GB2580901A

GB2580901A - Composite structure and method of forming a composite structure

Info

Publication number: GB2580901A
Application number: GB1900954.7A
Authority: GB
Inventors: Lakic Alex; Sicard Frederic
Original assignee: Jaguar Land Rover Ltd
Current assignee: Jaguar Land Rover Ltd
Priority date: 2019-01-23
Filing date: 2019-01-23
Publication date: 2020-08-05
Anticipated expiration: 2039-01-23
Also published as: DE112020000494T5; GB201900954D0; WO2020152240A1; GB2580901B

Abstract

Method of forming vehicle component 160 comprising: introducing into mould tool 142,143 at least one reinforcing tie 110 comprising at least one continuous reinforcing fibre portion (112, fig.3) coupled and secured to the mould tool at a plurality of spaced apart locations of the mould tool; and introducing moulding material 158 to the mould tool whereby the moulding material is moulded by the mould tool and the tie is at least partially encapsulated by the moulding material. A motor vehicle component 160 comprising plastics material 158 and at least one reinforcing tie 110 spanning a length within the component, the tie comprising at least one continuous reinforcing fibre portion (112, fig.3), wherein the tie is at least partially encapsulated by the plastics material. The tie may be provided with two or more retention portions (pegs 114A,114B, fig.1), coupling the fibre portion to the mould tool comprising coupling the retention portions to corresponding spaced apart retention portion locating features of the mould tool. The reinforcing fibre portion may comprise a substantially continuous fibre element and/or a plurality of fibre elements.

Description

COMPOSITE STRUCTURE AND METHOD OF FORMING A COMPOSITE STRUCTURE

TECHNICAL FIELD

The present disclosure relates to a composite structure, in particular but not exclusively a reinforced composite component, and a method of formation thereof. Aspects of the invention relate to at least a composite structure, a component, a vehicle component, a vehicle and to a method.

BACKGROUND

It is known to produce vehicle components from metals, such as steel, aluminium and aluminium alloy materials. Composite materials provide an opportunity to fabricate vehicle components that are of reduced weight. However, in some applications composite structures are found to have insufficient strength, for example insufficient tensile strength, in one or more directions.

Fibre reinforced plastic (FRP) components offer large potential mass savings compared to their metallic equivalents, particularly when the orthotropic (directional) nature of fibre reinforcement is capitalised on.

In the case of sheet-like components subject in use to defined principal loading directions, it is known to arrange patches of unidirectional fabric (composed of organised aligned long fibres) within a collection of overlaid sheets. The structure is arranged such that, when compacted and cured, the relatively stiff, heavy fibres are aligned only in the directions most required to provide the required strength. A lightweight plastic or resin matrix is employed to bind the whole and transmit stresses. This arrangement is significantly lighter than corresponding metallic stampings.

In the case of components that need not be sheet-like, but can be permitted instead to adopt complex 3D shapes (such as components formed by casting), a plastic or resin matrix material pre-imbued with short reinforcing fibres is typically employed. The reinforcing fibres are sufficiently short to permit the flow of a moulding dose into a desired complex shape in a mould tool. Such components lack the strength of corresponding components formed by casting of metals and are therefore of limited utility in structural components subject to substantial stresses.

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

SUMMARY OF THE INVENTION

Aspects and embodiments of the invention provide a method, a component and a vehicle as claimed in the appended claims In one aspect of the invention for which protection is sought there is provided a method of forming a vehicle component comprising: introducing at least one reinforcing tie into a mould tool, the tie comprising at least one continuous reinforcing fibre portion; coupling the at least one continuous reinforcing fibre portion, secured between locations, to the mould tool at a plurality of spaced apart locations of the mould tool; and introducing moulding material to the mould tool whereby the moulding material is moulded by the mould tool and the tie is at least partially encapsulated by the moulding material.

Embodiments of the invention have the advantage that a reinforcing element in the form of a tie comprising a continuous reinforcing fibre portion may be incorporated into a structure in a position determined by the locations at which the reinforcing fibre is coupled to the mould. Directional enhancements in tensile strength due to the presence of the tie may thereby be imparted to the structure.

Optionally, the tie is provided with at least two retention portions at axially spaced locations of the tie, coupling the at least one continuous reinforcing fibre portion to the mould tool comprising coupling the retention portions to the mould tool at corresponding spaced apart retention portion locating features of the mould tool.

Thus, the tie may be coupled to the mould tool (which may also be referred to as a 'mould') in a convenient manner. Furthermore, variations in tie position between respective structures formed by a given mould tool may be reduced due to provision of the mould tool with locating features for the tie retention portions. Thus, a risk that an operator fails to locate the tie in a given position of the mould tool may be reduced. Furthermore, a risk that the position of the tie changes when moulding material is introduced into the mould tool such that the tie is not provided in the desired location is reduced.

Optionally, the retention portions may comprise datum features for accurately holding -e component in a jig during the activity of joining the component to another component.

Optionally, introducing the at least one continuous reinforcing fibre portion comprises introducing the at least one reinforcing fibre portion when the mould tool is in an open condition and subsequently closing the mould tool whereby the mould tool is caused to assume a closed condition.

Optionally, introducing moulding material to the mould tool comprises introducing moulding material to the mould tool whilst the mould tool is in the open condition.

Thus, moulding material may be placed in the mould tool whilst the mould tool is open, allowing an operator, or a robot or other automated equipment, to place moulding material at one or more required locations of the tool. The moulding material may for example be in the form of viscous pieces of moulding material that substantially retain the shape in which an operator, or a robot or other automated equipment, places the pieces in the mould tool until the mould tool is closed. That is, the moulding material may experience little or substantially no change in shape under its own weight following introduction into the mould tool, prior to closing the tool. In some arrangements the moulding material may be of sufficiently low viscosity to experience at least some change in shape under its own weight following introduction into the mould tool, prior to closing the tool.

Optionally, introducing moulding material to the mould tool comprises introducing moulding material to the mould tool whilst the mould tool is in the closed condition.

Thus, moulding material may be introduced to the mould tool before and/or after closing the mould tool. In some embodiments moulding material in the form or liquid or molten moulding material may be injected into the mould tool in an injection moulding operation.

Optionally, the mould tool is provided with locating features for retaining the retaining portions of the tie in a substantially fixed position when moulding material is moulded by the mould tool and the tie is at least partially encapsulated by the moulding material.

The method may comprise allowing the moulding material to cure.

The method may comprise providing the fibre portion whereby the fibre portion comprises at least one substantially continuous fibre element.

The method may comprise providing the fibre portion whereby the fibre portion comprises a plurality of fibre elements joined to form the continuous fibre portion.

Optionally, a length of at least two of the fibre elements is less than a length of the path of the continuous fibre portion between the spaced apart locations of the mould tooth to which the fibre portion is secured.

Thus, the at least two fibre elements must be coupled to one another in order to form the continuous fibre portion, since individually their length is less than that required to span the distance between the locations at which the tie is secured to the mould tool.

Optionally, the moulding material comprises lengths of a material in the form of fibre elements embedded in a plastic moulding compound that deforms plastically to conform to an internal cavity of the mould tool defining a shape of the component to be moulded when the mould tool is closed.

By plastic compound is meant a compound that exhibits plasticity. Optionally the compound may comprise a plastics material following curing.

Optionally, the fibre elements comprised by the moulding material are of a length less than 10mm. For example, the fibre elements comprised by the moulding material may be less than 0.8mm. In some embodiments, the fibre elements comprised by the moulding material may longer than 0.3mm, and in some embodiments may be between 0.3mm and 0.8mm.

Optionally, the fibre elements comprised by the moulding material are of a length in the range from 3mm to 50mm, optionally in the range from 5mm to 40mm, optionally in the range from 10mm to 30mm, optionally in the range from 15mm to 25mm.

Optionally, a fibre element comprises one selected from amongst a carbon fibre element and a glass fibre element.

It is to be understood that by carbon fibre element or glass fibre element is meant a single element or strand of carbon fibre material.

In a further aspect of the invention there is provided a method of assembling a motor vehicle comprising: forming a component according to any preceding claim; and incorporating the component into the motor vehicle in a process of motor vehicle assembly.

In an aspect of the invention there is provided a motor vehicle component comprising a plastics material and at least one reinforcing tie spanning a length within the component, the tie comprising at least one continuous reinforcing fibre portion, wherein the tie is at least partially encapsulated by the plastics material.

Optionally, the fibre portion is substantially surrounded along substantially the whole length thereof by said plastics material.

Optionally, the tie comprises first and second retention portions coupled to the reinforcing fibre portion at opposite ends thereof.

The retention portions may each comprise a peg member arranged to be pegged to an internal wall of a mould tool.

Optionally, the first and second retention portions each have at least a portion exposed at a free surface of the component.

Optionally, the at least a portion of the first and second retention portions exposed at a free surface of the component comprises a tool coupling portion arranged to couple the retention portions to a wall of a mould tool.

Optionally, at least one of the retention portions comprises joining means for joining the component to another component.

Optionally, the joining means comprises at least one selected from amongst a threaded shaft, an externally threaded shaft, a shaft with an internal bore and a shaft with a threaded internal bore.

In one aspect of the invention for which protection is sought there is provided a vehicle comprising a component according to another 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.

For the avoidance of doubt, it is to be understood that features described with respect to one aspect of the invention may be included within any other aspect of the invention, alone or in appropriate combination with one or more other features.

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 is a schematic illustration of a tie according to an embodiment of the present invention; FIGURE 2 illustrates schematically a process of installation of a peg member into a mould tool, showing (a) the arrangement of a tie and mould tool prior to coupling of one peg member of the tie to the mould tool, (b) the tie and mould tool after coupling one peg member of the tie to the tool, and (c) the tie shown in (a) and (b) after coupling peg members at opposite ends of the tie to the mould tool; FIGURE 3 is a cross-sectional view of substantially the whole of the mould tool lower portion of FIG. 2 showing the tie installed therein; FIGURE 4 is a schematic illustration of a series of six steps in the forming of a component in a method according to an embodiment of the present invention; FIGURE 5 is a cross-sectional view of a mould tool corresponding to the view of FIG. 3 following (a) loading of charges of moulding compound into the mould tool and (b) following closure of the mould tool and wetting of the mould tool and tie by the moulding compound; FIGURE 6 is a schematic illustration of a portion of a component according to an embodiment of the present invention formed to include a tie according to a further embodiment of the present invention; FIGURE 7 is a schematic illustration of a tie according to a further embodiment of the present invention wherein a fibre portion of the tie comprises a plurality of carbon fibres; FIGURE 8 is a schematic illustration of a fibre portion of a tie according to a further embodiment of the present invention wherein the fibre portion of the tie comprises a plurality of carbon fibres impregnated with moulding compound resin and embedded in moulding compound; FIGURE 9 is a schematic illustration of a vehicle according to an embodiment of the present invention in which a component formed according to an embodiment of the present invention has been installed; FIGURE 10 is a schematic illustration of an assembly of components according to an embodiment of the present invention; and FIGURE 11 is a schematic illustration of an assembly of components according to a further embodiment of the present invention.

DETAILED DESCRIPTION

As noted above, the problem exists that the specific stiffness of known (discontinuous) fibre reinforced plastics moulding materials is insufficient to justify using them to replace motor vehicle structural components currently formed by metal casting. In order to provide the necessary cost-justifying lightweighting and stiffness, one aspect of the present invention teaches to embed a 'tie' in the form of a length of one or more fibres within the component.

One or more ties may be provided within the component each aligned in a direction corresponding to that along which the component is subject to one or more forces so as to enhance a stiffness and/or strength of the component in that direction. Thus the ties may be provided in locations in which they may resist applied loading to which the component is expected to be subject.

A method of forming a component according to an embodiment of the present invention will now be described.

FIG. 1 is a schematic illustration of a tie 110 suitable for embedding in a component formed by moulding of a plastics material. The tie 110 has a reinforcing fibre portion 112 comprising a single, substantially continuous, reinforcing fibre or 'fibre element'. In the present embodiment the reinforcing fibre element is a carbon fibre element. In some alternative embodiments the fibre portion 112 may comprise a plurality of reinforcing fibre elements. A fibre portion 112 comprising more than one fibre element may be referred to as a 'tow'. It is to be understood that the fibre elements comprised by a tow may be untwisted, i.e. not twisted together. In some alternative arrangements, the fibre elements of a fibre portion may be twisted together. In some embodiments the fibre elements may be fashioned into a rope. Fashioning into a robe may provide a fibre portion 112 having a consistent, reproducible cross-section that facilitates processing. In some embodiments the fibre elements may be fashioned into tapes.

A fibre element other than carbon fibre elements may be useful in some embodiments, such as a glass fibre or fibre element formed from any other suitable material. Fibre elements of different respective materials may be employed in some embodiments, for example in the same fibre portion of a tie or in respective different ties.

In some embodiments, the fibre portion 112 may comprise fibre elements that do not run continuously from one end of the tie 110 to the other. Thus, the fibre portion 112 may comprise fibre elements that are shorter than the fibre portion 112, but which are bonded together to form the continuous fibre portion 112. The bonding between fibre elements may be provided by resin and/or moulding compound/moulding material during fabrication of the ties 110 before insertion into a mould tool for moulding, as described below.

The fibre portion 112 is coupled at opposite ends thereof to a respective retention portion in the form of a peg member 114A, 1148. In the present embodiment the peg members 114A, 1148 are formed from a plastics material although other materials may be useful in some alternative embodiments such as a metal, for example a metal alloy. The fibre portion 112 is coupled to the peg members 114A, 11413 by embedding of a free end of the fibre portion 112 in a respective peg member 114A, 1148. The purpose of the peg members 114A, 1148 is to enable the tie 110 to be positioned and retained in a desired position within a mould tool and coupled to the tool to constrain movement of the tie 110. The tie 110 is arranged to be capable of being coupled to a mould tool such that the act of moulding the component does not disturb the position of the tie 110 within the tool.

FIG. 2(a) shows the tie 110 of FIG. 1 prior to coupling of the tie 110 to a mould tool 140 in which a component may be moulded. In the arrangement of FIG. 2(a) the mould tool 140 has a lower portion 142 and a corresponding upper portion 143. When the lower and upper portions 142, 143 are brought into mutual contact, a cavity 110C is defined by the portions 142, 143, the cavity 110C defining the shape of the pail to be moulded by the tool 140.

Each peg member 114A, 114B is arranged to be insertable into a corresponding locating feature in the form of a peg mount recess 144 provided in an internal surface of the mould tool 140. In the embodiment of FIG. 2(a) the peg mount recess 144 is provided in the lower portion 142 of the mould tool 140.

FIG. 2(b) shows the mould tool 140 with a first peg member 114A attached to the lower portion 142 of the mould tool 140 by insertion of a shaft portion 114AS of the peg member 114A into the peg mount recess until a head portion 114AH sits in contact with an interior surface of the mould tool lower portion 142.

FIG. 2(c) shows the first peg member 114A and fibre portion 112 following coupling of the second peg member 114B to the mould tool 140 -as may be seen from FIG. 2(c) the fibre portion 112 has become taught, and in the present example substantially straight.

FIG. 3 is a cross-sectional view of substantially the whole of the mould tool lower portion 142 showing the tie 110 installed therein. As shown in FIG. 3, the shaft portions 114AH, 114BH of each peg member 114A, 114B are substantially parallel to one another in order to facilitate removal of the peg members 114A, 114B from the recesses 144 once the peg members 114A, 1 14B have become embedded in the component following moulding.

FIG. 4 shows a series of six steps in the forming of a component 160 (FIG. 4(f)) in a method according to an embodiment of the present invention.

As step S101 (FIG. 4(a)) a charge of moulding compound (or 'moulding material') 158 is introduced into the mould tool 140 and placed on the lower mould tool portion 142. In the present embodiment the moulding compound 158 comprises, for example, a two-part epoxy resin compound impregnated with relatively short fibres. Alternatively, the moulding component 158 may comprise, for example, vinylester. In the present embodiment the fibres are in the size range from around 3 to around 50mm in length although other sizes may be useful. The size may be selected so that the fibre length is not too long to prevent flow of moulding compound 158 within the mould tool 140 but sufficiently long to permit an enhancement in one or more mechanical properties of the material, for example an enhancement in strength of the material. In some embodiments, a fibre length of 25mm is found to be useful.

In the present embodiment the moulding compound is a pre-mixed two-part epoxy resin compound with hardener. Provided it is maintained below a certain temperature (in the present embodiment around 50C) the polymerisation reaction that results in hardening ('setting' or 'curing') of the compound is relatively slow and permits handling of the moulding compound 158 including loading into the mould tool 142, 143. However, once the mould tool 140 is heated above a certain temperature at the curing stage (step S109 below) the moulding compound 158 'sets' and hardens.

At step S103 (FIG. 4(b)) the upper mould tool portion 143 is lowered towards the lower portion 142.

At step S105 (FIG. 4(c)) the upper mould tool portion 143 contacts the moulding compound 158 and begins to compress the moulding compound 158. The pressure exerted by the upper mould tool portion 143 on the moulding compound 158 in turn causes the moulding compound to exert pressure on the peg members 114A, 114B to retain them within their respective peg mount recess 144. The moulding compound 158 also begins to flow within the mould tool 140, wetting the surfaces defining the mould tool cavity 110C.

At step S107 (FIG. 4(d)) the upper mould tool portion 143 continues to be lowered until the mould tool 142, 143 is closed and the cavity 110C between the lower and upper mould tool portions 142, 143 is substantially filled with moulding compound 158.

At step S109 (FIG. 4(e)) the mould tool 140 is held in the closed condition as shown whilst the moulding compound 158 is permitted to cure sufficiently to allow the resulting moulded component 160 (comprising the moulding compound 158 and the one or more ties 110 embedded within it) to be removed from the tool 140 at step S111 (FIG. 4(f)). In the present example, the mould tool 140 is heated to a temperature in the range from around 130C to around 200C in order to cause curing of the moulding compound 158 at a sufficiently high rate.

Once the component 160 has been removed from the mould tool 140, the shafts 114AS, 114BS of the peg elements 114A, 114B may be removed by cutting, for example by means of a blade, so that the peg elements 114A, 114B do not have shafts 114AS, 114BS or portions of their shafts 114AS, 114BS projecting from the component 160. In some embodiments the peg elements 114A, 114B may be retained as part of the component. For example, the peg elements 114A, 114B may be arranged to permit coupling of the component to another vehicle component. In some embodiments, the peg elements 114A, 114B may be provided with additional means for coupling to another component in the form of an external screw thread, an internal bore, an internal threaded bore, a diametrical hole therethrough or any other suitable additional means. Thus in some embodiments the peg elements 114A, 114B may be provided with an internal bore, optionally a threaded internal bore, in addition to their shaft portion 114AS, 114BS. In some embodiments the shaft portions 114AS, 114BS may be threaded, externally and/or internally.

In some embodiments one or more shaft portions 114AS, 114BS may be arranged to facilitate accurate positioning of a component in order to facilitate joining to another component, resulting in a dimensionally accurate assembly. For example, one or more shaft portions 114AS, 114BS may facilitate accurate positioning of one component relative to a jig, for example by insertion of a shaft member 114AS, 114BS into a recess or hole in the jig, or accurate positioning of a component comprising the peg element 114A, 114B relative to another component. For example the shaft portion 114AS, 114BS of one component may be placed in a corresponding aperture or recess in another component to which the component is to be joined, whereby the components are held in a substantially fixed relative orientation, whilst joining of the components such as welding or other joining method takes place.

It is to be understood that one or more other elements may be placed in the mould tool 140 so as to become embedded within the component 160 during the moulding process conducted over steps S101 to S109. The one or more other elements may, by way of example only, include one or more elements having a threaded bore to permit the component 160 to be screwed or otherwise attached to another component. Other means for attachment of a component 160 to another component may be embedded, such as an element with a non threaded bore, an element with a shaft protruding outwardly from the component 160, and so forth. The shaft may be threaded or provided with other means for attaching the shaft to the other component. In some embodiments the one or more other elements may be provided for the purpose of locating the component 160 in a predetermined position relative to a jig and/or another component whilst joining of the component to the other component takes place. Other arrangements may be useful in some embodiments.

FIG. 5(a) is a further cross-sectional view of the mould tool 140 showing both the first and second peg members 114A, 114B coupled thereto. FIG. 5(a) shows the tool 140 in the open condition with charges of moulding compound 158 therein. As can be seen in FIG. 5(a) the charges of moulding compound 158 have been placed over the first and second peg members 114A, 114B in this example. In some other examples the charges of moulding compound 158 may not be placed directly over one or both peg members 114A, 1148 prior to commencing closing of the mould tool 114A, 1148.

FIG. 5(b) is a cross-sectional view of the mould tool 142, 143 following closure thereof. As can be seen, the moulding compound 158 has flowed within the tool 140 to envelop the tie 110 and substantially fill the cavity 110C defined by the tool 140.

It is to be understood that a density of a component formed as described above but without the presence of any tie 110 may be in the range from around 1.4g to 1.5g per cubic centimetre whilst the Young's Modulus may be around 30-40 GPa. This is in contrast to a corresponding aluminium component which may have a density of around 2.6g per cubic centimetre and a Young's Modulus of around 69-70 GPa. By including one or more ties 110 in order to enhance component stiffness, the Young's Modulus may be increased to values of around 130 GPa in the region of the tie and along the direction of the tie 110, exceeding those of a corresponding component formed from aluminium. The inclusion of one or more ties 110 in a component formed from a plastics material as described above can thus be seen to provide a substantial increase in stiffness, permitting a significant reduction in weight (or 'lightweighting') of a component with relatively sparing use of the relatively expensive materials from which the tie 110 is fashioned.

FIG. 6 illustrates a portion of a component 260 formed to include a tie 210 according to a further embodiment of the present invention. Like features of the tie 210 of the embodiment of FIG. 6 to those of the tie 110 of the embodiment of FIG. 1 are shown with like reference signs incremented by 100.

In the embodiment of FIG. 6, the tie 210 has a pair of substantially identical peg members (only one of which is shown) having a different shape to those of the embodiment of FIG. 1. The peg member 214A illustrated in FIG. 6 differs from the peg members 114A, 114B of the embodiment of FIG. 1 in that the shaft portion 214S has a substantially spherically-shaped key portion 214K at one end thereof, and a head portion 214H (corresponding to the head portion 114H of the embodiment of FIG. 1) provided at a location spaced apart from the key portion 214K along a length of the shaft portion 214S.

In a similar manner to the head portion 114H of the embodiment of FIG. 1, the head portion 214H of the embodiment of FIG. 6 is arranged to abut a surface of the lower portion 242 of the mould tool 240 when a portion of the shaft portion 2145 at the end opposite the key portion 214K is inserted into the peg member recess 244 formed in the lower portion 242 of the mould tool 240.

The key portion 214K of the peg member 214A is arranged to retain the peg member 214A embedded in-situ in the moulding material 258 following curing thereof so that the peg member 214A does not work loose and become detached from the component 260 following release of the component 260 from the mould tool 240. It is to be understood that adhesion of a peg member 114A, 214A to moulding material 158, 258 to retain the peg member in a component 160, 260 may not be a trivial task. Therefore, forming the peg member 214A to have a shape that can interlock mechanically with the moulding material 258 may be advantageous in preventing loosening or detachment of a peg member from a formed component. It is to be understood that such shapeform interlocking may provide a convenient solution to this problem. It is to be understood that shapeform interlocking employing a shape other than the substantially spherical ball shape of the embodiment of FIG. 6 may be useful in some embodiments.

Although the example given is of a spherical key portion 214K, the significant geometric characteristic of this embodiment is the re-entrant nature of the section of the key portion 214K that results in an interlocking arrangement of peg 214 and moulding compound 258. The interlocking arrangement resists pull-out of the peg 214 in the direction of the axis of the shaft portion 214AS, 214BS in the absence of friction or bonding between the peg 114 and cured moulding compound 158.

It is to be understood that the use of a curved shape without substantially sharp corners may be advantageous in promoting flow of moulding compound 258 during the moulding process in order to avoid the formation of voids within the moulding compound 258. The tie 210 of the embodiment of FIG. 6 has a fibre portion 212 having a single carbon fibre as in the embodiment of FIG. 1. However as noted above the fibre portion 212 may be formed to have more than one fibre in some embodiments. Furthermore, the one or more fibres may be formed from any other suitable material in some embodiments, such as a glass.

In a further embodiment of the present invention, a tie 310 may be provided as illustrated in FIG. 7. Like features of the tie 310 of the embodiment of FIG. 7 to those of the tie 110 of the embodiment of FIG. 1 are shown with like reference signs incremented by 200.

The tie 310 of the embodiment of FIG. 7 has a fibre portion 213 formed from a plurality of carbon fibres. Furthermore, the fibres of the fibre portion 312 are also pre-coated with a resin component of the two-part moulding compound 358 prior to the moulding operation. Thus, the tie 310 may be considered to be 'pre-impregnated' (or 'pre-wetted') with resin. This feature that wetting of the fibres of the fibre portion 312 with resin prior to the moulding operation in the mould tool 142, 143 has the advantage of reducing (or eliminating) the problem that wetting of the entire length of all the (one or more) fibres of a given fibre portion 312 does not occur during a moulding operation in which upper and lower portions 142, 242, 143, 243 of a mould tool 140, 240 are brought together to cause flow of moulding compound 158, 258. Thus, adhesion of the fibre portion 312 to moulding compound may be enhanced by pre-wetting with resin.

It is to be understood that the pre-wetting resin, being the resin used to pre-impregnate (pre-wet) the one or more fibres of the fibre portion 312 need not be the same resin used in the moulding compound 358 employed in the component moulding process, as long as there is sufficient chemical bonding and compatibility between the two resins for the purpose of component formation.

In addition to pre-wetting the fibre or fibres of the fibre portion 312 with resin, the resin-wetted fibres can be partially cured ('part-cured') prior to subsequent operations. For example, part-curing may be performed prior to coupling the fibre portion 312 to one or more peg members 314A, 314B, or after coupling to one or more peg members 314 but prior to moulding. Optionally, part-curing may take place during the process by which the peg members are coupled to the fibre portions 312).

It is This part-curing could make the ties less tacky to handle, less likely to lose / re-distribute resin in storage and handling, make the multi-fibre cross-section more stable during handling and processing, while not detracting from the quality of bonding with the moulding compound.

In some embodiments, instead of or in addition to pre-impregnating (wetting) of the fibre portion 312 of a given tie 310 with resin, the fibre portion 312 may be pre-impregnated (wetted) or otherwise embedded in with moulding compound of a similar composition to the charges of moulding compound 358 introduced into the mould tool 142, 143.

Thus, in some embodiments, the one or more fibres of a fibre portion may be wetted with resin. In some embodiments, the one or more fibres of a fibre portion may be wetted with moulding compound. In some embodiments the one or more fibres of a fibre portion may be wetted with resin and provided with a coating of moulding compound.

In some embodiments, a fibre portion 312 pre-impregnated (pre-wetted) with moulding compound 358 may also be part-cured provided part-curing does not adversely affect handling of tie 310 (such as flexibility of the fibre portion 312), the moulding process or one or more properties of the subsequently formed component.

FIG. 8 shows a tie 310' similar to that of the embodiment of FIG. 7 in which the fibre portion 312' comprises a plurality of fibres 312f'. The fibres 312f' have been impregnated with resin 357' of the type used in the moulding compound from which a component comprising the tie 310' is formed, and the resulting structure coated in moulding compound 358'.

Other arrangements may be useful.

It is to be understood that in some embodiments, moulding compound 158 may be injected into the cavity 110C in a mould tool 140 in an injection moulding operation rather than being placed in the cavity 110C in the form of charges ('pieces' or 'lumps') of moulding compound 158. Other arrangements may be useful in some alternative embodiments.

FIG. 9 shows a vehicle 100 according to an embodiment of the present invention in which a component 160 (not shown) formed according to an embodiment of the present invention has been installed.

It is to be understood that, where one or more components that each have one or more ties according to an embodiment of the present invention provided therein are to be joined to another component, the location at which each of one or more ties is provided in a given component may be arranged such that, when two or more components are joined together, for example be means of adhesive or one or more mechanical fixing elements, respective peg members and/or fibre portions of adjacent components are aligned with one another so that stresses transmitted by a tie on one component are transmitted across an interface between components to a tie in an adjacent component.

FIG. 10 is a schematic illustration of an assembly 460A of a pair of components 460, 560 each having respective ties 410, 510 (not drawn to scale) provided therein, the ties 410, 510 being of the type illustrated in FIG. 6. It can be seen that, with the components joined together, peg members 414b, 514A of respective tie 410, 510 are substantially adjacent one another. This permits forces born by the tie 410 of one component 460 to be transmitted to the corresponding tie 510 of the other component 560, enhancing one or more mechanical properties of the assembly 460A. The locations of peg members (such as peg members 414A, 514A) may be referred to as 'nodes'.

FIG. 11 is a schematic illustration of an assembly 660A of a pair of components 610, 710 each having respective ties 612, 712 (not drawn to scale) provided therein, the ties 612, 712 again being of the type illustrated in FIG. 6. It can be seen that, with the components joined together, respective ties 612, 712 are arranged to overlap when the components 610, 710 are viewed in plan view and in section AA of FIG. 11. This facilitates the transmission of forces born by the tie 612 of one component 610 to the corresponding tie 712 of the other component 710, enhancing one or more mechanical properties of the assembly 660A.

It is to be understood that the location(s) at which a given tie should be placed within a given component may be determined by a consideration of the location of portions of a given component that experience the highest levels of stress or strain under a given loading condition. Finite element analysis (FEA) may for example be used to calculate the amount of stress or strain to which a given volume element (voxel) of a component is subject in order to determine where to place a tie. In one methodology, voxel elements having a stress or strain level below a certain threshold value may be eliminated from a computer model of a given component, the threshold value of stress or strain being set so as to show the locations of material that are considered to require reinforcement by means of a tie. The required locations and arrangements of ties may then be calculated so as to provide reinforcement in these areas. The regions may be found to be elongate in shape, and be referred to as 'flux lines' in some embodiments. The level of stress or strain in a component may vary as a function of location along a given flux line.

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.

Throughout the description and claims of this specification, the words "comprise" and "contain" and variations of the words, for example "comprising" and "comprises", means "including but not limited to", and is not intended to (and does not) exclude other moieties, additives, components, integers or steps.

Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.

Features, integers, characteristics, compounds, chemical moieties or groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith.

Claims

CLAIMS: 1 A method of forming a vehicle component comprising: introducing at least one reinforcing tie into a mould tool, the tie comprising at least one continuous reinforcing fibre portion; coupling the at least one continuous reinforcing fibre portion, secured between locations, to the mould tool at a plurality of spaced apart locations of the mould tool; and introducing moulding material to the mould tool whereby the moulding material is moulded by the mould tool and the tie is at least partially encapsulated by the moulding material.
2. A method according to claim 1 whereby the tie is provided with at least two retention portions at axially spaced locations of the tie, coupling the at least one continuous reinforcing fibre portion to the mould tool comprising coupling the retention portions to the mould tool at corresponding spaced apart retention portion locating features of the mould tool.
3. A method according to claim 1 or claim 2 wherein introducing the at least one continuous reinforcing fibre portion comprises introducing the at least one continuous reinforcing fibre portion when the mould tool is in an open condition and subsequently closing the mould tool whereby the mould tool is caused to assume a closed condition.
4. A method according to claim 3 wherein introducing moulding material to the mould tool comprises introducing moulding material to the mould tool whilst the mould tool is in the open condition.
5. A method according to claim 3 or claim 4 wherein introducing moulding material to the mould tool comprises introducing moulding material to the mould tool whilst the mould tool is in the closed condition.
6. A method according to any preceding claim wherein the mould tool is provided with locating features for retaining the retaining portions of the tie in a substantially fixed position when moulding material is moulded by the mould tool and the tie is at least partially encapsulated by the moulding material.
7. A method according to any preceding claim comprising allowing the moulding material to cure.
8. A method according to any preceding claim comprising providing the at least one continuous reinforcing fibre portion whereby the at least one continuous reinforcing fibre portion comprises at least one substantially continuous fibre element.
9. A method according to any preceding claim comprising providing the at least one continuous reinforcing fibre portion whereby at least one said at least one continuous reinforcing fibre portion comprises a plurality of fibre elements joined to form a continuous reinforcing fibre portion.
10. A method according to claim 9 whereby a length of at least two of the fibre elements of at least one continuous reinforcing fibre portion is less than a length of a path of the at least one continuous reinforcing fibre portion between the spaced apart locations of the mould tooth to which the continuous reinforcing fibre portion is secured.
11. A method according to any preceding claim wherein the moulding material comprises lengths of a material in the form of fibre elements embedded in a plastic moulding compound that deforms plastically to conform to an internal cavity of the mould tool defining a shape of the component to be moulded when the mould tool is closed.
12. A method according to claim 11 wherein the fibre elements comprised by the moulding material are of a length less than 10mm.
13. A method according to claim 11 wherein the fibre elements comprised by the moulding material are of a length in the range from 3mm to 50mm, optionally in the range from 5mm to 40mm, optionally in the range from 10mm to 30mm, optionally in the range from 15mm to 25mm.
14. A method according to any one of claims 8 to 13 whereby a fibre element comprises one selected from amongst a carbon fibre element and a glass fibre element.
15. A method of assembling a motor vehicle comprising: forming a component according to any preceding claim; and incorporating the component into the motor vehicle in a process of motor vehicle assembly.
16. A motor vehicle component comprising a plastics material and at least one reinforcing tie spanning a length within the component, the tie comprising at least one continuous reinforcing fibre portion, wherein the tie is at least partially encapsulated by the plastics material.
17. A component according to claim 16 wherein the continuous reinforcing fibre portion is substantially surrounded along substantially the whole length thereof by said plastics material.
18. A component according to claim 16 or 17 wherein the tie comprises first and second retention portions coupled to the at least one continuous reinforcing fibre portion at opposite ends thereof.
19. A component according to claim 18 wherein the first and second retention portions each have at least a portion exposed at a free surface of the component.
20. A component according to claim 19 wherein the at least a portion of the first and second retention portions exposed at a free surface of the component comprises a tool coupling portion arranged to couple the retention portions to a wall of a mould tool.
21. A component according to any one of claims 18 to 20 wherein at least one of the retention portions comprises joining means for joining the component to another component.
22. A component according to claim 21 wherein the joining means comprises at least one selected from amongst a threaded shaft, an externally threaded shaft, a shaft with an internal bore and a shaft with a threaded internal bore.
23. A vehicle comprising a component according to any one of claims 16 to 22.