Master cylinder for an electro-hydraulic braking system comprising improved means of simulating the pedal feel and an electro-hydraulic braking system comprising such a master cylinder

摘要

The present invention relates mainly to a master cylinder for an electro-hydraulic braking system comprising improved means of simulating the pedal feel and to an electro-hydraulic braking system comprising such a master cylinder. ;The main subject of the present invention is a master cylinder for electro-hydraulic braking systems comprising a body of longitudinal axis pierced with a bore, a piston mounted to slide in sealed fashion in the bore and axially dividing the bore into a supply chamber sealedly connected to a brake fluid reservoir and a working chamber, the said piston being operated by an actuating rod connected to a brake pedal, and a cartridge simulating the reaction of a braking circuit at the pedal, the said working chamber in normal operation being in communication with the inside of the cartridge simulating the pedal feel and in degraded operation being in communication with at least one brake arranged at a wheel, the said cartridge comprising a piston able to be subjected, via a first face to the pressurized brake fluid supplied by the working chamber and subjected via a second face to a variable-stiffness elastic means, characterized in that the elastic means comprises at least one helical spring and a spacer means arranged between at least two turns of the said spring and allowing the said turns to press against the said spacer means when the pressure of the brake fluid in the working chamber exceeds a predetermined value.