Pressure relief structure of brake valve

Abstract

The application provides a pressure relief structure of a brake valve and belongs to the technical field of brake valves. The technical problem of unstable pressure relief of an existing power brake valve is solved. The pressure relief structure of the brake valve comprises a confluence section on the end face of a balance piston close to a main piston, oil drain holes on the outer circumferential surface of the balance piston, and a one-way assembly between the balance piston and the main piston and blocking the communication state of the confluence section and an oil inlet hole. The oil drain holes are several and all communicate with the confluence section. An active rod penetrating the balance piston is slidably connected in the balance piston. One end of the active rod is always located in the confluence section and can move axially towards the one-way assembly and open the one-way assembly. The oil drain holes are several and the ports communicating the oil drain holes and the confluence section are arranged in the circumferential direction of the active rod. The brake valve is beneficial to ensure the stability of the pressure relief state.

Description

Technical Field

[0001] The invention belongs to the technical field of brake valves and relates to a pressure relief structure of a brake valve. Background Art

[0002] Automobile brake valves are divided into pneumatic brake valves and hydraulic brake valves. The proper functioning of brake valves is crucial for vehicle braking, providing technical support for smooth braking. The development of this technology is of vital importance to both automobile manufacturing and road traffic safety.

[0003] For example, Chinese patent application number CN200920306571.2 discloses a fully hydraulic brake valve, which includes a valve body with an inner cavity, an oil inlet port connected to the oil tank, and a working oil port connected to the brake. A piston assembly that controls the flow of oil and a linkage piston connected to the brake pedal are installed within the valve body. When the driver presses the brake pedal, the linkage piston drives the piston assembly to move, achieving braking. To make braking easier and ensure sufficient braking force, a brake valve with power assist is designed. This valve is typically equipped with a pressurizing mechanism that pressurizes the working area during braking and releases the pressure to reset the valve when braking is complete.

[0004] However, existing brake valves are often susceptible to interference when triggering pressure relief, making it difficult for the pressure relief valve to maintain a stable position and resulting in poor pressure relief stability. To address this issue, those skilled in the art can consider: 1. arranging the pressure relief structure in a fixed position relative to the piston; 2. Designing components surrounding the pressure relief structure to maintain a stable position relative to the pressure relief structure to prevent component position changes from affecting the pressure relief structure itself and causing unstable pressure relief. Summary of the Invention

[0005] In view of the above problems existing in the prior art, the present invention provides a brake valve pressure relief structure. The technical problem to be solved by the present invention is that the pressure relief of the existing power-assisted brake valve is unstable.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A pressure relief structure of a brake valve, the brake valve includes a valve body with an oil inlet hole, and a main piston and a balance piston are slidably connected in the valve body, which are in contact with each other. The pressure relief structure is characterized in that it includes a confluence section located on the end face of the balance piston close to the main piston, an oil drain hole located on the outer peripheral surface of the balance piston, and a one-way component located between the balance piston and the main piston and blocking the connection between the confluence section and the oil inlet hole. There are several oil drain holes and they are all connected to the confluence section. A movable rod that passes through the balance piston is slidably connected in the balance piston, one end of the movable rod is always located in the confluence section and can move axially toward the one-way component and push the one-way component open. There are several oil drain holes and the ports connecting the oil drain holes to the confluence section are arranged at intervals around the circumference of the movable rod.

[0008] After the pressure replenishment is completed, the pressure in the working chamber is completed, and as the balancing piston continues to move, the pressure will gradually increase, and one end of the movable rod is always in the position where it is needed. When the cam is opened, the cam will release the oil from the oil pump, and the cam will release the oil from the oil pump, so that the cam will be in a good condition and will not stagnate or the cam will wither.

[0009] In the aforementioned brake valve pressure relief structure, the oil drain hole is arranged radially from the outside to the inside of the balancing piston, tilted toward the side where the one-way assembly is located. This allows the fluid flowing through the oil drain hole to flow at a velocity consistent with the orientation of the movable rod, thereby reducing direct impact of the fluid passing through the oil drain hole on the movable rod and, consequently, minimizing the likelihood of the movable rod shaking and affecting the opening state of the one-way assembly.

[0010] In the aforementioned brake valve pressure relief structure, the plurality of oil drain holes communicating with the ports of the confluence section are evenly spaced around the circumference of the movable rod. This facilitates a more even distribution of the impact of the fluid passing through the oil drain holes on the movable rod, further ensuring the stability of the movable rod and the one-way assembly in the open state.

[0011] In the above-mentioned brake valve pressure relief structure, the outer periphery of the middle section of the movable rod or the outer periphery of the other end of the movable rod is sealed with the balance piston, which ensures that the pressure difference between the two end surfaces of the movable rod is stable and continuous, and improves the reliability of the sliding triggering of the movable rod.

[0012] In the aforementioned brake valve pressure relief structure, the end surface of the balancing piston includes a boss-like connection portion, the confluence section is located on the end surface of the connection portion, and the end surface of the main piston includes a positioning groove, the bottom of which communicates with the oil inlet hole. The connection portion is positioned and embedded in the positioning groove and seals against the circumferential inner wall of the positioning groove. This specific cooperation between the connection portion and the positioning groove ensures that the position of the balancing piston end is fully constrained by the inner wall of the positioning groove, while also preventing fluid from the oil supply chamber from intruding into the other side of the one-way assembly, ensuring the blocking and sealing effect of the one-way assembly and facilitating pressure relief stability.

[0013] In the pressure relief structure of the brake valve described above, an annular support member is fixedly connected to the inner cavity side wall of the valve body, and one end of the main piston that abuts the balance piston is positioned and inserted into the support member. By fixing the annular support member to the inner wall of the valve body, the ends of the main piston and the balance piston that abut against each other are slidably fitted into the support member. At the same time, the end of the balance piston is inserted into the main piston, and the one-way assembly is arranged at the junction of the main piston and the balance piston. In this way, the end of the balance piston is positioned in the main piston, and this end of the main piston is constrained by the fixed support member. This makes the position of the one-way assembly more stable and will not be affected by the shaking of the balance piston, ensuring that the working state of the one-way assembly is not disturbed, thereby achieving stable pressure relief.

[0014] In the above brake valve pressure relief structure, the one-way assembly is positioned opposite or approximately opposite to the support member along the radial direction of the main piston, thereby further ensuring that the one-way assembly is arranged in an area fully constrained by the support member, thereby enhancing the stability of the one-way assembly's working state.

[0015] In the aforementioned brake valve pressure relief structure, the one-way assembly includes a compression spring and a spherical valve block. The compression spring is arranged axially along the active rod and located within the primary piston. The two ends of the compression spring act on the primary piston and the valve block, respectively. The valve block is located at the interface between the primary piston and the balancing piston, abutting against the balancing piston and sealing the confluence section. This ensures a sealing effect while allowing the active rod to effectively lift the valve block during pressure relief. After pressure relief is complete, the active rod returns to its original position, and the valve block is stably reset under the action of the compression spring.

[0016] In the aforementioned brake valve pressure relief structure, the balancing piston further comprises a balancing flow channel. The two ports of the balancing flow channel are located on the outer peripheral surface of the balancing piston and on the side of the balancing piston remote from the main piston, respectively. A one-way sealing member is connected to the side of the balancing piston remote from the main piston, allowing only the fluid in the balancing flow channel to flow out. The other end of the movable rod is inserted into the one-way sealing member. This allows the high-pressure fluid generated by compression in the oil supply chamber to enter the working chamber through the balancing flow channel, generating a pressure-compensating effect and thereby increasing the brake operating pressure. The one-way sealing member prevents direct pressure relief in the working chamber, while also constraining the movable rod to ensure its stable position.

[0017] In the aforementioned brake valve pressure relief structure, the one-way sealing member comprises an annular valve member, a spring member, and a support disk fixed relative to the balancing piston. The annular valve member is sleeved around the outer periphery of the movable rod and seals with the movable rod. The two ends of the spring member act on the annular valve member and the support disk, respectively, ensuring that the annular valve member always tends to seal the balancing flow channel. The end of the movable rod abuts against the support disk. In this way, the annular valve member prevents fluid from leaking from the one-way sealing member, while the movable rod provides positioning for the annular valve member, ensuring a stable opening and closing state of the one-way sealing member. The support disk also limits the travel and position of the movable rod, thereby facilitating improved stability of the movable rod's position.

[0018] In the aforementioned brake valve pressure relief structure, the movable rod comprises a connected push rod section and a connecting section. The push rod section has a smaller diameter than the connecting section, allowing it to abut against the valve block. The annular valve member is permanently positioned around the outer circumference of the connecting section. This abutment of the smaller push rod section against the valve block ensures a sufficient flow cross-section in the confluence section, reduces the impact force exerted on the movable rod by the fluid in the oil drain hole, reduces the likelihood of the movable rod shaking, and improves pressure relief stability.

[0019] Compared with the prior art, the advantages of the present invention are as follows:

[0020] The pressure relief structure of the above-mentioned brake valve is arranged by circumferentially spacing a plurality of oil drain holes connected to the port of the confluence section. When the oil supply chamber is pressure-relieved, the fluid can flow through the plurality of oil drain holes arranged circumferentially around the movable rod, so that the pressurized fluid in different oil drain holes disperses the impact force on the movable rod that is pressed against the one-way component from all sides, reducing the phenomenon of the movable rod being shaken or even deviated by the impact, thereby making the opening state and position of the one-way component more stable, thereby ensuring stable pressure relief. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic cross-sectional structural diagram of the confluence section in the closed state of this embodiment.

[0022] Figure 2 yes Figure 1 Enlarged view of part A in .

[0023] Figure 3 It is a schematic cross-sectional structural diagram of the confluence section in the open state of this embodiment.

[0024] Figure 4 yes Figure 3 Enlarged view of part B in .

[0025] Figure 5 yes Figure 4 Enlarged view of part C in .

[0026] Figure 6 It is a schematic diagram of the three-dimensional structure of this embodiment.

[0027] In the figure, 1, valve body; 11, oil inlet hole; 12, working oil hole;

[0028] 2. Balancing piston; 21. Converging section; 22. Connecting portion; 23. Balancing flow channel; 24. Oil drain hole;

[0029] 3. Main piston; 31. Positioning groove;

[0030] 4. Working chamber; 5. Oil supply chamber; 6. Support member;

[0031] 7. One-way assembly; 71. Compression spring; 72. Valve block;

[0032] 8. Movable rod; 81. Top rod section; 82. Connecting section;

[0033] 9. One-way blocking member; 91. Annular valve member; 911. Valve plate; 912. Sealing ring; 9121. Sealing lip; 9122. Annular boss; 913. Spring washer; 92. Spring member; 93. Support plate;

[0034] 10. Spring seat; 20. Pedal connecting rod assembly; 30. Control oil hole; 40. Oil return hole; 50. Return spring; 60. Spring base; 70. Guide rod. DETAILED DESCRIPTION

[0035] The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical solutions of the present invention, but the present invention is not limited to these embodiments.

[0036] like Figure 1As shown, in the pressure relief structure of the brake valve, the brake valve includes a valve body 1 with an oil inlet hole 11 and a working oil hole 12, and a main piston 3 and a balancing piston 2 are slidably connected in the valve body 1. The outer diameter of the main piston 3 is larger than the outer diameter of the balancing piston 2, that is, the radial size of the inner cavity of the valve body 1 in the sliding area of ​​the main piston 3 is larger than the radial size of the inner cavity of the valve body 1 in the sliding area of ​​the balancing piston 2. When braking, a working chamber 4 connected to the working oil hole 12 is formed between the end surface of the balancing piston 2 away from the main piston 3 and the inner wall of the valve body 1. The outer periphery of the balancing piston 2 can form an oil supply chamber 5 that can compensate for the pressure of the working chamber 4 through a sealing structure with the inner wall of the valve body 1. The volume of the oil supply chamber 5 and the working chamber 4 can change with the sliding of the balancing piston 2; the oil inlet hole 11 can be connected to the oil cup to supply oil for the brake valve. 12 is connected to the brake to output oil pressure to control braking. The main piston 3 and the balance piston 2 arranged in the valve body 1 can be triggered by the driver stepping on the pedal connecting rod assembly 20 to cause oil to enter the control oil hole 30 and act on the end face of the main piston 3. The main piston 3 is driven by the oil pressure to drive the balance piston 2 to slide. The return oil hole 40 is used to discharge the fluid acting on the end face of the main piston 2 after the braking is completed. The increased oil pressure in the working chamber 4 can be directly output through the working oil hole 12; the oil supply chamber 5 can replenish the pressure of the working chamber 4 during the braking process to ensure sufficient braking force. After the braking pressure is replenished, the oil supply chamber 5 and the oil inlet hole 11 are connected to relieve the pressure in the oil supply chamber 5, so that the balance piston 2 can continue to slide and brake after the pressure replenishment is completed. Before the braking pressure replenishment is completed, the oil supply chamber 5 and the oil inlet hole 11 are blocked by the one-way component 7 to avoid pressure replenishment failure. The end of the main piston 3 is positioned in the main piston 3, and the end of the main piston 3 is limited by the fixed support 6, so that the position of the one-way component 7 is more stable and will not be affected by the shaking of the balance piston 2, thereby ensuring that the working state of the one-way component 7 is not disturbed, thereby achieving stable pressure relief. The balancing piston 2 also has a balancing flow channel 23 that can connect the oil supply chamber 5 and the working chamber 4. The balancing piston 2 is connected to a one-way blocking member 9 that only allows the fluid in the balancing flow channel 23 to enter the working chamber 4 from the oil supply chamber 5. The one-way blocking member 9 is located in the working chamber 4, and the other end of the movable rod 8 is inserted into the one-way blocking member 9.In this way, the high-pressure fluid generated by the compression of the oil supply chamber 5 can enter the working chamber 4 through the balancing flow channel 23 to produce a pressure-compensating effect, thereby increasing the braking working pressure. The provision of a one-way blocking member 9 can prevent direct pressure relief in the working chamber 4. At the same time, the movable rod 8 can also be constrained by the one-way blocking member 9, ensuring the stable position of the movable rod 8. A spring seat 10 is provided in the working chamber 4, which always abuts against the end face of the balancing piston 2. The working chamber 4 also includes a return spring 50, a spring base 60, and a guide rod 70. The two ends of the return spring 50 act on the spring seat 10 and the spring base 60 respectively. The spring base 60 abuts the bottom surface of the working chamber. The guide rod 70 is axially connected to the spring base 60 and is slidably connected to the spring seat 10 to provide guidance for the movement of the balancing piston 2.

[0037] like Figure 2As shown, the pressure relief structure includes a confluence section 21 and an oil drain hole 24 located within the balancing piston 2 and capable of connecting the oil supply chamber 5 and the oil inlet hole 11. The two ends of the movable rod 8 are respectively located within the working chamber 4 and within the confluence section 21. The movable rod 8 can move axially toward the one-way component 7 and push the one-way component 7 up. There are multiple oil drain holes 24, all of which are connected to the confluence section 21. The ports connecting the oil drain holes 24 and the confluence section 21 are spaced around the periphery of the movable rod 8. Specifically, the end face of the balancing piston 2 has a boss-shaped connecting portion 22, the confluence section 21 is located on the end face of the connecting portion 22, and the end face of the main piston 3 has a positioning groove 31 connected to the oil inlet hole 11. The connecting portion 22 is positioned and embedded in the positioning groove 31 and is sealed with the circumferential inner wall of the positioning groove 31. In this way, the position of the end of the balancing piston 2 can be fully constrained by the inner wall of the positioning groove 31 by the cooperation between the connecting portion 22 and the positioning groove 31, while preventing the fluid in the oil supply chamber 5 from invading the other side of the one-way component 7, ensuring the blocking and sealing effect of the one-way component 7 on the confluence section 21, and facilitating the stability of pressure relief. In this way, when pressure relief is performed, the fluid can flow through multiple oil drain holes 24 arranged circumferentially around the movable rod 8. The number of oil drain holes 24 can be two or more, so that the impact force of the pressurized fluid in different oil drain holes 24 on the movable rod 8 against the one-way component 7 is dispersed, reducing the phenomenon of the movable rod 8 being shaken or even offset by the impact, thereby making the open state and position of the one-way component 7 more stable, ensuring stable pressure relief. Preferably, the oil drain holes 24 are arranged radially from the outside to the inside toward the side where the one-way component 7 is located. This helps to reduce the direct impact of the fluid passing through the oil drain holes 24 on the movable rod 8, thereby reducing the probability that the shaking of the movable rod 8 will affect the open state of the one-way component 7. The one-way assembly 7 includes a compression spring 71 and a spherical valve block 72. The compression spring 71 is arranged axially along the movable rod 8. The two ends of the compression spring 71 act on the main piston 3 and the valve block 72, respectively. The valve block 72 abuts against the balancing piston 2 and blocks the confluence section 21. This ensures a sealing effect while ensuring that the movable rod 8 can effectively lift the valve block 72 during pressure relief. After pressure relief is completed, the movable rod 8 is reset and the valve block 72 can also be stably reset under the action of the compression spring 71. Specifically, the one-way sealing member 9 includes an annular valve member 91, a spring member 92, and a support plate 93 fixed relative to the balancing piston 2. The support plate 93 abuts against the spring seat 10. The annular valve member 91 is sleeved on the outer periphery of the movable rod 8 and is sealed with the movable rod 8. The two ends of the spring member 92 act on the annular valve member 91 and the support plate 93, respectively, so that the annular valve member 91 always has a tendency to block the balancing flow channel 23. The end of the movable rod 8 abuts against the support plate 93. In this way, the annular valve member 91 can prevent the fluid from leaking from the inside of the one-way sealing member 9, and the movable rod 8 can provide position positioning for the annular valve member 91, so that the opening and closing state of the one-way sealing member 9 is stable. At the same time, the support plate 93 can limit the stroke and position of the movable rod 8, which is conducive to improving the stability of the position state of the movable rod 8.The movable rod 8 comprises a connected push rod section 81 and a connecting section 82. The diameter of the push rod section 81 is smaller than that of the connecting section 82, allowing the push rod section 81 to abut against the valve block 72. The annular valve member 91 is permanently mounted on the outer circumference of the connecting section 82. This abutment of the push rod section 81 (with a smaller diameter) against the valve block 72 ensures a sufficient flow cross-section for the confluence section 21, reduces the impact force exerted on the movable rod 8 by the fluid in the oil drain hole 24, reduces the likelihood of movable rod 8 shaking, and improves pressure relief stability.

[0038] like Figure 3 As shown, this is the structural state of the lower brake valve after the pressure replenishment is completed. At this time, the pressure in the working chamber 4 gradually becomes higher than the pressure in the oil supply chamber 5, so that the movable rod 8 moves toward the one-way component 7 under the action of the pressure difference at both ends and triggers the one-way component 7 to open the confluence section 21, so that the oil inlet hole 11 is connected to the oil supply chamber 5 to relieve pressure.

[0039] like Figure 4 As shown, at this time, the push rod section 81 is pressed against the valve block 72, and the hydraulic oil can flow through the oil drain hole 24 and the confluence section 21 to achieve pressure relief and backflow.

[0040] like Figure 5As shown, the annular valve body 1 includes a valve plate 911, a sealing ring 912, and a spring washer 913 that abut against each other in sequence. The valve plate 911 abuts against the working piston and is sleeved on the outer circumference of the movable rod 8. One end of the spring member 92 acts on the spring washer 913. The inner edge of the sealing ring 912 has a sealing lip 9121 arranged around the circumference. The sealing lip 9121 has an interference fit with the outer circumference of the connecting section 82. The sealing lip 9121 is arranged in a trumpet shape with the large end facing the side where the valve plate 911 is located. The sealing lip 9121 is circumferentially sealed with the outer circumference of the movable rod 8. The sealing lip 9121 is provided on the inner edge of the sealing ring 912 to form a circumferential linear seal with the outer circumference of the movable rod 8. The sealing lip 9121 is arranged in a trumpet shape. This helps the sealing lip 9121 resist the pressure of the working chamber 4 to maintain contact with the movable rod 8, while ensuring the sealing effect. It also reduces the loss of the movable rod 8 when sliding relative to the sealing ring 912, which helps extend the working life. The sealing ring 912 has an annular boss 9122 protruding toward the side where the support plate 93 is located. The inner wall of the annular boss 9122 is spaced apart from the outer peripheral surface of the movable rod 8, and the sealing lip 9121 is located on the inner wall of the annular boss 9122. The sealing lip 9121 is arranged on the inner wall of the protruding annular boss 9122, and the inner wall of the annular boss 9122 is spaced apart from the outer peripheral surface of the movable rod 8. In this way, the area where the sealing lip 9121 is located is more susceptible to the radial pressure of the outer periphery and evenly abuts against the movable rod 8, so that the sealing lip 9121 remains in close contact with the movable rod 8 even if it wears. At the same time, the closer the annular boss 9122 is to the main body of the sealing ring 912, the less likely it is to be deformed by the pressure of the external fluid. Therefore, a portion of the cavity can always be maintained in the annular boss 9122, which is conducive to ensuring the continuous pressure of the external fluid on the annular boss 9122 and extending the maintenance cycle.

[0041] like Figure 6 As shown, the pedal connecting rod assembly 20 can be an existing assembly component with a pedal, which is connected and arranged at the bottom of the valve body 1.

[0042] The specific embodiments described herein are merely illustrative of the spirit of the present invention. Persons skilled in the art may make various modifications, additions, or substitutions to the described specific embodiments without departing from the spirit of the present invention or exceeding the scope of the appended claims.

Claims

1. A brake valve pressure relief structure, comprising a valve body (1) with an oil inlet hole (11), wherein a main piston (3) and a balance piston (2) are slidably connected in the valve body (1), and characterized in that: The pressure relief structure comprises a confluence section (21) located on the end surface of the balancing piston (2) close to the main piston (3), an oil drain hole (24) located on the outer peripheral surface of the balancing piston (2), and a one-way component (7) located between the balancing piston (2) and the main piston (3) and blocking the communication between the confluence section (21) and the oil inlet hole (11). There are at least two oil drain holes (24) and both are connected to the confluence section (21). A movable rod (8) passing through the balancing piston (2) is slidably connected in the balancing piston (2). One end of the movable rod (8) is always located in the confluence section (21) and can move axially toward the one-way component (7) and push the one-way component (7) up. The ports where the oil drain holes (24) communicate with the confluence section (21) are spaced circumferentially around the movable rod (8). Arrangement: The oil drain hole (24) is tilted from the outside to the inside along the radial direction of the balancing piston (2) toward the side where the one-way component (7) is located, and the ports of the oil drain holes (24) communicating with the confluence section (21) are evenly spaced around the circumference of the movable rod (8). The outer periphery of the middle section of the movable rod (8) or the outer periphery of the other end of the movable rod (8) is sealed with the balancing piston (2). The end face of the balancing piston (2) has a boss-shaped connecting portion (22), and the confluence section (21) is located on the end face of the connecting portion (22). The end face of the main piston (3) has a positioning groove (31) whose bottom is connected to the oil inlet hole (11), and the connecting portion (22) is positioned and embedded in the positioning groove (31) and is sealed with the circumferential inner wall of the positioning groove (31).

2. The pressure relief structure of the brake valve according to claim 1, characterized in that: An annular support member (6) is fixedly connected to the inner cavity side wall of the valve body (1); one end of the main piston (3) against which the balance piston (2) abuts is positioned and inserted into the support member (6); and the one-way component (7) is positioned opposite to the support member (6) along the radial direction of the main piston (3).

3. The pressure relief structure of the brake valve according to claim 1 or 2, characterized in that: The one-way assembly (7) includes a compression spring (71) and a spherical valve block (72). The compression spring (71) is arranged along the axial direction of the movable rod (8) and is located in the main piston (3). The two ends of the compression spring (71) act on the main piston (3) and the valve block (72) respectively. The valve block (72) is located at the joint surface between the main piston (3) and the balancing piston (2) and abuts against the balancing piston (2) to block the confluence section (21).

4. The pressure relief structure of the brake valve according to claim 3, characterized in that: The balancing piston (2) further comprises a balancing flow channel (23), the two ends of which are respectively located on the outer peripheral surface of the balancing piston (2) and on the side of the balancing piston (2) away from the main piston (3). The side of the balancing piston (2) away from the main piston (3) is connected to a one-way blocking member (9) which only allows the fluid in the balancing flow channel (23) to flow out, and the other end of the movable rod (8) is inserted into the one-way blocking member (9).

5. The pressure relief structure of the brake valve according to claim 4, characterized in that: The one-way blocking member (9) includes an annular valve member (91), a spring member (92) and a support plate (93) fixed relative to the balancing piston (2). The annular valve member (91) is sleeved on the outer periphery of the movable rod (8) and is sealed with the movable rod (8). The two ends of the spring member (92) act on the annular valve member (91) and the support plate (93) respectively and make the annular valve member (91) always have a tendency to block the balancing flow channel (23). The end of the movable rod (8) abuts against the support plate (93).

6. The pressure relief structure of the brake valve according to claim 5, characterized in that: The movable rod (8) comprises a push rod section (81) and a connecting section (82) connected to each other. The diameter of the push rod section (81) is smaller than the diameter of the connecting section (82). The push rod section (81) can abut against the valve block (72), and the annular valve member (91) is always sleeved on the outer periphery of the connecting section (82).

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