Steering Gear, Design

Courtesy of VOLVO CARS CORPORATION

The description covers the steering gear in the left-hand drive version. The gear in the right-hand version is a mirror image of the left-hand version. There is also a speed dependent steering gear, for further information, see Design and Function, Central electronic module (CEM).

The steering gear is the rack and pinion type with the mechanical and servo assisted elements combined in one module.

The mechanical element consists of the gear drive (8), steering rack (12) and track rods (14).

The gear drive is carried by a journal bearing (7) and a roller bearing (10) in the steering gear housing.

The steering rack is carried by a journal bearing on the right end and in the housing is guided by the gear drive (8) and the sprung actuation piston (9).

A cylinder pipe (13) is secured to the steering gear housing (11). This pipe operates as the servo element's working cylinder for the hydraulic piston on the steering rack.

Regulation of the oil flow to the hydraulic cylinder occurs in the valve housing, which is integrated into the steering gear housing.

Valve section 

The gear drive is driven by the steering gear input shaft (1) which has exterior lugs. There is radial play between the lugs.

A torsion bar (2) which joins the input shaft to the gear drive holds the lugs in a position where the play is equal on each side when there is no steering input on the shaft.

A torsion bar is pressed into the gear drive. The gear drive is fastened to the input shaft with a pressed in lock pin.

A valve spool (5) is located in the valve housing and fixed to the gear drive with a lock pin. The valve operating range is radial between four thin vertical grooves in the valve spool and four cut-outs in the input shaft.

The valve is balanced as a complete unit and cannot be rebalanced.