CN115610399A

CN115610399A - Parking relay valve and parking braking system

Info

Publication number: CN115610399A
Application number: CN202211236481.7A
Authority: CN
Inventors: 陈锋; 安德拉斯·福克斯; 马加什·克拉博特; 胡斐; 陈钢强
Original assignee: Zhejiang VIE Science and Technology Co Ltd
Current assignee: Zhejiang VIE Science and Technology Co Ltd
Priority date: 2022-10-10
Filing date: 2022-10-10
Publication date: 2023-01-17
Also published as: WO2024077699A1

Abstract

The invention discloses a parking relay valve and a parking brake system, belonging to the technical field of vehicle brake equipment, wherein 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 popup 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 popup function cavity in a penetrating way, 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 popup slide block sleeved on the piston rod and a popup spring acting on the popup slide block are arranged in the popup function cavity, the popup slide block can drive the main piston to synchronously move, and the popup function cavity is divided into an environment pressure sub-cavity and a popup control sub-cavity by the popup slide block. The automatic braking is realized when the pressure of the braking circuit is reduced to a certain degree through the popping-up function cavity, so that the vehicle can stop moving in time, and the safety of the vehicle in running is improved.

Description

Parking relay valve and parking braking system

Technical Field

The invention relates to the technical field of vehicle braking equipment, in particular to a parking relay valve.

Background

For safety, the brake of the existing large-scale vehicle has three states of a service state, a service brake state and a parking brake state, a main brake circuit and an auxiliary brake circuit are also generally arranged for realizing the brake, and when the main brake circuit is abnormal or has a fault, the auxiliary brake circuit compensates the main brake so that the vehicle can be smoothly braked. The relay valve is an important component of a vehicle air brake system, and in the air brake system of a large vehicle, the relay valve plays a role in shortening the reaction time and the pressure establishment time. The structure of the conventional relay valve is complex, and when the pressure of a brake circuit is reduced due to the abnormality of a brake system of a vehicle, the structure for realizing self-braking through the relay valve is complex, and the self-braking function cannot be realized through quick response.

Disclosure of Invention

In order to solve the defects and shortcomings in the prior art, the invention provides the parking relay valve, the ejecting function cavity is additionally arranged, when the maximum pressure of a service brake loop is too small, the PB cavity of the brake cylinder is communicated with the discharge channel of the supply piston, the purpose of self-braking is realized, and the running safety of a vehicle is improved.

In order to achieve the above technical objects, the present invention provides a parking relay valve for an air brake of a vehicle, including a valve housing, a main piston, and a supply piston,

the valve shell is provided with a parking cavity, a control cavity and an ejection function cavity which are sequentially distributed;

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 ejection function cavity in a penetrating manner, the piston block is arranged in the control cavity, and 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, 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 part;

the supply piston penetrates 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 a discharge passage which can be communicated with the PB brake sub-cavity, and an auxiliary spring acting on the supply piston is arranged in the parking cavity;

the ejection function cavity is internally provided with an ejection sliding block sleeved on the piston rod and an ejection spring acting on the ejection sliding block, the ejection sliding block can drive the main piston to synchronously move, the ejection function cavity is divided into an environment pressure sub-cavity and an ejection control sub-cavity by the ejection sliding block, the environment pressure sub-cavity is provided with a fourth port communicated with external air, and the ejection control sub-cavity is provided with a fifth port connected with a service braking loop;

when the pressure of the PB control sub-cavity is reduced, the main spring drives the piston block to move, so that the PB cavity of the brake cylinder is communicated with a discharge passage of the supply piston, and braking is realized;

when the pressure of the PB control sub-cavity is increased, the piston block drives the supply piston to move, so that the PB system is communicated with the PB cavity of the brake cylinder to realize release;

when the maximum pressure of the service braking loop is lower than a first preset value, the pop-up spring drives the main piston to move through the pop-up slider to release the supply piston, so that the PB cavity of the brake cylinder is communicated with the discharge channel of the supply piston, and self-braking is realized.

Preferably, the part of the piston rod in the ejection function cavity is provided with a protruding part which can be in interference fit with the ejection slide block.

Preferably, the first preset value is 40PSI.

Preferably, the valve housing is provided with a mixing function chamber,

the piston rod penetrates through the mixing function cavity, a proportional sliding block sleeved on the piston rod and a proportional spring acting on the proportional sliding block are arranged in the mixing function cavity, and the proportional sliding block can drive the main piston to move synchronously;

the mixed function cavity is divided into a proportional control sub-cavity and a main brake sub-cavity by a proportional slider, the proportional control sub-cavity is provided with a sixth port connected with the auxiliary service brake loop, and the main brake sub-cavity is provided with a seventh port connected with the main brake loop;

when the maximum pressure of the main brake circuit is lower than a second preset value, the proportional spring drives the main piston to move through the proportional slider and release the supply piston, and the PB cavity of the brake cylinder is reduced in pressure through the discharge channel of the supply piston to be balanced with the pressure of the PB system.

Preferably, the second preset value is 60PSI.

Preferably, the part of the piston rod in the mixed function cavity is provided with a convex ring part which can be in interference fit with the proportional slide block.

The invention also provides a parking brake system for air braking of a vehicle with power, which comprises the parking relay valve.

The invention also provides a parking brake system for air braking of a vehicle with a trailer, which comprises the two parking relay valves, wherein one parking relay valve is arranged on a brake loop of the trailer, and the other parking relay valve is arranged on the brake loop of the vehicle.

After the technical scheme is adopted, the invention has the following advantages:

1. according to the parking relay valve provided by the invention, the valve shell is provided with the parking cavity, the control cavity and the popping function cavity, the environment pressure sub-cavity of the popping function cavity is communicated with the external air, and the popping control sub-cavity is connected with the service braking loop. When the maximum pressure is reduced to a first preset value due to the fact that a service brake loop breaks down, the pop-up spring acts on the pop-up slider, the pop-up slider drives the main piston to release the supply piston, and therefore the PB cavity of the brake cylinder is communicated with the discharge channel of the supply piston, the pressure of the PB cavity of the brake cylinder is reduced, the brake performs self-braking, and the purpose of automatic parking is achieved. The automatic braking is realized when the pressure of the braking circuit is reduced to a certain degree through the popping-up function cavity, so that the vehicle can stop moving in time, and the safety of the vehicle during running is improved.

2. Furthermore, the valve casing sets up the mixed function chamber, when the main brake return circuit broke down and lead to the maximum pressure to be low to the second default, proportional spring acts on the proportion slider, make and pop out the slider and drive the main piston and remove, the main piston releases the supply piston, the PB chamber and the discharge channel intercommunication of supply piston of brake cylinder, the pressure in PB chamber reduces to the supply pressure balance with the PB system, make braking system can brake according to the pressure condition in vice braking return circuit, thereby make the pressure in vice braking return circuit satisfy the braking requirement.

Drawings

Fig. 1 is a schematic view of an internal structure of a type i parking relay valve according to an embodiment;

FIG. 2 is a schematic view of the internal structure of a type II parking relay valve according to a second embodiment;

FIG. 3 is a schematic view of a parking brake system according to a third embodiment;

fig. 4 is a schematic diagram of a parking brake system according to a fourth embodiment.

In the figure, the parking relay valve of type 100A-i, the parking relay valve of type 100B-ii, 110-valve housing, 120-master piston, 121-piston rod, 122-piston block, 123-projection, 124-collar, 130-supply piston, 131-exhaust 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-eject function chamber, 161-ambient pressure chamber, 162-eject control chamber, 163-eject slider, 164-fourth port, 165-fifth port, 171-master spring, 172-secondary spring, 173-eject spring, 174-proportional spring, 180-communication channel, 190-mixing function chamber, 191-proportional control chamber, 192-master brake chamber, 193-proportional slider, 194-sixth port, 195-seventh port.

Detailed Description

The invention is further described with reference to the following figures and specific examples. It is to be understood that the following terms "upper," "lower," "left," "right," "longitudinal," "lateral," "inner," "outer," "vertical," "horizontal," "top," "bottom," and the like are used merely to indicate an orientation or positional relationship relative to one another as illustrated in the drawings, merely to facilitate describing and simplifying the invention, and are not intended to indicate or imply that the device/component so referred to must have a particular orientation or be constructed and operated in a particular orientation, and therefore are not to be considered limiting of the invention.

Example one

As shown in fig. 1, a parking relay valve 100A of type i according to an embodiment of the present invention, which is used for air braking of a vehicle, includes a valve housing 110, a master piston 120 and a supply piston 130,

the valve housing 110 is provided with a parking chamber 140, a control chamber 150 and an ejection function chamber 160 which are distributed from bottom to top in sequence;

the main piston 120 comprises a piston rod 121 and a piston block 122 arranged at one end of the piston rod 121, the piston rod 121 is arranged in the control cavity 150 and the ejection function cavity 160 in a penetrating manner, the piston block 122 is arranged in the control cavity 150, and a main spring 171 acting on the piston block 122 is arranged in the control cavity 150;

the parking chamber 140 is provided with a first port 141 to which the PB system is connected;

the control chamber 150 is divided into a PB brake chamber 151 and a PB control chamber 152 by the piston block 122, the PB brake chamber 151 is provided with a second port 153 connected with the PB chamber of the brake cylinder, and the PB control chamber 152 is provided with a third port 154 connected with the parking control member;

the supply piston 130 penetrates through the parking cavity 140 and extends into the PB brake subchamber 151, the supply piston 130 is used for controlling the connection and disconnection between the parking cavity 140 and the PB brake subchamber 151 and is provided with a discharge passage 131 which can be communicated with the PB brake subchamber 151, and a secondary spring 172 acting on the supply piston 130 is arranged in the parking cavity 140;

the pop-up function cavity 160 is internally 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 synchronously move, the pop-up function cavity 160 is divided into an environment pressure sub-cavity 161 and a pop-up control sub-cavity 162 by the pop-up slider 163, the environment pressure sub-cavity 161 is provided with a fourth port 164 communicated with external air, and the pop-up control sub-cavity 162 is provided with a fifth port 165 connected with a service braking loop;

when the pressure of the PB control sub-chamber 152 is reduced, the main spring 171 drives the upper piston block 122 to move, so that the PB chamber of the brake cylinder is communicated with the discharge passage 131 of the supply piston 130, and braking is realized;

when the pressure of the PB control sub-chamber 152 is increased, the piston block 122 drives the supply piston 130 to move downwards, so that the PB system is communicated with the PB chamber of the brake cylinder to realize release;

when the maximum pressure of the service braking circuit is lower than a first preset value, the pop-up spring 173 drives the main piston 120 to move upwards through the pop-up slider 163 and releases the supply piston 130, so that the PB chamber of the brake cylinder is communicated with the discharge passage 131 of the supply piston 130, and self-braking is realized.

In order to make the eject slider 163 smoothly drive the main piston 120 to move upward to release the supply piston 130, the piston rod 121 is provided with a protrusion 123 in interference fit with the eject slider 163 at a position in the eject function chamber 160. In this embodiment, the ejecting slider 163 is provided with a hole for the upper end of the piston rod 121 to pass through, the top end of the piston rod 121 is provided with a circle of convex ring forming the protrusion 123, and the outer diameter of the convex ring is larger than the inner diameter of the hole for the piston rod 121 to pass through on the ejecting slider 163.

The i-type parking relay valve 100A of the present embodiment is mainly used for braking a trailer, the air pressure of a service brake loop is consistent with the air pressure of a service brake loop in a tractor, the air pressure of the service brake loop includes the air pressure of a main service brake loop and the air pressure of an auxiliary service brake loop, and the first preset value is specifically 40PSI.

A communication passage 180 is provided between the parking chamber 140 and the PB brake subchamber 151 of the control chamber 150, and a part of the supply piston 130 is located in the communication passage 180. The feed piston 130 may move downward away from the valve housing 110 by the interference of the main piston 120, and at this time, the parking chamber 140 and the PB brake sub-chamber 151 may communicate with each other through the communication passage 180, so that the first port 141 and the second port 153 communicate with each other, and the feed pressure of the PB system may 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 pressures of the first port 141 and the second port 153 reach equilibrium, the feed piston 130 is returned by the force of the sub-spring 172, the feed piston 130 interferes with the valve housing 110, the communication passage 180 is closed by the feed piston 130, the PB system and the PB chamber of the brake cylinder are disconnected, and the switch from parking to release is achieved.

When parking is needed, air in the PB control sub-chamber 152 is exhausted, air pressure in the PB control sub-chamber 152 is reduced, the main piston 120 moves upwards under the action of 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 exhaust passage 131 of the supply piston 130 to be communicated, the PB chamber of the brake cylinder is communicated with the exhaust passage 131 through the first port 141 and the PB brake sub-chamber 151, air in the PB chamber of the brake cylinder can be exhausted through the first port 141, the PB brake sub-chamber 151 and the exhaust passage 131, and air pressure in the PB chamber of the brake cylinder is reduced. When the air pressure in the PB chamber 151 decreases until the master piston 120 falls back into contact with the supply piston 130, the air pressure in the PB chamber of the brake cylinder reaches a minimum, at which time the brake grips the wheel and a switch from released to parked is made.

When the air pressure of the service brake circuit is lower than a first preset value, which indicates that the service brake circuit has a fault, at this time, the air pressure in the pop-up control sub-chamber 162 is reduced, the pop-up spring 173 acts on the pop-up slider 163, so that the pop-up slider 163 drives the main piston 120 to move upwards to release the supply piston 130, the PB sub-chamber 151 is communicated with the discharge passage 131 of the supply piston 130, the PB chamber of the brake cylinder can be communicated with the discharge passage 131 through the first port 141 and the PB sub-chamber 151, the air in the PB chamber of the brake cylinder can be discharged through the first port 141, the PB sub-chamber 151 and the discharge passage 131, and the air pressure in the PB chamber of the brake cylinder is reduced. When the air pressure in the PB brake subchamber 151 is reduced to the point that the main piston 120 falls back to contact with 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 tightly, and the brake performs self-braking, thereby achieving the purpose of automatic parking. The self-braking is realized when the pressure of the braking circuit is reduced to a certain degree through the popping-up function cavity 160, so that the vehicle can stop moving in time, and the safety of the vehicle in running is improved.

It is understood that the first preset value may also be slightly greater than 40PSI.

Example two

Referring to fig. 2, the present embodiment discloses a type ii parking relay valve 100B, and the type ii parking relay valve 100B of the present embodiment is additionally provided with a mixed function chamber 190 on the basis of the structure of the first embodiment, and the mixed function chamber 190 is located between the control chamber 150 and the pop-up function chamber 160. In this embodiment, the piston rod 121 of the main piston 120 passes through the mixing function chamber 190, the mixing function chamber 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 chamber 190 is divided into a proportional control subchamber 191 and a main brake subchamber 192 by a proportional slider 193, the proportional control subchamber 191 is provided with a sixth port 194 connected with the auxiliary service brake circuit, and the main brake subchamber 192 is provided with a seventh port 195 connected with the main brake circuit. When the maximum pressure of the main brake circuit is lower than the second preset value, the proportional spring 174 drives the main piston 120 to move upwards through the proportional slider 193 and releases the supply piston 130, and the PB chamber of the brake cylinder is depressurized to be balanced with the supply pressure of the PB system through the discharge passage 131 of the supply piston 130.

The type ii parking relay valve 100B of this 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 auxiliary service brake circuit, and the second preset value is 60PSI specifically.

When the main brake circuit breaks down to cause the maximum pressure to be lower than a second preset value, the pressure of the PB cavity of the brake cylinder is reduced to be balanced with the supply pressure of the PB system, so that the PB 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. Further, when the maximum pressure of the main brake circuit is lower than the second preset value, the air pressure in the main brake sub-chamber 192 is reduced, the proportional spring 174 acts on the proportional slider 193 to move the proportional slider 193 upwards, the proportional slider 193 drives the main piston 120 to move upwards, 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 to communicate, the PB chamber of the brake cylinder communicates with the discharge passage 131 through the first port 141 and the PB brake sub-chamber 151, 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, and the air pressure in the PB chamber of the brake cylinder is reduced. When the air pressure in the PB brake subchamber 151 is reduced to the point that the main piston 120 falls back to contact with the supply piston 130, the control pressure of the PB chamber and the supply pressure of the PB system reach balance, so that the air pressure of the PB system can meet the braking requirement of the brake cylinder, and the brake can be smoothly braked when braking is required.

In order to make the proportional slider 193 smoothly move the main piston 120 upward to release the supply piston 130, the piston rod 121 is provided with a convex ring portion 124 in interference fit with the proportional slider 193 at a position in the mixing function chamber 190. 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 convex ring portion 124 is larger than the inner diameter of the hole through which the piston rod 121 passes on the proportional slider 193.

The other structures of the second embodiment are the same as those of the first embodiment, and are not described herein again.

It is understood that the second preset value may also be slightly greater than 60PSI.

EXAMPLE III

In conjunction with fig. 3, the present embodiment provides a parking brake system for air braking of an autonomous vehicle, the parking brake system including a type ii parking relay valve 100B of the second embodiment.

In this embodiment, the parking brake system includes two solenoid valves MV1, MV2, and two solenoid valves MV1, MV2 all are equipped with two ports and two kinds of states, and two battery valves MV1, MV2 all are in the closed condition under the normality, and only when the solenoid valve was activated, two ports of solenoid valve just communicate. In fig. 3, P1 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 solenoid valves, the II-type parking relay valve 100B and the P2 are connected through the high selection valve SH1, and the P3 and the P4 are connected with the II-type parking relay valve 100B through the high selection valve SH2, so that the air path circulation state of the II-type parking relay valve 100B can be conveniently controlled according to pressure requirements.

When the vehicle is switched from the parking state to the release state, the battery valve MV1 is activated, the supply pressure switches the high selector valve SH1 to the control side, so that the PB control sub-chamber 152 in the type ii parking relay valve 100B is filled, the air pressure in the PB control sub-chamber 152 is increased, 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 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 pressures of the first and

second ports

141 and 153 reach equilibrium, the feed piston 130 is returned by the force of the secondary spring 172, the feed piston 130 is caused to abut against the valve housing 110, the communication passage 180 is closed by the feed piston 130, the PB chamber of the PB system and the PB chamber of the brake cylinder are disconnected, and the switch from parking to release is achieved.

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, air in the PB control sub-chamber 152 is released, air pressure in the PB control sub-chamber 152 is reduced, the master piston 120 moves upwards under the elastic force of the master spring 171, the master piston 120 releases the supply piston 130, the PB brake sub-chamber 151 is communicated with the discharge passage 131 of the supply piston 130, 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, and air pressure in the PB chamber of the brake cylinder is reduced. When the air pressure in the PB brake subchamber 151 decreases until the master piston 120 falls back into contact with the supply piston 130, the air pressure in the PB chamber of the brake cylinder reaches a minimum, at which time the brake grips the wheel and a switch from released to parked is made.

Since the parking brake system and the service brake system realize parking and releasing through the same brake, when the parking brake system and the service brake system act on the brake at the same time, the pressure of the PB cavity is too high, which can cause the brake to explode. In this regard, the type ii parking relay valve 100B of the present embodiment also has a repeat-and-turn function. Specifically, when the repeated closing function needs to be activated, the control quantity among 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 is increased, so that the main piston 120 drives the supply piston 130 to move downward to leave the valve housing 110, and the supply pressure of the PB system can be used for gripping the PB chamber of the brake cylinder through the first port 141, the parking chamber 140, the communication channel 180, the PB brake sub-chamber 151 and the second port 153. When the pressures of the first and

second ports

141 and 153 reach an equilibrium, the feed piston 130 is returned by the force of the secondary spring 172, the feed piston 130 interferes with the valve housing 110, the communication passage 180 is closed by the feed piston 130, and the PB system and the PB chamber of the brake cylinder are disconnected. When the driver releases the brake pedal, the ambient pressure holds the high selector valve SH1 on the side of the auxiliary service brake circuit pressure demand, the PB control branch chamber 152 drops the air pressure, the master spring 171 pushes the master piston 120 upward, the master piston 120 releases the supply piston 130, and the air in the brake cylinder PB chamber is discharged from the discharge passage 131, similarly switching from the released state to the parking state.

The other contents of the third embodiment are the same as those of the second embodiment, and are not described herein.

Example four

With reference to fig. 4, the present embodiment provides a parking brake system for air braking of a vehicle with a trailer, including a first type i parking relay valve 100A according to a first embodiment and a second type ii parking relay valve 100B according to a second embodiment, where the first type i parking relay valve 100A is disposed on a brake circuit of the trailer, and the second type ii parking relay valve 100B is disposed on a brake circuit of the vehicle, and the brake circuit of the vehicle is the same as that in the third embodiment, and will not be described again.

In this embodiment, be equipped with two solenoid valves MV3, MV4 on the braking circuit of trailer, two solenoid valves MV3, MV4 all are equipped with two ports and two kinds of states, and two battery valves MV3, MV4 are in closed condition under the normality, only when the solenoid valve is activated, two ports of single solenoid valve just communicate, and P3 and P4 are connected with i type parking relay valve 100A through high-pressure selector valve SH3, are convenient for control i type parking relay valve 100A's gas circuit circulation state according to the pressure demand. The trailer brake circuit may be filled when the maximum pressure of the primary and secondary brake circuits is above 60PSI. For the switching of the state of the type i parking relay valve 100A in the trailer brake circuit, reference may be made to the description of the third embodiment regarding the switching of the type ii parking relay valve 100B to the release state and the switching to the parking state, and details thereof are not repeated here.

The other contents of the fourth embodiment are the same as those of the third embodiment, and are not repeated here.

Other embodiments of the present invention than the preferred embodiments described above, and those skilled in the art can make various changes and modifications according to the present invention without departing from the spirit of the present invention, should fall within the scope of the present invention defined in the claims.

Claims

1. The parking relay valve is used for air braking of a vehicle and comprises a valve shell, a main piston and a supply piston, and is characterized in that the valve shell is provided with a parking cavity, a control cavity and an ejection function cavity which are sequentially distributed;

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-up function cavity in a penetrating manner, the piston block is arranged in the control cavity, and 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 supply piston penetrates 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 a discharge channel which can be communicated with the PB brake sub-cavity, and an auxiliary spring acting on the supply piston is arranged in the parking cavity;

when the pressure of the PB control sub-cavity is increased, the piston block drives the supply piston to move, so that the PB system is communicated with the PB cavity of the brake cylinder, and release is realized;

2. The parking relay valve as recited in claim 1 wherein the portion of the piston rod located in the ejection function chamber is provided with a projection that is interference fit with the ejection slider.

3. The park relay valve according to claim 1, wherein the first predetermined value is 40PSI.

4. The park relay valve of claim 1,

the valve housing is provided with a mixing function chamber,

when the maximum pressure of the main brake circuit is lower than a second preset value, the proportional spring drives the main piston to move through the proportional slider and releases the supply piston, and the PB cavity of the brake cylinder is depressurized to be balanced with the pressure of the PB system through the discharge channel of the supply piston.

5. The park relay valve according to claim 4, wherein the second predetermined value is 60PSI.

6. The park relay valve according to claim 4, wherein a portion of said piston rod located in the hybrid function chamber is provided with a collar portion adapted to interference fit with the proportional slide.

7. Parking brake system for air braking of a self-powered vehicle, characterized in that it comprises a parking relay valve according to any of claims 4 to 6.

8. Parking brake system for air braking of a vehicle with trailer, characterized in that,

the parking brake system includes the parking relay valve of any one of claims 1 to 3 and the parking relay valve of any one of claims 4 to 6,

a parking relay valve as claimed in any one of claims 1 to 3, provided on the brake circuit of a trailer,

a parking relay valve as defined in any of claims 4 to 6 provided in a brake circuit of a vehicle.