1. Mechanical Transmission Principles
Rack-and-Pinion Type
A gear on the steering shaft meshes with a rack; rotational motion is directly converted into linear motion of the tie rods. This design is simple and reliable.
Recirculating Ball Type
A screw shaft drives a nut filled with steel balls; a two-stage speed reduction is achieved through a rack-and-sector gear mechanism, resulting in high transmission efficiency.
Worm-and-Finger Pin Type
A crank-mounted finger pin travels along the helical groove of a worm shaft, driving the rocker arm shaft to rotate. This design was relatively common in early engineering vehicles.
2. Power Assist System Principles
Hydraulic Power Assist
An engine-driven oil pump generates high-pressure fluid (10 MPa). A control valve distributes this fluid to a power cylinder based on steering demand, and a push-rod mechanism provides the auxiliary torque.
Electric Power Assist (EPS)
A torque sensor detects input from the steering wheel. An electric motor applies auxiliary force via a worm-and-worm wheel reduction mechanism, and the level of assistance can be dynamically adjusted based on vehicle speed.
