Komatsu Utility PC12R-8 MISTRAL, Shop Manual

Page: 74 / 324

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 ( S1 / S2 ) 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 of piston (3).
Area ratio (S1:S2) and compensation characteristics
. When ratio is 1.00 :
[Pump pressure P
P
± spool notch upstream pressure P
PA
] 6 [ LS circuit pressure P
LS
± actuator circuit pressure
P
A
(= A )] and oil flow is divided in proportion to area of opening of spool.
. When ratio is more than 1.00 : P
P
± P
PA
> P
LS
± P
A
(= A ) and oil flow to side receiving compensation is divided in
a proportion less than area of opening of spool.
. When ratio is less than 1.00 : P
P
± P
PA
< P
LS
± P
A
(= A ) and oil flow to side receiving compensation is divided in a
proportion more than area of opening of spool.
Ratio of area S1 and S2
Valve Ratio Valve Ratio
Arm 0.98 Boom swing 0.98
Travel 1.00 Blade 0.98
Boom 0.95 Hammer 1.00
Bucket 1.00 Swing 0.95
10-56
PC12R-8 PC15R-8
RKP00761
3
A T
P
A
S
2
P
P
P
LS
1
2
S
1
P
PA