BRAKING SYSTEMS FOR A VEHICLE AND METHOD FOR AUTONOMOUS BRAKING OF A VEHICLE

Description

[0001] The invention relates to braking systems for a vehicle. Furthermore, the invention relates to methods for autonomously braking a vehicle. State of the art

[0002] DE 10 2013 209 006 A1 discloses a control device for a brake-boosted autonomous braking system of a vehicle and a corresponding method for operating a brake-boosted autonomous braking system of a vehicle. By operating the control device or by executing the corresponding method, an autonomous brake pressure buildup in at least one of the hydraulic wheel brake cylinders of the respective braking system is to be effected using an active brake booster and / or at least one pump of the respective braking system.

[0003] DE 10 2012 023341 A1 discloses a wheel brake cylinder for a braking system of a vehicle, wherein the wheel brake cylinder is designed with a pressure chamber which is delimited by an adjustable first brake piston and is connected to a partial volume of a hydraulic brake circuit of the braking system in such a way that the first brake piston is adjustable by means of a pressure increased at least in the respective partial volume, an actuator and a second brake piston which is adjustable by means of operation of the actuator.

[0004] Such a wheel brake cylinder is also disclosed in US 2017 / 137008 A1.

[0005] US 2016 / 264113 A1 describes a braking system for a vehicle, which has an individual wheel brake for each wheel of the vehicle. Furthermore, at least one hydraulic wheel brake cylinder is connected to a respective subvolume of at least one hydraulic brake circuit of the braking system. Further examples of braking systems are disclosed in US 2008 / 189019 A1 and DE 10 2004 015447 A1. Disclosure of the invention

[0006] The invention provides a braking system for a vehicle having the features of claim 1, a braking system for a vehicle having the features of claim 4, a method for autonomously braking a vehicle having the features of claim 6 and a method for autonomously braking a vehicle having the features of claim 7. Advantages of the invention

[0007] The present invention provides possibilities for autonomous braking of a vehicle with (complete) functional redundancy. (Complete) functional redundancy means that the respective vehicle can still be braked autonomously without problems, even in the event of a significant functional impairment of at least one braking system component of the braking system in use, due to the guaranteed availability of a "replacement braking system component." Active intervention by a driver of the respective vehicle to bypass the at least one functionally impaired braking system component is not necessary when using the present invention. The present invention thus contributes to increasing the comfort and safety standards of fully automated (fully autonomous) driving functions.

[0008] The present invention, in particular, provides braking systems which, due to (complete) functional redundancy, advantageously meet future requirements for fully automated (fully autonomous) driving functions. In particular, any vehicle equipped with a braking system according to the invention can be braked without active driver involvement (i.e., autonomously or fully automatically), even in the event of a complete failure of its hydraulic braking system components. This can be used both for a short-term bridging function ("short-time fail operation", duration of approximately 2 minutes) and for a long-term bridging function ("long-time fail operation", duration of up to several hours). Autonomous braking of the vehicle can be understood as both autonomous slowing of the vehicle and autonomous bringing the vehicle to a standstill (or autonomously holding the vehicle at a standstill).Even a complete failure of all hydraulic brake system components of the braking system can be bridged due to the (complete) functional redundancy of the braking system without the driver having to intervene.

[0009] Even in the event of a leak in its hydraulic braking system components, each braking system according to the invention can still be used to perform fully automated (fully autonomous) driving functions. In particular, the vehicle equipped with the respective braking system can still be braked without driver intervention (i.e., autonomously / automated) despite the leak. The vehicle equipped with the respective braking system is thus ideally suited for autonomous or semi-autonomous (automated or partially automated) "driverless driving."

[0010] In an advantageous embodiment of the braking system of claim 1, the braking system comprises at least one control device, which is designed in such a way that the at least one control device can be operated at least temporarily in an autonomous braking mode, in which at least the motorized brake pressure build-up device, the at least one electromechanical and / or electromagnetic individual wheel brake and / or the respective electromechanical or electromagnetic actuator of the at least one electromechanical and / or electromagnetic wheel brake cylinder can be controlled by means of the at least one control device in such a way that the vehicle can be braked autonomously by means of the operation of the motorized brake pressure build-up device and / or by means of an operation of the at least one electromechanical and / or electromagnetic individual wheel brake and / or the at least one electromechanical and / or electromagnetic actuator.The at least one control device can thus realize (complete) functional redundancy for automated / autonomous driving (while avoiding dynamic redundancy).

[0011] As an advantageous development of the braking system of claim 2, the at least one control device present in the autonomous braking mode can be designed to brake the vehicle autonomously primarily by means of the operation of the at least one electromechanical and / or electromagnetic single-wheel brake and / or the at least one electromechanical and / or electromagnetic actuator, and to use the motorized brake pressure build-up device for autonomous braking of the vehicle only when a functional impairment of the at least one electromechanical and / or electromagnetic single-wheel brake and / or the at least one electromechanical and / or electromagnetic actuator is detected and / or when a currently maximum effective total braking power of the at least one electromechanical and / or electromagnetic single-wheel brake and the at least one electromechanical and / or electromagnetic actuator is insufficient toautonomous braking of the vehicle within a specified distance and / or within a specified time interval. The at least one electromechanical and / or electromagnetic single-wheel brake and / or the at least one electromechanical and / or electromagnetic actuator can thus be used as primary actuators (master actuators) for autonomous braking of the vehicle. Preferably, the operation of the at least one electromechanical and / or electromagnetic single-wheel brake and / or the at least one electromechanical and / or electromagnetic actuator can also be used to convert kinetic energy of the vehicle to be braked into electrical energy. The motorized brake pressure build-up device serves as a secondary actuator (slave actuator) to take over / supplement functions of the primary actuator in the event of a fault and / or in an extreme case. The motorized brake pressure build-up device (with the associatedinteracting hydraulic brake system components) thus realizes an "autonomous fallback level", which makes intervention by the vehicle to bridge functions that can no longer be carried out by means of the primary actuator unnecessary.

[0012] For example, the braking system can have a master brake cylinder connected to at least one brake circuit, in which a pressure increase can be effected by a driver of the vehicle actuating a brake actuating element connected to the master brake cylinder. In this case, the driver can still bring the vehicle to a standstill (and possibly hold it there) using his braking force, even in the event of a complete failure of all electrical components of the braking system (for example, due to a failure of the vehicle's electrical system). In addition, the motorized brake pressure build-up device can be an electromechanical brake booster located upstream of the master brake cylinder. Thus, an electromechanical brake booster that is often already installed in vehicles (such asAn electronic booster (e.g., an iBooster, an eBooster, an electronic booster, an eBKV, an electronic brake booster) can be used to implement the braking system embodiment described here. This reduces the costs incurred in implementing the embodiment.

[0013] Furthermore, the corresponding methods for autonomously braking a vehicle also provide the advantages described above. It is expressly noted that the methods for autonomously braking a vehicle can be further developed according to the embodiments of braking systems explained above. Short description of the drawings

[0014] Further features and advantages of the present invention are explained below with reference to the figures. They show: Fig. 1 shows a schematic representation of an embodiment of a braking system according to the invention; Fig. 2 shows a schematic representation of an embodiment of a further braking system according to the invention; Fig. 3 shows a flow chart for explaining a manufacturing method for an electromechanical or electromagnetic wheel brake cylinder, which does not fall under the present invention; Fig. 4 shows a flow chart for explaining an embodiment of a method according to the invention for autonomously braking a vehicle; Fig. 5 shows a flow chart for explaining an embodiment of a further method according to the invention for autonomously braking a vehicle; and Fig. 6 shows a coordinate system for explaining a further development of the Fig. 4 und Fig. 5 schematically represented procedure. Embodiments of the invention

[0015] Fig. 1 shows a schematic representation of an embodiment of a braking system according to the invention.

[0016] The Fig. 1 The schematically illustrated braking system can be mounted on a vehicle / motor vehicle, wherein only its wheels 10 of the vehicle / motor vehicle are schematically illustrated. It should be noted that the usability of the braking system type explained below is not restricted to the schematically illustrated vehicle / motor vehicle with exactly four wheels 10. Likewise, the usability of this braking system type is not limited to any specific vehicle / motor vehicle type.

[0017] The braking system comprises at least one hydraulic braking circuit 12. Although the braking system of the Fig. 1 has only a single brake circuit 12, in a further development it can also have two or more than two brake circuits 12. In addition, the braking system comprises at least one electromechanical or electromagnetic wheel brake cylinder 14, each of which is assigned to a wheel 10 of the vehicle and is connected to a respective partial volume of the at least one hydraulic brake circuit 12. As an optional addition, the at least one brake circuit 12 can also comprise at least one further braking system component, such as at least one electrically switchable valve, at least one check valve, at least one pressure relief valve, at least one storage chamber and / or at least one pressure sensor.

[0018] A pressure chamber is formed in each electromechanical or electromagnetic wheel brake cylinder 14, which is delimited by an adjustable first brake piston of the electromechanical or electromagnetic wheel brake cylinder 14. Furthermore, the respective pressure chamber of the at least one electromechanical and / or electromagnetic wheel brake cylinder 14 of the braking system can be connected to the at least one partial volume of the at least one hydraulic brake circuit 12 in such a way that the first brake piston (delimiting the respective pressure chamber) can be adjusted by means of a pressure increased at least in the respective partial volume.In particular, the respective first brake piston of the at least one electromechanical and / or electromagnetic wheel brake cylinder 14 can be pressed against a brake disc 16 of the wheel 10 assigned to it by means of the pressure increased at least in the respective partial volume such that a first braking torque (not equal to zero) counteracts a rotation of the assigned wheel 10.

[0019] The at least one electromechanical and / or electromagnetic wheel brake cylinder 14 of the braking system also has an electromechanical or electromagnetic actuator, to which a second brake piston of the respective electromechanical or electromagnetic wheel brake cylinder 14 is assigned. The respective second brake piston is adjustable by means of operation of the electromechanical or electromagnetic actuator. In particular, the respective second brake piston can be pressed against the brake disc 16 of the associated wheel 10 by means of the operation of the (associated) electromechanical or electromagnetic actuator such that a second braking torque (not equal to zero) counteracts the rotation of the associated wheel 10 as an alternative or in addition to the first braking torque.

[0020] The at least one electromechanical or electromagnetic wheel brake cylinder 14 of the braking system is thus suitable both for "hydraulic braking" of the rotation of the associated wheel 10 using the first braking torque (not equal to zero) and for "electromechanical or electromagnetic braking" of the rotation of the associated wheel 10 using the second braking torque (not equal to zero). Preferably, each electromechanical and / or electromagnetic wheel brake cylinder 14 has its own housing, in which both its first brake piston and its second brake piston are adjustably arranged. A design of the respective housing is preferred in which the electromechanical or electromagnetic actuator is also at least partially formed in the associated housing.A good interaction of the first brake piston and the second brake piston interacting therewith can also be achieved if the first brake piston and the second brake piston interacting therewith are adjustably arranged in a common brake calliper of the respective electromechanical or electromagnetic wheel brake cylinder 14.

[0021] The braking system of the Fig. 1 also has a motorized brake pressure build-up device 18, which is designed such that, by means of operation of the motorized brake pressure build-up device 18, at least one pressure present in the at least one partial volume of the at least one hydraulic brake circuit 12, to which the at least one electromechanical or electromagnetic wheel brake cylinder 14 is connected, can be increased / is increased. The motorized brake pressure build-up device 18 can thus be used for the autonomous (automated) adjustment / pressing of the at least one first brake piston of the at least one electromechanical and / or electromagnetic wheel brake cylinder 14 against the at least one associated brake disc 16.

[0022] Advantageous examples of the motorized brake pressure build-up device 18 will be discussed in more detail below.

[0023] The braking system of the Fig. 1 has at least one electromechanical and / or electromagnetic wheel brake cylinder 14 and / or one electromechanical and / or electromagnetic single-wheel brake 20 per wheel 10 of the vehicle. Each wheel 10 of the vehicle is thus assigned either its electromechanical or electromagnetic wheel brake cylinder 14 or its electromechanical and / or electromagnetic single-wheel brake 20. The at least one electromechanical and / or electromagnetic single-wheel brake 20 is to be understood as a friction brake, the brake piston of which can be pressed / is pressed against the brake disc 16 of the assigned wheel 10 by means of an electromechanical or electromagnetic actuator of the respective electromechanical or electromagnetic single-wheel brake 20 in such a way that a braking torque (not equal to zero) counteracts the rotation of the assigned wheel 10. By way of example only, in the braking system of the Fig. 1 Only one vehicle axle of the vehicle, such as a front axle of the vehicle, is assigned two electromechanical and / or electromagnetic wheel brake cylinders 14, while at least one other vehicle axle is equipped with two electromechanical and / or electromagnetic individual wheel brakes 20. However, it should be noted that in the braking system described here, exactly one electromechanical or electromagnetic wheel brake cylinder 14 can be assigned to each wheel 10 of the vehicle.

[0024] The braking system of the Fig. 1 thus comprises an "autonomous hydraulic braking system" (realized by the at least one first brake piston of the at least one electromechanical and / or electromagnetic wheel brake cylinder 14, which can be adjusted by means of the motorized brake pressure build-up device 18) and an "autonomous electromechanical and / or electromagnetic braking system" (realized by the at least one second brake piston of the at least one electromechanical and / or electromagnetic wheel brake cylinder 14, which can be adjusted by means of its actuator, and possibly by the at least one brake piston of the at least one electromechanical and / or electromagnetic single-wheel brake 20).

[0025] Both the "autonomous hydraulic braking system" and the "autonomous electromechanical and / or electromagnetic braking system" are suitable (together or individually) for the (wheel-individual) autonomous braking of the rotation of the respective assigned wheel 10 (possibly with modulation of the braking torque applied). Depending on the situation, the autonomous (automated) braking of the vehicle connected to the braking system of the Fig. 1 equipped vehicle, either only the "autonomous hydraulic braking system", only the "autonomous electromechanical and / or electromagnetic braking system", or a complete braking system consisting of the "autonomous hydraulic braking system" and the "autonomous electromechanical and / or electromagnetic braking system" can be used. The braking system is therefore advantageously suited for highly autonomous (highly automated) applications, such as an ABS function (or an ESP function), driver assistance systems for partially autonomous or fully autonomous (partially automated or fully automated) driving of the vehicle, and emergency braking functions for autonomous (automated) braking of the vehicle to a standstill (and possibly for autonomous (automated) holding of the vehicle at a standstill).

[0026] A key advantage of the braking system of the Fig. 1 There is also (complete) functional redundancy of the braking system, which allows a highly autonomous (highly automated) application to be continued or (fully) executed using the other of the two autonomous braking systems, even in the event of a complete failure of one of the two autonomous braking systems. The two autonomous braking systems thus realize (complete) functional redundancy, which still enables autonomous (automated) driving even in the event of a failure of one of the two autonomous braking systems. For example, a partially autonomous or fully autonomous (automated or partially automated) journey of the vehicle can still be continued despite the complete failure of one of the two autonomous braking systems by the vehicle continuing to drive autonomously or partially autonomously using the other of the two autonomous braking systems.The two autonomous braking systems thus realize the advantage of (complete) functional redundancy so reliably that, despite the complete failure of one of the two autonomous braking systems, support for the vehicle driver, for example by the driver applying force to at least one brake circuit 12, can be easily dispensed with. The braking system of the . Fig. 1 This creates an "autonomous fallback level," which allows highly autonomous (highly automated) applications to continue running despite the complete failure of one of the two autonomous braking systems. A reversion of the braking system to a mechanical fallback level can thus be avoided.

[0027] Just as an example, the braking system of the Fig. 1 a master brake cylinder 22 connected to the at least one brake circuit 12, in which a pressure increase can be effected by a driver of the vehicle actuating a brake actuation element (not shown) connected to the master brake cylinder 22. By increasing the pressure in the master brake cylinder 22, the at least one first brake piston of the at least one electromechanical and / or electromagnetic wheel brake cylinder 14 can also be adjusted "manually" using the driver's braking force. Thus, even in the event of an on-board power supply failure, the driver still has the option of actively braking their vehicle using their braking force. However, it should be noted that the braking system does not require a "driver interface" due to its (complete) functional redundancy. Therefore, the "driver interface" or the master brake cylinder 22 can easily be dispensed with.

[0028] Preferably, the motorized brake pressure buildup device 18 of the braking system configured with the master brake cylinder 22 is an electromechanical brake booster (such as an iBooster, an eBooster, an electronic booster, an eBKV, or an electronic brake booster) positioned upstream of the master brake cylinder 22. For the design of a motorized brake pressure buildup device 18 of a brake system without a master brake cylinder, a motorized piston-cylinder device (plunger device, Integrated Power Brake, IPB) and / or at least one pump are preferred. Thus, cost-effective and already widely used devices can be used as the motorized brake pressure buildup devices 18.

[0029] As an optional further development, the braking system of the Fig. 1 also at least one control device 24 and 26. The at least one control device 24 and 26 is each designed such that the at least one control device 24 and 26 can be operated at least temporarily in an autonomous braking mode, in which at least the motorized brake pressure build-up device 18, the at least one electromechanical and / or electromagnetic individual wheel brake 20 and / or the respective electromechanical or electromagnetic actuator of the at least one electromechanical and / or electromagnetic wheel brake cylinder 14 can be controlled by means of the at least one control device 24 and 26 such that the vehicle can be / is braked autonomously by means of the operation of the motorized brake pressure build-up device 18 and / or by means of an operation of the at least one electromechanical and / or electromagnetic individual wheel brake 20 and / or the at least one electromechanical and / or electromagnetic actuator.

[0030] The at least one control device 24 and 26 present in the autonomous braking mode can additionally be designed to brake the vehicle autonomously primarily by means of the operation of the at least one electromechanical and / or electromagnetic individual wheel brake 20 and / or the at least one electromechanical and / or electromagnetic actuator of the at least one electromechanical and / or electromagnetic wheel brake cylinder 14 (i.e., by means of the "autonomous electromechanical and / or electromagnetic braking system"). The "autonomous electromechanical and / or electromagnetic braking system" is thus used as a "master braking system" or as a "primary braking system" "in the normal case" for the (wheel-individual) autonomous braking of the rotation of the respectively assigned wheel 10 (possibly with modulation of the respectively applied braking torque). In this case, the at least one control device 24 and 26 is designed to control the motorized brake pressure build-up device 18 (orthe "autonomous hydraulic braking system") is to be used for (wheel-individual) autonomous braking of the vehicle (possibly with modulation of the braking torque applied in each case) only if a functional impairment of the at least one electromechanical and / or electromagnetic individual wheel brake 20 and / or of the at least one electromechanical and / or electromagnetic actuator of the at least one electromechanical and / or electromagnetic wheel brake cylinder 14 is detected and / or if a currently maximum effective total braking power of the at least one electromechanical and / or electromagnetic individual wheel brake 20 and of the at least one electromechanical and / or electromagnetic actuator of the at least one electromechanical and / or electromagnetic wheel brake cylinder 14 is insufficient for autonomous braking of the vehicle within a predetermined distance and / or within a predetermined time interval.The "autonomous hydraulic braking system" thus serves as a "slave braking system" or as a "secondary braking system" "in the event of a fault" to bridge the functional impairment of the "autonomous electromechanical and / or electromagnetic braking system" and / or "in extreme cases" to support the "autonomous electromechanical and / or electromagnetic braking system." Thus, a high level of redundancy is maintained even during autonomous braking (e.g., for automated or partially automated driving).

[0031] In the embodiment of the Fig. 1 The braking system comprises a first control device 24 and a second control device 26 (as the at least one control device 24 and 26). The first control device 24 serves as a "master control device" for controlling the at least one electromechanical and / or electromagnetic actuator of the at least one electromechanical and / or electromagnetic wheel brake cylinder 14 and possibly the at least one electromechanical and / or electromagnetic single-wheel brake 20 (by means of at least one first control signal 24a), while the motorized brake pressure build-up device 18 is controllable / controlled (by means of at least one second control signal 26a) by the second control device 26 used as a "slave control device". Thus, the control of the braking system of the Fig. 1 redundantly configured by means of the two control devices 24 and 26. The two control devices 24 and 26 can communicate with each other, for example, via a communication device 28. However, it should be noted that equipping the braking system with the second control device 26 is optional. Alternatively, the braking system components of the braking system can all be controlled by means of a single control device 24.

[0032] Fig. 2 shows a schematic representation of an embodiment of another braking system according to the invention.

[0033] The Fig. 2 The schematically illustrated braking system differs from the previously explained embodiment only in that the braking system comprises two braking circuits 12a and 12b, wherein at least one hydraulic wheel brake cylinder 30, which is assigned to a wheel 10 of the vehicle, is connected to a respective partial volume of the at least one hydraulic braking circuit 12a and 12b. In addition, the braking system has an electromechanical and / or electromagnetic individual wheel brake 20 for each wheel of the vehicle. Optionally, in the braking system, the Fig. 2 the number of hydraulic wheel brake cylinders 30 of the number of wheels 10 of the vehicle. Therefore, in the embodiment of the Fig. 2 a braking torque (not equal to zero) is applied to each brake disc 16 of each wheel 10 of the vehicle both by means of a brake piston of the associated hydraulic wheel brake cylinder 30 and by means of the brake piston of the associated electromechanical or electromagnetic single-wheel brake 20, a further braking torque (not equal to zero). Fig. 2 However, the brake system type shown is not limited to a specific number of brake circuits 12a and 12b or a specific number of hydraulic wheel brake cylinders 30 equal to the number of wheels 10 of the vehicle.

[0034] The braking system of the Fig. 2 comprises an "autonomous hydraulic braking system" (implemented by the at least one hydraulic wheel brake cylinder 30 cooperating with the motorized brake pressure build-up device 18) and an "autonomous electromechanical and / or electromagnetic braking system" (implemented by the brake pistons of the electromechanical and / or electromagnetic individual wheel brakes 20, which are adjustable by means of their actuators). It thus offers all the advantages of the previously explained embodiment. For example, the braking system of the Fig. 2 the "autonomous electromechanical and / or electromagnetic braking system" is used as a "master braking system" or as a "primary braking system" "under normal circumstances", while the "autonomous hydraulic braking system" is used as a "slave braking system" or as a "secondary braking system" only "in the event of a fault" to bridge a functional impairment of the "autonomous electromechanical and / or electromagnetic braking system" and / or "in extreme circumstances" to support the "autonomous electromechanical and / or electromagnetic braking system". Regarding further features of the braking system of the Fig. 2 Therefore, please refer to the above explanations.

[0035] Each of the braking systems of the Fig. 1 und 2 can be described as a symbiogenetic hydraulic-electromechanical (and / or hydraulic-electromagnetic) braking system with (complete) functional redundancy. Each of these braking systems comprises two independent autonomous braking systems (i.e., the "autonomous hydraulic braking system" and the "autonomous electromechanical and / or electromagnetic braking system"), with each of the autonomous braking systems being suitable for the autonomous execution of (wheel-specific) deceleration functions and (wheel-specific) stabilization functions. The use of the "autonomous electromechanical and / or electromagnetic braking system" as a "master braking system" or as a "primary braking system" for autonomous braking "under normal conditions" can be used to convert kinetic energy of the decelerated vehicle into electrical energy.Due to the additional usability of the "autonomous hydraulic braking system" as a "slave braking system" or as a "secondary braking system" to support the "autonomous electromechanical and / or electromagnetic braking system" "in extreme cases," it is sufficient if the at least one electromechanical and / or electromagnetic wheel brake cylinder 14 and / or the at least one electromechanical and / or electromagnetic single-wheel brake 20 are designed only for a maximum achievable total braking power below a target braking power necessary for rapid and reliable braking of the vehicle "in extreme cases." As explained in more detail below, even a relatively high target braking power (or a significantly high total friction coefficient) can be achieved by supporting the "autonomous electromechanical and / or electromagnetic braking system" using the "autonomous hydraulic braking system."

[0036] Fig. 3 shows a flow chart for explaining an embodiment of the manufacturing method for an electromechanical or electromagnetic wheel brake cylinder.

[0037] In a method step S1, a pressure chamber in the electromechanical or electromagnetic wheel brake cylinder, which is delimited by an adjustable first brake piston of the electromechanical or electromagnetic wheel brake cylinder, is formed such that the pressure chamber can be connected to a partial volume of the at least one hydraulic brake circuit of the braking system, and the first brake piston can be adjusted by means of an increased pressure in at least the partial volume. The pressure chamber and the first brake piston can, for example, be designed identically or similarly to a "pressure chamber" and an "adjustable brake piston" in a hydraulic wheel brake cylinder.

[0038] Furthermore, in a method step S2, an electromechanical or electromagnetic actuator is configured such that a second brake piston of the electromechanical or electromagnetic wheel brake cylinder is adjustable by operating the electromechanical or electromagnetic actuator. The electromechanical or electromagnetic actuator and the second brake piston can, for example, be configured identically or similarly to an "actuator" and an "adjustable brake piston" in an electromechanical and / or electromagnetic single-wheel brake. Preferably, the pressure chamber, the first brake piston, the electromechanical or electromagnetic actuator, and the second brake piston are configured in a common housing of the electromechanical or electromagnetic wheel brake cylinder.

[0039] The process steps S1 and S2 can be carried out in any order, overlapping in time and / or simultaneously.

[0040] Fig. 4 shows a flowchart for explaining an embodiment of a method according to the invention for autonomously braking a vehicle.

[0041] To carry out the method described here, for example, the braking system of the Fig. 1 However, the feasibility of the procedure is neither limited to this type of braking system nor to a specific vehicle type / motor vehicle type.

[0042] Each of the two subsequent method steps S10 and S11 is at least sometimes carried out for the autonomous braking of the vehicle: As method step S10, a motorized brake pressure build-up device of a braking system of the vehicle, which is connected to at least one hydraulic brake circuit, is operated in such a way that at least one pressure present in at least one partial volume of the at least one hydraulic brake circuit is increased, wherein at least one of the above-described electromechanical or electromagnetic wheel brake cylinders, which is each assigned to a wheel of the vehicle, is connected to the at least one partial volume of the at least one hydraulic brake circuit in such a way that the vehicle is at least partially braked autonomously by means of operation of the motorized brake pressure build-up device.

[0043] As method step S11, at least one electromechanical and / or electromagnetic single-wheel brake and / or the respective electromechanical or electromagnetic actuator of the at least one electromechanical and / or electromagnetic wheel brake cylinder per wheel of the vehicle is operated in such a way that the vehicle is braked autonomously at least partially by means of operation of the at least one electromechanical and / or electromagnetic single-wheel brake and / or the at least one electromechanical and / or electromagnetic actuator.

[0044] For autonomous braking of the vehicle / motor vehicle, only process step S10, only process step S11 or both process steps S10 and S11 can be carried out simultaneously.

[0045] Fig. 5 shows a flowchart for explaining an embodiment of a further method according to the invention for autonomously braking a vehicle.

[0046] To carry out the method described here, for example, the braking system of the Fig. 2 However, the feasibility of the procedure is neither limited to this type of braking system nor to a specific vehicle type / motor vehicle type.

[0047] Each of the two subsequent method steps S20 and S21 is at least sometimes carried out for the autonomous braking of the vehicle: As method step S20, a motorized brake pressure build-up device of a braking system of the vehicle, which is connected to at least one hydraulic brake circuit, is operated in such a way that at least one pressure present in at least one partial volume of the at least one hydraulic brake circuit is increased, wherein at least one hydraulic wheel brake cylinder, which is assigned to a wheel of the vehicle, is connected to the at least one partial volume of the at least one hydraulic brake circuit in such a way that the vehicle is at least partially braked autonomously by means of operation of the motorized brake pressure build-up device.

[0048] In addition, as method step S21, at least one electromechanical and / or electromagnetic individual wheel brake per wheel of the vehicle is operated in such a way that the vehicle is braked autonomously at least partially by means of operation of the at least one electromechanical and / or electromagnetic individual wheel brake.

[0049] For autonomous braking of the vehicle / motor vehicle, only process step S20, only process step S21 or both process steps S20 and S21 can be carried out simultaneously.

[0050] Fig. 6 shows a coordinate system to explain a further development of the Fig. 4 und Fig. 5 schematically shown procedure. In the coordinate system of the Fig. 6 an abscissa is a time axis t, while an ordinate indicates a vehicle deceleration a.

[0051] In the further training described here, the Fig. 4 und Fig. 5In the method schematically represented, the vehicle is braked autonomously primarily by means of the operation of the at least one electromechanical and / or electromagnetic individual wheel brake and / or the at least one electromechanical and / or electromagnetic actuator (i.e. by carrying out method step S11 or S21). This is indicated by the hatching A between the times t1 and t2, t3 and t4, t5 and t6, and t7 and t8. Preferably, the at least one electromechanical and / or electromagnetic individual wheel brake and / or the at least one electromechanical and / or electromagnetic actuator can additionally be used to convert kinetic energy of the vehicle to be braked into electrical energy.

[0052] However, if, as between times t3 and t4, a currently maximum effective total braking power of the at least one electromechanical and / or electromagnetic single-wheel brake and the at least one electromechanical and / or electromagnetic actuator is not sufficient for autonomous braking of the vehicle within a predetermined distance and / or within a predetermined time interval, the motorized brake pressure build-up device is also used (by additionally executing method step S10 or S20) for autonomous braking of the vehicle (hatching B). For example,If, for autonomous braking of the vehicle within the specified distance and / or within the specified time interval, a vehicle deceleration a above a maximum vehicle deceleration a threshold that can be achieved by executing method step S11 or S21 alone is necessary, at least for a short time, the motorized brake pressure buildup device can be used to bridge the "extreme case." The maximum vehicle deceleration a threshold that can be achieved by executing method step S11 or S21 alone can thus be below a vehicle deceleration a that can be achieved in the "extreme case." Cost-effective and space-saving devices can thus be used for the at least one electromechanical and / or electromagnetic single-wheel brake and / or the at least one electromechanical and / or electromagnetic actuator.

[0053] The motorized brake pressure build-up device can also be used for autonomous braking of the vehicle if a functional impairment of the at least one electromechanical and / or electromagnetic single-wheel brake and / or the at least one electromechanical and / or electromagnetic actuator is detected.

Claims

1. Brake system for a vehicle, comprising: at least one hydraulic brake circuit (12, 12a, 12b); at least one electromechanical or electromagnetic wheel brake cylinder (14) which is assigned in each case to a wheel (10) of the vehicle and is connected in each case to a respective partial volume of the at least one hydraulic brake circuit (12, 12a, 12b), comprising: - a pressure chamber which is formed in the electromechanical or electromagnetic wheel brake cylinder (14), is delimited by an adjustable first brake piston of the electromechanical or electromagnetic wheel brake cylinder (14) and is connected to the respective partial volume of the at least one hydraulic brake circuit (12, 12a, 12b) of the brake system in such a way that the first brake piston can be adjusted by means of a pressure increased at least in the respective partial volume; - an electromechanical or electromagnetic actuator; and - a second brake piston of the electromechanical or electromagnetic wheel brake cylinder (14), which can be adjusted by means of operation of the electromechanical or electromagnetic actuator; - a motorized brake pressure build-up device (18) which is formed in such a way that at least the pressure respectively present in the at least one partial volume of the at least one hydraulic brake circuit (12, 12a, 12b) can be increased by means of operation of the motorized brake pressure build-up device (18), characterized in that the brake system has a respective electromechanical and / or electromagnetic individual wheel brake (20) or the at least one electromechanical and / or electromagnetic wheel brake cylinder (14) for each wheel (10) of the vehicle, wherein the brake system comprises at least one control device (24, 26) which is formed in each case in such a way that the at least one control device (24, 26) can be operated at least temporarily in an autonomous braking mode in which at least the motorized brake pressure build-up device (18) and / or the at least one electromechanical and / or electromagnetic individual wheel brake (20) can be actuated by means of the at least one control device (24, 26) such that the vehicle can be autonomously braked by means of the operation of the motorized brake pressure build-up device (18) and / or by means of operation of the at least one electromechanical and / or electromagnetic individual wheel brake (20), wherein the at least one control device (24, 26) present in the autonomous braking mode is designed to autonomously brake the vehicle primarily by means of the operation of the at least one electromechanical and / or electromagnetic individual wheel brake (20) and to use the motorized brake pressure build-up device (18) to autonomously brake the vehicle only when a functional impairment of the at least one electromechanical and / or electromagnetic individual wheel brake (20) is established and / or when a currently maximum implementable total braking power of the at least one electromechanical and / or electromagnetic individual wheel brake (20) and the at least one electromechanical and / or electromagnetic actuator is not sufficient for autonomously braking the vehicle within a predefined distance and / or within a predefined time interval.

2. Brake system according to Claim 1, wherein the at least one control device (24, 26) is formed in such a way that the at least one control device (24, 26) can be operated at least temporarily in an autonomous braking mode in which the respective electromechanical or electromagnetic actuator of the at least one electromechanical and / or electromagnetic wheel brake cylinder (14) can be actuated by means of the at least one control device (24, 26) such that the vehicle can be autonomously braked by means of the operation of the motorized brake pressure build-up device (18) and / or by means of operation of the at least one electromechanical and / or electromagnetic individual wheel brake (20) and / or the at least one electromechanical and / or electromagnetic actuator.

3. Brake system according to Claim 2, wherein the at least one control device (24, 26) present in the autonomous braking mode is designed to autonomously brake the vehicle primarily by means of the operation of the at least one electromechanical and / or electromagnetic actuator and to use the motorized brake pressure build-up device (18) to autonomously brake the vehicle only when a functional impairment of at least one electromechanical and / or electromagnetic actuator is established.

4. Brake system for a vehicle, comprising: at least one hydraulic brake circuit (12, 12a, 12b); at least one hydraulic wheel brake cylinder (30) which is assigned in each case to a wheel (10) of the vehicle and is connected in each case to a respective partial volume of the at least one hydraulic brake circuit (12, 12a, 12b); a motorized brake pressure build-up device (18) which is formed in such a way that at least one pressure respectively present in the at least one partial volume of the at least one hydraulic brake circuit (12, 12a, 12b) can be increased by means of operation of the motorized brake pressure build-up device (18); and at least one further motorized device (20); wherein the brake system has a respective electromechanical and / or electromagnetic individual wheel brake (20) for each wheel (10) of the vehicle as the at least one further motorized device (20), and wherein the brake system comprises at least one control device (24, 26) which is formed in each case in such a way that the at least one control device (24, 26) can be operated at least temporarily in an autonomous braking mode in which at least the motorized brake pressure build-up device (18) and / or the at least one electromechanical and / or electromagnetic individual wheel brake (20) can be actuated by means of the at least one control device (24, 26) such that the vehicle can be autonomously braked by means of the operation of the motorized brake pressure build-up device (18) and / or by means of operation of the at least one electromechanical and / or electromagnetic individual wheel brake (20), characterized in that the at least one control device (24, 26) present in the autonomous braking mode is designed to autonomously brake the vehicle primarily by means of the operation of the at least one electromechanical and / or electromagnetic individual wheel brake (20), and to use the motorized brake pressure build-up device (18) to autonomously brake the vehicle only when a functional impairment of the at least one electromechanical and / or electromagnetic individual wheel brake (20) is established and / or when a currently maximum implementable total braking power of the at least one electromechanical and / or electromagnetic individual wheel brake (20) is not sufficient for autonomously braking the vehicle within a predefined distance and / or within a predefined time interval.

5. Brake system according to any of Claims 1 to 4, wherein the brake system has a master brake cylinder (22) which is connected to the at least one brake circuit (12, 12a, 12b) and in which an increase in pressure can be implemented by a driver of the vehicle by means of actuation of a brake actuating element connected to the master brake cylinder (22), and wherein the motorized brake pressure build-up device (18) is an electromechanical brake booster (18) upstream of the master brake cylinder (22).

6. Method for autonomously braking a vehicle, wherein the two following steps (S10 and S11) are executed for autonomously braking the vehicle: operating a motorized brake pressure build-up device (18), which is connected to at least one hydraulic brake circuit (12, 12a, 12b), of a brake system of the vehicle in such a way that at least one pressure respectively present in at least one partial volume of the at least one hydraulic brake circuit (12, 12a, 12b) is increased, wherein at least one electromechanical or electromagnetic wheel brake cylinder (14), which is assigned in each case to a wheel (10) of the vehicle, is connected to the at least one partial volume of the at least one hydraulic brake circuit (12, 12a, 12b) such that the vehicle is at least partially autonomously braked (S10) by means of operation of the motorized brake pressure build-up device (18), wherein the at least one electromechanical or electromagnetic wheel brake cylinder (14) is formed with: - a pressure chamber which is formed in the electromechanical or electromagnetic wheel brake cylinder (14), is delimited by an adjustable first brake piston of the electromechanical or electromagnetic wheel brake cylinder (14) and is connected to the respective partial volume of the at least one hydraulic brake circuit (12, 12a, 12b) of the brake system in such a way that the first brake piston can be adjusted by means of the pressure increased at least in the respective partial volume; - an electromechanical or electromagnetic actuator; and - a second brake piston of the electromechanical or electromagnetic wheel brake cylinder (14), which can be adjusted by means of operation of the electromechanical or electromagnetic actuator; and operating at least one electromechanical and / or electromagnetic individual wheel brake (20) and / or the respective electromechanical or electromagnetic actuator of the at least one electromechanical and / or electromagnetic wheel brake cylinder (14) for each wheel (10) of the vehicle in such a way that the vehicle is at least partially autonomously braked (S11) by means of operation of the at least one electromechanical and / or electromagnetic individual wheel brake (20) and / or the at least one electromechanical and / or electromagnetic actuator; characterized by the step that the vehicle is autonomously braked primarily by means of the operation of the at least one electromechanical and / or electromagnetic individual wheel brake (20) and / or the at least one electromechanical and / or electromagnetic actuator (14), and the motorized brake pressure build-up device (18) is used to autonomously brake the vehicle only when a functional impairment of the at least one electromechanical and / or electromagnetic individual wheel brake (20) and / or the at least one electromechanical and / or electromagnetic actuator is established and / or when a currently maximum implementable total braking power of the at least one electromechanical and / or electromagnetic individual wheel brake (20) and the at least one electromechanical and / or electromagnetic actuator is not sufficient for autonomously braking the vehicle within a predefined distance and / or within a predefined time interval.

7. Method for autonomously braking a vehicle, wherein the two following steps (S20 and S21) are executed for autonomously braking the vehicle: operating a motorized brake pressure build-up device (18), which is connected to at least one hydraulic brake circuit (12, 12a, 12b), of a brake system of the vehicle in such a way that at least one pressure respectively present in at least one partial volume of the at least one hydraulic brake circuit (12, 12a, 12b) is increased, wherein at least one hydraulic wheel brake cylinder (30), which is in each case assigned to a wheel (10) of the vehicle, is connected to the at least one partial volume of the at least one hydraulic brake circuit (12, 12a, 12b) such that the vehicle is at least partially autonomously braked (S20) by means of operation of the motorized brake pressure build-up device (18); and operating at least one electromechanical and / or electromagnetic individual wheel brake (20) for each wheel (10) of the vehicle in such a way that the vehicle is at least partially autonomously braked (S21) by means of operation of the at least one electromechanical and / or electromagnetic individual wheel brake (20), characterized by the step that the vehicle is autonomously braked primarily by means of the operation of the at least one electromechanical and / or electromagnetic individual wheel brake (20), and the motorized brake pressure build-up device (18) is used to autonomously brake the vehicle only when a functional impairment of the at least one electromechanical and / or electromagnetic individual wheel brake (20) is established and / or when a currently maximum implementable total braking power of the at least one electromechanical and / or electromagnetic individual wheel brake (20) is not sufficient for autonomously braking the vehicle within a predefined distance and / or within a predefined time interval.