Control Valve; Hydraulic Circuit; Feature; Outline - Kubota KX080-3 Workshop Manual

WSM KX080-3 Mechanism
C.Control Valve
a. Feature
1 Section composition
2 Maximum load pressure
selection (system change)
3 Spare port
4 Signal circuit
5 Travel speed change
when using the dozer
6 Traveling
7 Others
b. Outline

(1) Hydraulic circuit

1 Three-pump LS Front attachment (Boom, arm, bucket, swing, SP1)
Traveling
Travel + Front attachment
Swivel: Dozer, SP2
2 Pressure Travel
Front attachment
Swivel, dozer, SP2 (Service port 2)
Travel + Front attachment
3 Checking the Main back-pressure check valve
back pressure
Oil cooler back-pressure check valve
4 Overload relief Arm (bottom)
Arm (R), boom (B/R), bucket (B/R)
Dozer (B)
Dozer (R)
SP1 (Service port 1)
5 Others Swing (R)
SP2, swing (B)
Center open valve ( 14): 3-gang; Swivel, dozer, SP2
P3 confluence valve ( 14)
Center open valve ( 14): 2-gang; Travel left and right
Travel selector valve ( 18)
Center closed valve (LS) ( 18): 4-gang monoblock; Arm, bucket, SP1, boom
Center closed valve (LS) ( 14): 1-gang; Swing
Center closed valve (LS) (other spec.) ( 14): 2-gang; Future option Angle blade, 2-piece boom
High pressure selection = Check valve + LS bleed orifice ( 0.5)
SP1 maximum flow limit: By proportional valve
SP1 flow rate: 100 L/min ,26.4 GPM
SP2 maximum flow limit: Mechanical stopper
SP2 flow rate: 67 L/min, 17.7 GPM
AI signal: PP1
Travel control signal: PP2 (P1 and P2 to the left or right travel section)
LS control signal: PP3
P3 pump flow to join the LS system circuit by PP2 + PP3 (travel + LS front system control)
Similar to a variable displacement pump system (speed change by P3 horsepower shift)
Left/right travel pumps acting independently
Boom s anti-drift valve: None (Leak reduction thanks to the holding valve)
IV-M-26
P1 + P2
P1, P2
Travel : P1, P2
Front attachment : P3
P3
2
29.4 MPa, 300 kgf/cm , 4267 psi
2
27.4 MPa, 280 kgf/cm , 3983 psi
2
20.6 MPa, 210 kgf/cm , 2987 psi
Travel : 29.4 MPa, 300 kgf/cm
Front attachment : 20.6 MPa, 210 kgf/cm
2
0.4 MPa, 4.1 kgf/cm , 58.0 psi
2
0.1 MPa, 1.0 kgf/cm , 14.5 psi
2
30.4 MPa, 310 kgf/cm , 4410 psi
2
31.4 MPa, 320 kgf/cm , 4555 psi
2
27.5 MPa, 280 kgf/cm , 3990 psi
2
11.8 MPa, 120 kgf/cm , 1712 psi
2
20.6 Mpa, 210 kgf/cm , 2987 psi
Anti-void
Stop valve
IV Hydraulic System
2
, 4267 psi
2
, 2987 psi