Doosan Power Train D50S-5 Specifications Systems Operation Testing & Adjusting Disassembly & Assembly page 20

(2) INCHING VALVE
◆ FUNCTION
The INCHING VALVE controls the pressure of oil
entering CLUTCH and smoothens the CLUTCH
contact.
In addition, by enabling the vehicle to move
smoothly at high RPM, it provides fast
functionality of the implement in low speed.
◆ OPERATION
When the INCHING PEDAL is not pressed, the
oil from the main pressure line "A" is fed to
ACCUMULATOR VALVE through valve and "D."
When the INCHING PEDAL is pressed, SPOOL
moves toward left, isolating the main pressure
line "A" stopping oil supply. The oil in the
ACCUMULATOR is drained through "C" via "D"
lowering pressure at CLUTCH.
(3) ACCUMULATOR VALVE
◆ FUNCTION
Smoothens CLUTCH operation by enlarging the
time for pressure rise since from the CLUTCH
contact and beginning of slip.
◆ OPERATION
When the INCHING PEDAL is pressed and let
free, oil enters "E(1st orifice)" from inching to
move piston to right. Then, pressure rises slowly
to open "F(2nd orifice)." When the piston reaches
right side, pressure rises up to the relief setting
value.
In the oil path of the accumulator valve plug to
solenoid valve is #100 screen which filters
foreign material.
Power Train
Therefore, wash the plug when replacing the T/M
oil.
(4) SOLENIOD VALVE
◆ FUNCTION
Supplies the oil from accumulator to each clutch
according to the change of step.
◆ OPERATION
When the shift lever is moved, the spool in the
solenoid valve moves toward bottom by electric
signal, forming oil path.
The oil from accumulator enters "G", flows
through the internal path of solenoid valve, and
fed to clutch via "H."
When the shift lever is at neutral position, the
electric signal us cut-off, the spool moves
upwards by the force of the spring in the solenoid
valve, forming an oil path from "G" to "C(tank)"
removing residual pressure in the clutch.
19 System Operation