WO2012110114A1

WO2012110114A1 - Braking system and method for operating a braking system for a vehicle

Info

Publication number: WO2012110114A1
Application number: PCT/EP2011/068559
Authority: WO
Inventors: Lothar Backes; Otmar Bussmann; Andreas Schlichenmaier; Dagobert Masur
Original assignee: Robert Bosch Gmbh
Priority date: 2011-02-14
Filing date: 2011-10-24
Publication date: 2012-08-23
Also published as: CN103547493A; JP6138869B2; CN106114475A; CN103547493B; JP2014504982A; DE102011004041A1; CN106114475B; EP2675667A1; JP5784149B2; JP2015214331A

Abstract

The invention relates to a braking system for a vehicle, comprising a combination of a lever device (60), via which the master cylinder (54) is connected to the brake pedal (50), and a hydraulic device with a control device (66) and at least one hydraulic assembly device (68a, 68b). At least one received signal (66a) which is provided by a sensor and which relates to a brake pedal (50) actuation intensity and/or to a pressure in the master cylinder and/or in a brake circuit can be received and compared with at least one specified comparison signal by means of the control device (66), and a reference variable relating to a brake fluid pressure to be boosted in at least one wheel brake cylinder (64a, 64b) can be determined. The at least one hydraulic assembly device (68a, 68b) can be controlled such that the brake fluid pressure in the at least one wheel brake cylinder (64a, 64b) can be adjusted, said lever device (60) being designed for a nonlinear pedal ratio. The invention further relates to a method for operating a braking system for a vehicle.

Description

Description title

Brake systems and method for operating a brake system for a vehicle

The invention relates to a braking system for a vehicle. Furthermore, the invention relates to a method for operating a brake system for a vehicle.

State of the art

DE 601 33 413 T2 describes a brake system with a vacuum brake booster and a hydraulic brake booster for an additional hydraulic auxiliary power.

Fig. 1 shows a coordinate system for explaining a conventional brake system with a vacuum brake booster and a hydraulic brake booster. In the coordinate system shown in Fig. 1, the abscissa shows a

Driver braking force F which a driver of the vehicle equipped with the conventional brake system applies to a brake pedal. The ordinate of the

Coordinate system reproduces the brake pressure p present at a certain driver braking force F in at least one wheel brake cylinder of the conventional brake system. By means of the coordinate system of FIG. 1, a relation p (F) with respect to the driver braking force F and the resulting brake pressure p in the at least one wheel brake cylinder can be represented.

In the conventional brake system, the brake pedal is connected to an adjustable piston of a master cylinder such that at a driver braking force F above a minimum force F0 the hydraulic counterforce opposed to the actuation and spring forces installed on the pedal and master cylinder are overcome and the piston of the master cylinder at least partially into an interior chamber of

Master cylinder is hineinverstellt. In this way, an internal pressure in the inner chamber of the master cylinder is steigerbar. The at least one

Wheel brake cylinder is hydraulically connected to the master cylinder such that the brake pressure p is mitigated in the at least one wheel brake cylinder at the increased internal pressure.

With a driver braking force F between the minimum force FO and a saturation force F1, the brake pressure p increases with increasing driver braking force F linearly (constant). This can also be described as an increase in the brake pressure p with a constant gradient in a braking force range between the minimum force FO and the saturation force F1.

The comparatively high slope of the brake pressure p between the minimum force FO and the saturation force F1 can be realized by means of the vacuum brake booster.

However, starting from the saturation force F1, the vacuum brake force boost that can be realized by means of the vacuum brake booster is exhausted, so that the brake pressure p would be significantly reduced from the saturation force F1 during operation of the conventional brake system without hydraulic brake booster (see curve 10).

From the saturation force F1, however, is displaced by means of the hydraulic brake booster by an addition in the at least one wheel brake cylinder

Brake fluid volume, the brake pressure p can be increased (see curve 12). Thus, by means of the hydraulic brake boost (Hydraulic Brake Boost) from one of the saturation force F1 corresponding saturation point (run-out point) an additional

Brake pressure increase can be ensured. In particular, such a blocking pressure pB, at which the vehicle wheels are blocked, can already be applied with one

Blocking force FB1 can be achieved. FIGS. 2A and 2B show a schematic diagram and a coordinate system for explaining another conventional brake system without a brake booster. With respect to the ordinate and the abscissa of Fig. 2B is on description of

Coordinate system of Fig. 1 referenced. The brake system comprises a brake pedal 14, which is connected via a connecting element 16 with at least one piston 20 of a master brake cylinder 22 which is adjustable in at least one inner chamber 18. The pedal ratio of the brake system is constant. By this is to be understood that in the at least one (not

shown) brake pressure p is a linear function (curve 24) of the driver's braking force. The slope of this function (curve 24) is (almost) constant after application of the minimum force F0, but comparatively low. Thus, a relatively high blocking force FB2, which is well above the above-mentioned blocking force FB1, must be applied for reaching the blocking pressure pB.

Disclosure of the invention

The invention provides a braking system for a vehicle with the features of

Claim 1 and a method for operating a braking system for a vehicle with the features of claim 12. Due to the lever device for a non-linear pedal ratio of the

brake system according to the invention is already at comparatively low pedal force, a high brake pressure achievable. One can also rewrite this so that even at an operating strength of the operation of the brake pedal below the predetermined

Comparative signal, or at a corresponding pressure in the master cylinder and / or in the at least one brake circuit, a comparatively high brake pressure is ensured in the at least one wheel brake cylinder. Thus, it is possible to dispense with an equipment of the brake system according to the invention with a brake booster, such as a vacuum brake booster (vacuum booster). By eliminating the conventional manner existing on a brake system vacuum brake booster, it is no longer necessary, a vacuum for

Braking power boost by an internal combustion engine of the vehicle or an additional electric vacuum pump to the vacuum brake booster

as still required by the prior art. Also on an equipment of the brake system with a not designed as a vacuum brake booster brake booster can be dispensed with. In this way, the brake system is cheaper to carry out. In addition, the brake system according to the invention has a reduced space requirement compared to the prior art.

Due to the elimination of the brake booster and the possible additional elimination of the vacuum supply and the total weight of the brake system under a conventional braking system can be realized. Likewise, by eliminating the enumerated components, a more favorable packaging is achieved.

The braking system according to the invention is particularly advantageous when used in an electric vehicle which has no internal combustion engine. Especially for small electric vehicles with a relatively low weight affects the present invention advantageously due to the reduction in the overall weight of the brake system.

The combination of the hydraulic brake booster, which can be realized by means of the hydraulic device, with the lever device for a non-linear pedal transmission (non-linear brake pedal mechanism) also leads to a satisfactory one

Brake pedal feel. The expended brake pedal forces are both at a slight actuation of the brake pedal as well as a strong

Brake pedal operation significantly reduced. This advantage can be ensured in the brake system according to the invention also by means of a simple and inexpensive electronics of the control device.

Another advantage of the brake system according to the invention is that upon activation of the hydraulic power unit with a light brake application, i. at an operating strength of the operation of the brake pedal below the predetermined

Comparison signal, or at a corresponding pressure can be dispensed with. Thus, in a slight brake pedal operation, the driver has no recoil sensation despite the hydraulic connection that may be present between the master cylinder and the hydraulic power unit. The driver thus feels at a slight

Actuation of the brake pedal no by operation of the

Hydraulic unit device triggered recoil. This advantage is ensured without the need for at least one wheel brake cylinder and the

Hydraulic unit must be hydraulically decoupled from the master cylinder. Only with a strong brake pedal actuation, i. at a

Operating force above the at least one comparison signal, the driver may be triggered by the operation of the hydraulic power unit

Feel recoil on the brake pedal. In such a situation, however, the driver does not feel this recoil as disadvantageous, as he feels it as an acknowledgment of the brake pedal's response to the vehicle's significant deceleration it requires.

Advantageously, the vehicles for inserting the invention

Brake system equipped with an ESP functionality (Electronic Stability Program). Thus, the entire functionality in the existing ESP system or in the already used space of the ESP system, can be accommodated. For the Hydraulic device thus no additional components must be attached to the vehicle.

As an alternative or as a supplement to an embodiment of an ESP system, the brake system can also be designed for the ABS functionality and / or the ASR functionality. In this way, the advantages described in the preceding paragraph can also be ensured.

The advantages described in the upper paragraphs of the invention

Braking system are also guaranteed in the corresponding method.

Advantages of the invention

Brief description of the drawings

Further features and advantages of the present invention will be explained below with reference to the figures. Show it. a coordinate system for explaining a conventional brake system having a vacuum brake booster and hydraulic brake booster;

FIGS. 2A and 2B are a schematic diagram and a coordinate system for explaining another conventional brake system without a brake booster;

Fig. 3 is a schematic representation of a first embodiment of the brake system; Fig. 4 is a schematic representation of a second

Embodiment of the braking system;

Fig. 5 is a schematic representation of a third embodiment of the brake system; 6 shows a coordinate system for explaining an operation of the embodiments described above; and

7 shows another coordinate system for explaining the

Operation of the previously described

Embodiments.

EMBODIMENTS OF THE INVENTION FIG. 3 shows a schematic representation of a first embodiment of the invention

Braking system.

The brake system shown schematically in FIG. 3 has a brake pedal 50. The brake pedal 50 is arranged by way of example at an attachment end 52 rotatably on a (not sketched) chassis of the vehicle with the brake system / stored. An actuation of the brake pedal 50 thus causes a rotational movement of the brake pedal 50 about the attachment end 52.

The brake system has a master cylinder 54, which is formed in the illustrated embodiment as a tandem master cylinder. The master cylinder 54 has at least partially in each case in such a training two

Inner chamber 56 hineinverstellbare piston 58. The two pistons 58 are connected to each other so that they are adjustable together. It will be on it

It should be noted that the brake system is not limited to an arrangement with a master cylinder 54 designed as a tandem master cylinder. Instead of a tandem master cylinder, the brake system can also have another

Have master cylinder type.

The brake pedal 50 comprehensive lever means 60, via which a

Driver braking force, e.g. a foot force is transmitted to the two pistons 58 of the master cylinder 54 is formed as a four-bar linkage. The lever device 60 connects the brake pedal 50 with the two pistons 58 such that upon actuation of the

Brake pedal 50 of at least one minimum force, the two pistons 58 are at least partially hineinverstellbar in the respective inner chamber 56. In this way, an internal pressure in each inner chamber 56 can be increased. The brake system also includes at least one brake circuit 62a and 62b (shown only schematically here) with at least one wheel brake cylinder 64a and 64b. The at least one wheel brake cylinder 64a and 64b is hydraulically connected to the master brake cylinder 54 / switchable in a hydraulic connection that a

Brake pressure in the at least one wheel brake cylinder 64a and 64b at a

Increase of the internal pressure in the master cylinder 54 is risigerbar.

In addition, the brake system additionally has a hydraulic device with at least one control device 66 and at least one hydraulic power unit 68a and 68b. By means of the control device 66, at least one receive signal 66a provided by a sensor (not shown) can be received with respect to an actuation force (the actuation) of the brake pedal 50 and / or a pressure in the master brake cylinder 54 and / or in the at least one brake circuit 62a and 62b. For example, the at least one received signal 66a may be an information / actual variable of a braking force, brake pedal travel and / or brake pedal angle sensor arranged on the brake pedal 50 with respect to the brake pedal 50

Driver braking power to be / include. In particular, the at least one

Receiving signal 66a an information / actual size with respect to one of a

Brake pedal travel sensor provided brake pedal travel, or a corresponding deflection by which / which the brake pedal 50 and / or another component of the lever device 60 is adjusted upon actuation of the brake pedal 50 include. It should be noted that other quantities with respect to the operating strength of sensors designed for this purpose can also be provided to and received by the control device 66 via the received signal 66a.

As an alternative or in addition to such an actuating strength, the internal pressure in the at least one inner chamber 56, a brake circuit pressure in one of the brake circuits 62a and 62b and / or a current brake pressure present in a wheel brake cylinder 64a and 64b can be received by the control device 66.

On the control device 66 is also at least one predetermined

Comparison signal / reference signal deposited, with which the received received signal 66a is comparable. Such a comparison signal / reference signal can

For example, a (to be executed) brake pedal travel and / or a (to be executed) driver braking force for a target deceleration specification (eg from a predetermined Threshold value of 0.5 g) upon actuation of the brake pedal 50, a brake pedal travel (to be performed) in accordance with the intermediate force described in more detail below, an internal pressure, a brake circuit pressure, and / or a wheel brake pressure at a defined target value executed by the brake system. Delay (eg from the predetermined threshold of 0.5g), and / or an internal pressure, a brake circuit pressure and / or a brake pressure at a driver brake force equal to the intermediate force. However, the specification of the comparison signal is not limited to the values listed here. Furthermore, the control device 66 is designed to take into account the comparison of the received signal 66a with the at least one

Comparison signal / reference signal set a target size with respect to a to be amplified in the at least one wheel brake cylinder brake fluid pressure.

Subsequently, the at least one hydraulic unit 68a and 68b can be controlled by the control device 66 by outputting at least one control signal 66b such that by means of the hydraulic unit 68a and 68b, the brake fluid pressure in accordance with the target size in the at least one wheel brake cylinder 64a and 64b is variable. The at least one

Hydraulic power unit 68a and 68b may be in particular a pump, a plunger and / or a valve. However, the brake system is not limited to such a hydraulic power unit 68a and 68b.

The four-joint lever device 60 is for a non-linear

Pedal translation designed. For this purpose, the lever device 60 has an intermediate lever 70, which is mounted on a mounting end 72 on the chassis such that the intermediate lever 70 is rotatable about the attachment end 72. A pedal connector 74 connects a connector contact point 75 on the brake pedal 50 to a pedal contact point 76 of the intermediate lever 70. The connection of the pedal connector 74 to the brake pedal 50 (at the connector contact point 75) is formed as a first hinge. The

Arrangement of the pedal connecting element 74 between the brake pedal 50 and the intermediate lever 70 is thus designed so that the orientation of the pedal connecting element 74 to the brake pedal 50 (and the intermediate lever 70) is variable. One can also rewrite this so that a Wnkel α between the pedal connecting element 74 and a tangent / longitudinal direction of the brake pedal 50th can be changed at the connection element contact point 75. Also, the connection of the pedal connecting member 74 with the intermediate lever 70 (at the pedal contact point 76) is formed as a second joint, so that an angle ß between the pedal connecting member 74 and a tangent / longitudinal direction of the intermediate lever 70 at the contact point 76 changeable is.

Between the contact point 76 and the attachment end 72 is a piston-contact point 78, on which a the intermediate lever 70 with the (at least one adjacent) piston 58 connecting piston-connecting element 80 is arranged. The connection of the piston connecting member 80 with the intermediate lever 70 (at the piston contact point 78) is formed as a third joint. The position of the piston connecting element 80 to the intermediate lever 70 is thus variable.

Likewise, an angle γ between the piston connecting member 80 and a

Tangent / longitudinal direction at the piston contact point 78 of the intermediate lever 70th

variable.

Due to the realized by means of the four-bar linkage non-linear pedal ratio of the lever device 60 may be on an equipment of the brake system with a

Brake booster, such as a vacuum brake booster, are dispensed with. Instead, the lever means 60 implements the non-linear driver brake force-to-brake ratio, described in greater detail below. Thus, even a comparatively easy operation of the brake pedal 50 despite the absence of a

Brake booster cause a comparatively high brake pressure. The brake system shown in Fig. 3 has only one possible embodiment of a four-bar linkage for a non-linear pedal ratio. For the realization of the desired kinematics between the brake pedal 50 and the master cylinder 54, however, other geometries of a four-bar linkage are suitable. 4 shows a schematic representation of a second embodiment of the invention

Braking system.

The brake system shown schematically in FIG. 4 has, in addition to the master brake cylinder 54 and the hydraulic device arranged in the at least one brake circuit 62a and 62b with the control device 66 and the at least one hydraulic power unit 68a and 68b, a brake pedal 100 with one arranged / formed cam 102 on. The brake pedal 100 is disposed on a mounting end 104 on the chassis such that the brake pedal 100 is rotatable about the mounting end 104 by operation. The cam plate 102 formed on the brake pedal 100 is oriented so that its bulging surface 106 is directed away from an actuating surface 108 contacted by a user (preferably with the foot) upon actuation of the brake pedal 100. One can also rewrite this so that the cam 102 at one of the vehicle interior

directed away side of the brake pedal 100 is formed. The cam 102 preferably has a part-circular edge, i. a circular edge, which, however, does not have to extend over 360 °. Instead of a part-circular cam 102 but also attaching a teilelliptischen cam 102 to the brake pedal 100 is possible. The bulge surface 106 preferably has a part-cylinder shell shape.

Also in this embodiment, the brake pedal 100 is connected as part of a lever means 1 10 for a non-linear pedal ratio with the piston 58. The

Lever device 110 has a contact lever 1 12, which on a

Mounting end 1 14 is rotatably mounted on the chassis. At the contact lever 112, a roller 1 16 is arranged, which contacts the bulging surface 106 of the cam 102. Upon actuation of the brake pedal 110, the roller 1 16 rolls along the curvature surface 106 of the cam 102 along.

Rolling along the roller 16 at the camber surface 106 of the cam 102 causes rotation of the contact lever 112 about the mounting end 114. The roller 16 is disposed between a piston contact point 18 and the mounting end 114 of the contact lever 112. A piston connecting element 120 extends between the piston contact point 1 18 and the piston 58. The connection of the piston connecting element 120 with the contact lever 112 (at the piston contact point 118) is designed as a joint, so that a wedge δ between the piston Connecting element 120 and a tangent / longitudinal direction of the contact lever 1 12 at the piston contact point 1 18 during actuation of the brake pedal and during a Entollrollens the roller 1 16 at the curvature surface 106 is variable. In this way, by means of the lever device 1 10 described below in more detail nonlinear pedal ratio and its advantages can be ensured. FIG. 5 shows a schematic representation of a third embodiment of the invention

Braking system.

The embodiment shown schematically in FIG. 5 has, in addition to the master brake cylinder 54 and the hydraulic device arranged in the at least one brake circuit 62a and 62b, with the control device 66 and the at least one hydraulic power unit 68a and 68b already described above

Brake pedal 100 with the cam 102 on. The brake pedal 100 is in the embodiment described here with the

(At least one adjacent) piston 58 of the master cylinder 54 is connected as part of a lever device 150 which additionally comprises a roller 152 contacting the cam surface 102 of the cam 102 and an axially guided ram 154. The axial guidance of the plunger 154 can be realized, for example, by means of a guide 156, from the recess of which the plunger 154 protrudes on both sides. By means of the plunger 154, the roller 152 is connected to the piston 58.

An actuation of the brake pedal 100 causes a rolling movement of the roller 152 along the bulging surface 106 of the cam 102. However, a center of the roller 152 is adjustable only along a longitudinal direction of the axially guided plunger 154.

Perpendicular to the longitudinal direction of the plunger 154, no movement of the center of the roller 152 is possible.

Thus, a variable ratio is also in the lever device 150 such

ensures that a non-linear pedal ratio is executed. In particular, by means of the lever device 150, a pedal ratio of the driver braking force in the internal pressure / brake pressure as a progressive function of the driver braking force for at least one range of values of the driver's braking force can be realized. This ensures the advantages described below also in this embodiment.

Fig. 6 shows a coordinate system for explaining an operation of the embodiments described above.

The abscissa of the coordinate system of FIG. 6 corresponds to a driver braking force F applied to a brake pedal by a driver of a vehicle having the embodiment of the brake system. The ordinates of the coordinate system of Fig. 6 are from the Driver braking force F resulting brake pressure p in the at least one wheel brake cylinder of the brake system again.

The advantages described below apply to all of the above

Embodiments are, however, not limited to these.

The brake pedal of the advantageous brake system is connected by means of a lever device with a piston of a master cylinder such that upon actuation of the brake pedal with at least a minimum force FO of the piston is at least partially hineinverstellbar in an inner chamber of the master cylinder. In this way, an internal pressure in the inner chamber can be increased.

At least one brake circuit with the at least one wheel brake cylinder is arranged on the master brake cylinder of the brake system. The at least one

Wheel brake cylinder is at least in an operating mode of the brake system so hydraulically connected to the master cylinder that the brake pressure p (F) in the at least one wheel brake cylinder in the increase of the internal pressure is steigerbar. From a driver braking force F above the minimum force FO, the brake pressure p (F) thus has a value not equal to zero in both coordinates.

The lever device of the advantageous brake system is for a non-linear

Pedal translation designed. Preferably, the lever device is designed for a pedal ratio, in which the internal pressure of the master cylinder, which is built up in the inner chamber, is a progressive function of the driver braking force F, at least in a value range W of the driver braking force F. Preferably, the

Internal pressure of the master cylinder in this case, at least in the value range W is a function of the driver braking force F with a positive first derivative and a negative second derivative. This can also be described in such a way that the function of the internal pressure as a function of the driver braking force F within the value range W is a steadily rising and a right-curved (concave) curve / function. Of the

Value range W is at least a portion of the applicable driver braking force F above the minimum force F0. The value range W is preferably adjacent to the minimum force F0. The minimum force F0 can in particular be a lower limit of the

Define value range W. Preferably, the value range W extends from the minimum force F0 to an intermediate force FZ, which can be fixed by means of the hydraulic device described in more detail below. Embodiments of a lever device with such a non-linear

Pedal translation are already described above. In particular, the internal pressure as a steadily increasing and right-curved (concave) function of the driver braking force F within the value range W can be realized in a simple manner and cost-effectively by means of these exemplary embodiments. It is noted, however, that these

Embodiments only examples of a realization of a lever device with such a non-linear pedal ratio, in particular for the realization of

Internal pressure as a steadily increasing and right-curved (concave) function of the driver braking force F within the value range W, are, and the advantages mentioned below are therefore not limited to these.

Due to the realized by the lever device non-linear pedal ratio and the reproduced in Fig. 6 brake pressure p (F) in the at least one

Wheel brake cylinder at least in a driver braking force F in the value range W, which is preferably between the minimum force F0 and an intermediate force FZ, a function of the driver brake force F with a positive first derivative and a negative second derivative. With a driver braking force F in the value range W, the brake pressure p (F) is thus a steadily rising and right-curved (concave)

Curve / function of the driver's braking force F.

The lever means for the advantageous non-linear pedal ratio thus also causes a progressive driver brake force-brake pressure transmission. Due to this progressive driver brake force-brake pressure ratio, the brake pressure p (F) of the brake system with the advantageous pedal ratio for a driver brake force F between the minimum force F0 and the intermediate force FZ also without one of a brake booster, such as a vacuum brake booster and / or a electromechanical brake booster, in addition to the master cylinder applied supporting force on a beneficial high value. (For comparison, the curve 24 of the conventional brake system without a brake booster of Fig. 2B is plotted.) The lever device for the non-linear pedal ratio, in particular the progressive driver brake force-brake pressure ratio, thus realizes the, unlike a lever device with a linear / constant pedal ratio Advantage that on an equipment of the brake system with a brake booster, such as a vacuum brake booster and / or a

electromechanical brake booster, can be dispensed with and still one Reliable vehicle deceleration is ensured with an easily applied driver braking force.

In particular, by means of such a non-linear pedal ratio between the brake pedal and the master cylinder even at a low driver braking force F (between the minimum force FO and the intermediate force FZ) a comparatively large brake pressure p (F) in the at least one wheel brake cylinder (without a

Brake booster) can be realized. The advantageous non-linear pedal transmission thus ensures a cost-effective alternative to a fitting of the

Braking system with a brake booster. In addition, by means of a

Lever device for the non-linear pedal ratio of the space requirement and / or the total weight of the brake system reduced.

Another advantage of the non-linear pedal ratio lever means is that the "brake pressure boost" realized by the non-linear pedal ratio is already at a driver brake force F above but close to the minimum force FO. This can also be described in such a way that even with a slight actuation of the brake pedal (with a driver braking force F between the minimum force FO and the intermediate force FZ), an advantageously high brake pressure p (F) is ensured in the at least one wheel brake cylinder. Thus, the driver can already achieve a delay of the vehicle by means of such a small driver braking force, which is usually sufficient for city traffic. The driver must thus exert only a comparatively small driver braking force for operating his preferably brake booster brake system when driving in city traffic. Since the driver has to brake the vehicle relatively often when driving in city traffic, the "brake pressure boost" realized by means of the non-linear pedal ratio is one

increased ease of use of the preferably brake booster brake system connected. The reproduced by means of the Fig. 6 embodiment of the brake system also comprises a hydraulic device with the control device and at least one

Hydraulic unit facility. By means of the control device, at least one received signal provided by a sensor can be received with respect to an actuating strength of the actuation of the brake pedal and / or a pressure in the master brake cylinder and / or in the at least one brake circuit. Examples of a receivable

Received signal are already mentioned above. The received signal is from the Control device compared with a predetermined comparison signal. The

A comparison signal is, for example, a brake pedal travel (pedal travel), a brake force (pedal force), an internal pressure, a brake circuit pressure, and / or a brake pressure corresponding to the intermediate force FZ. The intermediate force FZ is relatively freely definable. In particular, the intermediate force FZ may correspond to at least one deceleration / total braking torque from a threshold value of 0.5 g.

The control device is additionally designed in consideration of the

Comparison of the received signal with the at least one comparison signal, a desired size with respect to one in the at least one wheel brake cylinder to be amplified

Set brake fluid pressure. For example, in the case of a received signal under the at least one comparison signal, the control device can set a setpoint value with respect to a brake fluid pressure to be amplified equal to zero and, with a received signal above the at least one comparison signal, setpoint value with respect to a brake fluid pressure to be amplified which is not equal to zero.

The at least one hydraulic power unit can be controlled by means of the control device in such a way that the brake fluid pressure can be changed by means of the hydraulic power unit in the at least one wheel brake cylinder in accordance with the predetermined desired value. The target size can thus, for example, a from the

Brake fluid volume to be transferred to the master cylinder, a desired pumping operation of the at least one hydraulic power unit, a desired pump frequency of the at least one hydraulic power unit and / or a desired power supply signal of the at least one hydraulic power unit. However, the designability of the controller is not limited to the examples described herein. The at least one hydraulic power unit may in particular be a pump, a plunger and / or a valve.

6, the brake fluid pressure at a driver brake force F is greater than the intermediate force FZ in the at least one wheel brake cylinder amplified. Thus, the hydraulic device for a braking force F causes greater than the intermediate force FZ by means of the curve 160 clearly reproduced increase in the brake pressure p (F) against the (represented by the dashed curve 162) brake pressure when not operating the hydraulic device. Thus, the brake pressure p (F) in addition to a brake pressure of a brake system without a brake booster and without a hydraulic device (curve 24) can be increased. By means of the advantageous braking system, in particular the above-mentioned blocking pressure pB (despite the non-existing brake booster) already at a lower blocking force FB3, which significantly below the blocking force FB2 of

conventional braking system is available.

Thus, a satisfactory pedal feeling by means of a combination of the non-linear pedal lever and the hydraulic device can be realized. The reproduced by means of Fig. 6 brake system with the advantageous combination (the lever means for the non-linear pedal ratio and the hydraulic device) is designed so that the brake pressure P (F) at a driver braking force F between the minimum force F0 and the (relatively freely definable) intermediate force FZ is constructed purely mechanically. With a driver braking force F over the intermediate force FZ, the buildup of the brake pressure p (F) takes place with an additional hydraulic assistance by the hydraulic device. Since in a driver brake force F smaller than the intermediate force FZ can be dispensed with an operation of the hydraulic device, without this being connected to the driver with a deterioration of the satisfactory pedal feel, this shows

Brake system with the advantageous combination a comparatively low

Energy consumption. Due to the advantageous non-linear pedal ratio or the resulting progressive driver brake force-brake pressure transmission, it is sufficient only at a vehicle deceleration of at least 5 m / s ² to activate the at least one hydraulic power unit for amplifying the brake fluid pressure. The intermediate force FZ, or the at least one predetermined comparison value, can therefore correspond to a driver braking force F to be applied to the brake pedal for a vehicle deceleration of 5 m / s ² . The operation of the hydraulic device thus does not / hardly affect the power consumption of the vehicle.

Fig. 7 shows another coordinate system for explaining the operation of the previously described embodiments.

The abscissa of the coordinate system of Fig. 7 corresponds to a brake pedal travel s in the operation of the brake pedal. The ordinates of the coordinate system of FIG. 7 represent the resulting brake pressure p in the at least one wheel brake cylinder of the brake system. Due to the non-linear pedal ratio of the lever device, the brake pedal travel s to be exerted for a brake pressure p (s) can be extended slightly. (The dashed curve 164 represents the brake pedal travel brake pressure relation in a conventional brake system.) Specifically, the brake pressure p (s) may be a positive second derivative (left-curved) function of the brake pressure p (s).

However, due to the low applied driver braking force, a driver does not perceive a somewhat enlarged brake pedal travel as disadvantageous. Instead, the slightly enlarged brake pedal travel s gives the driver the opportunity to precisely set the vehicle deceleration that can be predetermined with a small force.

The method steps of the method are described indirectly with reference to the above descriptions. A new description is therefore omitted here.

Claims

Claims 1. A brake system for a vehicle comprising: a master cylinder (54) having a piston (58) at least partially adjustable into an interior chamber (56); a lever device (60, 110, 150) having a brake pedal (50, 100), via which the piston (58) of the master brake cylinder (54) is connected to the brake pedal (50, 100) in such a way that upon actuation of the brake pedal ( 50, 100) with a

Driver braking force (F) of at least one minimum force (FO) of the piston (58) at least partially adjustable into the inner chamber (56) and an internal pressure in the

Inner chamber (56) are steigerbar; at least one brake circuit (62a, 62b) having at least one wheel brake cylinder (64a, 64b) which is hydraulically connected to the master brake cylinder (54) such that a brake pressure (p (F)) in the at least one wheel brake cylinder (64a, 64b) at an increase in the internal pressure can be increased; and a hydraulic device having a control device (66) and at least one

Hydraulic power unit (68a, 68b), wherein by means of the control device (66) at least one sensor signal provided by a sensor (66a) with respect to an operating strength (F) of the operation of the brake pedal (50, 100) and / or a pressure in the master cylinder (54) and / or in which at least one brake circuit (62a, 62b) can be received and is comparable with at least one predetermined comparison signal, and a desired value with respect to a brake fluid pressure to be amplified in the at least one wheel brake cylinder (64a, 64b) taking into account

Comparing the at least one received signal (66a) with the at least one comparison signal is determinable, and the at least one hydraulic unit means (68a, 68b) is controllable such that by means of at least one

Hydraulic unit means (68a, 68b) of the brake fluid pressure according to the desired size in the at least one wheel brake cylinder (64a, 64b) is variable; characterized in that the lever means (60, 110, 150) is adapted for non-linear pedal translation.

2. Braking system according to claim 1, wherein the lever means (60, 110, 150) for the non-linear pedal ratio is designed such that the internal pressure in the

Inner chamber and / or the brake pressure (p (F)) in the at least one

Wheel brake cylinder (64a, 64b) at least for the driver braking force (F) in one

Value range (W) a steadily increasing and right - curved function of the

Driver braking force (F) is.

3. Brake system according to claim 1 or 2, wherein the lever device (60) with the brake pedal (50, 100) is designed as a four-bar linkage.

4. Braking system according to claim 3, wherein the trained as a four-joint

Lever means (60) an intermediate lever (70) which is arranged rotatably about a mounting end (72) of the intermediate lever (70), a pedal connecting element (74) which via a first joint with the brake pedal (50) and via a second joint with the intermediate lever (70) is connected, and connected to the piston (58) piston connecting element (80), which via a third joint with the

Intermediate lever (70) is connected includes.

5. Braking system according to one of claims 1 or 2, wherein the brake pedal (100) has a cam (102), the curvature surface (106) a roller (116, 152) of the lever device (1 10, 150) contacted.

6. A braking system according to claim 5, wherein the roller (116) on a contact lever (1 12) of the lever means (110) is arranged, which is arranged rotatably about a mounting end (114) of the contact lever (112), and wherein one with the piston (58) connected to the piston connecting element (120) of the lever device (1 10) via a joint with the contact lever (1 12) is connected.

7. A braking system according to claim 5, wherein the roller (152) on an axially guided ram (154) of the lever means (150) is arranged.

8. A braking system according to any one of the preceding claims, wherein the at least one hydraulic power unit (68a, 68b) comprises a pump, a plunger and / or a valve.

9. Braking system according to one of the preceding claims, wherein the at least one comparison signal corresponds to a brake pedal travel (s) to be applied and / or a brake force (FZ) to be applied for actuation of the brake pedal (50, 100) to the desired deceleration preset from a predetermined threshold value.

10. Brake system according to one of the preceding claims, wherein the at least one comparison signal to an internal pressure, a brake circuit pressure in the at least one brake circuit and / or a brake pressure in the at least one

Wheel brake cylinder corresponds to a delay executed by the braking system from the predetermined threshold value.

1 1. Brake system according to one of the preceding claims, wherein the brake system is designed as ESP system, as an ABS system and / or ASR system.

12. A method for operating a brake system for a vehicle with a

Master brake cylinder (54) with an at least partially in an inner chamber (56) into adjustable piston (58) and a brake pedal (50, 100) comprising

Lever means (60, 110, 150) for a non-linear pedal ratio, via which the piston (58) of the master brake cylinder (54) is connected to the brake pedal (50, 100) such that the piston (58) upon actuation of the brake pedal (50 , 100) with a driver braking force of at least a minimum force (F0) at least partially into the inner chamber (56) into adjusted and an internal pressure in the inner chamber (56) is increased so that a brake pressure (p (F)) in at least one with the

Master cylinder (54) hydraulically connected wheel brake cylinder (64a, 64b) of at least one brake circuit (62a, 62b) is increased, comprising the steps:

Determining at least one actual size (F) with respect to an actuating strength (F) of the operation of the brake pedal and / or a pressure in the master cylinder (54) and / or in the at least one brake circuit (62a, 62b); Comparing the at least one actual variable (F) with at least one predetermined comparison variable; Determining a target size with respect to a in the at least one wheel brake cylinder (64 a, 64 b) to be amplified brake fluid pressure, taking into account

Comparing the at least one actual variable (F) with the at least one comparison variable; and

Driving a hydraulic power unit (68a, 68b) of the brake system so that by means of the hydraulic power unit (68a, 68b) of the brake fluid pressure

is changed according to the desired size in the at least one wheel brake cylinder (64a, 64b).

13. The method of claim 12, wherein as the at least one actual size (F) exerted on the brake pedal driver braking force (F), a brake pedal travel (s) of the

Brake pedal (50, 100) and / or another component of the lever device (60, 1 10, 150), the internal pressure, a brake circuit pressure in at least one brake circuit (62 a, 62 b) and / or the brake pressure (p (F)) in the at least one wheel brake cylinder (64a, 64b) are determined.

14. The method of claim 12 or 13, wherein the at least one actual size (F) with a brake pedal path to be applied and / or applied braking force (FZ) for actuation of the brake pedal (50, 100) to the target delay setting of a predetermined threshold , and / or with an internal pressure, a brake circuit pressure in at least one brake circuit (62a, 62b) and / or a brake pressure (p (F)) in the at least one wheel brake cylinder (64a, 64b) at a delay executed by the brake system from the predetermined one Threshold is compared as the at least one comparison size.