Steering columns

Steering columns, Rack-and-pinion gearbox, Helix, Variable ratio steering, Worm gearbox, Power steering, steering process, Flow-control valve, Electric power assisted steering, Basic electric power steering operation.

Steering columns

All power steering pumps have a flow-control valve to vary fluid flow and power steering system pressures. A pressure relief valve prevents excessive pressures developing when the steering is on full-lock, and held against its stops. The flow control valve is located at the outlet fitting of the pump.
During slow cornering, or when parking, pump speeds are normally low. There is less demand for fluid flow, but to provide the required assistance, high pressure is needed. Discharge ports direct the fluid to the outlet, and then to the steering gear. The outlet fluid pressure is slightly lower than the internal high pressure coming from the pump.