FIELD OF THE INVENTION
This invention relates to wheeled leaning vehicles used primarily for personal transportation. The preferred embodiment described below falls within the emerging class of very light electric vehicles, a sub-class of electric vehicles used primarily for human transportation.
BACKGROUND OF THE INVENTION
This invention relates to electrically propelled leaning vehicles. Within the set of prior art the following subsets are known:
Within the subset of electrically propelled vehicles are a variety of designs such as U.S. Pat. No. 5,918,692 which typically seek to minimize weight and maximize interior volume thereby resulting in centers of mass higher than their gas powered counterparts. The limitations of this sub-set of the prior art include significantly degraded vehicle handling, decreased corner entrance and exit speeds, greater passenger discomfort, and reduced traction in inclement environmental conditions such as rain or snow.
Within the subset of leaning vehicles a significant proportion envision complicated, inefficient drive systems which seek to transfer the output of a central power unit, such as a gasoline fueled engine, to a plurality of wheels. An examples of this includes U.S. Pat. No. 4,456,277. This prior art is significantly limited by including telescoping drive shafts, chain-tensioner systems, or other methods to deliver power to wheels that have a variable distance, camber, and lean relative to the power unit.
Within the subset of three-wheeled vehicles the prior art consists of designs which often have a leading or trailing single wheel opposite a pair of wheels. This subset is severely limited by the manner in which the two co-axial wheels are connected. Most limited are those which feature a solid axle interconnecting the two co-axial wheels, such as U.S. Pat. No. 3,776,353. These suffer from extremely poor cornering and handling. The prior art also includes a set of designs which interconnect the pair of co-axial wheels using mechanical or electro-mechanical linkages, such as U.S. Pat. No. 4,087,106. This sub-set typically lacks provision to return the vehicle, and thereby the rider, to a neutral position subsequent to cornering, turning, or other handling maneuvers.
The herein described invention overcomes the significant limitations of the prior art:
SUMMARY OF THE INVENTION
By combining one or a plurality of in-hub electrically powered motors with the novel leaning mechanism described herein, a vehicle capable of leaning into curves and handling in direct response to rider weight shifts is achieved. In one embodiment the powered wheel is located in front of the standing rider, with two turning, canting wheels placed behind the rider. The rider is able to use handlebar controlled steering during slow-speed maneuvering and is able to tilt the riding platform, by shifting pressure to one foot or the other, to add in a variable and instantaneous amount of rear-steering. In another embodiment one to four in-hub electrical motors are employed, up to one on each of four wheels, two afore and two behind the seated or standing rider. The novel leaning mechanism described is placed both afore and behind the rider and each interconnects the two associated, powered wheels. In this embodiment an all wheel drive, lean steering, electric vehicle is established.
In one aspect a lean steering vehicle includes a main platform and a front wheel assembly coupled to a forward end of the main platform. A torsion hanger assembly is coupled to the main platform, is rotatable around a first axis, and provides resistive force against rotation around the first axis from a neutral position. A first swing arm is rotatably coupled to the torsion hangar assembly. A first rear wheel is rotatably coupled to the first swing arm at a point distal to the point at which the first swing arm is coupled to the torsion hangar assembly. An electric motor is coupled to at least one of the front wheel assembly and the rear wheel to provide a driving force. Additionally a second rear wheel can be included and coupled to the vehicle in the same manner as the first rear wheel.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an external side view of a preferred embodiment of the presently disclosed vehicle.
FIG. 2 is a cross sectional side view of the vehicle
FIG. 3 is an external rear view showing the vehicle in a cornering configuration
FIG. 4 is a partial cross sectional top view of the leaning mechanism which interconnects a pair of wheels
FIG. 5 is a schematic showing vehicle geometries
FIG. 6 is an electrical block diagram of the vehicle power circuit
FIG. 7 is an alternative configuration of the presently described invention shown as a pair of leaning mechanisms
DETAILED DESCRIPTION OF THE DRAWINGS/DESCRIPTION OF A PREFERRED EMBODIMENT
The following detailed description is directed to certain specific embodiments of the invention. However, the invention can be embodied in a multitude of different systems and methods. In this description, reference is made to the drawings wherein like parts are designated with like numerals throughout.
As shown in FIG. 1 a preferred embodiment of the herein described vehicle includes a front wheel assembly 101 comprised of a tire 102 and hub 103 or other support structure which contains a motor concentric to the front axle 104. This axle 104 connects the handlebars 105 and steering column or columns 106 to the wheel assembly 101. In this embodiment the rider stands atop the main platform 107. In another envisioned embodiment the rider is seated on a structure rigidly mounted or suspended from either the main platform 107 or the rear platform 108. In the presently shown embodiment the rear platform 108 serves to protect the rider from the rear wheel assembly 120 while providing a mounting location for a seat, storage, display, engine to support hybrid-electric operation, or other accessories. Pivotally mounted and interconnecting the front wheel assembly 101 to the rear wheel assembly 120 is a supporting frame 110. In another envisioned embodiment a monocoque design supports the rider via the main platform 107 and interconnects the pivotally mounted front wheel assembly 101 and the rear wheel assembly 120. It is envisioned that any of a variety of commonly known suspensions systems, such as coil-over spring-damper systems can be combined with the rear wheel assembly 120, with the front wheel assembly 101, or both.
In this presently described embodiment the rear wheel assembly 120 is comprised of a pair of swing arms 121 which span the distance between the torsion hanger assembly 122 and the rear wheels 123. Each rear wheel 123 is mounted to a swing arm 121 so as to provide free rotation, in this embodiment through the use of sealed bearings. The swing arms 121 also directly support brake calipers 124 which transfer force onto rear brake rotors 125, which are concentrically mounted to the freely rotating rear wheels 123, in order to stop the rotation of the said rear wheels 123.
As shown in FIG. 2 the afore described vehicle is presented in cross section. Batteries 201 are housed within the frame 110 and connected electrically to the controller device 210 and thereby the front in-hub motor 103. In an illustrative embodiment the front in-hub electrical motor is of a power rating ranging from 250 Watts to 2500 Watts and the batteries are an assembly of cells totaling 12 to 96 Volts. Activation of this circuit occurs by manipulation of the handlebar 105 mounted throttle 202 and results in forward motion of the vehicle. The torsion hanger assembly 122 houses a torsion spring 230 and rotates freely about a vertical axis of rotation. The torsion hanger assembly 122 and torsion spring 230 are limited in other axes and planes of motion by a top plate 231 and a bottom torsion hanger base 232 which is rigidly mounted to the frame 110. Sealed top 233 and bottom 234 bearings allow free rotation about the axis of rotation while a pivot bolt 235 interconnects the top plate 231 and bottom torsion hanger base 232. In this manner, leaning of the main platform 107 results in the compression of the torsion spring 230 (or other spring force source such as an elastic polymer element) and a combined, proportional tilt and rotation of both rear wheels 123. A decrease in the amount of lean of the main platform 107, for example by the rider changing downward pressure on a point not located on the longitudinal axis of the main platform 107, results in the spring force (though the force can be provided by a source other than a spring) overcoming this pressure exerted on the main platform 107 and thereby causes the vehicle to return to its neutral, in this instance upright position. In one embodiment the torsion hangar assembly is as described in U.S. patent application Ser. No. 12/406,829, titled Lean Steering Truck With A Torsion Spring Assembly, filed Mar. 18, 2009, hereby incorporated by reference.
As shown in FIG. 3 the previously described vehicle is shown in a leaning configuration. The rider (not shown) is normal to the main platform 107 and nominally parallel to the steering column 106. The rear wheels 123 rotate, as a set, about the central, vertical, axis of rotation which is coaxial to the pivot bolt 235. A control arm 310 connects each swing arm 121 to the torsion hanger base 232. These control arms 310 limit the motion of the swing arms 121 and create a linear and inverse relationship between the lean of the main platform 107 and the rotation of the rear wheel assembly 120. In the preferred embodiment the control arms 310 are connected to the torsion hanger base 232 and to the swing arms 121 using a ball or Heim joints 311. When, as in envisioned herein, these control arms 310 are placed in parallel to, and directly below, the longitudinal axis of the swing arms 121 stresses on the assembly 120 are minimized. As the main platform 107 is leaned a reactionary ground force acts upon the inside rear wheel and thereby the inside swing arm 121 and inside control arm 310 such that the torsion spring is compressed. The restorative spring force counteracts this sequence of events causing the main platform 107 and thereby the rider to return to a neutral position.
As shown in FIG. 4 the leaning mechanism is shown in top view, partial cross section. The swing arms 121 are connected to the torsion hanger housing 410 by way of swing arm bolts 411. Sealed bearings 412 allow the free rotation of the swing arms 121 about an axis of rotation defined by the longitudinal axis of the swing arm bolts 411. Control arms 310 spherically rotationally join the swing arms 121 to the torsion hanger base 232. The torsion hanger housing 410 is allowed to rotate about an axis of rotation normal to the primary axis of the vehicle platform 110 and defined by the longitudinal axis of the pivot bolt 235. The torsion spring 230 is secured by way of spring guides 420 and spring stops 421, or alternatively an enclosing spring chamber, which are adjustable by way of a plurality of set screws 422. Manipulating the set screws 422 results in increased or decrease compression of the torsion spring 230. A change in compression has a direct and necessary impact on the ride dynamic and in particular the amount of force exerted by the torsion spring 230 in order to return the vehicle to an upright position. A reduction in spring force results in a more complaint vehicle that less forcefully returns to an upright position. Conversely an increase in spring force results in a vehicle that more forcefully returns to an upright, neutral position. The torsion spring 230 housed within the spring chamber 430 is compressed prior to assembly of the rear wheel assembly 120 so as to provide a riding situation in which the torsion spring 230 is continuously in compression. The swing arms 121 directly and rigidly house the brake calipers 124 thereby eliminating additional hardware or mechanical connections and reducing the overall weight of the swing arms 121. On the external surface of the torsion hanger housing 410 are two mechanical protrusions, in this embodiment threaded blots 430, serving to limit the range of free rotation about the pivot bolt 235 and thereby the extent to which the main platform 107 and the vehicle frame 110 is allowed to lean relative to the road surface.
In one embodiment the torsion spring 230 and spring chamber 430 form an interchangeable sub-assembly which, when changed to a torsion spring 230 of varying spring constants so vary the ride dynamics of the vehicle. In another embodiment the torsion spring 230 is of a progressively varying spring constant; for every degree the torsion spring 230 is compressed an incrementally varying force is exerted upon the assembly 120 thereby providing varying ride dynamics in relation to the lean angel of the main platform 107.
As shown in FIG. 5 the front wheel assembly 101 is connected to the steering column 106 by way of the front axle 104. This distance from the real location of the axle 104 to the closest point along the longitudinal axis of the steering column 106 is described by the offset 510. In a preferred embodiment this offset is between 0 and 6 inches. Where radius 501 of the front wheel assembly 101 normally intersects the ground plane 502 is the point 503. Another point 504 is located where the longitudinal axis of the steering column 106 intersects the ground plane 502. The distance between points 503 and 504 is the trail distance 520. In a preferred embodiment the trail distance 520 is between 0 and 3 inches. Where the rear wheel 123 radius 505 normally intersects the ground plane 502 is the point 506. The distance between point 503 and point 506 is the wheelbase 530. In a preferred embodiment the wheelbase is between 40 and 120 inches. The careful calculation of the aforementioned geometries results in a natural, balanced riding experience and is governed by Proportionality 1:
- Lean to Turn Ratio∝{Rider Weight, Vehicle Weight, Torsion Spring Constant, Swing Arm Lengths, Front Wheel Offset, Front Wheel Trail, Wheel Base, Front and Rear Wheel Radii}
And the Restorative force exerted upon the vehicle and rider is governed by Proportionality 2:
- Restorative Force∝{Normal Force, Length of Swing Arms, Wheel Radii, Inflated Tire Spring Constant, Torsion Spring Constant, Combined Rider and Vehicle Weight, and Wheel Base}
As shown in FIG. 6 electrical energy is stored in batteries 601. The batteries 601 are connected to the controller 602 by electric wires. Given input from the handlebar 105 mounted throttle 603, power is proportioned and transmitted to the in-hub electrical motor 604. The controller 602 also proportions and powers accessories including lights 605, and audible horn 606, and a display showing battery charge level 607. Actuation of either one of two brake levers 608 results in a cutoff signal being sent to the controller 602. In the case of deceleration with no input from the throttle kinetic energy is transformed into electrical energy by the motor 604 and transferred into the batteries 601 by way of the controller 602.
In an alternative embodiment the controller 602 includes a secondary all wheel drive controller 610 to regulate power distribution and monitor power distribution to each of Left Front Motor 611, Right Front Motor 612, Left Rear Motor 613, Right Rear Motor 614. In this manner an all wheel drive configuration is achieved together with a sensing system to monitor and counteract wheel slippage and respond directly to varying wheel speeds, as in cornering.
As shown in FIG. 7 a pair of rear wheel assemblies 120 can be used. As previously described, the rear wheel assembly 120 is place behind the standing or seated rider and attached rigidly to the frame 110. In this alternative configuration a second rear wheel assembly 120 is attached afore the rider and also rigidly attached to the frame. The result is a four wheel leaning vehicle. Power is provided as previously described to in-hub electric motors located at either the front 710, 711 wheels or the rear wheels 720, 721. Intelligent All Wheel Drive is also envisioned, also as previously described, wherein the in-hub electric motors are located on all four wheels 710, 711, 720, 721.
The above description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles described herein can be applied to other embodiments without departing from the spirit or scope of the invention. Thus, it is to be understood that the description and drawings presented herein represent exemplary embodiments of the invention and are therefore representative of the subject matter which is broadly contemplated by the present invention. It is further understood that the scope of the present invention fully encompasses other embodiments and that the scope of the present invention is accordingly limited by nothing other than the appended claims.
Patent Application
20110266079
