Komatsu ecot3 PC300LC-8 Shop Manual page 171

10 Structure, function and maintenance standard
3. When lowering boom
Operation
When the boom is lowered, pilot pressure from
q
the PPC valve presses pilot spool (2).
q Pressurized oil in chamber (b) inside the pop-
pet is drained via orifice (c).
q Pressurized oil of the boom bottom flows to ori-
o
fice (a) chamber (b)
and the pressurized oil in chamber (b) lowers.
As the pressure of chamber (b) lowers under
q
the pressure of port (B), poppet (5) opens.
q Pressurized oil from port (B) is led to port (A)
and then flows to the control valve.
PC300, 350-8
o o
orifice (c) drain (T),
SEN01994-01
45