Komatsu PC20R-8 Shop Manual page 81

5. Area ratio of pressure compensation valve
FUNCTION
. The pressure compensation valve determines the compensation characteristics by carrying out fine adjustment
of the area ratio (S2/S1) between area S2 of reducing valve (1) and area S1 of flow control valve (2) to match the
characteristics of each actuator.
S1=Area of flow control valve (2) ± Area of piston (3).
S2=Area of reducing valve (1) ± Area piston (3).
P
PA
S
1
2
P
Area ratio (S1:S2) and compensation characteristics
. When ration is 1.00 :
[Pump pressure P ± spool notch upstream pressure P
P
P (=A)] and oil flow is divided in proportion to area of opening of spool.
A
. When ratio is more than 1.00 : P
a proportion less than area of opening of spool.
. When ratio is less than 1.00 : P
proportion more than area of opening of spool.
Valve
Arm
Travel
Boom
Bucket
PC20R-8 PC27R-8
A
P
± P >P
P PA LS
± P <P
P PA LS
Ratio of area S1 and S2
Ratio
0.98
1.00
0.95
1.00
3
]6[LS circuit pressure P
PA
± P (=A) and oil flow to side receiving compensation is divided in
A
± P (=A) and oil flow to side receiving compensation is divided in a
A
Valve
Boom swing
Blade
Hammer
Swing
T
P
A
S
2
P
1
LS
RKP00760
± actuator circuit pressure
LS
Ratio
0.98
0.98
1.00
0.95
10-63