NVH plug, vehicle sub-assembly, and vehicle

Abstract

A NVH (noise, vibration, harshness) plug 112 comprising: a first sealing element 114, a stem 118, a deformable second sealing element 120 extending radially outwards from the stem 118 and spaced from

Description

TECHNICAL FIELD The present disclosure relates to noise, vibration, and harshness (NVH) plugs. Aspects of the invention relate to an NVH plug, to a vehicle sub-assembly comprising such an NVH plug, and to a vehicle comprising such an NVH plug. BACKGROUND It is known to provide NVH plugs for vehicles. NVH plugs can improve noise, vibration and harshness characteristics when installed such vehicles. 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 an NVH plug, a vehicle sub-assembly, and a vehicle as claimed in the appended claims. According to an aspect of the present invention there is provided an NVH plug for sealing first and second coincident apertures in respective first and second spaced apart panels of a vehicle structure, the NVH plug being configured for installation via the first aperture, the NVH plug comprising: a first sealing element; a stem extending axially from the first sealing element; and a deformable second sealing element extending radially outwards from the stem and including at least a portion that is axially spaced from the first sealing element; wherein the NVH plug is configured such that, in use, the first sealing element seals the first aperture, and the second sealing element seals the second aperture. This may allow convenient sealing of coincident spaced-apart apertures and / or may allow the same NVH plug to be used with different aperture types and / or spacings. The second sealing element may comprise a radially extending flange. This may offer an effective seal while still allowing for convenient installation. The flange may be helical. This may allow the NVH seal to be screwed at least part of the way into its installed position. The flange may extend circumferentially around the stem. This may assist in providing a seal around the full circumference of an aperture into which the NVH seal is installed. The flange may have a tapered lead-in portion at an end distal from the first sealing element. This may help with alignment during installation. The flange may be configured to elastically deform in at least a radial direction during installation, thereby to seal between the flange and the second aperture. The NVH plug may comprise a plurality of the flanges spaced apart along the stem. This may offer additional flexibility regarding the range of aperture types and / or spacings with which the NVH plug can be used. The first sealing element may comprise a radially extending head portion. The head portion may comprise at least one drive formation allowing for, in use, torque to be applied to the NVH plug to rotate it as it is installed into the first and second apertures. This may improve the ability to rotate the NVH plug, whether manually or by machine, thereby assisting with installation. The drive formation may comprise a machine-drivable formation or may be configured to facilitate manual rotation of the NVH plug. The NVH plug may comprise at least one sealing formation disposed on or adjacent to an axial face of the head formation, the sealing formation being configured to deform during installation to form a seal with a surface of the first panel surrounding the first aperture. This may improve the seal formed at the first panel. The stem may be at least partly formed from a first material, and the second sealing element may be at least partly formed from a second material, wherein the first material is more elastic than the second material. The first material may provide stiffness and / or strength, while the second material may provide an improved seal. According to a further aspect of the present invention there is provided an NVH plug for sealing firstand second coincident apertures in respective first and second spaced apart panels of a vehicle structure, the NVH plug being configured for installation via the first aperture, the NVH plug comprising: a head portion; a stem extending axially from the head portion; and a deformable sealing element extending radially outwards from the stem and including at least a portion that is axially spaced from the head portion; wherein the NVH plug is configured such that, in use, the sealing element seals the second aperture. According to a further aspect of the present invention there is provided a vehicle sub-assembly comprising: first and second panels spaced apart panels having respective first and second coincident apertures; and the NVH plug of any preceding aspect, installed so as to seal the first and second apertures. According to an aspect of the present invention there is provided a vehicle comprising the NVH plug of any preceding aspect or the vehicle sub-assembly of any preceding aspect. 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 section through a vehicle structure in the form of a vehicle sub-assembly; Figure 2 shows a plan view of an aperture of the vehicle sub-assembly of Figure 1; Figure 3 shows a plan view of another aperture of the vehicle sub-assembly of Figure 1; Figure 4 shows a perspective view of an NVH plug, in accordance with an embodiment of the invention; Figure 5 shows a plan view of the aperture shown in Figure 3 with a portion of the NVH plug shown in Figure 4 represented using a circle with a broken perimeter; Figure 6 shows a perspective view of a further NVH plug, in accordance with an embodiment of the invention; Figure 7 shows a perspective view of a further NVH plug, in accordance with an embodiment of the invention; Figure 8 shows a perspective view of a vertical section through the NVH plug of Figure 4, installed in a vehicle sub-assembly; Figure 9 shows a perspective view of a vertical section through the NVH plug of Figures 4 and 8, taken at a 90° offset to the vertical section of Figure 8; Figure 10 shows a perspective view of a vertical section through the NVH plug of Figure 7, installed in a vehicle sub-assembly; Figure 11 shows a perspective view of a vertical section through the NVH plug of Figures 7 and 10, taken at a 90° offset to the vertical section of Figure 10; Figure 12 shows a perspective view of a further NVH plug, in accordance with an embodiment of the invention; Figure 13 shows a close-up view of a head portion of the NVH plug of Figure 12; Figure 14 shows a perspective view of a section through a further NVH plug, in accordance with an embodiment of the invention, installed in a vehicle sub-assembly; Figure 15 shows a perspective view of a section through a further NVH plug, in accordance with an embodiment of the invention, installed in a vehicle sub-assembly; Figure 16 shows a vertical section through an outer region of a head portion of an NVH plug, in accordance with an embodiment of the invention; Figure 17 shows the outer region of the head portion of Figure 16, with the NVH plug installed in a vehicle sub-assembly; Figure 18 shows a side elevation of a further NVH plug, in accordance with an embodiment of the invention; Figure 19 shows a vertical section through the NVH plug of Figure 18; and Figure 20 shows a perspective view of a vehicle in accordance with an embodiment of the invention. DETAILED DESCRIPTION Referring to Figure 1, there is shown a section through a vehicle sub-assembly 100. The NVH seals described herein can also be used with other vehicle structures. The vehicle sub-assembly 100 comprises a first panel 102 and a second panel 104. Each panel may comprise one or more layers. The first and second panels 102, 104 are spaced apart, as represented by double-ended arrow 106. The first panel 102 has a first aperture 108. The second panel 104 has a second aperture 110. The first and second apertures 108,110 are coincident apertures. In this example, the first and second apertures 108, 110 are coincident in that they are aligned with each other. Apertures may be aligned where one aperture at least partly overlies the other aperture. Apertures may be coincident where a line that is perpendicularto one of the panels, and that passes through an aperture in that panel, also passes through the aperture in the other panel. In this example, the first and second panels 102, 104 are planar. At least one of the first and second panels 102,104 may be non-planar in other examples. For example, at least one of the first and second panels 102,104, may be curved, optionally such that the first and second panels are equidistant to each other over at least part of their surface areas. In this example, the first and second panels 102, 104 each have a single aperture 108, 110. At least one of the first and second panels 102, 104 may have more than one aperture 108, 110 in other examples. Referring to Figure 2, there is shown an aperture. In this specific example, the aperture corresponds to the first aperture 108 and is therefore referred to in Figure 2 using reference sign 108. In this specific example, the aperture 108 is circular. In this specific example, the aperture 108 has a diameter of about 13 millimetres (mm), but it will be appreciated that embodiments of the invention may be configured for use with apertures having other diameters. Referring to Figure 3, there is shown a further aperture. In this specific example, the further aperture corresponds to the second aperture 110 and is therefore referred to in Figure 3 using reference sign 110. In this specific example, the aperture 110 is in the form of a slot. The slot may be used as a locator for an assistor while fixing an instrument panel (IP) assembly during a body in white (BIW) manufacturing stage. In this specific example, the aperture 110 takes the form of an obround having a width of about 13 mm and a length of about 19 mm. An example implementation comprises a first panel 102 with a round aperture 108 and a second panel 104 with a slot aperture 110. The first panel 102 has a thickness of 1.8 mm. The second panel 104 has a thickness of 4.1 mm. The first and second panels 102, 104 are spaced apart by 16.8 mm. An alternative implementation also comprises a first panel 102 with a round aperture 108 and a second panel 104 with a slot aperture 110. The first panel 102 has a thickness of 3.5 mm. The second panel 104 has a thickness of 4.1 mm. The first and second panels 102, 104 are spaced apart by 14.2 mm. Other implementations include round apertures in both the first and second panels, obround apertures in both the first and second panels, any combination of round and obround apertures in the first and second panels, and any other combination of aperture shapes (including oval apertures and rounded apertures, for example). Stricter NVH requirements, for example for electric vehicle platforms, may increase the importance of reducing airborne noise transmission. Existing solutions may not be satisfactory, for example in terms of ease of installation and / or the effectiveness of NVH reduction. An existing NVH plug might plug the round aperture 108 effectively but might not reduce sound transmission through the slot aperture 110 effectively or at all. There may be slightly different panel spacings within one vehicle, and / or similar vehicles with different panel spacings may be produced within the same factory or even on the same production line. Similarly, even considering only plugging the first aperture, different aperture types may require different plugs. It may be inconvenient to maintain a stockpile of different NVH plugs for different applications. One challenge is therefore to provide an NVH plug that can be used with different panel spacings. Another challenge is to cover both round and obround apertures (or apertures having other shapes, such as square, rectangular, triangular, or other regular or irregular shapes). Each panel can be formed from a single metal layer. Alternatively, each panel can be formed from one or more metal layers optionally laminated or otherwise reinforced with a further layer formed from metal or another material. An additional challenge is therefore to reach and plug an aperture spaced apart (by 14-16 mm, in the described embodiments) from a mounting surface where there is no other access to that aperture and, therefore, where an individual rubber plug cannot readily be used to plug that aperture due to access difficulties. A further challenge is to provide an NVH plug that can be readily installed. For example, an NVH plug that is difficult to push through the apertures 108,110 may be difficult to install. A further challenge is to achieve improved, and optionally target, NVH characteristics. In general terms, an NVH plug comprises a stem. The NVH plug comprises sealing elements extending from the stem. The sealing elements may be configured such that the NVH plug can pass through a first, optionally round, aperture in a first panel during installation, and also cover another, optionally obround, aperture in a second panel spaced from the first panel. Referring to Figure 4, there is shown an NVH plug 112. The NVH plug 112 is for sealing firstand second coincident apertures 108,110 in respective first and second spaced-apart panels 102,104 of a vehicle sub-assembly 100. The NVH plug 112 is configured for installation via the first aperture 108. In other words, in this example, the NVH plug 112 Is configured for installation in the vehicle sub-assembly 100 by inserting the NVH plug 112 through the first aperture 108. The NVH plug 112 comprises a first sealing element 114. The first sealing element 114 comprises a radially-extending head portion 116. In this example, the head portion 116 is disc-shaped. An underside axial face 128 of the head portion 116 is configured to engage with an outer / upper surface of the first panel 102 immediately surrounding the first aperture 108 when the NVH plug 112 is installed, as described in more detail below. The NVH plug 112 comprises a stem 118 that extends from the first sealing element 114. In particular, the stem 118 extends axially from the first sealing element 114. The thickness, configuration, and construction material(s) of the stem 118 may be selected to provide a target level of rigidity. Higher rigidity of the stem 118 may facilitate installation of the NVH plug 112 in the vehicle sub-assembly 100 by stiffening the NVH plug 112 both axially and torsionally . In contrast, reduced stem thickness may facilitate bending of the NVH plug 112. While increased bending may offer improved post-installation compliance, increased bending may also make installation of the NVH plug 112 more difficult, as the NVH plug 112 may be insufficiently stiff to allow it to easily be pushed through the first aperture 108. The skilled person will choose an appropriate combination of materials, configuration, and dimensions to satisfy any required rigidity requirements, including axial and / or torsional rigidity requirements. The NVH plug 112 comprises a deformable second sealing element 120. The deformability of the second sealing element 120 facilitates pushing of the second sealing element 120 through the first aperture 108 and into the second aperture 110. The second sealing element 120 may be resiliently deformable. This may enable the second sealing element 120 to readily pass through the first aperture 108 and then resiliently seal the second aperture 110, without needing additional manual manipulation of the second sealing element 120 after the second sealing element 120 has passed into the second aperture 110. The second sealing element 120 extends radially outwards from the stem 118. In this context, “radially” means having a radial component. For example, in the embodiment of Figure 4, the second sealing element 120 extends radially, but also axially in a direction towards the first sealing element 114. The second sealing element 120 includes at least a portion that is axially spaced from the first sealing element 114. In this example, all portions of the second sealing element 120 are axially spaced from the first sealing element 114. The second sealing element 120 comprises a flange 122. The flange 122 is a radially- and axially-extending flange 122. The flange 122 extends circumferentially around the stem 118. In this specific example, the second sealing element 120 is bowl-shaped. The second sealing element 120 may also be considered to be in the form of a skirt, umbrella, or inverted cone. The flange 122 has a tapered lead-in portion 124. The tapered lead-in portion 124 of the NVH plug 112 is at an end distal from the first sealing element 114. The second sealing element 120 and the tapered lead-in portion 124 enable the NVH plug 112 to pass through the first aperture 108 and into the second aperture 110. The flange 122 is configured to elastically deform in at least a radial direction during installation. This seals between the flange 122 and the second aperture 110. The NVH plug 112 comprises at least one retaining formation 126. In this specific example, the retaining formation 126 is disposed adjacent to, but spaced apart from, the axial face 128 of the head portion 116. The retaining formation 126 is configured to deform radially inwards during installation, to allow it to pass through the first aperture 108. Once through the first aperture 108, the retaining formation 126 springs radially outwards into (or at least towards) its original configuration, which holds the NVH plug 112 in place and impedes its removal. In this specific example, the retaining formation 126 has a plurality of notches 130. In this specific example, each notch 130 is U-shaped. In this specific example, each notch 130 extends radially outwards along the retaining formation 126, starting adjacent to the stem 118. In this specific example, the retaining formation 126 has four such notches 130. In this specific example, the notches 130 are equally spaced circumferentially around the retaining formation 126. Figure 4 includes a dotted line 142, indicating a shape of the left hand side of the NVH plug 112 (excluding the retaining formation 126, for clarity) in vertical section when installed, such as in the panels 102, 104. A solid line 144 indicates the shape of the left-hand side of the second sealing element 120 in vertical section, prior to installation of the NVH plug 112. The difference between line 144 and the corresponding portion of line 142 shows the radial compression and distortion of the second sealing element 114 as a result of installing the NVH plug 112. This compression and distortion of the second sealing element 114 helps seal the second aperture 110. The deformability and resilience of the second sealing element 120 may be selected as a function of construction materials) and configuration. For example, and as shown in the example of Figure 4, the second sealing element 120 can be significantly thinner in axial cross section than the first sealing element 114, thereby achieving the required deformability and resilience while maintaining sufficient rigidity in the rest of the NVH plug 112. The NVH plug 112 may be made at least partly from ethylene propylene diene terpolymer (EPDM). In a specific example, the NVH plug 112 is made at least partly from EPDM 70 Shore A. The NVH plug 112 is configured such that, in use, the first sealing element 114 seals the first aperture 108, and the second sealing element 120 seals the second aperture 110. In this example, the stem 118 is non-tapering from the axial face 128 of the head portion 116 to where the second sealing element 120 joins the stem 118. The NVH plug 112 may be a push-fit NVH plug 112, which may be installable by pushing the NVH plug 112 into the first and second apertures 108, 110, either by hand or with the assistance of a suitable installation tool. Figure 5 is a schematic plan view showing how the retaining formation 126 (the radially outer edge of which is indicated by a dashed line for clarity) can still retain the NVH plug 112 in position by engaging the underside surface of the first panel 102, even if the first aperture 108 is an obround aperture (e.g., similar to the second aperture 110 of Figure 3) having a long axis that exceeds the diameter of the retaining formation 126. It will also be appreciated that the retaining formation 126 is sized and configured such that it will operate to retain the NVH plug 112 in place, even if the retaining formation 126 ends up positioned offset laterally relative to the first aperture 108, or along the length of the first aperture 108. Referring to Figure 6, there is shown a further NVH plug 112. In this example, the flange 122 of the NVH plug 112 is helical. In this specific example, the helical flange 122 comprises approximately 2.5 turns around the stem 118. The helical design enables the NVH plug 112 to be driven like a screw into the correct final position. An NVH plug 112 with a helical flange is therefore configured to be rotated into position rather than being pushed into position, although in certain applications, it may be possible to push the NVH plug 112 partly or wholly into position. It will be appreciated that, in other embodiments, the helical flange can include a different number of turns, and can use a different pitch, to suit particular implementation requirements. The helical flange 122 may enable the NVH plug 112 to provide a relatively secure seal for NVH purposes, by deforming as it is screwed at least partly through the second aperture 110. The resilience of the helical flange 122 ensures that the second aperture 110 is wholly or largely sealed. The head portion 116 of the NVH plug 112 comprises at least one drive formation 132. In this specific example, the head portion 116 of the NVH plug 112 has a single drive formation 132. The drive formation 132 allows for, in use, torque to be applied to rotate the NVH plug 112 as the NVH plug 112 is installed into the first and second apertures 108, 110. In this specific example, the drive formation 132 is a machine-drivable formation 132. In this specific example, the machine-drivable formation 132 is a 12 mm hex slot of 3.7 mm depth. The machine-drivable formation 132 may facilitate quicker installation, for example using a manual or powered rotary drive tool. In this example, the stem 118 of the NVH plug 112 comprises a first portion that tapers inwardly from the axial face 128 of the head portion 116 to the start of a second portion that comprises the helical flange 122. The wider part of the first portion adjacent to the head portion 116 provides space for the drive formation 132, while the taper assists in centring of the NVH plug 112 relative to the first aperture 108 as the NVH plug 112 is driven into its installed position. In this example, the stem 118 is nontapering in the second stem portion. Referring to Figure 7, there is shown another NVH plug 112. The head portion 116 of the NVH plug 112 comprises at least one drive formation 132. In this example, the drive formation 132 is configured to facilitate manual rotation of the NVH plug 112 as the NVH plug 112 is installed into the first and second apertures 108,110. In this specific example, the drive formation 132 comprises plurality of protrusions 136. In this specific example, each protrusion 136 is on an upper axial face 138 of the head portion 116. In this specific example, the head portion 116 has four such protrusions 136. In this specific example, the four protrusions 136 are equally spaced radially around the head portion 116. The spaces between each of the protrusions 136 are large enough to accommodate at least part of the tip of a human digit. This facilitates manual rotation of the NVH plug 112. Optionally, drive formations configured for manual interaction may be configured such that they can also be driven by a suitable rotary drive tool. For example, the NVH plug 112 of Figure 7 may be driven by a tool having formations that fit into one or more of the recesses between adjacent protrusions 136. The end of the helical flange 122 furthest from the head portion 116 defines a further tapered lead-in portion in the form of a ramped portion 146. The ramped portion 146 helps to align the helical flange 122 with the first and second apertures 108,110 as it initially engages each of them during installation. The ramped portion 146 also reduces the amount of torque required to initiate rotation of the NVH plug as the helical flange begins to be screwed into the respective first and second apertures 108,110. Although not shown due to the viewing angle, the NVH plug 112 of Figure 6 has a similar lead-in portion 146. The NVH plugs 112 shown in Figures 4, 6 and 7 may all have a similar height as each other, as measured from the underside of the head portion 116 to the distal end of the NVH plugs where the tapered lead-in portion 124 terminates. Referring to Figures 8 and 9, there is shown a vehicle sub-assembly 100. Figures 8 and 9 show the same NVH plug 112 installed into the same apertures, but show vertical sections taken at a 90° offset from each other. The vehicle sub-assembly 100 comprises first and second spaced apart panels 102, 104 having respective first and second coincident apertures 108,110. In this example, the first aperture 108 is circular (e.g., similar to the first aperture 108 of Figure 2) and the second aperture 104 takes the form of an obround slot (e.g., similar to the second aperture 110 of Figure 3). An NVH plug 112, corresponding with the NVH plug 112 shown in Figure 4, is installed so as to seal the first and second apertures 108,110. To install the NVH plug 112, the tapered lead-in portion 124 and second sealing element 120 are pushed through the first aperture 108. The second sealing element 120 deforms as it passes through the first aperture 108. The second sealing element 120 then reverts to its original form once it has passed through the first aperture 108. The NVH plug 112 is then pushed further into the vehicle sub-assembly 100, causing the tapered lead-in portion 124 and second sealing element 120 to be pushed into the second aperture 110. The second sealing element 120 deforms as it is compressed radially inwards by the inner edges of the second aperture 110. Due to the resilient nature of the second sealing element 120, the outer surface of the second sealing element 120 is urged radially outwards into sealing contact with the inner edge of the second aperture 110. Due to the obround shape of the second aperture 110, the second sealing element 120 is deformed by different amounts at different circumferential positions. For example, Figure 8 shows edges of the second sealing element 120 in contact with the edges at the opposite ends of the obround second aperture 110. Because those ends are a relatively long way from each other, the periphery of the second sealing element 120 is deformed (in the radially inwards direction) only slightly in these regions once the NVH seal 112 is installed. In contrast, Figure 9 shows the edges of the second sealing element 120 in contact with opposite edges on the long sides of the obround second aperture 110. Because those opposite edges are closer to each other than the edges at the opposite ends of the second aperture 110, the periphery of the second sealing element 120 is deformed relatively more in these regions than in the regions shown in Figure 8, once the NVH seal 112 is installed. This also causes the edges of the second sealing element 120 in Figure 9 to be pushed up higher, relative to the second aperture 110, than the edges of the second sealing element 120 in Figure 8. Additionally, the retaining formation 126 has been pushed into the first aperture 108, causing the retaining formation 126 to deform as the retaining formation 126 passes through the first aperture 108, and then revert to Its original form once the retaining formation 126 has passed through the first aperture 108. As described above, the retaining formation 126 retains the NVH plug 112 in the installed position through contact with an underside of the first panel 102. The abutment of the first sealing element 114 with the upper surface of the first panel 102 prevents the NVH plug 112 from being pushed further into the vehicle sub-assembly 100, and forms a seal around the first aperture 108 as a result of the axial face 128 engaging the adjacent upper surface of the first panel 102. Referring to Figures 10 and 11, there is shown another vehicle sub-assembly 100. In this specific example, the NVH plug 112 corresponds to the NVH plug 112 described above with reference to Figure 7. To install the NVH plug 112, the tapered lead-in portion 124 is pushed into the first aperture 108, and manually rotated such that the helical flange 122 is screwed into the first aperture 108. After approximately 2.5 turns of the NVH plug 112, the helical flange 122 passes through the first aperture 108. The NVH plug 112 is then pushed further into the vehicle sub-assembly 100. When the helical flange 122 reaches the second aperture 110, the tapered lead-in portion 124 is pushed into the second aperture 110. The NVH plug 112 is manually rotated such that the helical flange 122 is screwed into the second aperture 110. As the NVH plug 112 is rotated, it draws the first sealing element 114 downwards until its underside axial face 128 abuts the first panel 102 adjacent to the first aperture 108. Further rotation of the NVH plug 112 may cause some further deformation of the helical flange 122, which further improve the seal between the second sealing element 120 and the second aperture 110. Eventually, the interaction of the first sealing element 114 with the first panel 102, and of the second sealing element 120 with the second aperture 110, prevents the NVH plug 112 from being rotated further. In Figures 10 and 11, the first sealing element 114 forms a seal around the first aperture 108 as a result of the axial face 128 engaging the adjacent upper surface of the first panel 102. Referring to Figures 12 and 13, there is shown another NVH plug 112. As best shown in Figure 13, the drive formation 132 takes the form of a hex slot 132. In this example, the diameter of the hex slot 132 is reduced from 12 mm to 10 mm. In this example, the depth of the hex slot is increased from 3.7 mm to 5 mm. The additional slot depth facilitates retention of a hex key in the hex slot and reduces the chance of slipping or camming out. The NVH plug 112 of Figures 12 and 13 is installed in generally the same manner as the NVH plug 112 as described in relation to Figures 10 and 11. The operation of the helical flange 122 means that the NVH seal of Figures 6 to 11 does not include a separate retaining formation, such as retaining formation 126. A retaining formation, such as retaining formation 126, can be optionally be included on any NVH seal 112 that uses a helical flange 122. Similar, the retaining formation 126 can optionally be omitted from any of the embodiments described herein, especially if the materials and configuration of the NVH plug mean that it will retain itself in the installed position without such a retaining formation. Referring to Figures 18 and 19, there is shown another NVH plug 112. The NVH plug 112 of Figures 18 and 19 is similar to the NVH plug 112 shown in Figures 12 and 13. One difference is that the NVH plug 112 of Figures 18 and 19 has a longer ramped portion 146, which allows for improved centring and a more gradual engagement of the flange 122 with an aperture as it is screwed into position during installation. Another difference is that the flange 122 of the NVH plug 112 of Figures 18 and 19 has a greater number of turns than the embodiment shown in Figures 12 and 13. Yet another difference with the embodiment of Figures 18 and 19 is that the flange 122 is canted upwardly in cross-section. That is, the radially outer edge of the flange 122 terminates at a higher (in the orientation of Figure 13) point than the radially inner edge of the flange 122 where it joins the stem 118. The canting encourages the flange to deform by folding upwards (relative to the orientation of Figure 13) during installation, which may allow for easier and / or more consistent installation. The flange 122 ofthe embodiment of Figures 12 and 13 also includes an upward curve, in cross-section. This results in a “cupped” shape that is similar, at least at a given circumferential position, to the cupped shape ofthe (non-helical) flanges of Figures 4 and 14. This profile may further improve centring, and / or allow for easier and / or more consistent installation. While the canting of flange 122 in Figures 18 and 19 extends along substantially its entire length, in other embodiments the canting extends along only a portion ofthe flange’s length. The stem 118 ofthe embodiment of Figures 12 and 13 has a cylindrical profile adjacent to the head portion 116, leading into a tapering section, and then a narrower cylindrical portion leading to the tapered lead-in portion 124. About half ofthe upper length ofthe flange 122 extends along the tapering section, with the remainder ofthe flange extending along the narrower cylindrical portion. The radial width ofthe flange 122 reduces as it extends along the tapering section towards the head portion 116. This makes the flange 122 increasingly resistant to deformation as it is screwed into an aperture, while the increasing diameter ofthe tapered portion helps wedge the deformed flange into contact with the inner edge ofthe aperture. This may improve the seal and / or help resist overtightening. Referring to Figure 14, there is shown another NVH plug 112, installed in a vehicle sub-assembly 100. The NVH plug 112 of Figure 14 corresponds generally to the NVH plug 112 shown in Figure 4. However, the NVH plug 112 shown in Figure 14 comprises a plurality ofthe flanges 122 spaced apart along the stem 118. In this example, the flanges 122 are spaced equally in an axial direction along the stem 118. In this example, the flanges 122 are cup-shaped. In this specific example, there are four flanges 122. However, there may be a different number of flanges 122 in other examples. In this specific example, the flanges 122 are the same as each other. However, in other examples, some or all ofthe flanges 122 are different from each other. The NVH plug 112 of Figure 14 is installed by pushing it through the first aperture 108 and into the second aperture 110. As shown in Figure 14, when installed, the NVH seal 112 is held in place by the engagement ofthe two lowermost flanges 122 with the second panel 104 in the vicinity ofthe second aperture 110, and the engagement of the axial face 128 with the upper surface of the first panel 102. The size, positions, and spacing ofthe flanges 122 can be selected to ensure that the NVH seal of Figure 14 is retained appropriately when the flanges 122 interact with first and second panels 102,104 of known spacing. Referring to Figure 15, there is shown a further NVH plug 112. In this case, the second sealing element 120 comprises first and second flanges 122 that are spaced apart from each other near the lower end of the stem 118. The first and second flanges 122 are annular, rather than cup-shaped, and extend radially from the stem 118. The NVH plug is installed by pushing it into the first and second apertures 108,110, until the lowermost of the flanges 122 passes through the second aperture 110. At this point, the lowermost flange 122 pops back to its original shape, retaining the NVH plug 112 in the installed position. While the embodiments described above are all formed from a single material (such as EPDM, for example), the NVH plug can be manufactured from two or more different materials. For example, the stem can be formed from a relatively rigid material, and the first and second sealing elements can be formed from a more resilient material. Optionally, the head of the NVH seal can be formed from a relatively rigid material, optionally in one piece with the stem. The second sealing element can be overmoulded onto, or otherwise attached or mounted to, the stem. Using a relatively rigid material for at least some of the stem may contribute to increased strength and rigidity of the NVH seal as a whole. Using a more resilient material for either or both of the sealing elements allows for greater compliance, and hence may provide an improved seal. Optionally, the first sealing element comprises a lip, ridge, or other sealing formation on the first sealing element’s underside. For example, Figure 16 shows a vertical section through the head portion 116 of an NVH seal 112. A lip 134 extends downwardly and outwardly from the outer edge of the axial face 128, and extends circumferentially around the head portion 116. As shown in Figure 17, when the lip 134 engages the upper surface of the first panel 102, it deforms by bending outwardly, providing an improved seal. Alternatively, the lip, ridge or other sealing formation is formed from a resilient material, which compresses during installation, again providing an improved seal. Optionally, the sealing formation can be formed from a different material to the head portion 116. For example, the sealing formation can be formed from a resilient material and the head portion can be formed from a relatively rigid material. The lip, ridge, or other sealing formation may take any other suitable form. The lip, ridge, or other sealing formation may also extend around the head portion at any suitable distance from the stem. Referring to Figure 17, there is shown a vehicle 140. The vehicle 140 can take the form of a road vehicle, which is a vehicle that is capable of being driven on a road. Non-limiting examples of such vehicles include cars, SUVs, trucks, vans, and the like. Such vehicles can also have offroad uses. For example, some SUVs and trucks are designed with occasional or even frequent offroad use in mind. The vehicle 140 may comprise an NVH plug 112 as described herein. The vehicle 140 may comprise a vehicle sub-assembly 100 as described herein. It will be appreciated that various changes and modifications can be made to the present invention 5 without departing from the scope of the present application.

Claims

1. An NVH plug for sealing first and second coincident apertures in respective first and second spaced apart panels of a vehicle structure, the NVH plug being configured for installation via the first aperture, the NVH plug comprising:a first sealing element;a stem extending axially from the first sealing element; anda deformable second sealing element extending radially outwards from the stem and including at least a portion that is axially spaced from the first sealing element;wherein the NVH plug is configured such that, in use, the first sealing element seals the first aperture, and the second sealing element seals the second aperture.

2. The NVH plug of claim 1, wherein the second sealing element comprises a radially extending flange.

3. The NVH plug of claim 2, wherein the flange is helical.

4. The NVH plug of claim 2, wherein the flange extends circumferentially around the stem.

5. The NVH plug of any one of claims 2 to 4, wherein the flange has a tapered lead-in portion atan end distal from the first sealing element.

6. The NVH plug of any one of claims 2 to 5, wherein the flange is configured to elastically deform in at least a radial direction during installation, thereby to seal between the flange and the second aperture.

7. The NVH plug of any one of claims 2 to 6, comprising a plurality of the flanges spaced apart along the stem.

8. The NVH plug of any preceding claim, wherein the first sealing element comprises a radially extending head portion.

9. The NVH plug of claim 8, wherein the head portion comprises at least one drive formation allowing for, in use, torque to be applied to the NVH plug to rotate it as it is installed into the first and second apertures.

10. The NVH plug of claim 9, wherein the drive formation comprises a machine-drivable formation.

11. The NVH plug of claim 9, wherein the drive formation is configured to facilitate manual rotationof the NVH plug.

12. The N VH plug of any one of claims 8 to 11, comprising at least one sealing formation disposed on or adjacent to an axial face of the head formation, the sealing formation being configured to deform during installation to form a seal with a surface of the first panel surrounding the first aperture.5 13. The NVH plug of any preceding claim, wherein the stem is at least partly formed from a firstmaterial, and the second sealing element is at least partly formed from a second material, wherein the first material is more elastic than the second material.

14. A vehicle sub-assembly comprising:10 first and second spaced apart panels having respective first and second coincident apertures;andthe NVH plug of any preceding claim, installed so as to seal the first and second apertures.

15. A vehicle comprising the NVH plug of any one of claims 1 to 13, or the vehicle sub-assembly 15 of claim 14.

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