Relay valve and brake system

Abstract

The utility model relates to the technical field of braking, and provides a relay valve and a braking system. The first piston is arranged in the shell and divides an inner cavity of the shell into a control cavity and a brake cavity, the shell on the side of the control cavity is provided with a sinking table part, and the sinking table part extends into a piston cavity of the first piston; the second piston is arranged in the sinking table part and divides an inner cavity of the sinking table part into a sub-control cavity and a drainage cavity, the sub-control cavity is communicated with the control cavity, a first channel is arranged among the drainage cavity, the control cavity and the piston cavity, and a third channel is arranged between the piston cavity and an exhaust port of the brake cavity. According to the relay valve, automatic drainage can be achieved, and in the working process of the relay valve, water in the control cavity is automatically drained out of the valve through the first channel and the third channel along with movement and resetting of the first piston and the second piston.

Description

Technical Field

[0001] The utility model relates to the technical field of braking, and particularly to a relay valve and a braking system. Background Art

[0002] In the braking systems of heavy trucks such as commercial vehicles, relay valves are used to shorten the reaction time and the pressure build-up time.

[0003] The main structure and operating principle of the relay valve are as follows: A piston is arranged in the housing, dividing it into a control chamber and a braking chamber. The control chamber is connected to the master brake valve (foot brake valve), the air inlet of the braking chamber is connected to the air storage tank, the air outlet is connected to the rear braking chamber, and the exhaust port communicates with the atmosphere. In the non-braking state, the air outlet communicates with the exhaust port; in the braking state, the control gas from the master brake valve is input into the control chamber of the relay valve, pushing the piston to open the passage between the air inlet and the air outlet. Thus, the compressed air from the air storage tank quickly fills the rear braking chamber through the braking chamber of the relay valve, shortening the reaction time and the pressure build-up time and improving the braking efficiency.

[0004] The problems existing in the current relay valve are as follows: The control chamber is mostly designed as a closed cavity with a variable volume. Once there is water in the braking control pipeline, the water will enter and accumulate in the control chamber of the relay valve along with the control gas, causing problems such as damage to the components in the control chamber and freezing of water at low temperatures, which hinders the movement of the piston, and further leading to the failure of the relay valve to brake.

[0005] It should be noted that the information disclosed in the above background art section is only used to enhance the understanding of the background of the present utility model, and thus may include information that does not constitute the prior art known to those of ordinary skill in the art. Summary of the Utility Model

[0006] In view of this, the present utility model provides a relay valve and a braking system, which can achieve automatic drainage, and during the operation of the relay valve, the water in the control chamber of the relay valve is automatically drained out of the valve along with the movement and reset of the piston.

[0007] According to one aspect of the present utility model, a relay valve is provided, which includes a first piston arranged in a housing and dividing the inner cavity of the housing into a control chamber and a braking chamber, wherein: The housing on the control chamber side has a sunk part, and the sunk part extends into the piston cavity of the first piston; The relay valve further includes a second piston built in the sunk part and dividing the inner cavity of the sunk part into a sub-control chamber and a drainage chamber. The sub-control chamber communicates with the control chamber, a first channel is arranged between the drainage chamber and the control chamber and the piston cavity, and a third channel is arranged between the piston cavity and the exhaust port of the braking chamber.

[0008] In some embodiments, the relay valve includes two working states: a braking working state, in which it moves with the first piston and the second piston, the first channel is opened and the third channel is closed; a braking release working state, in which it resets with the first piston and the second piston, the third channel is opened and the first channel is closed.

[0009] In some embodiments, the first channel includes a first sub-channel disposed between the control chamber and the drain chamber, and a second sub-channel disposed between the drain chamber and the piston chamber; in the braking working state, first the first piston moves to open the first sub-channel, and then the second piston moves to close the third channel and open the second sub-channel; in the braking release working state, first the second piston resets to close the second sub-channel and open the third channel, and then the first piston resets to close the first sub-channel.

[0010] In some embodiments, in the braking working state, as the second piston moves, first the third channel is closed, and then the second sub-channel is opened; in the braking release working state, as the second piston resets, first the second sub-channel is closed, and then the third channel is opened.

[0011] In some embodiments, the second piston is configured with a return spring; the inner cavity of the sunk portion is provided with a stepped wall, the return spring is disposed inside the sunk portion, and both ends thereof respectively abut against the end face of the second piston and the end face of the stepped wall.

[0012] In some embodiments, the inner wall of the piston chamber is in slidable and sealed contact with the side wall of the sunk portion; the first sub-channel is disposed on the side wall of the sunk portion and extends obliquely downward from the control chamber to the drain chamber, and the first sub-channel is opened as the first piston descends and closed as the first piston ascends.

[0013] In some embodiments, in the braking working state, when the first piston descends to its lowest position, the first sub-channel is opened.

[0014] In some embodiments, the upper end of the second piston is in slidable and sealed contact with the inner wall of the sunk portion, the body portion of the second piston is concave to form the drain chamber between it and the inner wall of the sunk portion, and the lower end of the second piston is in slidable and sealed contact with the bottom of the sunk portion; the second sub-channel is disposed at the bottom of the sunk portion, and the second sub-channel is opened as the second piston descends and closed as the second piston ascends.

[0015] In some embodiments, the third channel is provided at the bottom of the first piston; as the second piston moves downward, the second piston contacts to close the third channel, and as the second piston moves upward, the second piston leaves to open the third channel.

[0016] In some embodiments, when releasing the braking working state, as the first piston resets, the third channel remains open.

[0017] In some embodiments, the bottom of the first piston is open and is embedded with a sealing ring, and the channel of the sealing ring forms the third channel.

[0018] In some embodiments, a control air passage communicating the control cavity with the sub-control cavity is provided on the side wall of the sunk portion, and the control air passage extends obliquely downward from the sub-control cavity to the control cavity.

[0019] In some embodiments, when releasing the braking working state, when the second piston moves upward to its highest position, the upper end surface of the second piston docks with the port of the control air passage.

[0020] In some embodiments, an end cover is provided at the port of the sunk portion, and the end cover seals the sub-control cavity.

[0021] According to another aspect of the present invention, a braking system is provided, and the braking system is configured with a relay valve as described in any of the above embodiments.

[0022] The beneficial effects of the present invention compared with the prior art at least include:

[0023] The first piston can move under the action of the air pressure in the control cavity, and the second piston can move under the action of the air pressure in the sub-control cavity. During the working process of the relay valve, the first piston and the third piston move and reset, so that the first channel and the third channel are opened at appropriate times. When the first channel is opened, the water in the control cavity flows to the piston cavity through the drainage cavity; when the third channel is opened, the water in the piston cavity is discharged out of the relay valve through the exhaust port.

[0024] Thus, the relay valve of the present invention can realize automatic drainage. During the working process of the relay valve, the water in the control cavity is automatically discharged out of the valve through the first channel and the third channel as the first piston and the second piston move and reset, effectively avoiding the braking failure of the relay valve and improving the service life of the relay valve and the braking safety of the braking system.

[0025] In addition, structures such as the second piston, the first channel, and the third channel added in the present utility model are all located inside the relay valve, without changing the pipeline connection of the relay valve; and according to the inherent working principle of the relay valve (the control air pressure in the control chamber drives the first piston to move), the present utility model uses the control air pressure to drive the second piston, so that the second piston cooperates with the first piston to change the on-off state of the first channel and the third channel, thereby realizing drainage of the control chamber without affecting the normal operation of the relay valve.

[0026] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the present utility model. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The accompanying drawings herein are incorporated into and constitute a part of the specification, showing embodiments consistent with the present utility model, and are used together with the specification to explain the principles of the present utility model. Obviously, the drawings described below are only some embodiments of the present utility model, and those of ordinary skill in the art can obtain other drawings based on these drawings without creative efforts.

[0028] Figure 1 Showing a schematic structural diagram of the relay valve in the embodiment of the present utility model, wherein the relay valve is in the initial state;

[0029] Figure 2 Showing a schematic structural diagram of the relay valve in the embodiment of the present utility model in the braking working state and when the first piston moves downward;

[0030] Figure 3 Showing a schematic structural diagram of the relay valve in the embodiment of the present utility model in the braking working state and when the second piston moves downward;

[0031] Figure 4 Showing a schematic structural diagram of the relay valve in the embodiment of the present utility model in the braking release working state and when the second piston moves upward. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0032] Example embodiments will now be described more fully with reference to the accompanying drawings. However, the example embodiments can be implemented in various forms and should not be construed as limited to the embodiments described herein. On the contrary, these embodiments are provided to make the present utility model more comprehensive and complete, and to fully convey the concept of the example embodiments to those skilled in the art.

[0033] The accompanying drawings are only schematic illustrations of the present utility model and are not necessarily drawn to scale. The same reference numerals in the drawings represent the same or similar parts, and thus their repeated description will be omitted.

[0034] The terms "first", "second" and similar terms used in the detailed description do not denote any order, quantity or importance, but are only used to distinguish different components. In the description of the present utility model, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", "top", "bottom", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present utility model. In addition, in the description of the present utility model, when it is said that a device is "connected" to another device, this includes not only the case of direct connection, but also the case of indirect connection through other elements.

[0035] It should be noted that, without conflict, the features in the embodiments of the present utility model and those in different embodiments can be combined with each other.

[0036] Figure 1 Schematically shows the structure of the relay valve in the embodiment of the present utility model. Refer to Figure 1 As shown, the relay valve provided in the embodiment of the present utility model includes a first piston 20 disposed in the housing 10 and separating the inner cavity of the housing 10 into a control chamber 11 and a brake chamber 12, wherein:

[0037] The housing 10 on the control chamber 11 side has a counterbore portion 100, and the counterbore portion 100 extends into the piston chamber 200 of the first piston 20;

[0038] The relay valve further includes a second piston 30 disposed in the counterbore portion 100 and separating the inner cavity of the counterbore portion 100 into a sub-control chamber 110 and a drain chamber 120. The sub-control chamber 110 is in communication with the control chamber 11, and a first passage P1 is provided between the drain chamber 120 and the control chamber 11 and the piston chamber 200. A third passage P3 is provided between the piston chamber 200 and the exhaust port 123 of the brake chamber 12.

[0039] The first piston 20 can move under the action of the air pressure in the control chamber 11, so that the relay valve exerts a braking effect. Specifically, the control chamber 11 is connected to the master brake valve, the air inlet of the brake chamber 12 is connected to the air storage tank, the air outlet is connected to the rear brake air chamber, and the exhaust port 123 communicates with the atmosphere; when the control gas from the master brake valve enters the control chamber 11, the control gas drives the first piston 20 to move, so that the first piston 20 pushes the valve 40 to connect the air inlet and the air outlet of the brake chamber 12, and thus the compressed air from the air storage tank quickly fills the rear brake air chamber through the brake chamber 12, realizing efficient braking.

[0040] The sub-control chamber 110 is connected to the control chamber 11 and can utilize the control air pressure during the operation of the relay valve to further drive the second piston 30 to move. Through the movement and reset of the first piston 20 and the second piston 30, the first channel P1 and the third channel P3 are opened at appropriate times. When the first channel P1 is opened, the water in the control chamber 11 flows through the drainage chamber 120 to the piston chamber 200; when the third channel P3 is opened, the water in the piston chamber 200 is discharged out of the relay valve through the exhaust port 123.

[0041] Therefore, the relay valve of the present utility model can achieve automatic drainage. During the operation of the relay valve, the water in the control chamber 11 is automatically discharged out of the valve through the first channel P1 and the third channel P3 along with the movement and reset of the first piston 20 and the second piston 30, effectively avoiding the braking failure of the relay valve and improving the service life of the relay valve and the braking safety of the braking system.

[0042] In addition, the structures such as the second piston 30, the first channel P1, and the third channel P3 added in the present utility model are all located inside the relay valve and do not change the pipeline connection of the relay valve; and according to the inherent working principle of the relay valve (the control air pressure in the control chamber 11 drives the first piston 20 to move), the present utility model utilizes the control air pressure to drive the second piston 30, so that the second piston 30 cooperates with the first piston 20 to change the on-off of the first channel P1 and the third channel P3, thereby realizing the drainage of the control chamber 11 without affecting the normal operation of the relay valve.

[0043] In some embodiments, the relay valve has two working states: the braking working state, with the first piston 20 and the second piston 30 moving, the first channel P1 is opened and the third channel P3 is closed; the braking release working state, with the first piston 20 and the second piston 30 resetting, the third channel P3 is opened and the first channel P1 is closed.

[0044] Among them, the vehicle equipped with the relay valve has a braking stage and a braking release stage; during the braking stage of the vehicle, the relay valve is in the braking working state; during the braking release stage of the vehicle, the relay valve is in the braking release working state.

[0045] When the relay valve is in the braking working state, under the action of the control air pressure, with the movement of the first piston 20 and the second piston 30, the first channel P1 is opened, so that the water in the control chamber 11 flows through the drainage chamber 120 to the piston chamber 200; and the third channel P3 is closed in the braking working state, which can avoid the gas leakage in the control chamber 11 from affecting the braking performance of the relay valve.

[0046] When the relay valve is in the brake release working state, the control air pressure in the control chamber 11 and the sub-control chamber 110 decreases, then the first piston 20 and the second piston 30 reset, causing the third passage P3 to open, so that the water in the piston chamber 200 is discharged out of the relay valve through the exhaust port 123; and in the brake release working state, the first passage P1 is closed to avoid affecting the sealing performance of the control chamber 11.

[0047] Figure 1 The shown relay valve is in the initial state; Figure 2 Schematically shows the structure of the relay valve in the braking working state and when the first piston moves downward, Figure 3 Schematically shows the structure of the relay valve in the braking working state and when the second piston moves downward, Figure 4 Schematically shows the structure of the relay valve in the brake release working state and when the second piston moves upward.

[0048] Combined with Figures 1 to 4 As shown, in some embodiments, the first passage P1 includes a first sub-passage P11 provided between the control chamber 11 and the drainage chamber 120, and a second sub-passage P12 provided between the drainage chamber 120 and the piston chamber 200; in the braking working state, first the first piston 20 moves to open the first sub-passage P11, and then the second piston 30 moves to close the third passage P3 and open the second sub-passage P12; in the brake release working state, first the second piston 30 resets to close the second sub-passage P12 and open the third passage P3, and then the first piston 20 resets to close the first sub-passage P11.

[0049] Through the first sub-passage P11 and the second sub-passage P12, the communication between the control chamber 11, the drainage chamber 120 and the piston chamber 200 is realized.

[0050] In the braking working state, combined with Figure 1 、 Figure 2 and Figure 3 As shown, first the first piston 20 moves to open the first sub-passage P11, so that the water in the control chamber 11 is discharged to the drainage chamber 120, and then the second piston 30 moves to open the second sub-passage P12, so that the water in the drainage chamber 120 is discharged to the piston chamber 200. The movement of the second piston 30 also closes the third passage P3 to avoid leakage of the control air pressure, and further avoid affecting the braking performance of the relay valve.

[0051] Among them, through the structural cooperation design of the second piston 30 and the third passage P3, the closing of the third passage P3 and the opening of the second sub-passage P12 can be realized synchronously, or the third passage P3 is closed first and then the second sub-passage P12 is opened.

[0052] In the brake release working state, combined with Figure 3 、 Figure 4 and Figure 1As shown, first, the second piston 30 is reset ( Figure 4 During the reset process of the second piston 30 shown schematically, it has not been fully reset), the third channel P3 is opened, so that the water in the piston chamber 200 is drained out of the valve. The reset of the second piston 30 also closes the second sub-channel P12 to avoid affecting the sealing performance of the control chamber 11. Then, the first piston 20 is reset and the first sub-channel P11 is closed, so that the relay valve as a whole is reset to the initial state for subsequent braking response.

[0053] Among them, through the structural cooperation design of the second piston 30 and the third channel P3, the closing of the third channel P3 and the opening of the second sub-channel P12 in the braking working state can be realized synchronously, the closing of the second sub-channel P12 and the opening of the third channel P3 in the braking release working state can be realized synchronously, or the third channel P3 is closed first and then the second sub-channel P12 is opened in the braking working state, and the second sub-channel P12 is closed first and then the third channel P3 is opened in the braking release working state.

[0054] In some embodiments, in the braking working state, as the second piston 30 moves, the third channel P3 is closed first and then the second sub-channel P12 is opened; in the braking release working state, as the second piston 30 is reset, the second sub-channel P12 is closed first and then the third channel P3 is opened.

[0055] In this way, in the braking working state and the braking release working state, first ensure the sealing performance of the control chamber 11 and avoid the communication between the control chamber 11 and the exhaust port 123, and then drain the water to avoid the leakage of the control air pressure and affect the braking performance of the relay valve.

[0056] Continuing to combine with Figures 1 to 4 As shown, in some embodiments, the second piston 30 is provided with a return spring 33; the inner cavity of the sunk part 100 is provided with a stepped wall 101, and the return spring 33 is placed inside the sunk part 100 and its two ends respectively abut against the end face of the second piston 30 and the end face of the stepped wall 101.

[0057] The return spring 33 is sleeved outside the second piston 30 and abuts and cooperates with the end face of the second piston 30 and the end face of the stepped wall 101 of the sunk part 100, so that the return spring 33 is compressed in the braking working state and restored in the braking release working state to push the second piston 30 to reset.

[0058] Specifically, in the braking working state, the return spring 33 provides a certain resistance to the second piston 30, causing the second piston 30 to move downward later than the first piston 20, so as not to affect the response speed of the first piston 20, ensuring that the braking performance of the relay valve is not affected, and facilitating the drainage from the control chamber 11 to the drain chamber 120 and from the drain chamber 120 to the piston chamber 200; in the braking release working state, the return spring 33 provides a certain driving force to the second piston 30, enabling the second piston 30 to overcome the resistance (such as the resistance from the sealing ring 60 to be described below) and reset, and causing the second piston 30 to move upward earlier than the first piston 20, facilitating the drainage from the piston chamber 200 to the exhaust port 123 and preventing the water in the piston chamber 200 from being unable to drain smoothly due to the first piston 20 resetting first.

[0059] The spring force of the return spring 33 can be set as required. In a preferred case, the spring force of the return spring 33 is such that the second piston 30 does not move when the control air pressure in the control chamber 11 is small, and the second piston 30 participates in drainage only when the control air pressure in the control chamber 11 reaches a certain value; in this way, the service life of the second piston 30 and its mating components is improved, and the water accumulated in the control chamber 11 can also be discharged in a timely manner.

[0060] The first piston 20 may or may not be configured with a return spring. If the first piston 20 is not configured with a return spring, in the braking release working state, when the control air pressure in the control chamber 11 decreases, the first piston 20 can be reset under the action of the air pressure in the brake chamber 12. If the first piston 20 is configured with a return spring, the spring force of the return spring of the first piston 20 is less than the spring force of the return spring 33 of the second piston 30.

[0061] Refer to Figure 2 As shown, in some embodiments, the inner wall of the piston chamber 200 is in slidable sealing contact with the side wall of the sunk portion 100; the first sub-channel P11 is provided on the side wall of the sunk portion 100 and extends obliquely downward from the control chamber 11 to the drain chamber 120. The first sub-channel P11 is opened as the first piston 20 moves downward and closed as the first piston 20 moves upward.

[0062] The slidable sealing contact can be a small clearance / transition fit for sliding and is sealed by structures such as lubricating oil / sealing rings. For example, the inner wall of the piston chamber 200 is in clearance fit with the side wall of the sunk portion 100 and is in sealed contact through the first sealing ring 51.

[0063] The first sub-channel P11 extends obliquely downward. When the relay valve is vertically assembled, when the first piston 20 moves downward relative to the sunk platform portion 100 until the control chamber 11 communicates with the drain chamber 120, the first sub-channel P11 opens, and water automatically drains from the control chamber 11 to the drain chamber 120 under the action of gravity. When the first piston 20 moves upward relative to the sunk platform portion 100 to reset, the first piston 20 gradually seals the opening of the first sub-channel P11 leading to the control chamber 11, and then the first sub-channel P11 closes.

[0064] In some embodiments, in the braking working state, when the first piston 20 moves downward to its lowest position, the first sub-channel P11 opens.

[0065] In this way, on the one hand, it avoids the premature opening of the first sub-channel P11 from affecting the movement of the second piston 30, and on the other hand, it ensures that the water in the control chamber 11 is discharged through the first sub-channel P11, avoiding water accumulation in the control chamber 11.

[0066] Refer to Figure 3 As shown, in some embodiments, the upper end of the second piston 30 is in slidable and sealed contact with the inner wall of the sunk platform portion 100. The body portion of the second piston 30 is concave, and a drain chamber 120 is formed between the second piston 30 and the inner wall of the sunk platform portion 100. The lower end of the second piston 30 is in slidable and sealed contact with the bottom of the sunk platform portion 100. The second sub-channel P12 is provided at the bottom of the sunk platform portion 100, and the second sub-channel P12 opens as the second piston 30 moves downward and closes as the second piston 30 moves upward.

[0067] As described above, the slidable and sealed contact can be a small clearance / transition fit for sliding and is sealed through structures such as lubricating oil / sealing rings. For example, the upper end of the second piston 30 can be in clearance fit with the inner wall of the sunk platform portion 100 and is in sealed contact through the second sealing ring 52. The lower end of the second piston 30 can be in clearance fit with the bottom of the sunk platform portion 100 and is in sealed contact through the third sealing ring 53.

[0068] The second sub-channel P12 is provided at the bottom of the sunk platform portion 100. When the relay valve is vertically assembled, when the second piston 30 moves downward relative to the sunk platform portion 100 to open the second sub-channel P12, water drains from the drain chamber 120 to the piston chamber 200 under the action of gravity. When the second piston 30 moves upward relative to the sunk platform portion 100 to reset, the second sub-channel P12 closes.

[0069] Refer to Figure 4 As shown, in some embodiments, the third channel P3 is provided at the bottom of the first piston 20. As the second piston 30 moves downward, the second piston 30 contacts to close the third channel P3. As the second piston 30 moves upward, the second piston 30 moves away to open the third channel P3.

[0070] The third passage P3 is provided at the bottom of the first piston 20. When the relay valve is vertically assembled, when the second piston 30 moves downward to open the third passage P3, water is discharged from the piston chamber 200 to the exhaust port 123 under the action of gravity, and then discharged outside the relay valve. The second piston 30 can close the third passage P3 by sealingly contacting the third passage P3 and open the third passage P3 by moving upward and away.

[0071] Combined Figure 4 with Figure 1 As shown, in some embodiments, when the braking working state is released and the first piston 20 resets, the third passage P3 remains open.

[0072] In this way, when the relay valve as a whole resets to the initial state, there is no contact interference between the first piston 20 and the newly added structures such as the second piston 30, so as not to affect the response speed of the first piston 20 in the braking working state, and further not to affect the braking performance such as the reaction time / building pressure time of the relay valve, enabling the relay valve to have the automatic drainage function while still being able to normally exert the braking effect.

[0073] In some embodiments, the bottom of the first piston 20 is open and a sealing ring 60 is embedded. The passage of the sealing ring 60 forms the third passage P3.

[0074] The outer ring of the sealing ring 60 is in sealing contact with the bottom of the first piston 20; the second piston 30 can move downward to be in sealing contact with the inner ring of the sealing ring 60 to close the third passage P3, and can move upward and away from the sealing ring 60 to open the third passage P3.

[0075] In other embodiments, the sealing ring 60 may not be provided, and the opening and closing of the third passage P3 are achieved by the cooperation between the end of the second piston 30 and the bottom opening of the first piston 20.

[0076] Referring to Figure 1 As shown, in some embodiments, a control air passage 160 communicating the control chamber 11 and the sub-control chamber 110 is provided on the side wall of the sunk portion 100, and the control air passage 160 extends obliquely downward from the sub-control chamber 110 to the control chamber 11.

[0077] Through the control air passage 160, the communication between the sub-control chamber 110 and the control chamber 11 is achieved, so as to drive the first piston 20 and the second piston 30 by using the control air pressure according to the inherent action principle of the relay valve, and enable the second piston 30 to cooperate with the first piston 20 to drain the control chamber 11 without affecting the normal operation of the relay valve. The control air passage 160 extends obliquely downward, which helps the water in the sub-control chamber 110 to flow along the control air passage 160 to the control chamber 11, and then be discharged outside the relay valve through the first passage P1 and the third passage P3.

[0078] In some embodiments, when the braking operation state is released, when the second piston 30 moves upward to its highest position, the upper end surface of the second piston 30 is docked with the port of the control air passage 160.

[0079] In this way, on the one hand, the sub-control chamber 110 is kept in communication with the control chamber 11 so that the braking operation state can drive the movement of the second piston 30 by using the control air pressure. On the other hand, the accumulation of water in the sub-control chamber 110 is avoided, and the water in the sub-control chamber 110 flows along the control air passage 160 to the control chamber 11.

[0080] In some embodiments, an end cover 70 is provided at the port of the sunk portion 100, and the end cover 70 seals the sub-control chamber 110.

[0081] The end cover 70 can be in sealing contact with the port of the sunk portion 100 through the fourth sealing ring 77 to prevent the leakage of the control air pressure and affect the braking performance of the relay valve.

[0082] The embodiment of the present invention also provides a braking system, and the braking system is configured with a relay valve as described in any of the above embodiments.

[0083] Combined with Figures 1 to 4 As shown, the braking system is configured with the above relay valve, which can achieve rapid braking while automatically discharging the water in the control chamber 11, improving the service life of the relay valve, and ensuring the safety and reliability of the braking system.

[0084] Specifically, during the braking process, the control air pressure enters the control chamber 11 from the master brake valve, pushing the first piston 20 downward to open the valve 40, so that the air inlet of the brake chamber 12 is communicated with the air outlet, and thus the braking air pressure from the air storage tank is output to the rear braking actuator through the brake chamber 12; at this time, the first sub-channel P11 between the control chamber 11 and the drain chamber 120 is opened. When the brake chamber 12 receives the control air pressure, the sub-control chamber 110 also receives the control air pressure. When the control air pressure in the sub-control chamber 110 is greater than the acting force of the return spring 33, the second piston 30 is pushed downward by the control air pressure. During the downward movement of the second piston 30, it first contacts the sealing ring 60 to form a seal to close the third channel P3, and then continues to move downward to disengage from the third sealing ring 53 to open the second sub-channel P12, so that the water in the control chamber 11 is discharged to the piston chamber 200 through the drain chamber 120.

[0085] During the braking release process, as the control air pressure decreases, the second piston 30 is pushed upward by the return spring 33. During the upward movement, the second piston 30 first contacts and seals with the third sealing ring 53, and then disengages from the sealing ring 60. At this time, the water in the piston chamber 200 is discharged outside the relay valve. Further, as the control air pressure continues to decrease, the first piston 20 is reset, and thus the relay valve as a whole returns to its initial state.

[0086] The above content is a further detailed description of the present utility model in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present utility model is only limited to these descriptions. For those of ordinary skill in the technical field to which the present utility model belongs, without departing from the concept of the present utility model, several simple deductions or substitutions can still be made, and all should be regarded as belonging to the protection scope of the present utility model.

Claims

1. A relay valve, comprising a first piston disposed in a housing and dividing an inner cavity of the housing into a control cavity and a brake cavity, characterized in that: The housing on the control chamber side has a sink portion, and the sink portion extends into the piston chamber of the first piston; The relay valve also includes a second piston built into the sink portion and dividing the inner cavity of the sink portion into a sub-control cavity and a drainage cavity, the sub-control cavity is connected to the control cavity, a first channel is arranged between the drainage cavity, the control cavity and the piston cavity, and a third channel is arranged between the piston cavity and the exhaust port of the brake cavity.

2. The relay valve according to claim 1, characterized in that: The relay valve includes two working states: In the braking working state, as the first piston and the second piston move, the first channel is opened and the third channel is closed; The braking working state is released, and as the first piston and the second piston are reset, the third channel is opened and the first channel is closed.

3. The relay valve according to claim 2, characterized in that: The first channel includes a first sub-channel disposed between the control chamber and the drainage chamber, and a second sub-channel disposed between the drainage chamber and the piston chamber; In the braking working state, the first piston moves first to open the first sub-channel, and then the second piston moves to close the third channel and open the second sub-channel; In the brake release working state, the second piston is reset first to close the second sub-channel and open the third channel, and then the first piston is reset to close the first sub-channel.

4. The relay valve according to claim 3, characterized in that: In the braking working state, as the second piston moves, the third channel is closed first, and then the second sub-channel is opened; In the brake release working state, as the second piston is reset, the second sub-channel is closed first, and then the third channel is opened.

5. The relay valve according to claim 3, characterized in that: The inner wall of the piston chamber is in slidable sealing contact with the side wall of the sinking portion; The first sub-channel is arranged on the side wall of the sink portion, and extends obliquely downward from the control chamber to the drainage chamber. The first sub-channel opens as the first piston moves downward, and closes as the first piston moves upward.

6. The relay valve according to claim 5, characterized in that: In the braking working state, when the first piston descends to its lowest position, the first sub-channel is opened.

7. The relay valve according to claim 3, characterized in that: The upper end of the second piston is in slidable sealing contact with the inner wall of the sinking platform, the body of the second piston is concave, and the drainage cavity is formed between the body and the inner wall of the sinking platform, and the lower end of the second piston is in slidable sealing contact with the bottom of the sinking platform; The second sub-channel is arranged at the bottom of the sinking platform, and the second sub-channel is opened as the second piston moves downward and is closed as the second piston moves upward.

8. The relay valve according to claim 3, characterized in that: The third channel is arranged at the bottom of the first piston; As the second piston moves downward, the second piston contacts to close the third channel, and as the second piston moves upward, the second piston leaves to open the third channel.

9. The relay valve according to claim 8, characterized in that: In the brake release working state, as the first piston is reset, the third channel remains open.

10. The relay valve according to claim 8, characterized in that: The bottom of the first piston is open and a sealing ring is embedded therein, and a channel of the sealing ring forms the third channel.

11. The relay valve according to claim 1, characterized in that: The second piston is provided with a return spring; The inner cavity of the sinking part is provided with a step wall, the return spring is built in the sinking part, and two ends of the return spring respectively abut against the end surface of the second piston and the end surface of the step wall.

12. The relay valve according to claim 1, characterized in that: A control air passage connecting the control chamber and the sub-control chamber is disposed on the side wall of the sinking platform, and the control air passage extends obliquely downward from the sub-control chamber to the control chamber.

13. The relay valve according to claim 12, characterized in that: When the brake working state is released, when the second piston moves upward to its highest position, the upper end surface of the second piston docks with the port of the control airway.

14. The relay valve according to claim 1, characterized in that: The port of the sinking platform is provided with an end cover, and the end cover seals the sub-control cavity.

15. A braking system, characterized in that: The brake system is equipped with a relay valve as described in any one of claims 1-14.

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