Adjustable pedal sensing electro-hydraulic braking system and control method thereof

Abstract

The invention discloses an adjustable pedal sensing electro-hydraulic braking system and a control method thereof, and belongs to the technical field of automobile brake-by-wire chassis, the adjustable pedal sensing electro-hydraulic braking system comprises a main cylinder assembly and a simulator assembly, the main cylinder assembly and the simulator assembly are connected and integrated in a valve block, and the simulator assembly comprises a direct current motor. The direct-current motor is connected with a lead screw pair transmission structure through a motor rotating shaft, the lead screw pair transmission structure is connected with a piston assembly, the piston assembly is located in a first cylinder body, the direct-current motor is connected with an electronic control unit (ECU), and the first cylinder body is communicated with the main cylinder assembly through a first electromagnetic valve. According to the adjustable pedal force electro-hydraulic braking system and the control method thereof, the direct-current motor, the lead screw pair transmission structure and the in-cavity piston are adopted, hydraulic pressure in a cavity can be changed so as to achieve the effect of adjusting and feeding back pedal force, different pedal force feelings are achieved, and various pedal force feeling requirements are met; and the problem that a traditional pure mechanical part is slow in response can be solved.

Description

Technical Field

[0001] The invention relates to the technical field of automobile brake-by-wire chassis, and in particular to an electro-hydraulic brake system with adjustable pedal sensing and a control method thereof. Background Art

[0002] In the existing technology, wire control braking is the development direction of automobile braking systems. As users' requirements for vehicle driving comfort become higher and higher, the attention paid to the brake pedal feel is also increasing.

[0003] The pedal feel is determined by the cooperation between the simulator assembly and the master cylinder assembly. The working principle is that the master cylinder assembly transmits the pedal force to the piston in the master cylinder assembly cavity through the push rod fork and the master cylinder assembly push rod. The movement of the piston in the cavity compresses the brake fluid in the cavity, thereby converting the pedal input force into output hydraulic pressure. The hydraulic pressure output by the master cylinder assembly pushes the simulator piston to move, compressing the simulator spring assembly and finally contacting and compressing the buffer rubber to achieve feedback of the pedal stroke and pedal force.

[0004] With the development of automobile electrification, major OEMs have different requirements for the pedal feel of the brake pedal. For this reason, different simulator component solutions are required for different customers. The mainstream simulator solution in the current market is a spring and disc spring assembly, which is composed of multiple springs or stacked springs. These solutions are essentially mechanical hydraulic simulations, and only one type of pedal simulation solution can correspond to one type of vehicle. If there are multiple customer matches, there must be multiple simulator components, and management is extremely complicated. At the same time, for the mechanical pedal force set by the newly emerging EMB, it has a full mechanical top feel, and the customer experience is extremely poor. At the same time, the simulator components of the traditional solution are purely mechanical structures and respond slowly when working. There is an urgent need for an electro-hydraulic braking solution with a unified mechanical structure that can change the pedal feel by simply changing the software controller instructions. Summary of the invention

[0005] The purpose of the present invention is to provide an electro-hydraulic brake system with adjustable pedal feel and a control method thereof, which adopts a DC motor, a screw sub-transmission structure and an intra-cavity piston. Not only can the DC motor drive the screw sub-transmission structure to drive the intra-cavity piston to move linearly when working, thereby changing the size of the liquid pressure in the cavity to achieve the effect of adjusting the feedback pedal force feel, but it can also solve the problem of slow response of traditional pure mechanical parts.

[0006] To achieve the above-mentioned objectives, the present invention provides an adjustable pedal-sensing electro-hydraulic brake system, comprising a master cylinder assembly and a simulator assembly, wherein the master cylinder assembly and the simulator assembly are connected and integrated in a valve block, wherein the simulator assembly comprises a DC motor, wherein the DC motor is connected to a screw sub-transmission structure via a motor rotating shaft, wherein the screw sub-transmission structure is connected to a piston assembly, wherein the piston assembly is located in a first cylinder body, wherein the DC motor is connected to an ECU electronic control unit, and wherein the first cylinder body and the master cylinder assembly are connected via a first solenoid valve.

[0007] Preferably, the master cylinder assembly includes a second cylinder body, the second cylinder body is connected to the fluid storage pot, a return spring is provided in the second cylinder body, the return spring is connected to the push rod, the push rod is connected to the pedal, and the second cylinder body is connected to the brake wheel cylinder through the solenoid valve assembly.

[0008] Preferably, the second cylinder is connected to a displacement sensor, and the displacement sensor is connected to the ECU electronic control unit.

[0009] Preferably, the solenoid valve assembly includes a second solenoid valve, a third solenoid valve, a fourth solenoid valve, a fifth solenoid valve and a sixth solenoid valve, the second solenoid valve, the third solenoid valve, the fourth solenoid valve, the fifth solenoid valve and the sixth solenoid valve are all normally open solenoid valves, the second cylinder body is connected to the second solenoid valve, and the second solenoid valve is respectively connected to the third solenoid valve, the fourth solenoid valve, the fifth solenoid valve and the sixth solenoid valve.

[0010] Preferably, the master cylinder assembly, the simulator assembly, the high-pressure pressure building unit and the brake wheel cylinder form a hydraulic system, the brake wheel cylinder includes a left front wheel cylinder, a right rear wheel cylinder, a right front wheel cylinder and a left rear wheel cylinder, the third solenoid valve is connected to the left front wheel cylinder, the fourth solenoid valve is connected to the right rear wheel cylinder, the fifth solenoid valve is connected to the right front wheel cylinder, and the sixth solenoid valve is connected to the left rear wheel cylinder.

[0011] Preferably, the high-pressure building unit includes a first high-pressure unit and a second high-pressure unit, the first high-pressure unit is connected between the second solenoid valve and the third solenoid valve, and the second high-pressure unit is connected between the second solenoid valve and the sixth solenoid valve.

[0012] Preferably, the first solenoid valve is a normally closed solenoid valve, the first solenoid valve is connected to the second cylinder body, and the DC motor is installed on the outside of the first cylinder body.

[0013] A control method for an electro-hydraulic brake system with adjustable pedal sense comprises the following steps:

[0014] S1, stepping on the pedal causes the push rod to move linearly in the second cylinder body, and the oil in the second cylinder body enters the four brake wheel cylinders through the second solenoid valve, the third solenoid valve, the fourth solenoid valve, the fifth solenoid valve and the sixth solenoid valve for braking;

[0015] S2, the displacement sensor monitors the distance the push rod moves and then outputs a displacement signal. At this time, the second solenoid valve is closed and the first solenoid valve is opened. The software controls the ECU electronic control unit to drive the DC motor according to the displacement signal, so that the DC motor drives the piston assembly to move linearly in the first cylinder through the screw pair transmission structure to generate high pressure, and the force is fed back to the second cylinder to generate pedal force and feedback to the pedal end;

[0016] S3. After the second solenoid valve is closed, the control unit of the high-pressure pressure building unit controls the output torque of the internal power motor based on the pedal displacement-power torque relationship diagram of the previous calibration data, and outputs the high-pressure pressure through the output unit through the internal transmission mechanism such as planetary gears and screws, and then through the solenoid valve assembly, output to the brake wheel cylinder to achieve service braking.

[0017] Therefore, the present invention adopts the above-mentioned adjustable pedal-sensing electro-hydraulic brake system and its control method, which adopts a DC motor, a screw sub-transmission structure and an intra-cavity piston. Not only can the DC motor drive the screw sub-transmission structure to drive the intra-cavity piston to move linearly when working, thereby changing the size of the liquid pressure in the cavity to achieve the effect of adjusting the feedback pedal force, but it can also solve the problem of slow response of traditional pure mechanical parts.

[0018] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a hydraulic principle diagram of an electro-hydraulic brake system with adjustable pedal sense of the present invention;

[0020] Figure 2 The present invention is a curve diagram of a hydraulic simulation pedal stroke and force value curve of an adjustable pedal-sensing electro-hydraulic brake system embodiment.

[0021] Reference numerals

[0022] 1. Simulator assembly; 111. DC motor; 112. Screw pair transmission structure; 113. Piston assembly; 114. First cylinder body; 115. ECU electronic control unit; 116. First solenoid valve; 2. Master cylinder assembly; 211. Displacement sensor; 212. Second cylinder body; 213. Liquid reservoir; 214. Return spring; 215. Push rod; 216. Pedal; 4. Right front wheel cylinder; 5. Right rear wheel cylinder; 6. Left rear wheel cylinder; 7. Left front wheel cylinder; 11. Second solenoid valve; 12. Third solenoid valve; 13. Fourth solenoid valve; 14. Fifth solenoid valve; 15. Sixth solenoid valve; 16. First high-voltage unit; 17. Second high-voltage unit. DETAILED DESCRIPTION

[0023] The technical solution of the present invention is further described below through the accompanying drawings and embodiments.

[0024] Unless otherwise defined, the technical terms or scientific terms used in the present invention should be understood by people with ordinary skills in the field to which the present invention belongs. The words "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0025] Embodiment 1

[0026] like Figure 1 to Figure 2 As shown, the present invention provides an adjustable pedal-sensing electro-hydraulic brake system, including a master cylinder assembly 2 and a simulator assembly 1, the master cylinder assembly 2 and the simulator assembly 1 are connected and integrated in the valve block, and the simulator assembly 1 and the master cylinder assembly 2 can generate pedal 216 force and provide feedback. The simulator assembly 1 includes a DC motor 111, the DC motor 111 is connected to an ECU electronic control unit 115, the DC motor 111 is connected to a screw pair transmission structure 112 through a motor rotating shaft, the screw pair transmission structure 112 is connected to a piston assembly 113, the DC motor 111 is mounted on the outside of a first cylinder body 114, and the piston assembly 113 is located in the first cylinder body 114. The ECU electronic control unit 115 drives the DC motor 111, so that the DC motor 111 drives the piston assembly 113 to move linearly in the first cylinder body 114 through the screw pair transmission structure 112, thereby realizing a change in liquid pressure.

[0027] The first cylinder body 114 is connected to the master cylinder assembly 2 via the first solenoid valve 116. The oil pressure in the first cylinder body 114 is fed back to the master cylinder assembly 2 via the first solenoid valve 116. The master cylinder assembly 2 generates a pedal 216 force and feeds it back to the pedal 216 end. Different pedal 216 force sensations can be achieved by controlling the output torque of the motor.

[0028] The master cylinder assembly 2 includes a second cylinder body 212, which is connected to a liquid reservoir 213, and oil is stored in the liquid reservoir 213. A return spring 214 is arranged in the second cylinder body 212, and the return spring 214 is connected to a push rod 215, and the push rod 215 is connected to a pedal 216. The oil in the simulator assembly 1 flows into the second cylinder body 212 through the first solenoid valve 116 to realize the oil pressure change in the second cylinder body 212, and the pedal 216 force generated by the oil pressure change is fed back to the pedal 216 end through the push rod 215.

[0029] The second cylinder body 212 is connected to the displacement sensor 211, and the displacement sensor 211 is connected to the ECU electronic control unit 115. The displacement sensor 211 outputs a displacement signal of the pedal 216. Based on the displacement signal of the push rod 215 provided by the displacement sensor 211 at the end of the pedal 216, the ECU drives the DC motor 111 to drive the screw rod to work and drive the piston in the cavity to move linearly to generate high pressure.

[0030] The second cylinder 212 is connected to the brake wheel cylinder through the solenoid valve assembly, and the solenoid valve assembly can switch the pipeline between the second cylinder 212 and the brake wheel cylinder to achieve braking. The solenoid valve assembly includes a second solenoid valve 11, a third solenoid valve 12, a fourth solenoid valve 13, a fifth solenoid valve 14 and a sixth solenoid valve 15. The second solenoid valve 11, the third solenoid valve 12, the fourth solenoid valve 13, the fifth solenoid valve 14 and the sixth solenoid valve 15 are all normally open solenoid valves. The second cylinder 212 is connected to the second solenoid valve 11, and the second solenoid valve 11 is respectively connected to the third solenoid valve 12, the fourth solenoid valve 13, the fifth solenoid valve 14 and the sixth solenoid valve 15.

[0031] The first solenoid valve 116 is a normally closed solenoid valve. The first solenoid valve 116 is connected to the second cylinder 212 . The first solenoid valve 116 can control the on-off of the pipeline between the first cylinder 114 and the second cylinder 212 .

[0032] The master cylinder assembly 2, the simulator assembly 1, the high pressure build-up unit and the brake wheel cylinder form a hydraulic system, and the high pressure build-up unit can generate high braking pressure for the motor-driven gear or screw pair movement. The brake wheel cylinder includes a left front wheel cylinder 7, a right rear wheel cylinder 5, a right front wheel cylinder 4 and a left rear wheel cylinder 6. The third solenoid valve 12 is connected to the left front wheel cylinder 7, the fourth solenoid valve 13 is connected to the right rear wheel cylinder 5, the fifth solenoid valve 14 is connected to the right front wheel cylinder 4, and the sixth solenoid valve 15 is connected to the left rear wheel cylinder 6.

[0033] The high-pressure building unit includes a first high-pressure unit 16 and a second high-pressure unit 17. The first high-pressure unit 16 is connected between the second solenoid valve 11 and the third solenoid valve 12, and the second high-pressure unit 17 is connected between the second solenoid valve 11 and the sixth solenoid valve 15. The first high-pressure unit 16 and the second high-pressure unit 17 respectively correspond to the "H" or "X" type two-way brake circuits of the whole vehicle braking to realize redundant braking.

[0034] Working principle: When the driver steps on the pedal 216, the push rod 215 is pushed to generate brake pressure. When the whole vehicle brakes normally, the brake pressure pushes the master cylinder hydraulic oil into the simulator; through its solenoid valve switching pipeline, based on the push rod 215 displacement signal provided by the displacement sensor 211 at the pedal 216 end, the ECU drives the DC motor 111 to drive the screw rod to drive the linear movement of the piston in the cavity to generate high pressure, and the force is fed back to the master cylinder to generate the pedal 216 force and fed back to the pedal 216 end, so as to provide the pedal 216 force. By controlling the output torque of the motor, different pedal 216 force feelings can be achieved.

[0035] By controlling the motor retraction speed through software, the hysteresis force of the pedal 216 push rod 215 can be set to avoid the push rod 215 returning too fast and causing a "foot-pushing" feeling, thereby providing a better customer experience, compared to traditional hydraulic or mechanical types which only have one hysteresis force.

[0036] When the vehicle brakes abnormally, such as when the high-pressure pressure building unit fails, the dynamic pressure pushes the hydraulic oil of the master cylinder into the wheel cylinder to generate braking pressure. After stepping on the pedal 216, the hydraulic pressure can still reach the four wheel cylinder ends to realize the braking function, realize the redundant backup function, and improve the safety of the system.

[0037] A control method for an electro-hydraulic brake system with adjustable pedal sense comprises the following steps:

[0038] S1, stepping on the pedal 216 causes the push rod 215 to perform linear motion in the second cylinder 212, and the oil in the second cylinder 212 enters the four brake wheel cylinders through the second solenoid valve 11, the third solenoid valve 12, the fourth solenoid valve 13, the fifth solenoid valve 14 and the sixth solenoid valve 15 to perform braking;

[0039] S2, the displacement sensor 211 monitors the distance moved by the push rod 215 and outputs a displacement signal. At this time, the second solenoid valve 11 is closed and the first solenoid valve 116 is opened. The software controls the ECU electronic control unit 115 to drive the DC motor 111 according to the displacement signal, so that the DC motor 111 drives the piston assembly 113 to move linearly in the first cylinder 114 through the screw pair transmission structure 112 to generate high pressure, and the force is fed back to the second cylinder 212 to generate pedal force and feedback to the pedal end;

[0040] S3. After the second solenoid valve 11 is closed, the control unit of the high-pressure pressure building unit controls the output torque of the internal power motor based on the pedal displacement-power torque relationship diagram of the previous calibration data, and outputs the high-pressure pressure through the output unit through the internal transmission mechanism such as planetary gears, screws, etc., and then through the solenoid valve assembly, output to the brake wheel cylinder to achieve service braking.

[0041] Therefore, the present invention adopts the above-mentioned adjustable pedal-sensing electro-hydraulic brake system and its control method, which adopts a DC motor, a screw sub-transmission structure and an intra-cavity piston. Not only can the DC motor drive the screw sub-transmission structure to drive the intra-cavity piston to move linearly when working, thereby changing the size of the liquid pressure in the cavity to achieve the effect of adjusting the feedback pedal force, but it can also solve the problem of slow response of traditional pure mechanical parts.

[0042] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. An electro-hydraulic brake system with adjustable pedal sense, characterized in that: It includes a master cylinder assembly and a simulator assembly, the master cylinder assembly and the simulator assembly are connected and integrated in the valve block, the simulator assembly includes a DC motor, the DC motor is connected to a screw sub-transmission structure through a motor rotating shaft, the screw sub-transmission structure is connected to a piston assembly, the piston assembly is located in a first cylinder body, the DC motor is connected to an ECU electronic control unit, and the first cylinder body and the master cylinder assembly are connected through a first solenoid valve.

2. The electro-hydraulic brake system with adjustable pedal sense according to claim 1, characterized in that: The master cylinder assembly includes a second cylinder body, the second cylinder body is connected to a fluid reservoir, a return spring is arranged in the second cylinder body, the return spring is connected to a push rod, the push rod is connected to a pedal, and the second cylinder body is connected to a brake wheel cylinder via a solenoid valve assembly.

3. The electro-hydraulic brake system with adjustable pedal sense according to claim 2, characterized in that: The second cylinder is connected to a displacement sensor, and the displacement sensor is connected to the ECU electronic control unit.

4. The electro-hydraulic brake system with adjustable pedal sense according to claim 3, characterized in that: The solenoid valve assembly includes a second solenoid valve, a third solenoid valve, a fourth solenoid valve, a fifth solenoid valve and a sixth solenoid valve. The second solenoid valve, the third solenoid valve, the fourth solenoid valve, the fifth solenoid valve and the sixth solenoid valve are all normally open solenoid valves. The second cylinder body is connected to the second solenoid valve, and the second solenoid valve is connected to the third solenoid valve, the fourth solenoid valve, the fifth solenoid valve and the sixth solenoid valve, respectively.

5. The electro-hydraulic brake system with adjustable pedal sense according to claim 4, characterized in that: The master cylinder assembly, the simulator assembly, the high-pressure pressure building unit and the brake wheel cylinder form a hydraulic system, the brake wheel cylinder includes a left front wheel cylinder, a right rear wheel cylinder, a right front wheel cylinder and a left rear wheel cylinder, the third solenoid valve is connected to the left front wheel cylinder, the fourth solenoid valve is connected to the right rear wheel cylinder, the fifth solenoid valve is connected to the right front wheel cylinder, and the sixth solenoid valve is connected to the left rear wheel cylinder.

6. The electro-hydraulic brake system with adjustable pedal sense according to claim 5, characterized in that: The high-pressure building unit includes a first high-pressure unit and a second high-pressure unit. The first high-pressure unit is connected between the second solenoid valve and the third solenoid valve, and the second high-pressure unit is connected between the second solenoid valve and the sixth solenoid valve.

7. The electro-hydraulic brake system with adjustable pedal sense according to claim 6, characterized in that: The first solenoid valve is a normally closed solenoid valve, the first solenoid valve is connected to the second cylinder body, and the DC motor is installed outside the first cylinder body.

8. A control method for an electro-hydraulic brake system with adjustable pedal sensitivity as claimed in claims 1 to 7, characterized in that: The following steps are involved: S1, stepping on the pedal causes the push rod to move linearly in the second cylinder body, and the oil in the second cylinder body enters the four brake wheel cylinders through the second solenoid valve, the third solenoid valve, the fourth solenoid valve, the fifth solenoid valve and the sixth solenoid valve for braking; S2, the displacement sensor monitors the distance the push rod moves and then outputs a displacement signal. At this time, the second solenoid valve is closed and the first solenoid valve is opened. The software controls the ECU electronic control unit to drive the DC motor according to the displacement signal, so that the DC motor drives the piston assembly to move linearly in the first cylinder through the screw pair transmission structure to generate high pressure, and the force is fed back to the second cylinder to generate pedal force and feedback to the pedal end; S3. After the second solenoid valve is closed, the control unit of the high-pressure pressure building unit controls the output torque of the internal power motor based on the pedal displacement-power torque relationship diagram of the previous calibration data, and outputs the high-pressure pressure through the output unit through the internal transmission mechanism such as planetary gears and screws, and then through the solenoid valve assembly, output to the brake wheel cylinder to achieve service braking.

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