CN211617660U - Brake-by-wire system capable of simulating pedal feel - Google Patents
Brake-by-wire system capable of simulating pedal feel Download PDFInfo
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- CN211617660U CN211617660U CN202020257157.3U CN202020257157U CN211617660U CN 211617660 U CN211617660 U CN 211617660U CN 202020257157 U CN202020257157 U CN 202020257157U CN 211617660 U CN211617660 U CN 211617660U
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Abstract
The utility model relates to a can simulate the drive-by-wire braking system of footboard sensation, the concrete structure includes brake master cylinder, master cylinder drive arrangement, brake wheel cylinder, liquid storage pot, secondary master cylinder, footboard push rod, footboard sensation simulator and electrical control unit ECU, the utility model discloses braking system includes three kinds of braking functions of conventional braking, active braking and failure backup, and conventional braking includes pressure boost, pressurize and decompression three processes; the utility model realizes the decoupling of the brake pedal and the brake wheel cylinder, and can simulate various complex pedal counter forces by adjusting the pedal feel simulator of the reversing valve so as to match drivers with different driving styles; the pedal travel sensor can realize the identification of the braking intention of the driver; the linear pressure regulating valve can realize accurate control of the pressure of the brake wheel cylinder.
Description
Technical Field
The utility model relates to a drive-by-wire braking system, in particular to can simulate drive-by-wire braking system of footboard sensation.
Background
The birth and development of the automobile bring convenience to the daily trip of human beings and make the world economy more vigorous. Meanwhile, the development of the automobile industry also brings some adverse effects to the environment, traffic, trip safety, energy sources and the like, so that the safety, energy conservation and environmental protection become the subject of the current development of the automobile industry, and the active safety technology, the new energy technology and the intelligent technology of the automobile are rapidly developed. The brake system is closely related to the driving safety of the automobile and is a hot point developed by people.
The traditional braking system is mature in technology, but is limited by the structure and the working principle along with the development of automobile electromotion and intelligent technology, and the man-machine decoupling, the active rapid pressure building, the accurate control of single-wheel pressure and the like of the braking system are difficult to realize. For example, conventional vacuum assisted brake systems rely on an engine to provide a vacuum source, but electric vehicles eliminate the engine and conventional brake system technology is challenged.
The brake-by-wire system is developed by combining a brake-by-wire technology and an automobile brake system, and realizes the complete decoupling of pedal force, namely, the direct connection between a brake pedal and a brake wheel cylinder is eliminated, the brake intention of a driver is not transmitted to the brake system in a mechanical mode but in an electronic mode, and therefore a pedal feeling simulator needs to be designed to simulate the foot feeling of the driver.
A typical brake-by-wire system mainly includes an electro-hydraulic brake system (EHB) and an electro-mechanical brake system (EMB). The EHB braking system cancels a vacuum booster, adopts a high-pressure accumulator as a system pressure source, has simple and compact structure, can decouple a brake pedal and a brake wheel cylinder, can independently control the braking force of each wheel and is easy to recover energy. However, most of the pedal feel simulators are passive, pedal feel is difficult to adjust, hydraulic pipelines are complex, braking efficiency is reduced, and braking requirements are difficult to meet when a system circuit fails. The EMB braking system mostly adopts a planetary gear mechanism to reduce speed and increase torque, and converts rotation into translation through a ball screw mechanism, so that a brake caliper body clamps a brake disc to complete braking. Although the EMB braking system has the advantages of no braking pipeline, high braking efficiency and the like, the EMB braking system is high in cost, high in working environment temperature and high in reliability requirement, and light-weight design and mass production are difficult to achieve.
Disclosure of Invention
The utility model provides a drive-by-wire braking system that can simulate the pedal feel for solving the above technical problems, the concrete structure includes brake master cylinder, master cylinder drive device, brake wheel cylinder, liquid storage pot, secondary master cylinder, pedal push rod, pedal feel simulator and electric control unit ECU, wherein, the brake master cylinder include master cylinder push rod, master cylinder piston and master cylinder return spring, form the master cylinder hydraulic chamber between master cylinder piston and the cylinder body, master cylinder return spring establishes in the master cylinder hydraulic chamber; the master cylinder driving device is connected with the master cylinder push rod and can push a master cylinder piston to be pressurized in a master cylinder hydraulic cavity; the master cylinder hydraulic cavity is connected with a brake wheel cylinder through a pipeline, and the brake wheel cylinder is connected with the liquid storage tank through a pipeline; a first piston and a second piston are sequentially assembled in the secondary main cylinder, a first hydraulic cavity and a second hydraulic cavity are sequentially formed among the first piston, the second piston and the bottom of the cylinder body, return springs are arranged in the first hydraulic cavity and the second hydraulic cavity, the brake pedal is connected with the pedal push rod, the pedal push rod penetrates through the front end of the secondary main cylinder to be connected with the first piston, the first hydraulic cavity of the secondary main cylinder is connected with the pedal feeling simulator through a pipeline, the second hydraulic cavity of the secondary main cylinder is connected with the liquid storage tank through a pipeline provided with a normally closed electromagnetic valve respectively, and is connected with a liquid inlet of the brake wheel cylinder through a pipeline provided with a normally open electromagnetic valve; and the electronic control unit ECU is respectively connected with the normally closed electromagnetic valve and the normally open electromagnetic valve, and the switch is controlled by the electronic control unit ECU.
A pressure increasing valve is arranged on a pipeline between the master cylinder hydraulic cavity and the brake wheel cylinder, and a pressure reducing valve is arranged on a pipeline between the brake wheel cylinder and the liquid storage tank; the pressure increasing valve is a normally open type electromagnetic valve, and the pressure reducing valve is a normally closed type electromagnetic valve; the pressure increasing valve and the pressure reducing valve are respectively connected with the electronic control unit ECU, and the switch is controlled by the electronic control unit ECU.
The utility model also comprises a hydraulic pressure sensor and a pedal travel sensor, wherein the hydraulic pressure sensor is connected with the liquid outlet of the main cylinder hydraulic cavity and the pressure increasing valve of each brake wheel cylinder to measure the hydraulic pressure of the liquid outlet of the main cylinder hydraulic cavity and the hydraulic pressure of each brake wheel cylinder; the pedal stroke sensor is arranged on the pedal push rod and used for detecting displacement data of the pedal push rod; the hydraulic pressure sensor and the pedal travel sensor are respectively connected with the electronic control unit ECU and transmit data to the electronic control unit ECU in real time.
The pedal feel simulator is internally divided into a hydraulic cavity and a spring cavity by a simulator piston, and the first hydraulic cavity of the secondary master cylinder is connected with the hydraulic cavity of the pedal feel simulator through a pipeline; a simulator return spring and a simulator rubber spring are arranged in the spring cavity, the simulator return spring is connected between the simulator piston and the bottom of the simulator cylinder body, the simulator rubber spring is located on the inner side of the simulator return spring, and one end of the simulator rubber spring is fixed on the simulator piston.
A one-way valve is arranged on a pipeline between the first hydraulic cavity of the secondary master cylinder and the pedal feel simulator, and when the first piston of the secondary master cylinder is reset, brake fluid in the hydraulic cavity of the pedal feel simulator flows through the one-way valve and returns to the first hydraulic cavity of the secondary master cylinder; a reversing valve is connected in parallel with the one-way valve, the reversing valve is a two-position five-way electromagnetic valve, the liquid inlet is connected with the first hydraulic cavity of the secondary main cylinder through a pipeline, the reversing valve is in a left position when the power is off, so that the liquid outlet in the left position is in a normally open state, the hydraulic cavity of the pedal feeling simulator is connected, the reversing valve is in a right position when the power is on, so that the liquid outlet in the right position is in a normally closed state and is connected with the liquid storage tank; the reversing valve is connected with the electronic control unit ECU through a line, and the electronic control unit ECU controls reversing.
The liquid storage tank is respectively connected with liquid inlets of a main cylinder hydraulic cavity of the brake main cylinder and a first hydraulic cavity and a second hydraulic cavity of the secondary main cylinder through pipelines, and brake liquid is supplemented into the main cylinder hydraulic cavity, the first hydraulic cavity and the second hydraulic cavity.
The main cylinder driving device comprises a rotating motor, a pinion, a bull gear, a crank, a connecting rod and a sliding block, wherein an output shaft of the rotating motor and the pinion are coaxially arranged, the bull gear is meshed with the pinion to form a first-stage speed reduction and torque increase mechanism, one end of the crank is fixed at the center of the bull gear and is arranged along the radial direction of the bull gear, the other end of the crank is hinged with the connecting rod, the other end of the connecting rod is hinged with the sliding block, the sliding block is connected with a main cylinder push rod of the brake main cylinder; the rotating motor is connected with the electronic control unit ECU, and the electronic control unit ECU sends a control signal to control the rotation of the rotating motor.
And a linear pressure regulating valve is also arranged on a pipeline between the pressure reducing valve of the brake wheel cylinder and the liquid storage tank, is a normally open electromagnetic valve with adjustable duty ratio, is connected with the electronic control unit ECU through a circuit, and is controlled to regulate the opening degree through the electronic control unit ECU.
The connection modes of the electronic control unit ECU and each electromagnetic valve and each sensor are line connection.
The utility model discloses a theory of operation:
1. and (3) conventional braking:
when a driver steps on a brake pedal, the electronic control unit ECU controls the normally closed electromagnetic valve to be electrified and opened, the normally open electromagnetic valve is electrified and closed, the reversing valve is in the left position, the pedal push rod pushes the first piston of the secondary master cylinder to start to move, and then the second piston is pushed to move through the return spring.
On the other hand, the pedal stroke sensor obtains pedal displacement information and transmits the pedal displacement information to the electronic control unit ECU, the electronic control unit ECU calculates the total braking force demand after receiving signals, then the required hydraulic braking force is obtained according to the working characteristics of the main cylinder driving device, the electronic control unit ECU sends control signals to the rotating motor to drive the rotating motor to rotate, the rotating motor pushes the main cylinder piston to move through the primary speed reduction and torque increase mechanism, the crank connecting rod structure, the sliding block and the main cylinder push rod, the main cylinder piston is internally provided with pressure in the main cylinder hydraulic cavity, and the braking fluid in the main cylinder hydraulic cavity transmits braking force to each brake wheel cylinder through the hydraulic pipeline.
The conventional braking can be divided into three processes of pressurization, pressure maintaining and pressure reducing.
a) Pressurization process
When a driver steps on a brake pedal, the normally closed electromagnetic valve is opened, the normally open electromagnetic valve is closed, and the reversing valve is in the left position; four pressure increasing valves respectively connected with the brake cylinder are powered off and opened, four pressure reducing valves are powered off and closed, and brake fluid enters the brake cylinder from a main cylinder hydraulic cavity of the brake main cylinder to build pressure.
b) Pressure maintaining process
When the electronic control unit ECU decides that the pressure of the brake system needs to be maintained, the four pressure increasing valves are all powered on and closed, the four pressure reducing valves are all powered off and closed, at the moment, the brake fluid in the brake wheel cylinder and the brake pipeline are all in an isolated state, and the brake pressure in the brake wheel cylinder is kept unchanged.
c) Pressure reduction process
When a driver releases a brake pedal or a control strategy decides that the pressure of the brake wheel cylinder needs to be reduced, the electronic control unit ECU controls the four pressure increasing valves to be electrified and closed, the four pressure reducing valves are electrified and opened, at the moment, brake fluid in the brake wheel cylinder flows back to the liquid storage tank through the pressure reducing valve pipeline, and the pressure reduction process of the brake wheel cylinder is completed after the pressure of the brake wheel cylinder is reduced.
The pedal feeling simulator simulates the process of pedal force:
in the conventional braking process, the pedal is completely decoupled, namely a driver is only responsible for giving out target braking pressure, the actual boosting process is completed by controlling a master cylinder driving device, a brake master cylinder and all electromagnetic valves by an Electronic Control Unit (ECU), and the pedal feeling simulator provides the same pedal feeling as the conventional braking system for the driver according to a pedal force and pedal displacement curve of the conventional braking system.
In the process, the normally closed electromagnetic valve is opened, the normally open electromagnetic valve is closed, the reversing valve is in the left position, when a driver steps on the brake pedal, brake fluid in the first hydraulic cavity of the secondary master cylinder flows to the hydraulic cavity of the pedal feeling simulator through the reversing valve and acts on the simulator piston to push the simulator piston to move towards the bottom of the simulator cylinder body. When the pedal displacement is small, the simulator return spring generates pedal reaction force; along with the increase of pedal displacement, the simulator piston continues to move until the simulator rubber spring contacts with the bottom of the simulator cylinder body, and then the simulator rubber spring and the simulator return spring are connected in parallel to provide pedal reaction force together.
In order to meet the requirements of different types of drivers on the feeling of the brake pedal, the steering valve can be adjusted by the ECU. When the reversing valve is switched to the right position, the first hydraulic cavity of the secondary master cylinder is communicated with the liquid storage tank, brake liquid in the first hydraulic cavity flows into the liquid storage tank through the reversing valve, the pedal feeling simulator does not provide simulated pedal force at the moment, the pedal force is provided by the return spring in the secondary master cylinder, and therefore the generated pedal counter force is reduced under the same pedal displacement. The electronic control unit ECU controls the reversing valve to switch between the left position and the right position, so that the pedal reaction force is adjusted, and drivers with different driving styles can be matched.
Control process of brake wheel cylinder pressure:
the utility model discloses an among the braking system, four pressure-increasing valves and four relief pressure valves all are the ooff valve, only open and close two kinds of states, for the control that realizes pressure, have inserted a linear air-vent valve in the common pipeline that liquid storage pot was gone into through corresponding relief pressure valve backward flow in each brake wheel cylinder. And the electronic control unit ECU receives signals of the pedal stroke sensor and the hydraulic pressure sensor, and controls the opening of the linear pressure regulating valve according to the actual needs of the system through analysis and decision, so that the accurate control of the pressure is realized.
2. Active braking:
because the utility model discloses a braking system footboard complete decoupling zero consequently can be independent of driver's pedal force execution braking operation. When an emergency situation occurs in front of an automobile, an Electronic Control Unit (ECU) of the braking system sends a control signal to a rotating motor through decision judgment, and a main cylinder driving device is used for quickly building pressure for a main brake cylinder. At the moment, four pressure increasing valves in the brake system are all powered off and opened, four pressure reducing valves are all powered off and closed, and brake fluid enters a brake wheel cylinder from a brake master cylinder to build pressure.
3. And (3) failure backup:
when an Electronic Control Unit (ECU) of the braking system fails, the normally closed electromagnetic valve is closed in a power-off mode, the normally open electromagnetic valve is opened in a power-off mode, the reversing valve is in the left position, the four pressure increasing valves are opened in a power-off mode, and the four pressure reducing valves are closed in a power-off mode. When a driver steps on a brake pedal, brake fluid in the first hydraulic cavity of the secondary master cylinder flows into the pedal feeling simulator through the reversing valve, and brake fluid in the second hydraulic cavity of the secondary master cylinder flows into the brake wheel cylinder, so that wheels obtain enough braking force, and the failure backup function is realized.
The utility model has the advantages that:
1. the utility model discloses a complete decoupling zero of brake pedal and brake wheel cylinder combines footboard sensation simulator of footboard power adjustable, can simulate the footboard power of various complicacies, through adjusting the driver that the footboard sensation matches different driving styles.
2. The utility model discloses added footboard stroke sensor and hydraulic pressure force sensor, can realize the accurate control of discerning and pressure of driver's braking intention, and then can accurate hydraulic pressure force of adjusting brake wheel cylinder.
3. The utility model discloses have the backup function of inefficacy, when outage or automatically controlled unit ECU became invalid promptly, can build the mode through the traditional machinery of secondary master cylinder and provide hydraulic braking force for the brake wheel cylinder.
4. The utility model discloses the structure accords with lightweight design demand, and it is low to require operational environment condition, and adaptability is stronger, except can realizing conventional braking function, can also integrate functions such as ABS, TCS, ESP, AEB.
Drawings
FIG. 1 is a schematic view of the overall structure of the present invention;
FIG. 2 is a schematic structural view of the brake master cylinder of the present invention;
FIG. 3 is a schematic structural view of a secondary master cylinder of the present invention;
FIG. 4 is a schematic view of the pedal feel simulator of the present invention;
FIG. 5 is a schematic structural view of the master cylinder driving device of the present invention;
1. a brake master cylinder 2, a master cylinder driving device 3, a brake wheel cylinder 4, a reservoir tank 5, a secondary master cylinder 6, a pedal push rod 7, a pedal feel simulator 8, an electronic control unit ECU 9, a master cylinder push rod 10, a master cylinder piston 11, a master cylinder return spring 12, a master cylinder hydraulic chamber 13, a pressure increasing valve 14, a pressure reducing valve 15, a first piston 16, a second piston 17, a first hydraulic chamber 18, a second hydraulic chamber 19, a brake pedal 20, a normally closed solenoid valve 21, a normally open solenoid valve 22, a hydraulic pressure sensor 23, a pedal stroke sensor 24, a simulator piston 25, a hydraulic chamber 26, a spring chamber 27, a simulator return spring 28, a simulator rubber spring 29, a check valve 30, a reversing valve 31, a rotating electrical machine 32, a pinion 33, a bull gear 34, a crank 35, a connecting rod 36, a, A slide block 37 and a linear pressure regulating valve.
Detailed Description
Please refer to fig. 1-5:
the utility model provides a can simulate drive-by-wire braking system of footboard sensation, concrete structure includes brake master cylinder 1, master cylinder drive arrangement 2, brake wheel cylinder 3, liquid storage pot 4, secondary master cylinder 5, pedal push rod 6, footboard sensation simulator 7 and electronic control unit ECU8, wherein, brake master cylinder 1 include master cylinder push rod 9, master cylinder piston 10 and master cylinder return spring 11, form master cylinder hydraulic chamber 12 between master cylinder piston 10 and the cylinder body, master cylinder return spring 11 establishes in master cylinder hydraulic chamber 12, provides the resilience for master cylinder piston 10; the main cylinder driving device 2 is connected with a main cylinder push rod 9, the main cylinder push rod 9 penetrates through the front end of the cylinder body to be connected with a main cylinder piston 10, and the main cylinder piston 10 is pushed to build pressure in a main cylinder hydraulic cavity 12; the master cylinder hydraulic cavity 12 is connected with each brake cylinder 3 through a pipeline respectively provided with a pressure increasing valve 13, and each brake cylinder 3 is connected with the liquid storage tank 4 through a pipeline respectively provided with a pressure reducing valve 14; a first piston 15 and a second piston 16 are sequentially assembled in the secondary main cylinder 5, a first hydraulic cavity 17 and a second hydraulic cavity 18 are sequentially formed between the first piston 15 and the second piston 16 and the bottom of the cylinder body, return springs are arranged in the first hydraulic cavity 17 and the second hydraulic cavity 18, a brake pedal 19 is connected with a pedal push rod 6, the pedal push rod 6 penetrates through the front end of the secondary main cylinder 5 to be connected with the first piston 15, the first hydraulic cavity 17 of the secondary main cylinder 5 is connected with a hydraulic cavity 25 of a pedal feeling simulator 7 through a pipeline, the second hydraulic cavity 18 of the secondary main cylinder 5 is respectively connected with a liquid storage tank 4 through a pipeline with a normally closed electromagnetic valve 20, and is connected with a liquid inlet of a pressure increasing valve 13 of a brake cylinder 3 through a pipeline with a normally open electromagnetic valve 21; the electronic control unit ECU8 is connected to the pressure increasing valve 13, the pressure reducing valve 14, the normally closed electromagnetic valve 20, and the normally open electromagnetic valve 21, respectively.
The pressure increasing valve 13 is a normally open type electromagnetic valve, and the pressure reducing valve 14 is a normally closed type electromagnetic valve.
The utility model also comprises a hydraulic pressure sensor 22 and a pedal travel sensor 23, wherein the hydraulic pressure sensor 22 is connected with the liquid outlet of the main cylinder hydraulic cavity 12 and the pressure increasing valve 13 of each brake wheel cylinder 3 to measure the hydraulic pressure of the liquid outlet of the main cylinder hydraulic cavity 12 and the hydraulic pressure of each brake wheel cylinder 3; the pedal stroke sensor 23 is arranged on the pedal push rod 6 and is used for detecting displacement data of the pedal push rod 6; the hydraulic pressure sensor 22 and the pedal stroke sensor 23 are respectively connected to the ECU8, and transmit data to the ECU8 in real time.
The pedal feel simulator 7 is internally divided into a hydraulic chamber 25 and a spring chamber 26 by a simulator piston 24, the spring chamber 26 is internally provided with a simulator return spring 27 and a simulator rubber spring 28, the simulator return spring 27 is connected between the simulator piston 24 and the bottom of the simulator cylinder, and the simulator rubber spring 28 is positioned inside the simulator return spring 27 and has one end fixed to the simulator piston 24.
A check valve 29 is arranged on a pipeline between the first hydraulic chamber 17 of the secondary master cylinder 5 and the pedal feel simulator 7, namely, the hydraulic chamber 25 of the pedal feel simulator 7 is communicated with the first hydraulic chamber 17 of the secondary master cylinder 5, when the first piston 15 of the secondary master cylinder 5 is reset, the brake fluid in the hydraulic chamber 25 of the pedal feel simulator 7 flows back to the first hydraulic chamber 17 of the secondary master cylinder 5 through the check valve 29; a reversing valve 30 is connected in parallel with the one-way valve 29, the reversing valve 30 is a two-position five-way electromagnetic valve, a liquid inlet is connected with the first hydraulic cavity 17 of the secondary main cylinder 5 through a pipeline, the reversing valve 30 is positioned at the left position when the power is off, so that a liquid outlet at the left position is in a normally open state and is connected with the hydraulic cavity 25 of the pedal feeling simulator 7, and the reversing valve 30 is positioned at the right position when the power is on, so that a liquid outlet at the right position is in a normally closed state and is connected with the liquid storage tank; the diverter valve 30 is connected by a line to an electronic control unit ECU8 and the diverter is controlled by an electronic control unit ECU 8.
The reservoir tank 4 is respectively connected with the liquid inlets of the master cylinder hydraulic chamber 12 of the master cylinder 1, the first hydraulic chamber 17 of the secondary master cylinder 5 and the second hydraulic chamber 18 through pipelines, and supplies brake liquid to the master cylinder hydraulic chamber 12, the first hydraulic chamber 17 and the second hydraulic chamber 18.
The master cylinder driving device 2 comprises a rotating motor 31, a pinion 32, a gearwheel 33, a crank 34, a connecting rod 35 and a sliding block 36, wherein an output shaft of the rotating motor 31 and the pinion 32 are coaxially arranged, the gearwheel 33 is meshed with the pinion 32 to form a first-stage speed reduction and torque increase mechanism, one end of the crank 34 is fixed in the center of the gearwheel 33 and radially arranged along the gearwheel 33, the other end of the crank is hinged with the connecting rod 35, the other end of the connecting rod 35 is hinged with the sliding block 36, the sliding block 36 is connected with a master cylinder push rod 9 of the brake master cylinder 1, and the sliding block 36 is arranged in; the rotating electric machine 31 is connected with the electronic control unit ECU8, and the electronic control unit ECU8 sends a control signal to control the rotation of the rotating electric machine.
A linear pressure regulating valve 37 is further arranged on a pipeline between the pressure reducing valve 14 of the brake wheel cylinder 3 and the liquid storage tank 4, the linear pressure regulating valve 37 is a normally open type electromagnetic valve with adjustable duty ratio, and is connected with an electronic control unit ECU8 through a line, and the opening degree is controlled and regulated through an electronic control unit ECU 8.
The connection mode of the electronic control unit ECU8 and each electromagnetic valve and each sensor is line connection.
The utility model discloses a theory of operation:
1. and (3) conventional braking:
when a driver steps on the brake pedal 19, the electronic control unit ECU8 controls the normally closed solenoid valve 20 to be powered on and opened, the normally open solenoid valve 21 to be powered on and closed, the reversing valve 30 is in the left position and communicated with the pedal feel simulator 7, the pedal push rod 6 pushes the first piston 15 of the secondary master cylinder 5 to start moving, and then pushes the second piston 16 to move through the return spring, as the normally closed solenoid valve 20 is opened and the normally open solenoid valve 21 is closed, the brake fluid flowing out of the second hydraulic chamber 18 of the secondary master cylinder 5 flows back to the liquid storage tank 4 through the normally closed solenoid valve 20, the brake fluid in the first hydraulic chamber 17 of the secondary master cylinder 5 flows into the pedal feel simulator 7 through the reversing valve 30, and at the moment, no pressure is built in the.
On the other hand, the pedal stroke sensor 23 obtains pedal displacement information and transmits the pedal displacement information to the electronic control unit ECU8, the electronic control unit ECU8 calculates a total braking force demand after receiving signals, then obtains a required hydraulic braking force according to the working characteristics of the master cylinder driving device 2, the electronic control unit ECU8 sends a control signal to the rotating motor 31 to drive the rotating motor 31 to rotate, the rotating motor 31 pushes the master cylinder piston 10 to move through the primary speed reduction and torque increase mechanism, the crank connecting rod structure, the slider 36 and the master cylinder push rod 9, the master cylinder piston 10 is internally pressurized in the master cylinder hydraulic cavity 12, and the brake fluid in the master cylinder hydraulic cavity 12 transmits braking force to each brake wheel cylinder 3 through a hydraulic pipeline.
The conventional braking can be divided into three processes of pressurization, pressure maintaining and pressure reducing.
a) Pressurization process
When a driver steps on the brake pedal 19, the normally closed electromagnetic valve 20 is opened, the normally open electromagnetic valve 21 is closed, and the reversing valve 30 is in the left position; four pressure increasing valves 13 connected with each brake cylinder 3 are all opened in a power-off mode, four pressure reducing valves 14 are all closed in a power-off mode, and brake fluid enters the brake cylinders 3 from a master cylinder hydraulic cavity 12 of the brake master cylinder 1 to build pressure.
b) Pressure maintaining process
When the electronic control unit ECU8 decides that the pressure of the brake system needs to be maintained, the four pressure increasing valves 13 are all powered on and closed, the four pressure reducing valves 14 are all powered off and closed, at this time, the brake fluid in the brake wheel cylinder 3 and the brake pipeline are all in an isolated state, and the brake pressure in the brake wheel cylinder 3 is also kept unchanged.
c) Pressure reduction process
When a driver releases the brake pedal 19 or the control strategy decides that the brake wheel cylinder 3 needs to reduce the pressure, the electronic control unit ECU8 controls the four pressure increasing valves 13 to be electrified and closed, the four pressure reducing valves 14 to be electrified and opened, at the moment, the brake fluid in the brake wheel cylinder 3 flows back to the liquid storage tank 4 through the pipelines of the pressure reducing valves 14, and the pressure reduction process of the brake wheel cylinder 3 is completed after the pressure is reduced.
The pedal feel simulator 7 simulates the process of pedal force:
in the conventional braking process, the pedal is completely decoupled, namely the driver is only responsible for giving the target brake pressure, the actual boosting process is completed by controlling the master cylinder driving device 2 and the brake master cylinder 1 and the solenoid valves by the electronic control unit ECU8, and the pedal feeling simulator 7 provides the same pedal feeling as the conventional braking system for the driver according to the pedal force and pedal displacement curve of the conventional braking system.
In the process, the normally closed electromagnetic valve 20 is opened, the normally open electromagnetic valve 21 is closed, the reversing valve 30 is in the left position, and when a driver steps on the brake pedal 19, brake fluid in the first hydraulic cavity 17 of the secondary master cylinder 5 flows to the hydraulic cavity of the pedal feel simulator 7 through the reversing valve 30 and acts on the simulator piston 24 to push the simulator piston 24 to move towards the bottom of the simulator cylinder body. When the pedal displacement is small, the simulator return spring 27 generates a pedal reaction force; with the increase of pedal displacement, the simulator piston 24 continues to move until the simulator rubber spring 28 is contacted with the bottom of the simulator cylinder, and then the simulator rubber spring 28 and the simulator return spring 27 are connected in parallel to jointly provide pedal reaction force, and due to the fact that the simulator rubber spring 28 has nonlinear elasticity, the nonlinear relation between pedal displacement and pedal force when the pedal displacement is large can be met, and the pedal feeling of a driver can be better simulated.
The adjustment of the directional control valve 30 by the ECU8 to meet the felt needs of the brake pedal 19 of different types of drivers can be achieved. When the change valve 30 is switched to the right position, the first hydraulic chamber 17 of the secondary master cylinder 5 is communicated with the reservoir tank 4, the brake fluid in the first hydraulic chamber 17 flows into the reservoir tank 4 through the change valve 30, the pedal feel simulator 7 does not provide the simulated pedal force at this time, the pedal force is provided by the return spring in the secondary master cylinder 5, and thus the generated pedal reaction force becomes small under the same pedal displacement. The electronic control unit ECU8 controls the switching of the directional control valve 30 between the left position and the right position, so that the adjustment of the pedal reaction force is realized, and the driver with different driving styles can be matched.
Control process of brake wheel cylinder pressure:
the utility model discloses an among the braking system, four pressure-increasing valves 13 and four relief pressure valves 14 all are the ooff valve, only open and close two kinds of states, for the control that realizes pressure, have inserted a linear air-vent valve 37 in each brake cylinder 3 through corresponding relief pressure valve 14 flow into the common pipeline of liquid storage pot 4. The ECU8 receives signals from the pedal stroke sensor 23 and the hydraulic pressure sensor 22, and after analysis and decision, controls the opening of the linear pressure regulating valve 37 according to the actual system requirement, i.e. controls the flow rate of the brake fluid flowing back to the reservoir 4 from the wheel cylinder 3, thereby realizing accurate pressure control.
2. Active braking:
because the utility model discloses a braking system footboard complete decoupling zero consequently can be independent of driver's pedal force execution braking operation. Taking an automobile emergency brake as an example, when an emergency situation occurs in front of an automobile, the electronic control unit ECU8 of the brake system sends a control signal to the rotating electrical machine 31 through decision-making judgment, and the master cylinder driving device 2 is used for quickly building pressure for the brake master cylinder 1. At the moment, four pressure increasing valves 13 in the brake system are all opened in a power-off mode, four pressure reducing valves 14 are all closed in a power-off mode, and brake fluid enters the brake wheel cylinders 3 from the brake master cylinder 1 to build pressure.
3. And (3) failure backup:
when the brake system is powered off or the electronic control unit ECU8 fails, the normally closed electromagnetic valve 20 is powered off and closed, the normally open electromagnetic valve 21 is powered off and opened, the reversing valve 30 is in the left position, the four pressure increasing valves 13 are powered off and opened, and the four pressure reducing valves 14 are powered off and closed. When the driver steps on the brake pedal 19, the brake fluid in the first hydraulic chamber 17 of the secondary master cylinder 5 flows into the pedal feel simulator 7 through the reversing valve 30, and the brake fluid in the second hydraulic chamber 18 of the secondary master cylinder 5 flows into the brake wheel cylinder 3, so that the wheels can obtain enough braking force, and the failure backup function is realized.
Claims (8)
1. A brake-by-wire system capable of simulating pedal feel, characterized in that: the brake master cylinder comprises a master cylinder push rod, a master cylinder piston and a master cylinder return spring, wherein a master cylinder hydraulic cavity is formed between the master cylinder piston and a cylinder body, and the master cylinder return spring is arranged in the master cylinder hydraulic cavity; the master cylinder driving device is connected with the master cylinder push rod and can push a master cylinder piston to be pressurized in a master cylinder hydraulic cavity; the master cylinder hydraulic cavity is connected with a brake wheel cylinder through a pipeline, and the brake wheel cylinder is connected with the liquid storage tank through a pipeline; a first piston and a second piston are sequentially assembled in the secondary main cylinder, a first hydraulic cavity and a second hydraulic cavity are sequentially formed among the first piston, the second piston and the bottom of the cylinder body, return springs are arranged in the first hydraulic cavity and the second hydraulic cavity, the pedal push rod penetrates through the front end of the secondary main cylinder to be connected with the first piston, the first hydraulic cavity of the secondary main cylinder is connected with the pedal feeling simulator through a pipeline, the second hydraulic cavity of the secondary main cylinder is connected with the liquid storage tank through a pipeline provided with a normally closed electromagnetic valve respectively, and is connected with the brake wheel cylinder through a pipeline provided with a normally open electromagnetic valve; and the electronic control unit ECU is respectively connected with the normally closed electromagnetic valve and the normally open electromagnetic valve.
2. The brake-by-wire system that can simulate a pedal feel according to claim 1, wherein: a pressure increasing valve is arranged on a pipeline between the master cylinder hydraulic cavity and the brake wheel cylinder, and a pressure reducing valve is arranged on a pipeline between the brake wheel cylinder and the liquid storage tank; the pressure increasing valve is a normally open type electromagnetic valve, and the pressure reducing valve is a normally closed type electromagnetic valve; the pressure increasing valve and the pressure reducing valve are respectively connected with the electronic control unit ECU.
3. A brake-by-wire system capable of simulating pedal feel according to claim 2, wherein: the hydraulic pressure sensor is connected with each pressure increasing valve of the master cylinder hydraulic cavity and each brake wheel cylinder, and measures the hydraulic pressure of the liquid outlet of the master cylinder hydraulic cavity and the hydraulic pressure of each brake wheel cylinder; the pedal stroke sensor is arranged on the pedal push rod and used for detecting displacement data of the pedal push rod; the hydraulic pressure sensor and the pedal travel sensor are respectively connected with the electronic control unit ECU and transmit data to the electronic control unit ECU in real time.
4. The brake-by-wire system that can simulate a pedal feel according to claim 1, wherein: the pedal feel simulator is internally divided into a hydraulic cavity and a spring cavity by a simulator piston, and the first hydraulic cavity of the secondary master cylinder is connected with the hydraulic cavity of the pedal feel simulator through a pipeline; the simulator is characterized in that a simulator return spring and a simulator rubber spring are arranged in the spring cavity, the simulator return spring is connected between the simulator piston and the bottom of the simulator cylinder body, the simulator rubber spring is located on the inner side of the simulator return spring, and one end of the simulator rubber spring is fixed on the simulator piston.
5. The brake-by-wire system that can simulate a pedal feel according to claim 4, wherein: a one-way valve is arranged on a pipeline between the first hydraulic cavity of the secondary master cylinder and the pedal feel simulator, and when the first piston of the secondary master cylinder is reset, brake fluid in the hydraulic cavity of the pedal feel simulator flows through the one-way valve and returns to the first hydraulic cavity of the secondary master cylinder; a reversing valve is connected in parallel with the one-way valve, the reversing valve is a two-position five-way electromagnetic valve, a liquid inlet is connected with a first hydraulic cavity of the secondary main cylinder through a pipeline, a left liquid outlet is in a normally open state and is connected with a hydraulic cavity of the pedal feeling simulator, and a right liquid outlet is in a normally closed state and is connected with a liquid storage tank; the reversing valve is connected with the electronic control unit ECU through a line, and the electronic control unit ECU controls reversing.
6. The brake-by-wire system that can simulate a pedal feel according to claim 1, wherein: the liquid storage tank is respectively connected with liquid inlets of a main cylinder hydraulic cavity of the brake main cylinder and a first hydraulic cavity and a second hydraulic cavity of the secondary main cylinder through pipelines, and brake liquid is supplemented into the main cylinder hydraulic cavity, the first hydraulic cavity and the second hydraulic cavity.
7. The brake-by-wire system that can simulate a pedal feel according to claim 1, wherein: the master cylinder driving device comprises a rotating motor, a pinion, a bull gear, a crank, a connecting rod and a sliding block, wherein an output shaft of the rotating motor and the pinion are coaxially arranged, the bull gear is meshed with the pinion, one end of the crank is fixed at the center of the bull gear and is arranged along the radial direction of the bull gear, the other end of the crank is hinged with the connecting rod, the other end of the connecting rod is hinged with the sliding block, the sliding block is connected with a master cylinder push rod of the brake master cylinder, and the sliding block is arranged; the rotating motor is connected with the electronic control unit ECU, and the electronic control unit ECU sends a control signal to control the rotation of the rotating motor.
8. A brake-by-wire system capable of simulating pedal feel according to claim 2, wherein: and a linear pressure regulating valve is also arranged on a pipeline between the pressure reducing valve of the brake wheel cylinder and the liquid storage tank, is a normally open electromagnetic valve with adjustable duty ratio, is connected with the electronic control unit ECU through a circuit, and is controlled to regulate the opening degree through the electronic control unit ECU.
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| CN202020257157.3U CN211617660U (en) | 2020-03-05 | 2020-03-05 | Brake-by-wire system capable of simulating pedal feel |
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| CN202020257157.3U CN211617660U (en) | 2020-03-05 | 2020-03-05 | Brake-by-wire system capable of simulating pedal feel |
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| CN111301378A (en) * | 2020-03-05 | 2020-06-19 | 吉林大学 | Controllable drive-by-wire braking system of simulation footboard sensation |
| CN112644526A (en) * | 2020-12-17 | 2021-04-13 | 北京北九方科贸有限公司 | Hydraulic adjusting pedal |
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| CN111301378A (en) * | 2020-03-05 | 2020-06-19 | 吉林大学 | Controllable drive-by-wire braking system of simulation footboard sensation |
| CN111301378B (en) * | 2020-03-05 | 2024-01-26 | 吉林大学 | Controllable drive-by-wire braking system of simulation footboard sensation |
| CN112644526A (en) * | 2020-12-17 | 2021-04-13 | 北京北九方科贸有限公司 | Hydraulic adjusting pedal |
| CN113074962A (en) * | 2021-04-21 | 2021-07-06 | 吉林大学 | Vehicle braking and steering system integrated test bench |
| CN113074962B (en) * | 2021-04-21 | 2022-06-14 | 吉林大学 | Vehicle braking and steering system integrated test bench |
| CN115447545A (en) * | 2021-06-08 | 2022-12-09 | 上海同驭汽车科技有限公司 | Pedal feel simulation device for line control power system |
| CN114228683A (en) * | 2021-12-28 | 2022-03-25 | 江苏恒力制动器制造有限公司 | Electronic hydraulic brake system and control method thereof |
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| CN114750733A (en) * | 2022-03-16 | 2022-07-15 | 清华大学 | Brake-by-wire system and control method for automobile |
| CN115009247A (en) * | 2022-07-08 | 2022-09-06 | 燕山大学 | EHB drive-by-wire braking system with redundancy function |
| CN115009247B (en) * | 2022-07-08 | 2023-09-26 | 燕山大学 | EHB line control braking system with redundancy function |
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