Patent ID: 6775979
Filing Date: 2004-08-17
Classification: B60T

Abstract:
Actuation device for an electrohydraulic brake system of the â€˜brake-by-wireâ€™ type comprising:a first piston that is operable by means of an actuating pedal and biassed by a first resetting spring, a second piston biassed by a second resetting spring, the said pistons being arranged one behind the other in a housing and limiting pressure chambers that are in connection with an unpressurized pressure fluid supply reservoir, hydraulic lines closable by means of a first and a second valve device being connected to the pressure chambers, with at least the first resetting spring being designed as a travel simulator spring that determines the pedal characteristics, a sealing sleeve which is arranged at the second piston and limits the first pressure chamber that is assigned to the first piston, and a third valve device which closes or opens a hydraulic connection between the first pressure chamber and the pressure fluid supply reservoir, wherein the third valve device is adapted to be closed by the movement of the second piston in relation to the housing, and is formed by the sealing sleeve and a channel that is designed in the area of movement of the sealing sleeve and connected to the pressure fluid supply reservoir.