Rack-and-pinion steering gear, function - GF46.20-P-1000-01T

Model 211 

The drive pinion (4b) transmits the movement of the steering wheel to the gear rack (7) and then via the tie rods to the wheels.

The drive pinion has spiral splines. Because a number of teeth are always meshed at the same time, the rack-and-pinion steering is resistant to wear and has a very low noise level.

Fig 1: Identifying Drive Rack And Gear Rack

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Steering gear ratio and gear teeth 

The variable steering gear ratio is achieved by means of the effective diameters (d1 and d2) resulting from the shape and angles of the gear teeth.

In the central area (X) the gear rack is indirect. The rack-and-pinion steering becomes increasingly direct in the outside areas (Y).

Fig 2: Identifying Gear Teeth Outside And Central Areas

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

The difference between the gear ratio in the central area (X) and the gear ratio in the outside area (Y) amounts to approx. 15%.

Fig 3: Identifying Gear Central Area And Outside Area

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.