CN115783250A - Undercarriage stay bar unlocking electro-hydrostatic actuator and working method - Google Patents
Undercarriage stay bar unlocking electro-hydrostatic actuator and working method Download PDFInfo
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Abstract
The invention relates to the technical field of aircraft accessory design, in particular to an undercarriage stay bar unlocking electro-hydrostatic actuator and a working method thereof.
Description
Technical Field
The invention relates to the technical field of aircraft accessory design, in particular to an undercarriage strut unlocking electro-hydrostatic actuator and a working method thereof.
Background
The landing gear strut lock mechanism is an important component of a main landing gear retraction system and is one of necessary mechanisms for ensuring safe taking off and landing of an airplane. When the landing gear is in a lowering state, the lock mechanism locks the landing gear support rod at a locking position through the locking spring, so that the landing gear bears ground load during sliding; when the undercarriage is contracted and folded, the stay bar lock mechanism is adjusted to the unlocking position from the locking position through hydraulic pressure, so that the undercarriage can be folded along with contraction external load follow-up, and the undercarriage is folded and unfolded.
The landing gear support rod adopts a folding structure and consists of an upper support rod, a lower support rod and a lock mechanism. The lock mechanism consists of a connecting rod, a rocker arm and a support rod actuating cylinder. The stay bar actuating cylinder is provided with a locking spring, and the locking of the landing gear stay bar is completed through the spring force of the locking spring; the strut rod actuator cylinder is driven by hydraulic pressure provided by an aircraft hydraulic source to contract, and drives the rocker arm to rotate to complete unlocking of the undercarriage strut rod.
Due to the size limitation of the aircraft landing gear, the external size and the weight of the landing gear stay bar are highly limited. The axial size of the strut piston cylinder can be effectively shortened by adopting a single-rod double-acting form (namely an asymmetric piston cylinder). However, the asymmetric piston cylinder design mode can cause the piston rod to extend out slower than retract under the action of the same flow of hydraulic oil.
Patents [ application No.: CN201410612889.9 has proposed a undercarriage vaulting pole pressurized strut with function control valve, and this patent adds the control valve on the pressurized strut and is used for controlling the oil mass of asymmetric pressurized strut two chambeies, can realize hydraulic lock function and the fluid compensation function of asymmetric pressurized strut. The method increases the structural complexity of the hydraulic system of the landing gear, causes the problems of increased weight, reduced reliability and the like, and cannot be used when the hydraulic system fails.
Patents [ application No.: CN201410592407.8 proposes a multifunctional undercarriage supporting rod device, which can realize the supporting, the up-down locking and the retraction driving of a small and medium-sized aircraft undercarriage. The hydraulic control landing gear locking device comprises an actuator cylinder assembly, a function control valve assembly and an upper and lower position lock elastic clamping jaw, wherein the actuator cylinder assembly finishes retraction and release of a landing gear under the hydraulic pressure effect of a hydraulic system, and upper and lower position locking of a landing gear support rod is realized through the elastic clamping jaw. The method completes the locking function of the stay bar through a mechanical device, but the extension and the retraction of the stay bar are controlled through an external hydraulic source.
Patents [ application No.: CN201020267183.0 ] proposes an aircraft landing gear strut lock mechanism, where unlocking and locking of the strut lock are both completed by a retractable actuator cylinder, when the landing gear is in a lowering position, a strut is fixed at a locking position by a compression spring on the strut lock, the locking force is provided by a spring force, passive locking of the strut can still be completed when a hydraulic system fails, but unlocking of the lock mechanism needs to be supplied by energy of an external hydraulic source.
The existing patent finishes the retraction of the stay bar through an external hydraulic source, and when a hydraulic system breaks down, a hydraulic energy source needing to be backed up provides temporary hydraulic energy to ensure the normal work of the undercarriage. As an electromechanical hydraulic system integrating a motor, a pump, a valve, a sensor and a tail end execution part, the electro-hydrostatic actuator has advantages in various aspects such as reliability, safety, maintainability and economy compared with a traditional hydraulic execution mechanism, and gradually occupies the modern hydraulic actuation market, and the research and development of the high-performance electro-hydrostatic actuator become the focus of global aircraft hydraulic suppliers, but the electro-hydrostatic actuator is rarely applied to an undercarriage system.
In summary, an unlocking actuator capable of intelligently achieving retraction and passive locking of a stay bar and achieving the function of moving along with the main structure of the landing gear is needed, the unlocking actuator has the unlocking function, can meet passive locking, and has certain advantages in the aspects of system complexity, reliability, weight and the like.
Disclosure of Invention
The purpose of the invention is as follows: in order to solve the problems of complex system, increased weight, low reliability and the like of the existing undercarriage stay bar lock mechanism, the invention provides an undercarriage unlocking electro-hydrostatic actuator and a working method thereof, and the functions of active unlocking, automatic locking, passive movement along with an undercarriage and the like of an undercarriage stay bar can be realized through simple control logic.
The invention is realized by the following technical scheme:
the undercarriage strut unlocking electro-hydrostatic actuator comprises a controller 1, a motor driver 2, a motor 3, a hydraulic pump 4, an overflow valve 5, a shuttle valve 6, a damping hole 7, an oil injection check valve 8, an exhaust check valve 9, an energy accumulator 10, a piston cylinder 11, a locking spring 12 and a piston rod displacement sensor 13, wherein the controller 1, the motor driver 2, the motor 3 and the hydraulic pump 4 are sequentially and electrically connected, an inlet of the hydraulic pump 4 is sequentially connected with an oil injection check valve 8, an exhaust check valve 9, the energy accumulator 10 and an extending cavity of the piston cylinder 11 through an oil way, an outlet of the hydraulic pump 4 is sequentially connected with the overflow valve 5, the shuttle valve 6 and a retracting cavity of the piston cylinder 11 through the oil way, the overflow valve 5 is connected with the oil way of the oil injection check valve 8, the shuttle valve 6 is connected with the oil way of the exhaust check valve 9 through the damping hole 7, and the locking spring 12 is coaxially installed on a piston rod shaft of the piston cylinder 11.
Further, the device also comprises a piston rod displacement sensor 13, wherein the piston rod displacement sensor 13 is installed on a piston rod shaft of the piston cylinder 11, is electrically connected with the controller 1, and is used for monitoring the motion position of the piston rod shaft.
Further, the hydraulic system further comprises a temperature and pressure sensor 14, wherein the temperature and pressure sensor 14 is installed on an oil circuit close to the energy accumulator 10, is connected with the controller and is used for monitoring the temperature and the pressure of the oil circuit inside the hydraulic system.
Further, still include motor speed sensor 15, motor speed sensor 15 installs on motor 3, is connected with the controller for feedback motor speed.
Further, a current feedback sensor 16 is further included, and the current feedback sensor 16 is installed on a bus of the motor driver 2 connected with the motor and used for monitoring the bus current.
Furthermore, the piston cylinder 11 is an asymmetric piston cylinder and is used for shortening the axial length of the piston cylinder 11, an extension cavity D and a retraction cavity F of the piston cylinder are communicated with the shuttle valve 6 through a damping hole 7, when the stay bar is in a locking state, the extension cavity and the retraction cavity of the piston cylinder are communicated with each other, the pressure of the two cavities is the same, the area of the extension cavity is larger than that of the retraction cavity, so that the piston rod can be subjected to outward extension force of the extension cavity, meanwhile, under the acting force of a locking spring 12, the piston rod extends outwards, the two ends of the piston cylinder are connected with a main body structure of the undercarriage stay bar through an ear ring and a joint bearing, and the piston rod is driven to move when the main body structure of the stay bar contracts.
Furthermore, one end of the locking spring 12 is in contact with the cylinder body of the piston cylinder 11, the other end of the locking spring is in contact with a flange on the piston rod, the locking spring 12 has a certain pre-compression amount, and the resultant force of the spring force provided by the pre-compression amount and the hydraulic pressure of the asymmetric piston cylinder provides the required locking force for the landing gear strut unlocking electro-hydrostatic actuator.
Further, the shuttle valve 6 comprises a normally closed oil inlet A, a normally open oil inlet B and an oil outlet C, the normally open oil inlet B of the shuttle valve 6 is connected with the damping hole 7 and leads to an extending cavity D of the piston cylinder 11 and the energy accumulator 10; a normally closed oil inlet A of the shuttle valve is connected with the output end of the hydraulic pump 4; an oil outlet C of the shuttle valve 6 is connected with a retraction cavity F of the piston cylinder 11, and the shuttle valve 6 switches an oil path leading to the retraction cavity F of the piston cylinder 11 through a normally closed oil inlet A, a normally open oil inlet B and the working state of the hydraulic pump.
Furthermore, one end of the damping hole is connected with the extending cavity D of the piston cylinder 11, and the other end of the damping hole is connected with the retracting cavity F of the piston cylinder 11 through a normally-open oil inlet B of the shuttle valve.
The working method for unlocking the electro-hydrostatic actuator by the landing gear strut comprises the following steps:
(1) Firstly, judging whether the undercarriage is ready to contract or not, if not, not sending an unlocking instruction to the controller 1, at the moment, the controller 1, the motor driver 2, the motor 3 and the hydraulic pump 4 do not work, the shuttle valve keeps a normally closed oil inlet A in a closed state, under the action of the spring force of the upper locking spring 12, a piston rod of the piston cylinder 11 extends out to reach a limit position, a strut rocker arm and a connecting rod cross the extreme point of a mechanism, so that the upper strut and the lower strut cannot be folded, and the undercarriage strut unlocking electro-hydrostatic actuator is in a locked state;
(2) If the undercarriage is ready to contract and an unlocking instruction is sent to the controller 1, the controller 1 and the motor driver 2 are powered on, then the controller 1 judges whether the unlocking instruction is received, if the unlocking instruction is not received within a specified time, the motor 3 is powered off, the shuttle valve 6 keeps the normally closed oil inlet A in a closed state, at the moment, a piston rod of the piston cylinder 11 is still in a limit position, and the undercarriage strut unlocking electro-hydrostatic actuator is still in a locked state;
(3) If an unlocking instruction is received, the motor 3 is electrified to drive the hydraulic pump 4 to rotate, the normally closed oil inlet A of the shuttle valve 6 is opened under the impact of hydraulic pressure, hydraulic oil flows into the retraction cavity F of the piston cylinder, so that the piston rod shaft retracts, at the moment, whether unlocking action is finished or not is judged through a displacement signal fed back by the piston rod position sensor 13, if the piston rod reaches a specified position to finish the unlocking action, the motor 3 is electrified, the valve core of the shuttle valve 6 returns to the normally closed oil inlet A under the action of the built-in spring force of the shuttle valve, the oil circuit of the extension cavity D and the retraction cavity F of the piston cylinder 11 is switched to a communication state, at the moment, the piston rod is in a non-limit extension position and can be retracted/extended along with the folding of the undercarriage, and the undercarriage strut unlocking electro-hydrostatic actuator is in a follow-up state;
(4) If the displacement fed back by the piston rod position sensor 13 does not reach the designated position, the motor 3 keeps moving all the time, the hydraulic pump 4 is driven to convey hydraulic oil to drive the piston rod to do contraction movement, and the undercarriage strut unlocking electro-hydrostatic actuator is in an unlocking state until the displacement stroke required by the unlocking action is completed.
Compared with the prior art, the invention has the following beneficial effects:
(1) The invention adopts the electro-hydrostatic actuator to realize the unlocking, locking and follow-up of the landing gear stay bar, wherein only the unlocking function system needs to be electrified, the system can be passively locked and followed up under the condition of electrification, the control logic is simple, and the structure is practical;
(2) The invention omits a complex function control valve, and the switching of the oil circuit is completed through the shuttle valve, thereby improving the reliability of the system;
(3) The invention contains various sensors, can be used for monitoring various states (current, temperature and pressure of oil and position of a piston rod) of the system, and intelligently identifies the unlocking state of the landing gear unlocking electro-hydrostatic actuator, and has strong monitoring capability and high intelligent degree;
(4) The invention has simple principle, realizes the unlocking function by adopting the passive shuttle valve on the premise of not increasing the complexity of a hydraulic system, realizes the locking function by a spring, does not need an actively controlled mode valve and an electromagnetic valve, and has simple system control logic and high reliability.
Drawings
FIG. 1 is a block diagram of a system for a landing gear unlocking electro-hydrostatic actuator.
FIG. 2 is an unlocking logic diagram for a landing gear unlocking electro-hydrostatic actuator.
Fig. 3 is a hydraulic schematic diagram of the actuator in the unlocked state.
Fig. 4 is a schematic diagram of the hydraulic pressure in the locked state of the actuator.
Fig. 5 is a hydraulic schematic diagram of the actuator in the follow-up state.
FIG. 6 is a schematic view of a structural connection of a landing gear unlocking electro-hydrostatic actuator to a landing gear strut;
the device comprises a controller 1, a motor driver 2, a brushless direct current motor 3, a hydraulic pump 4, an overflow valve 5, a shuttle valve 6, a damping hole 7, an oil injection check valve 8, an exhaust check valve 9, an energy accumulator 10, a piston cylinder 11, a locking spring 12, a piston rod displacement sensor 13, a temperature pressure sensor 14, a motor speed sensor 15 and a current feedback sensor 16.
Detailed Description
The utility model provides an undercarriage unblock electro-hydrostatic actuator, including controller 1, motor drive 2, brushless DC motor 3, hydraulic pump 4, overflow valve 5, shuttle valve 6, damping hole 7, oiling individual item valve 8, take the exhaust check valve 9 of manual relief port, energy storage ware 10, piston cylinder 11, locking spring 12, piston rod position sensor 13 (be used for detecting the piston rod position), fluid temperature pressure sensor 14 (the interior fluid temperature pressure of detecting system), motor speed sensor 15 (be used for detecting motor speed) and current feedback sensor 16 (be used for the detection current).
The hydraulic control system is characterized in that the controller 1, the motor driver 2, the motor 3 and the hydraulic pump 4 are sequentially and electrically connected, an inlet of the hydraulic pump 4 is sequentially connected with an oil injection one-way valve 8, an exhaust one-way valve 9, the energy accumulator 10 and an extending cavity of the piston cylinder 11 through an oil way, an outlet of the hydraulic pump 4 is sequentially connected with an overflow valve 5, a shuttle valve 6 and a retracting cavity of the piston cylinder 11 through an oil way, the overflow valve 5 is connected with the oil way of the oil injection one-way valve 8, the shuttle valve 6 is connected with the oil way of the exhaust one-way valve 9 through a damping hole 7, a locking spring 12 is coaxially installed on a piston rod shaft of the piston cylinder 11, and a piston rod displacement sensor 13 is installed on the piston rod shaft of the piston cylinder 11, is electrically connected with the controller and is used for monitoring the movement position of the piston rod shaft. A temperature and pressure sensor 14 is mounted on the oil circuit near the accumulator 10 and is connected to the controller for monitoring the temperature and pressure of the oil circuit inside the hydraulic system. The motor speed sensor 15 is installed on the motor 3, electrically connected with the controller, and used for feeding back the motor speed. A current feedback sensor 16 is mounted on the bus of the motor driver 2 connected to the motor for monitoring the bus current.
Furthermore, the piston cylinder 11 adopts an asymmetric cavity design for shortening the axial length of the actuator. The piston cylinder 11 is connected with the shuttle valve 6 through the damping hole 7 between the extending cavity and the retracting cavity. When the stay bar is in a locking state, the piston cylinder 11 extends out of the cavity and is communicated with the retraction cavity, the pressure of the two cavities is the same, and the area of the extension cavity is larger than that of the retraction cavity, so that the piston rod can be subjected to outward extension force of the extension cavity, and the piston rod can extend outwards. The two ends of the piston cylinder 11 are connected with the main body structure of the supporting rod of the undercarriage through the ear rings and the joint bearings, and the main body structure of the supporting rod drives when being contracted
Further, a compression spring, i.e. a locking spring 12, is coaxially mounted on the piston rod shaft for providing a locking force of the actuator, and is connected to the cylinder 11 at one end and to the flange on the piston rod at the other end, and has a certain precompression amount, and the resultant of the spring force provided by the precompression amount and the asymmetric piston rod hydraulic pressure provides the required locking force of the actuator.
Further, the shuttle valve 6 is used to switch the locking, unlocking, and follow-up functions of the actuator. A normally open oil inlet of the shuttle valve 6 is connected with the damping hole 7 and leads to an oil tank and an extension cavity of the piston cylinder 11; a normally closed oil inlet of the shuttle valve 6 is connected with the output end of the hydraulic pump 4; the working port of the shuttle valve 6 is connected to the retraction cavity of the piston cylinder 11. The shuttle valve 6 determines the oil source of the retraction cavity of the piston cylinder 11 through two oil inlets and the working state of the hydraulic pump 4.
Further, the orifice 7 is used for communication between the piston cylinder 11 extending and retracting chambers in the locked and following states. One end of the damping hole 7 is connected with the extending cavity of the piston cylinder 11, and the other end of the damping hole is connected with the retracting cavity of the piston cylinder 11 through a normally open oil inlet of the shuttle valve 6. When the unlocking actuator is in a follow-up state, the damping hole 7 is used for providing damping buffering when the piston rod moves, and the piston rod is guaranteed to move stably.
Furthermore, the unlocking actuator also comprises an overflow valve 5 which is used for limiting the maximum pressure in the unlocking actuator, the overflow valve 5 is connected with two ends of the hydraulic pump 4, and the extending cavity and the retracting cavity are connected in parallel through a shuttle valve 6 and a piston cylinder 11; when the shuttle valve 6 opens the normally closed oil inlet in the unlocking process, the overflow valve 5 is directly communicated with two cavities of the piston cylinder 11 and is used for preventing the excessive pressure of the retraction cavity in the unlocking process.
Furthermore, the system comprises an oil filling one-way valve 8 which is connected with an energy accumulator 10 through a flow passage on the integrated valve block and is used for supplementing oil in the system.
Further, the device comprises an exhaust single-phase valve 9 with a manual air release port, and the exhaust single-phase valve is used for manually discharging gas separated out due to low pressure of hydraulic oil in the system or gas entering from the outside.
Furthermore, the energy accumulator 10 is used for compensating oil generated by the difference of the two cavity surfaces of the piston rod, providing a certain back pressure for the system, preventing the inside of the actuator from generating air pockets due to negative pressure, and supplementing the oil into the energy accumulator 10 through the oil injection one-way valve 8.
Furthermore, a temperature and pressure sensor 14 is included and used for detecting the temperature and the pressure of oil in the actuator, signals 14 of the temperature and pressure sensor are fed back to the controller, and the controller gives an alarm to the upper computer when the temperature and the pressure of the oil exceed a safety value.
Further, the operating method of the unlocking actuator is as follows:
(1) Firstly, judging whether the undercarriage is ready to contract or not, if not, not sending an unlocking instruction to the controller 1, at the moment, the controller 1, the motor driver 2, the motor 3 and the hydraulic pump 4 do not work, the shuttle valve keeps a normally closed oil inlet A in a closed state, under the action of the spring force of the upper locking spring 12, a piston rod of the piston cylinder 11 extends out to reach a limit position, a strut rocker arm and a connecting rod cross the extreme point of a mechanism, so that the upper strut and the lower strut cannot be folded, and the undercarriage strut unlocking electro-hydrostatic actuator is in a locked state;
(2) If the undercarriage is ready to contract and an unlocking instruction is sent to the controller 1, the controller 1 and the motor driver 2 are powered on, then the controller 1 judges whether the unlocking instruction is received, if the unlocking instruction is not received within a specified time, the motor 3 is powered off, the shuttle valve 6 keeps the normally closed oil inlet A in a closed state, the piston rod of the piston cylinder 11 is still in a limit position at the moment, and the undercarriage strut unlocking electro-hydrostatic actuator is still in a locked state;
(3) If an unlocking instruction is received, the motor 3 is powered on to drive the hydraulic pump 4 to rotate, the normally closed oil inlet A of the shuttle valve 6 is opened under the impact of hydraulic pressure, hydraulic oil flows into the piston cylinder retraction cavity F, so that the piston rod shaft is retracted, at the moment, whether the unlocking action is finished is judged through a displacement signal fed back by the piston rod position sensor 13, if the piston rod reaches a specified position to finish the unlocking action, the motor 3 is powered off, the valve core of the shuttle valve 6 returns to the normally closed oil inlet A under the action of a spring force arranged in the shuttle valve, the oil way of the piston cylinder 11 extending out of the cavity D and the retraction cavity F is switched to a communication state, the piston rod is located at a non-extreme extending position and can be retracted/extended along with the folding of the undercarriage, and the undercarriage strut unlocks the electro-hydrostatic actuator to be in a follow-up state;
(4) If the displacement fed back by the piston rod position sensor 13 does not reach the designated position, the motor 3 keeps moving all the time, the hydraulic pump 4 is driven to convey hydraulic oil to drive the piston rod to do contraction movement, and the undercarriage strut unlocking electro-hydrostatic actuator is in an unlocking state until the required displacement stroke of the unlocking action is completed.
Further, the unlocking function of the actuator is specifically as follows:
when the controller 1 receives an unlocking instruction, a driving signal is applied to the motor driver 2, the motor driver 2 drives the brushless direct current motor 3 to move, the brushless direct current motor 3 drives the hydraulic pump 4 to rotate, oil is supplied to the hydraulic pump 4 through the extending cavity of the energy accumulator 10 and the piston cylinder 11, the oil is pressurized by the hydraulic pump 4 and then is conveyed to the normally closed oil inlet of the shuttle valve 6, the valve core of the shuttle valve 6 is opened under the action of oil pressure, the normally closed oil inlet of the shuttle valve 6 is opened, the normally open oil inlet is closed, hydraulic oil output by the hydraulic pump 4 is conveyed to the retracting cavity of the piston cylinder 11 through the oil outlet of the shuttle valve 6, the piston rod is pushed to contract inwards, meanwhile, the piston rod displacement sensor 13 in the piston rod feeds back the piston rod unlocking displacement to the controller 1, and whether the piston rod moves to the unlocking position or not is judged through the controller 1.
Further, in an unlocking state, a valve core of the shuttle valve 6 is in a normally open oil inlet, a normally closed oil inlet of the shuttle valve 6 is opened, an extending cavity and a retracting cavity of the piston cylinder 11 are connected with the shuttle valve 6 through the hydraulic pump 4, and at the moment, a channel between the extending cavity and the retracting cavity of the piston cylinder 11 is closed.
Further, the locking function of the unlocking actuator is specifically:
when the actuator 1 needs to perform a locking function, the electro-hydrostatic actuator can complete locking without being powered on. At the moment, the piston rod is in a retraction state, the landing gear support rods connected with the two ends of the actuator do not have compression force applied to the two ends of the actuator from the outside when locking is executed, the controller 1 and the motor driver 2 do not need to be electrified, and the hydraulic pump 4 is in an inoperative state. When the piston rod is located the withdrawal position, the case of the shuttle valve 6 is located the normally closed oil inlet, the normally open oil inlet of the shuttle valve 6 is communicated with the oil outlet, the oil outlet is directly connected with the oil inlet of the retraction cavity of the piston cylinder 11, the normally closed oil inlet is connected with the extension cavity of the piston cylinder 11 through the damping hole 7, at the moment, two cavities of the piston cylinder 11 are communicated, a compression stroke exists in a compression spring between the piston rod and the cylinder body of the piston cylinder 11, under the action of the compression force of the spring, the piston rod extends outwards until the extreme extension position, the stay bar rocker arm and the connecting rod cross the limit of the mechanism, at the moment, the upper stay bar and the lower stay bar cannot be folded, and the locking function is completed.
Further, the following function of the unlocking actuator is specifically as follows:
when the actuator 1 needs to execute the follow-up function, the piston rod is in a non-limit position, and the undercarriage unlocking electro-hydrostatic actuator can complete the follow-up function without electrifying. The execution follow-up function is that the extension/compression force applied to the two ends of the actuator from the outside exists in the landing gear support rods connected with the two ends of the actuator, the controller 1 and the motor driver 2 do not need to be electrified, and the hydraulic pump 4 is in an inoperative state. The piston is in non-extreme position, and 6 case of shuttle valve still are in normally closed oil inlet, and normally open oil inlet and the oil-out of shuttle valve 6 communicate with each other, and the oil-out is direct to link to each other with 11 withdrawal chamber oil inlets of piston cylinder, and normally closed oil inlet stretches out the chamber with piston cylinder 11 through damping hole 7 and links to each other, and 11 two chambeies of piston cylinder communicate with each other this moment, can realize the follow-up function under the external force of actuator both ends vaulting pole: when the piston rod extends along with the support rod, oil in a retraction cavity of the piston cylinder 11 passes through an oil outlet of the shuttle valve 6, a normally open oil inlet and the damping hole 7 until the extension cavity of the piston cylinder 11, and because the volume of the hydraulic oil conveyed by the retraction cavity of the piston cylinder 11 is smaller than that of the extension cavity of the piston cylinder 11, the energy accumulator 10 conveys the oil to the extension cavity of the piston cylinder 11 to compensate the volume difference of the two cavities of the piston cylinder; when the piston rod retracts along with the supporting rod, oil in the piston cylinder extending cavity passes through the damping hole 7, the shuttle valve 6, the normally-open oil inlet and the oil outlet until the piston cylinder 11 retracts into the cavity, and because the volume of the hydraulic oil conveyed by the piston cylinder 11 extending cavity is larger than that of the piston cylinder 11 retracting cavity, redundant oil can be directly conveyed to the energy accumulator 10 from the piston cylinder 11 extending cavity.
Claims (10)
1. The undercarriage strut unlocking electro-hydrostatic actuator is characterized by comprising a controller, a motor driver, a motor, a hydraulic pump, an overflow valve, a shuttle valve, a damping hole, an oil injection check valve, an exhaust check valve, an energy accumulator, a piston cylinder, a locking spring and a piston rod displacement sensor, wherein the controller, the motor driver, the motor and the hydraulic pump are sequentially electrically connected, an inlet of the hydraulic pump is sequentially connected with an extending cavity of the oil injection check valve, the exhaust check valve, the energy accumulator and the piston cylinder through an oil way, an outlet of the hydraulic pump is sequentially connected with the overflow valve, the shuttle valve and a retracting cavity of the piston cylinder through an oil way, the overflow valve is connected with the oil injection check valve through an oil way, the shuttle valve is connected with the exhaust check valve through the damping hole, and the locking spring is coaxially installed on a piston rod shaft of the piston cylinder.
2. The landing gear strut unlock electro-hydrostatic actuator of claim 1, further comprising a piston rod displacement sensor mounted on a piston rod shaft of the piston cylinder and electrically connected to the controller for monitoring a position of movement of the piston rod shaft.
3. The landing gear strut unlocking electro-hydrostatic actuator as claimed in claim 1, further comprising a temperature and pressure sensor mounted on an oil line adjacent to the accumulator and connected to the controller for monitoring temperature and pressure of the oil line within the hydraulic system.
4. The landing gear strut unlocking electro-hydrostatic actuator according to claim 1, further comprising a motor speed sensor, wherein the motor speed sensor is mounted on the motor and connected to the controller for feeding back the motor speed.
5. The landing gear strut unlocking electro-hydrostatic actuator of claim 1, further comprising a current feedback sensor mounted on a bus of the motor driver connected to the motor for monitoring bus current.
6. The undercarriage strut unlocking electro-hydrostatic actuator of claim 1, wherein the piston cylinder is an asymmetric piston cylinder for shortening the axial length of the piston cylinder, and the extension cavity D and the retraction cavity F of the piston cylinder are communicated with the shuttle valve through damping holes. When the stay bar is in a locking state, the extension cavity D and the retraction cavity F of the piston rod are communicated, the pressure intensity of the two cavities is the same, the area of the extension cavity D is larger than that of the retraction cavity F, so the piston rod can be subjected to outward extension force of the extension cavity D, the piston rod is enabled to extend outwards under the acting force of a locking spring, the two ends of the piston cylinder are connected with the main body structure of the landing gear stay bar through the lug rings and the joint bearings, and the piston rod is driven to move when the main body structure of the stay bar contracts.
7. The undercarriage strut unlocking electro-hydrostatic actuator of claim 6, wherein the locking spring is in contact with the piston cylinder body at one end and the flange on the piston rod at the other end, the locking spring having a pre-compression amount that provides a combined force of the spring force and the asymmetric piston cylinder hydraulic force that provides the required locking force for the undercarriage strut unlocking electro-hydrostatic actuator.
8. The undercarriage strut unlocking electro-hydrostatic actuator according to claim 6, wherein the shuttle valve includes a normally closed oil inlet A, a normally open oil inlet B and an oil outlet C, the normally open oil inlet B of the shuttle valve is connected with the damping hole and leads to an extension cavity D of the piston cylinder and the energy accumulator; a normally closed oil inlet A of the shuttle valve is connected with the output end of the hydraulic pump 4; an oil outlet C of the shuttle valve is connected with a retraction cavity F of the piston cylinder, and the shuttle valve switches an oil path leading to the retraction cavity F of the piston cylinder through a normally closed oil inlet A, a normally open oil inlet B and the working state of the hydraulic pump.
9. The undercarriage strut unlocking electro-hydrostatic actuator of claim 6, wherein one end of the damping hole is connected to the extension cavity D of the piston cylinder, and the other end is connected to the retraction cavity F of the piston cylinder through a normally open oil inlet B of the shuttle valve.
10. A method of operating a landing gear strut unlock electro-hydrostatic actuator according to any of claims 1 to 9, comprising the steps of:
(1) Firstly, judging whether the undercarriage is ready to contract or not, if not, sending an unlocking instruction to a controller, at the moment, the controller, a motor driver, a motor and a hydraulic pump do not work, a shuttle valve keeps a normally closed oil inlet A in a closed state, under the action of an upper locking spring force, a piston rod of a piston cylinder extends out to reach a limit position, a strut rocker arm and a connecting rod cross a mechanism pole, so that an upper strut and a lower strut cannot be folded, and an undercarriage strut unlocking electro-hydrostatic actuator is in a locked state;
(2) If the undercarriage is ready to contract and an unlocking instruction is sent to the controller, the controller and the motor driver are powered on, then the controller judges whether the unlocking instruction is received, if the unlocking instruction is not received within a specified time, the motor is powered off, the shuttle valve keeps the normally closed oil inlet A in a closed state, the piston rod of the piston cylinder is still in a limit position at the moment, and the undercarriage strut unlocking electro-hydrostatic actuator is still in a locked state;
(3) If an unlocking instruction is received, the motor is electrified to drive the hydraulic pump to rotate, the normally closed oil inlet A of the shuttle valve is opened under the impact of hydraulic pressure, hydraulic oil flows into the retraction cavity F of the piston cylinder, so that the piston rod shaft retracts, at the moment, whether unlocking action is finished or not is judged through a displacement signal fed back by the position sensor, if the piston rod reaches a specified position and finishes the unlocking action, the motor is electrified, the valve core of the shuttle valve returns to the normally closed oil inlet A under the action of built-in spring force of the shuttle valve, the oil circuit of the extension cavity D and the retraction cavity F of the piston cylinder is switched to a communication state, the piston rod is located at a non-limit extension position and can be retracted/extended along with the folding of the undercarriage, and the undercarriage strut unlocks the electro-hydrostatic actuator to be in a follow-up state;
(4) If the displacement fed back by the piston rod position sensor does not reach the designated position, the motor keeps moving all the time, the hydraulic pump is driven to convey hydraulic oil to drive the piston rod to do contraction movement, and the undercarriage strut unlocking electro-hydrostatic actuator is in an unlocking state until the displacement stroke required by the unlocking action is completed.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211636424.8A CN115783250B (en) | 2022-12-19 | 2022-12-19 | Landing gear stay bar unlocking electro-hydrostatic actuator and working method |
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| CN202211636424.8A CN115783250B (en) | 2022-12-19 | 2022-12-19 | Landing gear stay bar unlocking electro-hydrostatic actuator and working method |
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| CN115783250B CN115783250B (en) | 2024-08-27 |
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5667697A (en) * | 1979-09-13 | 1981-06-06 | Messier Hispano Sa | Wheel device*which can be drawn in* of car* particularly* aircraft |
| CN112431817A (en) * | 2020-12-08 | 2021-03-02 | 四川凌峰航空液压机械有限公司 | Buffer device for controlling motion speed of actuating cylinder |
| CN215043641U (en) * | 2021-05-10 | 2021-12-07 | 四川凌峰航空液压机械有限公司 | Hydraulic retraction system for any position of undercarriage |
| KR20220047758A (en) * | 2019-08-07 | 2022-04-19 | 얜산 유니버시티 | Switchable vehicle suspension system for active and passive dual mode and method for switching the same |
-
2022
- 2022-12-19 CN CN202211636424.8A patent/CN115783250B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5667697A (en) * | 1979-09-13 | 1981-06-06 | Messier Hispano Sa | Wheel device*which can be drawn in* of car* particularly* aircraft |
| KR20220047758A (en) * | 2019-08-07 | 2022-04-19 | 얜산 유니버시티 | Switchable vehicle suspension system for active and passive dual mode and method for switching the same |
| CN112431817A (en) * | 2020-12-08 | 2021-03-02 | 四川凌峰航空液压机械有限公司 | Buffer device for controlling motion speed of actuating cylinder |
| CN215043641U (en) * | 2021-05-10 | 2021-12-07 | 四川凌峰航空液压机械有限公司 | Hydraulic retraction system for any position of undercarriage |
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| CN115783250B (en) | 2024-08-27 |
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