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AssigneeRobert Bosch GmbH
InventorAnderson Chris
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A master cylinder for electro-hydraulic braking systems having a body of longitudinal axis pierced with a bore to receive a piston mounted to slide therein in a sealed fashion while axially dividing the bore into a supply chamber sealedly connected to a brake fluid reservoir and a working chamber. The piston is operated by an actuating rod connected to a brake pedal and connected to a cartridge to simulate a reaction of a braking circuit to the pedal. The working chamber in normal operation is in communication with the inside of the cartridge and in degraded operation in communication with at least one brake located at a wheel. The cartridge includes a piston that is subjected via of a first face to the pressurized brake fluid supplied by the working chamber and is subjected via of a second face to a variable-stiffness elastic of a elastic member. The elastic member comprises at least one helical spring and a spacer that is arranged between at least two turns of the spring. The spacer allows turns to press against the spacer when the pressure of the brake fluid in the working chamber exceeds a predetermined value.
A master cylinder for electro-hydraulic braking systems comprising a body (2) of longitudinal axis (X) pierced with a bore (4), a piston (10) mounted to slide in sealed fashion in the bore and axially dividing the bore into a supply chamber (22) sealedly connected to a brake fluid reservoir (R) and a working chamber, said piston being operated by an actuating rod connected to a brake pedal, and a cartridge (28) simulating the reaction of a braking circuit at the pedal, said working chamber (24) in normal operation being in communication with the inside of the cartridge (28) simulating the pedal feel and in degraded operation being in communication with at least one brake arranged at a wheel, said cartridge (28) comprising a piston (42) that is subjected, via a first face (44) to pressurized brake fluid supplied by the working chamber (24) and subjected via a second face (46) to a variable-stiffness elastic means (48), characterized in that the elastic means (48) comprises at least one helical spring (78) and a spacer means (80) arranged between at least two turns (Sn) of said spring (79) and allowing said turns to press against said spacer means (80) when the pressure of the brake fluid in the working chamber (24) exceeds a predetermined value.
Dependencies are inferred from the claim text.