Systems and methods of manufacturing a chassis

Abstract

A method of manufacturing a chassis includes casting a first frame member and casting a second frame member. The first frame member and the second frame member are fabricated from a nonferrous metal. The method further includes fastening the first frame member to the second frame member with a fastener. The fastener is fabricated from a different material than the nonferrous metal.

Description

SYSTEMS AND METHODS OF MANUFACTURING A CHASSISCROSS-REFERENCE TO RELATED PATENT APPLICATIONS

[0001] This application claims the benefit of and priority to U.S. Provisional Patent Application No. 63 / 466,077, filed on May 12, 2023, which is incorporated herein by reference in its entirety.BACKGROUND

[0002] A chassis or frame structurally supports various components (e.g., axles, operator platforms, powertrain, drivetrain, etc.) on a vehicle, equipment, or chore product.SUMMARY

[0003] At least one embodiment relates to a method of manufacturing a chassis. The method includes casting a first frame member and casting a second frame member. The first frame member and the second frame member are fabricated from a nonferrous metal. The method further includes fastening the first frame member to the second frame member with a fastener. The fastener is fabricated from a different material than the nonferrous metal.

[0004] Another embodiment relates to a method of manufacturing a chassis. The method includes casting a first frame member having a tapered protrusion, casting a second frame member having a tapered bore, and inserting the tapered protrusion into the tapered bore and applying a holding force to the second frame member to form an initial coupling between the first frame member and the second frame member at an interface between the tapered protrusion and the tapered bore, and fastening the first frame member to the second frame member by applying a locking force to a threaded fastener so that yielding occurs at the interface between the tapered protrusion and the tapered bore.

[0005] Another embodiment relates to a method of manufacturing a chassis. The method includes forming a plurality of side frame members via a die casting process, forming a cross frame member via the die casting process, and fastening the plurality of side frame members to the cross frame member using a weldless assembly of fasteners.

[0006] Another embodiment relates to a chassis that includes a first frame member and a second frame member. The first frame member and the second frame member are fabricated from a nonferrous metal. The first frame member is fastened to the second frame member by a threaded fastener. The threaded fastener is fabricated from a steel material.

[0007] Another embodiment relates to a chassis that includes a right-side frame member, a left-side frame member, and a cross frame member extending laterally between the right-side frame member and the left-side frame member. The right-side frame member and the left-side frame member are coupled to the cross frame member using a weldless assembly of fasteners.

[0008] Another embodiment relates to a chassis that includes a first frame member having a tapered protrusion and a second frame member having a tapered bore. When the tapered protrusion is inserted into the tapered bore and a holding force is applied to the second frame member, an interface between the tapered protrusion and the tapered bore is configured to form an initial coupling between the first frame member and the second frame member.

[0009] Another embodiment relates to a chassis that includes a plurality of side frame members and a plurality of cross frame members. Each of the plurality of cross frame members extends laterally relative to the plurality of side frame members. Each of the plurality of side frame members and the plurality of cross frame members defines a casting part projected area that is less than or equal to 150 in2.

[0010] Another embodiment relates to a chassis that includes a frame member having a first side and a second side. The first side includes a first lattice structure having a first plurality of interconnected segments, and the second side includes a second lattice structure having a second plurality of interconnected segments. The first lattice structure and the second lattice structure are asymmetrical.

[0011] This summary is illustrative only and is not intended to be in any way limiting. Other aspects, inventive features, and advantages of the devices or processes described herein will become apparent in the detailed description set forth herein, taken in conjunction with the accompanying figures, wherein like reference numerals refer to like elements.BRIEF DESCRIPTION OF THE FIGURES

[0012] The disclosure will become more fully understood from the following detailed description, taken in conjunction with the accompanying figures, wherein like reference numerals refer to like elements, in which:

[0013] FIG. 1 is top, front, right perspective view of a chassis, according to an exemplary embodiment;

[0014] FIG. 2 is a top view of the chassis of FIG. 1;

[0015] FIG. 3 is a bottom view of the chassis of FIG. 1;

[0016] FIG. 4 is a left side view of the chassis of FIG. 1;

[0017] FIG. 5 is a right side view of the chassis of FIG. 1;

[0018] FIG. 6 is a front view of the chassis of FIG. 1;

[0019] FIG. 7 is a rear view of the chassis of FIG. 1;

[0020] FIG. 8 is an exploded top, front, right perspective view of the chassis of FIG. 1;

[0021] FIG. 9 is a top, front, right perspective view of a rear cross frame member of the chassis of FIG. 1;

[0022] FIG. 10 is a bottom, rear, left perspective view of the rear cross frame member of FIG. 9;

[0023] FIG. 11 is a perspective view of the rear cross frame member of FIG. 9 showing a casting part projected area of the rear cross frame member;

[0024] FIG. 12 is a top, front, right perspective view of a middle cross frame member of the chassis of FIG. 1;

[0025] FIG. 13 is a bottom, rear, left perspective view of the middle cross frame member of FIG. 12;

[0026] FIG. 14 is a perspective view of the middle cross frame member of FIG. 12 showing a casting part projected area of the middle cross frame member;

[0027] FIG. 15 is a top, front, right perspective view of a front corner cross frame member of the chassis of FIG. 1;

[0028] FIG. 16 is a bottom, rear, left perspective view of the front corner cross frame member of FIG. 15;

[0029] FIG. 17 is a perspective view of the front corner cross frame member of FIG. 15 showing a casting part projected area of the front corner cross frame member;

[0030] FIG. 18 is a top, front, right perspective view of a front cross frame member of the chassis of FIG. 1;

[0031] FIG. 19 is a bottom, rear, left perspective view of the front cross frame member of FIG. 18;

[0032] FIG. 20 is a perspective view of the front cross frame member of FIG. 18 showing a casting part projected area of the front cross frame member;

[0033] FIG. 21 is a top, front, right perspective view of a rear side frame member of the chassis of FIG. 1;

[0034] FIG. 22 is a bottom, rear, left perspective view of the rear side frame member of FIG. 21;

[0035] FIG. 23 is a perspective view of the rear side frame member of FIG. 21 showing a casting part projected area of the rear side frame member;

[0036] FIG. 24 is a top, front, right perspective view of a middle side frame member of the chassis of FIG. 1;

[0037] FIG. 25 is a bottom, rear, left perspective view of the middle side frame member of FIG. 24;

[0038] FIG. 26 is a perspective view of the middle side frame member of FIG. 24 showing a casting part projected area of the middle side frame member;

[0039] FIG. 27 is a top, front, right perspective view of a front side frame member of the chassis of FIG. 1;

[0040] FIG. 28 is a bottom, rear, left perspective view of the front side frame member of FIG. 27;

[0041] FIG. 29 is a perspective view of the front side frame member of FIG. 27 showing a casting part projected area of the front side frame member;

[0042] FIG. 30 is an exploded top, front, right perspective view of a front side frame member, a middle side frame member, and a middle cross frame member of the chassis of FIG. 1;

[0043] FIG. 31 is an exploded top, rear, left perspective view of the front side frame member, the middle side frame member, and the middle cross frame member of FIG. 30;

[0044] FIG. 32 is a top, front, right perspective view of a tapered protrusion of the middle cross frame member of FIG. 30;

[0045] FIG. 33 is a front view of the tapered protrusion of FIG. 32;

[0046] FIG. 34 is a bottom, front, left perspective view of a tapered bore of the middle side frame member of FIG. 30;

[0047] FIG. 35 is a cross-sectional view of the tapered bore of FIG. 34 taken along line 35-35;

[0048] FIG. 36 is a cross-sectional view of the tapered protrusion of the middle cross frame member of FIG. 32 inserted within the tapered bore of the middle side frame member of FIG. 34;

[0049] FIG. 37 is a cross-sectional view of the tapered protrusion of the middle cross frame member of FIG. 32 inserted within the tapered bore of the middle side frame member of FIG. 34, a tapered protrusion of the middle side frame member of FIG. 34 inserted within a tapered bore of the front side frame member of FIG. 30, and a fastener;

[0050] FIG. 38 is a perspective view of a tapered protrusion including a plurality of ribs, according to some embodiments;

[0051] FIG. 39 is a flowchart outlining the steps in a method of manufacturing the chassis of FIG. 1 ;

[0052] FIG. 40 is a flowchart outlining the steps in the method of FIG. 39 for assembling the chassis of FIG. 1;

[0053] FIG. 41 is a perspective view of cross frame members of the chassis of FIG. 1 arranged on an assembly jig;

[0054] FIG. 42 is a perspective view of middle side frame members being installed on the rear and middle cross frame members arranged on the assembly jig of FIG. 41;

[0055] FIG. 43 is a perspective view of front side frame members being installed on the middle and front corner cross frame members, after installation of the middle side frame members in FIG. 42;

[0056] FIG. 44 is a perspective view of rear side frame members being installed on the rear cross frame member and a front cross frame member being installed on the front comer cross frame members, after installation of the front side frame members in FIG. 43;

[0057] FIG. 45 is a perspective view of a powertrain support tray being installed on the rear side frame members, after installation of the rear side frame members and front cross frame member in FIG. 44;

[0058] FIG. 46 is a side view of a powder coating process for the assembled chassis, after installation of the powertrain support tray in FIG. 45; and

[0059] FIG. 47 is a perspective view of a powertrain being installed on the powertrain support tray, after the powder coating process in FIG. 46.DETAILED DESCRIPTION

[0060] Before turning to the figures, which illustrate certain exemplary embodiments in detail, it should be understood that the present disclosure is not limited to the details or methodology set forth in the description or illustrated in the figures. It should also be understood that the terminology used herein is for the purpose of description only and should not be regarded as limiting.

[0061] The use herein of the term “axial” and variations thereof refers to a direction that extends generally along an axis of symmetry, a central axis, or an elongate direction of a particular component or system. For example, an axially-extending structure of a component may extend generally along a direction that is parallel to an axis of symmetry or an elongate direction of that component. Similarly, the use herein of the term “radial” and variations thereof refers to directionsthat are generally perpendicular to a corresponding axial direction. For example, a radially extending structure of a component may generally extend at least partly along a direction that is perpendicular to a longitudinal or central axis of that component. The use herein of the term “circumferential” and variations thereof refers to a direction that extends generally around a circumference or periphery of an object, around an axis of symmetry, around a central axis, or around an elongate direction of a particular component or system.

[0062] The present disclosure is directed to outdoor power equipment or chore products. A “chore product” as used herein refers to any type of equipment, machine, or vehicle that may be used to perform a chore (e.g., an outdoor chore, an indoor chore, lawn care, transportation, etc.). For example, a chore product may include a motor, an engine, a pump, an actuator, a compressor, and / or another device that is electrically-, mechanically-, or hydraulically-powered to operate some function of the chore product and facilitate performing a chore. In some embodiments, a chore is a task performed, either by a user or autonomously, at or near a household, a farm, an agricultural facility, a building, a sidewalk, a park, a parking lot, a forest, a field, and / or a lawn. In some embodiments, a chore product transports an operator and performs a chore. In some embodiments, a chore product autonomously operates to perform a chore without an operator being present on the chore product or physically / manually manipulating the chore product.

[0063] In some embodiments, the chassis described herein is implemented on a mower (e.g., a zero-turn radius (ZTR) mower). In some embodiments, the chassis may be configured as or the features thereof may be implemented on other electrified chore products or “light” electrified, motored, or hybrid vehicles, machines, or equipment, including outdoor power equipment, indoor power equipment, light vehicles, floor care devices, golf carts, lift trucks and other industrial vehicles, pavement surface preparation devices, recreational utility vehicles, industrial utility vehicles, lawn and garden equipment, and / or still other suitable vehicles, machines, or equipment. Outdoor power equipment or outdoor chore products may include lawn mowers, riding tractors, snow throwers, pressure washers, tillers, log splitters, walk-behind mowers, riding mowers, and turf equipment such as sod cutters, aerators, spreaders, sprayers, seeders, power rakes, and blowers. Outdoor power equipment or outdoor chore products may, for example, use one or more electric motors to drive an implement, such as a rotary blade of a lawn mower, a pump of a pressure washer, the auger of a snow thrower, the alternator of a generator, and / or a drivetrain of the outdoor power equipment. Indoor power equipment or indoor chore products may include floor sanders,floor buffers and polishers, vacuums, etc. Recreational utility vehicles may include all-terrain vehicles (“ATVs”), utility task vehicles (“UTVs”), etc. Industrial utility vehicles may include forklifts, aircraft tugs, aerial lifts such as scissor lifts, and boom lifts, etc.

[0064] A chassis or frame on a conventional chore product typically includes frame members that require fabrication or machining after being formed, and the frame members are typically joined by a welding process to assemble the chassis. For example, the frame members on a conventional chassis are often formed by tubular rails and beams that require time-consuming and specialized machining (e.g., milling, cutting to length, stamping, bending, etc.) prior to assembly. In addition to the required machining prior to assembly, the frame members on a conventional chassis are joined by a welding process. The welding processes limit the type of materials used in a conventional chassis, because it is difficult to weld dissimilar materials, and further requires a specialized workforce to assemble the chassis. Both the pre-assembly machining and specialized workforce increase the time and cost associated with manufacturing and assembling conventional chassis, and the welding process typically requires that conventional chassis are fabricated from steel, which increases weight.

[0065] The present disclosure provides systems and methods for a chassis that is formed by a casting processes (e.g., die casting) and is assembled in an as-cast state, which enables the chassis to be assembled without additional machining after the casting process. In general, the use herein of the term “as-cast state” or “as-cast” refers to the state of a component after it is cast in a die cast mold and a trim die has removed excess material from the cast component. That is, the casting of a component in a die cast mold and the use of a trim die to remove excess material are both defined herein as a casting process and the completion of both steps in the casting process defines the as- cast state or an as-cast component. The assembly of various frame members of the chassis in an as-cast state eliminates the required pre-assembly machining in conventional chassis, which reduces the cost and time associated with assembling the chassis when compared to a conventional chassis.

[0066] The use of a casting process to manufacture the frame members of the chassis also enables the frame members to be efficiently assembled. For example, the as-cast frame members allow dissimilar materials to be joined or fastened, unlike a welding process. In some embodiments, the frame members of the chassis are fabricated from a first material (e.g., anonferrous metal, such as aluminum or magnesium), and then fastened using a weldless assembly of fasteners that are fabricated from a second material (e.g., a ferrous metal, such as steel) that is different from the first material. The use of multiple or dissimilar materials in the chassis improves manufacturability by not limiting the frame members and the fasteners to a single material.

[0067] In addition, the weldless assembly of fasteners provide a more efficient installation process than welding on a conventional chassis. In some embodiments, for example, the weldless assembly of fasteners comprise a plurality of screws with self-tapping threads that are installed using hand tools (e.g., screw drivers, etc.). The ability to use hand tools when assembling the as- cast frame members significantly reduces the time and cost associated with assembling the chassis, and reduces the amount of scrap and material waste during assembly (e.g., welded components require a new component after an assembly mistake, while screws can be easily removed and reinstalled). The use of self-tapping screws further allows for the assembly of the as-cast frame members to be torque-controlled, which standardizes the assembly of the chassis and generates engineered joints at the interfaces between the frame members (e.g., the joints at the interfaces between the frame members are formed with a predetermined installation or holding force).

[0068] The use of a casting process to manufacture the frame members of the chassis further enables the frame members to include complex geometries and features that add both functionality and structural integrity to the frame members. In some embodiments, for example, at least one of the frame members is formed with a first lattice structure on a first side that defines a first pattern and a second lattice structure on an opposing second side that defines a second pattern. In some embodiments, the first lattice structure and the second lattice structure are asymmetrical, which provides particular areas along the frame member (e.g., areas with a lattice structure) with varied mechanical properties (e.g., bending moment of inertia, bending stiffness, mass / weight, etc.) and improves overall chassis performance.

[0069] In some embodiments, at least two of the frame members of the chassis include tapered features that are designed to self-lock (e.g., form an initial coupling that holds two components together without a fastener) between the two frame members after a holding force is applied to one of the frame members. The tapered features provide initial part placement, retention, and alignment without the use of fasteners via the application of the holding force (e.g., tapping with a mallet or hammer). In some embodiments, the tapered features include a tapered protrusionarranged on a first frame member and a tapered bore arranged on a second frame member. When the tapered protrusion is inserted within the tapered bore and a holding force is applied to one of the first frame member or the second frame members, an interference fit is formed at the interface between the tapered protrusion and the tapered bore that provides holding capabilities (e.g., an initial coupling is formed between the first frame member and the second frame member). With the initial coupling formed between the first frame member and the second frame member, an operator may temporarily move away from the assembly to access other components (e.g., the selftapping screw used to form the primary fastening between the first frame member and the second frame member) without the assembly moving or losing alignment. In addition, the tapered features enable two or more frame members to be stacked within a joint to be retained by a common fastener, which is not possible with conventional welded chassis.Chassis

[0070] Turning now to FIGS. 1-8, a chassis 100 is shown according to an exemplary embodiment of the present disclosure. In some embodiments, the chassis 100 is included on a ZTR mower, or any of the other chore products, equipment, or vehicles described herein. The chassis 100 is manufactured using a die casting process and assembled according to the systems and methods described herein. In general, the chassis 100 includes cross frame members, cross frame rails, or cross frame plates and side frame members, side frame rails, or side frame plates, with the cross frame members / rails / plates extending laterally between the side frame members / plates / rails. In some embodiments, this arrangement of the frame members / plates / rails may provide a ladder-style chassis.

[0071] In the illustrated embodiment, the chassis 100 includes a plurality of cross frame members 102 and a plurality of side frame members 104, each of which is formed or manufactured via a die casting process. Each of the plurality of cross frame members 102 and the plurality of side frame members 104 is fabricated from a nonferrous metal. In some embodiments, the nonferrous metal is aluminum. In some embodiments, the nonferrous metal is magnesium. In any case, the density of the material used to fabricate the cross frame members 102 and the side frame members 104 is less than the density of, for example, plain steel or carbon steel, which are commonly used to fabricate conventional chassis. The lower density material used in the die casting process for the cross frame members 102 and the side frame members 104 reduces theoverall weight of the chassis 100 when compared to conventional chassis. The lower weight of the chassis 100 may help to offset increased powertrain weight, for example, in electrified applications, where increased runtime requires larger or more battery packs and additional weight supported on the chassis 100.

[0072] Each of the plurality of cross frame members 102 is arranged laterally inwardly relative to the plurality of side frame members 104 and extends substantially along to a lateral direction 106 (e.g., vertically from the perspective of FIG. 2), which is perpendicular to a longitudinal plane 108 (see, e.g., FIG. 2) that extends along a centerline of the chassis 100. Each of the side frame members 104 extends substantially along to a longitudinal direction 110 (e.g., horizontally from the perspective of FIG. 2), which is parallel to the longitudinal plane 108. During assembly, the plurality of side frame members 104 are fastened to one or more of the plurality of cross frame members 102 using a weldless assembly of fasteners 112, as will be described herein.

[0073] In the illustrated embodiment, the plurality of cross frame members 102 includes a rear cross frame member 114, a middle cross frame member 116, a front-right-corner cross frame member 118, a front-left-corner cross frame member 120, and a front cross frame member 122. The chassis 100 defines various sections along its longitudinal length that may be defined, for example, with respect to one or more of the cross frame members 102. In some embodiments, the chassis 100 defines a rear section 124, a middle section 126, and a front section 128. The rear section 124 may be arranged rearward (e.g., to the left from the perspective of FIG. 2) of the rear cross frame member 114 along the longitudinal direction 110. The front section 128 may be arranged frontward (e.g., to the right from the perspective of FIG. 2) of the middle cross frame member 116 along the longitudinal direction 110, and the middle section 126 may be arranged longitudinally between the rear section 124 and the front section 128 (e.g., frontward of the rear cross frame member 114 and rearward of the middle cross frame member 116). It should be appreciated that the terms “rear,” “middle,” and “front” used herein with respect to the frame members 114, 116, 118, 120, 122, 130, 132, 134, 136, 138, 140 do not limit these elements to being solely arranged within a corresponding one of the rear section 124, the middle section 126, or the front section 128. Some of the frame members 114, 116, 118, 120, 122, 130, 132, 134, 136, 138, 140 may span one or more of the rear section 124, the middle section 126, or the front section 128, and the use of the terms “rear,” “middle,” and “front” may indicate the associated sectionwithin which a majority of the frame member 114, 116, 1 18, 120, 122, 130, 132, 134, 136, 138, 140 is arranged.

[0074] In the illustrated embodiment, the plurality of side frame members 104 includes a rightrear side frame member 130, a left-rear side frame member 132, a right-middle side frame member 134, a left-middle side frame member 136, a right-front side frame member 138, and a left-front side frame member 140. The chassis 100 defines a right side 142 and a left side 144, with the right-rear side frame member 130, the right-middle side frame member 134, the right-front side frame member 138, and the front-right-corner cross frame member 118 being arranged along the right side 142, and the left-rear side frame member 132, the left-middle side frame member 136, the left-front side frame member 140, and the front-1 eft-comer cross frame member 120 being arranged long the left side 144. In general, the chassis 100 is symmetric about the longitudinal plane 108. For example, the front-right-comer cross frame member 118 is symmetric to the front- left-comer cross frame member 120 about the longitudinal plane 108, the right-rear side frame member 130 is symmetric to the left-rear side frame member 132 about the longitudinal plane 108, and so on for the corresponding components arranged on opposing sides of the longitudinal plane 108.

[0075] In some embodiments, one or more auxiliary components are coupled to the chassis 100. For example, the plurality of cross frame members 102 and the plurality of side frame member 104 may form the core structure and assembly of the chassis 100, and depending on the particular chore product, equipment, or vehicle that the chassis 100 is integrated into, the number, type, and / or arrangement of auxiliary components may vary. In the illustrated embodiment, a footwell support bar 146, a pair of footwell support brackets 148, a pair of shock mount brackets 150, a plurality of control arm brackets 152, a pair of swing arm pivot brackets 154, and a powertrain support tray 156 are coupled to various locations on the chassis 100. For example, the footwell support bar 146 is coupled to the right-front side frame member 138 and the left-front side frame member 140, and extends laterally between the right-front side frame member 138 and the left-front side frame member 140. One of the footwell support brackets 148 is coupled to the front-right-corner cross frame member 118, and the other footwell support bracket 148 is coupled to the front-left-corner cross frame member 120. Similarly, one of the shock mount brackets 150 is coupled to the front-right-corner cross frame member 118, and the other shock mount bracket 150 is coupled to the front-left-corner cross frame member 120. In the illustrated embodiment,each of the front-right-corner cross frame member 118 and the front-left-comer cross frame member 120 includes two of the control arm brackets 152 coupled thereto. One of the swing arm pivot brackets 154 is arranged laterally outwardly from and coupled to the right-middle side frame member 134 and the right-front side frame member 138, and the other swing arm pivot bracket 154 is arranged laterally outwardly from and coupled to the left-middle side frame member 136 and the left-front side frame member 140. In the illustrated embodiment, the powertrain support tray 156 is coupled to the rear cross frame member 114, the right-rear side frame member 130, and the left-rear side frame member 132, and extends laterally between the right-rear side frame member 130 and the left-rear side frame member 132.Frame Members

[0076] With reference to FIGS. 9 and 10, the rear cross frame member 114 includes a right end plate 158, a left end plate 160, and a center rail 162 extending between the right end plate 158 and the left end plate 160. In general, the right end plate 158 and the left end plate 160 include coupling and fastening features that enable the rear cross frame member 114 to be initially coupled and then fastened to the right-rear side frame member 130, the left-rear side frame member 132, the right-middle side frame member 134, and the left-middle side frame member 136. The design and elements of the right end plate 158 are symmetric to the left end plate 160 about the longitudinal plane 108. Therefore, the description herein relating to the right end plate 158 symmetrically applies to the left end plate 160, with like elements being identified using similar reference numerals.

[0077] The right end plate 158 includes a plurality of fastening apertures or bores 164. Each of the fastening bores 164 is recessed into a locking face 166 of the right end plate 158. In the illustrated embodiment, the right end plate 158 includes four fastening bores 164, one being arranged adjacent to each of the four corners of the right end plate 158. As described herein, the frame members of the chassis 100 include tapered features that self-lock and enable an initial coupled to be formed between two or more components of the chassis 100. In some embodiments, the self-locking tapered features include a tapered protrusion 168 that is designed to fit within a tapered bore 170 and form an interference fit at an interface between the tapered protrusion 168 and the tapered bore 170 that provides holding capabilities without the use of a fastener. In the illustrated embodiment, the right end plate 158 includes a two of the tapered protrusions 168. Eachof the tapered protrusions 168 protrudes outwardly from the locking face 166 and is axially aligned with a corresponding one of the fastening bores 164 (e.g., the tapered protrusion 168 is arranged coaxially with a bore axis defined by the corresponding fastening bore 164). In the illustrated embodiment, the tapered protrusions 168 of the right end plate 158 are arranged in opposite corners of the right end plate 158. In some embodiments, the right end plate 158 may include more or less than two of the tapered protrusions 168.

[0078] The center rail 162 includes a front face 172, a rear face 174, and a plurality of generally hollow cavities 176 that are arranged in a grid-like pattern. The rear face 174 includes a plurality of fastening bores 178 that are each recessed into the rear face 174. Each of the hollow cavities 176 extends between the front face 172 and the rear face 174 and includes a cutout 180. The hollow cavities 176 are each framed by a combination of horizontally-extending plates 182 (e.g., horizontally-extending from the perspective of FIG. 9) and vertically-extending plates 184 (e.g., vertically-extending from the perspective of FIG. 9). In the illustrated embodiment, each of the fastening bores 178 is located at a corresponding vertex formed by the horizontally-extending plates 182 and the vertically-extending plates 184.

[0079] Turning to FIG. 11, a casting part projected area 186 of the rear cross frame member 114 is shown in cross-hatching. The use of the term “casting part projected area” herein represents the surface area of a component / part that is projected into a plane that is perpendicular or normal to a parting direction defined in a die casting process. In a die casting process, the parting direction is the direction that the molds are separated and in which an opening force is generated on the molds. The plane perpendicular to the parting direction, which the casting part projected area is projected into, therefore, captures the part projected area (not total projected area that often adds in the areas of the biscuit, overflow, gates, etc.) used in the calculation to determine the locking or holding force required to hold the molds together during the die casting process, and the corresponding size of the die casting machine (often in tonnage) required to apply the locking or holding force. In general, cutouts or apertures that extend completely through a part along a direction normal to the parting direction do not contribute to the casting part projected area. For example, the cutouts 180 remove at least some area from the casting part projected area 186 of the rear cross frame member 114. But the remaining surface area that is projected into the plane normal to the parting direction contributes to the casting part projected area.

[0080] In some embodiments, the casting part projected area 186 of the rear cross frame member 114 may be less than or equal to about 60 in2, or less than or equal to about 50 in2. In general, the plurality of cross frame members 102 (i.e., the rear cross frame member 114, the middle cross frame member 116, the front-right-comer cross frame member 118, the front-left- corner cross frame member 120, and the front cross frame member 122) and the plurality of side frame members 104 (i.e., the right-rear side frame member 130, the left-rear side frame member 132, the right-middle side frame member 134, the left-middle side frame member 136, the rightfront side frame member 138, and the left-front side frame member 140) each define a casting part projected area that may be less than or equal to about 150 square inches (in2), or less than or equal to about 140 in2, or less than or equal to about 130 in2. The use of a casting part projected area less than or equal to about 150 in2enables all the cross frame members 102 and the side frame members 104 to be manufactured on a common die casting machine (e.g., a machine with the same tonnage rating for holding or locking force) with at least one part cavity per mold (e.g., at least one part is made per casting).

[0081] With reference to FIGS. 12 and 13, the middle cross frame member 116 includes a right end plate 188, a left end plate 190, and a center rail 192 extending between the right end plate 188 and the left end plate 190. In general, the right end plate 188 and the left end plate 190 include coupling and fastening features that enable the middle cross frame member 116 to be initially coupled and then fastened to the right-middle side frame member 134, the left-middle side frame member 136, the right-front side frame member 138, and the left-front side frame member 140. The design and elements of the right end plate 188 are symmetric to the left end plate 190 about the longitudinal plane 108. Therefore, the description herein relating to the right end plate 188 symmetrically applies to the left end plate 190, with like elements being identified using similar reference numerals.

[0082] The right end plate 188 includes a plurality of fastening apertures or bores 194. Each of the fastening bores 194 is recessed into an locking face 196 of the right end plate 188. In the illustrated embodiment, the right end plate 188 includes eight fastening bores 194. In the illustrated embodiment, the right end plate 188 includes a two of the tapered protrusions 168. Each of the tapered protrusions 168 protrudes outwardly from the locking face 196 and is axially aligned with a corresponding one of the fastening bores 194 (e.g., the tapered protrusion 168 is arranged coaxially with a bore axis defined by the corresponding fastening bore 194). In someembodiments, the right end plate 188 may include more or less than two of the tapered protrusions 168.

[0083] The center rail 192 includes a front face 198, a rear face 200, and a plurality of generally hollow cavities 202 that are arranged in a grid-like pattern. Each of the hollow cavities 202 extends between the front face 198 and the rear face 200 and includes a cutout 204. The hollow cavities 202 are each framed by a combination of horizontally-extending plates 206 (e.g., horizontallyextending from the perspective of FIG. 12) and vertically-extending plates 208 (e.g., vertically- extending from the perspective of FIG. 12).

[0084] Turning to FIG. 14, a casting part projected area 210 of the middle cross frame member 116 is shown in cross-hatching. In some embodiments, the casting part projected area 210 of the middle cross frame member 116 is less than or equal to about 100 in2, or less than or equal to about 90 in2.

[0085] With reference to FIGS. 15 and 16, the front-right-corner cross frame member 118 is shown. The design and elements of the front-right-corner cross frame member 118 are symmetric to the front-left-corner cross frame member 120 about the longitudinal plane 108. Therefore, the description herein relating to the front-right-corner cross frame member 118 symmetrically applies to the front-left-corner cross frame member 120, with like elements being identified using similar reference numerals. The front-right-corner cross frame member 118 includes a first locking face 212, a second locking face 214, and a mounting plate 216 arranged between the first locking face 212 and the second locking face 214. The second locking face 214 is arranged rearward of the first locking face 212. In general, the first locking face 212 includes coupling and fastening features that enable the front cross frame member 122 to be initially coupled and then fastened to the front-right-corner cross frame member 118, and the second locking face 214 includes coupling and fastening features that enable the right-front side frame member 138 to be initially coupled and then fastened to the front-right-comer cross frame member 118.

[0086] In the illustrated embodiment, the first locking face 212 includes a plurality of fastening bores 218. Each of the fastening bores 218 is recessed into the first locking face 212. In the illustrated embodiments, the first locking face 212 includes two of the tapered protrusions 168. Each of the tapered protrusions 168 protrudes outwardly from the first locking face 212 and is axially aligned with a corresponding one of the fastening bores 218 (e.g., the tapered protrusion168 is arranged coaxially with a bore axis defined by the corresponding fastening bore 218). In some embodiments, the first locking face 212 may include more or less than two of the tapered protrusions 168.

[0087] In the illustrated embodiment, the second locking face 214 includes a plurality of fastening bores 220. Each of the fastening bores 220 is recessed into the second locking face 214. In the illustrated embodiments, the second locking face 214 includes two of the tapered protrusions 168. Each of the tapered protrusions 168 protrudes outwardly from the second locking face 214 and is axially aligned with a corresponding one of the fastening bores 220 (e.g., the tapered protrusion 168 is arranged coaxially with a bore axis defined by the corresponding fastening bore 220). In some embodiments, the second locking face 214 may include more or less than two of the tapered protrusions 168.

[0088] In some embodiments, the mounting plate 216 may include one or more fastening bores that facilitate coupling one or more of the auxiliary components to the front-right-corner cross frame member 118 (e.g., the of shock mount brackets 150 and / or the control arm brackets 152). In some embodiments, the footwell support brackets 148 may be coupled to the front-right-corner cross frame member 118 on an opposite side of the first locking face 212.

[0089] Turning to FIG. 17, a casting part projected area 222 of the front-right-comer cross frame member 118 is shown in cross-hatching. In some embodiments, the casting part projected area 222 of the front-right-corner cross frame member 118 is less than or equal to about 80 in2, or less than or equal to about 70 in2. As illustrated in FIG. 17, although at least some of the fastening bores (e.g., the fastening bores 218, 220) extend through the front-right-corner cross frame member 118, the relative orientation between the fastening bores to the projected plane does not define any through holes (e.g., an imaginary line extending along any point in the fastening bores and normal to the projected plane passes through solid material).

[0090] With reference to FIGS. 18 and 19, the front cross frame member 122 includes a first locking face 224 and a second locking face 226. In general, the first locking face 224 includes coupling and fastening features that enable the front cross frame member 122 to be initially coupled and then fastened to the front-right-corner cross frame member 118, and the second locking face 226 includes coupling and fastening features that enable the front cross frame member 122 to be initially coupled and then fastened to the front-left-corner cross frame member 120. Inthe illustrated embodiment, the first locking face 224 is laterally separated from the second locking face 226. The first locking face 224 includes a plurality of fastening bores 228 and the second locking face 226 includes a plurality of fastening bores 230. In the illustrated embodiment, the first locking face 224 includes two of the tapered bores 170, and the second locking face 226 includes two of the tapered bores 170. Each of the tapered bores 170 in the first locking face 224 is recessed into the first locking face 224 and is axially aligned with a corresponding one of the fastening bores 228 (e.g., the tapered bore 170 is arranged coaxially with a bore axis defined by the corresponding fastening bore 228). Each of the tapered bores 170 in the second locking face 226 is recessed into the second locking face 226 and is axially aligned with a corresponding one of the fastening bores 230 (e.g., the tapered bore 170 is arranged coaxially with a bore axis defined by the corresponding fastening bore 230).

[0091] Turning to FIG. 20, a casting part projected area 232 of the front cross frame member 122 is shown in cross-hatching. In some embodiments, the casting part projected area 232 of the front cross frame member 122 is less than or equal to about 50 in2, or less than or equal to about 40 in2.

[0092] With reference to FIGS. 21 and 22, the right-rear side frame member 130 is shown. The design and elements of the right-rear side frame member 130 are symmetric to the left-rear side frame member 132 about the longitudinal plane 108. Therefore, the description herein relating to the right-rear side frame member 130 symmetrically applies to the left-rear side frame member 132, with like elements being identified using similar reference numerals. The right-rear side frame member 130 defines a first or inner-facing side 234, a second or outer-facing side 236, a longitudinally-front end 238, a longitudinally-rear end 240, a top end 241, and a bottom end 243. In the illustrated embodiment, the right-rear side frame member 130 includes a locking face 242 arranged on the first or inner-facing side 234 in a location adjacent to the longitudinally-front end 238.

[0093] In general, the right-rear side frame member 130 includes coupling and fastening features that enable the right-rear side frame member 130 to be initially coupled to the right-middle side frame member 134 and then fastened to both the right-middle side frame member 134 and the rear cross frame member 114. In the illustrated embodiment, the right-rear side frame member 130 includes a plurality of fastening bores 244, with some of the fastening bores 244 beingarranged on the locking face 242 and some of the fastening bores 244 being arranged between the locking face 242 and the longitudinally-rear end 240. Each of the fastening bores 244 extends through the right-rear side frame member 130 (e.g., through the first side 234 and the second side 236). In some embodiments, the fastening bores 244 arranged outside of the locking face 242 may enable one of the auxiliary components to be coupled to the right-rear side frame member 130 (e.g., the powertrain support tray 156).

[0094] In the illustrated embodiment, the locking face 242 includes two of the tapered bores 170. Each of the tapered bores 170 in the locking face 242 is recessed into the locking face 242 and is axially aligned with a corresponding one of the fastening bores 244 (e.g., the tapered bore 170 is arranged coaxially with a bore axis defined by the corresponding fastening bore 244). In the illustrated embodiment, the tapered bores 170 of the locking face 242 are arranged in opposite corners of the locking face 242. In some embodiments, the locking face 242 includes more or less than two of the tapered bores 170.

[0095] Turning to FIG. 23, a casting part projected area 246 of the right-rear side frame member 130 is shown in cross-hatching. In some embodiments, the casting part projected area 246 of the right-rear side frame member 130 is less than or equal to about 100 in2, or less than or equal to about 90 in2.

[0096] With reference to FIGS. 24 and 25, the right-middle side frame member 134 is shown. The design and elements of the right-middle side frame member 134 are symmetric to the leftmiddle side frame member 136 about the longitudinal plane 108. Therefore, the description herein relating to the right-middle side frame member 134 symmetrically applies to the left-middle side frame member 136, with like elements being identified using similar reference numerals. The right-middle side frame member 134 defines a first or inner-facing side 248, a second or outerfacing side 250, a longitudinally-front end 252, a longitudinally-rear end 254, a top end 255, and a bottom end 257.

[0097] In general, the right-middle side frame member 134 is configured to facilitate an initial coupling and subsequent fastening between two or more components of the chassis 100 at both longitudinal ends of the right-middle side frame member 134. In some embodiments, the rightmiddle side frame member 134 is configured to couple to the right-rear side frame member 130and the rear cross frame member 114 at the longitudinally-rear end 254, and to the right-front side frame member 138 and the middle cross frame member 116 at the longitudinally-front end 252.

[0098] In the illustrated embodiments, the right-middle side frame member 134 includes a first locking face 256, a second locking face 258, a third locking face 260, and a fourth locking face 262. The first locking face 256 and the second locking face 258 are arranged on the first side 248, and the third locking face 260 and the fourth locking face 262 are arranged on the second side 250. The first locking face 256 and the third locking face 260 are arranged adjacent to the longitudinally-rear end 254, and the second locking face 258 and the fourth locking face 262 are arranged adjacent to the longitudinally-front end 252.

[0099] In the illustrated embodiment, the right-middle side frame member 134 includes a plurality of fastening bores 264, with some of the fastening bores 264 extending axially through the first locking face 256 and the third locking face 260, some of the fastening bores 264 extending axially through the second locking face 258 and the fourth locking face 262, and some of the fastening bores 264 being arranged longitudinally between the first, second, third, and fourth locking faces 256, 258, 260, 262. Each of the fastening bores 264 extends through the right-middle side frame member 134 (e.g., through the first side 248 and the second side 250). In some embodiments, the fastening bores 264 arranged remotely from of the first, second, third, and fourth locking faces 256, 258, 260, 262 may enable one of the auxiliary components to be coupled to the right-middle side frame member 134 (e.g., the swing arm pivot bracket 154).

[0100] In the illustrated embodiment, the first locking face 256 includes two of the tapered bores 170. Each of the tapered bores 170 in the first locking face 256 is recessed into the first locking face 256 and is axially aligned with a corresponding one of the fastening bores 264 (e.g., the tapered bore 170 is arranged coaxially with a bore axis defined by the corresponding fastening bore 264). In the illustrated embodiment, the tapered bores 170 of the first locking face 256 are arranged in opposite corners of the first locking face 256. In some embodiments, the first locking face 256 includes more or less than two of the tapered bores 170.

[0101] In the illustrated embodiment, the second locking face 258 includes two of the tapered bores 170. Each of the tapered bores 170 in the second locking face 258 is recessed into the second locking face 258 and is axially aligned with a corresponding one of the fastening bores 264 (e.g., the tapered bore 170 is arranged coaxially with a bore axis defined by the corresponding fasteningbore 264). In the illustrated embodiment, the tapered bores 170 of the second locking face 258 are vertically separated (e.g., from the perspective of FIG. 25) on the second locking face 258. In some embodiments, the second locking face 258 includes more or less than two of the tapered bores 170.

[0102] In the illustrated embodiment, the third locking face 260 includes two of the tapered protrusions 168. Each of the tapered protrusions 168 in the third locking face 260 protrudes from the third locking face 260 and is axially aligned with a corresponding one of the fastening bores 264 (e.g., the tapered protrusion 168 is arranged coaxially with a bore axis defined by the corresponding fastening bore 264). In the illustrated embodiment, the tapered protrusions 168 of the third locking face 260 are arranged in opposite corners of the third locking face 260. Each of the tapered protrusions 168 on the third locking face 260 extends coaxially with a corresponding one of the tapered bores 170 on the first locking face 256 (e.g., extend along a common bore axis). In some embodiments, the third locking face 260 includes more or less than two of the tapered protrusions 168.

[0103] In the illustrated embodiment, the fourth locking face 262 includes two of the tapered protrusions 168. Each of the tapered protrusions 168 in the fourth locking face 262 protrudes from the fourth locking face 262 and is axially aligned with a corresponding one of the fastening bores 264 (e.g., the tapered protrusion 168 is arranged coaxially with a bore axis defined by the corresponding fastening bore 264). In the illustrated embodiment, the tapered protrusions 168 of the fourth locking face 262 are vertically separated (e.g., from the perspective of FIG. 24) on the fourth locking face 262. Each of the tapered protrusions 168 on the fourth locking face 262 extends coaxially with a corresponding one of the tapered bores 170 on the second locking face 258 (e.g., extend along a common bore axis). In some embodiments, the fourth locking face 262 includes more or less than two of the tapered protrusions 168.

[0104] Turning to FIG. 26, a casting part projected area 266 of the right-middle side frame member 134 is shown in cross-hatching. In some embodiments, the casting part projected area 266 of the right-middle side frame member 134 is less than or equal to about 140 in2, or less than or equal to about 130 in2.

[0105] With reference to FIGS. 27 and 28, the right-front side frame member 138 is shown. The design and elements of the right-front side frame member 138 are symmetric to the left-frontside frame member 140 about the longitudinal plane 108. Therefore, the description herein relating to the right-front side frame member 138 symmetrically applies to the left-front side frame member 140, with like elements being identified using similar reference numerals. The right-front side frame member 138 defines a first or inner-facing side 268, a second or outer-facing side 270, a longitudinally-front end 272, a longitudinally-rear end 274, a top end 275, and a bottom end 277. In the illustrated embodiment, the right-front side frame member 138 includes a first locking face 276 arranged on the first side 268 in a location adj acent to the longitudinally-rear end 274, a second locking face 278 arranged on the first side 268 in a location adjacent to the longitudinally-rear end 274, and a third locking face 279 arranged on the first side 268 in a location adjacent to the longitudinally-front end 272. The first locking face 276 is arranged closer to the longitudinally- rear end 274 than the second locking face 278.

[0106] In general, the right-front side frame member 138 includes coupling and fastening features that enable the right-front side frame member 138 to be initially coupled to both the rightmiddle side frame member 134 and the front-right-corner cross frame member 118 and then fastened to both the right-middle side frame member 134 and the front-right-comer cross frame member 118. The right-front side frame member 138 includes a plurality of fastening bores 280, with some of the fastening bores 280 being arranged on the first locking face 276, some of the fastening bores 280 being arranged on the second locking face 278, some of the fastening bores 280 being arranged on the third locking face 279, and some of the fastening bores 280 being arranged longitudinally between the second locking face 278 and the third locking face 279. Each of the fastening bores 280 extends through the right-front side frame member 138 (e.g., through the first side 268 and the second side 270). In some embodiments, the fastening bores 280 arranged between of the second locking face 278 and the third locking face 279 may enable one of the auxiliary components to be coupled to the right-front side frame member 138 (e.g., the footwell support bar 146). For example, the first side 268 of the right-front side frame member 138 includes a recess 281 having a pair of the fastening bores 280 arranged therein. As described herein, in some embodiments, an end of the footwell support bar 146 is configured to be received within the recess 281 and fastened to the right-front side frame member 138.

[0107] In the illustrated embodiment, the first locking face 276 includes two of the tapered bores 170. Each of the tapered bores 170 in the first locking face 276 is recessed into the first locking face 276 and is axially aligned with a corresponding one of the fastening bores 280 (e.g.,the tapered bore 170 is arranged coaxially with a bore axis defined by the corresponding fastening bore 280). In the illustrated embodiment, the tapered bores 170 of the first locking face 276 are vertically separated (e.g., from the perspective of FIG. 28) on the first locking face 276. In some embodiments, the first locking face 276 includes more or less than two of the tapered bores 170.

[0108] In the illustrated embodiment, the third locking face 279 includes two of the tapered bores 170. Each of the tapered bores 170 in the third locking face 279 is recessed into the third locking face 279 and is axially aligned with a corresponding one of the fastening bores 280 (e.g., the tapered bore 170 is arranged coaxially with a bore axis defined by the corresponding fastening bore 280). In the illustrated embodiment, the tapered bores 170 of the third locking face 279 are vertically separated (e.g., from the perspective of FIG. 28) on the third locking face 279. In some embodiments, the third locking face 279 includes more or less than two of the tapered bores 170.

[0109] Turning to FIG. 29, a casting part projected area 282 of the right-front side frame member 138 is shown in cross-hatching. In some embodiments, the casting part projected area 282 of the right-front side frame member 138 is less than or equal to about 140 in2, or less than or equal to about 130 in2.Lattice Structures

[0110] In general, the frame members (e.g., the frame members 114, 116, 118, 120, 122, 130, 132, 134, 136, 138, 140) of the chassis 100 may include a lattice structure integrally formed therein. The use of the term “lattice structure” herein relates to an array of interconnected segments, lines, plates, ribs, or bars that are arranged in a repeating or non-repeating pattern. In some embodiments, one or more of the frame members include a first lattice structure that defines a first pattern and a second lattice structure that defines a second pattern. In some embodiments, the first lattice structure and the second lattice structure may be asymmetrical in pattern and / or location along the respective side of the frame member. The differing structure and pattern in the first lattice structure and the second lattice structure provides particular areas along the frame member (e.g., areas with a lattice structure) with a higher bending moment of inertia, a higher bending stiffness, and removes weight / mass from the frame member, and improves overall performance of the chassis 100. While the asymmetry between the first lattice structure and the second lattice structure allow the mechanical properties of a particular frame member to vary, the inclusion on a lattice structure in general improves the mechanical properties of the frame members(e g., higher bending moment of inertia, higher bending stiffness, less weight / mass), whether or not the lattice structure defines asymmetry with respect to another lattice structure. Further, the various lattice structures are formed on the frame members during the die casting process and are not viable using the manufacturing methods used in conventional chassis.[0U1] In the illustrated embodiment of FIGS. 21 and 22, the right-rear side frame member 130 includes a first lattice structure 284 on the first side 234 and a second lattice structure 286 on the second side 236. The first lattice structure 284 is formed by a first plurality of interconnected segments 288 that define a first pattern, and the second lattice structure 286 is formed by a second plurality of interconnected segments 290 that define a second pattern. Both the first lattice structure 284 and the second lattice structure 286 extend between the longitudinally-front end 238 and the longitudinally-rear end 240, and between the top end 241 and the bottom end 243. In the illustrated embodiment, the first pattern is generally symmetric to the second pattern. The inclusion of the first lattice structure 284 and the second lattice structure 286 on the right-rear side frame member 130 reduces the weight / mas defined by the right-rear side frame member 130 (e.g., compared to solid material), while maintaining or improving the bending moment of inertia and the bending stiffness (e.g., compared to solid material).

[0112] In the illustrated embodiment of FIGS. 24 and 25, the right-middle side frame member 134 includes a first lattice structure 292 on the first side 248 and a second lattice structure 294 on the second side 250. The first lattice structure 292 is formed by a first plurality of interconnected segments 296 that define a first pattern, and the second lattice structure 294 is formed by a second plurality of interconnected segments 298 that define a second pattern. In the illustrated embodiment, the first lattice structure 292 is asymmetrical to the second lattice structure 294. For example, the first pattern defined by the first plurality of interconnected segments 296 is different than the second pattern defined by the second plurality of interconnected segments 298. Additionally, the first lattice structure 292 is arranged at a different location along the first side 248 than the second lattice structure 294 is along the second side 250. For example, the first lattice structure 292 extends from the top end 255 downwardly (e.g., from the perspective of FIG. 25) to a location between the top end 255 and the bottom end 257, and the second lattice structure 294 extends from the bottom end 257 upwardly (e.g., from the perspective of FIG. 24) to a location between the bottom end 257 and the top end 255. The asymmetrical relationship between the first lattice structure 292 and the second lattice structure 294 defines varying mechanical properties(e g., bending moment of inertia, bending stiffness, weight / mass) along the right-middle side frame member 134, which, for example, allows the mechanical properties to be bolstered in areas of interest or high loading / stress.

[0113] In the illustrated embodiment of FIGS. 27 and 28, the right-front side frame member 138 includes a first lattice structure 300 on the first side 268 and a second lattice structure 302 on the second side 270. The first lattice structure 300 is formed by a first plurality of interconnected segments 304 that define a first pattern, and the second lattice structure 302 is formed by a second plurality of interconnected segments 306 that define a second pattern. In the illustrated embodiment, the first lattice structure 300 is asymmetrical to the second lattice structure 302. For example, the first lattice structure 300 is arranged at a different location along the first side 268 than the second lattice structure 302 is along the second side 270. Specifically, the first lattice structure 300 extends from the top end 275 downwardly (e.g., from the perspective of FIG. 28) to the bottom end 277, and the second lattice structure 302 extends from the bottom end 277 upwardly (e g., from the perspective of FIG. 27) to a location between the bottom end 277 and the top end 275. The asymmetrical relationship between the first lattice structure 300 and the second lattice structure 302 defines varying mechanical properties (e.g., bending moment of inertia, bending stiffness, weight / mass) along the right-front side frame member 138, which, for example, allows the mechanical properties to be bolstered in areas of interest or high loading / stress.Self-Locking Tapers

[0114] As described herein, each of the plurality of cross frame members 102 (i.e., the rear cross frame member 114, the middle cross frame member 116, the front-right-corner cross frame member 118, the front-left-comer cross frame member 120, and the front cross frame member 122) and the plurality of side frame members 104 (i.e., the right-rear side frame member 130, the left-rear side frame member 132, the right-middle side frame member 134, the left-middle side frame member 136, the right-front side frame member 138, and the left-front side frame member 140) include some form of a tapered feature (e.g., the tapered bore(s) 168 and / or the tapered protrusion(s) 170). FIGS. 30-37 illustrate the tapered protrusions 168 and the tapered bores 170 on the right side 142 of the middle cross frame member 116, the right-middle side frame member 134, and the right-front side frame member 138. It should be appreciated that the following description of the tapered protrusion 168, the tapered bore 170, the initial coupling formed by thetapered protrusion 168 and the tapered bore 170, and the fastening through the tapered protrusion 168 and the tapered bore 170 applies globally to all of the tapered protrusions 168 and the tapered bores 170 on the corresponding frame members of the chassis 100.

[0115] With reference to FIGS. 30 and 31, the middle cross frame member 116, the rightmiddle side frame member 134, and the right-front side frame member 138 are shown in a disassembled state. In general, the tapered protrusions 168 on the locking face 196 of the middle cross frame member 116 are configured to be inserted into the tapered bores 170 on the second locking face 258 of the right-middle side frame member 134. After a holding force is applied to the right-middle side frame member 134, an interference fit is formed between the tapered protrusions 168 on the locking face 196 of the middle cross frame member 1 16 and the tapered bores 170 on the second locking face 258 of the right-middle side frame member 134. The interference fit provides an initial coupling between the middle cross frame member 116 and the right-middle side frame member 134 that holds the two components together without the use of a fastener. With the middle cross frame member 116 and the right-middle side frame member 134 initially coupled, the tapered protrusions 168 on the fourth locking face 262 of the right-middle side frame member 134 are configured to be inserted into the tapered bores 170 on the first locking face 276 of the right-front side frame member 138. After a holding force is applied to the rightfront side frame member 138, an interference fit is formed between the tapered protrusions 168 on the fourth locking face 262 of the right-middle side frame member 134 and the tapered bores 170 on the first locking face 276 of the right-front side frame member 138. As such, the tapered protrusions 168 and the tapered bores 170 may facilitate forming an initial coupling between two or more of the frame members (e.g., the middle cross frame member 116, the right-middle side frame member 134, and the right-front side frame member 138) without the use of a fastener.

[0116] The initial couplings formed between the middle cross frame member 116, the rightmiddle side frame member 134, and the right-front side frame member 138 also axially aligns various groups of the fastening bores 194 of the middle cross frame member 116, the fastening bores 264 of the right-middle side frame member 134, and the fastening bores 280 of the rightfront side frame member 138. That is, the interference fit formed between the tapered protrusions 168 and the tapered bores 170 also constrains the orientation of the frame members during assembly to align the various fastening bores arranged thereon. In some embodiments, for example, each of the cross frame members 102 (i.e., the rear cross frame member 114, the middlecross frame member 116, the front-right-comer cross frame member 1 18, the front-1 eft-comer cross frame member 120, and the front cross frame member 122) and the plurality of side frame members 104 (i.e., the right-rear side frame member 130, the left-rear side frame member 132, the right-middle side frame member 134, the left-middle side frame member 136, the right-front side frame member 138, and the left-front side frame member 140) includes at least two of the tapered protrusions 168 or the tapered bores 170 to constrain all 6 degrees of freedom during assembly.

[0117] With the initial coupling and alignment formed between the middle cross frame member 116, the right-middle side frame member 134, and the right-front side frame member 138, the weldless assembly of fasteners 112 is configured to fasten these components together with a locking force. In some embodiments, the weldless assembly of fasteners 112 comprises a plurality of threaded fasteners 308 in the form of self-tapping screws. In some embodiments, each of the threaded fasteners 308 is fabricated from a different material than the plurality of cross frame member 102 and the plurality of side frame members 104. In some embodiments, each of the threaded fasteners 308 is fabricated from a steel material. One of the threaded fasteners 308 is inserted through each axially-aligned group of the fastening bores 194, 264, 280 and tightened with a predetermined torque, which generates a locking force between the middle cross frame member 116, the right-middle side frame member 134, and the right-front side frame member 138. In general, the interface between each of the tapered protrusions 168 and the tapered bores 170 is configured to yield when the locking force is applied by the threaded fasteners 308 that are inserted through the respective frame members. The yielding of the interface between the tapered protrusions 168 and the tapered bores 170 is configured to transfer a load-carrying interface to an interface between the respective a locking faces on the frame members. The plastic strain levels at the yielding interface between the tapered protrusions 168 and the tapered bores 170 are maintained below the plastic strain rupture point for the material used to fabricate the frame members (e.g., aluminum, magnesium, etc.) to prevent cracking during fastening.

[0118] In the illustrated embodiment, when the middle cross frame member 116, the rightmiddle side frame member 134, and the right-front side frame member 138 are fastened with the locking force applied by the threaded fasteners 308, the second locking face 258 of the rightmiddle side frame member 134 and the second locking face 278 of the right-front side frame member 138 both engage the locking face 196 of the middle cross frame member 116. Additionally, the fourth locking face 262 of the right-middle side frame member 134 engages thefirst locking face 276 of the right-front side frame member 138. These engagements between the locking faces provide a load-carrying interface for the coupling between the middle cross frame member 116, the right-middle side frame member 134, and the right-front side frame member 138, which is enabled by the yielding at the interface between the tapered protrusions 168 and the tapered bores 170. Transferring the load-carrying interface to the engagement between the respective locking faces 196, 258, 262, 276, 278 provides an increased surface area over which the loads applied to the chassis 100 are carried / supported.

[0119] Turning to FIGS. 32 and 33, each of the tapered protrusions 168 defines a hollow frustoconical shape (e.g., a frustoconical protrusion with one of the fastening bores extending axially through a center of the protrusion). Each of the tapered protrusions 168 includes an outer tapered surface 310 that is angled relative to a fastening axis 312 along which the tapered protrusion 168 extends. Specifically, the outer tapered surface 310 defines a per-side angle 314 between radially-opposing sides (e.g., sides that are 180 degrees apart) of the outer tapered surface 310 and the fastening axis 312, and an included angle 316 between the radially-opposing sides of the outer tapered surface 310. In some embodiments, the per-side angle 314 of the outer tapered surface 310 is less than or equal to about 10 degrees, or less than or equal to about 9 degrees, or less than or equal to about 8 degrees, or less than or equal to about 7 degrees, or less than or equal to about 6 degrees. In some embodiments, the included angle 316 of the outer tapered surface 310 is less than or equal to about 20 degrees, or less than or equal to about 18 degrees, or less than or equal to about 16 degrees, or less than or equal to about 14 degrees, or less than or equal to about 12 degrees, or less than or equal to about 10 degrees. In general, the geometric design of the outer tapered surface 310 provides the self-locking capabilities of the tapered protrusions 168. For example, angles greater than 10 degrees per side or greater than 20 degrees included may not provide self-locking capabilities.

[0120] Turning to FIGS. 34 and 35, each of the tapered bores 170 defines a hollow frustoconical shape in cross-section. Each of the tapered bores 170 includes an inner tapered surface 318 that is angled relative to the fastening axis 312 along which the tapered bore 170 extends. Specifically, the inner tapered surface 318 defines a per-side angle 320 between radially- opposing sides (e.g., sides that are 180 degrees apart) of the inner tapered surface 318 and the fastening axis 312, and an included angle 322 between the radially-opposing sides of the inner tapered surface 318. In some embodiments, the angle defined by the inner tapered surface 318,either on a per-side or included basis, is different than the angle defined by the outer tapered surface 310 of the tapered protrusion 168. In some embodiments, the angle defined by the inner tapered surface 318, either on a per-side or included basis, is less than the angled defined by the inner tapered surface 318. In some embodiments, the per-side angle 320 of the inner tapered surface 318 is about 3 degrees less than the per-side angle 314 of the outer tapered surface 310, or about 2 degrees less than the per-side angle 314 of the outer tapered surface 310, or about 1 degree less than the per-side angle 314 of the outer tapered surface 310. In some embodiments, the included angle 322 of the inner tapered surface 318 is about 6 degrees less than the included angle 316 of the outer tapered surface 310, or about 5 degrees less than the included angle 316 of the outer tapered surface 310, or about 4 degrees less than the included angle 316 of the outer tapered surface 310, or about 3 degrees less than the included angle 316 of the outer tapered surface 310, or about 2 degrees less than the included angle 316 of the outer tapered surface 310, or about 1 degree less than the included angle 316 of the outer tapered surface 310.

[0121] In general, the differing angles between the outer tapered surface 310 and the inner tapered surface 318 ensure that the initial engagement between the tapered protrusion 168 and the tapered bore 170 occurs at a location closer to a base or proximal end of the tapered protrusion 168 (e.g., an end closer to the locking surface from which the tapered protrusion extends). The tapered protrusions 168 define a larger material thickness (e.g., radially) near the base or proximal end thereof, so the stresses associated with the self-locking or initial coupling provided at the interface between the tapered protrusion 168 and the tapered bore 170 are supported by areas of greater material thickness. In some embodiments, however, the angle defined by the inner tapered surface 318 may be about equal to the angle defined by the inner tapered surface 318.

[0122] FIG. 36 illustrates an initial coupling formed between the tapered protrusion 168 of the middle cross frame member 116 and the tapered bore 170 of the right-middle side frame member 134. In the illustrated embodiment, the holding force may be applied in a direction H (e.g., to the right from the perspective of FIG. 36, or in a direction parallel to the fastening axis 312). In some embodiments, the holding force may be applied by a user during assembly, for example, using a mallet, hammer, or equivalent hand tool. The holding force required to achieve the initial coupling between the tapered protrusion 168 and the tapered bore 170 is generally small when compared to the locking force used to fasten the frame members. That is, the holding force used to form theinitial coupling between the tapered protrusion 168 and the tapered bore 170 is less than the locking force applied by the threaded fasteners 308.

[0123] With the middle cross frame member 116 and the right-middle side frame member 134 initially coupled as shown in FIG. 36, the right-middle side frame member 134 is held in place relative to the middle cross frame member 116, which allows a user to step away from the assembly and access another component. For example, the right-front side frame member 138 may be initially coupled to the right-middle side frame member 134 by inserting the tapered bore 170 on the right-front side frame member 138 onto the tapered protrusion 168 of the right-middle side frame member 134. FIG. 37 illustrates an initial coupling formed between the tapered protrusion 168 of the middle cross frame member 116 and the tapered bore 170 of the right-middle side frame member 134, and between the tapered protrusion 168 of the right-middle side frame member 134 and the tapered bore 170 of the right-front side frame member 138. Again, the holding force may be applied in the holding direction H to the right-front side frame member 138 to form the initial coupling. With the middle cross frame member 116, the right-middle side frame member 134, and the right-front side frame member 138 initially coupled, a user may insert one of the threaded fasteners 308 through the axially-aligned fastening bores 194, 264, 280 and apply the predetermined torque to the threaded fastener 308 to apply the locking force. As described herein, the interference fit between the tapered protrusions 168 and the tapered bores 170 is configured to yield during application of the locking force to ensure full face-to-face engagement between the locking faces and transfer a load-carrying interface from the interface between the tapered protrusions 168 and the tapered bores 170 to the interface between the locking faces.

[0124] With reference to FIG. 38, in some embodiments, the tapered protrusions 168 may define a raised rib profile along the outer tapered surface 310. In the illustrated embodiments, the outer tapered surface 310 includes a plurality of raised ribs 324 and a plurality of recesses 326. Each of the raised ribs 324 and the recesses 326 extends axially along the outer tapered surface 310, with the recesses 326 being recessed radially inwardly into the outer tapered surface 310. Each of the raised ribs 324 is arranged circumferentially between a circumferentially-adjacent pair of the recesses 326. In some embodiments, the raised ribs 324 comprise less than 50% of the surface area of the outer tapered surface 310. In this way, for example, less than 50% of the interfacing circumference of the tapered protrusion 168 engages and forms the interference fit between the tapered protrusions 168 and the tapered bores 170. By reducing the amount ofmaterial at the interface between the tapered protrusions 168 and the tapered bores 170, the level of plastic strain needed in order for the yielding to occur at the interface, or bed into a line-on-line fitment by allowing the material from the raised ribs 324 that contact the inner tapered surface 318 to flow into the recesses 326 via a short travel path, is substantially reduced. All interfaces between the raised ribs 324 and the recesses 326 may define a smooth transitions or rounded edge to minimize stress risers.Chassis Manufacturing and Assembly

[0125] FIG. 39 illustrates the steps in a method 400 of manufacturing a chassis (e g., the chassis 100) according an exemplary embodiment of the present disclosure. The method 400 begins at step 402 where frame members of a chassis are formed by a casting process (e.g., a die casting process). For example, the plurality of cross frame members 102 (i.e., the rear cross frame member 114, the middle cross frame member 116, the front-right-comer cross frame member 118, the front-left-comer cross frame member 120, and the front cross frame member 122) and the plurality of side frame members 104 (i.e., the right-rear side frame member 130, the left-rear side frame member 132, the right-middle side frame member 134, the left-middle side frame member 136, the right-front side frame member 138, and the left-front side frame member 140) of the chassis 100 are each formed by a die casting process and are fabricated from a nonferrous metal (e g., aluminum, magnesium, etc ). The frame members 114, 116, 118, 120, 122, 130, 132, 134, 136, 138, 140 are all formed in a die cast mold and a trim die is used to removed excess material from the frame members 114, 116, 118, 120, 122, 130, 132, 134, 136, 138, 140 after initially being formed in the die cast mold. Following the die casting process, including the trim die, the frame members 114, 116, 118, 120, 122, 130, 132, 134, 136, 138, 140 are all in an as-cast state and no additional machining, fabrication, or post-processing is required prior to assembling the frame members 114, 116, 118, 120, 122, 130, 132, 134, 136, 138, 140 into the chassis 100.

[0126] The method 400 then proceeds to step 404 where the frame members 114, 116, 118, 120, 122, 130, 132, 134, 136, 138, 140 in the as-cast state are assembled into the chassis 100 using the tapered protrusions 168 and the tapered bores 170 to form initial couplings, without a fastener, and then subsequently fastening the frame members 114, 116, 118, 120, 122, 130, 132, 134, 136, 138, 140 using the weldless assembly of fasteners 112. Specifically, the threaded fasteners 308are used to apply the locking force between the frame members 114, 1 16, 118, 120, 122, 130, 132, 134, 136, 138, 140 and form the chassis 100.

[0127] FIGS. 40-47 illustrate the steps for assembling the as-cast frame members (e.g., at step 404) to manufacture the chassis 100 in the method 400 according to an exemplary embodiment of the present disclosure. In the illustrated embodiment, at step 406, the plurality of cross frame members 102 (e g., the rear cross frame member 114, the middle cross frame member 116, the front-right-corner cross frame member 118, the front-1 eft-comer cross frame member 120) in the as-cast state are arranged on an assembly jig 500 (see, e.g., FIG. 41). In some embodiments, the footwell support bar 146 is also arranged on the assembly jig 500. In the illustrated embodiments, the assembly jig 500 includes at least two clamps 502 for each of the cross frame members 102 arranged thereon. In some embodiments, the cross frame members 102 may be self-locating, for example, by engaging at least two different surfaces on the cross frame members 102 that are arranged in different directional planes to constrain the locations of the cross frame members 102 within the respective clamps 502. Once the cross frame members 102 are located within the respective clamps 502, the clamps 502 may be clamped down to hold the cross frame members 102 in positon for the remainder of the assembly.

[0128] Once the cross frame members 102 are located and clamped on the assembly jig 500, the right-middle side frame member 134 and the left-middle side frame member 136 are initially coupled to the rear cross frame member 114 and the middle cross frame member 116 (see, e.g., FIG. 42) using the tapered protrusions 168 and the tapered bores 170, at step 408. Specifically, the right-middle side frame member 134 is inserted onto the rear cross frame member 114 and the middle cross frame member 116 so that the tapered protrusions 168 on the locking face 166 of the rear cross frame member 114 are received within the tapered bores 170 on the first locking face 256 of the right-middle side frame member 134 and the tapered protrusions 168 on the locking face 196 of the middle cross frame member 116 are received within the tapered bores 170 on the second locking face 258 of the right-middle side frame member 134. The holding force is then applied to the right-middle side frame member 134 to generate the interference fit between the tapered protrusions 168 and the tapered bores 170 that forms the initial coupling between the rightmiddle side frame member 134 and both of the rear cross frame member 114 and the middle cross frame member 116, which holds the right-middle side frame member 134 in place relative to the rear cross frame member 114 and the middle cross frame member 116. The left-middle side framemember 136 is initially coupled to the laterally-opposing sides of the rear cross frame member 1 14 and the middle cross frame member 116 in the same way.

[0129] At step 410, the right-front side frame member 138 is then initially coupled to the rightmiddle side frame member 134 and the front-right-corner cross frame member 118, and the leftfront side frame member 140 is initially coupled to the left-middle side frame member 136 and the front-left-comer cross frame member 120 using the tapered protrusions 168 and the tapered bores 170. Specifically, the right-front side frame member 138 is inserted onto the right-middle side frame member 134 and the front-right-corner cross frame member 118 so that the tapered protrusions 168 on the fourth locking face 262 of the right-middle side frame member 134 are received within the tapered bores 170 on the first locking face 276 of the right-front side frame member 138, and the tapered protrusions 168 on the second locking face 214 of the front-right- corner cross frame member 118 are received within the tapered bores 170 on the third locking face 279 of the right-front side frame member 138. The holding force is then applied to the right-front side frame member 138 to generate the interference fit between the tapered protrusions 168 and the tapered bores 170 that forms the initial coupling between the right-front side frame member 138 and both of the right-middle side frame member 134 and the front-right-corner cross frame member 118, which holds the right-front side frame member 138 in place relative to the rightmiddle side frame member 134 and the front-right-comer cross frame member 118. The left-front side frame member 140 is initially coupled to the left-middle side frame member 136 and the frontleft-corner cross frame member 120 in the same way.

[0130] As described herein, the tapered protrusions 168 and the tapered bores 170 provide both holding and aligning capabilities so that the frame members are both held in place upon formation of the initial couplings and the fastening bores on the frame members are axially aligned to enable fastening of the frame members. In the some embodiments, as the right-front side frame member 138 and the left-front side frame member 140 are inserted onto the assembly, the arrangement of the tapered protrusions 168 and the tapered bores 170 may align the distal ends of the footwell support bar 146 within the recesses 281 on the right-front side frame member 138 and the leftfront side frame member 140.

[0131] With particular groups of the fastening bores 194, 220, 264, 280 aligned via the initial coupling formed by the tapered protrusions 168 and the tapered bores 170, the right-front sideframe member 138 is fastened to the middle cross frame member 116 and the front-right-corner cross frame member 118 via the threaded fasteners 308, and the left-front side frame member 140 is fastened to the middle cross frame member 116 and the front-left-corner cross frame member 120 via the threaded fasteners 308, at step 412 (see, e.g., FIG. 43). As described herein, the threaded fasteners 308 apply a locking force that is configured to cause yielding at the interfaces between the tapered protrusions 168 and the tapered bores 170 to generate face-to-face engagement at the locking faces and transfer the load-carrying interface to the interface between the locking faces, which increases the load-carrying area at the joints formed between the frame members. In the illustrated embodiment, the locking force generates face-to-face engagement between the locking face 196 of the middle cross frame member 116 and both the second locking face 258 of the right-middle side frame member 134 and the second locking face 278 of the right-front side frame member 138, and between the fourth locking face 262 of the right-middle side frame member 134 and the first locking face 276 of the right-front side frame member 138. Similar engagements occur between the corresponding locking faces on the left side 144 between the middle cross frame member 116, the left-middle side frame member 136, and the left-front side frame member 140. In some embodiments, the right-front side frame member 138 and the leftfront side frame member 140 are fastened to the footwell support bar 146 via the threaded fasteners 308 being inserted through the fastening bores 280 within the recesses 281.

[0132] At step 414, the right-rear side frame member 130 and the left-rear side frame member 132 are initially coupled to the right-middle side frame member 134 and the left-middle side frame member 136, respectively, using the tapered protrusions 168 and the tapered bores 170. Specifically, the right-rear side frame member 130 is inserted onto the right-middle side frame member 134 so that the tapered protrusions 168 on the third locking face 260 of the right-middle side frame member are received within the tapered bores 170 on the locking face 242 of the rightrear side frame member 130. The holding force is then applied to the right-rear side frame member 130 to generate the interference fit between the tapered protrusions 168 and the tapered bores 170 that forms the initial coupling between the right -rear side frame member 130 and the right-middle side frame member 134, which holds the right-rear side frame member 130 in place relative to the right-middle side frame member 134. The left-rear side frame member 132 is initially coupled to the left-middle side frame member 136 in the same way.

[0133] At step 416, with particular groups of the fastening bores 164, 244, 264 aligned via the initial coupling formed by the tapered protrusions 168 and the tapered bores 170, the right-rear side frame member 130 is fastened to the right-middle side frame member 134 and the rear cross frame member 114 via the threaded fasteners 308, and the left-rear side frame member 132 is fastened to the left-middle side frame member 136 and the rear cross frame member 114 via the threaded fasteners 308 (see, e.g., FIG. 44). The locking force applied by the threaded fasteners 308 generates face-to-face engagement between the locking face 166 of the rear cross frame member 114 and the first locking face 256 of the right-middle side frame member 134, and between the third locking face 260 of the right-middle side frame member 134 and the locking face 242 of the right-rear side frame member 130. Similar engagements occur between the corresponding locking faces on the left side 144 between the rear cross frame member 114, the left-rear side frame member 132, and the left-middle side frame member 136.

[0134] At step 418, the front cross frame member 122 is initially coupled to the front-right- corner cross frame member 118 and the front-1 eft-corner cross frame member 120 using the tapered protrusions 168 and the tapered bores 170. Specifically, the front cross frame member 122 is inserted onto the front-right-corner cross frame member 118 and the front-left-comer cross frame member 120 so that the tapered protrusions 168 on the first locking face 212 of the front-right- corner cross frame member 118 are received within the tapered bores 170 on the first locking face 224 of the front cross frame member 122, and the tapered protrusions 168 on the first locking face 212 of the front-left-corner cross frame member 120 are received within the tapered bores 170 on the second locking face 226 of the front cross frame member 122. The holding force is then applied to the front cross frame member 122 to generate the interference fit between the tapered protrusions 168 and the tapered bores 170 that forms the initial coupling between the front cross frame member 122 and both the front-right-corner cross frame member 118 and the front-left-corner cross frame member 120, which holds the front cross frame member 122 in place relative to the front-right- corner cross frame member 118 and the front-left-corner cross frame member 120.

[0135] At step 420, with particular groups of the fastening bores 218, 228, 230 aligned via the initial coupling formed by the tapered protrusions 168 and the tapered bores 170, the front cross frame member 122 is fastened to the front-right-comer cross frame member 118 and the frontleft-comer cross frame member 120 via the threaded fasteners 308 (see, e g., FIG. 44). The locking force applied by the threaded fasteners 308 generates face-to-face engagement between the firstlocking face 212 of the front-right-corner cross frame member 118 and the first locking face 224 of the front cross frame member 122, and between the first locking face 212 of the front-left-corner cross frame member 120 and the second locking face 226 of the front cross frame member 122.

[0136] With all of the frame members 114, 116, 118, 120, 122, 130, 132, 134, 136, 138, 140 fastened, the chassis 100 is in an assembled state and, in some embodiments, at step 422, one or more auxiliary components are fastened to the chassis 100. For example, one of the footwell support brackets 148 may be fastened, via the threaded fasteners 308, to each of the front-right- corner cross frame member 118 and the front-left-corner cross frame member 120 (see, e.g., FIG. 44). In some embodiments, the powertrain support tray 156 may be fastened, via the threaded fasteners 308, to each of the rear cross frame member 114, the right-rear side frame member 130, and the left-rear side frame member 132 (see, e.g., FIG. 45). In some embodiments, at step 422, the shock mount brackets 150 and / or the control arm brackets 152 are fastened to the chassis 100 in their respective locations.

[0137] At step 424, the assembled chassis 100 is removed from the assembly jig 500 and carried through a painting process. For example, the assembled chassis 100 may be powder coated at step 424 (see, e.g., FIG. 46). As described herein, the chassis 100 is assembled prior to the painting at step 424 to mitigate the need for managing paint finishes that can negatively impact load-carrying interface performance at the joints between the frame members. The chassis 100 may be powder coated as a complete unit and then placed back on the assembly jig 500 for installation of a powertrain at step 426 (see, e.g., FIG. 47). In some embodiments, the powertrain is supported on the powertrain support tray 156. In some embodiments, the powertrain is in the form of an internal combustion engine, an energy storage system (e.g., one or more battery cells or battery packs), or a hybrid powertrain that includes both an internal combustion engine and an energy storage system.

[0138] In general, forming the chassis 100 from a die casting process using a non-ferrous material (e.g., aluminum, magnesium, etc.) substantially reduces the weight of the chassis 100, when compared to conventional chassis made from steel. The reduced weight defined by the chassis 100 provide particular benefits in electrified applications, where increased runtime requires larger or more battery packs and additional weight supported on the chassis 100. Also, the chassis 100 is assembled using the threaded fasteners 308, which can be installed using hand tools and areconfigured to provide a torque-controlled fastening interface. That is, the tightening torque applied to the threaded fasteners 308 may be controlled during assembly and the corresponding locking force is maintained consistent as multiple units of the chassis 100 are manufactured in large-scale quantities. In addition, the use of the threaded fasteners 308 provide the ability to loosen and subsequently retighten one or more of the threaded fasteners 308 during assembly to precisely produce stretch on the threaded fastener 308 and ensure long-term torque retention over time. In general, the second tightening does not need substantial torque to create threads or bed in the tapper allowing for quality tension and stretch control. Further, the design and properties of the chassis 100 easily accommodate different sized applications (e.g., wider) by increasing the lateral length defined by the cross frame members 102.

[0139] As utilized herein with respect to numerical ranges, the terms “approximately,” “about,” “substantially,” and similar terms generally mean + / - 10% of the disclosed values. When the terms “approximately,” “about,” “substantially,” and similar terms are applied to a structural feature (e.g., to describe its shape, size, orientation, direction, etc.), these terms are meant to cover minor variations in structure that may result from, for example, the manufacturing or assembly process and are intended to have a broad meaning in harmony with the common and accepted usage by those of ordinary skill in the art to which the subject matter of this disclosure pertains. Accordingly, these terms should be interpreted as indicating that insubstantial or inconsequential modifications or alterations of the subject matter described and claimed are considered to be within the scope of the disclosure as recited in the appended claims.

[0140] It should be noted that the term “exemplary” and variations thereof, as used herein to describe various embodiments, are intended to indicate that such embodiments are possible examples, representations, or illustrations of possible embodiments (and such terms are not intended to connote that such embodiments are necessarily extraordinary or superlative examples).

[0141] The term “coupled” and variations thereof, as used herein, means the joining of two members directly or indirectly to one another. Such joining may be stationary (e.g., permanent or fixed) or moveable (e.g., removable or releasable). Such joining may be achieved with the two members coupled directly to each other, with the two members coupled to each other using a separate intervening member and any additional intermediate members coupled with one another, or with the two members coupled to each other using an intervening member that is integrallyformed as a single unitary body with one of the two members. If “coupled” or variations thereof are modified by an additional term (e.g., directly coupled), the generic definition of “coupled” provided above is modified by the plain language meaning of the additional term (e.g., “directly coupled” means the joining of two members without any separate intervening member), resulting in a narrower definition than the generic definition of “coupled” provided above. Such coupling may be mechanical, electrical, or fluidic.

[0142] References herein to the positions of elements (e.g., “top,” “bottom,” “above,” “below”) are merely used to describe the orientation of various elements in the FIGURES. It should be noted that the orientation of various elements may differ according to other exemplary embodiments, and that such variations are intended to be encompassed by the present disclosure.

[0143] The hardware and data processing components used to implement the various processes, operations, illustrative logics, logical blocks, modules and circuits described in connection with the embodiments disclosed herein may be implemented or performed with a general purpose single- or multi-chip processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, or, any conventional processor, controller, microcontroller, or state machine. A processor also may be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. In some embodiments, particular processes and methods may be performed by circuitry that is specific to a given function. The memory (e.g., memory, memory unit, storage device) may include one or more devices (e.g., RAM, ROM, Flash memory, hard disk storage) for storing data and / or computer code for completing or facilitating the various processes, layers and modules described in the present disclosure. The memory may be or include volatile memory or non-volatile memory, and may include database components, object code components, script components, or any other type of information structure for supporting the various activities and information structures described in the present disclosure. According to an exemplary embodiment, the memory is communi cably connected to the processor via a processing circuit and includes computer code forexecuting (e.g., by the processing circuit or the processor) the one or more processes described herein.

[0144] The present disclosure contemplates methods, systems and program products on any machine-readable media for accomplishing various operations. The embodiments of the present disclosure may be implemented using existing computer processors, or by a special purpose computer processor for an appropriate system, incorporated for this or another purpose, or by a hardwired system. Embodiments within the scope of the present disclosure include program products comprising machine-readable media for carrying or having machine-executable instructions or data structures stored thereon. Such machine-readable media can be any available media that can be accessed by a general purpose or special purpose computer or other machine with a processor. By way of example, such machine-readable media can comprise RAM, ROM, EPROM, EEPROM, or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to carry or store desired program code in the form of machine-executable instructions or data structures and which can be accessed by a general purpose or special purpose computer or other machine with a processor. Combinations of the above are also included within the scope of machine-readable media. Machine-executable instructions include, for example, instructions and data which cause a general purpose computer, special purpose computer, or special purpose processing machines to perform a certain function or group of functions.

[0145] Although the figures and description may illustrate a specific order of method steps, the order of such steps may differ from what is depicted and described, unless specified differently above. Also, two or more steps may be performed concurrently or with partial concurrence, unless specified differently above. Such variation may depend, for example, on the software and hardware systems chosen and on designer choice. All such variations are within the scope of the disclosure. Likewise, software implementations of the described methods could be accomplished with standard programming techniques with rule-based logic and other logic to accomplish the various connection steps, processing steps, comparison steps, and decision steps.

[0146] It is important to note that the construction and arrangement of the chassis 100 as shown in the various exemplary embodiments is illustrative only. It should be appreciated that otherelements of the various embodiments may be incorporated or utilized with any of the other embodiments disclosed herein.

Claims

WHAT IS CLAIMED IS:

1. A chassis comprising: a right-side frame member; a left-side frame member; a cross frame member extending laterally between the right-side frame member and the left-side frame member, wherein the right-side frame member and the left-side frame member are coupled to the cross frame member using a weldless assembly of fasteners.

2. The chassis of claim 1, wherein the right-side frame member, the left-side frame member, and the cross frame member are all formed by a casting process.

3. The chassis of claim 2, wherein each of the right-side frame member, the left-side frame member, and the cross frame member define a casting part projected area that is less than or equal to about 150 in2.

4. The chassis of claim 2, wherein the right-side frame member, the left-side frame member, and the cross frame member are all fabricated from a nonferrous metal.

5. The chassis of claim 4, wherein the weldless assembly of fasteners includes a plurality of fasteners that are fabricated from a different material than the nonferrous metal.

6. The chassis of claim 4, wherein the weldless assembly of fasteners includes a plurality of fasteners that are fabricated from a steel material.

7. The chassis of claim 1, wherein the right-side frame member includes a tapered bore, and the cross frame member includes a tapered protrusion.

8. The chassis of claim 7, wherein when the tapered protrusion is inserted into the tapered bore and a holding force is applied to the right-side frame member, an interface between the tapered protrusion and the tapered bore is configured to form an initial coupling between the right-side frame member and the cross frame member.

9. The chassis of claim 8, wherein the interface between the tapered protrusion and the tapered bore is configured to yield when a locking force is applied by a threaded fastener of the weldless assembly of fasteners that is inserted through the right-side frame member and at least partially into the cross frame member.

10. The chassis of claim 9, wherein the yielding of the interface between the tapered protrusion and the tapered bore is configured to transfer a load-carrying interface to an interface between a locking face of the right-side frame member and a locking face of the cross frame member.

11. The chassis of claim 7, wherein the tapered protrusion defines an outer tapered surface that is angled relative to a fastening axis extending through the tapered protrusion.

12. The chassis of claim 11, wherein the tapered bore defines an inner tapered surface that is angled relative to the fastening axis.

13. The chassis of claim 12, wherein an angle defined between the outer tapered surface and the fastening axis is different than an angle defined between the inner tapered surface and the fastening axis.

14. The chassis of claim 11, wherein the outer tapered surface defines a raised rib profile that includes a plurality of raised ribs and a plurality of recesses, with each of the plurality of raised ribs being arranged between a circumferenti ally-adjacent pair of the plurality of recesses.

15. The chassis of claim 1, wherein the right-side frame member includes a first side and a second side, and wherein the first side includes a first lattice structure having a first plurality of interconnected segments.

16. The chassis of claim 15, wherein the second side includes a second lattice structure having a second plurality of interconnected segments.

17. The chassis of claim 16, wherein the first lattice structure and the second lattice structure are asymmetrical.

18. A chassi s compri sing : a first frame member; and a second frame member, wherein the first frame member and the second frame member are fabricated from a nonferrous metal, and wherein the first frame member is fastened to the second frame member by a threaded fastener, the threaded fastener being fabricated from a steel material.

19. The chassis of claim 18, wherein the first frame member and the second frame member are both formed by a casting process.

20. The chassis of claim 19, wherein each of the first frame member and the second frame member define a casting part projected area that is less than or equal to about 150 in2.

21. The chassis of claim 19, wherein the first frame member and the second frame member are both fabricated from aluminum.

22. The chassis of claim 18, wherein the threaded fastener forms a part of a weldless assembly of fasteners that forms a coupling between the first frame member and the second frame member.

23. The chassis of claim 18, wherein the first frame member includes a tapered bore, and the second frame member includes a tapered protrusion.

24. The chassis of claim 23, wherein when the tapered protrusion is inserted into the tapered bore and a holding force is applied to the first frame member, an interface between the tapered protrusion and the tapered bore is configured to form an initial coupling between the first frame member and the second frame member.

25. The chassis of claim 24, wherein the interface between the tapered protrusion and the tapered bore is configured to yield when a locking force is applied by the threaded fastener that is inserted through the first frame member and at least partially into the second frame member.

26. The chassis of claim 25, wherein the yielding of the interface between the tapered protrusion and the tapered bore is configured to transfer a load-carrying interface to an interface between a locking face of the first frame member and a locking face of the second frame member.

27. The chassis of claim 23, wherein the tapered protrusion defines an outer tapered surface that is angled relative to a fastening axis extending through the tapered protrusion.

28. The chassis of claim 27, wherein the tapered bore defines an inner tapered surface that is angled relative to the fastening axis.

29. The chassis of claim 28, wherein an angle defined between the outer tapered surface and the fastening axis is different than an angle defined between the inner tapered surface and the fastening axis.

30. The chassis of claim 27, wherein the outer tapered surface defines a raised rib profile that includes a plurality of raised ribs and a plurality of recesses, with each of the pluralityof raised ribs being arranged between a circumferentially-adjacent pair of the plurality of recesses.

31. The chassis of claim 18, wherein the first frame member includes a first side and a second side, and wherein the first side includes a first lattice structure having a first plurality of interconnected segments.

32. The chassis of claim 31, wherein the second side includes a second lattice structure having a second plurality of interconnected segments.

33. The chassis of claim 32, wherein the first lattice structure and the second lattice structure are asymmetrical.

34. A chassis comprising: a first frame member including a tapered protrusion; a second frame member including a tapered bore; wherein when the tapered protrusion is inserted into the tapered bore and a holding force is applied to the second frame member, an interface between the tapered protrusion and the tapered bore is configured to form an initial coupling between the first frame member and the second frame member.

35. The chassis of claim 34, wherein the interface between the tapered protrusion and the tapered bore is configured to yield when a locking force is applied by a threaded fastener that is inserted through the second frame member and at least partially into the first frame member.

36. The chassis of claim 35, wherein the yielding of the interface between the tapered protrusion and the tapered bore is configured to transfer a load-carrying interface to an interface between a locking face of the first frame member and a locking face of the second frame member.

37. The chassis of claim 35, wherein the threaded fastener forms a part of a weldless assembly of fasteners that forms a coupling between the first frame member and the second frame member.

38. The chassis of claim 34, wherein the tapered protrusion defines an outer tapered surface that is angled relative to a fastening axis extending through the tapered protrusion.

39. The chassis of claim 38, wherein the tapered bore defines an inner tapered surface that is angled relative to the fastening axis.

40. The chassis of claim 39, wherein an angle defined between the outer tapered surface and the fastening axis is different than an angle defined between the inner tapered surface and the fastening axis.

41. The chassis of claim 34, wherein the first frame member and the second frame member are both formed by a casting process.

42. The chassis of claim 41, wherein each of the first frame member and the second frame member define a casting part projected area that is less than or equal to about 150 in2.

43. The chassis of claim 42, wherein the first frame member and the second frame member are both fabricated from a nonferrous metal.

44. The chassis of claim 34, wherein the second frame member includes a first side and a second side, and wherein the first side includes a first lattice structure having a first plurality of interconnected segments.

45. The chassis of claim 44, wherein the second side includes a second lattice structure having a second plurality of interconnected segments.

46. The chassis of claim 45, wherein the first lattice structure and the second lattice structure are asymmetrical.

47. A chassis comprising: a plurality of side frame members; and a plurality of cross frame members, each extending laterally relative to the plurality of side frame members; wherein each of the plurality of side frame members and the plurality of cross frame members defines a casting part projected area that is less than or equal to 150 in2.

48. The chassis of claim 47, wherein the plurality of side frame members and the plurality of cross frame members are all fabricated from a nonferrous metal.

49. The chassis of claim 48, wherein the plurality of side frame members and the plurality of cross frame members are coupled to one another by a weldless assembly of fasteners that includes a plurality of fasteners that are fabricated from a different material than the nonferrous metal.

50. The chassis of claim 49, wherein the plurality of fasteners are fabricated from a steel material.

51. The chassis of claim 47, wherein the plurality of side frame members includes a right-side frame member and a left-side frame member, and the plurality of cross frame membersincludes a middle cross frame member extending laterally between the right-side frame member and the left-side frame member.

52. The chassis of claim 51 , wherein the right-side frame member includes a tapered bore, and the middle cross frame member includes a tapered protrusion.

53. The chassis of claim 52, wherein when the tapered protrusion is inserted into the tapered bore and a holding force is applied to the right-side frame member, an interface between the tapered protrusion and the tapered bore is configured to form an initial coupling between the right-side frame member and the middle cross frame member.

54. The chassis of claim 53, wherein the interface between the tapered protrusion and the tapered bore is configured to yield when a locking force is applied by a threaded fastener that is inserted through the right-side frame member and at least partially into the middle cross frame member.

55. The chassis of claim 54, wherein the yielding of the interface between the tapered protrusion and the tapered bore is configured to transfer a load-carrying interface to an interface between a locking face of the right-side frame member and a locking face of the middle cross frame member.

56. The chassis of claim 52, wherein the tapered protrusion defines an outer tapered surface that is angled relative to a fastening axis extending through the tapered protrusion.

57. The chassis of claim 56, wherein the tapered bore defines an inner tapered surface that is angled relative to the fastening axis.

58. The chassis of claim 57, wherein an angle defined between the outer tapered surface and the fastening axis is different than an angle defined between the inner tapered surface and the fastening axis.

59. The chassis of claim 56, wherein the outer tapered surface defines a raised rib profile that includes a plurality of raised ribs and a plurality of recesses, with each of the plurality of raised ribs being arranged between a circumferentially-adjacent pair of the plurality of recesses.

60. The chassis of claim 47, wherein one of the plurality of side frame members includes a first side and a second side, and wherein the first side includes a first lattice structure having a first plurality of interconnected segments.

61. The chassis of claim 60, wherein the second side includes a second lattice structure having a second plurality of interconnected segments.

62. The chassis of claim 61, wherein the first lattice structure and the second lattice structure are asymmetrical.

63. A chassis comprising: a frame member including a first side and a second side, wherein the first side includes a first lattice structure having a first plurality of interconnected segments, wherein the second side includes a second lattice structure having a second plurality of interconnected segments, and wherein the first lattice structure and the second lattice structure are asymmetrical.

64. The chassis of claim 63, wherein the frame member is formed by a casting process.

65. The chassis of claim 64, wherein the frame member defines a casting part projected area that is less than or equal to about 150 in2.

66. The chassis of claim 63, wherein the frame member is fabricated from a nonferrous metal.

67. The chassis of claim 66, wherein the frame member is coupled to a second frame member by a weldless assembly of fasteners that forms a coupling between the frame member and the second frame member.

68. The chassis of claim 67, wherein the weldless assembly of fasteners includes a plurality of fasteners that are fabricated from a different material than the nonferrous metal.

69. The chassis of claim 68, wherein the plurality of fasteners are fabricated from steel.

70. The chassis of claim 67, wherein the frame member includes a tapered bore, and the second frame member includes a tapered protrusion.

71. The chassis of claim 70, wherein when the tapered protrusion is inserted into the tapered bore and a holding force is applied to the frame member, an interface between the tapered protrusion and the tapered bore is configured to form an initial coupling between the frame member and the second frame member.

72. The chassis of claim 71, wherein the interface between the tapered protrusion and the tapered bore is configured to yield when a locking force is applied by a threaded fastener of the weldless assembly of fasteners that is inserted through the frame member and at least partially into the second frame member.

73. The chassis of claim 72, wherein the yielding of the interface between the tapered protrusion and the tapered bore is configured to transfer a load-carrying interface to an interface between a locking face of the frame member and a locking face of the second frame member.

74. The chassis of claim 70, wherein the tapered protrusion defines an outer tapered surface that is angled relative to a fastening axis extending through the tapered protrusion.

75. The chassis of claim 74, wherein the tapered bore defines an inner tapered surface that is angled relative to the fastening axis.

76. The chassis of claim 75, wherein an angle defined between the outer tapered surface and the fastening axis is different than an angle defined between the inner tapered surface and the fastening axis.

77. The chassis of claim 74, wherein the outer tapered surface defines a raised rib profile that includes a plurality of raised ribs and a plurality of recesses, with each of the plurality of raised ribs being arranged between a circumferentially-adjacent pair of the plurality of recesses.

78. A method of manufacturing a chassis, the method comprising: casting a first frame member; casting a second frame member, wherein the first frame member and the second frame member are fabricated from a nonferrous metal; and fastening the first frame member to the second frame member with a fastener, wherein the fastener is fabricated from a different material than the nonferrous metal.

79. The method of claim 78, wherein the first frame member and the second frame member are both fabricated from aluminum.

80. The method of claim 78, further comprising: inserting a tapered protrusion of the first frame member into a tapered bore of the second frame member; and applying a holding force to the second frame member to form an initial coupling between the first frame member and the second frame member at an interface between the tapered protrusion and the tapered bore.81 . The method of claim 80, wherein fastening the first frame member to the second frame member with the fastener comprises: applying a locking force to the fastener so that yielding occurs at the interface between the tapered protrusion and the tapered bore.

82. The method of claim 78, wherein casting the first frame member comprises: forming a first lattice structure having a first plurality of interconnected segments in a first side of the first frame member; and forming a second lattice structure having a second plurality of interconnected segments in a second side of the first frame member.

83. The method of claim 82, wherein the first lattice structure is asymmetric to the second lattice structure.

84. A method of manufacturing a chassis, the method comprising: casting a first frame member, the first frame member including a tapered protrusion; casting a second frame member, the second frame member including a tapered bore; inserting the tapered protrusion into the tapered bore and applying a holding force to the second frame member to form an initial coupling between the first frame member and the second frame member at an interface between the tapered protrusion and the tapered bore; and fastening the first frame member to the second frame member by applying a locking force to a threaded fastener so that yielding occurs at the interface between the tapered protrusion and the tapered bore.

85. The method of claim 84, wherein the first frame member and the second frame member are both fabricated from a nonferrous metal.

86. The method of claim 85, wherein the threaded fastener is fabricated from a different material than the nonferrous metal.

87. The method of claim 84, wherein casting the second frame member comprises: forming a first lattice structure having a first plurality of interconnected segments in a first side of the second frame member; and forming a second lattice structure having a second plurality of interconnected segments in a second side of the second frame member.

88. The method of claim 82, wherein the first lattice structure is asymmetric to the second lattice structure.

89. A method of manufacturing a chassis, the method comprising: forming a plurality of side frame members via a die casting process; forming a plurality of cross frame members via the die casting process; and fastening the plurality of side frame members to the plurality of cross frame members using a weldless assembly of fasteners.

90. The method of claim 89, wherein the plurality of side frame members and the plurality of cross frame members are fabricated from a nonferrous metal.

91. The method of claim 90, wherein the weldless assembly of fasteners are fabricated from a different material than the nonferrous metal.

92. The method of claim 89, further comprising: inserting a tapered protrusion of one of the plurality of cross frame members into a tapered bore of one of the plurality of side frame members; and applying a holding force to the one of the plurality of side frame members to form an initial coupling between the one of the plurality of side frame members and the one of the plurality of cross frame members at an interface between the tapered protrusion and the tapered bore.

93. The method of claim 92, further comprising: applying a locking force to a fastener of the weldless assembly of fasteners so that yielding occurs at the interface between the tapered protrusion and the tapered bore.

94. The method of claim 89, wherein casting one of the plurality of side frame members comprises: forming a first lattice structure having a first plurality of interconnected segments in a first side of the one of the plurality of side frame members; and forming a second lattice structure having a second plurality of interconnected segments in a second side of the one of the plurality of side frame members.

95. The method of claim 94, wherein the first lattice structure is asymmetric to the second lattice structure.

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