Buffer device for controlling the movement speed of the actuator

Abstract

The invention discloses a buffer device for controlling the movement speed of an actuator cylinder, which can improve the reliability of the locking device mechanism. The invention is achieved through the following technical scheme: an upper locking chamber is connected to a damping tube, and a flow-cutting annular groove is formed on the circumference of a sliding section of the damping tube; when the piston rod extends downward, the hydraulic oil enters the blind hole chamber of the piston rod along the damping tube, and after the blind hole chamber is filled with the hydraulic oil, the hydraulic oil slowly flows upward along the flow-cutting annular groove on the damping tube into the upper locking chamber, and the hydraulic pressure in the upper locking chamber slowly increases, and the piston rod is pushed to move under the action of the hydraulic pressure; when the piston rod retracts, the pressure in the unlocking chamber squeezes the piston rod, and the piston rod squeezes the hydraulic oil in the upper locking chamber, and the pressure in the upper locking chamber increases, and the hydraulic oil slowly flows from the upper locking chamber along the flow-cutting annular groove of the damping tube into the blind hole chamber of the piston rod, and the hydraulic oil in the unlocking chamber decreases, and the piston rod slowly slides along the damping tube; the liquid flow generates a damping force through the gap between the inner wall of the blind hole and the damping tube, and the damping force controls the movement speed of the piston rod, thereby realizing the buffering of the actuator cylinder.

Description

Technical Field

[0001] The invention relates to a buffer device for controlling the movement speed of an unlocking actuator cylinder of a hatch upper lock. Background Art

[0002] Modern aircraft landing gear retraction and extension systems generally use hydraulics as the normal retraction and extension power source, and use hydraulics, cooling air or electricity as the backup emergency power source. Whether the landing gear retraction and extension system can work properly directly affects the safety of the aircraft and passengers. The commonly used typical hydraulically powered landing gear retraction and extension system actuator cylinder consists of a selection valve, a retraction lock, a lowering lock, a sequence valve, a pipeline and some hydraulic accessories. These accessories are connected to each other to ensure the sequential movement of the landing gear and the cabin door. Since the sequence valve is closed, the pressure oil cannot flow into the cabin door actuator cylinder at this time, so the cabin door cannot be closed. Most of the actuator cylinders used in the aircraft hydraulic system retraction and extension part are simple, and certain hydraulic control mechanisms are required to be reliably fixed in the extreme position in specific parts. For example, after the landing gear is lowered, the actuator cylinder should become a rigid strut to bear the external load transmitted by the landing gear, so a mechanical locking device is provided inside the aircraft landing gear actuator cylinder. The landing gear upper lock, the normal unlocking piston and the emergency unlocking piston and their sealing rings are screwed together in the inner cavity of the housing and the plug cover, the lock hook and the manual unlocking rocker arm are installed on the housing through the bolt shaft, and the lock hook is maintained by a torsion spring installed at its rotating shaft. The hook and the guide are connected to the housing through bolts, and the hook is installed with a torsion spring to keep the hook in the unlocked position when the landing gear is not retracted; the manual unlocking rocker arm is fixed to the positioning pin on the housing through a retaining spring; the lock housing is provided with a normal unlocking oil inlet nozzle, an emergency unlocking oil inlet nozzle, and a return oil nozzle to provide supply and return oil interfaces; the pressure oil enters the three lowering lock actuator cylinders, the lowering lock opens, and the landing gear begins to retract. The front landing gear is retracted first and the retraction lock is locked because its actuator cylinder is small in size. In addition, because the front landing gear door is operated separately by the front landing gear linkage, the door is also closed; at the same time, the main landing gear is still in the retraction action, and the liquid at the lower end of each main landing gear actuator cylinder is squeezed out. At this time, the oil flows unimpeded through the one-way limiting valve, presses the sequence valve to open, flows through the landing gear selector valve and enters the return oil pipeline of the hydraulic system; then, when the main landing gear reaches the fully retracted position and the retraction lock is locked, the connecting rod of the transmission mechanism pushes the actuator rod of the sequence valve, opens the valve in the sequence valve and allows the pressure oil to enter the door actuator cylinder and close the landing gear door. On the main landing gear lock actuator, pressure will be provided to retract the piston rod. When the landing gear reaches the retracted position, the roller (locking ring) on ​​the strut hits the lock hook and enters the locked position to lock the landing gear. The pressure applied to the front landing gear lock actuator to start the retraction cycle also locks the front landing gear in the retracted and locked position. Before the wheels enter the wheel well area, the hydraulic pressure from the retraction pipe is also supplied to the two brake metering valves to stop the rotation of the wheels (brake). When the landing gear lowering control handle is placed in the "DOWN" position, the hydraulic pressure in the selector valve is transferred from P to the lowering pipe C1. The hydraulic pressure enters the lowering end of the landing gear retraction and extension actuator, the unlocking end of the upper locking actuator, the locking end of the lower locking actuator, and enters the landing gear lock actuator through the landing gear hydraulic assembly.Although this locking device can solve the problem of reliable locking, the inner cavity shape of the piston, the main component of the locking device, is very complex. The huge impact load during the retraction and extension process of the aircraft landing gear will cause the locking to fail. Therefore, it cannot meet the high reliability requirements of the aircraft. The return oil of the upper end of the landing gear retraction and extension cylinder is limited by the flow limiter in the hydraulic assembly. The limiting effect and the movement of the piston in the pressure transmission cylinder instantly cause the pressure to be transmitted from the lower end of the retraction and extension cylinder to the upper end, causing the landing gear to be retracted instantly due to the difference in piston area. This instantaneous effect is conducive to the lock actuator to retract, lock and unlock the landing gear. When the pressure transmission cylinder moves to the end, the pressure at the upper end of the retraction and extension actuator drops, and the landing gear is lowered in a normal manner. When the landing gear reaches the fully extended and lowered position, the lock actuator forces the lock strut to enter the neutral position to lock the landing gear. When the oil pressure enters the retracting chamber of the actuator to unlock, the area of ​​the piston oil pressure is relatively small, so the unlocking pressure is slightly higher than the locking pressure; the piston stroke must meet the regulations so that the retaining ring can be accurately in the locked position after the piston rod is extended; the movable clearance after the retaining ring enters the lock groove must not exceed the regulations, so as to avoid the impact force between the retaining ring and the lock groove being too large during operation and disengaging. The reciprocating motion of the piston rod fills the actuator with oil to open the mechanical lock, and a thrust of 7000k is applied to the piston rod in the upward direction for 1 minute. The piston rod must not retract. Excessive compression of the piston rod is usually caused by the hydraulic lock not being sealed and the oil leakage in the lowering chamber. The upper door lock installed in the aircraft landing gear compartment has limited space. Due to the small volume of the unlocking actuator pressure chamber, the hydraulic medium flow rate that can be provided on the aircraft is large, the piston rod moves fast, and the impact energy is large. It is difficult to meet the requirements of both strength stiffness and fatigue while achieving product lightweight and maintenance-free requirements.

[0003] The landing gear retracting and extending actuator is a kind of landing gear locking, retracting and extending, and bearing functions. The landing gear retracting and extending actuator is mainly composed of a multifunctional integrated hydraulic actuator of a piston body. The retracting and extending actuator is composed of a landing rod, an outer cylinder, a built-in upper lock, a hydraulic lock, a sensor, etc. The locking and bearing device of the inner frame in the lowered position and the upper lock of the locking device in the retracted position are mainly composed of a spring, a floating piston rod, a locking claw, a sliding sleeve, a setting, a trigger device for the locking signal of the landing gear retracted to the position, and also a pin, a reset spring, etc. At present, the normal order of lowering the landing gear of most civil aircraft is: (open the cabin door lock) open the cabin door, open the upper lock, release the landing gear lock, and close the cabin door (lock the cabin door lock). The machine-controlled sequential retracting and extending system uses a machine-controlled sequence valve (i.e., a machine-controlled one-way valve) to control the working order of the actuator. The existing hydraulic / pneumatic actuator position locking mostly adopts the form of "floating piston + steel ball". When the upper locking is performed, the position of the steel ball is limited by the armature, and the piston is limited by the steel ball and cannot be ejected, thus realizing the upper locking. When unlocking, the electromagnet is energized to attract the armature, loosen the steel ball, and eject the piston 28. The lower locking is achieved by using a spring, a floating piston 26 and a steel ball. The disadvantages of this locking technology are that the locking force is relatively small; the unlocking force required is relatively large; the steel ball and the armature are easily stuck, and the reliability is not high. The actuator structure generally consists of an outer cylinder, a piston rod, a piston, an end cover, a buffer device, etc. The buffering forms of the actuator are mainly two types: adding a rubber buffer pad and a hydraulic shock absorbing device. The main disadvantage of the rubber pad buffer is that the violent impact force and the heat generated are quite severe tests on the bonding force between the rubber pad and the piston. Over time, the rubber pad is easy to fall off or age, which affects the reliable locking of the locking mechanism. The hydraulic shock absorbing device separates the left chamber from the right chamber through the piston and the seal on the piston. Generally, a throttling hole is set at the right end. The buffering effect of the throttling hole is realized by the throttling hole set on the cylinder sleeve. Generally, a boss structure is set on the piston of the cylinder. When the piston moves to the right and enters the buffer stroke, the oil flows out from the oil port without throttling. When it continues to move to the left end and enters the buffer structure cavity, the boss enters the groove of the end cover. The oil in the back pressure cavity cannot flow freely from the unthrottled oil hole channel and is blocked, forcing the oil in the back pressure cavity to be discharged from an adjustable throttling hole. The main shortcomings of the hydraulic shock absorbing device are: when the structural size or quality index requirements are relatively strict, the throttling setting structure design at the left end is more complicated, and it is generally difficult to meet the structural requirements; in order to achieve a good buffering effect, oil will be added at the right end for damping, and there will be two media in the whole system, and an accumulator equivalent to storing hydraulic media needs to be designed, which is difficult to control the whole system.The buffer device of the prior art includes a spacer, a buffer and a spring which are sequentially installed in the mounting hole in the direction from the opening end of the mounting hole to the bottom end of the mounting hole. One end of the spring is connected to the bottom end of the mounting hole, and the other end of the spring is connected to the buffer. The spacer is fixed in the mounting hole through a connecting mechanism. The spacer and the buffer are respectively provided with a spacer vent and a buffer vent along the axial direction of the piston rod, and the inner wall of the mounting hole corresponding to the spring is provided with a piston rod vent leading to the cylinder body. The disadvantage of this device is that it cannot reduce the impact energy of the mechanical structure. When the actuator is retracted from the middle position of the full stroke, it will get stuck and cannot be unlocked and lowered. Because there is an inertial impact force when the screw nut moves from motion to rest, a bite force similar to a thread will be generated between the screw nut and the sleeve, resulting in a larger torque requirement during startup. When the lowering action is started again, if the motor starting torque is small, it is not enough to overcome the friction torque generated by the bite force, resulting in the failure of the actuator to extend. Summary of the invention

[0004] The task of the present invention is to provide a buffer device that can improve the reliability of the locking device mechanism, meet the movement speed of the deceleration mechanism integrated in the upper lock unlocking actuator, reduce the impact energy of the mechanical structure, and control the movement speed of the actuator with a maintenance-free function.

[0005] The technical solution adopted by the present invention to solve its technical problems is: a buffer device for controlling the movement speed of an actuator cylinder, comprising: a piston rod 1 integrated in an outer cylinder 3 of the actuator cylinder, assembled in an upper locking chamber, and the piston rod 1 is provided with a blind hole chamber, characterized in that: a damping tube 2 is provided on the upper locking chamber, which is sealed in an upper locking nozzle of the actuator cylinder through an O-ring 4 and connected to the oil flow path of the locking nozzle; a cut-off ring groove 5 is provided on the circumference of the sliding section of the damping tube 2, which moves along the direction of the blind hole chamber 7 and adjusts the movement spacing between the damping tube 2 and the piston rod 1; when the piston rod 1 extends downward, the hydraulic oil enters the damping tube 2 from the upper locking nozzle 9, and enters the blind hole chamber of the piston rod 1 along the damping tube 2 7. After the blind hole cavity 7 is filled with hydraulic oil, it slowly flows upward along the intercepting ring groove 5 on the damping tube 2 into the upper locking cavity. The liquid pressure in the upper locking cavity slowly increases, and under the action of the liquid pressure, the piston rod 1 is pushed to move; when the piston rod retracts, the pressure in the unlocking cavity 6 squeezes the piston rod 1, and the piston rod 1 squeezes the hydraulic oil in the upper locking cavity. The pressure in the upper locking cavity increases, and the hydraulic oil slowly flows from the upper locking cavity 6 along the intercepting ring groove 5 of the damping tube 2 into the blind hole cavity of the piston rod 1. The hydraulic oil in the unlocking cavity 6 decreases, and the piston rod 1 slowly slides along the damping tube 2; the liquid flows through the gap between the inner wall of the blind hole and the damping tube (2) to generate a damping force, and the damping force controls the movement speed of the piston rod 1, thereby achieving the buffering of the actuator and reducing the mechanical impact energy.

[0006] Compared with the prior art, the present invention has the following beneficial effects:

[0007] The present invention adopts a piston rod 1 integrated in the locking chamber of the outer cylinder 3 of the actuator. The piston rod 1 with a blind hole cavity slides on the damping tube 2. The damping tube adjusts the flow rate of the oil in the locking chamber and the blind hole cavity of the actuator in the form of annular groove interception to achieve the control of the speed of the piston rod damping movement. The hydraulic / pneumatic actuator speed control can be achieved, the movement process is stable, the structure is simple, and the reliability is high. The impact is mitigated, the severity of the operating conditions of the upper lock parts of the actuator is reduced, the reliability of the locking device mechanism is improved, and at the same time, due to the small inertial impact force, the noise caused by the impact is reduced, and the stealth performance of the aircraft is improved.

[0008] During the reciprocating sliding of the piston rod of the present invention in the working cycle, a damping force is generated when the liquid flows through the blind hole of the piston rod and the tiny gap between the damping tube. The damping force controls the movement speed of the piston rod 1 to achieve actuator buffering and reduce the mechanical impact energy. The annular groove interception adopts a whole circle of circular gaps, and impurities in the oil are not easy to clog the annular groove gaps. The method of reducing the hydraulic flow by annular gap interception can achieve the purpose of slowing down the movement speed of the mechanism, reducing the impact energy of the mechanical structure, and eliminating maintenance. It also has the ability of self-cleaning during the working cycle, and there will be no jamming failure or jamming problem, so the maintenance-free requirement is achieved. By adopting the annular gap interception solution, the reliable operation with the functions of slowing down the movement speed of the mechanism, reducing the impact energy of the mechanical structure, and eliminating maintenance is guaranteed under the requirements of lightweight design. In the device BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 is a cross-sectional view of a buffer device for controlling the movement speed of an actuator cylinder according to the present invention;

[0010] Figure 2 yes Figure 1 The relationship between the locking time, unlocking time and speed curve of the damping tube ring groove size.

[0011] In the figure: 1 piston rod, 2 damping tube, 3 outer cylinder of actuator, 4 "O" sealing ring, 5 intercepting ring groove, 6 locking chamber, 7 blind hole chamber, 8 unlocking chamber, 9 locking nozzle.

[0012] The present invention is further described below in conjunction with the accompanying drawings and embodiments, but the present invention is not limited to the scope of the embodiments described. All these concepts should be regarded as the content disclosed by the present technology and the protection scope of the present invention. DETAILED DESCRIPTION

[0013] See also Figure 1In the preferred embodiment described below, a buffer device for controlling the movement speed of an actuator cylinder comprises: a piston rod 1 integrated in an outer cylinder 3 of the actuator cylinder and assembled in an upper locking chamber 6, and the piston rod 1 is provided with a blind hole chamber 7, characterized in that: a damping tube 2 is provided on the upper locking chamber 6, which is sealed in an upper locking nozzle of the actuator cylinder through an O-ring 4 and connected to the oil flow path of the locking nozzle; a cut-off ring groove 5 is provided on the circumference of the sliding section of the damping tube 2, which moves along the direction of the blind hole chamber 7 and adjusts the movement spacing between the damping tube 2 and the piston rod 1; when the piston rod 1 extends downward, the hydraulic oil enters the damping tube 2 from the upper locking nozzle 9, and enters the blind hole chamber 7 of the piston rod 1 along the damping tube 2. After the blind hole cavity 7 is filled with hydraulic oil, it slowly flows into the upper locking cavity along the intercepting ring groove 5 on the damping tube 2, and the liquid pressure in the upper locking cavity slowly increases. Under the action of the liquid pressure, the piston rod 1 is pushed to move; when the piston rod retracts, the pressure in the unlocking cavity 6 squeezes the piston rod 1, and the piston rod 1 squeezes the hydraulic oil in the upper locking cavity. The pressure in the upper locking cavity increases, and the hydraulic oil slowly flows from the upper locking cavity 6 along the intercepting ring groove 5 of the damping tube 2 into the blind hole cavity of the piston rod 1. The hydraulic oil in the unlocking cavity 6 decreases, and the piston rod 1 slowly slides along the damping tube 2; the liquid flow generates a damping force through the gap between the inner wall of the blind hole and the damping tube 2, and the damping force controls the movement speed of the piston rod 1 to achieve actuator buffering and reduce mechanical impact energy.

[0014] The special ring groove on the damping tube plays the role of adjusting the damping force at different temperatures.

[0015] When the aircraft needs to execute the locking command, the avionics system sends a retracting command to the actuator, and the hydraulic supply locking device unlocks the actuator locking nozzle 9. The hydraulic oil flows into the damping tube 2, and flows into the locking chamber 6 through the narrow gap between the cut-off ring groove 5 on the piston rod 1 and the wall of the blind hole chamber 7. The actuator is retracted to the upper position and locked. Since the ring groove gap of the cut-off ring groove 5 is very narrow, the volume of the hydraulic oil flowing through is suddenly reduced, and the movement speed of the piston rod 1 reduces the impact energy of the mechanical structure, and it is locked in the retracted position. Similarly, when the landing gear is lowered, there is no problem in unlocking. When the aircraft needs to execute the unlocking command, the avionics system sends a lowering command to the actuator, and then supplies pressure to the locking device to unlock the locking nozzle of the actuator to unlock it, pushing the rodless cavity of the actuator to cause the upper lock locking device to move. The system hydraulic oil flows into the unlocking cavity under the locking nozzle, pushing the piston rod 1. The piston rod 1 squeezes the hydraulic oil in the upper locking cavity and slowly flows into the blind hole cavity of the piston rod 1 along the annular groove of the damping tube 2. The hydraulic oil in the unlocking cavity is reduced, and the piston rod 1 slides slowly along the damping tube 2. Since the busbar gap of the intercepting annular groove 5 that flows into the damping tube 2 is very narrow, the volume of the hydraulic oil flowing through is suddenly reduced, and the damping force is large. The damping force slows down the movement speed of the piston rod 1, and the upper lock of the actuator is opened, reducing the mechanical impact energy.

[0016] The speed of the piston rod 1 is determined by the gap size of the damping tube 2 intercepting ring groove 5 ring groove spacing section. The smaller the gap of the ring groove spacing section, the slower the piston rod moves, the longer the unlocking time of the locking device, and the smaller the impact. The relationship between the gap size of the groove spacing section and the speed of the unlocking / locking time is verified by experiments. Figure 2 As shown in the figure, the opening / locking test is repeated many times and the movement speed of the actuator is inversely proportional to the gap size of the ring groove spacing section, which is consistent with the theory. The above test shows that this structure can play a good buffering role in actual work. Therefore, the opening / locking speed of the locking device can be adjusted by controlling the gap size of the groove spacing section.

[0017] The scope of the present invention is not limited to the specific technical solutions described. Various modifications to the above-mentioned embodiments will be obvious to those skilled in the art. The general principles defined in the present invention can be implemented in other embodiments without departing from the spirit or scope of the present invention. Any technical solution obtained by replacing the technical elements in the specific technical solutions described with the same or equivalent or any technical solution that can be obtained by those skilled in the art without creative work on the basis of the specific technical solutions described shall be deemed to fall within the scope of protection of the present invention.

Claims

1. A buffer device for controlling the movement speed of an actuator, comprising: A piston rod (1) is integrated into an outer cylinder (3) of an actuator cylinder and assembled in an upper locking chamber (6), and the piston rod (1) is provided with a blind hole chamber (7), characterized in that: the upper locking chamber (6) is provided with a damping tube (2) which is sealed in an upper locking nozzle (9) of the actuator cylinder through an O-ring (4) and is connected to the oil flow path of the upper locking nozzle (9); a cut-off ring groove (5) is formed on the circumference of the sliding section of the damping tube (2) and moves along the direction of the blind hole chamber (7) to adjust the movement distance between the damping tube (2) and the piston rod (1); when the piston rod (1) extends downward, hydraulic oil enters the damping tube (2) from the upper locking nozzle (9), and enters the blind hole chamber (7) of the piston rod (1) along the damping tube (2); after the blind hole chamber (7) is filled with hydraulic oil, the hydraulic oil flows toward the damping tube (2). The hydraulic oil in the upper locking chamber (6) slowly flows along the intercepting ring groove (5) on the damping tube (2), and the hydraulic pressure in the upper locking chamber slowly increases. Under the action of the hydraulic pressure, the piston rod (1) is pushed to move. When the piston rod retracts, the hydraulic pressure in the unlocking chamber (8) squeezes the piston rod (1), and the piston rod (1) squeezes the hydraulic oil in the upper locking chamber (6). The pressure in the upper locking chamber (6) increases, and the hydraulic oil slowly flows from the upper locking chamber (6) along the intercepting ring groove (5) of the damping tube (2) into the blind hole chamber (7) of the piston rod (1). The hydraulic oil in the unlocking chamber (8) decreases, and the piston rod (1) slowly slides along the damping tube (2). The hydraulic oil generates a damping force through the gap between the inner wall of the blind hole and the damping tube (2). The damping force controls the movement speed of the piston rod (1), thereby achieving actuator buffering and reducing mechanical impact energy.

2. The buffer device for controlling the movement speed of the actuator according to claim 1, characterized in that: The intercepting annular groove (5) on the damping tube (2) plays a role in adjusting the magnitude of the damping force when the temperature is different.

3. The buffer device for controlling the movement speed of the actuator according to claim 1, characterized in that: When the aircraft needs to execute a locking command, the avionics system sends a retracting command to the actuator cylinder, supplies hydraulic oil to the locking nozzle (9) of the actuator cylinder, and the hydraulic oil flows into the damping tube (2), and flows into the locking chamber (6) through the narrow gap between the cut-off ring groove (5) on the piston rod (1) and the wall of the blind hole chamber (7). The actuator cylinder is manually raised and locked. Since the ring groove of the cut-off ring groove (5) is very narrow, the volume of the hydraulic oil flowing through is suddenly reduced, the movement speed of the piston rod (1) is reduced, and the mechanical impact energy is reduced, and it is locked in the manual position.

4. The buffer device for controlling the movement speed of the actuator according to claim 1, characterized in that: When the aircraft needs to execute the unlocking command, the avionics system sends a lowering command to the actuator cylinder, and then supplies pressure to the locking device to unlock the locking nozzle (9) of the actuator cylinder, pushing the rodless cavity of the actuator cylinder to cause the upper lock locking device to move, and the hydraulic oil flows into the unlocking cavity (8) below the upper lock nozzle, pushing the piston rod (1). The piston rod (1) squeezes the hydraulic oil in the upper lock cavity (6) and slowly flows into the blind hole cavity (7) of the piston rod (1) along the gap of the intercepting ring groove (5) of the damping tube (2). The hydraulic oil in the unlocking cavity (8) is reduced, and the piston rod (1) slowly slides along the damping tube (2). Since the gap of the intercepting ring groove (5) is very narrow, the volume of the hydraulic oil flowing through is suddenly reduced, and the damping force is large. The damping force slows down the movement speed of the piston rod (1), and the upper lock of the actuator cylinder is opened, reducing the mechanical impact energy.

5. The buffer device for controlling the movement speed of the actuator according to claim 1, characterized in that: The speed of the piston rod (1) is determined by the gap size of the annular groove spacing section of the intercepting annular groove (5) of the damping tube (2).

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