
Groundsmaster 4000--D
Hydraulic System
Page 4 -- 23
Steering Circuit
A four section gear pump is coupled to the piston (trac-
tion) pump. The third gear pump section supplies hy-
draulic flow to the steering control valve and the lift/lower
control valve. Pump hydraulic flow is delivered to the two
circuits through a proportional flow divider located in the
fan drive manifold. The gear pump takes its suction from
the hydraulic reservoir. Steering circuit pressure is limit-
ed to 1350 PSI (93 bar) by a relief valve located in the
steering control.
With the steering wheel in the neutral position and the
engine running, flow enters the steering control valve at
the P port and goes through the steering control spool
valve, by--passing the rotary meter (V1) and steering
cylinder. Flow leaves the control valve through the PB
port to the oil filter and traction charge circuit.
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 at the P port goes through the
spool and is routed to two places. First, most of the flow
through the valve is by--passed out the PB port back to
the oil filter and traction charge circuit. Second, the re-
mainder of the flow is drawn through 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 cylinder is proportional to the
amount of the turning on the steering wheel. Fluid leav-
ing the cylinder flows back through the spool valve then
through the T port and to the hydraulic reservoir.
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 at the P port goes
through the spool and is routed to two places. As in a left
turn, most of the flow through the valve is by--passed out
the PB port back to the oil filter and traction charge cir-
cuit. Also like a left turn, the remainder of the flow is
drawn through rotary meter (V1) but goes out port R.
Pressure extends the steering cylinder piston for a right
turn. The rotary meter ensures that the oil flow to the cyl-
inder is proportional to the amount of the turning on the
steering wheel. Fluid leaving the cylinder flows back
through the spool valve then through the T port and to
the hydraulic reservoir.
The steering control valve returns to the neutral position
when turning is completed.
Figure 13
1350
PSI
PB
STEERING
T
R
P
L
PISTON MOVEMENT
CONTROL
1350
PSI
PB
STEERING CYLINDER
STEERING
T
R
P
L
PISTON MOVEMENT
CONTROL
1350
PSI
PB
STEERING CYLINDER
STEERING
T
R
P
L
CONTROL
LEFT TURN
NEUTRAL POSITION
RIGHT TURN
NO PISTON MOVEMENT
STEERING CYLINDER
Hydraulic System
Summary of Contents for Groundsmaster 4000-D
Page 2: ...Groundsmaster 4000 D This page is intentionally blank ...
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Page 10: ...Groundsmaster 4000 D Page 1 6 Safety This page is intentionally blank ...
Page 34: ...Groundsmaster 4000 D Page 3 18 Kubota Diesel Engine This page is intentionally blank ...
Page 212: ...Groundsmaster 4000 D Page 5 38 Electrical System This page is intentionally blank ...
Page 253: ...Groundsmaster 4000 D Page 7 11 Chassis This page is intentionally blank Chassis ...
Page 264: ...Groundsmaster 4000 D Page 7 22 Chassis This page is intentionally blank ...
Page 269: ...Groundsmaster 4000 D Cutting Decks Page 8 5 This page is intentionally blank Cutting Decks ...
Page 282: ...Groundsmaster 4000 D Foldout Drawings Page 9 2 This page is intentionally blank ...
Page 292: ...Page 9 12 Groundsmaster 4000 D Engine Wire Harness STARTER STARTER STARTER ...
Page 294: ...Page 9 14 Groundsmaster 4000 D Front Wire Harness FLOW DIVIDER SOLENOID ...