Greensmaster 3150 Hydraulic SystemPage 4 -- 17
Right and Left Turn
The tandem gear pump is directly coupled to the piston
(traction) pump. The rear gear pump section supplies
hydraulic flow for the steering circuit (priority flow), for
raisingandlowering thecutting unitsandfor thetraction
charge circuit. Thegear pumptakes its suctionfrom the
hydraulic reservoir. Maximum circuit pressure of 1160
PSI (80 bar) is limited by the relief valve located in the
steering valve.
With the steering wheel in the neutral position and the
engine running, the spool valve in the steering valve is
in the center position. Flow enters the steering control
valve at Port (P) and goes through the spool valve, by--
passing the steering cylinder. Flow leaves the control
valve out port (E) tobeavailable for the raise/lowerand
traction charge circuits.
Right Turn
When a right turn is made with the engine running, the
turningofthesteeringwheelpositionsthe spoolvalvein
the steering valve so that flow goes through the bottom
of the spool. Flow entering thesteering valveat Port(P)
goesthroughthespoolandisroutedtotwoplaces.First,
most of the flow through the valve is by--passed out
steering valve port (E) and is available for raising and
loweringthe cuttingunits andfor thetraction chargecir-
cuit.Second,theremainderofthe flowis drawnthrough
the steering valve rotary meter and out steering valve
port (R). Pressuremoves the steering cylinder pistonto
extend thecylinder for a rightturn. The rotary meteren-
suresthattheoilflowtothecylinderisproportionaltothe
amount of turning on the steering wheel. Fluid leaving
the cylinderflows backthrough the spoolvalve thenout
steering valve port (T) and then to the traction charge
circuit.
The steering valve returns to the neutral position when
turning is complete.
Left Turn
When a left t urn is made with the engine running, the
turningofthesteeringwheelp ositionsthe spoolvalvein
the steering valve so that flow goes through the top of
the spool (Fig. 10). Flow entering the steering valve at
Port (P) goes through the spool and is routed to two
places. First, most of the flow through the valve is by--
passed out steering valve port(E)andisavailablefor
raisingandloweringthecuttingunitsandforthetraction
charge circuit. Second, the remainder of the flow is
drawn through the steering valve rotary meter and out
steeringvalveport(L).Pressuremovesthesteeringcyl-
inder piston to retract the c ylinder for a left turn. The
rotary meter ensures that the oil flow to the cylinder is
proportional to the amount of turning on the steering
wheel. Fluid leaving the cylinder flows backthrough the
spool valve then out steering valve port (T) and then to
thetractionchargecircuit.
The steering valve returns to the neutral position when
turning is complete.
Figure 10
4.5
1160 PSI
Steering Cylinder
1.5” Bore
0.75” Rod
6.19” Stroke
PET
LR
STEERING
VALVE
From Gear Pump
Port ST
To Manifold
Port P2
To Manifold
Hydraulic
System
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