Patent ID: 12195119

While the present disclosure is subject to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and will herein be described in detail. The present disclosure should be understood to not be limited to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure.

DETAILED DESCRIPTION

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure. It will be apparent, however, to one of ordinary skill in the art that the modular front drivetrain and methods disclosed herein may be practiced without these specific details. In other instances, specific numeric references such as “first joint,” may be made. However, the specific numeric reference should not be interpreted as a literal sequential order but rather interpreted that the “first joint” is different than a “second joint.” Thus, the specific details set forth are merely exemplary. The specific details may be varied from and still be contemplated to be within the spirit and scope of the present disclosure. The term “coupled” is defined as meaning connected either directly to the component or indirectly to the component through another component. Further, as used herein, the terms “about,” “approximately,” or “substantially” for any numerical values or ranges indicate a suitable dimensional tolerance that allows the part or collection of components to function for its intended purpose as described herein.

A double wishbone suspension generally comprises upper and lower suspension arms that operably couple a front wheel of a vehicle. The upper and lower suspension arms each typically include two mounting points to a chassis of the vehicle and one mounting joint at a spindle assembly. The spindle assembly is coupled between the outboard ends of the upper and lower suspension arms and is configured to allow vertical and horizontal radial movement of a wheel coupled with the spindle assembly. Constant velocity (CV) joints allow pivoting of the suspension arms and the spindle assembly, while a drive shaft coupled to the CV joint conveys power from a transaxle to the wheel. Given that off-road vehicles routinely travel over very rough terrain, such as mountainous regions, there is a desire to improve the mechanical strength and performance of off-road drivetrain and suspension systems, while at the same reducing the mechanical complexity of such systems. Embodiments of the disclosure provide to a modular front drivetrain comprising a single assembly that may be installed onto and removed from a vehicle.

FIG.1shows an off-road vehicle100that is particularly suitable for implementation of a modular front drivetrain in accordance with the present disclosure. As disclosed hereinabove, the off-road vehicle100generally is of a Utility Task Vehicle (UTV) variety that seats two occupants, includes a roll-over protection system104, and may have a cab enclosure108. Rear wheels112of the off-road vehicle100may be operably coupled with a chassis116by way of a trailing arm suspension system. Front wheels120may be operably coupled with the chassis116by way of a front suspension system and a spindle assembly. It should be understood, however, that the modular front drivetrain disclosed herein is not to be limited to the off-road vehicle100, but rather the modular front drivetrain may be incorporated into a wide variety of vehicles, other than UTVs, without limitation.

FIG.2illustrates an upper perspective view of a driver-side portion of an exemplary embodiment of a modular front drivetrain124that may be implemented in the off-road vehicle100. The modular front drivetrain124includes a modular chassis128that supports a transaxle132, a front differential136, and a steering gear140that are operably coupled with a spindle assembly144and the front wheel120by way of a front suspension system148. Further, the modular chassis128provides mounting points for the front suspension148, in lieu of conventional mounting points that comprise portions of the chassis116of the vehicle. It is to be understood, therefore, that the modular front drivetrain124comprises a single drivetrain/suspension assembly that may be installed onto and removed from the vehicle100, unlike a conventional drivetrain and suspension that comprise multiple components that must be individually assembled onto the chassis116of the vehicle.

The front suspension system148includes an upper control arm (UCA)152and a lower control arm (LCA)156that couple the front wheel120with the modular chassis128. The UCA152comprises two inboard UCA joints160that couple the UCA152to the modular chassis128and an outboard UCA joint164that couples the UCA152to the spindle assembly144. As best shown inFIG.3, the LCA156includes two inboard LCA joints168that couple the LCA156to the modular chassis128and an outboard LCA joint172that couples the LCA156to the spindle assembly144. As will be recognized, the UCA and LCA152,156generally are of a double wishbone variety of suspension that facilitates vertical motion of the front wheel120during travel over terrain, as well as facilitating horizontal motion of the front wheel120during steering of the vehicle100by way of the steering gear140. The UCA and LCA152,156further facilitate controlling various parameters affecting the orientation of the front wheel120with respect to the off-road vehicle100, such as, by way of non-limiting example, camber angle, caster angle, toe pattern, roll center height, scrub radius, and scrub.

It should be understood that although the front suspension system148is disclosed specifically in connection with the driver-side of the off-road vehicle100, a passenger-side front suspension system is to be coupled with a passenger side of the modular chassis128. It should be further understood that the passenger-side front suspension system is substantially identical to the driver-side front suspension system148, with the exception that the passenger-side front suspension system is configured specifically to operate with the passenger-side of the modular chassis128. As will be appreciated, therefore, the passenger-side front suspension system and the driver-side front suspension system148may be configured as reflections of one another across a longitudinal midline of the off-road vehicle100.

As shown inFIGS.2-3, a strut176that is comprised of a shock absorber and a coil spring is mounted to the LCA156by way of a lower pivot (not shown). A top of the strut176is coupled to an upper pivot (not shown) that may be disposed on the chassis116of the vehicle100. The strut176is configured to dampen vertical motion of the front suspension system148due to movement of the front wheel120as the vehicle100travels over terrain. The UCA152may be suitably configured, such as in the form of a J-arm, so as to facilitate coupling the strut176between the LCA156and the chassis116(seeFIG.1) of the vehicle100in lieu of being coupled between the UCA152and the chassis116. Moreover, it is contemplated that in some embodiments, the strut176may be coupled between the LCA156and the modular chassis128, without limitation, and without deviating beyond the scope of the present disclosure.

As best shown inFIG.2, a drive axle180is coupled between the front wheel120and the front differential and transaxle136,132. The drive axle180is configured to conduct torque from the transaxle132to the front wheel120and accommodate vertical pivoting motion of the front suspension system148in response to road conditions, as is straightforward to see upon comparingFIG.3andFIG.4. As best shown inFIG.3, the drive axle180includes a constant velocity (CV) joint184that is coupled with the spindle assembly144. The CV joint184enables uninterrupted torque transmission from the transaxle132to the front wheel120during vertical pivoting of the front suspension assembly148due to road conditions.

In the embodiment illustrated inFIGS.2-3, a steering rod188couples the spindle assembly144with the steering gear140disposed on the modular chassis128. The steering rod188may be coupled with the spindle assembly144by way of a steering rod-end joint192that is similar to the inboard UCA joints160. It is contemplated, therefore, that the steering rod-end joint192may be of a Heim-joint variety or may be of a bushing variety, as desired. As will be appreciated, the steering rod-end joint192allows vertical and horizontal rotational motion of the spindle assembly144during operation of the vehicle100.

Moreover, the steering rod-end joint192is coupled with the spindle assembly144forward of the drive axle180, thereby providing a leading-edge steering system to the vehicle100. Experimentation has demonstrated that the leading-edge steering system shown inFIGS.2-3advantageously decreases leverage of the front wheel120on the steering rod-end joint192and the steering rod188, thereby substantially eliminating bump steer that may occur due to forces exerted on the front wheel120by rough terrain. Details pertaining to rod-end joints are disclosed in above-mentioned U.S. patent application Ser. No. 15/625,692, which is entitled “Rod-End Front Suspension.” Further, details pertaining to leading-edge steering systems are disclosed in U.S. patent application Ser. No. 15/625,813, entitled “Leading-Edge Steering Assembly,” filed on Jun. 16, 2017, the entirety of which is incorporated herein by reference.

Turning again toFIG.2, the modular front drivetrain124may further include a braking system configured to enable a practitioner to slow the rotation rate of the front wheel120during operation of the vehicle100. In the illustrated embodiment ofFIGS.2-3, the brake system comprises a brake caliper196that is fastened onto the modular chassis128. A brake disc200is coupled to the drive axle180such that a periphery of the brake disc200passes within the brake caliper196. As will be recognized, when the practitioner depresses a brake pedal of the vehicle100the brake caliper196applies pressure to the brake disc200, thus slowing the rotation rate of the front wheel120. The brake caliper196may be cable operated or may be operated by way hydraulic lines. Although not shown inFIGS.2-3, the brake disc200may be coupled with a hub comprising the front differential136. In some embodiments, however, the brake disc200may be coupled with a constant velocity joint that is coupled with the hub of the front differential136. It is contemplated that the brake caliper196and the brake disc200may be incorporated into the modular front drivetrain124in a wide variety of configurations, without limitation, and without deviating beyond the scope of the present disclosure.

As disclosed hereinabove, the modular front drivetrain124comprises a modular chassis128that supports the transaxle132, the front differential136, the drive axle180and the front suspension system148, such that engine torque applied to the transaxle132is conveyed to the front wheel120. The modular chassis128also supports the steering gear140and the steering rod188, such that turning the steering gear140, by way of a steering wheel of the vehicle100, causes the front wheel120to articulate horizontally with respect to the modular chassis128. Further, the modular chassis128provides mounting points for the front suspension148that allow the front wheel120to move vertically from a low position (e.g., due to “maximal bounce”), shown inFIG.3, to a high position (e.g., due to “maximal bump”), shown inFIG.4. As such, the modular front drivetrain124is not limited to the specific configuration shown inFIGS.2-3, but rather the configuration of the modular front drivetrain124may be varied in accordance with the configuration of each of the components comprising the modular front drivetrain124, without limitation.

Moreover, the modular front drivetrain124generally may be varied in accordance with the specific type of vehicle100into which the modular front drivetrain124is to be implemented. It is contemplated that the modular front drivetrain124may be implemented in any of various off-road vehicles100, such as, by way of non-limiting example, Utility Task Vehicles (UTVs), Recreational Off-Highway Vehicles (ROVs), or Multipurpose Off-Highway Utility Vehicles (MOHUVs), without limitation. As such, the modular front drivetrain124is particularly well-suited for off-road racing applications, such as desert racing, short course racing, hill climbing, rallying, and the like.

In addition to the off-road applications discussed above, it is contemplated that, in some embodiments, the modular front drivetrain124may be incorporated into racing vehicles that are not necessarily intended for off-road racing. For example, the modular front drivetrain124may be incorporated into racing vehicles that may be used for any of formula racing, sports car racing, stock car racing, drag racing, touring car racing, production car racing, as well as amateur open-wheel racing applications, such as karting, and the like. In such applications, the modular front drivetrain124advantageously enables an entire drivetrain and suspension assembly to be quickly and easily replaced in the event of a part failure, unlike in the case of conventional racing vehicles that may be sidelined during a race due to the failure of an individual part comprising the drivetrain or the suspension.

In some embodiments, the strength and performance of an off-road vehicle chassis may be improved by implementing a front structural bulkhead. For example, in some embodiments, the chassis may be a welded-tube variety of chassis that includes a front portion and a rear portion that are joined to an intervening passenger cabin portion, wherein frontward stays and a bulkhead mount couple the front structural bulkhead to the front portion. Bulkhead mount pillars and a bulkhead mount crossmember may be used to couple the front structural bulkhead to the passenger cabin portion. In some embodiments, the front structural bulkhead includes a modular chassis for supporting drivetrain components that are operably coupled with front wheels of the vehicle. The front structural bulkhead may further include upper and lower mounting points configured to receive front suspension controls arms that allow the front wheels to move vertically due to the vehicle traveling over terrain.

FIG.5shows an exemplary embodiment of an off-road vehicle300that is particularly suitable for implementation of a front structural bulkhead in accordance with the present disclosure. The off-road vehicle300shown inFIG.5generally is of a Utility Task Vehicle (UTV) variety that seats up to four occupants, includes a roll-over protection system304, and may have a cab enclosure308. Rear wheels112of the off-road vehicle300may be operably coupled with a chassis116by way of a trailing arm suspension system320. Front wheels324may be operably coupled with the chassis116by way of a front suspension system328. It should be understood, however, that the front structural bulkhead disclosed herein is not to be limited to the specific off-road vehicle300shown inFIG.5, but rather the front structural bulkhead may be incorporated into a wide variety of vehicles, other than the off-road vehicle300ofFIG.5, without limitation.

FIG.6illustrates an exemplary embodiment of an off-road vehicle300that includes a front structural bulkhead340in accordance with the present disclosure. In the embodiment illustrated inFIG.6, the cab enclosure308and other body panels are removed to reveal the chassis116and the front structural bulkhead340comprising the off-road vehicle300. The chassis116generally is a welded-tube variety of chassis that includes a front portion328and a rear portion332that are joined to an intervening passenger cabin portion336. The passenger cabin portion336shown inFIG.6is configured to seat up to four occupants. A front canopy344and a rear canopy348are configured to impart structural integrity to the chassis116and to provide a roll-over protection system304to occupants of the off-road vehicle300.

The front portion328generally is configured to support various components comprising the off-road vehicle300, such as, by way of non-limiting example, the front suspension328and the front structural bulkhead340. The rear portion332is configured to support the rear suspension320of the off-road vehicle300, such as rear trailing arms, as well as support various drivetrain components, shown inFIG.5, such as an engine, a transaxle, a rear differential, an engine, and the like.

As will be appreciated, the passenger cabin portion336, as well as the front and rear portions328,332, are configured to distribute loading forces arising during operation of the vehicle300so as to resist damage to components comprising the vehicle300and to protect occupants riding within the vehicle300. To this end, the front canopy344and the rear canopy348that are configured to be coupled with the chassis116. More specifically, the front canopy344is configured to be coupled with the front portion328, and the rear canopy348is configured to be coupled with the rear portion332. Further, the front canopy344is configured to be coupled with the rear canopy348. It should be recognized, therefore, that the front canopy344and the rear canopy348are configured to contribute to the overall integrity of the entire chassis116.

As mentioned above, the front portion328generally supports various components comprising the off-road vehicle300, including the front suspension328and the front structural bulkhead340. As shown inFIG.7, the front portion328may be defined by a front hoop352at a top of the front portion328and a bulkhead mount356at a bottom of the front portion328. Frontward stays360attach the front hoop352to the bulkhead mount356. The bulkhead mount356is configured to be coupled with the front structural bulkhead340(seeFIG.6), which supports at least the front suspension328and includes a steering gear, a front differential, and the like. In some embodiments, the bulkhead mount356may be coupled with a modular front drivetrain that supports an entire front drivetrain and suspension assembly. In such applications, the modular front drivetrain advantageously enables the entire drivetrain and suspension assembly to be quickly and easily replaced in the event of a part failure, unlike in the case of conventional off-road vehicles that may be sidelined during a race due to the failure of an individual part comprising the drivetrain or the suspension. The frontward stays360operate to couple the modular front drivetrain to the chassis116. Opposite of the frontward stays360, the front hoop352is joined to opposite ends of a dash bar364and hinge pillars368comprising the passenger cabin portion336.

With continuing reference toFIG.7, a front strut crossmember372comprises a portion of the front hoop352between the driver-side and passenger-side of the front hoop352. The front strut crossmember372provides a means for coupling front struts376to the chassis328, as shown inFIG.6. As best shown inFIG.8, front strut braces380are disposed between the front strut crossmember372and the dash bar364. The front strut braces380are configured to reinforce the front strut crossmember372, such that loading on the front strut crossmember372by the front struts376and the bulkhead340is distributed to the dash bar364. As shown inFIG.10, one end of each front strut brace380is coupled to a location of a front strut crossmember372that is above a top mount384of each front strut376(seeFIG.6). Further, each front strut brace380is coupled to the front strut crossmember372near the joining of the forward stays360and the front strut crossmember372. As such, forces on the front strut crossmember372by the front struts376and the bulkhead340, during operation of the vehicle300, are shared by the dash bar364.

With continuing reference toFIG.7, the floor hoop388generally defines a floor of the passenger cabin portion336. Longitudinal floor bars392and crossmembers396coupled with the floor hoop388impart structural strength to the passenger cabin portion336and facilitate coupling various components to the floor of the passenger cabin portion336. At a front-most position of the floor hoop388bulkhead mount pillars400extend vertically to a bulkhead mount crossmember404disposed between the hinge pillars368. As best shown inFIGS.8-9, the bulkhead mount pillars400and the bulkhead mount crossmember404serve to support a rear portion of the bulkhead340. Further, a brace408extends from a midpoint of the bulkhead mount crossmember404to the dash bar364. As such, loading on the bulkhead mount crossmember404, during operation of the vehicle300, is distributed throughout the chassis116.

FIG.11illustrates a perspective view of an exemplary embodiment of a front structural bulkhead340that may be incorporated into an off-road vehicle300in accordance with the present disclosure. The front structural bulkhead340includes a modular chassis412that may support any one or more of a transaxle, a front differential, a steering gear416, a braking system, and the like, that are operably coupled with the front wheels324by way of the front suspension system328, as shown inFIGS.5-6. Further, the modular chassis412provides mounting points for the front suspension328, in lieu of conventional mounting points that comprise portions of the chassis116of the vehicle300. In particular, the modular chassis412includes lower mounting points420for coupling with lower control arms424(seeFIG.12) comprising the front suspension328. Further, the modular chassis412includes upper mounting points428for coupling with upper control arms432comprising the front suspension328. It is to be understood, therefore, that the front structural bulkhead340comprises a single drivetrain/suspension assembly that may be installed onto and removed from the vehicle300, unlike a conventional drivetrain and suspension that comprise multiple components that must be individually assembled onto the chassis116of the vehicle300. Further, the front structural bulkhead340integrates the transaxle, the front differential, the steering gear416, and the front suspension system into the chassis116.

It is contemplated that the modular chassis412may include a braking system configured to enable a practitioner to slow the rotation rate of the front wheel324during operation of the vehicle300. For example, in some embodiments, brake calipers may be fastened onto the modular chassis412such that brake discs coupled to drive axles of the vehicle300pass within the brake caliper. Thus, when the practitioner depresses a brake pedal of the vehicle300the brake calipers apply pressure to the brake discs, slowing the rotation rate of the front wheels324. The brake calipers may be cable operated or may be operated by way hydraulic lines. Although not shown herein, the brake discs may be coupled with a hub comprising the front differential. In some embodiments, however, the brake discs may be coupled with constant velocity joints that are coupled with the hub of the front differential. It is contemplated that the brake calipers and the brake discs may be incorporated into the front structural bulkhead340in a wide variety of configurations, without limitation, and without deviating beyond the scope of the present disclosure.

As disclosed hereinabove, the front structural bulkhead340also supports the steering gear416and steering rods436(seeFIG.12), such that turning the steering gear416, by way of a steering wheel of the vehicle300, causes the front wheels324to articulate horizontally with respect to the front structural bulkhead340. Further, the upper and lower mounting points428,420comprising the modular chassis412are configured to allow the front wheels324to move vertically from a low position (e.g., due to “maximal bounce”) to a high position (e.g., due to “maximal bump”). As such, the front structural bulkhead340is not limited to the specific configuration shown inFIG.11, but rather the configuration of the front structural bulkhead340may be varied in accordance with the configuration of each of the components comprising the front suspension system328, without limitation.

Moreover, the front structural bulkhead340generally may be varied in accordance with the specific type of vehicle300into which the front structural bulkhead340is to be implemented. It is contemplated that the front structural bulkhead340may be implemented in any of various off-road vehicles300, such as, by way of non-limiting example, Utility Task Vehicles (UTVs), Recreational Off-Highway Vehicles (ROVs), or Multipurpose Off-Highway Utility Vehicles (MOHUVs), without limitation. As such, the front structural bulkhead340is particularly well-suited for off-road racing applications, such as desert racing, short course racing, hill climbing, rallying, and the like.

FIG.12illustrates a close-up view of an exemplary embodiment of the front structural bulkhead340incorporated into the off-road vehicle300, according to the present disclosure. As shown inFIG.12, an upper control arm (UCA)432and a lower control arm (LCA)424comprising the front suspension system328couple the front wheels324(seeFIGS.5-6) with the front structural bulkhead340. The UCA432comprises two inboard UCA joints440that couple the UCA432to upper mounting points428of the front structural bulkhead340and an outboard UCA joint (not shown) that couples the UCA432to a spindle assembly444(seeFIGS.5-6). The LCA424includes two inboard LCA joints448that couple the LCA424to the front structural bulkhead340and an outboard LCA joint (not shown) that couples the LCA424to the spindle assembly444.

As will be recognized, the UCA and LCA432,424generally are of a double wishbone variety of suspension that facilitates vertical motion of the front wheels324during travel over terrain, as well as facilitating horizontal turning of the front wheels324during steering of the vehicle300by way of the steering gear416(seeFIG.11). The UCA and LCA432,424further facilitate controlling various parameters affecting the orientation of the front wheels324with respect to the off-road vehicle300, such as, by way of non-limiting example, camber angle, caster angle, toe pattern, roll center height, scrub radius, and scrub. Further, a steering rod452coupling each front wheel324(seeFIGS.5-6) with the steering gear416mounted on the front structural bulkhead340allows for vertical movement and horizontal turning of the front wheels324during operation of the vehicle300.

In addition to the off-road applications discussed above, it is contemplated that, in some embodiments, the front structural bulkhead340may be incorporated into racing vehicles that are not necessarily intended for off-road racing. For example, the front structural bulkhead340may be incorporated into racing vehicles that may be used for any of formula racing, sports car racing, stock car racing, drag racing, touring car racing, production car racing, as well as amateur open-wheel racing applications, such as karting, and the like, without limitation.

While the modular front drivetrain and methods have been described in terms of particular variations and illustrative figures, those of ordinary skill in the art will recognize that the modular front drivetrain is not limited to the variations or figures described. In addition, where methods and steps described above indicate certain events occurring in certain order, those of ordinary skill in the art will recognize that the ordering of certain steps may be modified and that such modifications are in accordance with the variations of the modular front drivetrain. Additionally, certain of the steps may be performed concurrently in a parallel process, when possible, as well as performed sequentially as described above. To the extent there are variations of the modular front drivetrain, which are within the spirit of the disclosure or equivalent to the modular front drivetrain found in the claims, it is the intent that this patent will cover those variations as well. Therefore, the present disclosure is to be understood as not limited by the specific embodiments described herein, but only by scope of the appended claims.