Patent ID: 6196641
Filing Date: 2001-03-06
Classification: B60T

Abstract:
A fluid pressure boosting device comprising:a fluid pressure source for producing fluid pressure;a reservoir for storing fluid;a power piston having a pressure receiving surface and producing an output;a power chamber confronting the pressure receiving surface of said power piston;a control valve communicating with the fluid pressure source and the reservoir, said control valve, in its inoperative state, shutting off said power chamber from said fluid pressure source and connecting said power chamber to said reservoir, and in its operative state, shutting off said power chamber from said reservoir and connecting said power chamber to said fluid pressure source to introduce pressured fluid in said fluid pressure source into said power chamber corresponding to its operation;an input shaft for controlling an operation of said control valve, having a step on the outer periphery thereof; anda reaction chamber formed around a part of the input shaft so that the step of said input shaft is positioned in the reaction chamber, a pressurized fluid at a servo-ratio control pressure being introduced into said reaction chamber to act on the step of the input shaft to thereby control a servo ratio.