Railway wagon parking brake device and control method thereof

Abstract

The application discloses a parking brake device for a railway freight car and a control method thereof, and relates to the technical field of railway freight car braking, which comprises a parking brake control valve, three communication ports, a main branch pipe, a train main pipe, a wedge retreat prevention mechanism, a connecting rod, a box body, a brake lever and a driving cylinder.

Description

Technical Field

[0001] This invention belongs to the field of railway freight car braking technology, and more specifically, relates to a parking brake device for railway freight cars and its control method. Background Technology

[0002] As a primary freight transport vehicle, railway freight cars are subject to numerous marshalling, demarcation, and remarshalling operations due to the variety and demand of domestic transported goods. Currently, hump yard mechanical marshalling and locomotive-traction marshalling are commonly used in train marshalling. Regardless of the marshalling method, railway freight trains need to maintain braking while parked to prevent accidental runaway and related safety incidents. Furthermore, freight trains often use locomotives to pull trains weighing over 5000 tons, resulting in a large number of cars and a long marshalling length, exceeding 700 meters. As the traction tonnage increases, the train length also increases; for example, a 10,000-ton freight train can be nearly two kilometers long. Freight trains need to stop and wait at stations for extended periods during arrival, departure, and operation, requiring the application of parking brakes. However, parking (preventing runaway) of railway freight cars in a non-powered state primarily relies on traditional manual brakes (handbrakes) or wheel chocks / wheel stops. This method presents the following significant problems: (1) Inefficient and labor-intensive When performing anti-runaway operations on a large number of vehicles in a marshalling yard or dedicated line, shunting personnel need to operate on each vehicle individually, which is time-consuming and labor-intensive. (2) Safety depends on human factors It is easy for the handbrake to be left loose or not tightened properly, or for the metal shoe to be left out or misplaced, which poses a significant safety hazard of the vehicle rolling away. (3) Low level of automation It cannot be integrated with modern train control systems and is not suitable for the automatic parking of entire freight trains on slopes.

[0003] To solve the above problems, it is necessary to develop an automatic parking brake device that does not rely on external power. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies by providing a parking brake device and its control method for railway freight cars. This braking device automatically applies parking brakes under specific conditions such as when the train is stationary or when the pressure in the main air pipe changes, and automatically releases the brakes before the train starts moving, thereby greatly improving the safety and operational efficiency of parking railway freight cars.

[0005] To achieve the above objectives, the present invention provides a parking brake device for railway freight cars, comprising: The parking brake control valve has three connection ports: the first connection port is connected to the main branch pipe, the second connection port is connected to the parking cylinder, and the third connection port is connected to the drive cylinder. The parking brake control valve is also equipped with an openable and closable exhaust port. The main branch pipe is connected to the train main pipe. The wedge block anti-reverse mechanism includes a housing and a connecting rod. One end of the connecting rod is inserted into the inside of the housing. The connecting rod moves telescopically relative to the housing. The portion of the connecting rod inside the housing has a long through hole. When the drive cylinder is in the extended state, the telescopic end of the drive cylinder is inserted into the long through hole. The other end of the connecting rod is connected to one end of the brake lever via a pin.

[0006] Preferably, the system further includes a first tee and a second tee, wherein the top and one end of the first tee are respectively connected to the first connecting port and the main branch pipe, one end and the top of the second tee are respectively connected to the parking cylinder and the second connecting port, and the other end of the second tee is connected to the other end of the first tee through a one-way valve.

[0007] Preferably, the device further includes a third three-way connector, the two ends of which are respectively connected to the third connecting port and the driving cylinder, and the top of the third three-way connector is connected to a manual valve, which is a delayed-closing control valve.

[0008] Preferably, it also includes a reducing tee, the top and bottom of which are connected to the 120 valve and the main train pipe, respectively, and one end of the reducing tee is connected to the main branch pipe through a cut-off valve.

[0009] Preferably, the 120 valve is also connected to the auxiliary air cylinder and the brake cylinder, and the extension end of the brake cylinder is provided with a push rod, which is hinged to one end of the brake lever.

[0010] Preferably, the middle part of the brake lever is rotatably disposed at one end of the brake adjuster, and the other end of the brake lever is hinged to the pull rod.

[0011] Preferably, the parking brake control valve is provided with a pilot pressure. When the pressure of the main branch pipe is greater than the pilot pressure, the passage between the parking cylinder and the drive cylinder is cut off, and the drive cylinder is connected to the exhaust port of the parking brake control valve. When the pressure in the main branch pipe is greater than the pilot pressure, the parking cylinder is connected to the drive cylinder.

[0012] The present invention also provides a parking brake control method for railway freight cars, utilizing the above-mentioned parking brake device for railway freight cars, the control method comprising: When the train sends a braking command, the brake cylinder drives the push rod to extend outward. The push rod, brake lever and connecting rod move in sync. At the same time, because the air pressure in the train main pipe is lower than the pilot pressure of the parking brake control valve, the parking cylinder inflates the drive cylinder. The extension end of the drive cylinder is inserted into the long through hole of the connecting rod. When the train sends a release command, the air in the brake cylinder is expelled. At the same time, because the air pressure in the train main pipe is higher than the pilot pressure of the parking brake control valve, the drive cylinder is vented through the exhaust port on the parking brake control valve. Under the action of the spring force inside the cylinder, the drive cylinder drives the telescopic end to be pulled out from the long through hole of the connecting rod.

[0013] Preferably, when the train sends a braking command, the air pressure in the main train decreases, and the gas in the auxiliary air cylinder enters the brake cylinder through the 120 valve. The brake cylinder drives the push rod to extend outward, and the push rod drives the brake lever to move together. Under the joint conversion of the brake lever and the brake adjuster, the pull rod pulls the bogie basic braking device, and finally the upper brake shoe of the bogie basic braking device is pressed against the wheel. When the train sends a release command, the air pressure in the main train increases, and the gas in the main train enters the auxiliary air cylinder through valve 120. The push rod of the brake cylinder loses its outward extension force, and the wheels push the push rod of the brake cylinder back to its original position by their own power.

[0014] Preferably, when the extension end of the drive cylinder is not pulled out from the long through hole of the connecting rod after the train sends a relief command, it is necessary to first close the cut-off plug on the main branch pipe, and then move the handle of the manual valve to drive the air in the cylinder to be vented through the manual valve.

[0015] This invention provides a parking brake device and its control method for railway freight cars, which has the following advantages: 1. This braking control device can be added to the existing railway freight car braking system. Through components such as parking brake control valve, parking air cylinder, and drive cylinder, it realizes the automatic application, automatic maintenance, and automatic release of vehicle braking force in the train, thereby reducing manual intervention and improving the automation level and efficiency of parking brake. 2. This braking control device utilizes the pressure changes of the existing train main pipe as the air circuit signal for applying and releasing the parking brake, and has good compatibility. 3. The braking control device uses the pressure setting of the parking brake control valve. When parking braking force is applied, the extension and retraction of the drive cylinder push rod can be adjusted to realize the action of the wedge block, thereby locking or releasing the parking braking force. The system has a fast response and is suitable for parking on long slopes and group parking. 4. This braking control device adopts the parking brake principle of brake cylinder push rod stop, which means that the magnitude of the braking force maintained by the train depends on the braking force from the start of braking until the train stops. The greater the braking force when stopping, the greater the holding braking force. Therefore, after the vehicle has come to a complete stop, the driver can further increase the braking force by applying additional pressure relief braking, thereby increasing the parking braking force. This is beneficial for stopping the train on slopes of different gradients and preventing the train from rolling away. At the same time, the brake cylinder push rod stop parking brake device avoids the process of the push rod in the accumulator parking brake system compressing the spring as it moves with the existing vehicle's brake cylinder push rod, reducing the loss of braking pressure. Since the accumulator parking brake needs to ensure stopping on steep slopes, the required braking force requires a larger parking accumulator and a larger spring, which inevitably leads to a larger weight. This contradicts the design concept of keeping the freight car's weight as light as possible. However, the brake cylinder push rod stop parking brake utilizes the braking force of the existing vehicle's brake cylinder, thus reducing the weight. 5. The main branch pipe in this braking control device is connected to the main train pipe of the existing freight car, so that the pressure change of the main train pipe can be transmitted to the parking brake control valve of the parking brake device. At the same time, it can reduce the impact on the main train pipe as a signal transmission pipeline, which has a smaller impact on the braking and speed reduction of the train's positive braking system, thus ensuring the safe operation of long freight trains. 6. The braking control device has a manual valve between the parking brake control valve and the drive cylinder. When the parking brake system fails and the wedge cannot disengage from the long through hole, the pressurized air in the drive cylinder can be quickly released through the manual valve. Under the action of the spring force in the drive cylinder, the wedge quickly disengages from the long through hole, thereby avoiding the vehicle's poor handling caused by this situation. This allows for rapid emergency handling during train inspection and ensures that the train runs on time.

[0016] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0017] The above and other objects, features and advantages of the present invention will become more apparent from the more detailed description of exemplary embodiments of the invention in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same components in the exemplary embodiments of the invention.

[0018] Figure 1 A schematic diagram of a parking brake device for railway freight cars according to the present invention is shown.

[0019] Figure 2 A schematic diagram of a parking brake device for railway freight cars according to the present invention is shown when braking is applied.

[0020] Figure 3A schematic diagram of a parking brake device for railway freight cars according to the present invention is shown when the brake is released.

[0021] Figure 4 A schematic diagram of a parking brake device module according to an embodiment of the present invention is shown.

[0022] Explanation of reference numerals in the attached figures: 1. Parking cylinder; 2. Manual valve; 3. Parking brake control valve; 4. Check valve; 5. Brake cylinder push rod; 6. First tee; 7. Brake cylinder; 8. Main branch pipe; 9. Cut-off valve; 10. 120 valve; 11. Train branch pipe; 12. Reducing tee; 13. Branch pipe; 14. Drive cylinder; 15. Wedge block anti-reverse mechanism; 16. Connecting rod; 17. Upper pull rod; 18. Train main pipe; 19. Brake adjuster; 20. Auxiliary air cylinder; 21. Front brake lever; 22. Second tee; 23. Third tee; 24. Wedge; 25. Brake main pipe module; 26. Combined dust collector; 27. Double chamber air cylinder; 28. Weighing mechanism; 29. ​​Pressure limiting valve; 30. 120 valve module; 31. Parking brake device module; 32. Brake cylinder module. Detailed Implementation

[0023] Preferred embodiments of the invention will now be described in more detail. While preferred embodiments of the invention are described below, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the invention will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0024] First, let's determine the main parameters for the parking brake device. For existing 70t general-purpose freight cars in my country, calculated with a total weight of 95t, the downward force of a single car on a 30‰ slope is 28kN. If the parking brake can ensure the vehicle doesn't slip, the total brake shoe pressure needs to be 74kN, then the brake cylinder pressure needs to be ≥160kPa. For an empty 25t car, the downward force of a single car on a 30‰ slope is 7.5kN. If the parking brake can ensure the vehicle doesn't slip, the total brake shoe pressure needs to be 19kN, then the brake cylinder pressure needs to be ≥60kPa. To avoid energy loss caused by the brake lever driving the spring accumulator during braking and release of railway freight cars, and to solve the problem of no attenuation of the brake cylinder pressure (600kPa constant pressure, 430kPa maximum pressure in loaded condition (220kN total brake shoe pressure) and 160kPa maximum pressure in empty condition (60kPa total brake shoe pressure)). The parking brake device protected in this application employs a rear-lock mechanism applied after braking in existing vehicle braking systems, ensuring that the brake levers of railway freight cars remain in the braking state and do not retract. When the vehicle needs to be released, the rear-lock mechanism is released, thereby releasing the vehicle's parking brake and allowing the vehicle to move freely.

[0025] like Figure 1 and Figure 4 As shown, the present invention provides a parking brake device for railway freight cars, comprising: The parking brake control valve 3 is provided with three connection ports. The first connection port is connected to the main branch pipe 8, the second connection port is connected to the parking cylinder 1, and the third connection port is connected to the drive cylinder 14. The parking brake control valve 3 is also provided with an openable and closable exhaust port. The main branch pipe 8 is connected to the train main pipe 18. The wedge block anti-reverse mechanism 15 includes a housing and a connecting rod 16. The left end of the connecting rod 16 is inserted inside the housing. The connecting rod 16 moves telescopically relative to the housing. The part of the connecting rod 16 inside the housing is provided with a long through hole. When the drive cylinder 14 is in the extended state, the telescopic end of the drive cylinder 14 is inserted into the long through hole. The right end of the connecting rod 16 is connected to the upper end of the front brake lever 21 by a round pin.

[0026] Specifically, this braking device is connected to the existing railway freight car braking system, specifically the wind-driven braking system and the basic lever braking system. The wind-driven braking system includes a 120 valve 10, a brake cylinder 7, an auxiliary air cylinder 20, an acceleration-releasing air cylinder, a pressure-reducing chamber, a branch pipe, and connectors. The basic lever braking system includes a front brake lever 21, a control lever, a brake adjuster 19, a rear brake lever, an upper pull rod 17, and the bogie basic brake. This braking device connects the parking brake control valve 3 to the main branch pipe 8, the parking cylinder 1, and the drive cylinder 14, and an exhaust port is provided on the parking brake control valve 3. When the train sends a braking command, the signal is transmitted through the pressure adjustment of the train main pipe 18. The air pressure in the train main pipe 18 will decrease. Since the train main pipe 18 is connected to the main branch pipe 8, the air pressure in the main branch pipe 8 will also decrease. Upon receiving the signal of decreased air pressure, the parking brake control valve 3 adjusts the internal connection mode, connecting the parking cylinder 1 to the drive cylinder 14. The drive cylinder 14 can then inject pressurized air into itself, causing the extension end of the drive cylinder 14 to extend towards the wedge block anti-reverse mechanism 15. This is done as the brake cylinder push rod extends and... After the connecting rod 16 moves a certain distance in the wedge block anti-reverse mechanism 15, the telescopic end of the drive cylinder 14 can be inserted into the long through hole of the connecting rod 16. In this way, the drive cylinder 14 can lock the extension state and extension distance of the connecting rod 16. Since the connecting rod 16 can cause the front brake lever 21 to move in conjunction when it extends outward, the upper pull rod 17 is pulled by the brake adjuster 19 and the control lever under the joint conversion, so that the upper brake shoe in the bogie base brake device is pressed against the wheel, thereby causing the vehicle to decelerate or stop and finally stop at the designated position. When the train sends a release command, the control signal is still transmitted through the train main pipe 18 and the main branch pipe 8. The air pressure in the train main pipe 18 and the main branch pipe 8 rises rapidly. After receiving the signal of cylinder rise, the parking brake control valve 3 cuts off the air passage connecting the parking cylinder 1 and the drive cylinder 14, and connects the drive cylinder 14 to the exhaust port of the control valve. In this way, the gas in the drive cylinder 14 is discharged, and the extension end of the drive cylinder 14 will retract until the extension end of the drive cylinder 14 is completely disengaged from the long through hole of the connecting rod 16. At the same time, the gas in the brake cylinder 7 is discharged through the 120 valve 10. The connecting rod 16 has no other structural limit and no support force from the brake cylinder 7. In this way, under the traction of the locomotive, the train can move slowly. The upper brake shoe that was originally against the wheel is pushed open, the connecting rod 16 connected to the brake cylinder push rod is pushed back to its original position, and the brake cylinder 7 switches to the compressed state.

[0027] To ensure assembly efficiency and quality, the parking brake control valve 3, parking cylinder 1, wedge block anti-reverse mechanism 15, drive cylinder 14, manual valve 2, and one-way valve 4 are all uniformly arranged on the parking brake module mounting plate. Simultaneously, the connecting pipes for each component on this module are pre-assembled, allowing for complete installation on the vehicle. This braking device can operate simultaneously when the railway freight train is stopped, maintaining braking force and enabling the train to stop steadily on a 30‰ gradient without slipping. Furthermore, it maintains a certain braking force when the train starts, ensuring that the train can start and maintain forward movement under the locomotive's traction.

[0028] The wedge block anti-reverse mechanism 15 of this braking device adopts a certain angled slope design, which can adapt to the change in the stroke of the brake cylinder push rod caused by the wear of the brake shoes. When the stroke of the brake cylinder push rod increases, the wedge block 24 falls in more, which can maintain the anti-reverse effect under the increased stroke, thus ensuring that the braking force does not decrease. The design position of the long through hole in the wedge block anti-reverse mechanism 15 fully considers the maximum and minimum stroke of the brake cylinder push rod under the vehicle's empty and loaded conditions. Based on the test results, the long through groove on the connecting rod 16 is designed between 145mm and 175mm when the brake cylinder push rod is extended, thus meeting the requirements of maintaining the braking force of the vehicle under various loads.

[0029] In existing railway freight car braking systems, there is a brake adjuster 19 that automatically adjusts the lever angle as the brake shoes wear down during vehicle operation, thereby ensuring that the pressure and stroke of the brake cylinder 7 remain constant. The design of the wedge block anti-reverse mechanism 15 allows the depth of the wedge block falling into the long through hole to change with the change of the brake shoes. When the brake shoes are replaced, and braking and release are performed again, when the brake adjuster 19 adjusts the brake lever angle, the wedge block 24 will not affect the adjustment action of the brake adjuster 19, thereby ensuring that the brake cylinder 7 can return to its original position, thus ensuring the braking effect of the existing vehicles.

[0030] Preferably, it also includes a first tee fitting 6 and a second tee fitting 22. The top and right end of the first tee fitting 6 are connected to the first connecting port and the main branch pipe 8, respectively. The left end and top of the second tee fitting 22 are connected to the parking cylinder 1 and the second connecting port, respectively. The right end of the second tee fitting 22 is connected to the left end of the first tee fitting 6 through a one-way valve 4.

[0031] Preferably, it also includes a third three-way connector 23, the right end and the left end of the third three-way connector 23 being connected to the third connecting port and the driving cylinder 14 respectively, and the top of the third three-way connector 23 being connected to the manual valve 2, which is a delayed closing control valve.

[0032] Specifically, the parking brake control valve 3 has three passages, which are connected to the main branch pipe 8, the parking cylinder 1, and the drive cylinder 14, respectively. A third three-way connector 23 is provided on the pipe connecting the control valve and the drive cylinder 14. This third three-way connector 23 is also connected to a manual valve 2. A branch pipe 13 is connected to the parking cylinder 1. The branch pipe 13 is connected to the control valve through a second three-way connector 22. The main branch pipe 8 is connected to the control valve through a first three-way connector 6. A one-way valve 4 is also provided between the first three-way connector 6 and the second three-way connector 22. In this way, the pressure change of the train main pipe 18 will be transmitted to the parking brake control valve through the main branch pipe 8, thereby realizing the extension and retraction of the drive cylinder 14. Finally, the connection relationship between the extension end of the drive cylinder 14 and the connecting rod 16 is realized, that is, the positional relationship of plug-in fixation or separation.

[0033] The parking brake control valve 3 can be considered as a two-position three-way pressure pilot valve. When the pressure value of the train main pipe 18 is higher than the pilot pressure, the control valve will cut off the passage between the parking cylinder 1 and the drive cylinder 14. At the same time, the passage of the drive cylinder 14 is connected to the atmosphere through the parking brake control valve 3, and the gas inside the drive cylinder 14 is discharged. When the pressure value is lower than the pilot pressure, the parking brake control valve 3 will activate after a delay of 0.5 seconds, connecting the passage between the parking cylinder 1 and the drive cylinder 14. The drive cylinder 14 can be considered as a one-way cylinder. When pressurized air enters the cylinder, the extension end of the drive cylinder 14 extends, but when the pressurized air is discharged, the extension end of the drive cylinder 14 retracts. The manual valve 2 adopts a time-delayed closing manual valve 2, which closes the exhaust passage of the manual valve 2 after a 30-second delay after manually opening the exhaust passage.

[0034] The one-way valve 4 between the first three-way component 6 and the second three-way component 22 is a one-way valve 4 with a pressure spring. This ensures that the pressurized air in the parking cylinder 1 will not flow back into the main branch pipe 8, thus avoiding affecting the release function of the existing freight train. It also ensures that the pressure transmission of the train main pipe 18 is first transmitted to the existing vehicle 120 control valve braking system, without affecting the existing railway freight car braking system.

[0035] Preferably, it also includes a reducing tee 12, the top and bottom of which are connected to the 120 valve 10 and the train main pipe 18 respectively, and the left end of the reducing tee 12 is connected to the main branch pipe 8 through a cut-off plug 9.

[0036] Preferably, valve 10 is also connected to auxiliary air cylinder 20 and brake cylinder 7. The extension end of brake cylinder 7 is provided with brake cylinder push rod, which is hinged to the upper end of front brake lever 21.

[0037] Specifically, the upper, lower and left ends of the reducing tee 12 are connected to the 120 valve 10, the auxiliary air cylinder 20 and the main branch pipe 8, respectively. When the train main pipe 18 adjusts the internal air pressure according to the train instructions, the 120 valve 10 will also receive the air pressure change signal from the train main pipe 18. The 120 valve 10 will convert it into a control command to adjust the connection between the brake cylinder 7 and the auxiliary air cylinder 20. When the air pressure in the main train duct 18 decreases, the gas in the auxiliary air cylinder 20 is injected into the brake cylinder 7 through valve 120. This allows the brake cylinder push rod to extend, which, in addition to driving the connecting rod 16 to insert into the wedge block anti-reverse mechanism 15, also drives the front brake lever 21 and the upper pull rod 17 to move, causing the upper brake shoe to press against the wheel. When the air pressure in the main train duct 18 increases, the gas in the main train duct 18 is injected into the auxiliary air cylinder 20 through valve 120. At the same time, the brake cylinder 7 vents its internal gas through valve 120. This allows the auxiliary air cylinder 20 to reserve gas for the next train braking. As the gas inside the brake cylinder 7 is vented, the brake cylinder push rod 5 loses its support. As the wheel moves, the upper brake shoe is pushed open, and the brake cylinder push rod 5 is pushed back to its original position.

[0038] Preferably, the middle part of the front brake lever 21 is rotatably disposed at the left end of the brake adjuster 19, the lower end of the front brake lever 21 is hinged to the upper pull rod 17, and the right end of the brake adjuster 19 is hinged to the rear brake lever.

[0039] Specifically, since this application protects the parking brake device, the structure of the basic lever braking system adopts existing structures. This application only describes the connection structure of the front brake lever 21, which is linked to the brake cylinder push rod and connecting rod 16, and the movement of the front brake lever 21, brake adjuster 19, and upper pull rod 17 under the extension and retraction of the drive cylinder 14 and the brake cylinder 7. The rear brake lever connected to the right end of the brake adjuster 19 is only shown in the figure. In the figure, the upper end of the rear brake lever covers the pipeline between the brake cylinder 7 and the 120 valve 10, and the rear brake lever and lower pull rod cover part of the train main pipe 18.

[0040] Preferably, the parking brake control valve 3 is provided with a pilot pressure. When the pressure of the main branch pipe 8 is greater than the pilot pressure, that is, when the train sends a release command, the passage between the parking cylinder 1 and the drive cylinder 14 is cut off, and the drive cylinder 14 is connected to the exhaust port of the parking brake control valve 3. When the pressure in the main branch pipe 8 is greater than the pilot pressure, that is, when the train sends a braking command, the parking cylinder 1 is connected to the drive cylinder 14.

[0041] Specifically, the parking brake control valve 3 is equipped with a pilot pressure. It is also connected to the train main pipe 18 via the main branch pipe 8 and the reducing tee 12. When the train issues a braking command, the air pressure in the train main pipe 18 decreases, resulting in the parking brake control valve 3 obtaining a lower air pressure in the train main pipe 18 than the pilot pressure. This allows the parking cylinder 1 and the drive cylinder 14 to be connected for air supply. When the train issues a release command, the train main pipe 18 provides pneumatic power to the entire train, resulting in the parking brake control valve 3 obtaining a higher air pressure in the train main pipe 18 than the pilot pressure. This switches the parking cylinder 1 and drive cylinder 14 to a short-term state, and the gas in the drive cylinder 14 is discharged. The parking brake control valve 3 can control the extension and retraction of the drive cylinder 14 based on the gas pressure change signal. During train braking, the connecting rod 16 is locked to ensure the brake shoes are in contact with the wheels. The movement of the connecting rod 16 is not affected by gas leakage in the brake cylinder 7, thus improving train braking stability.

[0042] like Figure 2 and Figure 3 As shown, the present invention also provides a parking brake control method for railway freight cars, utilizing the aforementioned parking brake device for railway freight cars. The control method includes: When the train sends a braking command, the brake cylinder 7 drives the brake cylinder push rod to extend outward. The brake cylinder push rod, the front brake lever 21 and the connecting rod 16 move in sync. At the same time, because the air pressure in the train main pipe 18 is lower than the pilot pressure of the parking brake control valve 3, the parking cylinder 1 inflates the drive cylinder 14. The extension end of the drive cylinder 14 extends outward and is inserted into the long through hole of the connecting rod 16. When the train sends a release command, the air in the brake cylinder 7 is discharged. At the same time, because the air pressure in the train main pipe 18 is higher than the pilot pressure of the parking brake control valve 3, the gas in the drive cylinder 14 is discharged through the exhaust port on the parking brake control valve 3. Under the action of the spring force inside the cylinder, the drive cylinder 14 drives the telescopic end to be pulled out from the long through hole of the connecting rod 16.

[0043] Preferably, when the train sends a braking command, the air pressure in the train main pipe 18 decreases, and the gas in the auxiliary air cylinder 20 enters the brake cylinder 7 through the 120 valve 10. The brake cylinder 7 drives the brake cylinder push rod to extend outward, and the brake cylinder push rod drives the brake lever to move to the left. Under the joint conversion of the brake lever and the brake adjuster 19, the upper pull rod 17 pulls the bogie basic braking device, and finally the upper brake shoe of the bogie basic braking device is pressed against the wheel. When the train sends a release command, the air pressure in the train main pipe 18 increases, and the gas in the train main pipe 18 enters the auxiliary air cylinder 20 through the 120 valve 10. The gas in the brake cylinder 7 is vented, so that the push rod of the brake cylinder 7 loses the force to extend outward. The wheel uses its own power to push the upper brake shoe and the push rod of the brake cylinder 7 back to their original positions.

[0044] Specifically, the parking brake application principle is as follows: The pressure of the parking brake control valve 3 in the parking brake device is set to 500 kPa. Currently, the pressure of the train main pipe 18 is set to 600 kPa. That is, when the train is running and starting, the pressure of the train main pipe 18 is 600 kPa. The pressure of the air in the auxiliary air cylinder 20 and the acceleration and release air cylinder in the vehicle braking system is 600 kPa, and the pressure of the air in the brake cylinder 7 is zero. The brake cylinder push rod is in the retracted state, and the entire train is in the released state. At the same time, the parking cylinder 1 is also charged to 600 kPa through the main branch pipe 8. At this time, the pressure of the train main pipe 18 is greater than the pilot pressure set by the parking brake control valve 3. The passage between the parking cylinder 1 and the drive cylinder 14 is disconnected. At the same time, the passage of the drive cylinder 14 is connected to the exhaust port of the parking brake control valve 3. The parking brake device does not work. When the train needs to stop, the locomotive reduces the pressure in the train main pipe 18. When the pressure reduction value is greater than 100 kPa, valve 10 in the vehicle's air brake system activates, connecting the auxiliary air cylinder 20 with the brake cylinder 7 to allow air intake. This pushes the brake cylinder push rod to extend, which in turn moves the front brake lever 21. Under the combined action of the brake adjuster 19 and the control lever, the upper pull rod 17 pulls the bogie base brake device, causing the brake shoes of the bogie base brake device to press against the wheels, thus slowing down the vehicle and bringing it to a quick stop. At this time, because the pressure in the train main pipe 18 is below 50 kPa... When the pressure reaches 0 kPa, the parking brake control valve 3 is activated, connecting the parking cylinder 1 and the drive cylinder 14. Pressurized air enters the drive cylinder 14 from the parking cylinder 1, causing the extension end of the drive cylinder 14 to extend and push the wedge 24 against the connecting rod 16. Since the connecting rod 16 is connected to the brake cylinder push rod, when the brake cylinder push rod presses the brake shoes against the wheel, the total pressure of the vehicle's brake shoes exceeds the requirement of 160 kN for a loaded vehicle and 60 kN for an empty vehicle. Simultaneously, the wedge 24 extends into the long through hole of the connecting rod 16, preventing the brake cylinder push rod from retracting and maintaining the total pressure of the vehicle's brake shoes. Because a one-way valve 4 is installed between the parking air cylinder and the train branch pipe 11, a further decrease in the pressure of the train main pipe 18 will not cause a change in the pressure of the parking air cylinder. The parking air cylinder will always maintain the extended state of the drive air cylinder push rod, thus ensuring continuous parking brake operation. Even if the pressure of the compressed air in the brake cylinder 7 is insufficient, the total pressure of the vehicle's brake shoes will not decrease. In this way, all vehicles in the train have parking braking force, and can eventually stop safely and reliably at the designated position.

[0045] Parking brake release principle: When the train needs to start, the locomotive first issues a release command, charging 600kPa pressurized air into the train main pipe 18. As the pressurized air pressure in the train main pipe 18 increases, the parking brake control valve 3 quickly returns to its original position, cutting off the pressurized air in the parking air cylinder. At the same time, the drive cylinder 14 is connected to the outside atmosphere through the parking brake control valve 3. Under the action of the spring force inside the cylinder, the drive cylinder 14 drives the wedge block 24 to move upward, disengaging from the long through hole of the connecting rod 16. The brake cylinder push rod is released in the wedge block anti-retraction mechanism 15. At the same time, the 120 valve 10 also acts quickly, and the brake cylinder 7 vents the pressurized air through the 120 valve 10. Simultaneously, the 120 valve 10 connects the train main pipe 18 with the auxiliary air cylinder 20, thereby charging the auxiliary air cylinder 20. At this time, the vehicle is in the released state. Under the traction of the locomotive, the train can move slowly and the wheel power pushes the brake cylinder push rod back to its original position.

[0046] The control pressure of the parking brake device is set at 500 kPa for the main train pressure, which can adapt to the existing train driver operating habits and meet the requirements of depressurization braking and stage depressurization braking during train operation. At the same time, since the parking brake does not work when the depressurization is less than 100 kPa, the basic functions of the train, such as general ground braking and depressurization, are not affected, and the safe operation of the vehicle can be guaranteed.

[0047] Preferably, when the extension end of the drive cylinder 14 is not pulled out from the long through hole of the connecting rod 16 after the train sends a relief command, it is necessary to first close the cut-off plug 9 on the main branch pipe 8, and then move the handle of the manual valve 2 so that the air in the drive cylinder 14 is vented through the manual valve 2.

[0048] Specifically, according to the "Railway Freight Car Operation and Maintenance Regulations," a train must undergo a full departure test upon departure. When the train applies a release signal, the locomotive charges the train pipe with 600 kPa pressurized air. The pressurized air in the brake cylinders 7 of all the train vehicles should be emptied, and the extension end of the drive cylinder 14 of the parking brake device should retract. The wedge 24 should disengage from the long through hole of the connecting rod 16, and the entire vehicle should be in a released state. However, the train inspection operation still requires checking the released state of the train vehicles. If any vehicles are found to be not released, the brakes must be manually released, and simple troubleshooting should be performed to allow the train to run. If it is found that the wedge 24 in the parking brake device has not disengaged from the long through hole of the connecting rod 16, the cut-off plug 9 on the main branch pipe 8 of the parking brake device should be closed, and then the handle of the manual valve 2 should be turned. At this time, the pressurized air in the drive cylinder 14 is emptied, and the piston rod of the drive cylinder 14 retracts under the action of the cylinder spring. The wedge 24 will automatically disengage from the long through hole of the connecting rod 16, and the brake cylinder push rod will be in a relaxed state, thereby releasing the vehicle. Since manual valve 2 is a delayed return valve, after the handle of manual valve 2 is turned for 30 seconds, the manual valve 2 returns to its original position under the action of the spring inside the manual valve 2, thus closing the exhaust passage through manual valve 2.

[0049] Furthermore, the main branch pipe 8 and all branch pipes in this parking brake device are made of DN15 pipe with a diameter of 15mm. This utilizes common railway freight car piping, and its diameter has minimal impact on train speed reduction. The pipe connections employ the flange connection method commonly used in existing vehicles, ensuring the sealing of the piping between the parking brake devices and meeting existing vehicle maintenance requirements. All seals and lubricants within the parking brake device use rubber components and greases common to railway freight cars, meeting the requirements of existing vehicle operating environments. This allows for 24-hour uninterrupted operation and stable functioning even in harsh environments (such as rain, snow, and temperature variations between north and south), reducing the labor intensity and cost of manual inspections. This makes it suitable for the operating environment requirements of railway freight cars.

[0050] The driving cylinder 14 of the parking brake device features a red marking line and a yellow base plate to indicate the disengagement of the wedge block 24 from the long through hole in the wedge block anti-retraction mechanism 15. This design allows train inspectors to easily observe whether the parking brake is in the parking or released state during train inspections, ensuring the train operates without brakes and preventing issues such as hot wheels and abrasions. The extension end of the driving cylinder 14 is marked with a red marking line; when the extension end returns to the marked position, it clearly indicates that the wedge block 24 has disengaged from the long through slot of the connecting rod 16 and is in the released state.

[0051] The technical problems solved by this parking brake device include: 1. The parking brake device must first be different from the spring accumulator used in existing locomotives, possessing novelty, avoiding energy loss caused by the brake lever driving the spring accumulator when braking and releasing railway freight cars, and solving the problem of no attenuation when the constant pressure of the railway freight car is 600kPa, the maximum pressure of the brake cylinder in the loaded car state is 430kPa (total pressure of brake shoes is 220kN), and the maximum pressure of the brake cylinder in the unloaded car state is 160kPa (total pressure of brake shoes is 60kN); 2. This parking brake device addresses the issues of triggering and releasing the parking brake. Currently, freight trains primarily rely on pressure changes in the train pipe to achieve braking and release functions. Since the train's constant pressure is 600 kPa, various situations arise during train operation, including phased braking, phased release, and stopping braking. Generally, during phased braking, the train pipe pressure is reduced by 60 kPa, with a maximum reduction to 80 kPa. Simultaneously, when the train is parked, there are both pressurized and depressurized air conditions in the train pipe. When 600 kPa of pressurized air is introduced into the train pipe, the vehicle needs to release the brake if the pressure increases by only 50 kPa. Therefore, it is necessary to study how to determine the triggering and releasing timing of the parking brake device without affecting these operational requirements. 3. This parking brake device solves the problem of signal transmission for triggering and releasing the parking brake. Since freight trains are long and railway freight cars are not powered, the signal transmission of the railway freight car braking system is based on the pressure change of the train pipe. Therefore, the application and release of the parking brake device can only be based on the pressure change of the train pipe. At the same time, considering the influence of the train pressure air propagation speed factor, the design of the parking brake device also needs to solve the problem of the impact on braking and mitigation wave speed. 4. This parking brake device solves the problem of the conversion mechanism inside the device. By changing the pressure of the main train pipe, a set of efficient and reliable pneumatic-mechanical energy conversion mechanism (such as cylinder and piston) is studied. It can connect the pressurized air of the train pipe to the energy storage device through the air path conversion of the control valve, forming an energy storage device for the parking brake device, and can convert the air path to drive the piston or actuator cylinder. 5. This parking brake device addresses the problem of the parking brake actuator by designing a mechanical force amplification mechanism that can directly act on the existing basic braking device of the truck (such as the brake lever) to ensure that its output force is sufficient to lock the wheels and has a self-locking function to prevent the vehicle from being released unexpectedly. 6. The research on this parking brake device is based on a purely mechanical time delay module with damping or gear transmission, ensuring that braking is applied only after the train has come to a stable stop; 7. The parking brake device needs to solve the problem that when the main air pipe pressure returns to the operating standard, the device itself can automatically switch the air path to drive the actuator to unlock and lock the mechanism, thereby relieving the entire train's pressure. 8. The parking brake device needs to be designed with a mechanism for manual emergency application and manual release according to the needs of train inspection operations, so as to ensure that when the parking brake device fails to automatically activate, personnel can still control the vehicle's braking force and release the vehicle as if operating a traditional handbrake. 9. The parking brake device must address the issue of safety and reliability, ensuring that the device will never malfunction during vehicle operation and that the release state is absolutely reliable. 10. Due to the complex operating environment of railway freight cars, and the requirement for ambient temperature between -40℃ and 50℃, the design and material selection of parking brake devices must consider low-temperature resistant, impact-resistant, and corrosion-resistant metal materials to adapt to my country's complex geographical and climatic conditions. 11. Due to the location of the braking devices on railway freight cars, there may be obstructions to the parking brake devices. However, the inspection of the vehicle braking system is a must during train inspection. Therefore, a clear display device must be provided to facilitate observation by train inspection personnel.

[0052] 12. This parking brake device solves the problem of adapting to various braking structures of railway freight cars. Since railway freight cars have basic multi-lever braking devices and integrated braking devices, the designed parking brake device needs to take into account the structural types of various existing braking devices, and can be installed conveniently and quickly.

[0053] Finally, the main difficulties encountered in the design process of this application are: a. Determining the overall technical approach: First, study the overall structural configuration of automatically applying the parking brake and automatically releasing it before the train starts; b. The designed device must meet the following test requirements according to the "Railway Freight Car Operation and Maintenance Regulations": (1) Leakage test: Close the front angle plug of the first car, maintain the pressure of the train piping for 1 minute, and the pressure drop of the main train pipe displayed by the wireless wind pressure monitor should not exceed 20 kPa. After the test, open the angle plug; (2) Sensitivity test: Set to the normal braking position, reduce the pressure by 50 kPa (70 kPa when the train has more than 60 cars), the whole train must brake and should not release naturally within 1 minute. Then set to the running position to release air and the whole train should release within 1 minute; (3) Stable pressure holding test: Set to the normal braking position, reduce the pressure by 140 kPa (170 kPa when the main train pipe pressure is 600 kPa), emergency braking should not occur, and confirm that the piston stroke of the brake cylinder must meet the requirements; at the same time, maintain the pressure, and the pressure drop of the main train pipe displayed by the wireless wind pressure monitor should not exceed 20 kPa within 1 minute; (4) Pressure holding test for a certain period of time: Set to the normal braking position, reduce the pressure by 100 kPa. The pressure must be maintained for 3 minutes and must not release spontaneously; therefore, the development of parking brake devices must take into account existing testing regulations. c. At the same time, due to the long train formation, there are multiple situations during train operation, such as braking → secondary braking → release or braking → release → braking. Therefore, it is necessary to study the impact of the parking brake application signal (i.e., the selection of the pressure value) on this situation to meet the train operation requirements. d. Vehicle parking braking involves service braking, emergency braking, and a slow decrease in mains pressure after braking. To ensure stable braking and prevent runaway when no release control command is issued, release must be initiated as soon as the train's mains pressure increases. This necessitates studying the control principle that determines the pressure drop required to initiate parking braking at a constant train pressure of 600 kPa, and the release mechanism that triggers release when the train's mains pressure increases by 50 kPa.

[0054] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A parking brake device for railway freight cars, characterized in that, include: The parking brake control valve has three connection ports: the first connection port is connected to the main branch pipe, the second connection port is connected to the parking cylinder, and the third connection port is connected to the drive cylinder. The parking brake control valve is also equipped with an openable and closable exhaust port. The main branch pipe is connected to the train main pipe. The wedge block anti-reverse mechanism includes a housing and a connecting rod. One end of the connecting rod is inserted into the inside of the housing. The connecting rod moves telescopically relative to the housing. The portion of the connecting rod inside the housing has a long through hole. When the drive cylinder is in the extended state, the telescopic end of the drive cylinder is inserted into the long through hole. The other end of the connecting rod is connected to one end of the brake lever via a pin.

2. The parking brake device for railway freight cars according to claim 1, characterized in that, It also includes a first tee and a second tee. The top and one end of the first tee are connected to the first connecting port and the main branch pipe, respectively. One end and the top of the second tee are connected to the parking cylinder and the second connecting port, respectively. The other end of the second tee is connected to the other end of the first tee through a one-way valve.

3. The parking brake device for railway freight cars according to claim 2, characterized in that, It also includes a third tee fitting, the two ends of which are connected to the third connecting port and the driving cylinder respectively, and the top of the third tee fitting is connected to the manual valve.

4. The parking brake device for railway freight cars according to claim 3, characterized in that, It also includes a reducing tee, the top and bottom of which are connected to the 120 valve and the main train pipe, respectively, and one end of the reducing tee is connected to the main branch pipe through a cut-off valve.

5. The parking brake device for railway freight cars according to claim 4, characterized in that, The 120 valve is also connected to the auxiliary air cylinder and the brake cylinder. The extension end of the brake cylinder is provided with a push rod, which is hinged to one end of the brake lever.

6. The parking brake device for railway freight cars according to claim 1, characterized in that, The middle part of the brake lever is rotatably mounted at one end of the brake adjuster, and the other end of the brake lever is hinged to the pull rod.

7. The parking brake device for railway freight cars according to claim 1, characterized in that, The parking brake control valve is equipped with a pilot pressure. When the pressure of the main branch pipe is greater than the pilot pressure, the passage between the parking cylinder and the drive cylinder is cut off, and the drive cylinder is connected to the exhaust port of the parking brake control valve. When the pressure in the main branch pipe is greater than the pilot pressure, the parking cylinder is connected to the drive cylinder.

8. A parking brake control method for railway freight cars, utilizing the parking brake device for railway freight cars according to any one of claims 1-7, characterized in that, The control method includes: When the train sends a braking command, the brake cylinder drives the push rod to extend outward. The push rod, brake lever and connecting rod move in sync. At the same time, because the air pressure in the train main pipe is lower than the pilot pressure of the parking brake control valve, the parking cylinder inflates the drive cylinder. The extension end of the drive cylinder is inserted into the long through hole of the connecting rod. When the train sends a release command, the air in the brake cylinder is expelled. At the same time, because the air pressure in the train main pipe is higher than the pilot pressure of the parking brake control valve, the drive cylinder is vented through the exhaust port on the parking brake control valve. Under the action of the spring force inside the cylinder, the drive cylinder drives the telescopic end to be pulled out from the long through hole of the connecting rod.

9. The parking brake control method for railway freight cars according to claim 8, characterized in that, When the train sends a braking command, the air pressure in the main train decreases, and the gas in the auxiliary air cylinder enters the brake cylinder through the 120 valve. The brake cylinder drives the push rod to extend outward, and the push rod drives the brake lever to move together. Under the joint conversion of the brake lever and the brake adjuster, the pull rod pulls the bogie basic braking device, and finally the upper brake shoe of the bogie basic braking device is pressed against the wheel. When the train sends a release command, the air pressure in the main train increases, and the gas in the main train enters the auxiliary air cylinder through valve 120. The push rod of the brake cylinder loses its outward extension force, and the wheels push the push rod of the brake cylinder back to its original position by their own power.

10. The parking brake control method for railway freight cars according to claim 8, characterized in that, When the extension end of the drive cylinder fails to be pulled out of the long through hole of the connecting rod after the train sends a relief command, the cut-off plug on the main branch pipe must first be closed, and then the handle of the manual valve should be turned to vent the air in the drive cylinder through the manual valve.

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