Truck power steering systems

The complete power steering system is a complex combination of hydraulics, gears and linkages which must provide sufficient power to steer a loaded heavy duty truck axle lock to lock whilst the vehicle is stationary with a minimum of input effort and yet provide a degree of feel to the driver. The power steering gear, although it is probably the most identifiable part of the system is only part of a complete system which must work in harmony if satisfactory performance is to be achieved. The system of road wheels, front end geometry, linkage, steering gear and hydraulics can be subject to very high dynamic loads generated by road shocks or self sustaining oscillations such as wheel shimmy and wheel wobble. The paper outlines installation requirements of integrated power steering gears and front axle alignment factors which affect the steering gear's performance.