Actuating device for a fully or partially hydraulic braking system for a vehicle

Description

[0001] The present invention relates to an actuating device for a fully or partially hydraulically acting braking system for a vehicle, comprising a master brake cylinder having a piston-cylinder unit with a piston and a working chamber, wherein the working chamber is hydraulically connected or connectable to a reservoir and a pedal feel simulator and is mechanically connected via an actuating device, in particular a brake pedal, and the working chamber is connectable to at least one brake circuit via at least one normally open valve, and that at least one hydraulically acting wheel brake assigned to a brake circuit, each of which is assigned at least one dedicated controllable switching valve, with which the wheel brake is connectable to the respective brake circuit for pressure build-up and pressure reduction, in particular in brake booster mode, as well as a pressure supply driven by an electric motor,whose piston is adjustable by means of the electric motor in the cylinder, at least one valve arrangement with solenoid valves for wheel-individual pressure control, and at least one electrical control unit for controlling at least valves of the valve arrangement and the motor of the pressure supply, as well as at least one controlled outlet valve, via which hydraulic medium can be directly discharged from the respective wheel brake or the brake circuit into the reservoir, in particular during ABS function or control operation. State of the art

[0002] The requirements, especially safety requirements, of semi-automated (HAD) and fully automated (FAD) driving have a major impact on system design. These require redundant and partially redundant systems and components.

[0003] The focus here is on the pressure supply, where braking force or pressure buildup must be ensured even without the driver's foot. The electronic control system must also be designed accordingly for this function. For Level 3, and especially Level 4, ABS functionality must also be guaranteed even in the event of a fault.

[0004] Braking systems for motor vehicles are known from the publications WO 2016 / 120292 A1, DE 10 2013 224 783 A1, WO 2017 / 055152 A1 and US 2012 / 235469 A1.

[0005] With a redundant pressure supply, a system concept can also be implemented without a tandem hydraulic cylinder, with only an e-pedal, or for Level 5, with only a brake switch. The following patent applications are worth mentioning in this regard: DE 10 2017 222 450 discloses a hydraulic system with only one master cylinder, redundant pressure supply, isolation valves to the master cylinder, and a travel simulator. A bypass valve between the two brake circuits allows the second pressure supply to supply both brake circuits in the event of a pressure supply failure. This normally open valve is extremely safety-relevant, since a valve failure, for example, resulting in a brake circuit failure, can result in total brake failure. Furthermore, the valve complexity is very high.

[0006] DE 10 2017 222 435 and DE 10 2016 225 537 demonstrate a similar concept, but with an electric pedal, reduced pressure supply, and a bypass valve. All systems use a so-called outlet valve for the ABS function during pressure reduction. If a dirt particle gets caught in the valve seat when the valve opens, this can cause a brake circuit failure during the next braking application.

[0007] DE 10 2017 207 954 shows a system concept with redundant pressure supply and no outlet valves for ABS pressure control. This uses the so-called multiplex process, already described in DE 102005055751 and DE 102009008944 A1. The pressure control for ABS is carried out by the pressure supply using volume measurement and pressure information. The switching valves for pressure control are also used redundantly. A safety risk arises if the piston seal or a check valve to the reservoir fails and the switching valve leaks due to dirt particles, which also results in total brake failure.

[0008] The above examples show the problem of dormant errors, which become critical in the case of double errors if they cannot be detected by the diagnosis before the braking maneuver.

[0009] The packaging or overall volume of the braking system is also of great importance. Particularly for systems with HAD (semi-automated) and FAD (fully automated driving), many variants from Level 2 with a tandem master cylinder (THZ) or single master cylinder (HZ) to Level 5 without a THZ or HZ must be considered in the design. In particular, 3-5 concepts with two pressure supplies or pressure supply devices (DV) are difficult to implement in packaging with a small overall volume. Examples of packaging are known from EP 2744691 with a vertical arrangement of the pressure supply (DV) to the HZ axis and DE 2016032116160400 with a parallel arrangement of the pressure supply device to the HZ axis, which require a smaller overall width. A simple master brake cylinder generally requires a braking system with multiple redundancies.This can be achieved if, for example, the master brake cylinder is designed with redundant and diagnosable seals, and if further redundancies are provided in the pressure supply (e.g. pressure supply with 2x3 phase connection, red. on-board power supply connection) and, in particular, if further modules can be used for braking (e.g. electric parking brake, electric drive motor).

[0010] From DE102016105232 A1 a packaging with a small construction volume is already known, in which an integrated redundant pressure supply consisting of at least one pressure supply device, with valves, in particular solenoid valves combined in a hydraulic unit, with at least one electronic control and regulating unit, at least one reservoir, and a master brake cylinder is combined in one module. Object of the invention

[0011] The object of the present invention is to create a very cost-effective, short and narrow 1-box solution for automated driving of levels 2 to 3, which is also modular for other solutions based on it with later integration of a second pressure supply. Advantages of the invention

[0012] This object is achieved by a system having the features of claim 1. Advantageous embodiments of the system according to claim 1 result from the features of the subclaims.

[0013] A compact package with an integrated pressure supply is proposed, consisting of a pressure supply device, valves, in particular solenoid valves, combined in a hydraulic unit, at least one electronic control and regulation unit, at least one reservoir, a single master brake cylinder, pedal stroke sensors, and a travel simulator with pistons. The invention provides various variants of modular actuation systems for brake systems, which contain as many identical parts as possible for production and assembly.

[0014] Possible variants according to the invention are preferably: Variant a: A 1-box solution with just one module, which comprises a pressure supply device, the valve arrangement (HCU), control and regulation unit (ECU) and storage container (VB). Variant b: A 1-box solution with just one module, which has the pressure supply device, wherein at least one pressure supply device is redundant, e.g. with a double on-board power supply connection or redundant phase windings, and in which the valve arrangement (HCU), control and regulation unit (ECU) and storage container (VB) are also included in the module. Variant c: Same module as in variant c, but with a control and regulation unit which is fully or partially redundant. Variant d: Use of an electric drive motor and / or an electric parking brake for braking, particularly in the event of module / subsystem failure.

[0015] The housings described below are ideal for this purpose. These housings form assemblies that, when assembled, form the complete unit for installation in the vehicle: Housing A: Contains the valve assembly (HCU) for the pressure supply unit DV1 with, for example, valves (V), solenoid valves (MV), and one or more pressure sensors (DG). Housing B: Contains the control and regulation unit (ECU) without redundancy with one main connector or with partial or full redundancy with two connectors to the vehicle electrical system. Housing C: For HZ with pedal stroke sensors and a small sensor ECU and reservoir VB for variant e. The HZ also includes the pedal interface (PI) for the brake pedal and a travel simulator with piston and spring.

[0016] Housing A (HCU) is preferably manufactured from an extruded molded piece, which is very suitable for fastening and assembly using caulking technology. The DV1 with piston drive and ball screw to the engine, as well as the valves and solenoid valves, are to be integrated here. The interface to the ECU control unit is similar to ABS / ESP. The HZ master brake cylinder with all of the aforementioned components (housing C) can be screwed to housing A - this applies to all variants except variants e and f. Here, housing C is mounted as an assembly separate from the unit on the bulkhead, and the hydraulic line from the HZ master brake cylinder is connected to housing A. In variants a. and d., the VB reservoir is located in housing A with two connections to the brake circuits or with an additional connection to the DV pressure supply. The float in the VB reservoir contains a target with a connection to the sensor element in the ECU control unit.The motor can preferably be connected to housing A via an intermediate housing, which is preferably made of plastic. The sensor required for motor commutation and piston position can preferably be mounted on the motor axis on the side of the motor housing opposite the piston and connected to the control and regulation unit (ECU). The sensor is located in an additional housing to the ECU. As redundancy for the electrical connection of the solenoid coil of the solenoid valve, an additional small circuit board can be used in addition to the main circuit board (PCB) for a second connection of the solenoid coil.

[0017] The packaging presented meets the requirements for modularity and small construction volume and is also very low in cost and weight.

[0018] By providing a special sensor housing, it is possible to easily compensate for the manufacturing tolerances of the housing of the unit according to the invention, so that the engine sensor can be safely placed in the position intended for it.

[0019] In addition, a special design of the reservoir allows its filler neck or opening to be advantageously positioned at or in front of the front of the housing of the electronic control unit or the actuating device, so that it is easily accessible. The connection from the front filler neck, which runs along the side of the housing of the electronic control unit to the rear of the housing of the control unit, allows the actual reservoir to be conveniently positioned behind the control unit. The side or central area of ​​the reservoir can advantageously be designed to be narrow, so that the actuating device is not, or only slightly, wider than with a conventional reservoir.

[0020] Each wheel brake is assigned a switching valve. Unless additional outlet valves are provided, the corresponding switching valve must be opened to change the pressure in the respective wheel brake, with the pressure supply device increasing or decreasing the pressure by moving its piston accordingly. As soon as the pressure in the wheel brake is regulated, the corresponding switching valve is closed again, and a pressure change can be made in another wheel brake.

[0021] By providing at least one outlet valve for at least one wheel brake or brake circuit, it is possible to provide a highly dynamic ESP and / or ABS function with just one pressure supply device, with pressure being built up via the switching valves assigned to the wheel brakes. The outlet valve assigned to a wheel brake can then be used to directly release the pressure into the reservoir when the wheel brake switching valve is closed, allowing a pressure change in another wheel brake or the other brake circuit to be made simultaneously with the pressure supply device.

[0022] Outlet valves should be installed particularly on hydraulic consumers with large volumes (e.g. on wheel brakes of the front axle) or at a central location between isolation valves that separate the brake circuits ( Fig. 5). Depending on the brake circuit design (diagonal or black-and-white), the outlet valves are arranged at different locations in the hydraulic system.

[0023] In brake boost mode and recuperation mode, pressure is built up and reduced via the pressure supply by the forward and backward movement of the piston; the outlet valves are operated closed here. In normal operation, e.g. with ABS, the multiplex process according to DE 102005055751 and DE 102009008944 A1 is primarily used. Only under extreme dynamic requirements is the outlet valve(s) used to reduce pressure, with the pressure reduction preferably taking place with the support of the signal from the pressure sensor. This means that the brake circuit is only opened to the reservoir in very few cases, which has decisive advantages in terms of reliability. In addition, the switching valves are arranged in such a way that a pressure present in a wheel brake (RB) applies force to the valve actuator of the switching valve (SV) away from its valve seat.

[0024] If additional volume is required for the pressure supply, volume is supplied from the reservoir to the brake circuit when the pressure supply isolating valve is closed.

[0025] Below, various variants are explained in more detail using drawings.

[0026] They show: Fig. 1: Side view of an integrated unit according to the invention with the housings A, B, C and reservoir VB and pedal interface (PI); Fig. 1a: A cross-sectional view through the motor housing, the electronic control unit and the sensor housing; Fig. 1b: Space-saving schematic design of a reservoir; Fig. 1c: Reservoir according to Figure 7 with schematically illustrated housing of the electronic control unit and the housing for the valve arrangement; Fig. 2: an alternative embodiment to the design of the 1-box module according to Figure 1 ; Fig. 2a: Front view of the Figure 2illustrated module; Fig. 3: Section through the master brake cylinder HZ, travel simulator WS and PI; Fig. 4: Illustration of the pedal stroke sensors; Fig. 5: A possible embodiment of a hydraulic system according to the invention with a fail-safe valve arrangement for connecting both brake circuits, a master cylinder with actuating device and with only one pressure supply device with electronic control and regulating device as a so-called integrated 1-box system; Fig. 6: Hydraulic system with only one pressure supply, which, however, has a redundant motor control; Fig. 6a: Hydraulic system according to Figure 6, but with a pressure supply device with double-acting pistons; Fig. 7: a schematic representation of a possible embodiment of a braking system with wheel brakes on the front axle and rear axle, with an electric drive motor driving the rear axle; Figs. 8-10: further variants of possible braking systems; Fig. 11a: black and white arrangement of the exhaust valves; Fig. 11b: diagonal arrangement of the exhaust valves.

[0027] Fig. 1shows the side view of the integrated unit housing A with valve arrangement HCU, which contains the components MV, pressure sensor DG, piston for DV1 and fastening of the motor of DV1. The components such as valves, solenoid valve MV, pressure sensor DG are preferably fastened to a flow-pressed or extruded block 24, e.g. the MV preferably by caulking or clinching, which also includes its sealing. The lower part shows the piston 8 of the pressure supply unit DV1 with return spring and housing cover 7, which is preferably driven, for example, by a spindle and ball screw drive KGT (not shown) via the motor 2. In housing A, this is screwed to the HCU block 24 via an intermediate housing 3 with fastening screws. The storage tank VB2 is connected to the brake circuits 1 and 2 with two connections 9a and 9b. The suction valve SV for the pressure supply DV is located in the housing as an extension of 9c.

[0028] The reservoir VB has a filler neck VB V with a filler opening 100 which can be closed by means of a cover 101 and which extends in front of the housing of the ECU, wherein a central area VB M extends laterally on the housing of the ECU to the rear of the unit and opens into a rear area of ​​the reservoir VB H, so that hydraulic medium can pass from the filler neck VB V into the rear area VBH.

[0029] On the opposite side, the sensor housing 3 with the angle of rotation sensor is connected to both the motor 2 and the ECU 18 via a preferably flexible circuit board (not shown) with the intermediate housing. The connectors are located on the top side of the control and regulation unit ECU; in the redundant ECU, there are two connectors. In the variant with a separate master brake cylinder HZ, the corresponding connecting line to the master brake cylinder HZ is provided at 11. The reservoir VB can, as usual, contain a level sensor (NS) with a float, whereby the target with the sensor element is arranged in the control and regulation unit ECU, which is preferably designed redundantly for levels 4 and 5. In the fully integrated version, the master brake cylinder HZ is arranged behind the valve arrangement block HCU and is screwed to the HCU block 24 with fastening screws 13.

[0030] An important component of an electric motor drive is the motor sensor 34 for electronic commutation and control of the piston position. The motor can be equipped with various drive types, e.g., gear, trapezoidal, or spindle 57 with ball screw 58, as shown in Fig. 1a shown, combined.

[0031] Various sensor types can be used, such as segment sensors with inductive or magnetic field sensitive sensors, or sensors that are arranged in the engine or transmission axis. These sensors are particularly simple in design and consist of a sensor target, e.g. in the form of a two- or multi-pole magnet, and a magnetic field sensitive sensor element, e.g. in the form of a Hall sensor, GMR sensor, or similar. This sensor element 34 is electrically connected to the electronic control unit ECU, which is attached to the engine either directly or via an intermediate housing. The sensor element 34 is preferably housed in a sensor housing comprising an outer housing part 52 and an inner housing part 52a and accommodates, among other things, a printed circuit board 22 on which the sensor element 34 can be arranged.

[0032] In order to cope with the various installation tolerances between the housing 18 of the electronic control unit ECU, the motor housing 62 and possibly an intermediate housing (not shown) and the sensor housing 52 / 52a, an elastic part 61 is provided according to the invention. In extreme cases, tolerances in all three directions x, y, z must be compensated for. This is achieved according to the invention by a corresponding construction and fastening of the sensor housing to the housing 18 of the electronic control unit ECU and to the motor housing. The sensor housing is advantageously divided into two parts: an outer housing 52 and an inner housing 52a, with the housing parts 52, 52a being connected to one another using conventional joining techniques such as welding or gluing and are preferably made of plastic. The sensor housing is also fastened to the motor housing 62, preferably at two points.The sensor circuit board 22 is flexible in its upper section to the connector strip to accommodate the aforementioned tolerances. A flex PCB (flexible printed circuit board), for example, is suitable for this purpose. The electrical connection 22a from this flexible circuit board 22 to the main circuit board 23 of the electronic control unit (ECU) is preferably made via the particularly fail-safe connector strip 51 with press-in contacts. For mounting to the main circuit board 23, the housing 18 of the electronic control unit (ECU) has a recess with a cover.

[0033] The sensor housing 52, 52a is connected to a projection of the ECU housing 18 and fixed thereto. An elastic part 61, which can be, for example, a flexible elastic seal or a sealing bellows, is located between them. The elastic part is preferably designed as a lip seal. This flexible and elastic seal 61 thus serves to compensate for 3-axis tolerances. The electrical connection from the motor winding to the circuit board 23 is established via a standard plug-in contact.

[0034] These in Figure 1aThe sensor arrangement shown additionally enables the measurement of the rotor eccentricity, which acts on the spindle and generates transverse forces on the piston 8. A measuring device 53 arranged on the rotor or the spindle nut 56, which in the simplest case is a measuring flange or a disk, is used to measure the rotor eccentricity. The rotor eccentricity also has an effect in the axial direction and can be measured using laser technology. For this purpose, the outer sensor housing part 52a has an opening 152 in its lower region 52", which is closed with a sealing plug 54 after the measurement. The surface of the measuring device 53 can have markings for the measurement on its side facing the outer sensor housing part 52, can be provided with a coating and / or be profiled. The lower region 52" is fastened to the motor housing 62 by means of a fastening screw 55.

[0035] The Figure 1bshows a space-saving schematic design of a storage container VB, which has a front area VB V , a middle area VBM and a rear area VB H. The front area VB V has an upper filling opening 100, which can be closed with the lid 101. As in Figure 1c As shown, the reservoir VB surrounds the housing B of the electronic control unit ECU on three sides, namely its front side ECU-V, its side wall ECU-S, and its rear side ECU-H. The rear side ECU-H faces the splash guard SW. Depending on the design of the unit, the reservoir VB can also rest against the rear wall of the housing of the valve assembly HCU or engage behind it, as shown in Figure 7a.

[0036] Figure 2 shows a slightly modified embodiment compared to the unit shown in Figure 1.

[0037] Figure 2ashows the view from the front. Here it is shown that the outline can still be accommodated within the small vacuum of 8" and is therefore suitable for installation on the firewall. The major advantage is the overall width of approx. 50% of the above-mentioned BKV, which is very advantageous for right- and left-hand drive vehicles. The overall length compared to the above-mentioned BKV is also considerably shorter, thus forming a basis for widespread application of the inventive modular concept. Here again, the various housings A, B, C and VB are to be provided. Housing B, for example, is located behind the HCU block 24 and is bolted to it and sealed, as with ABS.

[0038] For cost reasons, it is advantageous to use a single-piece PCB. In the event of water ingress, the PCBs can be separated by sealed bridges in the control and regulation ECU housing with the two redundant circuits. Redundancies also advantageously cover or eliminate potential circuit breakage. The remaining electronic connections from the motor to the PCB are also important.

[0039] Fig. 3shows the HZ master brake cylinder with housing, in which the HZ piston 33 and WS piston with spring for the counterforce and pedal characteristics are installed. The travel simulator piston can also be housed in block A or housing A. The piston also has redundant seals 45 with a throttle Dr to the interior. If seal 45 fails, the failure is detected via the leakage flow and the failure is no longer relevant. This throttle Dr with a small leakage flow allows the diagnosis of the failure of the first seal. The travel simulator piston is supported on flange 12 and therefore does not require a separate closure piece. The HZ piston 23 with return spring 50 is arranged parallel to the travel simulator piston. The piston can be guided in sliding rings 48 with low friction, which also has a lesser impact on the sealing effect of the piston.Preferably, a separate bearing part 49 is used for the sliding rings and seals. This bearing part is supported on the flange and also supports the stop of the piston 23 by means of a stop ring 28. For diagnostics of the travel simulator WS, a force-displacement sensor KWS 30 can be installed in the HZ piston. Sensor rods 31 and 31a are connected to the piston 23 and the pedal tappet. These rods are connected to a locking coupling 32-34, each connected to the piston and pedal tappet. This coupling consists of a ball 34 with a spring 33 in the housing 22. This prevents the pedal tappet from becoming blocked if a sensor rod jams.

[0040] Fig. 4shows the arrangement of two alternative designs for the pedal travel sensors. The first variant, with rack 38, gear 37, drive shaft 36 to target 35, and sensor element 34 on PCB 23, was already described in DE102015104246. This version requires little installation space and is cost-effective. In the lower variant, a guide part 39, e.g., with a pin, is pressed into the sensor rod. This is guided in the upper part in a guide rail 40 to minimize angular rotation, which affects the target 41. This target acts on an inductive sensor 42 with evaluation circuitry and is connected to the main PCB 23 and located in the ECU housing 14.

[0041] For variants a to f described above, the following components can advantageously be designed in the same way: DV1: for all variants a to f; DV2: for all variants with redundant pressure supply; HCU / ECU: for the two variants without redundant pressure supply; HZ and WS: Separate and integrated with pedal sensors for five of the six variants, with the exception of variant f, which has no master brake cylinder. Separate master cylinder but with additional brake disc. MV: for all variants Engine sensor: for all variants.

[0042] With the exception of the System f e-pedal, all components are modular. This provides manufacturers and users with a modular system (OEM) that provides an excellent basis for cost minimization.

[0043] The Figure 5 shows the basic elements of a controllable braking system consisting of a master brake cylinder (HZ) with a travel simulator (WS) and a reservoir (VB), a pressure supply device (DV1), where the pressure supply device (DV1) is an electromotive piston control. The pressure supply device (DV1) acts together with a valve circuit on the wheel brake cylinders (RZ), which transmit the controlled wheel pressure, e.g., in the case of ABS, to the brake. This corresponds to the state of the art. Using the single pressure supply device (DV1), the pressure can be regulated via the two connecting valves (BP1 and BP2) in both brake circuits (BK1 and BK2).

[0044] However, the hydraulic system according to the invention should have a high level of fault tolerance for semi-automatic (HAD) or fully automatic driving (FAD).

[0045] For this purpose, all components susceptible to failure should be considered, such as valves, sensors, seals, motors, and brake circuits. Therefore, the following components and hydraulic connections should advantageously be designed to be fail-safe: (1) Connection from the pressure supply device DV1 provided for the first brake circuit to the second brake circuit BK2; (2) Connection from the pressure chamber of the master brake cylinder HZ via the valve FV to the brake circuits BK1, BK2 via the valves BP1 and BP2; (3) Connection from valve PD1 and valve BD1 to the wheel brake cylinders RZ via the respective switching valves SV assigned to the wheel brakes; (4) Connection from valve BD2 to the wheel brake cylinders RZ via the respective switching valves SV assigned to the wheel brakes; (5) Connection from one brake circuit BK1, BK2 to the reservoir VB; (6) Connections between brake circuits BK1, BK2 to the wheel brake cylinders RZ.

[0046] These hydraulic connections with possible failures of the individual components are described below.

[0047] The pressure supply device DV1 acts from the brake circuit BK1 into the brake circuit BK2 via the hydraulic lines 1, 2 and 5 via the switching valves SV to the wheel brakes RB. In the prior art, only a single bypass valve is used for this purpose. A valve failure can cause a total brake failure if there is also a dormant fault in another valve. The invention therefore provides two redundant valves BP1 and BP2 to enable the connection to the brake circuit BK2 from the first pressure supply device DV1. Dormant faults in the valves BP1 and BP2 are detected by the pressure sensor by short-circuiting the valves when the pressure changes. During this phase, the pressure must remain constant. If the first pressure supply device DV1 fails, e.g. if a piston seal fails, any feedback to the brake circuit BK2 is prevented via the three redundant valves BP1, BP2 and PD1.The valves are preferably normally open valves, so that in the event of a failure of the pressure supply system DV1, the master brake cylinder HZ can act on both brake circuits BK1 and BK2. If pressure is reduced by opening the valves ZAV or FV, the two connecting switching valves open automatically due to the differential pressure acting on them, without their own electrical control.

[0048] Pedal movement is measured via redundant pedal travel sensors (PS), which simultaneously act on a KWS measuring element according to WO2012 / 059175 A1. The signal from the pedal travel sensors controls the pressure supply device DV1, with the piston control causing the volume flow in the main hydraulic line 1 in the BK1 brake circuit and, via the redundant BP1 and BP2 valves, into the BK2 brake circuit. The master brake cylinder HZ can be connected to the BK1 or BK2 brake circuits via line 3, with valve FV located in line 3 to close them. This connection is only effective in the fallback level. If the line is connected to the connecting line of the two switching valves BP1 and BP2, the two valves BP1 and BP2 form a further redundancy.A usual connection from the FV directly into one of the two brake circuits BK1, BK2 would result in the brake circuit and thus the pressure supply acting on the HZ piston in the event of a leaking valve FV, which conventionally leads to the pressure supply being switched off.

[0049] Different pressures or pressure levels from the master brake cylinder and from the brake circuits BK1 and BK2 act on the FV valve. In the worst case scenario, e.g. in the event of a failure of the on-board electrical system or the ECU control and regulation unit, this can lead to an unfavorable pressure difference at the closed FV valve and the FV valve cannot open, so that a pressure reduction P ab is not possible. To prevent this, another switching valve can be connected in parallel to the FV valve, with the outputs and inputs of the valves being interchanged and connected to line 3, so that for any pressure difference it is guaranteed that at least one of the two valves opens automatically due to the differential pressure, i.e. even without current being supplied. In addition, the back pressure on the valves is advantageously reduced. If the FV valve fails or leaks, the WS travel simulator does not fail.

[0050] If a brake circuit in the wheel cylinder fails, the corresponding inlet valve (EV) or switching valve (SV) is conventionally closed, thus eliminating the failed wheel circuit. A leaking EV / SV (dormant fault) causes the brake circuit or the entire pressure supply to fail. Here, too, the valves BP2 and BP1 provide additional safety, ensuring that the pressure supply does not fail. A failure of the brake circuit (BK1) due to a malfunctioning switching valve (SV) means a failure of the pressure supply (DV1), which causes the pressure supply to all still functioning wheel brakes to be supplied via the other pressure supply device (DV2).

[0051] When the pressure supply is active, pressure is always built up via the pressure supply. For ABS control or to reduce pressure with the pressure supply device DV1, either the pressure supply or the central outlet valve ZAV can be used. Pressure is then reduced by moving the piston of the pressure supply back or by PWM operation of the ZAV. To improve the control quality when pressure is reduced via the ZAV valve, the pressure signal from the pressure sensor can be used. However, it is also possible to provide an outlet valve AV for at least one wheel brake as an alternative to or in addition to the ZAV valve. The AV is preferably used on wheel brakes with a large volume, i.e. front wheel brakes. This means that two outlet valves AV can be used instead of one outlet valve (not shown).As is usual in standard ABS systems, an outlet valve AV can be provided for each brake circuit so that the pressure in this brake circuit is reduced via the outlet valve AV and at the same time the pressure in the other brake circuit is built up / reduced by means of the pressure supply device DV1. The volume flow also goes via the valves BP1 or BP2, so that a leaking ZAV is not critical for normal operation because if the central discharge valve ZAV fails, the pressure is controlled via the pressure supply device DV1. In addition, the fault is immediately detected by the ZAV, even if it is dormant, through a pressure change or increased volume delivery of the pressure supply device DV1. For extreme safety requirements, another discharge valve can also be connected in series to the outlet valve ZAV.

[0052] The causes of failure in the master brake cylinder (HZ) and travel simulator (WS) are usually the seals. For the master brake cylinder (HZ), an additional seal D3 with a restrictor can be installed in the return line to the reservoir (VB) to enable early diagnosis of seal failure. This allows a leak to be detected via a small additional pedal movement via the pedal stroke sensors. The low stress on the HAD and FAD must be taken into account.

[0053] To diagnose the seals, many systems have a normally open solenoid valve in the return line, which is closed for diagnosis. Pressure is supplied from the pressure supply unit DV1 via the valves PD1, BP1, and EV to the master brake cylinder HZ. Diagnosis is performed via a pressure change at a constant piston position or a change in the piston position at a constant pressure. Alternatively, a combination of throttle and check valve can be used to save costs. The throttle is dimensioned so that a leak through the seal only leads to a slight increase in pedal travel within a normal braking time of approximately 10 seconds.

[0054] The same solution is also used for the WS piston with redundant seal, diagnosis as above for D3 via pedal movement. In addition, the brake booster can still be controlled even with these failed seals, albeit with changed pedal characteristics. Here too, the failure rate for the failure of two seals is extremely low, almost in the range of <10 -10< / year. The pressure supply unit DV1 can also be equipped with redundant seals, as described above for the master brake cylinder HZ, with D6 with a throttle between D6 and D5. If the suction valve is connected directly to the connection on PD1, then suction begins immediately on the piston's return stroke, with the advantage that high suction performance is achieved even at low temperatures. A failure or leak in the SV will, in extreme cases, cause the DV to fail. A compromise is to connect the SV at approximately 60% of the stroke.This allows 40% of the stroke to be achieved without the impact of a leaking piston seal, while maintaining suction within the normal temperature range. With only a small limitation mentioned above, the piston's volumetric displacement is ensured through redundancy. Furthermore, the motor can be controlled via a redundant 2x3-phase winding, so that the piston seals only fail if the ball screw jams.

[0055] The ABS function via multiplex operation MUX and the pressure supply device DV1 is carried out as described in WO 2006 / 111393 A1. Extended MUX functions are provided by a central relief valve ZAV. If, when the pressure p auf in brake circuit BK1 is built up, a pressure reduction p ab in the other brake circuit BK2 is necessary at the same time, this takes place via the central relief valve ZAV and the simultaneously closed valve BP1. As a result, the multiplex system MUX is only loaded by two wheel brakes RB1, RB2 in brake circuit BK1, i.e. a pressure build-up Pauf and pressure reduction Pab cannot occur in the wheel brakes RB1 and RB2 of brake circuit BK1 at the same time. Alternatively, a relief valve AV1, AV2 can be used in the respective brake circuit to reduce the pressure p ab in order to relieve the load on the MUX. The relief valve AV can be arranged or connected either between the switching valve SV and a connecting switching valve BP1, BP2 or between the wheel brake and the associated switching valve SV.can be connected so that pressure reduction Pab can be directly diverted via the relief valve to a reservoir VB. This is particularly useful for pressure reduction Pab in the front wheels. The central relief valve ZAV is not required with this alternative.

[0056] Typically for the above-mentioned MUX operation, pressure control is also carried out with ABS via volume measurement and via the piston movement of the pressure supply device DV1, also taking into account the pressure-volume characteristic (pV characteristic). This also enables volume metering for pressure build-up. When building up pressure p on , it is advantageous to build pressure p on serially and not simultaneously in the individual wheel brakes. The valve dimensioning and the back pressure at the valve must be taken into account, particularly with valves BP1 and BP2 when pressure builds up quickly in the wheel circuits. The back pressure of the above-mentioned valves acts as a pressure difference between the brake circuits BK1 and BK2.

[0057] The control and regulation unit (ECU) is a component of the entire system and its packaging. A redundant or partially redundant ECU is required for fail-safe operation. This partially redundant ECU can also be used for certain functions in addition to the redundant ECU. In any case, the valves are or should be driven redundantly via separate valve drivers and a disconnect switch that shuts down a failed valve driver.

[0058] For redundancy of the ECU control and regulation unit, a redundant on-board power supply connection is also required. A 48V connection can also be used to connect the motors. The advantage of 48V is greater dynamic performance. If the motor fails on the pressure supply unit DV1 at 48V, emergency operation at 12V with approximately 50% power is possible, resulting in reduced dynamic performance and cost savings. This requires the motor to be configured for 24V, for example.

[0059] Preferably, a pressure sensor DG is used in brake circuit BK2, and possibly also in BK1. If the pressure sensor fails, pressure control can be achieved via the motor current measurement and the piston position control via the pv characteristic curve.

[0060] The pressure sensor DG1 can be used as shown in the Figure 5 shown. Alternatively, it can also be replaced or supplemented by one of the two pressure sensors DG2, DG3 shown in dashed lines. The pressure sensor DG2 should advantageously be used to measure the pressure in the connecting line VL. This advantageously allows the pressure to be controlled via the outlet valve AV and the pressure sensor DG2 during pressure reduction P ab in the brake circuit BK2 if the pressure supply device DV1 in the brake circuit BK1 operates the pressure control, e.g., using a multiplexing process.

[0061] If two pressure supply devices DV1 and DV2 are used, the pressure change in brake circuit BK2 can be controlled via the pressure sensor DG2 and the second pressure supply device DV2, which is directly connected to line 5, provided the two connecting valves BP1 and BP2 are closed. The pressure supply device DV1 then controls, for example, via volume and current measurements. Calibration can be performed, for example, whenever the pressure supply device DV1 drives the pressure change in both brake circuits BK1 and BK2.

[0062] The Figures 6 and 6a The embodiments shown are slightly different from the one shown in Figure 5 modified from the embodiment shown.

[0063] Thus, in the embodiment according to Figure 6 A separating valve TVBK1 is arranged in line 4 so that the brake circuit can be separated again from the pressure supply DV1.

[0064] Fig. 6ashows the application of a dual-circuit double-acting piston, whose forward stroke feeds BK1 via V1, and the return stroke feeds BK2 via V2. Both circuits of the DHK can feed into the other brake circuit BK via BP1 and BP2. For Pab, the volume of the DHK must be discharged into the reservoir VB via valves V3 and V4, as known from WO2016 / 023994 A1 and WO2016 / 023995 A1.

[0065] The Figure 7 shows a schematic representation of a possible embodiment of a braking system with wheel brakes RB1 and RB2 on the front axle VA and the wheel brakes RB3 and RB4 on the rear axle, wherein an electric drive motor EM is provided to drive the rear axle HA.

[0066] The braking system consists of a single pressure supply unit (DV1), an actuation unit (BE), and a higher-level control and regulation unit (M-ECU). The pressure supply unit (DV1) has two independent control and regulation units (DV-ECU1 and DV-ECU2), each of which controls one of the two winding or phase systems of the drive motor of the pressure supply unit (DV1), which are formed here by three-phase systems. Additionally, redundant signal lines (DS1 and DS2) can be provided.

[0067] Switching valves are provided for connecting or disconnecting the pressure supply unit DV1 to the wheel brakes. The dashed lines represent signal transmission lines that connect the M-ECU control unit to the brake system components.

[0068] The traction motor EM communicates with the control unit M-ECU and can be used to drive as well as brake the rear axle VA.

[0069] A pressure supply device DV1 is used to build up pressure in the hydraulically acting wheel brakes RB1-RB4. This pressure supply device has an electric motor drive M1 that is controlled by the control and regulating unit DV-ECU. In addition, the pressure supply device DV1 can also have a motor current measuring device i / U, at least one temperature sensor T / U and a rotor angle sensor ▪ / U, the signals from which can be used for pressure regulation. The motor M1 drives a piston KB via a spindle drive, which is movably mounted in a cylinder of the pressure supply device DV1 and defines a pressure chamber, in order to build up, maintain or reduce pressure there. The pressure chamber is connected to the isolating valves TV1, TV2 via a hydraulic line. Thanks to the two isolating valves connected upstream of the pressure supply DV1, a brake circuit failure does not result in a total failure of the braking system.If brake circuit BK1 fails, braking force can still be generated in brake circuit BK2 using the pressure supply and the electric motor EM. If brake circuit BK2 fails, braking force can be generated in brake circuit BK1 (front axle) using the actuation unit by the driver or the pressure supply DV1. This means that the legal requirements for minimum deceleration can be met even if the brake circuit fails. Since the pressure supply is also designed redundantly, high availability can be achieved. The residual risk lies in the clamping of the spindle drive, which must be safeguarded against by appropriate quality measures. The pressure in the hydraulic line can be determined using the pressure sensor p / U. The pressure can be controlled either with the aid of the pressure sensor p / U.The pressure can also be controlled via current measurement using the motor current measuring device i / U and the angle sensor ▪ / U and a stored pressure-volume characteristic curve, since the motor torque is proportional to the pressure in the pressure chamber and also proportional to the motor current i. The motor M1 has two separate winding systems with 2x3 phases. Of course, the number of phases can be changed according to the respective requirements. If one winding system fails, the motor M1 can still be operated with reduced power. This already creates a significant level of redundancy. The control and regulating device DV-ECU can also be designed redundantly, so that, for example, an independent control and regulating device DV-ECU1 and DV-ECU2 can be provided, each of which controls a phase system of the motor M1. This means that even if one control and regulating device DV-ECU1 orDV-ECU2 the braking system can still be operated safely.

[0070] Using the isolating valves TV1, TV2, the pressure supply device DV1 can be optionally connected to or separated from the hydraulic line HL6 or the first brake circuit BK1. Using switching valves SV1 and SV2, the hydraulic lines HL1 and HL2, which are connected to the wheel brakes, can be optionally connected to the hydraulic line HL6. If pressure is to be built up in the wheel brake RB1 of the front axle VA, this is done via open valves TV and SV1, with valves AV1, SV2 and FV closed and the piston KB adjusted by the motor M1. To reduce the pressure in the wheel brake RB1, the piston KB can be retracted with the same valve switching, or the outlet valve AV1 is opened, allowing the pressure in the wheel brake RB1 to be reduced into the reservoir VB. The pressure build-up in the wheel brake RB2 occurs in a similar way. Of course, the pressure in the wheel brakes RB1 and RB2 can also be built up and released simultaneously.It is also possible to build up pressure in one wheel brake using the pressure supply device DV1 and simultaneously reduce pressure in the other wheel brake via the associated outlet valve AV. If pressure builds up only in the wheel brakes RB3 and RB4 of the second brake circuit BK2, either the isolating valve TV and / or the switching valves SV1 and SV2 must be closed and the respective switching valve SV3 or SV3 must be open. Should the pressure supply device DV1 fail, pressure can be built up in one or both brake circuits using the actuating device BE. For this purpose, the actuating device BE has a brake pedal which acts on a piston delimiting a pressure chamber. The piston then forces hydraulic medium from the pressure chamber into the brake circuit(s), thereby building up brake pressure in one or all wheel brakes. For this purpose, the switching valves are preferably designed as normally open valves.

[0071] The Figure 8 shows another possible variant, where in contrast to the Figure 7 Only one isolating valve TV1 is provided, which is located in the housing of the pressure supply device DV1. Additionally, electric parking brakes EPB are provided on the rear axle HA as an additional option for generating braking torque in the event of a fault. If the pressure supply DV1 fails, pressure can be built up in the wheel brakes RB1-RB4 in both brake circuits BK1 and BK2 by means of the master brake cylinder HZ via the normally open valve FV. If a wheel circuit fails, the respective switching valve assigned to the leak must be operated closed to prevent this from leading to a complete failure of the braking system.

[0072] The Figure 9 shows a variant in which only one isolating valve TV1 is provided, so that in contrast to the variant of the Figure 8only in the brake circuit of the front axle VA, pressure can be built up via the master brake cylinder HZ in the event of a failure of the pressure supply device DV1. The isolating valve in this variant is located in the valve arrangement HCU. In contrast to Fig.8 the failure of the pressure supply is not too critical, since an electric traction motor EM is available in the brake circuit BK2 and the actuation unit with master brake cylinder HZ is available in the brake circuit BK1 in the event of a failure of the pressure supply DV1.

[0073] The Figure 10 shows a variant in which no electric motor is mounted on an axle and only a separating valve TV1 is provided. This allows, as in the variant of Figure 9In an emergency, pressure can only be built up in the wheel brakes RB1 and RB2 in the BK1 brake circuit of the front axle VA via the master brake cylinder HZ, since the isolating valve TV1 is closed in this case to decouple the pressure supply device DV1 from the brake circuits. To ensure that the ABS and / or ESP functions can also be provided, an additional outlet valve AV1 is provided on the wheel brake RB4 of the rear axle HA, through which the pressure in the wheel brake RB4 can be released directly into the reservoir VB.

[0074] The Figures 11a and 11bshow an advantageous connection of the switching valves SV, which ensures that the switching valves SV open reliably when pressure is trapped in the wheel brakes. For this purpose, the switching valves are connected to the working chambers of the wheel brakes via their ports assigned to the valve seat, so that the pressure trapped there pushes the valve actuator away from the valve seat of the switching valve SV. Figure 11a shows the black and white arrangement and the Figure 11b the diagonal arrangement of the exhaust valves AV1 and AV2 assigned to the wheel brakes. List of reference symbols

[0075] HZ Master brake cylinder (single) a HZ Main axis of the master brake cylinder a DV1 Axis of the first pressure supply device DV1 a1 DV2 Horizontal alignment of the axis of the second pressure supply device DV2 perpendicular to the axis a DV1 of the first pressure supply device DV1 a2 DV2 Vertical alignment of the axis of the second pressure supply device DV2 perpendicular to the axis a DV1 of the first pressure supply device DV1 DVD Pressure supply HCU Hydraulic control unit ECU Electronic computing unit ECU-V Front of the ECU ECU-SSide wall of the ECU ECU-OOp of the ECU ECU-HHerear of the ECU, facing the vehicle's firewall EM Electric drive motor PIPedal interface SW / HSmithboard / bracket StConnector BKV Brake booster NSN Level sensor RZ Wheel cylinder MV Solenoid valve Dr Throttle SV Suction valve of DV1 A Housing for HCU and DV1 and optionally DV2 A1 Partial housing for HCU and DV2 A2 Partial housing for DV1 B Housing for ECU C Housing for HZ and travel simulator WS with flange a DV1Motor axis of DV1 a DV2 Motor axis of DV2 a HZ Longitudinal axis of the master brake cylinder HZ VB Reservoir VB H Rear area of ​​the reservoir VB M Middle area of ​​the reservoir VB V Front area of ​​the reservoir VA Front axle HA Rear axle 1 Pedal tappet 2 Motor 3 Intermediate housing 4 Fastening screw 5 Sensor housing 6 Angle of rotation sensor 7 Cover plate 8 Piston 9a / 9b Connections to VB 10 Connections to RZ 11 Connection to HZ 12 Flange of HZ 13 Fastening screw 14 Fastening screw to bulkhead or bracket 15 Electrical connection motor of DV2 to ECU 16 Electrical connection of DV1 motor 17 Electrical connection of angle of rotation sensor 18 ECU housing 19 Bridge with seal 20 Driver for MV 21 Connection bridge MV 22 Small PCB 22aElectrical connection of the main PCB to PCB 22 of the ECU 23Main PCB 24HCU block 25Bore for eccentric piston pump DV2 26Motor for DV2 27Outline of 8" vacuum BKV 28Stop ring for piston 29Line to VB 30KWS 31 / 31aPedal rod 32Spring housing33HZ piston 34Sensor element 35Target 36Drive shaft 37Gear 38Rack 39Guide part 40Guide bar 41Target 42Inductive sensor 43HZ housing 44WS piston 44aWS spring 45WS seal 46Sliding ring 47Connecting holes WS-HZ and HCU block 24 48Sliding rings 49Bearing part 50Return spring 51Connector strip with press-in contacts 52Sensor housing 1 52aSensor housing 2 53Measuring flange 54Closing plug 55Sensor housing fastening 56Threaded nut 57Threaded spindle 58KGT 59Piston 60Motor contact to ECU 61Housing seal 62Motor housing 63Motor bearing 64Rotor 100Opening of the storage container 101Closing lid of the storage container 152Closable opening

Claims

1. Actuating device operating completely or partially hydraulically on a vehicle brake system, having: - a main brake cylinder (HZ) with a piston-cylinder unit having a piston and a workspace, the workspace being hydraulically connected or connectable to a storage tank (VB) and a pedal feel simulator and being mechanically connected via an actuating device, in particular a brake pedal, and the workspace being connectable via at least one normally open valve (FV) to at least one brake circuit (BK1, BK2), - at least one hydraulically operating wheel brake (RB) associated with a brake circuit (BK1, BK2), with each of which at least an own controllable switching valve (SV) is associated, with which the wheel brake (RB) can be connected to the respective brake circuit (BK1, BK2) for pressure build-up (pup) and pressure reduction (pdown), in particular in brake booster operation, - a pressure supply (DV1) driven by an electric motor (2), the piston of which is adjustable in the cylinder by means of the electric motor (2), - at least one valve assembly (HCU) with solenoid valves for wheel-specific pressure regulation, - at least one electrical control unit (ECU, DV1-ECU, DV2-ECU) for controlling at least valves of the valve assembly (HCU) and the motor of the pressure supply (DV1), - at least one controlled outlet valve (AV), via which hydraulic medium can be discharged directly from the respective wheel brake (RB) or the brake circuit (BK1, BK2) into the storage tank (VB), in particular during normal operation (ABS), and - a superordinate control and regulation unit (M-ECU), characterised in that - at least one electric parking brake (EPB) and an electric drive motor (EM) are provided for driving at least one axle of the vehicle, and - the electric drive motor is configured to send signals to the superordinate control and regulation unit (M-ECU) and / or receive signals from the superordinate electric control and regulation unit (M-ECU), wherein the braking force of the parking brake and / or the torque of the electric drive motor is used to generate braking force, in particular in the event of failure of modules.

2. Actuating device according to claim 1, characterized in that a failure of modules comprises a failure of a brake circuit, a failure of a winding system of the electric motor, or a failure of an electrical control unit (ECU, DV1-ECU, DV2-ECU).

3. Actuating device according to one of the preceding claims, characterized in that at least the actuating unit (BE) and / or the pressure supply (DV) has / have at least three seals arranged parallel to one another and at least two hydraulic connecting lines to the storage tank (VB).

4. Actuating device according to one of the preceding claims, characterized in that the pressure supply (DV) has redundant phase connections, redundant signal lines and / or redundant vehicle electrical system connections.

5. Actuating device according to one of the preceding claims, characterized in that outlet valves (AV1, AV2) are provided only on the wheel brakes of the front axle (VA), and the outlet valves are arranged between the respective wheel brake and switching valve.

6. Actuating device according to one of the preceding claims, characterized in that the main brake cylinder (HZ) can be hydraulically connected to the front axle (VA) via a valve (FV) and can be disconnected from the pressure supply (DV1) and the rear-axle brake circuit (BK2) via a separation valve (TV1), and at least one electric drive motor (EM) is provided on the rear axle (HA) for brake force assistance, in particular in the event of a failure of the pressure supply (DV1) or of the brake circuit.

7. Actuating device according to one of the preceding claims, characterized in that the controllable switching valve (SV) is arranged in such a way that a pressure present in a wheel brake (RB) applies force to the valve actuator of the switching valve (SV) away from its valve seat.

8. Actuating device according to one of the preceding claims, characterized in that - the valve assembly (HCU) is arranged in a housing (A), optionally with the hydraulic part of the pressure supply (DV), for example with valves (V), solenoid valves (MV) and one or more pressure transmitters (DG); - the control and regulation unit (ECU) is arranged in a further housing (B), the control and regulation unit (ECU) optionally being designed without redundancy with a main plug or with partial or full redundancy with two plugs to form a vehicle electrical system; and / or - the main brake cylinder (HZ) is arranged in a separate housing (C), in particular with pedal stroke sensors and a small sensor ECU and the storage tank (VB), wherein the main brake cylinder (HZ) also includes, for example, a pedal interface (PI) to the brake pedal and / or travel simulator with piston and spring.

9. Actuating device according to claim 8, characterized in that, - the main brake cylinder (HZ) is screwed to the housing (A); and / or - the separate housing (C) is mounted as a group separately from the unit on an end wall and is connected to a hydraulic line from the main brake cylinder (HZ) to the housing (A).

10. Method for pressure regulation by means of an actuating device according to one of the preceding claims; wherein optionally the pressure build-up and pressure reduction in the brake booster operation takes place exclusively via the piston control of the piston-cylinder unit (DV1) and the outlet valves (AV) are closed in this operating state; characterized in that the pressure build-up and pressure reduction in the recuperation operation takes place via braking torque of the electric motors exclusively via the piston control of the piston-cylinder unit (DV1) and the outlet valves (AV) are closed in this operating state.

11. Method for pressure regulation with an active ABS or ESP function by means of an actuating device according to one of the preceding claims, characterized in that the pressure build-up takes place exclusively via the piston control of the piston-cylinder unit (DV1) in multiplex operation, and the pressure build-up and pressure reduction take place via open / closed switching valves (SV) simultaneously or successively with closed outlet valves, and / or the pressure reduction takes place via the outlet valve or valves (AV).

12. Method for braking force regulation by means of an actuating device according to one of the preceding claims, characterized in that the braking force of the parking brake and / or the torque of the electric drive motor is also used to generate braking force, in particular in the event of failure of modules.