CN106696938B - Decoupling type electric power-assisted braking system based on X-shaped arrangement - Google Patents
Decoupling type electric power-assisted braking system based on X-shaped arrangement Download PDFInfo
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- CN106696938B CN106696938B CN201611161795.XA CN201611161795A CN106696938B CN 106696938 B CN106696938 B CN 106696938B CN 201611161795 A CN201611161795 A CN 201611161795A CN 106696938 B CN106696938 B CN 106696938B
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
- B60T13/00—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems
- B60T13/74—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with electrical assistance or drive
- B60T13/745—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with electrical assistance or drive acting on a hydraulic system, e.g. a master cylinder
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
- B60T2270/00—Further aspects of brake control systems not otherwise provided for
- B60T2270/60—Regenerative braking
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Abstract
The invention discloses a decoupling type electric power-assisted braking system based on X-shaped arrangement, which comprises a brake pedal, an electric power-assisted conversion mechanism, a brake master cylinder, a liquid storage tank, an electric liquid storage tank, a hydraulic system and a brake wheel cylinder, wherein a push rod of the brake pedal is connected with the input end of the electric power-assisted conversion mechanism, the output end of the electric power-assisted conversion mechanism is connected with a piston push rod of the brake master cylinder, the liquid storage tank is connected to the brake master cylinder, and a connecting port in the hydraulic system is respectively connected with the brake master cylinder, the electric liquid storage tank and the brake wheel cylinder. Has the advantages that: the motor is adopted for assisting braking, the vacuum is not depended on, and the pedal feeling similar to that of a vacuum booster can be kept; during regenerative braking, the pedal feeling can be kept unchanged by adjusting the power-assisted characteristic of the motor; the brake fluid displacement amount of the brake master cylinder is equal to the brake fluid inlet amount of the liquid storage cylinder by controlling the motor of the liquid storage cylinder, so that the control is more accurate; the cooperative braking of regenerative braking and friction braking is realized, and the braking energy can be recovered as much as possible.
Description
Technical Field
The invention relates to an electric power-assisted brake system, in particular to a decoupling type electric power-assisted brake system based on X-shaped arrangement.
Background
At present, the hydraulic braking system of most cars adopts vacuum helping hand, then need dispose the vacuum pump alone in order to extract the vacuum in using new energy automobile, and this scheme increases the cost, is unfavorable for spatial arrangement. In addition, a part of automobiles adopt motor-assisted braking, the assistance is controllable, a vacuum pump is not needed, and the arrangement space is saved.
The regenerative braking of the automobile can realize the recovery of the braking energy of the automobile and increase the utilization rate of the total energy of the automobile. The regenerative braking refers to that when the new energy automobile decelerates or brakes, the motor is used for reversely dragging to generate braking torque to act on a driving shaft, and partial mechanical energy of the automobile is converted into electric energy to be stored in an energy storage element. In the process, the regenerative braking force replaces part of the friction braking force of the driving shaft, so that the friction braking force of the driving shaft can be correspondingly reduced, and the total braking force and the braking force distribution of the front shaft and the rear shaft can meet the requirements of braking regulations.
The regenerative braking force replaces part of the driving shaft friction braking force, so that the brake fluid for generating the part of the friction braking force needs to be separately stored, and the brake pedal and the brake wheel cylinder are decoupled. For the automobile adopting the vacuum booster, the boosting characteristic of the vacuum booster is fixed, and the pedal feel simulator with the PV characteristic meeting the pedal feel requirement needs to be designed to keep the pedal feel unchanged and complicated when the pedal is decoupled. The electric power-assisted braking system can meet different pedal feel requirements by adjusting the power-assisted size of the motor, only one liquid storage cylinder with variable volume needs to be added during decoupling, and redundant brake fluid is led into the liquid storage cylinder during regenerative braking, so that the decoupling of the pedal and the wheel cylinder can be realized.
Disclosure of Invention
The invention aims to solve the problems and provides a decoupling type electric power-assisted brake system based on an X-type arrangement.
The invention provides a decoupling type electric power-assisted brake system based on X-type arrangement, which comprises a brake pedal, an electric power-assisted conversion mechanism, a brake master cylinder, a liquid storage tank, an electric liquid storage tank, a hydraulic system and a brake wheel cylinder, wherein a push rod of the brake pedal is connected with an input end of the electric power-assisted conversion mechanism, an output end of the electric power-assisted conversion mechanism is connected with a piston push rod of the brake master cylinder, the liquid storage tank is connected onto the brake master cylinder, and a connecting port in the hydraulic system is respectively connected with the brake master cylinder, the electric liquid storage tank and the brake wheel cylinder.
The electric power-assisted conversion mechanism comprises a power-assisted motor, a primary gear, a secondary gear, a push rod, a ball screw, a screw nut and a liquid storage cylinder, wherein the primary gear is arranged on an output shaft of the power-assisted motor and is externally meshed with the secondary gear, the secondary gear is fixed on the screw nut through a key, the screw nut is driven by the secondary gear to rotate so as to drive the ball screw to do linear motion, the ball screw is internally hollow, the right side of the ball screw is provided with a bottom, the bottom is provided with holes and is in one-to-one correspondence with the holes on the bottom surface of the right side of the push rod, the push rod is fixed on the bottom surface of the right side inside the screw nut through bolts, so that the push rod can be driven to do linear motion when the ball screw moves, the bottom of the right side of the push rod is provided with threaded holes, the push rod can be fixed on the bottom of the right side of the ball screw through the bolts and the threaded holes, the left side of the push rod is connected with a piston in the liquid storage cylinder, and the piston in the liquid storage cylinder can be driven to do linear motion.
The hydraulic system comprises a first hydraulic system and a second hydraulic system, the first hydraulic system and the second hydraulic system are of a symmetrical structure, the first hydraulic system and the second hydraulic system respectively comprise an isolation valve, a suction valve, a plunger pump, a stop valve, a reversing valve, a liquid return valve, a first booster valve, a second booster valve, a first pressure reducing valve and a second pressure reducing valve, wherein the isolation valve is a normally open type opening and closing valve, one end of the isolation valve is connected with a brake main cylinder, one end of the isolation valve is connected with an A port of the reversing valve and the stop valve, the two ends of the isolation valve are provided with a first one-way valve, the outlet end of the first one-way valve is connected with the brake main cylinder, the outlet end of the plunger pump is connected with the isolation valve through a pipeline, a damper and a second one-way valve are arranged on a connecting pipeline, the outlet end of the second one-way valve is arranged on one side of the damper, the inlet end of the plunger pump is also connected with the first pressure reducing valve and the second pressure reducing valve through a pipeline, an energy accumulator and a third one-way valve are arranged on the connecting pipeline, the outlet end of a third one-way valve is arranged on one side of the inlet of the plunger pump, an energy accumulator is connected between the inlet end of the third one-way valve and the first pressure reducing valve and the second pressure reducing valve, the inlet end of the plunger pump is also connected with a suction valve, the other end of the suction valve is connected with a brake master cylinder, the plunger pumps in the first hydraulic system and the second hydraulic system are driven by a common plunger pump motor, a reversing valve is a two-position three-way valve, wherein an A port is connected with an isolation valve, a B port is connected with a first pressure increasing valve, a C port is connected with a liquid return valve and an electric liquid storage cylinder, the A port and the C port are communicated to be in a left position, the A port and the B port are communicated to be in a right position and are in a normal state, the other end of the liquid return valve is also connected with the first pressure increasing valve, the electric liquid storage cylinder is arranged on a pipeline connecting the two liquid return valves and the two reversing valves in the first hydraulic system and the second hydraulic system, and the two ends of the first pressure increasing valve are provided with fourth one-way valves, the outlet end of the fourth one-way valve is arranged on one side of the reversing valve, the stop valve is a normally-open type opening and closing valve, one end of the stop valve is connected to the outlet of the isolating valve, the other end of the stop valve is connected to the inlet of the second booster valve, fifth one-way valves are arranged at two ends of the second booster valve, and the outlet ends of the fifth one-way valves are arranged on one sides of the stop valves.
The first pressure increasing valve and the second pressure increasing valve are high-speed switch valves and are normally open valves, and the first pressure reducing valve and the second pressure reducing valve are high-speed switch valves and are normally closed valves.
The brake wheel cylinder comprises a left front wheel cylinder, a right rear wheel cylinder, a left rear wheel cylinder and a right front wheel cylinder, wherein the left front wheel cylinder is respectively connected with a first pressure increasing valve and a first pressure reducing valve in a first hydraulic system, the right rear wheel cylinder is respectively connected with a second pressure increasing valve and a second pressure reducing valve in the first hydraulic system, the left rear wheel cylinder is respectively connected with a second pressure increasing valve and a second pressure reducing valve in a second hydraulic system, and the right front wheel cylinder is respectively connected with the first pressure increasing valve and the first pressure reducing valve in the second hydraulic system.
The hydraulic system is ESP hydraulic system, ESP hydraulic system upper end is connected with the brake master cylinder through two interfaces, ESP hydraulic system's lower extreme is equipped with first interface, the second interface, third interface and fourth interface, wherein first interface is connected through first pipeline with the left rear wheel cylinder, be equipped with the trip valve on the first pipeline, the second interface is connected through the second pipeline with the right front wheel cylinder, be equipped with the trip valve on the second pipeline, the third interface is connected through the third pipeline with the left front wheel cylinder, be equipped with the trip valve on the third pipeline, the fourth interface is connected through the fourth pipeline with the right rear wheel cylinder, be equipped with the trip valve on the fourth pipeline, the second pipeline is connected through the fifth pipeline with the third pipeline, be equipped with first decoupling valve and second decoupling valve on the fifth pipeline, be connected with electronic liquid storage cylinder between first decoupling valve and the second decoupling valve.
The ESP hydraulic system is an assembly of existing equipment, and therefore, the specific model and specification are not further described.
The working principle of the invention is as follows:
the first embodiment is as follows:
when the power-assisted braking is needed, when a driver steps on a brake pedal, a motor in the electric power-assisted conversion mechanism provides power assistance, and the power assistance and a brake pedal push rod push a piston in a brake master cylinder together to press brake fluid in the piston into a hydraulic system loop. The first chamber of the brake master cylinder is connected with the first hydraulic system, the second chamber is connected with the second hydraulic system, regenerative braking acts on the driving shaft, the front shaft is used as the driving shaft, and the brake pipeline is arranged in an X shape, namely, the brake pipeline acts on a left front wheel cylinder of the first hydraulic system and a right front wheel cylinder of the second hydraulic system.
When pedal decoupling is needed, a motor in the electric power-assisted conversion mechanism provides braking power, a piston in the electric liquid storage cylinder moves to the right under the control of the motor of the liquid storage cylinder, meanwhile, two isolation valves in the first hydraulic system and the second hydraulic system are communicated, the two reversing valves are both positioned at the left position, the two liquid return valves are disconnected, brake liquid which should enter the right front wheel cylinder and the left front wheel cylinder enters the electric liquid storage cylinder, decoupling is achieved, and if the rear axle brake wheel cylinder does not need to enter the brake liquid, the cut-off valves in the first hydraulic system and the second hydraulic system are disconnected.
The electric power-assisted conversion mechanism is internally provided with a power-assisted motor and a set of transmission mechanism, the transmission mechanism converts the rotary motion of the output shaft of the motor into linear motion and transmits the power assistance of the motor to the push rod of the brake master cylinder.
The pedal feeling is obtained by adjusting the boosting of a motor in the electric boosting conversion mechanism, and when the motor in the electric boosting conversion mechanism fails, a push rod of the brake pedal overcomes idle stroke and is directly connected with a piston push rod of a brake master cylinder, so that manual braking can be performed.
The electric liquid storage cylinder is internally provided with a power assisting motor and a set of transmission mechanism, and the transmission mechanism converts the rotary motion of the output shaft of the motor into linear motion, so that the piston of the electric liquid storage cylinder is driven to move, and the volume of the electric liquid storage cylinder is changed. When the motor of the electric liquid storage cylinder fails, decoupling cannot be performed, at the moment, the two reversing valves in the first hydraulic system and the second hydraulic system are located at the right position, and the two liquid return valves are disconnected.
When the conventional braking and ABS braking working conditions are carried out, the two isolation valves in the first hydraulic system and the second hydraulic system are communicated, the two suction valves are disconnected, the two reversing valves are positioned on the right, namely, the ports A and B of the two reversing valves are communicated, the two cut-off valves are communicated, a plunger pump motor does not work, the motor of the electric liquid storage cylinder does not work, pedal decoupling is not carried out, brake fluid enters a brake cylinder from a brake main cylinder through the two isolation valves, the two reversing valves, the two cut-off valves, the two first pressure increasing valves and the two second pressure increasing valves, the wheel cylinder is pressurized when the two first pressure increasing valves and the two second pressure increasing valves are fully communicated, the wheel cylinder is depressurized when the pressure reducing valves are fully communicated, the ABS braking realizes pressurization, pressure maintaining and depressurization by controlling the high-speed opening and closing of the pressure increasing valves and the pressure reducing valves, the two processes have no regenerative braking participation, and if the regenerative braking working conditions are carried out when the conventional braking and the ABS braking working conditions are judged to be carried out, the regenerative braking working conditions should be withdrawn.
When an ESP braking working condition is carried out, two isolation valves in the first hydraulic system and the second hydraulic system are disconnected, two suction valves are communicated, two reversing valves are located on the right, namely openings A and B of the two reversing valves are communicated, two cut-off valves are communicated, a plunger pump motor works, a motor of an electric liquid storage cylinder does not work, pedal decoupling is not carried out, brake liquid enters a brake wheel cylinder from a brake main cylinder through the two suction valves, the two plunger pumps, the two second one-way valves, two dampers, the two reversing valves, the two cut-off valves, the two first booster valves and the two second booster valves, and the system can realize ESP braking by virtue of the booster valves, the pressure reducing valves, the two plunger pumps, the two energy accumulators and the plunger pump motor.
When the regenerative braking strength is enhanced and does not reach the maximum value, the regenerative braking participates in braking under the working condition, the two isolation valves in the first hydraulic system and the second hydraulic system are communicated, the two suction valves are disconnected, the two reversing valves are positioned on the left, namely, ports A and C of the two reversing valves are communicated, the two liquid return valves are disconnected, the two cut-off valves are disconnected, the plunger pump motor does not work, the motor of the electric liquid storage cylinder works to drive the piston of the liquid storage cylinder to move rightwards, so that the volume of the electric liquid storage cylinder is increased, when the motor in the electric power-assisted conversion mechanism pushes the piston in the brake main cylinder to move leftwards to press out brake liquid, the brake liquid enters the electric liquid storage cylinder through the two isolation valves and the two reversing valves in the first hydraulic system and the second hydraulic system, the volume of the electric liquid storage cylinder is increased by the same amount as the displacement amount of the brake liquid in the brake main cylinder, the value of the brake liquid is controlled according to a brake control strategy in the brake ECU, the brake liquid in the electric liquid storage cylinder is moved out because the brake liquid storage cylinder enters the electric liquid storage cylinder, the hydraulic pressure of the drive shaft is not increased, the brake liquid in the drive shaft, the wheel is not increased, the brake liquid is not generated in the drive shaft, and the brake liquid in the second hydraulic system is decoupled.
When the regenerative braking strength is kept under a working condition, the two isolation valves in the first hydraulic system and the second hydraulic system are communicated, the two suction valves are disconnected, the two reversing valves are positioned on the right, namely, the ports A and B of the two reversing valves are communicated, the two liquid return valves are disconnected, the two cut-off valves are communicated, the plunger pump motor does not work, the motor of the electric liquid storage cylinder does not work, the brake liquid in the electric liquid storage cylinder is continuously stored in the electric liquid storage cylinder, along with the increase of the braking strength, the piston of the brake main cylinder continuously moves to the left to press out the brake liquid, the newly pressed brake liquid enters the brake wheel cylinder through the two isolation valves, the two reversing valves, the two cut-off valves, the two first booster valves and the two second booster valves in the first hydraulic system and the second hydraulic system, the braking force of the wheel is increased, but the regenerative braking strength is kept unchanged.
When the regenerative braking strength is reduced and the total braking strength is not changed, the two isolation valves in the first hydraulic system and the second hydraulic system are communicated, the two suction valves are disconnected, the two reversing valves are positioned on the right, namely, ports A and B of the two reversing valves are communicated, the two liquid return valves are communicated, the two cut-off valves are communicated, the plunger pump motor does not work, the motor of the electric liquid storage cylinder works, the piston of the electric liquid storage cylinder moves to the left under the action of the motor in the electric liquid storage cylinder, the brake liquid in the electric liquid storage cylinder is pumped into a front wheel braking wheel cylinder through the two first booster valves, and is pumped into a rear wheel braking wheel cylinder through the two liquid return valves, the two reversing valves, the two cut-off valves and the two second booster valves, the reduction amount of the brake liquid in the electric liquid storage cylinder is determined by the regenerative braking strength determined by a braking control strategy, no new brake liquid is moved out from the braking main cylinder in the process, the brake liquid moved out by the electric liquid in the electric liquid storage cylinder enters the braking wheel cylinder, and the reduction amount of the regenerative braking strength is supplemented by the increase amount of the wheel braking strength so as to keep the total braking strength unchanged.
When the regenerative braking intensity is reduced and the total braking intensity is increased, namely the braking intensity required by a driver is increased, but the regenerative braking force limited by the system is reduced, the two isolation valves in the first hydraulic system and the second hydraulic system are communicated, the two suction valves are disconnected, the two reversing valves are positioned at the right position, namely, ports A and B of the two reversing valves are communicated, the two liquid return valves are communicated, the two cut-off valves are communicated, the two first pressure increasing valves and the two second pressure increasing valves are communicated, the plunger pump motor does not work, the motor of the electric liquid storage cylinder works, the brake liquid in the electric liquid storage cylinder enters the front wheel braking wheel cylinder through the two liquid return valves and the two first pressure increasing valves, the brake liquid enters the rear wheel braking wheel cylinder through the two liquid return valves, the two reversing valves, the two cut-off valves and the two second pressure increasing valves, the piston of the electric liquid storage cylinder moves to the left under the action of the motor in the electric liquid storage cylinder, the reduction amount of the brake liquid in the electric liquid storage cylinder is determined by the regenerative braking intensity determined by the braking control strategy, and simultaneously, the piston of the brake liquid master cylinder moves to the left, and the brake liquid is pressed into the braking loop, and the total braking force is increased.
When the regenerative braking intensity is reduced and the total braking intensity is reduced, namely the braking intensity required by a driver is reduced and the regenerative braking intensity is also reduced, the hydraulic pressure of a wheel cylinder is reduced firstly, the hydraulic braking intensity of the wheel cylinder is reduced, a piston of a brake master cylinder moves to the right, two isolation valves in a first hydraulic system and a second hydraulic system are communicated, two suction valves are disconnected, two reversing valves are located at the right position, namely ports A and B of the two reversing valves are communicated, two liquid return valves are disconnected, two cut-off valves are communicated, a plunger pump motor does not work, the motor of an electric liquid storage cylinder does not work, the two first pressure increasing valves and the two second pressure increasing valves are communicated, the two first pressure reducing valves and the two second pressure reducing valves are disconnected, and brake liquid in the brake wheel cylinder is sent back to the brake master cylinder through the two fourth one-way valves, the two fifth one-way valves, the two cut-off valves, the two reversing valves and the two first one-way valves.
When the regenerative braking strength is reduced and the total braking strength is reduced, namely when the braking strength required by a driver is reduced and the regenerative braking strength is also required to be reduced, after the hydraulic pressure of a wheel cylinder is reduced to zero, the piston of the brake master cylinder continues to move to the right, the brake fluid of the electric liquid storage cylinder is returned to the brake master cylinder, and the regenerative braking strength is reduced.
Embodiment two:
when the non-regenerative braking is carried out, the cut-off valves on the first pipeline, the second pipeline, the third pipeline and the fourth pipeline are communicated, the first decoupling valve and the second decoupling valve on the fifth pipeline are disconnected, the electric liquid storage cylinder does not work, namely the original path of the braking system is not changed, and conventional braking, ABS braking and ESP braking can be carried out according to control logic;
under the working condition that the regenerative braking strength is increased, the stop valves on the first pipeline, the second pipeline, the third pipeline and the fourth pipeline are all disconnected, the first decoupling valve and the second decoupling valve on the fifth pipeline are communicated, and the electric liquid storage cylinder works, so when a motor in the electric power-assisted conversion mechanism pushes a piston in the brake master cylinder to move leftwards to press out brake liquid, the brake liquid enters the electric liquid storage cylinder through the ESP hydraulic system, the first decoupling valve and the second decoupling valve on the fifth pipeline, the volume increase of the electric liquid storage cylinder is equal to the moving-out amount of the brake liquid in the brake master cylinder, the value of the volume increase is controlled according to a braking control strategy in the brake ECU, the brake liquid moved out from the brake master cylinder enters the electric liquid storage cylinder, the hydraulic pressure of the wheel is not increased, the wheel does not generate braking force, and the pedal decoupling of the wheel cylinder during regenerative braking is realized.
When the regenerative braking strength is kept, the cut-off valves on the first pipeline, the second pipeline, the third pipeline and the fourth pipeline are communicated, the first decoupling valve and the second decoupling valve on the fifth pipeline are disconnected, the electric liquid storage cylinder does not work, namely the original path of the braking system is not changed, the brake liquid of the electric liquid storage cylinder is continuously stored in the electric liquid storage cylinder, along with the increase of the braking strength, the piston of the brake main cylinder continuously moves leftwards to press out the brake liquid, the newly pressed brake liquid enters the wheel braking cylinder through the ESP hydraulic system, the first pipeline, the second pipeline, the third pipeline and the fourth pipeline, the braking force of the wheel is increased, but the regenerative braking strength is kept unchanged.
When the regenerative braking strength is reduced and the total braking strength is unchanged, the cut-off valves on the first pipeline, the second pipeline, the third pipeline and the fourth pipeline are communicated, the first decoupling valve and the second decoupling valve on the fifth pipeline are communicated, the electric liquid storage cylinder works, brake liquid in the electric liquid storage cylinder enters the right front wheel cylinder and the left front wheel cylinder through the cut-off valves on the second pipeline and the third pipeline, the brake liquid enters the left rear wheel cylinder and the right rear wheel cylinder through the second interface and the third interface, the first interface and the fourth interface at the lower end of the ESP hydraulic system, the cut-off valve on the first pipeline and the cut-off valve on the fourth pipeline, the reduction amount of the brake liquid in the electric liquid storage cylinder is determined by the regenerative braking strength determined by the braking control strategy, no new brake liquid is removed from the braking main cylinder in the process, the brake liquid removed from the electric liquid storage cylinder enters the braking wheel cylinders, and the reduction amount of the regenerative braking strength is supplemented by the increase amount of the wheel braking strength to keep the total braking strength unchanged.
When the regenerative braking strength is reduced and the total braking strength is increased, the cutoff valves on the first pipeline, the second pipeline, the third pipeline and the fourth pipeline are communicated, the first decoupling valve and the second decoupling valve on the fifth pipeline are communicated, the electric liquid storage cylinder works, a piston of the electric liquid storage cylinder moves leftwards under the action of a motor in the electric liquid storage cylinder, brake liquid is pressed into a braking loop through the first decoupling valve and the second decoupling valve on the fifth pipeline, the regenerative braking strength is reduced, the reduction amount of the brake liquid in the electric liquid storage cylinder is determined by the regenerative braking strength determined by a braking control strategy, meanwhile, a brake pedal is continuously stepped, the piston of a brake main cylinder moves leftwards, the brake liquid is pressed into the braking loop, and the total braking force is increased.
When the regenerative braking intensity is reduced and the total braking intensity is reduced, namely the braking intensity required by a driver is reduced and the regenerative braking intensity is also required to be reduced, the hydraulic pressure of the wheel cylinder is reduced firstly, namely the hydraulic braking intensity of the wheel cylinder is reduced, a piston of the brake master cylinder moves to the right, the cut-off valves on the first pipeline, the second pipeline, the third pipeline and the fourth pipeline are communicated, the first decoupling valve and the second decoupling valve on the fifth pipeline are disconnected, the electric liquid storage cylinder does not work, and the brake fluid in the brake wheel cylinder returns to the brake master cylinder through the ESP hydraulic system.
When the regenerative braking intensity is reduced and the total braking intensity is reduced, namely the braking intensity required by a driver is reduced and the regenerative braking intensity is also required to be reduced, after the hydraulic pressure of the wheel cylinder is reduced to zero, the piston of the brake master cylinder continues to move to the right, the cut-off valves on the first pipeline, the second pipeline, the third pipeline and the fourth pipeline are disconnected, the first decoupling valve and the second decoupling valve on the fifth pipeline are communicated, the electric liquid storage cylinder works, and the brake liquid in the electric liquid storage cylinder is pressed back to the brake master cylinder through the first decoupling valve and the second decoupling valve on the fifth pipeline and the ESP hydraulic system.
The invention has the beneficial effects that:
the braking system provided by the invention adopts the motor for assisting the braking, does not depend on vacuum, and can keep the pedal feeling similar to that of a vacuum booster; during regenerative braking, the pedal feeling can be kept unchanged by adjusting the power-assisted characteristic of the motor; the brake fluid displacement amount of the brake master cylinder is equal to the brake fluid inlet amount of the liquid storage cylinder by controlling the motor of the liquid storage cylinder, so that the control is more accurate; the cooperative braking of regenerative braking and friction braking is realized, and the braking energy can be recovered as much as possible.
Drawings
Fig. 1 is a schematic structural diagram of an embodiment of the present invention.
Fig. 2 is a schematic structural view of the electric power conversion mechanism of the present invention.
Fig. 3 is a schematic structural diagram of a second embodiment of the present invention.
1. Brake pedal 2, electric power-assisted conversion mechanism 3, brake master cylinder 4 and liquid storage tank
5. Electric liquid storage cylinder 6, hydraulic system 7, brake wheel cylinder 10 and booster motor
11. A primary gear 12, a secondary gear 13, a push rod 14, a ball screw 15 and a screw nut
16. Liquid storage cylinder 20, first hydraulic system 21, second hydraulic system 22 and isolation valve
23. Suction valve 24, plunger pump 25, shut-off valve 26, change valve 27, liquid return valve
28. A first pressure increasing valve 29, a second pressure increasing valve 30, a first pressure reducing valve 31, a second pressure reducing valve
32. First check valve 33, damper 34, second check valve 35, accumulator
36. A third one-way valve 37, a plunger pump motor 38, a fourth one-way valve 39, a fifth one-way valve
40. Left rear wheel cylinder 41, right front wheel cylinder 42, left front wheel cylinder 43, and right rear wheel cylinder
50. A first interface 51, a second interface 52, a third interface 54, and a fourth interface
55. First, second, third and fourth lines 56, 57, 58
59. A fifth line 60, a first decoupling valve 61, a second decoupling valve.
Detailed Description
The first embodiment is as follows:
please refer to fig. 1 and fig. 2:
the invention provides a decoupling type electric power-assisted braking system based on X-type arrangement, which comprises a brake pedal 1, an electric power-assisted conversion mechanism 2, a brake master cylinder 3, a liquid storage tank 4, an electric liquid storage tank 5, a hydraulic system 6 and a brake wheel cylinder 7, wherein a push rod of the brake pedal 1 is connected with an input end of the electric power-assisted conversion mechanism 2, an output end of the electric power-assisted conversion mechanism 2 is connected with a piston push rod of the brake master cylinder 3, the liquid storage tank 4 is connected on the brake master cylinder 3, and a connecting port in the hydraulic system 6 is respectively connected with the brake master cylinder 3, the electric liquid storage tank 5 and the brake wheel cylinder 7.
The electric power conversion mechanism 2 comprises a power motor 10, a primary gear 11, a secondary gear 12, a push rod 13, a ball screw 14, a screw nut 15 and a liquid storage cylinder 16, wherein the primary gear 11 is mounted on an output shaft of the power motor 10 and is externally meshed with the secondary gear 12, the secondary gear 12 is fixed on the screw nut 15 through keys, the screw nut 15 is driven by the secondary gear 12 to rotate so as to drive the ball screw 14 to do linear motion, the ball screw 14 is hollow, the right side of the ball screw 14 is provided with a bottom, the bottom of the ball screw is provided with a hole, the hole corresponds to the hole on the bottom of the right side of the push rod 13 one by one, the push rod 13 is fixed on the bottom of the right side of the ball screw 14 through bolts, so that the push rod 13 can be driven to do linear motion when the ball screw 14 moves, the bottom of the right side of the push rod 13 is provided with a threaded hole, the push rod can be fixed on the bottom of the right side of the ball screw 14 through bolts and the threaded hole, the left side of the push rod is connected with a piston in the liquid storage cylinder 16, and can drive the piston in the liquid storage cylinder 16 to do linear motion.
The hydraulic system 6 comprises a first hydraulic system 20 and a second hydraulic system 21, the first hydraulic system 20 and the second hydraulic system 21 are symmetrical, the first hydraulic system 20 and the second hydraulic system 21 both comprise an isolation valve 22, a suction valve 23, a plunger pump 24, a shut-off valve 25, a reversing valve 26, a liquid return valve 27, a first pressure increasing valve 28, a second pressure increasing valve 29, a first pressure reducing valve 30 and a second pressure reducing valve 31, wherein the isolation valve 22 is a normally open type on-off valve, one end of the isolation valve is connected with the brake master cylinder 3, one end of the isolation valve is connected with an A port of the reversing valve 26 and the shut-off valve 25, two ends of the isolation valve 22 are provided with a first check valve 32, an outlet end of the first check valve 32 is connected with the brake master cylinder 3, an outlet end of the plunger pump 24 is connected with the isolation valve 22 through a pipeline, a damper 33 and a second check valve 34 are arranged on the connecting pipeline, an outlet end of the second check valve 34 is arranged on one side of the damper 33, the inlet end of the plunger pump 24 is also connected with the first pressure reducing valve 30 and the second pressure reducing valve 31 through pipelines, an energy accumulator 35 and a third one-way valve 36 are arranged on the connecting pipelines, the outlet 36 of the third one-way valve is arranged on one side of the inlet of the plunger pump 24, the energy accumulator 35 is connected between the inlet end of the third one-way valve 36 and the first pressure reducing valve 30 and the second pressure reducing valve 31, the inlet end of the plunger pump 24 is also connected with the suction valve 23, the other end of the suction valve 23 is connected with the brake master cylinder 3, the plunger pumps 24 in the first hydraulic system 20 and the second hydraulic system 21 are driven by a common plunger pump motor 37, the reversing valve 26 is a two-position three-way valve, wherein the port A is connected with the isolating valve 22, the port B is connected with the first pressure increasing valve 28, the port C is connected with the liquid returning valve 27 and the electric liquid storage cylinder 5, the ports A and C are communicated to be in a left position, the ports A and B are communicated to be in a right position and are normal state, and the other end of the liquid returning valve 27 is also connected with the first pressure increasing valve 28, the electric liquid storage cylinder 5 is arranged on a pipeline which is connected with two liquid return valves 27 and two reversing valves 26 in the first hydraulic system 20 and the second hydraulic system 21, the two ends of the first pressure increasing valve 28 are provided with fourth one-way valves 38, the outlet ends of the fourth one-way valves 38 are arranged on one side of the reversing valves 26, the cut-off valve 25 is a normally open type cut-off valve, one end of the normally open type cut-off valve is connected with the outlet of the isolating valve 22, one end of the normally open type cut-off valve is connected with the inlet of the second pressure increasing valve 29, the two ends of the second pressure increasing valve 29 are provided with fifth one-way valves 39, and the outlet ends of the fifth one-way valves 39 are arranged on one side of the cut-off valve 25.
The first pressure increasing valve 28 and the second pressure increasing valve 29 are high-speed opening and closing valves and are normally open type valves, and the first pressure reducing valve 30 and the second pressure reducing valve 31 are high-speed opening and closing valves and are normally closed type valves.
The brake wheel cylinder 7 includes a left rear wheel cylinder 40, a right front wheel cylinder 41, a left front wheel cylinder 42 and a right rear wheel cylinder 43, wherein the left rear wheel cylinder 40 is respectively connected with the second pressure increasing valve 29 and the second pressure reducing valve 31 in the second hydraulic system 21, the right front wheel cylinder 41 is respectively connected with the first pressure increasing valve 28 and the first pressure reducing valve 30 in the second hydraulic system 21, the left front wheel cylinder 42 is respectively connected with the first pressure increasing valve 28 and the first pressure reducing valve 30 in the first hydraulic system 20, and the right rear wheel cylinder 43 is respectively connected with the second pressure increasing valve 29 and the second pressure reducing valve 31 in the first hydraulic system 20.
The working principle of the embodiment is as follows:
when the driver steps on the brake pedal 1 when needing assisted braking, the motor in the electric power conversion mechanism 2 provides assistance, and pushes the piston in the brake master cylinder 3 together with the push rod of the brake pedal 1, so that the brake fluid in the piston is pressed into a loop of the hydraulic system 6. The first chamber of the master cylinder 3 is connected to the first hydraulic system 20, the second chamber is connected to the second hydraulic system 21, regenerative braking acts on the drive shaft, and the front shaft is the drive shaft, and the brake pipe arrangement is of an X-type, that is, acts on the left front wheel cylinder 42 of the first hydraulic system 20 and the right front wheel cylinder 41 of the second hydraulic system 21.
When pedal decoupling is needed, braking assistance is provided by a motor in the electric power-assisted conversion mechanism 2, a piston in the electric liquid storage cylinder 5 moves to the right under the control of a liquid storage cylinder motor, meanwhile, the two isolation valves 22 in the first hydraulic system 20 and the second hydraulic system 21 are communicated, the two reversing valves 26 are both located at the left position, the two liquid return valves 27 are disconnected, brake liquid which should enter the right front wheel cylinder 41 and the left front wheel cylinder 42 enters the electric liquid storage cylinder 5, decoupling is achieved, and if brake liquid does not need to enter the rear axle brake wheel cylinder, the cutoff valves 25 in the first hydraulic system 20 and the second hydraulic system 21 are disconnected.
The electric power-assisted conversion mechanism 2 is internally provided with a power-assisted motor 10 and a set of transmission mechanism, the transmission mechanism converts the rotary motion of the output shaft of the motor into linear motion and transmits the power assistance of the motor to the push rod of the brake master cylinder 3.
The pedal feeling is obtained by adjusting the boosting size of the motor in the electric boosting conversion mechanism 2, and when the motor in the electric boosting conversion mechanism 2 fails, the push rod of the brake pedal 1 overcomes the idle stroke and then is directly connected with the piston push rod of the brake master cylinder 3, so that manual braking can be performed.
The electric liquid storage cylinder 5 comprises a power-assisted motor 10 and a set of transmission mechanism, and the transmission mechanism converts the rotary motion of an output shaft of the motor into linear motion, so that a piston of the electric liquid storage cylinder 5 is driven to move, and the volume of the electric liquid storage cylinder 5 is changed. When the motor of the electric liquid storage cylinder 5 fails, the decoupling cannot be realized, and at the moment, the two reversing valves 26 in the first hydraulic system 20 and the second hydraulic system 21 are positioned at the right position, and the two liquid return valves 27 are disconnected.
When the conventional braking and ABS braking conditions are carried out, the two isolation valves 22 in the first hydraulic system 20 and the second hydraulic system 21 are communicated, the two suction valves 23 are disconnected, the two reversing valves 26 are positioned on the right, namely, the ports A and B of the two reversing valves 26 are communicated, the two cut-off valves 25 are communicated, the plunger pump motor 37 does not work, the motor of the electric liquid storage cylinder 5 does not work and does not carry out pedal decoupling, brake liquid enters the brake wheel cylinder 7 from the brake main cylinder 3 through the two isolation valves 22, the two reversing valves 26, the two cut-off valves 25, the two first pressure increasing valves 28 and the two second pressure increasing valves 29, the wheel cylinder is pressurized when the two first pressure increasing valves 28 and the two second pressure increasing valves 29 are fully communicated, the wheel cylinder is depressurized when the two valves are fully communicated, the ABS braking realizes pressurization, pressure maintaining and depressurization by controlling the high-speed opening and closing of the pressure increasing valves and depressurization valves, the two processes do not involve regenerative braking, and if the regenerative braking conditions are judged to be carried out when the conventional braking and the ABS braking conditions are carried out, the regenerative braking conditions are carried out.
When an ESP braking condition is performed, the two isolation valves 22 in the first hydraulic system 20 and the second hydraulic system 21 are disconnected, the two suction valves 23 are communicated, the two reversing valves 26 are located on the right, that is, ports a and B of the two reversing valves 26 are communicated, the two cut-off valves 25 are communicated, the plunger pump motor 37 is operated, the motor of the electric liquid storage cylinder 5 does not operate, pedal decoupling is not performed, brake liquid enters the brake wheel cylinder 7 from the brake master cylinder 3 through the two suction valves 23, the two plunger pumps 24, the two second check valves 34, the two dampers 33, the two reversing valves 26, the two cut-off valves 25, the two first booster valves 28 and the two second booster valves 29, and the system can realize braking by virtue of the booster valves and the pressure reducing valves, the two plunger pumps 24, the two accumulators 35 and the plunger pump motor 37, and the system does not participate in ESP regenerative braking.
When the regenerative braking strength is enhanced and does not reach the maximum value, the regenerative braking participates in braking, the two isolation valves 22 in the first hydraulic system 20 and the second hydraulic system 21 are communicated, the two suction valves 23 are disconnected, the two reversing valves 26 are positioned at the left positions, namely, the ports A and C of the two reversing valves 26 are communicated, the two liquid return valves 27 are disconnected, the two cut-off valves 25 are disconnected, the plunger pump motor 37 does not work, the motor of the electric liquid storage cylinder 5 works to drive the piston of the liquid storage cylinder to move rightwards, so that the volume of the electric liquid storage cylinder 5 is increased, when the motor in the electric power-assisted conversion mechanism 2 pushes the piston in the brake main cylinder 3 to move leftwards to press brake fluid out, brake fluid enters the electric liquid storage cylinder 5 through the two isolation valves 22 and the two reversing valves 26 in the first hydraulic system 20 and the second hydraulic system 21, the volume increase amount of the electric liquid storage cylinder 5 is equal to the moving-out amount of the brake fluid in the brake master cylinder 3, the value of the volume increase amount of the electric liquid storage cylinder 5 is controlled according to a brake control strategy in the brake ECU, the brake fluid moving out of the brake master cylinder 3 enters the electric liquid storage cylinder 5, the hydraulic pressure of a wheel cylinder of a driving shaft wheel is not increased, the driving shaft wheel does not generate brake force, pedal decoupling during regenerative braking is achieved, at the moment, two cut-off valves 25 in the first hydraulic system 20 and the second hydraulic system 21 are disconnected, and no brake fluid exists in a rear wheel cylinder, so that no brake force is generated by a rear shaft.
When the regenerative braking strength is kept, the two isolation valves 22 in the first hydraulic system 20 and the second hydraulic system 21 are communicated, the two suction valves 23 are disconnected, the two reversing valves 26 are positioned on the right, namely, the ports a and B of the two reversing valves 26 are communicated, the two liquid return valves 27 are disconnected, the two cut-off valves 25 are communicated, the plunger pump motor 37 does not work, the motor of the electric liquid storage cylinder 5 does not work, the brake liquid in the electric liquid storage cylinder 5 is continuously stored in the electric liquid storage cylinder 5, the piston of the brake master cylinder 3 continuously moves to the left to press out the brake liquid along with the increase of the braking strength, the newly pressed brake liquid enters the brake wheel cylinder 7 through the two isolation valves 22, the two reversing valves 26, the two cut-off valves 25, the two first pressure increasing valves 28 and the two second pressure increasing valves 29 in the first hydraulic system 20 and the second hydraulic system 21, the braking force of the wheels is increased, but the regenerative braking strength is kept unchanged.
When the regenerative braking intensity is reduced and the total braking intensity is not changed, the two isolation valves 22 in the first hydraulic system 20 and the second hydraulic system 21 are communicated, the two suction valves 23 are disconnected, the two reversing valves 26 are positioned on the right, namely, ports A and B of the two reversing valves 26 are communicated, the two liquid return valves 27 are communicated, the two cut-off valves 25 are communicated, the plunger pump motor 37 does not work, the motor of the electric liquid storage cylinder 5 works, the piston of the electric liquid storage cylinder 5 moves to the left under the action of the motor in the electric liquid storage cylinder 5, the brake fluid in the electric liquid storage cylinder 5 is pumped into a front wheel braking wheel cylinder through the two first booster valves 28, the brake fluid in the electric liquid storage cylinder 5 is pumped into a rear wheel braking wheel cylinder through the two liquid return valves 27, the two reversing valves 26, the two cut-off valves 25 and the two second booster valves 29, the amount of the brake fluid in the electric liquid storage cylinder 5 is determined by the regenerative braking intensity determined by the braking control strategy, no new brake fluid is moved out of the brake master cylinder 3, the brake fluid moved out of the electric liquid storage cylinder 5 enters the braking wheel cylinder 7, the reduced amount of the regenerative braking intensity is supplemented by the total braking intensity, and the total braking wheel intensity is kept unchanged.
When the regenerative braking intensity is reduced and the total braking intensity is increased, i.e. the braking intensity required by the driver is increased, but the regenerative braking force limited by the system is reduced, the two isolation valves 22 in the first hydraulic system 20 and the second hydraulic system 21 are communicated, the two suction valves 23 are disconnected, the two reversing valves 26 are positioned on the right, i.e. the ports a and B of the two reversing valves 26 are communicated, the two liquid return valves 27 are communicated, the two cut-off valves 25 are communicated, the two first pressure increase valves 28 and the two second pressure increase valves 29 are communicated, the plunger pump motor 37 does not work, the motor of the electric reservoir 5 works, the brake fluid in the electric reservoir 5 enters the front wheel brake cylinder through the two liquid return valves 27 and the two first pressure increase valves 28, enters the rear wheel brake cylinder through the two liquid return valves 27, the two reversing valves 26, the two cut-off valves 25 and the two second pressure increase valves 29, the piston of the electric reservoir 5 is moved to the left under the action of the motor in the electric reservoir 5, the brake fluid reduction of the brake fluid is determined by the regenerative braking strategy of the brake pedal, the brake fluid in the brake fluid is pressed into the master cylinder 1, and the brake fluid continues to be increased, and the brake fluid is pressed into the brake fluid in the brake fluid circuit, and the master cylinder 3, and the brake fluid continues to be increased.
When the regenerative braking intensity is reduced and the total braking intensity is reduced, that is, when the braking intensity required by the driver is reduced and the regenerative braking intensity is also reduced, the wheel cylinder hydraulic pressure is reduced, the piston of the brake master cylinder 3 moves to the right, the two isolation valves 22 in the first hydraulic system 20 and the second hydraulic system 21 are communicated, the two suction valves 23 are disconnected, the two reversing valves 26 are positioned at the right position, that is, the ports a and B of the two reversing valves 26 are communicated, the two liquid return valves 27 are disconnected, the two cut-off valves 25 are communicated, the plunger pump motor 37 does not work, the motor of the electric liquid storage cylinder 5 does not work, the two first pressure increasing valves 28 and the two second pressure increasing valves 29 are communicated, the two first pressure reducing valves 30 and the two second pressure reducing valves 31 are disconnected, and the brake fluid in the brake wheel cylinder 7 is returned to the brake master cylinder 3 through the two fourth one-way valves 38 and the two fifth one-way valves 39, the two cut-off valves 25, the two reversing valves 26 and the two first one-way valves 32.
When the regenerative braking strength is reduced and the total braking strength is reduced, that is, when the braking strength required by the driver is reduced and the regenerative braking strength is also reduced, after the hydraulic pressure of the wheel cylinder is reduced to zero, the piston of the brake master cylinder 3 continues to move to the right, and then the brake fluid of the electric reservoir 5 is returned to the brake master cylinder 3, so as to reduce the regenerative braking strength, at this time, the piston of the brake master cylinder 3 continues to move to the right, the first hydraulic system 20 and the two isolation valves 22 in the second hydraulic system 21 are communicated, the two suction valves 23 are disconnected, the two reversing valves 26 are located at the left, that is, the ports a and C of the two reversing valves 26 are communicated, the two return valves 27 are disconnected, the two first pressure reducing valves 30 and the two second pressure reducing valves 31 are disconnected, the two first pressure increasing valves 28 and the two second pressure increasing valves 29 are communicated, the plunger pump motor 37 does not work, the motor of the electric reservoir 5 works, and the brake fluid in the brake fluid is compressed and braked by the two reversing valves 26 and the two first one-way check valves 22.
Example two:
please refer to fig. 2 and fig. 3:
the brake pedal 1, the electric power conversion mechanism 2, the brake master cylinder 3, and the liquid storage tank 4 in this embodiment are all the same as those in the first embodiment in terms of structure and connection relationship, and therefore specific structures and connection relationships are not further described, and the specific scheme in this embodiment is as follows:
the hydraulic system 6 is an ESP hydraulic system, the upper end of the ESP hydraulic system is connected with the master brake cylinder 3 through two interfaces, the lower end of the ESP hydraulic system is provided with a first interface 50, a second interface 51, a third interface 52 and a fourth interface 54, wherein the first interface 50 is connected with the left rear wheel cylinder 40 through a first pipeline 55, the first pipeline 55 is provided with a cut-off valve 25, the second interface 51 is connected with the right front wheel cylinder 41 through a second pipeline 56, the second pipeline 56 is provided with a cut-off valve 25, the third interface 52 is connected with the left front wheel cylinder 42 through a third pipeline 57, the third pipeline 57 is provided with the cut-off valve 25, the fourth interface 54 is connected with the right rear wheel cylinder 43 through a fourth pipeline 58, the fourth pipeline 58 is provided with the cut-off valve 25, the second pipeline 56 is connected with the third pipeline 57 through a fifth pipeline 59, the fifth pipeline 59 is provided with a first decoupling valve 60 and a second decoupling valve 61, and an electric liquid storage cylinder 5 is connected between the first decoupling valve 60 and the second decoupling valve 61.
The ESP hydraulic system is an assembly of existing equipment, and therefore, the specific model and specification are not further described.
The working principle of the embodiment is as follows:
when the non-regenerative braking is carried out, the cut-off valves 25 on the first pipeline 55, the second pipeline 56, the third pipeline 57 and the fourth pipeline 58 are communicated, the first decoupling valve 60 and the second decoupling valve 61 on the fifth pipeline 59 are disconnected, the electric liquid storage cylinder 5 does not work, and the original path of the braking system is not changed, so that the conventional braking, the ABS braking and the ESP braking can be carried out according to the control logic;
under the working condition that the regenerative braking strength is increased, the cut-off valves 25 on the first pipeline 55, the second pipeline 56, the third pipeline 57 and the fourth pipeline 58 are all disconnected, the first decoupling valve 60 and the second decoupling valve 61 on the fifth pipeline 59 are communicated, and the electric liquid storage cylinder 5 works, so when a motor in the electric power-assisted conversion mechanism 2 pushes a piston in the brake master cylinder 3 to move leftwards to press out brake liquid, the brake liquid enters the electric liquid storage cylinder 5 through the ESP hydraulic system and the first decoupling valve 60 and the second decoupling valve 61 on the fifth pipeline 59, the volume increase amount of the electric liquid storage cylinder 5 is equal to the displacement amount of the brake liquid in the brake master cylinder 3, the value is controlled according to a braking control strategy in the brake ECU, the brake liquid displaced by the brake master cylinder 3 enters the electric liquid storage cylinder 5, the wheel cylinder hydraulic pressure of the wheel is not increased, the wheel does not generate braking force, and realizes pedal decoupling during regenerative braking.
In the working condition of maintaining the regenerative braking strength, the cut-off valves 25 on the first pipeline 55, the second pipeline 56, the third pipeline 57 and the fourth pipeline 58 are all communicated, the first decoupling valve 60 and the second decoupling valve 61 on the fifth pipeline 59 are disconnected, the electric liquid storage cylinder 5 does not work, the brake liquid of the electric liquid storage cylinder 5 is continuously stored in the electric liquid storage cylinder, the piston of the brake master cylinder 3 continuously moves to the left to press out the brake liquid along with the increase of the braking strength, the newly pressed brake liquid enters the wheel braking cylinder 7 through the ESP hydraulic system, the first pipeline 55, the second pipeline 56, the third pipeline 57 and the fourth pipeline 58, the braking force of the wheel is increased, and the regenerative braking strength is maintained.
When the regenerative braking strength is reduced and the total braking strength is not changed, the shut-off valves 25 on the first pipeline 55, the second pipeline 56, the third pipeline 57 and the fourth pipeline 58 are communicated, the first decoupling valve 60 and the second decoupling valve 61 on the fifth pipeline 59 are communicated, the electric liquid storage cylinder 5 works, brake liquid in the electric liquid storage cylinder 5 enters the right front wheel cylinder 41 and the left front wheel cylinder 42 through the shut-off valves 25 on the second pipeline 56 and the third pipeline 57, the brake liquid in the electric liquid storage cylinder 5 enters the left rear wheel cylinder 40 and the right rear wheel cylinder 43 through the second interface 51 and the third interface 52 at the lower end of the ESP hydraulic system, the shut-off valves 25 on the first pipeline 55 and the fourth interface 25 on the fourth pipeline 58, the reduction amount of the brake liquid in the electric liquid storage cylinder 5 is determined by the regenerative braking strength determined by the braking control strategy, no new brake liquid in the process moves out from the brake master cylinder 3, the brake liquid in the electric liquid storage cylinder 5 enters the brake liquid 7, the reduction amount of the regenerative braking strength is supplemented by the braking strength of the wheels so as to keep the total braking strength.
Under the working condition that the regenerative braking strength is reduced and the total braking strength is increased, the first pipeline 55, the second pipeline 56, the third pipeline 57 and the cut-off valve 25 on the fourth pipeline 58 are communicated, the first decoupling valve 60 and the second decoupling valve 61 on the fifth pipeline 59 are communicated, the electric liquid storage cylinder 5 works, the piston of the electric liquid storage cylinder 5 moves to the left under the action of the motor in the electric liquid storage cylinder 5, brake liquid is pressed into the braking circuit through the first decoupling valve 60 and the second decoupling valve 61 on the fifth pipeline 59, the regenerative braking strength is reduced, the reduction amount of the brake liquid in the electric liquid storage cylinder 5 is determined by the regenerative braking strength determined by the braking control strategy, meanwhile, the brake pedal 1 is continuously stepped on, the piston of the brake master cylinder 3 moves to the left, the brake liquid is pressed into the braking circuit, and the total braking force is increased.
When the regenerative braking strength is reduced and the total braking strength is reduced, that is, when the braking strength required by the driver is reduced and the regenerative braking strength is also reduced, the wheel cylinder hydraulic pressure is reduced, that is, the braking strength of the wheel cylinder hydraulic pressure is reduced, the piston of the master cylinder 3 moves to the right, the cut-off valves 25 on the first pipeline 55, the second pipeline 56, the third pipeline 57 and the fourth pipeline 58 are communicated, the first decoupling valve 60 and the second decoupling valve 61 on the fifth pipeline 59 are disconnected, the electric reservoir 5 does not work, and the brake fluid in the brake wheel cylinder 7 is returned to the master cylinder through the ESP hydraulic system.
When the regenerative braking strength is reduced and the total braking strength is reduced, that is, when the braking strength required by the driver is reduced and the regenerative braking strength is also reduced, after the pressure drop of the wheel cylinder fluid is zero, the piston of the master cylinder 3 continues to move to the right, the cut valves 25 on the first, second, third and fourth pipelines 55, 56, 57 and 58 are disconnected, the first and second decoupling valves 60 and 61 on the fifth pipeline 59 are communicated, the electric reservoir 5 is operated, and the brake fluid therein is pressed back to the master cylinder 3 through the first and second decoupling valves 60 and 61 on the fifth pipeline 59 and the ESP hydraulic system.
Claims (2)
1. A decoupling type electric power-assisted brake system based on X-type arrangement comprises a brake pedal, an electric power-assisted conversion mechanism, a brake master cylinder, a liquid storage tank, an electric liquid storage cylinder, a hydraulic system and a brake wheel cylinder, wherein a push rod of the brake pedal is connected with an input end of the electric power-assisted conversion mechanism, an output end of the electric power-assisted conversion mechanism is connected with a piston push rod of the brake master cylinder, the liquid storage tank is connected onto the brake master cylinder, connectors are arranged in the hydraulic system and are respectively connected with the brake master cylinder, the electric liquid storage cylinder and the brake wheel cylinder, the electric power-assisted conversion mechanism comprises a power-assisted motor, a primary gear, a secondary gear, a push rod, a ball screw, a screw nut and a liquid storage cylinder, wherein the primary gear is arranged on an output shaft of the power-assisted motor, and mesh outward with the secondary gear, the secondary gear passes through the key to be fixed on screw nut, screw nut is rotatory under the secondary gear drives, thereby it is linear motion to drive ball, the inside cavity of ball, the right side has a bottom, it is porose on the bottom, with the hole one-to-one on the bottom surface of push rod right side, utilize the bolt to fix the push rod on the bottom surface on the inside right side of screw nut, thereby can drive the push rod when ball moves and be linear motion, push rod right side bottom threaded hole, usable bolt and threaded hole fix it on ball right side bottom, the piston in its left side and the stock solution jar links to each other, can drive the piston in the stock solution jar and be linear motion, its characterized in that: the hydraulic system comprises a first hydraulic system and a second hydraulic system which are of symmetrical structures, the first hydraulic system and the second hydraulic system respectively comprise an isolation valve, a suction valve, a plunger pump, a stop valve, a reversing valve, a liquid return valve, a first booster valve, a second booster valve, a first pressure reducing valve and a second pressure reducing valve, wherein the isolation valve is a normally open type on-off valve, one end of the isolation valve is connected with a brake master cylinder, one end of the isolation valve is connected with an A port of the reversing valve and the stop valve, the two ends of the isolation valve are provided with a first one-way valve, the outlet end of the first one-way valve is connected with the brake master cylinder, the outlet end of the plunger pump is connected with the isolation valve through a pipeline, a damper and a second one-way valve are arranged on a connecting pipeline, the outlet end of the second one-way valve is arranged on one side of the damper, the inlet end of the plunger pump is also connected with the first pressure reducing valve and the second pressure reducing valve through a pipeline, the connecting pipeline is provided with an energy accumulator and a third one-way valve, the outlet of the third one-way valve is arranged on one side of the inlet of the plunger pump, the energy accumulator is connected between the inlet end of the third one-way valve and the first pressure reducing valve and the second pressure reducing valve, the inlet end of the plunger pump is also connected with a suction valve, the other end of the suction valve is connected with a brake master cylinder, the plunger pumps in the first hydraulic system and the second hydraulic system are driven by a common plunger pump motor, the reversing valve is a two-position three-way valve, wherein an A port is connected with an isolating valve, a B port is connected with a first pressure increasing valve, a C port is connected with a liquid return valve and an electric liquid storage cylinder, the A port and the C port are communicated to be in a left position, the A port and the B port are communicated to be in a right position, the state is normal, the other end of the liquid return valve is also connected with the first pressure increasing valve, the electric liquid storage cylinder is arranged on the pipeline connecting the two liquid return valves and the two reversing valves in the first hydraulic system and the second hydraulic system, and the two ends of the first pressure increasing valve are provided with a fourth one-way valve, the outlet end of the fourth one-way valve is arranged on one side of the reversing valve, the stop valve is a normally-open type opening and closing valve, one end of the stop valve is connected to the outlet of the isolating valve, the other end of the stop valve is connected to the inlet of the second booster valve, fifth one-way valves are arranged at two ends of the second booster valve, and the outlet ends of the fifth one-way valves are arranged on one sides of the stop valves.
2. The decoupled electric power-assisted brake system based on the X-type arrangement of claim 1, characterized in that: the first pressure increasing valve and the second pressure increasing valve are high-speed switch valves and are normally open valves, and the first pressure reducing valve and the second pressure reducing valve are high-speed switch valves and are normally closed valves.
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| CN201611161795.XA CN106696938B (en) | 2016-12-15 | 2016-12-15 | Decoupling type electric power-assisted braking system based on X-shaped arrangement |
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| CN201611161795.XA CN106696938B (en) | 2016-12-15 | 2016-12-15 | Decoupling type electric power-assisted braking system based on X-shaped arrangement |
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| CN106696938B true CN106696938B (en) | 2023-03-21 |
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| DE102009000781A1 (en) * | 2009-02-11 | 2010-08-12 | Robert Bosch Gmbh | Method for operating a hydraulic, a anti-lock control device having vehicle brake system |
| CN102114834B (en) * | 2011-02-15 | 2013-02-13 | 清华大学 | X-type pipeline layout energy feedback type hydraulic antilock brake system for electric vehicle |
| CN102795216A (en) * | 2012-08-02 | 2012-11-28 | 浙江亚太机电股份有限公司 | Hydraulic unit for integrated automobile brake system |
| CN202716864U (en) * | 2012-08-02 | 2013-02-06 | 浙江亚太机电股份有限公司 | Integrated hydraulic unit of automobile braking system |
| CN104097623B (en) * | 2014-08-06 | 2016-08-31 | 邓伟文 | A kind of integrated electro-hydraulic brake system of vehicle |
| CN206243157U (en) * | 2016-12-15 | 2017-06-13 | 吉林大学 | A kind of decoupling type electric booster braking system based on X-type arrangement |
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