CN103950445A - Hydraulic double-motor driving electronic hydraulic braking system - Google Patents

Abstract

A hydraulic dual-motor driven electronic hydraulic braking system, comprising: brake pedal; brake master cylinder; secondary master cylinder; fluid storage tank; pedal displacement sensor; hydraulic pressure sensor; electronic control unit ECU; first electronic control unit The linear motion module and the second electronically controlled linear motion module are used to actively control the hydraulic braking force and pedal force of the system; the electronic stability control module ESC is used to adjust the hydraulic braking force of each wheel cylinder; the tee is used to connect The hydraulic pipeline between the brake master cylinder and the secondary master cylinder and the inlet of the electronic stability control module ESC module. The invention can utilize the driver's pedal force to build pressure, and realize active control of the pedal force while eliminating the need for a pedal force simulator with a complex structure, ensuring the feeling of the brake pedal, and can correctly reflect the driver's braking intention, realizing The hydraulic pressure is actively controlled to meet the braking requirements of the vehicle, and can maximize the recovery of braking energy, with precise control and fast response.

Description

A hydraulic dual-motor driven electronic hydraulic braking system

technical field

The invention belongs to the technical field of automobiles, and relates to automobile braking technology, in particular to an electronic hydraulic braking system driven by a motor.

Background technique

Due to energy shortages and increasingly prominent environmental problems, electric vehicles have become the main direction of the future development of the automotive industry due to their clean and pollution-free, high energy efficiency, diverse energy sources, simple structure, and convenient maintenance. Restrictions, short driving range and high cost of electric vehicles; with the improvement of intelligent requirements, and the need to solve problems such as traffic accidents and traffic congestion, many auto companies such as Continental and General Motors are conducting research on autonomous vehicles, and the development of autonomous driving technology fast. The braking system is a crucial system in the safety performance of automobiles. How to recover as much braking energy as possible, increase the mileage of electric vehicles, how to improve the active safety of vehicles, and not rely on manpower for automatic driving of vehicles? motion becomes a problem that needs to be solved.

Electro-hydraulic brake system (EHB), as a relatively new type of brake system, is a kind of brake-by-wire system. It replaces some mechanical components with electronic components, and there is no direct connection between the brake pedal and the brake wheel cylinder. Connected, use the sensor to collect the driver's operation information and use it as the control intention, and the braking operation is completely completed by the hydraulic actuator. During the braking process of new energy vehicles, when the hydraulic braking force is applied to the wheels, the drive motor works in the state of regenerative braking and also applies regenerative braking force to the wheels, so that the effective braking of the vehicle is completed while regenerative braking is generated. energy and store it in an energy storage device for reuse.

The electronic hydraulic braking system is mainly composed of a brake pedal, a pedal displacement sensor (or a pedal angle sensor), an electronic control unit (ECU), and a hydraulic actuator. The pedal displacement sensor (pedal angle sensor) is used to detect the pedal displacement (pedal rotation angle), and then convert the displacement (rotation angle) signal into an electrical signal and send it to the ECU to regulate the braking force.

In 1994, Analog company developed a set of control system for electronically controlled hydraulic braking system by means of Saber simulation; in 2001, at the Frankfurt Motor Show, Bosch exhibited the developed electronic hydraulic braking system, which was equipped on the 5th floor of Benz company. After that, Bosch and Daimler Chrysler began to study the EHB system for commercial use, and assembled it on the Mercedes E-class car in 2002; in 2002, Ford Motor Company's Focus FCV braking system adopted The EHB system developed by Continental of Germany; in 2003, Continental Teves also started its EHB program, which was installed on some concept cars of Volkswagen. Compared with the traditional hydraulic braking system, the electronic hydraulic braking system cancels the bulky vacuum booster, has a more compact structure, is convenient to control, reduces braking noise, and improves braking efficiency.

The general electronic hydraulic braking system realizes the active control of the hydraulic braking force of the hydraulic braking system through the joint action of high-pressure accumulators, motors and pumps, but this technology is not yet mature, and there are still hidden dangers in reliability and safety. To ensure the pedal feeling or need to use a pedal simulator to simulate the pedal feeling; in addition, it does not make full use of manpower, that is, the pedal force of the driver to brake, resulting in a certain degree of waste of energy.

Replace the high-voltage accumulator and pump in the electronic hydraulic braking system with the motor and mechanical structure, transmit the signal between the electronic control unit and the actuator through the control line, and use the motion adjustment device to convert the rotational motion of the motor into linear motion to push The master cylinder makes it produce the desired movement, so as to realize the active control and adjustment of hydraulic pressure. There is no hydraulic pipeline between the brake pedal and the brake master cylinder, so there are no problems such as hydraulic pipeline leakage and high-pressure accumulator safety hazards. It is more reliable and safe, and there is no need to modify the brake master cylinder, which reduces costs. The motor drives the hydraulic system to brake, which is convenient for active control of the hydraulic pressure, and can actively control the pedal force through the mechanical mechanism, eliminating the need for a complex pedal simulator, and realizing ABS while making full use of the pedal force pressed by the driver. , TCS and other functions. Self-driving vehicles need to brake independently of human power, and this form of compound braking system also meets the requirements.

Contents of the invention

The purpose of the present invention is to provide a hydraulic dual-motor driven electronic hydraulic braking system, in order to accurately identify the driver's braking intention, make full use of manpower, realize the active control of hydraulic pressure, meet the braking requirements of automatic driving vehicles, and realize The active control of the pedal ensures the feeling of the pedal and recovers more braking energy; the mechanical connection between the brake pedal and the brake master cylinder improves the safety and reliability of the electronic hydraulic brake system.

In order to achieve the above object, the solution of the present invention is: a hydraulic dual-motor driven electronic hydraulic braking system, which includes: a brake pedal; a brake master cylinder; a secondary master cylinder; a liquid storage tank; a pedal displacement sensor; The hydraulic pressure sensor; the electronic control unit ECU; also includes the first electronically controlled linear motion module and the second electronically controlled linear motion module, which are used to actively control the hydraulic braking force and pedal force of the system; the electronic stability control module ESC, which is used for Adjust the hydraulic braking force of each wheel cylinder; three-way, used to connect the hydraulic pipeline between the brake master cylinder and the secondary master cylinder and the inlet of the electronic stability control module ESC module.

Further, the first electronically controlled linear motion module and the second electronically controlled linear motion module include a motor and a motion adjustment mechanism, wherein the motion adjustment mechanism of the first electronically controlled linear motion module is connected to the brake pedal through one end of a built-in push rod, One end is connected with the first piston of the brake master cylinder; the motion adjustment mechanism of the second electronically controlled linear motion module is directly connected with the first piston of the secondary master cylinder.

The motor of the first electronically controlled linear motion module provides torque according to the ideal pedal force and the actual hydraulic pressure in the brake master cylinder to ensure the driver's pedal feeling; The size of the power provides torque to ensure the required hydraulic braking force.

The motion adjustment mechanism converts the rotational motion of the motor into linear motion.

It also includes a solenoid valve, which ensures that the braking system has a certain braking efficiency in failure mode through switching action.

The solenoid valves include two normally open solenoid valves respectively located at the oil outlets of the first working chamber and the second working chamber of the brake master cylinder and respectively located at the first working chamber and the second working chamber of the secondary master cylinder. Two normally closed solenoid valves at the oil outlet of the chamber are used to control the hydraulic pipeline to achieve braking in different modes.

The brake master cylinder, the secondary master cylinder, the solenoid valve and the electronic stability control module ESC are connected through hydraulic pipelines; The pipeline is connected to an oil inlet hole of the electronic stability control module ESC module through a tee, and the hydraulic pipeline connected to the oil outlet hole of the second chamber of the brake master cylinder and the secondary master cylinder is also connected to the The other oil inlet hole of the ESC module is connected.

The hydraulic pressure sensor is located between the normally open solenoid valve at the oil outlet of the brake master cylinder and the tee on the corresponding pipeline, and is used to obtain the pressure of the hydraulic pipeline.

In other words, the present invention provides a hydraulic dual-motor driven electronic hydraulic braking system, including: brake pedal; brake master cylinder; secondary master cylinder; liquid storage tank for storing brake fluid; pedal displacement sensor, It is used to obtain the displacement signal of the driver stepping on the brake pedal; the hydraulic pressure sensor is used to obtain the pressure of the hydraulic line; the electronic control unit (ECU) is used to receive the sensor signal, calculate and issue control instructions; two electronic control lines The motion module, including the rotary motor and the motion adjustment mechanism that converts the motor rotary motion into linear motion, is used to actively control the hydraulic braking force and pedal force of the system; the electronic stability control module (ESC) is used to adjust each wheel cylinder. Hydraulic braking force; three-way, used to connect the hydraulic pipeline between the brake master cylinder and the secondary master cylinder and the inlet of the ESC module; solenoid valve, used to open and close the brake master cylinder and the secondary master cylinder The hydraulic pipeline between the primary master cylinder and the inlet of the ESC module ensures that the braking system has a certain braking efficiency in failure mode through switch action.

The first linear motion module is connected with the brake master cylinder, and converts the rotational motion of the motor into linear motion according to the signal of the electronic control unit, and is used to actively control the pedal force of the system; the second linear motion module, It is connected with the secondary master cylinder, and converts the rotary motion of the motor into linear motion according to the signal of the electronic control unit, so as to actively control the hydraulic pressure of the system.

The first electronically controlled linear motion module and the second electronically controlled linear motion module include a motor and a motion adjustment mechanism. One end of the motion adjustment mechanism of the first electronically controlled linear motion module is connected to the brake pedal through a built-in push rod, and the other end is connected to the brake master. The first piston of the cylinder is connected, and the motion adjustment mechanism of the second electronically controlled linear motion module is directly connected with the first piston of the secondary master cylinder. The two normally open solenoid valves are located at the oil outlets of the first working chamber and the second working chamber of the brake master cylinder, and the two normally closed solenoid valves are located at the oil outlets of the first working chamber and the second working chamber of the secondary master cylinder. The solenoid valve is connected to the brake master cylinder, the secondary master cylinder and the ESC module through hydraulic lines. The hydraulic pipeline connected to the oil outlet hole of the first cavity of the brake master cylinder and the secondary master cylinder is connected to an oil inlet hole of the ESC module through a tee, and connected to the oil outlet hole of the second cavity of the brake master cylinder and the secondary master cylinder The connected hydraulic pipeline is also connected with another oil inlet hole of the ESC module through a tee. A hydraulic pressure sensor is placed between the normally open solenoid valve at the oil outlet of the brake master cylinder and the tee on the corresponding pipeline.

Preferably, the motion adjustment mechanism in the first and second electronically controlled linear motion modules includes a worm gear and rack and pinion mechanism, a screw-nut mechanism or a ball screw.

Preferably, the solenoid valve is a high-speed switching solenoid valve (controlled by PWM) or a linear solenoid valve (controlled by position feedback).

Compared with the existing electronic hydraulic braking system, the electronic hydraulic braking system driven by hydraulic double motors of the present invention has the following advantages:

1. The dual-motor cooperative control motion adjustment mechanism is adopted, which reduces the power of the motor, improves the life of the motor, and has a fast response speed. It can control the hydraulic braking force in real time and actively adjust it. When a certain motor fails, another motor can be used as the brake. The braking system provides hydraulic braking force.

2. Adjust the size of the hydraulic braking force according to the changing regenerative braking force generated by the electric vehicle drive motor to provide the total braking force, make full use of manpower, correctly reflect the driver's braking intention and maximize the regenerative braking energy.

3. The motor of the first electronically controlled linear motion module controls the motion adjustment mechanism after receiving the signal from the electronic control unit ECU. The motion adjustment mechanism can apply force to the push rod connected to the brake pedal to realize active control of the pedal force and ensure The driver's brake pedal feeling is improved, and the pedal simulator with complex structure is omitted.

4. The self-driving vehicle is required to be able to brake without the driver’s pedal force. At this time, the electronic control ECU adjusts the motors of the first and second electronically controlled linear motion modules according to the received signal to generate a hydraulic brake. power to meet the braking requirements of autonomous driving.

5. The mechanical connection between the brake pedal and the brake master cylinder reduces the risk of system failure, and the driver's pedal force is also a part of the total braking force. When the first electronically controlled linear motion module or the second electronically controlled linear motion module fails, the brake pedal can still provide the braking force required by the system through the mechanical connection with the unfailed electronically controlled linear motion module; when the two electronically controlled linear motion modules When the linear motion module fails at the same time, the driver slams on the brake pedal, and the system can also generate a certain amount of braking force, ensuring the reliability and safety of the vehicle braking system.

Description of drawings

Fig. 1 is a schematic diagram of an embodiment of a hydraulic dual-motor driven electronic hydraulic braking system according to the present invention.

The label in the accompanying drawing indicates:

1—brake pedal; 2—motor; 3—worm gear mechanism (not completely drawn in the figure); 4—fluid storage tank; 5—first piston of brake master cylinder; 6—first working chamber of brake master cylinder; 7—return spring in the first working chamber of the brake master cylinder; 8—the second piston of the brake master cylinder; 9—return spring in the second working chamber of the brake master cylinder; 10—the second working chamber of the brake master cylinder ; 11—brake master cylinder; 12—pedal displacement sensor; 13—rack and pinion mechanism (not completely drawn in the figure); 14, 17—normally closed solenoid valve; 15,16—normally open solenoid valve; 18—hydraulic pressure Sensor; 19—first piston of secondary master cylinder; 20—first working chamber of secondary master cylinder; 21—second piston of secondary master cylinder; 22—second working chamber of secondary master cylinder; 23—secondary master cylinder ; 24—rack and pinion mechanism (not completely drawn in the figure); 25—motor; 26—worm gear mechanism (not completely drawn in the figure); 27—ESC module; 28—the first electronically controlled linear motion module; 29—the first 2. Electronically controlled linear motion module; 30—electric control unit; 31, 32—linear motion mechanism; 33, 34, 35, 36, 37—control circuit; 38—push rod; 39, 40—three links.

Detailed ways

The present invention will be further described below in conjunction with the examples shown in the accompanying drawings.

As shown in Figure 1, the hydraulic dual-motor driven electronic hydraulic braking system mainly includes a brake pedal 1, a first electronically controlled linear motion module 28, a second electronically controlled linear motion module 29, a brake master cylinder 11, a secondary Master cylinder 23, solenoid valve 14, solenoid valve 15, solenoid valve 16, solenoid valve 17, pedal displacement sensor 12, hydraulic pressure sensor 18, ESC module 27, liquid storage tank 4, electronic control unit 30 and control lines 33, 34, 35, 36, 37. The first electronically controlled linear motion module 28 and the second electronically controlled linear motion module 29 include a motor and a motion adjustment mechanism. The motion adjustment mechanism of the first electronically controlled linear motion module is connected to the brake pedal through a built-in push rod 38 at one end, and one end to the brake pedal. The first piston of the brake master cylinder is connected, and the motion adjustment mechanism of the second electronically controlled linear motion module is directly connected with the first piston of the secondary master cylinder. Two normally open solenoid valves 15 and 16 are located at the oil outlets of the first and second working chambers of the brake master cylinder, and two normally closed solenoid valves 14 and 17 are located at the first and second working chambers of the secondary master cylinder. Cavity oil hole. The solenoid valve is connected with the brake master cylinder 11 , the secondary master cylinder 23 and the ESC module 27 through hydraulic pipelines. The hydraulic pipeline connected to the oil outlet hole of the first cavity of the brake master cylinder and the secondary master cylinder is connected to an oil inlet hole of the ESC module through a tee 40, and is connected to the oil outlet of the second cavity of the brake master cylinder and the secondary master cylinder The hydraulic pipeline connected to the hole is connected with another oil inlet hole of the ESC module through a tee 39 . A hydraulic pressure sensor is placed between the normally open solenoid valve at the oil outlet of the brake master cylinder and the tee on the corresponding pipeline.

In this exemplary embodiment, the motion adjustment mechanisms 31, 32 are a combination of a worm gear mechanism and a rack and pinion mechanism. Preferably, the rack in the motion adjustment mechanism 31 is hollow and has a built-in push rod 38 .

The specific working process of the hydraulic dual-motor driven electronic hydraulic braking system of the present invention is as follows: the driver depresses the brake pedal 1, the displacement sensor 12 obtains the pedal displacement signal, receives the driver's braking intention, and the electronic control unit 30 according to the collected The received signal obtains the required hydraulic braking force P _h in this braking, and calculates the adjustment force F ₂ required by the second electronically controlled linear motion module 29 (F ₂ =P _h ·A ₂ , A ₂ is Secondary master cylinder piston area), the solenoid valves 14, 15, 16, 17 are opened, and the motor 25 is driven through the control circuit 34 to push the first piston 19 of the secondary master cylinder to move linearly. When the first piston 19 blocks the first compensation hole The first working chamber 20 of the secondary master cylinder starts to build up pressure, and then pushes the second piston 21 to move linearly. When the second piston 21 blocks the second compensation hole, the second working chamber 22 starts to build up pressure, and the brake fluid passes through the solenoid valve 14, 17 and the hydraulic pipeline flow to the ESC module 27, and then flow to each wheel cylinder to generate braking force. At the same time, the electronic control unit 30 obtains the ideal pedal force F _{target_p} corresponding to the received pedal displacement signal according to the ideal relationship curve between the brake pedal force and the pedal stroke, and combines the hydraulic pressure P1 measured by the hydraulic pressure sensor ₁₈ to calculate the first The adjustment force _F 1 to be provided by the electronically controlled linear motion module 28 (F ₁ =P ₁ ·A ₁ -F _{target_p} ·i, A ₁ is the piston area of the brake master cylinder, i is the lever ratio of the brake pedal), through the control circuit 35 regulates the moment of motor 2, guarantees driver's pedal feeling.

When the required hydraulic braking force of the system changes, increases or decreases Δp due to the change of the vehicle running state, the electronic control unit 30 adjusts the torque of the motor 25 so that the adjustment force of the second electronically controlled linear motion module 29 is F ₂ (F ₂ =(P _h ±Δ _p )·A ₂ , A ₂ is the piston area of the secondary master cylinder), and at the same time obtain the adjustment force F ₁ required by the first electronically controlled linear motion module 28 (F ₁ =(P _h ±Δp ) A ₁ -F _{target_p} i, A ₁ is the piston area of the brake master cylinder, and i is the brake pedal lever ratio), the torque of the motor 2 is adjusted through the control circuit 35 to ensure that the driver's pedal feeling remains unchanged.

According to national regulations, the braking system must take into account the occurrence of failure and the failure of some braking components, and it must also be able to transmit the force of the driver's pedaling to the braking system for a certain intensity of braking. The electronic hydraulic braking system driven by hydraulic double motors of the present invention is also designed with a failure protection scheme.

When a certain pipeline between the ESC module 27 and the brake master cylinder 11 and the secondary master cylinder 23 fails when the brake starts or the brake is in progress, the second work with the brake master cylinder 11 and the secondary master cylinder 23 As an example, the failure of a pipeline connected to the cavity is taken as an example. The electronic control unit 30 receives the failure information, and the solenoid valves 14 and 16 are closed. At this time, the second working chamber of the brake master cylinder 11 and the secondary master cylinder 23 can be approximately regarded as a rigid body. Using its first working chamber for braking, the pedal feel is guaranteed while actively controlling the hydraulic pressure. The working condition of the system is similar when a pipeline connected to the first working chamber of the brake master cylinder 11 and the secondary master cylinder 23 fails.

Motor 2 cannot provide torque at the start of braking or during braking, or the motion adjustment mechanism 31 is damaged so that motion cannot be transmitted. Control the motor 25 in the linear motion module 29 to adjust (F ₁ =P _h A ₂ , A ₂ is the piston area of the secondary master cylinder), drive the motion adjustment mechanism 32, and push the first piston 19 of the secondary master cylinder to do the desired Linear movement, together with the hydraulic pressure generated by the driver's pedal force, brakes each wheel cylinder.

The motor 25 cannot provide torque at the start of braking or the braking is in progress, or the motion adjustment mechanism 32 is damaged so that the motion cannot be transmitted. The motor 2 in the first electronically controlled linear motion module 28 is adjusted (F ₁ =P _h A ₁ , A ₁ is the piston area of the brake master cylinder), drives the movement adjustment mechanism 31 to push the first piston of the brake master cylinder 5 Make the desired linear motion.

When the first and second electronically controlled linear motion modules fail simultaneously at the start of braking or during braking, the system transmits fault information to the electronic control unit 30, the solenoid valves 14 and 17 are closed, and the solenoid valves 15 and 16 are opened. At this time, the driver Slam on the brake pedal and directly push the brake master cylinder through the push rod 38. Although there is no power assist, enough braking force cannot be provided, but in emergency braking, this certain degree of braking force still has a greater impact on the safety of the driver. big help.

The above description of the embodiments is for those of ordinary skill in the art to understand and apply the present invention. It is obvious that those skilled in the art can easily make various modifications to these embodiments, and apply the general principles described here to other embodiments without creative effort. Therefore, the present invention is not limited to the embodiments herein. Improvements and modifications made by those skilled in the art according to the disclosure of the present invention without departing from the scope of the present invention should fall within the protection scope of the present invention.

Claims (8)

1. A hydraulic dual-motor driven electronic hydraulic braking system, which includes: brake pedal; brake master cylinder; secondary master cylinder; liquid storage tank; pedal displacement sensor; hydraulic pressure sensor; electronic control unit ECU; It is characterized in that it also includes a first electronically controlled linear motion module and a second electronically controlled linear motion module, which are used to actively control the hydraulic braking force and pedal force of the system; the electronic stability control module ESC is used to adjust the pressure of each wheel cylinder. hydraulic braking force; a tee, used to connect the hydraulic pipelines between the brake master cylinder and the secondary master cylinder and the inlet of the electronic stability control module ESC module. 2. The hydraulic dual-motor driven electronic hydraulic braking system according to claim 1, characterized in that: The first electronically controlled linear motion module and the second electronically controlled linear motion module include a motor and a motion adjustment mechanism, wherein one end of the motion adjustment mechanism of the first electronically controlled linear motion module is connected to the brake pedal through a built-in push rod, and one end is connected to the brake pedal. The first piston of the brake master cylinder is connected; the motion adjustment mechanism of the second electronically controlled linear motion module is directly connected with the first piston of the secondary master cylinder. 3. The hydraulic dual-motor driven electronic hydraulic braking system according to claim 2, characterized in that: The motor of the first electronically controlled linear motion module provides torque according to the ideal pedal force and the actual hydraulic pressure in the brake master cylinder to ensure the driver's pedal feeling; The size of the power provides torque to ensure the required hydraulic braking force. 4. The hydraulic dual-motor driven electronic hydraulic braking system according to claim 2, characterized in that: The motion adjustment mechanism converts the rotational motion of the motor into linear motion. 5. The hydraulic dual-motor driven electro-hydraulic braking system according to claim 1, characterized in that it further comprises a solenoid valve, which ensures that the braking system has a certain braking efficiency in failure mode through switching action. 6. The hydraulic dual-motor driven electronic hydraulic braking system according to claim 5, characterized in that: The solenoid valves include two normally open solenoid valves respectively located at the oil outlets of the first working chamber and the second working chamber of the brake master cylinder and respectively located at the first working chamber and the second working chamber of the secondary master cylinder. Two normally closed solenoid valves at the oil outlet of the chamber are used to control the hydraulic pipeline to achieve braking in different modes. 7. The hydraulic dual-motor driven electronic hydraulic braking system according to claim 6, characterized in that: The brake master cylinder, the secondary master cylinder, the solenoid valve and the electronic stability control module ESC are connected through hydraulic pipelines; The pipeline is connected to an oil inlet hole of the electronic stability control module ESC module through a tee, and the hydraulic pipeline connected to the oil outlet hole of the second chamber of the brake master cylinder and the secondary master cylinder is also connected to the The other oil inlet hole of the ESC module is connected. 8. The hydraulic dual-motor driven electronic hydraulic braking system according to claim 1, characterized in that: The hydraulic pressure sensor is located between the normally open solenoid valve at the oil outlet of the brake master cylinder and the tee on the corresponding pipeline, and is used to obtain the pressure of the hydraulic pipeline.