Komatsu Galeo BR380JG-1E0 Shop Manual page 110

10 Structure, function and maintenance standard
2) When signal current is very small
(coil is energized)
When a very small signal current flows to coil
q
(2), coil (2) is energized, and a propulsion force
is generated on the right side of plunger (7).
Rod (6) pushe spool (5) to the right, and pres-
q
surized oil flows from port (P) to port (C).
Pressures on port (C) increases and the force
q
to act on spool (5) surface and the spring load
on spring (4) become larger than the propul-
sion force of plunger (7).
Spool (5) is pushed to the left, and port (P) is
q
shut off from port (C).
Port (C) and port (T) are connected.
q
Spool (5) moves up and down so that the pro-
q
pulsion force of plunger (7) may be balanced
with pressure of port (C) + spring load of spring
(4).
The circuit pressure between the EPC valve
q
and the LS (PC) valve is controlled in propor-
tion to the size of the signal current.
BR380JG-1E0
3) When signal current is maximum
(coil is energized)
As the signal current flows to coil (2), coil (2) is
q
energized.
When this happens, the signal current is at its
q
maximum, so the propulsion force of plunger
(7) is also at its maximum.
Spool (5) is pushed toward right side by rod
q
(6).
The maximum volume of pressurized oil is
q
conducted from port (P) to port (C), increasing
the circuit pressure across EPC valve and LS
(PC) valve to the maximum level.
Since port (T) is closed, pressurized oil does
q
not flow to the tank.
SEN01351-00
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