Master cylinder with fluid level and pressure failure detector

摘要

A master cylinder having a housing with a first bore therein for retaining a pair of pistons which move in response to an input force and develop fluid pressure to effect a brake application. A second bore in the housing carries a differential area piston connected to the pressure chambers. A reed switch retained in the housing is aligned with a first magnet located on a float in a reservoir and a second magnet is attached to the differential area piston. A ferromagnetic shield located between the reed switch and second magnet has first and second openings located in a plane on either side of the reed switch. Should a failure occur in either pressure chamber, the differential area piston moves to allow magnetic field to pass through the openings in the shield and activate the reed switch to develop a warning signal and inform an operator of a failure mode condition in the master cylinder.