The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 15, 2001
Filed:
Oct. 25, 1999
Dieter Elser, Essingen, DE;
Andreas Braun, Schwäbisch Gmünd, DE;
Wolfgang Zeitz, Schwäbisch Gmünd, DE;
Zf Friedrichshafen AG, Friedrichshafen, DE;
Abstract
In connection with a servo-assisted steering system with hydraulic servo-assistance for motor vehicles, a steering shaft (,), which is provided with a steering wheel (,), is connected via a torsion spring (,) with an input member of a steering gear (,). An output member of the steering gear (,) is connected with the wheels (,) of the vehicle which are to be steered. In case of a relative rotation of the steering shaft (,) in respect to the input member, two work chambers (,) of a servo motor of a force amplification device can be pressurized by a servo pump via a steering valve with a pressure medium. Two sensors (,) for detecting a rotation angle and/or a torque are arranged on the steering shaft (,), or respectively on the output member of the steering gear (,). After the steering wheel (,) is released following a steering process, the wheels to be steered (,) and the steering gear (,) can be returned with hydraulic assistance. The amount and the direction of the hydraulic servo-assistance, as well as the return of the wheels (,) to be steered, are controlled by means of a common electronically-controlled electromagnetic (,) valve.