A redundant electro-hydraulic brake system

Abstract

The application discloses a redundant electronic hydraulic brake system, which comprises a first brake master cylinder, a second brake master cylinder, a first normally open electromagnetic valve, a second normally open electromagnetic valve, a first normally closed electromagnetic valve, a second normally closed electromagnetic valve, a third normally closed electromagnetic valve and a normally open bidirectional balance valve. Through the design of the double brake master cylinders and the normally open electromagnetic valve and the normally closed electromagnetic valve, the redundant backup function of the brake system can be realized, braking can be realized in different failure modes, and the normal work of the brake system in the event of failure is ensured.

Description

Technical Field

[0001] This invention relates to the field of vehicle braking technology, and in particular to a redundant electro-hydraulic braking system. Background Technology

[0002] Currently, the development of electronic brake-by-wire systems in the automotive industry mainly focuses on two directions: electro-hydraulic braking systems (EHB) and electro-mechanical braking systems (EMB). EMB, because it involves no hydraulic fluid and relies entirely on mechanical structures for braking, theoretically offers superior performance. However, due to the immaturity of the technology, mature commercial products are rare. For practical reasons, the automotive industry currently prioritizes EHB systems, and EHB will remain the mainstream electronic brake-by-wire system for a considerable period.

[0003] The automotive industry is increasingly moving towards electrification and intelligentization, a trend widely considered the main direction for future automotive development. Within this broader trend, autonomous driving is a crucial component. Safety is one of the most critical performance indicators for autonomous driving, and traditional braking systems are no longer sufficient to meet its high demands. Autonomous vehicles require braking systems with redundancy and backup capabilities. This ensures that even if the braking actuator fails, the braking system can still function normally, guaranteeing driving safety and meeting the safety requirements of intelligent driving. Summary of the Invention

[0004] The purpose of this invention is to provide a redundant electro-hydraulic braking system to achieve the redundant backup function of the braking system, ensuring that the braking system can still function normally when the braking actuator fails, thereby improving driving safety.

[0005] To achieve the above objectives, the present invention provides the following solution:

[0006] This invention provides a redundant electro-hydraulic braking system, which includes a first master cylinder, a second master cylinder, a first normally open solenoid valve, a second normally open solenoid valve, a first normally closed solenoid valve, a second normally closed solenoid valve, a third normally closed solenoid valve, and a normally open bidirectional balance valve.

[0007] The vehicle's pedal is connected to the piston rod of the first piston of the first brake master cylinder, and the vehicle's displacement sensor is mounted on the piston rod of the first piston of the first brake master cylinder.

[0008] The first hydraulic chamber of the first brake master cylinder is connected to the brake fluid input terminal of the first wheel cylinder group of the vehicle through the first normally open solenoid valve; the second hydraulic chamber of the first brake master cylinder is connected to the oil supply system through the first normally closed solenoid valve; and the third hydraulic chamber of the first brake master cylinder is connected to the brake fluid input terminal of the first wheel cylinder group of the vehicle through the second normally open solenoid valve.

[0009] The first hydraulic oil chamber of the second brake master cylinder is connected to the oil supply system through a second normally closed solenoid valve; the second hydraulic oil chamber of the second brake master cylinder is connected to the brake oil input end of the second wheel cylinder group through the third normally closed solenoid valve.

[0010] The brake fluid input terminals of the first wheel cylinder group and the second wheel cylinder group are connected via the normally open bidirectional balance valve.

[0011] The control terminals of the first normally open solenoid valve, the second normally open solenoid valve, the first normally closed solenoid valve, the second normally closed solenoid valve, the third normally closed solenoid valve, and the normally open bidirectional balance valve are all connected to the vehicle's ECU.

[0012] Optionally, the first brake master cylinder includes a first hydraulic cylinder, and a first piston and a second piston located within the first hydraulic cylinder;

[0013] A baffle is provided inside the first hydraulic cylinder;

[0014] The first piston is located on one side of the partition, and a first hydraulic oil chamber of the first brake master cylinder is formed between the first piston and the partition. The piston rod of the first piston passes through one end of the first hydraulic cylinder and is connected to the pedal.

[0015] The second piston is located on the other side of the partition. The piston rod of the second piston passes through the partition and extends into the first hydraulic oil chamber of the first brake master cylinder. The second piston and the partition form the second hydraulic oil chamber of the first brake master cylinder. The second piston and the other end of the first hydraulic cylinder form the third hydraulic oil chamber of the first brake master cylinder.

[0016] Optionally, the second brake master cylinder includes a second hydraulic cylinder and a third piston located in the second hydraulic cylinder;

[0017] The third piston divides the inner cavity of the second hydraulic cylinder to form the first hydraulic oil chamber of the second brake master cylinder and the second hydraulic oil chamber of the second brake master cylinder.

[0018] Optionally, in normal braking mode, when the driver depresses the pedal, the vehicle's displacement sensor transmits the pedal displacement signal to the vehicle's ECU. The ECU then controls the first normally open solenoid valve and the normally open bidirectional balance valve to close, and controls the first normally closed solenoid valve, the second normally closed solenoid valve, the third normally closed solenoid valve, and the second normally open solenoid valve to open. Hydraulic oil in the fuel delivery system enters the second hydraulic chamber of the first brake master cylinder through the first normally closed solenoid valve, pushing the second piston of the first brake master cylinder to move. This causes the brake oil in the third hydraulic chamber of the first brake master cylinder to be injected into the first wheel cylinder group for braking through the second normally open solenoid valve. Hydraulic oil in the fuel delivery system enters the first hydraulic chamber of the second brake master cylinder through the second normally closed solenoid valve, pushing the third piston of the second brake master cylinder to move. This causes the brake oil in the second hydraulic chamber of the second brake master cylinder to be injected into the second wheel cylinder group for braking through the third normally closed solenoid valve.

[0019] Optionally, when the first brake master cylinder fails, when the driver presses the pedal, the vehicle's displacement sensor transmits the pedal displacement signal to the vehicle's ECU. The vehicle's ECU controls the first normally open solenoid valve, the second normally open solenoid valve, and the first normally closed solenoid valve to close, and controls the second normally closed solenoid valve, the third normally closed solenoid valve, and the normally open bidirectional balance valve to open.

[0020] Hydraulic oil in the oil supply system enters the first hydraulic oil chamber of the second brake master cylinder through the second normally closed solenoid valve, pushing the third piston of the second brake master cylinder to move. This causes the brake oil in the second hydraulic oil chamber of the second brake master cylinder to be injected into the second wheel cylinder group for braking through the third normally closed solenoid valve, and into the first wheel cylinder group for braking through the third normally closed solenoid valve and the normally open bidirectional balance valve.

[0021] Optionally, when the second brake master cylinder fails, when the driver presses the pedal, the vehicle's displacement sensor transmits the pedal displacement signal to the vehicle's ECU. The vehicle's ECU controls the first normally open solenoid valve, the second normally closed solenoid valve, and the third normally closed solenoid valve to close, and controls the first normally closed solenoid valve, the second normally open solenoid valve, and the normally open bidirectional balance valve to open.

[0022] Hydraulic oil in the oil supply system enters the second hydraulic oil chamber of the first brake master cylinder through the first normally closed solenoid valve, pushing the second piston of the first brake master cylinder to move. This causes the brake oil in the third hydraulic oil chamber of the first brake master cylinder to enter the first wheel cylinder group for braking through the second normally open solenoid valve, and then enters the second wheel cylinder group for braking through the second normally open solenoid valve and the normally open bidirectional balance valve.

[0023] Optionally, in electronic failure mode or first double failure mode, when the driver depresses the brake pedal, the pedal drives the first piston of the first brake master cylinder to move, directly contacting and pushing the second piston of the first brake master cylinder to move. Before the first piston contacts the second piston, brake fluid in the first hydraulic chamber of the first brake master cylinder is directly injected into the first wheel cylinder group for braking through the first normally open solenoid valve, and injected into the second wheel cylinder group for braking through the first normally open solenoid valve and the normally open bidirectional balance valve. After the first piston contacts the second piston, the first piston pushes the second piston to build up pressure, thus applying brake fluid in the third hydraulic chamber of the first brake master cylinder. The brake fluid is injected into the first wheel cylinder group through the second normally open solenoid valve, and the brake fluid in the first hydraulic oil chamber of the first brake master cylinder is injected into the first wheel cylinder group through the first normally open solenoid valve to brake the first wheel cylinder group. The brake fluid in the third hydraulic oil chamber of the first brake master cylinder is injected into the second wheel cylinder group through the second normally open solenoid valve and the normally open bidirectional balance valve, and the brake fluid in the first hydraulic oil chamber of the first brake master cylinder is injected into the second wheel cylinder group through the first normally open solenoid valve and the normally open bidirectional balance valve to brake the second wheel cylinder group. The first dual failure mode is a dual failure mode of electronic failure and second brake master cylinder failure.

[0024] Optionally, when in the second or third double failure mode, the driver depresses the brake pedal, which drives the first piston of the first brake master cylinder to move, directly injecting brake fluid from the first hydraulic chamber of the first brake master cylinder into the first wheel cylinder group for braking through the first normally open solenoid valve, and injecting it into the second wheel cylinder group for braking through the first normally open solenoid valve and the normally open bidirectional balance valve; the second double failure mode is a double failure mode of electronic failure and first brake master cylinder failure, and the third double failure mode is a double failure mode of electronic failure, first brake master cylinder failure and second brake master cylinder failure.

[0025] Optionally, the oil delivery system includes a hydraulic pump, a motor, an accumulator, and a hydraulic cylinder;

[0026] The hydraulic oil input end of the hydraulic pump is connected to the oil cylinder, the output shaft of the motor is connected to the shaft of the hydraulic pump, and the hydraulic oil output end of the hydraulic pump is connected to the accumulator.

[0027] The hydraulic oil output end of the hydraulic pump is connected to the second hydraulic oil chamber of the first brake master cylinder through a first normally closed solenoid valve, and the hydraulic oil output end of the hydraulic pump is also connected to the first hydraulic oil chamber of the second brake master cylinder through a second normally closed solenoid valve.

[0028] According to specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0029] This invention provides a redundant electro-hydraulic braking system, comprising a first master cylinder, a second master cylinder, a first normally open solenoid valve, a second normally open solenoid valve, a first normally closed solenoid valve, a second normally closed solenoid valve, a third normally closed solenoid valve, and a normally open bidirectional balance valve. Through the design of dual master cylinders and normally open and normally closed solenoid valves, this invention achieves redundant backup functionality for the braking system, enabling braking under various fault modes and ensuring normal operation of the braking system in the event of a fault. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram of a redundant electro-hydraulic braking system according to an embodiment of the present invention.

[0032] Reference numerals: 1. Pedal; 2. Pedal feel simulator; 3. First brake master cylinder; 31. First piston; 32. Second piston; 33. First hydraulic chamber of the first brake master cylinder; 34. Second hydraulic chamber of the first brake master cylinder; 35. Third hydraulic chamber of the first brake master cylinder; 4. Second brake master cylinder; 41. Third piston; 42. First hydraulic chamber of the second brake master cylinder; 43. Second hydraulic chamber of the second brake master cylinder; 6. Accumulator; 7. Hydraulic pump; 8. Motor; 9. Oil tank; 51. First normally closed solenoid valve; 52. Second normally closed solenoid valve; 10. Third normally closed solenoid valve; 11. Normally open bidirectional balance valve; 12. Second normally open solenoid valve; 13. First normally open solenoid valve; 14. Pressure booster valve; 15. Pressure reducing valve; 16. Wheel cylinder. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] The purpose of this invention is to provide a redundant electro-hydraulic braking system to achieve the redundant backup function of the braking system, ensuring that the braking system can still function normally when the braking actuator fails, thereby improving driving safety.

[0035] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0036] This invention provides a redundant electro-hydraulic braking system, such as... Figure 1 As shown, the redundant electro-hydraulic braking system includes a first master cylinder 3, a second master cylinder 4, a first normally open solenoid valve 13, a second normally open solenoid valve 12, a first normally closed solenoid valve 51, a second normally closed solenoid valve 52, a third normally closed solenoid valve 10, and a normally open bidirectional balance valve 11; the vehicle's pedal 1 is connected to the piston rod of the first piston 31 of the first master cylinder, the vehicle's pedal feel simulator 2 is installed in the first hydraulic oil chamber 33 of the first master cylinder, and the vehicle's displacement sensor is installed on the piston rod of the first piston 31 of the first master cylinder; the first hydraulic oil chamber 33 of the first master cylinder is connected to the brake oil input end of the vehicle's first wheel cylinder group through the first normally open solenoid valve 13, and the second hydraulic oil chamber 34 of the first master cylinder is connected to the oil supply system through the first normally closed solenoid valve 51. The third hydraulic chamber 35 of the brake master cylinder is connected to the brake fluid input terminal of the first wheel cylinder group of the vehicle through the second normally open solenoid valve 12; the first hydraulic chamber 42 of the second brake master cylinder is connected to the oil supply system through the second normally closed solenoid valve 52; the second hydraulic chamber 43 of the second brake master cylinder is connected to the brake fluid input terminal of the second wheel cylinder group through the third normally closed solenoid valve 10; the brake fluid input terminals of the first wheel cylinder group and the second wheel cylinder group are connected through the normally open bidirectional balance valve 11; the control terminals of the first normally open solenoid valve 13, the second normally open solenoid valve 12, the first normally closed solenoid valve 51, the second normally closed solenoid valve 52, the third normally closed solenoid valve 10, and the normally open bidirectional balance valve 11 are all connected to the vehicle's ECU.

[0037] The first master brake cylinder 3 includes a first hydraulic cylinder and a first piston 31 and a second piston 32 located within the first hydraulic cylinder. A partition is provided inside the first hydraulic cylinder. The first piston 31 is located on one side of the partition, and a first hydraulic oil chamber 33 of the first master brake cylinder is formed between the first piston 31 and the partition. The piston rod of the first piston 31 passes through one end of the first hydraulic cylinder and is connected to the pedal 1. The second piston 32 is located on the other side of the partition, and the piston rod of the second piston 32 passes through the partition and extends into the first hydraulic oil chamber 33 of the first master brake cylinder. A second hydraulic oil chamber 34 of the first master brake cylinder is formed between the second piston 32 and the partition. A third hydraulic oil chamber 35 of the first master brake cylinder is formed between the second piston and the other end of the first hydraulic cylinder.

[0038] The second brake master cylinder 4 includes a second hydraulic cylinder and a third piston 41 located in the second hydraulic cylinder; the third piston 41 divides the inner cavity of the second hydraulic cylinder to form a first hydraulic oil chamber 42 of the second brake master cylinder and a second hydraulic oil chamber 43 of the second brake master cylinder.

[0039] The oil delivery system includes an accumulator 6, a hydraulic pump 7, a motor 8, and a cylinder 9. The hydraulic oil input end of the hydraulic pump 7 is connected to the cylinder 9, and the hydraulic oil output end of the hydraulic pump 7 is connected to the accumulator 6. The output shaft of the motor 8 is connected to the hydraulic pump 7. The hydraulic oil output end of the accumulator 6 is connected to the second hydraulic oil chamber 34 of the first brake master cylinder through a first normally closed solenoid valve 51, and the hydraulic oil output end of the accumulator 6 is also connected to the first hydraulic oil chamber 42 of the second brake master cylinder through a second normally closed solenoid valve 52.

[0040] Based on the above structure, the redundant electro-hydraulic braking system provided in this embodiment of the invention can achieve safe and effective braking under different failure modes, as detailed below:

[0041] Normal braking mode: When the driver presses the brake pedal 1, the first normally open solenoid valve 13 closes, and the pedal 1 drives the first piston 31 to move. At this time, the vehicle's displacement sensor senses the displacement of the first piston 31. In this embodiment of the invention, the displacement sensor is located on the piston rod of the first piston 31 and is used to directly sense the displacement of the first piston, thereby obtaining the pedal displacement signal. The pedal displacement signal is transmitted to the vehicle's ECU, and the pedal feel simulator 2 feeds back the pedal feel to the driver. The vehicle's ECU controls the opening of the first normally closed solenoid valve 51, the second normally closed solenoid valve 52, the third normally closed solenoid valve 10, and the second normally open solenoid valve 12, while closing the normally open bidirectional balance valve 11. The motor 8 starts, driving the hydraulic pump 7 to input the hydraulic oil from the accumulator 6 through the first normally closed solenoid valve 51 and the second normally closed solenoid valve 52 into the second hydraulic oil chamber 34 of the first brake master cylinder and the first hydraulic oil chamber 42 of the second brake master cylinder, pushing the second piston 32 and the third piston 41 to move. The brake oil in the third hydraulic oil chamber 35 of the first brake master cylinder and the second hydraulic oil chamber 43 of the second brake master cylinder passes through the third normally closed solenoid valve 10 and the second normally open solenoid valve 12 and is input into the first wheel cylinder group and the second wheel cylinder group through the booster valve 14. The ECU adjusts to ensure that the wheel cylinders in the first wheel cylinder group and the second wheel cylinder group obtain the required braking force.

[0042] Mechanical failure modes: When one of the two brake cylinders, the first brake master cylinder 3 and the first brake master cylinder 4, experiences a mechanical failure, it can be divided into the following two forms.

[0043] First brake master cylinder failure mode: When the driver depresses the brake pedal 1, the first normally open solenoid valve 13 closes, and the pedal 1 drives the first piston 31 to move. At this time, the displacement sensor on the piston rod of the first piston 31 senses the displacement of the first piston 31 and obtains the pedal displacement signal, which is transmitted to the vehicle's ECU. The pedal feel simulator 2 feeds back the pedal feel to the driver. The vehicle's ECU controls the second normally closed solenoid valve 52, the third normally closed solenoid valve 10, and the normally open bidirectional balance valve 11 to open, and the first normally closed solenoid valve 51 and the second normally open solenoid valve 12 to close. The motor 8 starts, driving the hydraulic pump 7 to input the high-pressure oil from the accumulator 6 into the first hydraulic oil chamber 42 of the first brake master cylinder through the second normally closed solenoid valve 52, pushing the third piston 41 to move. The brake oil in the second hydraulic oil chamber 43 of the first brake master cylinder is input into the wheel cylinders 16 of the first and second wheel cylinder groups through the third normally closed solenoid valve 10, the normally open bidirectional balance valve 11, and the booster valve 14. The ECU adjusts to make the wheel cylinders 16 obtain the required braking force.

[0044] In the second brake master cylinder failure mode, when the driver depresses the brake pedal 1, the first normally open solenoid valve 13 closes, and the pedal 1 drives the first piston 31 to move. At this time, the displacement sensor on the piston rod of the first piston 31 senses the displacement of the first piston 31 and obtains the pedal displacement signal, which is transmitted to the vehicle's ECU. The pedal feel simulator 2 provides feedback on the pedal feel to the driver. The vehicle's ECU controls the first normally closed solenoid valve 51, the second normally open solenoid valve 12, and the normally open bidirectional balance valve 11 to open, and the second normally closed solenoid valve 52 and the third normally closed solenoid valve 10 to close. The high-pressure oil from the accumulator 6 is input into the second hydraulic oil chamber 34 of the first brake master cylinder through the first normally closed solenoid valve 51, which pushes the second piston 32 to move. The brake oil in the third hydraulic oil chamber 35 of the first brake master cylinder is input into the wheel cylinder 16 through the second normally open solenoid valve 12, the normally open bidirectional balance valve 11, and the booster valve 14. The ECU adjusts to give the wheel cylinder 16 the required braking force.

[0045] Electronic failure mode: When the system loses power.

[0046] Electronic failure mode: When the system loses power, all solenoid valves remain in their initial open / closed state. When the driver depresses the brake pedal 1, the pedal 1 drives the first piston 31 to move. After eliminating the decoupling gap between the first piston 31 and the second piston 32, the first piston 31 and the second piston 32 directly contact each other, pushing the second piston 32 to move. Before the first piston 31 contacts the second piston 32, the high-pressure brake fluid in the first hydraulic oil chamber 33 of the first brake master cylinder is directly injected into the wheel cylinder 16 through the normally open first normally open solenoid valve 13 and the normally open bidirectional balance valve 11. After the first piston 31 contacts the second piston 32, the first piston 31 pushes the second piston 32 to build up pressure. The high-pressure brake fluid in the first hydraulic oil chamber 33 and the third hydraulic oil chamber 35 of the first brake master cylinder is input into the wheel cylinder 16 through the normally open first normally open solenoid valve 13, the normally open bidirectional balance valve 11 and the normally open second normally open solenoid valve 12, the normally open bidirectional balance valve 11, respectively.

[0047] Dual failure mode: When both mechanical and electronic failures occur simultaneously.

[0048] First dual failure mode: When the second brake master cylinder 4 experiences a mechanical failure and the system loses power, all solenoid valves remain in their initial open / closed state, and the workflow is the same as in the electronic failure mode. When the driver depresses the brake pedal 1, the pedal 1 drives the first piston 31 to move. After eliminating the decoupling gap between the first piston 31 and the second piston 32, the first piston 31 and the second piston 32 directly contact each other, pushing the second piston 32 to move. Before the first piston 31 contacts the second piston 32, the high-pressure brake fluid in the first hydraulic oil chamber 33 of the first brake master cylinder is directly injected into the wheel cylinder 16 through the normally open first normally open solenoid valve 13 and the normally open bidirectional balance valve 11. After the first piston 31 contacts the second piston 32, the first piston 31 pushes the second piston 32 to build up pressure. The high-pressure brake fluid in the first hydraulic oil chamber 33 and the third hydraulic oil chamber 35 of the first brake master cylinder is input into the wheel cylinder 16 through the normally open first normally open solenoid valve 13, the normally open bidirectional balance valve 11 and the normally open second normally open solenoid valve 12, the normally open bidirectional balance valve 11, respectively.

[0049] Second double failure mode: When the first brake cylinder 3 experiences a mechanical failure and the system loses power, all solenoid valves remain in their initial open / closed state. When the driver presses the brake pedal, the pedal 1 drives the first piston 31 to move, directly injecting high-pressure brake oil from the first hydraulic oil chamber 33 of the first brake master cylinder into the wheel cylinder 16 through the normally open first normally open solenoid valve 13 and the normally open bidirectional balance valve 11 for braking.

[0050] The third double failure mode: When both the first master cylinder 3 and the second master cylinder 4 experience mechanical failure and the system loses power, all solenoid valves remain in their initial open / closed state, and the workflow is the same as the second double failure mode. When the driver depresses the brake pedal, pedal 1 drives the first piston 31 to move, directly injecting high-pressure brake fluid from the first hydraulic oil chamber 3 of the first master cylinder through the normally open first normally open solenoid valve 13 and the normally open bidirectional balance valve 11 into the wheel cylinders 16 for braking.

[0051] The beneficial effects of the technical solution of the present invention based on the above embodiments are as follows:

[0052] This invention, through the design of dual brake master cylinders and normally open and normally closed solenoid valves, enables the redundant backup function of the braking system, allowing braking to be achieved under different fault modes, ensuring the normal operation of the braking system in the event of a fault.

[0053] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0054] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A redundant electro-hydraulic braking system, characterized in that, The redundant electro-hydraulic braking system includes a first master cylinder, a second master cylinder, a first normally open solenoid valve, a second normally open solenoid valve, a first normally closed solenoid valve, a second normally closed solenoid valve, a third normally closed solenoid valve, and a normally open bidirectional balance valve. The vehicle's pedal is connected to the piston rod of the first piston of the first brake master cylinder, and the vehicle's displacement sensor is mounted on the piston rod of the first piston of the first brake master cylinder. The first hydraulic chamber of the first brake master cylinder is connected to the brake fluid input terminal of the first wheel cylinder group of the vehicle through the first normally open solenoid valve; the second hydraulic chamber of the first brake master cylinder is connected to the oil supply system through the first normally closed solenoid valve; and the third hydraulic chamber of the first brake master cylinder is connected to the brake fluid input terminal of the first wheel cylinder group of the vehicle through the second normally open solenoid valve. The first hydraulic oil chamber of the second brake master cylinder is connected to the oil supply system through a second normally closed solenoid valve; the second hydraulic oil chamber of the second brake master cylinder is connected to the brake oil input end of the second wheel cylinder group through the third normally closed solenoid valve. The brake fluid input terminals of the first wheel cylinder group and the second wheel cylinder group are connected via the normally open bidirectional balance valve. The control terminals of the first normally open solenoid valve, the second normally open solenoid valve, the first normally closed solenoid valve, the second normally closed solenoid valve, the third normally closed solenoid valve, and the normally open bidirectional balance valve are all connected to the vehicle's ECU.

2. The redundant electro-hydraulic braking system according to claim 1, characterized in that, The first brake master cylinder includes a first hydraulic cylinder, and a first piston and a second piston located inside the first hydraulic cylinder; A baffle is provided inside the first hydraulic cylinder; The first piston is located on one side of the partition, and a first hydraulic oil chamber of the first brake master cylinder is formed between the first piston and the partition. The piston rod of the first piston passes through one end of the first hydraulic cylinder and is connected to the pedal. The second piston is located on the other side of the partition. The piston rod of the second piston passes through the partition and extends into the first hydraulic oil chamber of the first brake master cylinder. The second piston and the partition form the second hydraulic oil chamber of the first brake master cylinder. The second piston and the other end of the first hydraulic cylinder form the third hydraulic oil chamber of the first brake master cylinder.

3. The redundant electro-hydraulic braking system according to claim 1, characterized in that, The second brake master cylinder includes a second hydraulic cylinder and a third piston located in the second hydraulic cylinder; The third piston divides the inner cavity of the second hydraulic cylinder to form the first hydraulic oil chamber of the second brake master cylinder and the second hydraulic oil chamber of the second brake master cylinder.

4. The redundant electro-hydraulic braking system according to any one of claims 1-3, characterized in that, In normal braking mode, when the driver depresses the pedal, the vehicle's displacement sensor transmits the pedal displacement signal to the vehicle's ECU. The ECU then controls the first normally open solenoid valve and the normally open bidirectional balance valve to close, and controls the first normally closed solenoid valve, the second normally closed solenoid valve, the third normally closed solenoid valve, and the second normally open solenoid valve to open. Hydraulic oil in the fuel delivery system enters the second hydraulic chamber of the first brake master cylinder through the first normally closed solenoid valve, pushing the second piston of the first brake master cylinder to move. This causes the brake oil in the third hydraulic chamber of the first brake master cylinder to be injected into the first wheel cylinder assembly for braking through the second normally open solenoid valve. Hydraulic oil in the fuel delivery system enters the first hydraulic chamber of the second brake master cylinder through the second normally closed solenoid valve, pushing the third piston of the second brake master cylinder to move. This causes the brake oil in the second hydraulic chamber of the second brake master cylinder to be injected into the second wheel cylinder assembly for braking through the third normally closed solenoid valve.

5. The redundant electro-hydraulic braking system according to any one of claims 1-3, characterized in that, When the first brake master cylinder fails, when the driver presses the pedal, the vehicle's displacement sensor transmits the pedal displacement signal to the vehicle's ECU. The vehicle's ECU controls the first normally open solenoid valve, the second normally open solenoid valve, and the first normally closed solenoid valve to close, and controls the second normally closed solenoid valve, the third normally closed solenoid valve, and the normally open bidirectional balance valve to open. Hydraulic oil in the oil supply system enters the first hydraulic oil chamber of the second brake master cylinder through the second normally closed solenoid valve, pushing the third piston of the second brake master cylinder to move. This causes the brake oil in the second hydraulic oil chamber of the second brake master cylinder to be injected into the second wheel cylinder group for braking through the third normally closed solenoid valve, and into the first wheel cylinder group for braking through the third normally closed solenoid valve and the normally open bidirectional balance valve.

6. The redundant electro-hydraulic braking system according to any one of claims 1-3, characterized in that, When the second brake master cylinder fails, when the driver presses the pedal, the vehicle displacement sensor transmits the pedal displacement signal to the vehicle's ECU. The vehicle's ECU controls the first normally open solenoid valve, the second normally closed solenoid valve, and the third normally closed solenoid valve to close, and controls the first normally closed solenoid valve, the second normally open solenoid valve, and the normally open bidirectional balance valve to open. Hydraulic oil in the oil supply system enters the second hydraulic oil chamber of the first brake master cylinder through the first normally closed solenoid valve, pushing the second piston of the first brake master cylinder to move. This causes the brake oil in the third hydraulic oil chamber of the first brake master cylinder to enter the first wheel cylinder group for braking through the second normally open solenoid valve, and then enters the second wheel cylinder group for braking through the second normally open solenoid valve and the normally open bidirectional balance valve.

7. The redundant electro-hydraulic braking system according to any one of claims 1-3, characterized in that, When in electronic failure mode or first dual failure mode, the driver depresses the brake pedal. The pedal moves the first piston of the first brake master cylinder, which directly contacts and pushes the second piston of the first brake master cylinder. Before the first piston contacts the second piston, brake fluid in the first hydraulic chamber of the first brake master cylinder is directly injected into the first wheel cylinder group through the first normally open solenoid valve for braking, and into the second wheel cylinder group through the first normally open solenoid valve and the normally open bidirectional balance valve for braking. After the first piston contacts the second piston, the first piston pushes the second piston to build up pressure, pushing the brake fluid in the third hydraulic chamber of the first brake master cylinder... The brake fluid is injected into the first wheel cylinder group through the second normally open solenoid valve, and the brake fluid in the first hydraulic chamber of the first brake master cylinder is injected into the first wheel cylinder group through the first normally open solenoid valve to brake the first wheel cylinder group. The brake fluid in the third hydraulic chamber of the first brake master cylinder is injected into the second wheel cylinder group through the second normally open solenoid valve and the normally open bidirectional balance valve, and the brake fluid in the first hydraulic chamber of the first brake master cylinder is injected into the second wheel cylinder group through the first normally open solenoid valve and the normally open bidirectional balance valve to brake the second wheel cylinder group. The first dual failure mode is a dual failure mode of electronic failure and second brake master cylinder failure.

8. The redundant electro-hydraulic braking system according to any one of claims 1-3, characterized in that, The oil delivery system includes a hydraulic pump, a motor, an accumulator, and a hydraulic cylinder; The hydraulic oil input end of the hydraulic pump is connected to the oil cylinder, the output shaft of the motor is connected to the shaft of the hydraulic pump, and the hydraulic oil output end of the hydraulic pump is connected to the accumulator. The hydraulic oil output end of the hydraulic pump is connected to the second hydraulic oil chamber of the first brake master cylinder through a first normally closed solenoid valve, and the hydraulic oil output end of the hydraulic pump is also connected to the first hydraulic oil chamber of the second brake master cylinder through a second normally closed solenoid valve.

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