Ford Global Technolgoies, LLC

Michael J Gabel

Stephen Think Hung

John Francis Laidlaw

Michael J Kostrzewa

The present invention provides a power assist steering system for use with a motor vehicle utilizing a torque sensor and an electronically controlled hydraulic valve used to supply or meter hydraulic fluid to a hydraulic cylinder that provides power assist to the steering system. The torque sensor measures driver input and provides a signal to the controller that controls an electrically actuated hydraulic valve. Additionally, steering wheel rotational speed and position are also input to the controller wherein the controller generates a steering assist command that minimizes the magnitude of difference, or error, between the steering torque reference value determined from the steering wheel speed and position and the measured torque. By doing so, the invention controls steering wheel feel, as opposed to the conventional practice of controlling the steering assist boost curve.

Power assist steering system

A steering mechanism is provided, including a rack, a rotatable support member, and an automatically-adjustable support member. The rack includes a rack gear portion and the pinion includes a pinion gear portion coupled with the rack gear portion. The rotatable support member is positioned with respect to the rack or the pinion such that rotation of the rotatable support member adjusts an overlap distance between the rack gear portion and the pinion gear portion. The automatically-adjustable support member automatically urges together the rack and the pinion along an urging direction. The urging direction remains substantially constant throughout the rotation of the rotatable support member within a desired angular range.

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Huntington Woods, MI, United States of America

Michael J Gabel