extend in a direction that is generally parallel to the direction of fabric production, and meander side to side around that direction. Figure 20 shows an example of a warp-knit fabric 156, in which the direction of fabric production is indicated by arrow 158. Thread 160 meanders through the fabric 156 in a direction generally parallel to the arrow 158. Compared to woven or non-woven fabrics, knitted fabrics tend to have strength characteristics that vary with orientation, especially where threads of the fabric are weakened. In particular, a partial cut, or a series of spaced-apart full-depth cuts, through at least some of the threads, made in the knitted fabric in a direction parallel, or at right angles, to the production direction of the fabric (and as described in more detail below) will typically provide the greatest weakening effect. Additionally, such cut(s) made in the knitted fabric in a direction at right angles to the direction giving the greatest weakening effect will typically provide the second greatest weakening effect.

[0089] The specific impact of the direction along which the cut(s) are made on the weakening effect may vary depending on the knitting type (i.e., weft or warp), and the particular stitches and material used, and can be determined by the skilled person by simple testing. It may be that either of these directions provides sufficient weakening, in which case the direction can be chosen based on any suitable basis, such as aesthetics, ease of production, ease of installation, etc.

[0090] The region of weakness in the outer layer 104 can be formed in any suitable manner.

[0091] In one embodiment, the linear regions 134 and 148 extend parallel to a linear region of inherent weakness in the warp or weft direction of the knitted fabric, as described above. A “linear region of weakness” in this context means a line extending parallel or normal to the direction of fabric production, along which the fabric is easier to tear than at a 90° offset to that line.

[0092] The linear regions 134 and 148 can be formed or generated in any suitable manner. For example, the linear regions 134 and 148 can be formed by cutting an incision at least partly into the knitted fabric. For example, one or more threads along the linear region of weakness may be at least partly cut through.

[0093] In Figure 19, one of the inherent lines of weakness is indicated by horizontal dashed line 162. In Figure 20, one of the inherent lines of weakness is indicated by vertical dashed line 164. In each case, a cut can be made where the lines 162, 164 encounter the respective threads 154, 160. It will be appreciated that many additional inherent lines of weakness can be drawn parallel to the dashed lines 162, 164.

[0094] Partial cutting through the threads can be achieved in any suitable manner. For example, partial cutting can be achieved with a blade configured to make an incision involving a partial cut through the thread(s) as it passes. An alternative to the use of a blade is laser cutting, in which a laser is used to cut a series of through- holes through the fabric. The through-holes are small enough that they are not visible, but a sufficient density of the through-holes ensures that the knitted fabric is sufficiently weakened that it predictably ruptures during airbag deployment. EXAMPLE

[0095] The effect on tensile strength of laser-cut through-holes was tested on swatches of polyester weft-knit fabric approximately 0.8-0.9 mm thick and 50 mm wide. Two sample swatches were prepared: one extending in the “across roll” direction and the other extending in the “with roll” direction.

[0096] A line of elongate (in plan view) through-holes was cut across the full width of each swatch. Each through-hole was 0.45 mm long in the direction of the line. The through-holes were spaced apart from each other along the line by 0.25 mm.

[0097] A tensile strength test was performed by pulling each swatch at right angles to the line of weakening. The changes in tensile strength are summarised in the following table:

[0098] The table shows that, in this example, the relative weakening effect was similar in both directions. However, the substantially lower tensile strength in the “with roll” direction means that the resultant force required to break the swatch was only 141 N.

[0099] In other embodiments, the laser can be controlled to leave a specific residual thickness for each thread that it cuts. The residual thickness is selected to give the required weakening while ensuring the weakening is not visible from the upper side of the upper layer 104.

[0100] Optionally, tracking (such as optical or laser-based tracking) can be used such that the cut(s) are made along a single line (or a small number of lines) of weft or warp. This may help enhance the weakening effect of the cuts while reducing the chance of the cuts causing a visible effect on the upper side of the outer layer 104. Alternatively, some meandering of the cut(s) across adjacent rows / columns in the direction of the cut(s) may provide an acceptable result, in terms of both visibility and strength.

[0101] The knitted fabric can be orientated such that the weft / warp directions of the inherent lines of weakness in the knitted fabric (i.e., before performing the weakening process(es) described above) extend laterally across the vehicle when the instrument panel cover 100 is installed in the vehicle. This direction is indicated by arrow 140 in Figure 4. This allows for at least some of the region of weakness formed in the outer layer to be arranged parallel to the inherent lines of weakness in the knitted fabric, which may improve rupturing along the region of weakness where it is parallel to the inherent lines of weakness.

[0102] This arrangement is particularly suitable for weakening the outer layer 104 along lines in the outer layer 104 through which an airbag must burst during deployment. For example, as shown in Figure 9, it may be important that the central, horizontally-extending (relative to the orientation of Figure 9) linear region 134 is able to rupture more easily and / or predictably than the other linear region 148, in response to explosive expansion of the airbag behind it. Orientating the knitted fabric of the outer layer 134 such that the inherent weakness of the knitted fabric is parallel to the horizontal linear region 134 enhances the tearability of the fabric along the linear region 134, leading to improved and / or more predictable tearing.

[0103] Optionally, the compressible interface layer 114 can be formed of a fabric, foam, or other material that, in response to airbag deployment, is sufficiently easily torn or ruptured as the region of weakness. This helps encourage tearing of the outer layer 104 along the region(s) of weakness.

[0104] Alternative embodiments can include a skin between the interface layer 114 and the outer layer 104. For example, Figure 11 shows a cross section through an alternative embodiment of an instrument panel cover 200. The instrument panel cover 200 shares several features with the instrument panel cover 100, and like features are designated with the same reference numbers.

[0105] The substrate 102 of the instrument panel cover 200 includes a skin 166 that underlies the outer layer 104. The skin 166 can be formed from, for example, an injection-moulded thermoplastic elastomer (TPE). The upper surface of the skin 166 provides a smooth base for the outer layer 104. The outer layer 104 is adhered to the upper surface of the skin 166 using, for example, a spray or hot-melt polyurethane adhesive.

[0106] When the interface layer 114 takes the form of an in-situ moulded layer (such as a foam layer), the structural layer 112 and the skin 166 can be used to line opposite halves of a mould during manufacture of the substrate 102. Uncured polyurethane foam can be injection-moulded or poured onto the skin 166, in a similar manner as was described above in relation to the embodiment of Figures 2 to 4.

[0107] A challenge raised by the use of knitted fabric for the outer layer is the stretchability of knitted fabrics relative to woven or non-woven fabrics. Due to the meandering path taken by the threads in knitted fabrics (compared with the relatively straight paths of woven fabrics, for example), knitted fabrics tend to be less dimensionally stable. As such, knitted fabrics can tend to stretch or sag more easily than a woven fabric for a given thread thickness. This can become an issue where the outer layer 104 covers openings such as the loudspeaker opening 106. For example, if stretched over a large opening, the outer layer 104 will tend to sag slightly, and to show the edges of the opening. To reduce the visible impact of such sagging, a grille may be provided over any openings that are large enough to cause potential issues.

[0108] For example, Figures 12 and 13 show an alternative embodiment in which the loudspeaker opening 106 is circular. A circular grille 142 is positioned within the loudspeaker opening 106 above the loudspeaker 116, such that an upper surface of the grille 142 is flush with the surrounding upper surface of the substrate 102. The grille 142 includes apertures 144, through which sound from the loudspeaker 116 can pass. The solid portions of the grille 142 support the underside of the outer layer 104, such that the upper surface of the outer layer 104 where it lies over the grille 142 is flush and continuous with the surrounding upper surface of the outer layer 104. Each aperture 144 is around 6 mm in diameter, and the apertures 144 are spaced from each other by around 3 mm.

[0109] The size and shape of the apertures 144 can be selected such that the overlying outer layer 144 does not visibly sag into the apertures. This results in a smooth appearance, which may renderthe loudspeaker opening 106 invisible or at least difficult to see beneath the outer layer 104. In the context of the present application, “invisible” can mean not visible to a human eye having 20 / 20 vision, at a distance of at least 0.25 m, and with the upper surface of the outer layer 104 illuminated by a uniform light source at a minimum luminance of 2000 Lux.

[0110] Typically, the outer layer is adhered to the underlying substrate. The outer layer may face challenging environmental conditions, such as extremes of heat and cold. As such, the adhesives used to adhere the outer layer to the structural layer are typically contact adhesives, which tend to retain their adhesive qualities relatively well even in challenging environmental conditions. Contact adhesives are applied to both surfaces to be joined. After the adhesive becomes tacky, the surfaces are brought together under pressure to permanently join them.

[0111] If contact adhesive is used over the entire underside of the outer layer 104, the portions of the outer layer 104 that extend across apertures (such as the apertures 144 of the grille 142) will have a layer of contact adhesive on their underside. In hot conditions, the adhesive can soften. The combination of the adhesive softening, the additional weight of the adhesive, and the relative stretchability of the fabric of the outer layer 104, can cause slight sagging of the outer layer 104 into the apertures 144, even where the size of the apertures is such that such sagging would not occur in the absence of the adhesive. This may result in a slightly dimpled appearance when viewed from above. When conditions cool, the adhesive becomes firm again, and the sagging becomes permanent. Cycles of heating and cooling over time can gradually increase the sagging, resulting in any dimpled appearance becoming worse.

[0112] One way of reducing sagging due to the existence of contact adhesive layer on the underside of the outer layer 104 issue is to mask, during application of the contact adhesive layer, the region of the outer layer 104 that overlaps the apertures 144 of the grille 142. As a result, the contact adhesive is not applied to the outer layer 104 in that region.

[0113] A disadvantage of this approach is that the outer layer 104 will not be adhered to the grille within the region lacking the contact adhesive, but this may be preferable to long term sagging within the apertures. One way of addressing this disadvantage is to apply an ordinary (i.e., single surface) adhesive to the solid parts of the grille before applying the outer layer 104 to the substrate 102. Although such adhesives may underperform contact adhesives, the fact that the rest of the outer layer is adhered to the substrate with contact adhesive tends to stabilise the outer layer in the region around the grille. This means that the adhesive on the grille can be of lower strength, or have worse performance in challenging conditions, than the contact adhesive without there being too great an overall impact on adhesion of the outer layer. Another way of reducing such sagging is to use an adhesive that is applied only to the upper layer of the substrate 102. Such an adhesive can be applied across the both the upper surface of the substrate 102 and the upper surface of the grille 142. As a result, the outer layer 104 will be adhered at all points at which it contacts the upper surface of the substrate 102 and the upper surface of the grille 142, but there is no adhesive on the portions of the outer layer 104 that extend across apertures. As such, sagging is reduced.

[0114] Figures 14 to 17 show various alternative embodiments of grilles 142, using different sizes and shapes of apertures 144. The sizes and shapes of the apertures 144 can be chosen based on requirements such as strength, stiffness, heat- and cold-resistance, ease and price of manufacture, openness (i.e., the proportion of the area of the grille that is open due to apertures), attenuation (both overall and frequency based), and compatibility with, e.g., any adhesive intended to be used with the grille.

[0115] An alternative to using a grille is to provide multiple speaker openings 106 per speaker. That is, instead of a single opening 106 in the substrate, as was described in relation to Figures 2 to 7, multiple openings can be provided. For example, Figure 18 shows a cross section through an alternative embodiment of an instrument panel cover 300. The instrument panel cover 300 shares several features with the instrument panel covers 100 and 200, and like features are designated with the same reference numbers.

[0116] Multiple apertures 144 have been formed through the instrument panel cover 300. The apertures 144 in the embodiment of Figure 18 are similar to the apertures 144 shown in the grille 142 of Figure 12, albeit with different aperture sizes, number, and spacing. The apertures 144 can be formed through the substrate 102 in any suitable manner, depending upon the materials used to manufacture the substrate 102, and the intended aperture sizes and shapes. For example, the apertures can be drilled, melted, or punched through the substrate 102 after manufacture. Alternatively, the apertures can be formed in the skin (where present) 166 before manufacture of the substrate, and then the rest of each aperture can be completed in any suitable manner after manufacture of the substrate. The skilled person will understand that other methods and sequences of the forming the apertures in the substrate can be employed.

[0117] Figure 18 shows the location of the loudspeaker driver 1 16 relative to the apertures 144. Again, fastening means are omitted for clarity.

[0118] Although the compressible interface layer 114 has been described as being an injected foam, such as a polyurethane foam, it will be appreciated that the compressible interface layer 114 can alternatively take the form of a separately formed layer that is applied to the outer layer 104, skin 166 (where present), or structural layer 112. For example, the interface layer 114 can take the form of a moulded or otherwise formed layer of foam or other resilient material that is applied (e.g., adhered) to the structural layer 112. For example, the interface layer 114 can comprise one or more layers of a flexible and compressible knitted, spun, or otherwise formed material, fabric, or the like. Different layers can be combined to provide a desired compressibility response to the touch. 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.

Claims

CLAIMS1 . An instrument panel cover for a vehicle, the instrument panel cover comprising: a substrate, the substrate comprising: a loudspeaker recess or opening; and an airbag exit region; and an outer layer comprising a knitted fabric covering at least the loudspeaker recess or opening and the airbag exit region, the outer layer comprising a region of weakness overlying and / or adjacent to the airbag exit region, the region of weakness being configured to rupture in the event of airbag deployment.

2. The instrument panel cover of claim 1 , wherein the region of weakness extends parallel to a line of weakness in the warp or weft direction of the knitted fabric.

3. The instrument panel cover of claim 1 or 2, wherein the region of weakness comprises a portion that extends along part of a width of the instrument panel cover.

4. The instrument panel cover of any preceding claim, wherein the region of weakness comprises an incision cut at least partially into the knitted fabric.

5. The instrument panel cover of any preceding claim, wherein the region of weakness comprises one or more laser cuts.

6. The instrument panel cover of claim 5, wherein the region of weakness comprises a line of laser-cut through-holes.

7. The instrument panel cover of any one of claims 1 to 5, wherein the region of weakness is formed on a substrate side of the outer layer.

8. The instrument panel cover of any preceding claim, comprising a grille extending over the loudspeaker recess or opening, the grille supporting the outer layer where it covers the loudspeaker recess or opening.

9. The instrument panel cover of claim 8, wherein the outer layer is adhered to at least part of the substrate.

10. The instrument panel cover of claim 9, wherein the outer layer is adhered to the substrate with a contact adhesive.11 . The instrument panel cover of claim 8, wherein the grille comprises apertures, and the outer layer is adhered to the substrate and the grille, but there is no adhesive on the outer layer where it crosses the apertures.

12. The instrument panel cover of any preceding claim, wherein the substrate comprises: a structural layer; and a compressible interface layer disposed between the outer layer and the structural layer.

13. The instrument panel cover of claim 12, the interface layer comprising a material having physical characteristics that allow the interface layer to rupture in the event of airbag deployment.

14. An outer layer for use with the instrument panel cover of any preceding claim.

15. A vehicle comprising the instrument panel cover of any one of claims 1 to 13.

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