Hydraulic brake device and zero-drag torque control method

Abstract

The application discloses a hydraulic brake device, comprising a liquid pot, a motor master cylinder adjusting valve, a motor master cylinder, a motor master cylinder isolation valve and a wheel cylinder; wherein the liquid pot is used for storing brake fluid; the motor master cylinder adjusting valve is connected between the liquid pot and the motor master cylinder, and the motor master cylinder isolation valve is connected between the motor master cylinder and the wheel cylinder; when the ABS anti-lock function is triggered, the motor master cylinder isolation valve is closed first, the motor master cylinder adjusting valve is opened, the motor master cylinder sucks in brake fluid from the liquid pot, then the motor master cylinder adjusting valve is closed first, the motor master cylinder isolation valve is opened, and the motor master cylinder supplements the brake fluid sucked from the liquid pot into the wheel cylinder, so that the brake fluid is quickly supplemented into the wheel cylinder, and thus enough brake fluid in the wheel cylinder can be ensured, the wheel end braking force is sufficient, and a better braking effect is achieved. The application further provides a zero-drag torque control method, which can improve the fuel economy and the cruising range of the automobile, and is especially suitable for new energy vehicles.

Description

Technical Field

[0001] This application relates to the field of vehicle hydraulic braking technology, specifically to a hydraulic braking device and a zero-drag torque control method. Background Technology

[0002] Existing automotive hydraulic braking systems suffer from the following problems: First, insufficient brake fluid in the master cylinder is a common issue when the ABS anti-lock braking system is operating. This occurs because when the ABS detects wheel lock-up (i.e., the wheel cannot turn due to excessive braking force), it repeatedly energizes the pressure relief valve, opening it from a closed state to an open state. This relieves pressure in the wheel cylinder, allowing the wheel to turn. After the pressure relief valve opens, the brake fluid in the reservoir is at normal pressure, so the high-pressure brake fluid in the wheel cylinder flows into the reservoir through the piping. During this process, to ensure sufficient braking force at the wheel end (i.e., enough brake fluid in the wheel cylinder), the piston in the master cylinder needs to continuously advance to compensate for the brake fluid lost due to the pressure relief valve opening and flowing back into the reservoir. However, this forward movement of the master cylinder piston cannot be sustained indefinitely, as it will inevitably collide with the end of the master cylinder. Therefore, other control methods are urgently needed to ensure sufficient brake fluid in the master cylinder.

[0003] Secondly, excessive drag torque in a car's braking system can reduce fuel economy and increase fuel and electricity consumption. Drag torque refers to the residual friction between the brake pads and brake discs after the driver releases the brake pedal, caused by the return force of the brake caliper piston. This means that even when the wheel cylinder pressure is 0 MPa, the brake pads and discs cannot completely disengage; in other words, there is always residual friction between them, and they remain in a "sticky" state. Summary of the Invention

[0004] The present invention aims to at least solve one of the technical problems existing in the prior art. Therefore, one object of the present invention is to provide a hydraulic braking device and a zero-drag torque control method.

[0005] The first aspect of the present invention provides a hydraulic braking device.

[0006] According to a first aspect of the present invention, a hydraulic braking device includes: a reservoir, a master cylinder regulating valve, a master cylinder, a master cylinder isolation valve, and wheel cylinders; wherein, the reservoir is used to store brake fluid; the master cylinder regulating valve is connected between the reservoir and the master cylinder, and the master cylinder isolation valve is connected between the master cylinder and the wheel cylinders;

[0007] When the ABS anti-lock braking function is triggered, the motor master cylinder isolation valve closes first, the motor master cylinder regulating valve opens, and the motor master cylinder draws brake fluid from the reservoir. Subsequently, the motor master cylinder regulating valve closes first, the motor master cylinder builds pressure, the motor master cylinder isolation valve opens, and the motor master cylinder replenishes the brake fluid drawn from the reservoir into the wheel cylinder.

[0008] According to the first aspect of the present invention, a hydraulic braking device is provided by adding a motor master cylinder regulating valve to the pipeline between the hydraulic reservoir and the motor master cylinder of the original hydraulic braking device. When the ABS anti-lock braking function is triggered, the motor master cylinder isolation valve is closed first, and the motor master cylinder regulating valve is opened. The motor master cylinder quickly draws brake fluid from the reservoir. Subsequently, the motor master cylinder regulating valve is closed first, the motor master cylinder builds pressure, the motor master cylinder isolation valve is opened, and the motor master cylinder quickly replenishes the brake fluid drawn from the reservoir into the wheel cylinder. This achieves rapid replenishment of brake fluid into the wheel cylinder, thereby ensuring that there is still enough brake fluid in the wheel cylinder, ensuring sufficient braking force at the wheel end, and achieving a better braking effect.

[0009] In some embodiments, the motor main cylinder regulating valve is a pilot-operated two-stage normally closed valve.

[0010] In some embodiments, the motor master cylinder includes a cylinder body, a piston, and a motor; the piston is disposed in the cylinder body, and the motor controls the movement of the piston;

[0011] When the ABS anti-lock braking function is triggered, the master cylinder isolation valve closes first, the master cylinder regulating valve opens, and the motor controls the piston to move from a first specific position to a second specific position within the cylinder, so that the master cylinder draws brake fluid from the reservoir. Subsequently, the master cylinder regulating valve closes first, and the motor controls the piston to move from the second specific position to the first specific position. During the piston's movement from the second specific position to the first specific position, if the pressure within the cylinder is less than a specific value compared to the pressure between the master cylinder isolation valve and the mechanical master cylinder isolation valve, the master cylinder isolation valve opens, and the master cylinder replenishes the wheel cylinder with the brake fluid drawn from the reservoir.

[0012] In some embodiments, the liquid reservoir is connected to the inlet of the motor main cylinder regulating valve via a first pipeline, the outlet of the motor main cylinder regulating valve is connected to the inlet of the cylinder via a second pipeline, and the outlet of the cylinder is connected to the motor main cylinder isolation valve via a third pipeline. Both the inlet and outlet of the cylinder are located at one end of the cylinder.

[0013] In some embodiments, both the first specific position and the second specific position are located on one side of the liquid inlet of the cylinder, and the first specific position is located between the liquid inlet of the cylinder and the second specific position.

[0014] In some embodiments, a one-way valve is further included, which is connected in parallel with the motor master cylinder regulating valve between the liquid reservoir and the cylinder body, wherein the one-way valve allows conduction in the direction from the motor master cylinder to the liquid reservoir, and blocks conduction in the opposite direction.

[0015] In some embodiments, the one-way valve is connected to the cylinder body via a fifth pipeline, and the connection between the fifth pipeline and the cylinder body is defined as the compensation hole of the cylinder body.

[0016] In some embodiments, the distance between the compensation hole at the piston mechanical limit position and the piston mechanical limit position of the cylinder is equal to the sum of the volumes of all the wheel cylinders from the drag position to the absolute zero position divided by the cross-sectional area of ​​the piston.

[0017] In some embodiments, the liquid inlet of the cylinder, the first specific position, the second specific position, the compensation hole, and the piston mechanical limit position are sequentially distributed.

[0018] The second aspect of this invention proposes a zero-drag torque control method for a hydraulic braking device.

[0019] The zero-drag torque control method for a hydraulic braking device according to a second aspect embodiment of the present invention is implemented using the hydraulic braking device described in the first aspect embodiment of the present invention; the hydraulic braking device includes:

[0020] The system includes a brake fluid reservoir, a master cylinder regulating valve, a master cylinder, a master cylinder isolation valve, and wheel cylinders; wherein the brake fluid reservoir is used to store brake fluid; the master cylinder regulating valve is connected between the brake fluid reservoir and the master cylinder, and the master cylinder isolation valve is connected between the master cylinder and the wheel cylinders;

[0021] The motor master cylinder includes a cylinder body, a piston, and a motor; the piston is disposed in the cylinder body, and the motor controls the movement of the piston;

[0022] When the ABS anti-lock braking function is triggered, the master cylinder isolation valve closes first, the master cylinder regulating valve opens, and the motor controls the piston to move from a first specific position to a second specific position within the cylinder, so that the master cylinder draws brake fluid from the reservoir. Subsequently, the master cylinder regulating valve closes first, and the motor controls the piston to move from the second specific position to the first specific position. During the piston's movement from the second specific position to the first specific position, if the pressure within the cylinder is less than a specific value compared to the pressure between the master cylinder isolation valve and the mechanical master cylinder isolation valve, the master cylinder isolation valve opens, and the master cylinder replenishes the wheel cylinder with the brake fluid drawn from the reservoir.

[0023] The liquid container is connected to the inlet of the motor main cylinder regulating valve through a first pipe, the outlet of the motor main cylinder regulating valve is connected to the inlet of the cylinder through a second pipe, and the outlet of the cylinder is connected to the motor main cylinder isolation valve through a third pipe. The inlet and outlet of the cylinder are both located at one end of the cylinder.

[0024] Both the first specific position and the second specific position are located on one side of the liquid inlet of the cylinder, and the first specific position is located between the liquid inlet of the cylinder and the second specific position;

[0025] It also includes a one-way valve, which is connected in parallel with the motor master cylinder regulating valve between the liquid tank and the cylinder body. The one-way valve allows conduction in the direction from the motor master cylinder to the liquid tank, and blocks it in the opposite direction.

[0026] The one-way valve is connected to the cylinder body through a fifth pipeline, and the connection between the fifth pipeline and the cylinder body is defined as the compensation hole of the cylinder body;

[0027] The distance between the compensation hole and the piston mechanical limit position of the cylinder is equal to the sum of the volumes of all the wheel cylinders from the drag position to the absolute zero position divided by the cross-sectional area of ​​the piston;

[0028] When the brake is released, it is only necessary to control the motor to drive the piston back to the compensation hole, and then continue to actively retract the piston to the mechanical limit position. At this time, a negative pressure is formed in the cylinder. For the wheel cylinder, under the pressure difference between the external atmospheric pressure and the internal negative pressure, the wheel end friction plate is pulled away from the brake disc, thereby eliminating the drag torque of the brake.

[0029] The zero-drag torque control method for the hydraulic braking device according to the second aspect of the present invention improves the fuel economy and driving range of automobiles, and is particularly suitable for improving the driving range of new energy vehicles.

[0030] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0031] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0032] Figure 1 This is a schematic diagram of the external appearance of the hydraulic braking device of the present invention;

[0033] Figure 2 This is a schematic diagram of the hydraulic braking device of the present invention;

[0034] Figure 3 This is a partial schematic diagram of the hydraulic braking device of the present invention;

[0035] Figure 4 This is a schematic diagram of the structure of a motor master cylinder regulating valve in the hydraulic braking device of the present invention.

[0036] Figure label:

[0037] Hydraulic braking device 1000; liquid reservoir 1; motor main cylinder regulating valve 2; magnetic shielding tube 201; stationary iron 202; moving iron 203; return spring 204; end cap 205; large valve seat 206; small valve seat 207; motor main cylinder 3; cylinder body 301; first specific position 3011; second specific position 3012; compensation hole 3013; piston mechanical limit position 3014; piston 302; motor 303; motor main cylinder isolation valve 4; wheel cylinder 5; first pipeline 6; second pipeline 7; third pipeline 8; one-way valve 9; fifth pipeline 10; pressure reducing valve 11; mechanical main cylinder isolation valve 12. Detailed Implementation

[0038] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0039] The following is combined with Figures 1 to 4 This invention describes the hydraulic braking device 1000 and the zero drag torque control method according to embodiments of the present invention.

[0040] like Figures 1 to 4 As shown, the first aspect of the present invention provides a hydraulic braking device 1000.

[0041] Figure 2The principle of the hydraulic braking device 1000 according to the first aspect embodiment of the present invention is illustrated, wherein the names and categories of each solenoid valve are as follows: TSV: detection valve, normally open valve; SSV: foot-sensing isolation valve, normally closed valve; CSV: mechanical master cylinder isolation valve 12, normally open valve; PSV: motor master cylinder isolation valve 4, normally closed valve; PRV: motor master cylinder regulating valve 2, normally closed valve; IV: pressure boosting valve, normally open valve; OV: pressure reducing valve 11, normally closed valve.

[0042] like Figure 2 As shown, a hydraulic braking device 1000 according to a first aspect embodiment of the present invention includes: a reservoir 1, a master cylinder regulating valve 2, a master cylinder 3, a master cylinder isolation valve 4, and a wheel cylinder 5; wherein, the reservoir 1 is used to store brake fluid; the master cylinder regulating valve 2 is connected between the reservoir 1 and the master cylinder 3, and the master cylinder isolation valve 4 is connected between the master cylinder 3 and the wheel cylinder 5; when the ABS anti-lock braking function is triggered, the master cylinder isolation valve 4 first closes, the master cylinder regulating valve 2 opens, and the master cylinder 3 draws brake fluid from the reservoir 1; subsequently, the master cylinder regulating valve 2 first closes, the master cylinder 3 builds pressure, the master cylinder isolation valve 4 opens, and the master cylinder 3 replenishes the brake fluid drawn from the reservoir 1 into the wheel cylinder 5.

[0043] It is understood that the hydraulic braking device 1000 of the first aspect of the present invention is an improvement on the original hydraulic braking device, that is, a motor master cylinder regulating valve 2 is added to the pipeline between the fluid reservoir 1 and the motor master cylinder 3. The motor master cylinder regulating valve 2 is controlled by the ECU (electronic controller), and its main function is to quickly draw oil and replenish fluid to the motor master cylinder 3 after the ABS anti-lock braking function is triggered. During normal braking, it is in a normally closed state without power. If it is necessary to open the valve core of the motor master cylinder regulating valve 2, it is only necessary to control the motor master cylinder regulating valve 2 by energizing it. Since the motor master cylinder 3 requires a large amount of fluid and a short time during rapid replenishment, usually around 100ms, the motor master cylinder regulating valve 2 must have the characteristics of large flow rate and fast response. It should be noted that the ECU not only controls the master cylinder regulating valve 2, but also other components of the hydraulic braking device 1000, such as various solenoid valves, pressure sensors, brake master cylinder, pedal feel simulator, etc. After the driver releases the brake pedal, the ECU issues a command to build pressure in the master cylinder 3. By controlling different solenoid valves to open or close, pressure is built into the wheel cylinders 5 of the vehicle for braking.

[0044] The working principle of the rapid fluid replenishment of the hydraulic braking device 1000 according to the first aspect of the present invention is as follows: Figure 2As shown, when the ABS anti-lock braking function is triggered, the pressure reducing valve 11 of the hydraulic braking device 1000 opens. Since the brake fluid in reservoir 1 is at normal pressure, the high-pressure brake fluid in wheel cylinder 5 flows into reservoir 1. At this time, in order to ensure sufficient braking force at the wheel end, it is necessary to ensure that there is still enough brake fluid in wheel cylinder 5. Therefore, the motor master cylinder isolation valve 4 is closed first, the motor master cylinder regulating valve 2 is opened, and the motor master cylinder 3 quickly draws brake fluid from reservoir 1. Subsequently, the motor master cylinder regulating valve 2 is closed first, the motor master cylinder 3 builds pressure, the motor master cylinder isolation valve 4 is opened, and the motor master cylinder 3 quickly replenishes the brake fluid drawn from reservoir 1 into wheel cylinder 5, thereby ensuring that there is still enough brake fluid in wheel cylinder 5, ensuring sufficient braking force at the wheel end, and achieving a better braking effect.

[0045] In summary, according to the hydraulic braking device 1000 of the first aspect of the present invention, a motor master cylinder regulating valve 2 is added to the pipeline between the hydraulic reservoir 1 and the motor master cylinder 3 of the original hydraulic braking device. When the ABS anti-lock braking function is triggered, the motor master cylinder isolation valve 4 is closed first, and the motor master cylinder regulating valve 2 is opened. The motor master cylinder 3 quickly draws brake fluid from the hydraulic reservoir 1. Subsequently, the motor master cylinder regulating valve 2 is closed first, the motor master cylinder 3 builds pressure, the motor master cylinder isolation valve 4 is opened, and the motor master cylinder 3 quickly replenishes the brake fluid drawn from the hydraulic reservoir 1 into the wheel cylinder 5, thereby realizing the rapid replenishment of brake fluid into the wheel cylinder 5. This ensures that there is still enough brake fluid in the wheel cylinder 5, ensuring sufficient braking force at the wheel end and achieving a better braking effect.

[0046] In some embodiments, the motor master cylinder regulating valve 2 is a pilot-operated two-stage normally closed valve. Pilot-operated two-stage normally closed valves are characterized by large liquid volume and rapid response.

[0047] Specifically, such as Figure 4 As shown, the pilot-operated two-stage normally closed valve includes a magnetic shielding tube 201, a fixed iron 202, a moving iron 203, a return spring 204 connecting the fixed iron 202 and the moving iron 203, a valve core, and an end cap 205. The valve core consists of a large valve seat 206 and a small valve seat 207. After the small valve seat 207 opens (i.e., after the electromagnetic coil surrounding the small valve seat 207 is energized), it reliably pulls open the large valve seat 206, thereby supporting the flow of a large flow of brake fluid. Because the small valve seat 207 is controlled by the electromagnetic coil, it has a rapid response capability, with a time from energization to full opening of approximately 10ms.

[0048] In some embodiments, such as Figure 2 and Figure 3 As shown, the motor master cylinder 3 includes a cylinder body 301, a piston 302 and a motor 303; the piston 302 is disposed in the cylinder body 301, and the motor 303 controls the movement of the piston 302;

[0049] When the ABS anti-lock braking function is triggered, the master cylinder isolation valve 4 closes first, the master cylinder regulating valve 2 opens, and the motor 303 controls the piston 302 to move from the first specific position 3011 to the second specific position 3012 in the cylinder 301, so that the master cylinder 3 draws brake fluid from the reservoir 1. Subsequently, the master cylinder regulating valve 2 closes first, and the motor 303 controls the piston 302 to move from the second specific position 3012 to the first specific position 3011. During the process of the piston 302 moving from the second specific position 3012 to the first specific position 3011, when the pressure in the cylinder 301 is less than a specific value than the pressure between the master cylinder isolation valve 4 and the mechanical master cylinder isolation valve 12, the master cylinder isolation valve 4 opens, and the master cylinder 3 replenishes the brake fluid drawn from the reservoir 1 into the wheel cylinder 5. The distance between the first specific position 3011 and the second specific position 3012 is determined based on the amount of liquid replenishment required by the master cylinder motor 303. For example, the distance between the first specific position 3011 and the second specific position 3012 can be 20mm. The specific value needs to be sufficient to maintain the pressure of the master cylinder 3 before and after liquid replenishment, and can preferably be 2 bar.

[0050] In some embodiments, the liquid reservoir 1 is connected to the inlet of the motor main cylinder regulating valve 2 via the first pipe 6, the outlet of the motor main cylinder regulating valve 2 is connected to the inlet of the cylinder body 301 via the second pipe 7, and the outlet of the cylinder body 301 is connected to the motor main cylinder isolation valve 4 via the third pipe 8. The inlet and outlet of the cylinder body 301 are both located at one end of the cylinder body 301, and the positions of the inlet and outlet of the cylinder body 301 are reasonably set.

[0051] In some embodiments, the first specific position 3011 and the second specific position 3012 are both located on one side of the liquid inlet of the cylinder 301, and the first specific position 3011 is located between the liquid inlet of the cylinder 301 and the second specific position 3012.

[0052] In some embodiments, a one-way valve 9 is also included. The one-way valve 9 is connected in parallel with the motor master cylinder regulating valve 2 between the reservoir 1 and the cylinder body 301. The one-way valve 9 allows conduction in the direction from the motor master cylinder 3 to the reservoir 1, and blocks it from the opposite direction. It can be understood that the hydraulic braking device 1000 of this embodiment is based on the addition of the motor master cylinder regulating valve 2 to the pipeline between the reservoir 1 and the motor master cylinder 3 of the original hydraulic braking device 1000, and then the addition of the one-way valve 9. The added one-way valve 9 is connected in parallel with the motor master cylinder regulating valve 2 between the reservoir 1 and the cylinder body 301, and the one-way valve 9 allows conduction in the direction from the motor master cylinder 3 to the reservoir 1. By setting the one-way valve 9, the pipeline of the hydraulic braking device 1000 can be kept at constant pressure when the piston 302 returns to the piston mechanical limit position 3014.

[0053] In some embodiments, the one-way valve 9 is connected to the cylinder body 301 via the fifth pipe 10, and the connection between the fifth pipe 10 and the cylinder body 301 is defined as the compensation hole 3013 of the cylinder body 301.

[0054] In some embodiments, the distance between the compensation hole 3013 and the piston mechanical limit position 3014 of the cylinder body 301 is equal to the sum of the volumes of all wheel cylinders 5 from the drag position to the absolute zero position divided by the cross-sectional area of ​​the piston 302. Thus, when the brake is released, it is only necessary to control the motor 303 to drive the piston 302 back to the compensation hole 3013, and then continue to actively retract the piston 302 to the piston mechanical limit position 3014. At this time, a negative pressure is formed inside the cylinder body 301. For the wheel cylinders 5, under the pressure difference between the external atmospheric pressure and the internal negative pressure, the wheel end friction pads are pulled away from the brake disc, thereby eliminating the drag torque of the brake, improving the fuel economy and driving range of the vehicle, and is especially suitable for improving the driving range of new energy vehicles.

[0055] In some embodiments, the liquid inlet of the cylinder 301, the first specific position 3011, the second specific position 3012, the compensation hole 3013, and the mechanical limit position of the piston 302 are arranged in a sequential and reasonable manner. The distance from the liquid inlet of the cylinder 301 to the compensation hole 3013 is approximately 57 mm, and the distance from the compensation hole 3013 to the piston mechanical limit position 3014 is approximately 11 mm.

[0056] The second aspect of the present invention also proposes a zero-drag torque control method for a hydraulic braking device 1000.

[0057] The zero-drag torque control method of the hydraulic braking device 1000 according to a second aspect embodiment of the present invention is implemented using the hydraulic braking device 1000 of the first aspect embodiment of the present invention; wherein, the hydraulic braking device 1000 includes: a fluid reservoir 1, a motor master cylinder regulating valve 2, a motor master cylinder 3, a motor master cylinder isolation valve 4, a wheel cylinder 5, and a one-way valve 9. The fluid reservoir 1 is used to store brake fluid; the motor master cylinder regulating valve 2 is connected between the fluid reservoir 1 and the motor master cylinder 3, and the motor master cylinder isolation valve 4 is connected between the motor master cylinder 3 and the wheel cylinder 5. The motor master cylinder 3 includes a cylinder body 301, a piston 302, and a motor 303; the piston 302 is disposed in the cylinder body 301, and the motor 303 controls the movement of the piston 302. Liquid reservoir 1 is connected to the inlet of motor main cylinder regulating valve 2 via first pipe 6. The outlet of motor main cylinder regulating valve 2 is connected to the inlet of cylinder body 301 via second pipe 7. The outlet of cylinder body 301 is connected to motor main cylinder isolation valve 4 via third pipe 8. The inlet and outlet of cylinder body 301 are both located at one end of cylinder body 301. The first specific position 3011 and the second specific position 3012 are both located on one side of the inlet of cylinder body 301, and the first specific position 3011 is located between the inlet and the second specific position 3012. One-way valve 9 is connected in parallel with motor main cylinder regulating valve 2 between liquid tank 1 and cylinder body 301. One-way valve 9 is allowed to conduct in the direction from motor main cylinder 3 to liquid tank 1, and is blocked in the opposite direction. One-way valve 9 is connected to cylinder body 301 through fifth pipe 10. The connection between fifth pipe 10 and cylinder body 301 is defined as compensation hole 3013 of cylinder body 301. Cylinder body 301 has piston mechanical limit position 3014 at one end away from cylinder body 301. The distance between compensation hole 3013 and piston mechanical limit position 3014 is equal to the sum of the volumes of all wheel cylinders 5 from drag position to absolute zero position divided by the cross-sectional area of ​​piston 302.

[0058] When the brake is released, it is only necessary to control the motor 303 to drive the piston 302 back to the compensation hole 3013, and then continue to drive the piston 302 back to the piston mechanical limit position 3014. During the process of actively retracting from the compensation hole 3013 to the piston mechanical limit position 3014, since the motor master cylinder 3 and the liquid reservoir 1 are in a blocked state, a certain negative pressure is formed in the cylinder body 301 when the piston 302 reaches the piston mechanical limit position 3014. For the wheel cylinder 5, under the pressure difference between the external atmospheric pressure and the internal negative pressure, the wheel end friction plate is pulled away from the brake disc.

[0059] The zero-drag torque control method of the hydraulic braking device 1000 according to the second aspect of the present invention can eliminate the drag torque of the brake, improve the fuel economy and driving range of the vehicle, and is especially suitable for improving the driving range of new energy vehicles, without increasing system energy consumption and with low cost.

[0060] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0061] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A hydraulic braking device, characterized in that, include: The system includes a brake fluid reservoir, a master cylinder regulating valve, a master cylinder, a master cylinder isolation valve, and wheel cylinders; wherein the brake fluid reservoir is used to store brake fluid; the master cylinder regulating valve is connected between the brake fluid reservoir and the master cylinder, and the master cylinder isolation valve is connected between the master cylinder and the wheel cylinders; When the ABS anti-lock braking function is triggered, the motor master cylinder isolation valve is closed first, the motor master cylinder regulating valve is opened, and the motor master cylinder draws brake fluid from the reservoir. Subsequently, the motor master cylinder regulating valve is closed first, the motor master cylinder builds pressure, the motor master cylinder isolation valve is opened, and the motor master cylinder replenishes the brake fluid drawn from the reservoir into the wheel cylinder. The master cylinder includes a cylinder body, a piston, and a motor. When the ABS anti-lock braking function is triggered, the master cylinder isolation valve closes first, the master cylinder regulating valve opens, and the motor controls the piston to move from a first specific position to a second specific position within the cylinder body, so that the master cylinder draws brake fluid from the reservoir. Subsequently, the master cylinder regulating valve closes first, and the motor controls the piston to move from the second specific position to the first specific position. During the piston's movement from the second specific position to the first specific position, when the pressure within the cylinder body is less than a specific value compared to the pressure between the master cylinder isolation valve and the mechanical master cylinder isolation valve, the master cylinder isolation valve opens, and the master cylinder replenishes the brake fluid drawn from the reservoir into the wheel cylinder. It also includes a one-way valve, which is connected in parallel with the motor master cylinder regulating valve between the liquid tank and the cylinder body. The one-way valve allows conduction in the direction from the motor master cylinder to the liquid tank, and blocks it in the opposite direction. The one-way valve is connected to the cylinder body through a fifth pipeline, and the connection between the fifth pipeline and the cylinder body is defined as the compensation hole of the cylinder body; The distance between the compensation hole and the piston mechanical limit position of the cylinder is equal to the sum of the volumes of all the wheel cylinders from the drag position to the absolute zero position divided by the cross-sectional area of ​​the piston; The liquid inlet of the cylinder, the first specific position, the second specific position, the compensation hole, and the piston mechanical limit position are distributed in sequence. The hydraulic braking device adopts a zero drag torque control method: when the brake is released, it is only necessary to control the motor to drive the piston back to the compensation hole, and then continue to actively retract the piston to the piston mechanical limit position. At this time, a negative pressure is formed in the cylinder. For the wheel cylinder, under the pressure difference between the external atmospheric pressure and the internal negative pressure, the wheel end friction plate is pulled away from the brake disc, thereby eliminating the drag torque of the brake.

2. The hydraulic braking device according to claim 1, characterized in that, The main cylinder regulating valve of the motor is a pilot-operated two-stage normally closed valve.

3. The hydraulic braking device according to claim 1, characterized in that, The liquid reservoir is connected to the inlet of the motor main cylinder regulating valve via a first pipe. The outlet of the motor main cylinder regulating valve is connected to the inlet of the cylinder via a second pipe. The outlet of the cylinder is connected to the motor main cylinder isolation valve via a third pipe. Both the inlet and outlet of the cylinder are located at one end of the cylinder.

4. The hydraulic braking device according to claim 3, characterized in that, Both the first specific position and the second specific position are located on one side of the liquid inlet of the cylinder, and the first specific position is located between the liquid inlet of the cylinder and the second specific position.

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