Hydraulic steering servo, for vehicle, with variable reaction force - has flow control by=pass channel to regulate flow-rate and control reaction force to steering.

摘要

The servo steering system has a servo pump (10) linked to a servo unit (3) via a flow restriction (12) and a control valve in the steering unit. The flow restriction is bridged by a bypass channel (51) with a flow control valve (15) and a spring loaded pressure control valve (2) and a sump (18). The sump is fed via a solenoid valve with the valve opening related to the vehicle speed etc.. This controls the fluid pressure w.r.t. vehicle speed and hence the steering reaction. The fluid is ducted to the sump when the steering force is low and is blocked for higher pressures. ADVANTAGE - Simplified servo action, less fluid waste, improved steering reaction.