FIELD OF INVENTION
This invention relates to a power steering linkage system for wheel rotation
span control. This is comparatively more reliable than traditional system.
BACKGROUND/PRIOR ART OF THE INVENTION
Front wheels are generally the steered wheels for tractors & other vehicles. In
the linkage mechanism of power steering system of a tractor (Fig. 1)) some of
the major components are steering cylinder assembly with piston & rods, King
pin assembly and steering arms. Generally, steering cylinder assembly is
mounted on rear side of front axle. Steering cylinder rods with one end
connected with piston have other end connection to steering arms through a
universal ball joint. Other end of steering arm is connected to kingpins which
along with wheel & hub assembly are fitted on front axle and are free to rotate
along with longitudinal axis. When operator turns the steering wheel, hydraulic
oil supply guided by the steering gear unit forces the movement of steering
cylinder piston & hence steering rods. This results in rotation of kingpins and
wheel hub assembly.
Conventionally, a projection is provided at the bottom of kingpin housing of
front axle assembly (fig. 2) which sets the limits to turning angle of wheel hub.
In the conventional Front axle, collars are provided at bottom of king pin
assembly for controlling the span of rotation of front wheel hub. Hub rotates
due to torque transferred from steering arms. After particular span of rotation,
the collar of King pin Assembly (also called spindle & pin assembly) mates with
that of king pin housing & thus stops the rotation.
The drawback of the aforesaid system is that, it produces stress in King pin
Assembly due to reactive forces, which is commonly used in the tractors.
OBJECTS OF THE INVENTION
The primary object of the present invention is to provide a power steering
linkage system for wheel rotation span control which overcomes disadvantages
associated with the prior art.
Another object of the present invention is to provide a power steering linkage
system for wheel rotation span control which is simple in construction and
efficient.
Further object of the present invention is to provide a power steering linkage
system for wheel rotation span control which is cost effective and reliable.
SUMMARY OF THE INVENTION
The above mentioned system of the instant invention comprises of cost effective
front axle, wherein king pin housings have a flat bottom i.e. without
projections. This provision reduces the raw material and machining cost for
front axle king pin housing as well as for front wheel hub.
This invention discloses a power steering linkage system for wheel rotation
span control wherein steering limits are controlled by steering cylinder wherein
the span of wheel rotation is constrained by the movement of piston and rod in
steering cylinder instead of front axle king pin housing.
Further, in this system of proposed application, the stresses due to reaction
forces are applied at steering cylinder which are comparatively more capable
for this purpose.
-4-
STATEMENT OF INVENTION
According to this invention, there is provided a power steering linkage system
for wheel rotation span control comprising of cylinder housing fixedly mounted
on front axle of vehicle, wherein the housing accommodates a cylinder rod and
is provided with a piston, characterized in that flat bottom surface of king pin
housing as shown in fig. 6.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Further objects and advantages of this invention will be more apparent from
the ensuing description when read in conjunction with the accompanying
drawings and wherein:
Fig. 1 shows: power steering linkage.
Fig. 2 shows: conventional wheel rotation span control mechanism.
Fig. 3 shows: power steering linkage system of the present invention.
Fig. 4 shows: linkage system according to the present invention when piston
butts with gland in case stopper on axle is removed.
Fig. 5 shows: sectional view of linkage system of the present invention.
Fig. 6 shows: King pin housing bottom surface without collar.
DETAIL DESCRIPTION OF THE PRESENT INVENTION WITH REFERENCE
TO THE ACCOMPANYING DRAWINGS:
The present invention is directed to a power steering linkage system for wheel
rotation span control.
-5-
Reference may be made to fig. 3 and 4, wherein cylinder housing is fixedly
mounted on front axle of tractor, wherein a cylinder rod is accommodated
inside said cylinder housing.
8
The cylinder rod moves inside the cylinder housing as it is driven by means of
oil flowing inside the cylinder housing.
Further, a gland is fixedly provided with the cylinder rod to travel with the
cylinder rod. Piston is fixed with the cylinder housing. When the gland is
applied with force of oil, it moves in the direction of force alongwith the rod.
Thc movement is forced to stop when the gland butts with said piston.
When the steering cylinder rod reaches its limit, rotation of front wheel of
tractor also stops. Hence the wheel rotation span is controlled inside the power
steering cylinder. Considering this, the projection provided in front axle king
pin housing is eliminated as shown in fig. 6, as this projection was provided to
control this rotation span only.
Advantageous features
- Reduction in weight.
- Reduction in raw material and machining cost for front axle king pin
housing and front wheel hub.
- Prevention of stress in hub.
- Reliable.
It is to be noted that the present invention is susceptible to modifications,
adaptations and changes by those skilled in the art. Such variant embodiments
employing the concepts and features of this invention are intended to be within
the scope of the present invention, which is further set forth undcr the
following claims:-

WE CLAIM:
1. A power steering linkage system for wheel rotation span control
comprising of cylinder housing fixedly mounted on front axle of vehicle,
wherein the housing accommodates a cylinder rod and is provided with a
piston, characterized in that flat bottom surface of king pin housing as
shown in fig. 6.
2. A power steering linkage system as claimed in claim 1, wherein steering
limits are set in steering cylinder wherein the span of wheel rotation is
constrained by the movement of piston and rod in steering cylinder.
3. A power steering linkage system as claimed in claim 1 or 2, wherein the
stresses due to reaction forces are applied at steering cylinder which are
comparatively more capable for this purpose.
4. A power steering linkage system as claimed in any of the preceding
claims, is associated with the advantageous features such as herein
described.
5. A power steering linkage system for wheel rotation span control
substantially as herein described with reference to the accompanying
drawings.