The design of the servo sleeve cuts off the flow of oil to the
control piston as soon as the hanging ring reaches the same angle as
the servo valve.
This prevents the control piston from continuing
its travel beyond the steer degree desired. The hanging ring remains
at that position until the servo valve moves again.
Thus, small
rotation of the servo valve causes a small (and equal) rotation of
the hanging ring; a larger rotation of the servo valve causes a great
rotation of the hanging ring. In reality, the servo sleeve "follows"
the servo valve and "catches up" with it when the servo valve stops.
Since the pressure produced in the hydrostatic pump varies with the
effort required for steering the vehicle, the pressure to control the
effort also varies.
To regulate control pressure, the system uses
the control pressure regulator valve.
The valve responds to high
kidney pressure (directed from the shuttle valve) and main pressure.
When this valve moves right it lowers pressure, and when it moves
left it raises pressure.
A secondary control pressure regulator is also used to regulate
control pressure. The secondary control pressure regulator responds
to low kidney pressure directed from the shuttle valve.
When this
valve moves left it raises control pressure, and when it moves to the
right it lowers control pressure.
Another component in the control circuit is the stroke limiter. When
operating conditions overload the hydrostatic pump (approx. 5000
psi), the excessive output pressure pushes the valve to a position
which interrupts the control pressure circuit actuating the control
This action overrides steer control to the extent of
reducing steer to the degree possible under the overload conditions.
2.
The X1100-3B Transmission Final Drive (fig. 1-56).
The following paragraphs describe the final
drive,
its
major
components, and operational characteristics.
The final drive is a self-contained,
heavy-duty, planetary gear, speed reduction unit.
The input spline
is integral with the planetary sun gear. The planetary ring bolts to
the final drive housing, and therefore does not rotate.
The
planetary carrier, with planet pinion gears, is splined to the output
shaft.
The final drive unit is identical for both left and right
transmission outputs. The final drive unit weighs approximately 940
lbs.
The oil
supply, stored in the bottom of the housing, provides both
cooling
and lubrication for the unit.
The final drives use the
"splash
method" for lubrication, since the pinion gears run in oil
all the
time and carry the oil around the housing with
60
OD1710
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