US Patent 6945353 Variable ratio steering gear

A rack (1) and pinion (4) steering gear for a vehicle in which the steering angle ratio varies as a function of at least both the steering wheel angle input by the driver and vehicle speed. The steering gear comprising a rack (1) laterally displacable with respect to a steering gear housing and a pinion (4) laterally movable within the housing substantially in a direction of travel of the rack (1) whilst engaged with the rack (1). The steering angle ratio is increased in a central region of travel of the rack (1) when compared to regions either side thereof, and steering angle ratio is further increased in the central region as vehicle speed increases.