SYSTEM / Hydraulic System

Forward Travel Circuit

• When setting the forward/reverse lever to the forward position, the forward selection solenoid valve of the forward/reverse selection solenoid valve is excited and the spool moves rightward.

• Therefore, the circuit between the DE pump solenoid valve and the displacement angle cylinder is connected, and pressure oil from the HST charging pump is supplied to the displacement angle control cylinder.

• As pressure oil from the HST charging pump is supplied to the left side of displacement angle control cylinder, the piston of the displacement angle cylinder moves rightward.

• Therefore, the HST pump displacement angle is changed from the neutral position and the HST pump delivers pressure oil.

• Pressure oil from the HST pump is supplied to the HST motor.

• Therefore, the HST motor rotates to the forward direction.

Reverse Travel Circuit

• When setting the forward/reverse lever to the reverse position, the reverse selection solenoid valve of the forward/reverse selection solenoid valve is excited and the spool moves leftward.

• As pressure oil from the HST charging pump is supplied to the right side of displacement angle cylinder, the HST pump displacement angle direction is reversed in a forward circuit case.

• Therefore, the HST motor rotates to the reverse direction.