CN113246939B - Double-hydraulic-cylinder type line control brake system - Google Patents
Double-hydraulic-cylinder type line control brake system Download PDFInfo
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- CN113246939B CN113246939B CN202110517619.XA CN202110517619A CN113246939B CN 113246939 B CN113246939 B CN 113246939B CN 202110517619 A CN202110517619 A CN 202110517619A CN 113246939 B CN113246939 B CN 113246939B
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- 238000006073 displacement reaction Methods 0.000 claims abstract description 25
- 239000007788 liquid Substances 0.000 claims abstract description 24
- 238000000034 method Methods 0.000 claims abstract description 12
- 230000000694 effects Effects 0.000 claims abstract description 10
- 238000007789 sealing Methods 0.000 claims description 11
- 230000009977 dual effect Effects 0.000 claims description 6
- 238000007906 compression Methods 0.000 claims description 5
- 230000008569 process Effects 0.000 abstract description 10
- 239000003921 oil Substances 0.000 description 38
- 230000009471 action Effects 0.000 description 13
- 230000006835 compression Effects 0.000 description 3
- 238000011161 development Methods 0.000 description 3
- 238000004146 energy storage Methods 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 239000010720 hydraulic oil Substances 0.000 description 3
- 206010063385 Intellectualisation Diseases 0.000 description 2
- 238000013461 design Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
- B60T13/00—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems
- B60T13/10—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release
- B60T13/66—Electrical control in fluid-pressure brake systems
- B60T13/72—Electrical control in fluid-pressure brake systems in vacuum systems or vacuum booster units
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
- B60T13/00—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems
- B60T13/10—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release
- B60T13/12—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release the fluid being liquid
- B60T13/14—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release the fluid being liquid using accumulators or reservoirs fed by pumps
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- Braking Systems And Boosters (AREA)
Abstract
The invention discloses a double-hydraulic cylinder type wire control brake system, which comprises: the brake system comprises a liquid storage tank, a displacement sensor, a brake pedal, a vacuum booster, a first push rod, a second push rod, a first hydraulic cylinder, a first magnet, a spring, a second magnet, a connecting rod, a second hydraulic cylinder, a ball screw structure, a second hydraulic cylinder piston, a motor and a control unit; according to the invention, the decoupling of the brake pedal and the brake master cylinder is realized by providing a combination form of two homopolar magnets and a nonlinear spring, so that the vibration generated in the brake-by-wire process is not transmitted to the brake pedal; through the boosting effect of the vacuum booster, high pressure can be quickly established by oil in the pipeline, the occupied space of a braking system is reduced, the cost is reduced, and oil leakage is prevented.
Description
Technical Field
The invention belongs to the technical field of automobile brake systems, and particularly relates to a double-hydraulic-cylinder type wire-controlled brake system.
Background
With the development of automobile technology, intellectualization, networking and electromotion are the development direction of future automobiles, and a brake-by-wire system is a key technology for realizing automobile intellectualization. Compared with the traditional brake system, the brake-by-wire system has the advantages of small volume and flexible assembly, can reduce the design and arrangement difficulty of the chassis, facilitates the arrangement of the whole automobile, and is favorable for realizing the modularized design of the automobile chassis. The brake-by-wire is the development direction of the future automobile brake technology, can deeply integrate an automobile automatic driving function module, and is the requirement of the times of intelligent automobiles, intelligent transportation and smart cities.
The existing brake-by-wire system mainly has two forms of an electronic hydraulic brake system (EHB) and an electronic mechanical brake system (EMB), wherein the EHB is flexibly controlled by an electronic system, and the hydraulic system is used as a standby system to provide power so as to ensure the brake capability of the system when the electronic part of the system fails, and the hydraulic system is not completely removed; the EMB system completely removes a hydraulic system, a motor generates braking force, the value of the braking force is controlled by an electronic controller, and the electronic controller of the EMB system sends a signal to the motor of the wheel braking module according to displacement and speed signals of an electronic pedal module sensor and in combination with signals of other sensors such as vehicle speed and the like to control the current and the rotor angle of the motor, so that the required braking force is generated, and the purpose of braking is achieved. However, the brake-by-wire system, which uses the wire connection to transmit energy and the data wire to transmit signals to control the braking of the wheel brake, is more susceptible to electromagnetic interference than the conventional hydraulic brake system, and needs to be further improved. In order to ensure that the online control system can be safely stopped when the online control system fails, a backup hydraulic system is designed in the system to ensure that the brake capability of the automobile is still ensured when the brake-by-wire system fails, and the driving safety is ensured.
In order to ensure that the brake capability of an automobile still exists when a brake-by-wire system fails, the conventional electronic hydraulic brake system faces some problems; firstly, the brake pedal feel is simulated, and because a vacuum booster is eliminated in most brake-by-wire systems, the brake pedal feel is simulated by adopting the rebound force obtained by compressing elastic elements (springs, rubber and the like), so that the brake pedal feel is inconsistent with the traditional pedal feel; secondly, in order to realize brake backup, two brake systems of hydraulic brake and electronic brake are simultaneously applied to the automobile brake system, when the electronic brake control fails, the hydraulic brake system can also realize brake, but because the two brake systems exist simultaneously, the structure is complex, the cost is higher, and the maintenance difficulty is increased. Thirdly, in such a brake system integrating hydraulic braking and electronic braking, in order to achieve an emergency hydraulic braking effect, a high-pressure energy storage device is usually separately arranged, but the high-pressure energy storage device has a risk of leakage due to the influences of road bump, vibration generated during automobile running and the like, and meanwhile, the high-pressure energy storage device occupies a large space, and further occupies an originally limited space of an automobile chassis system.
The Chinese invention patent application number is CN201810127268.X, the name is a mixed brake-by-wire system of front wheel EHB rear wheel EMB, and discloses a mixed brake-by-wire system which adopts an EHB system at the front shaft and an EMB system at the rear shaft, a high-pressure accumulator is arranged in the system to ensure that a hydraulic pipeline keeps certain pressure, hydraulic oil flows into a piston and compresses a spring at the inner side of the piston to simulate the feeling of a pedal, which is a current typical brake-by-wire system, but the invention has the following defects:
(1) the EHB and the EMB are adopted, so that the structure is complex, the cost is high, and the arrangement is difficult in a chassis system with limited space;
(2) the drive-by-wire system adopts a high-pressure accumulator to maintain the pressure in a pipeline, and the high-pressure accumulator has the risk of leakage due to vibration and bumping of the running automobile;
(3) the pedal feeling is simulated through the compression spring, the pedal feeling is inconsistent with that of a traditional hydraulic braking system adopting a vacuum booster, a driver cannot accurately grasp the braking process, and the braking safety and the driving safety are influenced.
Disclosure of Invention
In view of the above disadvantages of the prior art, the present invention provides a dual hydraulic cylinder brake-by-wire system, so as to overcome the problems of the prior art that the brake-by-wire system has a complex structure and is difficult to arrange, the risk of oil leakage exists, and vibration generated during braking is transmitted to the brake pedal; the invention not only can realize line control brake, but also can realize conventional hydraulic brake when the line control brake fails, and has low production cost, small brake distance and high safety; the decoupling of the brake pedal and the brake master cylinder is realized by providing a combination form of two homopolar magnets and a nonlinear spring, so that the vibration generated in the brake-by-wire process is not transmitted to the brake pedal; through the boosting effect of the vacuum booster, high pressure can be quickly established by oil in the pipeline, the occupied space of a braking system is reduced, the cost is reduced, and oil leakage is prevented.
In order to achieve the purpose, the technical scheme adopted by the invention is as follows:
the invention relates to a double-hydraulic cylinder type wire control brake system, which comprises: the brake system comprises a liquid storage tank, a displacement sensor, a brake pedal, a vacuum booster, a first push rod, a second push rod, a first hydraulic cylinder, a first magnet, a spring, a second magnet, a connecting rod, a second hydraulic cylinder, a ball screw structure, a second hydraulic cylinder piston, a motor and a control unit;
the displacement sensor is used for detecting a braking signal of a brake pedal, one end of the first push rod is connected with the brake pedal, the other end of the first push rod is connected with the vacuum booster, and the first push rod is used for pushing the vacuum booster; one end of the second push rod is connected with the vacuum booster, and the other end of the second push rod is connected with the first magnet; the first magnet and the second magnet are arranged in the first hydraulic cylinder, the radial length of the first magnet and the radial length of the second magnet are consistent with that of the hydraulic cylinder, the periphery of the first magnet and the second magnet is provided with a sealing ring, the first hydraulic cylinder is divided into two parts by the second magnet, one part is a first air chamber, and the other part is a first hydraulic chamber; the first magnet and the second magnet have the same polarity, a gap is formed between the first magnet and the second magnet and used for accommodating the spring, and two ends of the spring are respectively fixedly connected to the first magnet and the second magnet; one end of the connecting rod is fixedly connected to the second magnet, and the other end of the connecting rod is fixedly connected to the second hydraulic cylinder piston; the ball screw structure includes: the outer side wall of the lower end of the connecting rod is fixedly connected with the ball screw nut, a rotor shaft of the motor is fixedly connected with the ball screw shaft, balls are designed in the ball screw structure, the ball screw nut is sleeved on the ball screw shaft, and the balls are located between the ball screw nut and the ball screw shaft;
the second hydraulic cylinder piston is placed in a second hydraulic cylinder, the radial diameter of the second hydraulic cylinder piston is consistent with the radial size of the second hydraulic cylinder, and sealing rings are arranged on the periphery of the second hydraulic cylinder piston and divide the second hydraulic cylinder into a second air chamber and a second hydraulic chamber; the first hydraulic chamber and the second hydraulic chamber are respectively connected with the liquid storage tank through hydraulic pipelines, and the second air chamber is connected with the vacuum booster through an air pipe to provide negative pressure for the vacuum booster;
the first hydraulic chamber is respectively connected with the left rear wheel brake and the right rear wheel brake through hydraulic pipelines, and a pressure sensor and a normally closed solenoid valve are arranged in the pipelines; a normally open solenoid valve is arranged in the pipeline of the left rear wheel brake and the liquid storage tank, and a normally closed solenoid valve is arranged in the pipeline of the right rear wheel brake and the liquid storage tank; the second hydraulic chamber is respectively connected with the left front wheel brake and the right front wheel brake through hydraulic pipelines, a pressure sensor and a normally closed solenoid valve are arranged in the pipelines, and a normally open solenoid valve is arranged in the pipelines of the left front wheel brake and the liquid storage tank, and a normally closed solenoid valve is arranged in the pipelines of the right front wheel brake and the liquid storage tank;
the control unit is connected with the normally open electromagnetic valve, the normally closed electromagnetic valve and the motor circuit through leads and sends control signals to the motor and the electromagnetic valves.
Furthermore, the second magnet is a whole magnet or a magnet fixedly connected with the outer side of the piston.
Further, the size of the gap between the first magnet and the second magnet is selected and considered to be matched with the characteristics of the spring, and the optimal pedal feeling is obtained by coordinating the repulsive force of the magnets with the elastic force of the spring.
Furthermore, the second air chamber is a vacuum chamber or is filled with partial air, and is connected with a vacuum booster to generate different air pressure differences so as to realize different boosting effects.
Furthermore, the spaces of the first hydraulic chamber and the second hydraulic chamber are different in size, and the spaces in the first hydraulic chamber and the second hydraulic chamber are continuously reduced through the movement of the second magnet and the second hydraulic cylinder piston, so that the brake oil is compressed, and the brake oil is changed into high-pressure oil; the method specifically comprises the following steps: the space of the first hydraulic chamber is larger than that of the second hydraulic chamber, and in the same compression process, the oil pressure generated by the second hydraulic chamber is larger than that generated by the first hydraulic chamber, so that different hydraulic braking forces are realized.
The invention has the beneficial effects that:
1) when a vehicle needs to be braked, if an automobile brake-by-wire system is normal, a brake signal acquired by a displacement sensor is transmitted to a motor through a control unit, the motor rotates, a connecting rod is driven to translate through a ball screw structure, high-pressure oil is generated, and the high-pressure oil flows into a wheel brake to be braked; if the brake-by-wire system of the automobile breaks down, a driver can step on a brake pedal through manpower, the second hydraulic cylinder piston is pushed to generate hydraulic oil with enough pressure through the boosting effect of the vacuum booster, the hydraulic oil flows into the wheel brake, braking force is generated, braking is implemented, a brake failure safety backup is provided, and the requirement of the brake-by-wire automobile on the safety of the brake system is met.
2) The invention adopts the structure of double hydraulic cylinders and double pistons, so that the conventional hydraulic brake system is combined with the brake-by-wire, thereby reducing the space occupied by the brake system and lowering the production cost.
3) The invention adopts the structure of the vacuum booster, and realizes the feeling consistent with that of the traditional brake pedal.
4) The invention adopts two magnets with the same polarity and a nonlinear spring, realizes the decoupling between the brake pedal and the hydraulic cylinder, and avoids the problem that unpleasant vibration generated in the braking process is transferred to the brake pedal.
Drawings
FIG. 1 is a schematic diagram of the system of the present invention;
FIG. 2 is a schematic view showing the connection relationship between the motor, the ball screw structure and the connecting rod;
FIG. 3 is a schematic diagram of a dual hydraulic cylinder structure according to the present invention;
in the figure: 1. a liquid storage tank; 2. a displacement sensor; 3. a brake pedal; 4. a vacuum booster; 5. a first push rod; 6. a second push rod; 7. a first hydraulic cylinder; 8. a first magnet; 9. a first air chamber; 10. a spring; 11. a second magnet; 12. a first hydraulic chamber; 13. a connecting rod; 14. a second air chamber; 15. a second hydraulic cylinder; 16. a second hydraulic chamber; 17. a ball screw structure; 1701. a ball screw shaft; 1702. a ball bearing; 1703. a ball screw nut; 18. a second hydraulic cylinder piston; 19. a motor; 20. 22 a pressure sensor; 21. 23, 24, 26, 28, 30 normally closed solenoid valves; 25. 27, 29, 31 normally closed solenoid valves; 32. a front left wheel brake; 33 a right front wheel brake; 34. a left rear wheel brake; 35. a right rear wheel brake; 36. and (5) sealing rings.
Detailed Description
In order to facilitate understanding of those skilled in the art, the present invention will be further described with reference to the following examples and drawings, which are not intended to limit the present invention.
Referring to fig. 1, 2 and 3, the double-hydraulic cylinder type brake-by-wire system according to the present invention includes: the brake system comprises a liquid storage tank 1, a displacement sensor 2, a brake pedal 3, a vacuum booster 4, a first push rod 5, a second push rod 6, a first hydraulic cylinder 7, a first magnet 8, a spring 10, a second magnet 11, a connecting rod 13, a second hydraulic cylinder 15, a ball screw structure 17, a second hydraulic cylinder piston 18, a motor 19 and a control unit;
the displacement sensor 2 is used for detecting a braking signal of the brake pedal 3, one end of a first push rod 5 is connected with the brake pedal 3, the other end of the first push rod is connected with the vacuum booster 4, and the first push rod 5 is used for pushing the vacuum booster 4; one end of the second push rod 6 is connected with the vacuum booster 4, and the other end of the second push rod is connected with the first magnet 8; the first magnet 8 and the second magnet 11 are arranged in the first hydraulic cylinder 7, the radial length of the first magnet 8 and the radial length of the second magnet 11 are consistent with that of the hydraulic cylinder, a sealing ring 36 is arranged on the periphery of the first magnet, the second magnet 8 divides the first hydraulic cylinder 7 into two parts, one part is a first air chamber 9, and the other part is a first hydraulic chamber 12; the polarities of the first magnet 8 and the second magnet 11 are the same, a gap is arranged between the first magnet 8 and the second magnet 11 and used for accommodating the spring 10, and two ends of the spring 10 are respectively fixedly connected to the first magnet 8 and the second magnet 11; one end of the connecting rod 13 is fixedly connected to the second magnet 11, and the other end of the connecting rod is fixedly connected to the second hydraulic cylinder piston 18; the ball screw structure 17 includes: the motor comprises a ball screw shaft 1701, balls 1702 and a ball screw nut 1703, wherein the outer side wall of the lower end of the connecting rod 13 is fixedly connected with the ball screw nut 1703, the rotor shaft of the motor 19 is fixedly connected with the ball screw shaft 1701, the balls 1702 are designed in the ball screw structure 17, the ball screw nut 1703 is sleeved on the ball screw shaft 1701, the balls 1702 are positioned between the ball screw nut 1703 and the ball screw shaft 1701, when the motor shaft rotates, the ball screw shaft 1701 is driven to rotate, and the ball screw nut 1703 is driven to translate through the friction effect of the balls 1702;
the second hydraulic cylinder piston 18 is placed in the second hydraulic cylinder 15, the radial diameter of the second hydraulic cylinder piston 18 is consistent with the radial size of the second hydraulic cylinder 15, and the periphery of the second hydraulic cylinder piston is provided with a sealing ring 36 which divides the second hydraulic cylinder 15 into a second air chamber 14 and a second hydraulic chamber 16; the first hydraulic chamber 12 and the second hydraulic chamber 16 are respectively connected with the liquid storage tank 1 through hydraulic pipelines, and the second air chamber 14 is connected with the vacuum booster 4 through an air pipe to provide negative pressure for the vacuum booster 4;
the first hydraulic chamber 12 is respectively connected with a left rear wheel brake 34 and a right rear wheel brake 35 through hydraulic pipelines, and pressure sensors 22 and normally closed electromagnetic valves 23, 28 and 30 are arranged in the pipelines; a normally open electromagnetic valve 29 is arranged in the pipeline of the liquid storage tank and the left rear wheel brake 34, and a normally closed electromagnetic valve 31 is arranged in the pipeline of the liquid storage tank and the right rear wheel brake 35; the second hydraulic chamber 16 is respectively connected with a left front wheel brake 32 and a right front wheel brake 33 through hydraulic pipelines, a pressure sensor 20 and normally closed electromagnetic valves 21, 24 and 26 are arranged in the pipelines, a normally open electromagnetic valve 25 is arranged in the left front wheel brake 32 and a liquid storage tank pipeline, and a normally closed electromagnetic valve 27 is arranged in the right front wheel brake 33 and the liquid storage tank pipeline;
the control unit is connected with the normally open electromagnetic valve, the normally closed electromagnetic valve and the motor circuit through leads and sends control signals to the motor and the electromagnetic valves.
The working principle of the invention is as follows:
1. the electric control system is in a normal braking working condition; before the work is started, an electronic control unit ECU (not marked in the figure) controls the normally open electromagnetic valves 21, 23, 24, 26, 28, 30 to be powered off and opened, the normally closed electromagnetic valves 25, 27, 29, 31 to be powered on and closed, the motor 19 is controlled to start to rotate, the motor output shaft drives the ball screw shaft 1701 to rotate, the ball 1702 in the ball screw structure 17 rolls between the ball screw nut 1703 and the ball screw shaft 1701 to drive the ball screw nut 1703 to move leftwards and further drive the connecting rod 13 to move leftwards, oil in the liquid storage tank 1 flows into the first hydraulic chamber 12 and the second hydraulic chamber 16 through a hydraulic pipeline, the first hydraulic cylinder 7 is divided into the first hydraulic chamber 12 and the first air chamber 9 through the first magnet 8, the second magnet 11 and the sealing ring 36, the second hydraulic cylinder 15 is divided into the second hydraulic chamber 16 and the second air chamber 14 through the second hydraulic cylinder piston 18 and the sealing ring 36, the displacement sensor 2 monitors the displacement signal of the brake pedal 3 in real time and transmits the displacement signal to the electronic control unit ECU, the pressure sensors 20 and 22 detect the oil pressure in the pipeline in real time and transmit the oil pressure signal to the electronic control unit ECU, and when the pressure sensors 20 and 22 detect that the oil pressure in the pipeline is higher than a set threshold value, the motor 19 is controlled to stop working and simultaneously a fault warning signal is sent out.
A driver steps on the brake pedal 3, the brake pedal 3 is connected with the vacuum booster 4 through the first push rod 5, the first push rod 5 moves leftwards under the action of the brake pedal 3, and the second push rod 6 also moves leftwards along with the first push rod 5 under the boosting action of the vacuum booster 4; the right end of the second push rod 6 is connected with the vacuum booster 4, the left end of the second push rod is fixedly connected with the first magnet 8, and the first magnet 8 moves leftwards in the first hydraulic cylinder 7 under the action of the second push rod 6; the polarities of the first magnet 8 and the second magnet 11 are the same, a repulsive force exists, the repulsive force between the first magnet 8 and the second magnet increases with the continuous left movement of the first magnet 8, and the spring 10 (in this example, the spring 10 is a nonlinear spring) is continuously compressed in the left movement of the first magnet 8, and the connecting rod 13 is pushed to move left under the combined action of the spring force and the repulsive force; the displacement sensor 2 detects a brake pedal displacement signal of a driver and transmits the displacement signal to the electronic control unit ECU, the ECU receives the displacement signal and estimates the braking intention of the driver through data processing, the motor 19 is controlled to rotate, the motor 19 drives the ball screw shaft 1701 to rotate, the ball screw shaft 1701 drives the ball screw nut 1703 to move leftwards under the action of the balls 1702, the ball screw nut 1703 drives the connecting rod 13 to translate, the rotary motion of the motor 19 is converted into the linear motion of the connecting rod 13, the second magnet 11 and the second hydraulic cylinder piston 18 respectively drive the connecting rod 13 to move leftwards in the first hydraulic cylinder 7 and the second hydraulic cylinder 15, so that the space in the first air chamber 9 and the second air chamber 14 is increased, the pressure is reduced, vacuum is generated, the second air chamber 14 is connected with the vacuum booster 4 through an air pipe to provide negative pressure required by the vacuum booster, the boosting effect is increased, along with the continuous leftward movement of the second magnet 11 and the second hydraulic cylinder piston 18, the spaces in the first hydraulic chamber 12 and the second hydraulic chamber 16 are continuously reduced, the brake oil is compressed, and the brake oil is changed into high-pressure oil, specifically, the space in the first hydraulic chamber 12 is larger than that in the second hydraulic chamber 16, in the same compression amount process, the oil pressure generated by the second hydraulic chamber 16 is larger than that generated by the first hydraulic chamber 12, and the high-pressure oil in the first hydraulic chamber 12 enters the left rear wheel brake 34 and the right rear wheel brake 35 through the oil pipe, the pressure sensor 22 and the normally open electromagnetic valves 23, 28 and 30 respectively, so as to brake the brakes; the high-pressure oil in the second hydraulic chamber 16 respectively enters a left front wheel brake 32 and a right front wheel brake 33 through an oil pipe, a pressure sensor 20 and normally open electromagnetic valves 21, 24 and 26 to brake the brakes; when the brake is released, the electronic control unit ECU controls the normally open electromagnetic valves 21, 23, 24, 26, 28 and 30 to be electrified and closed, the normally closed electromagnetic valves 25, 27, 29 and 31 to be powered off and opened, and the oil of the four wheel brakes flows back to the liquid storage tank 1 through the normally closed electromagnetic valves 25, 27, 29 and 31.
2. The electric control system is in a failure safety backup working condition;
the motor 19 can not work normally, all the electromagnetic valves of the brake-by-wire system recover the power-off switch state at the moment, specifically, the normally open electromagnetic valves 21, 23, 24, 26, 28 and 30 are opened, the normally closed electromagnetic valves 25, 27, 29 and 31 are closed, the hydraulic pipeline is utilized to flow the oil in the liquid storage tank 1 into the first hydraulic chamber 12 and the second hydraulic chamber 16, and the first hydraulic cylinder 7 is divided into the first hydraulic chamber 12 and the first air chamber 9 through the first magnet 8, the second magnet 11 and the sealing ring 36; the second hydraulic cylinder 15 is divided into a second hydraulic chamber 16 and a second air chamber 14 through a second hydraulic cylinder piston 18 and a sealing ring 36, and the displacement sensor 2 monitors the displacement signal of the brake pedal in real time and transmits the displacement signal to the electronic control unit ECU.
A driver steps on the brake pedal 3, the brake pedal 3 is connected with the vacuum booster 4 through the first push rod 5, the first push rod 5 moves leftwards under the action of the brake pedal 3, and the second push rod 6 also moves leftwards along with the first push rod 5 under the boosting action of the vacuum booster 4; the right end of the second push rod 6 is connected with the vacuum booster 4, the left end of the second push rod is fixedly connected with the first magnet 8, and the first magnet 8 moves leftwards in the first hydraulic cylinder 7 under the action of the second push rod 6; the polarities of the first magnet 8 and the second magnet 11 are the same, repulsive force exists, the repulsive force between the first magnet 8 and the second magnet increases with the continuous left movement of the first magnet 8, and the spring 10 is continuously compressed in the left movement of the first magnet 8, so that the connecting rod 13 is pushed to move towards the left end under the combined action of the spring force and the repulsive force; the displacement sensor 2 detects a displacement signal of a brake pedal stepped by a driver, the displacement signal is transmitted to the electronic control unit ECU, the ECU receives the displacement signal and estimates the braking intention of the driver by data processing, the second magnet 11 and the second hydraulic cylinder piston 18 respectively move to the left in the first hydraulic cylinder 7 and the second hydraulic cylinder 15 under the drive of the connecting rod 13, so that the space in the first air chamber 9 and the second air chamber 14 is increased, the pressure is reduced, vacuum is generated, the second air chamber 14 is connected with the vacuum booster 4 through an air pipe to provide the negative pressure required by the vacuum booster, the boosting effect is increased, the space in the first hydraulic chamber 12 and the second hydraulic cylinder piston 18 is continuously reduced along with the continuous leftward movement of the second magnet 11 and the second hydraulic cylinder piston 18, the braking oil is compressed, the braking oil is changed into high-pressure oil, specifically, the space in the first hydraulic chamber 12 is larger than that in the second hydraulic cylinder piston 16, in the process of the same compression amount, the oil pressure generated by the second hydraulic chamber 16 is greater than that generated by the first hydraulic chamber 12, and the high-pressure oil in the first hydraulic chamber 12 respectively enters the left rear wheel brake 34 and the right rear wheel brake 35 through the oil pipe, the pressure sensor 22 and the normally open electromagnetic valves 23, 28 and 30 to brake the brakes; the high-pressure oil in the second hydraulic chamber 16 respectively enters a left front wheel brake 32 and a right front wheel brake 33 through an oil pipe, a pressure sensor 20 and normally open electromagnetic valves 21, 24 and 26 to brake the brakes, and the traditional hydraulic braking function of the fail-safe backup of the electric control system is completed; when the brake is released, the electronic control unit ECU controls the normally open electromagnetic valves 21, 23, 24, 26, 28 and 30 to be electrified and closed, the normally closed electromagnetic valves 25, 27, 29 and 31 to be powered off and opened, and the oil of the four wheel brakes flows back to the liquid storage tank 1 through the normally closed electromagnetic valves 25, 27, 29 and 31.
3. A brake decoupling process;
a driver steps on the brake pedal 3, the brake pedal 3 is connected with the vacuum booster 4 through the first push rod 5, the first push rod 5 moves leftwards under the action of the brake pedal 3, and the second push rod 6 also moves leftwards along with the first push rod 5 under the boosting action of the vacuum booster 4; the right end of the second push rod 6 is connected with the vacuum booster 4, the left end of the second push rod is fixedly connected with the first magnet 8, and the first magnet 8 moves leftwards in the first hydraulic cylinder 7 under the action of the second push rod 6; the polarities of the first magnet 8 and the second magnet 11 are the same, repulsive force exists, the repulsive force between the first magnet 8 and the second magnet increases along with the continuous left movement of the first magnet 8, in addition, the spring 10 is continuously compressed in the left movement process of the first magnet 8, under the combined action of the spring force and the repulsive force, the connecting rod 13 is pushed to move towards the left end, the second magnet 11 and the second hydraulic cylinder piston 18 respectively move towards the left in the first hydraulic cylinder 7 and the second hydraulic cylinder 15 under the driving of the connecting rod 13, so that the space in the first air chamber 9 and the second air chamber 14 is increased, the pressure is reduced, vacuum is generated, the second air chamber 14 is connected with the vacuum booster 4 through an air pipe, negative pressure required by the vacuum booster 4 is provided, boosting effect is increased, along with the continuous left movement of the second magnet 11 and the second hydraulic cylinder piston 18, the space in the first hydraulic chamber 12 and the second hydraulic chamber 16 is continuously reduced, and compressing the brake oil to change the brake oil into high-pressure oil, wherein the high-pressure oil enters the four wheel brakes for braking through corresponding hydraulic pipelines and electromagnetic valves.
In the whole braking process, although the vacuum booster 4 exists, the repulsive force between the first magnet 8 and the second magnet 11 and the spring force of the spring 10 are used for pushing the second magnet 11 and the second hydraulic cylinder piston 18 to move left to compress the brake oil, and the displacement of the brake pedal has no definite relation with the high-pressure oil amount generated by the first hydraulic chamber 12 and the second hydraulic chamber 16, so that the invention can obtain complete decoupling in the braking process.
In the description of the present invention, it should be noted that the terms "upper", "lower", "left", "right", "inner", "outer", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplification of description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
While the invention has been described in terms of its preferred embodiments, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention.
Claims (5)
1. A double-hydraulic-cylinder type brake-by-wire system is characterized by comprising: the brake system comprises a liquid storage tank, a displacement sensor, a brake pedal, a vacuum booster, a first push rod, a second push rod, a first hydraulic cylinder, a first magnet, a spring, a second magnet, a connecting rod, a second hydraulic cylinder, a ball screw structure, a second hydraulic cylinder piston, a motor and a control unit;
the displacement sensor is used for detecting a braking signal of a brake pedal, one end of the first push rod is connected with the brake pedal, the other end of the first push rod is connected with the vacuum booster, and the first push rod is used for pushing the vacuum booster; one end of the second push rod is connected with the vacuum booster, and the other end of the second push rod is connected with the first magnet; the first magnet and the second magnet are arranged in the first hydraulic cylinder, the radial length of the first magnet and the radial length of the second magnet are consistent with that of the hydraulic cylinder, the periphery of the first magnet and the second magnet is provided with a sealing ring, the first hydraulic cylinder is divided into two parts by the second magnet, one part is a first air chamber, and the other part is a first hydraulic chamber; the first magnet and the second magnet have the same polarity, a gap is formed between the first magnet and the second magnet and used for accommodating the spring, and two ends of the spring are respectively fixedly connected to the first magnet and the second magnet; one end of the connecting rod is fixedly connected to the second magnet, and the other end of the connecting rod is fixedly connected to the second hydraulic cylinder piston; the ball screw structure includes: the outer side wall of the lower end of the connecting rod is fixedly connected with the ball screw nut, a rotor shaft of the motor is fixedly connected with the ball screw shaft, balls are designed in the ball screw structure, the ball screw nut is sleeved on the ball screw shaft, and the balls are located between the ball screw nut and the ball screw shaft;
the second hydraulic cylinder piston is placed in a second hydraulic cylinder, the radial diameter of the second hydraulic cylinder piston is consistent with the radial size of the second hydraulic cylinder, and sealing rings are arranged on the periphery of the second hydraulic cylinder piston and divide the second hydraulic cylinder into a second air chamber and a second hydraulic chamber; the first hydraulic chamber and the second hydraulic chamber are respectively connected with the liquid storage tank through hydraulic pipelines, and the second air chamber is connected with the vacuum booster through an air pipe;
the first hydraulic chamber is respectively connected with the left rear wheel brake and the right rear wheel brake through hydraulic pipelines, and a pressure sensor and a normally closed solenoid valve are arranged in the pipelines; a normally open solenoid valve is arranged in the pipeline of the left rear wheel brake and the liquid storage tank, and a normally closed solenoid valve is arranged in the pipeline of the right rear wheel brake and the liquid storage tank; the second hydraulic chamber is respectively connected with the left front wheel brake and the right front wheel brake through hydraulic pipelines, a pressure sensor and a normally closed solenoid valve are arranged in the pipelines, and a normally open solenoid valve is arranged in the pipelines of the left front wheel brake and the liquid storage tank, and a normally closed solenoid valve is arranged in the pipelines of the right front wheel brake and the liquid storage tank;
the control unit is connected with the normally open electromagnetic valves, the normally closed electromagnetic valves and the motor circuit through conducting wires and sends control signals to the motor, the normally open electromagnetic valves and the normally closed electromagnetic valves.
2. The dual hydraulic cylinder brake-by-wire system of claim 1, wherein the second magnet is a one-piece magnet or a magnet fixed to the outside of the piston.
3. The dual hydraulic cylinder brake-by-wire system according to claim 1, wherein the gap between the first magnet and the second magnet is selected in consideration of matching with the spring characteristics, and an optimal pedal feel is obtained by coordinating the repulsive force of the magnets with the elastic force of the springs.
4. The dual hydraulic cylinder type brake-by-wire system according to claim 1, wherein the second air chamber is a vacuum chamber or is filled with a part of air, and different boosting effects are achieved by connecting with a vacuum booster to generate different air pressure differences.
5. The dual hydraulic cylinder type brake-by-wire system according to claim 1, wherein the first hydraulic chamber and the second hydraulic chamber have different spaces, and the spaces in the first hydraulic chamber and the second hydraulic chamber are continuously reduced by the movement of the second magnet and the second hydraulic cylinder piston, thereby compressing the brake oil and converting the brake oil into high-pressure oil; the method specifically comprises the following steps: the space of the first hydraulic chamber is larger than that of the second hydraulic chamber, and in the same compression process, the oil pressure generated by the second hydraulic chamber is larger than that generated by the first hydraulic chamber, so that different hydraulic braking forces are realized.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110517619.XA CN113246939B (en) | 2021-05-12 | 2021-05-12 | Double-hydraulic-cylinder type line control brake system |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202110517619.XA CN113246939B (en) | 2021-05-12 | 2021-05-12 | Double-hydraulic-cylinder type line control brake system |
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| CN113246939A CN113246939A (en) | 2021-08-13 |
| CN113246939B true CN113246939B (en) | 2022-04-08 |
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| CN202110517619.XA Active CN113246939B (en) | 2021-05-12 | 2021-05-12 | Double-hydraulic-cylinder type line control brake system |
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Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3412351A1 (en) * | 1984-04-03 | 1985-10-10 | Mannesmann Rexroth GmbH, 8770 Lohr | Solenoid valve for controlling the brake pressure in a brake cylinder of a motor vehicle |
| JP2000071957A (en) * | 1998-08-26 | 2000-03-07 | Nissan Motor Co Ltd | Brake control device |
| KR100903509B1 (en) * | 2008-10-20 | 2009-06-17 | 원 배 이 | A control device of brake pressure and method thereof |
| CN102060009B (en) * | 2010-12-10 | 2013-04-17 | 清华大学 | Braking system with electronic braking assisting function |
| CN103640568B (en) * | 2013-12-23 | 2015-10-21 | 吉林东光奥威汽车制动***有限公司 | A kind of can the master brake cylinder of monitors brake pedal position and motion |
| CN104709096B (en) * | 2015-03-27 | 2017-03-01 | 吉林大学 | There is the electric booster braking system of frictional damping and the full decoupled function of regenerative braking |
| CN210971026U (en) * | 2019-11-22 | 2020-07-10 | 吉林大学 | Electromagnetic adjustment type pedal feeling simulation device |
| CN110696795B (en) * | 2019-11-22 | 2023-09-29 | 吉林大学 | Pedal feel simulator based on electromagnetic regulation |
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