TM 5-2410-240-23-1
0010
ELECTRO-HYDRAULIC CONTROLS CONTINUED
7. Left Pivot Turn Continued
As a result of the duty cycle settings, the left hydrostatic drive motor remains at maximum displacement. For the left
side hydrostatic pump (Figure 14, Item 7), pilot oil flows from the line (Figure 14, Item 10) through the proportional
solenoid valve (Figure 14, Item 11) into the passage (Figure 14, Item 9) and to the case drain. The pressure in the
passage (Figure 14, Item 12) remains equal to the pressure in the passage (Figure 14, Item 8). The springs on
each side of the actuator piston (Figure 14, Item 13) center the piston and the swashplate remains at a zero angle.
Since the left side hydrostatic pump swashplate is at a zero angle, the left drive loop of the hydrostatic system is in
a hydraulic lock and the left track does not move.
Inside the right hydrostatic pump (Figure 14, Item 1), the proportional solenoid valve (Figure 14, Item 3) shifts to the
left. Pilot oil flows from the line (Figure 14, Item 5) through the proportional solenoid valve into the passage
(Figure 14, Item 6) and then into the chamber of the actuator piston (Figure 14, Item 14). Inside the chamber, the
oil overcomes the force of the opposite spring and the actuator piston shifts to the left.
As the actuator piston (Figure 14, Item 14) shifts to the left, oil flows from the chamber of actuator piston into the
passage (Figure 14, Item 2) and then through the proportional solenoid valve (Figure 14, Item 3) and the passage
(Figure 14, Item 4) to the pump case drain.
As a result, displacement of the right side hydrostatic pump (Figure 14, Item 1) increases, and oil flows from the
pump to the right hydrostatic drive motor. As the oil flows through the motor, the motor rotates, causing the right
track to move forward, and the machine turns to the left while pivoting on the left track.
Figure 14. Hydraulic Oil Flow for Left Pivot Turn.
0010
