FLUID ASSISTING DEVICE

摘要

Hydraulic assistance device, incorporating a casing (10) provided with a bore (12) in which first piston means (16, 18) is slideably mounted, the piston (16, 18) being able to move under the effect of the actuation of a brake pedal between a first position allowing communication between a first chamber (72) which is connected to a braking circuit (70) and a low pressure reservoir (40), and isolating this chamber (72) from a source of high pressure fluid (76), and a second position isolating the chamber (72) from the low pressure reservoir (40) and causing it to communicate with the high pressure source (76), the device also incorporating a second chamber (38) formed in the casing (10), the communication between the first chamber (72) and the reservoir (40) incorporating a second bore (52) in which a control piston (54) of second piston means (54, 60) is slideably mounted, incorporating a bore (56), the first piston having a bore in which a plunger (31) is slideably mounted, the plunger (31) joining the first piston means to the second piston means (54, 60), and a valve (62) which is capable of closing the communication between the first chamber (72) and the reservoir (40) under the effect of the movement of the first piston, characterized in that the first chamber (72) is isolated from the second chamber (38) by a seal (86) which is slideably mounted in the bore (12) and is capable of being moved by the first piston means (16, 18) when the hydraulic pressures in the first and second chambers are essentially equal.