Komatsu PC200-8M0 Shop Manual page 196

SEN06120-00
Operation
When pilot pressure (P) is shut off (high pres-
sure setting)
q Since pilot pressure (P) is shut off, piston (2) is
pressed to the left by force of spring (3). [Load
at installed length of spring (1) < Load at
installed length of spring (3).]
The load at installed length of spring (1)
q
becomes maximum, inducing high-pressure
setting.
q Passage (B) is interconnected to the drain cir-
cuit via passage (C) and chamber (D).
54
10-402
402 Hydraulic system, Part 2
Functions and operation by valve
When pilot pressure (P) is supplied (low pres-
sure setting)
When pilot pressure (P) is supplied, the pilot
q
pressure is transmitted to part (A) through pas-
sage (B).
q The pilot pressure acts on the pressure receiv-
ing diameter at part (A) [(d1) — (d2)] of piston
(2).
q Piston (2) compresses spring (3) by receiving
pilot pressure and moves to the right until it
contacts holder (4).
q Since spring (1) is expanded and reducing its
load at installed length, the set pressure is low-
ered.
q The amount of pressurized oil for stroke of pis-
ton (2) is drained from passage (C) via cham-
ber (D) .
PC200, 200LC, 220, 220LC-8M0