Patent ID: 6779496
Filing Date: 2004-08-24
Classification: F01L,Y10T

Abstract:
A pressure reservoir (62) for exerting pressure on a hydraulic system (10), the pressure reservoir comprising,a housing (64, 68) a piston (72), and prestressing means (88, 90), prestressing the piston (72) of the pressure reservoir (62) during operation, the prestressing means having a characteristic force-travel curve, in one range of motion of the piston (72), that has a slope which differs from the slope in a different range of motion of the piston (72), said prestressing means (88, 90) having at least two series-connected devices (88, 90), which have characteristic force-travel curves of different slope and which prestress the piston (72) in operation, said at least two series-connected devices (88, 90) comprising at least two series-connected springs and where the stiffness of at least one spring (88) differs from that of at least one other spring (90), wherein the pressure reservoir (62) further comprises an elongated part (80) with two end portions (82, 84) and one support portion (86), which is disposed between the end portions (82, 84) and has a larger outer dimension than the end portions (82, 84) and on which two adjacent springs (88, 90) are braced, the at least one spring (88) being tightened in operation between one side of the support portion (86) and the piston (72), and the at least one other spring (90) being tightened between the other side of the support portion (86) and a housing portion (68).