Abstract: A servo brake includes a thrust unit connecting a servo-piston to a primary piston in an actuation direction. The thrust unit includes a plunger with a front end in the form of a spherical cap and pressed in a cup of the primary piston and a rear end that includes a ball joint. A bearing has a base pressed on a reaction disc and a sleeve that receives the ball joint of the plunger.

Abstract: Master cylinder having a housing equipped with a borehole accommodating a primary piston. The housing, equipped with a stoplight control, has, on the one hand, a drill hole whose axis is parallel to that of the borehole accommodating the piston and accommodating a magnet whose movement is coupled to that of the piston and, on the other hand, a Hall sensor, which detects the movement of the magnet for controlling the stoplights. The stoplight control comprises a moving assembly translationally integral with the primary piston at its extremity and having a bracket movably affixed to the end of the piston exiting the housing and a rod whose axis is parallel to the axis of the drill hole, connected to a foot of the bracket and whose extremity, engaged in the drill hole, bears a magnet that cooperates with the Hall sensor.

Abstract: Master cylinder having a housing with a borehole accommodating a primary piston controlled by the actuator extending beyond the borehole. The housing has a stoplight control having a drill hole whose axis is parallel to that of the borehole accommodating the piston, wherein the drill hole accommodates a magnet whose movement is coupled to that of the (primary) piston, and a Hall sensor outside the housing that detects the movement of the magnet to control the stoplights. The stoplight control comprises a moving assembly translationally integral with the primary piston at its extremity and comprising a bracket removably affixed to the extremity of the primary piston exiting the housing and a rod whose axis is parallel to the axis of the drill hole, connected to the bracket and whose extremity, engaged in the drill hole, bears a magnet to cooperate with the Hall Sensor.

Abstract: A primary piston component for a master cylinder of a hydraulic brake system includes a primary piston housing and an additional piston component, which is configured to be at least partially movable into a cavity of the primary piston housing. An inner piston body extends through the cavity along a central line of the primary piston component. A braking force applied on a brake actuating element is transferable at least partially on the inner piston body, and further on the primary piston housing. The additional piston component is at least partially movable into the cavity between the inner piston body and the primary piston housing, and a brake booster force is transferable at least partially on the additional piston component, and via the inner piston body on the primary piston housing. A method of operating a hydraulic brake system is also described.

Abstract: A servo brake includes a thrust unit connecting a servo-piston to a primary piston in an actuation direction. The thrust unit includes a plunger with a front end in the form of a spherical cap and pressed in a cup of the primary piston and a rear end that includes a ball joint. A bearing has a base pressed on a reaction disc and a sleeve that receives the ball joint of the plunger.

Abstract: A primary piston component for a master cylinder of a hydraulic brake system includes a primary piston housing and an additional piston component, which is configured to be at least partially movable into a cavity of the primary piston housing. An inner piston body extends through the cavity along a central line of the primary piston component. A braking force applied on a brake actuating element is transferable at least partially on the inner piston body, and further on the primary piston housing. The additional piston component is at least partially movable into the cavity between the inner piston body and the primary piston housing, and a brake booster force is transferable at least partially on the additional piston component, and via the inner piston body on the primary piston housing. A method of operating a hydraulic brake system is also described.

Abstract: A cup seal (21) of the invention includes an intermediate lip portion (21d), positioned between an inner lip portion (21b) and an outer lip portion (21c), provided in a base portion (21a). The intermediate lip portion (21d) is configured in such a way that first intermediate lip portions (21d1), communication passages (21d3), second intermediate lip portions (21d2), whose axial direction length is less than that of the first intermediate lip portions (21d1), and the communication passages (21d3), which have no lip portion, are cyclically disposed, in this order, in the peripheral direction. An easy elastic deformation portion of the base portion (21a) which elastically deforms easily is formed by the second intermediate lip portions (21d2) and communication passages (21d3) and, by the easy elastic deformation portion elastically deforming easily when supplying liquid, a flow passage with a larger passage area is formed.

Abstract: A projection (21b4) provided at a tip portion of an inner lip portion (21b) of a first cup seal (21) comes in contact with a second side wall (20c) of a recessed portion (20) and a large axial force is exerted in the axial direction on a first tapered inner peripheral surface (21b1) of the first cup seal (21) from a rear side tapered surface (4b2) of a primary piston (4). This makes it possible to reliably hold the first cup seal (21) in the axial direction by utilizing the axial force. Therefore, the first cup seal (21) can be suppressed from moving in the axial direction. In particular, the projection (21b4) of the first cup seal (21) comes in contact with a tapered surface (20c?) of the second side wall (20c) to obtain a further increased axial force, and the first cup seal (21) can be held more reliably.

Abstract: A cup seal (21) of the invention includes an intermediate lip portion (21d), positioned between an inner lip portion (21b) and an outer lip portion (21c), provided in a base portion (21a). The intermediate lip portion (21d) is configured in such a way that first intermediate lip portions (21d1), communication passages (21d3), second intermediate lip portions (21d2), whose axial direction length is less than that of the first intermediate lip portions (21d1), and the communication passages (21d3), which have no lip portion, are cyclically disposed, in this order, in the peripheral direction. An easy elastic deformation portion of the base portion (21a) which elastically deforms easily is formed by the second intermediate lip portions (21d2) and communication passages (21d3) and, by the easy elastic deformation portion elastically deforming easily when supplying liquid, a flow passage with a larger passage area is formed.

Abstract: A projection (21b4) provided at a tip portion of an inner lip portion (21b) of a first cup seal (21) comes in contact with a second side wall (20c) of a recessed portion (20) and a large axial force is exerted in the axial direction on a first tapered inner peripheral surface (21b1) of the first cup seal (21) from a rear side tapered surface (4b2) of a primary piston (4). This makes it possible to reliably hold the first cup seal (21) in the axial direction by utilizing the axial force. Therefore, the first cup seal (21) can be suppressed from moving in the axial direction. In particular, the projection (21b4) of the first cup seal (21) comes in contact with a tapered surface (20c?) of the second side wall (20c) to obtain a further increased axial force, and the first cup seal (21) can be held more reliably.

Abstract: In a cup seal, the hydraulic pressure in a first hydraulic chamber (6) causes a first seal portion (21e) of an outer lip portion (21c) to closely contact to a bottom wall (20a) of a recessed portion (20) and causes a second seal portion (21f) of a base portion (21a) to closely contact to a rear surface (20b) of the recessed portion (20). A double seal due to the first and second seal portions (21e) and (21f) reliably prevents the leakage of a brake fluid from the first hydraulic chamber (6). If the pressure becomes negative in the first hydraulic chamber (6), the tip portion of the outer lip portion (21c) deflects inward and the outer peripheral end of the base portion (21a) deflects forward. Therefore, the brake fluid in the reservoir flows into the first hydraulic chamber (6) through the gaps among the second and first seal portions (21f), (21e) and the wall surface of the recessed portion (20) to maintain fluid-feeding performance.