Parking relay valve and parking brake system

Abstract

The application discloses a parking relay valve and a parking brake system and belongs to the technical field of vehicle brake equipment. The parking relay valve comprises a valve shell, a main piston and a supply piston. The valve shell is provided with a parking cavity, a control cavity and a pop-out function cavity which are sequentially distributed. The main piston comprises a piston rod and a piston block. The piston rod is arranged in the control cavity and the pop-out function cavity. The piston block is arranged in the control cavity. A main spring acting on the piston block is arranged in the control cavity. The parking cavity is provided with a first port connected with a PB system. The control cavity is divided into a PB brake sub-cavity and a PB control sub-cavity by the piston block. A pop-out slider sleeved on the piston rod and a pop-out spring acting on the pop-out slider are arranged in the pop-out function cavity. The pop-out slider can drive the main piston to move synchronously. The pop-out function cavity is divided into an ambient pressure sub-cavity and a pop-out control sub-cavity by the pop-out slider. The automatic brake is realized by the pop-out function cavity when the brake circuit pressure is reduced to a certain degree, so that the vehicle can stop moving in time, and the safety of the vehicle during driving is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of vehicle brake equipment, in particular to a parking relay valve, and the present application also relates to a parking brake system using the parking relay valve. BACKGROUND

[0002] For safety, the brake of the existing large vehicle has three states of driving state, service brake state and parking brake state, and the brake circuit for realizing the brake is generally provided with main and auxiliary two branches, when the main brake circuit is abnormal or fails, the auxiliary brake circuit compensates the main brake, so that the vehicle can be smoothly braked. The relay valve is an important component of the air brake system of the vehicle, and in the air brake system of the large vehicle, the relay valve plays a role in shortening the reaction time and the pressure building time. The structure of the existing relay valve is relatively complex, when the brake system of the vehicle is abnormal and causes the pressure of the brake circuit to drop, the structure for realizing self-braking through the relay valve is relatively complex, and cannot quickly respond to realize the self-braking function. SUMMARY

[0003] In order to solve the above-mentioned shortcomings and deficiencies in the prior art, the present application provides a parking relay valve, which is provided with a pop-out function cavity, when the maximum pressure of the service brake circuit is too small, the PB cavity of the brake cylinder is communicated with the exhaust channel of the supply piston, the purpose of self-braking is realized, and the driving safety of the vehicle is improved.

[0004] In order to realize the above technical purpose, the parking relay valve provided by the present application is used for air brake of the vehicle, which comprises a valve housing, a main piston and a supply piston,

[0005] The valve housing is provided with a parking cavity, a control cavity and a pop-out function cavity which are sequentially distributed;

[0006] The main piston comprises a piston rod and a piston block arranged at one end of the piston rod, the piston rod is arranged in the control cavity and the pop-out function cavity, the piston block is arranged in the control cavity, and a main spring acting on the piston block is arranged in the control cavity;

[0007] The parking cavity is provided with a first port connected with the PB system;

[0008] The control cavity is divided into a PB brake sub-cavity and a PB control sub-cavity by the piston block, the PB brake sub-cavity is provided with a second port connected with the PB cavity of the brake cylinder, and the PB control sub-cavity is provided with a third port connected with the parking control member;

[0009] The supply piston passes through the parking cavity and extends into the PB brake sub-cavity, the supply piston is used for controlling the on-off between the parking cavity and the PB brake sub-cavity, and is provided with an exhaust channel which can be communicated with the PB brake sub-cavity, and a secondary spring acting on the supply piston is arranged in the parking cavity;

[0010] The pop-out function cavity is provided with a pop-out slider sleeved on the piston rod and a pop-out spring acting on the pop-out slider, the pop-out slider can drive the main piston to move synchronously, the pop-out function cavity is divided into an ambient pressure sub-cavity and a pop-out control sub-cavity by the pop-out slider, the ambient pressure sub-cavity is provided with a fourth port in communication with external air, and the pop-out control sub-cavity is provided with a fifth port connected with the service brake circuit;

[0011] When the pressure of the PB control sub-cavity decreases, the main spring drives the piston block to move, so that the PB cavity of the brake cylinder is in communication with the exhaust channel of the supply piston, and braking is realized.

[0012] When the pressure of the PB control sub-cavity increases, the piston block drives the supply piston to move, so that the PB system is in communication with the PB cavity of the brake cylinder, and releasing is realized.

[0013] When the maximum pressure of the service brake circuit is as low as a first preset value, the pop-out spring drives the main piston to move through the pop-out slider to release the supply piston, so that the PB cavity of the brake cylinder is in communication with the exhaust channel of the supply piston, and self-braking is realized.

[0014] Preferably, the part of the piston rod in the pop-out function cavity is provided with a protruding part capable of abutting against the pop-out slider.

[0015] Preferably, the first preset value is 40 PSI.

[0016] Preferably, the valve housing is provided with a mixing function cavity,

[0017] The piston rod passes through the mixing function cavity, the mixing function cavity is provided with a proportional slider sleeved on the piston rod and a proportional spring acting on the proportional slider, and the proportional slider can drive the main piston to move synchronously.

[0018] The mixing function cavity is divided into a proportional control sub-cavity and a main brake sub-cavity by the proportional slider, the proportional control sub-cavity is provided with a sixth port connected with the auxiliary service brake circuit, and the main brake sub-cavity is provided with a seventh port connected with the main brake circuit.

[0019] When the maximum pressure of the main brake circuit is as low as a second preset value, the proportional spring drives the main piston to move through the proportional slider to release the supply piston, and the PB cavity of the brake cylinder is depressurized to balance the pressure of the PB system through the exhaust channel of the supply piston.

[0020] Preferably, the second preset value is 60 PSI.

[0021] Preferably, the part of the piston rod in the mixing function cavity is provided with a ring part capable of abutting against the proportional slider.

[0022] The application further provides a parking brake system for air braking of a self-powered vehicle, which comprises the parking relay valve described above.

[0023] The application also provides a parking brake system for air brake of a vehicle with a trailer, which comprises the two parking relay valves described above, one of which is arranged on the brake circuit of the trailer and the other of which is arranged on the brake circuit of the vehicle.

[0024] After the above technical scheme is adopted, the application has the following advantages:

[0025] 1. The parking relay valve provided by the application has the valve housing provided with a parking cavity, a control cavity and a pop-out function cavity, the environment pressure sub-cavity of the pop-out function cavity is communicated with external air, and the pop-out control sub-cavity is connected with the service brake circuit. When the service brake circuit fails to cause the maximum pressure to be as low as a first preset value, the pop-out spring acts on the pop-out slider to make the pop-out slider drive the main piston to release the supply piston, so that the PB cavity of the brake cylinder is communicated with the discharge passage of the supply piston, the pressure of the PB cavity of the brake cylinder is reduced, the brake is self-braked, and the purpose of automatic parking is achieved. The pop-out function cavity realizes self-braking when the pressure of the brake circuit is reduced to a certain degree, so that the vehicle can be stopped in time, and the safety during vehicle driving is improved.

[0026] 2. Further, the valve housing is provided with a mixing function cavity. When the main brake circuit fails to cause the maximum pressure to be as low as a second preset value, the proportional spring acts on the proportional slider to make the pop-out slider drive the main piston to move, the main piston releases the supply piston, the PB cavity of the brake cylinder is communicated with the discharge passage of the supply piston, the pressure of the PB cavity is reduced to balance with the supply pressure of the PB system, so that the brake system can brake according to the pressure condition of the auxiliary brake circuit, and the pressure of the auxiliary brake circuit meets the braking requirement. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 FIG. 1 is a schematic diagram of the internal structure of the I-type parking relay valve in Example 1;

[0028] Figure 2 FIG. 2 is a schematic diagram of the internal structure of the II-type parking relay valve in Example 2;

[0029] Figure 3 FIG. 3 is a schematic diagram of the parking brake system in Example 3;

[0030] Figure 4 FIG. 4 is a schematic diagram of the parking brake system in Example 4.

[0031] In the diagram, 100A-Type I parking relay valve, 100B-Type II parking relay valve, 110-valve body, 120-main piston, 121-piston rod, 122-piston block, 123-protrusion, 124-convex ring, 130-supply piston, 131-discharge channel, 140-parking chamber, 141-first port, 150-control chamber, 151-PB brake chamber, 152-PB control chamber, 153-second port, 154-third port. 160 - Pop-up functional chamber, 161 - Ambient pressure chamber, 162 - Pop-up control chamber, 163 - Pop-up slider, 164 - Fourth port, 165 - Fifth port, 171 - Main spring, 172 - Secondary spring, 173 - Pop-up spring, 174 - Proportional spring, 180 - Connecting channel, 190 - Mixed functional chamber, 191 - Proportional control chamber, 192 - Main braking chamber, 193 - Proportional slider, 194 - Sixth port, 195 - Seventh port. Detailed Implementation

[0032] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. It should be understood that the terms "upper," "lower," "left," "right," "longitudinal," "lateral," "inner," "outer," "vertical," "horizontal," "top," and "bottom," etc., which indicate orientation or positional relationships, are based solely on the orientation or positional relationships shown in the accompanying drawings and are used only for the convenience of describing the present invention and simplifying the description. They do not indicate or imply that the device / component referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as limiting the present invention.

[0033] Example 1

[0034] like Figure 1 As shown, the Type I parking relay valve 100A provided in Embodiment 1 of the present invention is used for the air braking of a vehicle, and includes a valve housing 110, a main piston 120, and a supply piston 130.

[0035] The valve housing 110 is provided with a parking chamber 140, a control chamber 150 and an ejection function chamber 160 arranged sequentially from bottom to top;

[0036] The main piston 120 includes a piston rod 121 and a piston block 122 disposed at one end of the piston rod 121. The piston rod 121 passes through the control cavity 150 and the ejection function cavity 160. The piston block 122 is disposed in the control cavity 150. A main spring 171 acting on the piston block 122 is provided in the control cavity 150.

[0037] The parking chamber 140 is provided with a first port 141 for connection to the PB system;

[0038] The control cavity 150 is divided into a PB brake sub-cavity 151 and a PB control sub-cavity 152 by the piston block 122, the PB brake sub-cavity 151 is provided with a second port 153 connected with the PB cavity of the brake cylinder, and the PB control sub-cavity 152 is provided with a third port 154 connected with the parking control member;

[0039] The supply piston 130 penetrates the parking cavity 140 and extends into the PB brake sub-cavity 151, the supply piston 130 is used for controlling the on-off between the parking cavity 140 and the PB brake sub-cavity 151 and is provided with a discharge passage 131 in communication with the PB brake sub-cavity 151, and the parking cavity 140 is provided with a secondary spring 172 acting on the supply piston 130;

[0040] The pop-up function cavity 160 is provided with a pop-up slider 163 sleeved on the piston rod 121 and a pop-up spring 173 acting on the pop-up slider 163, the pop-up slider 163 can drive the main piston 120 to move synchronously, the pop-up function cavity 160 is divided into an ambient pressure sub-cavity 161 and a pop-up control sub-cavity 162 by the pop-up slider 163, the ambient pressure sub-cavity 161 is provided with a fourth port 164 in communication with the external air, and the pop-up control sub-cavity 162 is provided with a fifth port 165 connected with the service brake circuit;

[0041] When the pressure of the PB control sub-cavity 152 decreases, the main spring 171 drives the piston block 122 to move upward, so that the PB cavity of the brake cylinder is in communication with the discharge passage 131 of the supply piston 130, and braking is realized;

[0042] When the pressure of the PB control sub-cavity 152 increases, the piston block 122 drives the supply piston 130 to move downward, so that the PB system is in communication with the PB cavity of the brake cylinder, and releasing is realized;

[0043] When the maximum pressure of the service brake circuit is as low as a first preset value, the pop-up spring 173 drives the main piston 120 to move upward through the pop-up slider 163 and releases the supply piston 130, so that the PB cavity of the brake cylinder is in communication with the discharge passage 131 of the supply piston 130, and self-braking is realized.

[0044] In order to make the pop-up slider 163 smoothly drive the main piston 120 to move upward and release the supply piston 130, the part of the piston rod 121 located in the pop-up function cavity 160 is provided with a protruding part 123 in abutting cooperation with the pop-up slider 163. In the embodiment, the pop-up slider 163 is provided with a hole through which the upper end of the piston rod 121 penetrates, and the top end of the piston rod 121 is provided with a protruding ring forming the protruding part 123, and the outer diameter of the protruding ring is greater than the inner diameter of the hole of the pop-up slider 163 through which the piston rod 121 penetrates.

[0045] The type I parking relay valve 100A of the embodiment is mainly used for braking of a trailer, and the air pressure of a service brake circuit is consistent with that of a service brake circuit in a towing vehicle. The air pressure of the service brake circuit includes that of a main service brake circuit and that of a secondary service brake circuit. The first preset value is specifically 40 PSI.

[0046] The parking chamber 140 and the PB brake sub-chamber 151 of the control chamber 150 are provided with a communication passage 180, and the supply piston 130 is partially located in the communication passage 180. The supply piston 130 can move downward to leave the valve housing 110 under the abutting action of the main piston 120. At this time, the parking chamber 140 and the PB brake sub-chamber 151 can be communicated through the communication passage 180, so that the first port 141 and the second port 153 are communicated, and the supply pressure of the PB system can be output to the PB chamber of the brake cylinder through the first port 141, the parking chamber 140, the communication passage 180, the PB brake sub-chamber 151 and the second port 153. When the pressure of the first port 141 and the second port 153 reaches equilibrium, the supply piston 130 is reset under the action of the secondary spring 172, the supply piston 130 abuts against the valve housing 110, the communication passage 180 is closed by the supply piston 130, the PB system and the PB chamber of the brake cylinder are disconnected, and the switching from parking to release is realized.

[0047] When parking is needed, the air in the PB control sub-chamber 152 is discharged, the air pressure of the PB control sub-chamber 152 is reduced, the main piston 120 moves upward under the elastic force of the main spring 171, the main piston 120 releases the supply piston 130, the PB brake sub-chamber 151 and the discharge passage 131 of the supply piston 130 are communicated, the PB chamber of the brake cylinder is communicated with the discharge passage 131 through the first port 141 and the PB brake sub-chamber 151, and the air in the PB chamber of the brake cylinder can be discharged through the first port 141, the PB brake sub-chamber 151 and the discharge passage 131. The air pressure of the PB chamber of the brake cylinder is reduced. When the air pressure in the PB brake sub-chamber 151 is reduced to the main piston 120 falling to contact the supply piston 130, the air pressure in the PB chamber of the brake cylinder reaches the minimum. At this time, the brake holds the wheel, and the switching from release to parking is realized.

[0048] When the air pressure of the service brake circuit is reduced to the first preset value, it indicates that the service brake circuit is malfunctioning, at this time, the air pressure in the pop-up control sub-cavity 162 is reduced, the pop-up spring 173 acts on the pop-up slider 163, the pop-up slider 163 drives the main piston 120 to move upward to release the supply piston 130, the PB brake sub-cavity 151 and the exhaust passage 131 of the supply piston 130 are communicated, the PB cavity of the brake cylinder can be communicated through the first port 141, the PB brake sub-cavity 151 and the exhaust passage 131, the air in the PB cavity of the brake cylinder can be exhausted through the first port 141, the PB brake sub-cavity 151 and the exhaust passage 131, and the air pressure in the PB cavity of the brake cylinder is reduced. When the air pressure in the PB brake sub-cavity 151 is reduced to the main piston 120 falls to contact the supply piston 130, the air pressure in the PB cavity of the brake cylinder reaches the minimum, at this time, the brake holds the wheel, the brake implements self-braking, and the purpose of automatic parking is achieved. Through the pop-up function cavity 160, self-braking is realized when the brake circuit pressure is reduced to a certain degree, so that the vehicle can stop moving in time and the safety of the vehicle during driving is improved.

[0049] It can be understood that the first preset value can also be slightly greater than 40 PSI.

[0050] Embodiment two

[0051] In combination Figure 2 , the embodiment discloses a type II parking relay valve 100B, and the type II parking relay valve 100B of the embodiment is additionally provided with a mixed function cavity 190 based on the structure of the first embodiment, and the mixed function cavity 190 is located between the control cavity 150 and the pop-up function cavity 160. In the embodiment, the piston rod 121 of the main piston 120 penetrates through the mixed function cavity 190, the mixed function cavity 190 is provided with a proportional slider 193 sleeved on the piston rod 121 and a proportional spring 174 acting on the proportional slider 193, and the proportional slider 193 can drive the main piston 120 to move upward synchronously. The mixed function cavity 190 is divided into a proportional control sub-cavity 191 and a main brake sub-cavity 192 by the proportional slider 193, the proportional control sub-cavity 191 is provided with a sixth port 194 connected with a secondary service brake circuit, and the main brake sub-cavity 192 is provided with a seventh port 195 connected with a main brake circuit. When the maximum pressure of the main brake circuit is reduced to a second preset value, the proportional spring 174 drives the main piston 120 to move upward and release the supply piston 130 through the proportional slider 193, and the PB cavity of the brake cylinder is depressurized to balance with the supply pressure of the PB system through the exhaust passage 131 of the supply piston 130.

[0052] The type II parking relay valve 100B of the embodiment is mainly used for air braking of a self-powered vehicle, the air pressure of the service brake circuit includes the air pressure of the main service brake circuit and the air pressure of the secondary service brake circuit, and the second preset value is specifically 60 PSI.

[0053] When the maximum pressure of the main brake circuit is reduced to the second preset value, the pressure in the PB chamber of the brake cylinder is reduced to balance with the supply pressure of the PB system, so that the PB system can brake according to the pressure of the auxiliary brake circuit, so that the pressure of the auxiliary brake circuit meets the braking requirement. Further, when the maximum pressure of the main brake circuit is reduced to the second preset value, the air pressure in the main brake chamber 192 is reduced, the proportional spring 174 acts on the proportional slider 193 to move the proportional slider 193 upward, the proportional slider 193 drives the main piston 120 to move upward, the main piston 120 releases the supply piston 130, the PB brake chamber 151 and the exhaust passage 131 of the supply piston 130 are communicated, the PB chamber of the brake cylinder is communicated with the exhaust passage 131 through the first port 141 and the PB brake chamber 151, the air in the PB chamber of the brake cylinder can be exhausted through the first port 141, the PB brake chamber 151 and the exhaust passage 131, and the air pressure in the PB chamber of the brake cylinder is reduced. When the air pressure in the PB brake chamber 151 is reduced to the main piston 120 falls to contact the supply piston 130, the control pressure of the PB chamber of the brake cylinder balances with the supply pressure of the PB system, so that the air pressure of the PB system can meet the braking requirement of the brake cylinder, so that the brake can smoothly brake when needed.

[0054] In order to make the proportional slider 193 smoothly drive the main piston 120 to move upward to release the supply piston 130, the part of the piston rod 121 located in the mixed function chamber 190 is provided with a protruding ring part 124 which can be in contact with the proportional slider 193. In this embodiment, the proportional slider 193 is provided with a hole through which the piston rod 121 passes, and the outer diameter of the protruding ring part 124 is greater than the inner diameter of the hole in the proportional slider 193 through which the piston rod 121 passes.

[0055] The other structures of the second embodiment are the same as those of the first embodiment, which will not be described here.

[0056] It can be understood that the second preset value can also be slightly greater than 60 PSI.

[0057] Embodiment three

[0058] In combination Figure 3 , the present embodiment provides a parking brake system, which is used for air braking of a self-powered vehicle, and the parking brake system comprises the type II parking relay valve 100B in the second embodiment.

[0059] In this embodiment, the parking brake system comprises two electromagnetic valves MV1 and MV2, and the two electromagnetic valves MV1 and MV2 are each provided with two ports and two states. Both of the two electromagnetic valves MV1 and MV2 are in a closed state in a normal state, and only when the electromagnetic valves are activated, the two ports of the electromagnetic valves are communicated. Figure 3P1 represents the supply pressure of the PB system, P2 represents the pressure demand of the secondary service brake, P3 represents the pressure of the primary service brake circuit, and P4 represents the pressure of the secondary service brake circuit. The two electromagnetic valves, the type II parking relay valve 100B, and P2 are connected through the high selection valve SH1, and P3 and P4 are connected with the type II parking relay valve 100B through the high selection valve SH2, so as to facilitate the control of the air path flow state of the type II parking relay valve 100B according to the pressure demand.

[0060] When the vehicle is switched from the parking state to the release state, the battery valve MV1 is activated, and the supply pressure switches the high selection valve SH1 to the control side, so as to fill the PB control sub-cavity 152 in the type II parking relay valve 100B. The air pressure in the PB control sub-cavity 152 increases, the main piston 120 drives the supply piston 130 to move downward away from the valve housing 110, and the supply pressure of the PB system can be output to the PB cavity of the brake cylinder through the first port 141, the parking cavity 140, the communication channel 180, the PB brake sub-cavity 151, and the second port 153. When the pressures of the first port 141 and the second port 153 reach the balance, the supply piston 130 is reset under the action of the secondary spring 172, so that the supply piston 130 abuts against the valve housing 110, the communication channel 180 is closed by the supply piston 130, the PB system and the PB cavity of the brake cylinder are disconnected, and the switching from the parking to the release is realized.

[0061] When the vehicle is switched from the release state to the parking state, P2 is 0, the control volumes of the two electromagnetic valves MV1 and MV2 are connected, the electromagnetic valve MV2 is activated, the air in the PB control sub-cavity 152 is released, the air pressure in the PB control sub-cavity 152 decreases, the main piston 120 moves upward under the elastic force of the main spring 171, the main piston 120 releases the supply piston 130, the PB brake sub-cavity 151 and the exhaust channel 131 of the supply piston 130 are communicated, and the air in the PB cavity of the brake cylinder can be exhausted through the first port 141, the PB brake sub-cavity 151, and the exhaust channel 131. The air pressure in the PB cavity of the brake cylinder decreases. When the air pressure in the PB brake sub-cavity 151 decreases to the main piston 120 falling to contact the supply piston 130, the air pressure in the PB cavity of the brake cylinder reaches the minimum, at this time, the brake holds the wheel, and the switching from the release to the parking is realized.

[0062] When the parking brake system and the service brake system act on the brake at the same time, the pressure of the brake PB chamber is too large, which can cause the brake to burst. Based on this, the type II parking relay valve 100B of the embodiment further has a reverse combination function. Specifically, when the reverse combination function needs to be activated, the control quantity between the electromagnetic valve MV1, the electromagnetic valve MV2 and the high selection valve SH1 is the ambient pressure. After the driver steps on the service brake pedal, the pressure switches the high selection valve SH1 to the pressure demand side of the auxiliary service brake circuit, the air pressure in the PB control sub-chamber 152 increases, the main piston 120 drives the supply piston 130 to move downward away from the valve housing 110, and the supply pressure of the PB system can pass through the first port 141, the parking chamber 140, the communication channel 180, the PB brake sub-chamber 151 and the second port 153 to the PB chamber of the brake cylinder. When the pressure of the first port 141 and the second port 153 reaches equilibrium, the supply piston 130 is reset under the action of the auxiliary spring 172, the supply piston 130 is in contact with the valve housing 110, the communication channel 180 is closed by the supply piston 130, and the PB system and the PB chamber of the brake cylinder are disconnected. After the driver releases the brake pedal, the ambient pressure keeps the high selection valve SH1 on the pressure demand side of the auxiliary service brake circuit, the air pressure in the PB control sub-chamber 152 decreases, the main spring 171 pushes the main piston 120 upward, the main piston 120 releases the supply piston 130, and the air in the PB chamber of the brake cylinder is discharged from the exhaust channel 131, similar to switching from the release state to the parking state.

[0063] The other contents of the third embodiment are the same as those in the second embodiment, which will not be repeated here.

[0064] Embodiment Four

[0065] In combination Figure 4 , the embodiment provides a parking brake system for air braking of a vehicle with a trailer, which includes the type I parking relay valve 100A of the first embodiment and the type II parking relay valve 100B of the second embodiment. The type I parking relay valve 100A is arranged on the brake circuit of the trailer, and the type II parking relay valve 100B is arranged on the brake circuit of the vehicle. The brake circuit of the vehicle is the same as that in the third embodiment, which will not be repeated here.

[0066] In this embodiment, two solenoid valves MV3 and MV4 are provided on the brake circuit of the trailer, and the two solenoid valves MV3 and MV4 are each provided with two ports and two states. The two solenoid valves MV3 and MV4 are in a closed state in a normal state, and only when the solenoid valves are activated, the two ports of a single solenoid valve are communicated. P3 and P4 are connected with the type I parking relay valve 100A through the high selection valve SH3, so as to control the gas path flow state of the type I parking relay valve 100A according to the pressure requirement. When the maximum pressure of the main brake circuit and the auxiliary brake circuit is higher than 60 PSI, the trailer brake circuit can be filled. The state switching of the type I parking relay valve 100A in the trailer brake circuit can refer to the description of the switching of the type II parking relay valve 100B to the release state and the parking state in embodiment three, and will not be described here.

[0067] The other contents of embodiment four are the same as those of embodiment three, and will not be described here.

[0068] In addition to the preferred embodiments described above, the present application also has other embodiments, and those skilled in the art can make various changes and modifications according to the present application, as long as they do not deviate from the spirit of the present application, and they should belong to the scope defined in the claims of the present application.

Claims

1. A parking relay valve for use in the air braking of a vehicle, comprising a valve housing, a main piston, and a supply piston, characterized in that, The valve body is provided with a parking chamber, a control chamber and an ejection function chamber arranged in sequence; The main piston includes a piston rod and a piston block disposed at one end of the piston rod. The piston rod passes through the control cavity and the ejection function cavity. The piston block is disposed in the control cavity, and a main spring acting on the piston block is disposed in the control cavity. The parking compartment is provided with a first port for connection to the PB system; The control chamber is divided into a PB braking chamber and a PB control chamber by a piston block. The PB braking chamber has a second port that connects to the PB chamber of the brake cylinder, and the PB control chamber has a third port that connects to the parking control unit. The supply piston passes through the parking chamber and extends into the PB brake chamber. The supply piston is used to control the connection and disconnection between the parking chamber and the PB brake chamber and is provided with a discharge channel that can communicate with the PB brake chamber. The parking chamber is provided with a secondary spring that acts on the supply piston. The pop-out functional cavity is provided with a pop-out slider sleeved on the piston rod and a pop-out spring acting on the pop-out slider. The pop-out slider can drive the main piston to move synchronously. The pop-out functional cavity is divided into an environmental pressure sub-cavity and a pop-out control sub-cavity by the pop-out slider. The environmental pressure sub-cavity is provided with a fourth port communicating with the outside air, and the pop-out control sub-cavity is provided with a fifth port connected to the vehicle braking circuit. When the pressure in the PB control chamber decreases, the main spring drives the piston block to move, connecting the PB chamber of the brake cylinder with the discharge channel of the supply piston, thus achieving braking. When the pressure in the PB control chamber increases, the piston block drives the supply piston to move, connecting the PB system with the PB chamber of the brake cylinder, thus releasing the brake. When the maximum pressure of the service brake circuit drops to the first preset value, the pop-out spring drives the main piston to move and release the supply piston through the pop-out slider, so that the PB chamber of the brake cylinder is connected to the discharge channel of the supply piston, thereby realizing self-braking.

2. The parking relay valve according to claim 1, characterized in that, The piston rod is provided with a protrusion in the pop-out functional cavity that can abut against the pop-out slider.

3. The parking relay valve according to claim 1, characterized in that, The first preset value is 40 PSI.

4. The parking relay valve according to claim 1, characterized in that, The valve housing is provided with a mixing function chamber. The piston rod passes through the mixing function chamber, which is equipped with a proportional slider sleeved on the piston rod and a proportional spring acting on the proportional slider. The proportional slider can drive the main piston to move synchronously. The hybrid functional cavity is divided into a proportional control sub-cavity and a main braking sub-cavity by a proportional slider. The proportional control sub-cavity is provided with a sixth port connected to the auxiliary driving brake circuit, and the main braking sub-cavity is provided with a seventh port connected to the main braking circuit. When the maximum pressure of the main braking circuit drops to the second preset value, the proportional spring drives the main piston to move through the proportional slider and releases the supply piston. The PB chamber of the brake cylinder is depressurized through the discharge channel of the supply piston to balance the pressure with the PB system.

5. The parking relay valve according to claim 4, characterized in that, The second preset value is 60 PSI.

6. The parking relay valve according to claim 4, characterized in that, The piston rod is provided with a convex ring portion in the mixed function chamber that can engage with the proportional slider.

7. A parking brake system for air braking of self-propelled vehicles, characterized in that, The parking brake system includes the parking relay valve as described in any one of claims 4 to 6.

8. A parking brake system for air braking of a vehicle with a trailer, characterized in that, The parking brake system includes the parking relay valve according to any one of claims 1 to 3 and the parking relay valve according to any one of claims 4 to 6. The parking relay valve according to any one of claims 1 to 3 is provided on the trailer's braking circuit. The parking relay valve according to any one of claims 4 to 6 is provided on the vehicle's braking circuit.

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