Patent ID: 6347842
Filing Date: 2002-02-19
Classification: B60T

Abstract:
A braking hydraulic pressure source apparatus comprising:a cylinder housing having an open end; an input member operable to receive an input force based on an operation of a brake operating member; a pressurizing piston fluid-tightly and slidably received within said cylinder housing and cooperating with said cylinder housing to define a front pressurizing chamber and a rear assisting pressure chamber on respective front and rear sides of said pressurizing piston, and said pressurizing piston being advanced by said input force received from said input member in response to said operation of said brake operating member, to pressurize a working fluid in said front pressurizing chamber; a closure member fluid-tightly closing said open end of said cylinder housing and cooperating with said cylinder housing and said pressurizing piston to define said rear assisting pressure chamber, said input member fluid-tightly and slidably extending through said closure member such that said input force is applicable directly to said pressurizing piston rather than via said working fluid in said rear assisting pressure chamber, irrespective of an amount of said input force; and an electrically controlled assisting pressure control device for controlling an assisting hydraulic pressure which is a pressure of the working fluid in said rear assisting pressure chamber, such that a boosting ratio which is a ratio of an output of said pressurizing piston on an input of said pressurizing piston is controlled to be a predetermined value.