Simplicity Legacy Series Service & Repair Manual page 144

10 U-Type Hydrostatic Unit Service
System Description
Figure 6. Neutral
When the swashplate is at neutral (zero tilt angle) there
is no stroking of the internal axial pistons and, therefore,
no flow from the pump to the motor. See Figure 6.
FORWARD
NEUTRAL
PUMP
INPUT
SHAFT
VARIABLE
SWASHPLATE
VARIABLE DISPLACEMENT PUMP
RESERVOIR
Figure 8. Circuit Flow Diagram
FROM IMPLEMENT
CONTROL VALVE
REVERSE
CYLINDER
BLOCK
ASSEMBLY
CHARGE
PUMP
FILTER
Figure 7. Reverse
The direction of motor (output) shaft rotation depends
upon which port the fluid enters. Reversing the direction
that the swashplate is tilted from neutral (zero angle)
reverses the output shaft rotation, hence the direction of
the tractor. See Figure 7.
IMPLEMENT
RELIEF VALVE
CYLINDER BLOCK
ASSEMBLY
CHECK
VALVES
TO
IMPLEMENT
CONTROL
CHARGE RELIEF
VALVE
VALVE
10 - 6
FIXED
SWASHPLATE
MOTOR
OUTPUT
SHAFT
FIXED DISPLACEMENT
MOTOR
SUCTION FLOW
CHARGE PRESSURE
HIGH PRESSURE
CASE PRESSURE
ATMOSPHERE