Power Steering Hydraulic Operation
| Item Number | Description |
|---|---|
| 1 | Reservoir |
| 2 | Cooler |
| 3 | Valve unit |
| 4 | Steering rack and pinion |
| 5 | Flow control/pressure relief return |
| 6 | Flow control/Pressure relief valve |
| 7 | Output port |
| 8 | Power steering pump |
| 9 | Low pressure suction line |
When the engine is started the power steering pump draws fluid from the reservoir into the low pressure suction line. The fluid passes through the pump and emerges as pressurized fluid at the outlet port. The attenuated high pressure hose passes the pressurized fluid to the steering gear valve unit.
If no steering effort is applied, there is minimal restriction within the system and the supply pressure from the pump is low. Minimal pressure is applied, via the valve unit, to each side of the piston in the hydraulic cylinder and the full flow from the power steering pump returns to the reservoir via the fluid cooler.
When steering effort is applied in either direction, the return flow of fluid to the reservoir is restricted, causing the supply pressure from the pump to increase. The pressurized fluid is directed to the applicable side of the piston in the hydraulic cylinder, via the valve unit, providing the power assistance required to reduce the steering effort. Fluid displaced from the low pressure side of the cylinder is returned via the valve unit and fluid cooler to the reservoir. The fluid cooler reduces the fluid temperature which prolongs the life of hoses and seals in the system.