Railway wagon bottom door pneumatic-mechanical linkage unloading control system and control method thereof

Abstract

The application discloses a railway wagon bottom door pneumatic-mechanical linkage unloading control system and a control method thereof, and belongs to the technical field of railway wagon pneumatic control and mechanical locking. The system is composed of a pneumatic control unit, a mechanical locking unit and a sensing and control system. The pneumatic control unit adopts an integrated valve body, is provided with a three-position five-way electromagnetic reversing valve and a double-pressure linkage sequence valve, and establishes hardware interlocking for driving and unlocking through pressure feedback. The mechanical locking unit coaxially arranges a driving air cylinder, an elastic cone sleeve, a pressing ring and a locking air cylinder with an embedded disc spring group, and realizes stepless locking of a piston rod at any position by radial deformation of the elastic cone sleeve. The application realizes intrinsic safety of unlocking out of position and driving never moving through pressure threshold interlocking, and the driving air cylinder is completely depressurized after locking. The position is kept by a pure mechanical structure, and the slow crawling problem of pneumatic position keeping is completely solved. The system has few valve pieces and high reliability, can realize stepless adjustment of the bottom door opening degree and zero gas consumption long-time position keeping, and is suitable for unloading control of railway hopper cars.

Description

Technical Field

[0001] This invention relates to the field of pneumatic control and mechanical locking technology for railway freight cars, and in particular to a pneumatic-mechanical linkage unloading control system and control method for the bottom door of railway freight cars. Background Technology

[0002] Railway freight car hoppers are the main type of vehicle used for transporting bulk goods such as coal, ore, and ballast. The reliable opening and closing and precise control of their bottom doors directly determine unloading efficiency, operational safety, and cargo loss. Currently, railway freight car bottom door opening, closing, and locking technologies are mainly divided into three categories: purely mechanical linkage type, pneumatic control type, and electro-hydraulic control type. Among them, the pneumatic control type can use compressed air from the train pipe as a power source, eliminating the need for an additional power unit, and is the most widely used in the field of railway freight cars.

[0003] Existing pneumatic control systems still suffer from numerous technical shortcomings in practical applications: a large number of valves, complex piping, and high maintenance costs. For example, the control system for the unloading mechanism of a slag funnel car disclosed in Chinese Patent No. CN202378878U requires more than nine independent valves, all connected by external pipelines. This not only results in a cumbersome installation layout but also numerous pipeline joints and leakage points, leading to low system reliability and a heavy workload for daily maintenance. The coupling of drive and position-holding functions presents a "slow crawling" problem. Existing pneumatic solutions often use three-position cylinders to maintain the opening, relying on continuous air pressure in each chamber to maintain the piston position. However, pneumatic systems inevitably suffer from internal leakage problems such as valve core leakage, micro-leakage at pipeline joints, and piston seal leakage. This causes the bottom door opening to gradually deviate from the set value during prolonged position-holding, failing to meet the requirements of scenarios requiring long-term position-holding, such as continuous unloading with a slightly open opening during train operation. The lack of safety interlocking between pneumatic drive and mechanical locking means that the existing bottom door opening and closing mechanism and pneumatic control system cannot achieve action interlocking. If the pneumatic control device is accidentally activated during operation, the cylinder may be forcibly driven before the locking device is unlocked, causing the transmission mechanism to jam or even be damaged. Some solutions only achieve interlocking between manual and pneumatic operation modes, not automatic interlocking between drive action and locking state, and cannot fundamentally avoid the risk of misoperation. Relying on time delay control to achieve sequential action is unreliable. Some time delay control schemes achieve action timing control through throttle valves, which is an open-loop control. Regardless of whether the locking device has been unlocked, the next drive action is executed as soon as the preset delay is reached, and it cannot be adaptively adjusted according to actual working conditions. Under the harsh working conditions of railway freight cars with vibration, dust, and large temperature differences, the throttle orifice of the time delay valve is prone to clogging, the spring is prone to fatigue, the time delay accuracy decreases, and there are safety hazards.

[0004] Meanwhile, existing mechanical locking devices also have significant shortcomings: Ratchet-pawl locking structures: the locking positions are discretely distributed due to the limited number of teeth, making stepless locking impossible; under load, the pawl is pressed against the ratchet teeth, resulting in high unlocking force and difficult manual operation; furthermore, dust easily enters the tooth surfaces, causing wear and jamming, reducing locking reliability. Stepped limiting disc structures: can only achieve gear control through a limited number of steps, cannot adjust the intermediate opening, and gear switching requires manual operation while the vehicle is stopped, making it impossible to dynamically adjust the bottom door opening during unloading. Screw limit and pin hole gear structures: also a discrete gear control method, the adjustment operation is cumbersome, requires manual intervention while the vehicle is stopped, and cannot achieve dynamic continuous adjustment during unloading. Summary of the Invention

[0005] The purpose of this invention is to provide a pneumatic-mechanical linkage unloading control system and its control method for railway freight car bottom doors. This system solves the technical problems of existing pneumatic control systems, such as numerous valves, easy drift in air pressure maintenance, lack of safety interlocking between drive and locking, and the inability of mechanical locking devices to lock steplessly, difficulty in unlocking under load, and poor environmental adaptability. The invention achieves stepless locking at any bottom door opening, long-term position maintenance with zero air consumption, and inherently safe interlocking based on pressure threshold, thereby improving system reliability and unloading control accuracy.

[0006] To achieve the above objectives, this invention provides a pneumatic-mechanical linkage unloading control system for railway freight cars, comprising a pneumatic control unit, a mechanical locking unit, and a sensing and control system. The pneumatic control unit is responsible for compressed air distribution and timing interlock control, and includes a valve body integrated block, a three-position five-way solenoid directional valve, and two dual-pressure linkage sequence valves. The three-position five-way solenoid directional valve is mounted on the valve body integrated block and has three working positions: open, closed, and Y-type functional neutral position. The valve body integrated block integrates a precision airflow channel, with an air inlet, a first air outlet, a second air outlet, a third air outlet, and an exhaust port. The air passages between each air outlet are connected inside the valve body, eliminating the need for external piping. The two dual-pressure linkage sequence valves are connected in series between the first air outlet and the rodless chamber of the drive cylinder, and between the second air outlet and the rod chamber of the drive cylinder, respectively. Each dual-pressure linkage sequence valve has a first control port and a second control port. The air passage from the first control port to the drive cylinder side can only be opened when the pressure at the second control port reaches a preset threshold, thus achieving pressure interlocking at the hardware level.

[0007] The mechanical locking unit includes a drive cylinder, an elastic conical sleeve, a compression ring, and a locking cylinder. The drive cylinder is a double-acting cylinder, with its piston rod connected to the bottom door. When the piston rod extends, it drives the bottom door to open; when the piston rod retracts, it drives the bottom door to close. Both the elastic conical sleeve and the compression ring are fitted onto the outer surface of the piston rod of the drive cylinder. The elastic conical sleeve has several through grooves along the axial direction, providing radial elastic deformation capability. The inner wall conical surface of the compression ring matches the shape of the elastic conical sleeve and can move axially. The locking cylinder contains a disc spring assembly and an unlocking chamber. The internal piston of the locking cylinder is connected to the compression ring. The disc spring assembly is normally closed. When there is no air pressure in the unlocking chamber, the disc spring assembly pushes the piston and causes the compression ring to compress the elastic conical sleeve, causing the conical sleeve to radially contract and lock the piston rod. When compressed air is introduced into the unlocking chamber, the air pressure pushes the piston to compress the disc spring assembly, causing the compression ring to release the elastic conical sleeve, and the conical sleeve radially opens to release the piston rod. The third air outlet is simultaneously connected to the unlocking chamber of the locking cylinder and the second control port of the two dual-pressure linkage sequence valves, providing unlocking air pressure to the locking unit and pressure feedback signal to the sequence valves.

[0008] The sensing and control system realizes state monitoring and closed-loop control, including a pressure sensor, a displacement sensor, and an electronic control unit. The pressure sensor is installed in the air path of the third air outlet to monitor the unlocking chamber pressure in real time; the displacement sensor is installed at the drive cylinder or the bottom door shaft to monitor the bottom door opening degree in real time; the electronic control unit receives signals from the pressure sensor and the displacement sensor and controls the position switching of the three-position five-way solenoid directional valve according to the preset control logic.

[0009] Preferably, the locking cylinder and the piston rod end of the driving cylinder are coaxially and fixedly connected; the mechanical locking unit further includes a limiting guide sleeve, which is fixedly disposed on the outer surface of the driving cylinder near the locking cylinder by a support rod; the piston rod of the driving cylinder passes through a guide hole opened at the center of the limiting guide sleeve and slides with the guide hole, and the elastic cone sleeve is fixedly disposed inside the guide hole; the compression ring slides with the piston rod of the driving cylinder and is connected to the piston inside the locking cylinder through a linkage rod; one end of the linkage rod is fixedly connected to the surface of the compression ring away from the elastic cone sleeve, and the other end seals and passes through the locking cylinder and is fixedly connected to the piston inside the locking cylinder.

[0010] Preferably, the inner wall of the elastic cone sleeve is frustoconical with an inner cone angle of 15° and the larger end faces the drive cylinder side; the elastic cone sleeve has several through grooves evenly distributed along the axial direction and an annular oil storage groove is provided on the inner wall.

[0011] Preferably, when there is no air pressure in the unlocking chamber, the disc spring assembly pushes the piston of the locking cylinder to move, and pushes the compression ring to move towards the large end of the elastic cone sleeve through the extension of the linkage rod, and the compression cone sleeve radially contracts to lock the piston rod; when compressed air is introduced into the unlocking chamber, the piston inside the locking cylinder compresses the disc spring assembly, controls the linkage rod to retract and drives the compression ring to move towards the small end of the elastic cone sleeve, and the cone sleeve radially opens to release the piston rod.

[0012] Preferably, the mechanical locking unit further includes a sealing dust cover, which is a corrugated tube or telescopic sleeve structure, covering the outside of the elastic cone sleeve and the extrusion ring, with its two ends fixed to the end cover of the drive cylinder and the extrusion ring, respectively.

[0013] Preferably, a throttle valve is provided in the air path between the third air outlet and the unlocking chamber of the locking cylinder to adjust the inflation speed of the unlocking chamber.

[0014] Preferably, the built-in pressure stability judgment logic of the electronic control unit is to confirm the unlocking is completed and allow the drive air circuit to be opened when the pressure of the second control port reaches a preset threshold and remains stable for a period of not less than 100ms.

[0015] This invention also discloses a pneumatic-mechanical linkage unloading control method for railway freight cars, including an opening control process and a closing control process; the opening control process includes, in sequence: S11. Door opening and unlocking steps: The electronic control unit controls the three-position five-way solenoid reversing valve to switch to the open position. Compressed air enters the unlocking chamber of the locking cylinder through the third air outlet. While pushing the mechanical unlocking, it sends a pressure feedback signal to the second control port of the dual-pressure linkage sequence valve. At this time, the drive air path is blocked by the dual-pressure linkage sequence valve. S12. Door opening drive steps: When the unlocking chamber pressure reaches the preset threshold, the dual-pressure linkage sequence valve is turned on, and compressed air enters the rodless chamber of the drive cylinder through the first air outlet. The piston rod extends and drives the bottom door to open. S13. Door opening and locking steps: After the bottom door reaches the target opening degree, the three-position five-way solenoid valve is de-energized and reset to the Y-type middle position. The drive cylinder and the unlocking chamber are depressurized at the same time. The disc spring group pushes the compression ring to compress the elastic cone sleeve radially and locks the piston rod to maintain the bottom door opening. The door closing control process includes the following steps: S21. Door closing and unlocking procedure: The electronic control unit controls the three-position five-way solenoid valve to switch to the closed position, and compressed air enters the unlocking chamber through the third air outlet to complete the mechanical unlocking. S22. Door closing drive steps: After the unlocking pressure reaches the standard, the dual-pressure linkage sequence valve is turned on, and compressed air enters the rod chamber of the drive cylinder through the second air outlet. The piston rod retracts and drives the bottom door to close. S23. Door closing and locking procedure: After the bottom door is completely closed, the three-position five-way solenoid valve is reset to the Y-type neutral position, and the system pressure relief is completed and mechanical locking is achieved.

[0016] Preferably, in the door opening and closing driving steps, the unlocking chamber pressure must remain stable for no less than 100ms after reaching the preset threshold before the unlocking is confirmed to be complete and the driving air path is opened.

[0017] Preferably, in the door opening and closing locking steps, when the three-position five-way solenoid valve is in the Y-type middle position, the first air outlet, the second air outlet, and the third air outlet are all connected to the exhaust port, and the two chambers of the drive cylinder and the unlocking chamber are emptied simultaneously.

[0018] Therefore, the present invention employs the above-mentioned air-motor linkage unloading control system and method for railway freight cars, which has the following technical effects: (1) The present invention simplifies the traditional nine or more independent valve components into a core configuration of one three-position five-way solenoid directional valve plus two dual-pressure linkage sequence valves. It adopts the internal air circuit of the valve body integrated block to replace the external pipe circuit, reducing leakage points and failure points, reducing manufacturing, installation and maintenance costs, and significantly improving the overall reliability of the system.

[0019] (2) This invention establishes a closed-loop interlocking mechanism of unlocking pressure and driving action through a dual-pressure linkage sequence valve. The unlocking chamber pressure reaching the target is a necessary prerequisite for the driving cylinder to move. From a hardware perspective, it ensures that the drive will not move if the unlocking is not in place, thus eliminating the risk of mechanism jamming and damage caused by forced driving when the locking is not completed. Compared with traditional open-loop delay control, the interlocking based on pressure feedback can adapt to changes in working conditions, and has higher safety and reliability.

[0020] (3) The present invention adopts a Y-type functional center position design. After locking, the drive cylinder and the unlocking chamber are completely depressurized. The load is borne by the static friction force of the elastic cone sleeve and the piston rod and the self-locking effect of the cone surface. It does not rely on air pressure to maintain the opening, and achieves long-term position maintenance with zero air consumption and zero current, fundamentally eliminating the opening drift problem caused by pneumatic internal leakage.

[0021] (4) The present invention can lock at any position of the piston rod throughout the entire stroke by means of the radial clamping structure of the elastic cone sleeve. The bottom door opening is continuously adjustable, realizing stepless control. It can match the unloading flow requirements of different particle sizes of goods such as coal and ore. Compared with the traditional discrete gear control, it greatly improves the unloading control accuracy.

[0022] (5) The present invention adopts a normally closed disc spring locking structure, combined with a conical force-enhancing design, which greatly reduces the difficulty of unlocking under load; at the same time, it is equipped with a fully sealed dust cover, which can effectively isolate dust and coal dust in the railway freight car transportation environment, avoid jamming and wear of mating surfaces, adapt to harsh working conditions, and extend the service life of the equipment.

[0023] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the overall architecture of a railway freight car bottom door air-motor linkage unloading control system according to the present invention; Figure 2 This is a schematic diagram of the pneumatic control unit in the pneumatic-motor linkage unloading control system for the bottom door of a railway freight car according to the present invention. Figure 3 This is a cross-sectional structural diagram of the dual-pressure linkage sequence valve in the non-conducting state of a railway freight car bottom door air-motor linkage unloading control system according to the present invention. Figure 4 This is a cross-sectional structural diagram of the dual-pressure linkage sequence valve in the on-state of a railway freight car bottom door air-motor linkage unloading control system according to the present invention. Figure 5 This is an overall structural diagram of the mechanical locking unit in the air-motor linkage unloading control system for the bottom door of a railway freight car according to the present invention; Figure 6 This is a three-dimensional structural diagram of the elastic cone sleeve in the air-motor linkage unloading control system for the bottom door of a railway freight car according to the present invention; Figure 7 This is a cross-sectional view of the elastic cone sleeve in the air-motor linkage unloading control system for the bottom door of a railway freight car according to the present invention; Figure 8 This is a schematic diagram of the piston rod locking state in a gas-motor linkage unloading control system for the bottom door of a railway freight car according to the present invention; Figure 9 This is a schematic diagram of the piston rod unlocking state in a gas-motor linkage unloading control system for the bottom door of a railway freight car according to the present invention; Figure 10 This is a working cycle block diagram of a railway freight car bottom door air-motor linkage unloading control system according to the present invention.

[0025] Figure Labels 1. Pneumatic control unit; 11. Valve body integrated block; 12. Three-position five-way solenoid directional valve; 13. First sequence valve; 14. Second sequence valve; 15. Valve core; 16. Return spring; 17. Throttle valve; 2. Mechanical locking unit; 21. Drive cylinder; 211. Piston rod; 22. Limiting guide sleeve; 221. Support rod; 23. Elastic cone sleeve; 231. Through groove; 232. Annular oil reservoir; 24. Compression ring; 241. Linkage rod; 25. Locking cylinder; 3. Sensing and control system; 4. Air inlet; 5. First air outlet; 6. Second air outlet; 7. Third air outlet; 8. Exhaust port; 9. First control port; 10. Second control port. Detailed Implementation

[0026] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0027] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0028] like Figure 1 As shown, a pneumatic-mechanical linkage unloading control system for the bottom door of a railway freight car mainly consists of three parts: a pneumatic control unit 1, a mechanical locking unit 2, and a sensing and control system 3. The pneumatic control unit 1 is connected to the mechanical locking unit 2 through a pneumatic circuit. The sensing and control system 3 collects system status signals and controls the action of the pneumatic control unit 1 to realize the pneumatic-mechanical linkage control of the bottom door opening, closing and locking.

[0029] like Figure 2 As shown, the pneumatic control unit 1 includes a valve body integrated block 11, a three-position five-way solenoid directional valve 12, and two dual-pressure linkage sequence valves, namely the first sequence valve 13 and the second sequence valve 14. The valve body integrated block 11 is made of integrated aluminum alloy material and has a pre-fabricated precision airflow channel inside. It has five air ports: an air inlet 4, a first air outlet 5, a second air outlet 6, a third air outlet 7, and an exhaust port 8. The air passage connections between each air port are all integrated inside the valve body, replacing the traditional external piping, effectively reducing leakage points, and making the structure more compact.

[0030] A three-position five-way solenoid directional valve 12 is mounted on the top surface of the valve body integrated block 11, and has three positions: left (open), right (closed), and center. The center position is Y-shaped: when the solenoid valve is de-energized and in the center position, the first outlet 5, second outlet 6, and third outlet 7 are all connected to the exhaust port 8, achieving simultaneous pressure relief in both the drive and unlocking air paths. A first sequence valve 13 is connected in series between the first outlet 5 and the rodless chamber of the drive cylinder 21, and a second sequence valve 14 is connected in series between the second outlet 6 and the rod chamber of the drive cylinder 21. The two sequence valves have identical structures and are both dual-pressure control type, equipped with a first control port 9 (internal control port) and a second control port 10 (external control port). Taking the first sequence valve 13 as an example, its first control port 9 is connected to the first outlet 5 to receive drive air pressure; its second control port 10 is connected to the third outlet 7 to receive pressure feedback signals from the unlocking chamber.

[0031] Combination Figure 3 and Figure 4 As shown, the sequence valve contains a valve core 15 and a return spring 16. Initially, the return spring 16 pushes the valve core 15 to the closed position, blocking the air path from the first control port 9 to the outlet. When the pressure at the second control port 10 rises to a preset threshold, the air pressure overcomes the elasticity of the return spring 16, pushing the valve core 15 to the open position, connecting the first control port 9 to the outlet and opening the drive air path. This structure physically ensures that the drive cylinder 21 can only be activated after the unlocking chamber pressure reaches the standard and the mechanical locking is fully released, achieving inherent safety through pressure interlocking. A throttle valve 17 is installed on the air path between the third outlet 7 and the unlocking chamber of the locking cylinder 25 to adjust the inflation speed of the unlocking chamber, preventing excessive inflation from causing unlocking shock and improving operational smoothness.

[0032] like Figure 5 As shown, the mechanical locking unit 2 adopts a coaxial series layout, consisting of a drive cylinder 21, a limiting guide sleeve 22, an elastic cone sleeve 23, a compression ring 24, and a locking cylinder 25 arranged sequentially along the axial direction. The drive cylinder 21 is a double-acting piston cylinder, and its piston rod 211 extends outward and is connected to the bottom door of the railway freight car via a linkage mechanism; when the piston rod 211 extends, it drives the bottom door to open, and when it retracts, it drives the bottom door to close. The limiting guide sleeve 22 is fixedly installed on the outer side of the front end cover of the drive cylinder 21 near the locking cylinder 25 by multiple circumferentially distributed support rods 221. A guide hole is opened in the center of the limiting guide sleeve 22, through which the piston rod 211 of the drive cylinder passes and slides in cooperation with the guide hole, providing precise axial guidance for the piston rod 211 and the locking mechanism, ensuring coaxiality and avoiding off-center loading and jamming.

[0033] The elastic cone sleeve 23 is fixedly fitted into the guide hole of the limiting guide sleeve 22 and sleeved on the outside of the piston rod 211. (Combined) Figure 6 and Figure 7 As shown, the elastic cone sleeve 23 is generally frustum-shaped, with an inner cone surface on the inner wall and an inner cone angle α of 15°. The larger end faces the driving cylinder 21, and the smaller end faces the locking cylinder 25. The elastic cone sleeve 23 has eight circumferentially distributed through grooves 231 along the axial direction. The through grooves 231 extend from one end of the cone sleeve to the other end, giving the cone sleeve the ability to deform radially: when subjected to radial compression, the cone sleeve contracts along the through grooves, the inner diameter decreases, and it grips the piston rod 211; when the compression is released, it returns to its original position due to its own elasticity, the inner diameter increases, and the piston rod 211 is released.

[0034] The inner wall of the elastic cone sleeve 23 also has multiple annular oil reservoirs 232, filled with molybdenum disulfide grease. These reservoirs continuously lubricate the mating surfaces of the cone sleeve and piston rod 211 during locking and unlocking, reducing the coefficient of friction, minimizing wear, and improving operational reliability and service life. The 15° inner cone angle design balances locking reliability and unlocking convenience: the cone angle is smaller than the friction self-locking angle, forming a cone-shaped self-locking surface, ensuring that it will not loosen due to load vibration after locking; at the same time, the angle is not too small to avoid excessive unlocking force leading to unlocking difficulties.

[0035] The compression ring 24 is sleeved outside the piston rod 211, located between the elastic cone sleeve 23 and the locking cylinder 25. The inner wall of the compression ring 24 is a conical surface that matches the shape of the elastic cone sleeve 23, and it can move axially along the piston rod 211. The compression ring 24 is fixedly connected to the internal piston of the locking cylinder 25 through multiple circumferentially distributed linkage rods 241. The linkage rods 241 seal through the end cap of the locking cylinder 25, transmitting the axial movement of the piston to the compression ring 24.

[0036] The locking cylinder 25 is coaxially arranged with the driving cylinder 21. Its internal cavity is divided into an unlocking chamber and a spring chamber by a piston. A disc spring assembly is installed in the spring chamber. The disc spring assembly is a normally closed structure, always applying a spring force to the piston towards the large end of the elastic cone sleeve. When there is no air pressure in the unlocking chamber, the disc spring assembly pushes the piston towards the driving cylinder 21, which in turn drives the compression ring 24 towards the large end of the elastic cone sleeve 23 via the linkage rod 241. The conical surface of the inner wall of the compression ring 24 compresses the elastic cone sleeve 23, causing the cone sleeve to contract radially and grip the piston rod 211, thus achieving mechanical locking. Figure 8 As shown. When compressed air is introduced into the unlocking chamber, the air pressure pushes the piston to compress the disc spring assembly, which in turn drives the compression ring 24 to move away from the drive cylinder 21 via the linkage rod 241, until the compression ring 24 exits the cone sleeve 23, releasing the radial compression on the cone sleeve 23; the elastic cone sleeve 23 opens radially under its own elasticity, releasing the piston rod 211, completing the unlocking process, as shown. Figure 9 As shown.

[0037] The mechanical locking unit 2 also includes a sealed dust cover, which adopts a corrugated pipe structure or a telescopic sleeve structure, and is entirely covered outside the elastic cone sleeve 23, the compression ring 24, and the limiting guide sleeve 22. One end of the sealed dust cover is fixed to the front end cover of the drive cylinder 21, and the other end is fixed to the end face of the compression ring 24. It can extend and retract synchronously with the axial movement of the compression ring 24, completely sealing the locking mating area, effectively isolating dust and coal dust in the railway freight car transportation environment from intrusion, avoiding jamming and wear of the mating surfaces, and improving the reliability of the equipment under harsh working conditions.

[0038] like Figure 1As shown, the sensing and control system 3 includes a pressure sensor, a displacement sensor, and an electronic control unit. The pressure sensor is installed on the air path of the third air outlet 7 to monitor the pressure value of the unlocking chamber in real time and transmit the pressure signal to the electronic control unit as the basis for determining whether unlocking is complete. The displacement sensor can be installed on the cylinder body of the drive cylinder 21 to monitor the stroke of the piston rod 211; it can also be installed at the bottom door pivot to directly monitor the opening angle of the bottom door and transmit the opening signal to the electronic control unit to achieve closed-loop control of the opening.

[0039] The electronic control unit (ECU) is the core of the system's control, with built-in control logic. It receives pressure and displacement signals and outputs control signals to energize and de-energize the electromagnet of the three-position five-way solenoid directional valve 12, thereby achieving automatic system control. The ECU has built-in pressure stability judgment logic: when the unlocking chamber pressure reaches a preset threshold, it must remain stable for at least 100ms before unlocking is confirmed and the drive air path is allowed to open. This effectively avoids frequent operation of the sequence valve caused by pressure fluctuations due to vehicle vibration, thus improving system stability.

[0040] like Figure 10 As shown, the present invention also includes a gas-motor linkage unloading control method for railway freight car bottom doors, comprising a door opening control process and a door closing control process, the specific steps of which are as follows: Door opening control procedure: S11. Door opening and unlocking stage: After receiving the door opening command, the electronic control unit outputs a control signal to energize the left-position electromagnet of the three-position five-way solenoid directional valve 12, and the directional valve switches to the left position (open position). Compressed air enters the valve body integrated block 11 from the air inlet 4 and is divided into two paths: the first path reaches the first control port 9 of the first sequence valve 13 through the P→A passage, but at this time the first sequence valve 13 is in the closed state, the air is blocked, and the drive cylinder 21 does not move; the second path is output from the third air outlet 7 through the P→C passage and is divided into two branches: one branch enters the unlocking chamber of the locking cylinder 25 through the throttle valve 17, pushes the piston to slowly compress the disc spring assembly, and drives the compression ring 24 to move away from the drive cylinder 21 through the linkage rod 241, and the elastic cone sleeve 23 gradually opens radially, and mechanical unlocking begins; the other branch enters the second control port 10 of the first sequence valve 13 to establish a pressure feedback signal.

[0041] S12. Door Opening Drive Stage: As the pressure inside the unlocking chamber continues to rise, the pressure at the second control port 10 of the first sequence valve 13 also increases synchronously. When the pressure reaches the preset threshold P_set, and the pressure sensor detects that the pressure stability lasts for ≥100ms, mechanical unlocking is confirmed to be complete. At this time, the valve core of the first sequence valve 13 moves to the open position under the action of air pressure, overcoming the force of the return spring 16, and the air path from the first control port 9 to the rodless chamber of the drive cylinder is opened. Compressed air enters the rodless chamber of the drive cylinder 21 through the first sequence valve 13 and the first outlet 5, while the rod chamber of the drive cylinder is connected to the exhaust port 8 through the second outlet 6 and the right position of the reversing valve to exhaust air. The piston rod 211 extends smoothly, driving the bottom door to open through the linkage mechanism. The displacement sensor monitors the piston rod stroke, i.e., the bottom door opening degree, in real time. When the target opening degree is reached, the electronic control unit triggers the locking action.

[0042] S13. Door opening and locking stage: After the bottom door reaches the target opening degree, the electronic control unit controls the electromagnet of the three-position five-way solenoid valve 12 to de-energize, and the valve is reset to the middle position (Y-type function) under the action of the return spring 16. At this time, the first air outlet 5 and the second air outlet 6 are connected to the exhaust port 8, and the rodless chamber and the rod chamber of the drive cylinder 21 are depressurized at the same time, and the piston rod 211 is in a floating state; the third air outlet 7 is connected to the exhaust port 8, and the unlocking chamber of the locking cylinder 25 is depressurized quickly; the disc spring group releases the elastic force, pushes the piston to move towards the drive cylinder 21, and drives the compression ring 24 to move towards the large end of the elastic cone sleeve 23 through the linkage rod 241; the inner wall cone surface of the compression ring 24 compresses the cone sleeve, causing the elastic cone sleeve 23 to contract radially, and the inner wall tightly hugs the locking section of the piston rod 211, relying on static friction and the cone surface self-locking effect to reliably lock the bottom door at the target opening degree. After locking, the system is in a state of zero air consumption and zero power consumption, and the bottom door opening can remain stable for a long time, completely eliminating the slow crawling problem of pneumatic positioning.

[0043] Door closing control procedure: S21. Door Closing and Unlocking Stage: After receiving the door closing command, the electronic control unit outputs a control signal to energize the right-side solenoid of the three-position five-way solenoid directional valve 12, switching the directional valve to the right position (closed position). Compressed air enters the valve body from the inlet 4 and is divided into two paths: the first path reaches the first control port 9 of the second sequence valve 14 via the P→B ​​passage, the air path is blocked, and the drive cylinder 21 does not move; the second path is output from the third outlet 7 via the P→C passage, one path enters the unlocking chamber to drive the mechanical unlocking, and the other path enters the second control port 10 of the second sequence valve 14 to establish pressure feedback.

[0044] S22. Door Closing Drive Phase: When the unlocking chamber pressure rises to a preset threshold and stabilizes for ≥100ms, the second sequence valve 14 is activated, and compressed air enters the rod chamber of the drive cylinder 21 through the second outlet 6. The rodless chamber exhausts air through the first outlet 5 and the exhaust port 8. The piston rod 211 retracts smoothly, gradually closing the bottom door. The displacement sensor monitors the bottom door position, and triggers the locking action when the bottom door is fully closed.

[0045] S23. Door closing and locking stage: After the bottom door is fully closed, the three-position five-way solenoid valve 12 is de-energized and resets to the Y-type neutral position, and the two chambers of the drive cylinder and the unlocking chamber are depressurized simultaneously. The disc spring assembly pushes the compression ring 24 again to compress the elastic cone sleeve 23, locking the piston rod 211, and the bottom door is reliably locked in the closed position.

[0046] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A pneumatic-motor linkage unloading control system for railway freight cars, characterized in that: The system includes a pneumatic control unit, a mechanical locking unit, and a sensing and control system. The pneumatic control unit comprises a valve body integrated block, a three-position five-way solenoid directional valve, and two dual-pressure linkage sequence valves. The three-position five-way solenoid directional valve is mounted on the valve body integrated block and has an open position, a closed position, and a Y-shaped functional neutral position. The valve body integrated block has an air inlet, a first air outlet, a second air outlet, a third air outlet, and an exhaust port. The two dual-pressure linkage sequence valves are connected in series between the first air outlet and the rodless chamber of the drive cylinder, and between the second air outlet and the rod chamber of the drive cylinder, respectively. Each dual-pressure linkage sequence valve has a first control port and a second control port. The mechanical locking unit includes coaxially arranged... The system comprises a drive cylinder, an elastic cone sleeve, a compression ring, and a locking cylinder. The piston rod of the drive cylinder is drivenly connected to the bottom door. The elastic cone sleeve and the compression ring are both sleeved on the outer surface of the piston rod of the drive cylinder. The locking cylinder has a disc spring assembly and an unlocking chamber. The internal piston of the locking cylinder is drivenly connected to the compression ring. The third air outlet is simultaneously connected to the unlocking chamber of the locking cylinder and the second control port of two dual-pressure linkage sequence valves. The sensing and control system includes a pressure sensor, a displacement sensor, and an electronic control unit. The pressure sensor monitors the pressure in the unlocking chamber, the displacement sensor monitors the opening degree of the bottom door, and the electronic control unit controls the position switching of the three-position five-way solenoid directional valve according to the sensor signals.

2. The railway freight car bottom door pneumatic-motor linkage unloading control system according to claim 1, characterized in that: The locking cylinder and the piston rod end of the driving cylinder are coaxially and fixedly connected; the mechanical locking unit also includes a limiting guide sleeve, which is fixedly set on the outer surface of the driving cylinder near the locking cylinder by a support rod; the piston rod of the driving cylinder passes through a guide hole opened at the center of the limiting guide sleeve and slides with the guide hole, and the elastic cone sleeve is fixedly set inside the guide hole; the extrusion ring slides with the piston rod of the driving cylinder and is connected to the piston inside the locking cylinder through a linkage rod; one end of the linkage rod is fixedly connected to the surface of the extrusion ring away from the elastic cone sleeve, and the other end seals and passes through the locking cylinder and is fixedly connected to the piston inside the locking cylinder.

3. The railway freight car bottom door pneumatic-motor linkage unloading control system according to claim 2, characterized in that: The inner wall of the elastic cone sleeve is frustoconical with an inner cone angle of 15° and the larger end faces the drive cylinder side; the elastic cone sleeve has several through grooves evenly distributed along the axial direction and an annular oil reservoir is provided on the inner wall.

4. The railway freight car bottom door pneumatic-motor linkage unloading control system according to claim 3, characterized in that: When there is no air pressure in the unlocking chamber, the disc spring assembly pushes the piston of the locking cylinder to move, and through the extension of the linkage rod, pushes the compression ring to move towards the large end of the elastic cone sleeve, and the compression cone sleeve contracts radially to lock the piston rod; when compressed air is introduced into the unlocking chamber, the piston inside the locking cylinder compresses the disc spring assembly, controls the linkage rod to retract and drives the compression ring to move away from the driving cylinder until it exits the elastic cone sleeve, and the cone sleeve opens radially to release the piston rod.

5. A railway freight car bottom door pneumatic-motor linkage unloading control system according to claim 4, characterized in that: The mechanical locking unit also includes a sealing dust cover, which is a corrugated tube or telescopic sleeve structure, covering the outside of the elastic cone sleeve and the extrusion ring, with its two ends fixed to the end cover of the drive cylinder and the extrusion ring, respectively.

6. The railway freight car bottom door pneumatic-motor linkage unloading control system according to claim 5, characterized in that: A throttle valve is installed in the air path between the third air outlet and the unlocking chamber of the locking cylinder to adjust the inflation speed of the unlocking chamber.

7. A railway freight car bottom door pneumatic-motor linkage unloading control system according to claim 6, characterized in that: The built-in pressure stability judgment logic of the electronic control unit is to confirm the unlocking is completed and allow the drive air circuit to be opened when the pressure of the second control port reaches the preset threshold and remains stable for a period of not less than 100ms.

8. A method for controlling the unloading of railway freight cars using a pneumatic-motor linkage, implemented based on the system described in claim 7, characterized in that... This includes a door opening control process and a door closing control process. The door opening control process includes, in sequence: S11. Door opening and unlocking steps: The electronic control unit controls the three-position five-way solenoid reversing valve to switch to the open position. Compressed air enters the unlocking chamber of the locking cylinder through the third air outlet. While pushing the mechanical unlocking, it sends a pressure feedback signal to the second control port of the dual-pressure linkage sequence valve. At this time, the drive air path is blocked by the dual-pressure linkage sequence valve. S12. Door opening drive steps: When the unlocking chamber pressure reaches the preset threshold, the dual-pressure linkage sequence valve is turned on, and compressed air enters the rodless chamber of the drive cylinder through the first air outlet. The piston rod extends and drives the bottom door to open. S13. Door opening and locking steps: After the bottom door reaches the target opening degree, the three-position five-way solenoid valve is de-energized and reset to the Y-type middle position. The drive cylinder and the unlocking chamber are depressurized at the same time. The disc spring group pushes the compression ring to compress the elastic cone sleeve radially and locks the piston rod to maintain the bottom door opening. The door closing control process includes the following steps: S21. Door closing and unlocking procedure: The electronic control unit controls the three-position five-way solenoid valve to switch to the closed position, and compressed air enters the unlocking chamber through the third air outlet to complete the mechanical unlocking. S22. Door closing drive steps: After the unlocking pressure reaches the standard, the dual-pressure linkage sequence valve is turned on, and compressed air enters the rod chamber of the drive cylinder through the second air outlet. The piston rod retracts and drives the bottom door to close. S23. Door closing and locking procedure: After the bottom door is completely closed, the three-position five-way solenoid valve is reset to the Y-type neutral position, and the system pressure relief is completed and mechanical locking is achieved.

9. A method for controlling the unloading of railway freight cars using a pneumatic-motor linkage according to claim 8, characterized in that: In the door opening and closing steps, the unlocking chamber pressure must remain stable for at least 100ms after reaching the preset threshold before unlocking is confirmed and the driving air path is opened.

10. The method for controlling the unloading of railway freight cars by pneumatic-motor linkage according to claim 9, characterized in that: In the door opening and closing locking steps, when the three-position five-way solenoid valve is in the Y-type middle position, the first air outlet, the second air outlet, and the third air outlet are all connected to the exhaust port, and the two chambers of the drive cylinder and the unlocking chamber are emptied simultaneously.

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