Foot brake valve and pneumatic dual-circuit service brake system

Abstract

The application relates to the brake technical field and provides a foot brake valve and a pneumatic double-circuit service brake system. The foot brake valve comprises a relay piston, which divides a relay piston cavity into a first piston cavity and a second piston cavity; and a differential pressure adjusting mechanism arranged in a differential pressure adjusting cavity; wherein the second piston cavity is divided into a sub-chamber I and a sub-chamber II by a partition wall with a gas passage; the differential pressure adjusting mechanism can seal the gas passage and can open the gas passage under the action of the gas pressure of the sub-chamber I; during the braking process, the first piston cavity is first filled with air to drive the relay piston to move, then the sub-chamber I is filled with air to drive the differential pressure adjusting mechanism to open the gas passage, and the gas pressure in the second piston cavity drives the relay piston to move to force balance. The differential pressure value of the two piston cavities of the foot brake valve can be adjusted through the differential pressure adjusting mechanism, the gas pressure output by the two piston cavities is adapted to the actual working condition of the vehicle, and therefore the effectiveness and adaptability of the service brake are improved and enhanced.

Description

Technical Field

[0001] This invention relates to the field of braking technology, and more specifically, to a foot brake valve and a dual-circuit air-pressure service brake system. Background Technology

[0002] The foot brake valve is a major component of the service braking system of commercial vehicles and other vehicles, and plays a vital role in the vehicle's braking safety.

[0003] The service braking system is usually a dual-circuit air-pressure service braking system, with the two circuits typically connected to the front and rear wheels of the vehicle. The foot brake valve has two piston chambers that are connected to the two circuits of the dual-circuit air-pressure service braking system, respectively. There is a certain difference in the air pressure output from the two piston chambers, so that there is a difference in the air pressure received by the two circuits, thereby meeting the actual braking requirements.

[0004] In the existing technology, the pressure difference between the two piston chambers of the foot brake valve is a fixed value and cannot be adjusted. As a result, the air pressure output by the two piston chambers cannot adapt to various operating conditions of the vehicle, and cannot better achieve the effectiveness and adaptability of vehicle service braking.

[0005] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of the present invention, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0006] In view of this, the present invention provides a foot brake valve with adjustable differential pressure and a dual-circuit air brake system, wherein the differential pressure between the first piston chamber and the sub-chamber of the second piston chamber of the foot brake valve can be adjusted by a differential pressure adjustment mechanism, so that the air pressure output by the two piston chambers is adapted to the actual operating conditions of the vehicle, thereby improving the effectiveness and adaptability of the vehicle's braking.

[0007] One aspect of the present invention provides a foot brake valve, comprising: a relay piston disposed in a relay piston chamber, the relay piston dividing the relay piston chamber into a first piston chamber located at a first end face and a second piston chamber located at a second end face; a differential pressure regulating mechanism disposed in a differential pressure regulating chamber, the first end of the differential pressure regulating chamber extending into the second piston chamber; wherein the second piston chamber is divided into a sub-chamber one and a sub-chamber two by a partition wall, the partition wall being disposed at the second end face of the relay piston and / or the first end of the differential pressure regulating chamber, the partition wall having a gas passage connecting the sub-chamber one, the first end of the differential pressure regulating chamber, and the sub-chamber two, the differential pressure regulating mechanism being able to open the gas passage under the action of the gas pressure in the sub-chamber one, and being able to seal the gas passage under the action of the gas pressure at the second end of the differential pressure regulating chamber; during braking, firstly, air enters the first piston chamber to push the relay piston to move, then air enters the sub-chamber one to push the differential pressure regulating mechanism to open the gas passage, and the gas pressure in the second piston chamber pushes the relay piston to move until the force is balanced.

[0008] In some embodiments, the area of ​​the first end face of the relay piston is smaller than the area of ​​its second end face. When the relay piston is in a state of force equilibrium, the pressure difference between the first piston chamber and the sub-chamber is greater than, equal to, or less than zero.

[0009] In some embodiments, the second end of the differential pressure regulating chamber is connected to an air suspension system or an airbag, the air pressure output by the air suspension system and the airbag being determined according to the vehicle load.

[0010] In some embodiments, the gas passage includes a first sub-channel connecting the first sub-chamber to the first end of the differential pressure regulating chamber and a second sub-channel connecting the first end of the differential pressure regulating chamber to the second sub-chamber; the wall surface of the first end of the differential pressure regulating chamber is further provided with an annular retaining ring, and the differential pressure regulating mechanism can abut against the annular retaining ring under the action of the air pressure at the second end of the differential pressure regulating chamber to seal the first sub-channel, and can move away from the annular retaining ring under the action of the air pressure in the first sub-chamber to open the gas passage.

[0011] In some embodiments, the differential pressure regulating mechanism includes a sealing valve disposed at its first end. The sealing valve includes a sealing skeleton with a through hole and a sealing sleeve covering the sealing skeleton. The sealing sleeve seals the through hole and can be opened by the air pressure in the second sub-chamber.

[0012] In some embodiments, the differential pressure regulating mechanism further includes a differential pressure regulating piston disposed at the second end of the differential pressure regulating cavity, the differential pressure regulating piston being connected to the sealing frame via a differential pressure regulating spring.

[0013] In some embodiments, a pair of limiting structures are provided at both ends of the differential pressure regulating cavity, and the pair of limiting structures limit the range of motion of the differential pressure regulating piston.

[0014] In some embodiments, the partition wall includes a first annular wall disposed on the second end face of the relay piston and a second annular wall disposed on the first end of the differential pressure regulating cavity. The first annular wall abuts against the second annular wall and divides the second piston cavity into a sub-chamber one located on one side of the first annular wall and a sub-chamber two located on one side of the second annular wall.

[0015] In some embodiments, the foot brake valve further includes: a main piston disposed in a main piston chamber; a first valve disposed in a first valve chamber, located at a first end face of the relay piston, wherein in a non-braking state, one end of the first valve abuts against the inner wall of the first valve chamber and the other end is supported by a first spring, and during the braking process, the main piston pushes the first valve to open the passage from the first valve chamber to the first piston chamber; and a second valve disposed in a second valve chamber, located at a second end face of the relay piston, wherein in a non-braking state, one end of the second valve abuts against the inner wall of the second valve chamber and the other end is supported by a second spring, and during the braking process, the relay piston pushes the second valve to open the passage from the second valve chamber to the second piston chamber.

[0016] In some embodiments, under the brake release state, the gas pressure in the main piston chamber pushes the main piston to reset, the first spring pushes the first valve to reset, the gas pressure in the first piston chamber is discharged to the exhaust port of the foot brake valve, the gas pressure in the second piston chamber pushes the relay piston to reset, the second spring pushes the second valve to reset, the gas in the first sub-chamber is discharged to the exhaust port, and the gas in the second sub-chamber is discharged to the exhaust port through the first end of the differential pressure regulating chamber and the first sub-chamber.

[0017] In some embodiments, the foot brake valve further includes: a first housing and a second housing that are sealed together, the first housing defining a first piston chamber with a first end face of the relay piston, the differential pressure regulating chamber being disposed in the second housing, and the second housing defining a second piston chamber with a second end face of the relay piston.

[0018] Another aspect of the present invention provides a pneumatic dual-circuit service braking system, wherein the pneumatic dual-circuit service braking system is configured with a foot brake valve as described in any of the above embodiments, wherein the first piston chamber and the sub-chamber of the foot brake valve are respectively connected to two circuits of the pneumatic dual-circuit service braking system.

[0019] The beneficial effects of this invention compared to the prior art include at least the following:

[0020] The foot brake valve of the present invention is provided with a differential pressure regulating mechanism that can open the gas passage under the action of the gas pressure in the first sub-chamber and seal the gas passage under the action of the gas pressure at the second end of the differential pressure regulating chamber. When the force of the differential pressure regulating mechanism sealing the gas passage is large, the gas pressure in the first sub-chamber needs to overcome a large force to open the gas passage during the braking process. Thus, the gas pressure in the first sub-chamber is large when the relay piston moves to the force balance. When the force of the differential pressure regulating mechanism sealing the gas passage is small, the gas pressure in the first sub-chamber can open the gas passage by overcoming a small force during the braking process. Thus, the gas pressure in the first sub-chamber is small when the relay piston moves to the force balance.

[0021] Therefore, by adjusting the force of the differential pressure regulating mechanism sealing the gas passage in the initial state, the differential pressure value between the first piston chamber and the sub-chamber can be adjusted, so that the air pressure output by the two piston chambers can be adapted to the actual working conditions of the vehicle, thereby improving the effectiveness and adaptability of the vehicle's braking.

[0022] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit the invention. Attached Figure Description

[0023] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention. It is obvious that the drawings described below are merely some embodiments of the invention, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0024] Figure 1 A schematic diagram of the foot brake valve in an embodiment of the present invention is shown;

[0025] Figure 2 A schematic diagram of the differential pressure regulating mechanism of the foot brake valve in an embodiment of the present invention is shown;

[0026] Figure 3 This diagram shows a structural schematic of a portion of the housing of the foot brake valve in an embodiment of the present invention;

[0027] Figure 4 This diagram shows the structural schematic of the sealing valve of the differential pressure regulating mechanism in an embodiment of the present invention;

[0028] Figure 5 A schematic diagram of the relay piston of the foot brake valve in an embodiment of the present invention is shown. Detailed Implementation

[0029] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to fully and completely convey the concept of the exemplary embodiments to those skilled in the art.

[0030] The accompanying drawings are merely illustrative of the invention and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and therefore repeated descriptions of them will be omitted. Some block diagrams shown in the drawings are functional entities and do not necessarily correspond to physically or logically independent entities. These functional entities can be implemented in software, in one or more hardware modules or integrated circuits, or in different network and / or processor devices and / or microcontroller devices.

[0031] The use of terms such as "first," "second," and similar terms in the specific description does not indicate any order, quantity, or importance, but is merely used to distinguish different components. In the description of this invention, the terms "upper," "lower," "left," "right," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention 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, and therefore should not be construed as a limitation of the invention.

[0032] It should be noted that, unless otherwise specified, the embodiments of the present invention and the features in different embodiments can be combined with each other.

[0033] Figure 1 The structure of the foot brake valve in an embodiment of the present invention is shown; see reference. Figure 1 As shown, the foot brake valve provided in this embodiment of the invention includes:

[0034] A relay piston 10 is disposed in a relay piston chamber, which divides the relay piston chamber into a first piston chamber 11 located on its first end face and a second piston chamber 12 located on its second end face.

[0035] The differential pressure regulating mechanism 20 is disposed in the differential pressure regulating chamber 22, and the first end 22a of the differential pressure regulating chamber 22 extends into the second piston chamber 12.

[0036] The second piston chamber 12 is divided into sub-chamber 12a and sub-chamber 2b by a partition wall. The partition wall is disposed on the second end face of the relay piston 10 and / or the first end 22a of the differential pressure regulating chamber 22. The partition wall has a gas passage 220 that connects sub-chamber 12a, the first end 22a of the differential pressure regulating chamber 22 and sub-chamber 2b. The differential pressure regulating mechanism 20 can open the gas passage 220 under the action of the gas pressure in sub-chamber 12a and can seal the gas passage 220 under the action of the gas pressure in the second end 22b of the differential pressure regulating chamber 22.

[0037] During braking, firstly, air enters the first piston chamber 11 to drive the relay piston 10 to move, then air enters the sub-chamber 12a to drive the differential pressure regulating mechanism 20 to open the gas passage 220, and the gas pressure in the second piston chamber 12 drives the relay piston 10 to move until the force is balanced.

[0038] The foot brake valve of the present invention is provided with a differential pressure regulating mechanism 20, which can open the gas passage 220 under the action of the gas pressure in the sub-chamber 12a and seal the gas passage 220 under the action of the gas pressure at the second end 22b of the differential pressure regulating chamber 22. When the force of the differential pressure regulating mechanism 20 sealing the gas passage 220 is large, the gas pressure in the sub-chamber 12a needs to overcome a large force to open the gas passage 220 during the braking process. Thus, the gas pressure in the sub-chamber 12a is large when the relay piston 10 moves to the force balance. When the force of the differential pressure regulating mechanism 20 sealing the gas passage 220 is small, the gas pressure in the sub-chamber 12a can open the gas passage 220 by overcoming a small force during the braking process. Thus, the gas pressure in the sub-chamber 12a is small when the relay piston 10 moves to the force balance.

[0039] Thus, by adjusting the force of the differential pressure regulating mechanism 20 sealing the gas passage 220 in the initial state, the differential pressure value between the first piston chamber 11 and the sub-chamber 12a can be adjusted, so that the air pressure output by the first piston chamber 11 and the sub-chamber 12a can be adapted to the actual working conditions of the vehicle, thereby improving the effectiveness and adaptability of the vehicle's braking.

[0040] In some embodiments, the area of ​​the first end face of the relay piston 10 is smaller than the area of ​​its second end face. When the relay piston 10 is in a state of force equilibrium, the pressure difference between the first piston chamber 11 and the sub-chamber 12a is greater than, equal to, or less than zero.

[0041] When the relay piston 10 is in a state of force equilibrium, the force on its first end face is equal to the force on its second end face; and the area of ​​the first end face of the relay piston 10 is smaller than the area of ​​its second end face. Therefore, without considering the differential pressure adjustment mechanism 20, when the relay piston 10 is in a state of force equilibrium, the gas pressure in the first piston chamber 11 is greater than the gas pressure in the second piston chamber 12. That is, without considering the differential pressure adjustment mechanism 20, the gas pressure output by the first piston chamber 11 and the second piston chamber 12 has a certain differential pressure value. Furthermore, in the initial state (i.e., non-braking state), if the differential pressure regulating mechanism 20 has a force sealing the gas passage 220, then during braking, as the relay piston 10 moves to force equilibrium, the gas pressure in sub-chamber 12a must overcome the force of the differential pressure regulating mechanism 20 sealing the gas passage 220. Thus, when the relay piston 10 is in force equilibrium, the gas pressure in sub-chamber 12a will increase compared to the case without considering the differential pressure regulating mechanism 20, thereby reducing the pressure difference between the first piston chamber 11 and sub-chamber 12a. Based on the force of the differential pressure regulating mechanism 20 sealing the gas passage 220 in the initial state, the pressure difference between the first piston chamber 11 and sub-chamber 12a during braking can be greater than, equal to, or less than zero. This ensures that the air pressure output by the first piston chamber 11 and sub-chamber 12a adapts to the actual operating conditions of the vehicle, improving the effectiveness and adaptability of the vehicle's braking.

[0042] In some embodiments, the second end 22b of the differential pressure regulating chamber 22 is connected to the air suspension system or airbag, and the air pressure output by the air suspension system and airbag is determined according to the vehicle load.

[0043] The air pressure output by the vehicle's air suspension system (ECAS) and airbags is automatically determined according to the vehicle's load, which is existing technology. In this embodiment, the second end 22b of the differential pressure regulating chamber 22 is connected to the air suspension system or airbag, so that the force of the differential pressure regulating mechanism 20 sealing the gas passage 220 in the initial state is automatically adjusted according to the vehicle load. Specifically, when the vehicle load is large, such as when the vehicle is fully loaded, the force of the differential pressure regulating mechanism 20 sealing the gas passage 220 in the initial state is large; when the vehicle load is small, the force of the differential pressure regulating mechanism 20 sealing the gas passage 220 in the initial state is small; in particular, when the vehicle is unloaded, the differential pressure regulating mechanism 20 is in a free state, and the gas passage 220 is not sealed. In this way, the pressure difference between the first piston chamber 11 and the sub-chamber 12a during braking can be automatically adjusted according to the vehicle load, and its pressure difference value can adapt to the actual operating conditions of the vehicle, significantly improving and enhancing the effectiveness and adaptability of the vehicle's service braking.

[0044] Figure 2 The structure of the differential pressure regulating mechanism of the foot brake valve is shown. Figure 3 This shows the structure of a portion of the foot brake valve housing; combined with Figures 1 to 3 As shown, in some embodiments:

[0045] The gas channel 220 includes a sub-channel 220a that connects the first end 22a of the sub-chamber 12a to the first end 22a of the differential pressure regulating chamber 22 and a sub-channel 220b that connects the first end 22a of the differential pressure regulating chamber 22 to the second sub-chamber 12b.

[0046] The wall surface of the first end 22a of the differential pressure regulating chamber 22 is also provided with an annular retaining ring 222. The differential pressure regulating mechanism 20 can abut against the annular retaining ring 222 under the action of the air pressure at the second end 22b of the differential pressure regulating chamber 22 to seal the sub-channel 220a, and can leave the annular retaining ring 222 under the action of the air pressure in the sub-chamber 12a to open the gas channel 220.

[0047] Sub-chamber 12a is connected to sub-chamber 12b via sub-channel 1 (220a) and sub-channel 220b, through the first end (22a) of differential pressure regulating chamber 22. The gas passage 220 is opened and sealed through the cooperation of the annular retaining ring (222) and the differential pressure regulating mechanism (20). When the vehicle is under load, the force from the second end (22b) of the differential pressure regulating chamber (22) pushes the differential pressure regulating mechanism (20) against the annular retaining ring (222) to seal sub-channel 1 (220a). During braking, the force from sub-chamber 12a pushes the differential pressure regulating mechanism (20) away from the annular retaining ring (222) to open the gas passage 220.

[0048] Figure 4 The structure of the sealing valve of the differential pressure regulating mechanism is shown; combined with Figures 1 to 4 As shown, in some embodiments, the differential pressure regulating mechanism 20 includes a sealing valve 202 disposed at its first end 22a. The sealing valve 202 includes a sealing frame 2024 with a through hole 2022 and a sealing sleeve 2026 covering the sealing frame 2024. The sealing sleeve 2026 seals the through hole 2022 and can open the through hole 2022 under the action of the air pressure in the second sub-chamber 12b.

[0049] Through the design of the through hole 2022 and the movable sealing sleeve 2026, and in combination with the design of sub-channel one 220a and sub-channel two 220b, the gas in sub-chamber two 12b enters the first end 22a of the differential pressure regulating chamber 22 through sub-channel two 220b in the braking release state, pushes open the sealing sleeve 2026 through the through hole 2022, and enters sub-chamber one 12a, so as to be discharged to the exhaust port 70 through sub-chamber one 12a.

[0050] Continue to refer to Figures 1 to 4 As shown, in some embodiments, the differential pressure regulating mechanism 20 further includes a differential pressure regulating piston 206 disposed at the second end 22b of the differential pressure regulating cavity 22, and the differential pressure regulating piston 206 is connected to the sealing frame 2024 through a differential pressure regulating spring 204.

[0051] The differential pressure regulating piston 206 and sealing frame 2024, which are connected at both ends of the differential pressure regulating chamber 22 by the differential pressure regulating spring 204, enable the differential pressure regulating mechanism 20 to move under the action of gas pressure from both ends of the differential pressure regulating chamber 22, so as to open and seal the gas passage 220.

[0052] The differential pressure regulating piston 206 and the inner wall of the differential pressure regulating chamber 22 can be sealed together by a sealing ring 23.

[0053] Continue to refer to Figures 1 to 4 As shown, in some embodiments, a pair of limiting structures are provided at both ends of the differential pressure regulating cavity 22, and the pair of limiting structures limit the range of motion of the differential pressure regulating piston 206.

[0054] A pair of limiting structures may specifically include a limiting step 24 provided near the first end 22a of the differential pressure regulating cavity 22 and a limiting snap ring 26 provided near the second end 22b of the differential pressure regulating cavity 22, with the limiting snap ring 26 disposed in the groove 26'.

[0055] By means of the limiting snap ring 26, when the vehicle is unloaded, the differential pressure regulating piston 206 will not be pushed out of the differential pressure regulating chamber 22 due to excessive compressed air pressure from sub-chamber 12a acting on its right side; by means of the limiting step 24, when the vehicle is fully loaded, the differential pressure regulating piston 206 will not move to the right and make mechanical contact with the sealing valve 202 due to excessive processed control air pressure from ECAS or airbag acting on its left side, thus preventing the sealing valve 202 from being pushed open to the left and affecting the conduction between sub-chamber 12a and sub-chamber 22b.

[0056] In other embodiments, the range of motion of the differential pressure regulating piston 206 can also be limited by other limiting structures.

[0057] Figure 5 This illustrates the structure of the relay piston of the foot brake valve; combined with Figures 1 to 5 As shown, in some embodiments, the partition wall includes a first annular wall 18 disposed on the second end face of the relay piston 10 and a second annular wall 28 disposed on the first end 22a of the differential pressure regulating cavity 22. The second annular wall 28 abuts against the first annular wall 18 and divides the second piston cavity 12 into a sub-chamber 12a located on one side of the first annular wall 18 and a sub-chamber 12b located on one side of the second annular wall 28.

[0058] An O-ring 19 can be used to achieve a sealing fit between the first annular wall 18 and the second annular wall 28. The sealing fit between the first annular wall 18 and the second annular wall 28 can form a stable partition wall on the one hand, and facilitate the assembly of the relay piston 10 on the other hand.

[0059] Continue to refer to Figures 1 to 5 As shown, in some embodiments, the foot brake valve further includes:

[0060] The main piston 30 is disposed in the main piston chamber 33;

[0061] The first valve 40 is disposed in the first valve chamber 44 and located on the first end face of the relay piston 10. In the non-braking state, one end of the first valve 40 abuts against the inner wall of the first valve chamber 44 and the other end is supported by the first spring 48. During the braking process, the main piston 30 pushes the first valve 40 to open the passage from the first valve chamber 44 to the first piston chamber 11.

[0062] The second valve 50 is disposed in the second valve cavity 55 and located on the second end face of the relay piston 10. In the non-braking state, one end of the second valve 50 abuts against the inner wall of the second valve cavity 55 and the other end is supported by the second spring 58. During the braking process, the relay piston 10 pushes the second valve 50 to open the passage from the second valve cavity 55 to the second piston cavity 12.

[0063] Specifically, during braking, the main piston 30 moves downward, pushing the first valve 40 to disengage from the inner wall of the first valve chamber 44, and thus from the first housing 62. Gas in the first valve chamber 44 then enters the main piston chamber 33 through the opening between the first valve 40 and the first housing 62. The main piston chamber 33 is connected to the first piston chamber 11 through an internal channel on the first housing 62. Further, the gas in the first piston chamber 11 pushes the relay piston 10, which in turn pushes the second valve 50 downward, disengaging from the inner wall of the second valve chamber 55, and thus from the second housing 63. Gas in the second valve chamber 55 then enters the second piston chamber 12 through the opening between the second valve 50 and the second housing 63.

[0064] When the vehicle is unloaded, the processed, smaller control air pressure from the ECAS or airbag acts on the left side of the differential pressure regulating piston 206 through the second end 22b of the differential pressure regulating chamber 22. Since the control air pressure is small, it is insufficient to push the differential pressure regulating piston 206 to the right. At this time, the differential pressure regulating spring 204 is in a free extension state, and there is no force interaction between the sealing valve 202 and the annular retaining ring 222, that is, the sealing valve 202 does not play a sealing role on the annular retaining ring 222. Then, at this time, the compressed air in the sub-chamber 12a can smoothly enter the sub-chamber 12b through the gas passage 220 and act on the outer annular surface 10b-2 of the second end face of the relay piston 10. Currently, the compressed air pressure in sub-chamber 12a and sub-chamber 12b is equal, acting together on the second end face of the relay piston 10. As the compressed air pressure in sub-chambers 12a and 12b increases, it pushes the relay piston 10 upward against the air pressure in the first piston chamber 11. The second valve 50 then resets (driven by the second spring 58) until it contacts the inner wall of the second valve chamber 55. At this point, the second valve 50 is sealed to the inner walls of the relay piston 10 and the second valve chamber 55, and the relay piston 10 is in a state of force equilibrium. However, due to the structural characteristics of the relay piston 10, the compressed air pressure in its first piston chamber 11 is higher than that in sub-chamber 12a. Therefore, there is a certain pressure difference between the output pressure of the first piston chamber 11 and sub-chamber 12a.

[0065] As the vehicle load gradually increases, the processed control air pressure from the ECAS or airbag gradually increases, acting on the left side of the differential pressure regulating piston 206, pushing it to the right. This compresses the differential pressure regulating spring 204, causing the sealing valve 202 to come into contact with the annular retaining ring 222 under the spring force, achieving a seal. During braking, the compressed air in sub-chamber 12a acts on the right side of the sealing valve 202 via sub-channel 220a. As the compressed air pressure in sub-chamber 12a increases, it pushes the sealing valve 202 to the left, overcoming the spring force of the differential pressure regulating spring 204. This disengages the sealing valve 202 from the annular retaining ring 222, and the compressed air continues to enter sub-chamber 12b via sub-channel 220b. Currently, the compressed air pressure in sub-chamber 12a is higher than that in sub-chamber 12b. The compressed air in both sub-chambers 12a and 12b acts on the second end face of the relay piston 10. As the compressed air pressure in both chambers increases, it pushes the relay piston 10 upward against the air pressure in the first piston chamber 11, causing the second valve 50 to reset (pushed by the second spring 58) until it contacts the inner wall of the second valve chamber 55. At this time, the second valve 50 is in a sealed state with the relay piston 10 and the inner wall of the second valve chamber 55, and the relay piston 10 is in a state of force balance. When the vehicle is under load, the compressed air pressure in sub-chamber 12a will gradually approach or even exceed the compressed air pressure in the first piston chamber 11 as the vehicle load increases. That is, the pressure difference between the output air pressure of the first piston chamber 11 and sub-chamber 12a of the foot brake valve gradually decreases or even becomes negative as the vehicle load increases.

[0066] Therefore, the foot brake valve in this embodiment can automatically adjust the pressure difference between the output air pressure of the two piston chambers according to the vehicle's load conditions, ensuring that the pressure difference can adapt to the actual working conditions of the vehicle, and significantly improving the effectiveness and adaptability of vehicle braking.

[0067] Continue to combine Figures 1 to 5 As shown, in some embodiments, the first valve 40 abuts against the inner wall of the first valve cavity 44 via the first spring 48, and the second valve 50 abuts against the inner wall of the second valve cavity 55 via the second spring 58;

[0068] In the brake release state, the gas pressure in the main piston chamber 33 pushes the main piston 30 to reset, the first spring 48 pushes the first valve 40 to reset, the gas pressure in the first piston chamber 11 is discharged to the exhaust port 70 of the foot brake valve, the gas pressure in the second piston chamber 12 pushes the relay piston 10 to reset, the gas in the first sub-chamber 12a is discharged to the exhaust port 70, and the gas in the second sub-chamber 12b is discharged to the exhaust port 70 through the first end 22a of the differential pressure regulating chamber 22 and the first sub-chamber 12a.

[0069] Specifically, when the driver releases the pedal, the main piston 30 moves upward under the action of compressed air in the main piston chamber 33, disengaging from the first valve 40. The first valve 40 then restores its sealing function with the inner wall of the first valve chamber 44 under the action of the first spring 48. Compressed air in the first piston chamber 11 enters the exhaust port 70 of the foot brake valve through the internal channel of the housing. Simultaneously, the relay piston 10 moves upward under the action of compressed air in sub-chambers 12a and 12b, disengaging from the second valve 50. The second valve 50 can then continue to restore its sealing function with the inner wall of the second valve chamber 55 under the action of the second spring 58. Furthermore, compressed air in sub-chamber 12a enters the exhaust port 70, and compressed air in sub-chamber 12b enters sub-chamber 12a through the through hole 2022 of the sealing valve 202 and sub-channel 220a, and is discharged to the exhaust port 70.

[0070] Continue to combine Figures 1 to 5 As shown, in some embodiments, the foot brake valve housing includes a first housing 62 and a second housing 63 that are sealed together. The first housing 62 and the first end face of the relay piston 10 define a first piston chamber 11. The differential pressure regulating chamber 22 is disposed in the second housing 63, and the second housing 63 and the second end face of the relay piston 10 define a second piston chamber 12.

[0071] The sealed connection between the first housing 62 and the second housing 63 facilitates the processing and assembly of the various components of the foot brake valve.

[0072] This invention also provides a pneumatic dual-circuit service braking system, which is equipped with a foot brake valve as described in any of the above embodiments, wherein the first piston chamber 11 and the sub-chamber 12a of the foot brake valve are respectively connected to the two circuits of the pneumatic dual-circuit service braking system.

[0073] With the aforementioned foot brake valve, the dual-circuit air brake system enables adjustable brake air pressure in both circuits. Preferably, the brake air pressure in both circuits can be adaptively adjusted according to the vehicle load, so that the brake air pressure in both circuits is adapted to the actual operating conditions of the vehicle, thereby improving the effectiveness and adaptability of the vehicle's braking.

[0074] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. A foot brake valve, characterized in that, include: A relay piston is disposed in a relay piston chamber, which divides the relay piston chamber into a first piston chamber located on its first end face and a second piston chamber located on its second end face; A differential pressure regulating mechanism is provided in a differential pressure regulating chamber. The first end of the differential pressure regulating chamber extends into the second piston chamber, and the second end of the differential pressure regulating chamber is connected to an air suspension system or an airbag. The air pressure output by the air suspension system and the airbag is determined according to the vehicle load. The second piston chamber is divided into sub-chamber one and sub-chamber two by a partition wall. The partition wall is disposed on the second end face of the relay piston and / or the first end of the differential pressure regulating chamber. The partition wall has a gas passage connecting sub-chamber one, the first end of the differential pressure regulating chamber, and sub-chamber two. The differential pressure regulating mechanism can open the gas passage under the gas pressure of sub-chamber one and can seal the gas passage under the gas pressure of the second end of the differential pressure regulating chamber. During braking, air first enters the first piston chamber to drive the relay piston to move, and then air enters the first sub-chamber to drive the differential pressure regulating mechanism to open the gas passage. The gas pressure in the second piston chamber also drives the relay piston to move until it is in force equilibrium. The area of ​​the first end face of the relay piston is smaller than the area of ​​its second end face. When the relay piston is in force equilibrium, the pressure difference between the first piston chamber and the first sub-chamber is greater than, equal to, or less than zero.

2. The foot brake valve as described in claim 1, characterized in that, The gas channel includes a sub-channel one connecting the first end of the sub-chamber one to the first end of the differential pressure regulating chamber, and a sub-channel two connecting the first end of the differential pressure regulating chamber to the second sub-chamber. The wall surface at the first end of the differential pressure regulating chamber is also provided with an annular retaining ring. The differential pressure regulating mechanism can abut against the annular retaining ring under the action of air pressure at the second end of the differential pressure regulating chamber to seal the first sub-channel, and can leave the annular retaining ring under the action of air pressure in the first sub-chamber to open the gas channel.

3. The foot brake valve as described in claim 2, characterized in that, The differential pressure regulating mechanism includes a sealing valve disposed at its first end. The sealing valve includes a sealing skeleton with a through hole and a sealing sleeve covering the sealing skeleton. The sealing sleeve seals the through hole and can be opened by the air pressure in the second sub-chamber.

4. The foot brake valve as described in claim 3, characterized in that, The differential pressure regulating mechanism further includes a differential pressure regulating piston disposed at the second end of the differential pressure regulating cavity, and the differential pressure regulating piston is connected to the sealing frame through a differential pressure regulating spring.

5. The foot brake valve as described in claim 4, characterized in that, The differential pressure regulating chamber is provided with a pair of limiting structures at both ends, which limit the range of motion of the differential pressure regulating piston.

6. The foot brake valve as described in claim 1, characterized in that, The partition wall includes a first annular wall disposed on the second end face of the relay piston and a second annular wall disposed on the first end of the differential pressure regulating cavity. The first annular wall abuts against the second annular wall and divides the second piston cavity into a sub-chamber one located on one side of the first annular wall and a sub-chamber two located on one side of the second annular wall.

7. The foot brake valve as described in claim 1, characterized in that, Also includes: The main piston is located in the main piston chamber. A first valve is disposed in a first valve chamber and located on the first end face of the relay piston. In the non-braking state, one end of the first valve abuts against the inner wall of the first valve chamber and the other end is supported by a first spring. During the braking process, the main piston pushes the first valve to open the passage from the first valve chamber to the first piston chamber. The second valve is disposed in the second valve chamber and located on the second end face of the relay piston. In the non-braking state, one end of the second valve abuts against the inner wall of the second valve chamber and the other end is supported by the second spring. During the braking process, the relay piston pushes the second valve to open the passage from the second valve chamber to the second piston chamber.

8. The foot brake valve as described in claim 7, characterized in that, In the brake release state, the gas pressure in the main piston chamber pushes the main piston to reset, the first spring pushes the first valve to reset, and the gas pressure in the first piston chamber is discharged to the exhaust port of the foot brake valve. The gas pressure in the second piston chamber pushes the relay piston to reset, the second spring pushes the second valve to reset, and the gas in the first sub-chamber is discharged to the exhaust port. The gas in the second sub-chamber is discharged to the exhaust port through the first end of the differential pressure regulating chamber and the first sub-chamber.

9. The foot brake valve as described in claim 1, characterized in that, Also includes: A first housing and a second housing are sealed together, the first housing and the first end face of the relay piston defining the first piston chamber, the differential pressure regulating chamber being disposed in the second housing, and the second housing and the second end face of the relay piston defining the second piston chamber.

10. A pneumatic dual-circuit service braking system, characterized in that, The system is equipped with a foot brake valve as described in any one of claims 1 to 9, wherein the first piston chamber and the sub-chamber of the foot brake valve are respectively connected to the two circuits of the pneumatic dual-circuit service brake system.

Images