402 Hydraulic system, Part 2
Functions and operation by valve
When travel lever is operated
If the right travel lever is moved to REVERSE (or FORWARD) position, the pilot pressure from the travel
q
PPC valve moves spool (7) to the left (or right).
q
Spool (7) pushes piston (3) and orifice (5) is closed. As a result, stroke limiting signal chamber (a) and
the drain circuit from the travel PPC valve are disconnected.
At this time, the pilot pressure from the travel PPC valve passes through orifice (6) of piston (4), acts on
q
the left end of piston (8) and pushes piston (8) to the right.
q
When boom RAISE (or arm IN or OUT, bucket CURL or DUMP) operation is performed, spool (1) moves
to the left.
q
Maximum travel of the spool is limited to (st1) that has reduction in travel by the amount of movement
(st2) of piston (8) to the right.
PC200, 200LC, 220, 220LC-8M0
SEN06120-00
43
10-402