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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,
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
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
The steering control valve returns to the neutral position when turning is completed.
Hydraulic System
STEERING CYLINDER | STEERING CYLINDER | STEERING CYLINDER | |||||||||
NO PISTON MOVEMENT | PISTON MOVEMENT | PISTON MOVEMENT | |||||||||
| R |
| L |
| R | L |
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| R |
| L |
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| 1350 |
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| 1350 |
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| 1350 |
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| PSI |
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| PSI |
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| PSI |
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T | PB | P | STEERING | T | PB | P | STEERING | T | PB | P | STEERING |
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| CONTROL |
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| CONTROL |
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| CONTROL |
NEUTRAL POSITION | LEFT TURN |
| RIGHT TURN |
Figure 13
Groundsmaster | Page 4 | Hydraulic System |