The present invention in general relates to composite vehicle components and in particular, to unitary reinforced composite based vehicle components with an integral electrical harness with embedded electronics and associated terminations.
Weight savings in the automotive, transportation, and logistics-based industries has been a major focus in order to make more fuel-efficient vehicles both for ground and air transport. In order to achieve these weight savings, light weight composite materials have been introduced to take the place of metal structural and surface body components and panels. Composite materials are materials made from two or more constituent materials with significantly different physical or chemical properties, that when combined, produce a material with characteristics different from the individual components. The individual components remain separate and distinct within the finished structure. A composite material may be preferred for many reasons: common examples include materials which are stronger, lighter, or less expensive when compared to traditional materials.
As vehicles are increasingly platforms for ever more complex sensors and computerized systems, the complexity of a vehicle electrical harness and the time needed for installation have also increased. Traditionally, sets of wires are cut to predetermined lengths and tied into bundles with connectors that must then be joined to structural components during vehicle assembly. Such harnesses have become increasingly impractical and time consuming to couple to not only vehicle electrical components, but also sensors and central processing units (CPUs). Traditional electrical harnesses also suffer from vibrationally induced wear caused by vehicle operation. The shorting of a wire within an electrical harness is difficult to repair.
As part of an effort to reduce vehicle weight, manufacturing has moved towards composite materials. These composite materials include a matrix material that surrounds and supports the reinforcement materials by maintaining their relative positions. The reinforcements impart their special mechanical and physical properties to enhance the matrix properties. A synergism produces material properties unavailable from the individual constituent materials, while the wide variety of matrix and strengthening materials allows the designer of the product or structure to choose an optimum combination.
Commercially produced composites often use a polymer matrix material that is either a thermoplastic or thermoset resin. There are many different polymers available depending upon the starting raw ingredients which may be placed into several broad categories, each with numerous variations. Examples of the most common categories for categorizing polymers include polyester, vinyl ester, epoxy, phenolic, polyimide, polyamide, polypropylene, PEEK, and others.
The use of fiber and particulate inclusions to strengthen a matrix is well known to the art. Well established mechanisms for the strengthening include slowing and elongating the path of crack propagation through the matrix, as well as energy distribution associated with pulling a fiber free from the surrounding matrix material. In the context of sheet molding composition (SMC) formulations, bulk molding composition (BMC) formulations, and resin transfer molding (RTM); hereafter referred to collectively as “molding compositions”, fiber strengthening has traditionally involved usage of chopped glass fibers. There is a growing appreciation in the field of molding compositions that replacing in part, or all of the glass fiber in molding compositions with carbon fiber can provide improved component properties.
Fiber-reinforced composite materials can be divided into two main categories normally referred to as short fiber-reinforced materials and continuous fiber-reinforced materials. Continuous reinforced materials often constitute a layered or laminated structure. The woven and continuous fiber styles are typically available in a variety of forms, being pre-impregnated with the given matrix (resin), dry, uni-directional tapes of various widths, plain weave, harness satins, braided, and stitched. Various methods have been developed to reduce the resin content of the composite material, by increasing the fiber content. Typically, composite materials may have a ratio that ranges from 60% resin and 40% fiber to a composite with 40% resin and 60% fiber content. The strength of a product formed with composites is greatly dependent on the ratio of resin to reinforcement material. The construction method of selective placement of commingled fiber bundles being stitched in place offers new opportunities to integrate electrical wiring within a vehicle component.
While there have been many advances in composite materials with embedded electrical conductors there continues to be a need for simplified through hole terminations and blind via terminations that connect to external electrical harnesses, electrical components, and additional composite structures having embedded conductors.
A form for a vehicle component is provided that includes a commingled fiber bundle composed of a reinforcement fiber. The reinforcement fiber being glass fibers, aramid fibers, carbon fibers, or a combination thereof. The commingled fiber bundle is laid out in a two-dimensional base layer that defines a shape of the form. A conductive fiber or wire laid in a pattern on the two-dimensional base layer to provide electrical continuity across the form. At least one conductive contact or pad area is built up with overlying layers of the conductive fiber or wire on said two-dimensional base layer. A successive layer formed with the commingled fiber bundle in contact with said two-dimensional layer so as to embed the conductive fiber or wire and at least one conductive contact or pad area. A through hole aperture corresponding to each of the at least one conductive contact or pad areas. A conductive fastener is inserted into each of the through hole apertures. The conductive fastener is in electrical communication with the corresponding conductive contact or pad area.
A method of forming a unitary reinforced composite component is provided that includes a form being placed onto a mold platen having a shape. The form is heated to assume the shape of the mold platen. The perform is then cooled until solidified. The shaped form is then removed from the mold platen.
The subject matter that is regarded as the invention is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other objects, features, and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which:
The present invention has utility as a through hole or blind via termination for embedded conductive fiber or wire that is integrated within a laminate structure of a composite part. In embodiments of the invention, the conductive fiber or wire is laid in a pattern to provide electrical continuity across the composite part. At the ends of the conductive fiber or wire, extra fiber or wire material is added across an area set by manufacturing tolerances to establish a set of contact points or conductive pads. In specific embodiments selective commingled fiber bundle positioning (SCFBP) may be used to lay the conductive fiber or wire in a pattern on the surface of a laminate structure. The laminate structure is molded with the conductive fiber or wire within. Holes are drilled through the areas of added conductive fiber or wire that form the contact points or conductive pads, exposing the core of the conductive fiber or wire. A conductive fastener, such as a copper rivet, is installed in the drilled hole, extending electrical continuity to the conductive fastener and providing an electrical surface termination. Conductive materials, such as a wiring harness, can then be connected to the installed conductive fastener to further extend the electrical continuity to other circuitry components.
Specific embodiments of the invention utilize a unitary reinforced composite based panel component, and methods of construction thereof inclusive of electrical wiring and associated embedded electrical components. A vehicle component is prepared with resort to selective commingled fiber bundle positioning (SCFBP) to selectively place commingled fibers that are in some inventive embodiments enriched in carbon fiber as a reinforcement relative to other region that rely on a relatively higher percentage of glass fiber reinforcement while internalizing electrical wiring and associated electrical components within the vehicle part. By providing external terminations to an internalized or an external electrical harness function for a vehicle part, vehicle assembly is simplified and vibrationally induced wear observed in a traditional electrical harness is eliminated.
In specific inventive embodiments, commingled reinforcing fibers of glass, carbon, polyaramid, or a combination thereof are used to form a yarn that has predictable strength, and where the ratio of different fiber types is varied to create different properties along a given length. According to embodiments, the commingled fiber-based yarn optionally also includes a plurality of thermoplastic threads commingled with the reinforcing fibers in the yarn. The commingled fiber-based yarn may be used in the formation of the SCFBP forms and are able to be embroidered directly into complex shapes thereby eliminating trimming waste and inefficient usage of comparatively expensive carbon fiber. In specific inventive embodiments, SCFBP forms include from 3 to 20 layers that vary in fiber types in three dimensions (3D). Electrically conductive insulated wire is also stitched by the SCFBP process into the form to create preselected electrical pathways. The final panel is them formed by melting any thermoplastic fibers within the SCFBP form in contact with at least one mold platen complementary to the finished vehicle component to form a vehicle panel such as a dashboard, body panel, door component, roof components, or decklids.
It is to be understood that in instances where a range of values are provided that the range is intended to encompass not only the end point values of the range but also intermediate values of the range as explicitly being included within the range and varying by the last significant figure of the range. By way of example, a recited range of from 1 to 4 is intended to include 1-2, 1-3, 2-4, 3-4, and 1-4.
SCFBP-technology offers several advantages including:
As used herein, a veil includes woven sheets, non-woven sheets, and films of thermoplastics, glass, or aramids; or woven sheets, non-woven sheets of carbon fibers.
As used herein, any reference to weight percent or by extension molecular weight of a polymer is based on weight average molecular weight.
As used herein, the term melting as used with respect to thermoplastic fibers or thread is intended to encompass both thermofusion of fibers such that a vestigial core structure of separate fibers is retained, as well as a complete melting of the fibers to obtain a homogenous thermoplastic matrix.
Commingled fibers as a roving are made up of commingled reinforcing fibers, illustratively including those made of carbon, glass, or aramid fibers, and optionally thermofusible fibers which serve to provide a matrix in a composite material made of both reinforcing and matrix fibers. The optional matrix fibers, being of a thermofusible nature may be formed from material such as, for example, polyamide, polypropylene, polyester, polyether ether ketone, polybenzobisoxazole, or liquid crystal polymer. The reinforcing fibers may also be of a material that is meltable with the proviso that melting occurs at a temperature which is higher than the any matrix fibers so that, when both fibers are used to create a composite, at the temperature point at which melting of the matrix fibers occurs, the state of the reinforcing fibers is unaffected.
According to embodiments the commingled fibers are made up of only reinforcing fibers and not thermoplastic fiber. The reinforcement fibers in a commingled fiber bundle being glass fibers, polyaramid, carbon fibers, or a combination of any of the aforementioned. It is appreciated that the commingled fibers are either parallel to define a roving or include some fibers that are helically twisted to define a yarn. It is appreciated that the physical properties of reinforcing fibers retained in a helical configuration within a fixed matrix of a completed vehicle component are different than those of a linear configuration, especially along the reinforcing fiber axis.
According to further embodiments, the commingled fibers used in the present invention are composed of both thermoplastic fibers and a reinforcement fiber. Thermoplastic fibers operative herein illustratively includes, polypropylenes, polyamides, polyesters, polyether ether ketones, polybenzobisoxazoles, polyphenylene sulfide; block copolymers containing at least of one of the aforementioned constituting at least 40 percent by weight of the copolymer; and blends thereof. The optional thermoplastic fibers are appreciated to be recycled, virgin, or a blend thereof. The thermoplastic fibers in a commingled fiber bundle constitute from 20 to 80 weight percent of the commingled fibers in the present invention. The relative number of reinforcing fibers relative to any thermoplastic fibers present is highly variable in the present invention in view of the disparate diameters of glass fibers, polyaramid fibers, and carbon fibers.
An inventive form is created by laying out one or more commingled fiber bundles on a substrate as a two-dimensional base layer that defines a shape of the form with stitching applied to retain the commingled fibers in a desired placement on the substrate. As is conventional to SCFBP, the substrate can be removed after production of the form, else it is retained and thereby incorporated into the resulting vehicle component. According to embodiments of the present invention, the stitching thread is a thermoplastic thread, glass fiber thread, carbon fiber thread, aramid fiber thread, a metal wire, or a combination thereof. The thread diameter and thread material used for stitching are variables that are readily selected relative to the properties of commingled fiber bundle and the desired properties of the resulting preform and vehicle component. In certain inventive embodiments, the stitching is a thermoplastic thread. The thermoplastic thread in some inventive embodiments is formed of the same thermoplastic present in the commingled fiber bundle. It is appreciated that the thread diameter and melting temperature of the thread used for stitching are variables that are readily selected relative to the properties of the commingled fiber bundle.
As shown in
As a result of the present invention, the form 210 includes specific features such as the notch region 132 that conventionally would be cut from a base piece. In this way, the present invention eliminates the cutting step, as well as the associated waste generation while including electrical wiring within the form. In addition to the substantially linear pattern of commingled fiber bundle positioning depicted in
If zero degrees is defined as the long axis of the base layer 124, the subsequent layers are overlaid at angles of 0-90°. For example, an angular displacement between adjacent layers is 450 resulting in a 0-45-90-45-0 pattern of layers. Further specific patterns illustratively include 0-45-90-45-0, 0-45-60-60-45-0, 0-0-45-60-45-0-0, 0-15-30-45-60-45-30-15-0, and 0-90-45-45-60-60-45-45-90-0. While these exemplary patterns are for from 5 to 10 layers of directional SCFBP, it is appreciated that the form 210 may include from 3 to 20 layers. It is appreciated that the form layers may be symmetrical about a central layer, in the case of an odd number of layers, or about a central latitudinal plane parallel to the players.
The stitching 122 or 122′ is applied with a preselected tension, stitching diameter, stitch spacing. The stitching 122 or 122′ is typically present in an amount of from 0.1 to 7 weight percent of the commingled fiber bundle 112′ or wiring 121, respectively.
While
A cross-sectional view of an exemplary form similar to form 210 is shown in
As shown in
While the inclusion of a PCB 312 in a form is illustrated in
According to embodiments of the present invention, an inventive preform is suitable to use with any known composite component processing technique, such as RTM, LCM, thermoplastic overmolding, injection molding, and the like.
A fiberglass panel 600′ as shown in
The foregoing description is illustrative of particular embodiments of the invention, but is not meant to be a limitation upon the practice thereof. The following claims, including all equivalents thereof, are intended to define the scope of the invention.
This application is a non-provisional application that claims priority benefit of U.S. Provisional Application Ser. No. 63/390,019 filed Jul. 18, 2022; the contents of which are hereby incorporated by reference.
Number | Date | Country | |
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63390019 | Jul 2022 | US |