Servo-assisted hydrostatic steering system - has changeover switch to select fluid supply from pumps driven by engine and wheels respectively

摘要

The servo assisted, hydrostatic steering system is operated by two pumps, with one pump (16a) driven off the engine (18) and the second pump (16) driven directly off a wheel. A changeover switch (22) selects the output from either pump depending on the driving conditions so that servo force is always available. The servo pressure is taken from the wheel driven pump above a set road speed, while the larger servo force, which is required for parking etc. is drawn from the engine driven pump.