A landing gear retraction mechanism capable of stopping and adjusting the attitude

Abstract

A landing gear retraction mechanism capable of halting and adjusting its posture. The upper end of the vertical torsion bar is connected to the lower end of the gear connecting rod; the upper end of the gear connecting rod is connected to the gear. The upper end of the ball screw is connected to the lower end of the vertical torsion bar; the lower end of the ball screw is installed on the lower end block. A ball nut is sleeved on the ball screw. Buffer connection sleeves are respectively sleeved on the upper and lower ends of the buffer. Each buffer is slidably matched with two vertical guide rails. The wheel is connected to one end of the buffer piston rod, and there is a buffer at the other end of the buffer piston rod. When an aircraft equipped with the present invention loads and unloads goods, it can actively retract some of the landing gears to reduce the height of the cargo hold floor, thereby making the loading and unloading of goods more convenient, reducing the floor of the transport aircraft by at least more than 30% from the existing height, facilitating the loading and unloading of goods, saving structural space, and having the advantages of high transmission accuracy, high high-speed feeding efficiency, small heat generation, smooth movement, and reversibility of transmission, reducing the maintenance and operation costs.

Description

Technical Field

[0001] The invention relates to the technical field of landing gear design for transport aircraft, in particular to a landing gear retracting and extending mechanism capable of stopping and adjusting the posture. Background Art

[0002] The design of the landing gear of a transport aircraft is closely related to the height of the cargo hold floor from the ground. A lower height of the cargo hold floor from the ground is conducive to convenient and quick loading and unloading of cargo and shortening the ground turnover time of the aircraft.

[0003] In the invention with the publication number CN114810902A, a retractable aircraft landing gear buffer is disclosed. The hydraulic control system of the buffer includes a buffer hydraulic pipeline, a buffer hydraulic control valve, a buffer hydraulic oil pipe, a buffer hydraulic return pipe and a buffer hydraulic one-way valve; wherein the buffer hydraulic pipeline is used to fill and discharge oil to the buffer; the buffer hydraulic control valve is used to change the flow direction of the oil in the hydraulic pipeline; the buffer hydraulic oil pipe is used to input the hydraulic oil in the aircraft hydraulic system into the buffer hydraulic control system; the buffer hydraulic return pipe is used to input the hydraulic oil in the buffer hydraulic control system into the aircraft hydraulic system; the buffer hydraulic one-way valve is used to ensure that the oil flows in the buffer oil pipe in a specified direction. The buffer adjusts its height by filling and discharging oil to achieve the lowering and raising of the cargo hold floor height, a process also called squatting and canceling squatting. Although the buffer can also achieve the purpose of making the aircraft squat when parking, since this hydraulic squatting requires a complex hydraulic power system and a dedicated control system to cooperate, the overall design is often more complicated. In addition, due to the structural limitations of the buffer itself, the squatting stroke of the retractable aircraft landing gear buffer is very short.

[0004] On March 1, 2012, in DE102010039897 (A1), German Robert Mario proposed a retractable landing gear. The retractable landing gear has a wheel fixed on a steering knuckle, which is guided by the fuselage of an amphibious vehicle. The rotatably mounted pivot is firmly connected to the inside of the fuselage. The lockable joystick is set on the pivot inside the fuselage, so that the height of the wheel can be adjusted relative to the fuselage by the movement of the drive rod. The structure of the invention is simple, and its specific power system directly acts on the operating rod, but the rationality of the heavy load and the mechanism is not considered. That is, although the invention can also reduce the height of the fuselage, it cannot be used for medium and large transport aircraft.

[0005] Similar to the invention that can adjust the aircraft attitude on the ground by the movement of the landing gear mechanism, there is also a retractable shock strut for retractable landing gear disclosed in US2010096499 (A1). The invention is used for a retractable shock strut system for aircraft landing gear, with a retracting actuator, whose length can be moved to expand or retract the landing gear, including a retracting strut and a transmission device. The length of the retracting strut can be compressed so that it can be stored in the fuselage. The transmission device can communicate with the strut retractor in a closed fluid, and is used to transfer hydraulic fluid into and out of the strut retractor. When driven by an aircraft hydraulic system that is independent of any movement of the retracting actuator, the transfer device can drive the hydraulic fluid to retract toward the strut, thereby compressing or retracting the retracting strut to a partially compressed length. This invention also belongs to the hydraulic type of controlled squatting, and the shock strut is filled and drained by the hydraulic system to achieve the rise and fall of the height. When applied to large aircraft, the volume of the invention will also be huge, and the oil chamber of the retractable shock strut that can be used for adjustment will also increase exponentially in volume during the filling and draining time, which is not efficient for aircraft that pursue short loading and unloading.

[0006] Changsha Inbedi Electronic Technology Co., Ltd. disclosed an automatic locking mechanism for lowering the aircraft landing gear in its utility model patent with announcement number CN215922535U. The automatic locking mechanism for lowering the aircraft landing gear includes a support frame, which is characterized in that: a rotating wheel is rotatably connected inside the support frame, a connecting column is fixedly connected to an outer wall of the rotating wheel, a connecting column is fixedly connected to a connecting block, a wheel is rotatably connected to one side of the connecting block, a connecting rod is rotatably connected to the other side of the connecting block, a sliding block is rotatably connected to the sliding block, the sliding block is slidably connected to the support frame, and the sliding block is fixedly connected to a first electric telescopic rod, a mounting seat is fixedly connected to the top of the support frame, the mounting seat is fixedly connected to a second electric telescopic rod, the second electric telescopic rod is fixedly connected to a second limiting block, the second limiting block is fixedly connected to a first spring, the first spring is fixedly connected to a movable block, the upper and lower ends of the movable block are fixedly connected to baffles, both sides of the baffle are fixedly connected to square side plates, the square side plates are fixedly connected to second springs, the second springs are fixedly connected to clamping blocks, and the clamping blocks are clamped on the sliding block, the clamping blocks are rotatably connected to a rotating shaft, the rotating shaft is rotatably connected to the baffle, and the bottom of the rotating shaft is slidably connected to the support frame. Although this invention has detailed considerations on automatic locking, it is not designed or equipped with any buffering components. When used in engineering, each landing of an aircraft will be subjected to a huge impact, which may cause damage to the fuselage or landing gear structure. Summary of the invention

[0007] In order to make up for the shortcomings of the prior art such as large volume, small squatting distance, failure to take into account the buffering effect, and unsuitability for medium and large transport aircraft, the present invention proposes a landing gear retracting and extending mechanism capable of stopping and adjusting the posture.

[0008] The present invention includes a drive motor input shaft, a gearbox, a gear case, a vertical torsion bar, a ball screw, a back plate, a vertical guide rail, a buffer connection sleeve, a buffer, a wheel shaft connector, and a buffer piston rod; wherein: The gear case is a gear case, which is installed at the top of the back plate and connected to one end of the drive motor input shaft; a gearbox is installed at the other end of the drive motor input shaft. The upper end of the vertical torsion bar is connected to the lower end of the gear connecting rod; the upper end of the gear connecting rod is connected to the gear inside the gear case. The upper end of the ball screw is connected to the lower end of the vertical torsion bar; the lower end of the ball screw is installed on the lower stop block through a bearing; the middle part of the ball screw is fixed to the back plate through the back plate ball screw fixing lugs. A ball nut is sleeved on the ball screw. A buffer connection sleeve is sleeved on the upper end and the lower end of the buffer respectively, and the buffer is slidably matched with two vertical guide rails on the back plate through each of them. The wheel is connected to one end of the buffer piston rod through a wheel shaft connector, and the other end of the buffer piston rod is connected to the buffer.

[0009] The back plate includes a bottom plate, two side plates, and a lower stop block, and its cross-section is concave-shaped. The two side plates are two vertical guide rails respectively. There is a lower stop block at the lower end of the back plate; there is an installation hole for a bearing at the geometric center of the lower baffle. Three square solenoid valve limit holes are distributed along the length direction of the back plate on the bottom plate of the back plate, which are the solenoid valve upper position lock hole, the solenoid valve squat lock hole, and the solenoid valve lower position lock hole from top to bottom; the upper position lock hole is at the midpoint position of the vertical length of the back plate, the squat lock hole is 1100 mm below the upper position lock hole in the vertical direction, and the lower position lock hole is 390 mm below the squat lock hole in the vertical direction; there are solenoid valve installation grooves on both sides of the three solenoid valve limit holes, and the solenoid valve installation grooves extend along the length direction of the back plate. A bearing is also installed on the back plate, and the bearing is located 220 mm above the solenoid valve upper position lock hole.

[0010] The geometric centers of the three solenoid valve limit holes, the centers of the two bearings, and the center of the back plate ball screw fixing lugs are all located on the same vertical plane.

[0011] The solenoid valve mentioned is the overall component name composed of a solenoid valve body, a solenoid valve block and other electronic components. The present invention does not introduce and protect the electronic components therein. The solenoid valve body is in the shape of a square shell with lugs at the base, and the solenoid valve block can telescopically move therein. The inner cavity of the solenoid valve body is the card slot of the solenoid valve body. On the outer surfaces of both sides at the inner end of the solenoid valve body, there are connecting blocks respectively. During use, the electromagnetic block is embedded into the card slot of the solenoid valve body, and the electromagnetic block can move horizontally. The connecting blocks located on the outer surfaces of both sides of the solenoid valve body are respectively clamped in the solenoid valve mounting slots, and are fixedly connected to the solenoid valve connecting piece and the ball nut located on the inner surface of the bottom plate. The ball nut is sleeved on the ball screw and embedded in the solenoid valve connecting piece.

[0012] The inner diameter of the buffer connection sleeve is the same as the outer diameter of the buffer, and an interference fit is formed between the two. At the upper and lower ends of the outer circumferential surface of the buffer connection sleeve, there are radially protruding connection lugs respectively, and the ball screw holes on the two connection lugs are coaxial.

[0013] The ball nut connecting piece is plate-shaped and consists of a bottom plate and a pair of connecting plates. The pair of connecting plates are located at the edges of the two long sides of the inner surface of the bottom plate and are respectively perpendicular to the inner surface of the bottom plate. A card slot is formed between the pair of connecting plates, and there are U-shaped openings on the pair of connecting plates for cooperating with the ball screw. During use, the card slot is clamped on the solenoid valve connecting piece and the ball nut, and the ball screw is embedded into the U-shaped opening. The outer surface of the bottom plate is attached to the buffer connection sleeve. At the two short sides of the inner surface of the bottom plate, there are guide slots for cooperating with the vertical guide rails respectively.

[0014] The ball screw nut is sleeved on the ball screw, and balls are installed in the inner hole. On the outer circumferential surface at the upper end of the ball screw nut, there is a radially protruding boss for connecting the ball nut connecting piece and the buffer connection sleeve. A pair of bevel gear sets are assembled in the gearbox, and its function is to convert the horizontal movement output by the gearbox into the rotation of the vertical torsion bar.

[0015] The number of teeth of the input bevel gear of the gearbox: the number of teeth of the output bevel gear of the gearbox = 1:3; the input speed is 1070.5 r / min.

[0016] In the present invention, the power of the hydraulic motor is input into the transmission gearbox group and then transmitted to the gearbox. The function of the gearbox is to change the direction of power transmission. There is a hole at the bottom of the gearbox, and at the bottom of the large axial vertical bevel gear inside, there is a gear connecting rod, which is fixedly connected to the universal coupling. The vertical torsion bar is a straight bar, and both ends are fixedly connected to the universal coupling. One end is connected to the universal coupling on the gear connecting rod of the large bevel gear, and the other end is used to connect to the ball screw. The ball nut is sleeved on the ball screw, and a solenoid valve is fixed on the ball nut. When the ball screw rotates, it drives the ball nut on it to move up and down. The two gearboxes are fixedly connected to the fuselage by the housing and the frame.

[0017] In the present invention, the back plate is a rectangular plate made of high-strength alloy, fixed to the fuselage frame, and is provided with three solenoid valve block limiting holes, which are respectively distributed on the back plate and cooperate with the solenoid valve body to stop the ball screw nut. In addition, there is a convex lug on one side of the back plate surface. A bearing is assembled inside the lug to place the bearing at one end of the ball screw. There is also a locking bearing in the center of the stop block at the lower end of the back plate, which is also used to install the other end of the ball screw. A vertical solenoid valve installation groove is opened on the back plate for the earpiece of the solenoid valve body to pass through to form a sliding restraint. The vertical guide rails are fixed on both sides of the back plate, and guide grooves are opened on the inner mating surface. The ball screw nut is in the shape of a long sleeve, with a ball thread in the inner hole, sleeved on the ball screw, and there are open earpieces on both outer sides for connecting other accessories. The solenoid valve is fixed to the buffer connection sleeve through the solenoid valve connection piece, and the ball nut is fixed together with bolts. When the ball nut moves, it can drive the entire buffer to move up and down, thereby indirectly driving the wheel axle to move up and down. The solenoid valve connection piece consists of two pieces, in the shape of a steel T-shape; the buffer connection piece is in the shape of a round hoop, and the base has earpieces with bolt holes, which are fixed to the ball nut connection piece with bolts to fix the buffer, thereby indirectly driving the wheel axle; the ball nut connection piece is long and flat, with slider-shaped earpieces on both sides, used to be embedded in the vertical guide rail grooves. Each landing gear has two upper and lower ball nut connection pieces to provide restraint, and only releases the freedom of its own vertical up and down movement.

[0018] The buffer function module involved in this landing gear is the oil and gas buffer of a conventional aircraft landing gear, which is not required in the present invention.

[0019] Compared with the prior art, the advantages and beneficial effects of the present invention are as follows:

[0020] 1. When an aircraft equipped with the landing gear retraction and extension mechanism of the present invention is loading and unloading goods, it can actively retract some of the landing gears to reduce the height of the cargo hold floor, making it more convenient to load and unload goods. Through model simulation research and calculation, it is obtained that using this mechanism can reduce the floor of a transport aircraft by at least 30% or more from the existing height. After the height of the aircraft cargo hold floor is reduced, it is significantly more convenient for personnel to load and unload goods into and out of the cabin.

[0021] 2. Through the integrated design, the squatting function is incorporated into the retraction and extension mechanism, which realizes both the conventional retraction and extension function and the squatting posture adjustment on the ground. The landing gear squatting posture adjustment can be achieved without an additional squatting mechanism system, saving structural space.

[0022] 3. The locking mechanism of the landing gear retraction and extension mechanism of the present invention uses an electromagnetic valve locking mechanism, which has higher replaceability and easier maintenance compared with the traditional landing gear locking mechanism.

[0023] 4. The landing gear structure of the present invention uses a ball screw to act as the retraction and extension wheel and the squatting function. Compared with the conventional adjustment buffer type squatting landing gear, its squatting time is not greatly affected by the size of the landing gear itself, and the squatting stroke is mainly determined by the screw stroke, that is, the mechanical structure. The optimized squatting amount of the present invention is 390 mm, which is increased compared with the squatting amount of about 250 mm of the adjustment buffer type squatting landing gear.

[0024] 5. The landing gear structure of the present invention uses a ball screw as the retraction and extension wheel and the squatting mechanism. Compared with the conventional adjustment buffer type squatting landing gear, the mechanism using the ball screw pair for squatting has a full squatting range, small driving torque, high transmission efficiency, high precision, high stiffness, high reliability, good synchronization performance, and can achieve micro-feed. At the same time, the linkage between shafts is not rigidly connected, but a universal coupling is used, which has the characteristics of high transmission precision, high high-speed feed efficiency, small heat generation, and stable movement. Due to its advantages such as small frictional resistance and high reverse transmission efficiency, when applied to the landing gear, the maintenance and operation costs are correspondingly lower. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is the three-dimensional structural schematic diagram of the present invention.

[0026] Figure 2 a is Figure 1 the front view in the course direction, Figure 2 b is the rear view, Figure 2 c is the axonometric view after hiding the wheels.

[0027] Figure 3 is the schematic diagram of the backplane space structure in the landing gear retraction and extension mechanism with stoppable posture adjustment, where Figure 3 a is the three-dimensional schematic diagram of the backplane space, Figure 3 b is the front view of the backplane.

[0028] Figure 4 is the transmission function module of the landing gear retraction and extension mechanism with stoppable posture adjustment, where Figure 4 a is the three-dimensional schematic diagram of the transmission module space, Figure 4 b is the front view of the transmission module, Figure 4 c is Figure 4 the partial sectional view of part A in a, Figure 4 d isFigure 4 Partial sectional view of part B in b.

[0029] Figure 5 It is a sectional view of the component structure in the locking mechanism cooperating with the back plate.

[0030] Figure 6 It is an assembly relationship diagram of the solenoid valve locking mechanism and the ball nut, where Figure 6 a is the front view, Figure 6 b is the side view, Figure 6 c is the top view, Figure 6 d is the axonometric view.

[0031] Figure 7 It is an exploded view of the assembly of the solenoid valve locking mechanism, the buffer connection sleeve and the back plate.

[0032] Figure 8 It is a schematic diagram of the overall structure of the retractable mechanism that can stop and adjust the posture; where Figure 8 a is the front view, Figure 8 b is the rear view, Figure 8 c is the axonometric view.

[0033] Figure 9 It is a schematic diagram of the squatting, retracting and extending spatial postures of the landing gear mechanism that can stop and adjust the posture; where Figure 9 a is the posture diagram when the landing gear is locked at the lower lock, Figure 9 b is the posture diagram when the landing gear is locked at the squatting position lock, Figure 9 c is the posture diagram when the landing gear is retracted and locked at the upper lock.

[0034] Figure 10 It is a schematic diagram when the aircraft is loading after squatting for parking and posture adjustment.

[0035] In the figure: 1 - drive motor input shaft; 2 - gearbox; 4 - gear box; 5 - vertical torsion bar; 6 - ball screw; 7 - back plate; 8 - vertical guide rail; 9 - buffer connection sleeve; 10 - buffer; 11 - ball nut; 12 - ball nut connecting piece; 13 - solenoid valve body; 14 - solenoid valve block; 22 - bearing; 23 - universal coupling; 24 - wheel axle; 25 - wheel; 26 - bolt; 27 - nut; 29 - solenoid valve upper lock hole; 30 - solenoid valve squat lock hole; 31 - solenoid valve lower lock hole; 32 - lower stop block; 33 - solenoid valve installation groove; 34 - back plate ball screw fixing lug; 35 - bolt hole; 36 - solenoid valve connecting piece; 37 - gear connecting rod; 38 - wheel axle connecting piece; 39 - buffer piston rod; 40 - screw; 41 - small bolt and nut. Specific implementation mode

[0036] This embodiment is a landing gear retraction mechanism that can be stopped and its attitude adjusted, including a drive motor input shaft 1, a gearbox 2, a gearbox 4, a vertical torsion bar 5, a ball screw 6, a back plate 7, a vertical guide rail 8, a buffer connection sleeve 9, a buffer 10, a ball nut 11, a ball nut connection piece 12, a solenoid valve body 13, a solenoid valve block 14, a bearing 22, a universal coupling 23, a wheel axle 24, a wheel 25, a solenoid valve squat lock hole 30, a solenoid valve lower position lock hole 31, a lower end stop 32, a solenoid valve installation groove 33, a back plate ball screw fixing lug 34, a solenoid valve connection piece 36, a gear connection rod 37, and a wheel axle connection piece 38; among which:

[0037] The gearbox 4 is a 90° gearbox, which is installed at the top of the back plate 7 and connected to one end of the drive motor input shaft 1; a gearbox 2 is installed at the other end of the drive motor input shaft, and a manual crank interface is provided on the side of the gearbox 2. The upper end of the vertical torsion bar 5 is connected to the lower end of the gear connection rod 37 through a universal coupling 23; the upper end of the gear connection rod is connected to the gear inside the gearbox. The upper end of the ball screw 6 is connected to the lower end of the vertical torsion bar through a universal coupling 23; the lower end of the ball screw is installed on the lower end stop 32 through a bearing 22; the middle part of the ball screw is fixed to the back plate through a back plate ball screw fixing lug 34. A ball nut 11 is sleeved on the ball screw. The buffer 10 adopts the existing technology; a buffer connection sleeve 9 is sleeved on the upper end and the lower end of the buffer respectively, and the buffer is slidably matched with two vertical guide rails 8 on the back plate 7 through each of them. The wheel 25 is connected to one end of the buffer piston rod 39 through a wheel axle connection piece 38, and the other end of the buffer piston rod is connected to the buffer.

[0038] The back plate 7 includes a bottom plate, two side plates and a lower end stop 32, and its cross-section is concave-shaped, as Figure 3 shown. The two side plates are respectively two vertical guide rails 8. There is a lower end stop 32 at the lower end of the back plate; there is an installation hole for the bearing 22 at the geometric center of the lower end baffle. Three square solenoid valve limit holes are distributed along the length direction of the bottom plate of the back plate, which are the solenoid valve upper position lock hole 29, the solenoid valve squat lock hole 30 and the solenoid valve lower position lock hole 31 from top to bottom; the upper position lock hole 29 is at the midpoint position of the vertical length of the back plate, the squat lock hole 30 is 1100 mm below the upper position lock hole 29 in the vertical direction, and the lower position lock hole 31 is 390 mm below the squat lock hole in the vertical direction; there are solenoid valve installation grooves 33 on both sides of the three solenoid valve limit holes, and the solenoid valve installation groove extends along the length direction of the back plate. A bearing 22 is also installed on the back plate, and the bearing is located 220 mm above the solenoid valve upper position lock hole.

[0039] The geometric centers of the three solenoid valve limit holes, the centers of the two bearings 22, and the center of the backplane ball screw fixing lug 34 are all located on the same vertical plane.

[0040] The solenoid valve block 14 is installed on the outer surface of the middle bottom plate of the backplane 7 through the solenoid valve body 13. The outer shape of the solenoid valve body 13 is box-shaped; the inner cavity of the solenoid valve body is the card slot of the solenoid valve body. There are connecting blocks on the outer surfaces of both ends of the inner end of the solenoid valve body 13. During use, the solenoid valve block 14 is embedded in the card slot of the solenoid valve body 13, and the solenoid valve block 14 can move horizontally. The connecting blocks located on the outer surfaces of both sides of the solenoid valve body 13 are respectively clamped in the solenoid valve installation slots 33, and are fixedly connected by bolts 26 to the solenoid valve connecting piece 36 and the ball nut 11 located on the inner surface of the bottom plate. The ball nut is sleeved on the ball screw 6 and is embedded in the solenoid valve connecting piece.

[0041] The outer shape of the ball nut 11 is rectangular block-shaped, and there is a threaded hole matching the ball screw 6 at its geometric center; bolt holes are distributed at the four corners of the ball nut.

[0042] There are two buffer connection sleeves 9, both of which are sleeve-shaped. The inner diameter of the buffer connection sleeve is the same as the outer diameter of the buffer, and there is an interference fit between the two. There are radially protruding connecting lugs at the upper and lower ends of the outer circumferential surface of the buffer connection sleeve, and the ball screw holes on the two connecting lugs are coaxial. Bolt holes 35 for fixedly connecting the buffer connection sleeve 9 to the ball nut 11 and the ball nut connecting piece 12 are distributed on the two connecting lugs.

[0043] The ball screw 6 is manufactured by existing technology and is a 40cr precision ball screw. Its nominal diameter Dpw is 50mm, the nominal lead Ph is 10, the contact angle α is 45°, the steel ball diameter Dw is 6mm, and the rated static load of the ball screw is 7.2e+5N.

[0044] The ball nut connecting piece 12 is plate-shaped and consists of a bottom plate and a pair of connecting plates. The pair of connecting plates are located at the edges of the two long sides of the inner surface of the bottom plate and are respectively perpendicular to the inner surface of the bottom plate. A card slot is formed between the pair of connecting plates, and there is a U-shaped opening matching the ball screw 6 on the pair of connecting plates. During use, the card slot is clamped on the solenoid valve connecting piece 36 and the ball nut 11, and the ball screw is embedded in the U-shaped opening. The outer surface of the bottom plate is attached to the buffer connection sleeve 9. Guide grooves matching the vertical guide 8 are respectively provided at the two short sides of the inner surface of the bottom plate.

[0045] Before the transport plane is ready to load or unload, the torsion bar is driven by a motor. The driving force transmission direction is changed through the 90-degree bevel gearbox 4, driving the ball screw 6 to rotate, and then driving the ball nut 11 to move up and down along the ball screw, thereby driving the buffer 10 and the wheel axle 24 fixedly connected to the ball nut 11 to be lifted or lowered, so as to reduce the height of the transport plane floor and improve the loading and unloading efficiency. Since the buffer 10 and the wheel axle 24 are driven by the ball screw 6 to move vertically up and down, it can be used to lower the cargo hold floor for convenient loading and unloading when the plane stops for loading and unloading, and is used for the landing gear to retract and lower when the plane takes off and lands.

[0046] This embodiment has good integration. Since the solenoid valve lock mechanism is adopted in this embodiment, the landing gear has good integrity, which is manifested in that the retraction and extension position lock and the squat lock of the landing gear both realize their respective functions through a solenoid valve lock mechanism. Since the ball screw drive is adopted in this embodiment for the actuation of the landing gear, the landing gear has good integration, which is manifested in that a set of ball screw mechanisms realizes the two functions of retracting and extending the landing gear and squatting when the plane stops.

[0047] In this embodiment, the back plate 7 is used to be fixed to the fuselage frame. There are three solenoid valve block limit holes provided thereon, which are longitudinally distributed on the back plate 7, and are successively the upper position lock hole 29, the squat lock hole 30 and the lower position lock hole 31 from top to bottom, which cooperate with the solenoid valve body 13 to stop the ball screw nut 11. In addition, there is a convex lug 34 on one side of the surface of the back plate 7. A bearing 22 is assembled in the lug 34 for placing and assembling one end of the ball screw. A bearing is also provided at the center of the stop block 32 at the lower end of the back plate 7, which is also used to assemble the other end of the ball screw 6 to provide support for the ball screw 6. Shoulder treatments are performed at both ends of the ball screw 6, that is, both ends are cylindrical surfaces without threads and shoulders for the installation and positioning of the bearings; a vertical solenoid valve installation groove 33 is opened on the back plate for the earpiece of the solenoid valve body 13 to pass through and be fixed to the solenoid valve connecting piece 36 to form a sliding constraint; the vertical guide rails 8 are fixed at two side edges in the length direction of the back plate, as Figure 3 shown.

[0048] The ball screw nut 11 is sleeved on the ball screw 6, and balls are installed in the inner hole. There is a radially protruding boss on the outer circumferential surface at the upper end of the ball screw nut, which is used to connect the ball nut connecting piece 12 and the buffer connecting sleeve 9, as Figure 5 and Figure 6 shown. A pair of bevel gear sets at a 90-degree angle are assembled in the gearbox 4, and its function is to convert the horizontal movement output by the gearbox 2 into the rotation of the vertical torsion bar 5. There is a hole at the bottom of the gearbox 4. The bottom of the built-in axially vertical large bevel gear is fixedly provided with a gear connecting rod 37, which is fixedly connected to the universal coupling 23. The number of teeth of the input bevel gear of the gearbox: the number of teeth of the output bevel gear of the gearbox = 1:3, and the input speed is 1070.5 r / min.

[0049] The vertical torsion bar 5 is a straight bar, and both ends are fixedly connected to the universal coupling 23. One end is connected to the universal coupling on the large bevel gear connecting rod, and the other end is used to connect the ball screw 6. The universal coupling 23 is a standard part. The function of the wheel shaft connecting piece 38 is to fix the wheel shaft 24 to one end of the piston rod 39; the wheel shaft connecting piece adopts the existing technology.

[0050] The solenoid valve adopts the existing electromagnetic switch technology, but its main structural parts are independently designed, specifically including a solenoid valve body 13 and a solenoid valve block 14. This solenoid valve is fixed together with the buffer connecting sleeve 9 and the ball nut 11 by bolts. The solenoid valve body 13 is fixedly connected to the ball screw nut 11 by bolts through the lugs on its base. The solenoid valve block can expand and contract in the solenoid valve body. The buffer connecting sleeve 9 is fixedly connected to the ball nut connecting piece 12 by bolts and is used to connect the buffer 10, thereby indirectly driving the wheel 24 shaft. There are two ball nut connecting pieces 12. Through the cooperation of the ball nut connecting piece and the vertical guide rail 8, the up and down movement of the buffer 10 is realized, thereby driving the up and down displacement of the wheel 25 shaft. The solenoid valve block 14 is sleeved inside the solenoid valve body 13. When the solenoid valve block 14 extends, it will enter the upper solenoid valve locking hole 29 / the lower solenoid valve locking hole 30 / the lower lower solenoid valve locking hole 31 of the back plate 7, playing a role in locking the up and down movement trend of the landing gear; when the landing gear is lowered during the plane's preparation for landing, the solenoid valve moves with the ball nut 11 to the lower lower solenoid valve locking hole 31 and locks at this position; after the plane squats during parking, the solenoid valve moves with the ball nut 11 to the lower solenoid valve locking hole 30, the hydraulic motor stops rotating, and the solenoid valve locks at this position, which is the main means to prevent the landing gear from collapsing, as Figure 9 a and as Figure 9 b shows, the solenoid valve acts as the lower locking and squat locking functions during the retraction and extension process; when the solenoid valve is at the highest upper solenoid valve locking hole 29, as Figure 9 c shows, it can also be used as the landing gear retraction lock.

[0051] The retraction and extension and squatting of the landing gear are realized through the cooperation of the ball screw 6 and the solenoid valve. The power of the motor drives the ball screw 6 to rotate to lift the height of the buffer 10 and the wheel shaft 24 to achieve the purpose of lifting the landing gear; conversely, rotating the ball screw 6 in the opposite direction can lower the landing gear. If the plane is in a parked state, the lowering and restoration of the fuselage cargo hold are realized through the cooperation of the ball screw 6 and the solenoid valve.

[0052] The landing gear can adjust the height of the landing gear by rotating the ball screw to realize the lowering and raising of the cargo hold floor height. This process is also called the squatting and restoration process. In this process, the principle of how the ball screw is applied to the retraction and extension mechanism of this landing gear for actuation is introduced:

[0053] like Figure 4 As shown, the hydraulic drive motor rotates under the action of hydraulic pressure, driving the hydraulic motor to drive the gearbox input shaft to rotate, thereby transmitting the motion to the 90-degree gearbox through the gearbox output shaft, and the gearbox converts the rotation into the rotation of the vertical torsion bar. The upper end of the vertical torsion bar is connected to the protruding rod at the bottom of the gearbox through a universal coupling, and the lower end of the vertical torsion bar is connected to the upper end of the ball screw through a universal coupling. The function is to transmit the torque to the ball screw below through the universal coupling. The torsional power is transmitted from the vertical torsion bar, and the ball screw rotates in the bearing sleeve, and the rotation is converted into linear motion through the ball screw. The guide groove on the vertical guide restricts the ball nut connector to make it move up and down in the vertical direction. When the solenoid valve does not receive the locking signal, the limit hole of the solenoid valve block is not blocked, and the ball nut moves up and down accordingly under the rotation of the ball screw, which can smoothly realize the function of retracting and lowering the landing gear; the ball nut is fixedly connected to the landing gear buffer through the ball nut connector, thereby realizing the vertical retraction and extension movement of the landing gear wheel on the vertical guide rail. The overall assembly diagram of the retraction and extension mechanism is shown in Figure 8 shown.

[0054] Principle of landing gear retraction:

[0055] After the plane takes off, the solenoid valve at the lower lock hole receives the wheel retraction signal, and the solenoid valve block withdraws from the lower lock hole and shrinks into the solenoid valve body. At this time, the freedom of up and down movement of the ball nut fixed to the other side of the back plate with the solenoid valve is released; the motor starts to drive the ball screw to rotate continuously in the direction of upward wheel retraction, and the ball nut on the screw is lifted. When the solenoid valve moves upward to the upper lock hole on the back plate, the solenoid valve releases the solenoid valve block to extend from the magnetic valve body and protrude into the upper limit lock hole. Figure 9 As shown in c; under the obstruction of the valve block, the ball nut fixed to the solenoid valve body can no longer move, playing a role in locking the retracted landing gear, and the landing gear is retracted. When the aircraft lands, the principle of lowering the landing gear is the same, and the process is reversed;

[0056] The principle of squatting when the machine is stopped and adjusted on the ground:

[0057] When the aircraft is parked and ready to load or unload cargo, the initial position of the landing gear is that the solenoid valve is locked in the lower lock hole, and the drive motor is also in the parking state. Figure 9As shown in Fig. a; when a squatting signal is received, the solenoid valve block withdraws from the lower locking hole. At this time, the solenoid valve no longer bears the fuselage load of the landing gear. The fuselage load and the torque transmitted by the hydraulic motor to the ball screw cancel each other out, preventing the fuselage from sagging when the solenoid valve cancels the locking; immediately afterwards, the drive motor starts to rotate, the ball screw rotates in one direction, and the ball nut on the screw starts to move upward relative to its previous position on the screw. When it moves to the squatting locking hole, the hydraulic motor stops, and the ball screw immediately stops rotating in response. Subsequently, the solenoid valve extends and protrudes into the squatting locking hole, and the valve block is locked by the limit of the hole, and the landing gear stops adjusting its posture, as Figure 9 shown in Fig. b, the squatting is completed, and the squatting locking function of the landing gear is realized. The aircraft floor tilts at a certain angle α with the ground, as Figure 10 shown. After the loading and unloading are completed, the principle of the reset process is the same as above, but the process is reversed.

Claims

1. A landing gear retraction mechanism capable of stopping and adjusting the attitude, characterized in that, It includes a driving motor input shaft (1), a gearbox (2), a gear case (4), a vertical torsion bar (5), a ball screw (6), a back plate (7), a vertical guide rail (8), a buffer connection sleeve (9), a buffer (10), a wheel shaft connecting piece (38) and a buffer piston rod (39); wherein: The said gear case (4) is a gear case, installed at the top of the back plate (7) and connected to one end of the driving motor input shaft (1); A gearbox (2) is installed at the other end of the driving motor input shaft; The upper end of the said vertical torsion bar (5) is connected to the lower end of a gear connecting rod (37); The upper end of the gear connecting rod is connected to the gear inside the gear case; The upper end of the said ball screw (6) is connected to the lower end of the vertical torsion bar; The lower end of the ball screw is installed on a lower end block (32) through a bearing (22); The middle part of the ball screw is fixed on the back plate through a back plate ball screw fixing lug (34); A ball nut (11) is sleeved on the said ball screw; A buffer connection sleeve (9) is sleeved on the upper end and the lower end of the said buffer (10) respectively, and the buffer is in sliding fit with two vertical guide rails (8) on the said back plate through each buffer connection sleeve; A wheel (25) is connected to one end of the buffer piston rod (39) through a wheel shaft connecting piece (38), and the other end of the buffer piston rod is connected to the buffer; The said back plate (7) includes a bottom plate, two side plates and a lower end block (32), and its cross-section is concave-shaped; The two side plates are respectively two vertical guide rails (8); There is a lower end block (32) at the lower end of the back plate; There is an installation hole for the bearing (22) at the geometric center of the lower end block; Three square solenoid valve limit holes are distributed along the length direction of the back plate on the bottom plate of the back plate, which are the solenoid valve upper position lock hole (29), the solenoid valve squat lock hole (30) and the solenoid valve lower position lock hole (31) from top to bottom respectively; The said solenoid valve upper position lock hole (29) is at the midpoint position of the vertical length of the back plate, the solenoid valve squat lock hole (30) is vertically below the solenoid valve upper position lock hole (29), and the solenoid valve lower position lock hole (31) is vertically below the solenoid valve squat lock hole; There are solenoid valve installation grooves (33) on both sides of the three said solenoid valve limit holes, and the solenoid valve installation grooves extend along the length direction of the back plate; A bearing (22) is also installed on the back plate, and the bearing is located above the solenoid valve upper position lock hole.

2. The landing gear retraction mechanism capable of stopping and adjusting the attitude according to claim 1, characterized in that, The geometric centers of the three said solenoid valve limit holes, the centers of the two bearings (22) and the center of the back plate ball screw fixing lug (34) are all on the same vertical plane.

3. The retractable landing gear mechanism capable of stopping and adjusting the attitude according to claim 1, characterized in that, The inner cavity of the solenoid valve body (13) is the card slot of the solenoid valve body; on the outer surfaces of both sides of the inner end of the solenoid valve body, there are connecting blocks respectively; during use, the electromagnetic block is embedded into the card slot of the solenoid valve body, and the electromagnetic block can move horizontally; the connecting blocks on the outer surfaces of both sides of the solenoid valve body are respectively clamped in the solenoid valve mounting slots (33), and are fixedly connected to the solenoid valve connecting piece (36) and the ball nut (11) on the inner surface of the bottom plate; the ball nut is sleeved on the ball screw (6) and is embedded in the solenoid valve connecting piece.

4. The landing gear retraction mechanism capable of stopping and adjusting the attitude according to claim 1, characterized in that The inner diameter of the buffer connecting sleeve (9) is the same as the outer diameter of the buffer, and an interference fit is formed between the two; on the upper and lower ends of the outer circumferential surface of the buffer connecting sleeve, there are radially protruding connecting lugs respectively, and the ball screw holes on the two connecting lugs are coaxial.

5. The landing gear retraction mechanism capable of stopping and adjusting the attitude according to claim 1, characterized in that, The ball nut connecting piece (12) is plate-shaped and consists of a bottom plate and a pair of connecting plates; the pair of connecting plates are located at the edges of the two long sides of the inner surface of the bottom plate and are respectively perpendicular to the inner surface of the bottom plate; a card slot is formed between the pair of connecting plates, and there is a U-shaped opening on the pair of connecting plates that cooperates with the ball screw (6); during use, the card slot is clamped on the solenoid valve connecting piece (36) and the ball nut (11), and the ball screw is embedded into the U-shaped opening; the outer surface of the bottom plate is attached to the buffer connecting sleeve (9); on the two short sides of the inner surface of the bottom plate, there are guide grooves that cooperate with the vertical guide rails (8).

6. The landing gear retraction mechanism capable of stopping and adjusting the attitude according to claim 1, characterized in that, The ball nut (11) is sleeved on the ball screw (6), and balls are installed in the inner hole; on the outer circumferential surface of the upper end of the ball nut, there is a radially protruding boss for connecting the ball nut connecting piece (12) and the buffer connecting sleeve (9); a pair of bevel gear sets are assembled in the gearbox (4), and their function is to convert the horizontal movement output by the gearbox (2) into the rotation of the vertical torsion bar (5).

7. The landing gear retraction mechanism capable of stopping and adjusting the attitude according to claim 6, characterized in that, The number of teeth of the input bevel gear of the gearbox: the number of teeth of the output bevel gear of the gearbox = 1:3; the input speed is 1070.5 r / min.

Images