GB2633403A

GB2633403A - A moulded vehicle body structure

Info

Publication number: GB2633403A
Application number: GB2313826.6A
Authority: GB
Inventors: Szokalo Alicja; Beadle David
Original assignee: Jaguar Land Rover Ltd
Current assignee: Jaguar Land Rover Ltd
Priority date: 2023-09-11
Filing date: 2023-09-11
Publication date: 2025-03-12
Also published as: GB202313826D0

Abstract

A moulded vehicle body structure 100 is provided with a unitary body comprising a first region 120 and a second region 122, and a flexible joint 150 with a first end 152 and a second end 154. Regions 120, 122 are connected to joint 150 allowing relative movement between the regions. Application of a force, for example thermal expansion or contraction, the joint 150 changes a distance between its ends 150, 152. A third region 124 and a plurality of joints 150 may also be provided. One or both of regions 120, 122 may have a class A surface portion. An assembly, a vehicle and a mounting method are also provided.

Description

A MOULDED VEHICLE BODY STRUCTURE

TECHNICAL FIELD

The present disclosure relates to a moulded vehicle body structure. Aspects of the invention relate to a moulded vehicle body structure, an assembly for a vehicle, a vehicle and a method of mounting a moulded vehicle body structure to a vehicle.

BACKGROUND

It is known to provide moulded components for vehicles, for example, injection moulded polymer components such as parts of grills, visors, or support structures for other components. For relatively large components (approximately in the order of 100 mm to 2000 mm for a longest length along the component) any dimensional mismatch as a result of solidification shrinkage can cause issues with mounting the component on to the vehicle. This is due to the effect of shrinkage causing misalignment of mounting features which need to fit with complementary structures. Whilst relatively large components can still be employed where dimensional mismatch has occurred, they may need to be coaxed into position which can cause excess strain on the component and potentially causing breakage during assembly.

Traditionally, where such moulded components are relatively large, they are split up into two or more separately moulded components to reduce the magnitude of any solidification shrinkage that may occur during manufacture and post manufacture of the component. By splitting up components into smaller sized components it increases the amount of tooling required to manufacture which adds to build costs due to increased complexity.

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

SUMMARY OF THE INVENTION

Aspects and embodiments of the invention provide a moulded vehicle body structure, an assembly for a vehicle, a vehicle and a method of mounting a moulded vehicle body structure to a vehicle as claimed in the appended claims.

According to an aspect of the present invention there is provided a moulded vehicle body structure. The structure having: a unitary body comprising: a first region and a second region; a flexible joint having a first end and a second end; the first region is connected to the joint at the first end and the second region is connected to the joint at the second end enabling relative movement between the first region and the second region; and wherein application of a force acting on the joint changes a distance between the first end and the second end of the joint.

By enabling the distance between the ends of the joint to be changed, shrinkage (for example, from an injection moulding process) or thermal expansion can be compensated for. The flexible joints enable easier manipulation of the moulded vehicle body structure around mounting obstacles or the like.

Upon removal of the application of a force acting on the joint the distance may elastically return to an unactuated distance.

The ability to connect a number of normally separate regions together into a single moulded vehicle body structure enables relatively large components to be constructed (approximately in the order of 100 mm to 2000 mm for a longest length along the component). This arrangement would not be possible without the flexible joints, as shrinkage effects for large, moulded components become greater the larger the component.

Traditionally to counteract shrinkage effects mouldings may be manufactured by injection moulding using a lower viscosity polymer. Utilising lower viscosity polymers may however cause issues with final component strength as a decrease in viscosity may have consequences on a number of physical parameters of the final product which are governed by the material properties of the polymer material. The inventors of this invention have advantageously found a way to counteract the effect of shrinkage on moulded components without the need to alter materials properties of the moulded material.

By providing the joint and fixing two (or more) normally separate regions together this invention reduces component count enabling easier mounting of the moulded vehicle body structure as compared to two separate regions. Further, tooling requirements are decreased as the moulded component can be manufactured by one moulding operation rather than two separate moulding operations. This single moulding operation enables the production of more homogenous components as the same processing conditions will be applied to both regions during solidification as compared to a separate moulding operation for each region. Further, there is a reduced chance of colour mismatch and/or texture mismatch for surface finished structures of the invention as a single operation is undertaken to add the surface finish rather than two or more separate operations for each region of the structure.

Alternatively, a moulded vehicle body structure is provided, the structure having: a unitary body comprising: a first region and a second region; a flexible joint; the first region is connected to the joint and the second region is connected to the joint enabling relative movement between the first region and the second region; wherein application of a force acting on the joint changes a distance between the first region and the second region.

The alternative moulded vehicle body structure has the same advantages as the other moulded vehicle body structure.

Optionally, the relative movement between the first region and the second region is substantially planar and aligned with a substantially common plane of the first and second regions.

Relative substantially planar movement of the first and second regions enables the regions to be manipulated easily into place when undertaking various operations as discussed above. Moreover, as the relative movement is substantially planar it enables the structure to be mounted or fit or placed on a substantially common plane of the first and second regions. The substantially common plane may be a flat or curved surface, for example, where the moulded vehicle body structure is a component for a grill the structure can be manipulated to follow the curve of vehicle structure it may connect to.

The ability to manipulate the first and second ends apart between a minimum and maximum distance elastically and prior to plastic deformation means that the structure can be manipulated multiple times during different process steps on a number of process lines. Moreover, the ability to elastically deform the joints is useful for manipulation of the moulded vehicle body structure when it is being mounted as the ability to flex the moulded vehicle body structure into place without introducing more deformation reduces the chance of further misalignment.

Optionally, the first region comprises a first mounting feature and second region comprises a second mounting feature, wherein the joint is movable within a range of elastic deformation, said range being greater than or equal to a change in a lateral separation between the first and second mounting features associated with the moulded vehicle body structure transitioning between a first state and a second state.

The ability to manipulate the joint between a range of elastic deformation enables any change in lateral separation between a reference point on the moulded vehicle body structure and a mounting point to be compensated for after the moulded vehicle body structure has transitioned between a first and second state or at any point therebetween the two states. The change in lateral separation may be the result of manufacturing and/or environmental factors which may cause the increase or decrease in the lateral separation. By compensating for the change in lateral separation between the central point and the moulded vehicle body structure the joint enables easier manipulation of the moulded vehicle body structure.

The mounting feature may be provided by any part of the internal component which interacts with the external component, for example the protruding portions of the internal component could be the mounting features.

Wherein the external component is the component which faces the outside of the vehicle in use and the internal component is a component which is at least in part covered by the external component but may have externally facing protruding portions.

The reference point may be a centre point on the moulded vehicle structure or the centre of gravity of the moulded vehicle body structure, or it may be a central point along the longest axis of the moulded vehicle body structure, wherein the longest axis is defined by the two furthest points away from each other on the moulded vehicle body structure.

Optionally or additionally, where the moulded vehicle body structure comprises two or more mounting points on the first or second region, the change in the lateral separation is between a reference point on the moulded vehicle body structure and the mounting point that is greatest distance from the reference point when the moulded vehicle body structure is in the first state. In this manner the joint is able to compensate for larger changes in lateral separation, for example from solidification shrinkage where a greater change in lateral separation will be associated with mounting points further from the reference point than those closer to the reference point.

Optionally, the change in the lateral separation is associated with one or more of: solidification shrinkage of the moulded vehicle body structure, wherein the first state is before or during solidification of the moulded vehicle body structure and the second state is after solidification has completed; thermal expansion of the moulded vehicle body structure, wherein the first state is when the moulded vehicle body structure is at a first temperature and the second state is when the moulded vehicle body structure is at a maximum service temperature of the moulded vehicle body structure; and thermal contraction of the moulded vehicle body structure, wherein the first state when the moulded vehicle body structure is at the first temperature and the second state is when the moulded vehicle body structure is at a minimum service temperature of the moulded vehicle body structure.

The range of elastic deformation is greater than or equal to the associated solidification shrinkage means the joint is able to compensate for solidification shrinkage experienced by the moulded vehicle body structure during its manufacture. By enabling the flexible joints to flex and take up stress, it reduces stress or loading on the regions and/or any mounting points of said regions.

It will be appreciated that the thermal expansion or contraction will be experienced relative to the component or structure to which the moulded vehicle body structure is mounted. This may further be affected by a differential temperature between the moulded vehicle body structure and the component or structure to which it is mounted.

Additionally, the second state is after solidification has completed and the moulded vehicle body structure has cooled to the first temperature.

The first temperature may be the normal operating temperature of the vehicle and/or an ambient temperature of the workshop/manufacturing unit where the moulded vehicle body structure is manufactured or the vehicle is constructed or serviced. The first temperature may be 15 to 25°C, or 20°C.

The range of elastic deformation is greater than or equal to thermal expansion so that any thermal expansion of the moulded vehicle body structure in use up to the maximum service temperature of the component can be compensated for by the flexible joint. For example, where the moulded component is located adjacent to an internal combustion engine it may experience relatively high temperatures of 100 plus degrees C. In the thermally expanded state a compressive force is applied to the joint as the regions expand and therefore may push towards each other. By enabling the flexible joints to flex and take up stress, it reduces stress or loading on the regions and/or any mounting points of said regions.

The maximum service temperature may be 80-120°C or 100°C. The maximum temperature may alternatively or optionally be the glass transition temperature of a polymer or polymer blend the structure is manufactured from.

Similarly, the range of elastic deformation is greater than or equal to the thermal contraction so that any thermal contraction of the component can be compensated for by the flexible joint. For example, where the moulded component is in service in cold conditions, for example at -40 degrees C, and the vehicle is in an off state (and therefore not being heated by an ICE or other system) the moulded vehicle body structure will be in a thermally contracted state. In the thermally contracted state, a tensile force is applied to the joint as the first and/or second region will contract and cause the ends of the joint to pull away from each other. By enabling the flexible joints to flex and take up stress, it reduces stress or loading on the regions and/or any mounting points.

The minimum service temperature may be -40 degrees C. The range of elastic deformation may be 1.5 to 100 times greater than or equal to the lateral spacing associated with one or more of: solidification shrinkage, thermal expansion and thermal contraction.

Optionally or additionally, the change in the lateral separation is associated with thermal expansion of the moulded vehicle body structure, wherein the first state is when the moulded vehicle body structure is at a minimum temperature and the second state is when the moulded vehicle body structure is at a maximum service temperature of the moulded vehicle body structure.

Optionally or additionally, the change in the lateral separation is associated with thermal contraction of the moulded vehicle body structure, wherein the first state when the moulded vehicle body structure is at the maximum temperature and the second state is when the moulded vehicle body structure is at a minimum service temperature of the moulded vehicle body structure.

Optionally, the joint enables rotation of the first region relative to the second region within a displacement angle range.

The joints act similar hinges allowing the first and second region to pivot through an angle. This is particularly useful where the moulded vehicle body structure must be inserted through relatively small apertures on the production line and mounted in place.

Wherein the displacement angle range is -180 to 180 degrees, or -150 to 150 degrees, or -120 to 120 degrees or -90 degrees to 90 degrees, or -60 to 60 degrees, or -45 degrees to 45 degrees, or -30 to 30 degrees.

A maximum displacement angle may be at the bounds of the displacement angle range.

The joint comprises a minimum distance between the first end and the second end of the joint.

The minimum distance is the minimum distance between the first end and the second end of the joint that the moulded vehicle body structure can be manipulated to. The minimum distance may be when the first end and the second end of the joint are touching. The minimum distance may be the minimum distance between the first end and the second end of the joint before plastic deformation of the joint occurs.

Optionally, the joint comprises a first arm, a second arm and a central portion connecting the first arm to the second arm; and wherein the first end is disposed at the end of the first arm and the second end is disposed at the end of the second arm.

By providing a joint with arms this enables greater relative movement between the first and second regions connected to said arms.

Optionally, the joint is any one of: u-shaped, curved, s-shaped, oval, circular and sinusoidal. Advantageously, the joint can be provided in a variety of shapes to suit specific requirements of the component it forms a part of.

Optionally, the unitary body comprises: a plurality of said flexible joints; the first region being connected to each of said plurality of joints at the first end and the second region being connected to each of the plurality of joints at the second end enabling relative movement between the first region and the second region.

By providing a plurality of flexible joints the force is applied to more than a single joint reducing the stress level on the joints as compared to a higher stress on a single joint.

Optionally, the unitary body further comprises a third region; at least one further flexible joint having a first end and a second end; the third region is connected to the at least one further flexible joint at the first end thereof and the second region is connected to the at least one further flexible joint at the second end thereof, thereby enabling relative movement between the third region and the second region; and wherein application of a force acting on the at least one flexible joint changes a distance between the first end and the second end of the at least one further flexible joint.

The moulded vehicle body structure can comprise a third region connected to the second region via a second joint. The ability to connect a number of normally separate regions together into a single moulded vehicle body structure enables relatively large components to be constructed. This arrangement would not be possible without the flexible joints as shrinkage effects for large, moulded components become greater the larger the component. Traditionally to counteract shrinkage effects mouldings may be manufactured by injection moulding using a lower viscosity polymer, this however can cause issues with final component strength as a decrease in viscosity may have consequences on a number of physical parameters of the final product.

Optionally or additionally, the unitary body further comprises: a plurality of second flexible joints having a first end and a second end; the third region being connected to each of the plurality of second joints at the first end of each joint and the second region being connected to each of the plurality of second joints at the second end of each joint enabling relative movement between the third region and the second region; and wherein application of a force acting on each of the plurality of second joints changes a distance between the first end and the second end of each of the plurality of second joints.

Such an arrangement provides similar advantages as those previously described with the benefit of providing multiple joints being that forces are spread across all the joints rather than through a single joint.

Optionally the moulded vehicle body structure is any one of: a visor, at least a portion of a body panel, a grill, an exterior vehicle trim structure, an interior vehicle trim structure, a support structure, a cowl panel, at least a portion of an instrument panel. In such cases, the structure can be used on multiple different vehicle components.

Optionally, the moulded vehicle body structure has at least one class A surface portion on one or both of the first and second region. Optionally, where the moulded vehicle body structure comprises a third region the third region may optionally have at least one class A surface portion. The joints in such a structure aid in retaining the class A surface portion in place in use on the vehicle structure. This can aid in preventing water ingress.

Optionally, the moulded vehicle body structure comprises a polymer or polymer blend. The polymer may be any polymer suitable for injection moulding. The polymer may be a thermoplastic polymer. The thermoplastic polymer may be any one of: Acrylonitrile Butadiene Styrene (ABS), polycarbonate (PC), polyamaide (PA), polybutylene terephthalate (PBT), Acrylonitrile styrene acrylate (ASA), polypropylene (PP) (the PP may be a polymer blend e.g., a talc filler PP blend), a PC-ABS polymer blend, and/or Polymethyl methacrylate (PMMA).

The polymer may be a polymer blend comprising one or more of any of the previously described polymers and/or a second polymer of the previously described list and/or a filler material. The polymer may comprise at least in part a recycled polymer feedstock with the balance comprising virgin polymer feedstock and the normal impurities. The virgin polymer feedstock is any previously described polymer or polymer blend. The recycled polymer feedstock is any previously described polymer or polymer blend.

Optionally, the moulded vehicle body structure is manufactured using an injection moulding method. The injection moulding method may be a single-shot moulding method or a multi-shot moulding method. The injection moulding method may be a co-moulding method whereby the moulded vehicle body structure is moulded with a co-moulded component such that the co-moulded component forms part of the unitary body.

The co-moulded component may be a surface texture such as a weave (for example a carbon weave or polymer weave), additionally or optionally, the co-moulded component may be identification component for identifying the moulded vehicle body structure.

According to another aspect of the invention an assembly for a vehicle is described. The assembly comprising the moulded vehicle body structure according to any preceding claim and a complementary structure; the moulded vehicle body structure being mounted to the complementary structure; wherein the first region has at least one mounting point and is mounted to the complementary structure by the at least one mounting point; wherein the second region has at least one mounting point and is mounted to the complementary structure by the at least one mounting point; and wherein application of the force acting on the joint changes a mounting point distance between the first region at least one mounting point and the second region at least one mounting point.

The mounting points may be located at the mounting features as described above. The mounting points may be the mounting features.

The moulded vehicle body structure comprising the flexible joint enables easier mounting of the moulded vehicle body structure onto a complementary structure. The complementary structure may be a single component or a multi-part component of a vehicle. By applying a force to the moulded vehicle body structure, the distance between the first and second mounting points change, this enables the structure to be manipulated more easily and enable the structure to be easily mounted onto a complementary structure. This is advantageous over structures with no flexible joint which cannot be as easily manipulated into place. For example, where prior components, without a flexible joint, are mounted incorrectly any dimensional mismatch from a result of manufacturing defects or shrinkage may, when the structure is mounted via the mounting point(s), cause excess stress on the mounting point potentially leading to stress concentrations and potential early failure of the mounting point. Alternatively, it may lead to the misalignment of the moulded vehicle body structure and the complementary structure it connects to, this could lead to water ingress if the moulded vehicle body structure is an exterior vehicle part.

Optionally, the assembly comprises the moulded vehicle body structure of the embodiment where the structure has at least one class A surface portion on one or both of the first and second region; and wherein the class A surface portion aligns with an aperture of the complementary structure such that the class A surface portion is visible through the aperture.

The alignment of the exterior portion with the aperture in the present invention enables flush mounting of the exterior portion within the aperture. This reduces the likelihood of any gaps around the exterior portion from dimensional mismatch or misalignment which could lead to water ingress through the aperture-exterior portion connection. Preventing water ingress is particularly important for exterior facing moulded vehicle body structures of vehicles as often moulded vehicle body structures may have electronic sensing equipment mounted on an inner face. Electric sensing equipment, if exposed to water, can reduce useable lifespan.

According to a further aspect a vehicle is described. The vehicle comprising the moulded vehicle body structure according to the aspect describing the moulded vehicle body structure and/or the aspect describing the assembly. A vehicle comprising such a structure and/or assembly has the advantageous as described above.

Optionally, the vehicle may further comprise a complementary structure with an aperture. The complementary structure with an aperture enables a portion of the structure to be inserted therein.

According to a yet further aspect of the invention, a method of mounting a moulded vehicle body structure to a part of a vehicle is described. The method wherein the moulded vehicle body structure is required to be fitted by a partially obstructed mounting path, the method comprising the steps of: providing a moulded vehicle body structure for a vehicle, the structure having: a unitary body comprising: a first region and a second region; a flexible joint having a first end and a second end; the first region is connected to the joint at the first end and the second region is connected to the joint at the second end enabling relative movement between the first region and the second region; wherein application of a force acting on the joint changes a distance between the first end and the second end of the joint; applying a force to the joint to change the distance between the first end and the second end and enable the moulded vehicle body structure to be manoeuvred along the mounting path; and mount the moulded vehicle body structure to the part of the vehicle.

The mounting path may be at least partly occluded by a portion of the vehicle or a portion of a complementary structure that must be manoeuvred around or through or between or into engagement in order to mount the moulded vehicle body structure to the part of the vehicle. For example, the moulded vehicle body structure may be a component used on the inside of a bonnet (hood) adjacent an engine block and/or electric machine or other powertrain components. The bonnet rim, engine block, electric machine and powertrain components are all mounting obstacles in this case as the moulded vehicle body structure must be manipulated around them or through them as applicable. The flexible joints in the present invention enable the manipulation to be easily made without the need for multiple mounting operations of separated regions of separate moulded vehicle body structures. For example, the regions can be moved relative to each other to manipulate them along the mounting path. Where the mounting path is partly occluded by a portion of the complementary structure this may be due to openings in the complementary structure which obstruct the mounting path that, unless the moulded body structure is manipulated or deformed such that the structure aligns therein.

The part of the vehicle may be a body panel or a complementary structure such as that described above or any other suitable part of a vehicle. The part of the vehicle may be connected or disconnected from the rest of the vehicle when the structure is attached. For example, the structure could be mounted on a body panel or complementary structure then in turn the assembly being fixed to a vehicle or additional vehicle component.

The method may further comprise any additional features of the moulded vehicle body structure as described above.

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 vehicle according to an embodiment of the invention; Figure 2 shows a schematic rear view of a moulded vehicle body structure installed on the vehicle of Figure 1; Figure 3 shows the structure of Figure 2 in a front view; Figure 4 shows a close up view of a joint of Figure 2; Figure 5 shows a close up view of a joint of Figure 2 in an extended state; Figure 6 is a graph showing specific volume in relation to temperature of an amorphous polymer and semi-crystalline polymer; Figure 7 shows a moulded vehicle body structure according to an embodiment of the invention undergoing manufacture by a moulding process; Figure 8 shows a moulded vehicle body structure according to an embodiment of the invention undergoing a change in shape due to thermal contraction; and

DETAILED DESCRIPTION

A moulded vehicle body structure 100 in accordance with an embodiment of the present invention is described herein with reference to the accompanying Figures 1 to 8. As shown in Figure 1 the moulded vehicle body structure 100 is installed on a vehicle 1 on part of a body panel 10. For brevity, the moulded vehicle body structure 100 is also referred to as 'structure' 100.

The vehicle 1 is shown as a passenger vehicle, such as a car or sports utility vehicle (SUV). However, the vehicle 1 may be any type of vehicle known in the art, such as a commercial goods vehicle (e.g. a van), a heavy goods vehicle (e.g. a lorry or a truck). The application of the present disclosure is not limited to a particular vehicle type and may be utilised with any type of vehicle.

The body panel may have an aperture 12 for receiving an optional portion 110 of the structure 100 therethrough. In Figure 1-3 the portion 110 is a class A surface. Wherein the class A surface is a visible surface in use that may be felt and/or seen by the end user of the vehicle. Class A surfaces have good aesthetic quality of reflections. In use the class A surface 110 is aligned with and/or through the aperture 12 so that the class A surface 110 is visible through the aperture 12. In order to reduce the likelihood of water ingress but primarily to maintain the aesthetic consistency of the assembly 200 (gap and flush) into the vehicle 1 in use it is important that the fit between aperture 12 and class A surface 110 is maintained.

The particular implementation of the moulded vehicle body structure 100 and assembly 200 shown in Figure 1 is illustrative for the purpose of teaching the invention and is not intended to be limiting, the invention encompasses use as part of other arrangements for the vehicle 1 as will be apparent from careful reading of the disclosure. For example the moulded vehicle body structure 100 may be any one of: a visor, at least a portion of a body panel, a grill, an exterior vehicle trim structure, an interior vehicle trim structure, a support structure, a cowl panel, at least a portion of an instrument panel.

The structure 100 is described in further detail with the aid of Figures 2 to 5 which show the structure 100 installed on the body panel 10 of vehicle 1.

The structure 100 has a unitary body. The unitary body has two or more regions 120, 122, 124. In Figure 2, the regions 120, 122 and 124 are shown connected in series by joints 150 disposed between the first and second regions 120, 122 and the second and third regions 122, 124.

Each region 120, 122, 124 has one or more mounting features 130 disposed upon it. The mounting features 130 enable the structure 100 to be mounted onto a second component such as body panel 10. The body panel 10 may have complementary mounting features that engage with mounting features 130. Alternatively, or optionally, one or more of the regions 120, 122, 124 may not have a mounting structure 130. The mounting feature 130 may be the class A surface 110 which mounts to aperture 12 of the body panel 10 in use as is shown in Figures 1 and 3.

The joint 150 will now be described in more detail with the aid of Figures 4 and 5. The joint 150 enables the regions that are connected to it to be moved relative to each other such that any dimensional mismatch because of manufacturing defects like solidification shrinkage or thermal expansion/contraction can be compensated for when mounting the structure 100 and/or during normal use of the structure 100.

The first region 120 and the second region 122 are shown in close up in Figure 4. The first and second regions 120, 122 are connected by a flexible joint 150. The flexible joint 150 has a central portion 164 and two arms 160, 162 (first arm 160 and second arm 162). The first arm 160 is connected to the second arm 162 by the central portion 164. The first arm 160 connects to the first region at a first end 152 of the joint 150 and the second arm 162 connects to the second region 122 at a second end 154 of the joint 150 as is shown in Figure 4.

The joint 150 and the regions 120, 122 are unitary such that the joint 150 is continuous with the first and second regions 120, 122. As such, the joint 150 is substantially homogenous with the rest of the structure 100 and unitary body as a result materials properties are relatively consistent throughout the regions 120, 122, 124 and joint.

The flexible joint 150 enables the first and second regions 120, 122 to move relative to each other (when connected to a body panel 10 or when disconnected from a body panel 10), whilst at the same time retaining the connection between the three parts of the structure 100. The relative movement between the first and second regions 120, 122 is substantially planar and aligned with a substantially common plane of the first and second regions 120, 122. The common plane and therefore substantially planar movement may be curved, for example the inside face of a body panel 10 may be curved to enable an aerodynamic profile on the outside facing side of the body panel 10, as is the case with the visor-grill embodiment shown in Figure 1.

The joint 150 shown in Figure 4 and 5 is substantially u-shaped. However, the joint 150 may be any one of the following shapes: linear, curved, s-shaped, oval, semi-circular, circular and sinusoidal. Where, for example, the joint 150 is oval or circular the first arm may be a first chord of the oval or circle and the second arm may be a second chord of the oval or circle. The central portion 164 in such an embodiment may be the region connecting the first and second chords at a first end of both chords or the opposite end of both chords or the central portion may be the combination of both connecting regions.

The functionality of the joint 150 will now be described with the aid of Figures 2 to 8.

Figure 4 shows a zoomed in view of Figure 2 showing a joint 150 connecting the first and second regions 120, 122. The joint 150 is able to be manipulated elastically within a range of elastic deformation (that is, prior to any plastic deformation occurring) to enable the first and second regions 120, 122 to be manipulated in relation to each other. For example, the joint 150 shown in Figure 4 has a first distance Di between the first end 152 and second end 154, by application of a tensile force, F, on the first and second regions 120, 122 as is shown in Figure 5 the distance between the first end 152 and second end 154 is increased to D2. Conversely, if a compressive force is applied to the structure of Figure 4 on one or both of the first and second regions 120, 122 the distance would decrease to below Di. Conversely, if a torsional force is applied to the structure of Figure 4 on one or both of the first and second regions 120, 122 the distance would increase in relation to two laterally spaced or non-coaxial points on the joint 150 one being on the first end 152 and the second being on the second end 154.

The extent of the elastic deformation is to compensate for a change in lateral separation AL of mounting features 130 located on the first and second regions 120, 122. The lateral separation L1, L2 of the mounting features 130 changes as a result of various states in which the structure 100 finds itself in. The structure 100 has a lateral spacing L1 during a first state and a second lateral spacing L2 in a second state. The change in lateral separation is the difference between L1 and L2.

As a result, to compensate for the change in lateral separation AL, the range of elastic deformation is equal to or greater than the change in lateral separation AL associated with the structure 100 transitioning between the first state and second state. By compensating for the change in lateral separation AL the joint 150 reduces or negates the force which acts upon the one or more mounting features 130.

The extent in lateral separation AL is also able to account for any movement of the class A structures 110 located within aperture 12. This as a result maintains the class A surface 110 within the aperture 12 in use. Alternatively, or optionally the lateral separation may be measured between the furthest extremities of the class A structures 110, as these may be considered mounting points 130 (as the class A structures 110 are mounted into apertures 12 of the body panel 10 in use).

Various changes in lateral separation AL will now be discussed with the aid of Figure 6 to 8. Figures 7 to 8 show the effect of shape changes of simplified moulded vehicle body structures 100 comprising two regions 120, 122 joined by a single joint 150. This simplified structure 100 is described for the purpose of teaching the invention, in practice the structure 100 may comprise two or more 120, 122, 124 connected by one or more joints 150 in a variety of configurations.

The effect of the shape change when the moulded vehicle body structures 100 transition between a first and second state in Figures 7 to 8 have been exaggerated for the purpose of teaching the present disclosure. In each case, the extent of the change in lateral separation AL is compensated for by the actuation of the joint 150 as described above.

Moulded components undergo solidification shrinkage during manufacture. An example graph in Figure 6 shows the change in specific volume V (m3kg-1) of two idealised polymers during solidification for the same pressure. Curve 200 shows a specific volume V with temperature T (Kelvin) of an amorphous polymer and curve 210 shows the change in specific volume V with temperature T (Kelvin) of a semicrystalline polymer. T0 is the melting temperature of the polymer, Tg is the glass transition temperature, Td is the demoulding temperature (the temperature the injection moulded component is removed from a mould), Tatm is atmospheric temperature (the ambient temperature of the atmosphere or room, e.g. 18 to 22 C). The particular science regarding solidification shrinkage in polymeric materials is well known within the field of materials science, as such an in-depth explanation of the mechanism(s) for it is not required for the purposes of teaching the present invention.

As is well known, polymeric materials experience a reduction in size during solidification, this effect, whilst on the order of 0.1 to 5% can be pronounced on large components, for example a mould for a 1000 mm bar would be 10 mm shorter for a 1% solidification shrinkage.

As is known, polymeric materials undergo shrinkage from an initial volume at a first state, e.g. at -10 and a decreased volume at a second state Tan. This is indicated on Figure 7 which shows a mould 300 containing an injection moulded structure 302. The mould 300 may be any type of injection moulding mould. The injection moulding mould is complementary to the shape of the moulded vehicle body structure 100 such that solidified polymer injected into the mould 300 forms the injection moulded vehicle body structure 100.

As will be apparent, mould 300 is a single mould for the whole of structure 100. By undertaking the moulding in a single mould 300 (rather than two-or-more separate moulding operations) there is a decrease in tooling costs where separate moulds must be provided. Further, by moulding structure 100 in a single moulding step and not as separate units which are then joined to form a single structure there is a lower likelihood of mismatch in aesthetic qualities (e.g. surface finish or paint variability) as the structure 100 will undergo a single finishing operation rather than two-or-more separate finishing operations.

The solidification shrinkage AL with respect to the manufacturing step can be determined using one or more methods. For example, the solidification shrinkage may be determined via ASTM D955-21 "Standard Test Method of Measuring Shrinkage from Mould Dimensions of Thermoplastics". Alternatively, the solidification shrinkage AL may be determined from material specification data sheets for the specific material in question.

The solidification shrinkage may alternatively or optionally be determined as the change in lateral spacing AL before or during solidification of the moulded vehicle body structure and the second state is after solidification has completed. The change AL may therefore be determined as the difference in lateral spacing between the first and second mounting feature 130 in an idealised structure that fits 1-to-1 in a cold mould 300 and the lateral spacing of a final structure 304 that has been demoulded at Td and allowed to rest for a period of time at Tatm, e.g. 0 hours, 12 hours, 24 hours or 48 hours, after any demoulding shrinkage has occurred (the second state). By resting the structure 100 for a number of hours the affects of any post-shrinkage can be taking into consideration and/or increase in volume due to water absorption which can be seen in some polymers such as polyamides. The change in lateral spacing is indicated between the change in dimensions between cold mould moulding shape 310 (indicated by the hashed area) and the final structure 304.

Alternatively, the change AL may be determined as the difference in lateral spacing between the first and second complementary structures in the cold mould 300 used to form the mounting component 130 and the lateral spacing of a final structure 304 that has been demoulded at Td and allowed to rest for a period of time at Tatm, e.g. 0 hours, 12 hours, 24 hours or 48 hours, after any demoulding shrinkage has occurred (the second state). By resting the structure 100 for a number of hours the affects of any post-shrinkage can be taking into consideration and/or increase in volume due to water absorption which can be seen in some polymers such as polyamides. The change in lateral spacing is indicated between the change in dimensions between cold mould moulding shape 310 (indicated by the hashed area) and the final structure 304.

Alternatively, the change AL may be determined as the difference in lateral spacing between the first and second complementary structures in a hot mould 300 used to form the mounting component 130, the moulded vehicle body structure 100 being in a liquid or semi-liquid injection moulded state 302 and the lateral spacing of a final structure 304 that has been demoulded at Td and allowed to rest for a period of time at Tat., e.g 0 hours, 12 hours, 24 hours or 48 hours, after any demoulding shrinkage has occurred (the second state). By resting the structure 100 for a number of hours the affects of any post-shrinkage can be taking into consideration and/or increase in volume due to water absorption which can be seen in some polymers such as polyamides. The change in lateral spacing is indicated between the change in dimensions between injection moulded state 302 and the final structure 304.

The structure 100 may be manufactured by any suitable polymer. For example the structure 100 may be made from an amorphous thermoplastic or a semi-crystalline polymer. The polymer may be any one of: Acrylonitrile Butadiene Styrene (ABS), polycarbonate (PC), polyamaide (PA), polybutylene terephthalate (PBT), Acrylonitrile styrene acrylate (ASA), polypropylene (PP) (the PP may be a polymer blend e.g., a talc filler PP blend), a PC-ABS polymer blend, and/or Polymethyl methacrylate (PMMA). The polymer may be a polymer blend comprising one or more of any of the previously described polymers and/or a second polymer of the previously described list and/or a filler material. The polymer may comprise a recycled polymer feedstock, preferably also comprising a balance of virgin polymer feedstock and the normal impurities. The virgin polymer feedstock is any previously described polymer or polymer blend. The recycled polymer feedstock is any previously described polymer or polymer blend.

Thermal expansion and contraction and its effect on change in lateral spacing AL will be described with the aid of Fig. 8. For the purposes of explanation, the change in dimensions have been exaggerated to aid teaching the present disclosure.

Figure 8 shows the moulded vehicle body structure 100 at a first state at a first temperature Ti, structure 400 and a second thermally contracted structure 410 at a second temperature T2. Ti > T2. As is apparent from Fig. 6 polymeric materials undergo changes in specific volume with changes in temperature. At Ti the structure 400 has a first lateral spacing L1 which decreases to L2 as the structure 400 transitions between the first temperature Ti (first state) to the second temperature T2 (second state). The change in lateral spacing is indicated between the change in dimensions between structure 400 (indicated by the hashed area) and the structure at the second temperature 410.

On thermal expansion, the reverse is true. The structure 410 will thermally expand with increases in temperature from T2 to Ti causing the lateral spacing to increase from L2 to L1.

The first temperature may be the normal operating temperature of the vehicle and/or an ambient temperature Tatm of the workshop/manufacturing unit where the moulded vehicle body structure is manufactured or the vehicle is constructed or serviced. The first temperature may be 15 to 25 C, or 20 C. The first temperature Ti may be the maximum service temperature of the component, in other words the maximum temperature the structure 100 is likely to experience in use, for example if the structure is adjacent a heat source then the temperature may be 80-120°C or 100°C. Alternatively, or optionally, Ti, may be the glass transition temperature Tg of a polymer used to manufacture the structure 100. For example, where the polymer is ABS the Tg 105°C, for PP+TD12 the Tg is approximately -20°C, for ASA the Tg is 100°C, and for PC/ABS the T9 is approximately 100°C.

Above the glass transition temperature Tg polymers may begin to exhibit viscoelastic or rubbery behaviour as thermal energy of the environment is sufficient to enable molecular chains of the polymer to slide passed each other.

The second temperature may be any temperature below Ti for example T2 may equal Tatm where Ti > Tatnn.

Optionally, T2 may be the minimum service temperature of the structure 100. The minimum service structure may be -40 degrees C. The above description is under the assumption that the regions 120, 122 are held at a uniform temperature to describe the transition between the two states, whilst this is applicable for a number of scenarios where the structure 100 is uniformly heated and/or cooled in use (e.g. before start up of the vehicle 1), it may not be the case for all structures 100 due to their positioning on vehicle 1 in use. It may be that the first region 120 is located in an area adjacent a heat source (near or at Tg due to proximity to the engine block, engine exhaust, etc...) and the second region 122 is located in a comparatively cool area (Tatm as it is adjacent an air intake for example). As a result, there will be a temperature gradient across the structure with the first region 120 having a greater average temperature than the second region 122. As a result, the first region 120 will experience greater expansion than the second region 122. The flexing of the joint(s) 150 takes up any increase in volume of the first region 122 reducing or preventing misalignment of the second region 120 mounting points 130.

The same is true for the reverse, or where there is a greater thermal contraction in one of the first or second regions 120, 122 and a lesser or negligible thermal contraction in the other of the first or second regions 120, 122.

A method of mounting a moulded vehicle body structure 100 to a vehicle 1 is now described with the aid of Figure 1, 2 and 3. In order to mount the structure 100 to the body panel 10 the structure may be required to be translated through various apertures and or holes so that it fits within the vehicle 1. In this example the mounting path is partially obstructed by an obstacle. For example, where the structure 100 is a visor and is required to be body mounted to the front of vehicle 1 (as shown in Figure 1) the visor 100 must be translated through an aperture covered by the bonnet 2 into place around any other components which may already be within the vehicle 1.

In order to do this, the regions 120, 122, 124 are able to be moved relative to each other as discussed above. The regions 120, 122, 124 can then be manoeuvred around various obstacles which partially obstruct the mounting path. By application of a force on one of the regions 120, 122, 124 the joint(s) 150 are manipulated such that the distance between the first and second ends 152, 154 changes from D1 to D2. This enables the regions 120, 122, 124 to be moved into place to mount them via mounting features 130 onto the body panel 10.

Alternatively, within the context of this assembly process the structure 10 may be preassembled to the body panel 10 before the body panel 10 is fixed in turn to the vehicle 1. As such when the assembly 200 is manipulated into place in the vehicle 1 i.e., applying tensile, compressive or torsional forces to compensate for the front end being wide or narrow, the joint 150 changes to accommodate any change in shape to the assembly 200 so the parts 10, 100 do not break or separate.

Where the structure 100 has class A surfaces 110 this also enables the mounting of the class A surfaces 110 into the respective apertures 12 on the body panel 10.

The ability to manipulate the structure 100 into place means that components that are already installed in the vehicle 1, for example an engine block or electric machine do not need to be removed as may be the case were the visor made as single large component and not split up into regions 120, 122, 124 and joined by flexible joint(s) 150. Further, flexing a single large component in such a manner may introduce plastic deformation or cracks into the structure, this may be avoided by the novel and inventive structure 100 created by the inventors which has regions 120, 122, 124 that are able to be manipulated independently of each other whilst remaining connected together via joint(s) 150d.

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.

No. Feature 1 Vehicle 2 Bonnet/Engine Cover/Hood Body Panel 12 Aperture 100 Moulded Vehicle Body Structure Class A Surface First Region 122 Second Region 124 Third Region 130 Mounting Feature Joint 152 First End 154 Second End First Arm 162 Second Arm 164 Central Portion Assembly 300 Mould 302 Injection Moulded Structure 304 Final Structure 310 Cold Mould Moulding Shape 400 Structure At T1 410 Structure At T2 Distance D2 Distance F Force L1 Lateral Separation L2 Lateral Separation AL Change In Lateral Separation Temperature (Degrees Celsius) Ti First Temperature 12 Second Temperature Tatm Atmospheric Temperature Ta Demould Temperature Tg Glass Transition Temperature To Melting Temperature V Specific Volume (M3/Kg) Va Amorphous Polymer Specific Volume V0 Semicrystalline Polymer Specific Volume

Claims

CLAIMS1. A moulded vehicle body structure, the structure having: a unitary body comprising: a first region and a second region; a flexible joint having a first end and a second end; the first region is connected to the joint at the first end and the second region is connected to the joint at the second end enabling relative movement between the first region and the second region; wherein application of a force acting on the joint changes a distance between the first end and the second end of the joint.
2. A moulded vehicle body structure according to claim 1, wherein the relative movement between the first region and the second region is substantially planar and aligned with a substantially common plane of the first and second regions.
3. A moulded vehicle body structure according to claim 1 or 2, wherein first region comprises a first mounting feature and second region comprises a second mounting feature, wherein the joint is movable within a range of elastic deformation, said range being greater than or equal to a change in a lateral separation between the first and second mounting features associated with the moulded vehicle body structure transitioning between a first state and a second state.
4. A moulded vehicle body structure according to claim 3, wherein the change in the lateral separation (AL) is associated with one or more of: solidification shrinkage of the moulded vehicle body structure, wherein the first state is before or during solidification of the moulded vehicle body structure and the second state is after solidification has completed; thermal expansion of the moulded vehicle body structure, wherein the first state is when the moulded vehicle body structure is at a first temperature and the second state is when the moulded vehicle body structure is at a maximum service temperature of the moulded vehicle body structure; and thermal contraction of the moulded vehicle body structure, wherein the first state when the moulded vehicle body structure is at the first temperature and the second state is when the moulded vehicle body structure is at a minimum service temperature of the moulded vehicle body structure.
5. A moulded vehicle body structure according to any of claims 1 to 4, wherein the joint enables rotation of the first region relative to the second region within a displacement angle range.
6. A moulded vehicle body structure according to any of claims 1 to 5, wherein the joint comprises a first arm, a second arm and a central portion connecting the first arm to the second arm; and wherein the first end is disposed at the end of the first arm and the second end is disposed at the end of the second arm.
7. A moulded vehicle body structure according to any of claims 1 to 6, wherein the joint is any one of: u-shaped, curved, s-shaped, oval, circular and sinusoidal.
8. A moulded vehicle body structure according to any of claims 1 to 7, wherein the unitary body comprises: a plurality of said flexible joints; the first region being connected to each of said plurality ofjoints at the first end and the second region being connected to each of the plurality of joints at the second end enabling relative movement between the first region and the second region.
9. A moulded vehicle body structure according to any of claims 1 to 8, wherein the unitary body further comprises a third region; at least one further flexible joint having a first end and a second end; the third region is connected to the at least one further flexible joint at the first end thereof and the second region is connected to the at least one further flexible joint at the second end thereof, thereby enabling relative movement between the third region and the second region; and wherein application of a force acting on the at least one flexible joint changes a distance between the first end and the second end of the at least one further flexible joint.
10. A moulded vehicle body structure according to any of claims 1 to 9, wherein the moulded vehicle body structure has at least one class A surface portion on one or both of the first and second region.
11. An assembly for a vehicle comprising the moulded vehicle body structure according to any preceding claim and a complementary structure; the moulded vehicle body structure being mounted to the complementary structure wherein the first region has at least one mounting point and is mounted to the complementary structure by the at least one mounting point; wherein the second region has at least one mounting point and is mounted to the complementary structure by the at least one mounting point; and wherein application of the force acting on the joint changes a mounting point distance (AL) between the first region at least one mounting point and the second region at least one mounting point.
12. An assembly according to claim 11, wherein the assembly comprises the moulded vehicle body structure of claim 10; and wherein the class A surface portion aligns with an aperture of the complementary structure such that the class A surface portion is visible through the aperture.
13. A vehicle comprising the moulded vehicle body structure according to any of claims 1 to 10 and/or the assembly of either of claims 11 or 12.
14. A method of mounting a moulded vehicle body structure to a part of a vehicle wherein the moulded vehicle body structure is required to be fitted by a partially obstructed mounting path, the method comprising the steps of: providing a moulded vehicle body structure for a vehicle, the structure having: a unitary body comprising: a first region and a second region; a flexible joint having a first end and a second end; the first region is connected to the joint at the first end and the second region is connected to the joint at the second end enabling relative movement between the first region and the second region; wherein application of a force acting on the joint changes a distance between the first end and the second end of the joint; applying a force to the joint to change the distance between the first end and the second end and enable the moulded vehicle body structure to be manoeuvred along the mounting path; and mount the moulded vehicle body structure to the part of the vehicle.