CN113085812B

CN113085812B - Electronic hydraulic braking system and vehicle

Info

Publication number: CN113085812B
Application number: CN201911338221.9A
Authority: CN
Inventors: 贺欣; 朱晓军; 程佳; 郭海
Original assignee: BYD Co Ltd
Current assignee: BYD Co Ltd
Priority date: 2019-12-23
Filing date: 2019-12-23
Publication date: 2022-10-18
Anticipated expiration: 2039-12-23
Also published as: CN113085812A

Abstract

The application discloses electronic hydraulic braking system and vehicle. The electronic hydraulic brake system comprises an active brake cylinder and a brake wheel cylinder, wherein the active brake cylinder comprises a driving part, a two-way hydraulic cylinder and a switching valve, the two-way hydraulic cylinder comprises a first main cavity chamber, a second main cavity chamber and a piston rod for separating the first main cavity chamber from the second main cavity chamber, the driving part is used for driving the piston rod to reciprocate along a first direction and a second direction opposite to the first direction, when the driving part drives the piston rod to move along the first direction, the first main cavity chamber builds pressure, and the switching valve is communicated with the first main cavity chamber and the brake wheel cylinder; when the driving piece drives the piston rod to move along the second direction, the pressure of the second main chamber is built, and the switching valve is communicated with the second main chamber and the brake wheel cylinder. The electronic hydraulic brake system provided by the application realizes uninterrupted continuous pressure build and improves the working efficiency of the anti-lock system.

Description

Electronic hydraulic brake system and vehicle

Technical Field

The application relates to the technical field of electronic braking systems, in particular to an electronic hydraulic braking system and a vehicle.

Background

An electro-hydraulic brake (EHB) is one of brake-by-wire, determines a driver's intention to brake by calculating a displacement and a speed of a brake pedal at each braking during braking, and controls a braking force of a hydraulic system by adjusting a hydraulic brake cylinder.

In the conventional technology, the hydraulic brake cylinder can only build pressure in a single direction, for example, the pressure is built through gear and rack transmission, but when an anti-lock brake system (ABS) operates, the stroke of one-time single-direction pressure building cannot meet the requirement of the pressure of the ABS, and at this time, the electronic hydraulic system needs to maintain pressure first, and the pressure can be built continuously after the piston is pumped back to the initial position and the fluid is replenished. The process that the piston is pumped back to the initial position for fluid infusion increases the braking time of the electronic hydraulic system and reduces the working efficiency of the anti-lock braking system.

Disclosure of Invention

The application provides an electronic hydraulic braking system, electronic hydraulic braking system is through setting up two-way pneumatic cylinder, and piston rod reciprocating motion under the effect of driving piece among the two-way pneumatic cylinder, and the piston rod is being reciprocating motion's in-process, and two-way pneumatic cylinder tow-way output brake pressure has realized uninterrupted continuous pressure build, has improved anti-lock system's work efficiency.

In a first aspect, the present application provides an electro-hydraulic brake system. An active brake cylinder and a brake wheel cylinder of the electronic hydraulic brake system;

the active brake cylinder comprises a driving part, a two-way hydraulic cylinder and a switching valve, the two-way hydraulic cylinder comprises a first main chamber, a second main chamber and a piston rod for separating the first main chamber from the second main chamber, the driving part is used for driving the piston rod to reciprocate along a first direction and a second direction opposite to the first direction, one end of the switching valve is connected with the brake wheel cylinder, and the other end of the switching valve is connected with the first main chamber and the second main chamber;

when the driving piece drives the piston rod to move along a first direction, the first main chamber is pressurized, and the switching valve is communicated with the first main chamber and the brake wheel cylinder; when the driving piece drives the piston rod to move along the second direction, the pressure of the second main cavity is built, and the switching valve is communicated with the second main cavity and the brake wheel cylinder.

In one embodiment, the electronic hydraulic brake system further includes a brake pedal, a pedal displacement sensor and a controller, the brake pedal is configured to receive pedal force of a driver, the pedal displacement sensor is configured to detect displacement information of the brake pedal, the controller is coupled to the pedal displacement sensor and the driving member, and the controller controls the driving member to drive the piston rod to move according to the displacement information of the pedal displacement sensor.

In one embodiment, the electrohydraulic brake system further comprises a medium reservoir for supplying brake medium to the backup brake cylinder, a backup brake cylinder connected to the medium reservoir and the brake pedal, and a foot feel simulator connected to the backup brake cylinder, wherein the foot feel simulator provides a reaction force to the driver opposite to the pedal force as a function of the brake pedal receiving the pedal force of the driver.

In one embodiment, the electronic hydraulic brake system further includes a backup valve for communicating the backup brake cylinder with the wheel cylinder, the backup brake cylinder communicating with the wheel cylinder when the active brake cylinder is disconnected from the wheel cylinder.

In one embodiment, the electronic hydraulic brake system further includes an active valve connected between the switching valve and the brake wheel cylinder, and the active valve and the backup valve are respectively connected to the brake wheel cylinder.

In one embodiment, the electrohydraulic brake system includes a first brake circuit that communicates with the active brake cylinder via a first active valve, and a second brake circuit connected in parallel with the first brake circuit that communicates with the active brake cylinder via the second active valve.

In one specific embodiment, the first brake circuit communicates with the backup brake cylinder via a first backup valve, and the second brake circuit communicates with the backup brake cylinder via the second backup valve.

In one specific embodiment, the backup brake cylinder comprises a first backup chamber and a second backup chamber spaced apart from the first backup chamber, the first backup chamber and the second backup chamber each being connected to the medium reservoir and the first backup chamber being in communication with the first brake circuit via the first backup valve, and the second backup chamber being in communication with the second brake circuit via the second backup valve.

In one embodiment, the backup brake cylinder further includes a first piston, a second piston, a first spring, and a second spring, the first piston and the first spring are accommodated in the first backup chamber, the second piston and the second spring are accommodated in the second master chamber, the first spring, the first piston, the second spring, and the second piston are sequentially connected, the second piston is connected to the brake pedal, and a pedal force generated by the brake pedal is transmitted to the second piston.

In one embodiment, the first brake circuit and the second brake circuit are respectively provided with a pressure increasing valve for controlling a pressurized medium discharged to the brake wheel cylinder and a pressure reducing valve connected in parallel to the pressure increasing valve for controlling a pressurized medium discharged to the brake wheel cylinder.

In one embodiment, the switching valve is a high-low pressure switching valve that communicates with the first main chamber when the pressure in the first main chamber is greater than the pressure in the second main chamber.

In one embodiment, the switching valve is a two-position three-way solenoid valve, and when the switching valve is powered on, the switching valve is communicated with the second main chamber; when the switching valve is de-energized, the switching valve communicates with the first main chamber.

In a second aspect, the present application provides a vehicle. The vehicle comprises a housing and an electro-hydraulic brake system as described above mounted to the housing.

In the embodiment of the application, a piston rod in the bidirectional hydraulic cylinder reciprocates under the action of the driving piece, and in the process of reciprocating the piston rod, the bidirectional hydraulic cylinder can transmit hydraulic pressure to the active brake cylinder, so that uninterrupted continuous pressure build is realized, namely the bidirectional hydraulic cylinder outputs brake pressure in the positive and negative directions, the active brake cylinder is prevented from transmitting pressure discontinuously, the brake time of an electronic hydraulic system is prolonged, and the working efficiency of an anti-lock system is improved.

Drawings

In order to more clearly illustrate the technical solutions of the present application, the drawings required to be used in the embodiments will be briefly described below, and obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative efforts.

FIG. 1 is a schematic structural diagram of a vehicle provided by an embodiment of the present application;

FIG. 2 is a schematic illustration of the electro-hydraulic brake system of FIG. 1 in a first state;

FIG. 3 is a schematic illustration of the electro-hydraulic brake system of FIG. 2 in a second condition;

FIG. 4 is a schematic structural view of the electro-hydraulic brake system shown in FIG. 1 in another embodiment;

fig. 5 is a schematic structural view of the electro-hydraulic brake system shown in fig. 2 in a third state.

Detailed Description

Technical solutions in embodiments of the present application will be described below with reference to the drawings in the embodiments of the present application, and it is apparent that the described embodiments are only some embodiments of the present application, and not all embodiments. The embodiments and features of the embodiments of the present application may be combined with each other without conflict. All other embodiments obtained by a person of ordinary skill in the art without any inventive work based on the embodiments in the present application are within the scope of protection of the present application.

Referring to fig. 1, fig. 1 is a schematic structural diagram of a vehicle according to an embodiment of the present disclosure. The embodiment of the present application provides a vehicle 100. The vehicle 100 includes a housing 101 and an electro-hydraulic brake system 102. The electro-hydraulic brake system 102 is mounted to the housing 101. The vehicle 100 is a wheeled vehicle 100 driven or towed by a power unit, driven on a road, and used for a person or for transporting an article. As shown in fig. 1, the vehicle 100 further includes wheels 103. In the embodiment of the present application, the vehicle 100 is described as an example of an electric vehicle.

Further, referring to fig. 2 and 3, fig. 2 is a schematic structural diagram of the electronic hydraulic brake system 102 shown in fig. 1 in a first state; fig. 3 is a schematic diagram of the electro-hydraulic brake system 102 of fig. 2 in a second state. The electro-hydraulic brake system 102 includes a medium reservoir 21, an active brake cylinder 22, and a brake cylinder 23. The medium reservoir 21 serves to supply the active brake cylinder 22 with brake medium. Wherein, the brake medium is hydraulic oil. Hydraulic oil is the medium in the electro-hydraulic brake system 102 that transfers energy. The brake medium may be one of mineral oil, emulsion or synthetic hydraulic oil. The active brake cylinder 22 is coupled to a brake cylinder 23, and the brake pressure established by the active brake cylinder 22 is transmitted to the brake cylinder 23. The active brake cylinder 22 is capable of generating a hydraulic pressure that pressurizes the brake medium by mechanical power. The brake wheel cylinders 23 receive the hydraulic pressure supplied from the master cylinder 22, and then perform braking of the respective wheels.

The electro-hydraulic brake system 102 also includes a brake pedal 24, a pedal displacement sensor 25, and a controller (not shown). The brake pedal 24 is for receiving a pedal force of the driver. The pedal displacement sensor 25 is used to detect displacement information of the brake pedal 24. The controller is coupled to the pedal displacement sensor 25 and the active brake cylinder 22. The controller controls the active brake cylinder 22 based on displacement information from the pedal displacement sensor 25.

It is understood that when the driver steps on the brake pedal 24, the pedal force applied to the brake pedal 24 changes the displacement of the brake pedal 24, and the pedal displacement sensor 25 can detect this displacement information, so as to receive the braking intention of the driver as an electric signal. The controller can determine the hydraulic pressure that needs to be generated by the active brake cylinder 22 based on this displacement information.

The master brake cylinder 22 includes an actuator 221, a bidirectional hydraulic cylinder 222, and a switching valve 223. The bi-directional hydraulic cylinder 222 includes a first main chamber 201, a second main chamber 202, and a piston rod 203 separating the first main chamber 201 and the second main chamber 202. The driver 221 is configured to drive the piston rod 203 to reciprocate in a first direction and a second direction opposite to the first direction. The driver 221 can drive the piston rod 203 to reciprocate in the left-right direction. In the present embodiment, the piston rod 203 reciprocates in a straight line. In other embodiments, the piston rod 203 can also reciprocate in an arc like a pendulum.

It will be appreciated that the size of the first and second

primary chambers

201, 202 varies with the movement of the piston rod 203. In one embodiment, the drive 221 comprises a motor. The motor drives the piston rod 203 to reciprocate by forward rotation and reverse rotation. For example, when the motor rotates in the forward direction, the motor-driven piston rod 203 moves relatively away from the motor (leftward in the drawing), and when the motor rotates in the reverse direction, the motor-driven piston rod 203 moves relatively closer to the motor (rightward in the drawing).

As shown in fig. 2, when the piston rod 203 moves in the left direction by the driver 221, the first main chamber 201 becomes smaller and the second main chamber 202 becomes larger, and the first main chamber 201 is larger than the second main chamber 202. As shown in fig. 3, when the piston rod 203 moves to the right under the driving of the driver 221, the second main chamber 202 becomes smaller and the first main chamber 201 becomes larger, and at this time, the second main chamber 202 is larger than the first main chamber 201.

One end of the switching valve 223 is connected to the brake wheel cylinder 23, and the other end is connected to the first main chamber 201 and the second main chamber 202. It is understood that the switching valve 223 communicates the brake wheel cylinder 23 with the first main chamber 201 in one case, and the switching valve 223 communicates the brake wheel cylinder 23 with the second main chamber 202 in the other case.

In one embodiment, the switching valve 223 is a high and low pressure switching valve. As shown in fig. 2, switching valve 223 communicates with first main chamber 201 when the pressure in first main chamber 201 is greater than the pressure in second main chamber 202. As shown in fig. 3, switching valve 223 communicates with second main chamber 202 when the pressure in second main chamber 202 is greater than the pressure in first main chamber 201.

When the driving member 221 drives the piston rod 203 to move in the first direction, the first main chamber 201 builds pressure, and the switching valve 223 communicates the first main chamber 201 with the brake wheel cylinder 23. When the driver 221 drives the piston rod 203 to move in the second direction, the second main chamber 202 is pressurized, and the switching valve 223 communicates the second main chamber 202 with the brake wheel cylinder 23. It will be appreciated that when the driver 221 drives the piston rod 203 to move in the first direction, the pressure of the first main chamber 201 is greater than the pressure of the second main chamber 202, and the hydraulic pressure of the first main chamber 201 is transmitted to the brake wheel cylinders 23. When the driver 221 drives the piston rod 203 to move in the second direction, the pressure of the second main chamber 202 is greater than the pressure of the first main chamber 201, and the hydraulic pressure of the second main chamber 202 is transmitted to the brake wheel cylinders 23. That is, the bi-directional hydraulic cylinder 222 is capable of transmitting hydraulic pressure to the master brake cylinder 22 regardless of whether the piston rod 203 is extended or retracted relative to the driver 221.

In another embodiment, with continued reference to fig. 4, fig. 4 is a schematic diagram of the electro-hydraulic brake system 102 of fig. 1 in another embodiment. The switching valve 223 is a two-position three-way solenoid valve. The two-position three-way electromagnetic valve is controlled by double coils, one coil is powered on instantly and then the power supply is closed, and the valve is opened, and the other coil is powered on instantly and then the power supply is closed and the valve is closed. When the switching valve 223 is energized, the switching valve 223 communicates with the second main chamber 202. When the switching valve 223 is de-energized, the switching valve 223 communicates with the first main chamber 201. It will be appreciated that the switching valve 223 is not powered to the initial state, that is, the switching valve 223 communicates the first master chamber 201 with the master brake cylinder 22 to the initial state.

The controller can control whether the two-position three-way electromagnetic valve is electrified or not according to the pressure building direction of the piston rod 203. When the first main chamber 201 is pressurized, the controller controls the three-dimensional solenoid valves to be de-energized to enable the hydraulic pressure of the first main chamber 201 to be transmitted to the active brake cylinder 22. When the second master chamber 202 is pressurized, the controller controls the three-dimensional solenoid valves to be energized to enable hydraulic pressure from the second master chamber 202 to be transmitted to the active brake cylinder 22.

In this embodiment, the switching valve 223 is a two-position three-way solenoid valve structure, as shown in fig. 4, when the two-position three-way solenoid valve is in an initial non-power-on state, the first main chamber 201 is communicated with the first active valve 281 and the second active valve 282, respectively; when the two-position three-way solenoid valve is in the power-on state, the two-position three-way solenoid valve changes its position, disconnecting the first main chamber 201 from the first active valve 281 and the second active valve 282, and enabling the second main chamber 202 to communicate with the first active valve 281 and the second active valve 282. The controller can control whether the two-position three-way electromagnetic valve is electrified or not according to the pressure building direction of the piston rod 203, and can also realize uninterrupted continuous pressure building of the two-way hydraulic cylinder 222, so that the braking time of the electronic hydraulic system is prolonged, and the working efficiency of the anti-lock system is improved.

In the embodiment of the present application, the piston rod 203 in the bidirectional hydraulic cylinder 222 reciprocates under the action of the driving member 221, and during the reciprocating motion of the piston rod 203, the bidirectional hydraulic cylinder 222 can transmit hydraulic pressure to the active brake cylinder 22, so as to realize uninterrupted continuous pressure build, that is, the bidirectional hydraulic cylinder 222 outputs braking pressure in both forward and reverse directions, thereby avoiding the intermittent pressure transmission of the active brake cylinder 22, increasing the braking time of the electronic hydraulic system, and improving the working efficiency of the anti-lock braking system. In addition, in the embodiment of the present application, switching of the high-low pressure oil passages can be realized by using a high-low pressure switching valve with a simple structure, and the structure of the electronic hydraulic brake system 102 is simplified.

In one embodiment, active brake cylinder 22 further includes a current sensor 224, a transition sensor 225, and a temperature sensor 226. The current sensor 224, the switching sensor 225 and the temperature sensor 226 are coupled to the motor and the controller of the driving member 221, respectively. The current sensor 224 is used to detect the control current of the motor. The switching sensor 225 is used to detect the position of the motor rotor. The temperature sensor 226 is used to detect the temperature of the motor armature.

In the embodiment of the present application, the driver 221 and the controller are respectively coupled to the current sensor 224, the conversion sensor 225 and the temperature sensor 226, so that the driver 221 can drive the piston rod 203 to move more accurately, and the electronic hydraulic brake cylinder can finely adjust the braking force of the vehicle 100.

With continued reference to fig. 2 and 3, the electro-hydraulic brake system 102 further includes the foot feel simulator 26. The foot feel simulator 26 receives the pedal force of the driver from the brake pedal 24, and provides the driver with a reaction force against the pedal force. That is, the foot feel simulator 26 provides a reaction force corresponding to the pedal force applied to the brake pedal 24 by the driver, thereby providing the driver with a stepping feel.

In the exemplary embodiment, the foot feel simulator 26 provides the driver of the vehicle 100 with the usual feel of the brake pedal 24 when the active brake cylinder 22 is operating, so that a fine actuation of the brake pedal 24 is possible, and thus the braking force of the vehicle 100 can also be finely adjusted.

In one embodiment, electro-hydraulic brake system 102 further includes a backup brake cylinder 27 and a foot feel simulator control valve 261. The backup brake cylinder 27 is connected to the medium reservoir 21 and the brake pedal 24. The foot-feel simulator 26 is connected to a backup brake cylinder 27. The foot feel simulator 26 is connected to the backup brake cylinder 27 so that the foot feel simulator 26 can receive the hydraulic pressure discharged from the backup brake cylinder 27 to provide the driver with a reaction force against the pedal force of the brake pedal 24.

When the driver applies a pedal force to the brake pedal 24, the pedal displacement sensor 25 detects displacement information of the brake pedal 24 and transmits the displacement information to the controller. The controller controls the driver 221 to drive the bidirectional hydraulic cylinder 222 to generate corresponding hydraulic pressure according to the displacement information of the brake pedal 24, and at the same time, an oil passage between the backup brake cylinder 27 and the foot feel simulator 26 is opened, so that when the driver applies pedal force to the brake pedal 24, the backup brake cylinder 27 supplies hydraulic pressure to the foot feel simulator 26 through the foot feel simulator control valve 261, and thus the foot feel of the driver for stepping on the brake pedal 24 is formed.

Further, the electro-hydraulic brake system 102 also includes the active valve 28. The active valve 28 is connected between the switching valve 223 and the brake wheel cylinder 23. It is understood that when the active valve 28 and the switching valve 223 are both in the open state, the active brake cylinder 22 communicates with the brake wheel cylinder 23. Wherein the active valve 28 may be set to a normally closed valve (normally closed type), normally closed, and opened when receiving an electrical signal. For example, when the electronic hydraulic brake system 102 is powered off, the active valve 28 is in a closed state, and the oil path between the active brake cylinder 22 and the brake wheel cylinder 23 is disconnected; when the electro-hydraulic brake system 102 is energized, the controller controls the active valve 28 to open, and the active brake cylinder 22 is communicated with the oil passage of the brake wheel cylinder 23.

In one embodiment, the active valve 28 includes a first active valve 281 and a second active valve 282. The electro-hydraulic brake system 102 includes a first brake circuit 101 and a second brake circuit 102 connected in parallel with the first brake circuit 101. First brake circuit 101 communicates with active brake cylinder 22 via first active valve 281. The second brake circuit 102 communicates with the master brake cylinder 22 via a second master valve 282. It is understood that first brake circuit 101 and second brake circuit 102 are two independent circuits, and that second brake circuit 102 can operate when first brake circuit 101 fails.

Each of the first brake circuit 101 and the second brake circuit 102 includes two brake cylinders 23. As shown in fig. 3, brake cylinders 23 include a first brake cylinder 231, a second brake cylinder 232, a third brake cylinder 233, and a fourth brake cylinder 234. First brake wheel cylinder 231 and second brake wheel cylinder 232 are located in first brake circuit 101. Third brake wheel cylinder 233 and fourth brake wheel cylinder 234 are located in second brake circuit 102.

In the embodiment of the present application, the electro-hydraulic brake system 102 includes the first brake circuit 101 and the second brake circuit 102, and when one of the two brake circuits fails, the other brake circuit can continue to operate, so that safety can be ensured. For example, first brake circuit 101 may be connected to right rear wheel RL and left rear wheel RR of vehicle 100, and second brake circuit 102 may be connected to left front wheel FL and right front wheel FR of vehicle 100, whereby braking of vehicle 100 may be achieved even if one of the brake circuits fails. In addition to this, first brake circuit 101 may be connected to left front wheel FL and left rear wheel RL, and first brake circuit 101 may be connected to right rear wheel RR and right front wheel FR. That is, the positions of the wheel cylinders to be controlled in the first brake circuit 101 and the second brake circuit 102 are not limited to any arrangement, and may be formed in various combinations.

Further, with reference to fig. 3, the first brake circuit 101 and the second brake circuit 102 are respectively provided with a pressure increasing valve 11 and a pressure reducing valve 12 connected in parallel with the pressure increasing valve 11. That is, the pressure increasing valve 11 and the pressure reducing valve 12 control the hydraulic pressure transmitted to the brake cylinders 23, respectively. The pressure-increasing valves 11 are used to control the pressurized medium discharged to the brake cylinders 23. The pressure reducing valve 12 is used to control discharge of the pressurized medium applied to the brake cylinders 23.

Each of the brake cylinders 23 is provided with a pressure increasing valve 11 and a pressure reducing valve 12. As shown in fig. 3, the pressure-increasing valves 11 and the pressure-reducing valves 12 are the same in number as the brake cylinders 23, and are each four. In one embodiment, the pressure increasing valve 11 is a normally open valve that is normally open and closed when receiving an electric signal. The pressure reducing valve 12 may be set to a normally closed type (normally closed type) that is normally closed and opens when an electrical signal is received.

In the embodiment of the present application, the pressure-increasing valve 11 and the pressure-reducing valve 12 are arranged on the brake circuit of each wheel cylinder, and the controller controls the opening and closing of the pressure-increasing valve 11 and the pressure-reducing valve 12, so that the hydraulic pressure entering the wheel cylinder can be accurately controlled, and the braking performance of each wheel cylinder in the brake wheel cylinder 23 can be improved. For example, when the brake wheel cylinder 23 requires pressure braking, the controller controls the pressure-increasing valve 11 to be opened, and the pressure-increasing medium flows into the wheel cylinder, thereby controlling the pressure increase of the wheel cylinder. When the brake wheel cylinder 23 needs to build pressure, the controller controls the pressure reducing valve 12 to be opened, and controls the pressurized medium in the brake wheel cylinder 23 to be discharged, so that the pressure of the brake wheel cylinder 23 is reduced.

Further, with continued reference to fig. 5, fig. 5 is a schematic structural diagram of the electro-hydraulic brake system 102 shown in fig. 2 in a third state. The electro-hydraulic brake system 102 also includes a backup valve 29. The backup valve 29 is used to communicate the backup brake cylinder 27 with the brake wheel cylinder 23. When the active brake cylinder 22 is disconnected from the brake cylinder 23, the backup brake cylinder 27 communicates with the brake cylinder 23.

The backup valve 29 is set to a normally open valve, which is normally open and closes when receiving an electric signal. That is, when the system enters the mechanical backup mode due to a power outage or other failure, the backup valve 29 is opened to communicate the backup brake cylinder 27 and the brake cylinder 23, and the backup brake cylinder 27 generates the brake hydraulic pressure to be transmitted to the brake cylinder 23.

In the embodiment of the present application, when the active brake cylinder 22 cannot generate brake pressure or the generated brake pressure cannot be transmitted to the wheel cylinders 23 when the system is in a power failure or other faults, the backup valve 29 is opened, and the backup brake cylinder 27 can provide brake pressure to the wheel cylinders 23, so that the electronic hydraulic brake system 102 can still operate, thereby ensuring safety.

Further, the active valve 28 and the backup valve 29 are connected to the brake cylinders 23, respectively.

In one case, when the system enters the mechanical standby mode of operation due to a power outage or other malfunction, the controller controls the standby valve 29 to open and the active valve 28 to close, and the medium flowing through the standby valve 29 flows directly into the brake cylinders 23 and does not flow into the active valve 28.

In the embodiment of the present application, when the system enters the mechanical standby operation mode due to power failure or other failures, the brake fluid pressure of the standby brake cylinder 27 directly enters the brake wheel cylinder 23 through the pressure increasing valve 11 or the pressure reducing valve 12 after passing through the standby valve 29, and does not pass through the active valve 28 and the bidirectional hydraulic cylinder 222, so that the loss of the fluid volume flowing out of the standby brake cylinder 27 from the active brake cylinder 22 is not caused, the braking performance of the standby brake cylinder 27 in the mechanical standby mode is fully exerted, the braking strength in the mechanical standby mode is improved, and the braking distance is reduced. Meanwhile, the number of the electromagnetic valves is reduced, so that the system is simplified, and the system performance is improved.

In other cases, the controller controls the active valve 28 in combination with the standby valve 29 to be energized and/or de-energized. The controller can also be implemented by controlling the active valve 28 to communicate with the flow path of the backup valve 29 by energizing and/or de-energizing the combination of the active valve 28 and the backup valve 29 to implement self-check and venting functions. For example, when the system requires self-test or system exhaust, the bi-directional hydraulic cylinder 22 is pressurized and pressure is supplied to the backup brake cylinder 27 through the active valve 28 and the backup valve 29, thereby maintaining the pressure in the backup brake cylinder 27 without requiring the driver to depress the brake pedal 24. When the vehicle 100 is manually evacuated, the drive device or the operator depresses the brake pedal 24 to pressurize the backup brake cylinder 27, and the high pressure in the backup brake cylinder 27 is supplied to the medium reservoir 21 via the backup valve 29, the active valve 28, the two-way hydraulic cylinder 22, and the air in the backup brake cylinder 27 and the two-way hydraulic cylinder 22 is removed.

In the embodiment of the present application, the description is given by taking the case where the electro-hydraulic brake system 102 includes the first brake circuit 101 and the second brake circuit 102 as an example, and accordingly, the backup valve 29 includes the first backup valve 291 and the second backup valve 292. As shown in fig. 5, first brake circuit 101 communicates with backup brake cylinder 27 via first backup valve 291, and second brake circuit 102 communicates with backup brake cylinder 27 via second backup valve 292.

In the present embodiment, the backup valve 29 includes a first backup valve 291 and a second backup valve 292, and when the system is in the mechanical backup mode, when a failure may occur in one of the two brake circuits, the other brake circuit can continue to operate, so that safety may be ensured.

With continued reference to FIG. 5, backup brake cylinder 27 includes a first backup chamber 271 and a second backup chamber 272 spaced from first backup chamber 271. The first backup chamber 271 and the second backup chamber 272 are both connected to the medium reservoir 21, and the first backup chamber 271 communicates with the first brake circuit 101 via a first backup valve 291, and the second backup chamber 272 communicates with the second brake circuit 102 via a second backup valve 292.

In the embodiment of the present application, the brake pressure generated by the first backup chamber 271 is transmitted to the first brake circuit 101 through the first backup valve 291, the brake pressure generated by the second backup chamber 272 is transmitted to the second brake circuit 102 through the second backup valve 292, when one of the first backup chamber 271 and the second backup chamber 272 fails to provide the brake hydraulic pressure, the other backup chamber can ensure the normal operation of the mechanical brake backup mode, and the failure of the chamber to provide the brake pressure when only one chamber is provided in the backup brake cylinder 27, which results in the failure of the mechanical backup mode, is avoided, thereby improving the reliability of the electronic hydraulic brake system 102. For example, one of the first and

second standby chambers

271 and 272 may be connected to the right and left rear wheels RL and RR of the vehicle 100, and the other may be connected to the left and right front wheels FL and FR, whereby braking of the vehicle 100 may be achieved even if one of the chambers malfunctions.

In one embodiment, backup brake cylinder 27 further includes a first piston 273 and a second piston 274. The first piston 273 is housed in the first backup chamber 271. The second piston 274 is received in the second backup chamber 272. Wherein the second piston 274 is connected to the brake pedal 24, and the pedal force generated by the brake pedal 24 is transmitted to the second piston 274.

In the present embodiment, the backup brake cylinder 27 includes a first backup chamber 271, a second backup chamber 272, and a first piston 273 and a second piston 274 provided in the backup chambers. A second piston 274 connected to the brake pedal 24 is provided in the second backup chamber 272, a first piston 273 is provided in the first backup chamber 271, and the first piston 273 controls the first backup chamber 271 and the second backup chamber 272 to generate hydraulic pressure in accordance with displacement of the brake pedal 24.

Further, with continued reference to fig. 5, backup brake cylinder 27 further includes a first spring 275 and a second spring 276. The first spring 275 is housed in the first backup chamber 271. The second spring 276 is received in the second backup chamber 272. The first spring 275, the first piston 273, the second spring 276 and the second piston 274 are connected in sequence, the second piston 274 is connected with the brake pedal 24, and pedal force generated by the brake pedal 24 is transmitted to the second piston 274.

It will be appreciated that in the present embodiment, a first spring 275 is disposed between the end of the first backup chamber 271 and the first piston 273, and a second spring 276 is disposed between the first piston 273 and the second piston 274. When the first spring 275 and the second spring 276 are displaced by the change in the operation of the brake pedal 24 by the driver, the first piston 273 and the second piston 274 are moved, and at this time, the first spring 275 and the second spring 276 are compressed. When the pedal force of the brake pedal 24 is released, the first spring 275 and the second spring 276 are expanded by the elastic force, and the first piston 273 and the second piston 274 can return to the original positions.

Wherein the brake pedal 24 and the second piston 274 may be arranged to be connected by an input rod. The input rod may be disposed in direct connection with the second piston 274 or in close contact without a space, so that when the driver depresses the brake pedal 24, there is no pedal lost motion interval and the backup brake cylinder 27 may be directly pressurized.

The foregoing detailed description of the embodiments of the present application has been presented to illustrate the principles and implementations of the present application, and the above description of the embodiments is only provided to help understand the methods and their core ideas of the present application; meanwhile, for a person skilled in the art, according to the idea of the present application, there may be variations in the specific embodiments and application scope, and in summary, the content of the present specification should not be construed as a limitation to the present application.

Claims

1. An electronic hydraulic brake system is characterized by comprising an active brake cylinder and a brake wheel cylinder;

the active brake cylinder comprises a driving part, a bidirectional hydraulic cylinder and a switching valve, the bidirectional hydraulic cylinder comprises a first main chamber, a second main chamber and a piston rod for separating the first main chamber from the second main chamber, the driving part is used for driving the piston rod to reciprocate along a first direction and a second direction opposite to the first direction, one end of the switching valve is connected with the brake wheel cylinder, the other end of the switching valve is connected with the first main chamber and the second main chamber, the switching valve is a high-low pressure switching valve, and when the pressure in the first main chamber is larger than the pressure in the second main chamber, the switching valve is communicated with the first main chamber;

when the driving piece drives the piston rod to move along a first direction, the first main chamber is pressurized, and the switching valve is communicated with the first main chamber and the brake wheel cylinder; when the driving piece drives the piston rod to move along a second direction, the second main chamber is pressurized, and the switching valve is communicated with the second main chamber and the brake wheel cylinder;

the electro-hydraulic brake system further includes an active valve connected between the switching valve and the brake wheel cylinder.

2. The electro-hydraulic brake system of claim 1, further comprising a brake pedal configured to receive a pedal force of a driver, a pedal displacement sensor configured to detect displacement information of the brake pedal, and a controller coupled to the pedal displacement sensor and the driving member, wherein the controller controls the driving member to drive the piston rod to move according to the displacement information of the pedal displacement sensor.

3. The electro-hydraulic brake system of claim 2, further comprising a medium reservoir for providing brake medium to the backup brake cylinder, a backup brake cylinder connected to the medium reservoir and the brake pedal, and a foot feel simulator connected to the backup brake cylinder, the foot feel simulator providing a reaction force to the driver opposite to a pedal force of the driver in response to the brake pedal receiving the pedal force.

4. The electro-hydraulic brake system of claim 3, further comprising a backup valve for communicating the backup brake cylinder with the wheel cylinders, the backup brake cylinder communicating with the wheel cylinders when the active brake cylinder is disconnected from the wheel cylinders.

5. The electro-hydraulic brake system as defined in any one of claims 3 to 4, including a first brake circuit communicating with the active brake cylinder through a first active valve, and a second brake circuit connected in parallel with the first brake circuit, the second brake circuit communicating with the active brake cylinder through a second active valve.

6. The electro-hydraulic brake system of claim 5, wherein the first brake circuit communicates with the reserve brake cylinder through a first backup valve and the second brake circuit communicates with the reserve brake cylinder through a second backup valve.

7. The electro-hydraulic brake system of claim 6, wherein the backup brake cylinder includes a first backup chamber and a second backup chamber spaced from the first backup chamber, the first backup chamber and the second backup chamber each being connected to the media reservoir, and the first backup chamber being in communication with the first brake circuit through the first backup valve and the second backup chamber being in communication with the second brake circuit through the second backup valve.

8. The electro-hydraulic brake system of claim 7, wherein the backup brake cylinder further comprises a first piston, a second piston, a first spring, and a second spring, the first piston and the first spring being received in the first backup chamber, the second piston and the second spring being received in the second backup chamber, the first spring, the first piston, the second spring, and the second piston being connected in series, and the second piston being connected to the brake pedal, a pedal force generated by the brake pedal being transmitted to the second piston.

9. The electro-hydraulic brake system according to claim 5, wherein the first brake circuit and the second brake circuit are provided with pressure-increasing valves for controlling discharge of the pressurized medium applied to the wheel cylinders, and pressure-reducing valves connected in parallel with the pressure-increasing valves for controlling discharge of the pressurized medium applied to the wheel cylinders, respectively.

10. A vehicle comprising a housing and an electro-hydraulic brake system as claimed in any one of claims 1 to 9, said electro-hydraulic brake system being mounted to said housing.