Failsafe brake system

1. A brake system for a vehicle, comprising the following components:

at least two hydraulic brake circuits, each with at least one hydraulically acting wheel brake;

at least one pressure supply device, which is connected via a hydraulic line to one of the at least two hydraulic brake circuits;

an associated switching valve for each hydraulically acting wheel brake, each associated switching valve switchably connecting a respective hydraulically acting wheel brake to one of the at least two hydraulic brake circuits;

at least one first hydraulic connection, which is switchable by means of at least one outlet switching valve, between at least one of the at least two hydraulic brake circuits and a reservoir;

and a hydraulic brake pedal system, of which a hydraulic output is coupled, in a manner switchable by means of an infeed switching valve, to at least one of the at least two hydraulic brake circuits; and

at least one second hydraulic connection, which is switchable by means of at least one bypass switching valve and/or at least one isolating switching valve, between the at least two brake circuits,

wherein pressure reduction in the at least one hydraulically acting wheel brake is performed by opening of the at least one outlet switching valve and of the associated switching valve, wherein brake fluid volume is returned into the reservoir first through the associated switching valve and subsequently through the at least one outlet switching valve.

2. The brake system as claimed in claim 1 , wherein the at least one pressure supply device comprises a rotary pump.

3. The brake system as claimed in claim 2 , wherein the rotary pump is designed as a gear pump or as a multi-piston pump.

4. The brake system as claimed in claim 3 , wherein the pressure supply device is connected to at least one of the brake circuits via a check valve which closes toward the pressure supply device or via a solenoid valve.

5. The brake system as claimed in claim 1 , wherein the pressure supply device has a motor, wherein the motor is a brushless DC motor, which has a redundant winding and/or a connection with 2×3 phase control.

6. The brake system as claimed in claim 1 , wherein the associated switching valves are switching valves which are open when electrically deenergized, and the at least one bypass switching valve is a bypass switching valve which is open when electrically deenergized, and the at least one outlet switching valve is an outlet switching valve which is closed when electrically deenergized, and the infeed switching valve is an infeed switching valve which is open when electrically deenergized.

7. The brake system as claimed in claim 6 , wherein the associated switching valves are designed and connected such that a residual pressure in a wheel brake opens the respective associated switching valve in the electrically deenergized state.

8. The brake system as claimed in claim 1 , wherein the at least two hydraulic brake circuits have one, two or more pressure sensors.

9. The brake system as claimed in claim 1 , wherein anti-lock braking system (ABS) and/or electronic stability (ESP) control is enabled to be performed by means of at least one of the associated switching valves and the at least one outlet switching valve.

10. The brake system as claimed in claim 1 , wherein no valve is present between the at least one outlet switching valve and at least one of the associated switching valves of one of the at least two hydraulic brake circuits.

11. The brake system as claimed in claim 1 , wherein no valve is present between the bypass switching valve and at least two of the associated switching valves.

12. The brake system as claimed in claim 1 , wherein only the at least one outlet switching valve connects the brake circuits switchably to the reservoir.

13. The brake system as claimed in claim 1 , wherein each wheel brake has only the associated switching valve.

14. The brake system as claimed in claim 1 , further comprising a second outlet switching valve, which is connected directly to an output of the pressure supply device or to an associated check valve, and which switchably connects to the reservoir, wherein only the at least one outlet switching valve and the second outlet switching valve switchably connect the brake circuits to the reservoir.

15. The brake system as claimed in claim 1 , wherein the at least one bypass switching valve comprises two bypass switching valves connected in series, wherein the at least one outlet switching valve is connected to a line section between the two bypass switching valves.

16. The brake system as claimed in claim 1 , further comprising an isolating switching valve connected directly to an output of the pressure supply device or to an associated check valve and connected directly to at least one of the associated switching valves.

17. The brake system as claimed in claim 1 , wherein the hydraulic brake pedal system has a single master cylinder or a double master cylinder.