caution - Toro
caution - Toro
caution - Toro
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Steering Circuit<br />
A four section gear pump is coupled to the piston (traction)<br />
pump. The third gear pump section supplies hydraulic<br />
flow to the steering control valve and the lift/lower<br />
control valve. Pump hydraulic flow is delivered to the two<br />
circuits through a proportional flow divider located in the<br />
fan drive manifold. The gear pump takes its suction from<br />
the hydraulic reservoir. Steering circuit pressure is limited<br />
to 1350 PSI (93 bar) by a relief valve located in the<br />
steering control.<br />
With the steering wheel in the neutral position and the<br />
engine running, flow enters the steering control valve at<br />
the P port and goes through the steering control spool<br />
valve, by--passing the rotary meter (V1) and steering<br />
cylinder. Flow leaves the control valve through the PB<br />
port to the oil filter and traction charge circuit.<br />
Left Turn<br />
When a left turn is made with the engine running, the<br />
turning of the steering wheel positions the spool valve so<br />
that flow goes through the top of the spool. Flow entering<br />
the steering control valve at the P port goes through the<br />
spool and is routed to two places. First, most of the flow<br />
through the valve is by--passed out the PB port back to<br />
the oil filter and traction charge circuit. Second, the remainder<br />
of the flow is drawn through the rotary meter<br />
(V1) and out the L port. Pressure contracts the steering<br />
cylinder piston for a left turn. The rotary meter ensures<br />
that the oil flow to the cylinder is proportional to the<br />
amount of the turning on the steering wheel. Fluid leaving<br />
the cylinder flows back through the spool valve then<br />
through the T port and to the hydraulic reservoir.<br />
The steering control valve returns to the neutral position<br />
when turning is completed.<br />
Right Turn<br />
When a right turn is made with the engine running, the<br />
turning of the steering wheel positions the spool valve so<br />
that flow goes through the bottom of the spool. Flow entering<br />
the steering control valve at the P port goes<br />
through the spool and is routed to two places. As in a left<br />
turn, most of the flow through the valve is by--passed out<br />
the PB port back to the oil filter and traction charge circuit.<br />
Also like a left turn, the remainder of the flow is<br />
drawn through rotary meter (V1) but goes out port R.<br />
Pressure extends the steering cylinder piston for a right<br />
turn. The rotary meter ensures that the oil flow to the cylinder<br />
is proportional to the amount of the turning on the<br />
steering wheel. Fluid leaving the cylinder flows back<br />
through the spool valve then through the T port and to<br />
the hydraulic reservoir.<br />
The steering control valve returns to the neutral position<br />
when turning is completed.<br />
Hydraulic<br />
System<br />
STEERING CYLINDER<br />
NO PISTON MOVEMENT<br />
STEERING CYLINDER<br />
PISTON MOVEMENT<br />
STEERING CYLINDER<br />
PISTON MOVEMENT<br />
R<br />
L<br />
R<br />
L<br />
R<br />
L<br />
1350<br />
PSI<br />
1350<br />
PSI<br />
1350<br />
PSI<br />
T<br />
PB<br />
P<br />
STEERING<br />
CONTROL<br />
T<br />
PB<br />
P<br />
STEERING<br />
CONTROL<br />
T<br />
PB<br />
P<br />
STEERING<br />
CONTROL<br />
NEUTRAL POSITION<br />
LEFT TURN<br />
RIGHT TURN<br />
Figure 13<br />
Groundsmaster 4100--D<br />
Page 4 - 23<br />
Hydraulic System