Robert Boschgmbh

Marc Rodriguez

Laurent Lhuillier

Olivier Bernadat

Daniel Grech

Marc Noblet

Julien Gateau

Carole Charpentier

Serge Aquino

Antony Auguste

François Gaget

A primary piston of a tandem master cylinder includes: a body provided with a skirt, having in the rear thereof a cavity for the plunger and the push rod connected to the brake pedal and in the front a cavity defining the primary chamber. The piston is made of a plastic material and at least one magnet is built into the body of the piston.

Primary piston of a tandem master cylinder

A primary piston composed of a skirt and an intermediate back wall having a rear face receiving the servobrake thrust rod and a forward face for the telescoping rod and the spring pushing the secondary piston. The front of the skirt has longitudinal grooves open in front and closed in the rear. The thickness of the skirt beneath the grooves and the part of the skirt between two successive grooves in the peripheral direction form a front face enabling the principal piston to push the secondary piston. The principal piston is made of a single piece of plastic material.

Primary piston for a tandem master cylinder and tandem master cylinder equipped with such a primary piston

A master-cylinder seal housed in a groove around a piston has a core connected to three annular and concentric lips. The core rests against a side of the groove and has: a surface provided with an interior edge followed by a peripheral platter cut by at least one channel, and an exterior crown provided with a connection zone formed by an interruption in the crown and deformable due to pressure within the seal to recreate the crown's continuity and impermeability while facilitating purging the brake system when there is no pressure in the channel and the connection zone.

Brake system master-cylinder seal

A primary piston of molded plastic material equipped with a metallic insert and having grooves, mounted in a master cylinder comprising at least a primary piston and a secondary piston mounted in the bore hole of the master cylinder. These pistons can create pressure, respectively, in a primary pressure chamber and in a secondary pressure chamber due to the action of a push rod on the primary piston.

Plastic primary piston with insert for a tandem penetration-type master cylinder and a master cylinder equipped with such a piston

A brake fluid reservoir is connected to a master cylinder by a neck which is arranged in an upper chamber of the master cylinder. Holes extend through a surface of a piston, opening to a pressure chamber. The piston extends through a bore hole of the master cylinder. A drill hole extends through an interior wall of the master cylinder, opening into the bore hole, thereby providing communication between the fluid reservoir and the pressure chamber. A floating orifice plate is arranged within the upper chamber, between the neck of the brake fluid reservoir chamber and the drill hole, such that the orifice plate forms a baffle that limits a flow rate of liquid from the brake fluid reservoir chamber to the pressure chamber; and includes supports pressing against a surface of the interior wall of the master cylinder and arranged around the first side of the drill hole.

Master cylinder with flow limitation system

A master cylinder includes at least one primary piston and one secondary piston installed in the bore hole of the master cylinder, which pistons are used to create pressure. The primary piston has a body of molded plastic material and is equipped with a functional metallic insert which has the shape of a spherical cap capable of accommodating a push rod.

Plastic primary piston with stamped sheet-metal functional insert for penetration-type tandem master cylinder and master cylinder equipped with such a piston

A master cylinder having a primary piston and a secondary piston is described. The secondary piston is realized of plastic material; it is composed of a skirt and an end wall. The forward edge of the skirt is equipped with longitudinal slots intended to cooperate with the resupply seal to resupply the secondary pressure chamber and ensure operation in rest position whenever the brake circuit is in ESP mode. Supply occurs from the supply chamber, which is connected to the brake fluid reservoir.

Tandem master cylinder secondary piston and master cylinder equipped with such a secondary piston

A primary piston is described of molded plastic and equipped with a functional metallic insert and at least one groove. The primary piston is installed in a master cylinder comprising at least the primary piston and a secondary piston, these being mounted in the bore hole of a master cylinder. These pistons can create pressure in a primary pressure chamber and a secondary pressure chamber, respectively, due to the action of a push rod on the primary piston.

Primary plastic piston with functional insert for a penetration-type master cylinder and a master cylinder equipped with such a piston

Master-cylinder seal housed in a groove around a piston has a core connected to three annular and concentric lips. The core rests against a side of the groove and has: a surface provided with an interior edge followed by a peripheral platter cut by at least one channel, and an exterior crown provided with a connection zone formed by an interruption in the crown and deformable due to pressure within the seal to recreate the crown's continuity and impermeability while facilitating purging the brake system when there is no pressure in the channel and the connection zone.

A cup for a master cylinder coming into contact with its primary piston or its secondary piston and subjected to the pressure of the brake fluid of the primary chamber and of the secondary chamber. The cup has two large grooves bordered: by a rib between the heel and the first groove, by a rib between the first groove and the second groove, by a rib between the second groove and the small grooves, these ribs being in protrusion relative to the cylindrical surface of the heel in the mounted position of the cup in order to separate the heel from the surface of the piston and form, between the heel and the surface of the piston, a gap with a film of brake fluid. Master cylinder notably a tandem master cylinder fitted with such cups.

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Beverly Hills, MI, United States of America

Marc Rodriguez