Disc braking device with automatic boost

摘要

A braking device for an automotive vehicle having a master cylinder to be operated by depression of a brake pedal for producing master cylinder pressure and a wheel brake assembly movably mounted to a road wheel to be operated by the master cylinder pressure applied thereto for applying a braking force to the road wheel in accordance with the depression force of the brake pedal. The braking device includes a hydraulic servo unit mounted on an axle housing of the road wheel and operatively connected to the wheel brake assembly for generating a servo-pressure in a predetermined relationship with the braking force in response to movement of the wheel brake assembly and a hydraulic control device arranged to apply the servo-pressure to the wheel brake assembly when the servo-pressure does not increase in a predetermined relationship with a increase of the master cylinder pressure.