Robert Boschgmbh

Olivier Bernadat

Laurent Lhuillier

Marc Rodriguez

Antony Auguste

Daniel Grech

Marc Noblet

Julien Gateau

François Gaffe

Carole Charpentier

Francois Gaffe

Yannick Nen

Serge Aquino

Philippe Bourlon

Jean-Pierre Michon

Bruno Beylerian

Omar Brahmi

François Gaget

Laurent Lhuiller

Bobam Gacic

Nicolas Scrivano

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 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.

Cup of a master cylinder, advantageously a tandem master cylinder and tandem master cylinder provided with such cups

Master cylinder of a hydraulic braking circuit, particularly for a motor vehicle, comprising a piston () sliding axially in a body () comprising an annular lip seal () produced by molding, and comprising an internal, dynamic sealing lip () surrounding the piston and connected by a curved surface () to a planar rear face () comprising radial passages which are defined by blocks formed as projections on the rear face of the seal, these blocks being separated from the curved surface ().

Braking circuit master cylinder lip seal

Master cylinder for a hydraulic braking circuit, particularly for a motor vehicle, comprising an annular seal () placed in a housing () of the body comprising an internal dynamic sealing lip () surrounding the piston, fitting into an annular groove () of the piston when this piston is in a rear rest position, an outer static sealing lip () pressing against a wall of the housing, and an additional static sealing lip () which presses against a wall of the housing of this seal and with the outer lip defines a small closed volume (V) of liquid.

Motor vehicle brake master cylinder seal

The invention relates to a master cylinder () with reduced free travel (). Current master cylinders have a free travel during the displacement of a piston () in a bore () of a master cylinder body (). Such a free travel may be reduced with the aid of a frustoconical portion () in the piston, an orifice () for communication of hydraulic fluid being situated on said inclined wall, a gap () between the inclined wall and an inner wall () of the bore allowing a passage for hydraulic fluid capable of filling a pressure chamber (). However, such inclined walls create a change in the slope of an outer wall () of the piston, this change being able to cause a separation of an inner lip () of a sealing cup (). To prevent this separation, the invention provides that the inclined wall forms a convex rounded surface ().

Master cylinder with reduced free travel

Brake master cylinder () for a motor vehicle, of the type which comprises a substantially axial body () inside a bore () of which at least one axial piston is slideably mounted, of the type in which the bore () comprises two seals, front () and rear, interposed between the piston and the bore (), the seals () comprising three radially concentric lips accommodated in grooves () in the bore (), characterized in that front faces of the grooves () are configured at least in part as a slope.

Master cylinder comprising a resupply-promoting seal

Brake master cylinder () for a motor vehicle, of the type which comprises a substantially axial body () inside a bore () of which at least one axial piston is slideably mounted, of the type in which the bore () comprises two seals, front () and rear, interposed between the piston and the bore (), the seals () comprising three radially concentric lips accommodated in grooves () in the bore (), characterized in that the seals () comprise central lips of reduced cross section.

Master cylinder comprising a seal and an associated groove promoting resupply

A pneumatic brake boostercomprising: a sealed structurecomprising a rigid casingforming a funnelfurnished with an opening and a movable walldividing the sealed structureinto a low-pressure chamberand a working chamber, a pneumatic pistoncomprising a bossfixedly attached to the movable walland mounted so as to slide in the funnel opening, a valve elementhoused in the bossand a sealpositioned between the bossand the funnel, an input rodand an output rodcoupled on either side of the pneumatic piston, and a return springto return the pneumatic pistonto a rest position, the return springbeing placed in the low-pressure chamberbetween an internal surfaceof the rigid casing and the pneumatic piston, and a force sensorplaced in the low-pressure chamberand subjected to the pressure variations of the return spring

Pneumatic brake booster comprising a force sensor

A master cylinder () having a bore () fitted with at least one piston () and at least one seal (). The seal () is partially stiffened by a reinforcement member (). In order to retain the piston () in the bore () a groove () is located on a circumference of the piston () against which the sealing member () bears with the piston () in a rest position to retain the piston () in bore ().

Growing community of inventors

Le Perreux, France

Olivier Bernadat