Hydraulic integrated brake-by-wire system

Abstract

The invention provides a hydraulic integrated brake-by-wire system, and belongs to the field of automobile brake systems, the hydraulic integrated brake-by-wire system comprises a main cylinder, a first piston, a second piston, a first oil can, a second oil can and an energy accumulator, the first piston and the second piston divide an inner cavity of the main cylinder into a first cavity, a second cavity and a third cavity, and the end, away from the main cylinder, of the first piston is connected with a pedal; a first loop and a second loop are connected between the second cavity and the wheel cylinder set, a third loop is connected between the first cavity and the wheel cylinder set, an oil pump is connected to the first loop in series, the energy accumulator is located between the oil pump and the second cavity, the first oil can is communicated with the first cavity through a pipeline, and the second oil can is communicated with the second cavity and the wheel cylinder set through pipelines. And the first oil pot and the second oil pot are mutually independent. The problem that an existing electronic hydraulic braking system is limited in redundancy capacity is solved. The method has the technical effects that reliable voltage buildup with higher power and higher braking response speed are realized, and the braking effect of redundant braking is ensured while braking decoupling is realized.

Description

Technical Field

[0001] The invention relates to the technical field of automobile braking systems, and in particular to a hydraulic integrated wire-controlled brake system. Background Art

[0002] As the performance level and maturity of intelligent driving systems gradually improve, in order to meet the L3 level's demand for redundant braking, that is, the vehicle must have the backup capability of wire-controlled braking. The existing braking system can only achieve mechanical braking backup capability, which cannot meet the needs of high-level autonomous driving. The current redundant solution is the IPB+RBU solution, that is, on the basis of the existing onebox, a new RBU is added, which is equivalent to a pressure building unit for backup pressure building. The cost is high and the redundancy capacity is limited. It is difficult to be accepted by the mainstream market to achieve redundancy by adding a pressure building unit.

[0003] In addition, the existing redundant braking solutions cannot achieve the desired braking efficiency while ensuring braking performance and driving feel. Summary of the invention

[0004] The present invention provides a hydraulic integrated brake-by-wire system to solve the defect of limited redundancy capacity of the hydraulic integrated brake-by-wire system in the prior art, and realizes reliable pressure building with greater power, faster braking response speed, and braking decoupling while ensuring the braking effect of redundant braking.

[0005] The present invention provides a hydraulic integrated brake-by-wire system, comprising a master cylinder, a first piston, a second piston, an oil pump, a wheel cylinder group, a first circuit, a second circuit, a third circuit, a first oil pot, a second oil pot, an accumulator and a pedal; The first piston and the second piston divide the chamber in the master cylinder into a first chamber, a second chamber and a third chamber; The end of the first piston away from the master cylinder is connected to a pedal, and the end surface action area of ​​the second piston in the first chamber is smaller than the end surface action area of ​​the second piston in the second chamber; A first circuit is connected between the second oil pot and the wheel cylinder group, a second circuit is connected between the second chamber and the wheel cylinder group, and a third circuit is connected between the first chamber and the wheel cylinder group; The first circuit is connected in parallel with an oil pump, an accumulator and a second chamber through pipelines. The accumulator is located between the oil pump and the second chamber. The first oil pot is connected to the first chamber through a pipeline. The first oil pot and the second oil pot are independent of each other.

[0006] In addition, the hydraulic integrated brake-by-wire system according to the present invention may also have the following additional technical features: In some embodiments of the present invention, a servo valve is further included. The second chamber is provided with a servo valve. The servo valve is connected in parallel with the first circuit through a pipeline. One end of the second circuit away from the wheel cylinder group is connected to the servo valve.

[0007] In some embodiments of the present invention, a relief valve is further included. The relief valve is connected in parallel with the first circuit through a pipeline, and the accumulator is located between the relief valve and the oil pump.

[0008] In some embodiments of the present invention, a first normally closed valve, a first normally open valve and a second normally open valve are further included. The second normally open valve is connected in parallel to the second circuit via a pipeline, the first normally open valve is connected in series to the third circuit, and the first normally closed valve is connected in parallel between the second circuit and the third circuit via a pipeline.

[0009] In some embodiments of the present invention, a pedal simulator and a second normally closed valve are also included. The pipeline between the second chamber and the second normally open valve is connected in parallel with the pedal simulator through a pipeline. The pipeline between the pedal simulator and the second chamber is connected in parallel with a third chamber and the second normally closed valve in sequence through two pipelines.

[0010] In some embodiments of the present invention, a first linear boost valve and a linear pressure reducing valve are also included. A linear pressure reducing valve is also connected in parallel to the first circuit through a pipeline. One end of the first linear boost valve is connected to a servo valve through a pipeline, and the other end of the first linear boost valve is connected between an oil pump and an accumulator through a pipeline. One end of the linear pressure reducing valve is connected to the servo valve through a pipeline, and the other end of the linear pressure reducing valve is connected between the oil pump and a wheel cylinder group through a pipeline.

[0011] In some embodiments of the present invention, a normally closed valve group is further included. The first circuit is connected in series with the normally closed valve group. The oil pump is connected in parallel with the linear pressure reducing valve, then connected in series with the normally closed valve group, and then connected in series with the wheel cylinder group.

[0012] In some embodiments of the present invention, a stroke sensor is further included, and the first piston is provided with a stroke sensor.

[0013] In some embodiments of the present invention, a first boost valve group and a second boost valve group are further included, the first boost valve group is connected in series to the second circuit, and the second boost valve group is connected in series to the third circuit.

[0014] In some embodiments of the invention, the relief valve is a mechanical relief valve.

[0015] This application includes the following beneficial technical effects: First, by making the end surface effective area of ​​the second piston in the first chamber smaller than the end surface effective area of ​​the second piston in the second chamber, the brake system can realize reliable and convenient pressure building, brake decoupling and other functions.

[0016] Second, the setting of the accumulator provides the braking system with sufficient redundant braking pressure, which not only meets the braking efficiency but also ensures the braking performance and driving feel.

[0017] Thirdly, the redundant braking and mechanical braking fluid storage are backed up by the arrangement of the first oil pot and the second oil pot, thereby ensuring the braking effect of the redundant braking and the mechanical braking.

[0018] Fourth, achieve more powerful reliable pressure build-up, faster braking response speed, brake decoupling and ensure the braking effect of redundant braking. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Moreover, the same reference numerals are used throughout the accompanying drawings to represent the same components. In the accompanying drawings: Figure 1 The working principle diagram of the hydraulic integrated brake-by-wire system in a natural state according to some embodiments of the present invention is schematically shown.

[0020] Figure 2 The working principle diagram of conventional braking of a hydraulically integrated brake-by-wire system according to some embodiments of the present invention is schematically shown.

[0021] Figure 3 The working principle diagram of the redundant braking mode of the power-off-activated backup energy storage of the hydraulically integrated brake-by-wire system according to some embodiments of the present invention is schematically shown.

[0022] Figure 4 The working principle diagram of the mechanical braking mode when power is lost and redundant braking fails in a hydraulic integrated brake-by-wire system according to some embodiments of the present invention is schematically shown.

[0023] Figure 5 The flowchart schematically shows the working process of the electronic hydraulic braking mode of the hydraulic integrated wire control brake system according to some embodiments of the present invention.

[0024] Reference numerals: 1. Solenoid valve group, 101. Third normally closed valve, 102. Fourth normally closed valve, 103. Fifth normally closed valve, 104. Sixth normally closed valve, 105. First normally closed valve, 106. Second normally open valve, 107. First normally open valve, 108. Second normally closed valve, 2. Linear valve group, 21. First linear boost valve, 22. Linear pressure reducing valve, 23. Second linear boost valve, 24. Third linear boost valve, 25. Fourth linear boost valve, 26. Fifth linear boost valve, 3. Master cylinder, 31. First chamber, 32. Second chamber chamber, 33, third chamber, 34, first piston, 35, second piston, 36, first oil pot, 37, second oil pot, 41, first sensor, 42, second sensor, 43, third sensor, 5, pedal simulator, 6, wheel cylinder group, 61, left rear wheel cylinder, 62, right rear wheel cylinder, 63, right front wheel cylinder, 64, left front wheel cylinder, 7, stroke sensor, 81, oil pump, 82, accumulator, 83, overflow valve, 91, pedal, 92, emergency braking system, 10, servo valve, 11, controller. DETAILED DESCRIPTION

[0025] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0026] It should be understood that the terms used herein are only for the purpose of describing specific example embodiments and are not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms "one", "an" and "" as used herein may also be meant to include plural forms. The terms "include", "comprise", "contain", and "have" are inclusive and therefore specify the presence of stated features, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, steps, operations, elements, parts, and / or combinations thereof. The method steps, processes, and operations described herein are not interpreted as necessarily requiring them to be performed in the specific order described or illustrated, unless the execution order is clearly indicated. It should also be understood that additional or alternative steps may be used.

[0027] Although the terms first, second, third, etc. can be used in the text to describe multiple elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms can only be used to distinguish an element, component, region, layer or section from another region, layer or section. Unless the context clearly indicates, terms such as "first", "second" and other numerical terms do not imply order or sequence when used in the text. Therefore, the first element, component, region, layer or section discussed below can be referred to as the second element, component, region, layer or section without departing from the teaching of the example embodiments.

[0028] For ease of description, spatial relative terms may be used in the text to describe the relationship of one element or feature relative to another element or feature as shown in the figure, such as "inside", "outside", "inner side", "outer side", "below", "below", "above", "above", etc. Such spatial relative terms are intended to include different orientations of the device in use or operation in addition to the orientation depicted in the figure. For example, if the device in the figure is flipped, the element described as "below other elements or features" or "below other elements or features" will then be oriented as "above other elements or features" or "above other elements or features". Therefore, the example term "below..." can include both upper and lower orientations. The device can be additionally oriented and rotated 90 degrees or in other directions and the spatial relative descriptors used in the text are interpreted accordingly.

[0029] like Figures 1 to 5 As shown, according to an embodiment of the first aspect of the present invention, a hydraulic integrated brake-by-wire system is provided, comprising a master cylinder 3, a first piston 34, a second piston 35, an oil pump 81, a wheel cylinder group 6, a first circuit, a second circuit, a third circuit, a first oil pot 36, a second oil pot 37, an accumulator 82 and a pedal 91; The first piston 34 and the second piston 35 divide the chamber in the master cylinder 3 into a first chamber 31, a second chamber 32 and a third chamber 33; The end of the first piston 34 away from the master cylinder 3 is connected to a pedal 91, and the end surface action area of ​​the second piston 35 in the first chamber 31 is smaller than the end surface action area of ​​the second piston 35 in the second chamber 32; A first circuit is connected between the second oil pot 37 and the wheel cylinder group, a second circuit is connected between the second chamber 32 and the wheel cylinder group 6, and a third circuit is connected between the first chamber 31 and the wheel cylinder group 6; The first circuit is connected in parallel with an oil pump 81, an accumulator 2 and a second chamber 32 through pipelines. The accumulator 82 is located between the oil pump 81 and the second chamber 32. The first oil pot 36 is connected to the first chamber 31 through pipelines. The first oil pot 36 and the second oil pot 37 are independent of each other.

[0030] In the above embodiment, it should be noted that the second piston 35 is a variable diameter piston, the end surface effective area of ​​the first piston 34 in the third chamber 33 is smaller than the end surface effective area of ​​the first piston in the first chamber 31; and the oil pump 81 is an intermittently driven pump by an electric motor.

[0031] The technical effect achieved by the above embodiment is: the pressure buildup and brake decoupling of the present braking system are achieved by making the end surface effective area of ​​the second piston 35 in the first chamber 31 smaller than the end surface effective area of ​​the second piston 35 in the second chamber 32 .

[0032] The arrangement of the accumulator 82 provides the present braking system with sufficient redundant braking pressure, which satisfies the braking efficiency while ensuring the braking performance and driving feel.

[0033] By independently arranging the first oil pot 36 and the second oil pot 37 , redundant braking and mechanical braking fluid storage can be backed up for each other, thereby ensuring the braking effect of redundant braking and mechanical braking.

[0034] Optional, such as Figures 1 to 4 As shown, a servo valve 10 is also included. The servo valve 10 is arranged in the second chamber 32 . The servo valve 10 is connected in parallel with the first circuit through a pipeline. The end of the second circuit away from the wheel cylinder group 6 is connected to the servo valve 10 .

[0035] In the above optional embodiment, it should be noted that the servo valve 10 is a two-position three-way slide valve.

[0036] The beneficial effect of the above optional embodiment is that the setting of the servo valve 10 can output a redundant pressure source for the braking system.

[0037] Optional, such as Figures 1 to 4 As shown, the system further includes a relief valve 83 , which is connected in parallel with the first circuit through a pipeline, and the accumulator 82 is located between the relief valve 83 and the oil pump 81 .

[0038] In the above optional embodiment, it should be noted that the overflow valve 83 is a mechanical overflow valve.

[0039] The beneficial effect of the above optional embodiment is that the provision of the overflow valve 83 enables timely adjustment of the pressure when the accumulator 82 is over-pressurized, thereby ensuring the service life of the accumulator 82 .

[0040] Optional, such as Figures 1 to 5As shown, it also includes a first normally closed valve 105, a first normally open valve 107 and a second normally open valve 106. The second normally open valve 106 is connected in parallel to the second circuit through a pipeline, the first normally open valve 107 is connected in series to the third circuit, and the first normally closed valve 105 is connected in parallel between the second circuit and the third circuit through a pipeline.

[0041] It also includes a pedal simulator 5 and a second normally closed valve 108. The pedal simulator 5 is connected in parallel on the pipeline between the second chamber 32 and the second normally open valve 106 through a pipeline. The pipeline between the pedal simulator 5 and the second chamber 32 is sequentially connected in parallel with the third chamber 33 and the second normally closed valve 108 through two pipelines. In addition, the pedal simulator 5 is connected in series with the second normally closed valve 108 and then in parallel with the first normally open valve 107.

[0042] A linear pressure reducing valve 22 is also connected in parallel to the first circuit through a pipeline. One end of the first linear pressure increasing valve 21 is connected to the servo valve 10 through the pipeline of the first circuit and then communicated with the chamber of the servo valve 10. The other end of the first linear pressure increasing valve 21 is connected between the oil pump 81 and the accumulator 82 through a pipeline. One end of the linear pressure reducing valve 22 is connected to the servo valve 10 through the pipeline of the first circuit and then communicated with the chamber of the servo valve 10. The other end of the linear pressure reducing valve 22 is connected between the oil pump 81 and the wheel cylinder group 6 through a pipeline.

[0043] The first piston 34 also includes a stroke sensor 7 . The first piston 34 is provided with the stroke sensor 7 .

[0044] It also includes a normally closed valve group. The normally closed valve group is connected in series on the first circuit. The oil pump 81 is connected in parallel with the linear pressure reducing valve 22, then connected in series with the normally closed valve group, and then connected in series with the wheel cylinder group 6.

[0045] The first boost valve group is connected in series to the second circuit, and the second boost valve group is connected in series to the third circuit.

[0046] In the above optional embodiment, it should be noted that the normally closed valve group includes the third normally closed valve 101, the fourth normally closed valve 102, the fifth normally closed valve 103 and the sixth normally closed valve 104, the wheel cylinder group includes the left rear wheel cylinder 61, the right rear wheel cylinder 62, the right front wheel cylinder 63 and the left front wheel cylinder 64; the first boost valve group includes the second linear boost valve 23 and the third linear boost valve 24; the second boost valve group includes the fourth linear boost valve 25 and the fifth linear boost valve 26; wherein the third normally closed valve 101, the fourth normally closed valve 102, the fifth normally closed valve 103 and the sixth normally closed valve 104 are all arranged on the first circuit and the third normally closed valve 101, the fourth normally closed valve 102, the fifth normally closed valve 103 and the sixth normally closed valve 104 are mutually connected. The third normally closed valve 101 is connected in series with the left rear wheel cylinder 61, the fourth normally closed valve 102 is connected in series with the right rear wheel cylinder 62, the fifth normally closed valve 103 is connected in series with the right front wheel cylinder 63, and the sixth normally closed valve 104 is connected in series with the left front wheel cylinder 64; the second linear booster valve 23 and the third linear booster valve 24 are connected in series with the servo valve 10 on the second circuit respectively and then connected in parallel with each other, the left rear wheel cylinder 61 is connected in series with the second linear booster valve 23, the right rear wheel cylinder 62 is connected in series with the third linear booster valve 24, the fourth linear booster valve 25 and the fifth linear booster valve 26 are connected in series with the second normally open valve 106 on the third circuit and then connected in parallel with each other, the right front wheel cylinder 63 is connected in series with the fourth linear booster valve 25, and the left front wheel cylinder 64 is connected in series with the fifth linear booster valve 26.

[0047] Furthermore, it also includes a first sensor 41, a second sensor 42 and a third sensor 43. The first sensor 41 is installed on the pipeline between the overflow valve 83 and the second chamber 32, the second sensor 42 is installed on the pipeline between the first linear boost valve 21 and the second chamber 32, and the third sensor 43 is installed on the pipeline between the pedal simulator 5 and the second chamber 32 and the third chamber 33, and the third sensor 43 is connected in parallel with the second normally closed valve 108; the first sensor 41, the second sensor 42 and the third sensor 43 are all pressure sensors.

[0048] In addition, it also includes a controller 11 and an emergency braking system 9. Specifically, a third normally closed valve 101, a fourth normally closed valve 102, a fifth normally closed valve 103, a sixth normally closed valve 104, a first normally closed valve 105, a second normally open valve 106, a first normally open valve 107 and a second normally closed valve 108 are combined to form a solenoid valve group 1, a first linear boost valve 21, a linear pressure reducing valve 22, a second linear boost valve 23, a third linear boost valve 24, a fourth linear boost valve 25 and a fifth linear boost valve 26 are combined to form a linear valve group 2, a stroke sensor 7, a first sensor 41, a second sensor 42, a third sensor The sensor 43, the third normally closed valve 101, the fourth normally closed valve 102, the fifth normally closed valve 103, the sixth normally closed valve 104, the first normally closed valve 105, the second normally open valve 106, the first normally open valve 107 and the second normally closed valve 108 of the solenoid valve group 1 and the first linear boost valve 21, the linear pressure reducing valve 22, the second linear boost valve 23, the third linear boost valve 24, the fourth linear boost valve 25 and the fifth linear boost valve 26 of the linear valve group 2 are all electrically connected to the controller 11; the third normally closed valve 101, the fourth normally closed valve 102, the fifth normally closed valve 103 and the sixth normally closed valve 104 are all pressure reducing valves.

[0049] The emergency braking system 9 is electrically connected to the controller 11 , and the emergency control system 9 is an existing ESP, emergency active braking or intelligent driving system.

[0050] The working principle of this device is: First, during normal braking, such as Figure 2 As shown, the electronic hydraulic braking mode includes conventional braking and active braking intervention.

[0051] During normal braking, the driver steps on the pedal 91, and the travel sensor 7 sends a braking signal to the controller 11. The controller 11 is powered on and the output pressure of the servo valve 10 is adjusted through the second linear booster valve 23, the third linear booster valve 24, the fourth linear booster valve 25 and the fifth linear booster valve 26. The oil pump 81 provides oil pressure from point S to point P to power the device. The first sensor 41 can keep the pressure of the accumulator 82 between the pressure Pa and Pb (Pb>Pa) by feeding back the signal to the controller 11.

[0052] The specific way in which the oil pump 81 supplies energy to the device is as follows: First, the hydraulic oil coming out of the second oil pot 37 passes through the first circuit, then enters the oil pump 81 through point S, and then enters point P to realize that the oil pump 81 supplies energy to the device.

[0053] The residual oil pressure in the second and third normally closed valves 101, the fourth normally closed valve 102, the fifth normally closed valve 103 and the sixth normally closed valve 104 enters the oil pump 81 from point S and then enters point S to supply energy to the device, thereby realizing the secondary utilization of the residual oil pressure to avoid waste.

[0054] The driver gets the pedal feeling from the feedback loop between the first chamber 31, the second chamber 32 and the third chamber 33 of the master cylinder 3 and the pedal simulator 5. The third sensor 43 and the stroke sensor 7 are redundant. At this time, the second normally closed valve 108 and the first normally closed valve 105 are electrically connected to the fluid, and the second normally open valve 106 and the first normally open valve 107 are electrically disconnected. At this time, the first chamber 31, the second chamber 32 and the third chamber 33 of the master cylinder 3 are all connected to the pedal simulator 5. Due to the difference in effective area between the front and rear of the second piston 35, the second piston 35 will not move to the left, that is, it will not change the volume of the first chamber. The movement of the first piston 34 will increase the volume of the third chamber 33 and reduce the volume of the first chamber 31 at the same time. However, due to the difference in area between the front and rear of the first piston 34, the first chamber 31 produces excess displacement, which is accommodated by the pedal simulator 5 and establishes feedback pressure, forming a pressure building loop.

[0055] Description of the brake circuit: The current regulating pressure of the first linear booster valve 21 and the linear pressure reducing valve 22 makes the pressure input to the servo valve 10 linearly, the servo output of the servo valve 10 opens, and the brake pressure enters the left rear wheel cylinder 61 and the right rear wheel cylinder 62 respectively through the second linear booster valve 23 and the third linear booster valve 24, and the brake pressure of the right front wheel cylinder 63 and the left front wheel cylinder 64 passes through the first normally closed valve 105 that has been electrically connected to the fluid and then is realized through the fourth linear booster valve 25 and the fifth linear booster valve 26 respectively.

[0056] The servo valve 10 is a two-position three-way slide valve. In the natural state, the slide valve is located at the right limit position under the action of the spring, and the second chamber 32 is connected to the second oil pot 37; when the power is on, the second chamber 32 is connected to the high pressure from the first linear boost valve 21 in a timely manner in a dynamic control process. The second linear boost valve 23, the third linear boost valve 24, the fourth linear boost valve 25, the fifth linear boost valve 26, the third normally closed valve 101, the fourth normally closed valve 102, the fifth normally closed valve 103, and the sixth normally closed valve 104 can distribute the braking force of a single wheel cylinder to realize functions such as ESP and vehicle electronic stability system.

[0057] When active braking acts alone, the controller 11 receives the command and directly operates the brake circuit, and the pedal will not move, that is, the pressure-building circuit will become normal pressure. At this time, the second normally closed valve 108 and the first normally closed valve 105 are powered on and fluid is passed, and the first normally open valve 107 and the second normally open valve 106 are powered on and closed. The current regulating pressure of the first linear booster valve 21 and the linear pressure reducing valve 22 makes the pressure linearly input to the second chamber 32, and the servo output of the servo valve 10 is opened, and the brake pressure enters the left rear wheel cylinder 61 and the right rear wheel cylinder 62 respectively through the second linear booster valve 23 and the third linear booster valve 24, and the brake pressure of the right front wheel cylinder 63 and the left front wheel cylinder 64 passes through the first normally closed valve 105 which has been powered on and fluid is respectively realized through the fourth linear booster valve 25 and the fifth linear booster valve 26. The third normally closed valve 101, the fourth normally closed valve 102, the fifth normally closed valve 103 and the sixth normally closed valve 104 can release the excess brake pressure to realize functions such as ESP.

[0058] It should be noted here that active braking can, but is not limited to, working synchronously with conventional braking.

[0059] Second, when the system loses power, the redundant braking of the backup energy storage is activated.

[0060] like Figure 3 As shown, at this time, the third normally closed valve 101, the fourth normally closed valve 102, the fifth normally closed valve 103, the sixth normally closed valve 104, the first normally closed valve 105, the second normally open valve 106, the first normally open valve 107, the second normally closed valve 108, the first linear boost valve 21, the linear pressure reducing valve 22, the second linear boost valve 23, the third linear boost valve 24, the fourth linear boost valve 25 and the fifth linear boost valve 26 are all in a natural state. When the driver performs conventional braking, the first chamber 31 builds pressure to push the second piston 35, and the second piston 35 mechanically triggers the servo valve 10, and the servo valve 10 outputs a redundant pressure source. The first branch of the brake pressure directly provides braking for the left rear wheel cylinder 61 and the right rear wheel cylinder 62. The second branch is transmitted to the third chamber 33 through the second normally open valve 106 to provide assistance to the first piston 34; the volume of the third chamber 33 changes, and the pressure is further transmitted to the braking force of the right front wheel cylinder 63 and the left front wheel cylinder 64 through the first normally open valve 107. The driver only needs to provide a small foot force to achieve a large braking force.

[0061] Here, if the brake circuits of the right front wheel cylinder 63 and the left front wheel cylinder 64 fail, the first piston 34 is mechanically connected to the second piston 35, and the rear wheel can still achieve normal braking, entering the second working condition of redundant braking, and the first chamber 31 to the front wheel becomes normal pressure, which will not be described in detail here.

[0062] Third, the system loses power, the redundant braking circuit fails, and the mechanical braking mode is reached.

[0063] like Figure 4 As shown, at this time, the third normally closed valve 101, the fourth normally closed valve 102, the fifth normally closed valve 103, the sixth normally closed valve 104, the first normally closed valve 105, the second normally open valve 106, the first normally open valve 107, the second normally closed valve 108, the first linear boost valve 21, the linear pressure reducing valve 22, the second linear boost valve 23, the third linear boost valve 24, the fourth linear boost valve 25 and the fifth linear boost valve 26 are all in a natural state. When the driver performs conventional braking, the pressure in the first chamber 31 builds up and pushes the second piston 35 to the limit position, the volume of the first chamber 31 changes, and the pressure is transmitted to the braking force of the right front wheel cylinder 63 and the left front wheel cylinder 64 through the first normally open valve 107, completing the mechanical braking.

[0064] In summary, the present invention has the following advantages: First, the present invention does not have a large reduction ratio mechanism, the system mechanical inertia is smaller, and the response speed is faster.

[0065] Second, the oil pump 81 and the accumulator 82 of the present invention are both hydraulic energy sources and can work independently and serve as backup for each other.

[0066] Third, the electrical system of this solution is relatively simple in structure, has high reliability and low cost.

[0067] Fourth, the displacement of this solution is not limited by the piston displacement and is more suitable for systems with large liquid requirements.

[0068] Fifth, this solution uses one oil pump 81 to solve the problem of high-frequency pressure regulation and pressure reduction, and has a simple structure and low cost.

[0069] Sixth, braking operation under various working conditions is achieved by setting the third normally closed valve 101, the fourth normally closed valve 102, the fifth normally closed valve 103, the sixth normally closed valve 104, the first normally closed valve 105, the second normally open valve 106, the first normally open valve 107, the second normally closed valve 108, the first linear boost valve 21, the linear pressure reducing valve 22, the second linear boost valve 23, the third linear boost valve 24, the fourth linear boost valve 25 and the fifth linear boost valve 26.

[0070] Seventh, the front and rear hydraulic balance is achieved through the variable diameter setting of the second piston 35 of the master cylinder 3, and the pressure buildup and brake circuit decoupling in the wire control braking mode are realized. The volume displacement / intake difference caused by the front and rear effective area difference of the first piston 34 is used to enter the pedal simulator 5 to build pressure.

[0071] Eighth, the brake fluid of the brake circuit during active braking comes from the second oil tank, the brake fluid of the pressure-building circuit comes from the first chamber, and the corresponding redundant brake and mechanical brake fluid storages back up each other.

[0072] Ninth, the accumulator 82 cooperates with the large-flux servo valve 10 to quickly respond to the braking requirements of large-displacement wheel cylinders, and the upper limit of the braking vehicle model is increased accordingly.

[0073] Tenth, in the redundant braking mode, the accumulator 82 provides sufficient brake fluid pressure, which not only meets the braking efficiency but also helps to ensure the braking performance and driving feel.

[0074] The above are only preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A hydraulic integrated brake-by-wire system, characterized in that: It comprises a master cylinder (3), a first piston (34), a second piston (35), an oil pump (81), a wheel cylinder group (6), a first circuit, a second circuit, a third circuit, a first oil pot (36), a second oil pot (37), an accumulator (82) and a pedal (91); The first piston (34) and the second piston (35) divide the chamber in the master cylinder (3) into a first chamber (31), a second chamber (32) and a third chamber (33); The end of the first piston (34) away from the master cylinder (3) is connected to the pedal (91), and the end surface action area of ​​the second piston (35) in the first chamber (31) is smaller than the end surface action area of ​​the second piston (35) in the second chamber (32); A first circuit is connected between the second oil pot (37) and the wheel cylinder group, a second circuit is connected between the second chamber (32) and the wheel cylinder group (6), and a third circuit is connected between the first chamber (31) and the wheel cylinder group (6); The oil pump (81), the accumulator (2) and the second chamber (32) are connected in parallel on the first circuit via a pipeline; the accumulator (82) is located between the oil pump (81) and the second chamber (32); the first oil pot (36) is connected to the first chamber (31) via a pipeline; and the first oil pot (36) and the second oil pot (37) are independent of each other.

2. The hydraulic integrated brake-by-wire system according to claim 1, characterized in that: It also comprises a servo valve (10), wherein the servo valve (10) is arranged in the second chamber (32), the servo valve (10) is connected in parallel with the first circuit via a pipeline, and the end of the second circuit away from the wheel cylinder group (6) is connected to the servo valve (10).

3. The hydraulic integrated brake-by-wire system according to claim 2, characterized in that: It also includes a relief valve (83), the relief valve (83) being connected in parallel with the first circuit via a pipeline, and the accumulator (82) being located between the relief valve (83) and the oil pump (81).

4. The hydraulic integrated brake-by-wire system according to claim 1, characterized in that: The device further comprises a first normally closed valve (105), a first normally open valve (107) and a second normally open valve (106); the second normally open valve (106) is connected in parallel to the second circuit via a pipeline; the first normally open valve (107) is connected in series to the third circuit; and the first normally closed valve (105) is connected in parallel between the second circuit and the third circuit via a pipeline.

5. The hydraulic integrated brake-by-wire system according to claim 4, characterized in that: The invention also comprises a pedal simulator (5) and a second normally closed valve (108); the pipeline between the second chamber (32) and the second normally open valve (106) is connected in parallel with the pedal simulator (5) via a pipeline; the pipeline between the pedal simulator (5) and the second chamber (32) is connected in parallel with the third chamber (33) and the second normally closed valve (108) via two pipelines.

6. The hydraulic integrated brake-by-wire system according to claim 2, characterized in that: The invention also comprises a first linear pressure-increasing valve (21) and a linear pressure-reducing valve (22); the first circuit is connected in parallel with the linear pressure-reducing valve (22) via a pipeline; one end of the first linear pressure-increasing valve (21) is connected to the servo valve (10) via a pipeline; the other end of the first linear pressure-increasing valve (21) is connected between the oil pump (81) and the accumulator (82) via a pipeline; one end of the linear pressure-reducing valve (22) is connected to the servo valve (10) via a pipeline; the other end of the linear pressure-reducing valve (22) is connected between the oil pump (81) and the wheel cylinder group (6) via a pipeline.

7. The hydraulic integrated brake-by-wire system according to claim 6, characterized in that: It also includes a normally closed valve group, the first circuit is connected in series with the normally closed valve group, the oil pump (81) is connected in parallel with the linear pressure reducing valve (22), then connected in series with the normally closed valve group, and then connected in series with the wheel cylinder group (6).

8. The hydraulic integrated brake-by-wire system according to any one of claims 1 to 7, characterized in that: It also includes a stroke sensor (7), and the first piston (34) is provided with the stroke sensor (7).

9. The hydraulic integrated brake-by-wire system according to any one of claims 1 to 7, characterized in that: The first boost valve group is connected in series to the second circuit, and the second boost valve group is connected in series to the third circuit.

10. The hydraulic integrated brake-by-wire system according to claim 3, characterized in that: The overflow valve (83) is a mechanical overflow valve.

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