Patent attributes
A hydraulic brake apparatus includes a tandem brake master cylinder having a rod piston moving in response to a brake pedal, and a floating piston moving in response to the rod piston; a separation valve provided in a hydraulic brake circuit connecting the brake master cylinder and brake wheel cylinders in order to establish and shut off communication between the brake master cylinder and the brake wheel cylinders; a pressure control valve unit for controlling fluid pressure to be supplied from an external fluid-pressure supply source to the brake wheel cylinders while the separation valve is in a shutoff condition; and a stroke simulator mechanism for allowing an idle stroke of the rod piston and an idle stroke of the floating piston while the separation valve is in the shutoff condition. The idle stroke of the floating piston starts during the idle stroke of the rod piston.