Komatsu PC200-8M0 Shop Manual page 235

403 Hydraulic system, Part 3
PPC valve
2) When signal current is very small (coil is energized)
When a very small signal current flows to coil (4), coil (4) is energized, and a propulsion force is gener-
q
ated on the right side of plunger (5).
q Push pin (6) pushes spool (2) to the right, and pressurized oil flows from port (P) to port (C).
Pressures on port (C) increases and the force to act on surface (a) of spool (2) and the spring load on
q
spring (3) become larger than the propulsion force of plunger (5).
q Spool (2) is pushed to the left, port (P) is shut off from port (C) and ports (C) and (T) are connected.
q Spool (2) moves so that the propulsion force of plunger (5) may be balance with pressure of port (C) +
spring load of spring (3).
q The circuit pressure between the EPC valve and the control valve is controlled in proportion to the size
of the signal current.
PC200, 200LC, 220, 220LC-8M0
SEN06121-00
37
10-403