Patent Application
20240424831
This disclosure relates generally to a wheel assembly and a steering system for a vehicle, and in particular to a wheel assembly having an in-wheel motor.
Many vehicles used in the transportation industry release pollutants such as carbon dioxide into the atmosphere. The use of electric motors can help to reduce the harmful impact when operating a vehicle as they do not produce such pollutants. Electric motors can be relatively efficient, compact, reliable, lightweight, and quiet when compared with petrol, diesel or gas motors. Moreover, in some applications, the electricity required to operate the motor can advantageously be generated from a renewable supply.
Electric vehicles also provide the option of utilising in-wheel motors, where each wheel is configured with a complete drivetrain and braking system. In-wheel motors can precisely control the braking or motoring torque of a wheel on a millisecond timescale, and can therefore greatly improve traction and stability control whilst also reducing stopping distances and enhancing drivability and safety. In-wheel motors also allow for torque-vectoring. Torque-vectoring is when different torques are simultaneously applied to different wheels in order to improve traction and handling of the vehicle. This can be particularly advantageous when a vehicle is turning through a corner.
Despite advancement in the technical field, in-wheel motors face a number of technical challenges. For example, in-wheel motors require consideration of reducing the unsprung mass, protecting against road shocks, and protecting against heat from braking. These technical issues arise because the motor is carried inside each wheel, meaning that the motor operates in close proximity to the wheel itself, and the wheel must be configured to absorb the motors weight on its own.
In particular, in-wheel motors typically add unsprung weight, which is the mass of the components between the vehicle's suspension system and the road. This includes the in-wheel motor, the suspension, the wheels and all the other components that are directly connected to them such as wheel axles, wheel bearings, wheel hubs, tyres, as well as a portion of the weight of the drive shafts, springs, shock absorbers, and suspension links. The unsprung weight of a vehicle can adversely affect the handling of the vehicle due to the effects of inertia, causing the wheels to respond slower to changes in the road conditions. For example, in a fast moving vehicle travelling over a road bump, the greater the unsprung weight at each wheel, the more the inertia effects the accuracy and timeliness of the up and down movement of the wheel as it traverses the bump on the road surface. In vehicles where the unsprung weight is large, the suspension may be unable to fully absorb the impact force generated by the changing road conditions, instead transmitting the force into the vehicle chassis. In addition, the time of contact between the tyre and the ground can be reduced in some instances, which can reduce the efficiency with which the vehicle is able to accelerate, brake, or be steered.
Although careful tuning of the suspension can help to mitigate the effects of the large unsprung mass that are generally associated with in-wheel motors, there may remain a desire to minimise the unsprung mass where possible in order to improve the safety and performance of vehicle.
The applicant has determined that it would be advantageous to provide an improved wheel assembly and/or steering system that seeks to address or at least in part alleviate one or more problems identified above, or to provide the public with a useful choice.
In a first aspect, embodiments are disclosed of a wheel assembly. The wheel assembly comprises a wheel that is rotatable about a shaft. The wheel is supported by a plurality of connecting members to rotate about a plurality of motors that are arranged on the shaft. The plurality of motors are operable to control the connecting members so as to adjustably shift a central axis through the wheel relative to a central axis through the shaft. The wheel assembly may thus be used to dynamically adjust a position of the wheel axis relative to the central axis of the motors.
In the context of this specification, a rim of the wheel may in some forms be interpreted to define an inwardly facing edge or surface of a hollow wheel frame. For example, the inwardly facing rim of a wheel frame that has a tyre engaged therearound on the outwardly facing surface of the wheel frame, and spokes extending towards the shaft from the inwardly facing rim of the wheel frame. In other forms, a rim of the wheel may be interpreted to define an outer edge around the circumference of the wheel. For example, where the wheel is configured in a substantially solid disc-like manner, with a rim adapted around the circumference, and spokes engaged to a side wall of the disc-like wheel.
The wheel assembly may be configured as a hub-style wheel assembly that may be used as an active in-wheel suspension system, without requiring the addition of conventional suspension systems and the associate components to connect the suspension system to the wheel. This may result in the wheel assembly having reduced weight when compared to prior in-wheel motors. In some embodiments this may resolve, or at least somewhat alleviate, the unsprung weight issues that have historically been associated with in-wheel hub motors. The wheel assembly may, in some embodiments, also help to reduce the overall weight of the vehicle, as well as the cost of manufacture, by using motors to both drive the wheel and provide the suspension for the wheel in a compact arrangement.
In some embodiments, the plurality of motors may locate within the boundaries of the wheel. In some embodiments, the wheel assembly may comprise a control system that is configured to simultaneously control an acceleration and/or deceleration of each of the plurality of motors whereby, in use, the plurality of motors are operative in a communicative manner to rotate the wheel about the shaft.
In some embodiments, each of the plurality of motors may be controlled to accelerate and/or decelerate independently of the other motors of the plurality of motors, whereby in use a velocity of each of the plurality of motors is simultaneously variable. In some embodiments, each of the plurality of motors may be controlled to sinusoidally accelerate and decelerate during a single revolution of the wheel. In some embodiments, a timing of the sinusoidal acceleration and deceleration of an individual motor may be offset relative to the sinusoidal acceleration and deceleration of the other motors of the plurality of motors.
In some embodiments, the plurality of connecting members may be spokes that extend between the plurality of motors and the wheel, each spoke defining a motor linkage where the spoke is coupled to one of the plurality of motors, and a wheel linkage where the spoke is coupled to the wheel. In some embodiments, the spokes may be pivotable about each of the motor linkage and the wheel linkage. In some embodiments, each wheel linkage may be spaced equidistantly around a circumference of the wheel. In some embodiments, in use, a relative spacing between each of the plurality of motor linkages may be adjustable. In some embodiments, a single spoke may extend between the wheel and each of the plurality of motors.
In some embodiments, each of the spokes may be rigid.
In some embodiments, in use, an acceleration of one of the plurality of motors relative to the other motors of the plurality of motors may controllably orientate a corresponding one of the spokes that is attached to said one of the plurality of motors, whereby a distance between a corresponding motor linkage and the wheel is decreased.
In some embodiments, in use, a deceleration of one of the plurality of motors relative to the other motors of the plurality of motors may controllably orientate a corresponding one of the spokes that is attached to said one of the plurality of motors, whereby a distance between a corresponding motor linkage and the wheel is increased.
In some embodiments, in use, each one of the plurality of motors may be controlled to reach a peak velocity, respectively, when a corresponding one of the spokes that is attached to said one of the plurality of motors is at a position during each revolution that substantially corresponds to 90 degrees of a unit circle, whereby the rim of the wheel is adjusted to move downwards relative to the shaft.
In some embodiments, in use, each one of the plurality of motors may be controlled to reach a peak velocity, respectively, when a corresponding one of the spokes that is attached to said one of the plurality of motors is at a position during each revolution that substantially corresponds to 270 degrees of a unit circle, whereby the rim of the wheel is adjusted to move upwards relative to the shaft.
In some embodiments, the rim of the wheel may be restricted to movement in the Y-axis relative to the shaft.
In some embodiments, the wheel assembly may further comprise a mechanism that detects a state of the ground surface that contacts the wheel assembly in use, and communicates said state of the ground surface to the control system. The mechanism may in some embodiments be a sensor.
In some embodiments, in response to the detected state of the ground surface, the control system may control the acceleration and/or deceleration of each of the plurality of motors to adjustably shift the rim of the wheel relative to the shaft to effect a force dampening on the shaft and/or the wheel. In some embodiments, the mechanism may be an accelerometer.
In some embodiments, the assembly may comprise three motors.
In some embodiments, each of the plurality of motors may define a rotor and a stator that are arranged along the shaft, the shaft being aligned centrally through a centre of mass of each of the rotors and stators, and each rotor being arranged to rotate about the shaft relative to a corresponding stator.
In some embodiments, the rotor may comprise a plurality of magnets that are arranged to define a ring of magnets on each of the opposing sides of the stator.
In some embodiments, the stator may comprise a plurality of segments, the number of segments corresponding to the number of the magnets of one of the rings of magnets.
In some embodiments, a first half of the segments of the stator may be excited by a current to form a magnetic field of a first polarity and second half of the segments of the stator are excited by a current to form a magnetic field of an opposing second polarity.
In some embodiments, the current of a leading segment of the first half of the segments and a trailing segment of the second half of the segments of the stator may be reversible, whereby the magnetic fields are rotated to effect a rotation of the ring of magnets of the rotor.
In some embodiments, the plurality of motors may be arranged proximal to one another on the shaft such that the polarity of the ring of magnets of a first of the plurality motors is engaged to oppose the adjacent motors the polarity of the ring of magnets of an adjacent second of the plurality of motors.
In some embodiments, each motor linkage may be spaced equidistantly around a circumference of the plurality of motors when the plurality of motors operate at a common velocity.
In a further aspect, a wheel assembly is disclosed. The wheel assembly comprises a wheel that is rotatable about a shaft. The wheel is supported by a plurality of connecting members to rotate about a plurality of motors that are arranged on the shaft. The plurality of motors are operable to control the connecting members so as to adjustably shift a central axis through the wheel relative to a central axis through the shaft.
In a further aspect, a steering assembly for a wheel is disclosed. The steering assembly comprises a plurality of nested shells that are pivotally engaged to one another, the nested shells comprising at least a fixed outer shell and an innermost shell, and the wheel being arranged to rotate about a shaft that projects from the innermost shell. At least one of the nested shells is controllable to pivot relative to the fixed outer shell such that the angular position of the innermost shell, the shaft and the wheel are adjusted relative to the outer shell.
In some embodiments of the steering assembly, when the at least one of the shells is controlled to pivot relative to the fixed outer shell, a bearing surface between each shell may remain unexposed in use.
In some embodiments, the fixed outer shell may be shaped as approximately one quarter of a sphere, having a hollow substantially spherical shaped interior. In some embodiments, a pivot neck may protrude downwardly from a zenith of the substantially spherical shaped interior of the fixed outer shell.
In some embodiments, the steering assembly may comprise a first rotating shell that has a spherical cap shape, the first rotating shell being concentrically coupled to a bearing that is mounted to the interior of the fixed outer shell. In some embodiments a gap may be provided in a surface of the first rotating shell, the gap being arranged to receive the pivot neck therein, such that the first rotating shell is able to rotate relative to the outer shell unimpeded. In some embodiments, the steering assembly may further comprise a second rotating shell that has a spherical cap shape, the second rotating shell being arranged to rotate eccentrically relative to the first rotating shell. In some embodiments, the innermost shell may be configured such that a bearing that is mounted to an outwardly facing surface of the innermost shell is concentrically coupled to the second rotating shell.
In yet a further aspect of the present invention, there is provided a steering assembly for a wheel, the steering assembly comprising four or more linkages, the four or more linkages being arranged such that: a first linkage is pivotally coupled to a second linkage, defining a first pivot; a third linkage is pivotally coupled to the first linkage at a distance spaced away from the first pivot, defining a second pivot; a fourth linkage is pivotally coupled to the second linkage at a distance spaced away from the first pivot, defining a third pivot; and the third linkage and the fourth linkage are pivotally coupled to each other at a distance spaced away from each of the second and third pivots, respectively, defining a fourth pivot; wherein each of the first, the second, the third and the fourth pivots are arranged such that an axis through each of the pivots converges at a single origin.
In some embodiments, the first linkage may remain stationary, in use. In some embodiments, each of the four or more linkages may be substantially linear therealong. In some embodiments, each of the four or more linkages may be curved therealong.
In some embodiments, at least one of the first, the second, the third and the fourth pivots may comprise a bearing thereat. In some embodiments, each of the second and the third pivots comprise a bearing thereat, the bearings having a diameter whereby the bearing paths overlap in use so as to act as a substantially continuous structure, rather than having one structure cantilever off the other, and thereby may assist in distributing the load at the pivots across the bearings, which may improve the overall structural strength and integrity of the steering assembly.
In some embodiments, each of the first and third linkages may comprise at least one gear, the at least one gear of the first and third linkages being meshed together, whereby a rotation of the at least one first linkage gear in a first direction causes a rotation of the at least one third linkage gear in an opposing second direction. In some embodiments, the third linkage gear may be fixed relative to the third linkage. In some embodiments, the third linkage may be arranged to rotate concentrically about the second pivot relative to the first linkage. In some embodiments, the fourth linkage may be arranged to rotate eccentrically about the fourth pivot relative to the third linkage. In some embodiments, the second linkage may be arranged to rotate concentrically about the third pivot relative to the fourth linkage. In some embodiments, an angular rotation of the third linkage relative to the first linkage may cause an eccentric angular rotation of the fourth linkage in an opposing direction. In some embodiments, an angular rotation of the fourth linkage relative to the second linkage may cause an eccentric angular rotation of the second linkage relative to the first linkage.
In some embodiments, the first linkage may be able to pivot at least 180 degrees relative to the second linkage about the first pivot.
Other aspects, features, and advantages will become apparent from the following detailed description when taken in conjunction with the accompanying drawings, which are a part of this disclosure and which illustrate, by way of example, principles of inventions disclosed.
While aspects of the present invention will be described below for use in combination with each other in the preferred embodiments of the present invention, it is to be understood by a skilled person that some aspects of the present invention are equally suitable for use as standalone inventions that can be individually incorporated into apparatuses and systems for use with other types of wheel assemblies and steering systems not specifically described herein.
The accompanying drawings facilitate an understanding of the various embodiments.
Referring to the drawings, there is illustrated an embodiment of a wheel assembly 100. As would be appreciated by one skilled in the technical field, the wheel assembly 100 can be incorporated into a vehicle or any power-driven wheeled device, such as a motorised wheelchair. Where like reference numerals are used in the following description, the features are considered to be the same unless specified as being otherwise.
Referring to
The wheel 10 is supported relative to the shaft 12 about which it rotates by a plurality of connecting members in the form of spokes 18, 18′, 18″ which extend between each of the motors 20,20′,20″ that are arranged on the shaft 12 and the inner rim of the wheel 14, thereby linking the wheel 10 to the shaft 12. Each spoke 18, 18′, 18″ is coupled at a first distal end to one of the plurality of motors 20,20′,20″ to define a motor linkage 22,22′,22″, and coupled at the opposing second distal end to the inner rim of the wheel 14 defining a wheel linkage 24. A single spoke 18, 18′, 18″ extends from each of the plurality of motors 20,20′,20″ to engage the inner rim of the wheel 14. For example, with reference to the Figures, an embodiment of the wheel assembly 100 is shown having three spokes 18.18′, 18″ and three motors 20,20′,20″, with a first spoke 18 extending from a first motor 20, a second spoke 18′ extending from a second motor 20′, and a third spoke 18″ extending from a third motor 20″, where each of the three motors 20,20′,20″ are configured side by side to rotate concentrically about a single shaft 12. In a variation, two or more spokes can be arranged to extend from each of the plurality of motors, with each of the two or more spokes being equidistantly spaced around the singular motor from which they stem towards the wheel rim.
A control system, mounted on a control system board 80, is integrated with the wheel assembly 100 to individually control the operation of each of the plurality of motors 20,20′,20″ in real-time such that they can be operated to drive the rotation of the wheel 10 thereabout simultaneously, yet independently from one another. Each of the motors 20,20′,20″ can be independently controlled by the control system to accelerate, decelerate and/or maintain a velocity, such that the velocities of each motor 20,20′,20″ can be controlled to simultaneously be the same, or simultaneously be different, from each other. The control system coordinates the velocity and direction of rotation of each of the motors 20,20′,20″ such that the motors 20,20′,20″ operate via the control system in a communicative manner to rotate the wheel 10 about the shaft 12.
When each of the plurality of motors 20,20′,20″ are controlled to operate in unison at a substantially identical velocity, regardless of whether the wheel is accelerating, decelerating or maintaining a constant velocity, the central axis through the wheel 10 remains in a neutral configuration, where the central axis through the wheel 10 is concentric with the central axis through the shaft 12, and thus with each of the motors 20,20′,20″ (e.g.
The control system controls the motors 20,20′,20″ of the wheel assembly 100 independently of any other wheel assemblies 100 that are integrated with the vehicle. A centralised control system communicates with each wheel assembly 100 control system to direct each control system's individual operation, including, but not limited to, the acceleration and deceleration of the wheel 10, steering of the wheel assembly 100, brake control, traction control and stability control of the wheel assembly 100. In this manner, the wheel assembly 100 are operated as a collective in unison to drive the vehicle as a synchronised unit. In some forms, the independent control of the velocity of each wheel 10 of a vehicle can facilitate improved torque vectoring for the vehicle, where a unique torque force may be applied to each wheel 10 during cornering of the vehicle, whilst simultaneously increasing the velocity of any wheels 10 that locate on the outer side of the corner travelled. This may improve the predictability of the vehicle control.
The spokes 18, 18′, 18″ are rigid along their length, and are arranged to pivot relative to each of the motor 20,20′,20″ and the wheel 10 about each of the motor linkage 22,22′,22″ and wheel linkage 24, respectively. The relative location of the wheel linkages 24 are fixed relative to one another around the circumference of the wheel rim 14, with each wheel linkage 24 being spaced equidistantly therearound. However, the relative spacing between the motor linkages 22,22′,22″ of each of the different motors 20,20′,20″ around the circumference of the motors 20,20′,20″ is able to be adjustably lengthened or shortened when the velocity of an individual motor of the plurality of motors 20,20′,20″ differs from the velocity of one or more of the other motors of the plurality of motors 20,20′,20″ during a single revolution of the wheel 10. For example, if the first motor 20 accelerates whilst the second motor 20′ either accelerates at a lesser rate, maintains its velocity, or decelerates, the relative distance between the first motor linkage 22 and the second motor linkage 22′ will change accordingly whilst the relative instant velocities of rotation of each motor 20,20′ remain different.
During operation of the wheel assembly 100, the control system can direct each of the plurality of motors 20,20′,20″ to sinusoidally accelerate and decelerate during a single revolution of the wheel 10, with the sinusoidal acceleration and deceleration of an individual motor of the plurality of motors 20,20′,20″ being at a different time to the other motors of the plurality of motors 20,20′,20″, whilst enabling each individual motor to achieve a peak and/or trough velocity at substantially the same angular position as the other motors of the plurality of motors 20,20′,20″ during a revolution of the wheel 10. The sinusoidal acceleration and deceleration of an individual motor of the plurality of motors 20,20′,20″ is thus offset relative to the sinusoidal acceleration and deceleration of the other motors of the plurality of motors 20,20′,20″, with the precise phase of the acceleration and deceleration being defined by the control system.
An acceleration of one of the motors 20,20′,20″ relative to the other motors 20,20′,20″ can cause the rigid spoke 18, 18′, 18″ attached to that motor 20,20′,20″ to pivot about both the corresponding motor linkage 22,22′,22″ and wheel linkage 24. As the wheel linkages 24 are fixed to remain equidistantly angularly spaced around the circumference of the wheel rim 14, as the motor linkage 22,22′,22″ of the accelerating motor 20,20′,20″ increases the relative angular distance between it and the motor linkage 22,22′,22″ of the trailing motor 20,20′,20″, the corresponding spoke 18, 18′, 18″ between the motor linkage 22,22′,22″ of the accelerating motor 20,20′,20″ and corresponding wheel linkage 24 is urged to orient to increase the relative angular distance between the motor linkage 22,22′,22″ of the accelerating motor 20,20′,20″ and corresponding wheel linkage 24 so as to compensate for the differential in relative velocities. The orientation of the pivoting spoke 18, 18′, 18″ acts to collapse the wheel linkage 24 towards the shaft 12, decreasing the distance between the wheel rim 14 and the motors 20,20′,20″ at that angular position during a single revolution of the wheel 10.
In a similar manner, as the motor linkage 22,22′,22″ of a decelerating motor 20,20′,20″ decreases the relative angular distance between it and the motor linkage 22,22′,22″ of the trailing motor 20,20′,20″, the corresponding spoke 18, 18′, 18″ between the motor linkage 22,22′,22″ of the accelerating motor 20,20′,20″ and corresponding wheel linkage 24 is urged to orient to decrease the relative angular distance between the motor linkage 22,22′,22″ of the accelerating motor 20,20′,20″ and corresponding wheel linkage 24 so as to compensate for the differential in relative velocities. In this instance, the orientation of the pivoting spoke 18, 18′, 18″ acts to pull the wheel linkage 24 in order to extend away from the shaft 12, increasing the distance between the wheel rim 14 and the motors 20,20′,20″ at that angular position during a single revolution of the wheel 10.
Thus, by controllably adjusting the phase of the sinusoidal cycles of each of the plurality of motors 20,20′,20″, the angular position where each of the motors 20,20′,20″ achieves a peak and/or a trough velocity during a revolution of the wheel 10 can be defined by the control system. The control system can thus operate the plurality of motors 20,20′,20″ to dynamically control and adjust the relative distance between wheel rim 14 and the shaft 12 by shifting the position of the central axis through the wheel 10 relative to a central axis through the shaft 12 and motors 20,20′,20″. The operation of the motors 20,20′,20″ at varying velocities simultaneously, can controllably adjust the orientation of the spokes 18, 18′, 18″ as they rotate about the shaft 12, thereby shifting the central axis through the wheel 10 relative to a central axis through the shaft 12 to the position determined by the control system. The magnitude of the shift in position of the central axis through the wheel 10 relative to a central axis through the shaft 12 can be controllably adjusted by the control system by driving each of the motors 20,20′,20″ to rotate through a sinusoidal cycle with a greater amplitude of acceleration and deceleration during a single revolution of the wheel 10.
In some forms, the control system can dynamically control the position of the central axis through the wheel 10 relative to a central axis through the shaft 12 in any of the 360 degrees around the shaft 12, providing a full range of relative motion along both the X-axis X-X and Y-axis Y-Y of the wheel assembly 100, and only limited by the relative diameters of the wheel rim 14 and motors 20,20′,20″.
The spokes 18, 18′, 18″ can define a curved body that can facilitate a close engagement of the spoke 18, 18′, 18″ with one or both of the inwardly facing surface of the wheel rim 14 and the outer surface of one or more of the plurality of motors 20,20′,20″ when the distance between the wheel rim 14 and the motors 20,20′,20″ is decreased in use. The curved body can help the spokes 18, 18′, 18″ to generally conform with the curvature of the wheel rim 14 whilst folding towards, and wrapping over, the motors 20,20′,20″.
In some forms, the spokes 18, 18′, 18″ can be formed to have a width at the motor linkage 22,22′,22″ end of the spokes 18, 18′, 18″ that is slightly wider than the cumulative width of the plurality of motors 20,20′,20″ as they are arranged side by side on the shaft 12. A supporting plate can be arranged to spin freely on the shaft 12, with a supporting plate being located adjacent to on one or both ends of the shaft 12 one either side of the plurality of motors 20,20′,20″. The motor linkage 22,22′,22″ can thus be linked to, and supported by, a respective one of the motors 20,20′,20″ in addition to the supporting plate/s, thereby strengthening the joint. In some forms, permanent magnets can be mounted within the supporting plate/s to assist with balancing the opposing forces of the various magnets within the plurality of motors 20,20′,20″, for example, such that the forces in each of motors 20 and 20″ are balanced with that of motor 20′.
Referring now to
Each motor 20,20′,20″ can be connected to a limiter rotor 34 via a respective one of a plurality of linkages 32,32′,32″ that are arranged behind the motors 20,20′,20″, on the vehicle facing inner side of the wheel assembly 100. The linkages 32,32′,32″ link the motors 20,20′,20″ to a disc-shaped limiter rotor 34 which is arranged to revolve around a limiter hub 36. The limiter hub 36 in turn is constrained by a mechanical limiter 30 to motion along the Y-axis Y-Y in line with a central axis through the shaft 12, with the mechanical limiter 30 being configured to pivot up and down about a pin 31 that lies parallel to the X-axis X-X and is fixed in alignment with the central axis through the shaft 12. The mechanical limiter 30 thus acts to restrict the central axis through the wheel 10 against movement along the X-axis X-X, allowing only movement along, and in alignment with, the Y-axis Y-Y that passes through the central longitudinal axis through the shaft 12.
In use, the control system of the wheel assembly 100 can thus operate the motors 20,20′,20″ to determine the position of the central axis through the wheel 10 relative to a central axis through the shaft 12 along, and in alignment with, the Y-axis Y-Y. When each of the plurality of motors 20,20′,20″ are operated simultaneously at the same velocity, the wheel assembly 100 maintains a neutral configuration where the central axis through the wheel 10 aligns concentrically with the central axis through the shaft 12 (e.g.
In some forms, each linkage 32,32′,32″ has a longitudinal length that equates to approximately half the longitudinal length of the spokes 18, 18′, 18″. A first distal end of each linkage 32,32′,32″ pivotably engages a respective one of the motors 20,20′,20″ via an extended portion of the respective motor linkages 22,22′,22″, with the pivot point of the extended portion of the respective motor linkages 22,22′,22″ being at a radial length C-C from the central axis of the motors 20,20′,20″ that equates to approximately half the radius D-D of the motors 20,20′,20″. An opposing second distal end of each linkage 32,32′,32″ pivotably engage the limiter rotor 34 at a radial length A-A from the central axis of the shaft 12 that equates to approximately half the radial distance B-B of the wheel linkage 24 from the central axis of the shaft 12.
In some forms, the limiter rotor 34 is configured to function as a disc brake, with a brake rotor 35 and calliper 37 assembly mounted thereto in order to provide smooth mechanical braking for the wheel assembly 100. Although in some forms the motors 20,20′,20″ can be configured to produce regenerative braking force, the addition of a mechanical braking assembly can be used to compliment the regenerative braking system and help improve the safety of the vehicle operation should the regenerative braking system fail. Similarly, the mechanical limiter 30 can act as an additional safety control in instances where the control system or motors 20,20′,20″ experience a failure whilst the vehicle is moving, as the limiter can retain the wheel 10 from movement along the X-axis X-X which could compromise vehicle control.
A regenerative braking system, when incorporated with the wheel assembly 100, may improve the range of distance with which the vehicle distance can travel. Any electrical power generated from the regenerative braking system can be supplied back to the main vehicle power supply, located external from the wheel assembly 100, for example to a battery and/or a super capacitor that are integrated with the vehicle chassis.
The wheel assembly 100 further comprises one or more sensors, not shown, that are configured to detect the state of the ground surface surrounding the vehicle, and in particular the ground surface forward of the wheel assembly 100 that is anticipated to imminently come into contact with the wheel 10. These sensors can be configured to detect a variety of inputs including, but not limited to, the relative distance between each corner of the vehicle chassis and the ground surface beneath the vehicle chassis, the topology of the ground surface forward of the moving vehicle and each wheel assembly 100, the acceleration and g-forces experienced by an occupant of the vehicle cabin, and when an impact with an external object is imminent. The sensor/s can communicate the detected state of the ground surface directly and in-real time to the control system of the relevant wheel assembly 100. In some forms, the sensed data can be communicated by the one or more sensors in-real time to the centralised control system. The centralised control system can centrally collate all of the sensor data, and then process the data in order to compute and determine if any corrective actions are required in-real time by one or more wheel assembly 100 in order to improve the operation of the vehicle.
For example, in some forms the one or more sensors can include an accelerometer that is configured to measures the acceleration forces acting on the wheel assembly 100, in order to detect the roll, yaw and position in space of the wheel 10 in real time. The data detected by the accelerometer can be processed in real time by the control system, or centralised control system. In turn, the control system, or centralised control system, can controllably direct the motors 20,20′,20″ to instantaneously, and in real-time, begin to oscillate sinusoidally between acceleration and deceleration during a single rotation of the wheel 10. The control system, or centralised control system, can controllably time the peak and/or a trough velocity of each motor in an offset manner, whilst positioning the peak and/or a trough velocity at an angular position of the revolution of the motors 20,20′,20″ whereby the phase of the sinusoidal oscillations determines whether the position of the central axis through the wheel 10 relative to the central axis through the shaft 12 is adjustably shifted upwards towards an elevated configuration of the wheel assembly 100 (e.g.
In some forms, the active suspension of each wheel assembly 100 of the vehicle can be proactively used to adjustably control the pitch and roll of the vehicle in order to shift the centre of mass of the vehicle during cornering. This may be used to effectively equalise the forces applied to the wheels 10 of the vehicle by the ground surface as the vehicle travels through the curved trajectory of the bend or corner, thereby optimising the grip of each of the wheels 10 against the ground surface. By using a plurality of in-wheel motors 20,20′,20″ to simultaneously effect both the drive of the vehicle and the active suspension of an individual wheel 10, the singular set of in-wheel motors 20,20′,20″ can serve a dual purpose whilst helping to reduce the overall weight and bulk of the vehicle.
In a variation, the wheel assembly can comprise two motors that are arranged side by side on the same shaft, with one spoke extending from each of the motors to support the wheel therearound. In a further variation, the wheel assembly can comprise two motors that each have two spokes extending away therefrom from diametrically opposed sides of the motors. In yet a further variation, the wheel assembly can comprise four motors that are arranged side by side on the same shaft. As would be appreciated by one skilled in the technical field, numerous further variations are contemplated within the scope of the present disclosure.
In some forms, it may be preferable for the wheel assembly to utilise an even number of spokes. In some forms, an even number of spokes may improve the smoothness with which the wheel assembly can be operated, as each spoke can be balanced against an opposing spoke on the same motor, or on a different motor, as the inertia from a first motor accelerating can be substantially balanced out by the inertia of an opposing deceleration of a second motor.
Referring now to
Starting with the motors 20,20′,20″ and wheel 10 of the wheel assembly 100 at rest in the first stage 81, the relative position 96 of the central axis through the wheel 10 is held in the neutral configuration (e.g.
At the second stage 82, the control system begins to controllably operate the plurality of in-wheel motors 20,20′,20″, directing them to steadily accelerate in unison until the angular velocity of rotation of the wheel 94 reaches the desired magnitude (e.g. 180 degrees per second). At the third stage 83, the plurality of motors 20,20′,20″, continue to rotate in unison at the desired angular velocity 94, thereby maintaining the wheel 10 at the same constant angular velocity 94. During the second 82 and third stages 83, the operation of each of the plurality of motors 20,20′,20″ is synchronised such that the each of the plurality of motors 20,20′,20″ drives the wheel rim 14 with the same torque and angular velocity 94 in unison. The relative position 96 of the central axis through the wheel 10 is thus maintained in the neutral configuration.
At the fourth stage 84, the control system controllably adjusts the operation of each of the motors 20,20′,20″ individually, directing them to begin to sinusoidally accelerate and decelerate at individually offset timing phases. For example, the control system could initiate such an operation in response to a detected state of the ground surface forward of the wheel assembly 100, such as a protrusion, in order to effectively provide active suspension to the wheel assembly 100. Although the individual motors 20,20′,20″ accelerate and/or decelerate, the resulting cumulative effect of the sinusoidal oscillations being at offset phases is that the angular velocity of rotation of the wheel 94 remains the same as in the third stage 83. However, as each motor 20,20′,20″ is controlled to reach a peak velocity 93,93′,93″ in an offset manner as the corresponding spoke 18, 18′, 18″ rotates through the lowest point of the revolution (e.g.
At the sixth stage 86, the control system controllably adjusts the magnitude and phase of the sinusoidal acceleration and deceleration of each of the motors 20,20′,20″ individually, shifting the timing and angular position of the peak 93,93′,93″ and trough 92,92′,92″ angular velocities of each motors 20,20′,20″, respectively, such that each motor 20,20′,20″ reaches a peak velocity as the corresponding spoke 18, 18′, 18″ rotates through the highest point of the revolution (e.g.
At the ninth stage 89, the plurality of motors 20,20′,20″, again rotate in unison at the desired angular velocity 94, thereby maintaining the wheel 10 at the same constant angular velocity 94. The operation of each of the plurality of motors 20,20′,20″ is again synchronised such that the each of the plurality of motors 20,20′,20″ drives the wheel rim 14 with the same torque and angular velocity 94 in unison. The relative position 96 of the central axis through the wheel 10 is maintained in the neutral configuration.
At the tenth stage 90, the control system begins to steadily decelerate the plurality of in-wheel motors 20,20′,20″ in unison until the angular velocity of rotation of the wheel 94 returns to zero and the wheel 10 is at rest. The relative position 96 of the central axis through the wheel 10 is again held in the neutral configuration, where it is aligned to be concentric with that of the central axis through the shaft 12. This continues into the eleventh stage 81′, which replicates the first stage 81.
Referring now to
In some forms, each motor 20,20′,20″ can be an axial flux motor that is arranged as a brushless twelve-phase DC motor. The rotor 40 comprises a plurality of permanent magnets 41 that are arranged to define a ring of magnets adjacent each of the opposing sides of a copper stator 42, so as to balance the magnetic forces on either side of the stator 42. The central axis though each ring of magnets aligns concentrically with the axis through the shaft 12. The stator 42 is arranged in plurality of parallel planar segments 43. In some forms, each ring of magnets of the rotor 40 may comprise the same quantity of magnets 41 as the quantity of segments 43 of the corresponding stator 42. Half of the segments 43 are configured to be excited by a current within the stator 42 segments 43 that forms a magnetic field therearound having a first polarity. The other half of the segments 43 are configured to be excited by a current within the stator 42 segments 43 that forms a magnetic field of an opposing second polarity therearound. For example, in some forms, the stator 42 may comprise twenty four copper segments 43, where twelve of the segments 43 can be excited to form a magnetic field having a positive polarity, whilst the other twelve copper segments 43 are excited to form a magnetic field having a negative polarity. The current within the stator 42 segments 43 is generated from a power source stored within the vehicle chassis (e.g. the car battery). The current is distributed from the power source by the centralised control system to the individual wheel assemblies 100 of the vehicle, and then by the individual control system to the stator segments 43 through conduits in the shaft 12.
The permanent magnets 41 in each ring of magnets are arranged whereby the surface facing towards, and proximally adjacent to, the segments 43 provide a magnetic field having an opposing polarity to that of the magnetic field around the segments 43 of the stator 40. By reversing the current on the leading 43′ and trailing 43″ segments of the stator 42, the magnetic field within the segments 43 of the stator 42 can be rotated about the shaft 12. As the magnetic field within the segments 43 is rotated, the magnetic field within the permanent magnets 41 of the rotor 40 is urged to simultaneously rotate in order to return the opposing magnetic fields to a position in which the polarities of the adjacent magnetic fields facilitates a magnetic attraction force therebetween. The control system can thus drive the angular velocity rotation of the rotor 40 of each of the plurality of motors 20,20′,20″ by controllably reversing the current on the leading 43′ and trailing 43″ segments of the stator 42 in order to rotate the magnetic field within the segments 43 at the desired angular velocity.
The permanent magnets 41 of the rotor 40 are positioned such that they also generate a magnetic field on the outer facing side of each rotor 40. The magnetic field of a first rotor 40 is positioned such that it acts in opposition to, and repels, the magnetic field generated by an adjacent second rotor 40. The permanent magnets 41 are thus configured so as to effectively replicate the functional performance of torsional springs between the rotors 40 of adjacent motors 20,20′,20″, whereby, when the motors 20,20′,20″ are at rest the opposing magnetic fields resiliently rotate the rotors 40 so as to return the corresponding spokes 18, 18′, 18″ to their at-rest starting position. In some forms, the rotor magnetic fields can be configured whereby the rotors 40 of the plurality of motors 20,20′,20″ are inclined to return the wheel assembly 100 to the neutral configuration with the spokes 18, 18′, 18″ located in a substantially equidistant spacing around the circumference of the plurality of motors 20,20′,20″ when the plurality of motors operate at a common velocity. The common velocity can be a common angular velocity of zero or greater, whether the motors 20,20′,20″ are accelerating, decelerating, or maintaining the velocity. For example, where there are three spokes the spacing can be 120° apart. In some forms, depending on the strength of the permanent magnets 41 used in the rotor 40 it may be necessary to integrate one or more resilient springs, or a hydraulic cylinder 75 and accompanying piston, that engages and lifts the mechanical limiter 30 along the Y-axis Y-Y, whereby the spring/s or hydraulic cylinder and piston are configured to act as an auxiliary support for the permanent magnets 41 and assist with resiliently returning and maintaining the wheel assembly 100 to the at-rest starting position and neutral configuration where the central axis through the wheel 10 is concentric to the central axis through each of the motors 20,20′,20″.
In some forms, one or more sensors can be located on the stator 42 proximal the rotor 40, with the sensor/s being configured to detect the orientation of the rotor 40 by measuring variations in the magnetic field. In some forms, the sensor/s can be used to measure angular velocity of an individual motor 20,20′,20″. In some forms, one or more sensors be located on the stator 42, with the sensor/s being configured to detect a temperature within the respective motor 20,20′,20″. The electrical wiring that provides current to each of the stator segments 43 and the one or more sensors within each of the stators 40 can be ducted through the shaft 12 of the wheel assembly 100 in order to communicate with the control system.
For example, a Hall effect sensor can be located proximal to each rotor, and a temperature sensor can be installed within each stator. The Hall effect sensors are statically fixed relative the stator 42, and configured to detect the relative presence and magnitude of the magnetic field of the adjacent permanent magnets 41 of the ring of magnets of the rotor 40. The control system can translate the communicated output voltage of the Hall effect sensor, which is directly proportional to the strength of the magnetic field, in order to calculate the relative position and thus rotational velocity, rotational direction, and y-axis position of each of the rotors 40, the motors 20,20′,20″ and thus the wheel rim 14. The communicated information from each of the Hall effect and temperature sensors can be processed by the control system and compared against pre-determined limits. The control system can thus process if one or more of the motors is stalling and/or over-heating, and take preventative action if required. The Hall effect and temperature sensors can communicate any detected information to the control system, whereby the control system can, in response, controllably adjust the angular velocity of the rotation of the magnetic field around the stator 42, or alternatively, adjustably control the amount of electrical current that is provided to the stator segments 43 in order to increase or decrease the magnetic field strength, as required.
The sensor/s may assist the control system in maintaining a synchronised rotation of the magnetic field around the permanent magnets 41 of the rotor 40 with the rotating magnetic field of the stator 42. The sensor/s may also assist the control system in preventing the motors 20,20′,20″ of the wheel assembly 100 from over-heating. For example, in some forms when the vehicle is being driven to travel up a sloped ground surface an increased torque load may be applied against the wheel 10 which acts to reduce the speed of rotation of the rotor 40 relative to the rotational speed of the magnetic field around the stator 42. In such instances, the one or more Hall Effect sensors can communicate the reduction in relative angular velocity between the magnetic field around rotor 40 and the magnetic field around the stator 42 to the control system. The control system, in response, can counteract the increased torque by either controllably increasing the magnitude of the magnetic field strength around the stator 42 by increasing the electrical current therein, or controllably reduce the rotational speed of the magnetic field around the stator 40 such that the relative angular velocity between the magnetic field around the rotor 40 and the magnetic field around the stator 42 remains substantially synchronised.
The control system can also use the received information from each Hall effect sensor to calculate in-real time if a change in the y-axis position is required or if the y-axis position should be maintained, by comparing the calculation of the actual y-axis position from each Hall effect sensor with the required y-axis position. The control system can then control the y-axis position such that it is changed or maintained in real-time, in response to the determined differential between the calculated y-axis position and the required y-axis position.
The centralised control system collects the information communicated thereto by the control system of each of the wheel assemblies 100 of the vehicle. The centralised control system can process and compare the information from a single wheel assembly 100 with the information gathered from each of the other wheel assemblies 100 of the vehicle. The centralised control system can use this information to assist in identifying the status of a specific wheel assembly 100. For example, the information collected by the centralised control system can be processed to identify instances where a specific one of the wheel assemblies 100 has experienced a loss of traction, or to calculate the relative force of each wheel 10 on the road. The centralised control system can also use the collected information to calculate the overall velocity of the vehicle. The centralised control system can also use the collected information, for example from the accelerometer, to identify any undulations in the surface beneath a wheel assembly 100, calculate the distance between the wheel 10 and the ground surface, and ascertain the relative level of each wheel 10 of the vehicle. Data inputs from other sensors that are spaced around the vehicle chassis, such as accelerometers and road topology scanners, can be used in conjunction with the sensors of the wheel assembly 100 to complement the information communicated by the control system of an individual wheel assembly 100. This can assist the centralised control system with collating a high level of detail regarding the vehicle's surroundings. The centralised control system can use this information to assist with optimising the safety, comfort, and efficiency of the vehicle. For example, the centralised control system can utilise the data to controllably adjust the y-axis position of one or more of the wheels 10 in order to maintain a substantially level relative pitch and roll angle for the vehicle, thereby facilitating active suspension of the vehicle.
The control system can be housed between the inner two shells of the wheel assembly 100, adjacent a distal end of the shaft 12. This may help to reduce the amount of cabling that is required within the wheel assembly 100. The control system is in wired communication with a power supply that is located externally from the wheel assembly 100 and can be wired to communicate with the centralised control system, also located externally from the wheel assembly 100, in order to exchange information regarding the individual wheel assembly 100. In some forms, the control system can be configured to communicate wirelessly and in-real time with the centralised control system. Where required, the cabling from the control system can be fed out from the wheel assembly 100 into the chassis of the vehicle via the pivot neck 72 about which the wheel assembly 100 is steered.
Referring now to
For example, the wheel assembly 100 can comprise a steering assembly 60 comprised of four concentric partially spherical or hemispherical shells, with each shell being configured to pivot relative to the other shells, without exposing the bearing surfaces. In some forms, the bearings about which each shell is configured to pivot can utilise a bearing seal, without requiring a protective rubber boot thereat.
Referring to
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Referring again to
The shells of the steering assembly 60 are inherently strong due to their substantially spherical shape, thereby allowing for the shells to be formed from less material which may reduce the overall weight and space required. Each shell of the steering assembly 60 is designed as a relatively lightweight and relatively compact casing that is adapted to distribute the steering loads of the wheel assembly 100 more evenly, whilst minimising the stress forces at each of the connection points therebetween. The shells of the steering assembly 60 are nested into each other in a compact manner and partially wrap around the wheel 10, motors 20,20′,20″ and shaft 12, so as to closely conform to the space that the wheel 10 and motors 20,20′,20″ occupy, thereby reducing the overall size of the wheel assembly 100. The gaps between each shell of the steering assembly 60 may be adapted to provide a large surface areas for heat sinks.
The structure of the disclosed steering assembly 60 is configured to distribute the dynamic load applied between the wheel assembly 100 and the vehicle chassis away from the singular pivot neck 72 about which the wheel assembly 100 is angularly rotated during steering of the vehicle. Referring to
In order to rotate the wheel linkage 68′ angularly about the primary pivot 50 relative to the static linkage 62′ the first rotating linkage 64′ is controlled to rotated about the first pivot 51 so as to drive second rotating linkage 66′ to rotate about each of the second and third pivots 52,53 and thereby adjust the relative angular position of the wheel linkage 68′ relative to the static linkage 62′. Such an arrangement is able to more efficiently support and distribute the dynamic load away from the primary pivot 50 whilst pivoting the wheel linkage 68′ relative to the static linkage 62′, as each of the spaced pivot points 50,51,52,53 are arranged such that an axes passing through each respective one of the pivot points 50,51,52,53 is angled to converge at a single point of origin. By reducing the magnitude of the dynamic point loads borne at the primary pivot 50, and spreading these forces more evenly across a plurality of linkages and pivots, the size of the bearings used to facilitate the pivoting motion can be reduced.
Referring to
As would be appreciated by one skilled in the art, in a similar manner, each of the first, second and third rotating shells 64,66,68 respectively are configured to rotate about a set of axes that pass through an origin that is concentric to each of the partially spherical or hemispherical shells of the steering assembly 60, with the axes radiating in three-dimensions. Thus, the first 64 and second 66 rotating shells are configured to swivel eccentrically relative to one another, despite the respective axes through each internal shell being arranged so as to align with a central axis through the shells.
As would be appreciated by one skilled in the art, numerous alternative steering assemblies are possible based on the same principle. Referring to
Furthermore, as would be appreciated by one skilled in the art, the linkages of the steering assembly do not need to be curved or define a substantially spherical-looking steering assembly. The principle behind the steering assembly, as explained above, can be applied to alternative geometric shapes that have converging axes that restrict the freedom of movement based on the axes of the primary pivot.
For example, with reference to
The principles disclosed above in relation to the steering assembly 60 can also be extended to applications beyond vehicle wheel steering to axial positioning in general. For example, additional applications may include, but are not limited to, slewing pivot assemblies for cranes and excavation machinery, gimbal assemblies for cameras, radar dishes, and two axis joints for robotics etc.
In the foregoing description of preferred embodiments, specific terminology has been resorted to for the sake of clarity. However, the invention is not intended to be limited to the specific terms so selected, and it is to be understood that each specific term includes all technical equivalents which operate in a similar manner to accomplish a similar technical purpose. Terms such as “front” and “rear”, “inner” and “outer”, “above”, “below”, “upper” and “lower” and the like are used as words of convenience to provide reference points and are not to be construed as limiting terms.
The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as, an acknowledgement or admission or any form of suggestion that prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates.
In this specification, the word “comprising” is to be understood in its “open” sense, that is, in the sense of “including”, and thus not limited to its “closed” sense, that is the sense of “consisting only of”. A corresponding meaning is to be attributed to the corresponding words “comprise”, “comprised” and “comprises” where they appear.
The word “about” or “approximately” when used in relation to a stated reference point for a quality, level, value, number, frequency, percentage, dimension, location, size, amount, weight or length may be understood to indicate that the reference point is capable of variation, and that the term may encompass proximal qualities on either side of the reference point. In some embodiments, the word “about” may indicate that a reference point may vary by as much as 30 percent.
As used herein, the word “substantially” may be used merely to indicate an intention that the term it qualifies should not be read too literally and that the word could mean “sufficiently”, “mostly” or “near enough” for the patentee's purposes.
In addition, the foregoing describes only some embodiments of the invention(s), and alterations, modifications, additions and/or changes can be made thereto without departing from the scope and spirit of the disclosed embodiments, the embodiments being illustrative and not restrictive.
Furthermore, invention(s) have been described in connection with what are presently considered to be the most practical and preferred embodiments, it is to be understood that the invention is not to be limited to the disclosed embodiments, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the invention(s). Also, the various embodiments described above may be implemented in conjunction with other embodiments, e.g., aspects of one embodiment may be combined with aspects of another embodiment to realize yet other embodiments. Further, each independent feature or component of any given assembly may constitute an additional embodiment.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2021903179 | Oct 2021 | AU | national |
| 2021904271 | Dec 2021 | AU | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/AU2022/051184 | 10/5/2022 | WO |
