Brake system

Abstract

A brake system may include an actuation device, in particular a brake pedal; a first piston-cylinder unit with two pistons, in particular an auxiliary piston and a second piston, in order to supply brake circuits with a pressure medium via a valve device, wherein one of the pistons, in particular the auxiliary piston, can be actuated by means of the actuation device; a second piston-cylinder unit comprising an electric motor-powered drive, a transmission, and at least one piston in order to supply pressure medium to at least one of the brake circuits via a valve device; and a motor pump unit with a valve device in order to supply pressure medium to the brake circuits. The brake system may further include a hydraulic travel simulator which is connected to a pressure or working chamber of the first piston-cylinder unit.

1 .- 26 . (canceled) 
     
     
         27 . A brake system, comprising:
 an actuating device,   a first piston-cylinder unit having a first piston and a second piston, arranged to supply at least one first brake circuit and at least one second brake circuit with pressure medium via a valve device, wherein the first piston is enabled to be actuated by means of the actuating device, wherein the first piston-cylinder unit comprises a first pressure chamber or a first working chamber in which the first piston is arranged and to which at least the second brake circuit is connected, wherein the first piston-cylinder unit comprises a second pressure chamber or a second working chamber, to which at least the first brake circuit is connected,   a second piston-cylinder unit with an electromotive drive, a transmission and at least one piston for supplying pressure medium to at least one of the brake circuits via a valve device,   a motor-pump unit, with a valve device, arranged to supply pressure medium to the first and second brake circuits,   a hydraulic travel simulator connected to one of the first or second pressure chambers or working chambers of the first piston-cylinder unit,   
       wherein a pressure or working chamber of the second piston-cylinder unit is connected to the first brake circuit via a hydraulic line and is supplied with pressure via the first piston, and wherein the second piston-cylinder unit is aligned parallel to the axis of the first piston-cylinder unit. 
     
     
         28 . The brake system according to  claim 27 , wherein the brake system is designed for a subsequent conveying of volumes from a storage container during the piston return stroke of the second piston-cylinder unit via a suction valve, wherein the suction valve and a breather hole of the second piston-cylinder unit are connected to the storage container via a return line. 
     
     
         29 . The brake system according to  claim 27 , wherein the first piston-cylinder unit has a partition wall with a seal for a penetrating plunger, for forming a third pressure chamber or a third working chamber, in which a piston is arranged, which is connected via a valve device to a brake circuit. 
     
     
         30 . The brake system according to  claim 29 , wherein, in the event of failure of the first brake circuit, the plunger transmits force of the actuating device to the second piston and thus generates pressure in the second brake circuit. 
     
     
         31 . The brake system according to  claim 30 , wherein the plunger has a smaller cross-sectional area than the first and second pistons of the first piston-cylinder unit, by at least a factor of 5, and contributes insignificantly to pressure build-up and serves for pressure sensing in at least one of the brake circuits, and the plunger further transmits a force to the actuating device and thus generates a haptic feedback to the actuating device. 
     
     
         32 . The brake system according to  claim 27 , further comprising a control device arranged to enable a motor of the electromotive drive of the second piston-cylinder unit and a motor of the motor-pump unit to be used together or independently of one another. 
     
     
         33 . The brake system according to  claim 27 , wherein, in the event of failure of the motor-pump unit, an ABS function is carried out by a piston control of the second piston-cylinder unit together with pressure regulating valves of the motor-pump unit. 
     
     
         34 . The brake system according to  claim 27 , wherein the second piston-cylinder unit is only effective in a specific pressure range, and wherein the motor-pump unit is used for pressure generation for a further, higher pressure range. 
     
     
         35 . The brake system according to  claim 27 , wherein control of the second piston-cylinder unit is carried out via travel of the actuating device and control of pressure is carried out by means of a corresponding brake booster characteristic, wherein instead of the pressure, the motor current is used for regulating the second piston-cylinder unit. 
     
     
         36 . The brake system according to  claim 27 , wherein a pressure-volume characteristic is used for controlling the second piston-cylinder unit and for diagnosis, wherein the brake system is designed to detect a failure of one of the brake circuits by comparing pressure-volume characteristics, wherein the pressure-volume characteristic is stored in a characteristic map at intervals as part of a diagnostic cycle. 
     
     
         37 . The brake system according to  claim 27 , wherein the first piston and the second piston of the first piston-cylinder unit have different diameters. 
     
     
         38 . The brake system according to  claim 27 , further comprising a two-box, wherein a first module of the two-box is connected to a 12V battery or 12V voltage network and a second module of the two-box is connected to a DC/DC converter or other on-board network with a higher voltage than 12V. 
     
     
         39 . The brake system according to  claim 38 , wherein both of the first and second modules of the two-box are each connected redundantly both to the 12V battery or voltage network and to the DC/DC converter or other on-board network with a higher voltage than 12V. 
     
     
         40 . The brake system according to  claim 27 , wherein four-wheel blending takes place for a recuperation control, wherein a pressure control takes place via a piston with open valves of the valve device of the motor-pump unit, and/or wherein the transmission comprises a trapezoidal spindle with self-locking, having a self-locking action in the event of failure of the electromotive drive. 
     
     
         41 . The brake system according to  claim 27 , wherein a plug connection for the brake system is arranged below a storage container and is directed inwards towards a center of the brake system in order to enable a lateral removal of an associated plug. 
     
     
         42 . The brake system according to  claim 27 , wherein the second piston of the first piston-cylinder unit has, in addition to a passage in form of a breather hole which is provided with two seals, a further passage which is provided with a further seal, and which is connected via a throttle to a line leading to a storage container.