Patent ID: 7311033
Filing Date: 2007-12-25
Classification: B62D

Abstract:
1. A hydraulic power steering system for motor vehicles, comprising: a hydraulic servo-valve device; a retroactive device, wherein said retroactive device comprises means for hydraulically producing a restoring moment into a central position, which produces the restoring moment as a function of the pressure differential between a pressure side and a low-pressure side; a hydraulic power-steering pump, wherein said hydraulic power-steering pump supplies the servo-valve device via a first hydraulic line and supplies the retroactive device via a second hydraulic line, and wherein said system further comprises at least one valve means that, when pressure is applied in the central position of the servo-valve, is adapted to produce a pressure differential between an external chamber and an internal chamber of said valve means, wherein said at least one valve means is a pressure regulating valve that is disposed in series with the servo-valve device in the first hydraulic line, and wherein a pressure control valve and a proportional valve are disposed hydraulically in series with the retroactive device in the second hydraulic line.