Brake system for a motor vehicle and assembly for a brake system

Abstract

A brake system for a motor vehicle, comprising a first assembly (100) in which a first electrically actuable pressure source (5) and a master brake cylinder (1), which can be actuated by means of a brake pedal (12), are arranged, a second assembly (200) in which a second electrically actuable pressure source (2) and electrically actuable inlet valves (6a-6d) are arranged for each wheel brake, wherein the second electrically actuable pressure source (2) is hydraulically connected to the inlet valves (6a-6d), wherein the first assembly (100) comprises a single pressure connection (60) for transmitting brake pressure to the second assembly (200) for actuating the wheel brakes (8a-8d), wherein the first pressure source (5) and the master brake cylinder (1) are connected to the pressure connection (60) via a system pressure line (38).

Description

[0001] Description

[0002] Braking system for a motor vehicle and assembly for a braking system

[0003] The invention relates to a braking system for a motor vehicle with a brake pedal-actuated master brake cylinder, a first electrically actuated pressure source, a second electrically actuated pressure source, and an electrically actuated inlet valve for each wheel brake. The invention further relates to a structural unit for a braking system with an electrically actuated pressure source and a master brake cylinder that can be actuated by a brake pedal.

[0004] DE 10 2018 222 478 A1 discloses brake systems comprising a brake pedal-actuated master brake cylinder, two electrically controllable pressure sources, and one inlet valve for each wheel brake. The master brake cylinder and one of the electrically controllable pressure sources are arranged in a first structural unit, and the other electrically controllable pressure source and the inlet valves are arranged in a second structural unit. The first structural unit and the second structural unit are connected to each other via at least two pressure-resistant hydraulic connecting elements.

[0005] Accordingly, the first structural unit comprises two or more pressure connections via which a brake pressure for actuating the wheel brakes is transmitted from the first structural unit to the second structural unit.

[0006] It is an object of the present invention to provide an improved braking system and an improved assembly for a braking system for hydraulically actuated wheel brakes that can be manufactured cost-effectively. Furthermore, the braking system should offer the high availability required for highly automated driving.

[0007] A further object of the invention is to minimize the number of hydraulic connections of the braking system, particularly between the components, as well as the number of hydraulic connections or connections of a component of the braking system. This object is achieved according to the invention by a braking system according to claim 1 and a component according to claim 14.

[0008] The invention is based on the idea that the braking system comprises a first structural unit in which a first electrically actuated pressure source and a master brake cylinder which can be actuated by means of a brake pedal are arranged, and a second structural unit in which a second electrically actuated pressure source and at least one electrically actuated inlet valve per wheel brake are arranged, wherein the second electrically actuated pressure source is hydraulically connected to the inlet valves. The first structural unit comprises at most one pressure connection for transmitting brake pressure for actuating the wheel brakes to the second structural unit, wherein the first pressure source and the master brake cylinder are connected to this pressure connection via a system pressure line. This means that the first pressure source and the master brake cylinder are jointly connected to a single pressure connection of the first structural unit.

[0009] The braking system offers the advantage of enabling highly automated driving thanks to its two electrically actuated pressure sources, as well as providing a mechanical-hydraulic fallback system in the event of a total electrical failure. The braking system can be manufactured cost-effectively due to the small number of connections between the individual components and hydraulic connections.

[0010] The braking system for a motor vehicle is designed for at least two hydraulically actuated wheel brakes. Preferably, it is a braking system for at least four hydraulically actuated wheel brakes. The second structural unit then comprises at least one electrically actuated inlet valve per wheel brake, with the second electrically actuated pressure source being hydraulically connected to the at least four inlet valves.

[0011] The brake system preferably comprises a pressure fluid reservoir at atmospheric pressure. The pressure fluid reservoir is particularly preferably arranged on the first structural unit.

[0012] The brake system preferably comprises an outlet valve for each wheel brake, via which the respective wheel brake is connected to the pressure fluid reservoir.

[0013] Preferably, all intake valves are connected to the single pressure port of the first assembly. Thus, all intake valves can be actuated either by the first electrically actuated pressure source or by the master brake cylinder.

[0014] Preferably, the first pressure source and the master brake cylinder within the first structural unit are connected to the pressure connection via the system pressure line.

[0015] According to a preferred development of the brake system according to the invention, the first structural unit and the second structural unit are connected to one another by at most one pressure-resistant hydraulic connecting element, wherein the pressure-resistant hydraulic connecting element is connected to the pressure connection of the first structural unit.

[0016] Particularly preferably, all inlet valves are connected to a brake supply line which is arranged in the second structural unit, wherein the brake supply line is connected, in particular via the pressure-resistant hydraulic connecting element, to the only pressure connection of the first structural unit.

[0017] Preferably, the first structural unit is pressure-tightly connected to the second structural unit only via the pressure connection.

[0018] Preferably, the first pressure source is connected to the pressure connection in such a way that no pressure medium can flow into this connection in the event of a failure of the first pressure source.

[0019] Preferably, the first pressure source is connected to the system pressure line via an electrically actuated connection valve arranged in the first structural unit. Particularly preferably, the connection valve is designed to be closed when de-energized.

[0020] Preferably, the pressure connection is connectable to the pressure fluid reservoir. Particularly preferably, the pressure connection is connectable to the pressure fluid reservoir via the master brake cylinder.

[0021] According to a preferred development of the brake system according to the invention, the pressure port is connected to the pressure fluid reservoir when the brake pedal is not applied and the first component is de-energized. Particularly preferably, the pressure port is connected to the pressure fluid reservoir via the master brake cylinder when the brake pedal is not applied and the first component is de-energized. Thus, the pressure port, and thus the connected wheel brakes, are depressurized in such a situation.

[0022] Preferably, the master brake cylinder has at least one sniffer hole via which a pressure chamber of the master brake cylinder is connected to the pressure fluid reservoir when the brake pedal is not actuated.

[0023] The master brake cylinder or its pressure chamber is preferably connected to the system pressure line or pressure port via an electrically actuated isolating valve arranged in the first structural unit. The isolating valve is particularly preferably designed to be open when de-energized, in order to ensure the connection to the pressure fluid reservoir when the first structural unit is de-energized.

[0024] Preferably, a simulator is arranged in the first structural unit, which is hydraulically connected to the master brake cylinder. The simulator provides the driver with a brake pedal feel in a by-wire mode.

[0025] The master brake cylinder is preferably connected to the simulator via an electrically actuated simulator valve. The simulator valve is particularly preferably arranged in the first structural unit. The simulator valve is particularly preferably designed to be closed when de-energized, so that the simulator is deactivated when the first structural unit is de-energized and cannot receive any pressure fluid.

[0026] Preferably, the first structural unit additionally comprises a compensating connection for connection to the pressure fluid reservoir. Particularly preferably, the first structural unit does not comprise any additional hydraulic connection besides the pressure connection and the compensating connection.

[0027] Preferably, the sniffer hole of the master brake cylinder is connected to the compensation port.

[0028] Preferably, the first electrically actuated pressure source is connected to the compensation port, particularly preferably via a check valve opening in the direction of the first pressure source, in order to be able to draw in pressure medium. Particularly preferably, the check valve is arranged in the first structural unit.

[0029] Alternatively, it is preferred that the first structural unit, in addition to the pressure connection, comprises a first equalizing connection for connection to the pressure fluid reservoir and a second equalizing connection for connection to the pressure fluid reservoir. Particularly preferably, the electrically actuated pressure source is connected to the first equalizing connection via a check valve opening in the direction of the pressure source. Particularly preferably, the sniffer hole of the master brake cylinder is connected to the second equalizing connection.

[0030] Preferably, the first structural unit does not comprise any further electrically actuated valve in addition to the isolating valve, the connecting valve and the simulator valve.

[0031] Preferably, the first structural unit comprises no further electrically actuated valve in addition to an electrically actuated isolating valve, via which the master brake cylinder is connected to the system pressure line, an electrically actuated connecting valve, via which the first pressure source is connected to the system pressure line, and an electrically actuated simulator valve, via which the master brake cylinder is hydraulically connected to a simulator arranged in the first structural unit.

[0032] According to a preferred development of the brake system according to the invention, the second structural unit comprises a hydraulic wheel connection for each wheel brake for connection to the wheel brakes, a compensation connection for connection to the pressure medium reservoir and, in particular, only one pressure connection for connection to the first structural unit.

[0033] The second structural unit preferably comprises at least two, particularly preferably at least four, hydraulic wheel connections for connection to the wheel brakes, a compensating connection for connection to the pressure medium reservoir and, in particular, only one pressure connection for connection to the first structural unit.

[0034] Preferably, the pressure connection of the second structural unit is connected to the pressure connection of the first structural unit via a pressure-resistant hydraulic connecting element. Particularly preferably, the second structural unit does not comprise any further hydraulic connection.

[0035] Preferably, in the second structural unit, a brake supply line connects the, particularly preferably at least four, inlet valves to the pressure connection of the second structural unit and the second pressure source.

[0036] Preferably, the compensation connection of the first structural unit and the compensation connection of the second structural unit are connected to different chambers of the pressure medium reservoir.

[0037] Preferably, the second pressure source is connected to the pressure medium reservoir on the suction side, in particular without the interposition of an electrically actuated valve.

[0038] Preferably, the second pressure source is connected to the pressure medium reservoir on the suction side without the interposition of a valve.

[0039] Preferably, the second pressure source is connected to the pressure medium reservoir via the compensation connection of the second structural unit.

[0040] Preferably, the pressure connection of the first structural unit (or the system pressure line) and the second pressure source (or its pressure side) are connected to a brake supply line to which the, particularly preferably at least four, inlet valves are connected.

[0041] Preferably, the second structural unit comprises a brake supply line to which the, in particular at least four, inlet valves are connected, and which is connected to the pressure connection of the first structural unit (or the system pressure line) and the second pressure source (hydraulically).

[0042] Preferably, the brake system comprises for each wheel brake the inlet valve and an outlet valve for adjusting wheel-specific brake pressures which are derived from the brake supply pressure in the brake supply line, wherein in the non-actuated state the inlet valves forward the brake supply pressure to the wheel brakes and the outlet valves block an outflow of pressure medium from the wheel brakes.

[0043] Particularly preferably, all outlet valves are connected to the pressure medium reservoir at atmospheric pressure via a common return line. Most preferably, all outlet valves are connected to the equalization port of the second structural unit.

[0044] The pressure connection of the first unit (or the

[0045] The system pressure line is connected to the brake supply line via an electrically actuated second isolating valve. The second isolating valve is particularly preferably arranged in the second structural unit. The second isolating valve is particularly preferably designed to be open when de-energized.

[0046] According to a preferred development of the brake system according to the invention for at least two hydraulically actuated wheel brakes, an electrically actuated circuit isolating valve is arranged in the brake supply line such that, when the circuit isolating valve is closed, the brake supply line is hydraulically separated into a first line section and a second line section, wherein the first line section is hydraulically connected to the second pressure source and at least one of the at least two inlet valves and the second line section is hydraulically connected to the pressure connection of the first structural unit and the other inlet valve.

[0047] According to a preferred development of the brake system according to the invention for at least four hydraulically actuated wheel brakes, an electrically actuated circuit isolating valve is arranged in the brake supply line such that, when the circuit isolating valve is closed, the brake supply line is hydraulically separated into a first line section and a second line section, wherein the first line section is hydraulically connected to the second pressure source and at least two of the at least four inlet valves and the second line section is hydraulically connected to the pressure connection of the first structural unit and the other, in particular at least two of the at least four, inlet valves.

[0048] Preferably, the circuit isolation valve is arranged in the second structural unit.

[0049] Preferably, the circuit isolation valve is controlled by an electronic control device of the second unit. In the event of a failure of the first unit, circuit isolation can still be performed using the circuit isolation valve.

[0050] Preferably, the circuit isolation valve is designed to be open when de-energized, so that the circuit isolation valve does not have to be activated to actuate all wheel brakes by means of one of the pressure sources or the master brake cylinder.

[0051] Preferably, a first pressure sensor is arranged in the first structural unit, which determines a pressure generated by the master brake cylinder.

[0052] Preferably, a second pressure sensor is arranged in the second structural unit, which determines a pressure in the brake supply line, in particular a pressure in the second line section.

[0053] Preferably, a third pressure sensor is arranged in the second structural unit, which determines an inlet pressure of the second structural unit. Particularly preferably, the third pressure sensor is arranged hydraulically upstream of the second isolation valve, i.e., between the first structural unit and the second isolation valve.

[0054] Preferably, a second simulator and a second simulator valve are arranged in the second structural unit, wherein the second simulator is connected to the pressure connection of the first structural unit via the second simulator valve.

[0055] According to a preferred development of the brake system according to the invention, the first structural unit comprises a first electronic control device which controls the electrically actuatable components of the first structural unit, and the second structural unit comprises a second electronic control device which controls the electrically actuatable components of the second structural unit.

[0056] The brake system preferably comprises a first electrical partition and a second electrical partition, which are electrically independent of one another, wherein the first pressure source and the first electronic control device are assigned to the first electrical partition, and wherein the second pressure source, the second electronic control device and the inlet valves, and optionally the circuit isolation valve, are assigned to the second electrical partition. The circuit isolation valve is particularly preferably assigned to the second electrical partition. In the event of a failure of the first electrical partition, a circuit separation can still be carried out by means of the circuit isolation valve. Preferably, the first electronic control device or the first electrical partition is supplied with power from a first electrical energy source, and the second electronic control device orThe second electrical partition is supplied by a second electrical energy source that is independent of the first electrical energy source. The first energy source is thus part of the first electrical partition, and the second energy source is part of the second electrical partition.

[0057] According to a further development of the invention, the first structural unit and the second structural unit are connected to each other by at most one pressure-resistant hydraulic connecting element. Additional non-pressure-resistant connecting elements between the first and second structural units are possible.

[0058] The first structural unit and the second structural unit are designed such that they are connected to each other by a maximum of one pressure-resistant hydraulic connecting element. If necessary, the first structural unit and the second structural unit can be connected to each other by additional hydraulic connecting elements, but at most one, or only one, of the hydraulic connecting elements between the first and second structural units is designed to be pressure-resistant. The additional hydraulic connecting elements are then not designed to be pressure-resistant.

[0059] Preferably, the first structural unit and the second structural unit are connected to each other by a single hydraulic connecting element, which is designed to be pressure-resistant. Additional, non-pressure-resistant connecting elements to the pressure medium reservoir are possible.

[0060] Dividing the system into two components has the advantage over a single component in that both components are smaller and lighter, and therefore easier to handle. They can also be manufactured more easily on existing production lines. On the other hand, when the system is divided into two components, each hydraulic connection between these components results in considerable effort and expense. It is therefore particularly advantageous to keep the number of hydraulic connections as small as possible. It has been shown that it is advantageous to separate the various functions of hydraulic connections as clearly as possible. For example, connections through which pressure medium is sucked in can be designed with the largest possible diameter so that they have the lowest possible hydraulic resistance. For this reason, it is advantageous if such connections do not have to be pressure-resistant.Conversely, pressure-bearing connections should not have a suction function.

[0061] Preferably, the first pressure source is formed by a cylinder-piston arrangement with a hydraulic pressure chamber, the piston of which is moved forward and backward by an electromechanical actuator. An intake port of the first pressure source is preferably hydraulically connected to the pressure fluid reservoir via a check valve opening toward the pressure chamber.

[0062] The suction side of the second pressure source is preferably connected to the return line of the outlet valves to the pressure medium reservoir.

[0063] The pressure side of the second pressure source is preferably connected to the first line section of the brake supply line.

[0064] According to a further development of the invention, the second pressure source is designed with two or more circuits. Particularly preferably, the second pressure source is designed as a two-piston pump or a multi-piston pump.

[0065] Particularly preferably, the pressure sides of the two- or multi-circuit pressure source are interconnected and the suction sides of the two- or multi-circuit pressure source are interconnected.

[0066] The braking system according to the invention is particularly suitable for implementing highly automated driving functions. With regard to the structural unit for a braking system for at least two, preferably for at least four, hydraulically actuated wheel brakes, the invention is based on the idea that the structural unit comprises an electrically actuated pressure source and a master brake cylinder which can be actuated by means of a brake pedal. The structural unit comprises at most one pressure connection for transmitting braking pressure to the wheel brakes. For this purpose, the electrically actuated pressure source and the master brake cylinder are hydraulically connected to this pressure connection via a system pressure line. This means that the electrically actuated pressure source and the brake pedal-actuated master brake cylinder are jointly connected to the single pressure connection of the structural unit for transmitting braking pressure for actuating the wheel brakes.

[0067] The unit offers the advantage that it can be manufactured cost-effectively due to the small number of connections or hydraulic connections.

[0068] Preferably, a pressure medium reservoir at atmospheric pressure is arranged on the (first) structural unit in order to supply the electrically actuated pressure source and the master brake cylinder with pressure medium.

[0069] Preferably, the (first) electrically actuated pressure source is connected to the pressure connection or the system pressure line via an electrically actuated connection valve. Particularly preferably, the connection valve is designed to be closed when de-energized. Thus, in the event of a failure of the electrically actuated pressure source, no pressure medium can flow into the connection to the pressure source.

[0070] The (first) structural unit is preferably designed such that, when the brake pedal is not actuated and the structural unit is de-energized, the pressure connection is connected to a compensating connection of the structural unit (100) for connection to a pressure fluid reservoir or to a pressure fluid reservoir at atmospheric pressure. Thus, in such a situation, the pressure connection (and thus the wheel brakes connected to it) is depressurized. Particularly preferably, the pressure connection is connected to the pressure fluid reservoir via the master brake cylinder. The master brake cylinder preferably has at least one sniffer hole, via which a pressure chamber of the master brake cylinder is connected to a pressure fluid reservoir at atmospheric pressure when the brake pedal is not actuated.

[0071] Preferably, the master brake cylinder or its pressure chamber is connected to the pressure port or the system pressure line via an electrically actuated isolating valve. Particularly preferably, the isolating valve is designed to be open when de-energized. Particularly preferably, no further electrically actuated valve is arranged in the hydraulic connection between the master brake cylinder and the pressure port besides the isolating valve.

[0072] The (first) structural unit preferably comprises a simulator hydraulically connected to the master brake cylinder. Particularly preferably, the master brake cylinder is connected to the simulator via an electrically actuated simulator valve. Most preferably, the simulator valve is designed to be closed when de-energized. Most preferably, no check valve, which would allow a pressure medium flow from the simulator toward the master brake cylinder, is connected in parallel to the simulator valve.

[0073] Preferably, the (first) structural unit comprises, in addition to the pressure connection, a compensation connection for connection to the pressure medium reservoir.

[0074] Preferably, the (first) structural unit does not comprise any further hydraulic connection besides the pressure connection and the compensation connection.

[0075] Preferably, the sniffer hole of the master brake cylinder is connected to the compensation port.

[0076] Preferably, the electrically actuated pressure source is connected to the equalizing port via a check valve opening in the direction of the pressure source in order to be able to draw in pressure fluid. Alternatively, it is preferred that the (first) structural unit comprises, in addition to the pressure port, a first equalizing port for connection to the pressure fluid reservoir and a second equalizing port for connection to the pressure fluid reservoir. Particularly preferably, the electrically actuated pressure source is connected to the first equalizing port via a check valve opening in the direction of the pressure source. Particularly preferably, the sniffer hole of the master brake cylinder is connected to the second equalizing port.

[0077] Preferably, the (first) structural unit does not comprise any further electrically actuated valve in addition to the isolating valve, the connecting valve and the simulator valve.

[0078] The brake system preferably comprises a structural unit according to the invention as the first structural unit.

[0079] Further preferred embodiments of the invention emerge from the subclaims and the following description with reference to figures.

[0080] They show schematically

[0081] Fig. 1 shows an embodiment of a structural unit according to the invention for a braking system, and

[0082] Fig. 2 shows an embodiment of a braking system according to the invention.

[0083] Fig. 1 schematically shows an embodiment of a structural unit according to the invention for a braking system for a motor vehicle.

[0084] Unit 100 is designed, for example, as an electro-hydraulic brake control unit (HECU1) with a valve block HCU1 and a first electronic control device 101 (ECU1).

[0085] Assembly 100 comprises a (first) electrically actuated pressure source 5 and a master brake cylinder 1, which can be actuated by means of a brake pedal 12. For example, a pressure fluid reservoir 4 under atmospheric pressure is arranged on assembly 100.

[0086] Master brake cylinder 1 is, for example, single-circuit and has a piston 11 that defines a hydraulic pressure chamber 10. The pressure chamber 10 is connected to the pressure fluid reservoir 4 via radial bores (sniffing holes) formed in the piston 11 and a corresponding pressure equalization line 43, wherein this hydraulic connection can be shut off by a relative movement of the piston 11. The pressure chamber 10 accommodates a return spring that positions the piston 11 in an initial position when the master brake cylinder 1 is not actuated. Thus, when the brake pedal 12 is not actuated, the pressure chamber 10 of the master brake cylinder 1 is connected to the pressure fluid reservoir 4 via the sniffing holes and the pressure equalization line 43. For example, the pressure chamber 10 is connected to a hydraulic equalization connection 63 of the assembly 100, which is connected to a first chamber 401 of the pressure fluid reservoir 4.

[0087] Furthermore, assembly 100 comprises a simulator 3 (also called a brake pedal feel simulator or travel simulator) for generating a brake pedal feel for the driver, particularly in a by-wire operating mode. Simulator 3 is hydraulically coupled to the master brake cylinder 1 and essentially has, for example, a simulator chamber 301, a simulator rear chamber 302, and a simulator piston 303 separating the two chambers 301, 302. Simulator piston 303 is supported on the valve block of the assembly by an elastic element 304 (e.g., a simulator spring) arranged in the simulator rear chamber 302. The simulator chamber 301 can be connected to the pressure chamber 10 of the master brake cylinder 1, for example, by means of an electrically actuated simulator valve 28, which is advantageously designed to be closed when de-energized. Simulator valve 28 serves to switch the simulator 3 on and off.The electrically controllable pressure source 5 of the assembly 100 is designed as a hydraulic cylinder-piston arrangement (or a single-circuit electro-hydraulic actuator (linear actuator)), the piston 36 of which can be actuated by a schematically indicated electric motor 35 with the interposition of a rotation-translation gear 39, also shown schematically, in particular can be moved forwards and backwards in order to build up and release pressure in a pressure chamber 37. The piston 36 delimits the pressure chamber 37 of the pressure source 5. To control the electric motor, a rotor position sensor 44, which detects the rotor position of the electric motor 35 and is only indicated schematically, is provided.

[0088] Pressure chamber 37 is connected, regardless of the actuation state of piston 36, via a (suction) line 42 to the hydraulic equalization connection 63 of assembly 100, which is connected to the pressure fluid reservoir 4 or its first chamber 401. A check valve 53 closing in the direction of the pressure fluid reservoir 4 is arranged in line 42.

[0089] Apart from the compensation connection 63 and the pressure connection 60, the assembly 100 does not include any further hydraulic connections.

[0090] The pressure source 5 and the master brake cylinder 1 are both connected to a system pressure line 38, which is connected to a pressure connection 60 of the assembly 100. The assembly 100 comprises only one pressure connection for transmitting brake pressure to the wheel brakes or for actuating the wheel brakes, namely the pressure connection 60. The two pressure generators, master brake cylinder 1 and electrical pressure source 5, which are designed to generate brake pressure for actuating the wheel brakes, are connected to this single pressure connection 60 of the assembly 100 via the system pressure line 38.

[0091] Master brake cylinder 1 or its pressure chamber 10 is connected to the system pressure line 38, and thus to the single pressure port 60 of the assembly 100, via an electrically actuated, preferably normally open, isolating valve 23. In the hydraulic connection between master brake cylinder 1 and pressure port 60, no other electrically actuated valve is arranged besides the isolating valve 23.

[0092] As an example, master brake cylinder 1 is connected to the isolation valve 23 and the simulator valve 28 by means of a hydraulic line 48.

[0093] Pressure source 5 or its pressure chamber 37 is connected to the system pressure line 38, and thus to the only pressure connection 60 of the assembly 100, via an electrically actuated, normally closed connection valve 27. Thus, pressure source 5 is connected to the pressure connection 60 in such a way that no pressure medium can flow into this connection in the event of a failure of the pressure source 5. In the hydraulic connection between the pressure source 5 and the pressure connection 60, for example, no further electrically actuated valve is arranged besides the connection valve 27.

[0094] Fig. 2 schematically illustrates an embodiment of a braking system according to the invention for a motor vehicle. The braking system is designed to actuate four hydraulically actuated wheel brakes 8a-8d. Wheel brakes 8a, 8b are assigned to the rear axle and wheel brakes 8c, 8d to the front axle of the vehicle.

[0095] The brake system comprises a first structural unit 100, which is designed, for example, as a first electro-hydraulic brake control unit (HECU1) with a valve block HCU1 and a first electronic control device 101 (ECU1), and a second structural unit 200, which is designed, for example, as a second electro-hydraulic brake control unit (HECU12) with a valve block HCU2 and a second electronic control device 201 (ECU2).

[0096] The first structural unit 100 of Fig. 2 corresponds to the structural unit 100 of Fig. 1.

[0097] A pressure medium reservoir 4 with, for example, two chambers is arranged on the first structural unit 100, wherein a first reservoir connection is assigned to the first chamber 401 and a second reservoir connection is assigned to the second chamber 402.

[0098] The second structural unit 200 comprises a second electrically actuated pressure source 2 and at least one electrically actuated inlet valve 6a-6d per wheel brake, wherein the second electrically actuated pressure source 2 is hydraulically connected to the four inlet valves 6a-6d.

[0099] To transmit brake pressure to actuate the wheel brakes 8a-8d, the single pressure port 60 of the first structural unit 100 is hydraulically connected to a pressure port 61 of the second structural unit 200 via a hydraulic, pressure-resistant connecting element 80. Connection 80 represents the only hydraulic pressure connection, for example, the only hydraulic connection, between the first structural unit 100 and the second structural unit 200. This is a hydraulic connection for transmitting brake pressure to actuate the wheel brakes 8a-8d. Connecting element 80 must therefore be pressure-resistant.

[0100] The pressure connection 60, and thus the first pressure source 5 as well as the master brake cylinder 1, and the second pressure source 2 are connected on the pressure side to a brake supply line 13, to which the four inlet valves 6a-6d are connected. Thus, depending on the operating mode, all four wheel brakes 8a-8d can be selectively actuated by means of the first pressure source 5 and / or the second pressure source 2 and / or the master brake cylinder 1.

[0101] An electrically actuated circuit isolation valve 40 is arranged in the brake supply line 13, so that when the circuit isolation valve 40 is closed, the brake supply line 13 is separated into a first line section 13a, to which the inlet valves 6a, 6b and the wheel brakes 8a, 8b are connected, and a second line section 13b, to which the inlet valves 6c, 6d and the wheel brakes 8c, 8d are connected. The second pressure source 2 is hydraulically connected to the first line section 13a, and the pressure connection 60, and thus the first pressure source 5 and the master brake cylinder 1, is hydraulically connected to the second line section 13b. When the circuit isolation valve 40 is closed, the brake system is thus separated or divided into two hydraulic brake circuits I and II.In the first brake circuit I, pressure source 2 is connected (via the first line section 13a) only to the wheel brakes 8a and 8b, and in the second brake circuit II, pressure connection 60 or 61 is connected (via the second line section 13b) only to the wheel brakes 8c and 8d. The circuit isolation valve 40 is advantageously designed to be open when de-energized.

[0102] The braking system comprises, for example, an inlet valve 6a-6d and an outlet valve 7a-7d for each hydraulically actuated wheel brake 8a-8d. These valves are hydraulically interconnected in pairs via central connections and each connected to a hydraulic wheel connection 9a-9d of the second structural unit 200, to which the corresponding wheel brake 8a-8d is connected. A check valve 70a-70d opening toward the brake supply line 13 is connected in parallel to each of the inlet valves 6a-6d. The output connections of the outlet valves 7a-7d are connected via a common return line 14 to a hydraulic equalization connection 62, which is connected to the pressure fluid reservoir 4 or its second chamber 402. The input connections of all inlet valves 6a-6d can be supplied with a pressure by means of the brake supply line 13 (i.e. with the circuit isolation valve 40 open) which is supplied by the first pressure source 5 or, for example,in case of failure of the first pressure source 5, from the second pressure source 2, or, e.g. in case of failure of the first and the second pressure source 5, 2, from the master brake cylinder 1 (hydraulic fallback level).

[0103] The second electrically controllable pressure source 2 of the second structural unit 200 is designed, for example, as a two-piston pump whose two pressure outputs are interconnected (to the pressure side 220 of the pressure source 2) and whose two suction inlets are interconnected (to the suction side 221 of the pressure source 2). The suction side 221 is connected to the return line 14 and thus to the equalization connection 62 or the pressure fluid reservoir 4. The pressure side 220 is connected to the first line section 13a of the brake supply line 13.

[0104] The equalization connection 62, and thus the suction side 221 of the second pressure source 2, is directly connected to the pressure fluid reservoir 4 via a line or hose 90. This connection 90 carries no pressure and can therefore have a large diameter. Line 90 is connected, for example, to the second chamber 402 of the pressure fluid reservoir 4.

[0105] In addition to the pressure source 2 and the brake pressure modulation valves 6a-6d, 7a-7d, an electrically actuated, advantageously normally open, isolating valve 26 is arranged in the second structural unit 200, for example. The isolating valve 26 is hydraulically arranged between the pressure connection 61 of the second structural unit 200 and the second line section 13b of the brake supply line 13. Thus, the pressure connection 60 of the first structural unit 100 or the system pressure line 38 of the first structural unit 100 is detachably connected to the second line section 13b or the brake supply line 13 via the isolating valve 26.

[0106] The braking system includes, for example, a pressure sensor 19 in brake circuit II (line section 13b), which is thus assigned to the second pressure source 2. However, pressure sensor 19 can also be arranged in brake circuit I, or a second pressure sensor can be provided, so that each of the two brake circuits I and II can be directly monitored by means of a pressure sensor.

[0107] For example, the brake system for leakage monitoring comprises a level measuring device 50 for determining a pressure medium level in the pressure medium reservoir 4.

[0108] For example, the components 5, 53, 27, 1, 23, 3, 28 and the line sections 38, 42, 43, 48 are arranged in the first valve block HCU1 and the components 2, 6a-6d, 70a-70d, 7a-7d, 40, 26, 19 and the line sections 13a, 13b, 14 (and the line sections between the inlet and outlet valves on the one hand and the wheel connections on the other hand) are arranged in the second valve block HCU2.

[0109] Each valve block HCU1, HCU2 is assigned an electronic control device 101, 201 (ECU1, ECU2). Each electronic control device 101, 201 comprises electrical and / or electronic elements (e.g., microcontrollers, power units, valve drivers, other electronic components, etc.) for controlling the electrically actuated components of the associated valve block and, if applicable, the associated sensors. The valve block and electronic control device are advantageously designed as an electrohydraulic unit (HECII), as is known.

[0110] For the electrical connection, connection and supply of the individual electrical or electrically actuated, controllable, evaluable or similar components of the braking system, a first electrical partition A and a second electrical partition B are provided, which are electrically independent of each other.

[0111] In the figures, those electrical components which are assigned to or belong to the first electrical partition A are marked with an arrow A, while those electrical components which are assigned to or belong to the second electrical partition B are marked with an arrow B.

[0112] The electronic control device 101 is assigned to or belongs to the first electrical partition A, while the second electronic control device 201 is assigned to or belongs to the second electrical partition B. Accordingly, the electronic control device 101 and the second electronic control device 201 are electrically independent.

[0113] To supply the braking system with electrical energy, a first electrical energy source 103, e.g., an on-board electrical system, and a second electrical energy source 203, e.g., an on-board electrical system, independent of the first energy source, are provided. The first electrical energy source 103 supplies the first electrical partition A with energy, and the second electrical energy source 203 supplies the second electrical partition B.

[0114] The first electronic control device 101 controls the first pressure source 5. Accordingly, the first pressure source 5 is assigned or associated with the first electrical partition A. For example, the first pressure source 5 is supplied with energy (from the first electrical energy source 103) via the first electronic control device 101.

[0115] The second electronic control device 201 controls the second pressure source 2. Accordingly, the second pressure source 2 is assigned or associated with the second electrical partition B. For example, the second pressure source 2 is supplied with energy (from the second electrical energy source 203) via the second electronic control device 201.

[0116] For example, the first pressure source 5 can be or is controlled exclusively by the first electronic control device 101 and the second pressure source 2 can be or is controlled exclusively by the second electronic control device 201.

[0117] The remaining components of the braking system are advantageously assigned either to the first electronic control device 101 (partition A) or to the second electronic control device 201 (partition B). This means that they are controlled or actuated by this control device and / or supplied with electrical energy and / or are connected to this control device on the signal side and / or are evaluated by this control device. To avoid further redundancies, a component can advantageously be controlled or actuated or supplied with electrical energy or connected or evaluated on the signal side only or exclusively by one of the two electronic control devices 101, 201, but not by the other electronic control device.

[0118] The first electronic control device 101 controls the electrically actuated components of the first assembly 100 and the second electronic control device 201 controls the electrically actuated components of the second assembly 200.

[0119] Accordingly, the intake and exhaust valves 6a-6d, 7a-7d are assigned to the second electrical partition B and are controlled by the second electronic control device 201. Likewise, the circuit isolation valve 40 is assigned to the second electrical partition B and is controlled by the second electronic control device 201.

[0120] The separating valve 26 for the hydraulic separation of the first structural unit 100 (pressure connection 60) and the brake supply line 13 is also assigned to the second electrical partition B and is controlled by the second electronic control device 201.

[0121] Pressure sensor 19 is also assigned to the second electrical partition B. Its signals are fed to the second electronic control device 201, where they are evaluated and processed.

[0122] The connection valve 27, the isolation valve 23 and the simulator valve 28, however, are assigned to the first electrical partition A and are controlled by the first electronic control device 101.

[0123] Furthermore, the signals of the level measuring device 50 are fed to the first electronic control device 101 and evaluated and processed by it.

[0124] The braking system preferably comprises electrically actuated parking brakes on the rear wheels. These are advantageously controlled and actuated by the first electronic control device 101 (denoted by A on the wheel brakes 8a, 8b in Fig. 1).

[0125] The exemplary braking system with a first structural unit 100 enables highly automated driving by containing two electrically controllable pressure sources 5, 2, and also provides a mechanical-hydraulic fallback level (via master brake cylinder 1) in the event of a total electrical failure. The first structural unit 100 advantageously comprises the primary of the two electrically controllable pressure sources (5), a master brake cylinder 1, which the driver can actuate via the brake pedal 12, and a pedal feel simulator 3.

[0126] The exemplary second assembly 200 can also be used in combination with a first assembly with a single pressure connection, which does not include a master brake cylinder with a simulator. This is an advantage of the invention.

[0127] However, other second structural units can also be combined with the exemplary first structural unit 100 of Fig. 1.

[0128] The first assembly 100 comprises only a single pressure port 60. This pressure port 60 can be connected to the atmosphere at the same time, and it is always connected to the atmosphere when the first assembly 100 has failed electrically and the brake pedal 12 is not actuated.

[0129] For this purpose, the master brake cylinder 1 is preferably provided with a sniffer hole and connected to the pressure port 60 via an electrically operated isolating valve 23, particularly preferably open when de-energized. Furthermore, the master brake cylinder 1 is connected to the pedal feel simulator 3 via an electrically operated simulator valve 28, particularly preferably closed when de-energized. The primary pressure source 5 is connected to the pressure port 60, preferably in such a way that no pressure medium flows into this connection after the failure of the primary pressure source 5. An electrically operated connection valve 27, particularly preferably closed when de-energized, is preferably arranged in this connection.

[0130] In normal operation, when the brake pedal 12 is actuated or when an autopilot requests braking, the isolation valve 23 is closed, the simulator valve 28 is opened, and the activation valve 27 is opened. The pedal feel is generated by the pedal feel simulator 3. The pressure buildup for actuating the wheel brakes 8a-8d occurs individually or jointly through the two pressure sources 5 and 2.

[0131] Any wheel-specific pressure modulation is carried out by the second unit 200.

[0132] If the second assembly 200 fails, the first assembly 100 builds up the wheel brake pressure in the same way and can centrally modulate the wheel brake pressure for all wheel brakes 8a-8d together.

[0133] After failure of the first unit 100, braking is carried out differently by the autopilot and by the driver:

[0134] If the first unit 100 fails and the autopilot transmits a braking request, the second unit 200 takes over the build-up and modulation of the wheel brake pressure, as would be the case in a braking system without a mechanical-hydraulic fallback level.

[0135] Now consider the case where the first assembly 100 fails and the pedal 12 is actuated. After the failure of the first assembly 100, the master brake cylinder 1 is connected to the pressure port 60 of the first assembly 100 via the normally open isolating valve 23. When the pedal is actuated, the second assembly 200 can remain passive and transmit the pressure generated by the driver to the wheel brakes 8a-8d. Depending on the design of the second assembly 200, however, the driver can also be assisted by the second pressure source 2.

[0136] In the exemplary brake system of Fig. 2, the electrically operated circuit dividing valve 40 is closed as soon as the pressure sensor 19 detects a pressure generated by the master brake cylinder 1, and the second pressure source 2 can increase the pressure in the associated wheel brakes above the master brake cylinder pressure.

[0137] To enable even greater functionality in the event of failure of the first assembly 100, the second assembly 200 is optionally added. For example, a (third) pressure sensor can be installed in the pressure connection between the two assemblies 100, 200 to detect the driver's input (preferably upstream of the isolation valve 26 in the second assembly 200). Then, when pressure builds up in the master brake cylinder 1, the activation valve 26 is closed, and the second pressure source 2 builds up pressure in all wheel brakes 8a-8d.

[0138] Optionally, the pressure connection of the two structural units 100, 200 can also be connected to a second simulator (pedal feel simulator) via a second simulator valve, which is preferably closed when de-energized, wherein the second simulator valve and the second simulator are arranged in the second structural unit 200.

Claims

Patent claims 1. Braking system for a motor vehicle for at least two hydraulically operated wheel brakes (8a-8d), comprising • a first assembly (100) in which a first electrically actuated pressure source (5) and a master brake cylinder (1) which can be actuated by means of a brake pedal (12) are arranged, • a second assembly (200) in which a second electrically actuated pressure source (2) and at least one electrically actuated inlet valve (6a-6d) per wheel brake are arranged, wherein the second electrically actuated pressure source (2) is hydraulically connected to the inlet valves (6a-6d), characterized in that the first assembly (100) comprises at most one pressure port (60) for transmitting brake pressure to actuate the wheel brakes (8a-8d) to the second assembly (200), wherein the first pressure source (5) and the master brake cylinder (1) are connected to the pressure port (60) via a system pressure line (38).

2. Brake system according to claim 1, characterized in that all inlet valves (6a-6d) are connected to the single pressure port (60) of the first assembly (100).

3. Brake system according to claim 1 or 2, characterized in that the first assembly (100) and the second assembly (200) are connected to each other by at most one pressure-resistant hydraulic connecting element (80), wherein the pressure-resistant hydraulic connecting element (80) is connected to the pressure port (60) of the first assembly (100).

4. Brake system according to one of the preceding claims, characterized in that the first assembly (100) comprises, in addition to an electrically actuated isolating valve (23) via which the master brake cylinder (1) is connected to the system pressure line (38), an electrically actuated switching valve (27) via which the first pressure source (5) is connected to the The brake system according to one of the preceding claims is characterized in that the first assembly (100) additionally comprises a compensating connection (63) for connection to a pressure medium reservoir (4), which is located at atmospheric pressure and is arranged, in particular on the first assembly (100). The pressure connection (60) is connected to a system pressure line (38) and an electrically actuated simulator valve (28), via which the master brake cylinder (1) is hydraulically connected to a simulator (3) arranged in the first assembly (100), and does not include a further electrically actuated valve. The brake system according to one of the preceding claims is characterized in that the pressure connection (60) is connected to a pressure medium reservoir (4) located at atmospheric pressure when the brake pedal (12) is not actuated and the first assembly (100) is de-energized, in particular via at least one vent hole of the master brake cylinder (1).A brake system according to one of the preceding claims, characterized in that the second assembly (200) for connection to the wheel brakes (8a-8d) comprises a hydraulic wheel connection (9a-9d) for each wheel brake, a compensating connection (62) for connection to a pressure medium reservoir (4), in particular arranged on the first assembly (100), and, in particular, only a pressure connection (61) for connection to the first assembly (100), wherein the pressure connection (61) of the second assembly (200) is connected to the pressure connection (60) of the first assembly (100). A brake system according to claim 7, characterized in that the compensating connection (63) of the first assembly (100) and the compensating connection (62) of the second assembly (200) are connected to different chambers (401, 402) of the pressure medium reservoir (4). A brake system according to claim 7 or 8, characterized in that in the second assembly (200) a brake supply line (13) connects the at least two inlet valves (6a-6d) to the pressure port (61) of the second assembly (200) and to the second pressure source (2). A brake system according to claim 9, characterized in that the pressure port (60) of the first assembly (100) is connected to the brake supply line (13) via an electrically actuated second isolating valve (26) arranged in the second assembly (200).Brake system according to claim 9 or 10, characterized in that an electrically actuated circuit separating valve (40) arranged in the second assembly (200) is arranged in the brake supply line (13) such that when the circuit separating valve (40) is closed, the brake supply line (13) is hydraulically separated into a first line section (13a) and a second line section (13b), wherein the first line section (13a) is hydraulically connected to the second pressure source (2) and at least one of the at least two inlet valves (6a, 6b) and the second line section (13b) is hydraulically connected to the pressure port (60) of the first assembly (100) and the other of the at least two inlet valves (6c, 6d). Brake system according to one of claims 9 to 11, characterized in that a pressure sensor (19) is arranged in the second assembly (200) which determines a pressure in the brake supply line (13).Brake system according to one of the preceding claims, characterized in that the first assembly (100) is designed as an assembly according to one of claims 14 to 19. Assembly (100) for a brake system for at least two hydraulically actuated wheel brakes (8a-8d), in which a first electrically actuated pressure source (5) and a master brake cylinder (1) are arranged. The assembly (100) is arranged so that the brake pedal (12) can be actuated, characterized in that the assembly comprises at most one pressure port (60) for transmitting brake pressure to the wheel brakes (8a-8d), wherein the first pressure source (5) and the master brake cylinder (1) are connected to the pressure port (60) via a system pressure line (38). The assembly (100) according to claim 14, characterized in that the pressure source (5) is connected to the pressure port (60) via an electrically actuated switching valve (27). The assembly (100) according to claim 14 or 15, characterized in that it comprises a simulator (3) which is connected to the master brake cylinder (1) via an electrically actuated simulator valve (28), and that the master brake cylinder (1) is connected to the pressure port (60) via an electrically actuated isolating valve (23).Assembly (100) according to claim 16, characterized in that no further electrically actuated valve is arranged in the hydraulic connection between the master brake cylinder (1) and the pressure port (60) in addition to the isolating valve (23). Assembly (100) according to claim 16 or 17, characterized in that the assembly (100) does not comprise any further electrically actuated valve in addition to the isolating valve (23), the switching valve (27), and the simulator valve (28). Assembly (100) according to any one of claims 14 to 18, characterized in that it is designed such that, when the brake pedal (12) is not actuated and the assembly (100) is de-energized, the pressure port (60) is connected to a compensating port (63) of the assembly (100) for connection to a hydraulic fluid reservoir (4).

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