A pressure control device and method for railway freight car brake cylinders

Abstract

This invention belongs to the technical field of air braking systems for railway vehicles, and specifically relates to a pressure control device and method for a railway freight car brake cylinder. The device includes a valve body, within which a first valve stem is disposed, and second valve stems are disposed vertically within the valve stems. A valve seat is fixed within the lower section of the valve body. A sandwich valve is also fitted inside the valve body. The cavity on the upper side of the valve stem communicates with the train pipe. An annular cavity is disposed between the valve stem and the valve body, and this annular cavity communicates with the brake cylinder. An air intake cavity is connected to the lower side of the annular cavity, and this air intake cavity communicates with the auxiliary air cylinder. The cavity on the lower side of the valve seat communicates with the emergency air cylinder. A first small hole is provided on the first valve stem. The cross-sectional area of ​​the first small hole on the first valve stem is smaller than the cross-sectional area of ​​the annular cavity, achieving a rapid increase in the emergency braking force of the train, which then decreases, thereby reducing the longitudinal impulse of the train. Because the emergency air cylinder communicates with the auxiliary air cylinder during emergency braking, the brake cylinder can obtain greater pressure than during normal braking, thus shortening the stopping distance.

Description

Technical Field

[0001] This invention belongs to the technical field of air braking systems for railway vehicles, and specifically relates to a pressure control device and method for brake cylinders of railway freight cars. Background Technology

[0002] When used in railway vehicle air braking systems, especially for trains exceeding 700 meters in length and consisting of 50 or more cars, the stress state of the vehicles during emergency braking is extremely complex, posing a significant risk of derailment. Therefore, it is necessary to rationally control the rate of increase in braking force to reduce the longitudinal impact force during emergency braking, ensuring the train stops safely within a specified distance. Summary of the Invention

[0003] In order to solve the above-mentioned problems in the prior art, the purpose of this invention is to provide a railway freight car brake cylinder pressure control device and method that can reduce the longitudinal impulse of the train and have greater braking force.

[0004] The technical solution adopted in this invention is as follows:

[0005] A pressure control device for a railway freight car brake cylinder includes a valve body, a first valve stem disposed within the valve body, a first spring connecting the upper side of the first valve stem to the valve body, a second spring and a second valve stem disposed vertically within the valve stem, a valve seat fixed within the lower section of the valve body, and a sandwich valve sleeved within the valve body, the sandwich valve located between the second valve stem and the valve seat, with a third spring disposed between the valve seat and the sandwich valve; the cavity on the upper side of the valve stem communicates with a train pipe, an annular cavity is provided between the valve stem and the valve body, and the annular cavity communicates with the brake cylinder. A limit ring is provided at the lower end of a valve stem. The lower side of the annular cavity is connected to an air intake cavity. A limiting step is provided between the annular cavity and the air intake cavity to cooperate with the limit ring. The air intake cavity is connected to the auxiliary air cylinder. The cavity on the lower side of the valve seat is connected to the emergency air cylinder. The valve seat is a hollow structure. A gap is left between the sandwich valve and the valve body. A first small hole is provided on the first valve stem to connect the inner cavity of the first valve stem and the annular cavity. A second small hole is provided on the second valve stem. The cross-sectional area of ​​the first small hole is smaller than the cross-sectional area of ​​the annular cavity.

[0006] The cross-sectional area of ​​the first small hole on the first valve stem is smaller than that of the annular cavity. Therefore, the pressure rise rate of the brake cylinder is lower than when the first valve stem is not activated, resulting in a rapid increase in emergency braking force followed by a decrease in speed, thus reducing longitudinal impact on the train. Because the emergency air cylinder communicates with the auxiliary air cylinder during emergency braking, the brake cylinder can obtain greater pressure than during normal braking, thereby shortening the stopping distance. This invention achieves integrated control of the two-stage speed increase of emergency braking force and brake pressurization function, achieving the effects of reducing the longitudinal force during emergency braking and shortening the emergency braking distance.

[0007] As a preferred embodiment of the present invention, the valve body is provided with a support step for supporting the limiting ring. During normal braking, or during emergency braking when the force of the brake cylinder acting on the first valve stem is less than the compression force of the first spring, the lower end of the first valve stem remains in contact with the support step of the valve body. The second spring inside the first valve stem presses the sandwich valve onto the valve seat through the second valve stem. The emergency air cylinder remains isolated from the auxiliary air cylinder, and the gas from the auxiliary air cylinder enters the brake cylinder after passing through the intake chamber and the annular chamber.

[0008] In a preferred embodiment of the present invention, a first retaining ring is provided in the valve body for limiting the position of the sandwich valve, with a gap between one side of the sandwich valve and the first retaining ring. The first retaining ring limits the position of the sandwich valve, ensuring that the sandwich valve is always on the upper side of the valve seat, facilitating the pressing of the sandwich valve onto the valve seat by the second valve rod. The gap between one side of the sandwich valve and the first retaining ring allows the first valve rod to detach from the valve body during emergency braking when the force acting on the first valve rod exceeds the compressive force of the first spring. The first valve rod then drives the second valve rod to detach from the sandwich valve. Under the combined action of the third spring and the air pressure from the emergency air cylinder, the sandwich valve detaches from the valve seat. Gas from the emergency air cylinder can enter the intake chamber through the cavity below the valve seat, the hollow cavity of the valve seat, and the gap between one side of the sandwich valve and the first retaining ring, thus enabling communication between the emergency air cylinder and the auxiliary air cylinder.

[0009] In a preferred embodiment of the present invention, a second retaining ring is provided inside the first valve stem to limit the movement of the second valve stem. The second retaining ring limits the movement of the second valve stem, preventing the second valve stem from dislodging from the inner cavity of the first valve stem.

[0010] In a preferred embodiment of the present invention, a first O-ring seal is provided on the first valve stem near the limiting ring. During emergency braking, when the force acting on the first valve stem is greater than the compressive force of the first spring, the lower end of the first valve stem disengages from the supporting step until the limiting ring contacts the limiting step. At this time, the first O-ring seal contacts the valve body, isolating the intake chamber and the annular cavity, ensuring that the gas from the emergency air cylinder and the auxiliary air cylinder enters the brake cylinder through the intake chamber, the second small hole, the inner cavity of the first valve stem, the first small hole, and the annular cavity.

[0011] As a preferred embodiment of the present invention, a second O-ring is provided between the first valve stem and the valve body.

[0012] In a preferred embodiment of the present invention, a boss is provided at the upper end of the valve stem, and a first spring is sleeved on the boss. The boss positions the first spring to ensure its stability.

[0013] In a preferred embodiment of the present invention, a mounting ring groove is provided on the outside of the valve seat, and the third spring is sleeved on the mounting ring groove. The mounting ring groove positions the third spring and ensures the stability of the third spring.

[0014] As a preferred embodiment of the present invention, the second valve stem includes a valve ring, which is sleeved inside the first valve stem, a second small hole is provided on the valve ring, and a rod body is provided at the lower end of the valve ring.

[0015] A method for controlling the pressure of a railway freight car brake cylinder includes the following steps:

[0016] During normal braking, the train pipe maintains a certain pressure. Under the combined action of the train pipe pressure and the first spring, the lower end of the first valve stem contacts the valve body. The auxiliary air cylinder and the brake cylinder communicate through the air intake chamber and the annular chamber.

[0017] During emergency braking, the air in the train pipe is purged, and the chamber at the top of the first valve stem, which is connected to the train pipe, is empty of pressurized air. When the force exerted by the brake cylinder on the first valve stem is less than the compressive force of the first spring, the lower end of the first valve stem remains in contact with the valve body. The second spring inside the first valve stem presses the sandwich valve onto the valve seat through the second valve stem, and the emergency air cylinder remains isolated from the auxiliary air cylinder. When the brake cylinder pressure continues to rise, and the force exerted on the first valve stem exceeds the compressive force of the first spring, the lower end of the first valve stem disengages from the valve body until the limiting ring contacts the limiting step. The first valve stem then drives the second valve stem to disengage from the sandwich valve. Under the combined action of the third spring and the air pressure from the emergency air cylinder, the sandwich valve disengages from the valve seat. The emergency air cylinder then communicates with the auxiliary air cylinder, and the pressurized air from both the emergency air cylinder and the auxiliary air cylinder continues to fill the brake cylinder through the second small hole of the second valve stem and the first small hole of the first valve stem.

[0018] The beneficial effects of this invention are as follows:

[0019] In this invention, the cross-sectional area of ​​the first small hole on the first valve stem is smaller than that of the annular cavity. The pressure rise rate of the brake cylinder is lower than when the first valve stem is not activated, achieving a rapid increase in emergency braking force followed by a decrease in speed, thereby reducing the longitudinal impact on the train. Because the emergency air cylinder communicates with the auxiliary air cylinder during emergency braking, the brake cylinder can obtain greater pressure than during normal braking, thus shortening the stopping distance. This invention achieves integrated control of the two-stage speed increase of emergency braking force and the brake pressurization function, achieving the effects of reducing the longitudinal force during emergency braking and shortening the emergency braking distance. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the operation of the present invention during emergency braking.

[0021] Figure 2 A schematic diagram of the structure of this invention during emergency braking;

[0022] Figure 3 This is a schematic diagram of the operation of the present invention during braking.

[0023] Figure 4 This is a schematic diagram of the structure during the commonly used braking process of this invention.

[0024] In the diagram: 1-First spring; 2-Valve body; 3-First valve stem; 4-Second spring; 5-Second valve stem; 6-Sandwich valve; 7-Valve seat; 8-Third spring; 9-First retaining ring; 10-Second retaining ring; 11-First O-ring seal; 12-Control valve; 13-Auxiliary air cylinder; 14-Emergency air cylinder; 15-Train pipe; 16-Brake cylinder; 17-Wheel; 18-Annular cavity; 19-Intake cavity; 20-Limiting ring; 21-Limiting step; 22-Supporting step; 23-Second O-ring seal; 24-First small hole; 25-Second small hole. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0026] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention. It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of the invention can be combined with each other.

[0027] like Figures 1-4 As shown, the train pipe 15, auxiliary air cylinder 13, and emergency air cylinder 14 are all connected to the railway freight car brake cylinder pressure control device of the present invention through the passage of control valve 12. The brake cylinder 16 is connected to the brake shoes for braking the wheels 17. When the train brakes, the pressurized air in the train pipe 15 is discharged to the atmosphere. Control valve 12 connects the passages between the auxiliary air cylinder 13 and the brake cylinder 16, and between the emergency air cylinder 14 and the brake cylinder 16. The pressurized air in the auxiliary air cylinder 13, or the combined pressurized air in the auxiliary air cylinder 13 and the emergency air cylinder 14, acts on the wheels 17 through the brake cylinder 16 to form the vehicle braking force. The magnitude of the braking force changes with the pressure of the brake cylinder 16.

[0028] The railway freight car brake cylinder pressure control device of this embodiment includes a valve body 2, a first valve stem 3 is disposed inside the valve body 2, a first spring 1 is connected between the upper side of the first valve stem 3 and the valve body 2, a second spring 4 and a second valve stem 5 are disposed vertically inside the valve stem, a valve seat 7 is fixed in the lower section of the valve body 2, and a sandwich valve 6 is also sleeved inside the valve body 2, the sandwich valve 6 is located between the second valve stem 5 and the valve seat 7, and a third spring 8 is disposed between the valve seat 7 and the sandwich valve 6; the cavity on the upper side of the valve stem is connected to the train pipe 15, an annular cavity 18 is disposed between the valve stem and the valve body 2, and the annular cavity 18 is connected to the brake cylinder 16, the first valve stem 3... A limiting ring 20 is provided at the lower end of the valve seat 18. An air intake chamber 19 is connected to the lower side of the annular cavity 18. A limiting step 21 for cooperating with the limiting ring 20 is provided between the annular cavity 18 and the air intake chamber 19. The air intake chamber 19 is connected to the auxiliary air cylinder 13. The cavity on the lower side of the valve seat 7 is connected to the emergency air cylinder 14. The valve seat 7 is a hollow structure. A gap is left between the sandwich valve 6 and the valve body 2. A first small hole 24 is provided on the first valve stem 3 to connect the inner cavity of the first valve stem 3 and the annular cavity 18. A second small hole 25 is provided on the second valve stem 5. The cross-sectional area of ​​the first small hole 24 is smaller than the cross-sectional area of ​​the annular cavity 18.

[0029] The cross-sectional area of ​​the first small hole 24 on the first valve stem 3 is smaller than that of the annular cavity 18. Therefore, the pressure rise rate of the brake cylinder 16 is lower than when the first valve stem 3 is not activated, resulting in a rapid increase in the emergency braking force followed by a decrease in speed, thus reducing the longitudinal impulse of the train. Because the emergency air cylinder 14 communicates with the auxiliary air cylinder 13 during emergency braking, the brake cylinder 16 can obtain a greater pressure than during normal braking, thereby shortening the stopping distance. This invention achieves integrated control of the two-stage speed increase of the emergency braking force and the brake pressurization function, thereby reducing the longitudinal force during emergency braking and shortening the emergency braking distance.

[0030] Furthermore, the valve body 2 is provided with a support step 22 for supporting the limiting ring 20. During normal braking, or during emergency braking when the force of the brake cylinder 16 acting on the first valve stem 3 is less than the compression force of the first spring 1, the lower end of the first valve stem 3 remains in contact with the support step 22 of the valve body 2. The second spring 4 inside the first valve stem 3 presses the sandwich valve onto the valve seat 7 through the second valve stem 5. The emergency air cylinder 14 remains isolated from the auxiliary air cylinder 13, and the gas from the auxiliary air cylinder 13 enters the brake cylinder 16 after passing through the air intake chamber 19 and the annular chamber 18.

[0031] The valve body 2 is provided with a first retaining ring 9 for limiting the position of the sandwich valve 6, with a gap between one side of the sandwich valve 6 and the first retaining ring 9. The first retaining ring 9 limits the position of the sandwich valve 6, ensuring that the sandwich valve 6 is always on the upper side of the valve seat 7, facilitating the pressing of the sandwich valve 6 onto the valve seat 7 by the second valve rod 5. The gap between one side of the sandwich valve 6 and the first retaining ring 9 allows the first valve rod 3 to detach from the valve body 2 during emergency braking when the force acting on the first valve rod 3 exceeds the compressive force of the first spring 1. The first valve rod 3 then drives the second valve rod 5 to detach from the sandwich valve. Under the combined action of the third spring 8 and the air pressure of the emergency air cylinder 14, the sandwich valve 6 detaches from the valve seat 7. The gas from the emergency air cylinder 14 can enter the intake chamber 19 through the lower cavity of the valve seat 7, the hollow cavity of the valve seat 7, and the gap between one side of the sandwich valve 6 and the first retaining ring 9, thus enabling communication between the emergency air cylinder 14 and the auxiliary air cylinder 13.

[0032] The first valve stem 3 is provided with a second retaining ring 10 for limiting the second valve stem 5. The second retaining ring 10 limits the second valve stem 5 to prevent the second valve stem 5 from coming out of the inner cavity of the first valve stem 3.

[0033] To ensure a tight seal, a first O-ring seal 11 is provided on the first valve stem 3 near the limiting ring 20. During emergency braking, when the force acting on the first valve stem 3 exceeds the compressive force of the first spring 1, the lower end of the first valve stem 3 disengages from the supporting step 22 until the limiting ring 20 contacts the limiting step 21. At this time, the first O-ring seal 11 contacts the valve body 2, isolating the intake chamber 19 and the annular cavity 18, ensuring that the gas from the emergency air cylinder 14 and the auxiliary air cylinder 13 enters the brake cylinder 16 through the intake chamber 19, the second small hole 25, the inner cavity of the first valve stem 3, the first small hole 24, and the annular cavity 18.

[0034] A second O-ring 23 is provided between the first valve stem 3 and the valve body 2.

[0035] For ease of installation, a boss is provided at the upper end of the valve stem, and the first spring 1 is sleeved on the boss. The boss positions the first spring 1, ensuring its stability.

[0036] The valve seat 7 is provided with an mounting ring groove, and the third spring 8 is sleeved on the mounting ring groove. The mounting ring groove positions the third spring 8 to ensure its stability.

[0037] The second valve stem 5 includes a valve ring, which is sleeved inside the first valve stem 3. A second small hole 25 is provided on the valve ring, and a rod body is provided at the lower end of the valve ring.

[0038] The method for controlling the brake cylinder pressure of railway freight cars in this embodiment includes the following steps:

[0039] like Figure 3 and Figure 4As shown, during normal braking, the train pipe 15 maintains a certain pressure. Under the combined action of the pressure in the train pipe 15 and the first spring 1, the limiting ring 20 of the first valve stem 3 contacts the supporting step 22. The auxiliary air cylinder 13 and the brake cylinder 16 communicate through the air intake chamber 19 and the annular chamber 18. The second spring 4 inside the first valve stem 3 presses the sandwich valve onto the valve seat 7 through the second valve stem 5, and the emergency air cylinder 14 remains isolated from the auxiliary air cylinder 13. The gas from the auxiliary air cylinder 13 enters the brake cylinder 16 through the air intake chamber 19 and the annular chamber 18, thus achieving braking.

[0040] like Figure 1 and Figure 2 As shown, during emergency braking, the air in the train pipe 15 is vented, and there is no pressurized air in the chamber above the first valve stem 3 that communicates with the train pipe 15.

[0041] Emergency braking stage 1: When the force exerted by the brake cylinder 16 on the first valve stem 3 is less than the compressive force of the first spring 1, the lower end of the first valve stem 3 remains in contact with the valve body 2. The second spring 4 inside the first valve stem 3 presses the sandwich valve onto the valve seat 7 through the second valve stem 5, and the emergency air cylinder 14 remains isolated from the auxiliary air cylinder 13. During the emergency braking stage 1, the gas from the auxiliary air cylinder 13 enters the brake cylinder 16 through the intake chamber 19 and the annular chamber 18. In this stage, the braking force increases rapidly, which can shorten the total braking time.

[0042] Emergency braking second stage: As the pressure in brake cylinder 16 continues to rise, when the force acting on the first valve stem 3 exceeds the compression force of the first spring 1, the limiting ring 20 of the first valve stem 3 disengages from the supporting step 22 until the limiting ring 20 contacts the limiting step 21. The first valve stem 3 then drives the second valve stem 5 to disengage from the sandwich valve. Under the combined action of the third spring 8 and the air pressure from the emergency air cylinder 14, the sandwich valve 6 disengages from the valve seat 7. In this stage, the gas from the emergency air cylinder 14 enters the intake chamber 19 through the cavity below the valve seat 7, the hollow cavity of the valve seat 7, and the gap between the sandwich valve 6 and the first retaining ring 9, merging with the gas sent into the intake chamber 19 by the auxiliary air cylinder 13. The emergency air cylinder 14 communicates with the auxiliary air cylinder 13. The pressurized air from the emergency air cylinder 14 and the auxiliary air cylinder 13 continues to inflate the brake cylinder 16 through the second small hole 25 of the second valve stem 5, the inner cavity of the first valve stem 3, and the first small hole 24 of the first valve stem 3.

[0043] This invention enables a two-stage increase in emergency braking force. The first stage of emergency braking involves a rapid increase in braking force, resulting in rapid train deceleration. The second stage involves a slower increase in braking force, reducing longitudinal impulse. During the second stage of emergency braking, the emergency air cylinder 14 communicates with the auxiliary air cylinder 13, allowing the brake cylinder 16 to obtain greater pressure than during normal braking, thereby shortening the stopping distance. The device of this invention has a compact structure, and the two functions of increasing emergency braking force in two stages are achieved through the movement of the valve stem.

[0044] This invention is not limited to the above-described optional embodiments. Anyone can derive other various forms of products under the guidance of this invention. However, regardless of any changes made in their shape or structure, any technical solution that falls within the scope of the claims of this invention shall be protected by this invention.

Claims

1. A railway car brake cylinder pressure control apparatus characterized by: The utility model provides a kind of valve, including valve body (2), first valve rod (3) is provided in valve body (2), first spring (1) is connected between the upper side of first valve rod (3) and valve body (2), second spring (4) and second valve rod (5) are provided in valve rod upper and lower, the lower section of valve body (2) is fixed with valve seat (7), valve body (2) is also set with sandwich valve (6), sandwich valve (6) is located between second valve rod (5) and valve seat (7), third spring (8) is provided between valve seat (7) and sandwich valve (6);The cavity of the upper side of the valve rod is communicated with train pipe (15), annular cavity (18) is provided between valve rod and valve body (2), annular cavity (18) is communicated with brake cylinder (16), the lower end of first valve rod (3) is provided with limit ring (20), the lower side of annular cavity (18) is communicated with air inlet cavity (19), limit step (21) for cooperating with limit ring (20) is provided between annular cavity (18) and air inlet cavity (19), air inlet cavity (19) is communicated with auxiliary air cylinder (13);The cavity of the lower side of valve seat (7) is communicated with emergency air cylinder (14), valve seat (7) is hollow structure, gap is left between sandwich valve (6) and valve body (2), first valve rod (3) is provided with first pinhole (24) for communicating the cavity in first valve rod (3) with annular cavity (18), second valve rod (5) is provided with second pinhole (25), the cross-sectional area of first pinhole (24) is less than the cross-sectional area of annular cavity (18).

2. A railway car brake cylinder pressure control device as defined in claim 1 wherein: The valve body (2) is provided with a supporting step (22) for supporting the limit ring (20).

3. A railway car brake cylinder pressure control device as defined in claim 1 wherein: The valve body (2) is provided with a first retainer ring (9) for limiting the sandwich valve (6), and a gap is left between one side of the sandwich valve (6) and the first retainer ring (9).

4. A railway car brake cylinder pressure control device as defined in claim 1 wherein: The first valve rod (3) is provided with a second retainer ring (10) for limiting the second valve rod (5).

5. A railway car brake cylinder pressure control device as defined in claim 1 wherein: The first valve rod (3) is provided with a first O-shaped sealing ring (11) near the limit ring (20).

6. A railway car brake cylinder pressure control device as defined in claim 1 wherein: The first valve rod (3) and the valve body (2) are provided with a second O-shaped sealing ring (23).

7. A railway car brake cylinder pressure control device as defined in claim 1 wherein: The upper end of the valve rod is provided with a boss, and the first spring (1) is sleeved on the boss.

8. A railway car brake cylinder pressure control device as defined in claim 1 wherein: The valve seat (7) is provided with a mounting ring groove, and the third spring (8) is sleeved on the mounting ring groove.

9. A railway car brake cylinder pressure control device as defined in claim 1 wherein: The second valve rod (5) includes a valve ring, the valve ring is sleeved in the first valve rod (3), the second pinhole (25) is arranged on the valve ring, and the lower end of the valve ring is provided with a rod body.

10. A method of controlling the pressure of a railway wagon brake cylinder, using the railway wagon brake cylinder pressure control device according to any one of claims 1 to 9, characterized by: The utility model provides a kind of valve, including the following steps: When normal braking, the train pipe (15) maintains a certain pressure, under the joint action of the train pipe (15) pressure and the first spring (1), the lower end of the first valve rod (3) is in contact with the valve body (2), and the auxiliary air cylinder (13) and the brake cylinder (16) are communicated through the air inlet cavity (19) and the annular cavity (18); When emergency braking, the train pipe (15) air is exhausted, the chamber of the first valve rod (3) upper part communicated with the train pipe (15) has no pressure air, when the force of the brake cylinder (16) acting on the first valve rod (3) is less than the compression force of the first spring (1), the lower end of the first valve rod (3) keeps in contact with the valve body (2), the second spring (4) inside the first valve rod (3) keeps the sandwich valve pressed on the valve seat (7) through the second valve rod (5), the emergency air cylinder (14) keeps isolated from the auxiliary air cylinder (13); when the pressure of the brake cylinder (16) continues to rise, the force acting on the first valve rod (3) is greater than the compression force of the first spring (1), the lower end of the first valve rod (3) is separated from the valve body (2) until the limiting ring (20) contacts the limiting step (21), the first valve rod (3) drives the second valve rod (5) to separate from the sandwich valve, the sandwich valve (6) is separated from the valve seat (7) under the joint action of the third spring (8) and the air pressure of the emergency air cylinder (14), the emergency air cylinder (14) communicates with the auxiliary air cylinder (13), the pressure air of the emergency air cylinder (14) and the auxiliary air cylinder (13) jointly passes through the second small hole (25) of the second valve rod (5) and the first small hole (24) of the first valve rod (3) to continue to charge the brake cylinder (16).

Images