From worm gear to rack-and-pinion, from hydraulic assistance to electronically controlled systems: the steering technologies used in modern cars.
Power assistance first appeared in heavy machinery in the late 1930s using simple pneumatic systems, and reached passenger cars in 1951. A steering mechanism transmits and multiplies the driver’s input and returns the wheel to centre on its own.
Worm-gear steering is heavy and gives poor feedback, so it is no longer used in modern cars. Rack-and-pinion, the most common type, is light, inexpensive and compact, and offers precise steering, especially in front-wheel-drive cars.
Because a hydraulic pump constantly moves fluid and wastes fuel, designers have turned to electronically controlled systems. The article also explains how these newer solutions work.