DE102011004041A1 - Brake system and method for operating a braking system for a vehicle - Google Patents

Abstract

The invention relates to a braking system for a vehicle having a combination of a lever device (60), via which the master brake cylinder (54) is connected to the brake pedal (50), 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 receiving signal (66a) provided by a sensor can be received with respect to an actuating force of the operation of the brake pedal (50) and / or a pressure in the master cylinder and / or in a brake circuit and with at least one predetermined comparison signal is comparable, and, a target size with respect to a in at least one wheel brake cylinder (64a, 64b) to be amplified brake fluid pressure can be fixed, and the at least one hydraulic unit (68a, 68b) is controlled such that the brake fluid pressure in the at least one wheel brake cylinder (64a , 64b) is variable, wobe i the lever means (60) is designed for a non-linear pedal ratio. Furthermore, the invention relates to a method for operating a brake system for a vehicle.

Description

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

In the DE 601 33 413 T2 a brake system with a vacuum brake booster and a hydraulic brake booster for an additional hydraulic assist power is described.

1 shows a coordinate system for explaining a conventional brake system with a vacuum brake booster and a hydraulic brake booster.

At the in 1 the coordinate system shown, the abscissa shows a driver braking force F, which exerts a driver of the equipped with the conventional braking system vehicle on a brake pedal. The ordinate of the coordinate system represents 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 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 the master cylinder is moved into. 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 brake cylinder such that the brake pressure p in the at least one wheel brake cylinder is increased in the case of the increased internal pressure.

With a driver braking force F between the minimum force F0 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 F0 and the saturation force F1.

The comparatively high slope of the brake pressure p between the minimum force F0 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 slope of the brake pressure p from the saturation force F1 would be significantly reduced during operation of the conventional brake system without hydraulic brake booster (see curve 10 ).

Starting from the saturation force F1, however, the brake pressure p can be increased by means of the hydraulic brake booster by means of a brake fluid volume additionally displaced in the at least one wheel brake cylinder (see curve 12 ). Thus, by means of the hydraulic brake booster (hydraulic brake boost), starting from a saturation point 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 achieved with an attachable blocking force FB1.

2A and 2 B show a schematic representation and a coordinate system for explaining a further conventional brake system without a brake booster. Regarding the ordinate and the abscissa of the 2 B is based on description of the coordinate system of 1 directed.

The brake system includes a brake pedal 14 , which has a connecting element 16 with at least one in at least one inner chamber 18 adjustable piston 20 a master cylinder 22 connected is. The pedal ratio of the brake system is constant. This is understood to mean that the brake pressure p present in the at least one wheel brake cylinder (not shown) has a linear function (curve 24 ) is from 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 having the features of claim 1 and a method for operating a braking system for a vehicle having 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. This can also be described in such a way that a comparatively high brake pressure in the at least one wheel brake cylinder is ensured even at an actuation level of the actuation of the brake pedal under the predetermined comparison signal or at a corresponding pressure in the master brake cylinder and / or in the at least one brake circuit , 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 vacuum brake booster conventionally present on a brake system, it is no longer necessary to provide a vacuum for brake booster by an internal combustion engine of the vehicle or an additional electric vacuum pump to the vacuum brake booster, as still required in 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 with small electric vehicles with a comparatively low weight, the present invention has an advantageous effect due to the reduction of the total weight of the brake system.

The combination of the hydraulic brake boost provided by the hydraulic device with the non-linear pedal ratio lever device (non-linear brake pedal mechanism) also results in a satisfactory brake pedal operation feeling. The expended brake pedal forces are significantly reduced both at a slight actuation of the brake pedal as well as a strong brake pedal operation. 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 at a slight brake application, d. H. can be omitted at an operating strength of the operation of the brake pedal under the predetermined comparison signal, or at a corresponding pressure. 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 does not feel a recoil triggered by an operation of the hydraulic power unit with a slight operation of the brake pedal. This advantage is ensured without the need for at least one wheel brake cylinder and the hydraulic power unit to be hydraulically decoupled from the master cylinder. Only with a strong brake pedal operation, d. H. at an operating force above the at least one comparison signal, the driver may possibly feel a triggered by the operation of the hydraulic power unit 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 brake system according to the invention with an ESP functionality (Electronic Stability Program) are equipped. 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 brake system according to the invention are also ensured 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.

1 a coordinate system for explaining a conventional brake system having a vacuum brake booster and a hydraulic brake booster;

2A and 2 B a schematic representation and a coordinate system for explaining a further conventional brake system without a brake booster;

3 a schematic representation of a first embodiment of the brake system;

4 a schematic representation of a second embodiment of the brake system;

5 a schematic representation of a third embodiment of the brake system;

6 a coordinate system for explaining an operation of the embodiments described above; and

7 another coordinate systems for explaining the operation of the embodiments described above.

Embodiments of the invention

3 shows a schematic representation of a first embodiment of the brake system.

This in 3 schematically reproduced brake system has a brake pedal 50 on. The brake pedal 50 is an example of a mounting end 52 rotatably mounted 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 around 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 in such a training two at least partially in each case an inner chamber 56 adjustable piston 58 on. The two pistons 58 are connected together so that they are adjustable together. It should be noted, however, that the brake system is not geared to a master cylinder designed as a tandem master cylinder 54 is limited. Instead of a tandem master cylinder, the brake system may also have a different master cylinder type.

The the brake pedal 50 comprehensive lever device 60 over which a driver braking force, for. As a foot force on the two pistons 58 of the master cylinder 54 is transmitted, is designed as a four-bar linkage. The lever device 60 connects the brake pedal 50 so with the two pistons 58 that upon actuation of the brake pedal 50 of at least one minimum force the two pistons 58 at least partially into the respective inner chamber 56 are adjustable. In this way, there is an internal pressure in each inner chamber 56 be increased.

The brake system also includes at least one (here shown only schematically) brake circuit 62a and 62b with at least one wheel brake cylinder 64a and 64b , The at least one wheel brake cylinder 64a and 64b is so with the master cylinder 54 hydraulically connected / switchable in a hydraulic connection that a brake pressure in the at least one wheel brake cylinder 64a and 64b with an increase in the internal pressure in the master cylinder 54 can be increased.

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 is at least one of a (not sketched) sensor provided receive signal 66a with respect to an operation amount (operation) of the brake pedal 50 and / or a pressure in the master cylinder 54 and / or in the at least one brake circuit 62a and 62b receivable.

For example, the at least one received signal 66a an information / actual size of one on the brake pedal 50 arranged Bremskraft-, Bremspedalweg- and / or brake pedal angle sensor with respect to the brake pedal 50 be applied driver braking force / include. In particular, the at least one received signal 66a an information / actual quantity with respect to a brake pedal travel provided by a brake pedal travel sensor, or a corresponding deflection, about which the brake pedal 50 and / or another component of the lever device 60 upon actuation of the brake pedal 50 is adjusted. It should be noted that other quantities in terms of the operating strength of sensors designed for this purpose via the received signal 66a to the controller 66 can be provided and received by this.

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

On the controller 66 At least one predetermined comparison signal / reference signal is stored, with which the received receive signal 66a is comparable. Such a comparison signal / reference signal may be, for example, a brake pedal travel (to be executed) and / or a driver braking force (to be executed) for a desired deceleration preset (eg, from a predetermined threshold of 0.5 g) upon actuation of the brake pedal 50 a brake pedal travel (to be executed) at a driver braking force (to be applied) corresponding to 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 deceleration (eg, from the predetermined threshold of 0.5 g), 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 designed to take into account the comparison of the received signal 66a establish a desired value with respect to a brake fluid pressure to be amplified in the at least one wheel brake cylinder with the at least one comparison signal / reference signal. Subsequently, the at least one hydraulic power unit 68a and 68b by means of the control device 66 by outputting at least one control signal 66b be controlled such that by means of the hydraulic power unit 68a and 68b the brake fluid pressure corresponding to the desired size in the at least one wheel brake cylinder 64a and 64b is changeable. The at least one hydraulic power unit 68a and 68b may in particular be a pump, a plunger and / or a valve. However, the brake system is not based on such a hydraulic power unit 68a and 68b limited.

The trained as a four-bar lever device 60 is designed for a non-linear pedal ratio. For this purpose, the lever device 60 an intermediate lever 70 on, which at an attachment end 72 is mounted on the chassis such that the intermediate lever 70 around the attachment end 72 is rotatable. A pedal connector 74 connects a connector contact point 75 on the brake pedal 50 with a pedal contact point 76 of the intermediate lever 70 ,

The connection of the pedal connector 74 with the brake pedal 50 (at the connector contact point 75 ) is formed as a first joint. The arrangement of the pedal connector 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 changeable. You can also rewrite this as an angle α between the pedal connector 74 and a tangent / longitudinal direction of the brake pedal 50 at the connector contact point 75 is changeable. Also the connection of the pedal connector 74 with the intermediate lever 70 (at the pedal contact point 76 ) is formed as a second joint, so that an angle β between the pedal connecting element 74 and a tangent / longitudinal direction of the intermediate lever 70 at the contact point 76 is changeable.

Between the contact point 76 and the attachment end 72 is a piston contact point 78 , on which one 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 element 80 with the intermediate lever 70 (at the piston contact point 78 ) is formed as a third joint. Also the position of the piston connecting element 80 to the intermediate lever 70 is thus changeable. Likewise, an angle γ between the piston connecting element 80 and a tangent / longitudinal direction at the piston contact point 78 of the intermediate lever 70 variable.

Due to the realized by means of the four-joint non-linear pedal ratio of the lever device 60 can be dispensed with an equipment of the brake system with a brake booster, such as a vacuum brake booster. Instead, the lever device realizes 60 the non-linear driver brake force brake pressure translation described in greater detail below. Thus, already a comparatively easy operation of the brake pedal 50 cause a comparatively high brake pressure despite the lack of a brake booster.

This in 3 Brake system shown 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 brake system.

This in 4 schematically reproduced brake system has in addition to the master cylinder 54 and in the at least one brake circuit 62a and 62b arranged hydraulic device with the control device 66 and the at least one hydraulic power unit 68a and 68b a brake pedal 100 with a cam arranged / formed thereon 102 on. The brake pedal 100 is at a mounting end 104 arranged on the chassis such that the brake pedal 100 by means of an actuation around the attachment end 104 is rotatable. The on the brake pedal 100 trained cam 102 is oriented so that its curvature surface 106 from one upon actuation of the brake pedal 100 from a user (preferably with the foot) touched actuating surface 108 is directed away. You can also rewrite this so that the cam 102 at a side facing away from the vehicle interior side of the brake pedal 100 is trained.

The cam 102 preferably has a part-circular edge, ie a circular edge, which, however, does not have to extend over 360 °. Instead of a part-circular cam 102 However, it is also the attachment of a teilelliptischen cam 102 on the brake pedal 100 possible. The curvature surface 106 preferably has a teilzylindermackelförmige form.

Also in this embodiment is the brake pedal 100 as part of a lever device 110 for a non-linear pedal transmission with the pistons 58 connected. The lever device 110 has a contact lever 112 on, which at an attachment end 114 is rotatably mounted on the chassis. At the contact lever 112 is a role 116 arranged, which the curvature surface 106 the cam 102 contacted. Upon actuation of the brake pedal 110 rolls the roll 116 at the vault surface 106 the cam 102 along.

Rolling along the roll 116 at the vault surface 106 the cam 102 causes a rotation of the contact lever 112 around the attachment end 114 , The role 116 is between a piston contact point 118 and the attachment end 114 of the contact lever 112 arranged. Between the piston contact point 118 and the piston 58 runs a piston-connecting element 120 , The connection of the piston connecting element 120 with the contact lever 112 (at the piston contact point 118 ) is formed as a hinge, so that an angle δ between the piston-connecting element 120 and a tangent / longitudinal direction of the contact lever 112 at the piston contact point 118 upon actuation of the brake pedal and while the roller is being rolled along 116 at the vault surface 106 is changeable. In this way is also by means of the lever device 110 the non-linear pedal ratio and its advantages, which are described in more detail below, can be ensured.

5 shows a schematic representation of a third embodiment of the braking system.

In the 5 schematically reproduced embodiment has in addition to the master cylinder 54 and in the at least one brake circuit 62a and 62b arranged hydraulic device with the control device 66 and the at least one hydraulic power unit 68a and 68b the brake pedal already described above 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 as part of a lever device 150 connected, which in addition to a curvature surface 106 the cam 102 contacting role 152 and an axially guided ram 154 includes. The axial guidance of the plunger 154 is for example by means of a guide 156 feasible, from the recess of the plunger 154 protrudes on both sides. By means of the pestle 154 is the role 152 with the pistons 58 connected.

An actuation of the brake pedal 100 causes a rolling motion of the roll 152 along the curvature surface 106 the cam 102 , However, it is a center of the role 152 only along a longitudinal direction of the axially guided plunger 154 adjustable. Perpendicular to the longitudinal direction of the plunger 154 is not a movement of the center of the role 152 possible.

Thus, also in the lever device 150 ensures a variable translation such that a non-linear pedal ratio is executed. In particular, by means of the lever device 150 Also, 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 feasible. This ensures the advantages described below also in this embodiment.

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

The abscissa of the coordinate system of 6 corresponds to a driver braking force F, which a driver of a vehicle with the embodiment of the brake system exerts on a brake pedal. The ordinates of the coordinate system of 6 indicates the braking pressure p resulting from the driver braking force F in the at least one wheel brake cylinder of the brake system.

The advantages described below apply to all the embodiments mentioned above, but are 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 F0 of the piston at least partially into an inner chamber of the Master cylinder is hineinverstellbar. 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 hydraulically connected, at least in one operating mode of the brake system, to the master brake cylinder such that the brake pressure p (F) in the at least one wheel brake cylinder can be increased when the internal pressure is increased. From a driver braking force F above the minimum force F0, 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 designed for a non-linear pedal ratio. 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. In this case, the internal pressure of the master brake cylinder, at least in the value range W, is preferably 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. The value range W is at least a portion of the applicable driver braking force F over the minimum force F0. The value range W is preferably adjacent to the minimum force F0. The minimum force F0 can in particular define a lower limit of the 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.

Exemplary embodiments of a lever device with such a non-linear pedal transmission 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 should be noted, however, that these embodiments are only examples of a realization of a lever device with such a non-linear pedal ratio, in particular for realizing the internal pressure as a steadily increasing and right-curved (concave) function of the driver braking force F within the value range W, and the following Therefore, these advantages are not limited to these.

Due to the realized by the lever device non-linear pedal ratio is also in 6 reproduced 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 increasing and right-curved (concave) curve / function of the driver brake 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 2 B registered.) The lever device for the non-linear pedal ratio, in particular the progressive driver brake force-brake pressure translation, realized in contrast to a lever device with a linear / constant pedal ratio the advantage that on an equipment of the brake system with a brake booster, such as a vacuum Brake booster and / or an electromechanical brake booster, can be dispensed with and yet a reliable vehicle deceleration is guaranteed ready 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 brake cylinder even at a low driver braking force F (between the minimum force F0 and the intermediate force FZ), a comparatively large brake pressure p (F) can be realized in the at least one wheel brake cylinder (without a brake booster). The advantageous non-linear pedal ratio thus ensures a cost-effective alternative to an equipment of the brake system with a brake booster. In addition, the space requirement and / or the total weight of the brake system can be reduced by means of a lever device for the non-linear pedal transmission.

A further advantage of the lever device for the non-linear pedal ratio is that the "brake pressure boost" realized by means of the non-linear pedal ratio is already present at a driver braking force F above but close to the minimum force F0. 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 F0 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 transmission is associated with an increased operating comfort of the preferably brake-servo-less braking system.

The means of 6 reproduced embodiment of the brake system also includes a hydraulic device with the control device and at least one hydraulic unit. 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 receive signal are already mentioned above. The received signal is compared by the control device with a predetermined comparison signal. The 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 of 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, to define a desired value with regard to a brake fluid pressure to be amplified in the at least one wheel brake cylinder. 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 not equal to zero to be amplified.

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 desired size may thus be, for example, a brake fluid volume to be transferred from the master brake cylinder, a desired pumping action 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.

In the means of the 6 reproduced brake system, 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 one by means of the curve 160 clearly reproduced increase in the brake pressure p (F) over (with the dashed curve 162 reproduced) brake pressure when not operating the hydraulic device. Thus, the brake pressure p (F) is 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) is already achievable with a lower blocking force FB3, which is significantly below the blocking force FB2 of the conventional brake system.

Thus, a satisfactory pedal feeling by means of a combination of the non-linear pedal lever and the hydraulic device can be realized. The means of 6 reproduced brake system with the advantageous combination (the lever device 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 built purely mechanical. 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 with a driver braking 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, the brake system with the advantageous combination on 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.

7 shows another coordinate systems for explaining the operation of the embodiments described above.

The abscissa of the coordinate system of 7 corresponds to a brake pedal travel s upon actuation of the brake pedal. The ordinates of the coordinate system of 7 indicates 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 Specifically, the brake pressure p (s) may be a function with a positive second derivative (left curved) 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.

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

• DE 60133413 T2 [0002]

Claims (14)

Braking system for a vehicle comprising: a master cylinder ( 54 ) with at least partially into an inner chamber ( 56 ) adjustable piston ( 58 ); a lever device ( 60 . 110 . 150 ) with a brake pedal ( 50 . 100 ) over which the piston ( 58 ) of the master cylinder ( 54 ) with the brake pedal ( 50 . 100 ) is connected such that upon actuation of the brake pedal ( 50 . 100 ) with a driver braking force (F) of at least one minimum force (F0) of the pistons ( 58 ) at least partially into the inner chamber ( 56 ) and an internal pressure in the inner chamber ( 56 ) can be increased; at least one brake circuit ( 62a . 62b ) with at least one wheel brake cylinder ( 64a . 64b ), which in such a way with the master cylinder ( 54 ) is hydraulically connected, that a brake pressure (P (F)) in the at least one wheel brake cylinder ( 64a . 64b ) is increasable with an increase in the internal pressure; and a hydraulic device with a control device ( 66 ) and at least one hydraulic power unit ( 68a . 68b ), wherein by means of the control device ( 66 ) at least one received signal provided by a sensor ( 66a ) with respect to an operating force (F) of the operation of the brake pedal ( 50 . 100 ) and / or a pressure in the master cylinder ( 54 ) and / or in the at least one brake circuit ( 62a . 62b ) and comparable with at least one predetermined comparison signal, and, a desired quantity with respect to one in the at least one wheel brake cylinder ( 64a . 64b ) to be amplified brake fluid pressure, taking into account the comparison of the at least one received signal ( 66a ) is fixable with the at least one comparison signal, and the at least one hydraulic power unit ( 68a . 68b ) is controllable such that by means of at least one hydraulic power unit ( 68a . 68b ) the brake fluid pressure in accordance with the desired size in the at least one wheel brake cylinder ( 64a . 64b ) is changeable; characterized in that the lever means ( 60 . 110 . 150 ) is designed for a non-linear pedal ratio. Brake system according to claim 1, wherein the lever device ( 60 . 110 . 150 ) is designed for the non-linear pedal ratio 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 ) is a steadily increasing and right-curved function of the driver braking force (F) at least for the driver braking force (F) in a value range (W). Braking 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. Braking system according to claim 3, wherein the lever device designed as a four-bar linkage ( 60 ) an intermediate lever ( 70 ), which around a mounting end ( 72 ) of the intermediate lever ( 70 ) is rotatably mounted, a pedal connecting element ( 74 ), which via a first joint with the brake pedal ( 50 ) and a second joint with the intermediate lever ( 70 ), and one with the piston ( 58 ) connected piston connecting element ( 80 ), which via a third joint with the intermediate lever ( 70 ). Brake system according to one of claims 1 or 2, wherein the brake pedal ( 100 ) a cam ( 102 ) whose curvature surface ( 106 ) a role ( 116 . 152 ) of the lever device ( 110 . 150 ) contacted. Braking system according to claim 5, wherein the roller ( 116 ) on a contact lever ( 112 ) of the lever device ( 110 ) which is arranged around an attachment end ( 114 ) of the contact lever ( 112 ) is rotatably arranged, and wherein one with the piston ( 58 ) connected piston connecting element ( 120 ) of the lever device ( 110 ) via a joint with the contact lever ( 112 ) connected is. Braking system according to claim 5, wherein the roller ( 152 ) on an axially guided plunger ( 154 ) of the lever device ( 150 ) is arranged. Brake system according to one of the preceding claims, wherein the at least one hydraulic power unit ( 68a . 68b ) comprises a pump, a plunger and / or a valve. Brake system according to one of the preceding claims, wherein the at least one comparison signal to be exercised brake pedal travel (s) and / or a brake force to be applied (FZ) for actuation of the brake pedal ( 50 . 100 ) corresponds to the desired deceleration preset from a predetermined threshold. Braking system according to one of the preceding claims, wherein the at least one comparison signal corresponds 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 at a delay executed by the brake system from the predetermined threshold value. Brake system according to one of the preceding claims, wherein the brake system is designed as an ESP system, as an ABS system and / or as an ASR system. Method for operating a braking system for a vehicle with a Master brake cylinder ( 54 ) with at least partially into an inner chamber ( 56 ) adjustable piston ( 58 ) and a brake pedal ( 50 . 100 ) ( 60 . 110 . 150 ) for a non-linear pedal ratio over which the piston ( 58 ) of the master cylinder ( 54 ) with the brake pedal ( 50 . 100 ) is connected in such a way that the piston ( 58 ) upon actuation of the brake pedal ( 50 . 100 ) with a driver braking force of at least one minimum force (F0) at least partially into the inner chamber ( 56 ) 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 ) at least one brake circuit ( 62a . 62b ), comprising the steps of: determining at least one actual variable (F) with respect to an actuating force (F) of the actuation of the brake pedal and / or a pressure in the master brake 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 desired size with respect to one in the at least one wheel brake cylinder ( 64a . 64b ) to be amplified brake fluid pressure, taking into account the comparison of the at least one actual size (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 ) the brake fluid pressure in accordance with the desired size in the at least one wheel brake cylinder ( 64a . 64b ) is changed. The method of claim 12, wherein as the at least one actual variable (F) applied to 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 . 110 . 150 ), the internal pressure, a brake circuit pressure in at least one brake circuit ( 62a . 62b ) and / or the brake pressure (p (F)) in the at least one wheel brake cylinder ( 64a . 64b ) be determined. Method according to claim 12 or 13, wherein the at least one actual variable (F) with a brake pedal travel to be exercised and / or a brake force (FZ) to be applied for an actuation of the brake pedal ( 50 . 100 ) to the desired deceleration specification of a predetermined threshold value, 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 ) is compared with a delay executed by the braking system from the predetermined threshold value as the at least one comparison variable.

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