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| Illustration 1 | g00707012 |
(1) Flow divider spool (2) Spring (3) Relief valve (4) Valve body (5) Gears | |
The gear pump is a fixed displacement pump that is mounted to the accessory drive on the engine. The gear pump supplies oil to the steering circuit and the leveling blade circuit (if equipped). The gear pump also provides charge oil for the propel circuit and the vibratory circuit. Flow divider spool (1) divides the flow between the steering circuit and the charge circuit. The steering circuit has priority, and the return flow from the steering circuit returns into the charge circuit.
When the machine is running, output oil from pump gears (5) enters valve body (4). The oil flows through internal passages into the center of flow divider spool (1). The oil is directed into the steering circuit.
Pressure that is acting on the flow divider spool creates a force on the spool. When the pressure is high enough, the spool movesand the spool compresses spring (2). This allows oil to flow through internal passages into the charge circuit.
The flow divider acts as a priority valve when the steering system is operated. Pilot signal oil acts against the upper end of the priority valve in addition to the force of the spring. The increased force moves the spool and oil is directed into the steering circuit.
The pilot signal oil also acts against relief valve (3). The relief valve empties into the pump inlet. The relief valve serves as the pressure relief for the steering cylinders.