Hydraulic brake master cylinder with vacuum buffer

Abstract

The hydraulic brake master cylinder with the vacuum buffer is composed of a base, a gland and an annular diaphragm which are fixed oppositely, and the outer edge of the diaphragm is fixed between the base and the gland in a sealed mode; the outer edge of the annular moving frame is in sealing connection with the inner edge of the diaphragm, and the center is connected with a pressing rod which is coaxially connected with the valve rod assembly through a base penetrating hole. One end of the control rod extends to the outer side of the gland and is connected with a valve bowl I; the outer side of the gland is connected with a protective cover; one end of the control rod is arranged in the protective cover; a spring I is arranged between the protective cover and the control rod, so that the valve bowl I closes the opening; the other end of the control rod is connected with a second valve bowl, and the movable frame is sealed with the second valve bowl when moving towards the control rod. A vacuumizing opening is formed in the side wall of the base. The structure can relieve brake pressure impact, reduce loss and pause of parts, and improve driving comfort and stability and safety of an automobile.

Description

Technical Field

[0001] This invention relates to the field of automotive braking technology, and more specifically to a hydraulic brake master cylinder with a vacuum damper. Background Technology

[0002] As a core power transmission component in automotive braking systems, the hydraulic brake master cylinder's performance directly determines the smoothness, safety, and ride comfort of the braking process. It is widely used in the braking systems of various gasoline and new energy vehicles. In existing technologies, the traditional hydraulic brake master cylinder structure has formed a relatively mature design system, referencing... Figure 1 As shown, it is mainly composed of cylinder M, piston assembly N, reservoir L, and auxiliary components such as seals and springs. The inner wall of cylinder M, the end face of piston assembly N, and the outlet interface of reservoir L form two key functional cavities through a sealing fit: the supply cavity R for storing and replenishing brake fluid, and the brake cavity S for establishing braking pressure and outputting brake fluid.

[0003] Under actual driving braking conditions, the working process of this traditional hydraulic brake master cylinder is as follows: When the driver depresses the brake pedal according to driving needs, the mechanical force of the brake pedal is transmitted to the piston assembly N through the transmission mechanism, causing the piston assembly N to move along the axis of the cylinder body M in the direction shown by arrow K1; during this process, the piston assembly N squeezes the brake fluid in the brake chamber S, causing the brake fluid pressure in the brake chamber S to rise rapidly. The high-pressure brake fluid is output to the brake wheel cylinder of the car through the oil outlet D opened on the cylinder body M, which in turn pushes the brake shoes to contact the brake drum (or brake disc) to generate friction, ultimately achieving the deceleration or stopping of the car; when the driver releases the brake pedal, the piston assembly N moves in the opposite direction under the action of the return spring, the pressure in the brake chamber S decreases, the brake fluid flows back to the brake master cylinder, the braking force is released, and the car returns to normal driving state.

[0004] However, the aforementioned traditional hydraulic brake master cylinder has the following problems in practical applications: it lacks any device to buffer braking impact. Specifically, when the driver applies the service brake, the braking force generated by the braking system acts directly on the car's wheels through the brake wheel cylinders, and is then transmitted to the vehicle body. Due to the lack of an effective buffering and absorption mechanism, the braking force generates a relatively strong impact load during transmission. This impact load not only causes a noticeable jerkiness during braking, severely affecting the comfort of the driver and passengers, but also causes the car's wheels, suspension system, transmission components, and other related parts to bear additional impact stress, accelerating wear and fatigue damage to the parts and shortening their service life. Long-term exposure to this impact condition may also lead to a decrease in the stability of the car's braking system, increasing safety hazards such as brake drift and longer braking distances, adversely affecting the vehicle's driving safety and reliability. Summary of the Invention

[0005] In view of the problems pointed out in the background art, the present invention proposes a hydraulic brake master cylinder with a vacuum buffer to solve the above-mentioned technical problems.

[0006] The technical solution of this invention is implemented as follows: A hydraulic brake master cylinder with a vacuum damper includes a cylinder body, a piston assembly connected inside the cylinder body, a brake chamber inside the cylinder body, and a fluid supply chamber and an oil outlet port communicating with the brake chamber on the cylinder body. The cylinder body is also connected to a valve stem assembly. When the pressure in the brake chamber increases, the hydraulic oil in the brake cylinder can push the valve stem assembly to move. It also includes a vacuum buffer, which includes a base and a cover with openings facing each other and fixedly connected to each other. An annular diaphragm is provided between the base and the cover, and the outer edge of the diaphragm is fixed between the base and the cover to form a seal. It also includes a ring-shaped movable frame, the outer edge of which is sealed and fixedly connected to the inner edge of the diaphragm, a pressure rod connected to the center of the movable frame, and a through hole for the pressure rod to extend out on the side wall of the base; The side wall of the gland is provided with an opening coaxial with the pressure rod. An axially movable control rod is connected inside the opening. One end of the control rod extends to the outside of the gland and is connected to a valve cup. A cover is connected to the outer wall of the gland. One end of the control rod is located inside the cover. A spring is provided between the control rod and the cover. The spring applies an axial force to the control rod, causing the valve cup to close the opening. A communication port is provided on the side wall of the cover. The other end of the control lever is connected to valve cup two. When the moving frame moves toward the control lever, the inner edge of the moving frame can abut against valve cup two to form a seal. The base has a vacuum port on its side wall; The pressure rod and valve stem assembly are coaxially connected.

[0007] The invention is further configured such that the outer wall of the cylinder is provided with a mounting hole, the bottom of the mounting hole is provided with a connecting hole communicating with the brake chamber, the diameter of the connecting hole being smaller than the diameter of the mounting hole; the valve stem assembly includes a valve stem, the valve stem including a thicker section adapted to the mounting hole and a thinner section extending through the connecting hole into the brake chamber, an O-ring is provided between the thicker section and the mounting hole, a cup is provided between the thinner section and the mounting hole, and a pressure rod is connected to the thicker section of the valve stem.

[0008] The present invention is further configured such that the base is fixedly connected to the cylinder body, and an annular sealing ring is provided between the base and the cylinder body, with the through hole and the mounting hole located inside the sealing ring.

[0009] The present invention is further configured such that the cover is provided with a filter element for filtering the air entering through the communication port.

[0010] The invention is further configured such that a limiting block is provided inside the braking chamber, which can limit the stroke of the thinner section of the valve stem into the braking chamber.

[0011] The invention is further configured such that the pressure rod is coaxially arranged with the movable frame, and the pressure rod is fixedly connected to the movable frame through a connecting rib.

[0012] The present invention is further configured such that the first spring is coaxially arranged with the control rod, and one end of the control rod is provided with a spring seat connected to the first spring.

[0013] The present invention is further configured such that the diameter of the thinner segment of the valve stem is smaller than the diameter of the connecting hole.

[0014] By adopting the above technical solution, the beneficial effects of the present invention are as follows: The hydraulic brake master cylinder with vacuum damper provided by this invention is characterized by a vacuum damper designed on one side of the brake master cylinder. This reduces the impact of the pressure generated during vehicle braking on the wheels and body, decreases wear on vehicle parts, reduces the jerking sensation caused by impact, improves the comfort of passengers, and enhances the vehicle's stability and safety.

[0015] The present invention provides a hydraulic brake master cylinder with vacuum damper, which alleviates the impact on the car during braking, reduces damage to the car's mechanical parts, improves the car's stability, enhances the comfort of the driver and passengers, and improves the car's safety and service life. It is a creative design. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the existing technology.

[0018] Figure 2 This is a schematic diagram of the structure of the present invention.

[0019] Figure 3 For the present invention Figure 2 Enlarged view of part A in the image.

[0020] Figure 4 This is a schematic diagram of the structure of the vacuum buffer of the present invention.

[0021] Figure 5 This is a schematic diagram of the valve stem assembly of the present invention.

[0022] The following are the labels in the attached diagram: Cylinder 1, Piston Assembly 2, Braking Chamber 3, Liquid Supply Chamber 4, Oil Outlet 5, Base 6, Pressure Cap 7, Diaphragm 8, Moving Frame 9, Pressure Rod 10, Perforation 11, Opening 12, Control Rod 13, Valve Cup 1 14, Protective Cover 15, Spring 1 16, Connecting Port 17, Valve Cup 2 18, Vacuum Port 19, Mounting Hole 20, Connecting Hole 21, Valve Stem 22, Thicker Section 23, Thinner Section 24, O-ring 25, Leather Cup 26, Sealing Ring 27, Filter Element 28, Limiting Block 29, Connecting Rib 30, Spring Seat 31. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] For reference as follows Figures 1-5 The present invention will be described as follows: Example: A hydraulic brake master cylinder with vacuum damper includes a cylinder body 1, which serves as the load-bearing base for the entire brake master cylinder and provides installation, positioning, and movement space for internal components.

[0025] The cylinder body 1 is connected to a piston assembly 2 (connected inside the cylinder body 1, which can reciprocate along the axis of the cylinder body 1. During braking, the piston assembly 2 is compressed towards the bottom of the cylinder body 1, closing the communication channel between the fluid supply chamber 4 and the brake chamber 3, so that the brake chamber 3 forms a closed space, thereby establishing high pressure; when the brake is released, the piston assembly 2 returns to its original position, the fluid supply chamber 4 and the brake chamber 3 are reconnected, and brake fluid is replenished). The cylinder body 1 is provided with a brake chamber 3 (the core cavity for establishing hydraulic oil pressure. When the piston assembly 2 reciprocates in the cavity, it can change the volume of the cavity to adjust the hydraulic oil pressure). The cylinder body 1 is also provided with a fluid supply chamber 4 (connected to the brake chamber 3, used to store brake fluid and replenish hydraulic oil to the brake chamber 3 to ensure sufficient hydraulic oil supply during braking) and an oil outlet 5 (connected to the brake chamber 3, serving as the output channel of high-pressure hydraulic oil, directly connected to the car brake wheel cylinder to realize the transmission of braking force).

[0026] A valve stem assembly is also connected to the cylinder body 1. When the pressure inside the brake chamber 3 increases, the hydraulic oil inside the brake chamber 3 can push the valve stem assembly to move. The valve stem assembly is connected to the cylinder body 1, and its movement is controlled by the hydraulic oil pressure inside the brake chamber 3. When the pressure inside the brake chamber 3 rises, the hydraulic oil generates an axial thrust on the valve stem assembly, pushing the valve stem assembly to move in the direction of the vacuum buffer (K2 direction), serving as a transmission medium between the pressure of the brake chamber 3 and the action of the vacuum buffer.

[0027] It also includes a vacuum buffer, which is the core component for achieving the buffering function. It absorbs braking shocks through pressure changes in the vacuum cavity.

[0028] The vacuum buffer includes a base 6 and a cover 7 with openings facing each other and fixedly connected to each other, forming the outer shell of the vacuum buffer; one side of the base 6 is fitted with the cylinder 1, and one side of the cover 7 is the external control end. The two are fixed by bolts to ensure overall sealing.

[0029] An annular diaphragm 8 is provided between the base 6 and the pressure cap 7. The diaphragm 8 is made of an elastic sealing material (such as nitrile rubber). The outer edge of the diaphragm 8 is fixed between the base 6 and the pressure cap 7 to form a seal. The diaphragm 8 divides the space enclosed by the base 6 and the pressure cap 7 into two independent cavities (vacuum cavity A and vacuum cavity B).

[0030] It also includes an annular movable frame 9, the outer edge of the movable frame 9 being sealed and fixedly connected to the inner edge of the diaphragm 8, and the movable frame 9 being able to drive the diaphragm 8 to extend and retract axially.

[0031] The center of the movable frame 9 is connected to a pressure rod 10, and the side wall of the base 6 is provided with a through hole 11 for the pressure rod 10 to extend out.

[0032] The pressure rod 10 is coaxially connected to the valve stem assembly. Hydraulic oil pushes the valve stem assembly to move, the valve stem assembly pushes the pressure rod 10 to move, and the pressure rod 10 drives the moving frame 9 and the diaphragm 8 to move.

[0033] The side wall of the pressure cap 7 is provided with an opening 12 coaxial with the pressure rod 10. A control rod 13 that can move axially is coaxially connected in the opening 12. One end of the control rod 13 extends to the outside of the pressure cap 7.

[0034] One end of the control lever 13 is connected to a valve cup 14 (the valve cup 14 is made of elastic material and fits against the outer wall of the pressure cap 7 to control the opening and closing of the opening 12).

[0035] A cover 15 is fixedly connected to the outer wall of the pressure cover 7. One end of the control rod 13 is located inside the cover 15. A spring 16 is provided between the control rod 13 and the cover 15. The spring 16 is sleeved on the control rod 13, and its two ends abut against the inner wall of the cover 15 and the control rod 13, respectively. The spring 16 applies an axial elastic force to the control rod 13. Through the elastic force, the valve cup 14 is always pressed against the outer wall of the pressure cover 7, and the opening 12 is closed under normal conditions. A communication port 17 is provided on the side wall of the cover 15 to communicate with the outside, so as to ensure that the internal pressure of the cover 15 is the same as that of the outside atmospheric pressure.

[0036] The other end of the control rod 13 is connected to the valve cup 18. When the moving frame 9 moves toward the control rod 13, the inner edge of the moving frame 9 can fit with the valve cup 18 to form a seal, thereby separating the vacuum cavity A from the vacuum cavity B.

[0037] The base 6 has a vacuum port 19 on its side wall that communicates with its interior. The vacuum port 19 is located on the side wall of the base 6 and communicates with the interior of the base 6 (vacuum cavity A). It is connected to the vehicle vacuum generator through a pipe. After the car is started, the vacuum generator evacuates the vacuum cavities A and B through the vacuum port 19 until the set vacuum level is reached. If the vacuum level is insufficient, it will automatically replenish the vacuum to ensure that the buffer always maintains a stable vacuum state.

[0038] The buffering function of this technical solution is achieved through four stages: "braking pressure triggering - vacuum cavity separation - differential pressure buffering - reset balance". The specific process is as follows: (a) Initial state (non-braking condition) 1. The piston assembly 2 is in the reset position, the supply chamber 4 and the brake chamber 3 are in communication, the hydraulic oil pressure in the brake chamber 3 is the same as that in the supply chamber 4 (normal pressure), and the valve stem assembly does not move axially; 2. The vacuum generator has evacuated vacuum chambers A and B through vacuum port 19, and the pressure in the two chambers is the same (maintaining the set vacuum level). 3. The elastic force of spring 16 causes valve cup 14 to press against the outer wall of pressure cover 7, closing the opening 12, and isolating vacuum cavity B from the outside atmosphere; the moving frame 9 does not contact valve cup 18, and vacuum cavities A and B are connected through the middle hole of the moving frame 9, maintaining the whole in a vacuum state.

[0039] (II) Braking Triggering and Vacuum Separation Stage (Initial Braking) 1. When the driver presses the brake pedal, the piston assembly 2 compresses towards the bottom of the cylinder 1, closing the connection between the fluid supply chamber 4 and the brake chamber 3, and the hydraulic oil pressure in the brake chamber 3 rises rapidly. 2. High-pressure hydraulic oil generates axial thrust on the valve stem assembly, pushing the valve stem assembly to move in the K2 direction (vacuum buffer direction), and the valve stem assembly drives the pressure rod 10 to move synchronously; 3. The pressure rod 10 pushes the moving frame 9 to move towards the control rod 13, and the diaphragm 8 expands and contracts with the moving frame 9. When the moving frame 9 moves to the point where its inner edge fits against the valve bowl 18, the two form a seal, separating the vacuum cavities A and B. At this time, the two cavities still maintain the initial vacuum level (consistent pressure).

[0040] (III) Differential Pressure Buffering Phase (Peak Braking Pressure Period) 1. As the pressure inside the brake chamber 3 continues to rise, the valve stem assembly continues to push the pressure rod 10 and the moving frame 9 to move. The moving frame 9 drives the control rod 13 to overcome the elastic force of the spring 16 and move to the outside of the pressure cover 7 through the valve cup 2 18. 2. The control lever 13 moves to separate the valve bowl 14 from the outer wall of the pressure cover 7, the opening 12 opens, and the vacuum cavity B is connected to the outside atmosphere through the opening 12 and the connecting port 17 of the cover 15. The pressure in the vacuum cavity B rises rapidly from a vacuum state to atmospheric pressure. 3. At this time, vacuum cavity A still maintains a vacuum state, and a significant pressure difference (the difference between atmospheric pressure and vacuum degree) is formed between vacuum cavity A and B. This pressure difference generates a reverse thrust on the moving frame 9 (opposite to the pushing direction of the pressure rod 10). 4. The reverse thrust partially offsets the hydraulic thrust transmitted by the valve stem assembly, slowing down the rate of pressure rise in the brake chamber 3, thereby reducing the impact of brake fluid pressure transmission to the brake wheel cylinder, achieving a buffering effect, and preventing the wheel and body from bearing instantaneous impact loads.

[0041] (iv) Reset and balance phase (braking stabilization or release period) 1. When the pressure in the brake chamber 3 tends to stabilize (or the driver releases the brake pedal and the pressure in the brake chamber 3 decreases), the thrust of the valve stem assembly weakens; 2. The pressure difference between vacuum chambers A and B pushes the moving frame 9 to move in the opposite direction to K3 (valve stem assembly direction), thereby causing the pressure rod 10 and the valve stem assembly to reset; 3. The movable frame 9 separates from the valve bowl 18, the vacuum chambers A and B are reconnected, and the pressure inside the chambers is rebalanced to a vacuum state; at the same time, the control rod 13 is reset under the elastic force of the spring 16, the valve bowl 14 presses the outer wall of the cover 7 again, and the opening 12 is closed. 4. The piston assembly 2 is reset, the fluid supply chamber 4 and the brake chamber 3 are reconnected, the braking system returns to its initial state, and waits for the next braking operation.

[0042] Compared to traditional hydraulic brake master cylinders without buffering function, this solution achieves the following core improvements through the design of a vacuum damper: (i) Effectively reduces braking shock and improves driving stability Traditional brake master cylinders transmit braking pressure directly to the wheels, which can easily generate impact loads. This solution uses the pressure difference in the vacuum chamber to counteract part of the peak braking pressure, slow down the pressure transmission rate, and gradually apply braking force to the wheels, avoiding obvious jerking of the vehicle body and improving the smoothness of the braking process.

[0043] (ii) Reduce component wear and extend service life Braking impact loads can accelerate fatigue damage to wheels, suspension, and transmission components. This solution reduces impact stress through buffering, decreases instantaneous stress on components, lowers the risk of wear and fatigue failure, and extends the service life of the braking system and related body components.

[0044] (III) Ensure braking safety and optimize driving experience The buffering process does not affect the final establishment of braking pressure, ensuring that the braking distance meets safety requirements; at the same time, the elimination of jerking sensation improves the comfort of the driver and passengers, avoiding discomfort caused by impact, especially under frequent braking conditions (such as driving on urban roads), the effect is more significant.

[0045] (iv) High structural reliability and strong adaptability The vacuum buffer adopts a diaphragm seal and a two-way valve cup control structure, which has good sealing performance and maintains a stable vacuum state. The overall structure is compact and can be directly integrated into the cylinder body of the existing brake master cylinder without major modifications to the main structure of the master cylinder, making it suitable for the braking system requirements of various fuel vehicles and new energy vehicles.

[0046] The outer side wall of the cylinder 1 is provided with a mounting hole 20, and the bottom of the mounting hole 20 is provided with a connecting hole 21 that communicates with the brake chamber 3. The mounting hole 20 and the connecting hole 21 are coaxial, and the diameter of the connecting hole 21 is smaller than the diameter of the mounting hole 20.

[0047] The valve stem assembly includes a valve stem 22, which includes a thicker section 23 adapted to the mounting hole 20 and a thinner section 24 extending into the brake chamber 3 through the connecting hole 21. The diameter of the thinner section 24 of the valve stem 22 is smaller than the diameter of the connecting hole 21 (to provide a pressure transmission channel for hydraulic oil). An O-ring 25 is provided between the thicker section 23 and the mounting hole 20, and a cup 26 is provided between the thinner section 24 and the mounting hole 20. The pressure rod 10 is connected to the thicker section 23 of the valve stem 22.

[0048] The valve stem 22 can move smoothly along the mounting hole 20 axially.

[0049] The connecting hole 21 serves as a pressure transmission channel between the brake chamber 3 and the valve stem assembly. When the hydraulic oil pressure in the brake chamber 3 increases, the high-pressure hydraulic oil can pass through the gap between the connecting hole 21 and the thinner section 24 and act on the end face of the valve stem 22 (the stepped surface between the thicker section 23 and the thinner section 24), generating an axial force that pushes the valve stem 22 to move in the direction of the vacuum buffer, thereby realizing the transmission of braking pressure to the vacuum buffer.

[0050] The valve stem 22 and its subdivided thicker section 23 and thinner section 24, together with the O-ring 25 and the cup 26, constitute an integrated valve stem assembly that combines pressure sensing, power transmission and sealing functions.

[0051] The lip of the leather cup 26 faces the brake chamber 3, which can further enhance the sealing effect and prevent hydraulic oil leakage.

[0052] One side of the base 6 is fixedly connected to the cylinder body 1. An annular sealing ring 27 is provided between the base 6 and the cylinder body 1. The sealing ring 27 needs to be installed between the contact surfaces of the base 6 and the cylinder body 1. The through hole 11 and the mounting hole 20 are both located inside the sealing ring 27. The through hole 11, the mounting hole 20, and the sealing ring 27 are coaxial. The sealing ring 27 plays a sealing role between the base 6 and the cylinder body 1.

[0053] The sealing ring 27 can block the connection between the vacuum buffer (inside the base 6) and the outside atmosphere, preventing outside air from entering the vacuum cavity A through the connection gap between the base 6 and the cylinder 1, ensuring the vacuum state of the vacuum cavity A is stable, and avoiding the weakening of the buffering effect due to the decrease in vacuum degree.

[0054] The cover 15 is equipped with a filter element 28 that filters the air entering through the connection port 17. The outside air must first enter the filter element 28 through the connection port 17, be filtered by the filter element 28, and then enter the interior of the cover 15, and finally enter the vacuum chamber B through the opening 12. The filtered air can prevent dust, particles and other impurities from adhering to the sealing surface of the valve bowl 14 or entering the vacuum chamber B, thus preventing sealing failure or wear of the diaphragm 8.

[0055] A limiting block 29 is provided inside the brake chamber 3. The limiting block 29 can limit the stroke of the thinner section 24 of the valve stem 22 into the brake chamber 3. It limits the maximum stroke of the thinner section 24 of the valve stem 22 into the brake chamber 3, preventing the thinner section 24 from extending too far and colliding with the piston assembly 2 or the inner wall of the brake chamber 3. At the same time, it avoids damage to the piston cup 26 due to excessive stretching, ensuring the safety and stability of the valve stem assembly movement.

[0056] The pressure rod 10 is coaxially arranged with the movable frame 9, and the pressure rod 10 is fixedly connected to the movable frame 9 through the connecting rib 30. The gap between the connecting ribs 30 can serve as a connecting channel between vacuum cavities A and B (in the initial state), ensuring that the two cavities can reach the set vacuum level synchronously during evacuation, without the need for additional vent holes, thus simplifying the structural design.

[0057] Spring 16 is coaxially mounted with control lever 13, and one end of control lever 13 is provided with spring seat 31 connected to spring 16. Spring seat 31 is a key component for achieving stable installation of spring 16 and uniform transmission of elastic force.

[0058] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A hydraulic brake master cylinder with a vacuum damper, comprising a cylinder body, a piston assembly connected inside the cylinder body, a brake chamber provided inside the cylinder body, and a fluid supply chamber and an oil outlet port communicating with the brake chamber on the cylinder body, characterized in that: The cylinder body is also connected to a valve stem assembly. When the pressure in the brake chamber increases, the hydraulic oil in the brake cylinder can push the valve stem assembly to move. It also includes a vacuum buffer, which includes a base and a cover with openings facing each other and fixedly connected to each other. An annular diaphragm is provided between the base and the cover, and the outer edge of the diaphragm is fixed between the base and the cover to form a seal. It also includes a ring-shaped movable frame, the outer edge of which is sealed and fixedly connected to the inner edge of the diaphragm, a pressure rod connected to the center of the movable frame, and a through hole for the pressure rod to extend out on the side wall of the base; The side wall of the gland is provided with an opening coaxial with the pressure rod. An axially movable control rod is connected inside the opening. One end of the control rod extends to the outside of the gland and is connected to a valve cup. A cover is connected to the outer wall of the gland. One end of the control rod is located inside the cover. A spring is provided between the control rod and the cover. The spring applies an axial force to the control rod, causing the valve cup to close the opening. A communication port is provided on the side wall of the cover. The other end of the control lever is connected to valve cup two. When the moving frame moves toward the control lever, the inner edge of the moving frame can abut against valve cup two to form a seal. The base has a vacuum port on its side wall; The pressure rod and valve stem assembly are coaxially connected.

2. The hydraulic brake master cylinder with vacuum buffer according to claim 1, characterized in that: The cylinder body has an installation hole on its outer side wall, and a connecting hole at the bottom of the installation hole communicates with the brake chamber. The diameter of the connecting hole is smaller than the diameter of the installation hole. The valve stem assembly includes a valve stem, which includes a thicker section that fits the installation hole and a thinner section that extends through the connecting hole into the brake chamber. An O-ring is provided between the thicker section and the installation hole, and a cup is provided between the thinner section and the installation hole. The pressure rod is connected to the thicker section of the valve stem.

3. A hydraulic brake master cylinder with vacuum buffer according to claim 2, characterized in that: The base is fixedly connected to the cylinder body, and an annular sealing ring is provided between the base and the cylinder body. The through hole and the mounting hole are both located inside the sealing ring.

4. A hydraulic brake master cylinder with vacuum buffer according to claim 3, characterized in that: The cover is equipped with a filter element that filters the air entering through the connection port.

5. A hydraulic brake master cylinder with vacuum buffer according to claim 3, characterized in that: The brake chamber is equipped with a limiting block, which can limit the travel of the thinner section of the valve stem into the brake chamber.

6. A hydraulic brake master cylinder with vacuum buffer according to claim 1, characterized in that: The pressure rod is coaxially arranged with the movable frame, and the pressure rod is fixedly connected to the movable frame through connecting ribs.

7. A hydraulic brake master cylinder with vacuum buffer according to claim 1, characterized in that: The spring is coaxially arranged with the control rod, and one end of the control rod is provided with a spring seat connected to the spring.

8. A hydraulic brake master cylinder with vacuum buffer according to claim 2, characterized in that: The diameter of the thinner section of the valve stem is smaller than the diameter of the connecting hole.

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