CN112896125B

CN112896125B - Split type electro-hydraulic braking system and braking control method thereof

Info

Publication number: CN112896125B
Application number: CN202110246945.1A
Authority: CN
Inventors: 王亚; 邓伟文
Original assignee: Nanjing Jingweida Automobile Technology Co ltd
Current assignee: Nanjing Jingweida Automobile Technology Co ltd
Priority date: 2021-03-05
Filing date: 2021-03-05
Publication date: 2021-11-26
Anticipated expiration: 2041-03-05
Also published as: CN112896125A

Abstract

The invention discloses a split type electro-hydraulic braking system which comprises a first liquid storage tank, a manual cylinder, a brake pedal, an ABS/ESC electromagnetic valve, a second liquid storage tank, an electro-hydraulic braking device, a main cylinder and a brake. The hydraulic brake system comprises a manual cylinder, a brake, a wheel cylinder, a hydraulic pipeline, a first oil inlet, an oil outlet, an ABS/ESC electromagnetic valve, a first oil storage tank, a second oil storage tank, a hydraulic pipeline, a hydraulic oil storage tank, a hydraulic oil inlet, a hydraulic oil storage tank, a hydraulic oil outlet, a hydraulic oil storage tank, a hydraulic oil outlet, a brake control system and a brake system, wherein the first oil inlet on the manual cylinder is communicated with the first liquid storage tank; the electro-hydraulic brake device is connected with the main cylinder, and an oil outlet on the main cylinder is communicated with a second oil inlet arranged on the manual cylinder through a hydraulic pipeline; the manual cylinder is internally provided with a lever, a first piston, a piston ejector rod and a second piston, and an idle stroke is arranged between the piston ejector rod and the second piston. The brake control method of the split type electro-hydraulic brake system can realize the modes of autonomous braking, line control braking, power-assisted braking, failure backup manual braking and the like, and has the advantages of small axial installation space, higher output brake pressure and higher brake energy recovery efficiency.

Description

Split type electro-hydraulic braking system and braking control method thereof

Technical Field

The invention relates to an automobile braking system, in particular to a split type electro-hydraulic braking system and a braking control method thereof.

Background

With the continuous development of the pure electric vehicle technology, the requirements on the endurance mileage of the pure electric vehicle are higher and higher. There are many ways to increase the endurance mileage of an electric vehicle, such as increasing the upper limit of reserve of a power battery, and reducing the average power consumption. Among them, the most effective technical means is to improve the efficiency of braking energy recovery.

In recent years, the market is successively provided with a BoseiBooster electromechanical servo boosting mechanism and a servo device with the structure and the function similar to the BoseiBooster electromechanical servo boosting mechanism, the servo device reserves small sections of idle strokes to support energy recovery of an electric vehicle, and meanwhile, the servo motor is adopted to output braking torque and provide boosting after speed reduction and torque increase of transmission mechanisms such as an internal gear rack, a worm gear and the like.

However, some heavy-load vehicles have a high requirement on the upper limit of the maximum braking pressure, if the conventional scheme of the existing electro-hydraulic servo device is adopted, a large-torque and large-volume motor needs to be selected, an internal transmission device needs to be increased to ensure the strength of parts, so that the volume of the whole device is very large, even if the performance of the electro-hydraulic braking system meets the requirement on the braking pressure function, the electro-hydraulic braking system is often limited by the fact that the installation space of the whole vehicle cannot be installed, and the requirement on the electro-hydraulic servo braking of a heavy-load vehicle cannot be met.

Disclosure of Invention

In view of the above, the present invention aims to overcome the defects of the prior art, and provides a split type electro-hydraulic brake system with small axial installation space, higher output pressure and higher brake energy recovery efficiency on the premise of satisfying the deceleration regulation of human backup.

In order to achieve the purpose, the invention provides a split type electro-hydraulic brake system, which comprises a first liquid storage tank, a manpower cylinder, a brake pedal, an ABS/ESC electromagnetic valve, a second liquid storage tank, a master cylinder, an electro-hydraulic brake device and a brake, wherein: the brake pedal is connected with the manual cylinder and used for driving the manual cylinder; the manual cylinder is provided with a first oil inlet communicated with the first liquid storage tank, the manual cylinder is provided with an oil outlet and communicated with an oil inlet of the ABS/ESC electromagnetic valve through a hydraulic pipeline, and the oil outlet of the ABS/ESC electromagnetic valve is communicated with a wheel cylinder of the brake through a hydraulic pipeline; the electro-hydraulic brake device is connected with the master cylinder and used for driving the master cylinder; the oil inlet on the main cylinder is communicated with the second liquid storage tank, and the oil outlet on the main cylinder is communicated with a second oil inlet arranged on the manual cylinder through a hydraulic pipeline;

the manual cylinder is provided with a pedal connecting assembly and is provided with a first piston cylinder body, a second piston cylinder body and an end cover which are fixed mutually; a lever which is pushed by the pedal connecting assembly to rotate, a first piston which is pushed by the lever and a piston ejector rod which is pushed by the first piston are arranged in the first piston cylinder, a first cavity is formed among the first piston cylinder, the first piston and the second piston cylinder, and the first piston and the piston ejector rod are movably arranged in the first cavity; a second piston pushed by the piston mandril is arranged in the second piston cylinder body, the second piston divides the closed space between the second piston cylinder body and the end cover into a second chamber and a third chamber, and the front end part of the piston mandril movably extends into the second chamber; an oil through hole communicated with the second chamber and the third chamber is further formed in the second piston, a sealing pin used for abutting against the second piston and sealing the oil through hole is arranged at the front end of the piston ejector rod, and a gap (namely an idle stroke) is formed between the sealing pin and the second piston in an initial state; the third chamber is connected with the first liquid storage tank through the first oil inlet and is connected with the ABS/ESC electromagnetic valve and the first liquid storage tank through the oil outlet; the first cavity and the second cavity are communicated with the main cylinder through the second oil inlet respectively.

Further, a piston ejector rod return spring for resetting the piston ejector rod is arranged in the first cavity, a piston return spring for resetting the second piston is arranged in the third cavity, a gap is formed between the sealing pin and the second piston under the action of the sealing pretightening force of the piston ejector rod return spring and the piston return spring in an initial state, and the second cavity is communicated with the third cavity through the oil through hole. The idle stroke is a gap S between the seal pin and the oil passage hole of the second piston. In one embodiment, the seal pin and the oil through hole of the second piston are sealed by conical surfaces, and the idle stroke between the seal pin and the second piston, namely the gap S between the conical surface of the seal pin and the conical surface of the piston (namely the idle stroke), can be used for supporting energy recovery. Before the idle stroke is finished, if the master cylinder of the electro-hydraulic brake device outputs brake pressure to the manual cylinder, high-pressure brake fluid directly enters the third chamber through the oil through hole of the second piston.

Furthermore, one end of the lever is rotatably connected in the first piston cylinder body, a first rolling shaft is arranged in the middle of the lever and used for pushing the first piston, and a second rolling shaft is arranged at the other end of the lever; one end of the pedal connecting component is connected with the brake pedal, and the other end of the pedal connecting component movably penetrates into the first piston cylinder and is abutted against the second rolling shaft on the lever; and a sensor magnet is arranged at the end part of one end of the lever, which is far away from the second rolling shaft, and a corner sensor for sensing the sensor magnet is arranged at the outer side of the lever.

Furthermore, a damping piston is arranged between the first roller and the first piston, one end of the damping piston is arranged in a concave hole of the first piston, the other end of the damping piston abuts against the first roller, and a damping spring is further arranged between the damping piston and the first piston.

Furthermore, a cushion block, a guide gasket tightly attached to the cushion block and a first leather cup tightly attached to the guide gasket are further arranged in the second piston cylinder body. A spring seat is arranged on the first piston, one end of the piston ejector rod is fixed on the spring seat, and the other end of the piston ejector rod sequentially penetrates through the cushion block, the guide gasket, the first leather cup and an inner through hole of the second piston cylinder body to enter the second chamber; and the second piston is also provided with a second leather cup.

In a specific embodiment, at least two groups of piston push rods and at least two groups of second pistons are arranged, each group is independently arranged and is jointly pushed by the first piston, and concave holes where the second pistons are located are not communicated with each other. After the design is adopted, after the pressure build failure of one of the two independent hydraulic chambers in the manual cylinder, the pressure build can still be realized through the other chamber, and the hydraulic redundant braking is realized. When the electro-hydraulic brake device of the system fails, the manual force can still push the piston to generate brake pressure through the brake pedal, the pedal connecting assembly and the lever, and the failure backup manual brake is realized.

Further, the electro-hydraulic brake device comprises a shell and an end cover installed on the shell. A motor, a transmission mechanism connected with the motor, an ejector rod in transmission fit with the transmission mechanism and an end surface propped by the ejector rod are arranged in the shell, a push rod return spring is arranged between the end surface and the shell, and a main cylinder push rod is also arranged on the end surface; a main cylinder piston is arranged in the main cylinder, and one end of the main cylinder piston is arranged in the length extending direction of the main cylinder push rod;

the electro-hydraulic brake device is also internally provided with a controller and a displacement sensor for detecting the displacement of the ejector rod, and the controller is respectively electrically connected with the displacement sensor and the motor.

Furthermore, the transmission mechanism comprises a worm gear transmission mechanism and a gear rack transmission mechanism which are in transmission fit, a worm of the worm gear transmission mechanism is connected with an output shaft of the motor, and a worm wheel of the worm gear transmission mechanism drives the ejector rod through the gear rack transmission mechanism.

The basic principle of the electro-hydraulic brake device is as follows: the stroke sensor obtains pedal stroke to identify driver intention and sends the intention to the controller, when a seal pin of the manual cylinder is in contact with the second piston, a motor is controlled to output target torque after a piston mandril runs through an idle stroke, the target torque is converted into the mandril to push the main cylinder to move through a transmission mechanism of a worm gear and a gear rack in the electric cylinder, so that brake pressure is output to a high-pressure oil inlet of the manual cylinder, and the piston of the manual cylinder is pushed to provide assistance or is directly transmitted to a wheel cylinder of the brake from an oil through hole in the middle of the second piston to execute friction braking. The master cylinder is connected with an electro-hydraulic brake device, and can realize the linear brake function according to the pedal stroke.

Preferably, in one embodiment, the first reservoir and the second reservoir are a common reservoir.

Further, the brake includes a left front brake, a left rear brake, a right front brake, and a right rear brake. The four actuators may be combined according to the number of the third chambers. For example, in a particular embodiment, where the manual cylinders are designed with two third chambers, the arrangement of the four brakes may be divided into a first brake group comprising the right front brake and the left rear brake and a second brake group comprising the right rear brake and the left front brake. Each set of brakes is connected to the oil outlet of one third chamber through an ABS/ESC solenoid valve. When the pressure build-up of one of the third chambers is failed, the other third chamber can still output high-pressure brake fluid, and redundant braking is realized.

The invention also provides a brake control method of the split type electro-hydraulic brake system, which comprises the following four brake modes:

1. autonomous braking mode

An autonomous braking mode: when other electric control systems on the automobile send braking requests to the controller of the electro-hydraulic braking device, the controller of the electro-hydraulic braking device drives the main cylinder to generate pressure through the motor, brake fluid is respectively output to the first cavity and the second cavity, and flows to the third cavity through the oil through hole (236) of the second piston to build pressure; and the brake fluid after pressure building flows to the ABS/ESC electromagnetic valve and finally acts on a wheel cylinder of the brake to realize autonomous braking.

2. Brake by wire mode

When a driver steps on a brake pedal, the pedal connecting assembly pushes the lever to rotate, so that the first piston is pushed; the first piston pushes the piston mandril and the sealing pin to move, and the braking system is in a brake-by-wire mode before a gap between the sealing pin and the second piston is eliminated. In the brake-by-wire mode, the pedal force is not transmitted to the piston ram until the gap S is eliminated, i.e. the braking system is decoupled, the braking force required by the vehicle being generated by regenerative braking of the vehicle' S power motor. At this time, the magnitude of the target braking force depends on the pedal stroke. Under a brake-by-wire mode, indirectly obtaining a pedal stroke according to the rotation of the lever detected by a rotation angle sensor arranged on a manual cylinder, calculating a target braking force according to the pedal stroke, and generating a required braking force by the feedback braking of a power motor of the automobile; when the power battery of the automobile is not allowed to be charged or the feedback braking force of the power motor is lower than the target braking force, the motor is controlled by the electro-hydraulic braking device to drive the main cylinder, the main cylinder outputs braking fluid to the first cavity and the second cavity after generating pressure, and the braking fluid directly flows to the third cavity through the oil through hole of the second piston to build pressure; and the brake fluid after pressure building flows to the ABS/ESC electromagnetic valve and finally acts on a wheel cylinder of the brake to realize the brake-by-wire.

3. Boosted braking mode

After the clearance S is eliminated by increasing the stroke of the brake pedal, the brake system works in the boosting mode. The brake deceleration in the boosting mode is larger than 0.3g, at the moment, the regenerative braking is quitted, and the braking force is completely provided by the friction brake. At the moment, the pedal stroke is increased, and the manual brake pushes the piston to generate brake pressure. The controller controls a servo motor of the electro-hydraulic brake device to output a target torque according to a set brake boosting-pedal stroke target curve, drives the motor to output a brake torque, converts the brake torque into a thrust force through a transmission mechanism to provide boosting, and pushes a second piston together with manpower transmitted to a piston ejector rod to implement servo braking. Specifically, when a driver steps on a brake pedal, the pedal connecting assembly pushes the lever to rotate, so that the first piston is pushed; the first piston pushes the piston mandril and the sealing pin to move, and after a gap between the sealing pin and the second piston is eliminated, the braking system works in a power-assisted braking mode; the pedal stroke continues to increase, a controller of the electro-hydraulic brake device controls a motor to drive a main cylinder according to the rotation of a lever detected by a rotation angle sensor arranged on a manual cylinder, and the main cylinder outputs brake fluid to a first cavity and a second cavity after generating pressure, so that boosting force is generated to drive a piston ejector rod and a sealing pin, and the second piston is further pushed; the thrust generated by the second piston and the manpower transmitted to the piston mandril push the brake fluid in the third chamber together to build pressure; and the brake fluid after pressure building flows to the ABS/ESC electromagnetic valve and finally acts on a wheel cylinder of the brake to realize power-assisted braking.

4. Failure backup manual braking mode

When the electro-hydraulic brake device fails, after a driver steps on a brake pedal, as long as the pedal stroke is large enough, the brake pedal can be transmitted to the second piston through the pedal connecting assembly, the lever, the first piston, the piston mandril and the sealing pin to generate brake pressure so as to implement manual backup braking. Specifically, the pedal connecting assembly pushes the lever to rotate, so that the first piston is pushed, the piston mandril and the sealing pin are pushed by the first piston, the second piston is further pushed, and the pushing force generated by the second piston pushes the brake fluid in the third chamber to build pressure; and the brake fluid after pressure building flows to the ABS/ESC electromagnetic valve and finally acts on a wheel cylinder of the brake to realize failure backup manual braking.

Compared with the prior art, the invention has the following beneficial effects:

1. the split type electro-hydraulic braking system provided by the invention can maximize the braking energy recovery efficiency on the premise of meeting the deceleration rule of manpower backup by setting the idle stroke.

2. The manpower cylinder and the electric cylinder of the split type electro-hydraulic brake system can be independently and separately arranged, so that the manpower cylinder and the electric cylinder are simpler in structure and smaller in size, the manpower cylinder can be arranged on a vehicle with a smaller installation space size in the X direction of a cab and an engine cabin, and the electric cylinder can be flexibly arranged on other places with space and lower height than the manpower cylinder of the whole vehicle.

3. According to the invention, the three chambers are arranged in the manual cylinder to enhance the braking assistance, the piston mandril is driven by the brake fluid in the first chamber to push the second piston, and meanwhile, the brake fluid in the second chamber can assist to push the second piston or directly enter the third chamber from the oil through hole in the second piston to finally act on the brake group, so that the brake group can provide enough braking assistance for a large-sized vehicle on the premise of meeting split arrangement, and the braking requirement of the large-sized vehicle is met.

4. The split type electro-hydraulic brake system has an autonomous brake function, and can continue to expand specific functions, such as brake-by-wire, AUTOHOLD, abrupt slope speed reduction and the like.

Drawings

Fig. 1 is a schematic structural principle diagram of a split type electro-hydraulic brake system of the invention.

Fig. 2 is an axial sectional schematic view of an electro-hydraulic brake device of a split electro-hydraulic brake system according to the present invention.

Fig. 3 is a schematic sectional view taken along line a-a of fig. 2.

FIG. 4 is a perspective view of a manual cylinder of a split electro-hydraulic brake system of the present invention.

FIG. 5 is a schematic longitudinal cross-sectional view of a manual cylinder of a split electro-hydraulic brake system according to the present invention.

Fig. 6 is a schematic cross-sectional view taken along the direction B in fig. 5.

In the drawings: 1-a first liquid storage tank, 2-a manpower cylinder, 3-a brake pedal, 4-an ABS/ESC electromagnetic valve, 5-a right front brake, 10-a left front brake, 11-a left rear brake, 6-a right rear brake, 7-a second liquid storage tank, 8-a main cylinder and 9-an electro-hydraulic brake device;

901-end cover, 902-ejector pin, 903-main cylinder push rod, 904-shell, 905-worm gear transmission mechanism, 906-displacement sensor, 907-gear rack transmission mechanism, 908-motor, 909-end face, 910-main cylinder piston, 911-push rod return spring;

201-U type hinge, 202-positioning nut, 203-bulb push rod, 204-bulb connecting piece, 205-return spring, 206-firewall connecting flange, 207-lever, 208-sensor magnet, 209-first piston cylinder body, 210-first piston, 211-damping spring, 212-damping piston, 213-piston snap ring, 214-first roller, 215-second roller, 216-guide seat, 217-push rod, 218-elastic pad;

219-a second piston, 220-a fixed pin, 221-a spring seat, 222-a piston rod return spring, 223-a piston rod, 224-a cushion block, 225-a guide gasket, 226-a second piston cylinder, 227-an end cover, 228-a piston return spring, 229-a second piston, 230-a second leather cup, 231-a seal pin, 232-a cylindrical pin, 233-a first leather cup, 234-a first O-ring, 235-a second O-ring, 236-an oil through hole, 237-an abutting opening, 238-a first chamber, 239-a second chamber, 240-a third chamber;

e-second oil inlet, F-oil outlet, G-first oil inlet.

Detailed Description

The present invention will be further described in detail with reference to the following specific examples, which are carried out on the premise of the technical solution of the present invention, and detailed embodiments and specific operation procedures are provided, but the present invention is not limited to the following examples.

Referring to fig. 1-6, a split type electro-hydraulic brake system comprises a first liquid storage tank 1, a manual cylinder 2, a brake pedal 3, an ABS/ESC solenoid valve 4, a right front brake 5, a left front brake 10, a left rear brake 11, a right rear brake 6, a second liquid storage tank 7, a master cylinder 8, and an electro-hydraulic brake device 9. In the present embodiment, there are 4 brakes each having a wheel cylinder for performing friction braking. An oil inlet of the ABS/ESC electromagnetic valve 4 is communicated with an oil outlet F of the manual cylinder 2 through a hydraulic pipeline, and the oil outlet F is communicated with wheel cylinders of 4 brakes through the hydraulic pipeline. In the present embodiment, the 4 brakes are divided into two groups, including a first brake group including the right front brake 5 and the left rear brake 11, and a second brake group including the right rear brake 6 and the left front brake 10. Each group of brake sets is communicated with an oil outlet of the ABS/ESC electromagnetic valve 4 through a three-way joint. In other embodiments, the number of brakes may be 1, 2, 3 or other number, and multiple brakes may be arranged in different combinations by communicating through hydraulic lines. For example, 4 brakes may also be arranged: the first brake group includes a right front brake 5 and a right rear brake 6, and the second brake group includes a left front brake 10 and a left rear brake 11.

The manual cylinder part comprises a brake pedal 3, a brake pedal connecting assembly, a manual cylinder 2 driven by the brake pedal 3 and a first liquid storage tank 1 communicated with a first oil inlet G of the manual cylinder 2. The electric cylinder part comprises a main cylinder 8 communicated with a second oil inlet E of the manual cylinder 2 through a hydraulic pipeline, a second liquid storage tank 7 connected with the main cylinder 8, and an electric hydraulic brake device 9 for controlling the main cylinder 8 to supply liquid to the manual cylinder 2, wherein the electric hydraulic brake device 9 is also provided with a controller and is used for driving a motor 908 therein to output brake torque. In this embodiment, the first liquid storage tank 1 and the second liquid storage tank 7 are independently arranged, and in other embodiments, the first liquid storage tank 1 and the second liquid storage tank 7 can use the same liquid storage tank.

Specifically, the brake pedal connecting assembly comprises a U-shaped hinge 201, a positioning nut 202, a ball push rod 203, a ball connecting piece 204 and a return spring 205. A positioning nut 202 is arranged between the U-shaped hinge 201 and the ball push rod 203, and the positioning nut 202 can position the thread length of the ball push rod 203 and the direction of the U-shaped hinge 201. The ball head push rod 203 is connected with a ball head connecting piece 204 through a ball head structure; the ball head connection 204 is connected with a push rod 217 through threads, and an elastic pad 218 is arranged between the ball head connection 204 and the push rod 217. The return spring 205 is sleeved on the push rod 217, one end of the return spring is propped against the ball head connecting piece 204, and the other end of the return spring is propped against the firewall connecting flange 206; a guide seat 216 is also arranged between the push rod 217 and the firewall connecting flange 206; the guide seat 216 is connected to the firewall connecting flange 206 by bolts, and plays a role of guiding the push rod 217.

The manual cylinder 2 is provided with a first piston cylinder body 209, a second piston cylinder body 226 and an end cover 227 which are fixed; the first piston cylinder 209 is provided therein with a lever 207 which is rotated by the pedal connecting assembly, a first piston 210 which is pushed by the lever 207, and a piston rod 223 which is pushed by the first piston 210, a first chamber 238 is formed among the first piston cylinder 209, the first piston 210, and the second piston cylinder 226, and the first piston 210 and the piston rod 223 are movably disposed in the first chamber 238. A concave hole is formed in the second piston cylinder 226, a second piston 229 pushed by a piston rod 223 is arranged in the concave hole, the second piston 229 divides the closed space between the second piston cylinder 226 and the end cover 227 into a second chamber 239 and a third chamber 240, and the front end of the piston rod 223 movably extends into the second chamber 239. The second piston 229 is further provided with an oil hole 236 communicating the second chamber 239 and the third chamber 240, the front end portion of the piston rod 223 is provided with a seal pin 231 for abutting against the second piston 229 and sealing the oil hole 236, and in an initial state, a gap is formed between the seal pin 231 and the second piston 229. The third chamber 240 is connected with the first liquid storage tank 1 through a first oil inlet G, and is connected with the ABS/ESC solenoid valve 4 and the first liquid storage tank 1 through an oil outlet F; the first and

second chambers

238 and 239 are respectively communicated with the master cylinder 8 through the second oil inlets E.

The second piston cylinder 226 is provided with a pad 224, a guide washer 225 closely attached to the pad 224, and a first cup 233 closely attached to the guide washer 225, and the pad 224, the guide washer 225, and the first cup 233 are disposed in the first chamber 238 to prevent the brake fluid in the first chamber 238 from flowing to the second chamber 239.

A piston rod return spring 222 for returning the piston rod 223 is arranged in the first chamber 238, a piston return spring 228 for returning the second piston 229 is arranged in the third chamber 240, a gap is formed between the seal pin 231 and the second piston 229 under the pre-tightening force of the piston rod return spring 222 and the piston return spring 228 in the initial state, and the second chamber 239 and the third chamber 240 can be communicated through an oil through hole 236. This idle stroke is a gap S between the seal pin 231 and the oil passage hole 236 of the second piston 229. In this embodiment, the seal pin 231 and the oil through hole 236 of the second piston 229 are sealed by a tapered surface, and the idle stroke between the seal pin 231 and the second piston 229, that is, the gap S (i.e., idle stroke) between the tapered surface of the seal pin 231 and the tapered surface of the piston, may be used to support energy recovery. Before the idle stroke is completed, if the master cylinder 8 of the electro-hydraulic brake device 9 outputs the brake pressure to the manual cylinder 2, the high-pressure brake fluid directly enters the third chamber 240 from the second chamber 239 through the oil passage hole 236 of the second piston 229.

The first piston 210 of the manual cylinder 2 is pushed by a lever 207, one end of the lever 207 is rotatably connected in the first piston cylinder 209, a first roller 214 is arranged in the middle of the lever 207 to push the first piston 210, and a second roller 215 is arranged at the other end of the lever 207; one end of the pedal connecting component is connected with the brake pedal 3 through a U-shaped hinge 201, and the other end of the pedal connecting component movably penetrates into the first piston cylinder 209 through a push rod 217 and is abutted against the second rolling shaft 215 on the lever 207. In this embodiment, the push rod 217 is offset on one side of the manual cylinder 2, the end of the lever 207 remote from the second roller 215 is provided with a sensor magnet 208, and the outer side of the lever 207 is provided with a rotation angle sensor (not shown) that senses the sensor magnet 208 corresponding to the sensor magnet 208. The pedal travel can be obtained indirectly by the rotation angle sensor.

A damping piston 212 is disposed between the first roller 214 and the first piston 210, one end of the damping piston 212 is mounted in a concave hole of the first piston 210 through a piston snap spring 213, and the other end abuts against the first roller 214, and a damping spring 211 is further disposed between the damping piston 212 and the first piston 210. The damping piston 212 is provided with two holes, 2 spring seats 221 are arranged on the damping piston 212, the spring seats 221 are connected with the piston mandril 223 through threads, and the piston mandril return spring 222 is sleeved on the piston mandril 223; the piston jack return spring 222 has one end in contact with the spring seat 221 and the other end in contact with the pad 224. A guide gasket 225 is arranged in the second piston cylinder 226, and the other end of the piston top rod 223 penetrates through the cushion block 224 and the guide gasket 225 and extends into the second chamber 239; the guide washer 225 has one end adjacent the spacer 224 and the other end adjacent the first cup 233. The guide washer 225 is provided with a first O-ring 234 and a second O-ring 235 for preventing the brake fluid from leaking.

The damping piston 212 dampens the direct impact between the lever 207 and the first piston 210 after the brake pedal 3 is depressed.

In the present embodiment, two sets of piston rods 223 and

second pistons

219 and 229 and related components are disposed in the second piston cylinder 226, and are pushed together by the first piston 210. The recesses of the second piston cylinder 226 for accommodating the two

second pistons

219, 229 are not in communication with each other. The two second chambers 239 formed are respectively communicated with the master cylinder 8; the two third chambers 240 are connected with the ABS/ESC solenoid valve 4 and the first liquid storage tank 1 respectively. A second cup 230 is also provided on each of the second pistons 229. When one of the oil paths fails and brake fluid pressure cannot be applied to the ABS/ESC solenoid valve through the second piston 219, the other oil path may serve as a back-up function. In other embodiments, more sets of piston rams 223 may be provided to brake with the second piston structure.

Referring to fig. 2 and 3, the electro-hydraulic brake apparatus 9 includes a housing 904 and an end cap 901 mounted on the housing 904. The shell 904 is internally provided with a motor 908, a transmission mechanism connected with the motor 908, a top rod 902 in transmission fit with the transmission mechanism and an end face 909 propped against by the top rod 902, a push rod return spring 911 is arranged between the end face 909 and the shell 904, and a main cylinder push rod 903 is further arranged on the end face 909. A master cylinder piston 910 is provided in the master cylinder 8, and one end of the master cylinder piston 910 is provided in the direction in which the master cylinder push rod 903 extends in length. A controller and a displacement sensor 906 for detecting the displacement of the ejector rod 902 are also arranged in the electro-hydraulic brake device 9. The controller is electrically connected to the displacement sensor 906 and the motor 908, respectively. The controller is also electrically connected with a rotation angle sensor on the manpower cylinder 2 and used for obtaining the pedal stroke.

The transmission mechanism comprises a worm gear 905 and a gear rack transmission mechanism 907 which are in transmission fit with each other, a worm of the worm gear 905 is connected with an output shaft of the motor 908, and a worm wheel of the worm gear 905 drives the ejector rod 902 through the gear rack transmission mechanism 907. When the controller driving motor 908 outputs the braking torque, the braking torque is converted into the thrust of the push rod 902 and the push rod 903 of the master cylinder through the worm gear transmission 905 and the rack and pinion transmission 907, so that the piston 910 of the master cylinder is pushed, and the high-pressure brake fluid is delivered to the manual cylinder 2 through the hydraulic pipeline.

The brake control method of the split type electro-hydraulic brake system at least comprises an autonomous brake mode, a brake-by-wire mode, a power-assisted brake mode and a failure backup manual brake mode. The specific control method of each braking mode will be described in detail below.

1. Autonomous braking mode

When other electronic control systems (such as an AEB system) on the automobile send braking requests to the electro-hydraulic braking device 9, the controller of the electro-hydraulic braking device 9 drives the master cylinder 8 through the motor 908 to generate pressure, and outputs brake fluid to the first chamber 238 and the second chamber 239 respectively, and flows to the third chamber 240 through the oil through holes 236 of the

second pistons

219 and 229 for pressure build-up; the brake fluid after pressure build-up flows to the ABS/ESC electromagnetic valve 4, and finally acts on wheel cylinders of a right front brake 5, a left front brake 10, a left rear brake 11 and a right rear brake 6 to realize autonomous braking.

2. Brake by wire mode

When a driver steps on the brake pedal 3, the push rod 217 of the pedal connecting assembly pushes the lever 207 to rotate, the pushing force is transmitted through the damping piston 212 to push the first piston 210, the first piston 210 pushes the piston top rod 223 and the sealing pin 231 to move, and the brake system is in a brake-by-wire mode before the clearance between the sealing pin 231 and the second piston 229 is eliminated. In the brake-by-wire mode, the pedal force is not transmitted to the piston tappet 223 until the clearance S is eliminated, i.e. the brake system is decoupled, the braking force required by the vehicle being generated by regenerative braking of the vehicle' S power motor. At this time, the magnitude of the target braking force depends on the pedal stroke. In the brake-by-wire mode, the pedal stroke is indirectly obtained according to the rotation of the lever 207 detected by a rotation angle sensor arranged on the manual cylinder 2, the target braking force is calculated according to the pedal stroke, and the required braking force is generated by the feedback braking of a power motor of the automobile; when the power battery of the automobile is not allowed to be charged or the feedback braking force of the power motor is lower than the target braking force, the electro-hydraulic brake device 9 controls the motor 908 to drive the master cylinder 8, the master cylinder 8 generates pressure and then outputs brake fluid to the first cavity 238 and the second cavity 239, and the brake fluid directly flows to the third cavity 240 through the oil through holes 236 of the

second pistons

219 and 229 to build pressure; the brake fluid after pressure build-up flows to the ABS/ESC electromagnetic valve 4, and finally acts on wheel cylinders of a right front brake 5, a left front brake 10, a left rear brake 11 and a right rear brake 6, so that brake-by-wire is realized.

3. Boosted braking mode

After the clearance S is eliminated by increasing the stroke of the brake pedal, the brake system works in the boosting mode. The brake deceleration in the boosting mode is larger than 0.3g, at the moment, the regenerative braking is quitted, and the braking force is completely provided by the friction brake. At the moment, the pedal stroke is increased, and the manual brake pushes the piston to generate brake pressure. The controller of the electro-hydraulic brake device controls the motor 908 to output a target torque according to a set brake boosting-pedal stroke target curve, the motor 908 outputs a brake torque, the transmission mechanism is converted into thrust to provide boosting, the thrust and manpower transmitted to the piston top rod 223 push the

second pistons

219 and 229 together, and servo braking is implemented. Specifically, when the driver steps on the brake pedal 3, the push rod 217 of the pedal connecting assembly pushes the lever 207 to rotate, thereby pushing the first piston 210; the first piston 210 pushes the piston mandril 223 and the sealing pin 231 to move, and after the clearance between the sealing pin 231 and the second pistons 219 and 229 is eliminated, the brake system works in an assisted brake mode; at this time, the pedal stroke continues to increase, the controller of the electro-hydraulic brake device 9 controls the motor 908 to drive the main cylinder 8 according to the rotation of the lever 207 detected by the rotation angle sensor arranged on the manual cylinder 2, the main cylinder 8 generates pressure and then outputs brake fluid to the first chamber 238 and the second chamber 239, so that the piston mandril 223 and the seal pin 231 are driven by assistance generated to push the second pistons 219 and 229; the thrust generated by the second pistons 219 and 229 pushes the brake fluid in the third chamber 240 together with the manual force transmitted to the piston rod 223 to build up pressure; the brake fluid after pressure build-up flows to the ABS/ESC electromagnetic valve 4, and finally acts on wheel cylinders of a right front brake 5, a left front brake 10, a left rear brake 11 and a right rear brake 6 to realize boosting braking.

4. Failure backup manual braking mode

When the electro-hydraulic brake device 9 fails, after the driver steps on the brake pedal 3, as long as the pedal stroke is large enough, the brake pressure can be transmitted to the second piston 229 through the pedal connecting assembly, the lever 207, the first piston 210, the piston top rod 223 and the seal pin 231 to generate the brake pressure, so as to implement the manual backup brake. Specifically, the pedal connecting assembly pushes the lever 207 to rotate, so as to push the first piston 210, the piston rod 223 and the seal pin 231 are pushed by the first piston 210, and further the

second pistons

219 and 229, and the brake fluid in the third chamber 240 is pushed by the pushing force generated by the

second pistons

219 and 229 to build pressure; the brake fluid after pressure build-up flows to the ABS/ESC electromagnetic valve 4 and finally acts on wheel cylinders of a right front brake 5, a left front brake 10, a left rear brake 11 and a right rear brake 6 to realize failure backup manual braking.

The above embodiments are merely illustrative of the technical concept and features of the present invention, and the purpose thereof is to enable those skilled in the art to understand the content of the present invention and implement the invention, and not to limit the scope of the invention, and all equivalent changes or modifications made according to the spirit of the present invention should be covered by the scope of the present invention.

Claims

1. The utility model provides a split type electricity liquid braking system, its characterized in that includes first liquid storage pot (1), manpower jar (2), brake pedal (3), ABS/ESC solenoid valve (4), second liquid storage pot (7), master cylinder (8), electricity liquid arresting gear (9) and stopper, wherein:

the brake pedal (3) is connected with the manual cylinder (2) and is used for driving the manual cylinder (2); a first oil inlet is formed in the manual cylinder (2) and communicated with the first liquid storage tank (1), an oil outlet is formed in the manual cylinder (2) and communicated with an oil inlet of the ABS/ESC electromagnetic valve (4) through a hydraulic pipeline, and an oil outlet of the ABS/ESC electromagnetic valve (4) is communicated with a wheel cylinder of the brake through a hydraulic pipeline;

the electro-hydraulic brake device (9) is connected with the master cylinder (8) and is used for driving the master cylinder (8); an oil inlet on the main cylinder (8) is communicated with the second liquid storage tank (7), and an oil outlet on the main cylinder (8) is communicated with a second oil inlet arranged on the manual cylinder (2) through a hydraulic pipeline;

the manual cylinder (2) is provided with a pedal connecting assembly, and the manual cylinder (2) is provided with a first piston cylinder body (209), a second piston cylinder body (226) and an end cover (227) which are fixed with each other; a lever (207) which is pushed by the pedal connecting assembly to rotate, a first piston (210) which is pushed by the lever (207) and a piston top rod (223) which is pushed by the first piston (210) are arranged in the first piston cylinder (209), a first chamber (238) is formed among the first piston cylinder (209), the first piston (210) and the second piston cylinder (226), and the first piston (210) and the piston top rod (223) are movably arranged in the first chamber (238); a second piston (229) pushed by the piston mandril (223) is arranged in the second piston cylinder body (226), the second piston (229) divides the closed space between the second piston cylinder body (226) and the end cover (227) into a second chamber (239) and a third chamber (240), and the front end part of the piston mandril (223) movably extends into the second chamber (239); an oil through hole (236) communicating the second chamber (239) and the third chamber (240) is further formed in the second piston (229), a sealing pin (231) used for abutting against the second piston (229) and sealing the oil through hole (236) is arranged at the front end portion of the piston ejector rod (223), and a gap is formed between the sealing pin (231) and the second piston (229) in an initial state; the third chamber (240) is connected with the first liquid storage tank (1) through the first oil inlet and is connected with the ABS/ESC electromagnetic valve (4) and the first liquid storage tank (1) through the oil outlet; the first chamber (238) and the second chamber (239) are respectively communicated with the master cylinder (8) through the second oil inlet.

2. A split-type electrohydraulic brake system according to claim 1, wherein a piston rod return spring (222) for returning said piston rod (223) is disposed in said first chamber (238), a piston return spring (228) for returning said second piston (229) is disposed in said third chamber (240), and in an initial state, under the action of the pretightening forces of said piston rod return spring (222) and said piston return spring (228), a gap is formed between said seal pin (231) and said second piston (229), and said second chamber (239) and said third chamber (240) are communicated through said oil through hole (236).

3. The split type electro-hydraulic brake system of claim 1, wherein one end of the lever (207) is rotatably connected to the inside of the first piston cylinder (209), a first roller (214) is disposed in the middle of the lever (207) to push the first piston (210), and a second roller (215) is disposed at the other end of the lever (207); one end of the pedal connecting assembly is connected with the brake pedal (3), and the other end of the pedal connecting assembly movably penetrates into the first piston cylinder (209) and is abutted against the second rolling shaft (215) on the lever (207); a sensor magnet (208) is arranged at the end part of one end, far away from the second roller (215), of the lever (207), and a corner sensor for sensing the sensor magnet (208) is arranged on the outer side of the lever (207).

4. A split electro-hydraulic brake system according to claim 3, wherein a damping piston (212) is disposed between the first roller (214) and the first piston (210), one end of the damping piston (212) is installed in a concave hole of the first piston (210), the other end of the damping piston (212) abuts against the first roller (214), and a damping spring (211) is disposed between the damping piston (212) and the first piston (210).

5. The split type electro-hydraulic brake system of claim 2, wherein a cushion block (224), a guide gasket (225) tightly attached to the cushion block (224), and a first leather cup (233) tightly attached to the guide gasket (225) are further arranged in the second piston cylinder (226);

a spring seat (221) is mounted on the first piston (210), one end of the piston mandril (223) is fixed on the spring seat (221), and the other end of the piston mandril passes through the cushion block (224), the guide gasket (225), the first leather cup (233) and the inner through hole of the second piston cylinder body (226) in sequence to enter the second chamber (239); the second piston is also provided with a second leather cup (230).

6. The split type electrohydraulic brake system according to any one of claims 1 to 5, wherein at least two sets of the piston top rod (223) and the second piston (229) are provided, each set is independently provided and is jointly pushed by the first piston (210), and concave holes in which each second piston (229) is located are not communicated with each other.

7. A split electro-hydraulic brake system according to claim 1, wherein the electro-hydraulic brake device (9) comprises a housing (904) and an end cap (901) mounted on the housing (904);

a motor (908), a transmission mechanism connected with the motor (908), a push rod (902) in transmission fit with the transmission mechanism and an end surface (909) propped against by the push rod (902) are arranged in the shell (904), a push rod return spring (911) is arranged between the end surface (909) and the shell (904), and a main cylinder push rod (903) is further arranged on the end surface (909); a master cylinder piston (910) is arranged in the master cylinder (8), and one end of the master cylinder piston (910) is arranged in the length extending direction of the master cylinder push rod (903);

the electro-hydraulic brake device (9) is also internally provided with a controller and a displacement sensor (906) for detecting the displacement of the ejector rod (902), and the controller is electrically connected with the displacement sensor (906) and the motor (908) respectively.

8. The split type electrohydraulic brake system according to claim 7, wherein the transmission mechanism comprises a worm gear (905) and a rack and pinion transmission mechanism (907) which are in transmission fit, a worm of the worm gear (905) is coupled with an output shaft of the motor (908), and a worm wheel of the worm gear (905) drives the ram (902) through the rack and pinion transmission mechanism (907).

9. A split electro-hydraulic brake system according to claim 1, wherein the first reservoir (1) and the second reservoir (7) are a common one.

10. A brake control method of a split type electro-hydraulic brake system according to any one of claims 1 to 9, characterized by comprising the following brake modes:

an autonomous braking mode: when other electric control systems on the automobile send braking requests to the controller of the electro-hydraulic braking device (9), the controller of the electro-hydraulic braking device (9) drives the main cylinder (8) through the motor (908) to generate pressure, brake fluid is respectively output to the first chamber (238) and the second chamber (239), and the pressure is built up when the brake fluid flows to the third chamber (240) through the oil through hole (236) of the second piston (229); the brake fluid after pressure building flows to the ABS/ESC electromagnetic valve (4) and finally acts on a wheel cylinder of the brake to realize autonomous braking;

brake-by-wire mode: when a driver steps on a brake pedal (3), the pedal connecting assembly pushes the lever (207) to rotate, so that the first piston (210) is pushed; the first piston (210) pushes the piston top rod (223) and the sealing pin (231) to move, and before a gap between the sealing pin (231) and the second piston (229) is eliminated, the brake system is in a brake-by-wire mode; under the brake-by-wire mode, the pedal stroke is indirectly obtained according to the rotation of the lever (207) detected by a rotation angle sensor arranged on the manual cylinder (2), the target braking force is calculated according to the pedal stroke, and the required braking force is generated by the feedback braking of a power motor of the automobile; when the power battery of the automobile is not allowed to be charged or the feedback braking force of the power motor is lower than the target braking force, the motor (908) is controlled by the electro-hydraulic braking device (9) to drive the master cylinder (8), the master cylinder (8) generates pressure and then outputs brake fluid to the first chamber (238) and the second chamber (239), and the brake fluid directly flows to the third chamber (240) through the oil through hole (236) of the second piston (229) to build pressure; the brake fluid after pressure building flows to the ABS/ESC electromagnetic valve (4) and finally acts on a wheel cylinder of the brake to realize brake-by-wire;

and (3) an assisted braking mode: when a driver steps on a brake pedal (3), the pedal connecting assembly pushes the lever (207) to rotate, so that the first piston (210) is pushed; the first piston (210) pushes the piston mandril (223) and the seal pin (231) to move, and after a gap between the seal pin (231) and the second piston (229) is eliminated, the brake system works in an assisted brake mode; at the moment, the pedal stroke is continuously increased, a controller of an electro-hydraulic brake device (9) controls a motor (908) to drive a main cylinder (8) according to the rotation of a lever (207) detected by a rotation angle sensor arranged on a manual cylinder (2), the main cylinder (8) generates pressure and then outputs brake fluid to a first chamber (238) and a second chamber (239), and therefore boosting force is generated to drive a piston mandril (223) and a sealing pin (231) so as to push a second piston (229); the thrust generated by the second piston (229) and the manpower transmitted to the piston mandril (223) push the brake fluid in the third chamber (240) together to build pressure; the brake fluid after pressure building flows to the ABS/ESC electromagnetic valve (4) and finally acts on a wheel cylinder of the brake to realize power-assisted braking;

failure backup manual braking mode: when the electro-hydraulic brake device (9) fails, after a driver steps on a brake pedal (3), the pedal connecting assembly pushes the lever (207) to rotate, so that the first piston (210) is pushed, the piston mandril (223) and the seal pin (231) are pushed by the first piston (210), the second piston (229) is further pushed, and the brake fluid in the third chamber (240) is pushed by the pushing force generated by the second piston (229) to build pressure; the brake fluid after pressure build-up flows to the ABS/ESC electromagnetic valve (4) and finally acts on a wheel cylinder of the brake to realize failure backup manual braking.