TM 5-2410-240-23-1
0007
HYDRAULIC SYSTEMS CONTINUED
Right Side Hydrostatic Pump Operation
0007
When the engine is running, the shaft (Figure 5, Item 13) and the barrel (Figure 5, Item 10) rotate. The port plate
(Figure 5, Item 8) and the swashplate (Figure 5, Item 12) are stationary within the pump housing. The spring
(Figure 5, Item 9) maintains a force against the barrel and the port plate (Figure 5, Item 8). There are nine pistons
(Figure 5, Item 11) in the barrel. When the barrel is rotating, each piston follows the angle of the swashplate. If the
angle of the swashplate is zero, pistons do not move in and out of the barrel and there is no oil flow.
Charge oil from the charge pump (Figure 5, Item 6) maintains oil pressure in the pump in order to perform the
following tasks:
Keep the barrel (Figure 5, Item 10) full of oil.
Provide makeup oil for internal loss of oil due to leakage.
Lubricate and cool the pump and motor components.
Provide pilot oil to the proportional solenoid valve (Figure 5, Item 4) in order to shift the actuator piston
(Figure 5, Item 1) and change the angle of the swashplate (Figure 5, Item 12).
The actuator piston (Figure 5, Item 1) determines the position of the swashplate (Figure 5, Item 12). The machine
ECM interprets signals from the speed and direction control and sends pulse-width modulated signals to solenoids
(Figure 5, Item 2) on either side of the proportional solenoid valve (Figure 5, Item 4). As the proportional solenoid
valve shifts to either direction, signal oil from the passage (Figure 5, Item 3) is directed to the corresponding end of
the actuator piston. As the actuator piston begins to move, the angle of the swashplate begins to increase. As the
piston (Figure 5, Item 11) follows the swashplate, pistons begin to move in and out of barrel (Figure 5, Item 10). As
the piston moves out of the barrel, oil is drawn from the passage of the port (Figure 5, Item 5) of the drive loop
through the port plate (Figure 5, Item 8). As the piston follows the swashplate and the piston moves into the barrel,
oil is pushed through the port plate into the passage to the port (Figure 5, Item 7) of the drive loop. As the angle of
the swashplate increases, the output flow of the pump also increases.
0007-6
