Fail=safe vehicle rear wheel steering - has spring driven centering control and fluid coupling for steering torque

摘要

The rear wheel track rod (2) is driven by an electric servo motor (12) and a reduction gearing (13). A fluid clutch (15, 16) couples the reduction gearing to the drive pinion (18) which engages the track on the track rod. If the drive motor speed reduces below a set level a spring driven centering control (3) becomes operative. The centering control has a piston (4) balanced between two opposing springs (5, 6). A spring driven ratchet stop (8) locks the steering in the ahead position, and is only lifted when parking steering, at low speeds, is required. ADVANTAGE - Failsafe self centering control, simple clutch action with torque controlled by motor speed.