Toro Greensmaster TriFlex 3400 - Right and Left Turn

Greensmaster 3300/3400 Hydraulic SystemPage 5 -- 21
Right and Left Turn
The tandem gear pump is directly c oupled to the piston
(traction) pump. The rear gear pump section supplies
hydraulic flow for the steering circuit (priority flow), for
raisingandloweringthecuttingunitsandforthetraction
chargecircuit. Thegearpumptakesits suctionfromthe
hydraulic reservoir. Maximum circuit pressure of 1160
PSI (80 bar) is limited by the relief valve located in the
power steering valve.
With the steering wheel in the neutral position ( not
turned) and the engine running, the power steering
valvespoolisinthecenterposition.Gearpumpflowen-
ters the power steering valve at port (P) and goes
through the spool valve, by--passing the steering cylin-
der. Flow leaves the steering valve from port ( E) to be
availablefortheraise/lowerandtractionchargecircuits.
Right Turn
When a right turn is made with the engine running, the
turning of the steering wheel positions the power steer-
ingvalvespoolsothatgear pumpflowgoesthroughthe
top ofthe spool.Flowentering thepower steeringvalve
at port (P) goes through the spool and is routed to two
places. First, most of the flow through the valve is by--
passedoutport(E)andbecomesavailablefortheraise/
lower and traction charge circuits. Second, the
remainder of the flow is drawn through the steering
valverotarymeterandoutsteeringvalveport (R).Pres-
sure retracts the steering cylinder for a right turn. The
rotary meter ensures that the oil flow to the cylinder is
proportionaltotheamountofthe turningonthesteering
wheel.Fluid leaving thecylinder flowsbackthrough the
spool valve, out steering valve port (T) and then to the
traction charge circuit.
The powersteeringvalve returns totheneutral position
when turning is complete.
Left Turn
When a left turn is made with the engine running, the
turning of the steering wheel positions the power steer-
ingvalvespoolsothatgear pumpflowgoesthroughthe
bottom of the spool. Flow entering the power steering
valveatport(P)goes throughthe spoolandis routedto
two places. First, most of the flow through the valve is
by--passed out port (E) and becomes available for the
raise/lowerand tractioncharge circuits.Second,the re-
mainder of the flow is drawn through the steering v alve
rotary meter and out steering valve port (L). Pressure
extends the steering cylinder for a left turn. The rotary
meter ensures that the oil flow to the cylinder is propor-
tionaltotheamountoftheturningonthesteeringwheel.
Fluid leaving the cylinder flows back through the spool
valve,outsteeringvalve port(T) andthentothetraction
charge circuit.
The powersteeringvalve returns totheneutral position
when turning is complete.
Figure 10
v
P
TE
PORT BALL
LR
JOINT END
STEERING CYLINDER
1160
VALVE
PSI
POWER
STEERING
4.5
NEUTRAL POSITION
RIGHT TURN
LEFT TURN
NO CYLINDER
MOVEMENT
TO LIFT CONTROL
TO CHARGE
CIRCUIT
VALVE
FROM GEAR
PUMP
P
TE
PORT BALL
LR
JOINT END
STEERING CYLINDER
1160
VALVE
PSI
POWER
STEERING
4.5
TO LIFT CONTROL
TO CHARGE
CIRCUIT
VALVE
FROM GEAR
PUMP
PORT BALL
LR
JOINT END
STEERING CYLINDER
P
TE
1160
VALVE
PSI
POWER
STEERING
4.5
TO LIFT CONTROL
TO CHARGE
CIRCUIT
VALVE
FROM GEAR
PUMP
Hydraulic
System