Komatsu PC88MR-10 Shop Manual page 135

When pump pressure (PAVE) is high
When load is heavy
The pressing force of spool (4) increases, and spool (3) leans towards the left side. At this time, ports (C)
and (B) are connected, and pressure which goes into the LS valve becomes pump pressure (PP).
When port (F) is connected to port (G) of the LS valve, the pressure in port (J) becomes pump pressure
(PP), and servo piston (6) moves to the right.
The pump discharged volume goes to decrease.
As servo piston (6) moves, lever (1) moves to the right and spring (2) is compressed and spring force is
increased. Consequently, spool (3) moves to the right and port (C) is disconnected from port (B), and drain
pressure ports (D) and (C) are connected.
Since pressure in port (C) reduces and the piston pressure decreases, servo piston (6) stops moving to
the right.
PC88MR-10
10 Structure and function
Main pump
10-57