DE102014117726A1 - Actuation system for a motor vehicle brake - Google Patents

Abstract

The invention relates to an actuating system, in particular for a vehicle brake, having an actuating device, such as a brake pedal, at least one first pressure source (2) which can be actuated in particular by means of the actuating device and a second pressure source (4) with an electromechanical drive (14, 16). , wherein the pressure sources (2, 4) in each case via at least one hydraulic line or a hydraulic circuit (BK1, BK2) with at least one consumer or actuator, in particular a wheel brake are connected to supply the consumer or actuator pressure medium and pressurize , And with a first valve means (VBL) for pressure control, characterized in that by means of the second pressure source (4), in two movement or actuation directions, which are in particular linear, rotational directions or the advance and return stroke of a piston, at least one hydraulic line or a hydraulic circuit (BK1, BK2), in particular brake circuit, g Controlled pressure medium can be supplied.

Description

Name of the invention

The invention relates to an actuating system, in particular for a motor vehicle brake, according to the preamble of claim 1, and a method for operating such an actuating system.

State of the art

In the PCT / EP2014 / 069650 the applicant is already described an actuating system of the type mentioned. Although this system already represents a significant improvement over the prior art, further optimization in terms of design and flexibility of functions is desirable.

Object of the invention

The invention is therefore an object of the invention to provide an inexpensive operating system with short length and flexibility for many functions.

Solution of the task

The object is achieved according to the invention with the features of claim 1 and the patent claim 23rd

With the solution according to the invention an actuating system and a method for their operation is provided, which not only solve the task of the invention in a surprisingly advantageous manner, but they also bring many other advantages and opportunities with it.

Advantageous embodiments or refinements as well as further advantages emerge from the further claims, to which reference is made here.

According to the invention pressure build-up and pressure reduction take place in particular by an interaction of the first pressure source and the second pressure source and various valve devices. For this purpose, the pressure sources each have at least two working chambers, wherein each one working chamber of the pressure sources via hydraulic connecting lines, in which valve means are arranged, are interconnected. Through these connections, the work spaces in response to movements of the movable elements of the pressure sources (in particular the piston SK, DK, DHK) and of the valve means (in particular one or more of the valves AV, RV1 or MV / RV1, VF, MV / RV2 , AVDHK, AVz) interact with each other in a variety of controlled ways.

According to the invention, a pressure build-up by means of the second pressure source can take place directly via valve devices in at least one brake circuit and / or indirectly or indirectly via the first pressure source. In this case, the pressure build-up in the first pressure source causes hydraulic volume to be conveyed into the second pressure source, as a result of which a movable element of the first pressure source moves or displaces, thereby conveying volume into at least one brake circuit.

If the first pressure source has a piston-cylinder unit, this can advantageously have one or two pistons. If the second pressure source conveys hydraulic volume to the first pressure source, in particular as described above, this is expediently carried out in a (second) working chamber on the rear side of the piston SK or, in the case of two pistons, a (third) working chamber on the rear side of the piston DK ie of the means of the actuator directly operable piston.

The pressure reduction can be carried out in the invention advantageously in different ways or different ways, especially during the return stroke of a motor-driven Doppelhubkolbens (DHK), with different valve devices or valve circuits allow very flexible adaptation to different conditions. An alternative to Doppelhubkolben (DHK) as a piston feed pump, a displacement or feed pump, in particular a 2-wheel, vane or radial piston pump can be used, in particular together with a solenoid valve for feeding the volume in the brake circuits (BK).

To reduce the noise, the speed can be reduced via a transmission gear to the motor with appropriate dimensioning of the pump. Possibly. The motor pump unit can also be silenced with the remaining units, valve block and the first piston-cylinder unit (master cylinder).

According to an advantageous embodiment, it is provided that two working spaces of the second pressure source, in particular the piston-cylinder unit, are connected to one another or connectable via a hydraulic line in which a fourth valve device (VF) is arranged. In ABS operation and promotion of the volume for the pressure build-up in the wheel brakes are preferably supplied via the open valve (VF) both wheel circuits.

A pressure reduction in a brake system takes place in particular in the ABS case, at the brake end and / or if there is too much volume in one or both brake circuits. For the pressure reduction, there are various advantageous variants according to the invention.

• a) Volumenförderung aus einem ersten Bremskreis (BK1) indirekt über Ventileinrichtungen (insbesondere VF und RV2 bzw. MV/RV2) in einen zweiten Bremskreis (BK2) und aus dem zweiten Bremskreis (BK2) direkt über eine Ventileinrichtung (insbesondere AV) in einen Vorratsbehälter;
• b) Volumenförderung aus einem ersten Bremskreis (BK1) über die zweite Druckquelle, insbesondere Rückhub des Doppelhubkolbens (DHK) und eine Ventileinrichtung (insbesondere RV1 bzw. MV/RV1) und aus einem zweiten Bremskreis (BK2) über Ventileinrichtungen (insbesondere RV2 bzw. MV/RV2) aus einem zweiten Bremskreis (BK2);
• c) Volumenförderung aus einem ersten Bremskreis (BK1) über die zweite Druckquelle, insbesondere Rückhub des Doppelhubkolbens (DHK), über eine Ventileinrichtung (insbesondere RV1 bzw. MV/RV1) in einen ersten Arbeitsraum (insbesondere Arbeitsraum 4a) des Doppelhubkolbens (DHK) und Volumen aus einem zweiten Arbeitsraum (insbesondere Arbeitsraum 4b) des Doppelhubkolbens (DHK) über eine Ventileinrichtung (insbesondere AV DHK) in einen Vorratsbehälter und Volumenförderung aus einem zweiten Bremskreis (BK2) über die erste Druckquelle, insbesondere durch Bewegung bzw. Verschiebung zumindest eines Kolbens (SK, DK) einer als Kolben-Zylinder-Einheit ausgebildeten ersten Druckquelle.
• d) Volumenförderung aus einem ersten Bremskreis (BK1) über eine Ventileinrichtung (insbesondere Ventile VF und AVDHK) und aus einem zweiten Bremskreis (BK2) über eine weitere Ventileinrichtung (insbesondere Ventile R2 bzw. MV/RV2 und AVDHK).

In principle, the pressure reduction can advantageously be carried out in particular as follows:

• a) volume delivery from a first brake circuit (BK1) indirectly via valve devices (in particular VF and RV2 or MV / RV2) in a second brake circuit (BK2) and from the second brake circuit (BK2) directly via a valve device (in particular AV) in a reservoir ;
• b) volume delivery from a first brake circuit (BK1) via the second pressure source, in particular return stroke of Doppelhubkolbens (DHK) and a valve device (in particular RV1 or MV / RV1) and from a second brake circuit (BK2) via valve means (in particular RV2 or MV / RV2) from a second brake circuit (BK2);
• c) volume delivery from a first brake circuit (BK1) via the second pressure source, in particular return stroke of the Doppelhubkolbens (DHK), via a valve device (in particular RV1 or MV / RV1) in a first working space (in particular working space 4a) of the Doppelhubkolbens (DHK) and Volume from a second working space (in particular working space 4b) of the Doppelhubkolbens (DHK) via a valve device (in particular AV DHK) in a reservoir and volume delivery from a second brake circuit (BK2) via the first pressure source, in particular by movement or displacement of at least one piston ( SK, DK) of a piston-cylinder unit formed as the first pressure source.
• d) volume delivery from a first brake circuit (BK1) via a valve device (in particular valves VF and AVDHK) and from a second brake circuit (BK2) via a further valve device (in particular valves R2 or MV / RV2 and AVDHK).

According to a further advantageous embodiment, an additional (fifth) valve device (AVDHK) is provided, which is arranged in a hydraulic line which connects the second working space of the second pressure source, in particular a piston-cylinder unit, with a reservoir. With the additional valve device (AVDHK), which connects the rear pressure chamber of the double-stroke piston (DHK) with the reservoir (VB), a large effective area of the double-stroke piston (DHK) can be switched on, so that even from a high pressure range due to the large volume the full pressure on the return stroke can be reduced. This has the advantage that the brake circuits (BK) do not have to be opened via the exhaust valves (AV) and an additional diagnosis of the tightness of these valves is not necessary. This valve circuit is also advantageous in multiplex (MUX) operation.

An alternative possibility of pressure reduction is that during the return stroke of the movable element of the second pressure source, in particular the piston, pressure medium from the second working space is discharged into the reservoir, in particular the pressure reduction from a brake circuit (BK1) via the second valve device (MV / RV1 takes place in the work space.

A further advantageous embodiment provides for the pressure reduction from the brake circuits (BK1, BK2) at least one further (sixth) valve device (AVz1, AVz2) associated with a brake circuit, which connects in a hydraulic connecting line which connects the brake circuit (BK1, BK2) to the reservoir , is arranged.

The pressure reduction from a brake circuit (BK1) can also take place via a hydraulic connecting line to the reservoir, in which a third valve device (RV2) and a fourth valve device (VF) are arranged.

Due to the large volume delivery can be more volume in the brake circuit (BK) than the volume to reduce pressure in the working space of the Doppelhubkolbens (DHK). During pressure reduction, the excess volume can initially be transferred to the storage container (VB) via one of the exhaust valves (AV) known in brake systems. Then then the pressure reduction over the o. G. Valve circuits, i. the additional valve devices (AVDHK with open valve MV / RV2 and AVz1, AVz2) and the double-stroke piston (DHK) take place. In the case of multiplex (MUX) operation, pressure also has to be reduced via the valves (AV) in order, for. B. in negative μ-jump back into the working range of the double-stroke piston DHK for pressure build-up and pressure reduction to come.

The pressure reduction at the end of a braking process can take place both via one or more exhaust valves, in particular with a connection of both brake circuits (BK) via valve devices (VF and MV / RV2) or only in a brake circuit (BK1) via a valve device (VF). Preferably, a valve device with only one additional outlet valve (AVDHK) is provided. By opening a valve device (in particular RV1 or MV / RV1, pressure can be released from a brake circuit (in particular BK1) and also via the first pressure source (in particular the piston SK) in a second brake circuit (BK2) arranged valve device (in particular valve VF) is closed in this case.

Alternatively, the pressure reduction over the return stroke of the second pressure source, in particular the Doppelhubkolbens (DHK) via a valve device (MV / RV1) on Doppelhubkolben (DHK) take place with only the small effective area (A1-A2) of the Doppelhubkolbens is effective, which is a particularly quiet and accurate pressure control results or via the additional valve device AVDHK, as well as the valve devices (MV / RV1, MV / RV2, AVDHK), wherein the full effective area (A1) of the Doppelhubkolbens is effective. In both cases, accurate and quiet pressure control is possible.

The valve devices (VF, MV / RV1, AVDHK) can be advantageously used for positioning the piston (DHK) of the second piston-cylinder unit to the pressure build-up and pressure reduction for all functions, such as ABS, Brake Assist and Multiplex (MUX) The positioning can be done from the forward stroke (via valves VF, MV / RV1, AVDHK) or the return stroke (via valve AVDHK). Pre-stroke and return stroke positioning can be accomplished by closing all intake valves (EV) and opening the valve devices (VF, MV / RV1, AVDHK). The latter is particularly advantageous for the subsequent pressure build-up and pressure reduction and the multiplex operation.

In systems for recuperation of braking energy, the pedal characteristic should be the same with / without recuperation. This can also be done without WS-piston by a mini-memory in the brake circuit, which receives the displacement volume of the plunger. The valves to the wheel cylinders are in particular closed.

To influence the pedal characteristic can advantageously be performed in two stages, the pedal plunger, in particular two pedal tappets are used in parallel or coaxially, in order to achieve a particularly flat characteristic with small pedal paths). Here, the second stage is effective only after a certain stroke, in particular about 6mm. In addition, the plunger may be provided with a spring which allows a transition function in the pedal characteristic.

Furthermore, for special functions such as Brake Assist and "Blending" i. when hiding the hydraulic pressure of one or both vehicle axles during recuperation, the pedal characteristics are changed by appropriate valve functions.

By these refinements, further improvements of the functions are possible without appreciable costs. The pump solution has the potential for cost and weight reduction, as the ball thread gearbox KGT is eliminated with the torque support of the spindle, since this is no longer necessary.

The braking function should also be possible for autonomous driving in case of failure of the engine and drive. For this purpose, a small additional memory is provided with solenoid valve, which allows for a few brakes nor a brake without brake pedal. The additional storage is preferably arranged (in the illustrated embodiment in the brake circuit BK1) that it is filled during the forward stroke of the piston (DHK).

Advantageously, the memory can also, with appropriate control, for e.g. the clutch operation can be used, which is particularly advantageous in connection with the so-called. Sail operation for saving fuel in manual transmissions. For this purpose, a hydraulic circuit (BK1) via a hydraulic line in which a valve device (46, 50, 54) is arranged to be connected to a hydraulic actuator.

In an embodiment with a pump as a second pressure medium source is provided in particular that the first pressure source has a first working space and a second working space, which are separated by a movable element, in particular piston (SK), and which via a first hydraulic circuit (BK1) and a second hydraulic circuit (BK2) each having a consumer or actuator, in particular a wheel brake, are connected and that the second pressure medium source via hydraulic lines, in which valve means (EA1, EA2) are arranged with the hydraulic circuits (BK1, BK2) or is connected to the working spaces of the first pressure source. In some cases, a hydraulic travel simulator WS is advantageously provided. This is acted upon or actuated in particular by the pressure of the third pressure source.

Further advantageous embodiments or embodiments of the invention and further advantages will become apparent from the following description of the figures with reference to the drawings. The features according to the invention shown and described in connection with the embodiments or embodiments are also useful individually or in other combinations or advantageous, so that protection is sought.

figure description

Show it:

1 a first embodiment of a brake actuation system with a piston-cylinder device as a pressure source;

1a a detailed view of a two-piece pedal plunger;

1b the pedal force characteristic of the execution acc. 1a ;

2 a second embodiment of a brake actuation system with a piston-cylinder device as a pressure source;

3 a third embodiment with a pump as a pressure source;

4 a fourth embodiment with a piston-cylinder device as a pressure source;

5 a fifth embodiment with a hydraulic Wegsimulator; and

5a a sixth version without hydraulic travel simulator.

1 shows a brake actuation system, which is largely the 3 in the DE 10 2014 111 594 corresponds, so that reference is made in this regard. It is a first pressure source, in the form of a piston-cylinder unit (master cylinder) 2 , a second pressure source or piston-cylinder unit 4 with double-stroke piston (DHK) 6 and a third pressure source or piston-cylinder unit 8th with auxiliary piston 10 intended. On the auxiliary piston 10 acts via a force-displacement sensor KWS (described in more detail below) with two pedal travel sensors 12a . 12b an actuating device, in particular brake pedal 1 , The movement of the auxiliary piston can by means of a pedal ram 3 on the piston SK of the first piston-cylinder unit (master cylinder) 2 be transmitted. The double-stroke piston (DHK) 6 The second piston-cylinder unit is by means of an electromechanical drive with motor 14 and ball threaded gear KGT 16 driven. The floating piston SK forms on its front side a working chamber 2a , which are connected via a hydraulic line HL2, which is connected to a hydraulic line HL4, which are part of a brake circuit BK2 and associated with the wheel brakes intake valves EV, which may be arranged in a valve device or a valve block VBL expediently. Another hydraulic line HL1 is part of a further brake circuit BK1 and connects a work space formed on the back of the floating piston SK 2 B with the intake valves EV of the brake circuit BK1. The double-stroke piston (DHK) 6 the second piston-cylinder unit 4 forms two separate working chambers 4a respectively. 4b , wherein the piston has differently sized piston acting surfaces A1 and A1-A2 and wherein the working chambers are connected via hydraulic lines HL4 and HL6 to the hydraulic lines HL1 and HL2. From the working chambers 4a . 4b of the Doppelhubkolbens lead further hydraulic lines, are connected to the check valves S1 and S2, to the reservoir 20 , The check valves act as suction valves during the preliminary stroke (S2) and during the return stroke (S1) of the double-stroke piston. A required electronic control unit (ECU) for the engine and the other electrical components is not shown here.

A non-return valve RV1, which advantageously forms, in particular with a solenoid valve, a normally closed combined check / solenoid valve MV / RV1, is in the working space from the front (left in the figure) 4a arranged the Doppelhubkolbens outgoing hydraulic line HL4. This valve allows a reduction in pressure during the return stroke of the Doppelhubkolbens. Starting from the valve MV / RV1 forms a hydraulic line 24 a connection between the workspaces 4a . 4b of the double-stroke piston, in which a normally closed valve VF is connected. The connecting line opens here (seen from the direction of the work spaces) behind the valve MV / RV1 and before a check valve RV2, which (also not shown) can also be combined with a solenoid valve in the corresponding hydraulic lines. Starting from the line HL4, another hydraulic line HL7 leads to a solenoid valve ESV and from there via the line HL3 to the working space 8a the auxiliary piston-cylinder arrangement 8th ,

In one of the workroom 2a the piston SK of the piston-cylinder assembly (master cylinder) to the reservoir 20 leading hydraulic line HL 10 is another check valve throttle arrangement 32 intended. This is provided for pressure equalization when the vehicle is parked. The check valve causes the temperature equalization pressure equalization by the volume reduction is compensated and the choke causes volume increase in the outflow into the reservoir and replaces a normally open solenoid valve, as in the DE 10 2014 111 594 the applicant to whom reference is made in this regard.

An additional valve AV _DHK is via a hydraulic line HL12 to the rear (in the figure right), a smaller effective area A1-A2 having working space 4b connected to the Doppelhubkolbens. The hydraulic pipe 12 opens here between the working space and the valve RV2 in the line HL6. From valve AVDHK leads another hydraulic line HL 13 to the return of the exhaust valves AV of a brake circuit BK1. Further, a hydraulic line HL14 branches off from this hydraulic line via a check valve throttle arrangement 34 to the workroom 8a the auxiliary piston-cylinder arrangement leads. Another Hydraulic line HL15 branches off from line HL13 and, with the interposition of a valve WA, leads to line HL3 or to the working chamber 8a of the auxiliary piston 10 , When the valve WA is open, the path simulator function is effective. When the valve WA is closed, the brake pedal is locked when the travel simulator is activated and when the ABS function is activated as soon as a pressure reduction occurs. This locks the pedal as it does today with the RF pump as soon as the pressure drops.

It can also be achieved by opening the valve WA volume from the double-stroke piston 6 in the workroom 8a of the auxiliary piston 10 promoted and a pedal movement to warn the driver are generated.

Furthermore, in special cases, such as μ-jump from high to low μ of the auxiliary piston 10 to be moved back via the above control to produce more piston travel and therefore volume for the fallback level when the engine fails after the μ jump and the volume or pressure has to be generated by the driver's foot. This measure can increase the residual volume in this case up to 40%, so that sufficient brake pressure is generated.

For pressure build-up during the pre-stroke of the double-stroke piston (DHK) 6 With the valve VF closed, volume is fed into the brake circuit BK1 via the large effective piston surface A1. At the same time volume is also conveyed to the brake circuit BK2 via the brake circuit BK1 and the floating piston SK. During the return stroke of the double-stroke piston (DHK) 6 is conveyed via the small effective piston area A1-A2 volume in the brake circuit BK2; at the same time volume is conveyed into the brake circuit BK1 via the brake circuit BK2 and the floating piston SK. When the valve VF is open, the volume is conveyed during the preliminary stroke via the small effective piston area (A1-A2). During the return stroke of the double-stroke piston and the closed valve VF, volume is delivered to the brake circuit BK2 via the small effective piston area (A1-A2). A pressure equalization between the brake circuits BK1, BK2 takes place with the valve VF open when the pressure in the brake circuit BK2 is greater than in the brake circuit BK1 or during the return stroke when the pressure in the brake circuit BK2 is greater than that in the brake circuit BK1. A positioning of the Doppelhubkolbens 6 can be done by switching the valve devices VF, MV / RV1 and AVDHK. The positioning can be from the forward stroke (via MV / RV1, VF, AVDHK) or the return stroke (via AVDHK) of the double-stroke piston 6 respectively. When both the valve VF and the valve MV / RV1 and the valve AV _{DHK are} open and all valves EV are closed, positioning of the double-stroke piston can be achieved 6 take place during the return stroke and forward stroke, which is advantageous for the subsequent pressure build-up P _on or pressure reduction P _from and for the MUX mode, since the subsequent advance or return stroke delivery volume is possible.

The pressure reduction P _ab at the end of a braking operation can take place via one or more exhaust valves AV. Here, the pressure reduction from the brake circuit BK2 takes place directly via valve AV in the reservoir 20 and from the brake circuit BK1 via valve VF and valve RV in the brake circuit BK2 and accordingly via valves AV and EV. Here, both brake circuits BK1, BK2 are connected, so that pressure can be reduced from the brake circuit BK1 via the pressure compensation without a valve AV from the brake circuit BK1 is opened. Alternatively, the pressure reduction over the return stroke of the Doppelhubkolbens (DHK) 6 open valves MV / RV2 and AVDHK, which results in a particularly quiet and accurate pressure control, as the dynamics of the Doppelhubkolbens 6 is controllable and no switching noise of the valves AV arise when the pressure is reduced in stages.

With the additional valve AV _DHK , which on return stroke of Doppelhubkolbens the rear pressure chamber of the Doppelhubkolbens with the reservoir 20 connects, the large effective area A1 of the piston is effective, so that even from a high pressure range can be reduced by the large volume of the full pressure over the return stroke. This has the advantage that the brake circuits do not have to be opened via the exhaust valves AV of the wheel brakes and an additional diagnosis of the tightness of these valves is not necessary. This valve circuit is also advantageous in multiplex mode (MUX).

Due to the large volume promotion or volume of the brake circuits for high pressure z. As in fading may be more volume in the brake circuit than the volume to reduce the pressure of the Doppelhubkolbens 6 allows. During pressure reduction, the excess volume must be via a valve AV or more in the reservoir 20 respectively. Then then the pressure reduction via the above-mentioned valve circuit and the Doppelhubkolben 6 respectively. As an alternative, the Doppelhubkolben 6 be repositioned by pre-stroke with closed valves EV as described. In MUX mode, pressure also has to be reduced via valves AV in order, for. B. come in negative μ jump back into the workspace of Doppelhubkolbens for pressure build-up and pressure reduction.

For some special functions such as brake assist, brake circuit failure or "blending" when recuperation, it is advantageous to make the pedal characteristics variable by z. B. the valves EV are closed and the valves ESV and WA are opened. This can be the pedal way be changed with additional pedal force control by pulse width modulation (PWM) operation of the valve WA and / or ESV and force control via the force-displacement simulator KWS, wherein the Differenzwegsignal the two pedal travel sensors 12a . 12b from a defined preload force is proportional to the force. Also can be generated by the corresponding valve circuit (WA closed, MV / RV1 open) with the Doppelhubkolben and the pressure generator DG a corresponding pedal force and a corresponding pedal travel.

To change the normally proportional pressure pedal action can be temporarily switched off by closing the valves EV and SV and opening of the valve ESV this pedal reaction, so that by pulse width modulation of the valves ESV or WA or both the back pressure in the working chamber 8a of the auxiliary piston and in the working chamber 2 B the first pressure source, the pedal reaction can be determined by the force-displacement simulator KWS controlled. Alternatively, the valves EV and SV can be closed and the valve ESV can be opened and the double-stroke piston (DHK) determined by means of pulse width modulation of the valve WA. 6 over pre-stroke or return stroke the dynamic pressure measured by the pressure transmitter DG; the back pressure in turn determines the pedal reaction.

The failure safety of the auxiliary piston circle, in particular the seals of the auxiliary piston 56a is of great importance, as well as the valve WA and the valve of the throttle check valve assembly 34 , In the event of a leak, the brake circuit BK1 also fails in the fallback mode if the engine fails. The seal 55 the auxiliary piston is uncritical, since in the fallback level the auxiliary piston circle is equal to the brake circuit BK1. In normal operation, a strong leak of the seal acts 55 on the pedal force due to the back pressure in front of the open valve WA. This can be avoided by a long guide of the pedal plunger 3 with close fit of a so-called rod seal. The auxiliary piston is a second seal for fail-safety 56 used. Between both seals is a leakage flow channel with a throttle 57 intended. Is the seal 56 leaking, so the leakage flow is limited by the throttle; By detecting the leakage flow can be detected in a special diagnostic cycle, in which at a certain low pressure in the pressure chamber 8a of the auxiliary piston 10 the pressure drop at leak is measured. This diagnostic cycle can also be used to test the valves WA and 34 be applied, preferably after each braking or parking operation.

1a shows a pedal ram 3 formed with a smaller diameter or cross section and as a sleeve, a plunger 3a with a larger cross-section. Accordingly, the pressure acts in the working chamber 2a on both cross sections. Depending on the piston stroke S to S1 only the smaller cross section acts, then the spring engages and acts on the sleeve and the cross section of the plunger 3a , This can represent different characteristics; K3 to S1 and from S2 the steeper characteristic K3a. The transition S1-S2 is realized by the spring.

In the 2 shown brake actuation system largely corresponds to the 1 , so that reference is made in this regard. At the brake actuator after 2 however, only one valve SV1-SV4 is assigned to the wheel brakes. Further, another normally closed valve AVZ is provided, which is arranged in a branching from the hydraulic line HL6 hydraulic line HL16 (BK2), which to the reservoir 20 leads.

Another valve circuit (MV / RV2) should be provided by combining valve RV2 with a solenoid valve such as MV / RV1. This can be reduced directly from this valve and valve AV _DHK pressure from the brake circuit. Thus, the valve AV _{Z is} no longer necessary for pressure reduction P _from .

The valve AV _Z replaces the in 1 drawn valve AV for pressure reduction. In this case, the valve VF must be opened from the brake circuit BK1 again at pressure reduction P _ab . Alternatively, it is also possible to use a second valve AV _Z2 for reducing the pressure P _ab from the brake circuit BK1. This valve arrangement with one or two valves AV _Z is particularly suitable for multiplex (MUX) operation and can be seen as an alternative to the valve arrangement MV / RV2.

3 shows a third embodiment with a pump 40 as a pressure source. The pump 40 is by means of an electric motor-gear arrangement 42 driven. On the suction side, the pump is connected via a hydraulic line HL20 with the exhaust valves AV associated with the wheel brakes, which leads to the return. On the output or pressure side there is a hydraulic connection line HL22 to the two working chambers of the master cylinder and the brake circuits BK1 and BK2. In the branches HL22a and HL22b of this line in each case a normally closed solenoid valve EA1 and EA2 is connected. The pump works in principle as the described piston-cylinder device (Doppelhubkolben). In this case, during the pressure build-up in a direction of rotation via valve EA1 volume in the brake circuit BK1 and via the floating piston SK which moves in the drawing to the left is also conveyed into the brake circuit BK2. Accordingly, via the valve EA2 in the brake circuit BK1 and the floating piston SK, the moved in this case in the drawing to the right, are also promoted in the brake circuit BK1. The pressure is measured and controlled by a pressure transmitter DG. If both valves are open, pressure equalization takes place for both brake circuits BK, which is advantageous in ABS operation. A pressure reduction takes place accordingly by opening one or both valves EA. The pressure is reduced by reversing the direction of rotation of the pump. This means that a suitable pump must be used, eg a gear or vane pump. To perform the ABS function, a pressure equalization takes place in the two brake circuits BK1 and BK2, wherein both valves EA1 and EA2 are open and the floating piston SK remains in position.

In 4 is a fourth embodiment, again with a piston-cylinder device, shown as a pressure source. The 4 corresponds largely to the execution according to 2 , In addition, however, here is a hydraulic line HL26, in which a normally closed solenoid valve 46 is switched, a memory 48 intended. This embodiment is very advantageous for the so-called "autonomous driving" in case of failure of the pressure source (such as double-stroke piston or drive for this).

In autonomous driving, the braking function should be possible even if the engine fails. For this purpose, a small additional reservoir is in front of the solenoid valve ESV 30 arranged, which allows for a few brakes still a brake function without pressing the brake pedal. This memory can also be used with appropriate control eg for a clutch operation, which can be advantageously used in conjunction with the so-called. "Sailing operation" to save fuel in manual transmissions. When the valve ESV is open, volume delivery into the brake circuit BK1 in the fallback level is also possible.

In autonomous driving pressure medium from the memory in case of failure of the drive 48 at open MV 46 led into the brake circuits BK. The memory can be sized small, since the driver has to take over the brakes in error detection and reporting.

Between the solenoid valve 46 and the memory 48 branches off a hydraulic line HL28, which is connected via another normally closed valve 50 to an actuator 52 leads. Between the valve 50 and the actuator 52 branches a line HL30ab, which via a normally closed valve 54 serves as a return to the reservoir. This arrangement is advantageously used when the so-called "sailing" the drive is disconnected because of the friction losses. In manual transmissions, the actuator for clutch control can be used here in a very cost effective manner.

The valve devices for controlling the second pressure source, in particular the Doppelhubkolbens (DHK) 6 , are in 1 or the related description in its comprehensive version, with the valves MV / RV1, MVRV2 and AV _DHK to allow a large number of functions. If fewer functions are sufficient, the valve devices can be reduced accordingly and combined in various combinations with the Doppelhubkolben.

5 shows a further embodiment of the invention, wherein the first pressure source or first piston-cylinder arrangement in contrast to the embodiment according to FIG 1 to 4 not only has a piston SK but another piston DK. Otherwise corresponds to the basic structure of this embodiment with respect to the first pressure source, the second pressure source and the third pressure source, largely the 3 of the DE 10 2014 109 628 the applicant to which reference is made so far.

The line HL4 is via a valve VdK and the hydraulic line HL5 with a third working chamber 2c the first pressure source or piston-cylinder unit 2 connected, the third working chamber 2c behind the piston DK of the first piston-cylinder unit 2 is trained. The hydraulic line HL3 leads from a working chamber 8a the third pressure source 8th optionally to the travel simulator WS and via a valve ESV to the line HL5. In a branch line HL 15 that with the reservoir 20 is connected, a check valve ÜV and a valve WA is arranged.

From the line HL5 also goes from a line HL5 to the reservoir 20 leads.

The from the first working chamber 4a leading hydraulic line HL4 also directly, ie not only via the valve VF, via the check valve RV1, which is preferably designed as a combined magnetic check valve MV / RV1 and the valve EADK connected to the brake circuit BK1. Furthermore, in the from the second working chamber 4b the second pressure source, or the second piston-cylinder unit 4 leading to the second brake circuit BK2 leading hydraulic line HL6 a check valve RV2. The hydraulic lines HL4 and HL6 are via a connecting line 24 , in which the switching valve VF is arranged, connected to each other, the connection of this line is provided with the line HL4 (as seen from the pressure source) behind the check valve RV1 and with the line HL6 in front of the check valve RV2.

Optionally to another, in 5a The illustrated embodiment is a Wegsimulatoreinrichtung WS provided with associated valve devices (in 5 dashed lines framed). This is via a hydraulic line HL3 with the working chamber 8a the third pressure source or piston-cylinder unit 8th connected. A check valve RV3 is arranged in a first branch line HL3a, which starts from the line HL3 and opens between the path simulator WS and a throttle D arranged in a second branch line HL3b. In a third and a fourth outgoing from the line HL3 branch line HL3c and HL3d check valves ÜV or RV4 are arranged.

The pressure build-up occurs in the execution acc. 5 during the forward stroke of the double-stroke piston 6 via the valve MV / RV1 and the line HL4 and the valve VDK and the line HL5 to the working chamber 2c and thus acts on the back of the piston DK. This promotes the corresponding volume in the brake circuit BK1 and the floating piston in the brake circuit BK2. During the return stroke of the double-stroke piston 6 Volume is fed via the valve RV2 or alternatively a combined valve MV / RV2 (not shown) in the line HL6 and thus the brake circuit BK2 and possibly also via the valves VF and EADK in the brake circuit BK1. In this case, a pressure equalization of both brake circuits BK1, BK2 takes place at the same time. The valve VDK is closed. For piston positioning of the piston DK, a valve ADK can be opened, which is arranged in a line HL5a, from the line HL5 to the reservoir 20 leads. In this case, the piston DK until hitting the pedal ram 3 be moved, which is determined by a small pedal movement via the pedal travel sensor. During the subsequent forward stroke, the volume promotion takes place simultaneously in both brake circuits BK1, BK2 again via or through corresponding switching of the valves, as described above. Again, the volume promotion in ABS operation for both brake circuits BK1, BK2 via the described valve circuit. The other functions for the pressure build-up and the pressure reduction correspond to those with respect to 1 . 2 and 3 described functions. Again, that can be done in the 2 shown valve AVz are used. Alternatively, here too a pump can be used as the second pressure source, as in the execution acc. 3 , The valve ESV, which is arranged in the line HL3 or HL4, can here optionally for the supply of pressure medium by means of the third pressure source, in particular the auxiliary piston 8a the piston-cylinder unit 8th be used in the fallback.

5a shows a further embodiment, which in large parts with the 5 However, a hydraulic Wegsimulatoreinrichtung WA is not provided. Belonging to this embodiment valve devices, in particular the valves RV3, ÜV and ESV and the corresponding line sections can be omitted in this embodiment. This simplified embodiment has a separate hydraulic circuit for the third pressure source, in particular piston-cylinder unit (auxiliary piston circle). Thus, the auxiliary piston circle in case of failure of the seal 10a of the auxiliary piston 10 or the valve RV1 and the valve WA has no effect on the braking effect and is thus fail-safe, ie in the event of failure of the third pressure source or auxiliary piston cylinder 8th belonging circle in the fallback level results in no failure of the brake circuit.

As already described, the pedal reaction of the pressure takes place in the working chamber 2c over the pestle 3 , When reaching the control point of the brake booster after about 40% of the pedal travel, the brake pedal is locked by closing the valve WA. This does not work in the fallback level, so that the pedal stroke is transmitted to the piston DK via the plunger. The valve WA is open in normal operation and acts through its throttle effect or pulse width modulation mode (PWM) to damp the bead movement.

Regarding the lengths of the execution 1 compared to the execution after 5 great advantages, since the piston stroke in the execution acc. 1 only about 50% of the pedal stroke is and approximately twice in the overall length. This can be explained by the fact that the double-stroke piston feeds 50% of the volume directly into the brake circuit during the forward stroke and the return stroke. In the fallback mode, the auxiliary piston acts like the piston DK or the double-stroke piston DHK. In the solution acc. 5 the stroke of the piston DK is fully effective twice and the floating piston SK twice to 50%.

LIST OF REFERENCE NUMBERS

1

Actuation device or brake pedal

2

first pressure source or piston-cylinder unit

2a

working chamber

2 B

working chamber

3

pedal pusher

4

second pressure source or piston-cylinder unit

4a

working chamber

4b

working chamber

6

Double Stroke Pistons (DHK)

8th

third pressure source or (auxiliary) piston-cylinder unit

8a

working space

10

auxiliary piston

12a

Pedal travel sensor

12b

Pedal travel sensor

14

engine

16

Ball Threaded Transmission (KGT)

20

reservoir

24

hydraulic line

30

Storage

32

Check valve restrictor assembly

40

Pressure source or pump

42

Electric motor-gear assembly

46

Solenoid valve (normally closed)

48

Storage

50

Solenoid valve (normally closed)

52

actuator

54

Solenoid valve (normally closed)

55

rod seal

56

first seal

56a

second seal

57

Choke in Lzg. to the reservoir

A1

Piston effective area (large)

A1-A2

Piston effective area (small)

AV

outlet valve

AVZ

Solenoid valve (normally closed)

AVDHK

magnetic valve

BK1

brake circuit

BK2

brake circuit

DG

thruster

EA1

Solenoid valve (normally closed)

EA2

Solenoid valve (normally closed)

ECU

electronic control unit

ESV

magnetic valve

EV

intake valve

HL1

hydraulic line

HL2

hydraulic line

HL3

hydraulic line

HL 4

hydraulic line

HL6

hydraulic line

HL7

hydraulic line

HL8

hydraulic line

HL10

hydraulic line

HL12

hydraulic line

hl13

hydraulic line

HL14

hydraulic line

HL15

hydraulic line

HL20

hydraulic line

HL22

hydraulic line

HL22a

hydr. branch line

HL22b

hydr. branch line

MV / RV1

combined check / solenoid valve

RV2

check valve

KWS

Force-displacement sensor

S1

check valve

S2

check valve

SK

floating piston

SV1

magnetic valve

SV2

magnetic valve

SV3

magnetic valve

SV4

magnetic valve

VBL

manifold

VF

Valve (normally open)

WA

Solenoid valve (normally closed)

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 2014/069650 [0002]
• DE 102014111594 [0040, 0042]
• DE 102014109628 [0063]

Claims (31)

Actuating system, in particular for a vehicle brake, with an actuating device, such as a brake pedal, at least one first pressure source ( 2 ) which can be actuated in particular by means of the actuating device and a second pressure source ( 4 ) with an electro-mechanical drive ( 14 . 16 ), whereby the pressure sources ( 2 . 4 ) are each connected via at least one hydraulic line or a hydraulic circuit (BK1, BK2) with at least one consumer or actuator, in particular a wheel brake to supply the consumer or actuator pressure medium and pressurize, and with a first valve means (VBL ) for pressure control, characterized in that by means of the second pressure source ( 4 ), in two movement or actuation directions, which are in particular linear, rotational directions or the forward stroke and return stroke of a piston, at least one hydraulic line or a hydraulic circuit (BK1, BK2), in particular brake circuit, controlled pressure medium can be fed. Actuating system according to claim 1, characterized in that the first pressure source ( 2 ) a first work space ( 2a ) and a second workspace ( 2 B ), which are separated by a movable element, in particular a piston (SK), and the first working space ( 2a ) via a first hydraulic circuit (BK1) and the second working space ( 2 B ) via a second hydraulic circuit (BK2) with at least one consumer or actuator, in particular a wheel brake, are connected, and wherein a first working space ( 4a ) of the second pressure source via a second valve device (MV / RV1), in particular a combined magnetic check valve, with the second working space ( 2 B ) of the first pressure source ( 2 ) and a second workspace ( 4b ) of the second pressure source ( 4 ), via a third valve device (RV2) with the first working space ( 2a ) of the first pressure source ( 2 ) is connected or connectable, and that upon actuation of the second pressure source ( 4 ), in particular the piston (DHK) ( 6 ) in both actuating or moving directions (forward stroke, return stroke) in each case a hydraulic circuit (BK1 or BK2), in particular directly, and a second hydraulic circuit (BK2 or BK1), in particular indirectly, via a movement of the movable element of the first pressure source, in particular of the piston (SK), hydraulic fluid can be supplied to the pressure build-up. Actuating system according to claim 1, characterized in that the first pressure source ( 2 ) a first work space ( 2a ), a second workspace ( 2 B ) and a third workspace ( 2c ), wherein the first working space ( 2a ) from the second workspace ( 2 B ) by a first movable element, in particular piston (SK) and the second working space ( 2 B ) of the first pressure source from the third working space ( 2c ) is separated by a second movable element, in particular piston (DK), and the second working space ( 2 B ) via a first hydraulic circuit (BK1) and the first working space ( 2a ) are connected via a second hydraulic circuit (BK2) to at least one consumer or actuator, in particular a wheel brake, and a first working space ( 4a ) of the second pressure source, in particular via a second valve device (MV / RV1) and a further valve device (VDK), with the third working space ( 2c ) of the first pressure source ( 2 ) and a second workspace ( 4b ) of the second pressure source ( 4 ), in particular via a third valve device (RV2), with the first working space ( 2a ) of the first pressure source ( 2 ) is connected or connectable, that upon actuation of the second pressure source ( 4 ), in particular the piston (DHK) ( 6 ) in both actuating or moving directions (forward stroke, return stroke) in each case a hydraulic circuit (BK1 or BK2), in particular directly, and a second hydraulic circuit (BK2 or BK1), in particular indirectly, via a movement of at least one of the movable elements of the first Pressure source, in particular of the piston (SK, DK), hydraulic fluid can be supplied to the pressure build-up. Actuating system according to one of the preceding claims, characterized in that for the direct supply of pressure medium into a hydraulic circuit or brake circuit of the first working space ( 4b ) of the second pressure source ( 4 ) via a hydraulic line (HL4), in which at least one valve device (RV1 or MV / RV1) is arranged, with a hydraulic circuit or brake circuit, in particular the first brake circuit (BK1) connected or connectable. Actuating system according to one of the preceding claims, characterized in that, in particular for the direct supply of pressure medium in a hydraulic circuit or brake circuit, the second working space ( 4b ) of the second pressure source ( 4 ) via a hydraulic line (HL6), in which at least one valve device (RV2 or MV / RV2) is arranged, with a hydraulic circuit or brake circuit, in particular the second brake circuit (BK2) and in particular via a second hydraulic line ( 24 ) is arranged in the at least one valve device (VF, EADK), with a further brake circuit, in particular the first brake circuit (BK1), connected or connectable. Actuating system according to one of the preceding claims, characterized in that a third pressure source, in particular piston-cylinder unit ( 8th ) is arranged via a hydraulic line (HL3) in the at least one valve device (WA, ESV) is connected to at least one hydraulic circuit, in particular brake circuit. Actuating system according to one of the preceding claims, characterized in that a third pressure source, in particular piston-cylinder unit ( 8th ) is connected via a hydraulic line (HL3) to a hydraulic travel simulator (WS). Actuating system according to one of the preceding claims, characterized in that a piston-cylinder unit ( 4 ) is provided as a second pressure source. Actuating device according to one of the preceding claims, characterized in that a pump ( 40 ), in particular displacement or feed pump, such as gear, vane or radial piston pump is provided as a second pressure source. Actuating system according to one of the preceding claims, characterized in that the two working spaces ( 4a . 4b ) of the second pressure source ( 4 ), in particular the piston-cylinder unit, via a hydraulic line ( 24 ), in which a fourth valve device (VF) is arranged, are interconnected or connectable. Actuating system according to one of the preceding claims, characterized in that the pressure reduction in a consumer or actuator, in particular a wheel brake volume from a first hydraulic circuit or brake circuit (BK1) indirectly via valve means (VF and RV2 or MV / RV2), in a second hydraulic circuit, in particular brake circuit (BK2) and from the second hydraulic circuit (BK2) directly via a valve device (AV) in a reservoir ( 20 ) is eligible. (Pressure reduction variant A) Actuating system according to one of the preceding claims, characterized in that the pressure reduction in a consumer or actuator, in particular a wheel volume from a first brake circuit (BK1) via the second pressure source, in particular return stroke of the Doppelhubkolbens (DHK) and a Valve device (RV1 or MV / RV1) and from a second brake circuit (BK2) via valve means (RV2 or MV / RV2) from a second brake circuit (BK2) is conveyed. (Pressure reduction variant B) actuating system according to one of the preceding claims, characterized in that in particular for reducing the pressure in a consumer or actuator, in particular wheel brake, a fifth valve device (AVDHK) is provided, which is arranged in a hydraulic line (HL12, R), a second workspace ( 4b ) of the second pressure source ( 4 ), in particular a piston-cylinder unit, with a reservoir ( 20 ), is arranged. Actuating system according to one of the preceding claims, characterized in that for pressure reduction volume from a first brake circuit (BK1) via the second pressure source, in particular return stroke of the movable element or Doppelhubkolben (DHK) of the second pressure source via a valve device (in particular RV1 or MV / RV1) in a first working space (in particular working space 4a ) of the double-stroke piston (DHK) and volume from a second working space (in particular working space 4b ) of the Doppelhubkolbens (DHK) via a valve device (in particular AV DHK) is conveyed into a reservoir and that volume from a second brake circuit (BK2) via the first pressure source, in particular by movement or displacement of at least one piston (SK, DK) as a Piston-cylinder unit formed first pressure source is funded. (Pressure reduction variant C) Actuating system according to one of the preceding claims, characterized in that the pressure reduction in a consumer or actuator, in particular a wheel brake volume from a first brake circuit (BK1) via a valve device (VF and AVDHK) and from a second brake circuit (BK2) via another Valve device (R2 or MV / RV2 and AVDHK) is conveyed. (Pressure reduction variant D) Actuating system according to one of the preceding claims, characterized in that for pressure reduction from the brake circuits (BK1, BK2) at least one brake circuit associated sixth valve means (AVZ1, AVZ2) is provided, in a hydraulic connecting line (HL16, HL17), which the brake circuit (BK1, BK2) with the reservoir ( 20 ), is arranged. Actuating device according to one of the preceding claims, characterized in that valve devices (VF, MV / RV1, AVDHK) for positioning the piston ( 6 ) of the piston-cylinder unit ( 4 ) are provided during the preliminary stroke (VF, MV / RV1, AVDHK) and / or during the return stroke (AVDHK). Actuating system according to one of the preceding claims, characterized in that a small memory ( 30 ) with return spring in a brake circuit (BK1), in particular call place, is arranged in order for the pedal characteristic for recuperation of the braking energy, the displacement volume of the pedal plunger ( 3 ). Actuating system according to one of the preceding claims, characterized in that the first pressure source ( 2 ) at least two workspaces ( 2a . 2 B ) which are each separated by a movable element, in particular pistons (SK, DK), and which are separated by a first hydraulic circuit (BK1) and a second hydraulic circuit (BK2) are each connected to a consumer or actuator, in particular a wheel brake, and that the second pressure medium source ( 40 ) via hydraulic lines (HL22a, HL22b), in which valve devices (EA1, EA2) are arranged, with the hydraulic circuits (BK1, BK2) or the work spaces ( 2a . 2 B ) of the first pressure source ( 2 ) connected is. Actuating device according to one of the preceding claims, characterized in that a hydraulic circuit (BK1) via a hydraulic line (HL26, HL28), in which a valve device ( 46 . 50 . 54 ) is arranged with a hydraulic actuator ( 52 ) connected is. Actuating device according to claim 20, characterized in that in the hydraulic line (HL26, HL28) a memory device ( 48 ) is provided. Actuating system according to one of the preceding claims, characterized in that for changing the pedal reaction, this can be temporarily switched off by means of valve devices, in particular by closing the valves (EV or SV) and opening the valve (ESV), so that by pulse width modulation of the valve (ESV) and / or the valve (WA) the back pressure in the third piston-cylinder unit ( 8th ) determines the pedal reaction. Method for operating an actuating system according to one of the preceding claims, characterized in that by means of the second pressure source ( 4 ), in two movement or actuation directions, which are in particular linear, rotational directions or the forward stroke and return stroke of a piston, at least one hydraulic line or a hydraulic circuit (BK1, BK2), in particular brake circuit, controlled pressure medium is supplied. A method according to claim 23, characterized in that a pressure medium supply or a pressure build-up takes place indirectly in at least one brake circuit, via a pressure medium supply from the second pressure source ( 4 ) to the first pressure source ( 2 ), whereby a movable element, in particular piston (SK, DK), the first pressure source ( 2 ) is moved and the brake circuit pressure medium is thereby supplied. A method according to claim 23 or 24, characterized in that the pressure reduction in a consumer or actuator, in particular a wheel brake volume from a first hydraulic circuit or brake circuit (BK1) indirectly via valve means (VF and RV2 or MV / RV2), in a second hydraulic circuit, in particular brake circuit (BK2) and from the second hydraulic circuit (BK2) directly via a valve device (AV) in a reservoir ( 20 ). (Pressure reduction variant A) Method according to one of claims 23 to 25, characterized in that for the pressure reduction in a consumer or actuator, in particular a wheel volume from a first brake circuit (BK1) via the second pressure source, in particular return stroke of the Doppelhubkolbens (DHK) and a valve device (RV1 or MV / RV1) and from a second brake circuit (BK2) via valve devices (RV2 or MV / RV2) from a second brake circuit (BK2) is promoted. (Pressure reduction variant B) Method according to one of the preceding claims 23 to 26, characterized in that for pressure reduction volume from a first brake circuit (BK1) via the second pressure source, in particular return stroke of the movable element or Doppelhubkolben (DHK) of the second pressure source via a valve device (in particular RV1 or MV / RV1) into a first working space (in particular working space 4a ) of the double-stroke piston (DHK) and volume from a second working space (in particular working space 4b ) of the Doppelhubkolbens (DHK) via a valve device (in particular AV DHK) is conveyed into a reservoir and that and that volume of a second brake circuit (BK2) via the first pressure source, in particular by movement or displacement of at least one piston (SK, DK) a designed as a piston-cylinder unit first pressure source is promoted. (Pressure reduction variant C) Method according to one of the preceding claims 23 to 27, characterized in that for pressure reduction in a consumer or actuator, in particular a wheel brake volume from a first brake circuit (BK1) via a valve device (VF and AVDHK) and from a second brake circuit (BK2) via a further valve device (R2 or MV / RV2 and AVDHK) is promoted. (Pressure reduction variant D) Method according to claim 23 or 28, characterized in that the first pressure source ( 2 ) a first work space ( 2a ) and a second workspace ( 2 B ), which are separated by a movable element, in particular piston (SK), and the first working space ( 2a ) via a first hydraulic circuit (BK1) and the second working space ( 2 B ) are connected via a second hydraulic circuit (BK2) to at least one consumer or actuator, in particular a wheel brake, and in that a first working space (BK2) 4a ) of the second pressure source ( 4 ) via a second valve device (MV / RV1) with the second working space ( 2 B ) of the first pressure source ( 2 ) and a second workspace ( 4b ) of the second pressure source ( 4 ), via a third valve device (RV2) with the second working space ( 2a ) of the first pressure source ( 2 ) and that upon actuation of the second pressure source ( 4 ) in the two actuation or Movement directions, in particular during the forward stroke and the return stroke of the piston ( 6 ), in each case a first hydraulic circuit (HL1, BK1), in particular directly, and a second hydraulic circuit (HL2, BK2), in particular indirectly, hydraulic fluid for pressure build-up in a consumer or actuator, in particular a wheel brake is supplied. Method according to one of claims 23 to 29, characterized in that the two working spaces ( 4a . 4b ) of the second pressure source ( 4 ) via a hydraulic line ( 24 ), in which a fourth valve device (VF) is arranged, are connected to one another, and that for pressure reduction during the return stroke of the piston ( 6 ) the pressure source ( 4 ) Pressure medium from a brake circuit (BK1) via a second valve device (MV / RV1)), which is in particular a combined magnetic check valve, the first working space ( 4a ) is supplied, and that via the fourth valve means (VF) pressure medium from the second working space ( 4b ) the pressure source ( 4 ) the first workspace ( 4a ) is supplied. Method according to one of claims 23 to 30, characterized in that the pressure reduction in a consumer or actuator, in particular a wheel brake, during the return stroke of the piston ( 6 ) the pressure source ( 4 ) via a fifth valve device (AVDHK), which in a hydraulic line, which the second working space ( 4b ) of the second pressure source ( 4 ), in particular piston-cylinder unit, with the reservoir ( 20 ), is arranged, pressure medium from the second working space ( 4b ) in the reservoir ( 20 ) is discharged, in particular the pressure reduction from a brake circuit (BK1) via the second valve device (MV / RV1 in the working space ( 4a ) he follows. Method according to one of claims 23 to 31, characterized in that for pressure reduction from a brake circuit (BK1), a hydraulic connection via a fourth valve means (VF) and in particular via a third valve means (RV2) is provided. Method according to one of claims 23 to 32, characterized in that a positioning of the piston ( 6 ) of the piston-cylinder unit ( 4 ) by means of switching valve devices (VF, MV / RV1, AVDHK) during the forward stroke or return stroke (AVDHK) of the piston (FIG. 6 ) he follows. Method according to one of claims 23 to 33, characterized in that the pedal reaction is temporarily changed, in particular by closing the valves (EV or SV) and opening the valve ESV, so that by pulse width modulation of the valve ESV or the valve WA or both the Back pressure in the first piston-cylinder unit ( 2 ) and in the third piston-cylinder unit ( 8th ) determines the pedal reaction. Method according to claim 23 to 34, characterized in that the first pressure source ( 2 ) a first work space ( 2a ), a second workspace ( 2 B ) and a third workspace ( 2c ), wherein the first working space ( 2a ) from the second workspace ( 2 B ) by a first movable element, in particular piston (SK) and the second working space ( 2 B ) from the third workspace ( 2c ) is separated by a second movable element, in particular piston (DK), and the second working space ( 2 B ) via a first hydraulic circuit (BK1) and the first working space ( 2a ) are connected via a second hydraulic circuit (BK2) to at least one consumer or actuator, in particular a wheel brake, and a first working space ( 4a ) of the second pressure source via a second valve device (MV / RV1) in particular combined magnetic check valve and a further valve device (VDK), with the third working space ( 2c ) of the first pressure source ( 2 ) and a second workspace ( 4b ) of the second pressure source ( 4 ), via a third valve device (RV2) with the first working space ( 2a ) of the first pressure source ( 2 ) is connected or connectable, and that upon actuation of the second pressure source ( 4 ), in particular the piston ( 6 ) in a direction of movement (forward stroke) a first hydraulic circuit (BK1) and a second hydraulic circuit (BK2), in particular indirectly via a movement of the movable element, in particular piston (DK, SK), hydraulic fluid is supplied to the pressure build-up. Method according to one of claims 23 to 35, characterized in that upon actuation of the second pressure source ( 4 ), in particular the piston ( 6 ) in a direction of movement (return stroke) a first hydraulic circuit (BK1) and a second hydraulic circuit (BK2), in particular directly hydraulic fluid is supplied to the pressure build-up.

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