Hydraulic multi-system non-human powered brake system

Abstract

For autonomous driving, the invention proposes an electro-hydraulic multi-circuit non-human-operated brake system (1) comprising a piston-cylinder unit (9) for each brake circuit (I, II), via which the brake circuits (I, II) are connected to one common non-human-operated brake pressure generator (3). In the event of failure of an unpowered brake pressure generator (3), the unpowered brake system (1) can be operated by a hydraulic pump (18) of a slip control section (14) of the vehicle brake system (1).

Description

[Technical field]

[0001] The present invention relates to a hydraulic, multi-system, non-human-operated brake system having the features of the preamble of claim 1. [Background technology]

[0002] A hydraulic non-human-powered brake device generates hydraulic brake pressure to operate hydraulic wheel brakes without human power, for example by using an electric motor to slide a piston in a cylinder of a piston-cylinder unit via a screw transmission mechanism.

[0003] Patent Documents 1 and 2 disclose this type of non-human brake device, characterized in that the cylinder for non-human braking is formed as a dual-system cylinder leading to hydraulically separated connections of two brake circuits, like the main brake cylinder of a dual-system vehicle brake device. Like the dual-system main brake cylinder, the cylinder for non-human braking also has two pistons arranged coaxially in tandem and spaced apart from each other in the cylinder, of which the first piston, also called the primary piston or rod-equipped piston, is slid by an electric motor via a ball screw mechanism, and the second piston, also called the secondary piston or floating piston, is biased by the hydraulic brake pressure generated by the first piston, so that the second piston generates the same brake pressure. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] European Patent Application Publication No. 1970271 [Patent Document 2] European Patent Application Publication No. 2641788 Summary of the Invention

[0005] A hydraulic multi-path non-human brake system according to the invention having the features of claim 1 comprises a plurality of brake circuits each with one or more hydraulic wheel brakes and a first hydraulic non-human brake pressure generator to which the brake circuits are connected via a respective piston-cylinder unit for each brake circuit. The non-human brake system does not have to comprise a second or further non-human brake pressure generator. A first piston side of the piston of these piston-cylinder units communicates with the non-human brake pressure generator in such a way that the first piston side of the piston of the piston-cylinder unit is actuated by the hydraulic brake pressure generated by the non-human brake pressure generator. A second piston side of the piston of these piston-cylinder units, opposite to the first piston side, communicates with the respective brake circuit in such a way that the brake circuits are actuated by the brake pressure prevailing in the cylinder of the piston-cylinder unit at the second piston side. The brake pressure in these brake circuits may be the same and may be the same as the brake pressure generated by the non-human brake pressure generator, or different brake pressures may be generated in these brake circuits and / or may differ from the brake pressure generated by the non-human brake pressure generator, for example by using stepped pistons in piston-cylinder units.

[0006] The piston-cylinder unit or its piston of the unpowered braking system according to the invention hydraulically isolates the brake circuits from each other and from the first unpowered brake pressure generator.

[0007] The non-human brake device according to the invention is provided for vehicles driving autonomously on public roads up to automation levels 4 and 5. Level 4 means high automation, i.e. the driving of the vehicle is assumed by the system, which can request the vehicle driver to take over the driving of the vehicle when the driving task can no longer be fulfilled. Level 5 is the highest level and means full automation, which means that a vehicle driver is not required. Such vehicles may be devoid of a steering wheel and pedals, but does not exclude the presence of a steering wheel and pedals. The non-human brake device according to the invention can also be used for lower automation levels and for non-autonomous driving.

[0008] The dependent claims are directed to developments and advantageous configurations of the invention defined in the independent claims.

[0009] Preferably, the vehicle braking system includes a slip control section having, for example, a hydraulic pump which can be used as a redundant second non-human-operated brake pressure generator for non-human-operated generation of hydraulic brake pressure in the event of failure of the first non-human-operated brake pressure generator.

[0010] Muscle actuation of the non-human brake system according to the invention, for example by means of a muscle-actuable main brake cylinder, is not envisaged, but is not excluded by the invention. Possible, but also not essential, is a setpoint for the brake force or for the brake pressure to be generated by the non-human brake pressure generator, which setpoint can be actuated by the vehicle driver by means of an operating element, for example a foot brake pedal or a hand brake lever.

[0011] All features disclosed in the specification and in the drawings may be realized in the embodiments of the invention, either alone or in principle in any combination. Configurations of the invention that do not have all the features of a claim or an embodiment of the invention, but only one or more of them, are in principle possible.

[0012] The present invention will be explained in detail below based on an embodiment shown in the drawings. [Brief description of the drawings]

[0013] [Figure 1] 1 is a hydraulic circuit diagram of an electrohydraulic multi-system non-human-powered brake device according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] The hydraulic multi-system non-human-powered (external force) brake device 1 according to the present invention shown in the drawings is a dual-system brake device having two hydraulic brake circuits I and II. This dual-system brake device is provided for an automobile having four hydraulic wheel brakes 2, and two wheel brakes 2 are assigned to each of the brake circuits I and II.

[0015] The non-human brake device 1 according to the invention is provided for vehicles that drive autonomously on public roads up to automation levels 4 and 5. Level 4 means high automation, i.e. the driving of the vehicle is assumed by the system, which can request the vehicle driver to take over when it is no longer able to fulfill the driving tasks. Level 5 is the highest level and means full automation, which means that a vehicle driver is not required. Such vehicles may be devoid of a steering wheel and pedals, but this does not exclude their presence. The non-human brake device 1 according to the invention can also be used for lower automation levels and for vehicles that do not drive autonomously.

[0016] In order to generate hydraulic brake pressure without human power, the non-human brake device 1 includes a first non-human brake pressure generator 3, which is electrohydraulic in this embodiment. The first non-human brake pressure generator 3 has a piston-cylinder unit 4, and a piston 5 of the piston-cylinder unit 4 is slidable in a cylinder 8 of the first piston-cylinder unit 4 via a screw transmission mechanism 7 by a first electric motor 6 to generate brake pressure. The screw transmission mechanism 7 is a ball screw mechanism in this embodiment, and may generally be understood as a rotation / translation conversion transmission mechanism. For example, a planetary transmission mechanism may be arranged between the first electric motor 6 and the screw transmission mechanism 7 as a reduction transmission mechanism (not shown). Because of the first electric motor 6, the first non-human-powered brake pressure generator 3 may be understood as an electro-hydraulic non-human-powered brake pressure generator 3, and the non-human-powered brake device 1 may be understood as an electro-hydraulic non-human-powered brake device 1 because of the electro-hydraulic non-human-powered brake pressure generator 3.

[0017] To the first non-human brake pressure generator 3, i.e. to the cylinder 8 of the first piston-cylinder unit 4, two second piston-cylinder units 9 are connected hydraulically in parallel, each of which is assigned to one of the two brake circuits I, II. Both second piston-cylinder units 9 are connected to the first non-human brake pressure generator 3 in such a way that a first piston side 10 of a piston 11 of the second piston-cylinder unit 9 is actuated by the brake pressure generated by the first non-human brake pressure generator 3, and the brake circuits I, II are connected to the second piston-cylinder unit 9 in such a way that the brake circuits I, II are actuated by the hydraulic pressure prevailing in the cylinder 12 of the second piston-cylinder unit 9 at a second piston side 13 of the piston 11. That is, both second piston-cylinder units 9 assigned to the brake circuits I, II are connected to the first non-powered brake pressure generator 3, and both brake circuits I, II are connected to the second piston-cylinder units 9 assigned to both brake circuits I, II.

[0018] The pressure on the second piston side 13 of the piston 11 of the second piston-cylinder unit 9 is generated by the biasing of the first piston side 10 by the braking pressure generated by the non-human brake pressure generator 3 and in this embodiment has the same magnitude as the braking pressure generated by the non-human brake pressure generator 3. By using, for example, a stepped piston having piston surfaces of different sizes on its first and second piston sides, a pressure different from the braking pressure generated by the non-human brake pressure generator 3 can be generated on the second piston side 13 and thus in the brake circuits I, II and / or different braking pressures can be generated in both brake circuits I, II (not shown).

[0019] In this embodiment, the piston 5 of the first piston-cylinder unit 4 of the first non-manufactured brake pressure generator 3 has a larger piston surface than the piston 11 of the second piston-cylinder unit 9 assigned to both brake circuits I, II, so that a pressure-reducing transfer is performed from the first non-manufactured brake pressure generator 3 to the brake circuits I, II, and a stroke-increasing transfer is performed from the piston 5 of the first piston-cylinder unit 4 of the first non-manufactured brake pressure generator 3 to the piston 11 of the second piston-cylinder unit 9 assigned to the brake circuits I, II. This is, however, not essential to the invention.

[0020] The non-human brake device 1 comprises a slip control part 14 with an inlet valve 15 and an outlet valve 16 for each wheel brake 2. By means of the inlet valves 15 the wheel brakes 2 are connected to the cylinders 12 of the second piston-cylinder units 9, and in each brake circuit I, II a cut valve 17 is arranged between the second piston-cylinder units 9 assigned to said brake circuits I, II and the inlet valve 15. The brake circuits I, II are actuated by the brake pressure on the second piston side 13 of the piston 11 of the second piston-cylinder units 9.

[0021] By means of the outlet valves 16, the wheel brakes 2 are connected in each brake circuit I, II to the suction side of a hydraulic pump 18, both hydraulic pumps 18 of both brake circuits I, II being drivable by a common second electric motor 19. The hydraulic pumps 18 together with the second electric motor 19 form a second non-powered brake pressure generator 20. The hydraulic pumps 18, which are part of the slip control part 14, are connected at their discharge sides between the cut valve 17 and the inlet valve 15. On their suction sides, the hydraulic pumps 18 are each provided with a hydraulic accumulator 21, which intermediately stores brake fluid from the wheel brakes 2 during slip control. The suction side of the hydraulic pumps 18 is further connected by means of a suction valve 22 to the cylinder 12 of the second piston-cylinder unit 9 at its second piston side 13.

[0022] The inlet valve 15, the outlet valve 16, the cut valve 17 and the suction valve 22 are 2-port 2-position directional solenoid valves, the inlet valve 15 and the cut valve 17 being open in their non-energized basic position and the outlet valve 16 and the suction valve 22 being closed in their non-energized basic position. The slip control 14 allows wheel-individual brake pressure regulation in the wheel brakes 2. In particular slip controls, such as anti-lock braking systems, anti-slip regulation and vehicle dynamics control, are possible, for which the abbreviations ABS, ASR and FDR are common. Such slip controls are known and will not be described in detail here.

[0023] The second non-human brake pressure generator 20 with the second electric motor 19 and the hydraulic pump 18 of the slip control part 14 ensures redundancy, i.e. in case of failure of the first non-human brake pressure generator 3, the hydraulic brake pressure can be generated instead by the second non-human brake pressure generator 20. Thereby, the availability of the non-human brake device 1 according to the invention is guaranteed also in case of failure of the first non-human brake pressure generator 3, so that the non-human brake device 1 is suitable for autonomous driving.

[0024] The cylinder 8 of the first piston-cylinder unit 4 of the first non-human brake pressure generator 3 is connected to the brake fluid container 23, and the cylinder 12 of the second piston-cylinder unit 9 is connected to the brake fluid container 23 at the second piston side 13 of the piston 11 of the second piston-cylinder unit 9, so that the pistons 5, 11 overcome openings in the brake pipe line leading from the brake fluid container 23 to the cylinders 8, 12 when, at the start of their sliding, they are slid from their basic position to hydraulically isolate the cylinders 8, 12 from the brake fluid container 23, as is known in human (muscle) operated main brake cylinders, in order to generate brake pressure.

[0025] In this embodiment of the invention, the non-human brake device 1 is constructed in a modular manner. The first non-human brake pressure generator 3 and both second piston-cylinder units 9 are assigned to a first module, called here a pressure generating module 25, and the slip control part 14 is assigned to a second module, called here a pressure regulating module 26, or are accommodated in these modules 25, 26. For example, it is also possible to accommodate the first non-human brake pressure generator 3, both second piston-cylinder units 9 and the slip control part 14 in one module (not shown). The accommodation of the components of the non-human brake device 1 according to the invention in one or more modules is not essential to the invention.

[0026] For reasons of redundancy, the pressure generating module 25 and the pressure regulating module 26 each have their own current supply 27 and their own electronic control device 28, so that the availability of the non-human brake device 1 is guaranteed in the event of an error in the pressure generating module 25 or in the pressure regulating module 26 or in the slip control part 14. In the present embodiment, the current supply 27 comprises a secondary battery.

[0027] The second piston-cylinder unit 9 assigned to the brake circuits I, II has a piston return spring 29 which biases the piston 11 towards the basic position of the piston 11, which the piston 11 occupies in the cylinder 12 when the non-manual brake device 1 is not actuated and is unpressurized. Through the connection of the second piston-cylinder unit 9 to the first piston-cylinder unit 4 of the first non-manual brake pressure generator 3, the second piston-cylinder unit 9 biases the piston 5 of the first non-manual brake pressure generator 3 hydraulically towards the basic position of the piston 5 as well. The first piston-cylinder unit 4 therefore does not require and does not have a piston spring or a piston return spring in the present embodiment.

[0028] It is also possible to return the piston 5 of the first piston-cylinder unit 4 of the first non-human brake pressure generator 3 by hydraulic pressure bias by the second non-human brake pressure generator 20 .

[0029] Furthermore, in this embodiment, the piston 5 of the first piston-cylinder unit 3 of the first non-human-powered brake pressure generator 3 is coupled to a screw transmission mechanism 7 forming a rotation / translation conversion transmission mechanism so as to transmit pulling and pushing forces, and the piston 5 can also be electromechanically returned to the basic position of the piston 5 by the first electric motor 6 via the screw transmission mechanism 7.

[0030] As a setpoint for the brake pressure to be generated by the first non-human brake pressure generator 3, the non-human brake device 1 comprises a spring-loaded foot brake pedal 30, which has a stroke sensor 31 or alternatively a force sensor. For redundancy, several stroke or force sensors or one stroke sensor 31 and one force sensor may also be provided (not shown). In principle, it is possible to provide a muscle-operable main brake cylinder (not shown) for auxiliary operation of the vehicle brake device 1 in the event of failure of the first non-human brake pressure generator 3. In the illustrated embodiment, the non-human brake device 1 does not comprise a main brake cylinder and is not muscle operable. As the brake pressure can be selectively generated by the first non-human brake pressure generator 3 or the second non-human brake pressure generator 20, the non-human brake device 1 is suitable for autonomous driving, where the non-human brake device 1 must be autonomously operable without operation by the vehicle driver, even without the possibility of muscle operation. [Explanation of symbols]

[0031] 1. Hydraulic multi-system non-human-operated brake system 2 Wheel brakes 3. First non-powered brake pressure generator 4. First piston-cylinder unit 5 Piston 6 First electric motor 7 Screw transmission mechanism 8 Cylinders 9 Second piston-cylinder unit 10 First piston side 11 Piston 12 cylinders 13 Second piston side 14 Slip control section 15 Inlet valve 16 Outlet valve 17 Cut valve 18 Hydraulic Pump 19 Second electric motor 20 Second non-powered brake pressure generator 21 Hydraulic accumulator 22 Suction valve 23 Brake fluid container 25 Pressure Generation Module 26 Pressure Regulating Module 27 Current supply section 28 Electronic control device 29 Piston return spring 30 Foot brake pedal 31 Stroke sensor I Hydraulic brake circuit II. Hydraulic brake circuit

Claims

1. A hydraulic multi-system non-human-powered brake device (1), a plurality of brake circuits (I, II) each having at least one hydraulic wheel brake (2); A first hydraulic non-powered brake pressure generator (3); In a hydraulic multi-system non-human-powered brake device (1), The non-human brake device (1) comprises a second piston-cylinder unit (9) for each of the brake circuits (I, II), and a first piston side (10) of a piston (11) of the second piston-cylinder unit (9) communicates with the first non-powered brake pressure generator (3), and a second piston side (13) of the piston (11) of the second piston-cylinder unit (9) communicates with each of the brake circuits (I, II); A hydraulic multi-system non-human-powered brake device.

2. 2. The hydraulic multi-system non-human-powered brake device according to claim 1, characterized in that the first non-human-powered brake pressure generator (3) has a first piston-cylinder unit (4), and a piston (5) of the first piston-cylinder unit (4) is slidable in a cylinder (8) of the first piston-cylinder unit (4) by a first electric motor (6) via a screw transmission mechanism (7) or a rotation / translation conversion transmission mechanism so as to generate hydraulic brake pressure non-humanly.

3. 3. The hydraulic multi-system non-human-operated brake system according to claim 1 or 2, characterized in that the non-human-operated brake system (1) includes a second non-human-operated brake pressure generator (20) by which hydraulic brake pressure can be generated alternatively to the brake pressure generated by the first non-human-operated brake pressure generator (3).

4. 4. The hydraulic multi-system non-human-powered brake system according to claim 3, wherein the brake system (1) is provided with a slip control section (14), the slip control section (14) having the second non-human-powered brake pressure generator (20).

5. 5. The hydraulic multi-system non-human brake system according to claim 3 or 4, characterized in that the non-human brake system (1) comprises a first current supply unit (27) and / or a first electronic control unit (28) for the first non-human brake pressure generator (3) and a second current supply unit (27) and / or a second electronic control unit (28) for the second non-human brake pressure generator (20).

6. 6. The hydraulic multi-system non-human-operated brake system according to claim 2, characterized in that the piston (5) of the first piston-cylinder unit (4) of the first non-human-operated brake pressure generator (3) has a piston surface larger than the piston (11) of the second piston-cylinder unit (9) communicating with the brake circuits (I, II).

7. 7. The hydraulic multi-system non-human-powered brake system according to claim 2, wherein the second piston-cylinder unit (9) communicating with the brake circuit (I, II) has a piston return spring (29), which biases the piston (11) of the second piston-cylinder unit (9) in a direction to reduce the pressure in the brake circuit (I, II) communicating with the second piston-cylinder unit (9), and / or the piston (5) of the first piston-cylinder unit (4) of the first non-human-powered brake pressure generator (3) does not have a piston spring.

8. The hydraulic multi-system non-human-powered brake device according to any one or more of claims 2 to 7, characterized in that the piston (5) of the first piston-cylinder unit (4) of the first non-human-powered brake pressure generator (3) is coupled to the screw transmission mechanism (7) or the rotation / translation conversion transmission mechanism so as to transmit a pulling force and a pushing force, and the piston (5) is slidable in the cylinder (8) of the first piston-cylinder unit (4) of the first non-human-powered brake pressure generator (3) in two opposite directions to each other via the screw transmission mechanism (7) or the rotation / translation conversion transmission mechanism by the first electric motor (6).

9. Electrohydraulic non-human operated braking device (1) according to any one or more of the preceding claims, characterized in that the non-human operated braking device (1) does not have a muscle operated part.

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