Simplicity AGCO Allis 2000 Series, Service & Repair Manual

Page: 144 / 312

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.
10 U-Type Hydrostatic Unit Service
System Description
10 - 6
Figure 6. Neutral
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.
Figure 7. Reverse
Figure 8. Circuit Flow Diagram
MOTOR
OUTPUT
SHAFT
FIXED DISPLACEMENT
MOTOR
IMPLEMENT
RELIEF VALVE
FROM IMPLEMENT
CONTROL VALVE
CYLINDER BLOCK
ASSEMBLY
CHARGE RELIEF
VALVE
TO
IMPLEMENT
CONTROL
VALVE
CYLINDER
BLOCK
ASSEMBLY
FORWARD
NEUTRAL
REVERSE
PUMP
INPUT
SHAFT
VARIABLE
SWASHPLATE
VARIABLE DISPLACEMENT PUMP
CHARGE
PUMP
FILTER
RESERVOIR
SUCTION FLOW
CHARGE PRESSURE
HIGH PRESSURE
CASE PRESSURE
ATMOSPHERE
CHECK
VALVES
FIXED
SWASHPLATE
Not
for
Reproduction