
3-19
TRAVEL CIRCUIT OPERATION
Counterbalance valve
Turning joint
a1
a2
Ps
T1
T2
R/G
R/H
L/H
T2
a2
a1
T1
Ps
R/G
P2(BW)
P1(FW)
P2(FW)
P1(BW)
Speed change mechanism(Auto)
Valves are provided on travel motors to offer the following functions.
COUNTERBALANCE VALVE
When stopping the motor of slope descending, this valve to prevent the motor over run.
SPEED CHANGE MECHANISM (Auto)
Auto two speed control mechnism consists of two spools and spring. This valve automatically
changes motor displacement in portion to motor pressure.
1)
2)
R35Z73HC42