Brake master cylinder and brake system

Abstract

The utility model discloses a brake master cylinder and brake system, brake master cylinder includes cylinder body and sets up piston subassembly in the inner chamber of cylinder body, cylinder body is the cavity of two ends opening, is equipped with the plug at one end, and the other end is connected with piston subassembly sliding, is installed with the oil can on the cylinder body, piston subassembly includes first piston and second piston sliding connection with cylinder inner chamber respectively, one end of first piston is through first spring and is abutted with the plug, and the other end is through second spring and is abutted with second piston, and one end of second piston away from first piston extends to the outside of cylinder body, the outer peripheral wall of first piston near the one end of plug is the taper surface, is seted up with the first oil supply opening between the plug and first piston on the cylinder body, and the second oil supply opening between first piston and second piston, the utility model discloses setting cylinder body as the cavity of two ends opening, has reduced the assembly difficulty of piston subassembly and the difficulty of later maintenance.

Description

Technical Field

[0001] This utility model relates to the field of automotive braking technology, specifically to a brake master cylinder and braking system. Background Technology

[0002] With the development of vehicle electrification and intelligence, the demand for intelligent chassis, especially electronic braking, is constantly increasing. Vehicle electrification has led to the replacement of the vacuum source solutions required by traditional vacuum boosters, making electronic power steering a trend. Among them, BOSCH's ibooster electronic power booster (i.e., electronic brake booster) uses the actual hydraulic braking force to be formed by the superposition and coupling of the brake pedal input force and the boost (vacuum or electronic boost).

[0003] The push rod of the electronic brake booster is suitable for connection to the brake master cylinder. The existing brake master cylinder has a structure with one open end and one sealed end. A piston assembly is installed inside the cylinder. This one-end-open-and-one-sealed structure makes it difficult to disassemble and assemble the piston assembly; that is, the existing brake master cylinder is difficult to disassemble and assemble. If the piston assembly needs to be repaired, the brake master cylinder must be completely separated from the electronic brake booster to remove the piston assembly, making the operation complex and cumbersome. Utility Model Content

[0004] This utility model proposes a brake master cylinder and a braking system to solve the technical problem that existing brake master cylinders are inconvenient to disassemble and assemble piston assemblies and are inconvenient to maintain.

[0005] On the one hand, this utility model discloses a brake master cylinder, which is suitable for mounting on an electronic brake booster. The brake master cylinder includes a cylinder body and a piston assembly disposed in the inner cavity of the cylinder body. The cylinder body is a cavity with openings at both ends, one end of which is provided with a plug, and the other end is slidably connected to the piston assembly; an oil can is installed on the cylinder body and communicates with the inner cavity of the cylinder body. The piston assembly includes a first piston and a second piston that are slidably connected to the inner cavity of the cylinder; one end of the first piston abuts against the plug via a first spring, and the other end of the first piston abuts against the second piston via a second spring; the end of the second piston away from the first piston extends out of the cylinder. The outer peripheral wall of the first piston near the end of the plug is a conical surface; The cylinder body has a first oil supply port located between the plug and the first piston, and a second oil supply port located between the first piston and the second piston. By setting the cylinder body as a cavity with openings at both ends, the assembly difficulty of the piston assembly and the difficulty of subsequent maintenance are reduced; the operator does not need to remove the master cylinder from the electronic brake booster, but can perform maintenance by simply removing the plug.

[0006] Furthermore, a first groove is formed at one end of the first piston near the first spring; one end of the first spring is placed in the first groove and abuts against the first piston, and the other end abuts against the plug through the first spring seat; The inner ring of the first spring is provided with a first limiting screw, the screw head of the first limiting screw is placed in the first spring seat, and its screw passes through the first spring seat and is threadedly connected to the first piston. The second piston has a second groove at one end near the second spring, and the other end extends out of the cylinder body; one end of the second spring is placed in the second groove and abuts against the second piston, and the other end abuts against the first piston through the second spring seat; The inner ring of the second spring is provided with a second limiting screw. The head of the second limiting screw is placed inside the second spring seat, and its screw passes through the second spring seat and is threadedly connected to the second piston. This design reduces the difficulty of assembling the spring.

[0007] Furthermore, a first radial through hole and a second radial through hole are respectively formed on the peripheral walls of the first groove and the second groove; The first radial through holes are distributed on the conical surface of the first piston; The second piston includes a mating section, a conical section, and an extension section extending out of the cylinder body, which are connected sequentially along its axial direction; the mating section and the extension section are slidably connected to the cylinder body, respectively. The second radial through-hole is distributed on the conical section of the second piston. This design ensures smooth sliding of the second piston.

[0008] Furthermore, the first radial through holes are distributed at equal angles with the axis of the first piston as the center; The second radial through holes are distributed at equal angles with the axis of the second piston as the center.

[0009] Furthermore, the angle between the conical surface of the first piston and the central axis of the first piston is 3° to 15°. The angle between the conical surface of the second piston conical section and the central axis of the second piston is 3° to 8°.

[0010] Furthermore, the cylinder body is provided with the first oil supply port, the first connecting hole, the second oil supply port and the second connecting hole in sequence along its axial direction; A first sealing ring is provided between the first oil supply port and the first connecting hole; a second sealing ring is provided between the first connecting hole and the second oil supply port; a third sealing ring is provided between the second oil supply port and the second connecting hole; a fourth sealing ring is provided on the side of the second connecting hole away from the third sealing ring; the first sealing ring, the second sealing ring, the third sealing ring and the fourth sealing ring are all embedded in the inner cavity of the cylinder body; The oil reservoir is connected to the inner cavity of the cylinder body through the first connecting hole and the second connecting hole; the first piston is adapted to open or close the first connecting hole, and the second piston is adapted to open or close the second connecting hole. This design allows the brake master cylinder to perform either an oil intake or an oil discharge action.

[0011] Furthermore, the inner cavity of the cylinder includes a first cavity, a second cavity, and a third cavity arranged sequentially along its axial direction; The first oil supply port and the first connecting hole are disposed in the first cavity, and the first piston is slidably connected to the first cavity; The second oil supply port is located in the second cavity, and the inner diameter of the second cavity is larger than the outer diameter of the first piston and the outer diameter of the second piston, respectively. The second connecting hole is disposed in the third cavity, and the second piston is slidably connected to the first cavity. Using the above solution, Furthermore, a first annular groove matching the first connecting hole is formed inside the first cavity; The third cavity is provided with a second annular groove that matches the second connecting hole. This design reduces the difficulty of connecting the connecting hole on the cylinder block to the radial through hole on the piston.

[0012] Furthermore, a connecting lug is provided at the end of the cylinder block away from the plug, and the connecting lug is distributed on both sides of the second oil supply port. With this design, the distribution of the connecting lugs will not affect the connection between the second oil supply port and the external pipeline.

[0013] On the other hand, this utility model also discloses a braking system, including an electronic brake booster and the aforementioned brake master cylinder; The cylinder body of the brake master cylinder is located outside the housing of the electronic brake booster and is mounted on the housing; The second piston of the brake master cylinder extends into the housing at the end furthest from the first piston and abuts against the push rod of the electronic brake booster.

[0014] By adopting the above technical solution, this utility model has the following beneficial effects compared with the prior art: By designing the cylinder body as a cavity with openings at both ends, the assembly difficulty of the piston assembly and the difficulty of subsequent maintenance are reduced; the staff does not need to remove the master cylinder from the electronic brake booster, but can carry out maintenance by simply removing the plug. The outer peripheral wall of the first piston near the end of the plug is tapered, so that the first piston can be installed in the inner cavity of the cylinder and the hydraulic oil in the oil reservoir can enter the inner cavity of the cylinder. The difficulty of connecting the first connecting hole and the first radial through hole is reduced by the fit between the first annular groove and the first piston conical surface; the difficulty of connecting the second connecting hole and the second radial through hole is reduced by the fit between the second annular groove and the second piston conical surface section.

[0015] The above description of the disclosed content and the following description of the embodiments are intended to demonstrate and explain the spirit and principle of the present invention, and to provide a further explanation of the scope of the patent application of the present invention. Attached Figure Description

[0016] The specific embodiments of this utility model will be further described in detail below with reference to the accompanying drawings.

[0017] Figure 1 This is a schematic diagram of the brake master cylinder in this utility model; Figure 2 This is a cross-sectional view of the brake master cylinder in this utility model; Figure 3 This is a cross-sectional view of the cylinder body in this utility model; Figure 4 This is a schematic diagram of the piston assembly in this utility model; Figure 5 This is a schematic diagram of the braking system in this utility model.

[0018] Explanation of icon numbers: 1. Cylinder block; 11. First oil supply port; 12. First connecting hole; 13. Second oil supply port; 14. Second connecting hole; 15. First annular groove; 16. Second annular groove; 17. Connecting lug; 2. Piston assembly; 21. First spring; 22. First piston; 221. First groove; 222. First radial through hole; 23. Second spring; 24. Second piston; 241. Second groove; 242. Second radial through hole; 25. First spring seat; 26. First limiting screw; 27. Second spring seat; 28. Second limiting screw; 3. Plug; 4. Oil reservoir; 5. Electronic brake booster; 51. Housing. Detailed Implementation

[0019] The following specific embodiments illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification. Although the description of this utility model will be presented in conjunction with preferred embodiments, this does not mean that the features of this utility model are limited to this embodiment. On the contrary, the purpose of describing the utility model in conjunction with the embodiments is to cover other options or modifications that may be derived based on the claims of this utility model. To provide a deep understanding of this utility model, many specific details will be included in the following description. This utility model may also be implemented without using these details. Furthermore, to avoid confusion or obscuring the focus of this utility model, some specific details will be omitted in the description. It should be noted that, without conflict, the embodiments and features in the embodiments of this utility model can be combined with each other.

[0020] In the description of this embodiment, it should be noted that the terms "upper", "lower", "inner", "bottom", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship that the utility model product is usually placed in during use. They are only for the convenience of describing the utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the utility model.

[0021] The terms “first”, “second”, etc., are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0022] In the description of this embodiment, it should also be noted that, unless otherwise explicitly specified and limited, the terms "provided with," "set up," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this embodiment based on the specific circumstances.

[0023] On one hand, this application discloses a brake master cylinder. In this embodiment, the brake master cylinder is adapted to be mounted on an electronic brake booster.

[0024] Please see Figures 1-4As shown, a brake master cylinder includes a cylinder body 1 and a piston assembly 2. The piston assembly 2 is disposed within the inner cavity of the cylinder body 1. The cylinder body 1 is a cavity open at both ends, with a plug 3 at one end and the other end slidably connected to the piston assembly 2. An oil reservoir 4 communicating with the inner cavity of the cylinder body 1 is installed on the cylinder body 1. Compared to the traditional cylinder structure with one end sealed and one end open, the cavity structure with both ends open in this invention reduces the assembly difficulty of the piston assembly 2 and the difficulty of subsequent maintenance. Workers do not need to remove the brake master cylinder from the electronic brake booster; maintenance can be performed simply by removing the plug 3.

[0025] In this embodiment, a sealing ring is provided between the plug 3 and the cylinder 1.

[0026] The piston assembly 2 includes a first spring 21, a first piston 22, a second spring 23, and a second piston 24 arranged sequentially along the axial direction of the cylinder body 1. The first piston 22 and the second piston 24 are slidably connected to the inner cavity of the cylinder body 1. One end of the first piston 22 abuts against the plug 3 via the first spring 21, and the other end abuts against the second piston 24 via the second spring 23. The end of the second piston 24 away from the first piston 22 extends outside the cylinder body 1, suitable for abutting against the push rod on the electronic brake booster.

[0027] The cylinder block 1 is provided with a first oil supply port 11 and a second oil supply port 13 spaced apart. The first oil supply port 11 is located between the plug 3 and the first piston 22. The second oil supply port 13 is located between the first piston 22 and the second piston 24.

[0028] The outer peripheral wall of the first piston 22 near the end of the plug 3 is conical, so that the first piston 22 can be installed in the inner cavity of the cylinder body 1, and the hydraulic oil in the oil reservoir 4 can easily enter the inner cavity of the cylinder body 1, that is, enter the space between the plug 3 and the first piston 22. The outer peripheral wall of the first piston 22 away from the end of the plug 3 is cylindrical, and is slidably connected to the inner cavity of the cylinder body 1.

[0029] In this embodiment, the cylinder body 1 is provided with a first oil supply port 11, a first connecting hole 12, a second oil supply port 13, and a second connecting hole 14 sequentially along its axial direction. A first sealing ring is provided between the first oil supply port 11 and the first connecting hole 12, and the first sealing ring is adapted to cooperate with the outer peripheral wall of the first piston 22. A second sealing ring is provided between the first connecting hole 12 and the second oil supply port 13, and the second sealing ring is adapted to cooperate with the outer peripheral wall of the first piston 22. A third sealing ring is provided between the second oil supply port 13 and the second connecting hole 14, and the third sealing ring is adapted to cooperate with the outer peripheral wall of the second piston 24. A fourth sealing ring is provided on the side of the second connecting hole 14 away from the third sealing ring, and the fourth sealing ring is adapted to cooperate with the outer peripheral wall of the second piston 24. The first, second, third, and fourth sealing rings are all embedded in the inner cavity of the cylinder body 1.

[0030] Among them, the first sealing ring, the second sealing ring and the third sealing ring are all Y-type sealing rings.

[0031] The oil reservoir 4 is connected to the inner cavity of the cylinder 1 through the first connecting hole 12 and the second connecting hole 14. The first piston 22 is adapted to open or close the first connecting hole 12. The second piston 24 is adapted to open or close the second connecting hole 14.

[0032] Furthermore, to reduce the difficulty of spring assembly, please refer to... Figure 2 As shown, a first groove 221 is formed at the end of the first piston 22 near the first spring 21. One end of the first spring 21 is placed in the first groove 221 and abuts against the first piston 22, while the other end abuts against the plug 3 through the first spring seat 25. A first limiting screw 26 is provided on the inner ring of the first spring 21 to protect the first spring 21. The screw head of the first limiting screw 26 is placed in the first spring seat 25. The screw rod of the first limiting screw 26 passes through the first spring seat 25 and is threadedly connected to the first piston 22.

[0033] Please see Figure 2 As shown, the second piston 24 has a second groove 241 at one end near the second spring 23, and the other end extends outside the cylinder body 1. One end of the second spring 23 is placed in the second groove 241 and abuts against the second piston 24, while the other end abuts against the first piston 22 through the second spring seat 27. The inner ring of the second spring 23 is provided with a second limiting screw 28 for protecting the second spring 23. The screw head of the second limiting screw 28 is placed in the second spring seat 27. The screw rod of the second limiting screw 28 passes through the second spring seat 27 and is threadedly connected to the second piston 24.

[0034] In this embodiment, a first positioning protrusion adapted to the inner ring of the first spring 21 is provided in the first groove 221. One end of the first groove 221 is sleeved on the first positioning protrusion, and the other end is sleeved on the first spring seat 25. A second positioning protrusion adapted to the inner ring of the second spring 23 is provided in the second groove 241. One end of the second groove 241 is sleeved on the second positioning protrusion, and the other end is sleeved on the second spring seat 27.

[0035] Furthermore, first radial through holes 222 are respectively formed on the peripheral wall of the first groove 221. The first radial through holes 222 are distributed on the conical surface of the first piston 22 to reduce the difficulty of connecting the first connecting hole 12 to the first radial through holes 222. The first radial through holes 222 are distributed at equal angles with the axis of the first piston 22 as the center. In this embodiment, the angle between the conical surface of the first piston 22 and the central axis of the first piston 22 is 3° to 15°. Preferably, the angle between the conical surface of the first piston 22 and the central axis of the first piston 22 is 8°. Furthermore, second radial through holes 242 are respectively formed on the peripheral wall of the second groove 241. The second piston 24 includes a mating section, a conical section, and an extension section extending out of the cylinder body 1 connected sequentially along its axial direction. The mating section and the extension section are slidably connected to the cylinder body 1 to ensure smooth sliding of the second piston 24. The mating section and the conical section are transitioned by a rounded corner. The second radial through holes 242 are distributed on the conical section of the second piston 24 to reduce the difficulty of connecting the second connecting hole 14 to the second radial through holes 242. The second radial through holes 242 are distributed at equal angles around the axis of the second piston 24. In this embodiment, the conical surface of the conical section of the second piston 24 forms an angle of 3° to 8° with the central axis of the second piston 24. Preferably, the conical surface of the conical section of the second piston 24 forms an angle of 4° with the central axis of the second piston 24.

[0036] Furthermore, the inner cavity of the cylinder block 1 includes a first cavity, a second cavity, and a third cavity arranged sequentially along its axial direction. A first oil supply port 11 and a first connecting hole 12 are disposed in the first cavity, and the first piston 22 is slidably connected to the first cavity. A second oil supply port 13 is disposed in the second cavity, the inner diameter of which is larger than the outer diameter of both the first piston 22 and the second piston 24. A second connecting hole 14 is disposed in the third cavity, and the second piston 24 is slidably connected to the first cavity.

[0037] In this embodiment, please refer to Figure 3 As shown, a first annular groove 15 matching the first connecting hole 12 is provided in the first cavity to reduce the difficulty of connecting the first connecting hole 12 with the first radial through hole 222. A second annular groove 16 matching the second connecting hole 14 is provided in the third cavity to reduce the difficulty of connecting the second connecting hole 14 with the second radial through hole 242.

[0038] Furthermore, a connecting lug 17 is provided at the end of the cylinder body 1 away from the plug 3. In this embodiment, there are two connecting lugs 17, which are distributed on both sides of the second oil supply port 13.

[0039] The working principle of the brake master cylinder is as follows: When the piston assembly 2 moves axially toward the plug 3 along the cylinder body 1 under the push of the push rod of the electronic brake booster 5, the side wall of the first piston 22 closes the first connecting hole 12, and the side wall of the second piston 24 closes the second connecting hole 14. At this time, the space between the first piston 22 and the plug 3 is compressed, so that the hydraulic oil between the first piston 22 and the plug 3 is discharged to the outside of the cylinder body 1 through the first oil supply port 11; the space between the first piston 22 and the second piston 24 is compressed, so that the hydraulic oil between the first piston 22 and the second piston 24 is discharged to the outside of the cylinder body 1 through the second oil supply port 13, that is, the brake master cylinder performs the oil discharge action.

[0040] Once the push rod of the electronic brake booster 5 stops pushing, the first piston 22 and the second piston 24 return to their original positions under the action of the first spring 21 and the second spring 23, i.e., they move away from the plug 3. The side wall of the first piston 22 opens the first connecting hole 12, and the side wall of the second piston 24 opens the second connecting hole 14. At this time, the first connecting hole 12 is adapted to communicate with the first radial through hole 222, and the second connecting hole 14 is adapted to communicate with the second radial through hole 242. Therefore, the hydraulic oil in the oil reservoir 4 can enter the space between the first piston 22 and the plug 3 through the first connecting hole 12 and the first radial through hole 222 in sequence; the hydraulic oil in the oil reservoir 4 can also enter the space between the first piston 22 and the second piston 24 through the second connecting hole 14 and the second radial through hole 242 in sequence, i.e., the brake master cylinder performs an oil suction action.

[0041] On the other hand, this application discloses a braking system. Please refer to... Figure 5 As shown, the braking system includes an electronic brake booster 5 and a master cylinder. The cylinder body 1 is located outside the housing 51 of the electronic brake booster 5. The cylinder body 1 is mounted on the housing 51 via a connecting lug 17. The end of the second piston 24 furthest from the first piston 22 extends into the housing 51 and abuts against the push rod of the electronic brake booster 5.

[0042] The distribution of the connecting ear plate 17 will not affect the connection between the second oil supply port 13 and the external pipeline.

[0043] Among them, the electronic brake booster 5 is existing technology, so it will not be described in detail.

[0044] In summary, this invention reduces the assembly difficulty of the piston assembly and the difficulty of subsequent maintenance by designing the cylinder body as a cavity open at both ends. Workers can perform maintenance simply by removing the plug, without needing to remove the master cylinder from the electronic brake booster. The outer peripheral wall of the first piston near the plug is tapered, facilitating its installation within the cylinder cavity and allowing hydraulic oil from the reservoir to enter the cylinder cavity. The fit between the first annular groove and the tapered surface of the first piston reduces the difficulty of connecting the first connecting hole and the first radial through hole; similarly, the fit between the second annular groove and the tapered section of the second piston reduces the difficulty of connecting the second connecting hole and the second radial through hole.

[0045] The above embodiments are merely illustrative of the principles and effects of this utility model and are not intended to limit the scope of this utility model. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this utility model. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this utility model should still be covered by the claims of this utility model.

Claims

1. A brake master cylinder, suitable for mounting on an electronic brake booster, characterized in that, The brake master cylinder includes a cylinder body (1) and a piston assembly (2) disposed in the inner cavity of the cylinder body (1). The cylinder (1) is a cavity with openings at both ends. One end is provided with a plug (3), and the other end is slidably connected to the piston assembly (2). An oil can (4) is installed on the cylinder (1) and communicates with the inner cavity of the cylinder (1). The piston assembly (2) includes a first piston (22) and a second piston (24) that are slidably connected to the inner cavity of the cylinder (1); one end of the first piston (22) abuts against the plug (3) through a first spring (21), and the other end abuts against the second piston (24) through a second spring (23); the end of the second piston (24) away from the first piston (22) extends out of the cylinder (1); The outer peripheral wall of the first piston (22) near the end of the plug (3) is a conical surface; The cylinder body (1) is provided with a first oil supply port (11) located between the plug (3) and the first piston (22), and a second oil supply port (13) located between the first piston (22) and the second piston (24).

2. The brake master cylinder according to claim 1, characterized in that, The first piston (22) has a first groove (221) at one end near the first spring (21); one end of the first spring (21) is placed in the first groove (221) and abuts against the first piston (22), and the other end abuts against the plug (3) through the first spring seat (25); The inner ring of the first spring (21) is provided with a first limiting screw (26). The screw head of the first limiting screw (26) is placed inside the first spring seat (25), and its screw passes through the first spring seat (25) and is threadedly connected to the first piston (22). The second piston (24) has a second groove (241) at one end near the second spring (23), and the other end extends to the outside of the cylinder (1); one end of the second spring (23) is placed in the second groove (241) and abuts against the second piston (24), and the other end abuts against the first piston (22) through the second spring seat (27); The inner ring of the second spring (23) is provided with a second limiting screw (28). The screw head of the second limiting screw (28) is placed inside the second spring seat (27), and its screw passes through the second spring seat (27) and is threadedly connected to the second piston (24).

3. The brake master cylinder according to claim 2, characterized in that, The first groove (221) and the second groove (241) are respectively provided with a first radial through hole (222) and a second radial through hole (242). The first radial through hole (222) is distributed on the conical surface of the first piston (22); The second piston (24) includes a mating section, a conical section, and an extension section that are connected sequentially along its axial direction to the outside of the cylinder (1); the mating section and the extension section are slidably connected to the cylinder (1); The second radial through hole (242) is distributed on the conical section of the second piston (24).

4. The brake master cylinder according to claim 3, characterized in that, The first radial through holes (222) are distributed at equal angles with the axis of the first piston (22) as the center; The second radial through hole (242) is distributed at equal angles with the axis of the second piston (24) as the center.

5. The brake master cylinder according to claim 3, characterized in that, The angle between the conical surface of the first piston (22) and the central axis of the first piston (22) is 3° to 15°; The cone surface of the second piston (24) has an angle of 3° to 8° with the central axis of the second piston (24).

6. The brake master cylinder according to claim 1, characterized in that, The cylinder body (1) is provided with the first oil supply port (11), the first connecting hole (12), the second oil supply port (13), and the second connecting hole (14) in sequence along its axial direction. A first sealing ring is provided between the first oil supply port (11) and the first connecting hole (12); a second sealing ring is provided between the first connecting hole (12) and the second oil supply port (13); a third sealing ring is provided between the second oil supply port (13) and the second connecting hole (14); a fourth sealing ring is provided on the side of the second connecting hole (14) away from the third sealing ring; the first sealing ring, the second sealing ring, the third sealing ring and the fourth sealing ring are all embedded in the inner cavity of the cylinder body (1); The oil reservoir (4) is connected to the inner cavity of the cylinder (1) through the first connecting hole (12) and the second connecting hole (14); the first piston (22) is adapted to open or close the first connecting hole (12), and the second piston (24) is adapted to open or close the second connecting hole (14).

7. The brake master cylinder according to claim 6, characterized in that, The inner cavity of the cylinder (1) includes a first cavity, a second cavity and a third cavity arranged sequentially along its axial direction; The first oil supply port (11) and the first connecting hole (12) are disposed in the first cavity, and the first piston (22) is slidably connected to the first cavity; The second oil supply port (13) is located in the second cavity, and the inner diameter of the second cavity is larger than the outer diameter of the first piston (22) and the outer diameter of the second piston (24); The second connecting hole (14) is disposed in the third cavity, and the second piston (24) is slidably connected to the first cavity.

8. The brake master cylinder according to claim 7, characterized in that, The first cavity is provided with a first annular groove (15) that matches the first connecting hole (12); The third cavity is provided with a second annular groove (16) that matches the second connecting hole (14).

9. The brake master cylinder according to claim 7, characterized in that, The cylinder body (1) is provided with a connecting ear plate (17) at one end away from the plug (3), and the connecting ear plate (17) is distributed on both sides of the second oil supply port (13).

10. A braking system, characterized in that, Includes an electronic brake booster (5) and a brake master cylinder as described in any one of claims 1 to 9; The cylinder body (1) of the master cylinder is placed outside the housing (51) of the electronic brake booster (5) and is mounted on the housing (51); The second piston (24) of the brake master cylinder extends into the housing (51) at one end away from the first piston (22) and abuts against the push rod of the electronic brake booster (5).

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