CN212289794U - Distributed brake system with manpower failure backup and axle pressure equalization functions - Google Patents

Abstract

The utility model provides a distributed braking system with manpower inefficacy backup and axle pressure equalization function belongs to car braking system technical field. The brake system comprises a brake pedal, a manual cylinder, a brake controller and a power supply, and further comprises at least three electric cylinders and electromagnetic valves, wherein the electric cylinders are electrically connected with the brake controller; the two wheel brakes at two ends of the same shaft are communicated through a brake pipeline, an electromagnetic valve is arranged on the brake pipeline, and the electromagnetic valve is electrically connected with the brake controller. The utility model discloses have the dual function of manpower inefficacy backup and axle pressure equalization function, make intelligent driving car motion stationarity good when braking, the reliability is high.

Description

Distributed brake system with manpower failure backup and axle pressure equalization functions

Technical Field

The utility model relates to an automobile brake system technical field, concretely relates to distributing type braking system with manpower became invalid and is backed up and axle pressure equalization function.

Background

The automobile brake system is closely related to the automobile driving safety. In a conventional hydraulic brake system for an automobile, a driver applies a braking pressure to wheel cylinders of brakes of respective wheels by pressing a brake pedal, thereby braking and decelerating the automobile. Intelligent automotive systems such as Advanced Driving Assistance Systems (ADAS) and Automatic Driving Systems (ADS) require that the braking system be capable of applying autonomous braking to the vehicle, i.e., applying braking to some or all of the wheels without depressing the brake pedal. At present, most of brake systems capable of implementing autonomous braking adopt electric power assistance, and brake control devices such as a brake pedal are reserved. With the development of unmanned logistics distribution vehicles, an autonomous braking system applicable to ADS, which does not require a brake operating device, has been proposed.

Distributed braking systems have many advantages and are considered the direction of development for the next generation of braking systems. The braking force of all wheels can be independently controlled and adjusted, so that the distributed braking system has the advantages of flexible control, high braking force control precision and the like; the actuating mechanism of the distributed braking system is close to the wheel brake, so that the braking response is fast and the dynamic characteristic of the braking pressure is good; compared with the traditional double-loop brake system, the four-wheel independent brake distributed brake system is equivalent to a four-loop system, and the reliability of the system is further improved. In most service braking conditions, two front wheels and two rear wheels respectively require consistent braking pressure, and in order to realize the function, the control difficulty is additionally increased, and the effect is also not ideal.

On the other hand, electric vehicles are also receiving wide attention from various countries. There are several countries that have published a schedule of prohibited fuel vehicles in sequence around the world in 2018, for example the netherlands and norway will prohibit fuel vehicles in 2025, india will prohibit the sale of fuel vehicles in 2030, and the uk and france will also prohibit the sale of fuel vehicles in full in 2040. China will also stop selling fuel cars completely in 2035. The automobile with the new energy possibly replacing the fuel automobile is a new energy automobile such as an electric automobile, a fuel cell automobile and the like. In order to increase the endurance mileage of a new energy automobile, braking energy recovery is commonly adopted. However, the existing brake system does not satisfy the requirement of braking energy recovery, i.e., cannot solve the contradiction between the brake pedal feel and the braking energy recovery. The reason for this is that existing brake systems are not decoupled at all.

Therefore, there is a need to provide a new distributed braking system to solve the above problems.

SUMMERY OF THE UTILITY MODEL

The utility model aims at overcoming prior art and lacking the defect of automatically controlled inefficacy safeguard function and axial pressure equalization function, providing a distributed autonomous braking system of function and axial pressure equalization function is protected to utensil.

In order to achieve the above object, the present invention provides a distributed brake system with manpower failure backup and axle pressure equalization functions, including a brake pedal, a manpower cylinder, a brake controller and a power supply, characterized in that, the system further includes at least three electric cylinders and electromagnetic valves electrically connected with the brake controller, the electric cylinders are respectively connected with the liquid discharge holes of the manpower cylinder through brake pipelines, the electric cylinders are connected to the wheel brakes of the same number on the vehicle in a one-to-one correspondence manner, and each electric cylinder and a corresponding wheel brake form a brake loop; the two wheel brakes at two ends of the same shaft are communicated through a brake pipeline, an electromagnetic valve is arranged on the brake pipeline, and the electromagnetic valve is electrically connected with the brake controller; the brake controller is respectively connected with the pedal stroke sensor and the pressure sensor through signal wires and is used for measuring the stroke of the brake pedal and the pressure of the manual cylinder.

Further, the wheel brakes include a first wheel brake, a second wheel brake, a third wheel brake, and a fourth wheel brake; the solenoid valves include a first solenoid valve disposed on a brake line between the first wheel brake and the second wheel brake, and a second solenoid valve disposed on a brake line between the third wheel brake and the fourth wheel brake; the first electromagnetic valve and the second electromagnetic valve are electrically connected with the brake controller.

Further, the electric cylinder includes: an electric cylinder body; the electric cylinder body is fixedly connected with the shell, the shell is provided with a motor, the motor drives the piston to slide through a pushing device, and the pushing device comprises a pushing rod driven by the motor; a through hole is formed in the middle of the piston, and the push rod movably penetrates through the through hole and forms an oil liquid channel for oil supply liquid to pass through with the inner side wall of the through hole; the push rod is provided with an input valve and an output valve on two sides of the through hole respectively, and a return elastic piece is arranged between the end part of the push rod penetrating through the through hole and the electric cylinder body; the electric cylinder body is provided with the oil inlet and the oil outlet on two sides of the piston respectively.

Furthermore, the pushing device is a ball screw pair comprising a nut and a pushing rod, and the pushing rod is a screw rod; the screw rod is provided with a first conical surface and a second conical surface which are respectively arranged on two sides of the through hole and are matched with the piston to open and close the oil passage; the first conical surface is matched with a third conical surface arranged on the piston to form the input valve, and the second conical surface is matched with a fourth conical surface arranged on the piston to form the output valve; the first conical surface tapers toward the piston and the second conical surface tapers away from the piston; when the return elastic piece is in a pre-pressing state, the output valve is closed, and the input valve is opened.

Further, the electric cylinder includes an electric cylinder body; the electric cylinder body is fixedly connected with the shell, the shell is provided with a motor, the motor drives the piston to slide through a pushing device, and the pushing device comprises a pushing rod driven by the motor; a through hole is formed in the middle of the piston, and the push rod movably penetrates through the through hole and forms an oil liquid channel for oil supply liquid to pass through with the inner side wall of the through hole; the push rod is provided with an input valve and an output valve on two sides of the through hole respectively, and a return elastic piece is arranged between the end part of the push rod penetrating through the through hole and the electric cylinder body; the electric cylinder body is provided with the oil inlet and the oil outlet on two sides of the piston respectively.

Furthermore, the interior of the shell is of a cylindrical hollow structure and comprises a first cylindrical cavity, a second cylindrical cavity and a third cylindrical cavity, the inner diameters of the first cylindrical cavity, the second cylindrical cavity and the third cylindrical cavity are sequentially increased, a partition surface is arranged between the first cylindrical cavity and the second cylindrical cavity, and a through hole for the screw rod to pass through is formed in the partition surface; a shaft shoulder is formed between the second cylindrical cavity and the third cylindrical cavity, the nut is rotatably arranged in the third cylindrical cavity, and one end of the nut is fixed on the shaft shoulder through a bearing; one end of the shell, which is close to the piston, extends outwards in the radial direction to form a boss, and the boss is in sealing fit with and fixedly connected with the opening of the electric cylinder body.

Further, an annular bottom surface is arranged between the first conical surface and the second conical surface of the screw rod, and the diameter of the annular bottom surface is smaller than the inner diameter of the through hole.

Further, the screw rod is provided with a guide groove, and one end of a guide pin fixed in the shell is inserted into the guide groove.

Further, the manual cylinder includes:

the brake pedal comprises a liquid storage tank, a manual cylinder body communicated with the liquid storage tank, a piston assembly arranged in the manual cylinder body in a sliding mode and a rack for driving the piston assembly to slide, wherein the rack is connected with the brake pedal through a push rod, and an idle stroke is formed between the rack and the piston assembly; the manual cylinder further comprises an end cover connected with the manual cylinder body, a gear meshed with the rack is further arranged in the end cover, and the gear rotates around the axis of the gear and outputs a corner signal through the pedal stroke sensor.

Further, the piston assembly includes first preceding piston and the preceding piston of second that sets up along its slip direction, with first preceding piston be connected and with rack complex first back piston and be used for connecting the piston is followed to the second of piston and first back piston, first preceding piston, first back piston and be formed with first cavity between the inner wall of manpower cylinder body, first preceding piston, second back piston and be formed with the second cavity between the inner wall of manpower cylinder body, piston, second preceding piston and the manpower cylinder body are formed with the third cavity between the inner wall of manpower cylinder body, before the second piston with be formed with the fourth cavity between the inner wall of manpower cylinder body.

Further, the manpower jar cylinder body has seted up: the liquid storage tank is communicated with a first liquid supply hole of the first cavity, the liquid storage tank is communicated with a first compensation hole of the second cavity, the liquid storage tank is communicated with a second liquid supply hole of the third cavity, the liquid storage tank is communicated with a second compensation hole of the fourth cavity, the liquid storage tank is communicated with a first liquid discharge hole of the second cavity, and the second liquid discharge hole is communicated with the fourth cavity.

Further, a first front leather cup is arranged on the first front piston, a second front leather cup is arranged on the second front piston, a first elastic piece is arranged between the first front piston and the second rear piston, a second elastic piece is arranged between the second front piston and the inner wall of the manual cylinder body, the first rear piston is connected with the second rear piston in a sliding mode, when the first elastic piece is in a prepressing state, the first front leather cup is located between the first liquid supply hole and the first compensation hole, and when the second elastic piece is in a prepressing state, the second front leather cup is located between the second liquid supply hole and the second compensation hole; the elastic coefficient of the first elastic member is greater than the elastic coefficient of the second elastic member.

Furthermore, an elastic piece is arranged between the rack and the inner wall of the manual cylinder body, one side, facing the rack, of the first rear piston is provided with an insertion hole, and the rack is provided with a butting part which is in insertion fit with the insertion hole; when the elastic piece is in a prepressing state, the idle stroke exists between the end surface of the abutting part and the bottom surface of the jack; the jack is a cylindrical hole, the bottom surface of the cylindrical hole is in an inwards concave spherical shape, the abutting part is a cylinder, and the end face is in a convex spherical shape.

Furthermore, the number of the electric cylinders is four, and the electric cylinders comprise a first electric cylinder, a second electric cylinder, a third electric cylinder and a fourth electric cylinder, wherein the first electric cylinder is communicated with the first wheel brake through a brake pipeline to form a first brake loop, the second electric cylinder is communicated with the second wheel brake through a brake pipeline to form a second brake loop, the third electric cylinder is communicated with the third wheel brake through a brake pipeline to form a third brake loop, and the fourth electric cylinder is communicated with the fourth wheel brake through a brake pipeline to form a fourth brake loop.

The utility model comprises a brake-by-wire mode, a power-assisted brake mode, an autonomous brake mode, a failure protection brake mode and a failure backup manual brake mode;

and in the brake-by-wire mode, when the brake pedal is stepped on, the idle stroke is gradually reduced. When the idle stroke is not completely eliminated, the pedal force cannot be transmitted to the piston assembly, namely the brake pedal is in a decoupling state with the manual cylinder and each wheel brake.

Brake control method and working process in brake-by-wire mode

When the brake pedal is stepped on, the idle stroke is gradually reduced. When the idle stroke is not completely eliminated, the pedal force cannot be transmitted to the piston assembly, namely the brake pedal is in a decoupling state with the manual cylinder and each wheel brake. The brake controller receives the signal of the pedal stroke sensor, calculates the required braking force and the target current of the motor, sends an instruction to the motor to rotate the motor and output torque, and drives the ball screw pair through the coupler to enable the screw to translate leftwards; after the thrust of the screw rod overcomes the pre-pressure of the return elastic piece, the input valve is closed, the output valve is opened, and the screw rod and the piston move together along the axial direction to enable the output pressure to reach the brake inlets of the wheels through the oil outlets and the brake pipelines; if the brake pedal is released, the pedal stroke measured by the pedal stroke sensor is reduced in the process, the brake controller reduces the target current of the motor according to the pedal stroke, the torque of the motor and the thrust acting on the screw rod and the piston are reduced along with the target current, and the volume of the oil outlet cavity is increased so that the pressure of the brake is reduced; if the brake pedal is completely released, the brake is released, the pedal stroke measured by the pedal stroke sensor is zero, the brake controller stops the motor according to the pedal stroke, the screw rod and the piston move reversely to the initial position under the action of the return elastic piece, the output valve is closed, the input valve is opened, and the brake of the brake is released. And in the braking process, the two electromagnetic valves are normally opened so as to maintain the hydraulic balance between the wheel brakes at the two coaxial ends and the corresponding brake pipelines.

Brake control method and working process in power-assisted brake mode

When the travel of the brake pedal is increased to eliminate idle travel and further increase the travel of the brake pedal, pedal force can be directly transmitted to a piston assembly of the manual cylinder and the manual cylinder has pressure output, and the pressure is finally applied to a wheel brake through a brake pipeline; at the beginning stage of the power-assisted braking, the braking controller drives the motor to work to drive the ball screw pair to apply thrust to the screw, and overcomes the pre-pressure of the return elastic piece to close the input valve and open the output valve; the thrust transmitted to the screw rod by the motor acts on the piston through the input valve in a closed state; at the moment, the force acting on the piston comprises pedal force transmitted to the oil inlet cavity through a manual cylinder and a brake pipeline and also comprises motor force transmitted to the screw rod, the piston moves along the axial direction under the combined action of the pedal force and the motor torque, and the generated pressure is output to a corresponding brake through the brake pipeline, so that the power-assisted braking is realized; if the brake pedal is released in the power-assisted braking mode, the pedal force is reduced, the pedal stroke measured by the pedal stroke sensor is reduced, and the brake controller reduces the target current of the motor according to the reduced pedal force, so that the brake pressure is reduced; and if the brake pedal is released enough in the power-assisted braking mode to cause the idle stroke to be larger than 0, the system is switched from the power-assisted braking mode to the brake-by-wire mode. And in the braking process, the two electromagnetic valves are normally opened so as to maintain the hydraulic balance between the wheel brakes at the two coaxial ends and the corresponding brake pipelines.

Brake control method and working process in autonomous brake mode

When the brake controller receives a brake request from other electronic control systems, the system works in an autonomous braking mode. The specific working process in the autonomous braking mode is as follows: the brake controller calculates the target torque of the motor according to the received brake requests from other electric control systems, and then respectively sends torque commands to the motor to control each electric cylinder to work, so that the brake is automatically braked; the control in the brake-by-wire mode depends on the magnitude of the pedal stroke, and the control in the autonomous braking mode depends on the braking request from other electronic control systems, except that the working process in the two modes is the same. And in the braking process, the two electromagnetic valves are normally opened so as to maintain the hydraulic balance between the wheel brakes at the two coaxial ends and the corresponding brake pipelines.

Brake control method and working process in failure protection brake mode

When one brake circuit fails, the system operates in a fail-safe braking mode. When the brake controller detects that one brake circuit of the system fails, the failure protection brake can be implemented by applying a target torque larger than that of the motor of the non-failed brake circuit when the system normally works; at this time, the brake controller first calculates a target assist force or a target braking force according to a pedal stroke sensor signal or a braking request from another electronic control system, then distributes the target assist force or the target braking force to each wheel brake of the non-failed brake circuit, and then controls the electric cylinder output torque of the non-failed brake circuit, thereby realizing fail-safe braking. In determining the target assistance or target braking force of the respective wheel brake in the fail-safe braking mode, the maximum torque of the respective electric machine should not be exceeded or, according to a specific embodiment and with reference to relevant regulatory requirements, be determined. And in the braking process, the two electromagnetic valves are normally opened so as to maintain the hydraulic balance between the wheel brakes at the two coaxial ends and the corresponding brake pipelines.

The brake release in the fail safe brake mode is the same as the autonomous brake mode and the like.

Working process in failure manpower backup braking mode

If the electric control braking function of the braking system is completely lost due to any fault, namely, the four braking circuits cannot generate effective braking action by depending on the work of the motor, the manual backup braking can be implemented. In the failure manual backup braking mode, if a driver steps on a brake pedal, pedal force pushes a piston assembly of the manual cylinder through the supporting pin, the push rod and the rack, and braking pressure established by the manual cylinder is transmitted to the oil inlet cavity through a braking pipeline. Because the motor does not work, the output valve of the electric cylinder is closed, and therefore the oil inlet cavity and the oil outlet cavity of the electric cylinder are in a brake fluid isolation state; at this time, the piston moves due to the pressure from the manual cylinder in the oil inlet cavity, and the pressure generated by the oil outlet cavity is output to each wheel brake through the brake pipeline, so that manual backup braking is applied. And in the braking process, the two electromagnetic valves are normally opened so as to maintain the hydraulic balance between the wheel brakes at the two coaxial ends and the corresponding brake pipelines.

Due to the adoption of the technical scheme, the utility model discloses following beneficial effect has:

1. the utility model has a distributed brake system, the motor directly drives the piston of the electric cylinder through the transmission device, the pressure building time is short, and the brake response is fast;

2. the utility model has a distributed brake system, eliminates a manual brake device, and has simple structure, low cost and convenient arrangement;

3. the utility model adopts the distributed autonomous braking system with the axial pressure balancing function, which can balance the axial pressure in the system, so the reliability of the braking system is high and the failure protection capability is strong;

4. the utility model discloses a distributed autonomous braking system with backup safeguard function of manpower inefficacy provides the backup braking of manpower inefficacy under the braking system leads to its automatically controlled braking function to lose completely because of any trouble, has further improved braking system's reliability and driving safety nature.

5. The utility model discloses a manpower jar small stroke drive-by-wire makes braking system support the demand of braking energy recovery maximize under the prerequisite of not influencing driver's brake pedal sensation.

Drawings

Fig. 1 is a schematic structural diagram of a distributed brake system with a manpower failure backup and axle pressure equalization function according to the present invention;

fig. 2 is a schematic structural diagram of a distributed brake system with a manpower failure backup and axle pressure equalization function according to the present invention;

FIG. 3 is a schematic structural view of the man-powered cylinder and the operating device thereof;

fig. 4 is a schematic structural view of the electric cylinder of the present invention;

FIG. 5 is an enlarged view taken at A in FIG. 4;

fig. 6 is an enlarged view of the opening F2 of the present invention at a;

the parts in the figures are numbered: 1-brake pedal; 2-a bearing pin; 3-pedal stroke sensor; 4-a manual vat; 5-a pressure sensor; 6-a power supply; 7-a brake controller; 8 a-a first electric cylinder; 8 b-a second electric cylinder; 8 c-a third electric cylinder; 8 d-a fourth electric cylinder; 9-a first wheel brake; 10-a second wheel brake; 11-a third wheel brake; 12-a fourth wheel brake; 13 a-a first solenoid valve; 13 b-a second solenoid valve;

401-push rod; 402-a nut; 403-rack bar; 404-an end cap; 405-a gear; 406-a resilient member; 407-a spacing pin; 408-a first cylinder; 409-a first rear piston; 410-a first back cup; 411-sealing ring; 412-first front cup; 413-a first front piston; 414-front bolt; 415-a first elastic member; 416-a second rear piston; 417-second rear leather cup; 418-a second front piston; 419-second front leather cup; 420-rear bolt; 421-a second elastic member; 422-a second cylinder; 423-liquid storage tank; b-a jack; c-a top-butting portion; s-idle stroke; a1 — first cavity; a 2-third cavity; d1-a second cavity; d2-fourth cavity; b1 — first supply hole; b2 — second feed hole; c1 — first compensation hole; c2 — second compensation hole; e1-first drainage hole; e2-second drain hole;

801-electric machine; 802-coupling; 803-a retainer ring; 804-a nut; 805-bearings; 806-screw rod; 807-O-rings; 808-an oil inlet; 809-an oil inlet cavity; 810-guide pins; 811-sealing ring; 812-a leather cup; 813-piston; 814-an oil outlet; 815-return elastic member; 816-oil outlet chamber; 817-electric cylinder block; 818-a housing; v1-first conical surface; v2-second conical surface; v3-third cone; v4-fourth conical surface; v5-circular bottom surface; f1-input valve; f2-output valve; d-a cylindrical surface.

In fig. 1 and 2, the signal lines and the power supply lines are indicated by broken lines; the thick solid line represents the brake pipe.

Detailed Description

As shown in fig. 1, the utility model provides a distributed braking system with manpower inefficacy backup and axle pressure equalization function mainly includes brake pedal 1, supporting pin 2, footboard stroke sensor 3, manpower jar 4, pressure sensor 5, brake controller 7 and power 6, still include at least three electronic jar of being connected with brake controller 7 electricity, electronic jar links through the outage of brake pipe way with manpower jar 4 respectively, the same quantity's on the car wheel brake is connected to electronic jar one-to-one, and every electronic jar forms a braking circuit with a wheel brake that corresponds. The brake controller 7 is respectively connected with the pedal stroke sensor 3 and the pressure sensor 5 through signal lines and is used for measuring the stroke of the brake pedal 1 and the pressure of the manual cylinder 4; the brake pedal 1 is connected with a manual cylinder 4 through a supporting pin 2; the brake controller 7 is connected to the power source 6 and the motor 801 of the electric cylinder through power lines. The two wheel brakes at two ends of the same shaft are communicated through a brake pipeline, and the brake pipeline is provided with an electromagnetic valve; the solenoid valves include a first solenoid valve 13a disposed on a brake line between the first wheel brake 9 and the second wheel brake 10, and a second solenoid valve 13b disposed on a brake line between the third wheel brake 11 and the fourth wheel brake 12; the first solenoid valve 13a and the second solenoid valve 13b are electrically connected to the brake controller 7.

There are various connection modes of the manual cylinder 4 and the electric cylinder. Referring to fig. 1, as one of the ways, the manual cylinder 4 is connected with one of the circuits to which the first wheel brake 9 and the fourth wheel brake 12 of the automobile are coupled, and the other circuit of the manual cylinder 4 is connected with the electric cylinder to which the second wheel brake 10 and the third wheel brake 11 of the automobile are coupled, i.e., an X-type circuit. Referring to fig. 2, as a second mode, one circuit of the manual cylinders 4 is connected to the electric cylinders to which the two front wheel brakes of the vehicle are coupled, and the other circuit of the manual cylinders 4 is connected to the electric cylinders to which the two rear wheel brakes of the vehicle are coupled, i.e., an H-shaped circuit is formed. The loop of the two forms can reach the purpose of the utility model.

In this embodiment, there are 4 electric cylinders, which are a first electric cylinder 8a, a second electric cylinder 8b, a third electric cylinder 8c and a fourth electric cylinder 8 d; in other embodiments, other numbers of electric cylinders, such as 3 or 6, may be provided. In this embodiment, the first electric cylinder 8a is communicated with the first wheel brake 9 through a brake pipe to form a first brake circuit, the second electric cylinder 8b is communicated with the second wheel brake 10 through a brake pipe to form a second brake circuit, the third electric cylinder 8c is communicated with the third wheel brake 11 through a brake pipe to form a third brake circuit, and the fourth electric cylinder 8d is communicated with the fourth wheel brake 12 through a brake pipe to form a fourth brake circuit; the first electric cylinder 8a, the second electric cylinder 8b, the third electric cylinder 8c and the fourth electric cylinder 8d are respectively connected with a drain hole of the manual cylinder 4 through brake pipelines and are respectively connected with the brake controller 7 through signal lines.

The electric cylinders are coupled to the same number of wheel brakes on the vehicle in a one-to-one correspondence, and each electric cylinder forms a brake circuit with a corresponding one of the wheel brakes. The number of the electric cylinders in the utility model is in one-to-one correspondence with the number of the corresponding wheel brakes, for example, three wheel brakes have corresponding three electric cylinders, which is similar to a tricycle; the four wheel brakes have corresponding four electric cylinders, or six-wheel vehicle has six electric cylinders. In the present embodiment, four wheel brakes and four electric cylinders are employed.

In this embodiment, the first electric cylinder 8a, the second electric cylinder 8b, the third electric cylinder 8c, and the fourth electric cylinder 8d have the same structure as that shown in fig. 4, and include a motor 801, a coupling 802, a retainer 803, a nut 804, a bearing 805, a lead screw 806, an O-ring 807, a guide pin 810, a seal ring 811, a cup 812, a piston 813, a return elastic member 815, an electric cylinder 817, and a housing 818.

As shown in fig. 4, the electric cylinder includes an electric cylinder block 817; the electric cylinder 817 is fixedly connected with the housing 818, the housing 818 is provided with a motor 801, the motor 801 drives the piston 813 to slide through a pushing device, and the pushing device comprises a pushing rod driven by the motor 801; a through hole is formed in the middle of the piston 813, and the push rod movably penetrates through the through hole and forms an oil liquid channel for oil to pass through with the inner side wall of the through hole; an input valve F1 and an output valve F2 are respectively arranged on two sides of the push rod positioned in the through hole, and a return elastic member 815 is arranged between the end part of the push rod penetrating through the through hole and the electric cylinder 817; an oil inlet 808 and an oil outlet 814 are respectively arranged on two sides of the piston 813 of the electric cylinder block 817.

In this embodiment, the resilient return element 815 is a return spring.

In this embodiment, the pushing device is a ball screw pair including a nut 804 and a pushing rod, the pushing rod is a screw 806; the screw rod 806 is provided with a first conical surface V1 and a second conical surface V2 which are respectively matched with the piston 813 to open and close the oil passage at two sides of the through hole; as shown in fig. 6 and 5, the first conical surface V1 cooperates with a third conical surface V3 provided on the piston 813 to form an inlet valve F1, and the second conical surface V2 cooperates with a fourth conical surface V4 provided on the piston 813 to form an outlet valve F2; the first conical surface V1 tapers towards the piston 813, and the second conical surface V2 tapers away from the piston 813; when the return elastic member 815 is in a pre-stressed state, the output valve F2 is closed, and the input valve F1 is opened.

In this embodiment, the length of the cylindrical surface D between the input valve F1 and the output valve F2 is 0.5-1mm longer than the length of the cylindrical surface of the through hole of the piston 813.

In this embodiment, the outer diameters of the first conical surface V1 and the second conical surface V2 are larger than the diameter of the through hole of the piston 813, so that the screw rod 806 can be divided into two sections and connected through threads, and the piston 813 is clamped between the first conical surface V1 and the second conical surface V2 and locked in threaded connection during installation.

In this embodiment, the screw 806 has an annular bottom V5 between the first conical surface V1 and the second conical surface V2, and the diameter of the annular bottom V5 is smaller than the inner diameter of the through hole.

In this embodiment, the inside of the housing 818 is a cylindrical hollow structure, and includes a first cylindrical cavity, a second cylindrical cavity and a third cylindrical cavity, the inner diameters of which are sequentially increased, a partition surface is disposed between the first cylindrical cavity and the second cylindrical cavity, and a through hole for the screw rod 806 to pass through is formed on the partition surface; a shaft shoulder is formed between the second cylindrical cavity and the third cylindrical cavity, the nut 804 is rotatably arranged in the third cylindrical cavity, and one end of the nut 804 is fixed on the shaft shoulder through a bearing 805; the end of housing 818 adjacent to piston 813 extends radially outwardly to form a boss that sealingly engages and is fixedly attached to the opening of cylinder 817.

In this embodiment, the inner wall between the first cylindrical cavity and the second cylindrical cavity extends radially inward to form a partition surface, and the retainer 803 is installed on the third cylindrical cavity.

In this embodiment, the electric cylinder 817 is a hollow cylinder with an open right end.

In this embodiment, a motor 801 is mounted on the right end face of the housing 818, and the output shaft of the motor 801 is coupled to a nut 804 through a coupling 802; is supported by a ball screw pair through two bearings 805 and is axially positioned by a shoulder in the bore of housing 818 and a retainer 803.

In this embodiment, the screw rod 806 is provided with a guide slot, one end of a guide pin 810 fixed in the housing 818 is inserted into the guide slot, and the guide pin 810 limits the rotation of the screw rod 806, so the operation mode of the ball screw pair is that the nut 804 rotates and the screw rod 806 translates.

In this embodiment, a cup 812 with a one-way sealing function is mounted in an annular groove on the outer circumference of piston 813, and is supported with piston 813 in the inner bore of electric cylinder block 817 to be axially slidable.

In this embodiment, an oil chamber 816 is formed between the left end surface of the piston 813 and the interior of the electric cylinder 817, the pre-pressure of the return elastic member 815 acts on one end of the screw rod 806, and the output valve F2 is closed, and the piston 813 is pressed against the end surface of the housing 818; an oil inlet cavity 809 is formed between the right end face of the piston 813 and the first cylindrical cavity of the housing 818, the left end face of the partition surface and the outer surface of the screw rod 806.

As shown in fig. 3, the manual cylinder 4 includes a fluid reservoir 423, a manual cylinder body communicated with the fluid reservoir 423, a piston assembly slidably disposed in the manual cylinder body, and a rack 403 for driving the piston assembly to slide, the rack 403 is connected to the brake pedal 1 through a push rod 401, and the push rod 401 is connected to the brake pedal 1 through a support pin 2. In this embodiment, the push rod 401 is connected to the rack 403 by a nut 402. There is an idle stroke S between the rack 403 and the piston assembly.

The manual cylinder 4 further comprises an end cover 404 connected with a cylinder body of the manual cylinder, a gear 405 meshed with the rack 403 is further arranged in the end cover 404, and rotation of the gear 405 around the axis of the gear outputs a rotation angle signal through the pedal stroke sensor 3. In this embodiment, the manual cylinder includes a first cylinder 408 and a second cylinder 422, which are fixedly connected and communicated with each other, and a sealing ring 411 is disposed at the connection.

Specifically, the piston assembly includes a first front piston 413 and a second front piston 418 arranged along a sliding direction thereof, a first rear piston 409 connected to the first front piston 413 and engaged with the rack 403, and a second rear piston 416 for connecting the second front piston 418 and the first rear piston 409. The first front piston 413 and the first rear piston 409 are fixedly connected through a front bolt 414, and the first front piston 413 and the first rear piston 409 move synchronously. The second front piston 418 and the second rear piston 416 are fixedly connected by a rear bolt 420, and the second front piston 418 and the second rear piston 416 move synchronously. The first rear piston 409 and the second rear piston 416 should be slidably connected, and in this embodiment, the first rear piston 409 is provided with a protruding rod, and the second rear piston 416 is provided with a hole for slidably fitting the rod.

A first cavity A1 is formed among the inner walls of the first front piston 413, the first rear piston 409 and the first cylinder 408, a second cavity D1 is formed among the inner walls of the first front piston 413, the second rear piston 416 and the second cylinder 422, a third cavity A2 is formed among the inner walls of the second rear piston 416, the second front piston 418 and the second cylinder 422, and a fourth cavity D2 is formed between the inner walls of the second front piston 418 and the second cylinder 422;

the manpower cylinder body is provided with: a first liquid supply hole B1 communicated with the liquid storage tank 423 and the first cavity A1, a first compensation hole C1 communicated with the liquid storage tank 423 and the second cavity D1, a second liquid supply hole B2 communicated with the liquid storage tank 423 and the third cavity A2, a second compensation hole C2 communicated with the liquid storage tank 423 and the fourth cavity D2, a first liquid discharge hole E1 communicated with the second cavity D1 and a second liquid discharge hole E2 communicated with the fourth cavity D2;

a first front leather cup 412 is arranged on the first front piston 413, a second front leather cup 419 is arranged on the second front piston 418, a first elastic piece 415 is arranged between the first front piston 413 and the second rear piston 416, a second elastic piece 421 is arranged between the second front piston 418 and the inner wall of the manual cylinder body, the first rear piston 409 is in sliding connection with the second rear piston 416, when the first elastic piece 415 is in a prepressing state, the first front leather cup 412 is positioned between the first liquid supply hole B1 and the first compensation hole C1, and when the second elastic piece 421 is in a prepressing state, the second front leather cup 419 is positioned between the second liquid supply hole B2 and the second compensation hole C2. Meanwhile, the cylinder body of the manual cylinder is further provided with a limit pin 407, and when the first elastic member 415 and the second elastic member 421 are in a pre-pressing state, the first rear piston 409 abuts against the limit pin 407. The first rear piston 409 and the second rear piston 416 are respectively provided with a first rear cup 411 and a second rear cup 417.

In a preferred embodiment, the elastic modulus of the first elastic member 415 is greater than the elastic modulus of the second elastic member 421. An elastic member 406 is disposed between the rack 403 and the inner wall of the cylinder body, and in this embodiment, the elastic member 406 is a conical spring. One side of the first rear piston 409 facing the rack 403 is provided with an insertion hole B, and the rack 403 is provided with a top abutting part C in insertion fit with the insertion hole B; when the elastic member 406 is in a pre-pressed state, an idle stroke S exists between the end surface of the abutting portion C and the bottom surface of the insertion hole B. The specific design is that the insertion hole B is a cylindrical hole, the bottom surface of the cylindrical hole is in a concave spherical surface shape, the abutting part C is a cylinder, and the end surface is in a convex spherical surface shape. The distance between the spherical surface of the abutting part C moving to contact with the concave spherical surface becomes the idle stroke S.

In this embodiment, the brake controller 7 is also connected to other electronic control systems (such as an anti-lock brake system or a smart car control system) shown in fig. 1 through a signal line.

In the present embodiment, the brake controller 7 controls the motor 801 to operate to output a brake pressure to the corresponding brake in accordance with the displacement measured by the pedal stroke sensor 3 or a brake request from another electronic control system. The driver braking demand is typically reflected by the pedal stroke sensor 3.

In this embodiment, the first solenoid valve 13a and the second solenoid valve 13b are both normally open solenoid valves, and the oil pressure in the brake pipe is adjusted by controlling the opening and closing of each solenoid valve, so as to dynamically select whether the brake pressures of the two coaxial wheel brakes are balanced.

The utility model discloses the theory of operation of the solenoid valve that axis pressure balance function realized is: under the action of the motor 801, the piston 812 is forced leftwards, when the leather cup 813 blocks the compensation hole C, high pressure is built in the first cavity D, low pressure is built in the second cavity a, and oil is discharged through the liquid discharge hole E to brake the automobile.

A pressure fluctuation is output by the forward rotation and the reverse rotation of the motor 801, so that the oil pressure in the brake pipeline can have relative high pressure and low pressure, namely, when the motor 801 rotates forward, high-pressure oil is formed in the brake pipeline, and when the motor 801 rotates reversely, low-pressure oil is formed in the brake pipeline. In the braking process, the two electromagnetic valves are normally opened so as to maintain the hydraulic balance between the wheel brakes at the two coaxial ends and the corresponding brake pipelines; when the hydraulic pressure balance is not required to be maintained in certain specific conditions, for example, in a turning state and the like, the brake controller 7 receives an electric signal and controls the electromagnetic valves to be closed, the brake pipeline between the two wheel brakes at the two ends of the same shaft is disconnected, and the hydraulic pressures in the two wheel brakes are not maintained in balance any more.

In this embodiment, the utility model discloses a distributed braking system with multiple mode mainly includes following several kinds of modes, i.e. brake-by-wire, helping hand braking, autonomic braking, failure protection braking and the backup braking of the manpower that became invalid etc.. The operation of the brake system in each of the operating modes is explained below.

1. Brake control method and working process in brake-by-wire mode

As shown in fig. 3, when the stroke of the brake pedal 1 is small, the system operates in the brake-by-wire mode. When the brake pedal 1 is depressed, the idle stroke S (see fig. 3) is gradually reduced. When the idle stroke S is not completely eliminated, the pedal force is not transmitted to the piston assembly, i.e. the brake pedal 1 is decoupled from the manual cylinder 4 and the wheel brakes.

In the brake-by-wire mode with a small pedal stroke, the braking forces required by the first wheel brake 9, the second wheel brake 10, the third wheel brake 11, and the fourth wheel brake 12 are generally provided by the first electric cylinder 8a, the second electric cylinder 8b, the third electric cylinder 8c, and the fourth electric cylinder 8 d. The specific working process is as follows: the brake controller 7 receives the signal of the pedal stroke sensor 3, calculates the required braking force and the target current of the motor 801, sends an instruction to the motor 801 to rotate the braking force and the target current and output torque, and drives the ball screw pair to make the screw 806 move leftwards through the coupler 802; after the thrust of the screw 806 overcomes the pre-pressure of the return elastic member 815, the first conical surface V1 is attached to the third conical surface V3, the second conical surface V2 is spaced from the fourth conical surface V4, at this time, the input valve F1 is closed, the output valve F2 is opened, the screw 806 moves along the axial direction together with the piston 813, so that the volume of the oil outlet cavity 816 is reduced, and then the output pressure is delivered to the inlets of the wheel brakes through the oil outlet 814 and the brake pipeline; meanwhile, the volume of the oil inlet cavity 809 is increased, and the required brake fluid is supplemented to the oil inlet cavity 809 through the compensation hole 412, the front cavity of the manual cylinder 4, the liquid discharge hole, the brake pipeline and the oil inlet 808 by the liquid storage tank 417; if the brake pedal 1 is released, the pedal stroke measured by the pedal stroke sensor 3 is reduced in the process, the brake controller 7 accordingly reduces the target current of the motor 801, the torque of the motor 801 and the thrust acting on the screw rod 806 and the piston 813 are reduced, because the end surface of the piston 813 on the oil outlet cavity 816 side is subjected to larger force at the moment, the piston 813 moves to the right along the axial direction together with the screw rod 806, the volume of the oil outlet cavity 816 is increased, the brake pressure is reduced, the nut 804, the coupling 802 and the motor 801 are forced to reversely rotate, and the redundant brake fluid in the oil inlet cavity 809 returns to the liquid storage tank 417; if the brake pedal 1 is completely released, the brake is released, at the moment, the pedal stroke measured by the pedal stroke sensor 3 is zero, the brake controller 7 stops the motor 801 according to the pedal stroke, the screw rod 806 moves back to the initial position along with the piston 813 in the reverse direction under the action of the return elastic member 815, the output valve F2 is closed, the input valve F1 is opened, the brake of the brake is released, and redundant brake fluid in the oil inlet cavity 809 returns to the liquid storage tank 417. And in the braking process, the two electromagnetic valves are normally opened so as to maintain the hydraulic balance between the wheel brakes at the two coaxial ends and the corresponding brake pipelines.

2. Brake control method and working process in power-assisted brake mode

When the brake pedal stroke is increased to eliminate the idle stroke S and further increase the brake pedal stroke, the pedal force can be directly transmitted to the piston assembly of the manual cylinder 4 and the manual cylinder 4 has pressure output, and the system works in the power-assisted braking mode. The specific working process is as follows: after the idle stroke S is eliminated, when S is 0, the brake pedal force acts on the piston assembly through the support pin 2, the push rod 401 and the rack 403 and moves forward, so that the first front leather cup 412 and the second front leather cup 419 cover the first compensation hole C1 and the second compensation hole C2 respectively, at this time, the second cavity D1 and the fourth cavity D2 establish high pressure, and the first drain hole E1 and the second drain hole E2 both output pressure, which is transmitted to the oil inlet cavity 809 through the brake pipeline and the oil inlet 808 and acts on the piston 813; in the initial stage of the power-assisted braking, the output valve F2 is in a closed state under the pre-pressure action of the return elastic member 815; the brake controller 7 calculates a target current of the motor 801 according to the pedal stroke signal and a preset power-assisted characteristic curve, drives the motor 801 to work, drives the ball screw pair to apply a thrust force to the screw 806 through the coupler 802, overcomes the pre-pressure of the return elastic member 815 to close the input valve F1 and open the output valve F2; after the input valve F1 is closed, the thrust transmitted to the screw rod 806 by the motor 801 acts on the piston 813 through the input valve F1 in a closed state; at this time, the force acting on the piston 813 includes pedal force transmitted to the oil inlet cavity 809 through the manual cylinder 4 and a brake pipeline, and also includes motor force transmitted to the screw rod 806 through the coupler 802 and the nut 804, the piston 813 moves along the axial direction under the combined action of the pedal force and the motor torque, the volume of the oil outlet cavity 816 is reduced, and the generated pressure is output to a corresponding brake through the brake pipeline, so that the power-assisted brake is realized; when the brake pedal 1 is released in the power-assisted braking mode, the pedal force and the hydraulic pressure acting on the piston 813 are both reduced, the pedal stroke measured by the pedal stroke sensor 3 is reduced, the brake controller 7 accordingly reduces the target current of the motor 801, the torque of the motor 801 and the thrust acting on the lead screw 806 and the piston 813 are also reduced, so that the oil outlet cavity 816 and the brake pressure are reduced, the nut 804, the coupling 802 and the motor 801 are forced to reversely rotate, and the redundant brake fluid in the oil inlet cavity 809 returns to the liquid storage tank 423; if the brake pedal 1 is released sufficiently in the power-assisted braking mode, resulting in an idle stroke S >0 in fig. 3, the system switches from the power-assisted braking mode to the brake-by-wire mode. And in the braking process, the two electromagnetic valves are normally opened so as to maintain the hydraulic balance between the wheel brakes at the two coaxial ends and the corresponding brake pipelines.

3. Brake control method and working process in autonomous brake mode

When the brake controller 7 receives a brake request from other electronic control systems, the system works in an autonomous braking mode. The specific working process in the autonomous braking mode is as follows: the brake controller 7 calculates a target torque of the motor 801 according to the received brake requests from other electric control systems, and then respectively sends torque commands to the motor 801 to control each electric cylinder to work, so that the brake is automatically braked; the control in the brake-by-wire mode depends on the magnitude of the pedal stroke, and the control in the autonomous braking mode depends on the braking request from other electronic control systems, except that the working process in the two modes is the same. And in the braking process, the two electromagnetic valves are normally opened so as to maintain the hydraulic balance between the wheel brakes at the two coaxial ends and the corresponding brake pipelines.

4. Brake control method and working process in failure protection brake mode

When one brake circuit fails, the system operates in a fail-safe braking mode.

When the brake controller 7 detects that one brake circuit of the system fails, failure protection braking can be implemented by applying a target torque larger than that of the motor of the non-failed brake circuit when the system normally works; at this time, the brake controller 7 first calculates a target assist force or a target braking force according to a pedal stroke sensor signal or a braking request from another electronic control system, then distributes it to each wheel brake of the non-failed brake circuit, and then controls the electric cylinder output torque of the non-failed brake circuit, thereby implementing fail-safe braking. In determining the target assistance or target braking force of the respective wheel brake in the fail-safe braking mode, the maximum torque of the respective electric machine should not be exceeded or, according to a specific embodiment and with reference to relevant regulatory requirements, be determined. And in the braking process, the two electromagnetic valves are normally opened so as to maintain the hydraulic balance between the wheel brakes at the two coaxial ends and the corresponding brake pipelines.

The brake release in the fail safe brake mode is the same as the autonomous brake mode and the like.

5. Working process in failure manpower backup braking mode

If the electric control braking function of the braking system is completely lost due to any fault, namely, the four braking circuits cannot generate effective braking action by depending on the work of the motor 801, the manual backup braking can be implemented. In the failed manual backup braking mode, if the driver steps on the brake pedal 1, the pedal force pushes the piston assembly of the manual cylinder 4 through the support pin 2, the push rod 401 and the rack 403, and the braking pressure established by the manual cylinder 4 is transmitted to the oil inlet cavity 809 through the braking pipeline. Because the motor 801 does not work, the output valve F2 of the electric cylinder is closed, and therefore the oil inlet cavity 809 and the oil outlet cavity 816 of the electric cylinder are in a brake fluid isolation state; at this time, the piston 813 is moved by the pressure from the manual cylinder 4 in the oil inlet chamber 809, and the pressure generated in the oil outlet chamber 816 is output to the brake through the brake pipe, thereby applying the manual backup brake. And in the braking process, the two electromagnetic valves are normally opened so as to maintain the hydraulic balance between the wheel brakes at the two coaxial ends and the corresponding brake pipelines.

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

Claims (10)

1. A distributed braking system with functions of manpower failure backup and shaft pressure equalization comprises a brake pedal (1), a manpower cylinder (4), a brake controller (7) and a power supply (6), and is characterized by further comprising at least three electric cylinders electrically connected with the brake controller (7), wherein the electric cylinders are respectively connected with a liquid discharge hole of the manpower cylinder (4) through a brake pipeline, the electric cylinders are correspondingly connected to the same number of wheel brakes on an automobile one by one, and each electric cylinder and one corresponding wheel brake form a brake loop;

the two wheel brakes at two ends of the same shaft are communicated through a brake pipeline, an electromagnetic valve is arranged on the brake pipeline, and the electromagnetic valve is electrically connected with the brake controller (7);

the brake controller (7) is respectively connected with the pedal stroke sensor (3) and the pressure sensor (5) through signal lines and is used for measuring the stroke of the brake pedal (1) and the pressure of the manual cylinder (4).

2. The distributed brake system with human failure backup and axle pressure equalization of claim 1 wherein the wheel brakes comprise a first wheel brake (9), a second wheel brake (10), a third wheel brake (11) and a fourth wheel brake (12); the solenoid valves comprise a first solenoid valve (13a) arranged on a brake line between the first wheel brake (9) and the second wheel brake (10), and a second solenoid valve (13b) arranged on a brake line between the third wheel brake (11) and the fourth wheel brake (12).

3. The distributed brake system with human failure backup and axle pressure equalization of claim 1 wherein said electric cylinders comprise electric cylinder block (817); the electric cylinder body (817) is fixedly connected with the shell (818), a motor (801) is arranged on the shell (818), the motor (801) drives the piston (813) to slide through a pushing device, and the pushing device comprises a pushing rod driven by the motor (801); a through hole is formed in the middle of the piston (813), and the push rod movably penetrates through the through hole and forms an oil liquid channel for oil to pass through with the inner side wall of the through hole; an input valve (F1) and an output valve (F2) which are communicated with the oil liquid channel are respectively arranged on two sides of the push rod which are positioned on the through hole, and a return elastic element (815) is arranged between the end part of the push rod which penetrates through the through hole and the electric cylinder body (817); the electric cylinder body (817) is provided with an oil inlet (808) and an oil outlet (814) on two sides of the piston (813) respectively.

4. The distributed brake system with human failure backup and axle pressure equalization of claim 3 wherein said pushing means is a ball screw pair comprising a nut (804) and a push rod, said push rod being a screw (806); the screw rod (806) is provided with a first conical surface (V1) and a second conical surface (V2) which are respectively arranged on two sides of the through hole and matched with the piston (813) to open and close the oil passage; the first conical surface (V1) cooperates with a third conical surface (V3) arranged on the piston (813) to form the input valve (F1), and the second conical surface (V2) cooperates with a fourth conical surface (V4) arranged on the piston (813) to form the output valve (F2); the first conical surface (V1) tapers towards the piston (813) and the second conical surface (V2) tapers away from the piston (813); when the return elastic member (815) is in a pre-stressed state, the output valve (F2) is closed, and the input valve (F1) is opened.

5. The distributed brake system with the functions of manpower failure backup and shaft pressure equalization as claimed in claim 4, wherein the inside of the housing (818) is a cylindrical hollow structure, the inside of the housing comprises a first cylindrical cavity, a second cylindrical cavity and a third cylindrical cavity, the inner diameters of the first cylindrical cavity, the second cylindrical cavity and the third cylindrical cavity are sequentially increased, a partition surface is arranged between the first cylindrical cavity and the second cylindrical cavity, and a through hole for the screw rod (806) to pass through is formed in the partition surface; a shaft shoulder is formed between the second cylindrical cavity and the third cylindrical cavity, the nut (804) is rotatably arranged in the third cylindrical cavity, and one end of the nut (804) is fixed on the shaft shoulder through a bearing (805); one end of the shell (818) close to the piston (813) extends outwards in the radial direction to form a boss, and the boss is matched with the opening of the electric cylinder body (817) in a sealing mode and fixedly connected with the opening.

6. The distributed brake system with manpower fail-safe and axle pressure equalization function of claim 4 characterized in that the lead screw (806) is provided with an annular bottom surface (V5) between the first conical surface (V1) and the second conical surface (V2), the diameter of the annular bottom surface (V5) is smaller than the inner diameter of the through hole.

7. The distributed brake system with human failure backup and axle pressure equalization of claim 4 wherein said lead screw (806) is provided with a guide slot into which one end of a guide pin (810) fixed in said housing (818) is inserted.

8. The distributed brake system with human failure backup and axle pressure equalization of claim 1 wherein the human operated cylinder (4) comprises:

the brake pedal comprises a liquid storage tank (423), a manual cylinder body communicated with the liquid storage tank (423), a piston assembly arranged in the manual cylinder body in a sliding mode and a rack (403) used for driving the piston assembly to slide, wherein the rack (403) is connected with the brake pedal (1) through a push rod (401), and an idle stroke (S) is formed between the rack (403) and the piston assembly; the manual cylinder (4) further comprises an end cover (404) connected with a cylinder body of the manual cylinder, a gear (405) meshed with the rack (403) is further arranged in the end cover (404), and rotation of the gear (405) around the axis of the gear outputs a rotation angle signal through the pedal stroke sensor (3);

the piston assembly comprises a first front piston (413) and a second front piston (418) which are arranged along the sliding direction of the piston assembly, a first rear piston (409) which is connected with the first front piston (413) and is matched with the rack (403), and a second rear piston (416) which is used for connecting the second front piston (418) and the first rear piston (409), a first cavity (A1) is formed among the first front piston (413), the first rear piston (409) and the inner wall of the manual cylinder body, a second cavity (D1) is formed among the first front piston (413), the second rear piston (416) and the inner wall of the manual cylinder body, a third cavity (A2) is formed among the second rear piston (416), the second front piston (418) and the inner wall of the manual cylinder body, a fourth cavity (D2) is formed between the second front piston (418) and the inner wall of the manual cylinder body;

the manpower jar cylinder body is provided with: a first liquid supply hole (B1) communicated with the liquid storage tank (423) and the first cavity (A1), a first compensation hole (C1) communicated with the liquid storage tank (423) and the second cavity (D1), a second liquid supply hole (B2) communicated with the liquid storage tank (423) and the third cavity (A2), a second compensation hole (C2) communicated with the liquid storage tank (423) and the fourth cavity (D2), a first liquid discharge hole (E1) communicated with the second cavity (D1) and a second liquid discharge hole (E2) communicated with the fourth cavity (D2);

a first front leather cup (412) is arranged on the first front piston (413), a second front leather cup (419) is arranged on the second front piston (418), a first elastic piece (415) is arranged between the first front piston (413) and the second rear piston (416), a second elastic piece (421) is arranged between the second front piston (418) and the inner wall of the manual cylinder body, the first rear piston (409) is in sliding connection with the second rear piston (416), when the first elastic piece (415) is in a prepressing state, the first front leather cup (412) is located between the first liquid supply hole (B1) and the first compensation hole (C1), and when the second elastic piece (421) is in a prepressing state, the second front leather cup (419) is located between the second liquid supply hole (B2) and the second compensation hole (C2); the first elastic member (415) has a larger elastic coefficient than the second elastic member (421).

9. The distributed brake system with the functions of manpower failure backup and shaft pressure equalization as claimed in claim 8, characterized in that an elastic member (406) is arranged between the rack (403) and the inner wall of the manpower cylinder body, one side of the first rear piston (409) facing the rack (403) is provided with an insertion hole (B), and the rack (403) is provided with a top abutting portion (C) which is in insertion fit with the insertion hole (B); when the elastic piece (406) is in a pre-pressing state, the idle stroke (S) exists between the end surface of the abutting part (C) and the bottom surface of the insertion hole (B); the insertion hole (B) is a cylindrical hole, the bottom surface of the cylindrical hole is in a concave spherical surface shape, the abutting part (C) is a cylinder, and the end face is in a convex spherical surface shape.

10. The distributed brake system with human failure backup and axle pressure equalization of claim 2, it is characterized in that the number of the electric cylinders is four, the electric cylinders comprise a first electric cylinder (8a), a second electric cylinder (8b), a third electric cylinder (8c) and a fourth electric cylinder (8d), the first electric cylinder (8a) is communicated with the first wheel brake (9) through a brake pipeline to form a first brake circuit, the second electric cylinder (8b) is communicated with the second wheel brake (10) through a brake pipeline to form a second brake circuit, the third electric cylinder (8c) is communicated with the third wheel brake (11) through a brake pipeline to form a third brake circuit, and the fourth electric cylinder (8d) is communicated with the fourth wheel brake (12) through a brake pipeline to form a fourth brake circuit.

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