Steering gear, rack-and-pinion steering, function - GF46.20-P-1000-01A

The steering wheel movement is transmitted to the rack (7) by the drive pinion (4b) and then to the wheels via the tie rods.

The drive pinion has a spiral-shaped toothing. As an increasing number of teeth mesh at the same time the rack-and-pinion steering is wear-resistant and has a very low noise level.

Fig 1: Identifying Drive Rack-And-Pinion

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Steering gear ratio and toothing 

The variable steering gear ratio is achieved by the effective diameters (d1 and d2) which result from the shape and angles of the toothing.

The rack is designed indirect in the center area (X). The rack-and-pinion steering becomes increasingly more direct in the outer areas (Y).

Fig 2: Identifying Steering Gear Ratio Shape And Angles Of Toothing

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

The difference between the ratio in the center area (X) and the ratio in the outer area (Y) is:

• approx. 27 % for standard steering
• approx. 17 % for sports suspension
  Fig 3: Identifying Difference Between Ratio In Center Area And Ratio In Outer Area

  Courtesy of MERCEDES-BENZ OF NORTH AMERICA.