WO2014108275A2

WO2014108275A2 - Skateboard and skateboard truck with axle-mounted motor

Info

Publication number: WO2014108275A2
Application number: PCT/EP2013/076698
Authority: WO
Inventors: Richard J. Hodgson; Gary GUIRAGOSIAN; Kevin LEVI
Original assignee: Hodgson Richard J; Guiragosian Gary; Levi Kevin
Priority date: 2013-01-08
Filing date: 2013-12-16
Publication date: 2014-07-17
Also published as: WO2014108275A3

Abstract

A skateboard has a wheel and axle assembly and a truck assembly. Each of the wheels is coupled to a drive transfer plate, which is further coupled to a motor shaft of a motor. Therefore, each wheel is driven by its own motor. Each motor is supported within a hollow axle casing of a wheel axle of the skateboard. A controller attached to each electronic speed control of each motor controls the rotational force provided by each of the motors to each of the wheels coupled to the motors. Since each wheel is attached to an individual motor, each motor may be independently controlled and rotational force provided to each of the wheels may be different.

Description

SKATEBOARD AND SKATEBOARD TRUCK WITH AXLE-MOUNTED MOTOR

FIELD

The present subject matter relates to skateboards, and more particularly to skateboards with axle-mounted motors.

INTRODUCTION

Skateboards have been used for decades. Typically, skateboards are not powered for self propulsion and they are confined to use on generally smooth surfaces, such as asphalt or concrete. However, to increase the rider's excitement potential, skateboards have occasionally been modified to include a motor to power the skateboard, and skateboards have also been modified to be adapted for off-road use on non-smooth surfaces.

United States Patent No. 6,467,560 describes a transmission unit for a recreational vehicle that comprises a steering arrangement that is controlled by movement of the weight of the user, a driving assembly that includes a free-wheeling clutch, as well as a suspension assembly and a braking assembly. The vehicle also includes an engine (with a gearbox and clutch) and a user support platform, and is adapted for use both on- and off-road. The transmission unit is connected between the engine and at least one axle, through a drive train. The vehicle may include wheels with balloon tires as part of the adaptation for all terrain capability. A remote control may be remote from the vehicle and hand-operable.

United States Patent No. 6,751 ,560 describes a power transmission device having at least two one-way clutches which is used to transmit the driving force of the power generator to the right and left drive wheels. By this power transmission device, it is possible to transmit the driving force of the power generator to the right and left drive wheels almost half and half when the wheels' contact loads are the same. While if the drive wheels rotate at a different speed, hardly any driving force is transmitted to the side of the drive wheel which can rotate faster and the driving force is mainly transmitted to the wheel rotates slowly. Accordingly, it is possible to transmit the power without fail to the drive wheel which touches the ground even when the transportation device is curving or slipping, or when one of the wheels parts from the ground. United States Patent No. 7,789,180 describes an inflatable article having a single inflatable enclosure comprising a body portion and one or more rotary portions that can rotate relative to the body portion. The article may be a vehicle, wherein the rotary portions are wheel portions which support and are driveably rotatable relative to the body portion. The wheel portions may be connected to the body portion by hollow tubular axles which have outlets inside the wheel and body portions to provide fluid communication therebetween.

United States Patent Application publication No. 2005/0139406 describes a skateboard that has a platform supported on a tubular frame. The frame is engaged with a pair of wheel trucks, one with a at least one wheel, the other with a pair of wheels. An electrical motor, and a power source are mounted below the platform to the frame. The at least one wheel is positioned proximate a forward end of the platform, and the pair of wheels are positioned proximate a rearward end of the platform. The motor engages the at least one wheel and is able to be turned on and off by a remote switch accessible to a hand or foot of the rider. Front and rear receivers enable attachment of a wide range of accessories including a seat, handle bar and lights.

United States Patent No. 6,050,357 describes a powered skateboard including a foot support, multiple wheels mounted to the foot support, and a motor coupled to at least one of the wheels. The powered skateboard further includes an active control system having a sensor located on the skateboard and a controller. The controller receives electrical signals from the sensor and electrical signals from the motor, which indicate the state of the motor. In response to those signals and in accordance with a control mechanism, the controller sends electrical signals to the motor to control the operation of the motor.

United States Patent No. 5,975,229 describes a stand-up transportation device comprising shafts to which the front wheel and the rear wheel are assembled respectively, and a frame connecting these shafts. This transportation device also has drive equipment that can drive the wheels on the shafts. Therefore, the user can run on a plane, an ascending slope or a rough road standing on the frame of this automatic transportation device as when riding on a snowboard or the like, and changing the course by shifting their weight. As the transportation device is made of the shafts and the frame combined in a simple way, the user can readily enjoy riding on it at any time and anywhere. And the user can enjoy the drive feeling as they ride on a snowboard and the like without snow. Also, they can enjoy riding on it for a long distance or time.

United States Patent No. 7,044,485 describes the Elastomer Suspension System Skateboard Truck is proposed for use in all styles of skateboarding. This new design is unlike any conventional skateboard truck. The truck incorporates an elastomer suspension system, which is a modification of the type used in automotive vehicles and other mechanisms utilizing shock absorbing equipment. The elastomer shock absorbers oppose pressure from end to end, therefore diminishing or eliminating all forces associated with sudden or rapid motions. By downgrading or eradicating these extreme shock forces the skateboarder has more control, and is therefore more maneuverable.

United States Patent Application No. 2010/0327546 describes a vehicle includes a chassis, a suspension system, and a steering system operably coupled to the chassis and to the suspension. The chassis includes a mounting member that has a first elongated slot. The suspension system includes a beam that is pivotally coupled to the mounting member. The steering system includes a first axle, a second axle, a tie bar that extends between first and second tie bar ends, and a slider. The first and second axles are pivotally coupled with respect to the beam. The tie bar is operably coupled to the first and second axles and includes a second elongated slot that is configured to overlie the first elongated slot. The slider is positioned in the first and second elongated slots, and is configured to move in the first and second elongated slots to select a ratio of the tilting of the mounting member to the steering of the first and second axles.

SUMMARY

In accordance with one embodiment, there is provided a wheel and axle assembly comprising: a hollow axle casing defining a first open end; a first wheel having an axial opening for receiving the hollow axle casing, the wheel being rotatable about a first portion of the hollow axle casing; a first drive transfer plate engageably coupled to the first wheel; and a first motor assembly supported within hollow axle casing, and coupled to a first motor shaft projecting through the open end of the hollow axle casing to engage the drive transfer plate, the motor assembly for providing a rotational force to the motor shaft for causing rotation of the first drive transfer plate and the first wheel coupled thereto.

In accordance with another embodiment, there is provided a truck assembly comprising: an upper bracket having a plate portion for coupling the upper bracket to a skateboard deck, the plate portion defining a lengthwise direction and a plane, and at least one support member extending from a surface of the plate portion in a direction transverse to the plate portion plane; and a pivot bracket having a lower portion for securing a wheel axle and having at least one extending member extending from the lower portion, the extending member being pivotally attached to the first support member to define an axis of pivot.

In accordance with yet another embodiment, there is provided a skateboard comprising: a first wheel; a second wheel coaxial with the first wheel; a first motor for providing rotational force to the first wheel; a second motor for providing rotational force to the second wheel independently of the providing of force by the first motor to the first wheel; and a controller configured for: receiving user signals for controlling the first and second wheels; and controlling the providing of the rotational force to the first wheel by the first motor; and controlling the providing of the rotational force to second wheel by the second motor independently of the controlling of the providing of the rotational force to the first wheel by the first motor.

DRAWINGS

The drawings included herewith are for illustrating various examples of articles, methods, and apparatuses of the present specification and are not intended to limit the scope of what is taught in any way. These and other features of exemplary embodiments will become more apparent from the following description in which reference is made to the appended drawings wherein:

Figure 1 is a perspective view of an exemplary embodiment of a skateboard;

Figure 2 is a perspective view of an exemplary alternative embodiment of the skateboard;

Figure 3 is a perspective view of a top of an exemplary embodiment of the skateboard;

Figure 4 is a perspective view of an exemplary embodiment of a protection panel;

Figure 5 is an elevation view of a side of an exemplary embodiment of a skateboard;

Figure 6 is an exploded view of a portion of an exemplary embodiment of a wheel and axle assembly;

Figure 7 is an exploded view of a portion of an exemplary embodiment of the modified wheel and axle assembly;

Figure 8 is a section view taken along the longitudinal axis of a portion of the exemplary embodiment of the modified wheel and axle assembly;

Figure 9 is perspective view of an exemplary embodiment of a truck assembly;

Figure 10 is a side view of the exemplary embodiment of the truck assembly; Figure 1 1 is a perspective view of an exemplary embodiment of a truck assembly with a modified wheel and axle assembly;

Figure 12 is a perspective partial section view of an exemplary embodiment of the modified truck assembly;

Figure 13 is a side section view of the exemplary embodiment of the modified truck assembly;

Figure 14 is a front elevation view of a portion of the exemplary embodiment of the modified truck assembly;

Figure 15 is a front elevation view of a portion of the exemplary embodiment of the modified truck assembly;

Figure 16 is a front elevation view of a portion of the exemplary embodiment of the modified truck assembly;

Figure 17 is a side schematic diagram of operation of the exemplary embodiments of a skateboard.

DESCRIPTION OF VARIOUS EMBODIMENTS Referring to Figures 1 and 2, illustrated therein is a perspective view of an exemplary embodiment of a skateboard 2 with axle-mounted motor. The skateboard 2 comprises two front wheels 4 and 6 which are mounted to a front axle 8. The axle 8 is mounted to the bottom 10 of the skateboard deck 12 by a truck assembly 14. The front wheels 4, 6 may be made of a suitable material and are a suitable size to allow the skateboard 2 to be used in some instances for off-road purposes, such as riding over rough terrain.

The exemplary skateboard 2 further comprises rear wheels 16 and 18, which are mounted to a rear axle 20. The rear axle 20 is mounted to the bottom 10 of the skateboard deck 12 by a rear truck assembly 22. The rear wheels may also be made of a suitable material and are a suitable size to allow the skateboard 2 to be used for off-road purposes.

According to some exemplary embodiments, the skateboard 2 further comprises a controller 30. The controller may be mounted to the bottom 10 of the deck 12, as shown in Figure 1. The controller 30 may have a sensor to receive user control signals for controlling the operation of the skateboard 2. For example, the sensor of controller 30 may be a receiver for receiving radio frequency user control signals.

Alternatively or additionally, the sensor may be an infra-red sensor or other suitable rider position/distance measuring sensor for detecting the position of one or more body parts of the user riding the skateboard 2, wherein the detected position of one or more body parts provide the user control signals. For example, as shown in Figure 3, controller 30 having an infra-red sensor may be located on a top 11 of the deck 12. Infra-red sensor may be located at the front of the board, rear of the board, or any other location that allows for detection of the position of one or more body parts.

The controller 30 may be connected to one or more electronic speed controls (ESC) via one or more control lines. For example, the controller 30 in the exemplary embodiment shown in Figure 1 is connected to front right ESC 36 via control line 37, front left ESC 38 via control line 39, right rear ESC 40 via control line 41 , and left rear ESC 42 via control line 43. Each ESC is connected via electrical lines to an electric motor, which provides rotational force to the wheels of the skateboard. Alternatively, one ESC may be connected to multiple motors. All references to motors in the described embodiments shall mean electric DC motors with or without reduction gearbox(es) attached to the motors directly or via a drive shaft. In order to optimize energy efficiency, skateboard weight, axle diameter, ground clearance, or a combination thereof, some embodiments would have sensored brushless motors. Each ESC delivers current and modulates the current delivery for controlling the rotational force provided by the electric motor to which it is connected. For example, right front ESC 36 is connected to a first motor via electrical line 44a, left front ESC 38 is connected to a second motor via electrical line 44b, right rear ESC 40 is connected to a third motor via electrical line 45 and left rear ESC 42 is connected to a fourth motor via electrical line 46. The delivery of current by each ESC is controlled by the controller 30 based on received user control signals. Electrical power is provided by battery packs 50, 52, 54 and 58, each being connected to one of the ESCs. Alternatively, 2 or more ESCs can be connected to 1 or more battery packs.

As shown in Figures 2 and 3, according to exemplary embodiments where the controller 30 is mounted to the top 11 of the deck 12, control lines may project through an opening 34 in the deck 12 to connect the controller 30 with one or more ESCs.

Each wheel of the skateboard may be directly mounted to one electrical motor that is controlled by a connected ESC and battery. Therefore, for the four wheeled skateboard 2 shown in Figure 1 , four motors are provided, each being connected to one of the wheels. However, according to other embodiments, only some of the wheels may be connected to an electrical motor.

For example, in some embodiments two electrical motors are located on the rear axle with the right rear wheel 16 being connected to one of the two electrical motors and left rear wheel 18 being connected to the other of two electrical motors. Accordingly, the front wheels 4 and 6 may not be connected to any motors and are therefore left unpowered. Alternatively, two wheels on the same axle may be powered by a single electrical motor. For example, rear wheels 16 and 18 may be both connected to the same electrical motor.

According to exemplary embodiments wherein one or more of the wheels is directly connected to an electric motor via a motor shaft and each electric motor is connected to one ESC, the rotational force may be provided by the motor to the connected wheel independently of the providing of rotational force by any other motor to another wheel. For example, the rear wheels 16 and 18 of skateboard 2 may each be mounted to a separate electric motor. The first electric motor mounted to right rear wheel 16 provides rotational force to the right rear wheel 16. The second electric motor mounted to left rear wheel 18 provides rotational force to the left rear wheel 18 independently of the rotational force provided from the first electric motor to the right rear wheel 16. Thus, the first electric motor may provide more rotational force to the right rear wheel 16 than the rotational force provided by the second electric motor to the left rear wheel 18 to cause the right rear wheel 16 to rotate faster than the left rear wheel 18. Such a differential in rotation speed of the two wheels may be advantageous for causing tighter turning of the skateboard towards the right. This control of a tighter turning circle is relevant to address the limited turning circle of longer skateboards and also to improve the trade-off between significant truck steering (trucks materially away from 90 degrees to the board) and board stability (trucks closer to perpendicular to the board) thereby allowing for more stability with same or better turning circle. An extreme example of this use would be to apply positive rotational force to the two left side wheels whilst retardation force is applied to the two right side wheels such that the board would take a tight right turn. This can also be applied in a two wheel drive format providing the two motors are on opposing sides of the board. It will be appreciated that independent control of the rotational forces provided to each of the wheels allows for performing other maneuvers on the skateboard 2.

The controller 30 is configured for independently controlling the rotational force provided by each of the motors. As shown in Figures. 1 and 2, a control line 41 directly connects controller 30 to right rear ESC 40. A second control line 43, which is independent of control line 41 connects controller 30 to left rear ESC 42. The controller 30 is further configured to individually control the ESCs 36 and 38. For example, the controller 30 may send control signals to the right rear ESC 40 to control the rotational force provided to the right rear wheel 16, and send separate signals to the left rear ESC 42 to control the rotational force provided to the rear left wheel 18, independently of the controlling of the right rear ESC 40.

The control signals sent to the ESCs may indicate the levels of currents to be provided from the ESCs to the motors. For examples, the rotational force provided by a motor may be modulated according to the amplitude level of the current provided. By varying the sign of the current provided, forward or backward rotational force can be provided by the motor for rotating a wheel forwards or backwards. Furthermore, varying the sign of the current to provide forward or backward rotational force may also be used to retard the rotating of the wheel. For example, where a wheel is rotating in a forward direction, providing a backward, or anti-rotational, force, will have the effect of retarding, or braking, the rotation the wheel.

As described above, the controller 30 receives user control signals. The controller 30 then sends signals to the ESCs 40 and 42 for controlling the providing of rotational force by the electric motors based on the received user signals. User signals may be provided by a user operating a remote control. For example, the user may operate a directional pad or a joystick on the remote control. Alternatively, the remote control may be a pistol grip transmitter with a mounted steering wheel. The user may also send user control signals using any handheld device that is enabled to send wireless control signals, such as a cellular phone, smartphone, or tablet. For example, the handheld device and receiver may be Bluetooth enabled and linked. The handheld device may also be configured to run applications for receiving user input. For example, the application may detect the position of a finger on the touch-sensitive screen of the device to determine the direction, speed of travel, acceleration or retardation and the proportion of power to be delivered to different wheels of the skateboard 2. User control signals sent from the remote control are received by the controller 30. The controller 30 then determines first signals to be sent to the right rear ESC 40 for controlling the providing of power by the first electric motor to wheel 16 and second signals to be sent to the left rear ESC 42 for controlling the providing of power by the first electric motor to wheel 18 such that the differential in rotational speed of the wheels 16 and 18 results in a turning action corresponding to initial operation of the joystick of the remote control by the user.

According to some exemplary embodiments, the right front wheel 4 may be mounted to a third motor supported within axle 8 and the left front wheel 6 may be mounted to a fourth motor supported within axle 8. In such case, each motor of the skateboard 2 may provide rotational force to the wheel mounted to it independently of the rotational forces provided by any of the other three electric motors of the skateboard 2. For example, it may be possible to provide more rotational force by third motor to only the front right wheel 4 independently of the rotational force provided by the first, third and fourth motors.

For example controller 30 may be further connected to right front ESC 36 through control line 37 and left front ESC 38 through control line 39. The controller 30 can independently control the providing of rotational force to the front wheels 4 and 6 using control signals sent through control line 37 and 39. The control signals are sent based on user control signals received at controller 30.

As will be appreciated, independent control of the four wheels provides the possibility of multiple maneuvers when riding the skateboard 2. For example, it may be possible to have both right front wheel 4 and right rear wheel 16 rotating faster than both left rear wheel 6 and left rear wheel 18 to achieve a sharp left turning maneuver. For example, it may also be possible to control both rear wheels 6 and 18 to rotate faster than both front wheels 4 and 6 to achieve a loss of traction of the rear wheels to create oversteer. The oversteer effect may be similar to the movement used in snowboarding. According to some exemplary embodiments, a sensor may be provided on each of the wheels to detect a rotational speed of each of the wheels. The sensor may also, or alternatively, detect a rotational speed of the motors. Alternatively, the electric motors may each have equipped a sensor to detect the rotational speed of the motor. The ESCs 36, 38, 40 and 42 may be further configured to detect the rotational speed of one or more of the wheels or one or more of the motors sensed by the sensor of each wheel or motor. For example, a quick drop in the rotational speed of a wheel or of a motor when retarding the motor, beyond certain deceleration parameters, may indicate that the wheel is skidding. Accordingly the controller is configured to modulate the current being fed to that motor in order to stop the wheel from skidding. It will be appreciated that controlling the motor and wheel in this manner is equivalent to an automatic braking system and conversely, when accelerating, traction control.

Referring now to Figure 4, illustrated therein is a perspective view of an exemplary embodiment of the protection panel 60. To protect electrical components and electronic components from dirt, water, and debris projected towards the bottom of the skateboard 2 when the skateboard 2 is being ridden, the protection panel 60 may be provided to cover the electrical components. For example the protection panel may be fixed to the bottom surface 0 of the skateboard deck 12.

The protection panel 60 may be fabricated from a light-weight material that is resistant to dirt and water and that is sufficiently rigid so as to protect the components from the impact as obstacles are negotiated or loose surface material is thrown up by the tyres. The protection panel 60 defines a hollow interior for accommodating electrical components of the skateboard 2 such as the ESCs and the battery packs.

The protection panel 60 may comprise a middle portion 62. The location of the middle portion 62 when protection panel 60 is mounted to the bottom surface 10 of the skateboard deck 12 may correspond to the positioning of the battery packs on the bottom surface 10. The middle portion 62 can fit closely to the battery packs 50,52,54,58.

The protection panel 60 further comprises first raised portion 64 and second raised portion 66. The location of the first and second raised portions 64, 66 when the protection panel 60 is mounted to the bottom surface 10 of the skateboard deck 12 corresponds to the positioning of the ESCs 36, 38, 40 and 42 on the bottom surface 10. The raised portions 64, 66 each provide an additional air space within the hollow interior over and around the ESCs to aid in the cooling of the ESCs. Similarly the middle portion 62 may provide an air space over and around the battery packs 50, 52, 54 and 58 to aid cooling of the batteries. Alternatively, or additionally the protection panel 60 may be made of a thermal conductive material such as aluminum which if installed in contact with the ESCs and batteries may act as a heat sink for these items. The raised portions 64, 66 may further define cooling vents 68 for allowing flow of air from the surrounding atmosphere in and out of the additional air space provided by the raised portions 64, 66 to further aid in the cooling of the ESCs.

The protection panel 60 may further comprise a flange 70 surrounding a perimeter of the protection panel 60. The protection panel 60 may be mounted to the bottom surface 10 through the flange 70. The protection panel 60 may further comprise one or more quick release fixings for attaching the protection panel 60 to the bottom surface 10 of the skateboard deck 12 which permit quick release.

Referring now to Figure 5, illustrated therein is an elevation view of an exemplary embodiment of the skateboard 2 with the protection panel 60 mounted to the deck 12. It will be appreciated that the protection panel 60 shields the components of the skateboard 2 while providing a maximum ramp over along its length defined by the perforated line 72, thus reducing the risk of the skateboard being high centered when riding over obstacles. Referring now to Figure 6, illustrated therein is an exploded view of an exemplary embodiment of a wheel and axle assembly 100 of the skateboard 2. For the purposes of providing an example, the wheel and axle assembly 100 will be herein described with reference to front right wheel 4 mounted to the front axle 8, however it will be appreciated that the wheel and axle assembly 100 may be applied to any of the wheels and axles of exemplary embodiments of the skateboard 2.

Shown in Figure 6 is an end portion of the axle 8. The wheel and axle assembly 100 comprises a hollow axle casing 102 defining a longitudinal axis 101. The axle casing 102 has a body portion 104 defining a first cavity portion 106 and a first outer portion 108 extending longitudinally from an end of the body portion 104 and defining a second hollow interior portion. The diameter of the first outer portion108 is smaller than the diameter of the body portion 104. The first cavity portion 106 and the hollow interior portion are in communication with each other. An outer end of the first outer portion 108 further defines an end opening 110.

A first electric motor assembly 120 is placed within the first cavity portion 106 and supported within the body portion 104 of the hollow axle casing 102. A motor shaft 122 connected to the first electric motor assembly 120 extends axially from the first electric motor assembly 120 through the second cavity portion and projects through the end opening 110 of the first outer portion 108. Rotational force provided by the electric motor assembly 120 causes rotation of the motor shaft 122. When an object is attached to the motor shaft 122, the rotational force provided by the electric motor assembly 120 is transferred to the object by the motor shaft 122.

The first outer portion 108 projects through a center opening 130 of a hub 132 of the wheel 4 from a first side of the wheel 4. An end 124 of the first outer portion 108 engages a wheel lock nut 134 on the outside of the hub 132 of wheel 4. For example, the end 124 may comprise outer threads to threadedly engage the wheel lock nut 134 that has inner threads for receiving the end 124. The wheel lock nut 134 fixes the hub 132 of the wheel 4 to the axle 8. Bearings 140 and 142 may be further provided on either side of the hub 132 to facilitate rotation of the wheel 4 about the first outer portion 108 of the axle 8. For example, the hub 132 may comprise a circumferential recess about the opening 130 on a first side of the hub 132 for accommodating the bearing 140 and a circumferential recess on the second side for accommodating bearing 142. A spacer 144 may be further provided intermediate the bearings 140 and 142 to ensure that the bearings 140,142 are appropriately spaced apart along the longitudinal axis 101. Where bearings 140, 142 and/or spacer 144 are used, the first outer portion 108 also projects through openings in each of the bearings 140, 142 and spacer 144 to engage the wheel lock nut 134.

When the first outer portion 108 projects through the hub 132, the end of the motor shaft 122 projecting through the end opening 110 of the first outer portion 108 further projects through an opening 136 of the wheel lock nut 134 and engages a drive transfer plate 150. For example, the end of motor shaft 122 may have a splined end to engage the drive transfer plate 150. The splined end of the motor shaft may be a male spline having a particular cross-sectional shape, such as a square end, a hexagonal end, or a plurality of circumferentially arranged ridges, which mates with a female spline 152 having a corresponding cross-sectional shape at the center of the drive transfer plate 150 to rotationally engage the drive transfer plate 150. In an alternate embodiment, the drive transfer plate may be integral to a drive axle that is partially or totally within the rotating wheel hub so the drive transfer plate is also located within the wheel hub. The drive axle is attached to the end of the motor shaft.

Alternatively, one or more suitable connectors or shaft couplers or shaft to plate couplers may be used to connect the motor shaft 122 to the drive transfer plate 150. Such connectors may allow some play in the mating of motor shaft 122 to the drive transfer plate 150, which may be required for allowing alignment and position tolerances between the motor / gearbox shaft and the drive transfer plate. For example, the connectors may be rigid shaft couplings, flexible shaft couplings such as Ruland™, flexible clamp couplings, and spider couplings such as spider part numbers: MJC25-6-A and JD16-25-92-Y from Ruland Manufacturing.

The drive transfer plate 150 is engageably coupled to the wheel. For example, bolting elements 160 may fixedly mount the drive transfer plate 150 to an opposite surface of the hub 132 of the wheel 4. In this way, rotational force from the electric motor 120 is transferred by the motor shaft 122 to the drive transfer plate 150 such that the drive transfer plate 150 rotates, and thereby causes the wheel 4 to rotate about the longitudinal axis 101.

According to some exemplary embodiments, the drive transfer plate 150 may be moved away from engagement with the motor shaft 122 to allow for the wheels to freewheel, with similar impact of manual freewheeling hubs on four wheel drive vehicles. For example, a lever may be provided for an operator to selectively manually engage or disengage the drive transfer plate 150 from the motor shaft 122.

The electric motor assembly 120 comprises an electric motor. The electric motor may be selected to be a sensored brushless DC motor. A sensored brushless DC motor allows for better control of the torque being outputted through the motor shaft spline to the wheels. Moreover, DC motors are capable of braking the wheel through the driveshaft, which eliminates the need for a separate set of brakes on the wheel. In some embodiments, such a sensored brushless DC motor may comprise rare earth magnets to provide higher efficiency and power output and also reduce energy loss through unwanted heat.

It will be appreciated that placement of the electric motor assembly 120 inside the axle casing 102 of the wheel axle 8 wherein the motor is directly connected to the wheel 4 through the motor shaft 122 or connectors eliminates the need for more complicated means of transferring power from the electric motor to the wheels, such as chain drives or drive shafts extending the length of the skateboard. Moreover, axle casing 102 shields the motor assembly 120 and motor shaft 122 from impact and dirt and debris being thrown up during off-road use. It will be further appreciated the overall axle may be made lighter as no separate motor mounting plate or structure is required. Placing the motor assembly 120 within the axle casing 102 also allows in some cases for the axle to act as a heat sink for the electric motor being support within it. It will also be appreciated that fewer moving parts and fewer overall parts are required according to the embodiments described herein in comparison with other known power transfer means. It will also be appreciated that with smaller diameter motors, low profile batteries and ESCs the appearance of a powered skateboard will closely resemble a regular unpowered skateboard. Furthermore if the drive transfer plate 150 is disengaged from the motor shaft 150 and the motors to allow the wheels to freewheel, the powered skateboard would also have the functionality of a regular unpowered skateboard. This may have advantages to the rider who is traveling from an area where powered skateboard use is accepted to an area where it is not and vice-versa. Furthermore other power transfer means such as chain drives, belt drives and drive shafts, often have various parts of the power transfer means being left exposed, which render such means more susceptible to wear and tear, if alternatively these parts are protected, additional parts and weight are integral.

In some embodiments, the electric motor assembly 120 may include a clutch that connects the electric motor to the motor shaft 122. The clutch can selectively engage the electric motor with the motor shaft 122 to select when rotational force is transferred to the motor shaft 122 and when the motor shaft 122 and wheel 4 can rotate freely from the electric motor.

In some embodiments, the electrical motor assembly 120 may further include a gear box for connecting the motor to the wheel 4. The gearbox may be used to modulate the amount of power and torque delivered to the wheel from the motor. A suitable gearbox is selected depending on various factors such as the specification of the motor of the electrical motor assembly 120 and the total circumference of the wheel 4. As it will be appreciated, Figure 6 illustrates only the portion of the axle 8 assembled with the wheel 4. An opposite end of the axle 8 assembled to wheel 6 mirrors the wheel and axle assembly 100, and comprises a second outer portion extending from the body portion in a direction opposite the first outer portion 108 and defining a third cavity portion and a second end opening. A second electric motor is placed within the first cavity portion 06 of the body portion 104 and has a second motor shaft connected to it which extends axially through the third hollow interior portion and projects through the second opening. The second outer portion extends through a center opening of a hub of the front left wheel 6 such that the wheel 6 rotates about the second outer portion. An end of the second motor shaft has a male spline to mate with a female spline at the center of a second drive transfer plate that is bolted to the hub of the wheel 6 such that rotational force provided by the second motor is transferred to the wheel 6 through the second motor shaft spline. Alternatively, a suitable connector or flexible or rigid shaft coupling or shaft to drive transfer plate coupling may be used to connect the second motor to the second drive transfer plate.

Referring now to Figures 7 and 8 together, illustrated therein an exemplary alternative embodiment of the wheel and axle assembly 100 of the skateboard 2, denoted therein as modified wheel and axle assembly 170. It will be understood that modified wheel and axle assembly 170 is in many aspects similar to wheel and axle assembly 100. Where additional details have not been provided, it will be further understood that the description for wheel and axle assembly 100 is also applicable for implementation of the modified wheel and axle assembly 170.

According to the exemplary alternative embodiment, the hollow axle casing 102 extends to end of the casing to define the end opening 110. Notably, the hollow axle casing 102 defines a single cavity portion 106 and an end opening 110. The single cavity portion 106 may have substantially the same diameter along its entire length. The hollow axle casing 102 may have at least two distinct portions having varying outer diameters. The electric motor assembly 120 is placed within the cavity portion 106. For example, as shown in Figure 8, the first electric motor assembly 120 may be placed proximate the end opening 1 0 of the hollow axle casing 102. Accordingly, the motor shaft 122 may be made shorter and project through the end opening 110 of the hollow casing 102.

A portion of the hollow axle casing 102 projects through the center opening 130 of the hub 132 of the wheel 4 from the first side of the wheel 4. The end 124 of the hollow axle casing 102 engages wheel lock nut 134 on an opposite end of the wheel 4. For example, the end 124 may have outer threads to threadedly engage the wheel lock nut 134 that has inner threads for receiving the end 124.

As shown in Figure 8, a portion of the hollow axle casing 102 is now received within the opening 130 of the hub 132. For example, the portion of the hollow axle casing 102 having the smaller diameter may be received within the opening 130 of the hub. Moreover, part of the electric motor assembly 120 is now also located within the center opening 130.

It will be appreciated that according to the alternative embodiment shown in Figures 7 and 8, the electric motor assembly 120 may be placed closer to the wheel 4 and in some cases even co-planar with the wheel. This may provide the advantage of allowing the motor shaft 122 to be shorter and also to limit the overall wheel track (width from outside of the left wheels to the outside of the right wheels). In some cases, this placement of the electric motor assembly 120 may also aid in the weight distribution of components of the skateboard. Furthermore, the volume of the cavity portion 106 defined by the hollow axle casing 102 is greater, which allows for a greater variety of configurations of the electric motor assembly 120, including configurations having one or more gearboxes, to be accommodated within the cavity portion 106.

Referring now to Figure 9 and Figure 10 together, therein illustrated is a perspective view and a side view respectively of a truck assembly of exemplary embodiments of the skateboard 2. For the purposes of providing an example, the front truck assembly 14 will be herein described; however, it will be appreciated that the exemplary truck assembly may also be applied to the rear truck assembly 22.

The truck assembly 14 comprises an upper bracket 201 that comprises a plate portion 202 having an upper surface 204 and a lower surface 206. The plate portion 202 may be substantially planar to define a plate portion plane but may also comprise a central recessed channel 208 for accommodating passage of electrical wiring. Plate portion 202 further comprises a plurality of throughholes 210 for receiving bolting members for bolting the plate portion 202 to the skateboard deck 12 with the upper surface 206 of the plate portion 202 lying against the bottom 10 of the skateboard deck 12. The plate portion 202 may further have a length, which is normal to the longitudinal axis of the wheel axle received in the truck assembly. The plate portion length defines a lengthwise direction, as denoted by arrow 211.

A first support member 212 extends from the lower surface 206 in a direction transverse the plane defined by the plate portion 202 and the skateboard deck 12. A second support member 214 may also extend from the lower surface 206 in a direction transverse the plane defined by the plate portion 202. The first support member 212 and second support member 214 may be spaced apart in the lengthwise direction defined by the plate portion 202. According to some embodiments, the first support member 212 and second support member 214 may be parallel. The first support member 212 may include a throughhole for pivotal attachment to a pivot bracket 220. Similarly, the second support member 214 may also include a throughhole for pivotal attachment to a pivot bracket 220. Preferably, the first and second support members 212, 214 and the plate portion 202 of the upper bracket 201 are integrally formed in one piece. However, in some embodiments, first and second support members 212, and 214 may be welded to plate portion 202 of the upper bracket 201. The truck assembly 14 further comprises a pivot bracket 220 for supporting a front axle 8. The pivot bracket 220 comprises a lower portion 222, which may have semi-cylindrical shape for supporting a wheel axle, as shown in Figure 6. The diameter of the lower portion 222 may correspond to the outer diameter of the hollow axle casing 102 of the axle 8 to firmly secure the wheel axle within the lower portion 222.

A first extending member 223 extends upwardly from a first rim of the lower portion 222. A second extending member 224 may also extend upwardly from a second rim of the lower portion 222. The first extending member 223 pivotally attaches to the first support member 212 of the pivot bracket 220. The second extending member 223 may be pivotally attached to the second support member 214. Attachment of the first extending member 223 and of the second extending member 224 to the upper bracket 201 enables the pivot bracket 220 to pivot with respect to the upper bracket 201 about a pivot axis 227 defined by the location of attachments of the first and second support members 212, 214 with the first and second extending members 223, 224. Preferably, the lower portion 222 and upward extending members 223, 224 are integrally formed in one piece. However, in some embodiments, the first and second extending members 223, 224 may be welded to lower portion 222 of the pivot bracket 220.

For example, an end region of the first extending member 223 comprises a throughhole and end region of the second extending member 224 also comprises a throughhole. The throughhole of the first support member 212 of the upper bracket is aligned with the throughhole of the first extending member 223, the two members being pivotally attached by a bolt member extending through both throughholes. Similarly, the throughhole of the second support member 212 of the upper bracket is aligned with the throughhole of the second extending member 224, the two members being pivotally attached by a bolt member extending through both throughholes.

A first resilient member 240 is coupled at a first end to the lower surface of the plate portion

202 and at a second end to the wheel axle 8 supported by the lower portion 222 of the pivot bracket 220. A second resilient member 242 is coupled at a first end to the lower surface of the plate portion 202 and at a second end to the wheel axle 8 supported by the lower portion 222 of the pivot bracket 220.

The first resilient member 240 and second resilient member 242 bias the wheel axle 8 to a neutral position. In the neutral position the wheel axle 8 is substantially parallel to the plane defined by the plate portion 202.

The first resilient member 240 and second resilient member 242 each exert a counterforce on the wheel axle 8 in response to the force exerted on the wheel axle 8 in the direction of the plate portion, for example as a result of the rider leaning on one side of the board.

The first resilient member 240 may be attached at the first end to be spaced apart on a first side of the lengthwise center of the plate portion 202 away from the second resilient member 242 which is attached at its first end on a second side of the lengthwise center of the plate portion 202.

As shown in Figure 9, the first resilient member 240 may be attached at a second end towards an outer portion of the wheel axle 8 such that the first resilient member 240 leans obliquely towards the front right first wheel 4 of the skateboard 2. Similarly, the second resilient member 242 may be attached at its second end towards an opposite outer portion of the wheel axle 8 such that the second resilient member 242 leans obliquely towards the front left wheel 6 of the skateboard 2. In an alternative embodiment the first and second resilient member may be connected to the axel within the central open section 280.

The first resilient member 240 and second resilient member 242 may be any type of resilient member that have an appropriate coefficient of elasticity for exerting an appropriate counterforce in response to the force to be exerted on the wheel axle. For example, the resilient members 240, 242 may be chosen according to the weight of the rider and/or the type of terrain to be traversed. For example, the first resilient member 240 and the second resilient member 242 may be coil springs.

According to some exemplary embodiments, the first support member 212 and the second support member 214 of the upper bracket 201 may partially extend in the lengthwise direction of plate portion 202. Accordingly, as shown, for example, in Figure 10, the first support member 212 and second support member 214 are slightly inclined in the lengthwise direction and therefore the pivot axis 227 defined by the attachment of the support members 212 and 214 with extending members 223 and 224 is at an angle 250 with the plane defined by the plate portion 202.

Alternatively, the truck assembly 200 may be mounted perpendicular to the board, such that leaning on the board has no impact on the steering. For example, the first support member 212 and second support member 214 is perpendicular to the board and does not have an incline in the lengthwise direction of plate portion 202. Accordingly, the axis of pivot is parallel to the plane defined by the plate portion 202. This manner of mounting has the effect that the axle behaves in a similar way to a live rear axle in a four wheel drive vehicle. Used in conjunction with the electronic rider controlled steering, rough terrain would not impact upon the steering of the board, thereby permitting greater board control. In traditional angled embodiment, for example a left wheel falling into a depression would cause the board to turn right, thereby destabilizing the rider, who may for example be leaning to the left in order to turn left. Therefore, the greater the angle of the trucks away from the perpendicular to the board, the greater the effect of undulations in the ground surface is exaggerated. Hence, further importance is attached to the ability to adjust the steering electronically.

For example, the first support member 212 and the second support member 214 may extend towards one of the ends of the skateboard deck 12. For example, as shown in Figure 5, the first and second support members 212 and 214 of the front truck assembly 14 are inclined towards the front end 260 of the skateboard deck 12 and the first and second support members 212' and 214' are inclined towards the back end 270 of the skateboard deck 12.

Referring back to Figure 9, the axle casing 102 of wheel axle 8 defines one or more axle openings 280, which provide access from the outside to the first cavity portion 106. The axle openings 280 may be a cutaway of the axle casing along the longitudinal axis of the axle. The axle openings 280 are useful for accessing the electric motor assembly 120 supported within the first cavity portion 106, for example for maintenance or replacement of the electric motor assembly 120 or parts attached to it. Additionally, electrical wiring connected to the electric motor assembly 120 may be passed through the axle openings 280. In embodiments with lower efficiency motors or with efficient motors with high current usage, the drive transfer plate 150 may have apertures which allow airflow in either direction through the end opening 110 of the axle housing 102, through the gearbox and motor and through the axle openings 280 to provide heat loss. This may also be augmented by the use of a fan housed within the axle housing 102 either separate from the motors or attached to the motors. In some embodiments where motor heat dissipation is required, the airflow would be drawn in through the axle openings 280 and fed out through the end opening 110 and through apertures in the drive transfer plate 150.

The axle openings 280 may further be useful for facilitating mounting of the axle 8 to the truck assembly of the skateboard. For example, resilient members 240 and 242 may extend through the axle openings 280 to be attached to an interior wall of the hollow axle housing 102.

Referring now to Figure 11 , therein illustrated is an exemplary embodiment of the truck assembly 14 having the modified wheel and axle assembly 170 supported therein. Referring now to Figures 12, 13, 14, 15 and 16, therein illustrated is an alternative embodiment of the truck assembly 14, denoted as modified truck assembly 288. It will be understood that modified truck assembly 288 is in many aspects similar to truck assembly 14. Where additional details have not been provided, it will be further understood that the description for truck assembly 14 is also applicable for implementation of modified truck assembly 288.

According to exemplary embodiments of the modified truck assembly 288, a rigid support member 290 extends from the lower surface 206 in a direction transverse the plane defined by the plate portion 202 and the skateboard deck 12. In particular, the rigid support member 290 defines an elongated guide slot 292.

The first extending member 223 of the pivot bracket 220 may attach to the rigid support member 290 at the guide slot 292. Similarly, second extending member 224 of the pivot bracket 220 may attach to the rigid support member 290 at the guide slot 292. For example, a bolt member 294 may project through a throughhole of the first extending member 223, the guide slot 292, and a throughhole of the second extending member 224 in order to attach both the first extending member 223 and the second extending member 224 to the rigid support member 290. Bolt member 294 may slide along the length of the guide slot 292 between at least a first position and a second position. Accordingly, the pivot bracket 220 and wheel axle 8 being supported by the pivot bracket 220 may also slide between at least a first position and second position.

According to some exemplary embodiments of the modified truck assembly 288, the first extending member 223 of the pivot bracket 220 may define a first elongated guide slot. The second extending member 224 of the pivot bracket 220 may define a second elongated guide slot parallel and opposite to the first guide slot. For example, the bolt member projects through the first guide slot, the second guide slot and a throughhole of the rigid support member 290 in order to attach both the first and second extending members 223 and 224 to the rigid support members. The bolt member may slide along the length defined by the first and second guide slots between at least a first and second position. Accordingly, the upper bracket 201 may also slide between at least a first position and second position relative to the pivot bracket 220 and the wheel axle 8.

For example, Figure 14 shows the pivot bracket 220 and wheel axle 8 in a neutral position wherein the bolt member 294 is disposed against a lower end of the guide slot 292.

In Figure 15, as a force is exerted on the wheels of the skateboard and therefore on the axle 8, for example, as both wheels 4 and 6 hit a bump in the terrain, the bolt member 294 is slid to a second position where the bolt member 294 is disposed against an upper end of the guide slot 292. The resilient members 240 and 242 then apply a counterforce to bias the pivot bracket 220 and wheel axle 8 to the neutral position.

In Figure 16, as an uneven force is exerted on one of the wheels in comparison to the other wheel of the same wheel axle 8, for example, as only one of the wheels 4 and 6 hits a bump in the terrain, the bolt member 294 is slid to be disposed against an upper end of the guide slot 292 and the pivot bracket 220 pivots about the upper bracket 201 such that the wheel axle 8 forms an angle with the skateboard deck 12. Resilient member 242 then applies a stronger counter force than resilient member 240 in order to return the pivot bracket 220 to the neutral position.

Referring now to Figure 17, therein illustrated is an exemplary embodiment of a user operating the skateboard described herein according to various embodiments. Controller 30 having a sensor, such as an infra-red sensor or other suitable rider position/distance measuring sensor, is mounted to a top side of the skateboard deck 12. The sensor may detect the position of one or more body parts of the user. For example, the sensor may detect the position of the user's head. For example, when sensor of the controller 30 detects that the user is in an upright position 300, the controller 30 may send control signals to the ESCs of the skateboard such that the travel of the skateboard is maintained at a constant speed. When the sensor detects that the user is in a forward-leaning position 302, the controller 30 may send control signals to the ESCs to supply increased rotational force to the wheels such that the speed of travel is increased. When the sensor detects that the user is in a backward-leaning position 304, the controller may send control signals to the ESCs to supply an anti-rotational force to retard the wheels and to decrease the speed of travel of the skateboard. This interpretation of signals ensures that the rider's attitude to the board is consistent with the force then applied such that board control is maintained. For example the rider must be leaning forward when strong accelerative forces are applied and similarly must be leaning towards the back of the board when braking forces are applied. This principle for controlling the board may be applied irrespective of whether the rider is in a forward facing stance as illustrated in Figure 17, or in a more traditional sideways facing stance (regular - left foot forward or goofy - right foot forward).

Embodiments described herein may be applied to skateboards used for recreational purposes, transportation purposes, or military purposes.

While the above description provides examples of the embodiments, it will be appreciated that some features and/or functions of the described embodiments are susceptible to modification without departing from the spirit and principles of operation of the described embodiments. Accordingly, what has been described above has been intended to be illustrative and non-limiting and it will be understood by persons skilled in the art that other variants and modifications may be made without departing from the scope of the invention as defined in the claims appended hereto.

Claims

CLAIMS:

1 , A wheel and axle assembly comprising:

a hollow axle casing defining a first open end;

a first wheel having an axial opening for receiving the hollow axle casing, the wheel being rotatable about a first portion of the hollow axle casing;

a first drive transfer plate engageably coupled to the first wheel; and a first motor assembly supported within hollow axle casing, and coupled to a first motor shaft projecting through the open end of the hollow axle casing to engage the drive transfer plate, the motor assembly for providing a rotational force to the motor shaft for causing rotation of the first drive transfer plate and the first wheel coupled thereto.

2. The assembly of claim 1 , wherein the first open end of the hollow axle casing threadedly engages a wheel lock nut for securing the first wheel about the hollow axle casing.

3. The assembly of claim 1 , wherein the motor assembly is further adapted to provide an anti-rotational force for retarding rotation of the first wheel.

4. The assembly of claim 1 , wherein the first drive transfer plate is selectively disengageable from the first motor shaft to allow the first wheel to freewheel.

5. The assembly of claim 1 , wherein the first motor shaft engages the first drive transfer plate via a mating of a female spline of the first drive transfer plate with a male splined end of the first motor shaft.

6. The assembly of claim 1 , wherein a connector engages the first motor shaft to the first drive transfer plate.

7. The assembly of claim 6, wherein the connector is selected from rigid shaft couplings, flexible shaft couplings, flexible clamp coupling, or spider coupling.

8. The assembly of claim 1 , wherein the motor assembly comprises a clutch for selectively providing rotational force to the motor shaft.

9. The wheel axle of claim 1 , wherein the motor assembly comprises a gearbox for adjusting the rotational force to the motor shaft.

10. The assembly of claim 1 , wherein the first motor is a sensored brushless motor.

11. The assembly of claim 10, wherein the first and second motors are both sensored brushless motors.

12. The assembly of claim 1 , wherein hollow axle casing defines one or more openings for receiving one or more control lines for controlling the providing of rotational force from the first motor.

13. The assembly of claim 1 , wherein the wheel and axle assembly further comprises a fan housed within the hollow axle casing for providing airflow through the axle casing.

14. The assembly of claim 1 , wherein the hollow axle casing is supported by a skateboard truck assembly and is further attached to a least one resilient member, the hollow axle casing being moveable about the truck assembly when attached.

15. The assembly of claim 1 , wherein the hollow axle casing comprises a body portion and a first outer portion extending axially from the body portion and having a diameter less than the diameter of the body portion, the outer portion defining the open end of the hollow axle casing; wherein the axial opening of the first wheel receives the first outer portion and is rotatable about the first outer portion; and wherein the first motor assembly is supported within the body portion of the casing and the first motor shaft extends axially through the first outer portion.

16. The assembly of claim 1 , wherein the hollow axle casing defines a second open end opposite the first open end, the assembly further comprising:

a second wheel having an axial opening for receiving a second portion of the hollow axle casing, the second wheel being rotatable about the second portion and substantially coaxially with the rotation of the first wheel; a second drive transfer plate engageably coupled to the second wheel; and a second motor assembly supported within the hollow axle casing, and coupled to a second motor shaft projecting through the second open end of the hollow axle casing to engage the second drive transfer plate, the second motor assembly providing a rotational force to the second motor shaft independently of the rotational force provided by the first motor assembly for causing rotation of the second drive transfer plate and the second wheel coupled thereto.

17. A truck assembly comprising:

an upper bracket having a plate portion for coupling the upper bracket to a skateboard deck, the plate portion defining a lengthwise direction and a plane, and at least one support member extending from a surface of the plate portion in a direction transverse to the plate portion plane; and

a pivot bracket having a lower portion for securing a wheel axle and having at least one extending member extending from the lower portion, the extending member being pivotally attached to the first support member to define an axis of pivot.

18. The truck assembly of claim 17, wherein the wheel axle supported by the lower portion is pivotal about the axis of pivot.

19. The truck assembly of claim 17, wherein the support member defines a guide slot, the extending member being attached to the support member at the guide slot and being slideable along the guide slot between at least a first and second position.

20. The truck assembly of claim 19, wherein the wheel axle is moveable between a first and second position defined by the guide slot.

21. The truck assembly of claim 17, wherein the extending member defines a guide slot, the support member being attached to the extending member at the guide slot and being slideable along the guide slot between at least a first and a second position.

22. The truck assembly of claim 17, further comprising:

a first resilient member coupled at a first end to the surface of the plate portion and coupled at a second end to the wheel axle; and a second resilient member coupled at a first end to the surface of the plate portion and coupled at a second end to the wheel axle, the first and second resilient members biasing the wheel axle to a neutral position wherein the wheel axle is substantially parallel to the plate portion plane.

23. The truck assembly of claim 22, wherein first and second resilient member extend obliquely from the surface of the plate portion

24. The truck assembly of claim 17, wherein the support member partially extend in the lengthwise direction, whereby the axis of pivot forms an angle with the plate portion plane.

25. The truck assembly of claim 17, wherein the support member extends substantially perpendicularly from the plate portion plane.

26. The truck assembly of claim 17, wherein the resilient members are coil springs.

27. The truck assembly of claim 17, wherein the second end of the first resilient extends through one of one or more openings in the wheel axle and is coupled to the interior of the wheel axle and the second end of the second resilient member extends through one of one or more openings in the wheel axle and is coupled to the interior of the wheel axle.

28. A skateboard comprising:

a first wheel;

a second wheel coaxial with the first wheel;

a first motor for providing rotational force to the first wheel;

a second motor for providing rotational force to the second wheel independently of the providing of force by the first motor to the first wheel; and

a controller configured for:

receiving user signals for controlling the first and second wheels; and controlling the providing of the rotational force to the first wheel by the first motor; and

controlling the providing of the rotational force to second wheel by the second motor independently of the controlling of the providing of the rotational force to the first wheel by the first motor.

29. The skateboard of claim 28, further comprising:

a third wheel;

a fourth wheel coaxial with the third wheel,

a third motor for providing rotational force to the third wheel independently of the providing of rotational force by the first, second, or fourth motors;

a fourth motor for providing rotational force to the fourth wheel independently of the providing of rotational force by the first, second, or third motors;

the controller further configured for;

controlling the providing of the rotational force to the third wheel by the third motor independently of the controlling of the providing of the rotational force by the first, second or fourth motors; and

controlling the providing of the rotational force to the fourth wheel by the fourth motor independently of the controlling of the providing of the rotational force by the first, second or third motors.

30. The skateboard of claim 28 or 29, wherein the motors are sensored brushless motors and the controller controls the providing of the rotational force by the motors by independently modulating current sent to the first and second motors.

31. The skateboard of claim 28, wherein user signals are wireless signals sent by a user-activated control device.

32. The skateboard of claim 31 , wherein the wireless signals are Bluetooth signals.

33. The skateboard of claim 28, further comprising a sensor for detecting the position of one or more body parts of a skateboard rider, wherein user signals comprise the detected position of one or more body parts.

34. The skateboard of claim 33, wherein the sensor is an infra-red sensor.

35. The skateboard of claim 28, further comprising one or more sensors for detecting the speed of rotation of the first and second motors, the controller being further configured to control the providing of rotational force to the first wheel by the first motor based on the detected speed of rotation of the first motor and to control the providing of rotational force to the second wheel by the second motor based on the detected speed of rotation of the second motor.