Actuating system for a vehicle brake and method of operating the actuating system

Abstract

The invention relates to an actuating system for a vehicle brake, with an actuating arrangement, in particular a brake pedal, at least one (first) piston-cylinder unit, which is connected via a hydraulic line to the vehicle brake (braking circuit) in order to supply the braking circuit with pressure medium and apply pressure to the vehicle brake, and with a drive for the piston-cylinder unit. According to the invention, pressure medium can be fed to the braking circuit in controlled manner in both piston movement directions, in particular the advance stroke and the return stroke, by means of at least one, in particular stepped, piston ( 10 ) of the piston-cylinder unit ( 10, 10 a, 10 b ).

1 - 50 . (canceled) 
     
     
         51 . An actuating device for a vehicle brake, comprising:
 an actuating arrangement,   at least a first pressure source, comprising a first piston-cylinder unit having a master cylinder, configured to be actuated by means of the actuating arrangement, and   a second pressure source, comprising a second piston-cylinder unit with an electromechanical drive,   wherein the first and second pressure sources are connected with at least one braking circuit via a hydraulic line, in order to supply the at least one braking circuit with pressure medium and to apply pressure to the vehicle brake, and wherein the actuating device further comprises a valve arrangement configured to regulate the brake pressure,   wherein, by means of the piston of the second piston-cylinder unit of the second pressure source, wherein the piston of the second piston-cylinder unit is a stepped piston, at least one braking circuit is supplied with pressure medium in a controlled manner during both forward and return piston strokes.   
     
     
         52 . The actuating device according to  claim 51 , wherein no valves are arranged in a line section between the first pressure source and the valve arrangement. 
     
     
         53 . The actuating device according to  claim 51 , wherein the first piston-cylinder unit comprises one or two pistons. 
     
     
         54 . The actuating device according to  claim 51 , wherein the second piston-cylinder unit forms two or three pressure chambers. 
     
     
         55 . The actuating device according to  claim 51 , further comprising a third piston-cylinder unit, wherein a working chamber of the third piston-cylinder unit is connected with at least one working chamber of the second piston-cylinder unit, the first piston-cylinder unit, or both the first and second piston-cylinder units by means of a hydraulic line, in which a valve arrangement is arranged. 
     
     
         56 . The actuating device according  claim 51 , wherein a hydraulic connecting line is disposed between a pressure chamber of the second pressure source and a pressure chamber delimited by the rear of the piston of the first piston-cylinder unit, wherein at least one solenoid valve is disposed in the hydraulic connecting line and is configured to control a piston of the first piston-cylinder unit. 
     
     
         57 . The actuating device according to  claim 51 , further comprising a third piston-cylinder unit having a pressure chamber connected via a hydraulic line with a travel simulator and via asolenoid valve with at least one braking circuit. 
     
     
         58 . The actuating device according to  claim 55 , wherein the third piston-cylinder unit comprises a force-travel simulator. 
     
     
         59 . The actuating device according to  claim 55 , wherein a pressure chamber of the third piston-cylinder is connected via a hydraulic connecting line and at least one solenoid valve with at least one braking circuit. 
     
     
         60 . The actuating device according to  claim 51 , further comprising a hydraulic connecting line with a solenoid valve, wherein the hydraulic connecting line with the solenoid valve is arranged between a pressure chamber of a piston of the second piston-cylinder unit and at least one braking circuit for prefilling from the pressure chamber of the piston of the second piston-cylinder unit. 
     
     
         61 . The actuating device according to  claim 51 , wherein the electromechanical drive comprises an electric motor, wherein the electric motor is arranged parallel to and is configured to drive the second piston-cylinder unit. 
     
     
         62 . The actuating device according to  claim 51 , wherein, if the vehicle is idle or at a standstill, hydraulic systems and lines or pressure chambers are pressure-balanced in an equalisation reservoir by means of open valves to a return line. 
     
     
         63 . The actuating device according to  claim 51 , wherein, by means of the first pressure source, through the design of seals and/orvalve switching, a depression is developed for setting a lining clearance. 
     
     
         64 . A method of operating the actuating device according to  claim 51 , the method comprising:
 using a delivery volume of the second pressure source for pressure-related correlation with a pressure-volume curve of one or more individual wheel brakes for diagnosis of leaks in the at least one braking circuit and, if necessary, shutting down one or more braking circuits diagnosed as having leaks, or for diagnosis of a presence of air in the at least one braking circuit.   
     
     
         65 . A method of operating the actuating device according to  claim 51 , that the method comprising:
 using a defined delivery volume of the second pressure source, oriented towards a pressure-volume curve of a respective wheel, for pressure build-up or pressure reduction via a respective inlet valve or exhaust valve for controlling the second pressure source.   
     
     
         66 . The method according to  claim 64 , further comprising developing a depression for setting a lining clearance, using the second piston-cylinder unit. 
     
     
         67 . An actuating system for a vehicle brake, comprising:
 an actuating arrangement,   at least a first pressure source, comprising a first piston-cylinder unit having a master cylinder, configured to be actuated by means of the actuating arrangement, a second pressure source, comprising a second piston-cylinder unit, with an electromechanical drive,   wherein the first and second pressure sources are connected via a respective hydraulic line with at least one braking circuit, to supply the braking circuit with pressure medium and to apply pressure to the vehicle brake, and   a valve arrangement configured to regulate brake pressure,   wherein, by means of the second piston-cylinder unit, during forward and return piston strokes, at least one braking circuit is arranged to be supplied with pressure medium in a controlled manner.   
     
     
         68 . The actuating device according to  claim 51 , wherein, in at least one hydraulic line from the first pressure sourceto the valve arrangement, no valves are arranged. 
     
     
         69 . An actuating system for a vehicle brake, comprising:
 an actuating arrangement,   at least a first pressure source, comprising a first piston-cylinder unit having a master cylinder, configured to be actuated by means of the actuating arrangement,   a second pressure source, comprising a second piston-cylinder unit, with an electromechanical drive,   wherein the first and second pressure sources are connected via a respective hydraulic lines with at least one braking circuit, to supply the braking circuit with pressure medium and to apply pressure to the vehicle brake, and   a valve arrangement configured to regulate brake pressure,   wherein, between a pressure chamber of a double stroke piston of the second pressure source and a pressure chamber delimited by a rear of the piston of the first piston-cylinder unit of the first pressure source, a hydraulic connecting line exists, in which at least one solenoid valve configured to control various operating modes is arranged.   
     
     
         70 . The actuating device according to  claim 51 , wherein solenoid valves are arranged in first and second hydraulic lines connecting the first pressure source and second pressure source with the valve arrangement, and wherein a pressure sensor is arranged in only one of these first and second hydraulic lines or in a further hydraulic line leading from the second piston-cylinder unit to the valve arrangement. 
     
     
         71 . The actuating device according to  claim 51 , further comprising non-return valves or solenoid valves arranged in hydraulic lines connecting together pressure chambers of the second piston-cylinder unit, the non-return valves or solenoid valves being arranged for controlling pressure medium inflow and outflow. 
     
     
         72 . The actuating device according to  claim 71 , further comprising a pressure relief valve disposed in a hydraulic line connecting the hydraulic lines in which the non-return valves or solenoid valves are arranged. 
     
     
         73 . The actuating device according to  claim 51 , further comprising:
 a third piston-cylinder unit, comprising a pressure chamber;   a hydraulic line connecting the pressure chamber of the third piston-cylinder unit with at least one braking circuit; and   a solenoid valve arranged for feeding pressure medium into the at least one braking circuit and disposed in the hydraulic line connecting the pressure chamber of the third piston-cylinder unit and the at least one braking circuit.   
     
     
         74 . The actuating device according  claim 51 , further comprising a spring arranged on one piston of the first piston-cylinder unit. 
     
     
         75 . The actuating device according to  claim 51 , further comprising a third piston-cylinder unit, wherein a counterforce is applied using a piston of the second piston-cylinder unit, in order to reduce pressure in the third piston-cylinder unit. 
     
     
         76 . The actuating device according to  claim 51 , wherein the first piston-cylinder unit comprises a plunger rod piston and a floating piston, wherein the plunger rod piston has only one seal, and wherein the plunger rod piston and the floating piston are coupled together by means of a spring housing of the plunger rod piston. 
     
     
         77 . The actuating device according to  claim 76 , further comprising a diagnostic circuit for testing one or more seals associated with one or more pistons. 
     
     
         78 . The actuating device according to  claim 51 , further comprising a third pressure source, comprising a third piston-cylinder unit, disposed upstream of the first pressure source. 
     
     
         79 . The actuating device according to  claim 51 , wherein the second pressure source comprises a motorised pump with an associated solenoid valve or non-return valve. 
     
     
         80 . The actuating device according to  claim 51 , further comprising:
 a third piston-cylinder unit; and   a travel simulator arrangement configured to interact with the third piston-cylinder unit.   
     
     
         81 . A method of operating the actuating device according to  claim 51 , the method comprising:
 supplying pressure medium to a rear of a piston of the first piston-cylinder unit of the actuating device according to  claim 51  by means of the second piston-cylinder unit of the actuating device according to  claim 51 .   
     
     
         82 . The method according to  claim 81 , further comprising developing pressure in braking circuits without the use of isolation valves. 
     
     
         83 . The method according to  claim 81 , further comprising controlling various operating modes using at least one solenoid valve. 
     
     
         84 . An actuating system for a vehicle brake, comprising:
 an actuating arrangement,   at least a first pressure source, comprising a first piston-cylinder unit having a master cylinder, configured to be actuated by means of the actuating arrangement,   a second pressure source, comprising a second piston-cylinder unit, with an electromechanical drive,   wherein the first and second pressure sources are connected via a respective hydraulic lines with at least one braking circuit, to supply the braking circuit with pressure medium and to apply pressure to the vehicle brake, and   a valve arrangement configured to regulate brake pressure, wherein the first piston-cylinder unit comprises just a single pressure-developing piston.   
     
     
         85 . The actuating device according to  claim 51 , wherein at least one pressure chamber of the second piston-cylinder unit is hydraulically connected with a pressure or working chamber formed on a rear of a piston of the first piston-cylinder unit, via a further valve arrangement. 
     
     
         86 . The actuating system according  claim 84 , further comprising:
 a third piston-cylinder unit; and   a travel simulator,   wherein the third pressure source or piston-cylinder unit is configured to supply the travel simulator with pressure medium and to supply at least one braking circuit with pressure medium in case of a pressure supply failure.   
     
     
         87 . The actuating system according to  claim 86 , wherein the third piston-cylinder unit comprises a cross bore, connected via a hydraulic line with a reservoir. 
     
     
         88 . The actuating system according to  claim 84 , wherein a working chamber of the single pressure-developing piston is connected via a cross bore, and via a solenoid valve or a throttle-non-return valve arrangement with a reservoir. 
     
     
         89 . The actuating system according to  claim 84 , wherein the actuating arrangement is arranged to act on a spring or spring combination of the single pressure-developing piston. 
     
     
         90 . The actuating system according to  claim 87 , further comprising a normally-open solenoid valve arranged in a hydraulic line from the third piston-cylinder unit to the travel simulator and to the at least one braking circuit. 
     
     
         91 . The actuating system according to  claim 87 , further comprising a normally-closed solenoid valve arranged in a hydraulic line from the third piston-cylinder unit to the travel simulator and to the reservoir. 
     
     
         92 . A method of operating the actuating system according to  claim 84 , the method comprising:
 supplying pressure medium to the rear of a piston of a first piston-cylinder unit of the actuating system of  claim 84 , by means of the second piston-cylinder unit of the actuating system according to  claim 84 .   
     
     
         93 . The method according to  claim 92 , further comprising developing pressure in braking circuits, by means of one or more of the piston-cylinder units, without the use of isolation valves. 
     
     
         94 . The method according to  claim 92 , further comprising controlling various operating modes using at least one solenoid valve. 
     
     
         95 . The method according to  claim 64 , further comprising supply pressure medium at the rear of a piston of the first piston-cylinder unit, using the second piston-cylinder unit. 
     
     
         96 . The method according to  claim 94 , further comprising developing pressure in braking circuits by means of at least one of the pressure sources, without the use of isolation valves. 
     
     
         97 . The method according to  claim 93 , further comprising controlling various operating modes using at least one solenoid valve. 
     
     
         98 . The method according to  claim 92 , further comprising using a pressure source or third piston-cylinder unit to supply pressure medium to a travel simulator and, in case of pressure supply failure, to a braking circuit. 
     
     
         99 . The method according to  claim 92  further comprising performing functional diagnostics, wherein a comparison is performed between a volume delivery of the second piston-cylinder unit and a pressure level achieved at the time of the diagnostics. 
     
     
         100 . A method of operating a braking device, the braking device having a first pressure source or piston-cylinder unit and a second pressure source including a second piston cylinder unit, in the form of a double stroke stepped piston, the method comprising:
 controlling at least one braking circuit using the stepped piston of the second piston-cylinder unit of the second pressure source during both forward and return strokes of the double stroke stepped piston.