Patent Application
20140049033
This disclosure relates to vehicle frame components that are comprised of composite materials. Vehicle frame component structures are disclosed that address the relative lack of the compressive strength of composites compared to conventional metal materials used in vehicle frames. One desirable frame structure is a box frame rail structure that is comprised of composite materials and that has an enhanced capacity to accommodate compressive loads. In addition, the disclosed box frame rail structures provide protective routing options for wiring and pneumatic plumbing.
The foregoing and other objects, features, and advantages of the invention will become more apparent from the following detailed description, which proceeds with reference to the accompanying figures.
Described herein are embodiments of a composite box frame for a vehicle. The following description is exemplary in nature and is not intended to limit the scope, applicability, or configuration of the invention in any way. Various changes to the described embodiments may be made in the function and arrangement of the elements described herein without departing from the scope of the invention.
The vehicle frame 2 shown in
Each outside rail section 4 can comprise an outer wall such as a vertically oriented outer side wall 20, a transverse upper wall such as a horizontally oriented top wall 22 extending inwardly from a top edge portion of the side wall 20, a transverse bottom wall such as a horizontally oriented bottom wall 24 extending inwardly from a bottom edge portion of the side wall 20, a top flange 26 extending upwardly from an inner edge portion of the top wall 22, and a bottom flange portion 28 extending downwardly from an inner edge portion of the bottom wall 24. The outside rail sections 4 can thus have a “hat” shaped cross-section. That is, the outside rail sections 4 can be described as generally U-shaped in cross section with a base and first and second leg portions with diverging distal end flange portions that are spaced from the base. Similarly, each frame rail 3 can further comprise an inner rail section 6 joined to the outer rail section 4. The inner rail section can comprise an upright inner wall such as a vertically oriented side wall 30 spaced from wall 20, a transverse upper wall such as a horizontally oriented top wall 32 extending inwardly from a top edge portion of the side wall 30, a transverse lower wall such as a horizontally oriented bottom wall 34 extending inwardly from a bottom edge portion of the side wall 30, a top flange portion 36 extending upwardly from an inner edge portion of the top wall 32, and a bottom flange portion 38 extending downwardly from an inner edge portion of the bottom wall 34. The inner rail sections 6 can have a shallower “hat” shaped cross-section compared to the outside rail sections 4. That is, the inner rail sections 6 can also be described as U-shaped in cross-section with a base and first and second leg portions with diverging distal end flange portions spaced from the base. The leg portions of the inner rail section are desirably shorter than the leg portions of the outer rail section so that a substantially enclosed box is provided between the outer and inner rail sections.
The inside rail sections 6 can be nested within the outside rail sections 4, as shown in
The frame 2 can comprise one or more, and desirably plural spaced apart crossmembers 8 that couple the box frame rails 3 together at different positions along the longitudinal length of the frame. Each crossmember 8 can comprise a top wall 40, two side walls 42 extending downwardly from the respective side edge portions of the top wall 40, and two bottom projections such as flanges 44 extending away from bottom edge portions of the side walls 42. The top and bottom flanges can be horizontal and the side wall flanges 42 can be vertical. In some embodiments, one or more of the crossmembers 8 can be oriented upside down from the orientation shown, such that the top wall 40 is at the bottom and the bottom flanges 44 are at the top. The crossmember 8 can thus also have a “hat” or U-shaped cross-section, similar to the shape of outside and inside rails 4, 6, which can provide increase torsional rigidity in the crossmember.
One end of each of the crossmembers 8 can be coupled to one of the frame rails 3 and the other end of each of the crossmembers 8 can be coupled to the other frame rails 3, as shown in
End surfaces of the crossmember 8 can also be bonded or otherwise coupled to inner surfaces of the side walls 30 of the inside rail section 6. Brackets 12 can be used to couple the crossmembers 8 to the inside rail sections 6. The brackets 12 can comprise L-shaped or angle brackets comprising a base flange portion 48 and of a projecting flange portion 46 that extends away from the base flange portion. In the illustrated example, flanges 46, 48 are orthogonal to one another. Two of the brackets 12 can be used to couple an end of the crossmember 8 to the inner rail section 6, with one bracket 12 coupling each side wall 42 to the inner rail section 6. The flanges 46 of the bracket 12 can be bonded or otherwise coupled to the side walls 42 of the crossmember 8 and the side flanges 48 of the bracket 12 can be bonded or otherwise joined to the side walls 30 of the inner rails 6, thereby coupling the end crossmember 8 to the box sections 3. In addition, upper edge surfaces of the brackets 12 can be bonded or otherwise coupled to lower surfaces of the top walls 32 of the inner rail sections 6 and/or lower edge surfaces of the brackets 12 can be bonded or otherwise coupled to upper surfaces of the bottom walls 34 of the inner rails 6. In other embodiments, there can be spaces between the upper ends of the brackets 12 and the top walls 32 of the inner rail sections 6 and/or spaces between the bottom ends of the brackets 12 and the bottom walls 34 of the inner rail sections 6. Each end of the cross-members can be joined in the same manner by respective brackets to the proximate frame rail. The brackets 12 further provide increased strength in the high-stress areas where the crossmembers 8 are joined to the box sections 3.
A plurality of supports 10, which can be comprised of composite material, can be positioned within the internal spaces of the frame rails 3 to provide increased structural support to the frame rails where they are coupled to crossmembers 8. The supports 10 make the box sections of the frame rails 3 more resistant to crushing under compressive loads when other components are bolted or otherwise attached to the box sections. The supports 10 can also support the inserts 14. The supports 10 can comprise first and second support portions, such as shown in
The openings formed by adjoining pairs of the cavities 70 can be configured to surround and retain the inserts 14. The inserts 14 can comprise or consist of strong, durable materials, such as one or more of metal, composite, or polymer materials such as thermoset materials, as well as combinations thereof. In some embodiments, the inserts 14 can be made of a material that is stronger than the material of the supports 10 to provide added strength locally. The inserts can comprise an outer end portion 50, an inner end portion 52, and an intermediate portion 54. The intermediate portion 54 can comprise corrugations, ribs, or other features 56 that engage, such as mate or fit with, corresponding features in the cavities 70 to retain the inserts 14 in position against movement relative to the associated support, such as axial inward or outward movement relative to the associated support. In addition, the inner and outer end portions 50, 52 of the inserts 14 can have a greater diameter than the intermediate portion 56 to further restrict movement of the inserts 14 relative to the supports 70. The inserts 14 can be bonded or secured to the cavities 70. The corrugated or featured shape of the intermediate portion 54 provides an increased bonding surface area.
The inserts 14 desirably can have a generally cylindrical shape with a circular cross-section, as in the illustrated embodiment, but can have various other cross-sectional shapes in other embodiments, such as ovular, star-shaped, rectangular, triangular, or other non-circular cross-sectional shapes. The cavities 70 of the support portions can have a shape that matches the shape of the inserts 14.
The frame 2 can further comprise aligned holes in the various components through which the inserts 14 extend. For example, the outside rail sections 4 can comprise holes 80 in the side walls 20, the inside rail sections 6 can comprise holes 82 in the side walls 30, and the brackets 12 can comprise holes 84 in the side flanges 48. The holes 80, 82, and 84 can be formed with various processes, such as drilling or during manufacture of the frame rail sections. The holes 80, 82, 84 can be aligned with the cavities 70 in the supports 10 such that the inserts 14 can extend through the holes 80, 82, 84 as well as the supports 10. The outer end portions 50 of the inserts 14 can extend through the holes 80 in the outer rail 4. The outer end portions 50 can be flush with the outer surface of the side wall 20 of the outside rail 4. The inner end portions 52 can extend through the holes 82 in the inside rails 6 and through the holes 84 in the brackets 12. The inside end portions 52 can be flush with the inner surfaces of the side flanges 48 of the brackets 12.
The inserts 14 can further comprise an internal axially extending opening 58 extending entirely through the insert from the outer end portion 50 to the inner end portion 52. In this case, the inserts in effect comprise a tube that can be of metal. The internal openings 58 can serve various purposes. For example, the internal openings 58 can be threaded and serve as bolt holes, such as for attaching other components to the frame 2. The internal openings 58 can also serve as conduits for other objects to pass laterally through the box sections 3.
In some embodiments, bolts or other fasteners can be positioned through the internal openings 58 to clamp the brackets 12, inside rail sections 6, supports 10, and outside rail sections 4 together, either permanently or temporarily, such as until bonding together of the frame components is complete. As an example of bonding, an adhesive can be used to accomplish the bonding, less desirably, welding or bolting can be used.
The supports 10 and inserts 14 increase the strength of the frame rails 3 in bending, compression and torsion. The aligned combination of the crossmember 8 with the supports 10 and inserts 14 can support high lateral compressive loads on the frame.
With the possible exception of the inserts 14, which are desirably made of metal, the other components of the frame 2 can all be comprised of or consist entirely of composite materials, making the frame 2 lighter in weight compared to traditional metal frames. The composites used in the frame 2 can comprise any strong, lightweight composite or plurality of composites, such as fiber reinforced polymer composites. Examples of composite components include various fibers, resins, strengtheners, and other additives. Exemplary fibers include carbon fibers, glass fibers, aromatic polyamide fibers, such as Kevlar, and natural fibers, such as lignocellulosic fibers. Exemplary resins include phenolic resins, epoxies, polyesters, vinyl esters, polyetherketones, polyehterimides, polyethersulphone, high density polyethylenes, polycarbonates, acrylonitrile-butadiene-styrenes, polypropylene, nylon, and other thermoplastic and/or thermosetting polymers.
Several components of the frame 2, including the outside rail sections 4, inside rail sections 6, crossmembers 8, and brackets 12, can be manufactured using pultrusion processes, such as processes wherein unidirectional tows, woven mats, and/or other uncured composite materials are laid-up on a mandrel and pulled through a curing apparatus to form an elongated composite member having a generally constant cross-section. A more detailed description of exemplary fiber reinforced polymer materials and of exemplary pultrusion and related process, which can be used to manufacture components of the frame 2, can be found in U.S. Patent Application Publication No. US-2011-0204611-A1, entitled “Fiber Reinforced Polymer Frame Rail,” which was filed on Feb. 17, 2011, and which is herein incorporated by reference in its entirety.
For purposes of this description, certain aspects, advantages, and novel features of the embodiments of this disclosure are described herein. The disclosed embodiments should not be construed as limiting in any way. Instead, the present disclosure is directed toward all novel and nonobvious features and aspects of the various disclosed embodiments, alone and in various combinations and sub-combinations with one another.
As used herein, including in the claims, the terms “left”, “right”, “front”, “rear”, “top” and “bottom” refer to conventional portions of a vehicle in which the described box frame is configured to be incorporated, from the perspective of a driver of the vehicle. Thus, the left side is the driver's side in the United States, the right side is the passenger's side in the United States, the bottom is the portion of the vehicle closest to the ground, the front end is the leading end of the vehicle when the vehicle is traveling forward and the rear end is the leading end when the vehicle is traveling in reverse. The term “frontward” means toward the front and the term “rearward” means toward the rear. The term “upper” means toward the top and term “lower” means toward the bottom. Similarly, the terms “inner,” “inside” and “inwardly” mean toward a longitudinally extending vertical center plane of the vehicle that divides the vehicle into left and right halves, and the terms “outer,” “outside” and “outwardly” mean away from the center plane and toward the left or right side of the vehicle.
As used herein, the terms “a”, “an” and “at least one” encompass one or more of the specified element. That is, if two of a particular element are present, one of these elements is also present and thus “an” element is present. The terms “a plurality of” and “plural” mean two or more of the specified element.
As used herein, the term “and/or” used between the last two of a list of elements means any one or more of the listed elements. For example, the phrase “A, B, and/or C” means “A,” “B,” “C,” “A and B,” “A and C,” “B and C” or “A, B and C.”
As used herein, the term “coupled” generally means physically coupled or linked and does not exclude the presence of intermediate elements between the coupled items absent specific contrary language.
In view of the many possible embodiments to which the principles disclosed herein may be applied, it should be recognized that the illustrated embodiments are only preferred examples and should not be taken as limiting the scope of the invention. Rather, the scope of the invention is defined by the following claims. We therefore claim as our invention all that comes within the scope of these claims.
