Hydraulic Flow Diagrams - Toro Multi Pro 1200 Service Manual

Hydraulic Flow Diagrams

Steering Circuit
A single section, belt driven gear pump supplies hydrau-
lic flow to the steering control valve and steering cylin-
der. The gear pump takes its suction from the transaxle.
Steering circuit pressure is limited to 1000 PSI (69 bar)
by a relief valve located in the gear pump.
Hydraulic flow and pressure to the steering control valve
can be monitored at the outlet of the gear pump.
With the steering wheel in the neutral position and the
engine running, flow enters the steering control valve
and goes through the steering control spool valve, by--
passing the rotary meter (V1) and steering cylinder.
Flow leaves the control valve, to the oil filter and returns
to the transaxle.
Left Turn
When a left turn is made with the engine running, the
turning of the steering wheel positions the spool valve so
that flow goes through the top of the spool. Flow entering
the steering control valve from the pump goes through
the spool, to the rotary meter (V1) and out the L port.
Pressure contracts the steering cylinder piston for a left
turn. The rotary meter ensures that the oil flow to the cyl-
STEERING CYLINDER
NO PISTON MOVEMENT
R L
T P
STEERING
CONTROL
NEUTRAL POSITION
Multi Pro 1200/1250
inder is proportional to the amount of the turning on the
steering wheel. Fluid leaving the cylinder flows back
through the steering control spool valve, then to the oil
filter and returns to the transaxle.
The steering control valve returns to the neutral position
when turning is completed.
Right Turn
When a right turn is made with the engine running, the
turning of the steering wheel positions the spool valve so
that flow goes through the bottom of the spool. Flow en-
tering the steering control valve from the pump goes
through the spool, to the rotary meter (V1) and out the
R port. Pressure extends the steering cylinder piston for
a right turn. The rotary meter ensures that the oil flow to
the cylinder is proportional to the amount of the turning
on the steering wheel. Fluid leaving the cylinder flows
back through the steering control spool valve, then to
the oil filter and returns to the transaxle.
The steering control valve returns to the neutral position
when turning is completed.
STEERING CYLINDER
PISTON MOVEMENT
L
R
T P
STEERING
CONTROL
LEFT TURN
Figure 8
Page 4 - - 9
STEERING CYLINDER
PISTON MOVEMENT
L
R
T
P
STEERING
CONTROL
RIGHT TURN
Hydraulic System