Brake system for motor vehicle

Abstract

The invention relates to a brake system for a motor vehicle, which brake system is divided into two modules, each module having a respective electrical pressure supply. A separating valve is connected in the module, the separating valve having two valve seats which can be opened at different pressure differences. This makes it possible to integrate the functions of two valves into one valve.

Description

[0001] The invention relates to a braking system for a motor vehicle.

[0002] Braking systems are generally used in motor vehicles in order to decelerate the motor vehicle in a targeted manner. Known braking systems are particularly of hydraulic design and are based on the fact that the driver operates the master brake cylinder by means of the brake pedal, and the pressure generated in the process acts directly on the wheel brakes. If necessary, this pressure can be increased, for example, by means of a known brake booster. New braking systems, for example, utilize the following principle: although pressure is generated in the master brake cylinder, the pressure is conducted to the simulator in normal braking mode, wherein the driver's braking request is only sensed by an electrically operated pressure generator and converted into a braking effect. In normal braking mode, the driver-operable master brake cylinder is therefore disconnected from the wheel brakes. Generally, only in the event of a failure in the electrical pressure supply, the originally closed valve is opened and the wheel brakes are allowed to be directly loaded with pressure by means of the master brake cylinder. In the future, the braking system is intended to be designed so that such a hydraulic backup stage can be omitted, wherein typically a corresponding redundancy must be provided in some other way. This type of braking system can also be divided into a plurality of modules.

[0003] The object of the invention is to provide a brake system for a motor vehicle which is designed alternatively or better than the known embodiments. This object is achieved according to the invention by a brake system as claimed in claim 1. Advantageous developments can be derived, for example, from the dependent claims. The contents of the claims are incorporated into the contents of the description by explicit reference.

[0004] The present invention relates to a braking system for a motor vehicle. The braking system has a first module in which at least one reservoir port and one module port are formed. The braking system has a second module in which a plurality of wheel ports are formed. The braking system has a first electrical pressure supply device, which is arranged in or on the first module, connected to the module port on the pressure side and connected to the reservoir port on the suction side. The braking system has a second electrical pressure supply device, which is arranged in or on the second module and connected to the wheel port on the pressure side. The braking system has a first separating valve, which is connected between the module port and the wheel port in the second module. The second electrical pressure supply device is connected on the pressure side to a connection between the first separating valve and at least a portion of the wheel ports.

[0005] The first separating valve has a first valve seat and a second valve seat. The first valve seat and the second valve seat are hydraulically connected in parallel. When the second valve seat is opened, it has a larger passage / throughflow than the first valve seat.

[0006] The first isolating valve is normally open. By actuating the first isolating valve, the first valve seat and the second valve seat can be closed together. The second valve seat is spring-loaded so that when the first isolating valve is not actuated, the second valve seat is opened only when the overpressure on the second electrical pressure supply device side is less than a threshold value.

[0007] The above-described design enables the implementation of a brake system that does not require a hydraulic backup stage. Two electrical pressure supplies are available that can build up pressure independently of one another. For example, if one of the electrical pressure supplies fails, the other can still generate brake pressure and thus maintain safety. By using the described first separating valve, it is achieved in a simple way to ensure that when the brake system is switched off, for example when the vehicle is stationary, the brake is set to a pressure-free state. In this case, at least the first valve seat of the first separating valve is open and thus allows a pressure reduction. As soon as the pressure difference across the first separating valve is sufficiently low, i.e., in particular below a threshold value, the first separating valve is fully opened, in particular by opening the second valve seat.

[0008] In particular, the two modules can be handled and / or placed independently of one another. The pressure supply device can be designed in particular to generate hydraulic pressure by electrical application, which can then be used in the wheel brakes to produce a braking action. In particular, the two modules can be positioned independently of one another, which increases flexibility. The first isolating valve can be used in particular to ensure that the brake fluid is supplied to the second electrical pressure supply device. This also applies in particular in the event of an electrical failure in the first module or at the first isolating valve.

[0009] A normally open design means in particular that at least one of the valve seats opens when the power supply is switched off. This may mean that the first valve seat opens. Depending on the spring-loaded design, this opening may occur independently of the existing pressure, or it may occur when the existing pressure difference drops below a predetermined value. In particular, this predetermined value may be greater than, preferably significantly greater than, a threshold value. In the case of valves known from the prior art, such a design is typically also referred to as normally open. If the second valve seat then opens, in particular after pressure equalization and at a pressure difference less than the first threshold value, this may mean that the first valve seat is thereby closed, in particular because the first valve seat forms a stop for the second valve seat. In this case, however, the second valve seat opens and the valve therefore remains open.

[0010] In particular, in order to close both valve seats, in particular to close both valve seats independently of the prevailing pressure, it is sufficient to actuate the first separating valve. It is thus possible to ensure that the valve is closed when required. The threshold value can be selected in particular by a suitable configuration of the spring which holds the valve or the second valve seat in the open state. The overpressure can first be reduced via the first valve seat, and then the second valve seat opens, so that the valve is fully opened.

[0011] Preferably, no non-return valve is provided in parallel with the first isolating valve. Such a non-return valve can advantageously be omitted, since the first isolating valve in its described design ensures that the first isolating valve is reliably opened when necessary.

[0012] According to one embodiment, the brake system further comprises a second isolating valve which is connected to the connection between the first electrical pressure supply and the first isolating valve on the one hand and is connected or connectable to the brake fluid reservoir on the other hand. This allows a direct fluid connection to the brake fluid reservoir so that pressure equalization can be achieved via the second isolating valve.

[0013] A non-return valve is connected in parallel to the second isolating valve, which has a flow direction from the brake fluid reservoir to the connection between the first electrical pressure supply and the first isolating valve. This allows an even more reliable supplementary function. In particular, the second isolating valve can be normally open. This allows a pressure reduction and / or re-suction even in the event of a power failure at the second isolating valve.

[0014] According to one embodiment, the module port is only connected to the first electrical pressure supply. The first electrical pressure supply can in particular have a compensation hole, which is only open in the non-operating state of the first electrical pressure supply, wherein the compensation hole is in particular connected to the reservoir port. This allows the pressure from the brake circuit to be reduced via the compensation hole. In particular, it can be provided that a possible overpressure from the brake circuit first displaces the piston of the first electrical pressure supply into the non-operating state, whereby the compensation hole then opens and the pressure is reduced. The non-operating state can be defined as that the piston of the second electrical pressure supply is in the fully retracted state.

[0015] According to one embodiment, one or more non-return valves are connected directly to the second electrical pressure supply on the input side, which have a flow direction to the second electrical pressure supply. According to one embodiment, one or more non-return valves are connected directly to the second electrical pressure supply on the output side, which have a flow direction away from the second electrical pressure supply. This ensures that the fluid flows through the second electrical pressure supply in the correct direction.

[0016] The first module can in particular have a control device and the second module can in particular have a second control device separate from the first control device. The control device can control the respective module. The control device can also have a divided or distributed function. In particular, the control device can be designed so that if one of the two control devices fails, the brake system remains functional at least to a limited extent. This creates redundancy.

[0017] The second electrical pressure supply can be connected, in particular via a circuit separation valve, to a connection between the first separation valve and at least a portion of the wheel ports. In particular, this can relate to the pressure side of the second electrical pressure supply. This enables the second electrical pressure supply to advantageously apply pressure to all wheel ports of the second module.

[0018] In particular, a first brake circuit and a second brake circuit can be formed in the second module. One or more wheel ports can be assigned to each brake circuit. In particular, the first brake circuit can be directly connected to the first circuit separation valve. In particular, the second brake circuit can be connected to the first brake circuit via a circuit separation valve. Therefore, the wheel port of the second brake circuit can be directly loaded with pressure by the second electrical pressure supply device. The wheel port of the first brake circuit can also be loaded with pressure via the circuit separation valve. In addition, the circuit separation valve can also be used to supply pressure from the first electrical pressure supply device to the second brake circuit, wherein the first brake circuit can typically be directly loaded with pressure by the first electrical pressure supply device via the first separation valve.

[0019] In particular, the second electrical pressure supply device can be connected directly to the second brake circuit on the pressure side. This allows the second brake circuit to be directly charged with pressure.

[0020] In particular, an inlet valve is connected between the electrical pressure supply and the wheel port, respectively. The wheel port can be connected to the suction side of the second electrical pressure supply and / or to the brake fluid reservoir or to a connection to the brake fluid reservoir via a corresponding outlet valve. The inlet valve and the outlet valve allow selective loading pressure and selective pressure reduction of each individual wheel.

[0021] According to one embodiment, the brake system also has a wiring line, which originates from the second module for direct connection to the brake fluid reservoir, which wiring line is connected to the suction side of the second electrical pressure supply device and / or to the outlet valve. This allows direct suction of the second electrical pressure supply device without the need for additional components for this purpose. In addition, when the wiring line is connected to the outlet valve, the pressure can be immediately reduced and discharged into the brake fluid reservoir.

[0022] According to an advantageous embodiment, the first electrical pressure supply device is a linear actuator. The second electrical pressure supply device is advantageously a piston pump. Linear actuators typically operate according to the hydrostatic principle, in which the displaced volume is conducted directly into the wheel brake cylinders. Piston pumps typically operate according to the fluid dynamic principle, in which a pressure is built up which is used in a suitable manner by appropriate distribution.

[0023] A person skilled in the art will be able to derive further features and advantages from the exemplary embodiments described below with reference to the accompanying drawings, in which:

[0024] Figure 1 shows a braking system according to a first exemplary embodiment,

[0025] Figure 2 shows a braking system according to a second exemplary embodiment,

[0026] Figure 3 The valve is shown.

[0027] Figure 1 A braking system BS according to a first exemplary embodiment of the invention is shown. The braking system BS comprises a first module MOD1 and a second module MOD2. The first module MOD1 has a first electronic control unit ECU1 and the second module MOD2 has a second electronic control unit ECU2. The electronic control units ECU1, ECU2 control the respective modules MOD1, MOD2 and can also implement distributed functions. In particular, they have independent power supplies and therefore in principle a failure of one of the modules MOD1, MOD2 does not lead to a failure of the respective other module MOD2, MOD1.

[0028] The first electrical pressure supply DE1 is arranged in the first module MOD1. The pressure supply is implemented here as a linear actuator. The first electrical pressure supply is connected via a non-return valve R2 to a reservoir port BA, which in turn is connected to a brake fluid reservoir BFB. This enables replenishment of the first electrical pressure supply DE1.

[0029] On the output side, the first electrical pressure supply DE1 is connected to the module port MA. The connection between the first electrical pressure supply DE1 and the module port MA is also connected to the reservoir port BA via a second isolating valve TV2, which is connected in parallel with the non-return valve R1.

[0030] The module port MA is connected to the second module MOD2 via a connecting line VL. The connecting line VL leads to a first isolating valve TV1, which is described below with reference to Figure 3 1 . The first isolating valve TV1 is connected to the first brake circuit BK1, which has two wheel ports RA1, RA2, which are each accessible via an inlet valve E1, E2 and connected to wheel brakes B1, B2. In addition, as shown in the figure, the first isolating valve TV1 and the first brake circuit BK1 are connected to the second brake circuit BK2 via a circuit isolating valve KTV. The circuit isolating valve KTV is normally open here. The second brake circuit BK2 has two further wheel ports RA3, RA4, which are accessible via corresponding inlet valves E3, E4 and connected to wheel brakes B3, B4.

[0031] The wheel ports RA are connected to the wiring line AL via respective outlet valves A1, A2, A3, A4. The wiring line leads directly to the brake fluid reservoir BFB and therefore does not need to pass through the first module MOD1. The wiring line AL is also connected to the suction side of the second electrical pressure supply DE2. The second electrical pressure supply is implemented here as a piston pump. The second electrical pressure supply DE2 has two non-return valves R3, R4 on the input side and two further non-return valves R5, R6 on the output side. As shown in the figure, the non-return valves control the flow through the second electrical pressure supply DE2 in only one direction.

[0032] Pressure sensor U / P measures the pressure in second brake circuit BK2 .

[0033] The design of the first isolating valve TV1 enables the parallel arrangement of a normally open, 2 / 2-way isolating valve and a normally closed, second, 2 / 2-way valve (optionally, a check valve) to be replaced by only one valve. The first isolating valve thus acts as a combined two-stage pressure switching and isolating valve. If an overpressure is present on the first brake circuit BK1 side, the opening of the non-actuated first isolating valve TV is ensured even in the case of high overpressure. After a certain pressure reduction, the first isolating valve TV1 opens completely, so that full throughflow is possible.

[0034] In normal braking mode, pressure loading can be performed, for example, only by means of the first electrical pressure supply device DE1, or the second electrical pressure supply device DE2 can also be used in addition. For this purpose, the first isolating valve TV1 is typically open and the second isolating valve TV2 is closed. The circuit separation valve KTV is typically open. In this case, the two pressure supply devices DE1, DE2 can act on the two brake circuits BK1, BK2 and provide a common pressure. The pressure can be conducted to the wheel port RA in a suitable manner via the inlet valves E1, E2, E3, E4. Via the outlet valve A, the pressure can be reduced again accordingly for the wheel.

[0035] If it is desired to build up pressure only by means of the second electrical pressure supply DE2, the first isolating valve TV1 can be closed. The first electrical pressure supply DE1 is thus no longer accessible. The circuit isolating valve KTV is typically open so that both brake circuits BK1 can be loaded with pressure. By closing the first isolating valve TV1, it is particularly prevented that pressure reaches the first pressure supply DE1 and it is not necessary to first push the piston against the action of the unloaded motor in order to fully use the pressure to build up at the wheel port RA.

[0036] If the second electrical pressure supply device DE2 fails, the first valve seat of the first isolating valve TV1 can open against the pressure. As a result, the brake pressure in the brake fluid reservoir BFB is reduced. This can be done in particular via the opened second isolating valve TV2. The second valve seat remains closed until the pressure is equalized, thereby allowing the second valve seat to open against the spring.

[0037] In particular, the described design enables the number of valves, coils and electrical drives to be reduced. Existing interfaces can be reused.

[0038] Figure 2 A brake system BS according to a second exemplary embodiment of the invention is shown. Compared to the first exemplary embodiment, the second separating valve TV2 is omitted. Instead, the first electrical pressure supply device DE1 has a compensating hole SL, which is directly connected to the reservoir port BA. As shown in the figure, the compensating hole SL is only accessible from the interior of the first electrical pressure supply device DE1 when the piston K of the first electrical pressure supply device DE1 is in the fully retracted position. In this embodiment, suction is possible in the same way as in the first exemplary embodiment. However, the pressure reduction from the wheel port RA to the brake fluid reservoir BFB is carried out in a different way, i.e. the pressure is reduced towards the reservoir port BA and therefore towards the brake fluid reservoir BFB via the first electrical pressure supply device DE1 and the compensating hole SL. This allows further savings, since the second separating valve TV2 can be omitted.

[0039] Figure 3 A possible embodiment of the first separating valve TV1 is shown.

[0040] The valve 5 is designed as a two-way valve in principle. Here, a normally open electromagnetically actuated pilot valve 10 is formed, which has a sleeve 11, an armature 12, a plunger 13 and a first compression spring 14. The valve has a second valve seat 20, in which the first valve seat 15 of the pilot valve 10 is integrated, and the second valve seat and the valve plate 25 form a main stage.

[0041] The housing 30 receives the valve sleeve 11 on one side and is connected on the other side to a deep-drawn lower valve housing 35. An adjusting sleeve 32 is pressed into the housing 30 in a displaceably adjustable manner, so that the air gap between the magnetic poles of the armature 12 and the housing 30 can be adjusted to compensate for component tolerances.

[0042] An inlet 6 and an outlet 7 are formed in the valve 5. For example, the inlet 6 may be connected to the first brake circuit BK1. For example, the outlet 7 may be connected to the connecting line VL.

[0043] By applying a magnetic field, which can be generated in particular by a solenoid (not shown), the armature 12 and thus also the plunger 13 can be pushed to the right. This reliably closes the two valve seats 15, 20. The valve is thus locked.

[0044] The strength of the first compression spring 14 is designed so that when the valve is not actuated, the armature 12 is in any case pushed to the left and the first valve seat 15 is therefore open. The second compression spring 24 pushes the second valve seat to the left into the open position, but is designed to be weaker. Therefore, a complete opening of the valve 5 is only possible when the overpressure at the inlet 6 relative to the outlet 7 is at most as great as a threshold value. The second valve seat 20 is then open, wherein the first valve seat 15 serves as an end stop for the associated movement and is therefore closed.

[0045] In application, this means that in principle opening of the valve 5 is ensured when it is closed, but the main part of the valve 5 must have a weaker spring load, so that a lower actuation energy is sufficient.

[0046] It should be noted that in the claims and the specification, feature combinations may be described, for example to facilitate understanding, but these features may also be used separately from each other. Those skilled in the art will recognize that these features may also be combined with other features or feature combinations independently of each other.

[0047] The dependent references in the dependent claims may characterize preferred combinations of individual features, but do not exclude other combinations of features.

[0048] List of Reference Numerals

[0049] BS Braking System

[0050] MOD Module

[0051] ECU control unit

[0052] BA Memory Port

[0053] BFB Brake Fluid Reservoir

[0054] R Check valve

[0055] DE Pressure Supply Unit

[0056] SL Compensation Hole

[0057] MA Module Ports

[0058] VL connection line

[0059] AL wiring circuit

[0060] TV Separation Valves

[0061] KTV circuit separation valve

[0062] BK brake circuit

[0063] E Inlet valve

[0064] A Outlet valve

[0065] RA Wheel Port

[0066] B Brake

[0067] U / P Pressure Sensor

[0068] 5 valves

[0069] 6 Entrance

[0070] 7 Exit

[0071] 10 Pilot valve

[0072] 11 Sleeve

[0073] 12 Armature

[0074] 13 Plunger

[0075] 14 First compression spring

[0076] 15 First valve seat

[0077] 20 Second valve seat

[0078] 24 Second compression spring

[0079] 25 Valve plate

[0080] 30 Shell

[0081] 32 Adjustment sleeve

[0082] 35 valve housing

Claims

1. A braking system (BS) for a motor vehicle, in, The braking system (BS) has: - a first module (MOD1) in which at least one reservoir port (BA) and one module port (MA) are formed, - a second module (MOD2) in which a plurality of wheel ports (RA) are formed, a first electrical pressure supply device (DE1) arranged in or on the first module (MOD1), connected on the pressure side to the module port (MA) and on the suction side to the reservoir port (BA), a second electrical pressure supply (DE2) which is arranged in or on the second module (MOD2) and is connected on the pressure side to the wheel port (RA), a first isolating valve (TV1) connected in the second module (MOD2) between the module port (MA) and the wheel port (RA), wherein a second electrical pressure supply device (DE2) is connected on the pressure side to a connection between the first separation valve (TV1) and at least a part of the wheel ports (RA), - wherein the first separating valve (TV1) comprises a first valve seat (15) and a second valve seat (20), wherein the first valve seat (15) and the second valve seat (20) are hydraulically connected in parallel, and the second valve seat (20) has a larger passage than the first valve seat (15) when it is open, - wherein the first isolating valve (TV1) is normally open, wherein the first valve seat (15) and the second valve seat (20) can be closed jointly by actuating the first separating valve (TV1), wherein the second valve seat (20) is spring-loaded in such a way that, when the first isolating valve (TV1) is not actuated, the second valve seat only opens when the overpressure on the side of the second electrical pressure supply (DE2) is less than a threshold value.

2. A braking system (BS) according to claim 1, - wherein no non-return valve is arranged in parallel with the first separating valve (TV1).

3. A braking system (BS) as claimed in any one of the preceding claims, - the braking system also has a second separating valve (TV2), which is connected on the one hand to the connection between the first electrical pressure supply device (DE1) and the first separating valve (TV1) and on the other hand is connected or can be connected to a brake fluid reservoir (BFB).

4. A braking system (BS) according to claim 3, A check valve (R1) is connected in parallel to the second isolating valve (TV2), which check valve has a flow direction from the brake fluid reservoir (BFB) to the connection between the first electrical pressure supply (DE1) and the first isolating valve (TV1).

5. A braking system (BS) according to any one of claims 3 and 4, - The second isolating valve (TV2) is normally open.

6. A braking system (BS) according to any one of claims 1 and 2, - the module port (MA) is connected only to the first electrical pressure supply (DE1), the first electrical pressure supply device has a compensation hole (SL) which is open only in the non-operating state of the first pressure supply device (DE1), - The compensating hole (SL) is connected to the reservoir port.

7. A braking system (BS) according to any one of the preceding claims, one or more non-return valves (R3, R4) are connected directly to the input side of the second electrical pressure supply device (DE2), the non-return valves (R3, R4) having a flow direction to the second electrical pressure supply device (DE2), and / or One or more non-return valves (R5, R6) are connected directly to the output side of the second electrical pressure supply device (DE2), the non-return valves having a flow direction away from the second electrical pressure supply device (DE2).

8. A braking system (BS) according to any one of the preceding claims, The first module (MOD1) has a first control device (ECU1), and the second module (MOD2) has a second control device (ECU2) which is independent of the first control device (ECU1).

9. A braking system (BS) according to any one of the preceding claims, A second electrical pressure supply (DE2) is connected via a circuit separation valve (KTV) to the connection between the first separation valve (TV1) and at least some of the wheel ports (RA).

10. A braking system (BS) according to any one of the preceding claims, A first brake circuit (BK1) and a second brake circuit (BK2) are formed in the second module (MOD2), wherein: Each brake circuit (BK1) is assigned one or more wheel ports (RA). The first brake circuit (BK1) is directly connected to the first isolating valve (TV1).

11. Braking system (BS) according to claim 9 and claim 10, The second brake circuit (BK2) is connected to the first brake circuit (BK1) via a circuit separation valve (KTV).

12. A braking system (BS) according to any one of claims 10 and 11, A second electrical pressure supply (DE2) is connected directly to the second brake circuit (BK2) on the pressure side.

13. A braking system (BS) according to any one of the preceding claims, - an inlet valve (E) is connected between the electrical pressure supply (DE1, DE2) and the wheel port (RA), and / or The wheel ports (RA) are connected via respective outlet valves (A) to the suction side of a second electrical pressure supply (DE2) and / or to a brake fluid reservoir (BFB).

14. A braking system (BS) according to any one of the preceding claims, The brake system also has a connection line (AL) which leaves the second module (MOD2) for direct connection to the brake fluid reservoir (BFB), which is connected to the suction side of the second electrical pressure supply (DE2) and / or to the outlet valve (A).

15. A braking system (BS) according to any one of the preceding claims, - the first electrical pressure supply device (DE1) is a linear actuator, and / or -in, The second electrical pressure supply device (DE2) is a piston pump.

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