Vehicle suspension system providing continuous vertical orientation of the ground wheel

A vehicle suspension system includes a modified wheel structure including an outer rim rotating upon an inner member formed substantially as a hollow cylindrical drum on an outer surface of which the rim is mounted on bearings provided between the outer surface and the inner surface of the rim. A suspension arm from the vehicle frame projects from the vehicle frame into the hollow drum for pivotal movement of the wheel relative to the suspension arm about a horizontal axis which lies substantially in the vertical central plane of the wheel. In a steering system, the suspension arm connects with a cap mounted on a post at the bottom of the inner member with a hydraulic motor driving rotation of the inner member relative to the cap for a steering action. The drive system to the wheel is transmitted through an open inner face of the drum through a hole in an outer face of the drum to a drive disc mounted on the outer face and communicating radially outwardly to the outwardly facing edge of the rim member. The suspension system does not require any cantilever effect and allows a central plane of the wheel to remain vertical at all times.

BACKGROUND OF THE INVENTION 
This invention relates to a vehicle suspension system designed to provide 
continuous vertical orientation of the central plane of the ground wheel 
while the suspension allows the wheel to move vertically relative to the 
frame of the vehicle. 
Conventional suspension systems particularly for the front wheels of a road 
vehicle generally provide a suspension arm pivotally mounted on a suitable 
frame member at a position inwardly of the wheel towards a centre line of 
the vehicle. At an outer end of the pivot arm is provided a wheel support 
or coupling member with the wheel being carried on a cantilever arm which 
extends outwardly from the coupling member into the hub of the wheel and 
providing a shaft carrying bearings on which the wheel is mounted for 
rotation around the wheel axis. 
In many cases, pivotal movement of the suspension arm causes the wheel axis 
to pivot so that a central plane of the wheel no longer remains vertical 
but twists about an axis longitudinal to the forward movement of the 
vehicle, thus changing the camber angle of the wheel. 
In order to steer the wheel it is generally necessary to provide ball 
joints which allow the cantilevered shaft to pivot about a substantially 
vertical axis positioned inwardly of the wheel toward the centre line of 
the vehicle. This pivot action causes the wheel to move forwardly and 
rearwardly in the steering action and causes significant changes within 
the vehicle geometry as the steering takes place. 
As the movement of the suspension changes the orientation of the central 
plane of the wheel, it also changes the orientation of the periphery of 
the tire relative to the horizontal surface of the ground. The tire 
therefore must deform to maintain as much flat surface of tire on the 
ground as possible while the angle of the rim supporting the tire varies. 
Attention has been given in recent years to reducing the profile of the 
tire but this is limited by the fact that the tire must have sufficient 
ability to deform to accomodate these changes in angle of the rim relative 
to the ground. 
The steering and suspension system in the conventional system is relatively 
complex and must be manufactured using relatively heavy components in view 
of the significant forces involved in the cantilever support arrangement. 
The geometry of the steering suspension system also provides complication 
in the alignment so that careful checking of the alignment is necessary 
and in the event that the alignment is disturbed, this can rapidly lead to 
damage to the tires. 
The conventional steering and suspension geometry has therefore all of the 
above problems and yet remains substantially unaltered after many years of 
development. 
Racing cars often use a somewhat different suspension system which attempts 
more vigorously to retain the periphery of the tire permanently horizontal 
in view of the fact that the traction between the tire and the ground is 
significantly more important during racing. The suspension system 
therefore includes often a parallelogram type linkage so that the wheel 
hub mounted inside the drum type rim stays substantially vertical while 
moving upwardly and downwardly in the suspension action. This system 
however provides a very limited amount of suspension movement which is 
suitable for racing vehicles but is not suitable for conventional road 
vehicles where the roadway is less than perfect and the passengers expect 
more comfort. 
SUMMARY OF THE INVENTION 
It is one object of the present invention, therefore, to provide an 
improved suspension system for a motor vehicle. 
According to a first aspect of the invention, therefore, there is provided 
a vehicle suspension system comprising a vehicle frame member, a ground 
wheel having a peripherally extending ground engaging tire, a wheel rim 
member on which the tire is mounted for rotation about a substantially 
horizontal axis of the wheel and defining a vertical central plane of the 
wheel lying radial to the axis and substantially midway across the width 
of the tire, an inner member, bearing means mounting the rim member on the 
inner member for rotation relative thereto about the wheel axis, a 
suspension arm, means pivotally mounting the arm on the frame member for 
pivotal movement about a horizontal axis allowing vertical movement of the 
ground wheel relative to the frame member, resilient suspension means 
resiliently supporting the arm against vertical movement in an upward 
direction and coupling means coupling an outer end of the arm to the inner 
member, said coupling means holding said inner member against rotation 
around the wheel axis, said coupling means and said inner member defining 
a pivot axis for pivotal movement of the arm relative to the inner member, 
said pivot axis being horizontal and lying in said central plane. 
According to a second aspect of the invention, therefore, there is provided 
a vehicle suspension system comprising a vehicle frame member, a ground 
wheel having a peripherally extending ground engaging tire, a wheel rim 
member on which the tire is mounted for rotation about a substantially 
horizontal axis of the wheel, an inner member, bearing means mounting the 
rim member on the inner member for rotation relative thereto about the 
wheel axis, a suspension arm, means pivotally mounting the arm on the 
frame member for pivotal movement about a horizontal axis allowing 
vertical movement of the ground wheel relative to the frame member, 
resilient suspension means resiliently supporting the arm against vertical 
movement in an upward direction and coupling means coupling an outer end 
of the arm to the inner member, said coupling means holding said inner 
member against rotation around the wheel axis, wherein the inner member 
comprises a substantially cylindrical wall coaxially surrounding the wheel 
axis and located radially inwardly of and supporting the wheel rim, 
bearing means positioned radially outwardly of the cylindrical wall 
between the cylindrical wall and the wheel rim, the cylindrical wall 
surrounding the coupling means, said coupling means and said inner member 
defining a pivot axis for pivotal movement of the arm relative to the 
inner member, said pivot axis being horizontal and lying within said 
cylindrical wall. 
With the foregoing in view, and other advantages as will become apparent to 
those skilled in the art to which this invention relates as this 
specification proceeds, the invention is herein described by reference to 
the accompanying drawings forming a part hereof, which includes a 
description of the best mode known to the applicant and of the preferred 
typical embodiment of the principles of the present invention, in which:

DETAILED DESCRIPTION 
Turning firstly to FIGS. 1, 2 and 3, a vehicle suspension system comprises 
a ground wheel generally indicated at 10 mounted upon a suspension arm 11 
coupled to a vehicle frame member schematically indicated at 12. 
The ground wheel 10 comprises a tire 13 mounted upon a rim member 14 
carried for rotation about a wheel axis upon an inner member 15. 
The inner member 15 comprises a substantially cylindrical ring 16 
surrounding and coaxial with the wheel axis which is coupled to an outer 
end cap member 17 defining an end plate of the cylinder. The inner member 
is thus substantially cylindrical defining a hollow interior and with an 
open inner face 18 through which the suspension and drive systems can 
pass. 
The outer face of the inner member is formed with a central cylindrical 
portion 19 and a pair of frusto conical portions 20 and 21 which increase 
in radial extent from the outer ends of the cylindrical portion towards 
the sides of the wheel. The frusto conical portions act as support 
elements for roller bearings 22 positioned between the outer surface of 
the cylindrical inner member and an inner surface of the rim member 14. 
Thus the rim member 14 is cooperatingly shaped with a central cylindrical 
portion and a pair of outer frusto conical portions tapering to match the 
shape of the outer surface of the inner member and to receive the bearings 
22 therebetween. It will be noted that the outer frusto conical portion 21 
is formed as a portion of the surface of the end plate 17 so that the end 
plate 17 can be removed by disconnecting bolts around the periphery of the 
end plate thus removing the bearings 22 and allowing the rim member 14 to 
slide axially off the outside surface of the inner member for removal of 
the wheel. However with the end cap replaced the wheel is maintained in 
proper position for rotation about the wheel axis and is supported 
effectively by the roller bearings 22 which are under little stress in 
view of the fact that there are relatively large number of the roller 
bearings and that there speed of revolution is significantly less than 
that of bearings positioned adjacent a central axle of a conventional 
wheel arrangement. 
In normal rotation of the wheel about the wheel axle, therefore, the inner 
member remains stationary and the rotating mass is provided simply by the 
rim member 14 and the tire 13 thus reducing the mass of the rotating part 
of the wheel relative to a conventional wheel construction. 
Fixed at the top and bottom respectively of the inner member is a platform 
24 and 25 each of which defines a horizontal surface fixed within the 
inner member and formed integrally with the inner member for controlling 
the position of the inner member and thus the position of the wheel. 
The lower platform 25 carries a post member 26 projecting vertically 
upwardly therefrom in the form of a cylindrical body having a flat upper 
surface 27 and a cylindrical peripheral surface 28. The post member has a 
splined bore 29 extending through the upper surface 27 in a vertical 
direction and including vertical splines arranged in a parallel 
arrangement around the surface thereof. 
Upon the post is mounted a cap member 30 having a flat horizontal upper 
plate portion resting upon the upper surface 27 and a cylindrical sleeve 
portion surrounding and in contact with the surface 28 of the post member. 
The cap member 30 is therefore free to rotate about the vertical axis 
defined by the post member. The cap member has a central opening 31 
aligned with the opening 29 in the top of the post member. 
The cap member 30 carries at diametrically opposed positions partway up the 
sleeve portion thereof a pair of pins 32 and 33 which project outwardly to 
the sides of the cap member. The pins define a pivot axis and cooperate 
with a clevis 34 at the outer end of the suspension arm 11 as best shown 
in FIG. 4. 
The post member 26 is positioned exactly midway across the width of the 
inner member so that the vertical axis of the post lies on a central plane 
of the wheel at right angles to the wheel axis and passing through a 
midpoint of the tire 13. The pin 32 and 33 are positioned directly on 
either side of the post member 26 and thus similarly have an axis lying in 
the central plane and at right angles to the axis of the post member. The 
pivot action of the inner member relative to the outer end of the 
suspension arm 11 therefore takes place about a pivot axis lying in the 
central plane of the wheel. 
On the upper plate of the cap member 30 is attached a hydraulic motor 35 
having a flange 36 bolted to the top plate. The housing of the hydraulic 
motor is thus held stationary relative to the cap member and the hydraulic 
motor includes a splined shaft 37 projecting downwardly from the underside 
through the opening 31 in the cap member and into cooperation with the 
splined bore 29 within the post member. The supply of hydraulic fluid to 
the motor 35 by control lines (not shown) thus acts to rotate the inner 
member and therefore the wheel about the vertical axis of the post member 
with the post member rotating within the cap member relative to the 
bearing surfaces defined by the post member and the cap member. Alignment 
of the steering can thus be simply by adjusting the hydraulic motor by 
supply of fluid rather than by complex mechanical adjustments in a 
conventional arrangement. 
Upon the platform 24 at the top of the inner member is mounted a further 
post 38 which projects downwardly toward the post member 26 and has an 
axis lying coaxially with the axis of the post member 26. Onto the post 
member 38 is attached a further cap member 39 which has the form of a 
sleeve with a closed lower end allowing the cap member 39 to rotate around 
the post member 38 but held in position thereon. The cap member 39 
similarly includes a pair of pins 40 and 41 projecting outwardly to the 
sides thereof for cooperation with a clevis 42 at the upper end of a 
cylinder and piston assembly 43 forming part of the suspension arm 11. 
The suspension arm 11 is formed by a pair of side rails 45 and 46 connected 
by cross members 47 thus forming a rigid three dimensional structure held 
against twisting and allowing pivotal movement of the inner member 
relative to the outer end 34 and pivotal movement of the suspension arm 
relative to a pin 48 provided on the frame member 12. The suspension arm 
thus holds the pin 48 parallel to the axis of the pins 32 and 33 with the 
direction of the axis being parallel to the direction of movement of the 
vehicle. The suspension arm further includes a bell crank section 50 
coupled to a conventional resilient suspension system 51 including a 
spring and shock absorber so that the suspension arm can pivot in a 
clockwise direction as shown in FIG. 1 under forces from a changing ground 
height against a spring resistance provided by the suspension system 51. 
The suspension arm further includes the cylinder and piston assembly 43 
together with a further cylinder and piston assembly 52. Each of the 
cylinders is coupled at its lower end to the suspension arm. The upper or 
piston rod end of the cylinder 52 is coupled to a suitable portion of the 
frame indicated at 12A which is rigidly connected to the frame 12 and thus 
holds the inner end of the piston rod in fixed location. The piston rod 
end of the cylinder 43 carries the clevis 42 which is coupled to the pins 
of the upper cap member. Fluid connections 54 are provided between the 
cylinders so that any fluid forced out of one of the cylinders 43, 45 by 
movement of the suspension arm is injected into the other cylinder 43, 45 
as best shown in FIG. 1 thus moving the piston rod in the cylinder and 
acting to maintain the upper cap member and upper post member directly 
vertically above the lower cap member and lower post member to hold the 
plane of the wheel vertical and properly stabilized. 
The clevis 42 includes rubber bushings 42A allowing a slight amount of play 
between the clevis and the pins 40, 41 so that the central plane of the 
wheel can twist slightly from the vertical due to changes to in camber of 
the road surface on which the wheel is running to tend to maintain the 
central plane of the wheel as far as possible at right angles to the 
ground surface. However within these limitations, the central plane of the 
wheel is maintained generally vertical at all times regardless of the 
position of the suspension arm due to the cooperation between the 
suspension arm and the linkage defined by the cylinders 43 and 45. In 
addition the position of the coupling between the outer end of the 
suspension arm and the inner member directly on the central plane of the 
wheel and below the central axis of the wheel provides a stable structure 
in which there is no cantilever effect and in which the central plane of 
the wheel can be maintained generally vertical. 
A drive system for providing drive to the wheel is omitted from FIGS. 2 and 
4 for convenience of illustration. In FIG. 1 and in FIG. 3 are shown two 
alternative arrangements for communicating drive from a suitable drive 
system to the rim member 14. 
As best shown in FIG. 3, there is provided a disc 60 which is coupled at 
its outer periphery to the outside edge of the rim member 14 by bolts 61 
extending into openings 62 in the outside surface of the rim member. The 
disc which may be a complete disc or may have portions cut out for 
reduction in weight thus forming a spider which extends from the periphery 
to a central boss 63 projecting through a hole 64 in the outer plate 17 of 
the inner member. The boss 63 in the arrangement shown in FIG. 3 can be 
directly coupled to a mechanical drive arm and universal joint arrangement 
(not shown) extending from a main power unit of the vehicle. The drive to 
the wheel thus passes through the open face 18 of the hollow inner member, 
past the suspension system and steering system to the boss 63 and from 
there communicates the drive around the outside of the wheel and 
particularly the inner member of the wheel to the rim member. 
In the arrangement shown in FIG. 1, in place of the mechanical drive 
linkage and boss is provided a hydraulic drive assembly generally 
indicated at 65 having a housing mounted upon the end plate 17 and a drive 
shaft extending through the opening 64 in the end plate 17 and 
communicating with the disc 60. 
Turning now to FIG. 5 there is shown a side elevational view of an inner 
member 15A suitable for a wheel which is a non steering wheel. It is as a 
non powered wheel but may include a drive system similar to that described 
above. In this case the inner member 15A includes two pins 70 and 71 
mounted on the inside surface of the inner member and defining a 
horizontal axis transversely of the inner member at substantially the same 
height as the axis defined by the pins 32 and 33 in the embodiment 
previously described. In this case the suspension arm is indicated at 11A 
and is modified so that it cooperates with the pin 70 and 71 in the 
pivotal action substantially as previously described. A top pin and cap 
member 39 identical to that shown in the first embodiment are also 
provided for cooperation with the outer end of the cylinder 43 as 
previously described but not shown for convenience in FIG. 5. 
The embodiment described above has the following advantages: 
1. The point of engagement between the suspension arm and the wheel is 
positioned right in the centre of the wheel or on the central plane of the 
wheel so that there is no cantilever effect. 
2. The construction is relatively simple and includes less parts and 
particularly no ball joints which are a particular problem in conventional 
suspension and steering systems. 
3. The wheel is in constant position regardless of the orientation of the 
suspension arm and therefore there is no disturbance of the geometry 
including the camber, castor and toe in which arise in conventional 
steering and suspension systems. 
4. The tire periphery is retained continuously horizontal and accordingly 
provides constant traction regardless of interference from changes in the 
level of the road surface. 
5. The system accomodates a full independant suspension without the 
necessity to stabilize wheels by tie bars which increase the unsuspended 
mass. 
6. The constant location of the tire relative to the ground prevents or 
reduces the amount of wear of the tires. 
7. The absence of twisting of the tires with the ground allows the use of 
very low profile tires which reduce rolling friction and reduce 
unsuspended mass. It may be possible to use solid tires in view of the 
very much reduced requirement for flexure of the tire surface. 
8. In view of the very low number of parts, the system is highly reliable 
with reduced requirement for maintenance. 
9. The system does not require highly complex alignment techniques to set 
the various angles of the wheels required for conventional suspension 
systems. 
Since various modifications can be made in my invention as hereinabove 
described, and many apparently widely different embodiments of same made 
within the spirit and scope of the claims without departing from such 
spirit and scope, it is intended that all matter contained in the 
accompanying specification shall be interpreted as illustrative only and 
not in a limiting sense.