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Title:
A MOTOR VEHICLE WITH TILTING WHEELS
Document Type and Number:
WIPO Patent Application WO/2020/041836
Kind Code:
A1
Abstract:
A motor vehicle (10) is disclosed having a chassis (201) with a longitudinal centre line (16) and a vehicle vertical plane through which the longitudinal centre line passes. The vehicle (10) has first and second wheels (12L,12R) on respective opposite sides of the longitudinal centre line (16). A coupling system (18) couples the first and second wheels (12L, 12R) to the chassis (201) in a manner to enable the wheel (12L) and (12R) to: tilt in unison relative to the vehicle vertical plane; and, turn in unison with the wheels remaining parallel with each other.

Inventors:
WYATT STEPHEN (AU)
Application Number:
PCT/AU2019/050918
Publication Date:
March 05, 2020
Filing Date:
August 29, 2019
Export Citation:
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Assignee:
DESTEC PTY LTD (AU)
International Classes:
B60G21/05; B60G3/20; B60G7/00; B62D7/14; B62D9/04
Foreign References:
US20070075517A12007-04-05
US20130168934A12013-07-04
US20170252637A12017-09-07
Attorney, Agent or Firm:
GRIFFITH HACK (AU)
Download PDF:
Claims:
CLAIMS

1. A motor vehicle comprising:

a chassis having a longitudinal centre line and a vehicle vertical plane through which the longitudinal centre line passes;

first and second wheels on respective opposite sides of the longitudinal centre line; and

a coupling system that couples the first and second wheels to the chassis, the coupling system arranged to enable the respective wheel to: tilt in unison relative to the vehicle vertical plane; and, turn in unison with respective wheels remaining parallel with each other.

2. The motor vehicle according to claim 1 wherein coupling system includes a respective knuckle hub for each of the first and second wheels, wherein each wheel is rotatably coupled to a corresponding knuckle hub; each knuckle hub having respective first joints at each of two diametrically locations opposite a centre point of a corresponding wheel coupling the knuckle hub to the chassis.

3. The motor vehicle according to claim 2 wherein the first joint includes a first pin

capable of pivoting about a first pivot axis and a second pin pivotally coupled to the first pin about a second pivot axis orthogonal to the first pivot axis and wherein the second pin is coupled to the chassis.

4. The motor vehicle according to claim 3 wherein the coupling system includes for each wheel an upper structure and a lower structure, each structure coupled at one end to the chassis and at an opposite end to a respective first pin by an associated second pin about the second pivot axis.

5. The motor vehicle according to claim 4 wherein the one end of each structure is

coupled to the chassis about a structure pivot axis that lies parallel to the longitudinal centre line.

6. The motor vehicle according to claim 4 or 5 wherein the coupling system includes a tilt system operable to tilt the first and second wheels relative to the vehicle vertical plane, the tilt system arranged to move the upper and lower structures laterally of the longitudinal centre line.

7. The motor vehicle according to claim 6 wherein the tilt system comprises an actuator coupled with the upper and lower structures and arranged to move the upper and lower structures laterally of the longitudinal centreline in response to one or more input signals.

8. The motor vehicle according to claim 7 wherein the tilt system comprises a control shaft extending along with the longitudinal centreline and coupled to the upper and lower structures and wherein the actuator is operable to rotate the control shaft about an axis parallel to the longitudinal centreline.

9. The motor vehicle according to claim 8 wherein the tilt system comprises at least one linkage member fixed to the control shaft and pivotally coupled at opposite ends to the upper and lower structures.

10. The motor vehicle according to claim 9 wherein the tilt system comprises two linkage members each fixed to the control shaft at location spaced along the longitudinal centre line.

1 1 . The motor vehicle according to claim 10 wherein the upper and lower structures each comprise a respective wishbone, and wherein each wishbone is connected at one end to both of the linkage members.

12. The motor vehicle according to claim 1 1 wherein the tilt system comprises an actuator coupled to the control shaft, wherein the actuator is arranged to rotate the control shaft about an axis parallel to the longitudinal centre line in response to input signals received from sensors on the vehicle, a driver of the vehicle, or both sensors and the driver.

13. The motor vehicle according to any one of claims 2-12 including a steering mechanism coupled with the first and second wheels and capable of steering the first and second wheels independent of an angle of tilt of the wheels.

14. The motor vehicle according to claim 13 wherein the knuckle hub includes for each of the first and second wheels, a respective steering joint coupled with the steering mechanism and arranged to provide three degrees of freedom of motion between a steering mechanism and the knuckle hub.

15. The motor vehicle according to claim 14 wherein each steering joint comprises a first pin capable of pivoting about a first steering axis to provide a first degree of freedom of motion; and, coupled to the steering mechanism about a second steering pivot axis orthogonal to the first steering axis to provide a second degree of freedom of motion.

16. The motor vehicle according to claim 15 wherein the first pin of the steering joint is further arranged rotate about a third steering axis which is orthogonal to the first and second steering axes to provide a third degree of freedom of motion.

17. The motor vehicle according to any one of claims 14-16 wherein the knuckle hub

includes two diametrically opposed first arms and a third arm perpendicular to each of the two diametrically opposed first arms, wherein one of each of the first joints is mounted in a respective first arm; the steering joint is mounted in the third arm.

18. The motor vehicle according to claim 17 wherein each steering joint includes a bearing received with the third arm and a bush rotatable seated in the bearing, and wherein the first pin of the steering joint is pivotally mounted in the bush about the first steering axis.

19. The motor vehicle according to any one of claims 7-18 comprising one or more

sensors arranged to determine when the vehicle is turning or entering a corner and to generate the one or more input signals for the actuator.

20. The motor vehicle according to claim 19 wherein the sensors comprise one, or any two or more combination of (a) an accelerometer; (b) a gyroscopic sensor; (c) a magnetic sensor and (d) an inertial measurement unit.

21 . The motor vehicle according to any one of claims 19 or 20 wherein the actuator is caused to automatically tilt the wheels to a predetermined tilt angle based on signals received from the sensors.

22. The motor vehicle according to any one of claims 19-21 wherein the sensors are

arranged to determine when the vehicle is not turning or exiting the corner to generate a signal causing the actuator to automatically tilt the wheels about their centre points toward the vertical plane and increase clearance between the chassis and a surface on which the vehicle is travelling.

23. The motor vehicle according to any one of claims 1 -22 comprising a third and fourth wheel and wherein the coupling system is arranged to tilt the third and fourth wheels simultaneously with and in the same direction as the first and second wheels.

24. An articulated mechanical joint facilitating coupling between a first component and a second component the articulated mechanical joint comprising:

a split bush having two or more parts, first and second ones of the parts being provided with recesses two, the spilt bush having an assembled state arranged to engage the first component;

a first pin provided with aligned an opposite arm and an intermediate body having a through hole, wherein the arms locate in the recesses in the first and second parts;

a second pin which passes through the hole and arranged for connection with the second component;

wherein the articulated joint provides a first degree of freedom of motion between the first and second components about a first axis coincident with a longitudinal axis of the first pin, and a second degree of freedom of motion between the first and second components about a second axis coincident with a longitudinal axis of the second pin.

25. The articulated mechanical joint according to claim 24 wherein the split bush when in an assembled state has an inner circumferential surface of increased at a diameter in the axial direction away from the first axis.

26. The articulated mechanical joint according to claim 24 or 25 wherein the split bush is fixedly engaged with the first component.

27. The articulated mechanical joint according to any one of claims 24 - 26 comprising a bearing coupled with the split bush and arranged to enable the split bush to rotate about a central axis of the bearing to provide a third degree of freedom of motion between the first and second components.

Description:
A MOTOR VEHICLE WITH TILTING WHEELS

TECHNICAL FIELD

A motor vehicle is disclosed with tilting wheels. The tilting wheels are also capable of being steered. The vehicle has two wheels with respective centres that lie on a common axis which runs transverse to a direction of travel of the vehicle.

BACKGROUND ART

In a conventional four wheeled vehicle during cornering the weight of the vehicle is transferred to the two outer wheels leaving the inner wheels with limited weight for traction and therefore limiting the cornering ability of the vehicle. This can be offset by using aerodynamic wind drag to force the vehicle to the ground to increase traction on all the wheels. This in turn increases the vehicle’s wind co-efficient which uses substantial power when the vehicle is driving in a straight line. Also, the cornering in extreme cases can result in the inner wheels lifting from the ground, not only loosing traction but also resulting in the centre of gravity of the vehicle shifting toward the outer radius of the turn which increases the risk of the vehicle rolling over.

SUMMARY OF THE DISCLOSURE

In a first aspect there is disclosed motor vehicle comprising:

a chassis having a longitudinal centre line and a vehicle vertical plane through which the longitudinal centre line passes;

first and second wheels on respective opposite sides of the longitudinal centre line; and a coupling system that couples the first and second wheels to the chassis, the coupling system arranged to enable the respective wheel to: tilt in unison relative to the vehicle vertical plane; and, turn in unison with the respective wheel planes remaining parallel with each other.

The effect of the tiling wheels is to move the centre of gravity of the vehicle when the vehicle is cornering to provide increased stability and maintain traction of all the wheels with the surface. The centre of gravity is both lowered and shifted toward the centre of curvature of the corner. In one embodiment the coupling system includes a respective knuckle hub for each of the first and second wheels, wherein each wheel is rotatably coupled to a corresponding knuckle hub; each knuckle hub having respective first joints at each of two diametrically locations opposite a centre point of a corresponding wheel coupling the knuckle hub to the chassis.

In one embodiment the first joint includes a first pin capable of pivoting about a first pivot axis and a second pin pivotally coupled to the first pin about a second pivot axis orthogonal to the first pivot axis and wherein the second pin is coupled to the chassis.

In one embodiment the coupling system includes for each wheel an upper structure and a lower structure, each structure coupled at one end to the chassis and at an opposite end to a respective first pin by an associated second pin about the second pivot axis.

In one embodiment the one end of each structure is coupled to the chassis about a structure pivot axis that lies parallel to the longitudinal centre line.

In one embodiment the coupling system includes a tilt system operable to tilt the first and second wheels relative to the vehicle vertical plane, the tilt system arranged to move the upper and lower structures laterally of the longitudinal centre line.

In one embodiment the tilt system comprises an actuator coupled with the upper and lower structures and arranged to move the upper and lower structures laterally of the longitudinal centreline in response to one or more input signals.

In one embodiment the tilt system comprises a control shaft extending along with the longitudinal centreline and coupled to the upper and lower structures and wherein the actuator is operable to rotate the control shaft about an axis parallel to the longitudinal centreline.

In one embodiment the tilt system comprises at least one linkage member fixed to the control shaft and pivotally coupled at opposite ends to the upper and lower structures.

In one embodiment the tilt system comprises two linkage members each fixed to the control shaft at location spaced along the longitudinal centre line.

In one embodiment the upper and lower structures each comprise a respective wishbone, and wherein each wishbone is connected at one end to both of the linkage members. In one embodiment the tilt system comprises an actuator coupled to the control shaft, wherein the actuator is arranged to rotate the control shaft about an axis parallel to the longitudinal centre line in response to input signals received from sensors on the vehicle, a driver of the vehicle, or both sensors and the driver.

In one embodiment the motor vehicle comprises a steering mechanism coupled with the first and second wheels and capable of steering the first and second wheels independent of an angle of tilt of the wheels.

In one embodiment the knuckle hub includes for each of the first and second wheels, a respective steering joint coupled with the steering mechanism and arranged to provide three degrees of freedom of motion between a steering mechanism and the knuckle hub.

In one embodiment each steering joint comprises a first pin capable of pivoting about a first steering axis to provide a first degree of freedom of motion; and, coupled to the steering mechanism about a second steering pivot axis orthogonal to the first steering axis to provide a second degree of freedom of motion.

In one embodiment the first pin of the steering joint is further arranged rotate about a third steering axis which is orthogonal to the first and second steering axes to provide a third degree of freedom of motion.

In one embodiment the knuckle hub includes two diametrically opposed first arms and a third arm perpendicular to each of the two diametrically opposed first arms, wherein one of each of the first joints is mounted in a respective first arm; the steering joint is mounted in the third arm.

In one embodiment each steering joint includes a bearing received with the third arm and a bush rotatable seated in the bearing, and wherein the first pin of the steering joint is pivotally mounted in the bush about the first steering axis.

In one embodiment the motor vehicle comprises one or more sensors arranged to determine when the vehicle is turning or entering a corner and to generate the one or more input signals for the actuator. In one embodiment the sensors comprise one, or any two or more combination of (a) an accelerometer; (b) a gyroscopic sensor; (c) a magnetic sensor and (d) an inertial measurement unit.

In one embodiment the actuator is caused to automatically tilt the wheels to a predetermined tilt angle based on a feedback signal received from the sensors.

In one embodiment the sensors are arranged to determine when the vehicle is not turning or exiting the corner to generate a signal causing the actuator to automatically tilt the wheels about their centre points toward the vertical plane and increase clearance between the chassis and a surface on which the vehicle is travelling.

In one embodiment the motor vehicle comprises a third and fourth wheel and wherein the coupling system is arranged to tilt the third and fourth wheels simultaneously with and in the same direction as the first and second wheels.

In a second aspect there is disclosed a motor vehicle comprising:

at least a first wheel and a second wheel;

a control shaft extending along a longitudinal centreline of the vehicle; and

a coupling system coupling the first and second wheels to, and on opposite sides of, the control shaft;

wherein the control shaft is operatively associated with a first coupling system so that rotation of the control shaft about the longitudinal centre lines causes both the first and second wheels to tilt in unison in the same direction from a vertical plane and reduce clearance between the control shaft and a surface on which the vehicle rides.

In an embodiment of the second aspect the coupling system includes a respective knuckle hub for each of the first and second wheels, each knuckle hub rotatably coupled with a corresponding wheel and the control shaft, each knuckle hub connected at respective first joints at each of two locations diametrically opposite about a centre point of the wheel.

In an embodiment of the second aspect each first joint includes a first pin capable of pivoting about a first tilting axis; and, coupled to the control shaft about a second tilting axis orthogonal to the first axis. In an embodiment of the second aspect the coupling system includes for each wheel an upper wishbone and a lower wishbone, each wishbone coupled at one end to the control shaft and at an opposite end to a respective first pin about the second tilt axis of that pin.

In an embodiment of the second aspect the vehicle comprises a steering mechanism coupled with the first and second wheels and capable of steering the first and second wheels independent of rotation of the control shaft.

In an embodiment of the second aspect the knuckle hub includes for each of the first and second wheels, a second joint coupled with the steering mechanism and arranged to provide pivotal motion about each of three orthogonal axes.

In an embodiment of the second aspect each second joint comprises a second pin capable of pivoting about a first steering axis; and, coupled to the steering mechanism about a second steering pivot axis orthogonal to the first steering axis.

In an embodiment of the second aspect the second pin is further arranged rotate about a third steering axis which is orthogonal to the first and second steering axes.

In an embodiment of the second aspect the knuckle hub includes two diametrically opposed first arms and a third arm perpendicular to each of the two diametrically opposed first arms, wherein the two first arms are coupled to the control shaft.

In an embodiment of the second aspect the first joints are mounted in the two arms, one first joint in each of the two arms.

In an embodiment of the second aspect the second joint associated with a wheel is mounted in the third arm of a corresponding knuckle hub.

In an embodiment of the second aspect each second joint includes a bearing received with the third arm and a bush rotatable seated in the bearing, and wherein the third pin is pivotally mounted in the bushing about the first steering axis.

In an embodiment of the second aspect the vehicle comprises one or more sensors arranged to determine when the vehicle is turning or entering a corner and generate a signal causing the control shaft to automatically rotate in a first direction to cause the wheels to tilt about their centre points into the corner and the reduction in clearance between the control shaft and the surface.

In an embodiment of the second aspect the one or more sensors comprise three X-axis sensors.

In an embodiment of the second aspect the control shaft is caused to automatically rotate to a predetermined angle based on a feedback received from the sensors.

In an embodiment of the second aspect the sensors are arranged to determine when the vehicle is not turning or exiting the corner and to generate a signal causing the control shaft to automatically rotate in second direction in a manner to cause the wheels to tilt about their centre points toward the vertical plane and increase clearance between the control shaft and the surface.

In an embodiment of the first or second aspect the vehicle comprises a driver controlled wheel tilt system coupled with the wheels and arranged to enable the driver to control or otherwise adjust a tilt angle of the wheels.

In an embodiment of the first or second aspect the driver controlled wheel tilt system includes actuators on a steering wheel or steering column of the vehicle.

In an embodiment of the first or second aspect the actuators comprise one or more, or a combination, of: a lever; a button; a dial; and a switch.

In an embodiment of the first or second aspect the actuators control a mechanical, hydraulic or electrical system for controlling or otherwise adjusting the tilt angle of the wheels.

In one embodiment of the second aspect the control shaft and the first control system are configured to affect a shift in a centre of mass of the vehicle when entering a corner toward an inner radius of the corner.

In one embodiment of the second aspect the vehicle comprises a third and fourth wheel and a second coupling system coupling the third and fourth wheels to, and on opposite sides of the control shaft, wherein each wheel has a centre point about which that wheel can pivot; wherein the control shaft is operatively associated with the third and fourth wheels so that rotation of the control shaft about the longitudinal centre lines causes both the third and fourth wheels to pivot in unison in the same direction from a vertical plane.

In a third aspect there is disclosed an articulated mechanical joint facilitating coupling between a first component and a second component the articulated mechanical joint comprising:

a split bush having two or more parts, first and second ones of the parts being provided with recesses, the spilt bush having an assembled state arranged to engage the first component; a first pin provided with aligned an opposite arm and an intermediate body having a through hole, wherein the arms locate in the recesses in the first and second parts; and

a second pin which passes through the hole and arranged for connection with the second component;

wherein the articulated joint provides a first degree of freedom of motion between the first and second components about a first axis coincident with a longitudinal axis of the first pin, and a second degree of freedom of motion between the first and second components about a second axis coincident with a longitudinal axis of the second pin.

BRIEF DESCRIPTION OF THE DRAWINGS

Notwithstanding any other forms which may fall within the scope of the vehicle as set forth in the summary, specific embodiments will now be described by way of example only with reference to the accompanying drawings in which:

Figure 1 is a schematic representation in plan view of an embodiment of the disclosed motor vehicle when all four wheels are tilted at about 45° and the front wheels are at a steering angle of 45°.

Figure 2 is a schematic representation of a front part of the disclosed vehicle showing a control shaft, front wheels, a coupling system that couples the front wheels to the control shaft; the front suspension; and, steering mechanism. The wheels are shown tilted by about 45° and at a steering angle of about 45°.

Figure 3 is an exploded view of the front part of the vehicle shown in Figures 1 and 2 with the front wheels in a vertical plane and a steering angle of 0°. Figure 4a is an exploded view of a knuckle hub assembly and associated first and second joints incorporated in the vehicle which facilitate the tilting and steering of the front wheels.

Figure 4b is a view of detail A from Fig 4a of a first joint which is incorporated in the knuckle hub assembly and connected to a wishbone of the coupling system.

Figure 4c is a view of detail B from Fig 4a of a front wheel rotary steering joint which is incorporated in the knuckle hub assembly and connected to a steering arm rod.

Figure 5a is a plan view of the front part of the vehicle shown in Figures 2 and 3 with the front wheels in a vertical plane and a steering angle of 0°.

Figure 5b is view of section AA of Figure 5a.

Figure 5c is a section view of detail B of a front wheel of Figure 5b.

Figure 5d is a section view of detail C of the Figure 5c showing a first joint connecting a wishbone of the vehicle to the knuckle hub.

Figure 6 is an exploded view of a rear assembly of the vehicle shown in Figure 1 but with all the wheels in a vertical plane (i.e. not tilted) and the front wheels at a 0°steering angle (i.e. the vehicle travelling in a straight line).

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

With reference to Figures 1 - 3 an embodiment of the disclosed motor vehicle 10 comprises a first wheel 12R and a second wheel 12L, being the front right wheel and the front left wheels respectively (and herein after referred to in general as“front wheels” 12) of the vehicle 10. The vehicle 10 also includes a control mechanism which in this embodiment is in the form of a shaft 14 that extends along a longitudinal centre line 16 of the vehicle 10. The vehicle also includes a vehicle vertical plane through which the longitudinal centre line passes. A first coupling system 18 couples the front wheels 12 to, and on opposite sides of, the control shaft 14. The control shaft 14 is operatively associated with the first coupling system 18 so that rotation of the control shaft about the longitudinal centre line 16 causes both the front wheels 12 to pivot or tilt in unison in the same direction. Each wheel has a respective radial plane, being a plane that contains the geometric radius of that wheel. When the vehicle is travelling in a straight line the wheel and thus its radial plane is vertical. In embodiments of the present vehicle 10 and coupling system 18, when the vehicle 10 is cornering the radial planes of the wheels stay parallel to each other and tilt in the same direction. As explained later the control shaft 14 may also be arranged to cause tilting of the rear wheels. This results in the wheels 12, and/or their wheel planes being angled from the vehicle vertical plane. The tilting of the wheels also has the effect of reducing clearance between the control shaft 14 and the surface on which the vehicle travels or is supported. In addition, the tilting of the front and rear wheels 12 results in a shifting of the centre of gravity of a vehicle 10 in a direction of tilting of the wheels 12.

Looking more closely at Figure 3 the first coupling system 18 includes, for each front wheel 12, an assembly of components including but not limited to: a knuckle hub assembly 19 having a knuckle hub 20; an upper structure 22U; and a lower structure 22L. In this embodiment the structures 22U and 22L are in the general form and configuration of a wishbone structure and for ease of reference are hereinafter referred to in general as “wishbones 22”. As shown in relation to the wheel 12L on Fig 3, each knuckle hub assembly 19 includes a knuckle hub 20 and two first (or tilting) joints 24U and 24L (hereinafter referred to in general as“first joints 24”). The first joints 24 are at diametrically opposed locations about a centre point 26 of the corresponding wheel 12. The coupling system 18 operates at the centre axis AA (shown in Fig 5a) of wheels 12 in all directions.

Each knuckle hub assembly 19 is also formed with a second joint 28, which may also be referred to as a steering joint 28, fitted a corresponding knuckle hub 20. The steering joint 28 is located between the two first joints 24 and radially offset from the centre point 26. The steering joint 28 is also able to pivot in all directions like joints 24 but in addition, and as explained in greater detail below, it is also able to rotate as needed to maintain a connection to the knuckle hub assembly during tilting and leaning. The first joints 24 and the second or steering joint 28 are articulated joints.

The lower left-hand side of Figure 3 shows an exploded view of the knuckle hub 20. The knuckle hub 20 has two diametrically opposed first arms 30U and 30L (hereinafter referred to in general as“first arms 30”) and a third arm 32 perpendicular to each of the first arms 30. A circular seat 33 is formed at the end of each of the arms 30 and 32. The seats are provided with circumferential lips 35 at one axial end. A fourth arm 34 extends opposite the third arm and perpendicular to the first arms 30. Each of the arms 30, 32 and 34 radiate from a central boss 36. The arms 30, 32, and 34 lie in the same plane. The first joints 24U and 24L are mounted on or to the first arms 30U and 30L respectively. With reference to Figures 3 and 4 each first joint 24 has a first pin 38 that is capable of pivoting about a first pivot axis 40. The axis 40 is in a vertical plane when the wheels 12 are in a vertical plane. The first pin 38 is coupled to the control shaft 14 about a second pivot axis 42 which is orthogonal to the first pivot axis 40. This coupling is via the coupling system 18. More particularly the coupling between the first pin 38 and the control shaft 14 is via the upper wish bone 22U. The pin 38 is retained within a split bush 44. The spilt bush 44 has two halves 45 which locate together by way of locating pins 47 on one half and

corresponding holes (not shown) in the other half. Optionally the halves may be magnetised to attach to each other when mutually adjacent with the locating pins 47 in their respective holes. The split bush 44 is formed with diametrically opposed circular recesses 46 which receive opposite ends 48 of the pin 38; together with bearings 50 and thrust bearings and shims 52. The thrust bearings and shims 52 are first placed in the recesses 46 followed by the bearings 50. The ends 48 fit within the bearings 50. The recesses 46 are formed in small protrusions 53 formed on the inner circumferential surface 59 of the bushes 44. The pin 38 of the first joint 24 has a central annular body 54 provided with a central hole 56. The hole 56 receives a pivot pin 58 that is used for pivotally connecting the first joint 24 to the upper wishbone 22U about the axis 42. A bearing sleeve 60 is fitted in the hole 56 and forms a bearing surface for the pin 58. Thus, the pin 58 is pivotally connected to the pin 38 about the axis 42.

The axes 40 and 42 which coincide with the axes of the pins 38 and 58 provide first and second degrees of freedom of motion between the components coupled by the joints 24, namely the knuckle hub 20 and the wishbones 22. A first the degrees of freedom of motion being a pivoting or rotational motion about the axis 40, and a second of the degrees of freedom of motion being a pivoting or rotational motion about the axis 58. The degree of pivotal motion about axis 40 can be maximised or controlled by bevelling an inner circumferential surface 59 of the bush 44 so that the inner diameter of the surface 59 increases in an axial direction away from the axis 40. Stated another way the thickness of the bush 44 at the surface 59 increases from a minimum to a maximum along a radius from the centre to the outer edge of the bush 44. This is most apparent from Figure 4b by the diagonal edge 61 at the joining face of the bush part 45.

In one example the surface 59 can be bevelled so that when a yoke is connected with the pin 58, the body 54 and pin 38 can pivot about the axis 40 by up to about ±62° within the bush. The upper wishbone 22U has one end 60 formed with connecting yoke having a pair of spaced apart eyes 64. In an initial stage in the assembly of the coupling system 18 the wishbone 22U is connected to the pin 38 by locating the body 54 between the eyes 64 and then inserting the pin 58 through the eyes 64 and hole 56. The pin 58 is held in place by circlips 66 that engage with the ends of the pin 58 on the outside of the eyes 64. With the end 62 of the wishbone 22U coupled to the pin 38 the remainder of the first joint 24 can be assembled and then inserted into the seat 33 of arm 30U. The first joint 24 is prevented from falling out of one end of the seat 33 by abutment with the lip 35. The joint 24 is then held in the seat 33 by a circlip 74 which sits in behind the bush 44 and inside of a second lip 37 formed in an axial end of the seat 33 opposite the lip 35. The lip 37 has a diameter sufficient to pass the bush 44. A washer 72 is then laid over the circlip 74 and that end of the seat 33 is closed by a plate 68 which is attached to the bush 44 by screws 70.

The lower first joint 24L is of identical construction to the first joint 24U and is coupled to the seat 33 on the arm 30L.

The bushes 44 are fixed within the respective arms 33 in an orientation where the recesses 46 are aligned with the axis of the arms 30. Irrespective of the degree of tilt of the wheels 12 or the steering angle of the wheels 12, the pivot axes 40 of the pins 38 and the centre point 26 of the corresponding wheel always remain along a common straight line; and

consequentially in the same plane.

The second joint 28 is of similar construction to the first joint 24 and in particular includes a pin 78 that may differ from the pin 38 by having an annular body 80 of a greater outer diameter than the body 54 and a central hole 82 of greater inner diameter than hole 56. The second joint 28 includes: circular arms 84 in line with each other and extending form opposite location on the body 80; bearing sleeves 86 which receive the respective arms 84 and are themselves held within circular recesses 88 of an associated split bush 90; and, a bearing sleeve 92 that is located within the hole 82 and through which a pivot pin 94 extends. Circlips 96 are provided for retaining the pin 94 within the hole 88. As described later the pin 94 is connected with a steering mechanism.

The split bush 90 of the second joint 28 differs from the bush 44 by the provision, on its outer circumferential surface, of a central circumferential flange 98 and opposed bearing seats 100. Respective bearing 102 are seated on each of the seats 100. The spilt bush 90 has two halves 91 which locate together by way of locating pins 93 on one half and corresponding holes (not shown) in the other half. Optionally the halves may be magnetised to attach each other when the locating pins 93 are in their respective holes.

When the second joint 28 is fully assembled and installed in the seat 33 at the end of arm 32 the bearings 102 allow the bush 90 to rotate a full 360° about an axis 104 of the seat 33.

This coincides with the central axis of the bearings 102 and the bush 90. The pin 78 can pivot about a longitudinal axis 106 which is orthogonal to the axis 104. The pin 94 can pivot or rotate about an axis 108 which is orthogonal to both axis 104 and 106. The axis 108 coincides with the axis of the hole 82. The rotation of the bushes 90 is provided to facilitate the steering when the wheels 12 are tilted.

The second joint 28 is retained in the seat 33 in an identical manner to the first joints 24 namely by way lip 35 which stops the bush 90 from falling out of one end of the seat 33 in the arm 32; a circlip 1 12 that sits behind the bush 90 and retained by the lip 37 at an opposite end of the seat 33. A washer 1 14 is placed over the circlip 1 12 and finally a plate 109 is attached by screws 1 10 onto the bush 90. The plate 109 has a diameter same as the diameter of the seat 33.

From the above description it should be apparent that the second joint 28 gives three degrees of freedom between the component parts coupled by the joint 28, these being the knuckle hub 20 and a steering mechanism 150 which is described in greater detail below. The three degrees of freedom are as follows: (a) pivotal or rotational motion about the axis 106 of about ±62° perpendicular to the pin 78; (b) pivotal or rotational motion about the axis

108 of about ± 47° when a rod such a steering rod 158 is in the same plane as the pin 78; and (c) full 360° rotational motion of the bush 90 about the axis 104.

The degree of pivotal motion about axis 106 can be maximised or controlled by bevelling the inner circumferential surface 107 of the bush 90 so that the inner diameter of the surface increases in an axial direction away from the axis 106. That is, the thickness of the bush 90 at the surface 107 increases from a minimum to a maximum along a radius from the centre to the outer edge of the bush 90. This is most apparent from Figure 4c by the diagonal edge

109 at the joining face of the bush part 91. As with the bush 44, the bush 90 is also formed with respective protrusions 1 1 1 from which the recesses 86 stem. The protrusions 1 1 1 limit the maximum angle of inclination of a rod (such as a steering rod 158) about the axis 108 when the rod lies in the same plane as the pin 78. The knuckle hub 20 is formed with two diagonally extending members 1 16 on opposite sides of the arm 34. The arm 34 together with the members 1 16 are used for attaching brake callipers 1 18. The brake callipers 1 18 are part of a disc braking system which includes a rotor 120 which is fixed to a corresponding wheel 12.

The knuckle hub 20 is rotatably coupled to a rim 122 of a wheel 12 via a wheel hub 124.

The wheel hub 124 has a spindle bearing 126 on one side on which the boss 36 of the knuckle hub 20 is mounted. The hub 124 also includes a mounting flange 128 and a front wheel spindle 130. A lock nut 132 can be screwed on to and off the wheel spindle 130. The wheel hub 124 is fixed to the rim 122 by way of studs 134 on the flange 128, and the lock nut 132. Thus, the rim 122, wheel 12 and the wheel hub 124 rotate together when the vehicle 10 is in motion relative to the knuckle hub 20 which remains stationary.

Each of the wishbones 22 is in the general form of a triangular frame having two side members 136 which join at the end 62 but are spread apart at an opposite end 138. Each of the members 136 at their ends 138 is formed with a mounting boss 140 having a central hole 142. Several cross members 144 extend between and join the side members 136 together.

The ends 138 of the wishbones 22 are pivotally coupled at least one (in this instance two) tilt control linkage members 146 which are fixed to the control shaft 14. Each linkage member 146 has opposed arms 148U and 148L (see Fig 2). The ends 138 of the upper wishbones 22U on both the left and right-hand side of the vehicle 10 are pivotally connected to the upper arms 148U of both linkages 146. Similarly, the ends 138 of the lower wishbones 22L on both the left and right-hand side of the vehicle 10 are pivotally connected to the lower arms 148L of each of the linkages 146. The pivot coupling of the wishbones 22 to the linkage members 146 enables the ends 138 of the wishbones 22 to pivot about axes 149 that are parallel to the central axis 16 as shown in Figure 2. In turn this allows the wishbones 22 to be moved laterally toward or away from the axis 16. The axes 16 and 149 all live in a common plane. When the vehicle 10 is moving in a straight line this common plane is vertical. The ability of the wheels 12 to tilt for example when the vehicle 10 is traversing a corner is in part due to the ability to tilt the common plane about the axis 16.

Referring to Figures 2 and 3 the vehicle 10 includes a steering mechanism 150 for steering the wheels 12. The steering mechanism 150 includes a steering box 152 with a shaft 154 that can translate relative to an outer housing of the steering box 152. The steering box 152 can take many different forms such as a mechanical steering box, hydraulic or electrical. A right-hand end of the shaft 154 is coupled to a right steering rod 158R while the left-hand side of the shaft 154 is connected to a left steering rod 158L. Distant ends of the steering rods 158R and 158L (hereinafter referred to in general as“steering rods 158”) are provided with a connecting yoke having spaced apart fixing eyes 160. The steering rods 158 are pivotally connected to corresponding second (steering) joints 28 by way of the pivot pin 94 which passes through the eyes 160 and the central hole 82 of the pins 78. The pivot pins 94 are kept in place by the circlips 96. During tilting of the wheels 12, the steering rods 158 stay about the centre axis of the vehicle and are not affected by the tilting of the wheels.

The vehicle 10 includes a suspension system 162 that is interlinked with the coupling system 18. With reference to Figures 3 and 5 the suspension system 162 includes: a pair of coil spring and damper assemblies 164, corresponding push rod rocker arms 166, suspension push rods 168, tie rods 170 and a sway bar 172. During tilting of the wheels 12, the tie rods 170 remain about the centre axis of the vehicle and are not affected by the tilting of the wheels 12. One end 174 of each of the coil spring and damper assemblies 164 is fixed to a chassis of the vehicle 10. An opposite end of the assemblies 164 is pivotally attached to one end of a corresponding rocker arm 166. Each rocker arm 166 is in turn pivotally attached to a corresponding suspension push rod 168. Each push rod 168 is pivotally coupled to a corresponding tie rod 170 at a mid length location. Opposite ends of the tie rod 170 are pivotally attached to the upper and lower wishbone arms 22U and 22L on respective sides of the vehicle 10.

Looking at Figure 3 each of the wishbones 22 is formed with a yoke 175 near its end 62. Respective ends of the tie rods 170 are formed with a boss 176 at either end. The bosses on either side of the vehicle 10 fit within the yokes 175 of the upper and lower wishbones 22 on the same side. A pin 178 passes through the yoke 175 and collects the boss 176 to pivotally connect ends of the tie rods 170 to the wishbones 22. A bracket 180 attaches opposite ends of the sway bar 172 to the push rods 168 and the tie rods 170.

When the coupling system 18 is in a neutral position which corresponds to the vehicle 10 travelling in a straight line, the wheels 12 and the linkage members 146 lie in respective vertical planes. When the control shaft 14 is rotated in a clockwise or anticlockwise direction about the longitudinal centre line 16 the linkage members 146 are rotated to the same extent and have the effect of moving the wishbones 22 laterally toward or away from the axis 16 to cause tilting of the wheels 12 about their centre points 26. The tilting of the wheels 12 is controlled an actuator 182 (Fig 6) that is attached to the control shaft 14. A PLC or other processor (not shown) controls the operation of the actuator 182 by processing signals from connected sensors (not shown). The sensors typically include a plurality of accelerometers that provide input signals to the PLC which in turn is programmed to determine whether or not the vehicle 10 is turning. The sensors may also include one or more gyroscopes, magnetic sensors, or inertial measurement units. Based on readings or signals from the sensors that may include sensed G force on, and speed of, the vehicle 10, the PLC, running a dedicated algorithm, commands the actuator 182 to rotate a predetermined amount to provide the optimum tilt angle for the wheels 12 for traversing a bend or corner. The tilt angle may be variable up to about 45°. The tilt angle is maintained until the sensors sense that the vehicle is coming out of the bend or corner in which case the PLC will then command the actuator 182 to rotate the control shaft 14 to return the wheels 12 to a more vertical position.

Additionally, the sensors may be arranged to determine when the vehicle is not turning or exiting the corner to generate a signal causing the actuator 182 to automatically tilt the wheels about their centre points toward the vertical plane. This will also bring about an increase in the clearance between the chassis and a surface on which the vehicle is travelling.

The combination of the linkage members 146, control shaft 14 and the actuator 182 may be considered as forming a tilt system of the vehicle 10, which is a subsystem of the coupling system 18. The tilt system operates to tilt the wheels 12 relative to the vehicle vertical plane. To do this to tilt system is arranged to move the upper and lower structures/wishbones 22 laterally of the longitudinal centre line 16.

Figure 2 shows the wheels 12 tilted by about 45°. This tilting is possible by virtue of the first joints 24 that provide a pivot connection between the knuckle hub 20 and the wishbones 22. More particularly the tilting is possible because the pin 38 can pivot about the axis 42 within its corresponding bush 44 and the wishbones 22 can pivot about axes 149. Steering of the titled wheels 12 is possible by the steering mechanism 150 and the corresponding second joints 28 that allow rotation of the corresponding bushes 90 within their respective seats 33 about axis 104, as well as pivoting of the pins 78 about axis 106 within their bushes 90 and the pivoting connection of the steering rods 158 about axes 108 on the pins 94 that pass through the pins 78.

In this, but not necessarily all embodiments, the vehicle 10 is provided with tilting rear wheels 188. The wheels 188 are part of an integrated motor and wheel assembly 190 which includes an engine 192 and suspension 194. With reference to Figure 6 the assemblies 190 are coupled to the control shaft 14 by a link arm 196 and push rods 198. The push rods 198 and link arm 196 together form a rear wheel coupling system 200 that has the effect of tilting the rear wheels 188 in the same tilting direction to the front wheels 12. The rear wheel coupling system 200 may be considered as a subsystem of the coupling system 18. The link arm 196 is fixed to the control shaft 14 while respective push rods 198 are pivotally coupled at one end to the link arm 196 and at their opposite ends to respective wheel assemblies 190. The tilting of the rear wheels 188 is also done about their respective vertical and horizontal centre points.

The vehicle 10 has a chassis 201 to which the control shaft 14, coupling system 18, suspension system 162 and rear wheel assemblies 190 are connected. The chassis also supports seats 202 for a driver and a passenger. In this embodiment the seats 202 are also coupled with the control shaft 14 by a link 204 and push rods 206 (see Figure 6) to cause the seats 202 to tilt in the same direction as the wheels 12.

When the rear wheels 188 and/or the seats 202 are arranged to be tilted in conjunction with the front wheels 12, the above described tilt system also includes the link arm 196, push rods 198, the coupling system 200, link 204, push rods 206; and associated coupling to the control shaft 14.

In summary, the coupling system 18 that couples the first and second wheels 12L, 12R to the chassis 201 , enables the respective wheel to: tilt in unison relative to the vehicle vertical plane; and, turn in unison with the respective wheel planes remaining parallel with each other. The coupling system 18 enables the tilting and steering of the wheels to occur independently of each other but also simultaneously together. Thus, the wheels 12 can be tilted without being steered by the steering mechanism, or steered by the steering mechanism but not tilted, or both steered and tilted at the same time. The tilting of the wheels automatically causes a lowering of the chassis 201 towards the surface on which the vehicle 10 is driving. In broad terms the coupling system 16 is the combination of the knuckle hub assemblies 19, the upper and lower structures (in this embodiment, the structures being the wishbones) 22 and the tilt system.

When the vehicle 10 is cornering the front wheels 12 and rear wheels 188 tilt by virtue of their coupling to the control shaft 14 which rotates about the longitudinal centre line 16 which in turn causes translation of the wishbones 22 (for the front wheels 12) and the link arms 196 (for the rear wheels). The tilting of the wheels reduces the clearance between the chassis 201 and therefore the control shaft 14 and the surface on which the vehicle is travelling. This lowers the centre of gravity of the vehicle 10 when cornering. Also, the centre of gravity is moved toward the centre of curvature of the corner. The nett effect of this shift in the centre of gravity (which can be equated with a movement in the mass of the vehicle) is to increase stability and to keep traction of all wheels on a road surface. Consequently, the need for aerodynamic devices to provide traction during cornering and that result in increased drag is reduced or obviated. The tilting of the wheels induces cornering and reduces the need to steer the vehicle 10 around a corner the vehicle, this reducing understeer which is prevalent when cornering in a conventional (non-tilting wheel) vehicle.

Whilst a specific embodiment is described above other embodiments or enhancements are possible. For example, the motor vehicle may also include a driver controlled wheel tilt system coupled with the wheels and arranged to enable the driver to control or otherwise adjust a tilt angle of the wheels. This may operate either as an alternative to the PLC so only the driver input causes the control shaft 14 to rotate, or, in addition to the PLC to enable the vehicle driver/operator to adjust the degree of tilt of the wheels provided by the PLC and sensors. In such an embodiment the driver controlled wheel tilt system may include actuators on a steering wheel or steering column of the vehicle. The actuators may comprise one or more, or a combination, of: a lever; a button; a dial; and a switch. The actuators may in turn control or operate a mechanical, hydraulic or electrical system for controlling or otherwise adjusting the degree of rotation of the shaft 14 and thus the tilt angle of the wheels.

Also, the tilt system may have an alternate structures and mechanisms for applying force to tilt the wheels 12 and 188 (when they are coupled in a manner to allow tilting). For example, instead of the control shaft 14 is rotated by the actuator 182; the tilting system could comprise a control mechanism in the form of a plurality of linear actuators which are pivotally connected between the linkages 146 and the chassis 201 to extend or retract thereby pivoting the linkages 146 about the longitudinal centre line 14. The linear actuators would receive inputs from either sensors on the vehicle and/or user operable controls such as a steering wheel, levers or buttons.

In the claims which follow and in the preceding description, except where the context requires otherwise due to express language or necessary implication, the word“comprise” and variations such as“comprises” or“comprising” are used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features of the container as disclosed herein.