Patent Description:
One of the current trends in the automobile industry is to lower vehicle weight to help achieve better fuel economy, thus helping to meet fuel economy standards and to offset the higher fuel prices. Another trend is that there is a broader range of vehicle models, which in turn reduces the volume of vehicles produced on a per model basis. Liftgates are traditionally made from stamped steel panels that are heavy and have a high tooling cost and are susceptible to corrosion. Sheet Molding Compound (SMC) is an alternative to steel for the inner and outer panels of the liftgate. Using SMC has several manufacturing concerns related to the material and process. Steel and SMC liftgates have a mass penalty over thermoplastics. There are also styling restrictions with traditional sheet metal and SMC components.

In another aspect of the invention, it is desirable to provide steel wire reinforcements between and connected with the inner and outer panels in order to further strengthen the liftgate. Traditionally steel wires or cables have been used to hold the liftgate together during a collision. However, the traditional steel cables do not provide any type of strengthening features. It is therefore desirable to develop and provide new strengthening features either formed within the inner and outer panels are connected between the inner and outer panels that can be used to strengthen the overall liftgate structure as well as strengthen and support connection accessories such as light modules, door latches etc..

In yet another aspect of the invention, Rear doors of SUVs, vans and other vehicles are complex to engineer. They tend to be large areas which require hinge attachment points for opening and closing of the doors. The doors must seal to keep the elements out and require stiffness and strength for operating and sealing of the doors but also requiring as light of weight as possible since they have to be supported by hinges. Therefore, robust hinge attachment points capable of holding the weight of doors, dampening struts, latches, and handles are required.

<CIT> discloses a vehicle door arranged at the rear, with a lower part and an upper part adjoining the lower part and having a window pane, the upper part being arranged on the lower part so as to be pivotable about a first horizontal axis. The tailgate is arranged so as to be pivotable laterally outwards, and that its upper part, when the tailgate is open, can be placed against the inner side of the lower part or is arranged so as to be foldable into a corresponding recess of the inner side of the lower part.

<CIT> discloses a sliding door <NUM> for vehicles with a space frame formed from an extruded aluminum tube to which inner <NUM> and outer <NUM> aluminum door panels are attached.

<CIT> discloses a door for a vehicle with a structural tubular frame member having side members which terminate in laterally extending foot portions with terminal ends.

<CIT> discloses a liftgate for a vehicle comprising an upper gate which at the top is pivotally connectable with the vehicle, and a lower gate which at the bottom is pivotally and releasably connectable with the vehicle.

<CIT> discloses a vehicle rear door, in particular tailgate or revolving rear door, having a frame designed as a metal profile, having at least one outer trim part and at least one pane. The frame is bonded onto an inner part, and the inner part (and/or the pane) forms the entire bearing surface for sealingly bearing on a body seal.

The invention proposes a vehicle door comprising the features of claim <NUM>. In a preferred embodiment the door is a swingdoor which opens from the center to the outside.

The door construction of the present invention provides a vehicle door with very good mechanical performance with respect to torsional and bending stiffness. It provides good crash performance and metal reinforcement at latch, strut, ball joint, and hinge points. The door uses tubes and stamped sheet metal parts and is easier and cheaper to manufacture. Additionally, the complete assembly can be easily adjusted for needed dimensions/tolerance requirements in welding process.

Another embodiment of the invention relates to a composite liftgate structure having an inner panel formed of composite material and an outside surface with a perimeter surface area that is adjacent a perimeter edge of the structural composite inner panel. There is a metal hybrid reinforcement connected to the perimeter surface area, wherein the metal hybrid reinforcement forms a closed ring around a perimeter of the inner panel thereby providing enhanced strength to the composite liftgate structure. There is also at least one outer panel connected to the inner panel, wherein the metal hybrid reinforcement is positioned between the inner panel and the at least one outer panel.

The following description of the preferred embodiment is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.

Referring now to <FIG> an exploded side perspective view of a non-claimed composite liftgate <NUM> having a composite liftgate structure <NUM>. The composite liftgate structure <NUM> is a portion of the composite liftgate <NUM> that adds structure and strength to the composite liftgate <NUM>. The composite liftgate structure <NUM> includes an inner panel <NUM> formed of composite material having an outside surface <NUM> with a perimeter surface area <NUM> that is adjacent a perimeter edge <NUM> of the inner panel <NUM>.

The composite liftgate structure <NUM> further includes a metal hybrid reinforcement <NUM> that is connected to the inner panel <NUM> using adhesives, welding, or a plurality of mechanical fasteners. The metal hybrid reinforcement <NUM> is formed of steel, aluminum, or combinations thereof. It is also within the scope of this disclosure for the metal hybrid reinforcement <NUM> to be formed of other metals or a combination of metals and composite materials depending on the needs of a particular application. The metal hybrid reinforcement <NUM> is connected to the perimeter surface area <NUM>. The perimeter surface area <NUM> is an area on the outside surface <NUM> that is adjacent the perimeter edge <NUM> and has a large enough area suitable for connecting to the outside surface <NUM> of the inner panel <NUM>.

The term "hybrid" when referring to the metal hybrid reinforcement <NUM> refers to the variety of different cross-sectional shaped pieces on the metal hybrid reinforcement <NUM> that allows different components to be attached, which will now be described. Referring also to <FIG> and <FIG> the metal hybrid reinforcement <NUM> includes a first tube section <NUM> with a first end <NUM> and a second end <NUM>, and a second tube section <NUM> with a first end <NUM> and second end <NUM>. The first tube section <NUM> and second tube section <NUM> as shown have a circular cross-section with a hollow bore in the middle, however, it is within the scope of this disclosure for the cross section to have a different shape. A latch reinforcement <NUM> is connected between the first tube section <NUM> and second tube section <NUM> at the respective second end <NUM>, <NUM>. The connection between the latch reinforcement <NUM> and the first tube section <NUM> and second tube section <NUM> is a welded connection, however, it is within the scope of this disclosure for another suitable connection to be used such as, but not limited to adhesives and mechanical connections. The latch reinforcement <NUM> has a latch mounting surface <NUM> with legs <NUM>, <NUM> extending therefrom that wrap around and rest against a portion of the outer circumference of the first tube section <NUM> and second tube section <NUM>. The legs <NUM>,<NUM> are connected to the outer circumference of the first tube section <NUM> and second tube section <NUM> using a connection <NUM>, <NUM>' which can be a weld, adhesives, solder or other suitable connection. The latch mounting surface <NUM> is then used to connect components of a latch (not shown) to the metal hybrid reinforcement <NUM>. The area of the latch mounting surface <NUM> as shown can vary in size and have a surface area that is wider than the width of the first tube section <NUM> and second tube section <NUM>.

The metal hybrid reinforcement <NUM> further includes a first ball stud section <NUM> with a first end <NUM> and a second end <NUM> and a second ball stud section <NUM>' with a first end <NUM>' and second end <NUM>'. The first end <NUM> of the first ball stud section <NUM> is connected to the first end <NUM> of the first tube section <NUM>. The first end <NUM>' of the second ball stud section <NUM>' is connected to the first end <NUM> of the second tube section <NUM>. Both the first ball stud section <NUM> and the second ball stud section <NUM>' have a U-shaped cross-section with a first leg <NUM> and second leg <NUM> that connects to the outer circumference of the respective first tube section <NUM> or the second tube section <NUM> using a connection <NUM>, <NUM>' that is a weld, adhesives, solder, or other suitable connection. The first ball stud section <NUM> and the second ball stud section <NUM>' include a ball joint mounting surface <NUM>, <NUM>' that is used to connect a ball <NUM>, <NUM>' that is part of a ball joint connected between the composite liftgate <NUM> and the vehicle.

Connected to the second end <NUM> of the first ball stud section <NUM> is a left corner section <NUM> and connected to the second <NUM>' of the first ball stud section <NUM>' is a right corner section <NUM>. Extending between the left corner section <NUM> and right corner section <NUM> is a hinge attachment section <NUM>. The hinge attachment section <NUM> has a first end <NUM> and a second end <NUM>. The first end <NUM> of the hinge attachment section <NUM> is connected to the left corner section <NUM> so that the left corner section <NUM> wraps around and is connected by welding or bonding to the hinge attachment section <NUM>. The second end <NUM> of the hinge attachment section <NUM> is connected to the right corner section <NUM> so that the right corner section <NUM> wraps around and is connected by welding or bonding to the hinge attachment section <NUM>. The hinge attachment section <NUM> has an attachment surface area <NUM> that is used to connect one or more hinges that pivotally connect the composite liftgate <NUM> to a vehicle. The left corner section <NUM> and right corner section <NUM> in a preferred embodiment are two pieces formed of a front left corner piece 49a, back left corner piece 49b, front right corner piece 51a, and back right corner piece 51b that are connected together about the respective ends of the hinge attachment section <NUM>, first ball stud section <NUM> and second ball stud section <NUM>.

The composite liftgate <NUM> is completed by connection of an outer panel <NUM> connected to the inner panel <NUM>. The metal hybrid reinforcement <NUM> is positioned between the inner panel <NUM> and the outer panel <NUM>. The outer panel <NUM> forms the exterior show surface of the composite liftgate <NUM> and can be a single piece or it can be multiple pieces depending on the needs of a particular application. Additionally, there is a window <NUM> that is formed of plastic or glass that is connected to either the inner panel, <NUM> or the outer panel <NUM>. The window <NUM> is an optional feature since some vehicles do not have a rear window. Additionally, the composite liftgate <NUM> optionally further includes inner trim piece <NUM>, <NUM> that are shown as two pieces, however, a greater or lesser number of inner trim pieces can be used. The inner trin pieces <NUM>, <NUM> form the inside surface of the composite liftgate <NUM> that is visible from inside the passenger compartment of the vehicle. The metal hybrid reinforcement <NUM> once fully assembled has a circular shape that adds strength to the composite liftgate <NUM>, while also permitting several other structures such as hinges. ball joints and latch mechanisms to be attached.

Referring now to <FIG> are two embodiments of a vehicle door wherein like numbers differing by <NUM> are like components in the embodiments, with <FIG> showing a non-claimed embodiment. The vehicle door 110a, 110b, 210a, 210b that is a swing door having a first vehicle door 110a, 210a and second vehicle door 110b, 210b that are left and right side doors that meet together when in the closed position. The vehicle door 110a, 110b, 210a, 210b includes a left side door (see vehicle door 110b, 210b) and right side door (see vehicle door 110a, 210a), which can be arranged in a different orientation such as top and bottom or one side can be larger than the other. The vehicle door 110b, 110b, 210a, 210b each include a frame member 112a, 112b, 212a, 212b respectively, which is an internal tubular frame for providing attachment of hinges 114a, 114b, 214a, 214b and attachment surfaces 116a, 116b, 216a, 216b, 216c, 216d for connecting latches to the frame 112a, 112b, 212a, 212b.

Each vehicle door 110a, 110b, 210a, 210b further includes at least one inner panel 118a, 118b, 218a, 218b and outer panel 120a, 120b, 220a, 220b for attaching respectively to the frame 112a, 112b, 212a, 212b. Frame members 112a, 212a, inner panel 118a, 218a and outer panel 120a, 220a are respective mirror images of frame members 112b, 212b, inner panel 118b, 218b and outer panel 120b, 220b. The outer panel 120a, 120b in <FIG> includes multiple outer panels 121a, 121b, 121c, 121d, while the outer panel 220a 220b includes multiple outer panels 221a, 221b, 221c, 221d; however, it is within the scope of the invention for the multiple outer panels in both embodiments a lesser or greater number of panels depending on the needs of particular application. Multiple inner panels are also within the scope of the invention. In one embodiment the inner panels <NUM>, 18a, <NUM> and 118a are connected to the respective frame 12a, 12b, 112a, 112b by adhesives, fastener or the like and the outer panels 20a, 20b, 20c, 20d, 120a, 120b, 120c, 120d are connected to the inner panels.

Each of the frame members 112a, 112b, 212a, 212b the frame includes a first leg 122a, 122b, 222a, 222b, a middle connection leg 124a, 124b, 224a, 224b and a second leg 126a, 126b, 226a, 226b for forming a "C" shaped or "U" shaped frame member. The first leg 122a, 122b, 222a, 222b and second leg 126a, 126b, 226a, 226b have terminal outer ends 128a, 128b, 130a, 130b, 228a, 228b, 230a, 230b. Typically, these are extruded or other tubular members and are made out of aluminum or steel which allows welding attachment of hardpoints for hinges and latches. The tubes are typically bent but could be pieces welded together to from a "C" or "U" shape. With respect to the embodiment in <FIG> there is provided an additional reinforcement member 232a, 232b, referred to as a first reinforcement member and a second reinforcement member. Each reinforcement member 232a, 232b has an upper end 233a, 233b and a lower end 235a, 235b that are connected respectively to the terminal ends 228a, 228b, 230a, 230b to provide additional strength and rigidity if needed. Referring also to <FIG> and <FIG> the upper end 233a, 233b of the reinforcement 232a, 232b and terminal end 228a, 228b of second leg 226a, 226b are each connected to a respective an upper bracket 236a, 236b that also includes one of the attachment surfaces 216a, 216b. The lower end 235a, 235b of the reinforcement 232a, 232b and terminal end 230a, 230b of first leg 222a, 222b are each connected to a respective a lower bracket 238a, 238b that also includes one of the attachment surfaces 216c, 216d. The upper bracket 236a, 236b and lower bracket 238a, 238b provide the attachment surfaces 216a-d for attaching latches, locks and other features. The upper bracket 236a, 236b and lower bracket 238a, 238b also help reduce assembly complexity because they the reinforcements 232a, 232b and the tubular frame 212a, 212b will be connected with less bends.

When the reinforcements 238a, 238b are connected with the respective first leg 222a, 222b and second leg 226a, 226b the tubular frame 212a, 212b has an "O" profile. The reinforcement members are typically "L" shaped stampings and are formed of one or multiple pieces depending on the requirements of the particular door. If multiple pieces are used, they are connected together by welding, adhesives fasteners or other ways of joining the pieces. This reinforcement member could also include other cross-sectional shapes such as a tube or the like. The reinforcement member 232a, 232b is has a contoured portion 231a, 231b that contours to the respective inner panel 218a, 218b or outer panel 220a, 220b at a spoiler 234a, 234b area of the outer panel. This provides an even more robust structure if it is needed.

Claim 1:
A vehicle door (210a, 210b) comprising:
a first vehicle door (210a) having a tubular frame (212a) for providing attachment of hinges (214a) and attachment surfaces (216a, 216c) for connecting latches to the frame (212a) and an inner panel (218a) and an outer panel (220a) attached to the tubular frame (212a), and
a second vehicle door (210b) for meeting the first vehicle door (210a), the second vehicle door (210b) includes a tubular frame (212b) for providing attachment of hinges (214b) and attachment surfaces (216b, 216d) for connecting latches to the frame (212b) and an inner panel ( 218b) and an outer panel ( 220b) attached to the tubular frame (212b), such that the tubular frame (212b) is positioned between the inner panel (218b) and the outer panel (220b) internally within the vehicle door (210b)
wherein the tubular frame (212a) of the first vehicle door (210a) and the tubular frame (212b) of the second vehicle door (210b) both include a first leg (222a, 222b), a second leg (226a, 226b) and a middle connection leg (224a, 224b) for forming a "C" shape,
wherein the first leg (222a) and the second leg (226a) of the tubular frame (212a) of the first vehicle door (210a) each have a terminal end (228a, 230a) and the first leg (222b) and the second leg (226b) of the tubular frame (212b) of the second vehicle door (210b) each have a terminal end (228b, 230b);
a first reinforcement member (232a) having an upper end (233a) and a lower end (235a) connected to the tubular frame (212a) of the first vehicle door (210a) between the terminal end (230a) of the first leg (222a) and the terminal end (228a) of the second leg (226a), and
a second reinforcement member (232b) having an upper end (233b) and a lower end (235b) connected to the tubular frame (212b) of the second vehicle door (210b) between the terminal end (230b) of the first leg (222b) and the terminal end (228b) of the second leg (226b);
characterised in that the upper end (233a, 233b) of the reinforcement (232a, 232b) and terminal end (228a, 228b) of second leg (226a, 226b) are each connected to a respective upper bracket (236a, 236b) that also includes one of the attachment surfaces (216a, 216b), and the lower end (235a, 235b) of the reinforcement (232a, 232b) and terminal end (230a, 230b) of first leg (222a, 222b) are each connected to a respective a lower bracket (238a, 238b) that also includes one of the attachment surfaces (216c, 216d).