d. Main Pressure Regulator.
This valve assembly consists of a
regulator valve (housing a check ball, spring, and retainer),
calibrated spring, and a reverse boost valve in a bore.
This valve establishes a main pressure schedule.
Oil from the main
pressure pump flows through an orifice to the upper end of the valve
and pushes down on the top of the valve against the calibrated
spring.
This pressure on the spring controls the oil flow through
the regulator valve. Oil from the main pressure pump also flows into
the valve bore and through an internal passage to the upper end of
the valve.
When high fluctuations in pressure from the main pressure pump occur,
hydraulic pressure offsets the check ball and pushes down on the
valve, correcting the main pressure schedule.
This continues until
oil pressure flows through the orifice, directing pressure to the
upper end of the regulator valve, or until the high fluctuations
diminish.
Three pressures change the main pressure schedule:
lockup, brake
apply, and reverse pressure.
Upon application of lockup pressure,
the regulator valve moves down, decreasing main pressure.
When
applying brake apply or reverse pressure to the bottom of the
regulator valve, the valve moves up, increasing main pressure.
e. Signal Main Regulator Valve (fig. 1-20).
The signal main
regulator consists of a valve assembly, with a check ball and spring
retainer, and a calibrated spring in a bore. This valve establishes
regulated pressure for control functions.
Main pressure feeds into
the valve bore and through an internal passage to the left of the
valve. Pressure at the left end forces the valve right against the
calibrated spring force, establishing signal main pressure.
f. Solenoid Controls (fig. 1-21).
Nine identical solenoids
control pressure at the end of various hydraulic operating valves.
These solenoids are identified as A, B, C, D, E, H, J, K, and X.
Energizing a solenoid causes a plate (which is normally holding a
check ball down) to lift and allows hydraulic pressure to raise the
ball and relieve pressure through an orifice in the solenoid.
The
solenoid orifice relieves hydraulic pressure faster than the oil
supplied through the control orifice.
If the solenoid is not energized, pressure increases and moves the
valve against the exerted pressure on the opposite end of the valve.
28
OD1710
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