CN112406836B - Wire control braking system with backup function and control method thereof - Google Patents
Wire control braking system with backup function and control method thereof Download PDFInfo
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- CN112406836B CN112406836B CN202011454370.4A CN202011454370A CN112406836B CN 112406836 B CN112406836 B CN 112406836B CN 202011454370 A CN202011454370 A CN 202011454370A CN 112406836 B CN112406836 B CN 112406836B
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- 238000000034 method Methods 0.000 title claims abstract description 25
- 239000007788 liquid Substances 0.000 claims abstract description 264
- 230000007246 mechanism Effects 0.000 claims abstract description 22
- 238000003860 storage Methods 0.000 claims abstract description 20
- 238000006073 displacement reaction Methods 0.000 claims description 48
- 230000033001 locomotion Effects 0.000 claims description 43
- 238000005192 partition Methods 0.000 claims description 28
- 239000003921 oil Substances 0.000 claims description 25
- 239000012530 fluid Substances 0.000 claims description 23
- 230000006837 decompression Effects 0.000 claims description 18
- 230000001105 regulatory effect Effects 0.000 claims description 17
- 238000007789 sealing Methods 0.000 claims description 16
- 238000004088 simulation Methods 0.000 claims description 16
- 230000008569 process Effects 0.000 claims description 13
- 239000010727 cylinder oil Substances 0.000 claims description 7
- 230000003068 static effect Effects 0.000 claims description 6
- 230000007423 decrease Effects 0.000 claims description 5
- 238000009434 installation Methods 0.000 claims description 5
- 230000009471 action Effects 0.000 claims description 3
- 230000005540 biological transmission Effects 0.000 claims description 3
- 238000005096 rolling process Methods 0.000 claims description 3
- 230000007704 transition Effects 0.000 claims description 3
- 230000033228 biological regulation Effects 0.000 description 5
- 230000001276 controlling effect Effects 0.000 description 5
- 238000009826 distribution Methods 0.000 description 5
- 230000002457 bidirectional effect Effects 0.000 description 3
- 230000007547 defect Effects 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 2
- 230000036316 preload Effects 0.000 description 2
- 229910000838 Al alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 238000013473 artificial intelligence Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 238000011946 reduction process Methods 0.000 description 1
- 230000001172 regenerating effect Effects 0.000 description 1
Classifications
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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
- B60T13/142—Systems with master cylinder
- B60T13/147—In combination with distributor valve
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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
- B60T13/68—Electrical control in fluid-pressure brake systems by electrically-controlled valves
- B60T13/686—Electrical control in fluid-pressure brake systems by electrically-controlled valves in hydraulic systems or parts thereof
-
- 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
- B60T13/74—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 electrical assistance or drive
- B60T13/746—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 electrical assistance or drive and mechanical transmission of the braking action
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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
- B60T7/00—Brake-action initiating means
- B60T7/02—Brake-action initiating means for personal initiation
- B60T7/04—Brake-action initiating means for personal initiation foot actuated
- B60T7/042—Brake-action initiating means for personal initiation foot actuated by electrical means, e.g. using travel or force sensors
-
- 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
- B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
- B60T8/32—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration
- B60T8/34—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration having a fluid pressure regulator responsive to a speed condition
- B60T8/40—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration having a fluid pressure regulator responsive to a speed condition comprising an additional fluid circuit including fluid pressurising means for modifying the pressure of the braking fluid, e.g. including wheel driven pumps for detecting a speed condition, or pumps which are controlled by means independent of the braking system
- B60T8/4072—Systems in which a driver input signal is used as a control signal for the additional fluid circuit which is normally used for braking
- B60T8/4081—Systems with stroke simulating devices for driver input
- B60T8/409—Systems with stroke simulating devices for driver input characterised by details of the stroke simulating device
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- Engineering & Computer Science (AREA)
- Transportation (AREA)
- Mechanical Engineering (AREA)
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- Regulating Braking Force (AREA)
Abstract
The invention discloses a brake-by-wire system with a backup function and a control method thereof, wherein the brake-by-wire system comprises a brake control mechanism, an active brake pedal stroke simulator, a main energy supply device and a hydraulic adjusting unit; a liquid outlet A, a liquid outlet B and a liquid inlet C of a first chamber and a liquid outlet C of a second chamber of a brake master cylinder in the brake control mechanism are respectively connected with a liquid inlet D, a liquid inlet E and a liquid outlet F of an active brake pedal stroke simulator, a liquid outlet G and a liquid outlet H of the active brake pedal stroke simulator are respectively connected with a liquid inlet M and a liquid inlet L of a hydraulic control unit through pipelines, a liquid outlet I and a liquid outlet J of a main energy supply device are respectively connected with a liquid inlet M and a liquid inlet L of the hydraulic control unit through pipelines, and a liquid inlet K of the main energy supply device and a liquid outlet R of the hydraulic control unit are both connected with a liquid outlet D of a liquid storage tank in the brake control mechanism through pipelines. The invention also provides a control method of the brake-by-wire system with the backup function.
Description
Technical Field
The invention relates to a brake-by-wire system applied to the field of automobile brake systems, in particular to a brake-by-wire system with a backup function and a control method thereof.
Background
In recent years, with the progress of artificial intelligence technology, it has become possible to use a robot instead of a human to complete driving tasks, and unmanned vehicles tend to become one of the development trends of future automobile technologies, and intelligent driving systems eventually replace human to drive automobiles. The advent of intelligent driving systems has put forward new and higher demands on braking systems, and newly introduced intelligent driving functions require that the braking systems can realize brake-by-wire through instructions, and the braking systems are guaranteed to have higher availability, and all key functions including brake-by-wire have redundant backups, and are not limited to traditional conventional brake mechanical backups. To meet these needs, the brake-by-wire system should have a redundant backup function, a higher pressure regulating capability, and a pedal stroke simulation function, so that the brake pedal of the brake-by-wire system still has a pedal feel similar to that of a conventional brake pedal.
Several patent applications are searched for that are relevant to the present invention:
chinese patent publication No. CN109552287a, publication date 2019.04.02, entitled "brake-by-wire system and vehicle", application No. 201710885196.0. The brake system actuating mechanism designed by the invention comprises two electric brakes and two hydraulic brakes which are respectively controlled by a motor and a hydraulic unit and are respectively applied to a front shaft and a rear shaft. The disadvantage of the invention is that the brake-by-wire system lacks redundancy backup.
Chinese patent publication No. CN109606340a, publication date 2019.04.12, entitled "electromechanical brake System with backup brake System", application No. 201811553147.8. The design of the invention provides an electronic brake system which uses hydraulic pressure to simulate pedal feel, uses electronic brake as a main braking mode and simultaneously keeps a hydraulic pipeline as a backup unit. The invention has the defects that the reaction of the backup braking system is not sensitive enough, the implementation is difficult, the braking capability is limited, the structure of the actuating mechanism of the electronic braking system is complex, the control difficulty is large, and the four wheels all adopt repeated actuating mechanisms, thereby greatly improving the cost of the braking system.
Chinese patent publication No. CN110525409a, publication date 2019.12.03, entitled "redundant service brake System for vehicle", application No. 201910753378.1. The invention adopts the motor hydraulic pump as the power source of the backup braking system, and realizes the mode switching between the main braking system and the backup braking system through the electromagnetic valve. The invention has the defects that the electromagnetic valves which need to be controlled are more, the performance requirement of the backup braking system on the motor hydraulic pump is too high, and the capacity of the backup braking system is exceeded.
Disclosure of Invention
The invention aims to solve the technical problems that the performance requirement of a brake-by-wire system exceeds the capability of the existing product, the structure is complex, the control difficulty is high, the braking capability of a redundant backup system is limited, and the pedal feel is inconsistent with that of the traditional vehicle in the prior art, and provides the brake-by-wire system with the backup function and the control method thereof.
In order to solve the technical problems, the invention is realized by adopting the following technical scheme:
the brake-by-wire system with the backup function comprises a brake operating mechanism, an active brake pedal stroke simulator, a main energy supply device and a hydraulic adjusting unit;
the brake control mechanism comprises a brake master cylinder and a liquid storage tank; the brake master cylinder is internally provided with three chambers which are arranged in series, and a first chamber, a second chamber and a third chamber are sequentially arranged from left to right;
the first chamber liquid outlet A of the brake master cylinder is connected with a liquid inlet D brake pipeline of the active brake pedal stroke simulator, the second chamber liquid outlet B of the brake master cylinder is connected with a liquid inlet E brake pipeline of the active brake pedal stroke simulator, the third chamber liquid inlet C of the brake master cylinder is connected with a liquid outlet F brake pipeline of the active brake pedal stroke simulator, the liquid outlet G of the active brake pedal stroke simulator and the liquid outlet I of the main energy supply device are connected with a liquid inlet M brake pipeline of the hydraulic pressure regulating unit, the liquid outlet H of the active brake pedal stroke simulator and the liquid outlet J of the main energy supply device are connected with a liquid inlet L brake pipeline of the hydraulic pressure regulating unit, and the liquid inlet K of the main energy supply device and the liquid outlet R of the hydraulic pressure regulating unit are connected with a liquid outlet D brake pipeline of the liquid storage tank.
The technical scheme includes that the brake master cylinder comprises a brake master cylinder body, a brake master cylinder first piston, a brake master cylinder second piston, a brake master cylinder first piston spring, a brake master cylinder second piston spring and a brake master cylinder push rod; the brake master cylinder body is a cylindrical structural member, the left end of the brake master cylinder body is closed, the right end of the brake master cylinder body is opened, a flange is arranged on the right end face of the brake master cylinder body, six liquid inlets and outlets are arranged on the outer cylindrical surface of the brake master cylinder body, and the six liquid inlets and the six liquid outlets are threaded holes; the first piston spring of the brake master cylinder, the first piston of the brake master cylinder, the second piston spring of the brake master cylinder, the second piston of the brake master cylinder and the push rod of the brake master cylinder are sequentially arranged in the cylinder body of the brake master cylinder, the first piston of the brake master cylinder, the second piston of the brake master cylinder and the cylinder body of the brake master cylinder are in sliding connection, and the rotation axes of the first piston spring of the brake master cylinder, the first piston of the brake master cylinder, the second piston spring of the brake master cylinder, the second piston of the brake master cylinder, the push rod of the brake master cylinder and the cylinder body of the brake master cylinder are collinear; the inside of the brake master cylinder is provided with three chambers which are isolated by a first piston of the brake master cylinder and a second piston of the brake master cylinder and can generate high-pressure brake fluid independently of each other, the three chambers are arranged in series, a first chamber, a second chamber and a third chamber are sequentially arranged from left to right, and a mechanical inlet of the brake master cylinder is a brake master cylinder push rod; the brake master cylinder is fixed on the vehicle body through a flange plate.
The liquid storage tank in the technical scheme is provided with four liquid outlets, namely a liquid outlet f, a liquid outlet r, a liquid outlet t and a liquid outlet d, wherein the liquid outlet f, the liquid outlet r and the liquid outlet t are respectively connected with a liquid inlet a of a first chamber of the brake master cylinder, a liquid inlet b of a second chamber of the brake master cylinder and a liquid inlet c of a third chamber of the brake master cylinder through pipelines, and the liquid storage tank is arranged above the brake master cylinder.
The brake control mechanism in the technical scheme also comprises a brake pedal, a pedal displacement sensor and a brake master cylinder check valve; the brake pedal is arranged below the front part of a driver in a carriage, the top end of a rotating part in the brake pedal is fixed on a pedal bracket through a pin shaft, the pedal bracket is fixed on a vehicle body through a bolt, the left side surface of the middle end of the rotating part in the brake pedal is in contact connection with the right end surface of a push rod of a brake master cylinder in a brake master cylinder, a pedal displacement sensor is fixed on the pedal bracket connected with the vehicle body, a movable arm of the pedal displacement sensor is connected with the rotating part in the brake pedal, a brake master cylinder check valve is arranged between a liquid outlet t of a liquid storage tank and a liquid inlet c of a third chamber of the brake master cylinder, a p port of the brake master cylinder check valve is connected with a liquid outlet t of the liquid storage tank through a hydraulic pipeline, and an a port a of the brake master cylinder check valve is connected with the liquid inlet c of the third chamber of the brake master cylinder through a hydraulic pipeline.
The active brake pedal travel simulator comprises a motor controller a motor, a driving gear, a toothed internal circulation nut, a ball, a screw mandrel limit switch, back cover, baffle, first thrust bearing, second piston spring, second piston sealing ring, first piston the brake master cylinder comprises a first piston spring, a third piston spring seat retainer ring, a third piston sealing ring, a simulator cylinder body, a simulator one-way valve, a simulator third liquid outlet electromagnetic valve, a simulator first liquid outlet electromagnetic valve, a simulator second liquid outlet electromagnetic valve and a brake master cylinder pressure sensor;
the simulator cylinder body is a cylindrical structural member, the left end and the right end of the simulator cylinder body are both open, a flange plate for installation is arranged on the outer cylindrical surface of the left end cylinder opening, three bolt holes are uniformly distributed on the flange plate, three-section cylindrical stepped holes are processed along the central axis of the simulator cylinder body, the diameters of the three-section stepped holes decrease from left to right in sequence, the three-section stepped holes are a first section stepped hole, a second section stepped hole and a third section stepped hole in sequence, a second piston and a second piston spring are installed in the first section stepped hole, the first piston and the first piston spring are installed in the second section stepped hole, the third section stepped hole is an oil inlet and outlet hole of the simulator cylinder body, an internal threaded hole is processed in the cylindrical wall of the first section stepped hole, the three-section cylindrical stepped holes are communicated with each other, and the rotation axes are collinear;
The third piston is a two-section stepped shaft, the diameter of the right end shaft is larger, an annular groove for placing a sealing ring is formed in the cylindrical surface of the right end shaft, the diameter of the left end shaft is smaller and is used for installing a third piston spring, a circular groove for placing a retainer ring of a third piston spring seat is formed in the cylindrical surface of the left end shaft, a circular hole is formed in the left end shaft along the rotation center line of the stepped shaft, and the diameter of the hole is slightly larger than that of a right end sliding rod of the screw mandrel; the first piston is a two-section stepped shaft, the right end shaft diameter is larger, the left end shaft diameter is smaller, the left end shaft diameter is used for installing a third piston spring, a circular boss is arranged on the left end face of the shaft with larger diameter and used for installing the first piston spring, a circular stepped hole is machined along the rotation center line of the stepped shaft, the diameter of the right end of the stepped hole is larger and is equal to that of the right end of the third piston, and the diameter of the left end of the stepped hole is smaller and is equal to that of the left end of the third piston; the second piston is a two-section stepped shaft, the diameter of the right end shaft is larger, a circular boss is arranged on the right end face and is used for installing the first piston spring, an annular groove for placing a sealing ring is formed in the cylindrical surface of the right end shaft, the diameter of the left end shaft is smaller and is used for installing the second piston spring, a circular through hole is formed along the rotation center line of the stepped shaft, and the diameter of the through hole is slightly larger than that of the left end shaft of the first piston;
The simulator cylinder body is arranged on the right end face of the partition board through a bolt, the rear cover is arranged on the left end face of the partition board through a rivet, the toothed internal circulation nut is arranged between the rear cover and the partition board through a first thrust bearing and a second thrust bearing, the left end face and the right end face of the first thrust bearing are respectively in contact connection with the rear cover and the toothed internal circulation nut, the left end face and the right end face of the second thrust bearing are respectively in contact connection with the toothed internal circulation nut and the partition board, the left end rollaway of the screw rod mandril is arranged in a spiral rollaway connection with the center hole of the toothed internal circulation nut through balls, the right end of the screw rod mandril is inserted into a stepped hole of the simulator cylinder body, the right end of the screw rod mandril is sleeved with a third piston, the left end of the third piston is sleeved in the second piston, the right end of the third piston is sleeved in the first piston for sliding connection, the first piston and the second piston are sequentially arranged in a first section of stepped hole and a second section of stepped hole of the simulator cylinder body for sliding connection, the first piston spring is sleeved on a circular boss on a second end face on the left side of the first piston, the second piston spring and the third piston spring are respectively arranged on a left end shaft of the second piston and a left end shaft of the third piston, the third piston spring seat is sleeved on the left end of the third piston for transition fit, the third piston spring seat retainer ring is arranged in a circular groove on the left end of the third piston, the left end face of the third piston spring seat is in contact connection with the right end face of the third piston spring seat retainer ring, the second piston seal ring and the third piston seal ring are respectively sleeved in annular grooves of the second piston and the third piston, the motor is arranged on the right end face of a partition plate below the simulator cylinder body, the driving gear is sleeved on an output shaft of the motor for interference fit connection, the driving gear is in meshed connection with the toothed internal circulation nut, the motor controller is arranged on the right end face of the motor shell, the motor is connected with the motor controller through a wire, the limit switch is arranged at the center of the rear cover, the limit switch is connected with the motor controller through a limit switch signal wire, an a port of the simulator electromagnetic valve, a p port of the simulator third liquid outlet electromagnetic valve and an a port of the simulator check valve are all connected with an oil inlet and outlet hole hydraulic pipeline on the simulator cylinder body, a p port of the simulator electromagnetic valve and a p port of the simulator first liquid outlet electromagnetic valve are all connected with a D port hydraulic pipeline of the active brake pedal stroke simulator, an a port of the simulator first liquid outlet electromagnetic valve is connected with a G port hydraulic pipeline of the active brake pedal stroke simulator, a p port of the simulator second liquid outlet electromagnetic valve and a brake master cylinder pressure sensor are all connected with an E port hydraulic pipeline of the active brake pedal stroke simulator, and an a port of the simulator third liquid outlet electromagnetic valve and a port of the simulator check valve are all connected with an F port hydraulic pipeline of the active brake pedal stroke simulator.
The main energy supply device comprises an electric hydraulic cylinder, an electric hydraulic cylinder pressure sensor, a first liquid outlet electromagnetic valve of the electric hydraulic cylinder and a second liquid outlet electromagnetic valve of the electric hydraulic cylinder;
the electric hydraulic cylinder comprises an electric hydraulic cylinder body, an electric hydraulic cylinder piston spring, an electric hydraulic cylinder piston, an electric hydraulic cylinder ball screw and an electric hydraulic cylinder motor; the electric hydraulic cylinder body is a cylindrical structural member, the left end and the right end of the electric hydraulic cylinder body are provided with holes, the left end of each hole is provided with a smaller diameter and is processed into a threaded hole, the hole is an electric hydraulic cylinder oil inlet and outlet hole a, the right end of each hole is provided with a larger diameter, and an oil inlet and outlet hole p is formed in the outer cylindrical surface of the electric hydraulic cylinder body; the center of the right end of the electric hydraulic cylinder piston is provided with a center hole, the inner cylindrical surface of the center hole is provided with a spiral rollaway nest for mounting balls, and the electric hydraulic cylinder ball screw is provided with a spiral rollaway nest matched with the spiral rollaway nest of the electric hydraulic cylinder piston; the electric hydraulic cylinder piston spring and the electric hydraulic cylinder piston are sequentially arranged in the electric hydraulic cylinder body, the electric hydraulic cylinder piston is in sliding connection with the electric hydraulic cylinder body, the left end of the electric hydraulic cylinder ball screw is arranged in a central hole at the right end of the electric hydraulic cylinder piston and is in rolling connection, the right end of the electric hydraulic cylinder ball screw is connected with the electric hydraulic cylinder motor through a transmission mechanism, and the electric hydraulic cylinder ball screw can convert the rotary motion of the electric hydraulic cylinder motor into the linear motion of the electric hydraulic cylinder piston;
The p port of the first liquid outlet electromagnetic valve of the electric hydraulic cylinder, the p port of the second liquid outlet electromagnetic valve of the electric hydraulic cylinder and the pressure sensor of the electric hydraulic cylinder are all connected with an oil inlet and outlet hole a hydraulic pipeline of the electric hydraulic cylinder, the a port of the first liquid outlet electromagnetic valve of the electric hydraulic cylinder is connected with an I port hydraulic pipeline of the main energy supply device, the a port of the second liquid outlet electromagnetic valve of the electric hydraulic cylinder is connected with a J port hydraulic pipeline of the main energy supply device, and the oil inlet and outlet hole p of the electric hydraulic cylinder is connected with a K port hydraulic pipeline of the main energy supply device.
The hydraulic adjusting unit comprises a right rear wheel one-way valve, a right rear wheel liquid inlet electromagnetic valve, a left front wheel one-way valve, a left front wheel liquid inlet electromagnetic valve, a right front wheel one-way valve, a right front wheel liquid inlet electromagnetic valve, a left rear wheel one-way valve, a left rear wheel liquid inlet electromagnetic valve, a right rear wheel liquid outlet electromagnetic valve, a left front wheel liquid outlet electromagnetic valve, a right front wheel liquid outlet electromagnetic valve and a left rear wheel liquid outlet electromagnetic valve;
the hydraulic control system is characterized in that an a port of a right rear wheel one-way valve, a P port of a right rear wheel liquid inlet electromagnetic valve, an a port of a left front wheel one-way valve and a P port of a left front wheel liquid inlet electromagnetic valve are all connected with an M port hydraulic pipeline of a hydraulic control unit, an a port of a right front wheel one-way valve, an a port of a left rear wheel one-way valve and a P port of a left rear wheel liquid inlet electromagnetic valve are all connected with an L port hydraulic pipeline of the hydraulic control unit, an a port of a right rear wheel one-way valve, an a port of a right rear wheel liquid inlet electromagnetic valve and a P port of a right rear wheel liquid outlet electromagnetic valve are all connected with a Q port hydraulic pipeline of the hydraulic control unit, an a port of a left front wheel one-way valve, an a port of a left front wheel liquid outlet electromagnetic valve and a P port of a left front wheel liquid outlet electromagnetic valve are all connected with an O port hydraulic pipeline of the hydraulic control unit, and an N port of a left rear wheel one-way valve and a left rear wheel liquid outlet electromagnetic valve are all connected with an A port of the hydraulic control unit.
The control method of the brake-by-wire system with the backup function comprises the following steps:
1) Detecting whether the displacement of a brake pedal is 0, receiving a pedal displacement signal transmitted by a pedal displacement sensor by a brake controller, and entering a step 2 if the pedal displacement is 0; otherwise, entering step 3);
2) When the pedal displacement is 0, a working state instruction sent to a motor controller of the simulator by the brake controller is in an idle state, so that the active brake pedal stroke simulator is in the idle state, when the screw rod ejector rod is in an initial position, the motor does not work, when the screw rod ejector rod is not in the initial position, the motor controller drives the motor to reversely rotate, the motor converts the rotary motion of the motor into the linear motion of the screw rod ejector rod through a driving gear, a toothed internal circulation nut, a ball and the screw rod ejector rod, the screw rod ejector rod moves leftwards until the left end of a sliding rod of the screw rod ejector rod contacts with a limit switch, and the limit switch transmits acquired signals to the motor controller through a limit switch signal wire, so that the screw rod ejector rod is considered to be in the initial position; meanwhile, the main energy supply device is also in an idle state, when the electric hydraulic cylinder piston is in an initial position, the electric hydraulic cylinder motor does not work, when the electric hydraulic cylinder piston is not in the initial position, the electric hydraulic cylinder motor is driven to reversely rotate, the electric hydraulic cylinder motor converts rotary motion into linear motion of the electric hydraulic cylinder piston through an electric hydraulic cylinder ball screw, the electric hydraulic cylinder piston moves rightwards to the initial position, whether the electric hydraulic cylinder piston returns or not is judged through the rotating speed of the electric hydraulic cylinder motor, and when the rotating speed of the electric hydraulic cylinder motor is lower than a threshold value w, the electric hydraulic cylinder piston is considered to return, and the threshold value w is required to be obtained through test calibration; when the pedal displacement is 0 and the screw rod ejector rod in the active brake pedal stroke simulator and the electric hydraulic cylinder piston in the main energy supply device are all reset, the brake system does not work;
3) When the pedal displacement is greater than 0, a target master cylinder pressure P is calculated Master cylinder tar The brake controller receives pedal displacement signals transmitted by a pedal displacement sensor, and obtains target master cylinder pressure P under corresponding pedal displacement according to a relation curve of traditional automobile pedal displacement and master cylinder pressure measured by a test Master cylinder tar ；
4) The brake controller sends a working state instruction to the simulator motor controller to be in a pedal stroke simulation state, so that the active brake pedal stroke simulator is in the pedal stroke simulation state, when the screw rod ejector rod is in an initial position, the motor does not work, and when the screw rod ejector rod is not in the initial position, the motor controller drives the motor to reversely rotate, so that the screw rod ejector rod is operated to the initial position; after that, the electromagnetic valve of the simulator is opened, the first liquid outlet electromagnetic valve of the simulator, the second liquid outlet electromagnetic valve of the simulator and the third liquid outlet electromagnetic valve of the simulator are all closed, and all front axle brake liquid enters the active brake pedal stroke simulator, and pedal feel is completely provided by the brake pedal stroke simulator; in order to make the pedal feel consistent with the traditional brake pedal feel, the parameters of a first piston spring, a second piston spring, a first piston and a second piston of an active brake pedal stroke simulator are required to be matched, so that the brake pedal stroke simulator can accurately simulate the pressure volume characteristic of a wheel cylinder, and the pedal feel is ensured; the first liquid outlet electromagnetic valve of the electric hydraulic cylinder and the second liquid outlet electromagnetic valve of the electric hydraulic cylinder are opened, and at the moment, the wheel cylinder pressure is provided by the main energy supply device;
5) The brake controller receives a main energy supply device pressure signal P transmitted by an electric hydraulic cylinder pressure sensor Electro-hydraulic cylinder act The method comprises the steps of carrying out a first treatment on the surface of the If the main power supply device pressure signal P Electro-hydraulic cylinder act Less than the target master cylinder pressure P Master cylinder tar Step 6) is entered; if the main power supply device pressure signal P Electro-hydraulic cylinder act Equal to the target master cylinder pressure P Master cylinder tar Step 7) is entered; otherwise, enter step 8);
6) Pressure signal P of main energy supply device Electro-hydraulic cylinder act Less than the target master cylinder pressure P Master cylinder tar When the electric hydraulic cylinder piston moves to the oil inlet and outlet hole p of the electric hydraulic cylinder, the main energy supply device starts to build pressure and the actual pressure gradually rises;
7) Pressure signal P of main energy supply device Electro-hydraulic cylinder act Equal to the target master cylinder pressure P Master cylinder tar When the main energy supply device is in a pressure maintaining state, the electric hydraulic cylinder motor is static, and the ball screw of the electric hydraulic cylinder and the piston of the electric hydraulic cylinder keep the original position and do not move, so that the actual pressure of the main energy supply device is kept unchanged;
8) Pressure signal P of main energy supply device Electro-hydraulic cylinder act Greater than target master cylinder pressure P Master cylinder tar When the main energy supply device is in a decompression state, the electric hydraulic cylinder motor is driven to reversely rotate, the electric hydraulic cylinder motor converts rotary motion into linear motion of the electric hydraulic cylinder piston through the electric hydraulic cylinder ball screw, the electric hydraulic cylinder piston moves rightwards, the actual pressure of the main energy supply device is gradually reduced, and when the electric hydraulic cylinder piston returns to the electric hydraulic cylinder, the main energy supply device is driven to reversely rotateAfter the oil inlet and outlet hole p is formed, the actual pressure of the main energy supply device is reduced to 0, and after the electric hydraulic cylinder piston returns, the decompression process is finished;
9) The brake controller receives the pressure signal P of the main energy supply device transmitted by the pressure sensor of the electric hydraulic cylinder again Electro-hydraulic cylinder act Judging whether the main energy supply device fails, if so, entering step 10), otherwise, returning to step 1);
10 The first liquid outlet electromagnetic valve of the electric hydraulic cylinder and the second liquid outlet electromagnetic valve of the electric hydraulic cylinder are closed, the simulator electromagnetic valve is closed, the first liquid outlet electromagnetic valve of the simulator, the second liquid outlet electromagnetic valve of the simulator and the third liquid outlet electromagnetic valve of the simulator are opened, and at the moment, the wheel cylinder pressure is completely provided by the brake master cylinder;
11 Brake controller receives a brake master cylinder pressure signal P transmitted by a brake master cylinder pressure sensor Brake master cylinder act The method comprises the steps of carrying out a first treatment on the surface of the If the master cylinder pressure signal P Brake master cylinder act Less than the target master cylinder pressure P Master cylinder tar Step 12) is entered; if the master cylinder pressure signal P Brake master cylinder act Equal to the target master cylinder pressure P Master cylinder tar Step 13) is entered; otherwise, go to step 14);
12 Brake master cylinder pressure signal P Brake master cylinder act Less than the target master cylinder pressure P Master cylinder tar When the screw rod ejector rod moves to be in contact with the third piston, the third piston starts to move rightwards relative to the first piston, the pressurizing process starts, the third piston is continuously pushed along with the screw rod ejector rod, and the pressurizing process is continuously carried out; brake fluid enters a third chamber of the brake master cylinder through an oil inlet and outlet hole of the simulator and a third liquid outlet electromagnetic valve of the simulator, and the active pressurization and pedal feel simulation work is completed by adjusting the active brake pedal travel simulator in real time, so that the actual pressure of the brake master cylinder is gradually increased;
13 Brake master cylinder pressure signal P Brake master cylinder act Equal to the target master cylinder pressure P Master cylinder tar When the brake controller sends a working state instruction to the simulator motor controller to be in a pressure maintaining state, so that the active brake pedal stroke simulator is in the pressure maintaining state, the motor controller sends a control instruction to enable the motor to be static, and the screw mandrel and the third piston keep the original position unchanged, so that the actual pressure of the brake master cylinder is kept unchanged;
14 Brake master cylinder pressure signal P Brake master cylinder act Greater than target master cylinder pressure P Master cylinder tar When the brake controller sends a working state instruction to the simulator motor controller to be in a decompression state, so that the active brake pedal stroke simulator is in a decompression state, the motor controller sends a control instruction to enable the motor to reversely rotate, the motor converts rotary motion into linear motion of the screw rod ejector rod through a driving gear, a toothed internal circulation nut, a ball and the screw rod ejector rod until the screw rod ejector rod moves to be in contact with a limit switch, the screw rod ejector rod returns to an initial position, a third piston moves leftwards relative to a first piston under the action of a third piston spring and high-pressure brake fluid until the third piston returns, brake fluid in a third chamber of a brake master cylinder flows back to the active brake pedal stroke simulator through a simulator one-way valve and a simulator oil inlet and outlet hole, active decompression and pedal feel simulation work is completed through real-time adjustment of the active brake pedal stroke simulator, and the actual pressure of the brake master cylinder gradually decreases until the decompression process is finished;
15 Returning to step 1).
Compared with the prior art, the invention has the beneficial effects that:
1. the brake-by-wire system with the backup function has a simple hardware structure, only an active brake pedal stroke simulator is needed to be additionally arranged on the basis of the brake-by-wire system, and only a small amount of electromagnetic valves and the active brake pedal stroke simulator are needed to be controlled in the conventional braking process and the redundant backup braking process, so that the control difficulty is low.
2. The active brake pedal stroke simulator in the brake-by-wire system with the backup function integrates pedal feel simulation function and pressure regulation function integrated with active pressurization and pressure maintaining and active depressurization, and overcomes the defect of the pressure regulation capability of the traditional hydraulic regulation unit.
3. The brake-by-wire system with the backup function can simulate pedal feel through the active brake pedal travel simulator when the main energy supply device works, and can dynamically regulate the brake master cylinder pressure and pedal feel through the active pressure regulating function of the active brake pedal travel simulator after the main energy supply device fails, so that the redundant backup design of the brake system is realized while the brake pedal feel is consistent with that of a traditional automobile, and the driving safety is guaranteed to the greatest extent.
4. The brake-by-wire system with the backup function can be installed in a hybrid electric vehicle and an electric vehicle, hydraulic braking and motor braking can be better matched through accurate braking pressure adjustment, the regenerative braking capacity of the motor can be exerted to the greatest extent, and the warp of the hybrid electric vehicle and the electric vehicle is greatly improved.
Drawings
The invention is further described below with reference to the accompanying drawings:
FIG. 1 is a schematic diagram of a brake-by-wire system architecture with backup according to the present invention;
FIG. 2 is a schematic illustration of the structural components of an active brake pedal travel simulator in a brake-by-wire system with backup function in accordance with the present invention;
FIG. 3 is a right side view of a simulator body of an active brake pedal travel simulator in a brake-by-wire system with backup function in accordance with the present invention;
FIG. 4 is a schematic diagram of a main power supply device structure in a brake-by-wire system with backup function according to the present invention;
FIG. 5 is a schematic diagram of the structural components of a hydraulic regulator unit in a brake-by-wire system with backup according to the present invention;
FIG. 6 is a flow chart of a control method of a brake-by-wire system with backup function according to the present invention;
In the figure: 1. a brake operating mechanism, 2, a reservoir, 3, a brake master cylinder one-way valve, 4, a brake master cylinder push rod, 5, a pedal displacement sensor, 6, a brake pedal, 7, a brake master cylinder, 8, a brake master cylinder second piston, 9, a brake master cylinder second piston spring, 10, a brake master cylinder first piston, 11, a brake master cylinder first piston spring, 12, an active brake pedal travel simulator, 13, a master energy device, 14, a hydraulic adjustment unit, 15, a right rear wheel, 16, a left front wheel, 17, a right front wheel, 18, a left rear wheel, 19, a toothed internal circulation nut, 20, a second thrust bearing, 21, a first thrust bearing, 22, a limit switch, 23, a lead screw push rod, 24, balls, 25, a drive gear, 26, a limit switch signal line, 27, a first motor fixing bolt, 28, a motor, 29, a motor controller, 30, a second piston seal ring, A simulator cylinder 32, a third piston seal 33, an oil inlet and outlet hole 34, a first piston 35, a third piston 36, a first piston spring 37, a third piston spring 38, a third piston spring seat 39, a third piston spring seat retainer ring 40, a second piston 41, a second piston spring 42, a vent hole 43, a second bulkhead connecting bolt 44, a bulkhead 45, a fourth rear cover connecting rivet 46, a rear cover 47, a simulator one-way valve 48, a simulator third liquid outlet solenoid valve 49, a simulator solenoid valve 50, a simulator first liquid outlet solenoid valve 51, a simulator second liquid outlet solenoid valve 52, a brake master cylinder pressure sensor 53, a second motor fixing bolt 54, a seventh rear cover connecting rivet 55, a third bulkhead connecting bolt 56, a sixth rear cover connecting rivet 57, a fifth rear cover connecting rivet, 58. the third rear cover is attached to the rivet 59, the second rear cover is attached to the rivet 60, the first bulkhead is attached to the bolt 61, the first rear cover is attached to the rivet 62, the electro-hydraulic cylinder pressure sensor 63, the electro-hydraulic cylinder first outlet solenoid valve 64, the electro-hydraulic cylinder second outlet solenoid valve 65, the electro-hydraulic cylinder body 66, the electro-hydraulic cylinder piston spring 67, the electro-hydraulic cylinder piston 68, the electro-hydraulic cylinder ball screw 69, the electro-hydraulic cylinder motor 70, the right rear wheel check valve 71, the right rear wheel inlet solenoid valve 72, the left front wheel check valve 73, the left front wheel inlet solenoid valve 74, the right front wheel check valve 75, the right front wheel inlet solenoid valve 76, the left rear wheel check valve 77, the left rear wheel inlet solenoid valve 78, the right rear wheel outlet solenoid valve 79, the left front wheel outlet solenoid valve 80, the right front wheel outlet solenoid valve 81.
Detailed Description
The invention is described in detail below with reference to the attached drawing figures:
the brake-by-wire system with the backup function comprises a brake operating mechanism 1, an active brake pedal stroke simulator 12, a main energy supply device 13 and a hydraulic adjusting unit 14.
Referring to fig. 1, the brake operating mechanism 1 comprises a brake master cylinder, a liquid storage tank 2, a brake pedal 6, a pedal displacement sensor 5 and a brake master cylinder check valve 3.
The brake master cylinder comprises a brake master cylinder body 7, a brake master cylinder first piston 10, a brake master cylinder second piston 8, a brake master cylinder first piston spring 11, a brake master cylinder second piston spring 9 and a brake master cylinder push rod 4; the brake master cylinder body 7 is a cylindrical structural member, the left end of the brake master cylinder body is closed, the right end of the brake master cylinder body is opened, a flange is arranged on the right end face of the brake master cylinder body, six liquid inlets and outlets are arranged on the outer cylindrical surface of the brake master cylinder body 7, and the six liquid inlets and the six liquid outlets are threaded holes; the brake master cylinder first piston spring 11, the brake master cylinder first piston 10, the brake master cylinder second piston spring 9, the brake master cylinder second piston 8 and the brake master cylinder push rod 4 are sequentially arranged in the brake master cylinder body 7, the brake master cylinder first piston 10, the brake master cylinder second piston 8 and the brake master cylinder body 7 are in sliding connection, and the rotation axes of the brake master cylinder first piston spring 11, the brake master cylinder first piston 10, the brake master cylinder second piston spring 9, the brake master cylinder second piston 8, the brake master cylinder push rod 4 and the brake master cylinder body 7 are collinear; the brake master cylinder is internally provided with three chambers which are isolated by a brake master cylinder first piston 10 and a brake master cylinder second piston 8 and can generate high-pressure brake fluid independently, the three chambers are arranged in series, the chambers are a first chamber, a second chamber and a third chamber in sequence from left to right, a mechanical inlet of the brake master cylinder is a brake master cylinder push rod 4, and mechanical energy input by a pedal of a driver can be converted into hydraulic energy.
The liquid storage tank 2 generally uses the rigid plastic material, totally four liquid outlets are respectively a liquid outlet f, a liquid outlet r, a liquid outlet t and a liquid outlet d, and the liquid storage tank 2 is used for storing brake liquid and detecting the residual quantity of the brake liquid.
The brake pedal 6 comprises a rotating part and a pedal bracket, wherein the rotating part is arranged on the pedal bracket through a pin shaft through hole at the top end of the rotating part and adopts a pin shaft, the rotating part is in rotary connection with the pedal bracket, the pedal bracket is fixed with a vehicle body through a bolt, and the brake pedal 6 amplifies the pedal force of the brake operation of a driver by utilizing the lever principle and can reflect the brake intention of the driver.
The pedal displacement sensor 5 adopts a stay wire type displacement sensor of the German ASM company CLM series, the movable arm on the pedal displacement sensor 5 can be used for measuring the angular displacement of the brake pedal 6, and the angular displacement is fed back to the brake controller for acquiring pedal displacement information of a driver when the brake energy of the automobile is recovered.
The brake master cylinder check valve 3 adopts a straight-through check valve, the forward opening pressure is 0.04MPa, the brake master cylinder check valve 3 is used for controlling the flow direction of brake fluid, and only the brake fluid can flow from the p port to the a port of the brake master cylinder check valve 3, but the brake fluid cannot flow back.
The position and connection mode of the specific components: the brake pedal 6 is arranged below the front part of a driver in a carriage, the top end of a rotating part in the brake pedal 6 is fixed on a pedal bracket through a pin shaft, the pedal bracket is fixed on a vehicle body through a bolt, and the left side surface of the middle end of the rotating part in the brake pedal 6 is in contact connection with the right end surface of a brake master cylinder push rod 4 in a brake master cylinder. The pedal displacement sensor 5 is fixed on a pedal bracket connected to the vehicle body, the pedal displacement sensor 5 is fixed on the pedal bracket connected to the vehicle body, and a movable arm of the pedal displacement sensor 5 is connected to a rotating portion in the brake pedal 6. The brake master cylinder is fixed on the vehicle body through a flange plate, a liquid outlet A of a first chamber of the brake master cylinder is connected with a liquid inlet D of the active brake pedal stroke simulator 12 through a brake pipeline, a liquid outlet B of a second chamber of the brake master cylinder is connected with a liquid inlet E of the active brake pedal stroke simulator 12 through a brake pipeline, and a liquid inlet C of a third chamber of the brake master cylinder is connected with a liquid outlet F of the active brake pedal stroke simulator 12 through a brake pipeline. The liquid outlet f, the liquid outlet r and the liquid outlet t of the liquid storage tank 2 are respectively connected with the liquid inlet a of the first chamber of the brake master cylinder, the liquid inlet b of the second chamber of the brake master cylinder and the liquid inlet c of the third chamber of the brake master cylinder through pipelines, and the liquid storage tank 2 is arranged above the brake master cylinder. The brake master cylinder check valve 3 is arranged between a liquid outlet t of the liquid storage tank 2 and a liquid inlet c of a third chamber of the brake master cylinder, a p port of the brake master cylinder check valve 3 is connected with a liquid outlet t of the liquid storage tank 2 through a hydraulic pipeline, and an a port of the brake master cylinder check valve 3 is connected with a liquid inlet c of the third chamber of the brake master cylinder through a hydraulic pipeline.
Referring to fig. 2 and 3, the active brake pedal travel simulator 12 includes a toothed inner circulation nut 19, a second thrust bearing 20, a first thrust bearing 21, a limit switch 22, a screw rod jack 23, a ball 24, a driving gear 25, a limit switch signal line 26, a first motor fixing bolt 27, a motor 28, a motor controller 29, a diaphragm 44, a fourth rear cover connecting rivet 45, a rear cover 46, a second motor fixing bolt 53, a seventh rear cover connecting rivet 54, a sixth rear cover connecting rivet 56, a fifth rear cover connecting rivet 57, a third rear cover connecting rivet 58, a second rear cover connecting rivet 59, a first rear cover connecting rivet 61, a second piston seal ring 30, a simulator cylinder 31, a third piston seal ring 32, an oil inlet/outlet hole 33, a first piston 34, a third piston 35, a first piston spring 36, a third piston spring 37, a third piston spring seat 38, a third piston retainer ring 39, a second piston 40, a second piston spring 41, a vent hole 42, a second diaphragm connecting bolt 43, a third diaphragm connecting bolt 55, a first diaphragm connecting simulator 60, a third diaphragm connecting simulator solenoid valve 48, a second simulator solenoid valve 52, a third diaphragm electromagnetic valve 50, a simulator hydraulic fluid outlet valve 51, and a simulator solenoid valve 50.
The specific specification and functions are as follows: the active brake pedal travel simulator 12 mainly plays roles in simulating pedal feel and realizing active pressurization, pressure maintaining and active depressurization as a backup energy supply device when the main energy supply device 13 fails.
The toothed internal circulation nut 19 is a disc-type structural member, a cylindrical boss is arranged at the right end of the toothed internal circulation nut 19, the center of the boss coincides with the center of the toothed internal circulation nut 19, teeth meshed with the driving gear 25 are arranged on the outer cylindrical surface on the periphery of the toothed internal circulation nut 19, a central through hole is formed in the center of the toothed internal circulation nut 19, and a spiral rollaway nest for installing the balls 24 is arranged on the inner cylindrical surface of the central through hole.
The screw mandrel 23 consists of a left section and a right section, the left section is a screw mandrel which is matched with a central through hole of the toothed internal circulation nut 19 and the ball 24 and is provided with a spiral rollaway nest, the right section is a cylindrical slide bar with a smooth surface, and the screw mandrel 23 plays a role in converting the rotary motion of the toothed internal circulation nut 19 into linear motion.
The first thrust bearing 21 and the second thrust bearing 20 can adopt thrust ball bearings or thrust cylindrical roller bearings, and the first thrust bearing 21 and the second thrust bearing 20 can bear the radial acting force of the toothed internal circulation nut 19 and can limit the axial displacement of the toothed internal circulation nut 19.
The simulator cylinder 31 is a cylindrical structural member, the left end and the right end of the simulator cylinder are both open, a flange plate for installation is arranged on the outer cylindrical surface of the left end cylinder opening, three bolt holes are uniformly distributed on the flange plate, three-section cylindrical stepped holes are processed along the central axis of the simulator cylinder 31, the diameters of the three-section stepped holes decrease from left to right in sequence, the three-section cylindrical stepped holes are a first section stepped hole, a second section stepped hole and a third section stepped hole in sequence, wherein the second piston 40 and the second piston spring 41 are installed in the first section stepped hole, the first piston 34 and the first piston spring 36 are installed in the second section stepped hole, the third section stepped hole is an oil inlet and outlet hole 33 of the simulator cylinder 31, and are processed into an internal threaded hole, the cylindrical walls of the first section stepped holes are further processed with vent holes 42, and the three-section cylindrical stepped holes are mutually communicated and have rotation axes collinear.
The baffle 44 is a disc-type structural member, the outline of the outer circular surface of the baffle 44 is composed of two eccentric circles and two circumscribed lines of the two eccentric circles, the diameter of an upper eccentric circle on the baffle 44 is larger, the diameter of a lower eccentric circle on the baffle 44 is smaller, two central through holes are processed in the center of the two eccentric circles on the baffle 44, three uniformly distributed bolt holes, two uniformly distributed bolt holes and seven rivet holes are processed on the plane of the baffle 44, the three uniformly distributed bolt hole distribution circles are concentrically arranged with an upper eccentric circle on the baffle 44, the two uniformly distributed bolt hole distribution circles are concentrically arranged with a lower eccentric circle on the baffle 44, the seven uniformly distributed bolt hole distribution circles are concentrically arranged with an upper eccentric circle on the baffle 44, the diameters of the three uniformly distributed bolt hole distribution circles are smaller, the diameters of the seven rivet hole distribution circles are larger, and a circular boss for installing the second thrust bearing 20 is arranged on the left end face of the baffle 44.
The rear cover 46 is a stepped cylindrical structural member, the left end of the rear cover is closed, the right end of the rear cover is open, a central through hole for installing the limit switch 22 is processed at the left end, the outer contour of the outer circular surface of the right end cylinder opening is the same as that of the outer circular surface of the partition plate 44, a flange plate for installation is arranged on the outer circular surface of the right end cylinder opening, and seven rivet holes are formed in the flange plate and are matched with the seven rivet holes in the partition plate 44; the rear cover 46 is provided with two stepped holes, the left end stepped hole is a central circular hole and has a smaller diameter, the inner profile of the right end stepped hole is identical to the outer profile of the outer circular surface of the partition plate 44, the two stepped holes are mutually communicated, the rotating shaft of the left end stepped hole is collinear with the upper eccentric circular rotating shaft of the right end stepped hole, and the left end face of the right end stepped hole is provided with a circular boss for installing the first thrust bearing 21.
The third piston 35 is a two-section stepped shaft, the diameter of the right end shaft is larger, an annular groove for placing the third piston sealing ring 32 is processed on the cylindrical surface of the right end shaft, the diameter of the left end shaft is smaller and is used for mounting the third piston spring 37, a circular groove for placing the third piston spring seat retainer ring 39 is processed on the cylindrical surface of the left end shaft, a circular hole is processed on the left end shaft along the rotation center line of the stepped shaft, and the diameter of the hole is slightly larger than the diameter of the slide rod of the screw mandrel 23.
The first piston 34 is a two-section stepped shaft, the right end shaft diameter is larger, the left end shaft diameter is smaller, the left end shaft diameter is used for installing the third piston spring 37, a circular boss is arranged on the left end face of the larger diameter shaft and used for installing the first piston spring 36, a circular stepped hole is machined along the rotation center line of the stepped shaft, the right end diameter of the stepped hole is larger and equal to the right end shaft diameter of the third piston 35, the left end diameter of the stepped hole is smaller and equal to the left end shaft diameter of the third piston 35.
The second piston 40 is a two-section stepped shaft, the diameter of the right end shaft is larger, a circular boss is arranged on the right end surface and is used for installing the first piston spring 36, an annular groove used for placing the second piston sealing ring 30 is processed on the cylindrical surface of the right end shaft, the diameter of the left end shaft is smaller and is used for installing the second piston spring 41, a circular through hole is processed along the rotation center line of the stepped shaft, and the diameter of the through hole is slightly larger than that of the left end shaft of the first piston 34.
The first piston spring 36 adopts a cylindrical spiral spring, has smaller rigidity, and mainly simulates the pressure volume characteristic of the wheel cylinder during small-intensity braking in a pedal stroke simulation state; the second piston spring 41 is a cylindrical coil spring, the rigidity is larger, the pressure volume characteristic of the wheel cylinder is mainly simulated in a pedal stroke simulation state when the brake is braked at high strength, the third piston spring 37 is a cylindrical coil spring, the rigidity is larger, and the third piston 35 is mainly moved towards the direction of the screw mandrel 23 (namely leftwards relative to the second piston 40) in a decompression state, so that the active decompression function is realized.
The third piston spring seat 38 is a circular structural member and is used for installing and fixing the third piston spring 37.
The third piston spring seat retainer ring 39 is a circular structural member made of aluminum alloy material, and a notch is formed in the circular ring for convenient installation. The third piston spring seat retainer ring 39 functions to limit the axial displacement of the third piston spring seat 38.
The second piston sealing ring 30 and the third piston sealing ring 32 are both O-shaped sealing rings for sealing brake fluid.
The first rear cover attachment rivet 61, the second rear cover attachment rivet 59, the third rear cover attachment rivet 58, the fourth rear cover attachment rivet 45, the fifth rear cover attachment rivet 57, the sixth rear cover attachment rivet 56, and the seventh rear cover attachment rivet 54 are half-head rivets for connecting the rear cover 46 and the partition 44.
The first baffle connecting bolt 60, the second baffle connecting bolt 43 and the third baffle connecting bolt 55 adopt common thin-tooth hexagon bolts for connecting the simulator cylinder 31 and the baffle 44; the first motor fixing bolt 27 and the second motor fixing bolt 53 are common fine hexagon bolts for connecting the motor 28 and the partition 44.
The motor 28 is a brushed direct-current permanent magnet motor, and the motor 28 is a power source of the active brake pedal stroke simulator 12.
The master cylinder pressure sensor 52 is an active pressure sensor with model 303 manufactured by BOSCH corporation, and needs to input 5V power supply voltage to measure the pressure of the master cylinder.
The first liquid outlet electromagnetic valve 50 of the simulator and the second liquid outlet electromagnetic valve 51 of the simulator are two-position two-way normally open electromagnetic valves, can realize the bidirectional flow of brake fluid, and are used for controlling the on-off of the brake master cylinder and the hydraulic adjusting unit 14.
The simulator electromagnetic valve 49 and the simulator third liquid outlet electromagnetic valve 48 are two-position two-way normally closed electromagnetic valves, and can realize bidirectional flow of brake liquid when being electrified, so as to control the on-off of the brake master cylinder and the active brake pedal stroke simulator 12.
The simulator check valve 47 adopts a straight-through check valve, the forward opening pressure is 0.04MPa, the simulator check valve 47 is used for controlling the flow direction of brake fluid, and only the brake fluid can flow from the p port to the a port of the simulator check valve 47, but the brake fluid cannot flow back.
The positions and the connection modes of the specific components are as follows:
the first piston 34 and the second piston 40 are sequentially arranged in the first section stepped hole and the second section stepped hole of the simulator cylinder 31 in a sliding connection mode, the second piston sealing ring 30 is sleeved in an annular groove of the second piston 40, the third piston 35 is sleeved in the first piston 34 in a sliding connection mode, and the third piston sealing ring 32 is sleeved in an annular groove of the third piston 35. The first piston spring 36 is sleeved on a circular boss on the second end face on the left side of the first piston 34, the left end face of the first piston spring 36 is in contact connection with the bottom face of the circular boss on the right end face of the second piston 40, and the right end face of the first piston spring 36 is in contact connection with the bottom face of the circular boss on the left end face of the first piston 34; the second piston spring 41 and the third piston spring 37 are respectively arranged on the left end shafts of the second piston 40 and the third piston 35, the left end surface of the second piston spring 41 is in contact connection with the right end surface of the partition plate 44, the right end surface of the second piston spring 41 is in contact connection with the left end surface of the large-diameter shaft of the second piston 40, the third piston spring seat 38 is sleeved at the left end of the third piston 35 for transition fit, the left end surface of the third piston spring 37 is in contact connection with the right end surface of the third piston spring seat 38, and the right end surface of the third piston spring 37 is in contact connection with the left end surface of the small-diameter shaft of the first piston 34; the preload of the second piston spring 41 is greater than the preload of the first piston spring 36. The third piston spring seat retainer ring 39 is installed in a circular groove at the left end of the third piston 35, and the left end face of the third piston spring seat 38 is in contact connection with the right end face of the third piston spring seat retainer ring 39. The motor 28 is mounted on the right end face of the diaphragm 44 below the simulator cylinder 31 by the first motor fixing bolt 27 and the second motor fixing bolt 53. The motor controller 29 is mounted on the right end face of the motor 28 housing, and the terminals of the motor 28 are connected to the drive output terminals of the motor controller 29, and the motor controller 29 is connected to the brake system controller to receive instructions from the brake system controller. The limit switch 22 is installed at the center of the rear cover 46, the limit switch 22 transmits the collected signals to the motor controller 29 through the limit switch signal line 26, the limit switch 22 is a small-stroke micro switch, and when the screw rod push rod 23 returns to the initial position, the screw rod push rod 23 contacts with the limit switch 22 to generate corresponding signals. The driving gear 25 is sleeved on the output shaft of the motor 28 in interference fit connection, and the driving gear 25 is in meshed connection with the toothed internal circulation nut 19 on the outer circumferential surface. The toothed internal circulation nut 19 is sleeved on the screw rod at the left end of the screw rod ejector rod 23, a ball 24 is arranged in a spiral rollaway nest on a central through hole of the toothed internal circulation nut 19 and a spiral rollaway nest on the screw rod in the screw rod ejector rod 23, the ball 24 can circulate through a circulation rollaway nest (not shown in the figure) in the toothed internal circulation nut 19, and the rotary motion of the toothed internal circulation nut 19 is converted into linear motion of the screw rod ejector rod 23 through the ball 24. The toothed internal circulation nut 19 is arranged between the rear cover 46 and the partition plate 44 through the first thrust bearing 21 and the second thrust bearing 20, the second thrust bearing 20 is sleeved on a boss at the right end of the toothed internal circulation nut 19 in a contact connection mode, the right end face of the toothed internal circulation nut 19 is in contact connection with the left end face of the second thrust bearing 20, the second thrust bearing 20 is sleeved on a circular boss on the left end face of the partition plate 44 in a contact connection mode, the right end face of the second thrust bearing 20 is in contact connection with the left end face of the partition plate 44, the left end face of the toothed internal circulation nut 19 is in contact connection with the right end face of the first thrust bearing 21, the first thrust bearing 21 is sleeved on a circular boss on the inner side of the rear cover 46 in a contact connection mode, and the left end face of the first thrust bearing 21 is in contact connection with the end face of the rear cover 46. The right slide bar part of the screw rod push rod 23 passes through the upper eccentric circular hole on the partition plate 44 and the circular hole on the third piston 35, and has a certain gap with the upper eccentric circular hole and the circular hole. The screw rod 23 may contact the third piston 35 but not the partition 44 when pressurized. When the screw rod 23 returns to the initial position, it does not interfere with the movement of the third piston 35. The simulator cylinder 31 is mounted on the right end face of the partition 44 by three bolts, which are a first partition connecting bolt 60, a second partition connecting bolt 43, and a third partition connecting bolt 55, respectively, and the left end face of the simulator cylinder 31 is in contact connection with the right end face of the partition 44. The rear cover 46 is mounted on the left end face of the partition 44 by seven rivets, the right end face of the rear cover 46 being in contact with the left end face of the partition 44, the seven rivets being a first rear cover connecting rivet 61, a second rear cover connecting rivet 59, a third rear cover connecting rivet 58, a fourth rear cover connecting rivet 45, a fifth rear cover connecting rivet 57, a sixth rear cover connecting rivet 56 and a seventh rear cover connecting rivet 54, respectively. Wherein: the rotation axes of the first piston 34, the second piston 40, the third piston 35, the third piston spring seat 38, the screw rod push rod 23, the toothed internal circulation nut 19, the first thrust bearing 21, the second thrust bearing 20 and the simulator cylinder 31 are collinear, the rotation axis of the output shaft of the motor 28 is collinear with the rotation axis of the driving gear 25, and the rotation axis of the output shaft of the motor 28 is parallel with the rotation axes of the first piston 34, the second piston 40, the third piston 35, the third piston spring seat 38, the screw rod push rod 23, the toothed internal circulation nut 19, the first thrust bearing 21, the second thrust bearing 20 and the simulator cylinder 31. The port a of the simulator solenoid valve 49, the port p of the simulator third liquid outlet solenoid valve 48 and the port a of the simulator check valve 47 are all connected with the oil inlet and outlet hole 33 hydraulic pipeline on the simulator cylinder 31, the port p of the simulator solenoid valve 49 and the port p of the simulator first liquid outlet solenoid valve 50 are all connected with the port D hydraulic pipeline of the active brake pedal stroke simulator 12, the port a of the simulator first liquid outlet solenoid valve 50 is connected with the port G hydraulic pipeline of the active brake pedal stroke simulator 12, the port p of the simulator second liquid outlet solenoid valve 51 and the brake master cylinder pressure sensor 52 are all connected with the port E hydraulic pipeline of the active brake pedal stroke simulator 12, the port a of the simulator second liquid outlet solenoid valve 51 is connected with the port H hydraulic pipeline of the active brake pedal stroke simulator 12, and the port a of the simulator third liquid outlet solenoid valve 48 and the port p of the simulator check valve 47 are all connected with the port F hydraulic pipeline of the active brake pedal stroke simulator 12.
Referring to fig. 4, the main power supply device 13 includes an electro-hydraulic cylinder, an electro-hydraulic cylinder pressure sensor 62, an electro-hydraulic cylinder first outlet solenoid valve 63, and an electro-hydraulic cylinder second outlet solenoid valve 64.
The specific specification and functions are as follows: the main energy supply device 13 is mainly used as a braking system energy supply device to realize the functions of active pressurization, pressure maintaining and active depressurization.
The electric hydraulic cylinder comprises an electric hydraulic cylinder body 65, an electric hydraulic cylinder piston spring 66, an electric hydraulic cylinder piston 67, an electric hydraulic cylinder ball screw 68 and an electric hydraulic cylinder motor 69; the electric hydraulic cylinder body 65 is a cylindrical structural member, the left end and the right end of the electric hydraulic cylinder body 65 are provided with holes, the left end is provided with holes with smaller diameters and is processed into threaded holes, the holes are electric hydraulic cylinder oil inlet and outlet holes a, the right end is provided with holes with larger diameters, and the outer cylindrical surface of the electric hydraulic cylinder body 65 is provided with oil inlet and outlet holes p; the center of the right end of the electric hydraulic cylinder piston 67 is provided with a center hole, the inner cylindrical surface of the center hole is provided with a spiral rollaway nest for mounting balls, and the electric hydraulic cylinder ball screw 68 is provided with a spiral rollaway nest matched with the spiral rollaway nest of the electric hydraulic cylinder piston 67; the electric hydraulic cylinder piston spring 66 and the electric hydraulic cylinder piston 67 are sequentially arranged in the electric hydraulic cylinder body 65, the electric hydraulic cylinder piston 67 is in sliding connection with the electric hydraulic cylinder body 65, the left end of the electric hydraulic cylinder ball screw 68 is arranged in a central hole at the right end of the electric hydraulic cylinder piston 67 and is in rolling connection, the right end of the electric hydraulic cylinder ball screw 68 is connected with the electric hydraulic cylinder motor 69 through a transmission mechanism (not shown in the figure), and the electric hydraulic cylinder ball screw 68 can convert the rotary motion of the electric hydraulic cylinder motor 69 into the linear motion of the electric hydraulic cylinder piston 67.
The electro-hydraulic cylinder pressure sensor 62 is an active pressure sensor with model 303 manufactured by BOSCH company, and needs to input 5V supply voltage to measure the pressure of the main power supply device 13.
The first liquid outlet electromagnetic valve 63 of the electric hydraulic cylinder and the second liquid outlet electromagnetic valve 64 of the electric hydraulic cylinder are two-position two-way normally closed electromagnetic valves, can realize the bidirectional flow of brake fluid, and are used for controlling the on-off of the main energy supply device 13 and the hydraulic adjusting unit 14.
The positions and the connection modes of the specific components are as follows: the p port of the first liquid outlet electromagnetic valve 63 of the electric hydraulic cylinder, the p port of the second liquid outlet electromagnetic valve 64 of the electric hydraulic cylinder and the pressure sensor 62 of the electric hydraulic cylinder are all connected with an a hydraulic pipeline of an oil inlet and outlet hole of the electric hydraulic cylinder, the a port of the first liquid outlet electromagnetic valve 63 of the electric hydraulic cylinder is connected with an I port hydraulic pipeline of the main power supply device 13, the a port of the second liquid outlet electromagnetic valve 64 of the electric hydraulic cylinder is connected with a J port hydraulic pipeline of the main power supply device 13, and the p port of the oil inlet and outlet hole of the electric hydraulic cylinder is connected with a K port hydraulic pipeline of the main power supply device 13.
Referring to fig. 5, the hydraulic pressure adjusting unit 14 includes a right rear wheel check valve 70, a right rear wheel inlet solenoid valve 71, a left front wheel check valve 72, a left front wheel inlet solenoid valve 73, a right front wheel check valve 74, a right front wheel inlet solenoid valve 75, a left rear wheel check valve 76, a left rear wheel inlet solenoid valve 77, a right rear wheel outlet solenoid valve 78, a left front wheel outlet solenoid valve 79, a right front wheel outlet solenoid valve 80, and a left rear wheel outlet solenoid valve 81.
The specific specification and functions are as follows: the hydraulic pressure adjusting unit 14 has a function of adjusting the brake cylinder pressure.
The right rear wheel liquid inlet solenoid valve 71, the left front wheel liquid inlet solenoid valve 73, the right front wheel liquid inlet solenoid valve 75 and the left rear wheel liquid inlet solenoid valve 77 are two-position two-way normally open solenoid valves, and respectively control the pressurization of the right rear wheel 15, the left front wheel 16, the right front wheel 17 and the left rear wheel 18.
The right rear wheel liquid outlet solenoid valve 78, the left front wheel liquid outlet solenoid valve 79, the right front wheel liquid outlet solenoid valve 80 and the left rear wheel liquid outlet solenoid valve 81 are two-position two-way normally closed solenoid valves for respectively controlling the decompression of the right rear wheel 15, the left front wheel 16, the right front wheel 17 and the left rear wheel 18.
The right rear wheel check valve 70, the left front wheel check valve 72, the right front wheel check valve 74, and the left rear wheel check valve 76 define that the flow direction of the brake fluid can flow only in one direction.
The positions and the connection modes of the specific components are as follows: the port a of the right rear wheel check valve 70, the port P of the right rear wheel liquid inlet solenoid valve 71, the port a of the left front wheel liquid inlet solenoid valve 72 and the port P of the left front wheel liquid inlet solenoid valve 73 are all connected with the M port hydraulic pipeline of the hydraulic pressure regulating unit 14, the port a of the right front wheel check valve 74, the port P of the right front wheel liquid inlet solenoid valve 75, the port a of the left rear wheel check valve 76 and the port P of the left rear wheel liquid inlet solenoid valve 77 are all connected with the L port hydraulic pipeline of the hydraulic pressure regulating unit 14, the port P of the right rear wheel check valve 70, the port a of the right rear wheel liquid inlet solenoid valve 71 and the port P of the right rear wheel liquid outlet solenoid valve 78 are all connected with the Q port hydraulic pipeline of the hydraulic pressure regulating unit 14, the port P of the left front wheel check valve 72, the port a of the left front wheel liquid outlet solenoid valve 73 and the port P of the left front wheel liquid outlet solenoid valve 79 are all connected with the P port hydraulic pipeline of the hydraulic pressure regulating unit 14, the port P of the left front wheel check valve 74, the port a of the right front wheel liquid outlet solenoid valve 80 and the left front wheel solenoid valve 14 a are all connected with the O port of the hydraulic pressure regulating unit 14, the port P of the left front wheel solenoid valve 80 and the port of the left front wheel solenoid valve 14 a is connected with the port of the left front wheel solenoid valve 14.
The connection relationship among the brake operating mechanism 1, the active brake pedal travel simulator 12, the main energy supply device 13 and the hydraulic pressure adjusting unit 14 of the brake-by-wire system with the backup function is as follows: the driver directly controls the brake operating mechanism 1, and finally, the hydraulic adjusting unit 14 controls the wheels to brake, and an active brake pedal stroke simulator 12 and a main energy supply device 13 are arranged in parallel between the output end of the brake operating mechanism 1 and the input end of the hydraulic adjusting unit 14. The output end of the brake operating mechanism 1 comprises a first cavity liquid outlet A of a brake master cylinder, a second cavity liquid outlet B of the brake master cylinder and a third cavity liquid inlet C of the brake master cylinder, wherein the first cavity liquid outlet A of the brake master cylinder is connected with a liquid inlet D of the active brake pedal stroke simulator 12 through a brake pipeline, the second cavity liquid outlet B of the brake master cylinder is connected with a liquid inlet E of the active brake pedal stroke simulator 12 through a brake pipeline, the third cavity liquid inlet C of the brake master cylinder is connected with a liquid outlet F of the active brake pedal stroke simulator 12 through a brake pipeline, a liquid outlet G of the active brake pedal stroke simulator 12 and a liquid outlet I of the main energy supply device 13 are connected with a liquid inlet M of the hydraulic pressure regulating unit 14 through a brake pipeline, a liquid outlet H of the active brake pedal stroke simulator 12 and a liquid outlet J of the main energy supply device 13 are connected with a liquid inlet L of the hydraulic pressure regulating unit 14 through a brake pipeline, and a liquid inlet K of the main energy supply device 13 and a liquid outlet R of the hydraulic pressure regulating unit 14 are connected with a liquid outlet D of the liquid storage tank 2 through a brake pipeline.
The brake-by-wire system with the backup function not only can simulate pedal feel through the active brake pedal travel simulator 12 when the main energy supply device 13 works (pressure regulation), but also can dynamically regulate the brake master cylinder pressure and pedal feel through the active pressure regulation function of the active brake pedal travel simulator 12 after the main energy supply device 13 fails, thereby realizing the redundant backup design of the brake system while ensuring that the brake pedal feel is consistent with that of a traditional automobile and ensuring the driving safety to the greatest extent.
Referring to fig. 6, a control method of a brake-by-wire system with backup function according to the present invention is as follows:
step one: whether the displacement of the brake pedal 6 is 0 is detected, and the brake controller receives a pedal displacement signal transmitted from the pedal displacement sensor 5. If the pedal displacement is 0, the step II is entered, otherwise, the step III is entered.
Step two: when the pedal displacement is 0, the brake controller sends an operating state instruction to the simulator motor controller 29 to be in an idle state, so that the active brake pedal stroke simulator 12 is in the idle state, when the screw rod ejector 23 is in an initial position, the motor 28 does not work, when the screw rod ejector 23 is not in the initial position, the motor controller 29 drives the motor 28 to reversely rotate, the motor 28 converts the rotary motion of the motor 28 into the linear motion of the screw rod ejector 23 through the driving gear 25, the toothed internal circulation nut 19, the ball 24 and the screw rod ejector 23, the screw rod ejector 23 moves leftwards until the left end of a sliding rod of the screw rod ejector 23 contacts with the limit switch 22, and the limit switch 22 transmits acquired signals to the motor controller 29 through the limit switch signal wire 26, so that the screw rod ejector 23 is considered to be in the initial position. Meanwhile, the main power supply device 13 is also in an idle state, when the electric hydraulic cylinder piston 67 is in an initial position, the electric hydraulic cylinder motor 69 does not work, when the electric hydraulic cylinder piston 67 is not in the initial position, the electric hydraulic cylinder motor 69 is driven to reversely rotate, the electric hydraulic cylinder motor 69 converts rotary motion into linear motion of the electric hydraulic cylinder piston 67 through the electric hydraulic cylinder ball screw 68, the electric hydraulic cylinder piston 67 moves rightwards to the initial position, whether the electric hydraulic cylinder piston 67 returns or not is judged through the rotating speed of the electric hydraulic cylinder motor 69, when the rotating speed of the electric hydraulic cylinder motor 69 is lower than a threshold w, the electric hydraulic cylinder piston 67 is considered to return, and the threshold w is required to be obtained through test calibration; when the pedal displacement is 0 and the screw rod 23 in the active brake pedal travel simulator 12 and the electro-hydraulic cylinder piston 67 in the main power supply device 13 have all been returned, the brake system does not operate.
Step three: when the pedal displacement is greater than 0, a target master cylinder pressure P is calculated Master cylinder tar The brake controller receives pedal displacement signals transmitted by the pedal displacement sensor 5, and obtains target master cylinder pressure P under corresponding pedal displacement according to a relation curve of traditional automobile pedal displacement and master cylinder pressure measured by test Master cylinder tar 。
Step four: the brake controller sends an operating state command to the simulator motor controller 29 to a pedal stroke simulation state, so that the active brake pedal stroke simulator 12 is in the pedal stroke simulation state, when the screw rod jack 23 is already in the initial position, the motor 28 does not operate, and when the screw rod jack 23 is not in the initial position, the motor controller 29 drives the motor 28 to rotate reversely, so that the screw rod jack 23 is operated to the initial position. Thereafter, the simulator solenoid valve 49 is opened, the simulator first outlet solenoid valve 50, the simulator second outlet solenoid valve 51, and the simulator third outlet solenoid valve 48 are all closed, and the front axle brake fluid is entirely introduced into the active brake pedal travel simulator 12, with the pedal feel being provided entirely by the active brake pedal travel simulator 12. In order to match the pedal feel with the conventional brake pedal feel, it is necessary to match the parameters of the first piston spring 36, the second piston spring 41, the first piston 34, and the second piston 40 of the active brake pedal stroke simulator 12 so that the brake pedal stroke simulator can accurately simulate the wheel cylinder pressure volume characteristics, ensuring the pedal feel. The electro-hydraulic cylinder first outlet solenoid valve 63 and the electro-hydraulic cylinder second outlet solenoid valve 64 are both open, and the wheel cylinder pressure is all supplied from the main power supply device 13.
Step five: the brake controller receives a pressure signal P of the main power supply device 13 transmitted by the electric hydraulic cylinder pressure sensor 62 Electro-hydraulic cylinder act . If the main power supply device 13 is a pressure signal P Electro-hydraulic cylinder act Less than the target master cylinder pressure P Master cylinder tar Step six is entered; if the main power supply device 13 is a pressure signal P Electro-hydraulic cylinder act Equal to the target master cylinder pressure P Master cylinder tar Step seven is entered; otherwise, step eight is entered.
Step six: pressure signal P of main power supply device 13 Electro-hydraulic cylinder act Less than the target master cylinder pressure P Master cylinder tar When the main power supply device 13 is in a pressurized state, the electric hydraulic cylinder motor 69 is driven to rotate in the forward direction, the electric hydraulic cylinder motor 69 converts the rotary motion into the linear motion of the electric hydraulic cylinder piston 67 through the electric hydraulic cylinder ball screw 68, the electric hydraulic cylinder piston 67 moves leftwards, and when the electric hydraulic cylinder piston 67 moves to the electric hydraulic cylinder oil inlet and outlet hole p, the main power supply device 13 starts to build pressure and the actual pressure gradually rises.
Step seven: pressure signal P of main power supply device 13 Electro-hydraulic cylinder act Equal to the target master cylinder pressure P Master cylinder tar When the main power supply device 13 is in a pressure maintaining state, the electric hydraulic cylinder motor 69 is static, and the electric hydraulic cylinder ball screw 68 and the electric hydraulic cylinder piston 67 keep the original positions so as to keep the actual pressure of the main power supply device 13 unchanged.
Step eight: pressure signal P of main power supply device 13 Electro-hydraulic cylinder act Greater than target master cylinder pressure P Master cylinder tar When the main power supply device 13 is in a decompression state, the electric hydraulic cylinder motor 69 is driven to reversely rotate, the electric hydraulic cylinder motor 69 converts rotary motion into linear motion of the electric hydraulic cylinder piston 67 through the electric hydraulic cylinder ball screw 68, the electric hydraulic cylinder piston 67 moves rightwards, the actual pressure of the main power supply device 13 is gradually reduced, after the electric hydraulic cylinder piston 67 returns to the electric hydraulic cylinder oil inlet and outlet hole p, the actual pressure of the main power supply device 13 is reduced to 0, and after the electric hydraulic cylinder piston 67 returns, the decompression process is ended.
Step nine: the brake controller receives the pressure signal P of the main power supply device 13 transmitted by the electric hydraulic cylinder pressure sensor 62 again Electro-hydraulic cylinder act To determine whether the main power supply device 13 fails, if the main power supply device 13 fails, step ten is entered, otherwise, step one is returned.
Step ten: the electro-hydraulic cylinder first outlet solenoid valve 63 and the electro-hydraulic cylinder second outlet solenoid valve 64 are closed, the simulator solenoid valve 49 is closed, the simulator first outlet solenoid valve 50, the simulator second outlet solenoid valve 51 and the simulator third outlet solenoid valve 48 are all opened, and at this time, the wheel cylinder pressures are all provided by the master cylinder.
Step eleven: the brake controller receives a master cylinder pressure signal P transmitted from a master cylinder pressure sensor 52 Brake master cylinder act . If the master cylinder pressure signal P Brake master cylinder act Less than the target master cylinder pressure P Master cylinder tar Step twelve is entered; if the master cylinder pressure signal P Brake master cylinder act Equal to the target master cylinder pressure P Master cylinder tar Step thirteenth is entered; otherwise, step fourteen is entered.
Step twelve: master cylinder pressure signal P Brake master cylinder act Less than the target master cylinder pressure P Master cylinder tar When the brake controller sends a working state instruction to the simulator motor controller 29 to be in a pressurizing state, so that the active brake pedal stroke simulator 12 is in the pressurizing state, the motor controller 29 sends a control instruction to enable the motor 28 to rotate positively, the motor 28 converts rotary motion into linear motion of the screw rod ejector rod 23 through the driving gear 25, the toothed internal circulation nut 19, the ball 24 and the screw rod ejector rod 23, when the screw rod ejector rod 23 moves to be in contact with the third piston 35, the third piston 35 starts to move rightwards relative to the first piston 34, the pressurizing process starts, the third piston 35 is continuously pushed along with the screw rod ejector rod 23, and the pressurizing process is continuously carried out. Brake fluid enters a third chamber of the brake master cylinder through the simulator oil inlet and outlet hole 33 and the simulator third liquid outlet electromagnetic valve 48, and the active pressurization and pedal feel simulation work is completed by adjusting the active brake pedal travel simulator 12 in real time, so that the actual pressure of the brake master cylinder is gradually increased.
Step thirteen: master cylinder pressure signal P Brake master cylinder act Equal to the target master cylinder pressure P Master cylinder tar When the brake controller sends a working state instruction to the simulator motor controller 29 to be in a pressure maintaining state, so that the active brake pedal stroke simulator 12 is in the pressure maintaining state, the motor controller 29 sends a control instruction to enable the motor 28 to be static, and the screw mandrel 23 and the third piston 35 keep the original position unchanged, so that the actual pressure of the brake master cylinder is kept unchanged.
Step fourteen: master cylinder pressure signal P Brake master cylinder act Greater than target master cylinder pressure P Master cylinder tar When the brake controller sends a working state instruction to the simulator motor controller 29 to be in a decompression state, so that the active brake pedal stroke simulator 12 is in a decompression state, the motor controller 29 sends a control instruction to enable the motor 28 to reversely rotate, the motor 28 converts the rotary motion into linear motion of the screw mandrel 23 through the driving gear 25, the toothed internal circulation nut 19, the ball 24 and the screw mandrel 23 until the screw mandrel 23 moves to be in contact with the limit switch 22, the screw mandrel 23 returns to an initial position, and the third piston 35 is opposite to the first piston under the action of the third piston spring 37 and high-pressure brake fluid A piston 34 moves leftwards until a third piston 35 returns, brake fluid in a third chamber of the brake master cylinder flows back to the active brake pedal stroke simulator 12 through a simulator check valve 47 and a simulator oil inlet and outlet hole 33, and the active pressure reduction and pedal feel simulation work is completed by adjusting the active brake pedal stroke simulator 12 in real time, so that the actual pressure of the brake master cylinder is gradually reduced until the pressure reduction process is finished.
Fifteen steps: returning to the first step.
Claims (5)
1. The brake-by-wire system with the backup function is characterized by comprising a brake operating mechanism (1), an active brake pedal stroke simulator (12), a main energy supply device (13) and a hydraulic adjusting unit (14);
the brake control mechanism (1) comprises a brake master cylinder and a liquid storage tank (2);
the brake master cylinder is internally provided with three chambers which are arranged in series, namely a first chamber, a second chamber and a third chamber from left to right, wherein a liquid outlet A of the first chamber of the brake master cylinder is connected with a liquid inlet D of the active brake pedal stroke simulator (12), a liquid outlet B of the second chamber of the brake master cylinder is connected with a liquid inlet E of the active brake pedal stroke simulator (12), a liquid inlet C of the third chamber of the brake master cylinder is connected with a liquid outlet F of the active brake pedal stroke simulator (12) through a brake pipeline, a liquid outlet G of the active brake pedal stroke simulator (12) and a liquid outlet I of the main energy supply device (13) are connected with a liquid inlet M of the hydraulic pressure regulating unit (14) through brake pipelines, a liquid outlet H of the active brake pedal stroke simulator (12) and a liquid outlet J of the main energy supply device (13) are connected with a liquid inlet L of the hydraulic pressure regulating unit (14) through brake pipelines, and a liquid inlet K of the main energy supply device (13) and a liquid outlet R of the hydraulic pressure regulating unit (14) are connected with a liquid outlet D of the tank (2);
The active brake pedal stroke simulator (12) comprises a motor controller (29), a motor (28), a driving gear (25), a toothed internal circulation nut (19), balls (24), a screw mandrel (23), a limit switch (22), a rear cover (46), a partition plate (44), a first thrust bearing (21), a second thrust bearing (20), a second piston (40), a second piston spring (41), a second piston sealing ring (30), a first piston (34), a first piston spring (36), a third piston (35), a third piston spring (37), a third piston spring seat (38), a third piston spring seat retainer ring (39), a third piston sealing ring (32), a simulator cylinder body (31), a simulator one-way valve (47), a simulator third liquid outlet electromagnetic valve (48), a simulator electromagnetic valve (49), a simulator first liquid outlet electromagnetic valve (50), a simulator second liquid outlet electromagnetic valve (51) and a brake master cylinder pressure sensor (52);
the simulator cylinder body (31) is arranged on the right end face of the partition plate (44) through bolts, the rear cover (46) is arranged on the left end face of the partition plate (44) through rivets, the toothed inner circulation nut (19) is arranged between the rear cover (46) and the partition plate (44) through the first thrust bearing (21) and the second thrust bearing (20), the left end face of the first thrust bearing (21) is in contact connection with the rear cover (46), the right end face of the first thrust bearing (21) is in contact connection with the toothed inner circulation nut (19), the left end face of the second thrust bearing (20) is in contact connection with the toothed inner circulation nut (19), the left end rollaway nest of the screw mandrel (23) is arranged in a spiral rollaway nest of a central hole of the toothed inner circulation nut (19), the right end of the screw mandrel (23) is inserted into a stepped hole of the simulator cylinder body (31), the right end of the screw mandrel (23) is sleeved with a third piston (35), the left end of the screw mandrel (23) is sleeved with the second piston (40) in the stepped hole, the second piston section (34) is sleeved with the second piston section (34) in the stepped hole, the second piston section (40) is sequentially connected with the first piston section (34), the first piston spring (36) is sleeved on a circular boss on the second end face of the left side of the first piston (34), the second piston spring (41) is installed on the left end shaft of the second piston (40), the third piston spring (37) is installed on the left end shaft of the third piston (35), the third piston spring seat (38) is sleeved on the left end of the third piston (35) for transition fit, the third piston spring seat retainer ring (39) is installed in a circular groove on the left end of the third piston (35), the left end face of the third piston spring seat (38) is in contact connection with the right end face of the third piston spring seat retainer ring (39), the second piston seal ring (30) is sleeved in an annular groove of the second piston (40), the third piston seal ring (32) is sleeved in an annular groove of the third piston (35), the motor (28) is installed on the right end face of a partition plate (44) below the simulator cylinder (31), the driving gear (25) is sleeved on the output shaft of the motor (28) for fit connection, the driving gear (25) is in interference fit connection with the motor (19), the motor (29) is in interference fit connection with the motor (29), the motor (29) is meshed with the motor (28) and the motor (29) is installed on the central controller (22) at the position, the limit switch (22) is connected with the motor controller (29) through a limit switch signal line (26), the port a of the simulator solenoid valve (49), the port p of the simulator third liquid outlet solenoid valve (48) and the port a of the simulator check valve (47) are all connected with an oil inlet and outlet hole (33) hydraulic pipeline on the simulator cylinder body (31), the port p of the simulator solenoid valve (49) and the port p of the simulator first liquid outlet solenoid valve (50) are all connected with a port D hydraulic pipeline of the active brake pedal stroke simulator (12), the port a of the simulator first liquid outlet solenoid valve (50) is connected with a port G hydraulic pipeline of the active brake pedal stroke simulator (12), the port p of the simulator second liquid outlet solenoid valve (51) and the port E of the brake master cylinder pressure sensor (52) are all connected with a port E hydraulic pipeline of the active brake pedal stroke simulator (12), and the port a of the simulator third liquid outlet solenoid valve (48) and the port a port p of the simulator check valve (52) are all connected with a port H hydraulic pipeline of the active brake pedal stroke simulator (12);
The simulator cylinder body (31) is a cylindrical structural member, the left end and the right end of the simulator cylinder body are both open, a flange plate for installation is arranged on the outer cylindrical surface of a cylinder opening at the left end, three bolt holes are uniformly distributed on the flange plate, three-section cylindrical stepped holes are processed along the central axis of the simulator cylinder body (31), the diameters of the three-section stepped holes decrease from left to right in sequence, the three-section cylindrical stepped holes are a first section stepped hole, a second section stepped hole and a third section stepped hole in sequence, a second piston (40) and a second piston spring (41) are installed in the first section stepped hole, a first piston (34) and a first piston spring (36) are installed in the second section stepped hole, the third section stepped hole is an oil inlet and outlet hole (33) of the simulator cylinder body (31), and are processed into an internal threaded hole, the cylindrical wall of the first section stepped hole is also processed into an air vent (42), and the three section cylindrical stepped holes are communicated with each other and the rotation axes are collinear;
the third piston (35) is a two-section stepped shaft, the right end shaft diameter of the third piston is larger than the left end shaft diameter, an annular groove for placing a sealing ring is formed in the cylindrical surface of the right end shaft, the left end shaft is used for mounting a third piston spring (37), a circular groove for placing a third piston spring seat retainer ring (39) is formed in the cylindrical surface of the left end shaft, a circular hole is formed in the left end shaft along the rotation center line of the stepped shaft, and the diameter of the circular hole is larger than that of a right end sliding rod of the screw mandrel (23); the first piston (34) is a two-section stepped shaft, the right end shaft diameter of the first piston is larger than the left end shaft diameter, the left end shaft diameter is used for installing a third piston spring (37), a circular boss is arranged on the left end surface of the shaft with larger diameter and used for installing the first piston spring (36), a circular stepped hole is machined along the rotation center line of the stepped shaft, the right end diameter of the stepped hole is larger than the left end diameter of the stepped hole, the right end diameter of the stepped hole is equal to the right end shaft diameter of the third piston (35), and the left end diameter of the stepped hole is equal to the left end shaft diameter of the third piston (35); the second piston (40) is a two-section stepped shaft, the right end shaft diameter of the second piston is larger than the left end shaft diameter, a circular boss is arranged on the right end surface and used for mounting the first piston spring (36), an annular groove used for placing a sealing ring is formed in the cylindrical surface of the right end shaft, the left end shaft is used for mounting the second piston spring (41), a circular through hole is formed along the rotation center line of the stepped shaft, and the diameter of the through hole is larger than that of the left end shaft diameter of the first piston (34);
The brake master cylinder comprises a brake master cylinder body (7), a brake master cylinder first piston (10), a brake master cylinder second piston (8), a brake master cylinder first piston spring (11), a brake master cylinder second piston spring (9) and a brake master cylinder push rod (4), wherein the brake master cylinder body (7) is a cylindrical structural member, the left end of the brake master cylinder body is closed, the right end of the brake master cylinder body is opened, a flange disc is arranged on the right end surface of the brake master cylinder body, six liquid inlets and liquid outlets are arranged on the outer cylindrical surface of the brake master cylinder body (7), the six liquid inlets are respectively arranged on the outer cylindrical surface of the brake master cylinder body, the brake master cylinder first piston spring (11), the brake master cylinder first piston (10), the brake master cylinder second piston (9), the brake master cylinder second piston (8) and the brake master cylinder push rod (4) are sequentially arranged in the brake master cylinder body (7), the brake master cylinder first piston (10), the brake master cylinder second piston (8) and the brake master cylinder second piston (7) are in sliding connection, the brake master cylinder first piston (11), the brake master cylinder first piston (10), the brake cylinder second piston (9) and the brake master cylinder second piston (8) are arranged in a series, three independent brake cylinder chambers are formed by the brake master cylinder first piston and the brake cylinder second piston (8), the brake master cylinder comprises a first chamber, a second chamber and a third chamber from left to right, wherein a mechanical inlet of the brake master cylinder is a brake master cylinder push rod (4), and the brake master cylinder is fixed on a vehicle body through a flange plate;
The liquid storage tank (2) have four liquid outlets, namely a liquid outlet f, a liquid outlet r, a liquid outlet t and a liquid outlet d, wherein the liquid outlet f is connected with a liquid inlet a of a first chamber of the brake master cylinder through a pipeline, the liquid outlet r is connected with a liquid inlet b of a second chamber of the brake master cylinder through a pipeline, the liquid outlet t is connected with a liquid inlet c of a third chamber of the brake master cylinder through a pipeline, and the liquid storage tank (2) is arranged above the brake master cylinder.
2. A brake-by-wire system with backup function according to claim 1, characterized in that the brake operating mechanism (1) further comprises a brake pedal (6), a pedal displacement sensor (5), a brake master cylinder check valve (3);
the brake pedal (6) is arranged below the front part of a driver in a carriage, the top end of a rotating part in the brake pedal (6) is fixed on a pedal bracket through a pin shaft, the pedal bracket is fixed on a vehicle body through a bolt, the left side surface of the middle end of the rotating part in the brake pedal (6) is in contact connection with the right end surface of a brake master cylinder push rod (4) in a brake master cylinder, a pedal displacement sensor (5) is fixed on the pedal bracket connected with the vehicle body, a movable arm of the pedal displacement sensor (5) is connected with the rotating part in the brake pedal (6), a brake master cylinder check valve (3) is arranged between a liquid outlet t of a liquid storage tank (2) and a liquid inlet c of a brake master cylinder third chamber, and a port of the brake master cylinder check valve (3) is connected with a liquid outlet t of the liquid storage tank (2) through a liquid pipeline.
3. A brake-by-wire system with backup function according to claim 1, characterized in that said main power supply means (13) comprise an electro-hydraulic cylinder, an electro-hydraulic cylinder pressure sensor (62), an electro-hydraulic cylinder first outlet solenoid valve (63), an electro-hydraulic cylinder second outlet solenoid valve (64);
the electric hydraulic cylinder comprises an electric hydraulic cylinder body (65), an electric hydraulic cylinder piston spring (66), an electric hydraulic cylinder piston (67), an electric hydraulic cylinder ball screw (68) and an electric hydraulic cylinder motor (69); the electric hydraulic cylinder body (65) is a cylindrical structural member, the left end and the right end of the electric hydraulic cylinder body are provided with holes, the diameter of the left end hole is smaller than that of the right end hole, the left end hole is processed into a threaded hole, the threaded hole is an electric hydraulic cylinder oil inlet and outlet hole a, and an oil inlet and outlet hole p is formed in the outer cylindrical surface of the electric hydraulic cylinder body (65); the center of the right end of the electric hydraulic cylinder piston (67) is provided with a center hole, the inner cylindrical surface of the center hole is provided with a spiral rollaway nest for mounting balls, and the electric hydraulic cylinder ball screw (68) is provided with a spiral rollaway nest matched with the spiral rollaway nest of the electric hydraulic cylinder piston (67); the electric hydraulic cylinder piston spring (66) and the electric hydraulic cylinder piston (67) are sequentially arranged in the electric hydraulic cylinder body (65), the electric hydraulic cylinder piston (67) is in sliding connection with the electric hydraulic cylinder body (65), the left end of the electric hydraulic cylinder ball screw (68) is arranged in a central hole at the right end of the electric hydraulic cylinder piston (67) and is in rolling connection, the right end of the electric hydraulic cylinder ball screw (68) is connected with the electric hydraulic cylinder motor (69) through a transmission mechanism, and the electric hydraulic cylinder ball screw (68) can convert the rotary motion of the electric hydraulic cylinder motor (69) into the linear motion of the electric hydraulic cylinder piston (67);
The p-port of the first liquid outlet electromagnetic valve (63) of the electric hydraulic cylinder, the p-port of the second liquid outlet electromagnetic valve (64) of the electric hydraulic cylinder and the pressure sensor (62) of the electric hydraulic cylinder are all connected with an oil inlet and outlet hole a hydraulic pipeline of the electric hydraulic cylinder, the a-port of the first liquid outlet electromagnetic valve (63) of the electric hydraulic cylinder is connected with an I-port hydraulic pipeline of the main energy supply device (13), the a-port of the second liquid outlet electromagnetic valve (64) of the electric hydraulic cylinder is connected with a J-port hydraulic pipeline of the main energy supply device (13), and the oil inlet and outlet hole p of the electric hydraulic cylinder is connected with a K-port hydraulic pipeline of the main energy supply device (13).
4. A brake-by-wire system with backup function according to claim 1, characterized in that the hydraulic pressure regulating unit (14) comprises a right rear wheel check valve (70), a right rear wheel inlet solenoid valve (71), a left front wheel check valve (72), a left front wheel inlet solenoid valve (73), a right front wheel check valve (74), a right front wheel inlet solenoid valve (75), a left rear wheel check valve (76), a left rear wheel inlet solenoid valve (77), a right rear wheel outlet solenoid valve (78), a left front wheel outlet solenoid valve (79), a right front wheel outlet solenoid valve (80), a left rear wheel outlet solenoid valve (81);
The port a of the right rear wheel one-way valve (70), the port P of the right rear wheel liquid inlet electromagnetic valve (71), the port a of the left front wheel one-way valve (72) and the port P of the left front wheel liquid inlet electromagnetic valve (73) are all connected with an M-port hydraulic pipeline of the hydraulic adjusting unit (14), the port a of the right front wheel one-way valve (74), the port P of the right front wheel liquid inlet electromagnetic valve (75), the port a of the left rear wheel one-way valve (76), the port P of the left rear wheel liquid inlet electromagnetic valve (77) are all connected with an L-port hydraulic pipeline of the hydraulic adjusting unit (14), the port P of the right rear wheel one-way valve (70), the port a of the right rear wheel liquid inlet electromagnetic valve (71), the port P of the right rear wheel liquid outlet electromagnetic valve (78) are all connected with a Q-port hydraulic pipeline of the hydraulic adjusting unit (14), the port P of the left front wheel one-way valve (72), the port a of the left front wheel liquid inlet electromagnetic valve (73), the port P of the left front wheel liquid outlet electromagnetic valve (79) are all connected with a P-port of the hydraulic adjusting unit (14), the port P-port P of the left front wheel one-way valve (14) is connected with a-port P of the hydraulic adjusting unit (14), the port P-port P of the left rear wheel one-way valve (76) is connected with a-port of the left front wheel one-way valve (14), the port a of the right rear wheel liquid outlet electromagnetic valve (78), the port a of the left front wheel liquid outlet electromagnetic valve (79), the port a of the right front wheel liquid outlet electromagnetic valve (80) and the port a of the left rear wheel liquid outlet electromagnetic valve (81) are all connected with an R port hydraulic pipeline of the hydraulic adjusting unit (14).
5. A control method of a brake-by-wire system with a backup function as claimed in any one of claims 1-4, characterized by the steps of:
1) detecting whether the displacement of a brake pedal (6) is 0, receiving a pedal displacement signal transmitted by a pedal displacement sensor (5) by a brake controller, if the pedal displacement is 0, entering a step 2), otherwise, entering a step 3);
2) When the pedal displacement is 0, a working state instruction sent to a motor controller (29) by a brake controller is in an idle state, so that an active brake pedal stroke simulator (12) is in the idle state, when the screw rod ejector rod (23) is in an initial position, a motor (28) does not work, when the screw rod ejector rod (23) is not in the initial position, the motor controller (29) drives the motor (28) to reversely rotate, the motor (28) converts the rotary motion of the motor (28) into the linear motion of the screw rod ejector rod (23) through a driving gear (25), a toothed internal circulation nut (19), a ball (24) and the screw rod ejector rod (23), the screw rod ejector rod (23) moves leftwards until the left end of a slide rod of the screw rod ejector rod (23) is in contact with a limit switch (22), and the limit switch (22) transmits acquired signals to the motor controller (29) through a limit switch signal wire (26), and at the moment, the screw rod ejector rod (23) is considered to be in the initial position; meanwhile, the main energy supply device (13) is in an idle state, when the electric hydraulic cylinder piston (67) is in an initial position, the electric hydraulic cylinder motor (69) does not work, when the electric hydraulic cylinder piston (67) is not in the initial position, the electric hydraulic cylinder motor (69) is driven to reversely rotate, the electric hydraulic cylinder motor (69) converts rotary motion into linear motion of the electric hydraulic cylinder piston (67) through an electric hydraulic cylinder ball screw (68), the electric hydraulic cylinder piston (67) moves rightwards to the initial position, whether the electric hydraulic cylinder piston (67) returns or not is judged through the rotating speed of the electric hydraulic cylinder motor (69), and when the rotating speed of the electric hydraulic cylinder motor (69) is lower than a threshold value w, the electric hydraulic cylinder piston (67) is considered to return; when the pedal displacement is 0 and the screw rod ejector rod (23) in the active brake pedal stroke simulator (12) and the electro-hydraulic cylinder piston (67) in the main energy supply device (13) are all returned, the brake system does not work;
3) When the pedal displacement is greater than 0, a target master cylinder pressure P is calculated Master cylinder tar ；
4) The brake controller sends a working state instruction to the motor controller (29) to be in a pedal stroke simulation state, so that the active brake pedal stroke simulator (12) is in the pedal stroke simulation state, when the screw rod ejector rod (23) is in an initial position, the motor (28) does not work, when the screw rod ejector rod (23) is not in the initial position, the motor controller (29) drives the motor (28) to reversely rotate, so that the screw rod ejector rod (23) is operated to the initial position, after that, the simulator electromagnetic valve (49) is opened, the simulator first liquid outlet electromagnetic valve (50), the simulator second liquid outlet electromagnetic valve (51) and the simulator third liquid outlet electromagnetic valve (48) are all closed, and front axle brake liquid completely enters the active brake pedal stroke simulator (12); the first liquid outlet electromagnetic valve (63) of the electric hydraulic cylinder and the second liquid outlet electromagnetic valve (64) of the electric hydraulic cylinder are opened, and at the moment, the wheel cylinder pressure is provided by the main energy supply device (13);
5) The brake controller receives a pressure signal P of a main power supply device (13) transmitted by an electro-hydraulic cylinder pressure sensor (62) Electro-hydraulic cylinder act If the pressure signal P of the main power supply device (13) Electro-hydraulic cylinder act Less than the target master cylinder pressure P Master cylinder tar Step 6) is entered if the pressure signal P of the primary power supply means (13) Electro-hydraulic cylinder act Equal to the target master cylinder pressure P Master cylinder tar Step 7) is entered, otherwise step 8) is entered;
6) Pressure signal P of main power supply device (13) Electro-hydraulic cylinder act Less than the target master cylinder pressure P Master cylinder tar When the main energy supply device (13) is in a supercharging state, the electric hydraulic cylinder motor (69) is driven to rotate positively, the electric hydraulic cylinder motor (69) converts rotary motion into linear motion of the electric hydraulic cylinder piston (67) through the electric hydraulic cylinder ball screw (68), the electric hydraulic cylinder piston (67) moves leftwards, and when the electric hydraulic cylinder piston (67) moves to the electric hydraulic cylinder oil inlet and outlet hole p, the main energy supply device (13) starts to build pressure and the actual pressure gradually rises;
7) Pressure signal P of main power supply device (13) Electro-hydraulic cylinder act Equal to the target master cylinder pressure P Master cylinder tar When the main energy supply device (13) is in a pressure maintaining state, the electric hydraulic cylinder motor (69) is static, and the electric hydraulic cylinder ball screw (68) and the electric hydraulic cylinder piston (67) keep the original positions so as to keep the actual pressure of the main energy supply device (13) unchanged;
8) Pressure signal P of main power supply device (13) Electro-hydraulic cylinder act Greater than target master cylinder pressure P Master cylinder tar When the main power supply device (13) is in a decompression state, the electric hydraulic cylinder motor (69) is driven to reversely rotate, and the electric hydraulic cylinder motor (69) converts the rotary motion into the electric hydraulic cylinder piston (67) through the electric hydraulic cylinder ball screw (68)The electric hydraulic cylinder piston (67) moves rightwards through linear movement, the actual pressure of the main energy supply device (13) is gradually reduced, when the electric hydraulic cylinder piston (67) returns to the electric hydraulic cylinder oil inlet and outlet hole p, the actual pressure of the main energy supply device (13) is reduced to 0, and after the electric hydraulic cylinder piston (67) returns, the decompression process is finished;
9) The brake controller receives the pressure signal P of the main energy supply device (13) transmitted by the electric hydraulic cylinder pressure sensor (62) again Electro-hydraulic cylinder act Judging whether the main energy supply device (13) fails, if the main energy supply device (13) fails, entering the step 10), otherwise returning to the step 1);
10 The first liquid outlet electromagnetic valve (63) of the electric hydraulic cylinder and the second liquid outlet electromagnetic valve (64) of the electric hydraulic cylinder are closed, the simulator electromagnetic valve (49) is closed, the first liquid outlet electromagnetic valve (50) of the simulator, the second liquid outlet electromagnetic valve (51) of the simulator and the third liquid outlet electromagnetic valve (48) of the simulator are opened, and at the moment, the wheel cylinder pressure is provided by the brake master cylinder;
11 Brake controller receives a master cylinder pressure signal P transmitted from a master cylinder pressure sensor (52) Brake master cylinder act If the master cylinder pressure signal P Brake master cylinder act Less than the target master cylinder pressure P Master cylinder tar Step 12) is entered, if the master cylinder pressure signal P Brake master cylinder act Equal to the target master cylinder pressure P Master cylinder tar Step 13) is entered, otherwise step 14) is entered;
12 Brake master cylinder pressure signal P Brake master cylinder act Less than the target master cylinder pressure P Master cylinder tar When the brake controller sends an operating state instruction to the motor controller (29) to be in a supercharging state, so that the active brake pedal stroke simulator (12) is in the supercharging state, the motor controller (29) sends a control instruction to enable the motor (28) to rotate positively, the motor (28) converts rotary motion into linear motion of the screw rod ejector rod (23) through the driving gear (25), the toothed internal circulation nut (19), the ball (24) and the screw rod ejector rod (23), and when the screw rod ejector rod (23) moves to be in contact with the third piston (35), the third piston (35) is opposite to the first pistonA piston (34) starts to move rightwards, a pressurizing process starts, along with the continuous pushing of a third piston (35) by a screw rod ejector rod (23), the pressurizing process is continuously carried out, brake fluid enters a third chamber of a brake master cylinder through an oil inlet and outlet hole (33) of a simulator and a third liquid outlet electromagnetic valve (48) of the simulator, and the active pressurizing and pedal feel simulation work is completed by adjusting an active brake pedal stroke simulator (12) in real time, so that the actual pressure of the brake master cylinder is gradually increased;
13 Brake master cylinder pressure signal P Brake master cylinder act Equal to the target master cylinder pressure P Master cylinder tar When the brake controller sends a working state instruction to the motor controller (29) to be in a pressure maintaining state, so that the active brake pedal stroke simulator (12) is in the pressure maintaining state, the motor controller (29) sends a control instruction to enable the motor (28) to be static, and the screw rod ejector rod (23) and the third piston (35) keep the original positions so as to keep the actual pressure of the brake master cylinder unchanged;
14 Brake master cylinder pressure signal P Brake master cylinder act Greater than target master cylinder pressure P Master cylinder tar When the brake controller sends a working state instruction to the motor controller (29) to be in a decompression state, so that the active brake pedal stroke simulator (12) is in a decompression state, the motor controller (29) sends a control instruction to enable the motor (28) to reversely rotate, the motor (28) converts rotary motion into linear motion of the screw rod ejector rod (23) through the driving gear (25), the toothed internal circulation nut (19), the ball (24) and the screw rod ejector rod (23) until the screw rod ejector rod (23) moves to be in contact with the limit switch (22), the screw rod ejector rod (23) returns to an initial position, the third piston (35) moves leftwards relative to the first piston (34) under the action of the third piston spring (37) and high-pressure brake fluid until the third piston (35) returns, brake master cylinder III chamber brake fluid flows back to the active brake pedal stroke simulator (12) through the simulator check valve (47) and the simulator oil inlet and outlet hole (33), and the active brake pedal feel simulation work is completed through real-time adjustment of the brake pedal stroke simulator (12), and the actual brake master cylinder pressure gradually decreases until the decompression process is finished;
15 Returning to step 1).
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| CN113771811B (en) * | 2021-10-22 | 2022-06-10 | 吉林大学 | Automobile brake-by-wire system with backup function and pressure control method thereof |
| JP2023104541A (en) * | 2022-01-18 | 2023-07-28 | 株式会社アドヴィックス | Electric cylinder device |
| CN114954403B (en) * | 2022-05-10 | 2023-06-23 | 浙江亚太机电股份有限公司 | Hydraulic line control braking system |
| CN114604216B (en) * | 2022-05-10 | 2023-06-23 | 浙江亚太机电股份有限公司 | Chassis integrated braking system |
| CN114954404B (en) * | 2022-05-10 | 2023-08-11 | 浙江亚太机电股份有限公司 | Chassis line control braking system |
| CN115626146A (en) * | 2022-09-21 | 2023-01-20 | 清华大学 | Hydraulic braking supercharging device, braking system and vehicle |
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