Hydraulic braking system and vehicle

Abstract

The invention provides a hydraulic brake system which comprises an oil can, a brake master cylinder, a pedal simulator, an electric supercharging device, a wheel brake unit, a brake pedal, a control unit and a backflow oil way, the two ends of the backflow oil way are connected with the oil can and a hydraulic cavity of the brake master cylinder respectively, and a backflow valve is arranged on the backflow oil way; the control unit is connected with the return valve and used for controlling opening and closing of the return valve according to the braking efficiency of the vehicle braking device during braking. When the backflow valve is opened, brake fluid in the hydraulic cavity of the brake master cylinder can flow back to the oil can through the backflow oil way. The hydraulic brake system can increase the stroke of the brake pedal when the brake efficiency of the vehicle brake device is attenuated, so that a driver can sense the attenuation of the brake efficiency. The invention further provides a vehicle.

Description

Technical Field

[0001] The present invention relates to the technical field of hydraulic brakes, and in particular to a hydraulic brake system and a vehicle. Background Art

[0002] With the gradual popularization of electric vehicles, integrated electric power-assisted braking systems have been widely used in various types of electric vehicles. When the electric power-assisted braking system is working, the hydraulic circuit between the brake master cylinder and the wheel brake is cut off, and the hydraulic pressure of the wheel brake is generated by the electric power. The hydraulic pressure generated by the driver stepping on the brake pedal enters the PFS (Pedal Force Sensor) pedal simulator, thereby providing the driver with a pedal feel under different pedal strokes and different braking intensities; when the electric power-assisted braking system fails, the hydraulic circuit between the brake master cylinder and the wheel brake is connected, and the hydraulic pressure generated by the driver stepping on the brake pedal directly acts on the wheel brake for braking.

[0003] In the scenario of intense vehicle driving, such as on-track mode, rapid acceleration and deceleration, long downhill mountain roads, etc., the repeated braking of the vehicle will cause the temperature of the vehicle's braking system to be too high, which will reduce the braking efficiency of the vehicle's braking system and weaken the braking ability. However, in the electric power-assisted braking mode, the pedal feeling felt by the driver when stepping on the brake pedal comes from the PFS pedal simulator, and the driver cannot perceive the attenuation of the braking efficiency of the braking system like driving a traditional vehicle, making it impossible for the driver to react in advance when the braking efficiency is attenuated, thus affecting driving safety. Summary of the invention

[0004] The object of the present invention is to provide a hydraulic braking system and a vehicle, aiming to solve or at least partially solve the deficiencies of the above-mentioned background technology. The hydraulic braking system can increase the stroke of the brake pedal when the braking efficiency of the vehicle's braking device decays, so that the driver can feel the decay of the braking efficiency.

[0005] The present invention provides a hydraulic braking system, comprising an oil pot, a brake master cylinder, a pedal simulator, an electric booster, a wheel brake unit, a brake pedal and a control unit; the piston rod of the brake master cylinder is connected to the brake pedal, and the hydraulic chamber of the brake master cylinder is respectively connected to the oil pot, the pedal simulator and the wheel brake unit; the electric booster is respectively connected to the oil pot and the wheel brake unit; the hydraulic braking system also includes a reflux oil circuit, the two ends of the reflux oil circuit are respectively connected to the oil pot and the hydraulic chamber of the brake master cylinder, and a reflux valve is provided on the reflux oil circuit; the control unit is connected to the reflux valve, and the control unit is used to control the opening and closing of the reflux valve according to the braking efficiency of the vehicle braking device during braking; when the reflux valve is opened, the brake fluid in the hydraulic chamber of the brake master cylinder can flow back to the oil pot through the reflux oil circuit.

[0006] Furthermore, the return valve is a normally closed valve; when the braking efficiency of the vehicle braking device decays to less than the standard braking efficiency, the control unit controls the return valve to open.

[0007] Further, after the reflux valve is opened for a rated time, the control unit controls the reflux valve to close so as to stop the brake fluid in the hydraulic chamber of the master brake cylinder from flowing back to the oil pot through the reflux oil circuit.

[0008] Furthermore, the brake master cylinder is provided with at least two hydraulic chambers, each of which is respectively connected to the oil pot and the wheel brake unit; and the return oil circuit is connected to one or more of the hydraulic chambers.

[0009] Furthermore, the return oil circuit is connected to one of the hydraulic chambers, and the return oil circuit and the pedal simulator are connected to the same hydraulic chamber.

[0010] Furthermore, the hydraulic chamber of the brake master cylinder is connected to the oil pot through an oil inlet circuit, and the oil inlet circuit and the return circuit are independent of each other; and in the direction from the piston rod of the brake master cylinder to its piston, the connection position of the return circuit and the hydraulic chamber is located downstream of the connection position of the oil inlet circuit and the hydraulic chamber.

[0011] Furthermore, the hydraulic brake system further comprises a vehicle speed sensor, the vehicle speed sensor is used to detect the vehicle speed, and the control unit is connected to the vehicle speed sensor; the control unit is used to calculate the vehicle deceleration according to the vehicle speed detected by the vehicle speed sensor during braking, and calculate the braking efficiency of the vehicle brake device according to the vehicle deceleration;

[0012] And / or, the hydraulic braking system also includes a temperature sensor, which is used to detect the temperature of the vehicle braking device, and the control unit is connected to the temperature sensor; the control unit is used to calculate the braking efficiency of the vehicle braking device based on the temperature detected by the temperature sensor during braking.

[0013] Furthermore, the hydraulic brake system further comprises a mode switching unit, which is connected to the control unit; the control unit has a first working mode and a second working mode, and the mode switching unit is used to control the control unit to switch between the first working mode and the second working mode;

[0014] When the control unit is in the first working mode, the control unit controls the return valve to be always in a closed state; when the control unit is in the second working mode, the control unit controls the opening and closing of the return valve according to the braking efficiency of the vehicle braking device during braking.

[0015] Further, the hydraulic chamber of the brake master cylinder is connected to the pedal simulator through an induction oil circuit, and a simulator control valve is provided on the induction oil circuit; the hydraulic chamber of the brake master cylinder is connected to the wheel brake unit through a first brake oil circuit, and a first brake control valve is provided on the first brake oil circuit; the electric booster device is connected to the wheel brake unit through a second brake oil circuit, and a second brake control valve is provided on the second brake oil circuit;

[0016] The control unit is connected to the simulator control valve, the first brake control valve and the second brake control valve respectively, and is used to control the opening and closing of the simulator control valve, the first brake control valve and the second brake control valve.

[0017] The present invention also provides a vehicle, comprising the hydraulic brake system as described above.

[0018] The hydraulic braking system provided by the present invention is characterized in that a return oil circuit is arranged between an oil pot and a hydraulic chamber of a brake master cylinder, and a return valve is arranged on the return oil circuit; during braking, when the braking efficiency of a vehicle's brake device decays, a control unit controls the return valve to open, so that part of the brake fluid in the hydraulic chamber of the brake master cylinder can flow back to the oil pot through the return oil circuit, and when the driver's pedaling force on the brake pedal is constant, the stroke of the brake pedal becomes longer, that is, the hydraulic braking system can increase the stroke of the brake pedal when the braking efficiency of the vehicle's brake device decays, so that the driver can sense the decay of the braking efficiency of the vehicle's brake device, and then the driver can react in advance when the braking efficiency decays, thereby improving driving safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic diagram of the structure of the hydraulic brake system in an embodiment of the present invention.

[0020] Figure 2 Schematic diagram of control logic of a control unit in an embodiment of the present invention.

[0021] Figure 3 Schematic diagram of control logic of a control unit in another embodiment of the present invention. DETAILED DESCRIPTION

[0022] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0023] The terms "first", "second", "third", "fourth" and the like (if any) in the description and claims of the present invention are used to distinguish similar objects and are not necessarily used to describe a particular sequence or order.

[0024] The directional words such as up, down, left, right, front, back, top, bottom, etc. (if any) involved in the specification and claims of the present invention are defined by the positions of the structures in the drawings and the positions of the structures relative to each other, and are only for the clarity and convenience of expressing the technical solution. It should be understood that the use of directional words should not limit the scope of protection claimed in this application.

[0025] like Figure 1 and Figure 2 As shown, the hydraulic brake system provided by the embodiment of the present invention includes an oil pot 1, a brake master cylinder 2, a pedal simulator 3 (i.e., a PFS pedal simulator), an electric booster 4, a wheel brake unit 5, a brake pedal 6, and a control unit 9. The control unit 9 can be an ECU of the vehicle or an additional controller. The piston rod 21 of the brake master cylinder 2 is connected to the brake pedal 6, and the hydraulic chamber 20 of the brake master cylinder 2 is respectively connected to the oil pot 1, the pedal simulator 3, and the wheel brake unit 5; the electric booster 4 is respectively connected to the oil pot 1 and the wheel brake unit 5.

[0026] The hydraulic brake system also includes a return oil circuit 101, the two ends of which are respectively connected to the oil pot 1 and the hydraulic chamber 20 of the brake master cylinder 2, and a return valve 81 is provided on the return oil circuit 101. The control unit 9 is connected to the return valve 81, and the control unit 9 is used to control the opening and closing of the return valve 81 according to the braking efficiency of the vehicle brake device (not shown; the vehicle brake device can be a disc brake device, a drum brake device, etc.) during braking; when the return valve 81 is opened, the brake fluid in the hydraulic chamber 20 of the brake master cylinder 2 can flow back to the oil pot 1 through the return oil circuit 101.

[0027] Specifically, the higher the braking efficiency of the vehicle's braking device (the braking efficiency can be judged based on the vehicle's braking distance and braking deceleration), the better its braking performance, that is, the greater the vehicle's deceleration when braking; the lower the braking efficiency of the vehicle's braking device, the worse its braking performance, that is, the smaller the vehicle's deceleration when braking.

[0028] When the braking efficiency of the vehicle brake device is greater than or equal to the standard braking efficiency (the standard braking efficiency can be set according to actual needs), the control unit 9 controls the return valve 81 to be in a closed state. At this time, the return oil circuit 101 will not affect the travel of the brake pedal 6.

[0029] When the braking efficiency of the vehicle's braking system is less than the standard braking efficiency, the control unit 9 controls the reflux valve 81 to open, so that part of the brake fluid in the hydraulic chamber 20 of the brake master cylinder 2 flows back to the oil pot 1 through the reflux oil circuit 101. At this time, the hydraulic pressure of the brake fluid in the hydraulic chamber 20 is reduced, and the piston rod 21 of the brake master cylinder 2 needs to move a longer distance to enable the brake fluid in the hydraulic chamber 20 to establish a hydraulic pressure equal to the pedal force, thereby increasing the stroke of the brake pedal 6 (that is, when the driver's pedaling force on the brake pedal 6 is constant, the stroke of the brake pedal 6 becomes longer), so that the driver can sense the attenuation of the braking efficiency of the vehicle's braking system, that is, the hydraulic brake system has a braking efficiency perception function. At the same time, since the pressurization pressure of the brake fluid by the electric booster device 4 is controlled by the stroke of the brake pedal 6, when the braking efficiency of the vehicle's braking device decays and the stroke of the brake pedal 6 becomes longer, the pressurization pressure of the brake fluid by the electric booster device 4 also increases accordingly, that is, the pressure of the brake fluid in the wheel brake unit 5 is increased, thereby improving the braking effect, which just compensates for the influence of the decay of the braking efficiency of the vehicle's braking device on the braking effect (when the braking efficiency of the vehicle's braking device decays, the brake pedal 6 needs a longer pedal stroke and the electric booster device 4 needs to provide a greater pressurization pressure on the brake fluid in order to enable the vehicle's braking device to achieve the same braking force as before the decay; if the reflux oil circuit 101 and the reflux valve 81 are not set, when the driver's pedaling force on the brake pedal 6 is constant, since the stroke of the pedal simulator 3 remains unchanged, the brake pedal 6 cannot achieve a longer pedal stroke at this time).

[0030] Furthermore, in the present embodiment, the reflux valve 81 is a normally closed valve, that is, under normal working conditions, the braking efficiency of the vehicle brake device is greater than or equal to the standard braking efficiency, and the control unit 9 controls the reflux valve 81 to be in a closed state; after working for a long time, the vehicle brake device will cause the braking efficiency to decay due to its temperature increase. When the braking efficiency of the vehicle brake device decays to less than the standard braking efficiency, the control unit 9 controls the reflux valve 81 to open, and after the reflux valve 81 is opened for a rated time (the rated time can be set according to actual needs, for example, 1-2s), the control unit 9 controls the reflux valve 81 to close, so as to stop the brake fluid in the hydraulic chamber 20 of the brake master cylinder 2 from flowing back to the oil pot 1 through the reflux oil circuit 101, that is, the brake fluid in the hydraulic chamber 20 Only a portion of the brake fluid will flow back to the oil tank 1 to prevent the stroke of the brake pedal 6 from increasing significantly due to excessive reflux of the brake fluid in the hydraulic chamber 20, and prevent the pedal simulator 3 from being able to establish sufficient pedal simulation force in time (if the reflux of the brake fluid in the hydraulic chamber 20 is too large, the hydraulic pressure of the brake fluid in the hydraulic chamber 20 will be greatly reduced, and the piston rod 21 of the brake master cylinder 2 will need to move a longer distance before the brake fluid in the hydraulic chamber 20 can establish a hydraulic pressure equal to the pedal force, thereby significantly increasing the stroke of the driver's brake pedal 6, affecting the normal operation of the electric power-assisted braking system; at the same time, the time it takes for the pedal simulator 3 to establish the pedal simulation force will also be lengthened, affecting the user's perception of the pedal force).

[0031] Furthermore, if Figure 2 As shown, in this embodiment, the hydraulic brake system includes a vehicle speed sensor 71, which is used to detect the vehicle speed. The control unit 9 is connected to the vehicle speed sensor 71 (specifically, an electrical signal connection); the control unit 9 is used to calculate the vehicle deceleration according to the vehicle speed detected by the vehicle speed sensor 71 during braking (when braking, the vehicle deceleration can be calculated according to the vehicle speed reduction value and the braking time), and calculate the braking efficiency of the vehicle brake device according to the vehicle deceleration. The vehicle speed sensor 71 can be a wheel speed sensor for detecting the wheel speed, and the vehicle speed is calculated according to the wheel speed.

[0032] Specifically, when the hydraulic braking system provides the same hydraulic braking force to the vehicle's braking device, the smaller the vehicle's deceleration, the lower the braking efficiency of the vehicle's braking device; therefore, a relationship between the vehicle's deceleration and the braking efficiency of the vehicle's braking device can be established in advance (such as a relationship expression, relationship table, relationship curve, etc.). After calculating the vehicle's deceleration, the braking efficiency of the vehicle's braking device can be quickly calculated based on the relationship between the two.

[0033] like Figure 3As shown, in another embodiment, the hydraulic brake system includes a temperature sensor 72, which is used to detect the temperature of the vehicle brake device, and the control unit 9 is connected to the temperature sensor 72; the control unit 9 is used to calculate the braking efficiency of the vehicle brake device according to the temperature detected by the temperature sensor 72 during braking. The temperature sensor 72 can be specifically arranged on a caliper, a friction plate, etc. in the vehicle brake device.

[0034] Specifically, when the hydraulic brake system provides the same hydraulic braking force for the vehicle brake device, the higher the temperature of the vehicle brake device, the lower the braking efficiency of the vehicle brake device; therefore, a relationship between the temperature of the vehicle brake device and the braking efficiency of the vehicle brake device (such as a relationship, a relationship table, a relationship curve, etc.) can be established in advance, and after the temperature of the vehicle brake device is detected, the braking efficiency of the vehicle brake device can be quickly calculated based on the relationship between the two. In other embodiments, the hydraulic brake system can also be provided with a vehicle speed sensor 71 and a temperature sensor 72 at the same time, and the braking efficiency of the vehicle brake device is calculated based on the comprehensive calculation of the two.

[0035] Furthermore, if Figure 1 As shown, in this embodiment, the hydraulic chamber 20 of the brake master cylinder 2 is connected to the pedal simulator 3 through the induction oil circuit 103, and the induction oil circuit 103 is provided with a simulator control valve 82; the hydraulic chamber 20 of the brake master cylinder 2 is connected to the wheel brake unit 5 through the first brake oil circuit 105, and the first brake control valve 83 is provided on the first brake oil circuit 105; the input end of the electric booster 4 is connected to the oil pot 1 through the oil delivery oil circuit 104, and the output end of the electric booster 4 is connected to the wheel brake unit 5 through the second brake oil circuit 106, and the second brake control valve 84 is provided on the second brake oil circuit 106. The control unit 9 is respectively connected to the simulator control valve 82, the first brake control valve 83 and the second brake control valve 84, and the control unit 9 is used to control the opening and closing of the simulator control valve 82, the first brake control valve 83 and the second brake control valve 84.

[0036] Specifically, in this embodiment, the control unit 9 is an electronic control unit, the return valve 81, the simulator control valve 82, the first brake control valve 83 and the second brake control valve 84 are all solenoid valves, and the control unit 9 is electrically signal-connected to the return valve 81, the simulator control valve 82, the first brake control valve 83 and the second brake control valve 84 respectively.

[0037] Furthermore, if Figure 1As shown, in this embodiment, the master cylinder 2 is provided with at least two hydraulic chambers 20, each of which is connected to the oil pot 1 and the wheel brake unit 5, respectively. Since, under the condition that the braking performance of the vehicle brake device is attenuated, the brake fluid in one of the hydraulic chambers 20 only needs to be returned to the oil pot 1 through the return oil circuit 101 to achieve the lengthening of the stroke of the brake pedal 6, the return oil circuit 101 only needs to be connected to one of the hydraulic chambers 20 to simplify the structure and save component costs (no need to make too many changes on the basis of the original oil circuit). Of course, in other embodiments, the return oil circuit 101 can also be connected to multiple hydraulic chambers 20 at the same time (for example, the return oil circuit 101 is connected to all hydraulic chambers 20 at the same time). Under the condition that the braking performance of the vehicle brake device is attenuated, the brake fluid in multiple hydraulic chambers 20 simultaneously returns to the oil pot 1 through the return oil circuit 101.

[0038] Furthermore, if Figure 1 As shown, in the present embodiment, the return oil circuit 101 and the pedal simulator 3 are connected to the same hydraulic chamber 20 (that is, the return oil circuit 101 and the sensing oil circuit 103 are connected to the same hydraulic chamber 20), so that the pedal simulator 3 can establish the pedal simulation force more accurately and quickly (although the hydraulic pressure of the brake fluid in each hydraulic chamber 20 will eventually reach equilibrium, the balancing process requires a certain amount of time; if the return oil circuit 101 and the pedal simulator 3 are respectively connected to different hydraulic chambers 20, then the pedal simulator 3 will have a certain lag in establishing the pedal simulation force).

[0039] Furthermore, if Figure 1 As shown, in this embodiment, the hydraulic chamber 20 of the brake master cylinder 2 is connected to the oil pot 1 through the oil inlet oil circuit 102, and the oil inlet oil circuit 102 and the return oil circuit 101 are independent oil circuits; and in the direction from the piston rod 21 to the piston 22 of the brake master cylinder 2 (in Figure 1 In the middle, that is, from right to left direction), the connection position A between the return oil circuit 101 and the hydraulic chamber 20 is located downstream of the connection position B between the oil inlet circuit 102 (the oil inlet circuit 102 refers to the oil inlet circuit 102 connected to the same hydraulic chamber 20 as the return oil circuit 101) and the hydraulic chamber 20. With such arrangement, when the driver steps on the brake pedal 6, the brake pedal 6 drives the piston rod 21 to push the piston 22 to move, so that the oil inlet circuit 102 is disconnected from the hydraulic chamber 20 (i.e., the piston 22 blocks the connection position B between the oil inlet circuit 102 and the hydraulic chamber 20, and the hydraulic oil in the hydraulic chamber 20 cannot be discharged to the oil pot 1 through the oil inlet circuit 102). However, since the connection position A between the return oil circuit 101 and the hydraulic chamber 20 is located downstream (i.e., behind) of the connection position B between the oil inlet circuit 102 and the hydraulic chamber 20, the return oil circuit 101 remains connected to the hydraulic chamber 20, and then after the reflux valve 81 is opened, the brake fluid in the hydraulic chamber 20 can flow back to the oil pot 1 through the reflux oil circuit 101.

[0040] Furthermore, if Figure 1 As shown, in this embodiment, two hydraulic chambers 20 are provided in the brake master cylinder 2, and the two hydraulic chambers 20 are respectively a first hydraulic chamber 201 and a second hydraulic chamber 202; along the direction from the piston rod 21 of the brake master cylinder 2 to its piston 22, the first hydraulic chamber 201 is located upstream of the second hydraulic chamber 202.

[0041] There are two oil inlet circuits 102. The first hydraulic chamber 201 is connected to the oil pot 1 through one oil inlet circuit 102, and the second hydraulic chamber 202 is connected to the oil pot 1 through another oil inlet circuit 102. The return oil circuit 101 and the pedal simulator 3 are both connected to the first hydraulic chamber 201 (of course, both can also be connected to the second hydraulic chamber 202). A maintenance valve 87 is provided on one of the oil inlet circuits 102 for maintenance.

[0042] The wheel brake unit 5 includes a left front wheel brake 51, a right front wheel brake 52, a left rear wheel brake 53 and a right rear wheel brake 54; there are two first brake oil circuits 105, each of which is provided with a first brake control valve 83, the first hydraulic chamber 201 is connected to the right front wheel brake 52 and the left rear wheel brake 53 respectively through a first brake oil circuit 105, and the second hydraulic chamber 202 is connected to the left front wheel brake 51 and the right rear wheel brake 54 respectively through another first brake oil circuit 105.

[0043] There are two second brake oil circuits 106, each of which is provided with a second brake control valve 84. The electric booster device 4 is connected to the right front wheel brake 52 and the left rear wheel brake 53 through one of the second brake oil circuits 106, and the electric booster device 4 is connected to the left front wheel brake 51 and the right rear wheel brake 54 through the other second brake oil circuit 106.

[0044] Furthermore, if Figure 1 and Figure 2As shown, in this embodiment, the hydraulic brake system also includes four branch oil circuits 107, wherein one first brake oil circuit 105 and one second brake oil circuit 106 are connected in parallel and then connected to the right front wheel brake 52 and the left rear wheel brake 53 respectively through two of the branch oil circuits 107, and another first brake oil circuit 105 and another second brake oil circuit 106 are connected in parallel and then connected to the left front wheel brake 51 and the right rear wheel brake 54 respectively through the other two branch oil circuits 107. At the same time, each branch oil circuit 107 is provided with a normally open valve 85, and each branch oil circuit 107 is also connected to the oil pot 1 through an ABS valve 86 (specifically connected to the oil pot 1 through the oil delivery oil circuit 104) to play the ABS anti-lock function (the working principle of the ABS valve 86 can refer to the prior art, which will not be repeated here). The normally open valve 85 and the ABS valve 86 are both connected to the control unit 9 (specifically, the electrical signal connection), and the control unit 9 can control the opening and closing of the normally open valve 85 and the ABS valve 86.

[0045] Furthermore, if Figure 1 and Figure 2 As shown, in this embodiment, a first pressure sensor 88 is provided on the first brake oil circuit 105 for detecting the brake pressure of the brake master cylinder 2. A second pressure sensor 89 is provided on the second brake oil circuit 106 for detecting the brake pressure of the electric booster device 4. The first pressure sensor 88 and the second pressure sensor 89 are both connected to the control unit 9 (specifically, electrical signal connection).

[0046] Furthermore, if Figure 1 and Figure 2 As shown, in this embodiment, a pedal displacement sensor 61 is provided on the piston rod 21 of the brake master cylinder 2. The pedal displacement sensor 61 is used to detect the pedal stroke, pedal movement speed, etc. of the brake pedal 6, so as to obtain the driver's braking intention. The control unit 9 is respectively connected to the pedal displacement sensor 61 and the electric supercharger 4 (specifically, an electrical signal connection). The control unit 9 is used to control the pressurization pressure of the brake fluid by the electric supercharger 4 according to the pedal stroke and / or pedal movement speed detected by the pedal displacement sensor 61. For example, when the pedal displacement sensor 61 detects that the pedal stroke is large and the pedal movement speed is fast, it means that the driver wants the vehicle to have a large deceleration. At this time, the control unit 9 controls the electric supercharger 4 to increase the pressurization pressure of the brake fluid to achieve a rapid braking effect.

[0047] Specifically, in this embodiment, the electric supercharger 4 includes a motor 41 and a hydraulic pump 42. The motor 41 is connected to the hydraulic pump 42 through a transmission assembly 43 (the transmission assembly 43 is, for example, a ball screw structure); the motor 41 is connected to the control unit 9 by electrical signals, and the control unit 9 controls the operation of the motor 41 (including controlling the speed and forward and reverse rotation of the motor 41). When the motor 41 is running, the transmission assembly 43 converts its rotational motion into the linear motion of the piston in the hydraulic pump 42, thereby pressurizing the brake fluid. A position sensor 44 is provided on the motor 41, and the position sensor 44 is used to detect the rotation angle and speed of the motor 41. The specific structure and working principle of the electric supercharger 4 can be referred to the prior art, which will not be repeated here.

[0048] Furthermore, if Figure 2 As shown, in this embodiment, the hydraulic brake system further includes a mode switching unit 91, which is connected to the control unit 9; the control unit 9 has a first working mode and a second working mode, and the mode switching unit 91 is used to control the control unit 9 to switch between the first working mode and the second working mode;

[0049] When the control unit 9 is in the first working mode, the control unit 9 controls the return valve 81 to always be in a closed state; when the control unit 9 is in the second working mode, the control unit 9 controls the opening and closing of the return valve 81 according to the braking efficiency of the vehicle braking device during braking.

[0050] Specifically, the mode switching unit 91 may be a control element such as a button, a knob, a handle, or a vehicle computer provided on the vehicle. By operating the mode switching unit 91, the control unit 9 may be switched between the first working mode and the second working mode, thereby determining whether to enable the braking efficiency sensing function of the hydraulic brake system. For example, the vehicle may be set to a track mode, which corresponds to the second working mode. When the vehicle is turned on the track mode, the braking efficiency sensing function of the hydraulic brake system is enabled; however, under normal operating conditions, the vehicle does not need to enable the braking efficiency sensing function of the hydraulic brake system.

[0051] The hydraulic brake system in this embodiment has a mechanical hydraulic brake mode and an electric power-assisted brake mode. The following specifically describes the working process of the hydraulic brake system:

[0052] (1) Under normal circumstances, the hydraulic brake system is in the electric power-assisted braking mode. When the vehicle brakes, after the driver steps on the brake pedal 6, the control unit 9 obtains the brake signal through the pedal displacement sensor 61. At this time, the control unit 9 controls the first brake control valve 83 to close, the simulator control valve 82 and the second brake control valve 84 to open, and the electric booster 4 to operate. The electric booster 4 sucks the hydraulic oil in the oil tank 1 and pressurizes the hydraulic oil before entering the wheel brake unit 5 to brake the wheels; at the same time, the brake fluid in the hydraulic chamber 20 of the brake master cylinder 2 enters the pedal simulator 3 through the simulator control valve 82 to provide the driver with feedback on the pedal feel (the specific structure and working principle of the pedal simulator 3 can be found in the prior art and will not be repeated here).

[0053] Under some working conditions, for example, when the temperature of the vehicle's brake device is too high, when the braking efficiency of the vehicle's brake device is less than the standard braking efficiency, the control unit 9 controls the reflux valve 81 to open, so that part of the brake fluid in the hydraulic chamber 20 of the brake master cylinder 2 flows back to the oil tank 1 through the reflux oil circuit 101, thereby increasing the stroke of the brake pedal 6 and allowing the driver to sense the attenuation of the braking efficiency of the vehicle's brake device.

[0054] (2) In the event of failure of the electric power-assisted braking system, such as damage to the electric booster device 4, the hydraulic braking system switches to the traditional mechanical hydraulic braking mode (i.e., the mechanical hydraulic braking mode can play a role in safety backup braking). When the vehicle is braking, after the driver steps on the brake pedal 6, the control unit 9 obtains the braking signal through the pedal displacement sensor 61. At this time, the control unit 9 controls the first brake control valve 83 to open, the simulator control valve 82 and the second brake control valve 84 to close, the electric booster device 4 does not operate, and the high-pressure brake fluid in the hydraulic chamber 20 of the brake master cylinder 2 passes through the first brake control valve 83 and enters the wheel brake unit 5 to brake the wheels.

[0055] The embodiment of the present invention further provides a vehicle, comprising the above-mentioned hydraulic brake system. The vehicle may be an electric vehicle, a fuel vehicle, or the like.

[0056] The hydraulic braking system provided by the embodiment of the present invention is configured by setting a return oil circuit 101 between the oil pot 1 and the hydraulic chamber 20 of the brake master cylinder 2, and setting a return valve 81 on the return oil circuit 101; during braking, when the braking efficiency of the vehicle braking device decays (for example, the braking efficiency of the vehicle braking device decays to less than the standard braking efficiency), the control unit 9 controls the return valve 81 to open, so that part of the brake fluid in the hydraulic chamber 20 of the brake master cylinder 2 can flow back to the oil pot 1 through the return oil circuit 101. When the driver's pedaling force on the brake pedal 6 is constant, the stroke of the brake pedal 6 becomes longer, that is, the hydraulic braking system can increase the stroke of the brake pedal 6 when the braking efficiency of the vehicle braking device decays, so that the driver can perceive the decay of the braking efficiency of the vehicle braking device, and then the driver can react in advance when the braking efficiency decays, thereby improving driving safety.

[0057] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A hydraulic brake system, comprising an oil pot (1), a brake master cylinder (2), a pedal simulator (3), an electric booster (4), a wheel brake unit (5), a brake pedal (6) and a control unit (9); the piston rod (21) of the brake master cylinder (2) is connected to the brake pedal (6), the hydraulic chamber (20) of the brake master cylinder (2) is respectively connected to the oil pot (1), the pedal simulator (3) and the wheel brake unit (5); the electric booster (4) is respectively connected to the oil pot (1) and the wheel brake unit (5); characterized in that, The hydraulic brake system further comprises a return oil circuit (101), the two ends of which are respectively connected to the oil pot (1) and the hydraulic chamber (20) of the brake master cylinder (2), and a return valve (81) is provided on the return oil circuit (101); the control unit (9) is connected to the return valve (81), and the control unit (9) is used to control the opening and closing of the return valve (81) according to the braking efficiency of the vehicle brake device during braking; when the return valve (81) is opened, the brake fluid in the hydraulic chamber (20) of the brake master cylinder (2) can flow back to the oil pot (1) through the return oil circuit (101).

2. The hydraulic brake system according to claim 1, characterized in that: The return valve (81) is a normally closed valve; when the braking efficiency of the vehicle brake device decays to less than the standard braking efficiency, the control unit (9) controls the return valve (81) to open.

3. The hydraulic brake system according to claim 1, characterized in that: After the return valve (81) is opened for a rated time, the control unit (9) controls the return valve (81) to close, so as to stop the brake fluid in the hydraulic chamber (20) of the brake master cylinder (2) from flowing back to the oil tank (1) through the return oil circuit (101).

4. The hydraulic brake system according to claim 1, characterized in that: The brake master cylinder (2) is provided with at least two hydraulic chambers (20), each of which is connected to the oil pot (1) and the wheel brake unit (5) respectively; the return oil circuit (101) is connected to one or more of the hydraulic chambers (20).

5. The hydraulic brake system according to claim 4, characterized in that: The return oil circuit (101) is connected to one of the hydraulic chambers (20), and the return oil circuit (101) and the pedal simulator (3) are connected to the same hydraulic chamber (20).

6. The hydraulic brake system according to claim 1, characterized in that: The hydraulic chamber (20) of the brake master cylinder (2) is connected to the oil pot (1) via an oil inlet circuit (102); the oil inlet circuit (102) and the return circuit (101) are independent circuits; and in the direction from the piston rod (21) of the brake master cylinder (2) to its piston (22), the connection position of the return circuit (101) and the hydraulic chamber (20) is located downstream of the connection position of the oil inlet circuit (102) and the hydraulic chamber (20).

7. The hydraulic brake system according to claim 1, characterized in that: The hydraulic brake system further comprises a vehicle speed sensor (71), the vehicle speed sensor (71) being used to detect vehicle speed, the control unit (9) being connected to the vehicle speed sensor (71); the control unit (9) being used to calculate the vehicle deceleration according to the vehicle speed detected by the vehicle speed sensor (71) during braking, and to calculate the braking efficiency of the vehicle brake device according to the vehicle deceleration; And / or, the hydraulic brake system further comprises a temperature sensor (72), wherein the temperature sensor (72) is used to detect the temperature of the vehicle brake device, and the control unit (9) is connected to the temperature sensor (72); the control unit (9) is used to calculate the braking efficiency of the vehicle brake device according to the temperature detected by the temperature sensor (72) during braking.

8. The hydraulic brake system according to claim 1, characterized in that: The hydraulic brake system further comprises a mode switching unit (91), wherein the mode switching unit (91) is connected to the control unit (9); the control unit (9) has a first working mode and a second working mode, and the mode switching unit (91) is used to control the control unit (9) to switch between the first working mode and the second working mode; When the control unit (9) is in the first working mode, the control unit (9) controls the return valve (81) to always be in a closed state; when the control unit (9) is in the second working mode, the control unit (9) controls the opening and closing of the return valve (81) according to the braking efficiency of the vehicle braking device during braking.

9. The hydraulic brake system according to any one of claims 1 to 8, characterized in that: The hydraulic chamber (20) of the brake master cylinder (2) is connected to the pedal simulator (3) via an induction oil circuit (103), and a simulator control valve (82) is provided on the induction oil circuit (103); the hydraulic chamber (20) of the brake master cylinder (2) is connected to the wheel brake unit (5) via a first brake oil circuit (105), and a first brake control valve (83) is provided on the first brake oil circuit (105); the electric booster device (4) is connected to the wheel brake unit (5) via a second brake oil circuit (106), and a second brake control valve (84) is provided on the second brake oil circuit (106); The control unit (9) is respectively connected to the simulator control valve (82), the first brake control valve (83) and the second brake control valve (84), and the control unit (9) is used to control the opening and closing of the simulator control valve (82), the first brake control valve (83) and the second brake control valve (84).

10. A vehicle, characterized in that: Comprising a hydraulic brake system as claimed in any one of claims 1 to 9.

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