HYDRAULIC REDUCTION GEAR RATIO ADJUSTABLE POWER STEERING SYSTEM

摘要

PROBLEM TO BE SOLVED: To provide a hydraulic reduction gear ratio adjustable power steering system attaining both a steering wheel operation touch felt by a driver and an energy saving effect.

SOLUTION: This hydraulic reduction gear ratio adjustable power steering system 1 comprises a variable transmission ratio mechanism 7 having a driving motor, a flow rate control valve 41 for controlling a discharged flow rate of a hydraulic pump 10 for circulating work fluid, and a steering angle sensor 310 for measuring a steering wheel steering angle inputted to a steering wheel 31. A valve controlling controller 50 is so constituted that it takes a measured ACT angle that is a rotating angle of a driving motor 70 and calculates a target ACT angle of the driving motor 70 in response to the steering wheel steering angle. Further, the valve controlling controller 50 controls the flow rate control valve 41 in such a way that the discharging flow rate may exceed a predetermined flow rate when a value of a deviated ACT angle acting as a deviation between the target ACT angle and the measured ACT angle is more than a threshold value.

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