Patent ID: 6431662
Filing Date: 2002-08-13
Classification: B60T

Abstract:
A braking pressure source device provided in a braking system for an automotive vehicle, said braking system including a brake operating member manually operable with a brake operating force applied thereto, said braking pressure source device comprising:a master cylinder including a cylinder housing, a pressurizing piston fluid-tightly and slidably received in said cylinder housing and cooperating with said cylinder housing to define a pressurizing chamber and a back-pressure chamber on a front and a rear side of said pressurizing piston, and an input rod which fluid-tightly and slidably extends through a rear end wall of said cylinder housing, said pressurizing piston being advanced by said brake operating force of said brake operating member transmitted thereto through said input rod, to pressurize a working fluid in said pressurizing chamber; means for defining a communication passage for communication between said pressurizing chamber and said back-pressure chamber; a first control valve device disposed in said communication passage for controlling the communication between said pressurizing and back-pressure chambers through said communication passage; and a first control valve control device for controlling said first control valve device, and wherein said first control valve control device controls said first control valve device on the basis of at least one of an operating state of said brake operating member, a running state of said automotive vehicle and a state of a road surface on which said automotive vehicle is running.