Komatsu PC200-8M0 Shop Manual page 187

402 Hydraulic system, Part 2
Functions and operation by valve
In boom "NEUTRAL" operation
q When the boom is operated to "NEUTRAL" position, the pressurized oil flowing inside poppet (5)
through orifice (a) of poppet (5) is stopped by pilot piston (2).
The holding pressure of boom cylinder bottom exerts a right-hand force on the left side of ring-shaped
q
area (S), of which outside diameter is poppet (5) diameter (d1) and of which inside diameter is seat
diameter (d2).
The combined force of right-hand force on area (S) and the spring force of spring (4) moves poppet (5)
q
to the right.
q The circuit from control valve to boom cylinder bottom shuts off, then the oil pressure of the boom cylin-
der bottom side is kept.
PC200, 200LC, 220, 220LC-8M0
SEN06120-00
45
10-402