Komatsu Galeo PC138US-8 Shop Manual page 168

SEN02549-02
Area ratio of pressure compensation valve
Function
The pressure compensation valve slightly
q
adjusts the ratio (S2) and (S1) of the area (S1)
on the left side of the flow control valve (2) and
the area (S2) on the right side of the pressure
reducing valve (1) to suite the characteristics
of each actuator and determines the compen-
sation characteristics.
S1 : Area of the flow control valve (2) – area of the
piston (3)
S2 : Area of the pressure reducing valve (1) –
area of the piston (3)
34
10 Structure, function and maintenance standard
Area ratio (S1) : (S2) and compensation charac-
teristics
When the ratio is 1.00 :
q
The expression [Pump (discharge) pres-
sure (PP) – Spool notch upstream pres-
sure (PPB)] C [LS circuit pressure (PLS) –
Actuator circuit pressure (PA) (= A)] can
be held, and the flow is distributed as per
the spool opening area ratio.
When the ratio is more than 1.00:
q
The expression (PP) – (PPB) > (PLS) –
(PA) (= A) can be held, and the flow is dis-
tributed less than the spool opening area
ratio.
When the ratio is less than 1.00:
q
The expression (PP) – (PPB) < (PLS) –
(PA) (= A) can be held, and the flow is dis-
tributed more than the spool opening area
ratio.
PC138US, USLC-8