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HYDRAULIC CIRCUIT
CASE TRAINING CENTER
AUGUST 2000
High Speed Travel Circuit
With High Speed Travel, high speeds can be achieved by setting the two-step inclination angel of the travel
motor to the smaller one. The circuit has a travel motor, which changes over to lower speed by utilizing load
pressure on the travel motor, only when traveling at high speed.
Discharged oil from A1 enters the PR port of control valve entry while discharged oil from A2 enters the PL
port of control valve entry. Each flow goes into the travel motor through the changing over of the left and
right travel spool. By these flows, the machine travels forward and backward. Electronic signals are sent to
the solenoid valve for 2 speed travel in the triple solenoid valves and the solenoid valves are changed over.
Original pilot pressure (3.9 MPa) from the C1 port of the triple solenoid valves is connected through the
central joint to D ports of the left and right travel motors. The original pressure (3.9 MPa) entered the D
ports of the left and right travel motors positions the inclination angle of the travel motor to smaller
inclination side, and make the speed faster.
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