TECHNICAL FIELD

The present disclosure relates to vehicle tailgates and is particularly applicable to tailgates with a polymer-based construction.

BACKGROUND

Vehicle tailgates such as the type installed at the rear end of a pickup truck bed are conventionally constructed from multiple pieces of sheet metal welded together and sealed along the weld seams. While polymeric materials have made headway in replacing metals in many vehicle applications, their application in tailgates has been limited due to difficulties with meeting cost targets and balancing mechanical requirements with weight reduction.

SUMMARY

In accordance with various embodiments, a vehicle tailgate includes an outer panel, an inner panel, a latching mechanism, and a trim panel. At least a portion of the latching mechanism is located between the inner and outer panels, and the trim panel closes off a space defined between ends of the inner and outer panels. The trim panel is removable to provide service access to the portion of the latching mechanism located between the inner and outer panels.

In some embodiments, the outer panel, the inner panel, and the trim panel are each formed from polymer-based materials.

In some embodiments, the inner panel or the trim panel is formed from a polypropylene material with 10 wt% to 45 wt% carbon fiber reinforcements.

In some embodiments, the latching mechanism comprises an actuator that includes the portion of the latching mechanism located between the inner and outer panels.

In some embodiments, the latching mechanism includes a handle assembly, a latch, and a linking portion coupling the handle assembly to the latch. The handle assembly, the latch, and the linking portion are simultaneously accessible through the space defined between ends of the inner and outer panels when the trim panel is removed.

In some embodiments, the inner panel includes a base portion extending between lateral ends of the tailgate and reinforcing ribs extending from the base portion toward the outer panel. The reinforcing ribs are formed integrally with the base portion as a single piece of molded material comprising a polymer.

In some embodiments, the vehicle tailgate includes a network of reinforcing ribs extending between the inner panel and the outer panel and between lateral ends of the tailgate. The inner panel has a corrugated structure and the outer panel is non-planar. The reinforcing ribs have a honeycomb structure in which one end of each cell of the honeycomb structure is shaped to match a contour of the corrugated structure and an opposite end of each cell of the honeycomb structure is shaped to match a contour of an interior side of the outer panel.

In some embodiments, the vehicle tailgate includes a honeycomb structure of reinforcing ribs extending between the inner panel and the outer panel. The honeycomb structure extends at least 80% of a distance between lateral end walls of the inner panel.

In some embodiments, a honeycomb structure forms a lateral beam portion extending between lateral end walls of the inner panel.

In some embodiments, a honeycomb structure extends at least 80% of a distance between the trim panel and a bottom wall of the inner panel.

In some embodiments, the tailgate does not include a metallic structural component extending between opposite lateral ends of the tailgate.

In some embodiments, the trim panel is a molded component comprising unidirectional reinforcing fibers extending between lateral ends of the trim panel.

In some embodiments, wherein the inner panel provides a continuous one-piece load surface along an entire width of the tailgate.

In some embodiments, the vehicle tailgate includes metal brackets at opposite lateral ends of the tailgate. Each of the metal brackets is located along an interior side of an end wall of the inner panel and supports a hinge, a cable, and/or a latch of the latching mechanism.

In some embodiments, the vehicle tailgate includes a liner layer overmolded on the trim panel and/or the inner panel.

It is contemplated that any number of the individual features of the above-described embodiments and of any other embodiments depicted in the drawings or description below can be combined in any combination to define an invention, except where features are incompatible. BRIEF DESCRIPTION OF THE DRAWINGS

FIG. l is a perspective view of the outer side of a vehicle tailgate;

FIG. 2 is a perspective view of an opposite inner side of the tailgate of FIG. 1;

FIG. 3 is a cutaway view of the tailgate of FIG. 1;

FIG. 4 is a cutaway view of a variation of the tailgate of FIG. 3;

FIG. 5 is an exploded view of the tailgate of FIG. 4;

FIG. 6 is an enlarged view of a portion of a lateral end of the tailgate;

FIG. 7 is an enlarged view illustrating a cross-section of a top end of the tailgate taken between lateral ends of the tailgate;

FIG. 8 is a cutaway view of another variation of the tailgate; and

FIG. 9 is an exploded view of the tailgate of FIG. 8.

DESCRIPTION OF EMBODIMENTS

The vehicle tailgate described below can be constructed in a relatively simple manner via integration of components so that only a few pieces are required in the assembly without sacrificing tailgate rigidity. The disclosed tailgate construction also offers benefits beyond those normally associated with plastic materials, including serviceability of internal mechanisms in a manner not possible with previous tailgate constructions. For instance, service access to internal tailgate components can be provided along the full width of the assembly without removal of the handle assembly and without the need for access windows or panels on the inner panel of the tailgate. The inner panel can thus be made without seams or gaps, which provides a smooth load surface when the tailgate is in the open position and eliminates crevices and any debris build-up or water leakage associated with such gaps during normal use and cleaning. While the illustrated examples described here relate to a pickup truck tailgate, this disclosure is applicable to any vehicle gate that forms a wall of a vehicle cargo area and that is selectively moveable to provide access to the cargo area from an end of the cargo area.

FIGS. 1 and 2 are perspective views from opposite sides of an exemplary vehicle tailgate 10. The illustrated tailgate 10 forms the rear wall of a pickup truck bed when in the closed position, which is a vertically upright position. In the closed position, opposite lateral ends 12, 14 of the tailgate 10 are concealed by longitudinally extending side walls of the truck bed. The tailgate 10 is moveable to a horizontally extending open position by pivoting about a hinged bottom end 16 by approximately 90 degrees such that a free top end 18 of the tailgate swings away from the truck bed. The free end 18 of the tailgate is at the same vertical position as the hinged end 16 in the open position. A coordinate system is provided in some of the figures in which X is the transverse direction of the vehicle and the tailgate, Y is the longitudinal direction of the vehicle, and Z is the vertical direction. The tailgate 10 is illustrated in the closed position in all of the figures.

FIG. 1 illustrates an outer side of the tailgate 10, and FIG. 2 illustrates an opposite inner side. The outer side is defined at least in part by an outer panel 20, and the inner side is defined at least in part by an inner panel 22. The panels 20, 22 are joined at the top end 18 of the tailgate by a trim panel 24. The tailgate 10 includes a handle or lever 26 at the outer side, which is part of a latching mechanism 28 that also includes one or more latches 30. The latches 30 are located at the lateral ends 12, 14 of the tailgate 10 and are partially concealed by the inner panel 22 in this example. The latches 30 engage mating components on the vehicle body to hold the tailgate 10 in the closed position. The latching mechanism 28 includes one or more additional components (e.g., cables, rods, linkages, pins, springs, etc.) that mechanically couple the handle 26 with the latches 30. These latching mechanism components are located inside the tailgate 10 between the inner and outer panels. The handle 26 is an actuator that disengages the latches 30 from their mating components when a user lifts the handle, thereby allowing the tailgate to be moved toward the open position.

Movement between the open and closed positions is about a pivot axis A, which is defined by hinges 32 at the bottom end 16 of the tailgate 10. The inner panel 22 provides a load surface 34 that is level with a load surface of the truck bed when in the open position. One or more cables, arms, links, cylinders, or other suitable elements may be provided as a positive stop for the tailgate 10 so that the tailgate cannot move beyond horizontal when moved to the open position. The tailgate 10 thus becomes a load bearing structure in the open position to assist in the loading of or transport of cargo in the truck bed. The load surface 34 has a corrugated structure in this example for added structural rigidity and reduced surface contact with cargo that may be slid across the load surface.

FIGS. 3 and 4 are cutaway views of the outer side of the tailgate 10 in which one half of the outer panel 20 is omitted to illustrate the inside of the tailgate 10. The inner panel 22 includes a base portion 36 and end walls 38, 40, along with a bottom wall 42 and a network 44 of reinforcing ribs 46. Interior sides of the inner and outer panels oppose each other across an interior space of the tailgate 10. The base portion 36 includes the above-described corrugated structure and extends laterally between the end walls 38, 40 and from the bottom wall 42 to the separately provided trim panel 24. Each end wall 38, 40 is located at one of the lateral ends 12, 14 of the tailgate 10. The bottom wall 42 is located at the bottom end 16 of the tailgate 10 and interconnects the end walls 38, 40 to form a continuous wall along a portion of the perimeter of the base portion 36 and along the sides and bottom of the tailgate.

The network 44 of ribs includes a plurality of reinforcing ribs 46 arranged in an interconnected fashion between the panels 20, 22. The network 44 spans substantially the entire width of the interior of the tailgate 10, effectively interconnecting the end walls 38, 40 of the inner panel 22 at lateral opposite ends 12, 14 of the tailgate. The network 44 also spans nearly the entire distance of the interior of the tailgate in a direction perpendicular to the lateral direction — i.e., the vertical z-direction when the tailgate is in the closed position. This effectively interconnects the end walls 38, 40 with the bottom wall 42 of the inner panel 22 and interconnects the base portion 36 with all of the walls 38-42 of the inner panel, thus forming an internal structure that provides the tailgate 10 with rigidity in bending and torsion. In these examples, the network 44 of ribs 46 does not extend entirely to the trim panel 24 or interconnect the trim panel with any of the walls 38-42 of the inner panel 22 because the trim panel is removable, as discussed further below.

Each of the walls 38-42 and each of the reinforcing ribs 46 extends from the base portion 36 of the inner panel 22 to a distal end at an interior side of the outer panel 20 and spans the entire thickness of the interior of the tailgate 10. In a preferred embodiment, the inner panel 22 is monolithic — i.e., it is made as one piece from a single material. For example, the inner panel 22, including the base portion 36, the walls 38-42, and the network 44 of reinforcing ribs 46 may be injection molded from a polymer-based material comprising a thermoplastic polymer and, optionally, a filler or reinforcement material such as fiber reinforcements (e.g., glass, carbon fiber, etc.) or mineral. In one embodiment, the inner panel 22 is molded from a polypropylene material reinforced with 10 wt% to 45 wt% carbon fiber. In another embodiment, the inner panel 22 is molded from a polypropylene material reinforced with 20 wt% to 40 wt% carbon fiber. In another example, the inner panel 22 can be compression molded from a polymer-based material comprising a thermosetting polymer with an optional filler or reinforcement material. Reaction injection molding (RIM) or other polymer processing techniques may also be adapted to form the inner panel 22 with the integrated reinforcing rib network.

Each of the rib networks 44 illustrated in FIGS. 3 and 4 includes a lateral beam section 48 interconnected with a plurality of laterally extending ribs 46 and vertically (z-direction) extending ribs. Each of the lateral beam sections 48 includes a honeycomb structure of reinforcing ribs 46 having a cross-section in an x-z plane with interconnected hexagonal shapes. Each lateral beam section 48 is located approximately midway between the bottom wall 42 and the top end 18 of the tailgate 10 and extends between and interconnects the laterally opposite end walls 38, 40 of the inner panel 22. In the example of FIG. 3, the honeycomb structure includes a single row of hexagonally arranged ribs 46 between parallel and continuous laterally extending ribs. In the example of FIG. 4, the honeycomb structure includes multiple rows of hexagonally arranged ribs 46 in which each hexagon shares at least one side with an adjacent hexagon. This highly rigid lateral beam section 48, which can be integrally molded as one piece with the remainder of the inner panel, eliminates the need for additional, separately provided lateral reinforcements. In various embodiments, the reinforcing ribs 46 extend from the base portion of the inner panel 22 completely to an interior side of the outer panel 20 such that no separately formed reinforcing beam or reinforcing panel is present between the distal ends of the ribs and the outer panel. In particular, there is no metallic reinforcing beam or panel extending in the transverse direction within the tailgate.

In both examples, the outermost vertically extending ribs 46 are slanted inward toward the center of the tailgate 10 to provide packaging space for the latches 30 of the latching mechanism 28 and for the routing of a linking portion 50 of the latching mechanism, such as a cable, rod, or other mechanical linkage that extends at least partly between each latch and the handle 26. In various embodiments, including those of FIGS. 3 and 4, the network 44 of ribs 46 does not include any ribs between an internal portion of the latching mechanism 28 and the top end 18 of the tailgate 10. In such embodiments, the trim panel 24 may be removable for service access to the internal portion of the latching mechanism 28. The latching mechanism 28 can thus be serviced without removal of the handle 26 or handle assembly from the outer panel 20. Moreover, service access is provided over the full lateral extent of the latching mechanism 28 rather than only the central part of the mechanism.

This means that an internal portion of the latches 30, the linking portion 50 of the latching mechanism 28, and an internal portion of a handle assembly 52 (including the handle 26) are all simultaneously accessible with the trim panel 24 removed and with the handle assembly still attached. In addition, the removable trim panel 24 is situated such that no gaps or seams are present along the load surface 34, thus enabling a smooth load service for unhindered sliding of cargo thereacross and elimination of debris collection or water leakage that could occur if service access was provided through the inner panel 22. The removable trim panel also provides for ease of assembly, particularly when compared to welded sheet metal panels.

FIG. 5 is an exploded view of the tailgate 10 of FIG. 4 to better illustrate some of its individual components. The tailgate 10 is of relatively simple construction and is formed from three main components, including the outer panel 20, the inner panel 22, and the trim panel 24. The outer panel 20 is primarily decorative and may have the same exterior finish as other exterior body panels of the vehicle. The outer panel 20 includes an opening 54 through which part of the latching mechanism 28 passes. In this example, a portion of the handle assembly 52, which includes the latch-actuating handle 26, passes through the opening 54 when affixed to the outer panel 20.

In a preferred embodiment, the outer panel 20 is made from a polymer-based material, such as an injection moldable thermoplastic material or a compression molded thermoset material. The polymer-based material may be a neat resin containing no reinforcing fillers such as fibers or minerals to achieve a class-A finish suitable for automotive-grade paint finishes. The interior surface of the outer panel 20 may be adhesively bonded to the inner panel 22 along the distal ends of the reinforcing ribs 46 and walls 38-42. Other alternative or additional attachment techniques may be used, such as solvent welding, ultrasonic welding, melt bonding, heat staking, etc. Any of these methods of attachment may seal off the interior of the tailgate from the environment such that a dual-purpose is served, unlike welded metal components which must rely on additional sealant materials for weatherability. While the outer panel 20 is primarily decorative, its attachment to the inner panel 22 and its network of ribs 46 completes a boxed-in structure for further rigidity.

The illustrated tailgate 10 includes metal (e.g., steel or aluminum) reinforcement brackets 55 at its opposite lateral ends. Each bracket 55 extends along nearly the full length of the respective end wall 38, 40 and wraps around the comers formed by each end wall and the bottom wall 42. A flange at the top end of each bracket wraps along the base portion 36 of the inner wall 22 as well, in this example. The brackets 55 provide non-polymeric mounting locations for certain load-bearing components, such as the latches 30 and hinges 32. The tailgate may include a cable pin or bolt 56 affixed to the bracket 55 along one or both lateral ends. In the illustrated example, the brackets 55 are located along the interior side of the walls 38-42 of the inner panel 22. The brackets 55 may be adhesively attached and/or bolted to the inner panel 22 prior to attachment of the outer panel 20. The brackets 55 may be slotted as shown to slide over laterally extending ribs of the inner panel 22. The hinges 32 can then be attached to the inner panel 22 by fasteners extending through the bottom and end walls of the inner panel and engaging the respective brackets.

The trim panel 24 is configured to close off the space between the free top ends of the inner and outer panels. As noted above, the trim panel 24 may be constructed as a removable component to provide service access to the portion of the latching mechanism 28 located between the panels 20, 22. As used herein, “removable” means separable without appreciable damage to the trim panel 24 or to the inner and outer panels such that the trim panel can be reattached along the free end 18 of the tailgate 10 in the same manner it was initially attached. In the illustrated example, bolts, screws or other fasteners pass through fastener openings 58 in the lateral ends of the trim panel 24 to engage the respective end walls 38, 40 of the inner panel 22, as shown in FIG. 6. Similar fasteners may be used along a flange 60 of the trim panel 24 that overlaps the top end of the base portion 36 of the inner panel 22, as shown in FIG. 7. In the example of FIG. 7, a push-in type fastener is illustrated in which a first piece is pushed axially to expand legs of a second piece on the opposite side of the parts to be attached. This type of fastener can be removed by pulling the first piece, which allows the legs on the opposite side of the parts to be forced together to fit back through the fastener openings 58 for removal. Snap features or other attachment features that impart the trim panel 24 with removability may be used along laterally extending flanges, ribs or stand-offs, and/or at lateral ends of the trim panel.

In a preferred embodiment, the trim panel 24 is made from a polymer-based material, such as an injection moldable thermoplastic or a compression molded thermoset material with, optionally, a filler or reinforcement material such as fiber reinforcements (e.g., glass, carbon fiber, etc.) or mineral. In one embodiment, the trim panel 24 is molded from a polypropylene material reinforced with 10 wt% to 45 wt% carbon fiber. In another embodiment, the trim panel 24 is molded from a polypropylene material reinforced with 20 wt% to 40 wt% carbon fiber. In the example of FIG. 5, the trim panel 24 includes a polymeric component 62 with one or more layers of unidirectional tape (UDT) 64 molded into and impregnated with the polymeric component. UDT is a pre-formed sheet of reinforcing fibers (e.g., glass or carbon fibers) that can be molded into or onto a molded component for localized reinforcement. The fibers of a UDT are generally continuous along the entire length of the tape and, in turn, along the entire section of the component they reinforce. In this case, the UDT can provide the trim panel 24 with a locally reinforced layer that can withstand threaded fasteners or other attachments over the life of the product better than the polymeric component 62 alone. UDT is an optional component that can be included when additional rigidity is required. This type of localized reinforcement can be very effective in terms of structural design and molding processes - i.e., it can be more efficient and economical than reinforcing the entire component and/or using discontinuous fibers.

Referring again to FIG. 5, the tailgate 10 may include a liner layer 66 along the load surface of the inner panel 22 and/or along the external surface of the trim panel 24. The liner 66 may be overmolded directly onto the inner panel 22 and or the trim panel 24 prior to assembly of the tailgate. As used herein, overmolding includes co-molding two different materials in the same molding tool and/or placing a molded part into a separate overmolding tool to form the overmolded layer. It is also possible to mold a base portion (e.g., the inner panel 22 or trim panel) in a cavity between two mold halves and then change only one mold half to form the molding cavity for the overmolded layer. The liner 66 is preferably a toughened polymer-based material with an elastomeric component that resists hard impacts without breaking. The liner layer 66 is also illustrated in the end view of the top end 18 of the tailgate 10 of FIG. 6 and in the cross-sectional view of the top end of the tailgate of FIG. 7. The overmolded liner layer 66 eliminates the need for expensive paint processes and/or the need for a separately attachable molded liner element.

FIGS. 6 and 7 depict one embodiment of the trim panel 24 and its interconnection with the inner and outer panels 22, 20. The trim panel 24 has a first flange 60 that overlaps a portion of the inner panel 22, and a second flange 68 that overlaps a portion of the outer panel 20. In this particular example, each flange 60 and 68 is a double flange that defines respective lateral grooves 70, 72 in the trim panel 24. The top or free edge of each of the inner and outer panels fits within these grooves 70, 72 to positively locate the trim panel 24 with respect to the inner and outer panels and align the fastener holes 58 of each. The double flanges 60, 68 also provide a passive fluid seal such that a sealant material is not required, which would interfere with the removability of the trim panel 24. Laterally extending stand-off features 74, 76 may be provided along the interior sides of the inner and outer panels for receiving (i.e., landing) the double flanges 60, 68, positively locating the trim panel in the z-direction, and/or for additional sealing surface area. In the illustrated example, an inner portion 75 of the flange 60 is discontinuous in the transverse (x) direction and thereby forms tabs that extend through openings in the stand-off feature 76. The tabs can be attachment tabs. Other overlapping arrangements of the various edges and flanges of the three panels 20-24 are possible. A tailgate 10 is thus provided that can be constructed almost entirely of polymer-based materials. Notably, the above-described tailgate 10 can also be constructed without any structural metallic component that extends entirely between its opposite lateral ends 12, 14, although such components are not necessarily excluded in all embodiments. The only metal components in such an all-polymer construction are the load-bearing hinges 32, the brackets 55 to which the hinges are attached, and portions of the latching mechanism 28, such as the latches 30 and other internal portions of the mechanism. Skilled artisans will recognize that one or more of the described panels 20-24 may be made from a material other than a polymer- based material while still achieving the benefits of the removable trim panel along the free end of the tailgate for serviceability and/or assembly of the latching mechanism. For instance, any of the above-described panels 20-24 may be made from or include a layer of sheet metal, such as a steel or aluminum alloy. In some cases, the above-described network 44 of reinforcing ribs may be formed from a polymer-based material and disposed between inner and/or outer panels that are not made from polymer-based materials. Further, certain advantages may be realized with tailgates or other moveable cargo walls that do not include manual latching mechanisms. For instance, a powered tailgate can be constructed with no manual handle assembly along the outer panel while preserving the nearly all-polymer construction and/or a removable trim panel along a free end of the tailgate that provides service access for some portion of an electric or electromechanical latching mechanism.

FIGS. 8 and 9 are respective cutaway and exploded views of the tailgate 10 with a variation of the network 44 of ribs 46. The illustrated network 44 includes a honeycomb structure occupying nearly the entire area (e.g., about 85-90%) of the space between the base 36 of the inner panel 22 and the outer panel 20. The honeycomb structure of reinforcing ribs 46 may extending at least 80% of the distance between the lateral end walls 38, 40 of the inner panel 22, as is also the case in the examples of FIGS. 3-5. While the honeycomb structure of FIGS. 3-5 forms a lateral beam portion 48, the honeycomb structure of FIGS. 8 and 9 extends at least 80% of the distance between the trim panel 24 and the bottom wall 42 of the inner panel 22

The honeycomb portion of the network 44 of ribs in FIGS. 8 and 9 is framed along the bottom by the bottom wall 42 of the inner panel, along transversely opposite sides by vertical ribs 78, 80 running generally parallel with the end walls 38, 40 of the inner panel, and along the top by a transverse rib portion 82 running generally parallel with the trim panel 24. For most of its length, the transverse rib portion 82 is spaced from the trim panel 24 by an amount sufficient to accommodate the linking portion 50 of the latching mechanism and is offset at its transverse center only enough to accommodate the internal portion of the handle assembly 52. For most of their length, the vertical ribs 78, 80 are spaced from the respective end walls 38, 40 of the inner panel 22 by an amount sufficient to accommodate the brackets 55, sloping away from each end wall at the top only enough to accommodate the latches 30.

In comparison with the examples of FIGS. 3 and 4, the locations of the latches 30 and the handle assembly 52 of FIGS. 8 and 9 are closer to the trim panel 24. Locating these latching mechanism components as close as possible to the free end of the tailgate 10 maximizes the area available for the network 44 of ribs and minimizes the required length of the linking portion 50.

Some of the ribs 46 of the network 44 of ribs have apertures 84 formed therethrough to accommodate internal portions of other tailgate components. In this particular example, the apertures 84 are formed through transversely extending ribs of the honeycomb structure to accommodate electrical wiring for a rear-facing camera assembly 86.

In embodiments where the inner panel 22 — including the base 36, walls 38-42, and the network 44 of ribs 46 — is molded in one piece from a polymer-based material, certain combinations of features can be included that are not possible with metallic materials. For example, the base 36 may have a corrugated configuration as in all of the illustrated embodiments with the network 44 of ribs following the contour of the non-planar shape of the corrugated base. While honeycomb structures may be possible with metallic materials, for example, such structures are generally limited to flat or planar configurations. Additionally, the distal ends of the ribs of the network of ribs can also be made to follow the contour of the inner surface of the outer panel 20. As such, the reinforcing ribs 46 may have a honeycomb structure in which one end of each cell of the honeycomb structure is shaped to match the contour of the corrugated structure of the inner panel, while an opposite end of each cell of the honeycomb structure is shaped to match a contour of an interior side of the outer panel.

It is to be understood that the foregoing description is of one or more embodiments of the invention. The invention is not limited to the particular embodiment(s) disclosed herein, but rather is defined solely by the claims below. Furthermore, the statements contained in the foregoing description relate to the disclosed embodiment(s) and are not to be construed as limitations on the scope of the invention or on the definition of terms used in the claims, except where a term or phrase is expressly defined above. Various other embodiments and various changes and modifications to the disclosed embodiment(s) will become apparent to those skilled in the art.

As used in this specification and claims, the terms “e.g.,” “for example,” “for instance,” “such as,” and “like,” and the verbs “comprising,” “having,” “including,” and their other verb forms, when used in conjunction with a listing of one or more components or other items, are each to be construed as open-ended, meaning that the listing is not to be considered as excluding other, additional components or items. Other terms are to be construed using their broadest reasonable meaning unless they are used in a context that requires a different interpretation.