CN110053598B

CN110053598B - Pedal comfortable and safe ABS system

Info

Publication number: CN110053598B
Application number: CN201910292090.9A
Authority: CN
Inventors: 汪伟; 马梦琪; 罗金; 姜书杰; 汪永志
Original assignee: Jiangsu University of Technology
Current assignee: Jiangsu University of Technology
Priority date: 2019-04-12
Filing date: 2019-04-12
Publication date: 2020-05-05
Anticipated expiration: 2039-04-12
Also published as: CN110053598A

Abstract

The invention discloses a pedal comfortable and safe ABS system, which comprises: the inner cavity of each master brake pump is divided into a left cavity and a right cavity by a piston, and corresponding piston rods penetrate through the right cavity and the right end wall and extend out of the master brake pumps and are connected together; the bottom of the left end of a left cavity in each master cylinder is connected with an output branch pipe, a compression spring is arranged in the left cavity, and the output branch pipes corresponding to the master cylinders are connected with each other to form a total output pipe; the middle position of the bottom of each brake master pump is connected with a balance branch pipe, the balance branch pipes are connected with the output pipe or any output branch pipe through a communication branch pipe after being mutually connected, and the communication branch pipe is provided with a normally closed electromagnetic valve C; and the brake fluid storage tank is arranged at the upper part of the master cylinder and is respectively communicated with the inner cavity of each master cylinder through a communicating main pipe. In the working process, the response speed of pressure change in a brake pipeline after a driver suddenly releases a brake pedal is improved, and meanwhile the problem that the brake pedal shakes repeatedly in the working process of an ABS system is solved.

Description

Pedal comfortable and safe ABS system

Technical Field

The invention relates to the technical field of braking, in particular to an ABS system.

Background

As a standard active safety device for automobiles, ABS (Anti-lock Braking System) plays an important role in driving safety. However, pressure fluctuation in the brake pipeline during operation acts on the brake pedal through the brake master cylinder, the piston and the piston rod, so that the brake pedal is repeatedly shaken. Although the phenomenon does not affect the driving safety of the driver, the comfort level of the driver is greatly affected, and the technical problem to be solved is urgently needed.

Some solutions to this technical problem have appeared in the prior art. For example, chinese patent CN201610405557 discloses an electrohydraulic composite brake system for improving pedal feel during ABS braking, which achieves the objective by isolating a brake master cylinder (i.e. a master cylinder) from the rest of the brake system by a master cylinder isolation valve during ABS operation, and although the phenomenon of "repeated shaking" is solved to some extent, if a driver suddenly loosens or releases a brake pedal, a signal is transmitted to an electronic control unit after a pressure sensor of the master cylinder detects rapid attenuation of pressure, and the electronic control unit makes a judgment to release the ABS operation state and reset each solenoid valve in a brake pipeline to an initial state, so that hydraulic pressure of a brake cylinder is reduced, and the objective of reducing wheel braking force is achieved. The process is obviously delayed for a long time, and the pressure decay change in the brake pipeline is slow to respond. In addition, in the technical scheme that the electronic control unit controls various components such as the main cylinder isolation electromagnetic valve to isolate the brake main cylinder and prevent the pedal from shaking repeatedly, the system has a plurality of components, complex system control process and poor reliability.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides the ABS system with comfortable and safe pedal, which effectively solves the problem of repeated shaking of the brake pedal in the prior art.

In order to achieve the purpose, the invention is realized by the following technical scheme:

a pedal comfort safety ABS system comprising:

the inner cavity of each master cylinder is divided into a left cavity and a right cavity by a piston, piston rods correspondingly arranged on the pistons penetrate through the right cavity and the right end wall to extend out of the master cylinders, and the piston rods corresponding to the master cylinders are connected together and are in transmission connection with a pedal provided with a brake switch; the bottom of the left end of a left cavity in each master cylinder is connected with an output branch pipe, a compression spring for connecting the inner wall of the left end with an adjacent piston is arranged in the left cavity, and the output branch pipes corresponding to the master cylinders are connected with each other to form a total output pipe; the middle position of the bottom of each master cylinder is connected with a balance branch pipe, the balance branch pipes corresponding to the master cylinders are mutually connected and are connected with the output pipe or any output branch pipe through a communicating branch pipe, and the communicating branch pipe is provided with a normally closed electromagnetic valve C;

set up in the brake fluid liquid storage pot on master cylinder upper portion, communicate with the inner chamber of each master cylinder respectively through a communicating main, should communicate in the house steward including: two communicating pipes connected with each brake master pump and the communicating pipes are connected together to form a communicating pipe which is connected with a brake fluid storage tank and is provided with a normally open electromagnetic valve A; in two communicating pipes connected with each master cylinder, a first communicating pipe is connected to the middle part of the master cylinder, and a second communicating pipe is connected to the right end of the master cylinder; the normally open electromagnetic valve A and the normally closed electromagnetic valve C are connected in parallel, the obtained parallel branch is connected in series with a parallel branch formed by connecting the controlled ends of the relay K1, the relay K2 and the relay K3 in parallel, and the parallel branch is connected in series with a power supply to form a control loop; the joint of each balance branch pipe and the corresponding master brake pump is positioned on the right side of the joint of the first communication pipe and the master brake pump and is close to the first communication pipe;

the ABS normally open valve and the ABS normally closed valve are sequentially arranged on a braking branch of an output pipe of the master brake pump, the ABS normally open valve and the control end of the relay K1 are connected in series in the same circuit, and the ABS normally closed valve and the control end of the relay K2 are connected in series in the same circuit;

the brake cylinder is arranged on a brake pipeline between the ABS normally-open valve and the ABS normally-closed valve;

the brake system comprises a pressure valve, a hydraulic pump, a suction valve, a low-pressure energy accumulator, a relay K3 and a relay K3, wherein the pressure valve, the hydraulic pump and the suction valve are sequentially arranged on the other brake branch of an output pipe of the master brake pump, and the low-pressure energy accumulator is arranged on a brake branch between an ABS normally-closed valve and the suction valve; and

the ABS control unit is respectively electrically connected with the ABS normally-open valve, the ABS normally-closed valve, the hydraulic pump and the brake switch on the pedal and is used for judging whether the vehicle enters a braking state or not according to the signal of the brake switch and identifying whether the vehicle has a locking tendency or not according to the signal detected by the vehicle wheel rotating speed sensor; when the locking tendency occurs, the control information is sent to control the ABS normally-open valve, the ABS normally-closed valve and the hydraulic pump to act, so that the on-off of the controlled end circuit of the relay K1, the relay K2 and the relay K3 is controlled, the normally-open electromagnetic valve A and the normally-closed electromagnetic valve C are controlled to act, and the wheels are prevented from being locked.

The invention provides a pedal comfortable and safe ABS system with a more simplified structure and higher reliability, which improves the response speed of pressure change in a brake pipeline after a driver suddenly releases a brake pedal in the working process, enables the braking force of wheels to change along with the displacement of the brake pedal more quickly, and solves the problem of repeated shaking of the brake pedal in the working process of the ABS system. In addition, a plurality of brake master pumps are arranged in the ABS system, when one brake master pump is damaged and loses brake force, other brake master pumps can still generate brake force, so that the driving safety is ensured, in addition, only one normally open electromagnetic valve A and one normally closed electromagnetic valve C are adopted in the whole system, the usage amount of the electromagnetic valves is simplified, the cost is greatly reduced, the fault points of the system are reduced, and the reliability is improved.

Drawings

A more complete understanding of the present invention, and the attendant advantages and features thereof, will be more readily understood by reference to the following detailed description when considered in conjunction with the accompanying drawings wherein:

FIG. 1 is a schematic overall structure diagram of a pedal comfort safety type ABS system;

FIG. 2 is a schematic structural diagram of one embodiment of a master cylinder;

FIG. 3 is a schematic diagram of a solenoid valve control loop

Fig. 4 is a schematic structural diagram of another embodiment of the master cylinder.

Reference numerals:

1-ABS normally open valve, 2-ABS normally closed valve, 3-brake cylinder, 4-pressure valve, 5-hydraulic pump, 6-suction valve, 7-low pressure accumulator, 10/20-brake master pump, 11/21-left chamber, 12/22-right chamber, 13/23-piston, 14/24-piston rod, 15/25-output branch pipe, 16/26-spring, 17-output pipe, 18/28-balance branch pipe, 19-communicating pipe, 27-communicating branch pipe, 33/34/37-sealing ring, 35/36-annular limiting boss, 30-pedal, 31-first communicating pipe, 32-second communicating pipe, 40-brake fluid storage tank, Y-power supply, a-normally open electromagnetic valve A, B-normally open electromagnetic valve, C-normally closed electromagnetic valve C, K1-relay K1, K2-relay K2, K3-relay K3.

Detailed Description

In order to make the contents of the present invention more comprehensible, the present invention is further described below with reference to the accompanying drawings. The invention is of course not limited to this particular embodiment, and general alternatives known to those skilled in the art are also covered by the scope of the invention.

In the existing ABS system, an electronic control unit measures pressure change in a master cylinder through a pressure sensor, so that the ABS system exits a working stage and enters a monitoring stage, an ABS normally open valve is opened, a master cylinder isolation valve is opened at the same time, the master cylinder is communicated with the rest part of the ABS system, pressure in a brake cylinder and a brake pipeline is reduced along with the pressure of the master cylinder, and braking force of wheels is relieved. The response speed for releasing the wheel braking force is slower because the steps of opening the master cylinder isolation valve and enabling the master cylinder to be communicated with the rest part of the ABS system again are added; and because the pressure sensor is needed to judge whether the ABS system needs to quit the working stage or not, and the electronic control unit is needed to control the work of the main cylinder isolation valve, the structure of the system is more complex, the control process is more complex, and the reliability is lower. In addition, when the ABS system enters a boosting stage again from a pressure reduction stage, because the pressure in the brake cylinder is reduced and the pressures in brake pipelines at two sides of an ABS normally open valve are different, the hydraulic pressure in the brake master cylinder is reduced at the moment when the ABS normally open valve is opened, and a driver feels that the brake pedal is retracted; when the hydraulic pump is started, the pressure in a brake pipeline between the hydraulic pump and the brake sub-pump is increased, so that the hydraulic pressure in the brake master pump is increased, and a driver feels that the brake pedal rebounds, so that the brake pedal shakes. In the working process of the ABS system, the ABS system continuously circulates in three working stages of pressurization, pressure maintaining and depressurization, so that the brake pedal can shake repeatedly.

Based on the technical problems in the existing ABS system, the invention provides a brand-new pedal comfortable and safe ABS system, which comprises a plurality of brake master pumps connected in series, for the sake of clearer description, the condition that the ABS system comprises 2 brake master pumps is explained below, and the condition that the ABS system comprises more than 2 brake master pumps is analogized in the same way.

Fig. 1-3 are schematic diagrams of an embodiment of the ABS system, where fig. 1 is a schematic diagram of an overall structure of a pedal comfort safety ABS system, fig. 2 is a schematic diagram of a serial structure of two master cylinders, and fig. 3 is a schematic diagram of a control circuit of an electromagnetic valve. The pedal comfortable and safe ABS system comprises a master cylinder 10 and a master cylinder 20, specifically, the inner cavities of the two master cylinders are respectively divided into a left cavity and a right cavity by a piston (the inner cavity of the master cylinder 10 is divided into a left cavity 11 and a right cavity 12 by a piston 13, the inner cavity of the master cylinder 20 is divided into a left cavity 21 and a right cavity 22 by a piston 23), piston rods correspondingly arranged on the pistons penetrate through the right cavity and the right end wall to extend out of the master cylinder (the piston 13 corresponds to a piston rod 14, the piston 23 corresponds to a piston rod 24, and the piston rod 14 in the master cylinder 10 is connected with the piston rod 24 through the piston 23 in the master cylinder 20, so that the two master cylinders are connected in series; piston rods corresponding to the two master cylinders are connected together and are in transmission connection with a pedal 30 provided with a brake switch, and a sealing ring is arranged at the contact position of the end wall of each master cylinder and the piston rod, so that the sealing performance in the cavity is ensured (the contact position of the master cylinder 10 and the piston rod 14 is provided with a sealing ring 33, the contact position of the master cylinder 20 and the piston rod 24 is provided with a sealing ring 34, and the contact position of the master cylinder 20 and the piston rod 14 is provided with a sealing ring 37); the bottoms of the left ends of the left cavities in the two master cylinders are connected with output branch pipes, compression springs (the master cylinder 10 corresponds to the output branch pipes 15 and the compression springs 16; the master cylinder 20 corresponds to the output branch pipes 25 and the compression springs 26) for connecting the inner walls of the left ends with adjacent pistons are arranged in the left cavities, and the output branch pipes corresponding to the two master cylinders are connected with each other to form a total output pipe 17; the middle positions of the bottoms of the two master cylinders are connected with a balance branch pipe (the master cylinder 10 corresponds to the balance branch pipe 18, the master cylinder 20 corresponds to the balance branch pipe 28), the balance branch pipes corresponding to the two master cylinders are connected with each other and connected with the output pipe 17 or any output branch pipe through a communicating branch pipe 27 (connected with the output branch pipe 15 through the communicating branch pipe 27 in fig. 2), and the communicating branch pipe 27 is provided with a normally closed electromagnetic valve C.

Still including setting up in the brake fluid storage tank 40 on master cylinder upper portion among the ABS system, it communicates with the inner chamber of two master cylinders respectively through a intercommunication house steward, and this intercommunication house steward includes: two communicating pipes connected with each brake master pump and a communicating pipe 19 which is formed by connecting the two communicating pipes together, is connected with a brake fluid storage tank and is provided with a normally open electromagnetic valve A; of the two communication pipes connected to each master cylinder, a first communication pipe is connected to a middle portion of the master cylinder, and a second communication pipe is connected to a right end of the master cylinder (e.g., in the master cylinder 10, the first communication pipe 31 is connected to a middle portion of the master cylinder 10, and the second communication pipe 32 is connected to a right end of the master cylinder 10). As shown in fig. 3, the normally open solenoid valve a and the normally closed solenoid valve C are connected in parallel with each other, and the obtained parallel branch is connected in series with a parallel branch formed by connecting the controlled ends of the relay K1, the relay K2, and the relay K3 in parallel with each other, and is connected in series with the power supply Y to form a control circuit. The joint of each balance branch pipe and the corresponding master cylinder is positioned on the right side of the joint of the first communication pipe and the master cylinder and close to the first communication pipe.

As shown in fig. 1, the ABS system further includes: the ABS normally-open valve 1 and the ABS normally-closed valve 2 are sequentially arranged on a braking branch of an output pipe of the master brake pump, the ABS normally-open valve 1 and the control end of the relay K1 are connected in series in the same circuit, and the ABS normally-closed valve 2 and the control end of the relay K2 are connected in series in the same circuit; the brake cylinder 3 is arranged on a brake pipeline between the ABS normally-open valve and the ABS normally-closed valve; the brake system comprises a pressure valve 4, a hydraulic pump 5 and a suction valve 6 which are sequentially arranged on the other brake branch of an output pipe of a master cylinder, and a low-pressure energy accumulator 7 arranged on a brake branch between an ABS normally-closed valve 1 and the suction valve 6 (when an ABS system is in a decompression stage, the low-pressure energy accumulator 7 can contain all brake fluid in a brake sub-pump 3, so that the problem of insufficient capacity is avoided or the phenomenon of overhigh pressure caused by the fact that the brake fluid is stored in the low-pressure energy accumulator 7 is avoided, the hydraulic pump 5 is not needed to return part of the brake fluid in the low-pressure energy accumulator 7 to the master cylinder 1 to vacate the capacity in the low-pressure energy accumulator 7, the pressure in the low-pressure energy accumulator 7 is reduced), two brake branches on the output pipe side of the master cylinder form a brake circuit in a closed loop, and the hydraulic pump 6 and; and the suction valve 6 and the pressure valve 4 are one-way opening valves for preventing the liquid from flowing backwards. The ABS system also comprises an ABS control unit which is respectively electrically connected with the ABS normally-open valve 1, the ABS normally-closed valve 2, the hydraulic pump 6 and the brake switches on the pedal 30, and is used for judging whether the ABS system enters a braking state or not according to signals of the brake switches and identifying whether wheels have a locking tendency or not according to signals detected by the wheel speed sensors; when a locking tendency occurs, the control information is sent to control the ABS normally-open valve 1, the ABS normally-closed valve 2 and the hydraulic pump 6 to act, so that the on-off of the controlled end circuit of the relay K1, the relay K2 and the relay K3 is controlled, the normally-open electromagnetic valve A and the normally-closed electromagnetic valve C are controlled to act, and the wheels are prevented from being locked.

Based on this, after the ABS system is started in the working process, the ABS system enters the monitoring stage, when the driver steps on the pedal 30, the brake switch is turned on to light the brake light at the tail of the vehicle, and the ABS control unit connected to the brake switch receives the switch signal of the brake switch, and determines that the driver steps on the brake pedal 30 according to the switch signal, that is, determines that the vehicle enters the braking state. In addition, in the monitoring stage, a driver controls the master brake pump 1 to establish brake fluid pressure in the brake branch through the pedal 30, at the moment, the ABS normally-open valve 1 is in an open state, the ABS normally-closed valve 2 is in a closed state, the brake fluid pressure enters the brake slave pumps 3 at the wheels, and the wheel speed is rapidly reduced until the ABS control unit recognizes that the wheels tend to be locked through signals obtained by the wheel speed sensors. At this stage, both master cylinders in the system are in a normal braking state, and for each master cylinder, the piston moves to the left, liquid in the brake fluid storage tank enters the right cavity of the master cylinder from the second communicating pipe, when the piston moves to the left side of the first communicating pipe, braking pressure is generated in the left cavity, the braking pressure gradually increases along with the increase of the moving distance, and braking force is generated in the brake cylinder 3. In addition, since the ABS normally open valve 1, the ABS normally closed valve 2, and the hydraulic pump 5 in the ABS system are all not operated, as shown in fig. 3, the relay K1, the relay K2, and the relay K3 are all not operated, and the controlled end is in the off state, the normally open electromagnetic valve a and the normally closed electromagnetic valve C are not energized and do not operate, that is, the normally open electromagnetic valve a is in the open state, and the normally closed electromagnetic valve C is in the closed state.

When the ABS control unit recognizes that the wheels tend to lock through signals obtained by the wheel speed sensors, the ABS system enters a pressure maintaining stage, the ABS control unit supplies power to the ABS normally-open valve 1 to close the ABS normally-open valve, at the moment, the ABS normally-closed valve 2 still keeps a closed state, and the hydraulic pressure in the brake cylinder 3 keeps unchanged. In the pressure maintaining stage, if the ABS control unit judges that the wheel locking tendency is further increased according to the wheel rotation speed, the pressure reducing stage is started, the ABS control unit continuously supplies power to the ABS normally-open valve 1 to keep the closed state of the ABS normally-open valve 1 and supplies power to the ABS normally-closed valve 2 to open the ABS normally-open valve, at the moment, part of brake fluid in the brake cylinder 3 enters the low-pressure accumulator 7 through the brake branch, the brake pressure in the brake cylinder 3 is reduced, the wheel locking degree is reduced, and the wheel rotation speed is increased. In order to achieve the best braking effect, when the rotating speed of the wheel is increased to a set value, the wheel enters a boosting stage, the ABS control unit cuts off the power of the ABS normally-open valve 1 to open the ABS normally-open valve and cuts off the power of the ABS normally-open valve 2 to close the ABS normally-open valve, meanwhile, the hydraulic pump 5 is started to pump the brake fluid in the low-pressure accumulator 7 to a brake branch close to one side of the ABS normally-open valve 1, the brake fluid pressure in the brake branch is increased, the hydraulic pressure in the brake branch is synchronously increased, and the wheel is braked and decelerated again. When the wheel is locked again, the pressure maintaining stage, the pressure reducing stage and the pressure increasing stage are carried out again, and the steps are repeated in a circulating mode until the ABS system quits the working stage and returns to the monitoring stage due to the fact that the vehicle speed is reduced to the set value or the brake pedal is released. The pressure maintaining stage, the pressure reducing stage and the pressure increasing stage are called working stages.

It can be seen from the above process that, when the ABS system is in the monitoring phase, the ABS system only monitors and does not actually operate, and when the ABS system is in the working phase, the ABS system sequentially circulates among the pressure maintaining phase, the pressure reducing phase, and the pressure increasing phase, and in this process, the ABS normally open valve 1, the ABS normally closed valve 2, or the hydraulic pump 5 is in the controlled working state, so that it is possible to know whether the ABS system is in the working phase by determining whether the ABS normally open valve 1, the ABS normally closed valve 2, or the hydraulic pump 5 is working. When the ABS normally-open valve 1, the ABS normally-closed valve 2 or the hydraulic pump 5 works, current passes through a control circuit connected with the ABS normally-open valve 2 or the hydraulic pump 5, and the current is utilized to control the required electromagnetic valve to work, so that the aim of the invention can be achieved.

Specifically, in the process of cyclic reciprocation of the pressure maintaining stage, the pressure reducing stage and the pressure increasing stage, the ABS normally open valve 1, the ABS normally closed valve 2 and the hydraulic pump 5 in the ABS system are respectively in a working state or simultaneously in a working state, according to the schematic diagram of the electromagnetic valve control loop shown in fig. 3, when the ABS system is in any working state, one of the relays is triggered to communicate the controlled end contact of the corresponding relay, so that the normally open electromagnetic valve a and the normally closed electromagnetic valve C are in a working state, that is, the normally open electromagnetic valve a is closed, the normally closed electromagnetic valve C is opened (the pressure maintaining stage, the ABS control unit supplies power to the ABS normally open valve 1, the controlled end contact of the relay K1 is connected, the normally open electromagnetic valve a and the normally closed electromagnetic valve C are both energized and are in a working state, the pressure reducing stage, the ABS control unit simultaneously supplies power to the ABS normally open valve 1 and the, the normally open electromagnetic valve A and the normally closed electromagnetic valve C are electrified and are in a working state; in the pressurizing stage, the ABS control unit supplies power to the hydraulic pump, the controlled end contact of the relay K3 is switched on, and the normally open electromagnetic valve A and the normally closed electromagnetic valve C are both electrified and are in a working state). By this procedure, the driver steps on the pedal 30 and puts it in braking condition, in a single master cylinder: the piston is located the left side of first connecting pipe, and the piston is located the left side of balance branch pipe and brake master cylinder junction promptly, and left chamber and right chamber pass through balance branch pipe/intercommunication branch pipe intercommunication (the left chamber between two brake master pumps passes through output branch pipe intercommunication, the right chamber passes through balance branch pipe intercommunication, and left chamber and right chamber pass through the intercommunication branch pipe intercommunication), make the hydraulic pressure force between left chamber and the right chamber balanced each other, and the effort that comes from on the piston at this moment is become only spring force by the hydraulic pressure force in the left chamber with spring force. That is, when the ABS system is just in operation, the force applied to the piston from the left side is reduced at the moment when the normally closed solenoid valve C is opened, and the driver feels the pedal retraction, and the pedal 30 stops the retraction as the amount of compression of the spring is increased until the elastic force is balanced with the pedal force of the driver. Then when the ABS system is in 3 working phase cycle changes, the pressure change in the brake branch is respectively transmitted to the left cavity and the right cavity of each master cylinder, and the hydraulic pressure at the two sides can be mutually offset, so that the fluctuating pressure can not be generated to the pedal 30, and a driver can not naturally feel the repeated shaking of the pedal 30.

Thereafter, when the driver suddenly releases the brake pedal 30, in a single master cylinder: the piston will move right rapidly under the spring force and the pedal 30 will follow. Before the pedal 30 is reset, the brake lamp switch is still in a closed state, at the moment, the ABS system is still in a working state, namely a normally open electromagnetic valve A is still in a closed state, and a normally closed electromagnetic valve C is still in an open state; when the piston moves to the right side of the joint of the corresponding balance branch pipe and the master cylinder, the left cavity is increased in volume and rapidly reduced in pressure, brake fluid in the brake branch pipe is sucked into the left cavity of the master cylinder (in the process that the piston moves from the joint of the balance branch pipe and the master cylinder to the limit position of the right side of the master cylinder, the volume of the left cavity of the master cylinder is enough to accommodate the whole brake branch pipe, the low-pressure accumulator 7 and the residual brake fluid in the brake branch pump 3), and the pressure in the brake branch pipe is rapidly reduced to 0. When the ABS system detects that the pedal is reset and recovers to the monitoring stage, the ABS normally open valve 1 is opened, the pressure in the brake cylinder 3 and the brake branch is rapidly synchronized and reduced to 0, and the braking force on the wheels is released.

In another embodiment, as shown in fig. 4, an annular limiting boss (the master cylinder 10 corresponds to the annular limiting boss 35, and the master cylinder 20 corresponds to the annular limiting boss 36) for limiting the piston to move to the right limit position of the master cylinder is respectively arranged in the right cavities of the two master cylinders, and when the piston moves to the annular limiting boss, the pedal is in the reset state. A brake fluid storage tank 3 is arranged at the upper part of the master cylinder and is communicated with the inner cavity of the master cylinder through two communicating pipes, wherein a first communicating pipe is arranged at the middle part of the master cylinder, and a second communicating pipe is communicated with the inner cavity of the master cylinder at the right side of the annular limiting boss; the joint of the balance branch pipe and the master cylinder is positioned between the joint of the first communication pipe and the master cylinder and the annular limiting boss and close to one side of the first communication pipe.

After the ABS system is started in the working process, the ABS system enters a monitoring stage, when a driver steps on a pedal 30, two master brake pumps in the system are in a conventional braking state, a piston moves to the left for each master brake pump, liquid in a brake liquid storage tank enters a right cavity of the master brake pump through the right side of an annular limiting boss of a second communicating pipe, when the piston moves to the left side of a first communicating pipe, brake pressure is generated in the left cavity, the brake pressure gradually increases along with the increase of the moving distance, and braking force is generated in a brake sub-pump 3.

Thereafter, when the driver suddenly releases the brake pedal 30, in a single master cylinder: the piston will move right rapidly under the spring force and the pedal 30 will follow. Before the pedal 30 is reset, the brake lamp switch is still in a closed state, at the moment, the ABS system is still in a working state, namely a normally open electromagnetic valve A is still in a closed state, and a normally closed electromagnetic valve C is still in an open state; when the piston moves to the right side of the joint of the balance branch pipe and the master cylinder, the volume of the left cavity is continuously increased, the pressure is rapidly reduced, the brake fluid in the brake branch pipe is sucked into the left cavity of the master cylinder (in the process that the piston moves from the joint of the balance branch pipe and the master cylinder to the annular limiting boss, the volume of the left cavity of the master cylinder is enough to accommodate the rest brake fluid in the whole brake branch pipe, the low-pressure accumulator 7 and the brake branch pump 3), and the pressure in the brake branch pipe is rapidly reduced to 0. When the ABS system detects that the pedal is reset and recovers to the monitoring stage, the ABS normally open valve 1 is opened, the pressure in the brake cylinder 3 and the brake branch is rapidly synchronized and reduced to 0, and the braking force on the wheels is released.

Claims

1. A pedal comfort safety type ABS system, comprising:

set up in the brake fluid liquid storage pot on master cylinder upper portion, communicate with the inner chamber of each master cylinder respectively through a communicating main, should communicate in the house steward including: two communicating pipes connected with each brake master pump and the communicating pipes are connected together to form a communicating pipe which is connected with a brake fluid storage tank and is provided with a normally open electromagnetic valve A; in two communicating pipes connected with each master cylinder, a first communicating pipe is connected to the middle part of the master cylinder, and a second communicating pipe is connected to the right end of the master cylinder; in the control circuit, a normally open electromagnetic valve A and a normally closed electromagnetic valve C are connected in parallel, and the obtained parallel branch is connected in series with a parallel branch formed by connecting the controlled ends of a relay K1, a relay K2 and a relay K3 in parallel, and is connected in series with a power supply to form a control loop; the joint of each balance branch pipe and the corresponding master brake pump is positioned on the right side of the joint of the first communication pipe and the master brake pump and is close to the first communication pipe;

the ABS control unit is respectively electrically connected with the ABS normally-open valve, the ABS normally-closed valve, the hydraulic pump and the brake switch on the pedal and is used for judging whether the vehicle enters a braking state or not according to the signal of the brake switch and identifying whether the vehicle has a locking tendency or not according to the signal detected by the vehicle wheel rotating speed sensor; when the locking tendency occurs, the control information is sent to control the ABS normally-open valve, the ABS normally-closed valve and the hydraulic pump to act, so that the on-off of the controlled end circuit of the relay K1, the relay K2 and the relay K3 is controlled, the normally-open electromagnetic valve A, the normally-closed electromagnetic valve C and the hydraulic pump are controlled to act, and the wheels are prevented from being locked.

2. The ABS system of claim 1 wherein each master cylinder has an annular stop boss in its right chamber for limiting the movement of the piston to a limit position at the right side of the master cylinder, the pedal being in a reset position when the piston moves to said annular stop boss.

3. The ABS system of claim 2 wherein in two communicating pipes connected to each master cylinder, a first communicating pipe is connected to the middle of the master cylinder, and a second communicating pipe is connected to the inner chamber of the master cylinder at the right side of the annular limiting boss; the joint of the balance branch pipe and the master cylinder is positioned between the joint of the first communication pipe and the master cylinder and the annular limiting boss and close to one side of the first communication pipe.