Komatsu PC600LC-7 Manual page 75

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
2) Operation in direction of decrease of pump discharge amount (min. angle)
Operation
• When signal pressure PECN goes down, piston
(8) moves to the left and stops at a point where
the pressure in chamber c balances the pressure
of springs (4) and (4A).
• At the same time, arm (6) uses servo piston (19)
as a fulcrum and sways to the left in the same
way as piston (8). This moves guide spool (13) to
the left.
• When guide spool (13) moves, port a and port h
are closed and port h is connected to drain
chamber e. As a result, servo piston chamber j is
also interconnected with drain chamber e
through port i and port h.
PC600, 600LC-7
HYDRAULIC PUMP (PISTON PUMP)
• At the same time, port a is interconnected with
port d, so the oil flows through port g to servo pis-
ton chamber f, pushes servo piston (19) to the
left, decreases the swash plate angle in the main
piston pump and decreases the pump discharge
amount.
• When servo piston (19) moves, arm (6) rotates
counterclockwise with its center at pin (7). Guide
spool (13) is moved to the right and closes port
a, port d and port h, so the discharge decreases
by an amount that matches signal pressure
PECN.
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