Motor vehicles – Having at least one wheel both driven and steerable – Steerable wheel has exclusive axis of pivot
Reexamination Certificate
2000-06-06
2001-10-16
Hurley, Kevin (Department: 3619)
Motor vehicles
Having at least one wheel both driven and steerable
Steerable wheel has exclusive axis of pivot
C180S308000, C280S093512
Reexamination Certificate
active
06302233
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a steering axle of a vehicle having a hydrostatic front wheel drive system, and more particularly to a kingpin incorporating a hydraulic swivel coupling adapted to provide a static hydraulic connection between a hydraulic motor mounted directly on a steerable wheel and a source of a pressurized hydraulic fluid mounted on a vehicle body.
2. Description of the Prior Art
Hydrostatic vehicle drive systems have been very popular and commonly used for many vehicles of the “off-highway” type, such as industrial and farming machines, or similar vehicles. Drive wheels of such vehicles are directly driven by fluid pressure actuated hydraulic motors, often mounted directly to the drive wheels, both steerable and nonsteerable. Correspondingly, the vehicles are provided with one or more sources of pressurized hydraulic fluid mounted on a vehicle body, usually in the form of hydraulic pump(s). The vehicular hydrostatic drive system is a highly complex assembly of one or more hydraulic pumps and various valves assemblies interconnected by hydraulic fluid lines. A substantial number of vehicles having the hydrostatic transmission system are provided with a front axle (seldom with a rear axle) having both steering and driving capabilities, wherein a hydraulic motor is mounted directly to the front wheels. A series of hydraulic hoses interconnect the wheel mounted hydraulic motors to the vehicle body mounted hydraulic pump. Naturally, in operation, the hoses experience numerous cycles of bending since the position of the steerable wheels and correspondingly the wheel mounted hydraulic motors change repeatedly. It is a common problem in such a system that the flexible hydraulic hoses used to supply fluid to or from the wheel motor, tend to become rigid under the influence of the pressurized hydraulic fluid, interfere with the steering and, eventually, develop a fatigue that over the period of time could lead to a damage to the hoses.
SUMMARY OF THE INVENTION
The present invention provides a hydraulic swivel coupling assembly for a steering drive axle of a vehicle having a hydrostatic drive system, wherein a hydraulic motor assembly is directly mounted on a steerable wheel of the axle and adapted to be movable with the wheel.
The steering drive axle of the present invention comprises a pair of kingpin assemblies pivotally mounting steering knuckles to axle yokes. An upper kingpin assembly pivotally attaches the steering knuckle to the axle yoke, and, at the same time, provides a hydraulic swivel coupling between the wheel mounted hydraulic motor and the rest of the hydrostatic drive system of mounted on the vehicle, that prevents the bending of the hydraulic hoses conveying hydraulic fluid, by steering movements of the front steerable wheels.
In accordance with the preferred embodiment of the present invention, the upper kingpin assembly comprises a kingpin fixedly secured to a knuckle arm, and a block manifold pivotally coupled to the kingpin and secured to the axle yoke arm. The kingpin includes a set of axial spaced hydraulic fluid passages adapted to communicate with the complimentary set of hydraulic fluid passages formed in the block manifold, at any angular position of the kingpin.
Therefore, the novel arrangement of the steering drive axle of the present invention prevents fatiguing and damage of the hydraulic hoses, thus substantially improving the reliability of the vehicular hydrostatic transmission. Moreover, it allows the use of less expensive hard tubes instead of the flexible hoses, thus reducing the manufacturing cost of the vehicle.
REFERENCES:
patent: 1934883 (1933-11-01), Reader
patent: 2353730 (1944-07-01), Joy
patent: 2768843 (1956-10-01), Zeilman
patent: 3175849 (1965-03-01), Kelly
patent: 3225855 (1965-12-01), Sherwen
patent: 3605931 (1971-09-01), Firth et al.
patent: 3612204 (1971-10-01), Allen
patent: 3659869 (1972-05-01), Hase et al.
patent: 4043567 (1977-08-01), Kaiser
patent: 5080401 (1992-01-01), Stich
patent: 5529347 (1996-06-01), Lee
Fitch Donald W.
Oates Jonathan David
Okamuro Kenneth James
Hurley Kevin
Liniak Berenato Longacre & White
Spicer Technologies, Inc.
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