Land vehicles – Wheeled – Running gear
Reexamination Certificate
2000-04-27
2003-09-09
Culbreth, Eric (Department: 3616)
Land vehicles
Wheeled
Running gear
Reexamination Certificate
active
06616156
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to vehicle steering axle assembly components and more particularly to a new and improved steering knuckle for vehicle steering axles.
BACKGROUND OF THE INVENTION
Steering knuckles have been used in vehicles for quite some time. Steering knuckles are a component part of vehicle steering axle assemblies, including those axle assemblies used in automobiles and in commercial light-, medium- and heavy-duty trucks. Steering knuckles are associated with the steering axle of such vehicles and function to provide a mount for the spindle or hub of a vehicle wheel. Generally, steering knuckles are controlled directly by the steering linkage system of vehicles.
FIG. 1
illustrates a typical vehicle steering axle assembly generally designated by reference numeral
20
having a plurality of component parts. Steering axle assembly
20
includes an axle beam
22
that extends laterally across a vehicle. At its end portion, axle beam
22
includes a king pin bore
24
.
Vehicle steering axle assembly
20
also includes a steering knuckle/spindle
28
having a steering knuckle portion
30
with an integrally forged spindle portion
32
. Steering knuckle portion
30
includes upper and lower king pin bores
34
,
36
, which are coaxially aligned. Steering knuckle portion
30
also includes a steering arm mounting bore
38
and a tie rod arm mounting bore
40
.
As shown, a steering linkage system of the vehicle typically includes a steering arm
42
that is connected to steering knuckle/spindle
28
when an end of the steering arm is received and fastened in steering arm mounting bore
38
by a fastener assembly
44
. A draglink
46
, at one end, is connected to steering arm
42
by a fastener assembly
47
. The other end of draglink
46
is connected to a steering control box (not shown) for effectuating steering control of the vehicle.
As further shown, conventional steering linkage systems also include a tie rod arm
48
that is connected to steering knuckle/spindle
28
when an end of the tie rod arm is received and fastened in tie rod arm mounting bore
40
by a fastener assembly
50
. Tie rod arm
48
converts torque to a tie rod end
52
, which is connected thereto. Tie rod end
52
includes the ball portion of the tie rod linkage and transfers force to a crosstube
54
, which is connected thereto. Crosstube
54
connects to a tie rod end associated with another steering knuckle positioned on the opposite side of the vehicle at the opposite end of axle beam
22
and transmits a force between the two wheel ends. This allows steering to be effectuated on both sides of the vehicle. Preferably, crosstube
54
has an adjustable thread to set front axle toe to a specified amount.
A king pin
56
is also included to attach steering knuckle/spindle
28
to axle beam
22
. King pin
56
defines a steering axis pivot for vehicle steering axle assembly
20
. King pin
56
extends through the upper and lower king pin bores
34
,
36
of steering knuckle/spindle
28
and through the king pin bore
24
of axle beam
22
. As shown, a bushing
58
is positioned between the inside surface of king pin bore
34
and king pin
56
. Similarly, a bushing
60
is positioned between the inside surface of king pin bore
36
and king pin
56
. Bushings
58
,
60
permit steering knuckle/spindle
28
to pivot about king pin
56
during vehicle steering. As further shown, a gasket
62
, a cap
64
, multiple capscrews
66
(one being shown at each end) and a grease fitting
68
are included for each of the upper and lower king pin bores
34
,
36
of steering knuckle/spindle
28
.
Still referring to
FIG. 1
, a plurality of shims
70
are typically included to establish the desired spacing between steering knuckle/spindle
28
and axle beam
22
when the parts are assembled. Furthermore, several draw keys
72
are also typically included to hold king pin
56
in place in axle beam
22
during operation. King pin
56
includes notches
73
for receiving draw keys
72
. Furthermore, axle beam
22
includes draw key holes (not shown). It will be appreciated by those skilled in the art that king pin
56
would slidably move freely within king pin bore
24
, if not for draw keys
72
holding it in place.
As further shown, the spindle portion
32
of steering knuckle/spindle
28
is blended and/or tapered at its root where it integrally connects with the steering knuckle portion
30
of the steering knuckle/spindle. The blended root construction increases the stress tolerance of spindle portion
32
. Due to high bending stresses resulting from side loads during vehicle cornering, spindle portion
32
must typically be constructed of a high strength, premium steel. In the case where an integrally forged spindle
32
is used, the entire steering knuckle/spindle
28
is forged from high strength steel.
Still referring to
FIG. 1
, a wheel hub
74
having a centrally disposed wheel hub bore
76
is positioned over spindle portion
32
of steering knuckle/spindle
28
and secured in that position so that the spindle portion extends through the wheel hub bore. Wheel hub
74
allows for mounting of the vehicle wheel (not shown), which is positioned on the end of axle assembly
20
shown in
FIG. 1. A
cylindrical brake drum
78
having a centrally disposed brake drum bore
80
is positioned over wheel hub
74
and secured in that position. Brake drum
78
allows the brake shoes (not shown) to press against it, causing friction, which, in turn, stops rotation of the vehicle wheel positioned on its end of the steering axle assembly.
FIG. 2
illustrates the assembly and/or service of a conventional steering knuckle
28
to an axle beam
22
with a king pin
56
.
FIG. 2
is included herein to illustrate some of the problems associated with the assembly and service of conventional steering axle assemblies
20
. The present invention completely eliminates those problems.
As shown in
FIG. 2
, and referring also to
FIG. 1
, the upper and lower kingpin bores
34
,
36
of steering knuckle/spindle
28
must first be brought into registration with the kingpin bore
24
of axle beam
22
. King pin
56
is then inserted through bore
34
, bore
24
and bore
36
and held in place in axle beam
22
by draw keys
72
.
Because their steering pivot axis (king pin) bores are positioned on the same piece, conventional steering knuckles, such as steering knuckle/spindle
28
shown in
FIGS. 1 and 2
, make use of a press in king pin impractical, and use of a king pin fixed within the axle beam impossible. Conventional steering knuckles require the axle beam king pin bore to allow the king pin to slide therein. As such, the axle beam king pin bore provides for a loose fit to allow the king pin to be inserted through it during assembly and service. This loose fit is a leading reason for failure of the axle beam. In particular, sliding movement of the king pin within the axle beam king pin bore over time can cause wear in that bore and cause the fit to loosen further than desired. Additionally, moisture can enter the cylindrical space between the king pin and the axle beam king pin bore, causing the king pin to be frozen in place and incapable of being removed. Under such circumstances, the steering knuckle cannot be serviced, absent practical destruction of same. In particular, the steering knuckle/spindle cannot be removed from the king pin when the king pin is frozen or otherwise stuck in the axle beam king pin bore.
Conventional steering knuckles also require draw keys to hold the king pin in place in the axle beam. The use of draw keys increases the components of the steering axle assembly, which, in turn, adds cost and weight to the assembly. In the case of commercial vehicles, this additional weight translates into reduced payload capacity.
Another deficiency of conventional steering knuckles is that any desired vertical spacing between the upper and lower sections of the steering knuckle and the end of axle beam must be provided by shims or similar components. These additional comp
Dudding Ashley Thomas
Gottschalk Michael John
Miller Lawrence Edward
Rosales, Jr. Rodolfo
Cook Alex McFarron Manzo Cummings & Mehler, Ltd.
Culbreth Eric
Fleming Faye M.
The Boler Company
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