EP2760716A1

EP2760716A1 - Master brake cylinder for a vehicle brake system and method for operating a master brake cylinder

Info

Publication number: EP2760716A1
Application number: EP12745692.9A
Authority: EP
Inventors: Laurent Lhuillier; Antony Auguste; Matthias Kistner; Takeshi Kaneko; Tim ALBERT; Bastien Cagnac
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2011-09-30
Filing date: 2012-08-08
Publication date: 2014-08-06
Also published as: CN103826946B; US20150158475A1; WO2013045161A1; JP5946535B2; KR20140069046A; JP2014531364A; US9643582B2; CN103826946A; DE102011083896A1

Abstract

The invention relates to a master brake cylinder (10) for a vehicle brake system, comprising a first filling volume (12) that can be filled with liquid, the first parameter of which is variable by adjusting at least a first piston wall (14), a second filling volume (16) that can be filled with liquid, the second parameter of which is variable by adjusting at least a second piston wall (18), and a valve device (20), characterized in that the first filling volume (12) is connected to the second filling volume (16) via the valve device (20) such that during the control of the valve device (20) in a first valve state a common first pressure chamber pressure is present in the first filling volume (12) and the second filling volume (16). The invention further relates to a method for operating a master brake cylinder (10).

Description

Description title

Master brake cylinder for a brake system of a vehicle and method for operating a master cylinder

The invention relates to a master cylinder for a brake system of a vehicle. Likewise, the invention relates to a brake device for a brake system of a vehicle and a brake system for a vehicle. Furthermore, the invention relates to a method for operating a master cylinder.

State of the art

In WO 2009/121645 A1 a hydraulic vehicle brake system is described. The master brake cylinder of the hydraulic vehicle brake system comprises a first

Pressure chamber and a second pressure chamber. In addition, the master brake cylinder has an integrated pedal travel simulator 22 at an end that widens toward the brake pedal, the volume of which can be filled with brake fluid being hydraulically connected to a brake fluid reservoir via a simulator valve. That with

Brake fluid fillable volume of the pedal travel simulator and the adjacent first pressure chamber are of a trained as a stepped piston rod and

Limited simulator piston.

DISCLOSURE OF THE INVENTION The invention provides a master brake cylinder for a brake system of a vehicle having the features of claim 1, a brake device for a brake system of a vehicle having the features of claim 6, a brake system for a vehicle with the

Features of claim 1 1 and a method for operating a

Master cylinder with the features of claim 12. Advantages of the invention

The invention makes possible a master brake cylinder whose first pressure chamber in a first operating mode of the master brake cylinder can comprise at least a first filling volume and a second filling volume, wherein each of the two filling volumes can be varied in size via an adjustment of the piston wall assigned to it. However, the master brake cylinder can also be operated in a second operating mode, in which the first pressure chamber comprises at least the first filling volume, while in the second filling volume there is a reservoir pressure, in particular the atmospheric pressure. This can also be done as an optional connection and disconnection of the second

Rewrite filling volume. Thus, the first pressure chamber of the advantageous

Master cylinder in its size in addition to an adjustment of the

Filling volume limiting piston walls also variable on the switching on and off of the second filling volume.

As will be explained in more detail below, by switching off the second

Filling volume, or the setting of the reservoir pressure in the second filling volume, the braking are amplified in the first pressure chamber of the master cylinder. Thus, due to the reduction of the available volume of the first pressure chamber at a given braking force (driver braking force), increased brake pressure results. This can also be referred to as an increase in the braking force-brake-pressure ratio by reducing the Einbremsvolumens the first pressure chamber. The present invention thus enables a switching of the hydraulic

Translation (Einbremskraft- and pressure ratio), by means of which in case of failure of a brake booster device with a given pedal force an increased pressure build-up in the Einbremsvolumen the first pressure chamber can be achieved. In this way, a higher delay for fast braking of a vehicle with a comparatively low driver braking force is effected. For example, by switching off the second filling volume despite a failure of the

Brake booster device at a driver braking force (pedal force) of 500N at least a delay of 2.44 m / s ² can be achieved. By means of the invention, in addition, the master cylinder without regard to the failure of the

Brake servo device still achievable delay are designed. In spite of the ability to connect and disconnect the second filling volume, there is still an advantageous feeling of brake actuation (pedal feel) and a good volume budget

Ensures master cylinder.

A further advantage of the present invention is that a deceleration of at least 6.44 m / s ² at a driver braking force of 500N can also be achieved with a withdrawn ignition key for a large number of vehicles on the market. The delay can also (without a no longer required awakening) at a

"sleeping" braking system can be achieved. In addition, the complexity of many electric brake boosters and the systems equipped therewith can be reduced by means of the present invention.

The present invention can be easily accommodated as an additional component in a (hydraulic) brake system. The invention provides an advantageous electrically or mechanically switchable fallback level in a

Functional impairment of a brake booster device, such as in case of failure of the brake booster device. It should be understood, however, that the utility of the present invention is not limited solely to compensating for the degradation of the brake booster device.

Brief description of the drawings

Further features and advantages of the present invention will be explained below with reference to the figures. Show it:

Fig. 1 is a schematic representation of a first embodiment of the

Master cylinder; Fig. 2 is a schematic representation of a second embodiment of the

Master cylinder;

3a and 3b a schematic overall view and an enlarged

Partial view of an embodiment of the brake system; 4 is a schematic representation of a first embodiment of the braking device;

Fig. 5 is a schematic representation of a second embodiment of the

Braking device; and

6 is a flow chart illustrating an embodiment of the invention

Method for operating a master cylinder.

Embodiments of the invention

Fig. 1 shows a schematic representation of a first embodiment of the

Brake master cylinder.

The schematically illustrated in Fig. 1 master cylinder 10 is in one

Can be used braking system of a vehicle. The master cylinder 10 has a first filling volume 12 which can be filled with liquid and whose first size can be varied by adjusting at least one first piston wall 14. In addition, the

Master cylinder 10 a liquid-filled second filling volume 16, the second size is also variable by adjusting at least one second piston wall 18. The first filling volume 12 is connected via a valve device 20 to the second filling volume 16 (hydraulically) in such a way that, when controlling the

Valve device 20 in a first valve state, a common first

Pressure chamber pressure in the first filling volume 12 (as a first internal pressure) and in the second filling volume 16 (as a second internal pressure) is present.

The second filling volume 16 can via the valve device 20 in such a way

Be connected / be attached to the brake fluid reservoir 22, that in a control of the valve device 20 in a second

Valve state present in the brake fluid reservoir 22 reservoir pressure in the second filling volume 16 is present. During the control of the valve device 20 into the second valve state, a first internal pressure deviating from the reservoir pressure can be controlled in the first filling volume 12 in this case. The reservoir pressure of the brake fluid reservoir 22 may in particular be the atmospheric pressure. The master brake cylinder 10 thus has a first pressure chamber, which in the control of the valve device 20 in the first valve state, at least the first

Filling volume 12 and the second filling volume 16 includes. In contrast, the first pressure chamber of the master cylinder 10 in the control of the valve device 20 in the second valve state at least the first filling volume 12, wherein in the first filling volume 12 (by means of the adjustment of the first piston wall 14) one of the (present in the second filling volume 16) Reservoir pressure deviating first internal pressure is einsteuerbar. The control of the valve device 20 in the first valve state or in the second valve state thus causes a connection or disconnection of the second filling volume 16 to the first pressure chamber of the master cylinder 10. By this switching on or off of the second filling volume 16, the volume of the first pressure chamber independently be set / varied by a position / position of the piston walls 14 and 18. This can also be referred to as setting the Einbremsvolumens the first pressure chamber, wherein in a presence of the valve device 20 in the first valve state, the Einbremsvolumen the first pressure chamber (at least) the two filling volumes 12 and 16, while in the presence of the valve device 20 in the second Valve state the Einbremsvolumen the first pressure chamber of the second

Filling volume 16 is separated.

By switching off the second filling volume 16, or the separation of the

Einbremsvolumens the first pressure chamber of the second filling volume 16, a Einbremskraft brake pressure translation (at least the first pressure chamber) with respect to a translation of the first filling volume 12 limiting first piston wall 14 exerted braking force can be increased in a built-up in the first pressure chamber brake pressure. Thus, after switching off the second

Befüllvolumens 16 are already constructed by means of a relatively small force exerted on the first piston wall 14 braking force, a comparatively large brake pressure. By switching off the second filling volume 16 is thus from the

Braking force / braking force resulting delay can be increased. By increasing the Einbremskraft brake pressure translation (at least the first pressure chamber), for example, a functional impairment of a brake booster

be compensated. However, the use of the master cylinder 10 described here is not limited to compensating for a failure of a brake booster. Optionally, the master cylinder 10 may also include a second pressure chamber 24 into which a floating piston member 26 at least partially so

it is adjustable that a second brake pressure present in the second pressure chamber 24 is variable. It should be understood, however, that the formability of the master cylinder 10 described herein is not limited to a tandem master cylinder. Thus, the master cylinder 10 may also comprise only a single (first) pressure chamber whose Einbremsvolumen means of the valve device 20 can be fixed / varied. The brake fluid reservoir 22, to which the second filling volume 16 can be connected via the valve device 20, can be, for example, a central brake fluid reservoir 22, with which the first filling volume 12, the second filling volume 16 and / or the second pressure chamber 24 via one

Schnüffelbohrung 28 are hydraulically connected. Likewise, a second

Brake fluid reservoir 22 are used for selectively setting the reservoir pressure in the second filling volume 16.

The limiting the first filling volume 12 and the second filling volume 16

Piston walls 14 and 18 may be formed in an advantageous embodiment of a common piston member 30. The common piston member 30 is preferably formed in this case as a stepped piston. The piston component 30 may have on a center end of the master cylinder 10 aligned inner end a first piston portion 30a with a first diameter d1 perpendicular to an adjustment direction 31 of the piston member 30 which is smaller than a second diameter d2 perpendicular to the adjustment direction 31 of the first

Piston portion 30 a adjacent second piston portion 30 b of the piston member 30 is.

Between the first piston portion 30a of the formed as a stepped piston

Piston member 30 and an adjacent wall of the master cylinder 10, a sealing element 32, such as a sealing ring and / or a lip seal may be arranged. In this way, an undesirable fluid exchange between the two filling volumes 12 and 16 along the designed as a stepped piston

Piston component 30 preventable. As an alternative or supplement thereto, seepage of liquid from the master cylinder 10 may occur via an intermediate between the second piston portion 30b and the adjacent wall of the master cylinder 10 arranged sealing element 32, which is also a sealing ring and / or a

Lip seal can be prevented.

When the piston component 30 is designed as a stepped piston, the shape of the filling volumes 12 and 16 is preferably adapted to the stepped piston. For example, a perpendicular to the adjustment direction 31 of the piston member 30 aligned first inner diameter di1 of the first filling volume 12 to the first diameter d1 of the first piston portion 30a and a double ring thickness of the sealing element 32 and / or aligned perpendicular to the adjustment direction 31 second

Inner diameter di2 of the second filling volume 16, the second diameter d2 of the second piston member 30 and the double ring thickness of the sealing element 32nd

correspond.

It should be noted, however, that the formation of the piston walls 14 and 18 bounding the filling volumes 12 and 16 to a common piston component 30 is merely optional. Likewise, the first piston wall 14 may be formed on a first piston (not shown) which is adjustable with the second piston wall 18 independently of a separately formed second piston (not shown). The shape of the master cylinder 10 is selectable with a great design freedom. The formation of two different inner diameter di1 and di2 on the

Master cylinder 10 is thus to be interpreted as an example only.

The valve device 20 may be formed directly on the master cylinder 10 in a line connecting the two filling volume 12 and 16 / hydraulic connection. As an alternative to this, however, the valve device 20 can also be a component of a brake circuit 34, via which two filling volumes 12 and 16 are hydraulically connected via at least one feed opening 38 to at least one wheel brake caliper 36. However, if a hydraulic connection between the two filling volumes 12 and 16 is formed on the master cylinder 10, can on the formation of a

Feeding 38 are omitted for connecting one of the two filling volume 16 to the first brake circuit 34.

It should be noted that the applicability of the described here

Master cylinder 10 is not limited to a braking system with a certain number of

Brake circuits 34 and 40 or a predetermined number of Radbremszangen 36 and 42 is limited. Instead, the number of brake circuits 34 and 40 and the

Wheel brake calipers 36 and 42 are adapted to the intended use of the braking system. In an advantageous embodiment, the valve device 20 is designed so that it is present in the second valve state without current, while the valve device 20 is controllable via a current from the second valve state into the first valve state. One can also rewrite this so that the valve device 20 via a current in the first valve state and a cancellation of the energization in the second

Valve state is controllable. Thus, the valve device 20 is controlled in a simple manner.

The master cylinder 10 may be operated in conjunction with a brake booster 46 in a brake / brake system. An actuator device 44 of the brake booster device 46 in this case is preferably designed to apply a brake assist force Fu to an amplifier body 48 of the brake booster

Brake booster device 46 exercise so that by means of the adjustment of the booster body 48, the brake assist force Fu on the at least one piston of the piston walls 14 and 18 is transferable. In this way, in addition to the via a linkage 50 of a (not shown) brake actuator transmitted driver braking force Fb also with the brake assist force Fu in the

Brake master cylinder 10 are braked. This causes a relief of the driver when braking his vehicle. Preferably, the currentless present in the second valve state

Valve alignment 20 in a (not shown) common circuit with the actuator device 44 of the brake booster device 46 to be involved. In this case it is ensured that if the power supply is impaired

Actuator 44, the valve device 20 (automatically) in the second valve state is controllable. This causes an (automatic) shutdown of the second filling volume 16, or an (automatic) separation of the second filling volume 16 from the first pressure chamber, with an impairment of the power supply of the actuator 44. In this way, the Einbremskraft brake pressure transmission ratio with respect to a translation one on the first filling volume 12 limiting first

Piston wall 14 exerted braking force in a built-up in the first pressure chamber brake pressure (automatically) steigerbar. As an alternative or supplement to an integration of the valve device 20 in a common circuit with the actuator 44, the power supply of the present in the second valve state valve 20 can be interrupted even if the brake assist force Fu, or in a functional impairment of the brake booster device 46 , This causes the above-described high Einbremskraft-brake pressure transmission ratio of the first pressure chamber of the master cylinder 10. Thus, the driver even with a relatively low driver braking force Fb still a sufficiently high

Brake pressure in the at least one wheel brake cylinder 36 and 42 cause.

Fig. 2 shows a schematic representation of a second embodiment of the

Brake master cylinder. The brake device / brake system shown schematically in FIG. 2, or the master brake cylinder 10 contained therein, has a pressure relief valve 52 as a supplement to the previously described components, via which the valve device 20 is hydraulically connected to the brake fluid reservoir 22. The pressure relief valve 52 is aligned so that a fluid displacement is prevented from the brake fluid reservoir 22 via the pressure relief valve 52 to the valve device 20 even at a relatively high pressure, while the pressure relief valve 52 opens at a relatively high pressure on the output side of the valve device 20.

By means of the pressure relief valve 52, the second filling volume 16 can be used at the beginning of a brake operation in the backup mode. That's the way it is

Braking volume also increased. Likewise, a delay achievable with a maximum pedal travel can be increased.

3a and 3b show a schematic overall view and an enlarged partial view of an embodiment of the brake system.

The brake system shown schematically in FIG. 3 a has the master brake cylinder 10, the brake fluid reservoir 22, at least one brake circuit 34 with at least one wheel brake caliper 36, the brake booster device 46 and an ESP device 54. On the linkage 50 of the brake booster device 46, a brake operating member 56, such as a brake pedal, is arranged. Furthermore 3a shows a vehicle battery 58 is shown schematically, by means of which the actuator device 44 of the brake booster device 46 and the ESP device 54 are supplied with power. A section 60 of the schematically reproduced

Brake circuit 34, which is located between the master cylinder 10 and the ESP device 54, is shown enlarged in Fig. 3b.

As can be seen with reference to FIG. 3 b, the valve device 20 can also be arranged at a distance from the master brake cylinder 10 in the at least one brake circuit 34. For example, the valve device 20 may be arranged between a first line 62 leading to the second filling volume 16 and a second line 64 leading to the ESP device 54. A third line 66, which connects the first filling volume 12 with the ESP device 54, can open into the second line 64. About a partially reproduced fourth line 68, the

Valve means 20 may be connected to the brake fluid reservoir 22. Likewise, another reservoir may be connected to the fourth conduit 68.

Even with a spaced from the master cylinder 10 arrangement of

Valve device 20, a failure of the brake booster device 46 can still be compensated by means of a separation of the second filling volume 16 of the first pressure chamber, that by means of a applied as a driver brake force Fb comparatively low Einbremskraft still a sufficiently high braking pressure in the separated from the second filling volume 16 first pressure chamber effected is.

It should be noted that for the valve device 20 also a conventional way already existing in the brake system component, such as at least one valve of the ESP device 54, (co-) can be used. Likewise, the valve device 20 can additionally be used by the ESP device 54. Through this multifunctional design of the valve device 20 manufacturing costs can be reduced.

In addition, for the advantageous brake system with a selectively adjustable Einbremsvolumen the first pressure chamber, a standard / conventional master cylinder 10 can be used. For realizing the reproduced in Figs. 3a and 3b brake system and a cost-effective master cylinder is used. FIG. 4 shows a schematic representation of a first embodiment of the invention

Braking device.

The brake device shown schematically in Fig. 4 is used in a brake system of a vehicle. The brake device has the master cylinder 10 and the

Brake booster device 46 with the components already described above. Optionally, the brake device may also include a brake fluid reservoir 22.

In the brake apparatus shown schematically in FIG. 4, the valve device 20a and 20b is arranged / connected to the booster body 48 of the brake booster device 46 such that the valve device 20a and 20b are connected by means of the

Amplifier body 48 at least from the first valve state in the second

Valve status is mechanically switchable. Optionally, the valve device 20a and 20b may also be mechanically switchable by means of the booster body 48 from the second valve state to the first valve state. The amplifier body 48 can be understood to mean a component of the brake booster device 46 which is connected to the brake booster device 46 by means of the actuator device 44

provided brake assist force Fu is adjustable. The actuator device 44 may comprise, for example, a hydraulic or electromechanical device. The transmission of the brake assist force Fu from the actuator device 44 to the

Amplifier body 48 can be made via at least one intermediate component. Likewise or alternatively, the switching of the valve device 20a and 20b, at least from the first valve state to the second valve state by the booster body 48, can also be carried out via at least one intermediate component.

For example, for switching the valve device 20a and 20b, at least from the first valve state, the booster body 48 is arranged on the valve device 20a and 20b such that when the booster body 48 is present in one

Initial position, the valve means 20a and 20b is present in the second valve state, while an adjustment of the booster body 48 from the initial position by a Mindestverstellweg causes the control of the valve means 20a and 20b from the second valve state to the first valve state. The initial position of the booster body 48 in this case is preferably a position in which the booster body 48 at a driver brake force Fb equal to zero and / or

Brake assist force Fu is equal to zero. In this way, at a functional impairment of

Bremskraftverstärkervorrichtung 46, which is usually a presence of the

Amplifier body 48 in its initial position (despite a driver braking force not equal to zero) causes / triggers, (automatic) controlling the valve means 20a and 20b in the second valve state effected. The mechanical switchability of the valve device 20a and 20b in the second valve state by means of the arresting of the amplifier body 46 in its initial position thus effected in a loss of

Brake assist force Fu (automatically) an advantageously small Einbremsvolumen the first pressure chamber.

In contrast, in a usually on the (full) functionality of the

Brake Booster 46 attributable to the amplifier body 48 from its initial position ensures the (automatic) presence of the valve means 20a and 20b in the first valve state. In a guaranteed

Functioning of the brake booster 46, the first pressure chamber thus (automatically) on an advantageously large Einbremsvolumen.

The valve device 20a and 20b may be assigned at least one pressure-exerting component 74 of the booster body 48. In this case, a displacement of the amplifier body 48 out of its starting position can bring about co-adjustment of the at least one pressure-exerting component 74. By Mitverstellen the at least one Druckausübkomponente 74, a mechanical pressure / a mechanical force on at least one (not outlined) switching mechanism of the valve means 20a and 20b be exercised so that the at least one (not outlined) switching mechanism of the valve means 20a and 20b is mechanically switched ,

The advantageous mode of operation of the mechanically switchable valve device 20a and 20b can also be described in such a way that the amplifier body 48 moves parallel to the piston component 30, d. H. at a constant distance a (equal to a minimum distance) to the piston member 30, in the first valve state.

In contrast, a decreasing pressure and / or force exerted on the valve means 20a and 20b by the at least one Druckausübkomponente 74 switching the valve means 20a and 20b in the second valve state. In the schematically illustrated in Fig. 4 embodiment, the embodiment comprises

Valve means 20a and 20b, two mechanically switchable valve units 20a and 20b. A first valve unit 20a is arranged in a hydraulic connection 70 between the first filling volume 12 and the second filling volume 16. A second

Valve unit 20b is formed in a further hydraulic connection 72 between the second filling volume 16 and the brake fluid reservoir 22. Each of the two valve units 20a and 20b is each a Druckausübkomponente 74 of

Amplifier body 48 assigned.

Specifically, the first valve state of the valve means 20a and 20b formed of the valve units 20a and 20b may be defined by the first one

Valve unit 20a is present in a first flow state, while the second

Valve unit 20b is in a second blocking state. In addition, in the second valve state, the first valve unit 20a may be in a first blocking state and the second valve unit 20b may be in a second throughflow state. In this case, by means of the outward displacement of the amplifier body 48 from its starting position and the co-displacement of the at least one pressure-exerting component 74, the first

Valve unit 20a in the first blocking state and the second valve unit 20b in the second Durchströmzustand be mechanically switchable. Moving the

Amplifier body 48 parallel to the piston member 30 (distance a equal to the minimum distance) controls the first valve unit 20a from the first flow-through state to the first blocking state and the second valve unit 20b from the second blocking state to the second flow-through state. In contrast, a declining

Applying pressure to the two valve units 20a and 20b (distance a greater than the minimum distance), switching back of the first valve unit 20a from the first blocking state to the first flow state and the second valve unit 20b from the second flow state to the second blocking state.

It should be noted, however, that the mechanically switchable design of the valve device 20a and 20b is not limited to their equipment with two separate valve sub-units 20a and 20b.

Fig. 5 shows a schematic representation of a second embodiment of the

Braking device.

The braking device shown schematically in FIG. 5 has a valve device 20, which is at least partially co-adjustable with the piston component 30 and connected to the booster body 48 via a connecting component 76 in such a way that the Valve device 20 by means of a relative movement of the amplifier body 48 in relation to the piston member 30 is mechanically switchable at least between the first valve state and the second valve state. For this purpose, the valve device 20 has a housing component which is designed to be adjustable with the piston component 30. The

Connection component 76 may in particular be connected / integrally formed with at least one adjustable blocking component of valve device 20.

In the illustrated embodiment, at least one flow-through opening 78 is formed in the piston component 30, which connects the first filling volume 12 with the second filling volume 16. In the flow-through opening 78, a hydraulic connection 80 of the brake fluid reservoir 22 to the second filling volume 16 open. Optionally, the valve device 20 has a first valve body 82, which seals a taper 84 of the flow-through opening 78 in a first blocking position, while a liquid transfer between the two filling volumes 12 and 16 via the flow-through opening 78 is ensured when the first valve body 82 is present in a first throughflow position is. In addition, the valve device 20 may have a second valve body 86 which, in a second blocking position, seals a mouth opening 88 of the hydraulic connection 80 of the brake fluid reservoir 22 to the second filling volume 16, while if the second valve body 86 is present in a second throughflow position a liquid transfer through the mouth opening 88 between the second filling volume 16 and the

Brake fluid reservoir 22 is executable.

The first valve body 82 and the second valve body 86 may be arranged to one another such that upon a relative movement of the booster body 48 with respect to the piston member 30, a common adjusting movement relative to the

Perform piston components 30 (with constant distance from each other). Preferably causes a common adjustment of the two valve body 82 and 86 relative to the piston member 30 in a Einbremsrichtung 90 of the piston member 30 oppositely directed back pressure direction 92, an adjustment of the first valve body 82 from its first flow position in the first blocking position and an adjustment of the second valve body 86 from its second blocking position into its second flow-through position. Accordingly, a common adjustment movement of the two valve bodies 82 and 86 relative to the piston member 30 in the Einbremsrichtung 90, adjusting the first valve body 82 from its first locking position to its first flow position and adjusting the second valve body 86 from its second flow position in his second blocking position caused. In this case, it is ensured that, when the amplifier body 48 moves along parallel to the piston component 30, the first valve body 82 is in its first throughflow position and the second valve body 86 is in its second blocking position. This can also be described in such a way that, when the minimum distance a between the piston component 30 and the booster body 48 is maintained, the valve device 20 is in the first valve state due to the first flow-through position of the first valve body 82 and the second blocking position of the second valve body 86. Since the Mitverstellbarkeit of the booster body 48 in the minimum distance a to the piston member 30 is usually ensured only given the operability of the brake booster 46, the preferred in this situation is the presence of the valve device 20 in the first

Valve condition reliably realized.

In contrast, the distance a at a driver braking force Fb is not equal to zero and at a functional impairment of the brake booster 46 usually increases. This causes the above-described adjusting movement of the two valve bodies 82 and 86 relative to the piston member 30 in the counter-pressure direction 92 due to their connection to the booster body 48 via the connecting component 76. Thus, the first valve body 82 due to the functional impairment of

Brake booster 46 displaced from its first flow position to its first blocking position, while the second valve body 86 is adjusted in an analogous manner from its second blocking position to its second flow position. This brings about the above-described advantageous reduction of the Einbremsvolumens the first pressure chamber of the master cylinder 10 to the first filling volume 12, and the separation / shutdown of the second filling volume 16th

Although the present invention in the upper paragraphs with reference to

Master cylinder 10 is described, the piston member 30 (primary piston) acts on two independent volumes / filling volumes 12 and 16, the present invention is not limited to such a configuration of the master cylinder 10. Instead, the invention also includes differently designed master cylinder 10, the volumes of which can be combined by means of the valve device 20 or act separately on a brake circuit. If the valve device 20 is designed as an additional valve, standard master cylinder 10 can also be used to implement the present invention be used. An implementation of the invention by switching a

mechanical valve or multiple mechanical valves is also possible.

FIG. 6 is a flowchart illustrating an embodiment of the method of operating a master cylinder. FIG.

The method described below can be carried out, for example, by means of one of the embodiments already described above. The feasibility of here

However, the method described is not limited to the use of the embodiments.

In a method step S1, a size of a pressure chamber of a

Master cylinder on at least one liquid-fillable first filling volume of the master cylinder whose first size is variable by adjusting at least a first piston wall, and on a liquid-fillable second filling volume of the master cylinder whose second size is variable by adjusting at least one second piston wall fixed. This is done by releasing a first hydraulic connection between the first filling volume and the second filling volume and prohibiting a second hydraulic connection between the second filling volume and a brake fluid reservoir. The method step S1 can be done by a one-piece valve device or by a

Valve device are made of a plurality of separately formed valve units. In a further method step S2, the size of the pressure chamber is fixed at least to the first filling volume which can be filled with the liquid, while at the same time the second internal pressure present in the second filling volume is set to the reservoir pressure (atmospheric pressure). This is done by prohibiting the first hydraulic connection between the first filling volume and the second

Filling volume and unlock the second hydraulic connection between the second filling volume and the brake fluid reservoir.

The method described above is not limited to an execution of method steps S1 and S2 in the order given. Instead, the method step can also be carried out before method step S1. Likewise, the

Process steps S1 and S2 are repeated as often as desired. By carrying out the method, the advantages already described above can be achieved. A new description of these advantages is omitted here.

Claims

claims

1 . A brake master cylinder (10) for a vehicle brake system comprising: a first fill volume (12) fillable with liquid, the first size of which is variable by adjusting at least a first piston wall (14); a second filling volume (16) which can be filled with liquid and whose second size can be varied by adjusting at least one second piston wall (18); and a valve means (20, 20a, 20b); characterized in that the first filling volume (12) via the valve means (20, 20a, 20b) is connected to the second filling volume (16) such that upon control of the valve means (20, 20a, 20b) in a first valve state a common first pressure chamber pressure in the first filling volume (12) and in the second filling volume (16) is present.

2. master cylinder (10) according to claim 1, wherein the second

Filling volume (16) via the valve device (20, 20a, 20b) is connectable to a brake fluid reservoir (22) that when controlling the valve means (20, 20a, 20b) in a second valve state in the brake fluid reservoir (22) present reservoir pressure in the second filling volume (16), while in the first filling volume (12) a deviating from the reservoir pressure first internal pressure is einsteuerbar.

3. master cylinder (10) according to claim 1 or 2, wherein the

Master cylinder (10) has a first pressure chamber, which in the control of the valve means (20, 20a, 20b) in the first Valve state at least the first filling volume (12) and the second filling volume (16) and in the control of the valve device (20, 20a, 20b) in the second valve state at least the first

Filling volume (12), wherein in the first filling volume (12) of the deviating from the reservoir pressure first internal pressure is einsteuerbar.

Master brake cylinder (10) according to one of the preceding claims, wherein the master brake cylinder (10) has a second pressure chamber (24) into which a floating piston component (26) at least partially adjustable so that in the second pressure chamber (24) present second pressure chamber pressure variable is.

Master brake cylinder (10) according to one of the preceding claims, wherein the valve device (20, 20a, 20b) is controllable via an energizing in the first valve state and a canceling of the

Bestromens in the second valve state is controllable.

A braking device for a braking system of a vehicle, comprising: a master cylinder (10) according to any one of the preceding claims; and a brake booster device (46); and / or a brake fluid reservoir (22).

Braking device according to claim 6, wherein the valve means (20, 20a, 20b) is controllable via a Bestromen in the first valve state and a cancellation of energization in the second valve state, and wherein the energizing of the valve means (20, 20a, 20b) and a

Actuator (44) of the brake booster device (46), via which a brake assist force (Fu) can be provided, via a common circuit.

Braking device according to claim 6, wherein the valve means (20, 20a, 20b) on an amplifier body (48) of the Brake booster device (46), which by means of the

Actuator device (44) of the brake booster device (46)

is provided, it is arranged that the valve device (20, 20a, 20b) by means of the booster body (46) at least from the first valve state to the second

Valve status is mechanically switchable.

9. Brake device according to claim 8, wherein means of at least one

Druckausübkomponente (74) of the booster body (48) of the

Brake force amplifier device (46) is a mechanical force on at least one switching mechanism of the valve device (20a, 20b) exercisable so that the at least one switching mechanism of the valve device (20a, 20b) is mechanically switchable.

10. Brake device according to claim 8, wherein the valve device (20, 20a, 20b) has a piston component (30) of the master cylinder (10) mitverstellbar formed housing component and at least one adjustable locking component (82, 86) of the valve device (20, 20a, 20b) via a connection component (76) with the amplifier body (48) of the

Brake booster device (46) is connected.

1 1. Braking system for a vehicle having at least one brake circuit (34, 40); and a master cylinder (10) according to any one of claims 1 to 5; or a brake device according to one of claims 6 to 8.

12. A method for operating a master cylinder (10) with the

steps:

Determining a size of a pressure chamber of the master cylinder (IO) on at least one liquid-fillable first filling volume (12) of the master cylinder (10) whose first size is varied by adjusting at least one first piston wall (14), and a with Liquid fillable second filling volume (16) of the

Master cylinder (10) whose second size is varied by adjusting at least one second piston wall (18) by releasing a first hydraulic connection between the first

Filling volume (12) and the second filling volume (16) and prohibiting a second hydraulic connection between the second

Filling volume (16) and a brake fluid reservoir (22); and

Defining the size of the pressure chamber to at least the first filling volume (12) which can be filled with liquid by blocking the first hydraulic connection between the first filling volume (12) and the second filling volume (16) and releasing the second

hydraulic connection between the second filling volume (16) and the brake fluid reservoir (22).