Komatsu Galeo BR380JG-1E0 Shop Manual page 106

10 Structure, function and maintenance standard
(2) When load on actuator is large and pump discharge pressure is high
Outline
When the load is large and pump discharge
q
pressures (PP1) and (PP2) are high, the force
pushing spool (3) to the right becomes larger
and spool (3) will be moved to the position
shown in above figure.
Part of the pressure to be conducted from port
q
(C) to LS valve flows from port (B) to port (C)
and (D) via LS valve. At the end this flow, level
of this pressure becomes approximately half of
pump pressure (PP2).
Operation
When port (E) and port (G) of the LS valve are
q
connected, this pressure from port (J) enters
the large diameter end of servo piston (9),
stopping servo piston (9).
If pump pressure (PP2) increases further and
q
spool (3) moves further to the right, pump pres-
sure (PP1) flows to port (C) and acts to make
the pump delivery the minimum.
BR380JG-1E0
When servo piston (9) moves to the right,
q
springs (4) and (6) are compressed and push
back spool (3).
When spool (3) moves to the left, the opening
q
of port (C) and port (D) becomes larger.
As a result, the pressure on port (C) (= J) is
q
decreased and the rightward move servo pis-
ton (9) is stopped.
The position in which servo piston (9) stops at
q
this time is further to the right than the position
when pump pressures (PP1) and (PP2) are
low.
SEN01351-00
19