Komatsu PC88MR-10 Shop Manual page 160

10 Structure and function
Control valve
Since the open area of the right and left travel valve spool is small, the differential pressures between LS
pressures [(PLS1) and (PLS2)] and pump discharged pressures [(PP1) and (PP2)] are large.
The differential pressure between pump discharged pressure (PP1)/(PP2) and LS pressure (PLS1)/
(PLS2) reaches the load at installed height of spring (2) (2.45 MPa {25.0 kg/cm
Spool (1) moves to the left.
Pump circuits (PP1) and (PP2) are interconnected to tank circuit (T).
Excessive oil (maximum discharged volume - demand flow) flows through.
The excess oil other than the demand flow corresponding with the travel of the right and left travel valve
spools (pump maximum flow - demand flow) is drained into tank circuit (T).
When right and left travel valves are operated
Function
When the right and left travels are operated and they demand the maximum flow, the drain into tank circuit
(T) is stopped and all of pump discharged volume (Q) is supplied to the right and left travel circuits.
Since the merge-divider spool is located at the divide position, pump discharged pressures (PP1) and
(PP2) are divided from each other.
LS pressures (PLS1), (PLS2), and (PLS3) are divided.
The swash plate angle becomes maximum and the discharged volume becomes maximum. (For details,
see "merge-divider valve")
Operation
When the full operation of the right and left travels are performed, LS pressures (PLS1) and (PLS2) are
generated and they act on the left side of spool (1). [(PP1)/(PP2) and (PLS1)/(PLS2) are divided from
each other].
10-82
2 }).
PC88MR-10