PART B - X1100-3B TRANSMISSION HYDRAULIC SYSTEM
1.
General.
The hydraulic system generates, directs, and controls the flow and
pressure of the hydraulic fluid (transmission oil) within the
transmission.
The hydraulic fluid serves as the power transmitting
medium to the torque converter, and the oil velocity drives the
torque converter turbine.
The hydraulic pressure operates the
various control valves and applies clutches and brakes.
The system
also provides hydraulic oil flow to the hydrostatic unit system for
operation and supercharging of the hydrosteer pump and motor.
2.
Pump Circuits (fig. 1-17).
The following paragraphs describe the hydraulic pump circuits and how
they support each other and the X1100-3B transmission.
a. Main Pressure Pump.
The turbine engine drives the main
pressure oil pump.
The main pressure pump draws oil from the
reservoir, through a check valve that prevents input oil from
entering the output pump discharge line, and directs it through the
main filter into the pressure system. The filter dump valve directs
oil back to the reservoir if the pressure drop across the filter
becomes excessive.
b. Output Oil Pump. The transmission drives this oil pump. The
output oil pump operates whenever the vehicle is moving forward.
This pump takes oil from the reservoir and directs it to the check
valve between the main pressure pump and output pump lines where two
bypass valves determine the flow of the oil.
The output pump bypass valve allows output discharge oil to return to
the reservoir to maintain a very low discharge circuit pressure when
there is no flow demand. The secondary brake coolant valve, actuated
by a signal line from the brake apply regulator, allows oil to pass
through the converter-out circuit to the primary brake coolant valve.
This additional oil acts as a coolant when applying the brakes in
forward only.
c. Control Pumps.
The hydraulic system has two hydrostatic
control system pumps.
The converter turbine drives one and the gas
turbine engine drives the other.
The control pumps pressurize main
pressure from the main pressure regulator valve before directing it
to the hydrostatic control system.
d. Scavenge Pumps.
The hydraulic system has two engine driven
scavenging pumps. The main scavenging pump and the input scavenging
pump mount in tandem to the main pressure pump. The
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