Patent ID: 6655140
Filing Date: 2003-12-02
Classification: B60T

Abstract:
A fluid pressure boosting device, for boosting an input by fluid pressure to output the boosted pressure, comprising at least a power chamber to which hydraulic fluid from a fluid pressure source is supplied during operation, a power piston which is actuated by fluid pressure of said power chamber to output, a control valve which is arranged inside said power piston to control the supply and discharge of the hydraulic fluid of said power chamber, and an input shaft for operating said control valve according to the input, said fluid pressure boosting device being characterized in thatsaid control valve comprises a supply valve which stops the supply of hydraulic fluid from said fluid pressure source to said power chamber in the inoperative state and allows the supply of hydraulic fluid from said fluid pressure source to said power chamber according to said input in the operative state, and a discharge valve which allows the discharge of hydraulic fluid of said power chamber in the inoperative state and stops the discharge of hydraulic fluid of said power chamber in the operative state, wherein said supply valve has an annular poppet valve element supported by a cylindrical supply valve member which is slidably arranged in said power piston and a supply valve seat which is arranged in said power piston and in which said poppet valve element can be seated, and said discharge valve has an annular poppet valve element supported by a cylindrical discharge valve member disposed integrally with said supply valve member and a discharge valve seat which is disposed to move together with said input shaft and to which the latter poppet valve element can be seated, and that said input shaft extends to penetrate said supply valve and said discharge valve in the axial direction and is arranged such that, in the inoperative state, an end of said input shaft confronts the reaction disk arranged in an output-side member with a predetermined space therebetween and, in the operative state and when producing a predetermined output, the end of said input shaft comes in contact with said reaction disk so that a reaction force is transmitted from said reaction disk to said input shaft.