Magnetic suspension train undercarriage control system based on array type combination valve

Abstract

The invention provides a magnetically levitated train undercarriage control system based on array type combination valves, and belongs to the technical field of rail transit vehicle brake control. The system is applied to a maglev train in a high-intensity magnetic field environment and comprises an oil source device; the at least one undercarriage control device is mounted on a suspension frame of the maglev train, and each undercarriage control device comprises at least one undercarriage actuating cylinder used for driving the extension or retraction of the undercarriage; the array type combination valve is connected between the oil source device and the undercarriage actuating cylinder, the array type combination valve is composed of a plurality of switch type electromagnetic valves, and pressure oil is controlled to enter or be discharged out of different working cavities of the undercarriage actuating cylinder by controlling the combination of the power-on state and the power-off state of the switch type electromagnetic valves, so that extension or retraction of the undercarriage is achieved. The invention aims to solve the technical problem that the maintenance period is short due to the fact that an existing hydraulic control system for the undercarriage of the magnetically levitated train is poor in reliability and prone to inner leakage and clamping stagnation in a high-intensity magnetic field environment.

Description

Technical Field

[0001] This invention belongs to the field of braking control technology for rail transit vehicles, specifically relating to a landing gear control system for a magnetic levitation train based on an array-type combined valve. Background Technology

[0002] Maglev trains are a new type of rail transit that offers advantages over conventional rail vehicles, including higher speed, greater comfort, and greater load capacity. When a maglev train is running at high speed, it does not directly contact the track but levitates in the air using the magnetic force generated between the train and the track. To ensure stable operation and support during low-speed and braking phases, maglev vehicles are equipped with landing gear systems.

[0003] Currently, high-speed maglev trains are not yet in commercial operation and are still in the technological research stage. In existing technologies, the landing gear control system of maglev trains mainly uses a hydraulic control system. This leverages the advantages of hydraulic systems—high power density, high control precision, and fast response speed—to achieve precise control of the maglev train's landing gear and ensure stable vehicle operation.

[0004] In existing maglev train landing gear control schemes, proportional directional valves are primarily used to control the extension and retraction of the landing gear. However, proportional directional valves are susceptible to impurities in the hydraulic fluid, which can cause blockages and lead to malfunction. Furthermore, the proportional directional valve requires complex signal amplification circuits and magnetic shielding to withstand strong magnetic fields. Additionally, the proportional directional valve uses the movement of a cylindrical spool valve to achieve fluid reversal; the presence of spool valve clearance results in significant internal leakage, necessitating continuous replenishment of the control system to ensure sufficient fluid in the accumulator for the required number of cycles. These factors contribute to the complexity, large size and weight, and low reliability of existing hydraulic systems.

[0005] Therefore, it is urgent to find a new technical solution to solve the above problems. Summary of the Invention

[0006] The technical problem to be solved: To overcome the shortcomings of existing technologies, this invention provides a maglev train landing gear control system that is suitable for strong magnetic environments, has high reliability, and a long maintenance-free cycle. It uses an "array-type combination valve" composed of multiple on / off solenoid valves (normally open / normally closed) to replace the traditional proportional directional valve, thereby controlling the landing gear actuators and hydraulic locks. This invention aims to solve the technical problems of poor reliability, susceptibility to internal leakage and jamming in existing maglev train landing gear hydraulic control systems under strong magnetic field environments, resulting in short maintenance cycles.

[0007] The technical solution of this invention is: a magnetic levitation train landing gear control system based on an array-type combined valve, applied to magnetic levitation trains in strong magnetic field environments, comprising: An oil supply unit is used to store and supply pressurized oil to the system; At least one landing gear control device is mounted on the suspension frame of the maglev train, and each of the landing gear control devices includes: At least one landing gear actuator for driving the extension or retraction of the landing gear; An array-type combination valve is connected between the oil source device and the landing gear actuator cylinder. The array-type combination valve consists of multiple on / off solenoid valves. By controlling the combination of the energized and de-energized states of the multiple on / off solenoid valves, the pressure oil is controlled to enter or exit different working chambers of the landing gear actuator cylinder to realize the extension or retraction of the landing gear. The oil circuit connection of the array-type combination valve is configured to have a fail-safe function. When the system loses power, the array-type combination valve automatically connects the working chamber of the landing gear actuator cylinder with the return oil circuit so that the landing gear can be lowered by gravity in an emergency.

[0008] A further technical solution of the present invention is: the array-type combination valve includes a landing gear control combination valve for controlling a single landing gear actuator; The landing gear control combination valve includes a first normally closed solenoid valve, a second normally closed solenoid valve, a first normally open solenoid valve, and a second normally open solenoid valve. The landing gear control combination valve is provided with a first oil port, a second oil port, a third oil port and a fourth oil port. The first oil port is connected to the oil supply line of the oil source device, the second oil port is connected to the oil return line of the oil source device, the third oil port is connected to the rodless chamber of the landing gear actuator, and the fourth oil port is connected to the rod chamber of the landing gear actuator. The first normally closed solenoid valve is connected between the first oil port and the fourth oil port, the second normally closed solenoid valve is connected between the first oil port and the third oil port, the first normally open solenoid valve is connected between the second oil port and the third oil port, and the second normally open solenoid valve is connected between the second oil port and the fourth oil port. A further technical solution of the present invention is that each of the landing gear control devices further includes: At least one upper lock actuator is used to lock or unlock the landing gear in the retracted state; At least one lower locking actuator is used to lock or unlock the landing gear in the extended position; The hydraulic lock control combination valve consists of multiple on / off solenoid valves connected between the oil source device and the upper and lower lock actuators, and is used to control the unlocking of the upper and lower lock actuators. A pressure reducing valve is installed on the oil supply line between the oil source device and the hydraulic lock control combination valve. It is used to reduce the oil supply pressure to the preset pressure value required by the lock actuator.

[0009] A further technical solution of the present invention is: the hydraulic lock control combination valve includes a third normally closed solenoid valve and a fourth normally closed solenoid valve; The hydraulic lock control combination valve is provided with a fifth oil port, a sixth oil port and a seventh oil port. The fifth oil port is connected to the oil supply circuit of the oil source device via a pressure reducing valve. The sixth oil port is connected to the return oil circuit of the oil source device. The seventh oil port is connected to the control chamber of the upper lock actuator or the lower lock actuator. The third normally closed solenoid valve is connected between the fifth and seventh oil ports, and the fourth normally closed solenoid valve is connected between the sixth and seventh oil ports.

[0010] A further technical solution of the present invention is: each of the landing gear control devices further includes a balance valve, which is disposed between the rodless chamber oil passage and the rod chamber oil passage of the landing gear actuator cylinder. When the array-type combination valve is switched on and off, the balance valve is used to throttle the return oil of the actuator cylinder by means of hydraulic control, so as to resist the pressure shock caused by sudden load change and ensure the smooth operation of the landing gear. A further technical solution of the present invention is that each landing gear control device further includes multiple pressure sensors, which are respectively installed in the rodless chamber oil circuit, the rod chamber oil circuit, and the control chamber oil circuit of the landing gear actuator cylinder, for real-time monitoring of the pressure of each oil circuit.

[0011] A further technical solution of the present invention is: the control system includes multiple landing gear control devices, which are respectively installed on both sides of the same suspension frame of the maglev train, for independently controlling the landing gear on both sides to achieve the balance of the vehicle load and the symmetry of the layout. A further technical solution of the present invention is: the oil source device includes: The fuel tank stores the control fluid required for the landing gear system. An electric motor and a hydraulic pump driven by the electric motor are used to draw oil from the oil tank; An accumulator, located at the outlet of the hydraulic pump, is used to store pressurized oil and provide a pressurized oil source for the landing gear control system. A check valve is installed between the hydraulic pump and the accumulator to prevent the oil in the accumulator from flowing back. A method for controlling the landing gear of a maglev train based on the system includes a landing gear extension control step: Step 1: After receiving the landing gear extension command, the normally closed solenoid valve in the hydraulic lock control combination valve is energized and opened, so that the pressure oil after being reduced by the pressure reducing valve enters the rodless chamber of the corresponding upper lock actuator cylinder, driving the upper lock to unlock. Step 2: The normally closed solenoid valve connected to the rodless chamber of the landing gear actuator cylinder in the control array combination valve is energized and opened, and at the same time the normally open solenoid valve connected to the rodless chamber is energized and closed, so that the pressurized oil enters the rodless chamber of the landing gear actuator cylinder, and the oil in the rod chamber returns through the array combination valve, driving the landing gear to extend. Step 3: After the landing gear is extended to the position, all solenoid valves in the control array combination valve are de-energized, which connects the two chambers of the landing gear actuator cylinder to the return oil circuit. At the same time, the normally closed solenoid valve in the control hydraulic lock combination valve is energized and opened, which allows the oil in the rodless chamber of the lock actuator cylinder to return. The lock actuator cylinder retracts under the action of the return spring, locking the landing gear in the extended position.

[0012] A landing gear control method for a maglev train based on the system includes a landing gear retraction control step: Step 1: After receiving the landing gear retraction command, the normally closed solenoid valve in the hydraulic lock control combination valve is energized and opened, so that the pressure oil after being reduced by the pressure reducing valve enters the rodless chamber of the corresponding lower lock actuator cylinder, driving the lower lock to unlock. Step 2: The normally closed solenoid valve connected to the rod chamber of the landing gear actuator cylinder in the array-type combination valve is energized and opened, while the normally open solenoid valve connected to the rod chamber is energized and closed, so that the pressurized oil enters the rod chamber of the landing gear actuator cylinder, and the oil in the rodless chamber returns through the array-type combination valve, driving the landing gear to retract. Step 3: After the landing gear is retracted to the position, all solenoid valves in the control array combination valve are de-energized, connecting the two chambers of the landing gear actuator cylinder to the return oil circuit. At the same time, the normally closed solenoid valve in the control hydraulic lock combination valve is energized and opened, allowing the oil in the rodless chamber of the lock actuator cylinder to return. The lock actuator cylinder retracts under the action of the return spring, locking the landing gear in the retracted position.

[0013] Beneficial effects The beneficial effects of this invention are as follows: This invention provides a magnetic levitation train landing gear control system based on an array-type combined valve. The array-type combined valve controls the extension and retraction of the landing gear actuator cylinder, as well as the unlocking of the landing gear upper / lower position locks, avoiding the risk of valve jamming present in existing technologies and improving system reliability. Furthermore, the ball valve-type switching valve has lower internal leakage than the spool valves in existing technologies, reducing the number of times the hydraulic pump needs to be activated in the system. The technical solution adopted in this invention avoids the use of complex signal amplification circuits, reducing system complexity and improving system reliability in strong magnetic environments. Specific effects are analyzed as follows: 1. This invention abandons the proportional directional valve, which is susceptible to electromagnetic interference and requires complex amplification circuits, and instead adopts an array-type combined valve composed of simple on / off solenoid valves. The control signal of the on / off valve is only a digital signal of on / off switching, without the need for analog amplification. Therefore, it is naturally immune to the strong magnetic field environment under the maglev train, fundamentally eliminating the risk of control failure caused by electromagnetic interference. At the same time, the on / off valve core (such as a ball valve) is not sensitive to contaminants in the oil, completely eliminating the valve core jamming failure caused by tiny particles in traditional slide valves, greatly improving the operational reliability of the landing gear control system.

[0014] 2. Existing proportional directional valves employ a spool valve structure, and the clearance between the valve core and valve body inevitably leads to continuous internal leakage. To maintain accumulator pressure, the hydraulic pump needs to be frequently started to replenish oil, increasing energy consumption and component wear. The array-type combined valve used in this invention has a ball valve structure with a sealed contact, theoretically achieving zero leakage. This significantly reduces the system's internal leakage, enabling the accumulator to maintain pressure for a longer period, and significantly reducing the start-stop frequency of the hydraulic pump. This achieves energy savings and extends the service life of the hydraulic pump and motor, meeting the stringent requirements of rail transit equipment for long lifespan and maintenance-free operation.

[0015] 3. The array-type combination valve of the present invention, through a specific combination (such as a configuration of two normally open valves and two normally closed valves) and connection to the oil circuit, possesses a fail-safe function. When the system unexpectedly loses power (such as a power failure or emergency power outage), all solenoid valves return to their initial state, and the normally open valves automatically conduct the return oil circuit, so that both chambers of the landing gear actuator cylinder are simultaneously connected to the oil tank. At this time, the landing gear can automatically and reliably lower under its own weight, ensuring that the train can support the car body under any circumstances, avoiding the safety hazard of the landing gear failing to lower due to hydraulic system jamming or control failure, and significantly improving the overall safety of train operation.

[0016] 4. Although an on / off control is employed, this invention, through its collaborative design with a balance valve, hydraulically controls the return oil flow during landing gear retraction and extension, effectively mitigating pressure surges caused by sudden load changes. This ensures the smoothness of landing gear movement and compensates for the limitations of on / off valve control in terms of adjustment precision compared to proportional valves. Simultaneously, the extensive array of pressure sensors throughout the system monitors the pressure in both chambers of the actuator and the control chamber of the lock actuator in real time, providing data support for closed-loop control, fault diagnosis, and status monitoring, further enhancing the reliability and intelligence of the control. Attached Figure Description

[0017] Figure 1 This is a hydraulic schematic diagram of the array-type combined valve landing gear control system for a magnetic levitation train. Figure 2 This is the hydraulic schematic diagram of the landing gear control combination valve; Figure 3This is the hydraulic schematic diagram of the hydraulic lock control combination valve; Explanation of reference numerals in the attached drawings: 1000. Oil supply device; 2000. Landing gear control device; 3000. Landing gear control unit; 1001. Oil tank; 1002. Motor; 1003. Hydraulic pump; 1004. Relief valve; 1005. Check valve; 1006. Pressure sensor; 1007. Accumulator; 1008. Air filter; 1009. Level gauge.

[0018] 2100 / 2200. Landing gear control combination valve; 2001. Pressure reducing valve; 2400 / 2300. Hydraulic lock control combination valve; 2002 / 2003. Balance valve; 2004 / 2005 / 2006 / 2007 / 2008 / 2009. Pressure sensor; 2010 / 2011. Landing gear actuator; 2012 / 2013. Landing gear upper lock actuator; 2014 / 2015. Landing gear lower lock actuator; 2101. First normally closed solenoid valve; 2102. Second normally closed solenoid valve; 2103. First normally open solenoid valve; 2104. Second normally open solenoid valve; 2401. Third normally closed solenoid valve; 2402. Fourth normally closed solenoid valve.

[0019] 3100 / 3200. Landing gear control combination valve; 3001. Pressure reducing valve; 3400 / 3300. Hydraulic lock control combination valve; 3002 / 3003. Balance valve; 3004 / 3005 / 3006 / 3007 / 3008 / 3009. Pressure sensor; 3010 / 3011. Landing gear actuator; 3012 / 3013. Landing gear upper lock actuator; 3014 / 3015. Landing gear lower lock actuator. Detailed Implementation The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the invention, and should not be construed as limiting the invention.

[0020] Currently, high-speed maglev trains are still in the technical research and testing phase. Existing landing gear control schemes primarily draw on mature hydraulic control technology from aircraft landing gear, using proportional directional valves to precisely adjust the flow and direction of hydraulic oil entering the actuators, thereby achieving smooth extension and retraction of the landing gear. This approach leverages the advantages of high power density and fast response in hydraulic systems. However, directly transplanting aviation-grade hydraulic control technology into the maglev train environment faces the following inherent technical challenges and application limitations: The unique operating environment poses reliability risks: the strong magnetic field beneath the maglev train presents a serious threat to the proportional directional valves, which rely on precise analog signals. The complex signal amplification circuitry required for the proportional valves is highly susceptible to electromagnetic interference, leading to control inaccuracies. Furthermore, to ensure the valve core functions properly, a heavy magnetic shielding cover is necessary, increasing the system's weight and complexity.

[0021] The contradiction between high reliability requirements and component physical characteristics: Rail transit equipment has extremely high standards for system maintenance-free cycles and reliability. Existing solutions mostly use proportional directional valves with a spool valve structure, where a micrometer-level clearance exists between the valve core and the valve body. On the one hand, this clearance makes the valve core extremely sensitive to oil contamination, making it prone to jamming; on the other hand, the clearance leads to unavoidable internal leakage. To compensate for this internal leakage, the hydraulic pump needs to be frequently started to pressurize the system, which not only increases energy consumption but also accelerates component wear, making it difficult to meet the long-life, high-reliability requirements of the rail transit field.

[0022] System complexity and maintainability constraints: To meet functions such as sequential control and emergency lowering of the landing gear, existing technologies often require the addition of multiple hydraulic components, such as hydraulic locks, sequence valves, and throttle valves, on top of the proportional valve, connected through complex piping. This not only makes the system bulky and heavy but also increases manufacturing and maintenance costs, contradicting the design requirements of lightweight trains and high maintainability.

[0023] To address the aforementioned problems, this invention proposes a magnetic levitation train landing gear control system based on an array-type combined valve, applicable to magnetic levitation trains operating in strong magnetic field environments, comprising: An oil supply unit is used to store and supply pressurized oil to the system; At least one landing gear control device is mounted on the suspension frame of the maglev train, and each of the landing gear control devices includes: At least one landing gear actuator for driving the extension or retraction of the landing gear; An array-type combination valve is connected between the oil source device and the landing gear actuator cylinder. The array-type combination valve consists of multiple on / off solenoid valves. By controlling the combination of the energized and de-energized states of the multiple on / off solenoid valves, the pressure oil is controlled to enter or exit different working chambers of the landing gear actuator cylinder to realize the extension or retraction of the landing gear. The oil circuit connection of the array-type combination valve is configured to have a fail-safe function. When the system loses power, the array-type combination valve automatically connects the working chamber of the landing gear actuator cylinder with the return oil circuit so that the landing gear can be lowered by gravity in an emergency.

[0024] The present invention also proposes a landing gear control method for a magnetic levitation train based on the aforementioned system, including a landing gear extension control step: Step 1: After receiving the landing gear extension command, the normally closed solenoid valve in the hydraulic lock control combination valve is energized and opened, so that the pressure oil after being reduced by the pressure reducing valve enters the rodless chamber of the corresponding upper lock actuator cylinder, driving the upper lock to unlock. Step 2: The normally closed solenoid valve connected to the rodless chamber of the landing gear actuator cylinder in the control array combination valve is energized and opened, and at the same time the normally open solenoid valve connected to the rodless chamber is energized and closed, so that the pressurized oil enters the rodless chamber of the landing gear actuator cylinder, and the oil in the rod chamber returns through the array combination valve, driving the landing gear to extend. Step 3: After the landing gear is extended to the position, all solenoid valves in the control array combination valve are de-energized, which connects the two chambers of the landing gear actuator cylinder to the return oil circuit. At the same time, the normally closed solenoid valve in the control hydraulic lock combination valve is energized and opened, which allows the oil in the rodless chamber of the lock actuator cylinder to return. The lock actuator cylinder retracts under the action of the return spring, locking the landing gear in the extended position.

[0025] The present invention also proposes a landing gear control method for a magnetic levitation train based on the aforementioned system, including a landing gear retraction control step: Step 1: After receiving the landing gear retraction command, the normally closed solenoid valve in the hydraulic lock control combination valve is energized and opened, so that the pressure oil after being reduced by the pressure reducing valve enters the rodless chamber of the corresponding lower lock actuator cylinder, driving the lower lock to unlock. Step 2: The normally closed solenoid valve connected to the rod chamber of the landing gear actuator cylinder in the array-type combination valve is energized and opened, while the normally open solenoid valve connected to the rod chamber is energized and closed, so that the pressurized oil enters the rod chamber of the landing gear actuator cylinder, and the oil in the rodless chamber returns through the array-type combination valve, driving the landing gear to retract. Step 3: After the landing gear is retracted to the position, all solenoid valves in the control array combination valve are de-energized, connecting the two chambers of the landing gear actuator cylinder to the return oil circuit. At the same time, the normally closed solenoid valve in the control hydraulic lock combination valve is energized and opened, allowing the oil in the rodless chamber of the lock actuator cylinder to return. The lock actuator cylinder retracts under the action of the return spring, locking the landing gear in the retracted position.

[0026] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0027] Example 1: System Overall Structure Reference Figure 1 This embodiment provides a magnetic levitation train landing gear control system based on an array-type combined valve, including an oil source device 1000, a first landing gear control device 2000, and a second landing gear control device 3000.

[0028] In maglev trains, each suspension frame typically has four landing gears. This embodiment can control the four landing gear actuators on one suspension frame. Specifically, the first landing gear control device 2000 and the second landing gear control device 3000 integrate and encapsulate their hydraulic components, symmetrically mounted on both sides of the suspension frame to facilitate the counterweight balance of the onboard equipment layout. Each landing gear control device controls two landing gear actuators and the locking of the corresponding two upper landing gear locks and two lower landing gear locks.

[0029] I. Oil Source Equipment The oil source device 1000 is used to store pressurized oil and provide a stable pressurized oil source for the entire control system. Its specific structure includes: The oil tank 1001, made of stainless steel, is used to store the hydraulic fluid required for the landing gear system control, and has a volume of 120L. The oil tank 1001 is equipped with a level gauge 1009 and an air filter 1008. The level gauge 1009 indicates the oil level in the tank, facilitating daily inspection and maintenance; the air filter 1008 balances the air pressure inside the tank and filters impurities from the air entering the tank.

[0030] The motor 1002 and the hydraulic pump 1003 are connected. The output shaft of the motor 1002 is connected to the hydraulic pump 1003. The hydraulic pump 1003 is integrated with the oil tank 1001. The motor 1002 drives the hydraulic pump 1003 to draw oil from the oil tank 1001.

[0031] The relief valve 1004 is installed in the outlet pipeline of the hydraulic pump 1003 to regulate and limit the output pressure of the hydraulic pump 1003 and prevent the system pressure from being too high.

[0032] A one-way valve 1005 is installed on the pipeline between the hydraulic pump 1003 and the accumulator 1007 to prevent the high-pressure oil in the accumulator 1007 from flowing back to the oil tank 1001 when the hydraulic pump stops working.

[0033] Accumulator 1007 is used to store the pressurized hydraulic fluid required for the landing gear control system to operate. In this embodiment, the volume of accumulator 1007 is designed to ensure that the landing gear control system can complete two normal retraction and extension actions, so as to provide a short-term emergency hydraulic supply when hydraulic pump 1003 is not working.

[0034] Pressure sensor 1006 is installed on the pipeline near accumulator 1007 to monitor the oil supply pressure of the system and provide pressure feedback signals for system control.

[0035] II. Landing Gear Control System The first landing gear control device 2000 will be described in detail as an example. The structure of the second landing gear control device 3000 is exactly the same, so it will not be described in detail again.

[0036] Reference Figure 1The first landing gear control device 2000 includes: a first landing gear control combination valve 2100, a second landing gear control combination valve 2200, a pressure reducing valve 2001, a first hydraulic lock control combination valve 2400, a second hydraulic lock control combination valve 2300, a first balance valve 2002, a second balance valve 2003, multiple pressure sensors (2004-2009), a first landing gear actuator 2010, a second landing gear actuator 2011, a first landing gear upper lock actuator 2012, a second landing gear upper lock actuator 2013, a first landing gear lower lock actuator 2014, and a second landing gear lower lock actuator 2015.

[0037] (I) Structure of array-type combination valve The core component of this invention is an "array-type combination valve" for controlling the landing gear actuator cylinder, which is specifically implemented in this embodiment as a "landing gear control combination valve 2100".

[0038] Reference Figure 2 The landing gear control combination valve 2100 is composed of multiple on / off solenoid valves combined according to a specific topology, specifically including: a first normally closed solenoid valve 2101, a second normally closed solenoid valve 2102, a first normally open solenoid valve 2103, and a second normally open solenoid valve 2104.

[0039] The landing gear control combination valve 2100 has four oil ports: First oil port (P port): Connected to the oil supply pipeline of oil source device 1000, used to introduce high-pressure oil; Second oil port (T port): connected to the return oil pipeline of oil source device 1000, used to drain oil back to oil tank 1001; Third oil port (port A): connected to the rodless cavity of the first landing gear actuator 2010; Fourth oil port (B port): connected to the rod chamber of the first landing gear actuator cylinder 2010.

[0040] The connection relationship of the four solenoid valves is as follows: The first normally closed solenoid valve 2101 is connected between the first oil port (P port) and the fourth oil port (B port); The second normally closed solenoid valve 2102 is connected between the first oil port (P port) and the third oil port (A port); The first normally open solenoid valve 2103 is connected between the second oil port (T port) and the third oil port (A port); The second normally open solenoid valve 2104 is connected between the second oil port (T port) and the fourth oil port (B port).

[0041] This "two normally open + two normally closed" topology has the following technical characteristics: 1. Switch control: By controlling the combination of the energized / de-energized states of the four solenoid valves, the pressure oil entering the rod-side or rodless side of the actuator can be precisely controlled to achieve the extension or retraction of the landing gear.

[0042] 2. Fail-safe function: When the system loses power, the two normally closed valves (2101, 2102) automatically close, cutting off the oil supply; the two normally open valves (2103, 2104) automatically open, simultaneously connecting the rodless chamber and rod chamber of the actuator cylinder to the return oil circuit. At this time, the landing gear can fall freely under its own weight, realizing emergency deployment and greatly improving system safety.

[0043] (II) Structure of the hydraulic lock control combination valve Reference Figure 3 The hydraulic lock control combination valve 2400 also adopts an array-type switching valve design, including a third normally closed solenoid valve 2401 and a fourth normally closed solenoid valve 2402.

[0044] The hydraulic lock control combination valve 2400 has three oil ports: Fifth oil port: connected to the oil supply line of oil source device 1000 via pressure reducing valve 2001; Sixth oil port: Connected to the return oil pipeline of oil source device 1000; Seventh oil port: Connected to the control cavity of the upper landing gear lock actuator 2012 (or lower landing gear lock actuator 2014).

[0045] The connection relationship between the two solenoid valves is as follows: The third normally closed solenoid valve 2401 is connected between the fifth oil port and the seventh oil port; The fourth normally closed solenoid valve 2402 is connected between the sixth and seventh oil ports.

[0046] (iii) Auxiliary hydraulic components Pressure reducing valve 2001 is installed on the oil supply line between oil source device 1000 and hydraulic lock control combination valve 2400 / 2300. It is used to reduce the system oil supply pressure to the preset pressure value required by the lock actuator (such as 8.5MPa) to meet the working requirements of the lock actuator and protect its structure.

[0047] The first balance valve 2002 and the second balance valve 2003 are respectively located between the rodless chamber oil passage and the rod chamber oil passage of the first landing gear actuator 2010 and the second landing gear actuator 2011. The balance valve adopts the principle of hydraulic control unidirectional throttling. When the array-type combination valve is controlled to open and close, the balance valve can automatically adjust the return oil throttling area according to the load change, effectively resisting the pressure shock caused by sudden load changes, and ensuring that the landing gear can operate smoothly under different load conditions.

[0048] Pressure sensors 2004-2009 were installed at various key oil circuit nodes: Pressure sensors 2004 and 2005: monitor the pressure in the rodless and rod chambers of the first landing gear actuator cylinder 2010; among them, pressure sensor 2004 monitors the pressure in the rod chamber, and pressure sensor 2005 monitors the pressure in the rodless chamber. Pressure sensors 2006 and 2007: monitor the pressure in the rodless and rod chambers of the second landing gear actuator 2011; among them, pressure sensor 2006 monitors the pressure in the rod chamber, and pressure sensor 2007 monitors the pressure in the rodless chamber. Pressure sensors 2008 and 2009: monitor the pressure in the control chamber of the lock actuator.

[0049] These pressure sensors feed real-time pressure signals back to the control system for closed-loop control, fault diagnosis, and condition monitoring.

[0050] Example 2: Landing Gear Extension Control Process The following is combined Figure 1-3 Taking the extension process of the first landing gear actuator 2010 as an example, the specific working process of the control system of the present invention will be described in detail.

[0051] Step 1: Unlock the upper lock Upon receiving the landing gear extension command, the control system first unlocks the master lock, creating conditions for the landing gear to extend: The third normally closed solenoid valve 2401 is energized and opens, while the fourth normally closed solenoid valve 2402 remains de-energized and closed. The pressurized oil supplied by the accumulator 1007 flows through the pressure reducing valve 2001, reducing the pressure to the preset 8.5 MPa. The depressurized oil then enters the rodless chamber of the first landing gear upper lock actuator cylinder 2012 through the third normally closed solenoid valve 2401, pushing the piston rod to move and unlocking the upper lock.

[0052] The pressure sensor 2008 monitors the control chamber pressure in real time to ensure that the unlocking pressure is within the normal operating range.

[0053] Step 2: Landing gear extends After the upper lock is unlocked, the control system controls the array-type combination valve to operate: The second normally closed solenoid valve 2102 is energized and opens, while the first normally open solenoid valve 2103 is energized and closes. The first normally closed solenoid valve 2101 remains de-energized and closed, while the second normally open solenoid valve 2104 remains de-energized and open (because it is a normally open valve, it is open when de-energized).

[0054] The pressurized hydraulic fluid supplied by the accumulator 1007 enters the rodless chamber of the first landing gear actuator 2010 via the second normally closed solenoid valve 2102. Under hydraulic pressure, the piston rod extends, driving the landing gear to lower. Simultaneously, the hydraulic fluid in the rod chamber of the actuator is squeezed by the piston and enters the system return oil passage via the second normally open solenoid valve 2104 (which is currently open), ultimately flowing back to the oil tank 1001.

[0055] During the extension process, the second balance valve 2003 monitors load changes in real time. When a sudden load change occurs (such as the landing gear crossing the dead center position), the balance valve automatically adjusts the return oil throttling area to prevent the piston rod from accelerating suddenly and ensure a smooth extension process.

[0056] Pressure sensors 2004 and 2005 monitor the pressure in both chambers of the actuator in real time, providing feedback to the control system.

[0057] Step 3: Extend and lock in place Once the landing gear has extended to its full position, the control system engages a locking mechanism. First, all solenoid valves in the landing gear control combination valve 2100 are de-energized: the second normally closed solenoid valve 2102 is de-energized and closes, cutting off the oil supply to the rodless chamber; the first normally open solenoid valve 2103 is de-energized and opens, connecting the rodless chamber to the return oil circuit; the second normally open solenoid valve 2104 remains open, connecting the rod chamber to the return oil circuit. At this time, both chambers of the actuator are connected to the return oil circuit, and the landing gear actuator is in a floating state.

[0058] Meanwhile, since the landing gear has moved to the lowered position, the first landing gear lower lock actuator 2014 automatically locks under the action of a mechanical structure (for example, the lock hook falls into the lock groove by spring force or its own weight), without the need for hydraulic control. This lower lock locks the piston rod of the landing gear actuator 2010 in the extended position, preventing it from retracting accidentally.

[0059] At this point, the landing gear extension control process is complete.

[0060] Example 3: Landing Gear Retraction Control Process The following section uses the retraction process of the first landing gear actuator 2010 as an example to explain in detail the specific workflow of landing gear retraction.

[0061] Step 1: Unlock the lower-level lock Upon receiving the landing gear retraction command, the control system first unlocks the lower-level lock: Taking the first landing gear lower position lock actuator 2014 as an example, the normally closed solenoid valve in the corresponding hydraulic lock control combination valve is energized and opened. The pressurized oil provided by the accumulator 1007 is reduced to 8.5MPa by the pressure reducing valve 2001 and then enters the rodless chamber of the first landing gear lower position lock actuator 2014, pushing the piston rod to move and driving the lower position lock to unlock.

[0062] Step 2: Landing gear retraction After the lower-level lock is unlocked, the control system controls the array-type combination valve to operate: The first normally closed solenoid valve 2101 is energized and opens, while the second normally open solenoid valve 2104 is energized and closes. The second normally closed solenoid valve 2102 remains de-energized and closed, and the first normally open solenoid valve 2103 remains de-energized and open.

[0063] The pressurized hydraulic fluid supplied by the accumulator 1007 enters the rod chamber of the first landing gear actuator 2010 via the first normally closed solenoid valve 2101. Under hydraulic pressure, the piston rod begins to retract, driving the landing gear to retract upwards. Simultaneously, the hydraulic fluid in the rodless chamber of the actuator is squeezed by the piston and enters the system return oil passage via the first normally open solenoid valve 2103 (which is currently open), eventually flowing back to the oil tank 1001.

[0064] During the retraction process, the second balancing valve 2003 also plays a role, automatically adjusting the throttling according to load changes to ensure a smooth retraction process.

[0065] Step 3: Retract and lock into place Once the landing gear has retracted to its final position, the control system will lock the landing gear in place. The control system de-energizes all solenoid valves in the landing gear control combination valve 2100: the first normally closed solenoid valve 2101 closes, cutting off the oil supply; the second normally open solenoid valve 2104 opens, connecting the rod chamber to the return oil circuit; the first normally open solenoid valve 2103 remains open, connecting the rodless chamber to the return oil circuit. Both chambers of the actuator are connected to the return oil circuit, and the landing gear actuator is in a floating state.

[0066] At this point, once the landing gear has retracted to its retracted position, the first landing gear upper lock actuator 2012 automatically locks due to the mechanical structure (for example, the lock hook falls into the lock groove by spring force), locking the landing gear in the retracted position without the need for hydraulic control.

[0067] At this point, the landing gear retraction control process is complete.

[0068] Example 4: Fail-Safe Function Verification The control system of this invention has important fail-safe functions, which will be explained below by simulating the power failure condition of the system.

[0069] Suppose that during train operation, while the landing gear is lowering, the system loses power (e.g., a power failure). At this time: All solenoid valves in the landing gear control combination valve 2100 are de-energized: the first normally closed solenoid valve 2101 and the second normally closed solenoid valve 2102 automatically close, cutting off the high-pressure oil supply; the first normally open solenoid valve 2103 and the second normally open solenoid valve 2104 automatically open, simultaneously connecting the rodless chamber and the rod chamber of the first landing gear actuator 2010 to the return oil line.

[0070] Since both chambers of the actuator are connected to the return oil circuit, there is no longer a pressure difference between the rodless chamber and the rod chamber, and the oil can flow freely. Under its own weight, the landing gear overcomes hydraulic resistance, automatically extends downward, and finally lowers completely.

[0071] Similarly, the normally closed solenoid valve in the hydraulic lock control combination valve closes when de-energized, and the lock actuator remains in its current state; however, when the landing gear is lowered by gravity, the lower locking mechanism can mechanically lock the landing gear in the lowered position to ensure train safety.

[0072] This fail-safe feature requires no additional manual operation or emergency circuit; it relies solely on the inherent characteristics of the valve, greatly enhancing the system's safety under extreme conditions.

[0073] Example 5: System Integration and Layout Optimization In this embodiment, the first landing gear control device 2000 and the second landing gear control device 3000 adopt a modular integrated design: Hydraulic components such as the landing gear control combination valve, hydraulic lock control combination valve, pressure reducing valve, balance valve, and pressure sensor are integrated and packaged in two independent valve group modules, which are respectively installed on both sides of the suspension frame. Each module controls two landing gear actuators and their corresponding lock actuators.

[0074] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention without departing from the principles and spirit of the present invention.

Claims

1. A magnetic levitation train landing gear control system based on an array-type combined valve, applied to magnetic levitation trains in strong magnetic field environments, characterized in that... include: An oil supply unit is used to store and supply pressurized oil to the system; At least one landing gear control device is mounted on the suspension frame of the maglev train, and each of the landing gear control devices includes: At least one landing gear actuator for driving the extension or retraction of the landing gear; An array-type combination valve is connected between the oil source device and the landing gear actuator cylinder. The array-type combination valve consists of multiple on / off solenoid valves. By controlling the combination of the energized and de-energized states of the multiple on / off solenoid valves, the pressure oil is controlled to enter or exit different working chambers of the landing gear actuator cylinder to realize the extension or retraction of the landing gear. The oil circuit connection of the array-type combination valve is configured to have a fail-safe function. When the system loses power, the array-type combination valve automatically connects the working chamber of the landing gear actuator cylinder with the return oil circuit so that the landing gear can be lowered by gravity in an emergency.

2. The magnetic levitation train landing gear control system based on array-type combined valves according to claim 1, characterized in that: The array-type combination valve includes a landing gear control combination valve for controlling individual landing gear actuators; The landing gear control combination valve includes a first normally closed solenoid valve, a second normally closed solenoid valve, a first normally open solenoid valve, and a second normally open solenoid valve. The landing gear control combination valve is provided with a first oil port, a second oil port, a third oil port and a fourth oil port. The first oil port is connected to the oil supply line of the oil source device, the second oil port is connected to the oil return line of the oil source device, the third oil port is connected to the rodless chamber of the landing gear actuator, and the fourth oil port is connected to the rod chamber of the landing gear actuator. The first normally closed solenoid valve is connected between the first oil port and the fourth oil port, the second normally closed solenoid valve is connected between the first oil port and the third oil port, the first normally open solenoid valve is connected between the second oil port and the third oil port, and the second normally open solenoid valve is connected between the second oil port and the fourth oil port.

3. The magnetic levitation train landing gear control system based on array-type combined valves according to claim 1, characterized in that: Each of the landing gear control devices further includes: At least one upper lock actuator is used to lock or unlock the landing gear in the retracted state; At least one lower locking actuator is used to lock or unlock the landing gear in the extended position; The hydraulic lock control combination valve consists of multiple on / off solenoid valves connected between the oil source device and the upper and lower lock actuators, and is used to control the unlocking of the upper and lower lock actuators. A pressure reducing valve is installed on the oil supply line between the oil source device and the hydraulic lock control combination valve. It is used to reduce the oil supply pressure to the preset pressure value required by the lock actuator.

4. The magnetic levitation train landing gear control system based on array-type combined valves according to claim 3, characterized in that: The hydraulic lock control combination valve includes a third normally closed solenoid valve and a fourth normally closed solenoid valve. The hydraulic lock control combination valve is provided with a fifth oil port, a sixth oil port and a seventh oil port. The fifth oil port is connected to the oil supply circuit of the oil source device via a pressure reducing valve. The sixth oil port is connected to the return oil circuit of the oil source device. The seventh oil port is connected to the control chamber of the upper lock actuator or the lower lock actuator. The third normally closed solenoid valve is connected between the fifth and seventh oil ports, and the fourth normally closed solenoid valve is connected between the sixth and seventh oil ports.

5. The magnetic levitation train landing gear control system based on array-type combined valves according to claim 4, characterized in that: Each of the landing gear control devices also includes a balance valve, which is located between the rodless chamber oil passage and the rod chamber oil passage of the landing gear actuator. The balance valve is used to throttle the return oil of the actuator through hydraulic control when the array-type combination valve is switched on and off, so as to resist the pressure shock caused by sudden load changes and ensure the smooth operation of the landing gear.

6. The magnetic levitation train landing gear control system based on array-type combined valves according to claim 5, characterized in that: Each landing gear control device also includes multiple pressure sensors, which are respectively installed in the rodless chamber oil circuit, the rod chamber oil circuit, and the control chamber oil circuit of the landing gear actuator, for real-time monitoring of the pressure of each oil circuit.

7. The magnetic levitation train landing gear control system based on array-type combined valves according to claim 1, characterized in that: The control system includes multiple landing gear control devices, which are installed on both sides of the same suspension frame of the maglev train to independently control the landing gear on both sides, thereby achieving balance of vehicle load and symmetry of layout.

8. The magnetic levitation train landing gear control system based on array-type combined valves according to claim 1, characterized in that: The oil source device includes: The fuel tank stores the control fluid required for the landing gear system. An electric motor and a hydraulic pump driven by the electric motor are used to draw oil from the oil tank; An accumulator, located at the outlet of the hydraulic pump, is used to store pressurized oil and provide a pressurized oil source for the landing gear control system. A check valve is installed between the hydraulic pump and the accumulator to prevent the oil in the accumulator from flowing back.

9. A method for controlling the landing gear of a magnetic levitation train based on the system described in any one of claims 1-8, characterized in that, Including landing gear extension control procedures: Step 1: After receiving the landing gear extension command, the normally closed solenoid valve in the hydraulic lock control combination valve is energized and opened, so that the pressure oil after being reduced by the pressure reducing valve enters the rodless chamber of the corresponding upper lock actuator cylinder, driving the upper lock to unlock. Step 2: The normally closed solenoid valve connected to the rodless chamber of the landing gear actuator cylinder in the control array combination valve is energized and opened, and at the same time the normally open solenoid valve connected to the rodless chamber is energized and closed, so that the pressurized oil enters the rodless chamber of the landing gear actuator cylinder, and the oil in the rod chamber returns through the array combination valve, driving the landing gear to extend. Step 3: After the landing gear is extended to the position, all solenoid valves in the control array combination valve are de-energized, which connects the two chambers of the landing gear actuator cylinder to the return oil circuit. At the same time, the normally closed solenoid valve in the control hydraulic lock combination valve is energized and opened, which allows the oil in the rodless chamber of the lock actuator cylinder to return. The lock actuator cylinder retracts under the action of the return spring, locking the landing gear in the extended position.

10. A method for controlling the landing gear of a magnetic levitation train based on the system described in any one of claims 1-8, characterized in that, Including landing gear retraction control procedures: Step 1: After receiving the landing gear retraction command, the normally closed solenoid valve in the hydraulic lock control combination valve is energized and opened, so that the pressure oil after being reduced by the pressure reducing valve enters the rodless chamber of the corresponding lower lock actuator cylinder, driving the lower lock to unlock. Step 2: The normally closed solenoid valve connected to the rod chamber of the landing gear actuator cylinder in the array-type combination valve is energized and opened, while the normally open solenoid valve connected to the rod chamber is energized and closed, so that the pressurized oil enters the rod chamber of the landing gear actuator cylinder, and the oil in the rodless chamber returns through the array-type combination valve, driving the landing gear to retract. Step 3: After the landing gear is retracted to the position, all solenoid valves in the control array combination valve are de-energized, connecting the two chambers of the landing gear actuator cylinder to the return oil circuit. At the same time, the normally closed solenoid valve in the control hydraulic lock combination valve is energized and opened, allowing the oil in the rodless chamber of the lock actuator cylinder to return. The lock actuator cylinder retracts under the action of the return spring, locking the landing gear in the retracted position.

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