Patent Application
20060254840
The present invention generally relates to road vehicles, off-road vehicles, or all-terrain vehicles (ATVs) suitable for traveling over even or uneven terrain in various environments. The present invention more particularly relates to vehicles such as, for example, automotive vehicles, recreational vehicles, snowmobiles, agricultural vehicles, utility vehicles, construction vehicles, military vehicles, or robotic vehicles.
A “zero turn” (ZT) vehicle, as is commonly known in the art, will in some embodiments typically include, for example, a frame, a power source, a body, a primary axle assembly, two drive wheels, and two dolly wheel assemblies. The power source is commonly mounted to the central or rear portion of the frame and typically includes, for example, at least one engine or motor. The body, too, is mounted to the frame and is suitable for carrying a human load, for example, the vehicle operator, and an object load as well. The primary axle assembly is also mounted to the frame. In particular, the primary axle assembly is typically mounted to the rear portion of the frame such that the primary axle assembly is aligned substantially orthogonal to the length of the frame. The two drive wheels, in turn, are rotatably mounted on the ends of the primary axle assembly such that the drive wheels are aligned substantially in parallel and are in mechanical communication with the power source. To facilitate ease in vehicle movement and travel, the two dolly wheel assemblies, lastly, are typically mounted to the front portion of the frame. In such a configuration, the two drive wheels are capable of facilitating both driving and moving interaction with the ground. The two dolly wheel assemblies, however, merely cooperate with the two drive wheels in generally maintaining the overall balance of the vehicle as the vehicle travels over the ground.
As is uniquely characteristic of a ZT vehicle, the two drive wheels are particularly rotatably mounted to the primary axle assembly so that they each have independent drive capability. That is, both the speed and the direction of rotation of the two drive wheels are controlled independently from each other as dictated by the vehicle operator through the delivery of power from the power source. In this way, steering the vehicle in a desired direction of travel is successfully accomplished by the vehicle operator through independently varying, as necessary, the rotational speed and direction of each drive wheel. As a result, a ZT vehicle is much more highly maneuverable as compared to automotive vehicles incorporating more traditional linkage or rack-and-pinion front axle steering systems. In particular, a ZT vehicle is virtually capable of “turning on a dime” and therefore has an overall vehicle turning radius of zero. The two ground-interacting dolly wheels associated with the two dolly wheel assemblies are each swivel mounted to the frame and rotatable such that they both merely cooperate with the two drive wheels in maintaining the overall balance of the vehicle as the vehicle travels over the ground. Thus, the two ground-interacting dolly wheels themselves are, by design, not capable of being directly steered by the vehicle operator.
Although a ZT vehicle has the inherent advantage and desirable characteristic of having such zero turn capability, a ZT vehicle also has some inherent disadvantages and undesirable characteristics as well. For example, if, as opposed to traveling directly up or directly down the side of a hill, a ZT vehicle is instead traveling across the side of a hill, the front portion of the vehicle naturally tends to pull the front end of the vehicle sideways and downhill. Such a tendency is due in respective part to three reasons. First, the typical ZT vehicle, as described hereinabove, is commonly weighted at its front end in order to maintain vehicle stability when driving up steep inclines. Second, the typical ZT vehicle, as described hereinabove, includes two ground-interacting dolly wheels mounted to the front portion of the frame that provide no directional stability for the front end of the vehicle. Third, since the “uphill” drive wheel of the vehicle naturally has less traction than the “downhill” drive wheel of the vehicle due to the incline of the hill effectively shifting more of the vehicle weight to the downhill drive wheel, the uphill drive wheel is prone to losing traction and therefore slipping. When such slipping occurs, the directional stability normally provided by the uphill drive wheel is lost, thereby causing the front end of the vehicle to be gravitationally pulled sideways and downhill.
To help correct the problem associated with traveling across a hillside, engineers commonly prescribe designs for ZT vehicles wherein most of the overall weight of the vehicle is shifted further back along the length of the frame. In doing so, most of the vehicle weight is thereby particularly centered just in front of and over the primary axle assembly. As a result, improved traction of the two drive wheels mounted on the ends of the primary axle assembly is realized and less pull at the front end of the vehicle is also realized whenever the vehicle travels across a hillside. However, a problem sometimes arises when the ZT vehicle attempts to travel directly up a steep hill. In particular, if the incline of a hill is sufficiently severe, the front end of the ZT vehicle comes off the ground as the overall weight and center of gravity of the vehicle shifts rearward and beyond the points of contact between the two drive wheels and the ground. Furthermore, even if the incline of a hill is not so severe, a sudden burst of acceleration by the ZT vehicle as initiated by a vehicle operator while driving the vehicle also frequently causes the front end of the vehicle to come off the ground. In extreme cases of these two types of situations, the front end of the ZT vehicle sometimes comes off the ground to the extent that the vehicle is altogether upended.
In order to remedy the problem associated with traveling directly up a steep hill, most designs for ZT vehicles include either a “wheelie bar” (sometimes simply called a “roller bar”) or a skid plate. Such a wheelie bar or skid plate is mounted to the rear end of the vehicle frame to thereby prevent the vehicle from being altogether upended whenever the front end of the vehicle comes off the ground. The inclusion of one or both such remedial fixtures is reasonably effective in facilitating vehicle travel up a hill in cases where the front end of the vehicle infrequently and merely momentarily comes off the ground. However, such remedial fixtures have proven to be undesirable in cases where the front end of the vehicle comes off the ground for prolonged periods of time, for the fixtures in such cases give rise to drag that significantly inhibits rather than facilitates uphill travel.
To help eliminate the problems associated with traveling both across and up a hill, some engineers have designed ZT vehicles that include a manually adjustable ballast system. When used, such an adjustable ballast system has to, first of all, be manually preset. Once preset, the ballast system can then be effectively utilized onboard the vehicle, especially when traveling over long stretches of anticipated or known terrain with consistent topography or grade characteristics. However, such a manually adjustable ballast system has proven to be largely inconvenient to use when traveling over unanticipated or unknown terrain with extreme and everchanging topography or grade characteristics. Furthermore, such a manually adjustable ballast system has also proven to be largely inconvenient to use whenever frequent and significant changes in the human load and/or the object load onboard the vehicle are made.
In an attempt to correct the problem associated with traveling over extreme and everchanging terrain, engineers have designed ZT vehicles that include two elongated ground-interacting track assemblies. The two track assemblies are mounted to the frame of the vehicle such that the two drive wheels, or drives associated therewith, are engaged within the two track assemblies to thereby facilitate both driving and moving interaction of the two track assemblies with the ground. In such a configuration, dolly wheel assemblies are typically not included. Although such elongated track assemblies are effective in improving the overall fore-aft stability of the vehicle when traveling over extreme and everchanging terrain, the inherent elongated nature of the track assemblies undesirably limits, in some situations, the zero turn capability of the vehicle. In addition, given the typical variation in fore-aft (i.e., front-to-back) loading of a ZT vehicle, each elongated track assembly often fails to properly interact with the ground in an even pressure-distributed manner along its respective length, thereby undesirably negating a characteristic advantage of utilizing such elongated track assemblies on terrain with, for example, sand or snow.
To remedy the problem associated with designing a ZT vehicle that successfully travels over extreme and everchanging terrain without limiting the zero turn capability of the vehicle, some engineers have designed a ZT vehicle that includes a gyroscopic sensor system. In particular, the vehicle includes a system of multiple gyroscopic sensors electrically connected to one or more electronic controllers. The electronic controllers, in turn, are electrically connected to drive wheel motors which themselves are in mechanical communication with the two drive wheels. In such a configuration, the gyroscopic sensors continuously sense the attitude or balance condition of the vehicle as the vehicle travels over everchanging terrain. While doing so, the gyroscopic sensors also continuously communicate electrical vehicle attitude or balance condition information signals to the electronic controllers. The electronic controllers, in turn, then process the electrical vehicle attitude information signals, generate electrical control signals based on the vehicle attitude information, and communicate the electrical control signals to the drive wheel motors. The drive wheel motors then mechanically operate the two drive wheels in compliance with the electrical control signals received from the electronic controllers. In this manner, the gyroscopic sensor system attempts to continuously maintain the fore-aft stability and overall balance of the vehicle by regulating the fore-aft driving rotation of the two drive wheels underneath the vehicle such that the overall weight and/or load of the vehicle is generally centered and maintained over the primary axle assembly and drive wheels. Although such a ZT vehicle with gyroscopic sensor system is reasonably effective in maintaining vehicle balance under most conditions, such is only marginally effective under conditions of reduced traction. For example, if an area of ground on a hillside is significantly covered with sand, loose gravel, mud, water, snow, or ice, a ZT vehicle with gyroscopic sensor system sometimes has difficulty in maintaining its balance while traveling thereon. Such difficulty is due to the fact that good traction necessary for drive wheel movement to quickly correct any vehicle imbalance is not always available under such reduced traction conditions.
In light of the above, there is a present need in the art for a vehicle and/or a vehicle system that (1) successfully maintains vehicle balance when traveling directly up a hill, (2) successfully maintains vehicle balance when traveling across a hillside, (3) successfully maintains vehicle balance even when a vehicle operator attempts rapid acceleration or sudden braking, (4) successfully maintains vehicle balance when traveling over terrain with extreme and everchanging topographies, (5) successfully maintains vehicle balance and optimizes traction even when there are significant and frequent changes in human load and/or object load onboard the vehicle, (6) successfully maintains vehicle balance even under reduced traction conditions, (7) does not unnecessarily limit maximum zero turn capability in a ZT vehicle, and (8) is successfully applicable to both ZT vehicles and non-ZT vehicles as well.
The present invention provides a vehicle capable of traveling over uneven ground or terrain. In one practicable embodiment, the vehicle includes a body, a frame, a pair of front wheels, an adjustable axle assembly, two pairs of rear wheels, and an actuation system. The body is mounted to the frame, and the frame has front and rear ends with a fore-aft axis extending therebetween. The front wheels are rotatably mounted opposite each other at the front end of the frame, and the adjustable axle assembly is mounted at the rear end of the frame substantially orthogonal to the fore-aft axis. The wheels in each of the two pairs of rear wheels are rotatably mounted opposite each other at the ends of the adjustable axle assembly. The actuation system is capable of mechanically moving the adjustable axle assembly to thereby adjust the fore-aft positions of the rear wheels relative to the frame. In this same or other embodiment, the vehicle may further include a second actuation system. The second actuation system is capable of mechanically rotating the adjustable axle assembly to thereby adjust the heights of the rear wheels relative to the frame.
In still another practicable embodiment, the vehicle may include a body, a frame, at least one ski, an adjustable axle assembly, a pair of drive track assemblies, a first actuation system, and a second actuation system. The body is mounted to the frame, and the frame has front and rear ends with a fore-aft axis extending therebetween. Each ski is mounted at the front end of the frame, and the adjustable axle assembly is mounted at the rear end of the frame substantially orthogonal to the fore-aft axis. The drive track assemblies are mounted opposite each other at the ends of the adjustable axle assembly. The first actuation system is capable of mechanically moving the adjustable axle assembly to thereby adjust the fore-aft position of the drive track assemblies relative to the frame. The second actuation system is capable of mechanically rotating the adjustable axle assembly to thereby adjust the pitch of the drive track assemblies relative to the frame.
Furthermore, it is believed that still other embodiments of the present invention will become apparent to those skilled in the art when the detailed descriptions of the best modes contemplated for practicing the invention, as set forth hereinbelow, are reviewed in conjunction with the appended claims and the accompanying drawing figures.
The present invention is described hereinbelow, by way of example, with reference to the following drawing figures.
To facilitate a proper understanding of the present invention, a list of parts and features highlighted with alphanumeric designations in
As illustrated in
In addition to both the frame 22 and the body 60, the vehicle 20A also includes a first embodiment 131A of the actively adjustable axle system 131 with a pair of rear drive wheels 56L and 56R. The actively adjustable axle system 131A itself includes a first embodiment 86A of the adjustable axle assembly 86, a first embodiment 90A of the actuation system 90, and the electronic controller 96. The adjustable axle assembly 86A, as particularly illustrated in
Given the adjustable axle assembly 86A as configured, the two rear drive wheels 56L and 56R are rotatably suspended from the two swing arms 110L and 110R proximate the distal ends 114L and 114R thereof. As particularly illustrated in
To facilitate adjustment of the adjustable axle assembly 86A, the actuation system 90A includes a pair of telescoping cylinders 126L and 126R serving as left and right actuators. As particularly illustrated in
In addition to the frame 22, the body 60, the actively adjustable axle system 131A, and the two rear drive wheels 56L and 56R, the vehicle 20A further includes a pair of dolly (or caster) wheel assemblies 46L and 46R. The dolly wheel assemblies 46L and 46R are mounted to the front portion of the frame 22 such that they cooperate with the two rear drive wheels 56L and 56R in generally maintaining the overall balance of the vehicle 20A as the vehicle 20A travels over the ground 103. As particularly illustrated in
As illustrated in
Also, as illustrated in
As particularly suggested in
Moreover, as illustrated in
Furthermore, as illustrated in
During operation, as the vehicle 20A travels over the ground 103, the electronic controller 96 receives electrical vehicle attitude information signals from the attitude sensors 102L and 102R, electrical load information signals from the load sensors 106L, 106R, and 106B, and electrical axle assembly position information signals from the position sensors 108L and 108R on a substantially continuous basis. As all of these electrical information signals are received, the electronic controller 96 promptly processes the electrical information signals. In doing so, the electronic controller 96 thereby attempts to actively determine and monitor the position of the center of gravity 100 of the vehicle 20A together with its cumulative onboard load in relation to the ground contact points of both the two dolly wheels 48L and 48R and also the two rear drive wheels 56L and 56R.
Given that the vehicle 20A in this particular embodiment is a ZT vehicle, the vehicle 20A and its component parts are specifically dimensioned, weighted, and assembled such that the overall center of gravity 100 of the vehicle 20A together with its load is naturally predisposed to being well behind the ground contact points of the dolly wheels 48L and 48R and just in front of and over the ground contact points of the two rear drive wheels 56L and 56R when the two rear drive wheels 56L and 56R are in a position forward of the midpoint of the adjustable axle assembly movement range and the vehicle 20A is traveling over ground 103 that is substantially level. In light of such purposeful dimensioning and center of gravity predispositioning, when the vehicle 20A is traveling over substantially level ground and the electronic controller 96 actively determines that the center of gravity 100 of the vehicle 20A together with its cumulative onboard load is safely situated behind the ground contact points of the two dolly wheels 48L and 48R and also in front of the ground contact points of the two rear drive wheels 56L and 56R, the electronic controller 96 will accordingly generate situation-specific electrical control signals and communicate the electrical control signals to the actuation system 90A. In response to the electrical control signals, the actuation system 90A will then mechanically adjust (i.e., pivot) the adjustable axle assembly 86A only if and as needed to thereby position the two rear drive wheels 56L and 56R in an optimal retracted (forward) fore-aft position as generally illustrated in
In situations, for example, where a vehicle operator fully anticipates traveling up a steep hill or firmly believes that the electronic controller 96 is receiving improper electrical information signals from a suspected malfunctioning sensor, the vehicle operator may opt to utilize the operator control panel 98 to manually enter operator preference input regarding his choice for moving the pair of rear drive wheels 56L and 56R into a particular fore-aft position. Once the vehicle operator enters his particular fore-aft position preference, electrical operator preference input information signals are communicated to the electronic controller 96. In response to receiving such electrical operator preference input information signals, the electronic controller 96 then ignores all other electrical information signals and promptly communicates electrical control signals to the actuation system 90A in accordance with the particular preference of the vehicle operator. As a result, the fore-aft position of the pair of rear drive wheels 56L and 56R is ultimately adjusted to maintain the fore-aft stability of the vehicle 20A according to the vehicle operator's best judgment. Thus, in this way, a vehicle operator can utilize the operator control panel 98 to manually override the actively adjustable axle system 131A of the vehicle 20A as desired and as necessary.
In summary, the first embodiment 20A of the vehicle 20 according to the present invention realizes many advantages over other off-road or all-terrain vehicles, and particularly ZT vehicles, commonly in use today. In particular, with its purposeful dimensioning, weight distribution, and predisposed center of gravity along with the actively adjustable axle system 131A, the vehicle 20A according to the present invention (1) successfully maintains its balance when traveling directly up a hill, (2) successfully maintains its balance when traveling across a hillside, (3) successfully maintains its balance even when a vehicle operator attempts rapid acceleration or sudden braking, (4) successfully maintains its balance when traveling over terrain with extreme and everchanging topographies, (5) successfully maintains its balance and optimizes traction even when there are significant and frequent changes in human load and/or object load onboard, (6) successfully maintains its balance even under reduced traction conditions, (7) is not unnecessarily limited in maximum zero turn capability when suited for use as a zero turn (ZT) vehicle, and (8) may successfully be adapted or suited for use as either a ZT vehicle or a non-ZT vehicle.
This concludes the detailed description of both the structure and operation of the first embodiment 20A of the vehicle 20 according to the present invention.
An alternative embodiment 131B of the actively adjustable axle system 131 is illustrated in
Another alternative embodiment 131C of the actively adjustable axle system 131 is illustrated in
Still another embodiment 131D of the actively adjustable axle system 131 is illustrated in
In cooperation with such an actuation system 90B, the cross arm assembly 116 of the adjustable axle assembly 86A has a third embodiment 116C, as particularly illustrated in
Within such a configuration as depicted in
A slightly alternative embodiment 20B of the vehicle 20 is illustrated in
As clearly demonstrated in
Another alternative embodiment 20C of the vehicle 20 is illustrated in
While the present invention as described hereinabove was initially conceived in response to particular difficulties experienced with the performance and design of ZT vehicles, it is to be understood that the present invention is largely relevant and applicable to non-ZT vehicles as well. That is, many of the basic inventive principles implemented herein to improve the overall performance and design of ZT vehicles are applicable to many non-ZT vehicles as well. In particular, upon reading this invention disclosure, it is believed that one skilled in the art would readily realize that the inventive principles taught herein, for example, (1) actively determining the center of gravity of a vehicle with its cumulative onboard load to thereby maintain vehicle balance, (2) actively responding to shifts in vehicle attitude while the vehicle travels over extreme and everchanging terrain to thereby maintain vehicle balance, (3) actively responding to significant and frequent changes in human load and/or object load onboard the vehicle to thereby maintain vehicle balance, and (4) actively extending and/or retracting a two-wheeled axle of the vehicle as necessary to thereby optimize both vehicle maneuverability and vehicle balance, may also be applied to many non-ZT vehicles as well.
While having independent front or rear 2-wheel drive is primarily characteristic of ZT vehicles, it is to be understood that a vehicle pursuant to the present invention may alternatively have dependent front or rear 2-wheel drive capability, 4-wheel drive capability, or even all-wheel drive capability. In addition, with regard to suspension systems, a vehicle pursuant to the present invention may have an independent, non-independent, or semi-independent suspension system. Also, with regard to suspension system springs, a vehicle pursuant to the present invention may, as an alternative to coil springs, instead include leaf springs, air springs, or torsion bar springs. Moreover, with regard to vehicle steering systems, a vehicle pursuant to the present invention may, as an alternative to having two dolly wheels and two wheels with independent 2-wheel drive, instead have two largely non-steerable wheels and two wheels directly steerable with a traditional linkage or rack-and-pinion steering system. Furthermore, with regard to the actuation system, it is to be understood that many different types of actuators may alternatively be utilized on a vehicle pursuant to the present invention, including, for example, hydraulic, electric, pneumatic, or mechanical linkage type actuators, or even combinations thereof. Still further, any actuation system incorporating one or more of such actuators may optionally be designed to adjust the fore-aft positions of vehicle wheels either together in pairs or independently and individually pursuant to the present invention.
In summary, the vehicle with actively adjustable axle system for traveling over uneven terrain with a load, as described hereinabove within its various preferred embodiments according to the present invention, realizes many advantages over other off-road or all-terrain vehicles commonly in use today. In particular, the vehicle according to the present invention (1) successfully maintains its balance when traveling directly up a hill, (2) successfully maintains its balance when traveling across a hillside, (3) successfully maintains its balance even when a vehicle operator attempts rapid acceleration or sudden braking, (4) successfully maintains its balance when traveling over terrain with extreme and everchanging topographies, (5) successfully maintains its balance and optimizes traction even when there are significant and frequent changes in human load and/or object load onboard, (6) successfully maintains its balance even under reduced traction conditions, (7) is not unnecessarily limited in maximum zero turn capability when suited for use as a zero turn (ZT) vehicle, and (8) may successfully be adapted or suited for use as either a ZT vehicle or a non-ZT vehicle.
In general, a vehicle having a single primary axle with independent drive and speed control of each of the two wheels provides maneuverability known by those knowledgeable in the art as zero turn capability. Such a vehicle provides significant advantages in maneuverability, but has characteristics of operation that are unique to such a vehicle having a single axle that is utilized for both traction and steering control. This vehicle, as discussed hereinabove, has some disadvantages, including when operated on the sides of hills. This is particularly true when a heavier weighting of the front of the vehicle, which is generally supported by dolly wheels that provide no directional stability, results in a tendency for the heavier front weight to pull the front of the vehicle downhill. With the additional characteristic of the vehicle having less traction on the uphill drive wheel due to the side slope effectively shifting weight of the vehicle to the downhill drive tire, slippage of this uphill tire allows this undesired turning of the heavier front of the vehicle weight down the hill. In the case of a single axle lower drive wheel, the single tire's single point of contact with the ground offers little resistance to rotating in the horizontal plane. The same rotational result can occur when braking rapidly with the uphill wheel having less traction than the downhill wheel, resulting in skidding of the uphill wheel before that of the downhill wheel, thus effectuating vehicle rotation or unwanted steering since the front dolly wheels offer no resistance to the rotation of the vehicle.
Vehicle embodiments discussed hereinabove provide at least one solution for addressing both vehicle balance and tractive capability, which has a direct impact on steering stability in the conditions mentioned above. In accordance with this solution, the additional drive and steering capability is achieved with the vehicle weight being balanced on the single drive axle, this being achieved by the movement of the drive axle for the centering of the vehicle balance over this single axle. A further “mechanical” mechanism for rotational (or steering) stability of this zero-turn vehicle would further the vehicle's capabilities in extreme operating conditions. For example, another set of tires that operate in the same fore-aft axis, forward or rearward of the single tire, would provide assistance both through additional traction and the mechanical effect of placing a second point on the ground, thereby eliminating the single point rotational center.
A rigid frame four-wheel drive vehicle, such as a skid-steer loader, that is made to turn, including zero-turn operation, by varying the rotation and speed of the right and left drive wheels causes skidding of the tires at contact with the ground. In contrast, a vehicle having what is known in the industry as zero-turn capability by means of a single drive axle and having front caster wheels, is highly maneuverable without the wheels causing scuffing on the ground. This type of vehicle has little, or no, skidding of the turning wheels that generate directional change. While the four-wheel drive skid-steer vehicles are also highly maneuverable, they either have little fore-aft stability at high speed due to a short wheelbase intended to minimize the skidding and scuffing, or the tires are spread as far apart as possible for stability and thus the vehicle has excessive scuffing and skidding during rotational turning. General designs of these vehicles attempt a balance of the two conflicting criteria for a medium result, thereby achieving neither high-speed fore-aft stability nor non-scuff rotational turning.
A vehicle that could effectively combine the characteristics of both skid-steer and spin-steer vehicles would be able to have greater fore-aft stability, particularly at high speeds, and also less scuffing of the ground at the points of contact of the steering tires. If a further addition to this combination included the ability of the four-wheel drive mechanism to be actively moved relative to the vehicle weight in all operations and loading of the vehicle, the wheel spacing could be reduced to thereby reduce scuffing during zero-turning with the weight balanced over the four-wheel drive mechanism, and the overall wheelbase relative to the front stabilizing wheels (for example, dolly wheels) could be lengthened during high-speed travel for greater fore-aft stability and ride comfort.
In general, an ideal stability for high-speed driving can be achieved via direct steering of the front wheels of a vehicle and also the vehicle having a long wheelbase. However, such a configuration is generally not conducive to rapid or smooth zero-turn operation. If, however, the steering wheels were off the ground during any such radical zero-turning operation, these wheels would not cause drag or skidding.
Furthermore, a vehicle with a drive track assembly that is able to be installed as a module in place of dual drive tires, and possible use of steering skis in the front of the vehicle, would also utilize the advantages achieved with the shifting dual drive axles, with improved fore-aft stability and hillside steering stability over that of a zero turn vehicle utilizing tires, much the same as with fore-aft dual tires as described above. However, front skis in a standard snowmobile configuration generally do not allow zero-turn capability. Without a front ski stabilizing the vehicle's fore-aft dimension, a long track helps provide such desired fore-aft stability, while a short track is of distinct advantage for a vehicle of zero turn capabilities. Thus, similar to the discussion hereinabove, a track assembly that is able to move under the vehicle for balance, utilized in conjunction with the capability of rotation of the track chassis relative to the vehicle for the lifting of the front of the vehicle to get the front ski(s) off the ground, allows zero-turn capability to be most fully realized on a vehicle. A dolly wheel, or front drive wheel, positioned in front of the shifting oscillating track assembly units can also have advantages in all-terrain use, with the track chassis rotating relative to the vehicle so as to allow lifting of such a front wheel configuration, thereby effecting complete zero-turn capability.
Discussed hereinabove is a personal zero-turn vehicle system that provides vehicle balance over one drive axle. In this vehicle, balance is maintained by a system of gyroscopic sensors in communication with an electronic controller in communication with drive wheel motors such that the wheels rotate and drive such that they stay under the vehicle's overall load. This system, however, sometimes may suffer in extreme conditions of limited traction, such as on snow and/or ice, where instantaneous traction necessary for drive wheel movement to correct any balance changes is not always available.
Thus, it would be ideal for a vehicle to have balancing capabilities that implement the advantageous features of the above-described zero-turn vehicles, but also with further enhanced traction capability and mechanical stability that allows all-weather, all-terrain, and all-speed capability.
Though the front wheels 248L and 248R of the vehicle 20D may be non-steerable wheels such as dolly wheels or caster wheels, the front wheels 248L and 248R are preferably steerable to thereby enhance vehicle stability and balance when the vehicle 20D is traveling at a high rate of speed. Both the first pair of rear wheels 256L and 256R and the second pair of rear wheels 356L and 356R are preferably independently operable drive wheels to thereby facilitate skid-steer turning that approximates zero turn capability.
As illustrated in the block diagram of
In the same or other embodiment, the vehicle 20D may include an electronic controller 296 mounted to the body 60 and electrically connected to one or more rotary actuators 226L and 226R of the second actuation system 390. In such a configuration, the electronic controller 296 is capable of communicating electrical control signals to the second actuation system 390 to thereby permit free and oscillatory rotation of the adjustable axle assembly 286 as necessary to help maintain all front wheels 248L and 248R and all rear wheels 256L, 256R, 356L, and 356R on the ground. In this same or other configuration, the electronic controller 296 may alternatively be capable of communicating electrical control signals to the second actuation system 390 to thereby adjust the heights of the first and second pairs of rear wheels as necessary to actively help maintain all front wheels 248L and 248R and all rear wheels 256L, 256R, 356L, and 356R on the ground. Also, in this same or other configuration, the electronic controller 296 may alternatively be capable of communicating electrical control signals to the second actuation system 390 to thereby adjust the heights of the first and second pairs of rear wheels as necessary to lift and actively help maintain one of either the pair of front wheels 248L and 248R, the first pair of rear wheels 256L and 256R, or the second pair of rear wheels 356L and 356R off the ground. Furthermore, in this same or other configuration, the electronic controller 296 may alternatively be capable of communicating electrical control signals to the second actuation system 390 to thereby adjust the heights of the first and second pairs of rear wheels as necessary to actively help maintain the body 60 at a pre-selected pitch as desired, for example, by a driver or operator of the vehicle 20D.
In a fifth practicable embodiment 20E (not illustrated) of the vehicle 20 somewhat similar to the third embodiment 20C discussed earlier hereinabove, the vehicle 20E may alternatively include a body, a frame, at least one ski, an adjustable axle assembly, a pair of drive track assemblies, a first actuation system, and a second actuation system. The body is mounted to the frame, and the frame has front and rear ends with a fore-aft axis extending therebetween. Each ski is mounted at the front end of the frame, and the adjustable axle assembly is mounted at the rear end of the frame substantially orthogonal to the fore-aft axis. The drive track assemblies are mounted opposite each other at the ends of the adjustable axle assembly. The first actuation system is capable of mechanically moving the adjustable axle assembly to thereby adjust the fore-aft position of the drive track assemblies relative to the frame. The second actuation system is capable of mechanically rotating the adjustable axle assembly to thereby adjust the pitch of the drive track assemblies relative to the frame.
In such a fifth embodiment 20E of the vehicle 20, the vehicle 20E may further include one or more electronic controllers onboard. In one practicable embodiment, such an electronic controller may be mounted to the body and electrically connected to the first actuation system. In this configuration, the electronic controller is capable of communicating electrical control signals to the first actuation system to thereby adjust the fore-aft position of the pair of drive track assemblies as necessary to actively help maintain the fore-aft balance and stability of the vehicle 20E. In the same or other embodiment, an electronic controller may be mounted to the body and electrically connected to the second actuation system. In this configuration, the electronic controller is capable of communicating electrical control signals to the second actuation system to thereby adjust the pitch of the pair of drive track assemblies as necessary to lift and actively help maintain each front ski off the ground.
In embodiments 20D and 20E of the vehicle 20, the combination of a moveable dual fore-aft axle system to balance the vehicle over its axle assembly and also a two pairs of wheels fore-aft axle format helps provide a balanced and stable vehicle base in conditions of poor traction and also facilitates aggressive zero-turn capability. Herein, it is to be understood that some practicable embodiments of the vehicle 20 may include an electronic rotational controller 296 for the adjustable dual axle assembly, as best shown in
In embodiments 20D and 20E of the vehicle 20, it is therefore an object of the present invention to provide an oscillating dual axle drive wheel system that is mounted in such a way so as to allow powered movement of the axle system forward and rearward relative to the vehicle.
It is further an object of the present invention to provide a pivoted system that carries a suspension for the oscillating dual axle drive wheel system, with suspension being wholly linked to both sides of the dual axle system or independent in operation to each side of the dual drive axle system. It is to be understood by those in the art that the drive axle suspension could also be dependent and utilize the adjustment controls as a component of the suspension.
It is further an object of the present invention that the oscillating dual axle moveable drive wheel system is in communication with one or more electronic controllers having various associated sensors that are capable of sensing change of slope (i.e., attitude sensors 120L and 120R) and vehicle loading (i.e., load sensors 106L, 106R, and 106B) such that the sensors, by way of communication through the controller, effectuate movement of the drive axle system to adjust the weight balance of the vehicle above its drive axle such that the vehicle maintains desired fore-aft stability on the free oscillating center of the dual axle system.
It is further an object of the present invention that the moveable oscillating dual axle drive system may be provided with powered control of the oscillation of the dual axle so as to effectuate greater load on one or the other of the dual drive wheel pairs, including the lifting of one of the wheel pairs off the ground, or of effectuating the tilting of the entire vehicle utilizing a combination of the controlled oscillation (i.e., rotation) and fore-aft adjustability of the axle system.
It is further an object of the present invention that the moveable dual axle drive system may utilize mounting so as to have an unsuspended assembly, individual independent “A” arm type suspensions mounted thereon, utilize a knee action swing arm suspension component integral with the pivotally mounted drive axle carrying the dual axle oscillation pivot, utilize an active independent linear motor type suspension, or other suspension method in conjunction with the moveable drive axle system.
It is to be understood that activation of the movable axle system may be effectuated by a variety of different methods or actuators such as, for example, a hydraulic cylinder, an electric actuator, a rotary actuator, a linear electric motor, mechanical linkage, and manual changes, as known by those skilled in the art. Furthermore, movement and/or motion of the movable axle may be accomplished by a variety of methods such as a pivoting system, a sliding system, a mechanical linkage system, and manual changes, as known by those skilled in the art.
It is further an object of this invention that activation of controlled oscillation or rotation of the dual axle system, independent or dependent, right or left side of the vehicle, may be effectuated by a variety of different methods or actuators such as, for example, rotary hydraulic control, an active electric stepper motor, a hydraulic cylinder, a linear electric motor, mechanical linkage, an electric actuator, as known by those skilled in the art.
It is further an object of the present invention that the moveable oscillating dual axle system and the traction and stability effect resulting from the appropriate movement of the oscillating dual drive axle relative to vehicle balance allows accounting for operation on steep slopes, sudden acceleration or braking, or for changes in vehicle loading and vehicle wheelbase configuration. By way of example,
In summary, therefore, the present invention of a moveable dual drive axle system utilizes a controller to move a drive axle system forward and rearward relative to the vehicle such that the relationship of the vehicle center of gravity relative to the centerline of the pivot of said dual drive axle system is changed. The moveable drive axle system may further be in communication with a controller having sensors capable of sensing change of slope and vehicle loading such that the sensors, in communication through the controller, effectuate movement of the dual drive axle system to adjust the weight balance of the vehicle above the dual drive axle such that the vehicle maintains desired fore-aft stability.
In general, the moveable dual drive axle system is a pivoted system carrying a free or powered oscillating pivot for the dual drive wheels. The pivot of the moveable drive axle system may be powered electronically, manually adjusted, and/or manually controlled. The pivoted system may carry independent suspensions for the individual drive wheels, dual axle beams having fixed wheel mountings, and/or a suspension for the drive axle system dependently.
In addition to the above, it is further a claim that the drive axle system suspension being dependent would utilize the adjustment controls as components of the suspension.
It is further a claim that features of the pivotally mounted dual drive axle system are applicable equally to dual tires mounting or track chassis mounting, and able to serve as the ground engaging component of the vehicle.
It is further a claim that the pivotally mounted drive axle system having independent suspension for each of its dual wheels may utilize an independent “A” arm type suspension mounted thereon to effectuate movement of the drive wheel thereon.
It is further a claim that the pivotally mounted drive axle system having independent suspension for each of its dual wheels may utilize a swing arm type suspension component integral with the assembly of the drive wheel thereon, or other suspension method in conjunction with oscillating beams of the dual drive wheel axle system.
It is further a claim that the pivotally mounted drive axle system having independent suspension for each of its dual wheels may utilize other suspension systems known by those knowledgeable in the art, such that suspension of the drive tires is effectuated within the pivotally mounted drive axle system.
It is further a claim that the electronic controller of the movable dual axle system may be a hydraulic cylinder, electric actuator, rotary actuator, electric linear motor, mechanical linkage, and manual method, as understood by those skilled in the art.
It is further a claim that control of the path and motion of the movable dual axle system may be accomplished by a variety o£ methods such as a pivoting system, a sliding system, a mechanical linkage system, and manual changes, as understood by those skilled in the art.
It is further a claim that the path of the moveable dual axle system may be configured to result in a significant upward or downward movement of the vehicle relative to the axle such that the vehicle body is possible to be held level fore-aft while going up or down slopes.
A controllable dual drive axle system of a vehicle whereby oscillating beams of the dual drive axle system are both free-oscillating and controllable oscillation. It is further a claim that the controllable oscillation is able to effectuate changes in tire traction, removal of a damaged tire from operation, removal from operation of the fore-positioned tires for reduction of drive and rolling effort of the vehicle, and ability to power oscillate the axle beams to effectuate lift of the front of the vehicle for the benefit of ease of zero-turn of the vehicle while balanced solely on the dual drive axle system. It is further a claim that the controller of the movable dual axle system's oscillating beams, either dependent or independent, may be a hydraulic cylinder(s), electric actuator(s), rotary actuator(s), electric linear motor(s), mechanical linkage(s), and manual method(s), as understood by those skilled in the art. With the vehicle having a controllable dual drive axle position system, the vehicle thereby has zero turn capability when utilizing the lift feature to lift the front end of the vehicle by power oscillation of the dual axle drive wheel beams, as understood by those skilled in the art, as a vehicle steered by independently varying the speed and direction of rotation of the drive wheels.
In general, a system for providing multiple axle drives utilizing controlled position of the multiple drive axles for maintaining vehicle balance and stability while maximizing traction capabilities of the vehicle is disclosed herein. An oscillating dual drive axle system and its associated suspension is moved so as to provide an improved fore-aft vehicle stability by achieving a movement of the center of gravity of the vehicle relative to the pivot of the oscillating dual drive axle. Control of the oscillation of the dual axle system further provides wheelbase stability options, reduction in drive wheels in use, and fore-aft tilting control of the vehicle balanced on a dual axle system. Advantages are realized with controlled movement o£ the axle system accounting for improved steering capabilities of a multiple axle drive vehicle, including zero-turn capabilities, controlled operation on slopes, sudden acceleration or braking, or for changes in vehicle loading and wheelbase and drive wheel configuration interests. Such a moveable oscillating dual axle system is seen to be applicable to vehicles of utility and/or mobility, such as turf care products, agricultural, construction, military, personal transportation, utility and delivery vehicles.
This concludes the detailed description of both the structures and operations of alternative embodiments of the vehicle 20 according to the present invention.
While the present invention has been described in what are presently considered to be its most practical and preferred embodiments and/or implementations, it is to be understood that the invention is not to be limited to the disclosed embodiments. On the contrary, the present invention is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims, which scope is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures as is permitted under the law.
The present invention claims priority from U.S. Provisional Application Ser. No. 60/683,002, originally entitled “Moveable Oscillating Dual-Drive Wheels on a Zero-Turn Vehicle,” which was filed on May 16, 2005.
| Number | Date | Country | |
|---|---|---|---|
| 60683002 | May 2005 | US |
