Apparatus for controlling a power-assisted steering gear in response to vehicle speed

An apparatus for helping to turn steerable wheels of a vehicle, the apparatus comprising:

• a hydraulic power-assisted steering gear;
• an electric motor for actuating the steering gear;
• a pump for supplying the steering gear with hydraulic fluid;
• at least one valve assembly interposed between the pump and the steering gear;
• a vehicle speed sensor for sensing vehicle speed and for providing a vehicle speed signal;
• and
• a controller responsive to the vehicle speed signal, the controller actuating the at least one valve assembly to selectively place the pump in fluid communication with the steering gear to provide hydraulic fluid to the steering gear when the vehicle speed signal indicates a vehicle speed below a predetermined value and the controller actuating the at least one valve assembly to selectively place the pump out of fluid communication with the steering gear when the vehicle speed signal indicates a vehicle speed above the predetermined value.