CN111267807B - Fully-decoupled electronic/hydraulic power assisting system for regenerative braking of electric automobile - Google Patents
Fully-decoupled electronic/hydraulic power assisting system for regenerative braking of electric automobile Download PDFInfo
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- CN111267807B CN111267807B CN202010102532.1A CN202010102532A CN111267807B CN 111267807 B CN111267807 B CN 111267807B CN 202010102532 A CN202010102532 A CN 202010102532A CN 111267807 B CN111267807 B CN 111267807B
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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
- B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
- B60T8/32—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration
- B60T8/34—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration having a fluid pressure regulator responsive to a speed condition
- B60T8/40—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration having a fluid pressure regulator responsive to a speed condition comprising an additional fluid circuit including fluid pressurising means for modifying the pressure of the braking fluid, e.g. including wheel driven pumps for detecting a speed condition, or pumps which are controlled by means independent of the braking system
- B60T8/4072—Systems in which a driver input signal is used as a control signal for the additional fluid circuit which is normally used for braking
- B60T8/4081—Systems with stroke simulating devices for driver input
- B60T8/409—Systems with stroke simulating devices for driver input characterised by details of the stroke simulating device
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
- B60T13/00—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems
- B60T13/10—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release
- B60T13/12—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release the fluid being liquid
- B60T13/14—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release the fluid being liquid using accumulators or reservoirs fed by pumps
- B60T13/148—Arrangements for pressure supply
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
- B60T13/00—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems
- B60T13/10—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release
- B60T13/58—Combined or convertible systems
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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
- B60T17/00—Component parts, details, or accessories of power brake systems not covered by groups B60T8/00, B60T13/00 or B60T15/00, or presenting other characteristic features
- B60T17/18—Safety devices; Monitoring
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
- B60T7/00—Brake-action initiating means
- B60T7/12—Brake-action initiating means for automatic initiation; for initiation not subject to will of driver or passenger
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- Engineering & Computer Science (AREA)
- Transportation (AREA)
- Mechanical Engineering (AREA)
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- Regulating Braking Force (AREA)
Abstract
The invention belongs to the field of brake boosting systems, and relates to a fully-decoupled electronic/hydraulic boosting system for regenerative braking of an electric automobile, which comprises a pedal energy recycling mechanism and a motor boosting mechanism; the energy of a driver stepping on a brake pedal is converted into pressure energy by a small hydraulic cylinder in a pedal energy recycling mechanism and stored in an energy accumulator, high-pressure oil in the energy accumulator participates in the establishment of brake pressure under certain conditions, and a simulation spring is used for simulating the traditional pedal feel; the motor boosting mechanism pushes the main cylinder pedal to establish braking pressure through the transmission mechanism. The invention is suitable for the regenerative braking system and the active braking system of the electric automobile, and can keep the pedal feeling unchanged in the braking process; the energy of a driver stepping on the brake pedal can be stored and utilized, and the energy utilization rate of a brake system can be obviously improved in the long-term use process; the method has a safety backup function under the condition of failure.
Description
Technical Field
The invention belongs to the field of brake boosting systems, and relates to a fully-decoupled electronic/hydraulic boosting system for regenerative braking of an electric automobile.
Background
With the continuous popularization of electric vehicles and the development of regenerative braking systems, brake boosting systems based on vacuum boosters in traditional vehicles cannot be applied to electric vehicles with regenerative braking systems, and various novel electronic boosting braking systems aiming at the electric vehicles and the regenerative braking systems are developed. At present, the mainstream electronic power-assisted braking systems can be structurally divided into non-decoupling type electronic power-assisted braking systems and decoupling type electronic power-assisted braking systems.
In a non-decoupling electronic power-assisted brake system, the motor power assistance and the pedal force are rigidly combined and jointly act on a push rod of a brake main cylinder to realize the power assistance function. During braking, pedal force and motor assist interact. The non-decoupling type electronic power-assisted system can simulate the traditional pedal force-displacement relation under the normal working condition through some mechanism designs, but in some conditions, such as ABS pressure reduction working conditions and regenerative braking pressure reduction working conditions, the master cylinder pressure can generate large fluctuation, the feedback force on the pedal is influenced, and the phenomenon of 'kicking' occurs. At the moment, a set of power-assisted motor control strategy is usually designed for the non-decoupling type electronic power-assisted brake system, and feedback force fluctuation on the pedal is restrained by applying motor compensation torque, so that the phenomenon of 'pedaling' is restrained. The solution increases the complexity of the control part of the electronic power-assisted system, increases the energy consumption by frequently calling the motor, and reduces the energy recovery rate of the regenerative braking system to a certain extent.
In a decoupled electronic power-assisted brake system, a stroke simulator is generally used to simulate the traditional pedal feel and absorb high-pressure brake fluid, but the energy generated by manually treading a brake pedal in the braking process is not utilized.
In summary, in order to simplify the complexity of the control part, reduce the energy consumption of the operation of the power-assisted motor, fully utilize the energy generated by manpower, and improve the comprehensive energy recovery rate of the regenerative braking system of the electric vehicle, a set of novel electronic power-assisted braking system with the advantages of a comprehensive decoupling type power-assisted system and a non-decoupling type power-assisted system needs to be designed.
Disclosure of Invention
In view of the above, an object of the present invention is to provide a fully decoupled electronic/hydraulic power assisting system for regenerative braking of an electric vehicle, which is capable of decoupling a brake pedal displacement from a master cylinder pressure, storing energy obtained by manually stepping on the brake pedal, simulating a relationship between a conventional brake pedal displacement and a pedal force, and having a safety backup function in case of failure.
In order to achieve the purpose, the invention provides the following technical scheme:
the fully-decoupled electronic/hydraulic power assisting system for regenerative braking of the electric automobile comprises a pedal push rod, a simulation cavity end cover, a simulation cavity shell, a main shell, a motor, a pinion, a bearing, a first check valve, a two-position three-way valve I, a liquid storage tank, an energy accumulator reversing valve, a two-position three-way valve II, a two-position three-way valve III, a second check valve, a third check valve, a second loop reversing valve, a first loop reversing valve, a brake main cylinder, a main cylinder end cover, a main cylinder push rod, a large gear, a ball screw I, a ball screw II, a small hydraulic cylinder push rod, a second simulation spring, a recovery cavity shell and a first simulation spring; one end of the simulation cavity push rod is inserted into the pedal push rod and is fixedly connected with the pedal push rod, and the other end of the simulation cavity push rod is inserted into the simulation cavity shell; the simulation cavity end cover is fixedly arranged on one side of the simulation cavity shell inserted into the simulation cavity push rod; the first simulation spring is arranged between the simulation cavity push rod and the simulation cavity shell, and the diameter of the end face, facing the first simulation spring, of the simulation cavity push rod is larger than the inner diameter of the first simulation spring; the simulation cavity shell is fixedly connected with a push rod of the small hydraulic cylinder; the second simulation spring is coaxial with the push rod of the small hydraulic cylinder and is arranged between the simulation cavity shell and the small hydraulic cylinder; the small hydraulic cylinder is fixedly connected with the recovery cavity shell; the end surface of the recovery cavity shell is fixedly connected with the main shell; the ball screw II is matched with the ball screw I for installation; the ball screw I is arranged on the main shell through a bearing; the bull gear is coaxially arranged on the ball screw I; the small gear is arranged on the main shell through a bearing and is meshed with the large gear; the motor is arranged on the main shell, and an output shaft of the motor is coaxially connected with the pinion; the left end of the main cylinder push rod is fixedly connected with a ball screw II; the brake master cylinder is fixedly arranged on the main shell through a master cylinder end cover; the liquid storage tank is arranged on the brake master cylinder and is connected with the two oil inlets of the brake master cylinder; the oil inlet hole of the small hydraulic cylinder is connected to the liquid storage tank through a hydraulic pipeline; the oil outlet of the small hydraulic cylinder is sequentially connected to the first check valve and the two-position three-way valve I through hydraulic pipelines; two outlets of the two-position three-way valve I are respectively connected to the energy accumulator and the two-position three-way valve II; one outlet of the two-position three-way valve II is connected with the front brake circuit and the rear brake circuit, and the other outlet of the two-position three-way valve II is connected to the liquid storage tank; a branch outlet of the accumulator is connected to an accumulator reversing valve; a reversing valve of the energy accumulator is connected to a two-position three-way valve III; one outlet of the two-position three-way valve III is respectively connected to the front brake circuit and the rear brake circuit through a second check valve and a third check valve, and the other outlet of the two-position three-way valve III is connected to the liquid storage tank; two oil outlets of the brake master cylinder are respectively connected to the front brake circuit and the rear brake circuit through a first circuit reversing valve and a second circuit reversing valve.
Optionally, an extension section is further disposed at one end of the simulation cavity push rod facing the first simulation spring, and the outer diameter of the extension section is smaller than the inner diameter of the first simulation spring, extends into the first simulation spring, and is used for limiting when the simulation cavity push rod moves.
Optionally, the first simulation spring is a linear cylindrical coil spring, the stiffness of the first simulation spring is unchanged, the second simulation spring is a nonlinear conical coil spring, the stiffness of the second simulation spring is changeable, the minimum value of the stiffness of the second simulation spring is equal to the stiffness value of the first simulation spring, and the maximum value of the stiffness of the second simulation spring is greater than the stiffness value of the first simulation spring.
Optionally, the distance between the simulation cavity push rod and the contact surface of the first simulation spring and the bottom surface of the simulation cavity shell is shorter than the natural length of the first simulation spring.
Optionally, the two sides of the pedal push rod are provided with branched structures, the two sides of the recovery cavity shell are provided with grooves, the sizes of the grooves in the two sides of the recovery cavity shell are larger than those of the branched structures in the two sides of the pedal push rod, and the branched structures in the two sides of the pedal push rod are guaranteed to move in the grooves in the two sides of the recovery cavity shell.
Optionally, the energy of the driver stepping on the brake pedal is converted into the pressure energy of the brake oil through the small hydraulic cylinder and stored in the accumulator.
The invention has the beneficial effects that:
1. the system can realize the complete decoupling of the pressure of the brake pedal and the brake master cylinder, and no matter how the friction braking force and the pressure of the brake master cylinder change in the regenerative braking process, the feedback force on the brake pedal is not influenced, and the pedal feeling is kept unchanged.
2. The system can recover and store the energy of the manual treading of the brake pedal, can utilize high-pressure oil in the energy accumulator to establish brake pressure when the pressure in the energy accumulator reaches a certain threshold value, and can accurately provide required friction braking force by matching with high-speed switching valves of ABS/ESC systems and the like, thereby improving the energy utilization rate.
3. In the regenerative braking process, the motor does not need to compensate the feedback force of the brake pedal, so that the use frequency of the motor is reduced, the complexity of a motor control strategy is reduced, and the energy utilization rate is improved.
4. The system is highly suitable for an active braking system of an intelligent automobile. In the process of active braking, the motor can drive the main cylinder to build braking pressure, and the energy accumulator can also provide the braking pressure, and the brake pedal does not act in the process, so that a driver does not perceive the braking pressure.
5. The system can realize free adjustment of different boosting ratios, and the boosting ratio can be freely adjusted only by adjusting a motor control strategy because the pressure of the brake pedal and the pressure of the main cylinder are completely decoupled.
6. The system can select the rigidity of the second simulation spring 28 and the rigidity of the first simulation spring 30 according to the requirements of different vehicle types, so that different pedal displacement-pedal force relations are generated, namely different pedal feelings are generated, the change among different vehicle types is small, and the change is convenient.
7. The energy accumulator link of the system can be used as a first safety backup mechanism, and provides certain brake pressure when the motor fails to work.
8. The system is provided with a second safety backup mechanism, when the motor assistance and the energy accumulator are failed, the pedal push rod can directly push the ball screw II, so that a main cylinder push rod fixedly connected with the pedal push rod is pushed to establish braking pressure, meanwhile, the two-position three-way valve I is communicated with a lower outlet, the two-position three-way valve II is communicated with an upper outlet, and the pedal push rod pushes the small hydraulic cylinder to jointly establish the braking pressure, so that the braking process is accelerated.
Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention may be realized and attained by the means of the instrumentalities and combinations particularly pointed out hereinafter.
Drawings
For the purposes of promoting a better understanding of the objects, aspects and advantages of the invention, reference will now be made to the following detailed description taken in conjunction with the accompanying drawings in which:
FIG. 1 is a schematic view of the overall structure of the present invention;
FIG. 2 is a schematic diagram of the principles of the present invention;
FIG. 3 is a schematic diagram of an electric/hydraulic booster;
FIG. 4 is a partially enlarged schematic view of the simulation chamber;
fig. 5 is a schematic diagram of the relative movement positions of the pedal push rod, the recovery cavity shell and the ball screw II when the safety backup mechanism works.
Detailed Description
The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention. It should be noted that the drawings provided in the following embodiments are only for illustrating the basic idea of the present invention in a schematic way, and the features in the following embodiments and examples may be combined with each other without conflict.
Wherein the showings are for the purpose of illustrating the invention only and not for the purpose of limiting the same, and in which there is shown by way of illustration only and not in the drawings in which there is no intention to limit the invention thereto; to better illustrate the embodiments of the present invention, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of an actual product; it will be understood by those skilled in the art that certain well-known structures in the drawings and descriptions thereof may be omitted.
The same or similar reference numerals in the drawings of the embodiments of the present invention correspond to the same or similar components; in the description of the present invention, it should be understood that if there is an orientation or positional relationship indicated by terms such as "upper", "lower", "left", "right", "front", "rear", etc., based on the orientation or positional relationship shown in the drawings, it is only for convenience of description and simplification of description, but it is not an indication or suggestion that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes, and are not to be construed as limiting the present invention, and the specific meaning of the terms may be understood by those skilled in the art according to specific situations.
Referring to fig. 1-5, the reference numbers in the figures refer to the following elements: the device comprises a pedal push rod 1, a simulation cavity push rod 2, a simulation cavity end cover 3, a simulation cavity shell 4, a main shell 5, a motor 6, a pinion 7, a bearing 8, a first check valve 9, a two-position three-way valve I10, a liquid storage tank 11, an energy accumulator 12, an energy accumulator reversing valve 13, a two-position three-way valve II 14, a two-position three-way valve III 15, a second check valve 16, a third check valve 17, a second loop reversing valve 18, a first loop reversing valve 19, a brake master cylinder 20, a master cylinder end cover 21, a master cylinder push rod 22, a large gear 23, a ball screw I24, a ball screw II 25, a small hydraulic cylinder 26, a small hydraulic cylinder push rod 27, a second simulation spring 28, a recovery cavity shell 29 and a first simulation spring 30.
The invention relates to a fully-decoupled electronic/hydraulic power-assisted system for regenerative braking of an electric automobile, which comprises a pedal push rod 1, a simulation cavity push rod 2, a simulation cavity end cover 3, a simulation cavity shell 4, a main shell 5, a motor 6, a pinion 7, a bearing 8, a first check valve 9, a two-position three-way valve I10, a liquid storage tank 11, an energy accumulator 12, an energy accumulator reversing valve 13, a two-position three-way valve II 14, a two-position three-way valve III 15, a second check valve 16, a third check valve 17, a second loop reversing valve 18, a first loop reversing valve 19, a brake master cylinder 20, a master cylinder end cover 21, a master cylinder push rod 22, a large gear 23, a ball screw I24, a ball screw II 25, a small hydraulic cylinder 26, a small hydraulic cylinder push rod 27, a second simulation spring 28, a recovery cavity shell 29 and a first simulation spring 30. The left end of the simulation cavity push rod 2 is inserted into the pedal push rod 1 and fixedly connected with the pedal push rod; the right end of the simulation cavity push rod 2 extends into the simulation cavity shell 4; the simulation cavity end cover 3 is fixedly arranged on the left end face of the simulation cavity shell 4; the first simulation spring 30 is arranged between the simulation cavity push rod 2 and the simulation cavity shell 4; the major diameter of the right end of the simulation cavity push rod 2 is larger than the inner diameter of the first simulation spring 30, so that the simulation cavity push rod 2 can push the first simulation spring 30 to compress when moving in the simulation cavity shell 4; the right end of the simulation cavity push rod 2 is provided with a part with the diameter smaller than the inner diameter of the first simulation spring 30, and the part extends into the first simulation spring 30 and plays a role in limiting when the simulation cavity push rod 2 moves; the simulation cavity shell 4 is fixedly connected with a small hydraulic cylinder push rod 27; the second simulation spring 28 is coaxial with the small hydraulic cylinder push rod 27 and is arranged between the simulation cavity shell 4 and the small hydraulic cylinder 26; the small hydraulic cylinder 26 is fixedly connected with a recovery cavity shell 29; the left end surface of the recovery cavity shell 29 is fixedly connected with the main shell 5; the ball screw II 25 is matched with the ball screw I24 for installation; the ball screw I24 is arranged on the main shell 5 through a bearing 8; the bull gear 23 is coaxially arranged on the ball screw I24; the small gear 7 is arranged on the main shell 5 through a bearing and is meshed with the large gear 23; the motor 6 is arranged on the main shell 5, and the output shaft of the motor is coaxially connected with the pinion 7; the left end of the main cylinder push rod 22 is fixedly connected with a ball screw II 25; the brake master cylinder 20 is fixedly arranged on the main shell 5 through a master cylinder end cover 21; the liquid storage tank 11 is arranged on the brake master cylinder 20 and is connected with two oil inlets of the brake master cylinder 20; the left oil inlet hole above the small hydraulic cylinder 26 is connected to the liquid storage tank 11 through a hydraulic pipeline; the right oil outlet hole above the small hydraulic cylinder 26 is sequentially connected to the first check valve 9 and the two-position three-way valve I10 through hydraulic pipelines; two outlets of the two-position three-way valve I10 are respectively connected to the energy accumulator 12 and the two-position three-way valve II 14; one outlet of the two-position three-way valve II 14 is connected with the front brake circuit and the rear brake circuit, and the other outlet is connected to the liquid storage tank 11; the outlet of the right branch of the accumulator 12 is connected to an accumulator reversing valve 13; the accumulator reversing valve 13 is connected to a two-position three-way valve III 15; one outlet of the two-position three-way valve III 15 is respectively connected to the front and rear brake circuits through a second check valve 16 and a third check valve 17, and the other outlet is connected to the liquid storage tank 11; the two oil outlets of the brake master cylinder 20 are connected to the front and rear brake circuits through a first circuit directional control valve 19 and a second circuit directional control valve 18 respectively.
The first simulation spring 30 is a linear cylindrical spiral spring with constant rigidity, the second simulation spring 28 is a nonlinear conical spiral spring with variable rigidity, the minimum rigidity of the second simulation spring 28 is equal to the rigidity of the first simulation spring 30, the maximum rigidity of the second simulation spring 28 is far greater than the rigidity of the first simulation spring 30, and the first simulation spring and the second simulation spring present mechanical characteristics of softness and hardness in the compression process so as to simulate the relationship between the traditional pedal displacement and the pedal force.
The distance between the contact surface of the simulation cavity push rod 2 and the first simulation spring 30 and the bottom surface of the simulation cavity shell 4 is shorter than the natural length of the first simulation spring 30, so that the first simulation spring 30 in the installation position is in a compressed state, and the generated pretightening force is equal to the initial power of the traditional booster.
The two horizontal sides of the pedal push rod 1 are provided with branched structures, the two horizontal sides of the recovery cavity shell 29 are provided with grooves, the sizes of the grooves on the two horizontal sides of the recovery cavity shell 29 are larger than those of the branched structures on the two horizontal sides of the pedal push rod 1, and the branched structures on the two horizontal sides of the pedal push rod 1 can move in the grooves on the two horizontal sides of the recovery cavity shell 29, as shown in fig. 5.
The small hydraulic cylinder 26 converts energy of manual operation of the brake pedal into pressure energy of brake fluid, stores the pressure energy in the accumulator 12, and releases the pressure energy for use when necessary.
The working principle of the invention is as follows:
1. pedal energy recovery mode
When the brake system is in a pedal energy recovery mode, an outlet above the two-position three-way valve I10 is connected, the energy accumulator reversing valve 13 is disconnected, the second loop reversing valve 18 is opened, and the first loop reversing valve 19 is opened. The driver steps on the brake pedal, and the pedal force acts on the small hydraulic cylinder push rod 27 through the pedal push rod 1, the simulation cavity push rod 2, the first simulation spring 30 and the simulation cavity shell 4. The small cylinder push rod 27 is forced to begin squeezing the brake fluid in the small cylinder 26. The brake fluid in the small hydraulic cylinder 26 cannot open the first check valve 9 into the accumulator 12 until the pressure in the small hydraulic cylinder 26 is greater than the pressure in the accumulator 12, while the small cylinder push rod 27 temporarily cannot move to the right due to the incompressibility of the brake fluid. Meanwhile, when the pedal force is lower than the pretightening force of the first simulation spring 30, the pedal push rod 1 cannot move rightwards, and the mechanism can filter out slight disturbance on the brake pedal. When the pedal force is larger than the pretightening force of the first simulation spring 30, the pedal push rod 1 starts to push the simulation cavity push rod 2 to move rightwards, and the simulation cavity push rod 2 moves rightwards so as to compress the first simulation spring 30 to move rightwards. When the pressure of the brake oil in the small hydraulic cylinder 26 is greater than the pressure in the energy accumulator 12, the push rod 27 of the small hydraulic cylinder starts to move rightwards to squeeze the brake oil into the energy accumulator 12 through the first check valve 9 and the two-position three-way valve I10, so that the process of converting the energy of the brake pedal stepped by the driver into hydraulic energy in the storage capacity is completed, and meanwhile, the simulation cavity shell 4 fixedly connected with the push rod 27 of the small hydraulic cylinder starts to move rightwards synchronously to compress the second simulation spring 28.
Since the volume of oil pressed into the accumulator 12 during a single braking operation is small, the pressure rise in the accumulator 12 is small, and the hydraulic pressure of the hydraulic oil in the accumulator acting on the push rod 27 of the small hydraulic cylinder remains substantially constant.
Since the hydraulic pressure of the hydraulic oil in the accumulator acting on the push rod 27 of the small hydraulic cylinder is basically kept unchanged, the force change on the right side during the rightward movement of the simulation cavity shell 4 is only related to the rigidity of the second simulation spring 28. The minimum stiffness of the second simulation spring is equal to the stiffness of the first simulation spring, and the maximum stiffness of the second simulation spring is far greater than the stiffness of the first simulation spring, so that the pedal feedback force can be provided by the first simulation spring and the second simulation spring which are connected in series in the braking process. Because the second simulation spring is a nonlinear spring, the pedal feedback force is linearly changed when the pedal displacement is small in the braking process and is nonlinearly changed when the pedal displacement is large, and the pedal force has the characteristic of softness before hardness and is similar to the boosting characteristic of the traditional vacuum booster.
The above process can be performed for any pressure in the accumulator 12, so that the initial pressure of the accumulator 12 can be set lower to recover the pedal energy to a greater extent, and pedal energy recovery can be performed after the pressure in the accumulator is increased due to multiple times of braking, while the pedal feel is kept unchanged.
In the pedal energy recovery mode, the motor 6 drives the pinion 7 coaxially connected with the motor to rotate, the pinion 7 drives the gearwheel 23 meshed with the pinion 7 to rotate, the gearwheel 23 drives the ball screw I24 fixedly installed with the gearwheel to rotate, the ball screw I24 pushes the ball screw II 25 to move rightwards, so that the main cylinder push rod 22 is pushed to move rightwards, and the main cylinder push rod 22 moves rightwards to complete the establishment of braking pressure in a braking circuit.
In the pedal energy recovery mode, the brake pedal is completely decoupled from the pressure of the main cylinder, no matter how large the pressure of the main cylinder is required, the displacement and the stress of the brake pedal are not influenced, and the motor only needs to generate the required target torque.
2. Accumulator pressure braking mode
When the brake system is in the accumulator pressure braking mode, the system first detects the accumulator 12 pressure, and when the accumulator 12 pressure is within a preset threshold range, it is confirmed that the accumulator pressure braking mode is entered. An outlet above a two-position three-way valve I10 is communicated, an energy accumulator reversing valve 13 is communicated, an outlet above a two-position three-way valve III 15 is communicated, a second loop reversing valve 18 is disconnected, a first loop reversing valve 19 is disconnected, at the moment, the energy accumulator 12 is respectively communicated with front and rear hydraulic braking loops through the energy accumulator reversing valve 13, the two-position three-way valve III 15, a second check valve 16 and a third check valve 17, the motor 6 does not work in the braking process, the energy accumulator 12 builds braking pressure, and the wheel shift pressure of each wheel cylinder is accurately controlled through a lower ABS/ESC pressure adjusting mechanism.
3. Active braking mode
When the system is in an active braking mode, the system firstly detects the pressure in the energy accumulator 12, if the pressure of brake oil in the energy accumulator 12 is within a preset range, the energy accumulator reversing valve 13 is opened, the two-position three-way valve III 15 is connected with an upper outlet, the second loop reversing valve 18 and the first loop reversing valve 19 are disconnected, the high-pressure oil in the energy accumulator 12 provides braking pressure, the pressure of each brake wheel cylinder is accurately controlled through high-speed switching valves in the ABS/ESC system, and the active braking process is completed. If the pressure of the high-pressure brake oil in the energy accumulator 12 is lower than the preset range, the energy accumulator reversing valve 13 is closed, the second loop reversing valve 18 and the first loop reversing valve 19 are opened, the brake master cylinder is driven by the motor 6 to build brake pressure, and the active brake process is completed.
The brake pedal does not move during the active braking process, so that the driver is unaware of the movement.
4. Secure backup mechanism
When the system is in a safe backup mechanism, it is usually the case that the motor 6 fails and fails to operate. At the moment, the system detects the pressure in the energy accumulator 12, if the pressure of high-pressure brake oil in the energy accumulator 12 is within a preset range, the energy accumulator reversing valve 13 is opened, the two-position three-way valve III 15 is connected with an upper outlet, the second loop reversing valve 18 is disconnected with the first loop reversing valve 19, the high-pressure oil in the energy accumulator 12 provides brake pressure, the pressure of each brake wheel cylinder is accurately controlled through high-speed switch valves in systems such as an ABS/ESC (anti-lock braking system/electronic stability control) system, and the first safety backup braking process is completed. If the pressure of the brake oil in the energy accumulator 12 is lower than a preset range or all electronic components in the brake system are completely out of work, the second loop directional control valve 18 and the first loop directional control valve 19 are in a normally open initial state, a driver deeply steps on a brake pedal, the pedal push rod 1 directly moves to be in contact with the ball screw II 25, so that the main cylinder push rod 22 is pushed to move rightwards, brake pressure is built, brake torque is generated at the brake cylinder, and a second safety backup brake process is completed.
Fig. 5 is a schematic diagram showing the position of the pedal push rod 1 pushing the ball screw ii 25 to move during the second safety backup braking process.
Finally, the above embodiments are only intended to illustrate the technical solutions of the present invention and not to limit the present invention, and although the present invention has been described in detail with reference to the preferred embodiments, it will be understood by those skilled in the art that modifications or equivalent substitutions may be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions, and all of them should be covered by the claims of the present invention.
Claims (6)
1. A full decoupling type electron/hydraulic pressure helping hand system for electric automobile regenerative braking, its characterized in that:
the device comprises a pedal push rod, a simulation cavity end cover, a simulation cavity shell, a main shell, a motor, a pinion, a bearing, a first check valve, a two-position three-way valve I, a liquid storage tank, an energy accumulator reversing valve, a two-position three-way valve II, a two-position three-way valve III, a second check valve, a third check valve, a second loop reversing valve, a first loop reversing valve, a brake main cylinder, a main cylinder end cover, a main cylinder push rod, a large gear, a ball screw I, a ball screw II, a small hydraulic cylinder push rod, a second simulation spring, a recovery cavity shell and a first simulation spring;
one end of the simulation cavity push rod is inserted into the pedal push rod and is fixedly connected with the pedal push rod, and the other end of the simulation cavity push rod is inserted into the simulation cavity shell;
the simulation cavity end cover is fixedly arranged on one side of the simulation cavity shell inserted into the simulation cavity push rod; the first simulation spring is arranged between the simulation cavity push rod and the simulation cavity shell, and the diameter of the end face, facing the first simulation spring, of the simulation cavity push rod is larger than the inner diameter of the first simulation spring;
the simulation cavity shell is fixedly connected with a push rod of the small hydraulic cylinder; the second simulation spring is coaxial with the push rod of the small hydraulic cylinder and is arranged between the simulation cavity shell and the small hydraulic cylinder; the small hydraulic cylinder is fixedly connected with the recovery cavity shell; the end surface of the recovery cavity shell is fixedly connected with the main shell;
the ball screw II is matched with the ball screw I for installation; the ball screw I is arranged on the main shell through a bearing; the bull gear is coaxially arranged on the ball screw I; the small gear is arranged on the main shell through a bearing and is meshed with the large gear; the motor is arranged on the main shell, and an output shaft of the motor is coaxially connected with the pinion; the left end of the main cylinder push rod is fixedly connected with a ball screw II; the brake master cylinder is fixedly arranged on the main shell through a master cylinder end cover;
the liquid storage tank is arranged on the brake master cylinder and is connected with the two oil inlets of the brake master cylinder; the oil inlet hole of the small hydraulic cylinder is connected to the liquid storage tank through a hydraulic pipeline; the oil outlet of the small hydraulic cylinder is sequentially connected to the first check valve and the two-position three-way valve I through hydraulic pipelines; two outlets of the two-position three-way valve I are respectively connected to the energy accumulator and the two-position three-way valve II; one outlet of the two-position three-way valve II is connected with the front brake circuit and the rear brake circuit, and the other outlet of the two-position three-way valve II is connected to the liquid storage tank;
a branch outlet of the accumulator is connected to an accumulator reversing valve; the energy accumulator reversing valve is connected to a two-position three-way valve III; one outlet of the two-position three-way valve III is respectively connected to the front brake circuit and the rear brake circuit through a second check valve and a third check valve, and the other outlet of the two-position three-way valve III is connected to the liquid storage tank; two oil outlets of the brake master cylinder are respectively connected to the front brake circuit and the rear brake circuit through a first circuit reversing valve and a second circuit reversing valve.
2. The fully decoupled electric/hydraulic assist system for regenerative braking of an electric vehicle as claimed in claim 1, wherein: the simulation chamber push rod is provided with an extension section towards one end of the first simulation spring, the outer diameter of the extension section is smaller than the inner diameter of the first simulation spring, and the extension section extends into the first simulation spring and is used for limiting when the simulation chamber push rod moves.
3. The fully decoupled electric/hydraulic assist system for regenerative braking of an electric vehicle as claimed in claim 1, wherein: the first simulation spring is a linear cylindrical spiral spring, the rigidity is unchanged, the second simulation spring is a nonlinear conical spiral spring, the rigidity is variable, the minimum value of the rigidity of the second simulation spring is equal to the rigidity value of the first simulation spring, and the maximum value of the rigidity of the second simulation spring is larger than the rigidity value of the first simulation spring.
4. The fully decoupled electric/hydraulic assist system for regenerative braking of an electric vehicle as claimed in claim 1, wherein: the distance between the simulation cavity push rod and the contact surface of the first simulation spring and the bottom surface of the simulation cavity shell is shorter than the natural length of the first simulation spring.
5. The fully decoupled electric/hydraulic assist system for regenerative braking of an electric vehicle as claimed in claim 1, wherein: the two sides of the pedal push rod are provided with branched structures, the two sides of the recovery cavity shell are provided with grooves, the sizes of the grooves in the two sides of the recovery cavity shell are larger than those of the branched structures in the two sides of the pedal push rod, and the branched structures in the two sides of the pedal push rod are guaranteed to move in the grooves in the two sides of the recovery cavity shell.
6. The fully decoupled electric/hydraulic assist system for regenerative braking of an electric vehicle as claimed in claim 1, wherein: the energy of the driver stepping on the brake pedal is converted into the pressure energy of the brake oil through the small hydraulic cylinder and stored in the energy accumulator.
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CN113085810B (en) * | 2021-05-11 | 2022-07-22 | 重庆大学 | Pedal force sense simulation device based on magneto-rheological |
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CN103754203B (en) * | 2014-01-08 | 2016-05-18 | 同济大学 | A kind of EHB with mechanical type fail safe |
CN107200001A (en) * | 2017-06-05 | 2017-09-26 | 重庆大学 | HEV/EV regenerative braking control pressurer systems based on front and back wheel bi-motor |
KR20190047460A (en) * | 2017-10-27 | 2019-05-08 | 주식회사 만도 | Electric brake system |
CN108189826B (en) * | 2018-02-06 | 2023-10-27 | 吉林大学 | Full decoupling type mechanical and electronic power-assisted braking system suitable for braking energy recovery |
CN109177946B (en) * | 2018-11-02 | 2019-05-31 | 吉林大学 | A kind of full decoupled formula integrated electronic brake fluid system of reactionless disk |
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