Landing legs of the aircraft

Abstract

To provide a reusable landing gear for a flight vehicle.SOLUTION: A landing gear 2 for a flight vehicle 1 is used during landing. The landing gear 2 for the flight vehicle 1 comprises: a first cylinder structure 3A with an upper end rollably coupled to the flight vehicle 1; and a second cylinder structure with a lower end contactable with the ground, configured to be relatively movable in an axial direction along a reference axis CL with respect to the first cylinder structure 3A, and configured to be relatively rotatable about the reference axis CL with respect to the first cylinder structure 3A. The first cylinder structure 3A and the second cylinder structure 3B switch the landing gear 2 between a stowed state and a released state by means of the relative movement and the relative rotation.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a landing gear of an air vehicle. [Background technology]

[0002] Conventionally, landing gear for an aircraft used when landing has been known. For example, Patent Document 1 discloses a landing gear for an aircraft that has a structure that allows it to land regardless of the condition of the landing site. The landing gear for this aircraft has a honeycomb-shaped core portion at the bottom of the aircraft, which has cell walls and a plurality of cell holes surrounded by the cell walls. The core portion has shock-absorbing holes that are larger in diameter than the cell holes and extend in the same direction as the cell holes. The honeycomb-shaped core portion and the shock-absorbing holes allow it to absorb collision energy when the aircraft lands. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6792385 Summary of the Invention [Problem to be solved by the invention]

[0004] However, because the core is honeycomb-shaped, the landing gear deforms every time the aircraft lands. This means that the landing gear needs to be manufactured and replaced every time the aircraft flies, increasing the running costs of flying the aircraft. Furthermore, since the landing gear needs to be disposed of after use, costs are also incurred to consider the environmental impact of disposal. Therefore, there is a demand for reusable landing gear for aircraft.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a reusable landing gear for an aircraft. [Means for solving the problem]

[0006] (1) A landing leg (e.g., landing leg 2 in the embodiments) of an aircraft (e.g., aircraft 1 in the embodiments) according to one aspect of the present invention is a landing leg of the aircraft used when landing, and comprises a first cylinder structure (e.g., first cylinder structure 3A in the embodiments) whose upper end is rotatably connected to the aircraft, and a second cylinder structure (e.g., second cylinder structure 3B in the embodiments) whose lower end can contact the ground, is configured to be movable relative to the first cylinder structure in an axial direction along a reference axis, and is configured to be rotatable relative to the first cylinder structure around the reference axis, and the first cylinder structure and the second cylinder structure switch the landing leg between a stored state and a deployed state by the relative movement and relative rotation.

[0007] (2) In one aspect of the present invention, the first cylinder structure may include an upper cylinder (e.g., upper cylinder 20 in the embodiment) whose upper end is rotatably connected to the aircraft, and a rotation mechanism (e.g., rotation mechanism 40 in the embodiment) provided on the upper cylinder and rotatable around the reference axis, and the second cylinder structure may include a lower cylinder (e.g., lower cylinder 30 in the embodiment) whose lower end is capable of contacting the ground and which is movable in the axial direction relative to the upper cylinder, and a guide structure (e.g., guide structure 50 in the embodiment) provided on the lower cylinder to guide the rotation of the rotation mechanism around the reference axis and the movement in the axial direction.

[0008] (3) In one aspect of the present invention, the rotation mechanism may alternately rotate and move relative to the guide structure in accordance with the axial movement of the lower cylinder, thereby alternately establishing a retracted state and an extended state of the landing gear.

[0009] (4) In one aspect of the present invention, the lower cylinder may include a cylindrical lower cylinder body (e.g., lower cylinder body 31 in the embodiment) that extends along the reference axis and a seat portion (e.g., seat portion 32 in the embodiment) that is provided at the upper end of the lower cylinder body, and the rotation mechanism may include a cylindrical rotating cylinder body (e.g., rotating cylinder body 41 in the embodiment) that extends along the reference axis and an abutment portion (e.g., abutment portion 42 in the embodiment) that is provided at the lower end of the rotating cylinder and abuts against the seat portion in the expanded state.

[0010] (5) In one aspect of the present invention, the contact portion may be released from contact with the seat portion by the rotation of the rotation mechanism.

[0011] (6) In one aspect of the present invention, the seat portion may protrude radially inward from the inner periphery of the upper end of the lower cylinder body and be provided in multiple locations spaced apart around the circumference of the lower cylinder body, and the abutment portion may protrude radially outward from the outer periphery of the lower end of the rotating cylinder body and be provided in multiple locations spaced apart around the circumference of the rotating cylinder body.

[0012] (7) In one aspect of the present invention, three of the seat portions may be provided and have a three-fold rotationally symmetric shape with respect to the center of the lower cylindrical body when viewed from the axial direction, and three of the abutment portions may be provided and have a three-fold rotationally symmetric shape with respect to the center of the rotating cylindrical body when viewed from the axial direction.

[0013] (8) In one aspect of the present invention, the lower cylindrical body may have a sliding groove (e.g., sliding groove 33 in the embodiment) along which the abutment portion can slide, and the sliding groove may extend parallel to the axial direction from the upper end to the lower end of the lower cylindrical body on the inner circumference of the lower cylindrical body.

[0014] (9) In one aspect of the present invention, the lower cylinder includes a cylindrical lower cylinder body (e.g., lower cylinder body 31 in the embodiments) that extends along the reference axis, and a seat portion (e.g., seat portion 32 in the embodiments) that is provided at the upper end of the lower cylinder body, and the guide structure includes a cylindrical guide cylinder body (e.g., guide cylinder body 51 in the embodiments) that is provided at the upper end of the upper cylinder in the axial direction relative to the seat portion and that extends along the reference axis, and a plurality of groove structures (e.g., groove structure 80 in the embodiments) that are periodically provided circumferentially on the inner circumference of the guide cylinder, and the rotation mechanism may include a cylindrical rotating cylinder body (e.g., rotating cylinder body 41 in the embodiments) that extends along the reference axis, and a plurality of convex structures (e.g., convex structure 70 in the embodiments) that are periodically provided circumferentially on the outer periphery of the rotating cylinder.

[0015] (10) In one aspect of the present invention, the groove structure includes a first groove (e.g., first groove 81 in the embodiment) extending parallel to the axial direction from the upper end to the lower end of the guide cylinder, a second groove (e.g., second groove 82 in the embodiment) extending from the middle of the first groove toward the upper end of the guide cylinder at an angle with respect to the axial direction and opening at the upper end of the guide cylinder, and a second groove (e.g., second groove 83) located closer to the lower end of the guide cylinder than the second groove, extending from the middle of the first groove toward the lower end of the guide cylinder at an angle with respect to the axial direction and opening at the lower end of the guide cylinder. and a third groove (e.g., third groove 83 in the embodiments) that extends parallel to the axial direction from the upper end to the lower end of the rotating cylindrical body, and the convex structure may include an extending portion (e.g., extending portion 71 in the embodiments) that extends parallel to the axial direction from the upper end to the lower end of the rotating cylindrical body, and a first convex portion (e.g., first convex portion 72 in the embodiments) and a second convex portion (e.g., second convex portion 73 in the embodiments) that protrude from the extending portion radially outward of the rotating cylindrical body and are provided at an interval from each other in the circumferential direction and the axial direction of the rotating cylindrical body so as to be slidable in any of the first groove, the second groove, and the third groove.

[0016] (11) In one aspect of the present invention, a shock absorber (e.g., shock absorber 60 in the embodiment) is housed inside the upper cylinder, and the shock absorber includes a rod (e.g., rod 62 in the embodiment) that extends along the axial direction and is rotatable around the reference axis, and the rotation mechanism may be attached to the tip of the rod.

[0017] (12) In one aspect of the present invention, the aircraft may further include a lower beam (e.g., lower beam 90 in the embodiment) having a first end rotatably connected to the aircraft and a second end rotatably connected to the lower cylinder.

[0018] (13) In one aspect of the present invention, the lower beams may be provided as a pair so that the first ends are connected to two locations on the aircraft, and an actuator (e.g., actuator 91 in the embodiment) that drives the landing legs and a transmission arm (e.g., transmission arm 92 in the embodiment) that transmits the driving force of the actuator to the lower cylinder may be provided between the pair of lower beams.

[0019] (14) In one aspect of the present invention, the actuator may be surrounded by the flying vehicle, the lower cylinder, and the pair of lower beams in the stored state.

[0020] (15) In one aspect of the present invention, when the landing gear transitions from the deployed state to the stowed state, the lower beam may be actuated in a direction away from the aircraft. [Effects of the Invention]

[0021] According to the above aspect (1), the landing leg of an aircraft is a landing leg of an aircraft used when landing, and comprises a first cylinder structure whose upper end is connected to the aircraft so as to be able to roll, and a second cylinder structure whose lower end is capable of contacting the ground, configured to be movable relative to the first cylinder structure in an axial direction along a reference axis, and configured to be rotatable relative to the first cylinder structure around the reference axis, and the first cylinder structure and the second cylinder structure switch the landing leg between a stored state and an deployed state by relative movement and relative rotation, thereby achieving the following effects. The landing gear can be switched between a retracted state and an extended state by the relative movement and rotation of the first cylinder structure and the second cylinder structure. Therefore, it is not necessary to manufacture and replace the landing gear every time the aircraft flies. Therefore, it is possible to provide a reusable landing gear for an aircraft.

[0022] According to the above aspect (2), the first cylinder structure comprises an upper cylinder whose upper end is rotatably connected to the flying body, and a rotation mechanism provided on the upper cylinder and rotatable around a reference axis, while the second cylinder structure comprises a lower cylinder whose lower end can contact the ground and which is movable axially relative to the upper cylinder, and a guide structure provided on the lower cylinder that guides the rotation of the rotation mechanism around the reference axis and the movement in the axial direction, thereby achieving the following effects. The landing gear can be switched between a retracted state and an extended state by rotating the rotation mechanism about the reference axis and moving it in the axial direction relative to the guide mechanism.

[0023] According to the above aspect (3), the rotation mechanism alternately rotates and moves relative to the guide structure in accordance with the axial movement of the lower cylinder, thereby alternately establishing the retracted state and the deployed state of the landing gear, thereby achieving the following effects. The rotation mechanism alternately rotates and moves relative to the guide structure, thereby allowing the landing legs to alternate between a retracted state and an extended state.

[0024] According to the above aspect (4), the lower cylinder comprises a cylindrical lower cylinder body along the reference axis and a seat portion provided at the upper end of the lower cylinder body, and the rotation mechanism comprises a cylindrical rotating cylinder body along the reference axis and an abutment portion provided at the lower end of the rotating cylinder and abutting against the seat portion in the deployed state, thereby achieving the following effects. When the landing gear is deployed, the abutment portion of the rotation mechanism abuts against the seat portion of the lower cylinder, maintaining the deployed state of the landing gear. This eliminates the need for a mechanism to maintain the deployed state, making it possible to reduce the weight, size, and cost of the landing gear.

[0025] According to the above aspect (5), the contact portion is released from contact with the seat portion by the rotation of the rotation mechanism, thereby achieving the following effects. The landing gear can transition from the deployed state to the stowed state by rotating the rotation mechanism, causing the abutment portion of the rotation mechanism to release from contact with the seat portion. Therefore, there is no need to provide a mechanism for releasing the abutment portion from contact with the seat portion. This allows for weight reduction, miniaturization, and cost reduction of the landing gear.

[0026] According to the above aspect (6), the seat portion protrudes radially inward from the inner periphery of the upper end of the lower cylindrical body and is provided in a plurality of positions spaced apart around the circumference of the lower cylindrical body, and the abutment portion protrudes radially outward from the outer periphery of the lower end of the rotating cylindrical body and is provided in a plurality of positions spaced apart around the circumference of the rotating cylindrical body, thereby achieving the following effects. The landing gear can be stably maintained in a deployed state by the multiple abutment portions abutting against the respective seating portions. Meanwhile, the landing gear can be transitioned from the deployed state to a stowed state by releasing the abutment of each abutment portion against each seating portion. When transitioning to the stowed state, each abutment portion of the rotating cylinder passes through the circumferential gaps (gaps) between each seating portion of the lower cylinder. Therefore, the landing gear can be prevented from expanding radially outward from the lower cylinder.

[0027] According to the above aspect (7), three seat portions are provided and have a rotationally symmetric shape with three-fold symmetry about the center of the lower cylindrical body when viewed from the axial direction, and three abutment portions are provided and have a rotationally symmetric shape with three-fold symmetry about the center of the rotating cylindrical body when viewed from the axial direction, thereby achieving the following effects. However, when two each of the seating surfaces and contacting portions are provided (when the central angle is 180° when viewed from the axial direction), the distance over which the rotation mechanism is rotated becomes longer, and the overstroke must be increased accordingly. On the other hand, when four or more each of the seating surfaces and contacting portions are provided, the area of ​​each seating surface and contacting portion becomes smaller, which may reduce the resistance to loads and impacts during landing. In contrast, according to the present embodiment, by providing three seating portions and three abutment portions, arranged in a three-fold symmetry, it is possible to suppress an increase in overstroke and to suppress a decrease in resistance to loads and impacts during landing.

[0028] According to the above aspect (8), the lower cylindrical body has a sliding groove along which the abutment portion can slide, and the sliding groove extends parallel to the axial direction from the upper end to the lower end of the lower cylindrical body on the inner circumference of the lower cylindrical body, thereby achieving the following effects. When the landing gear is retracted or deployed, the abutment portion at the lower end of the rotating cylinder can move parallel to the axial direction along the sliding groove on the periphery of the lower cylinder. This allows the rotating mechanism to move stably relative to the lower cylinder. In addition, if the rotating mechanism is attached to the end of the rod of a shock absorber, swinging of the rotating mechanism can be suppressed. This can prevent deterioration of the shock absorber.

[0029] According to the above aspect (9), the lower cylinder comprises a cylindrical lower cylinder body along the reference axis and a seat portion provided at the upper end of the lower cylinder body, the guide structure is provided axially closer to the upper end of the upper cylinder than the seat portion and comprises a cylindrical guide cylinder body along the reference axis and a plurality of groove structures provided periodically in the circumferential direction on the inner circumference of the guide cylinder, and the rotation mechanism comprises a cylindrical rotating cylinder body along the reference axis and a plurality of convex structures provided periodically in the circumferential direction on the outer periphery of the rotating cylinder, thereby achieving the following effects. The periodic groove structure of the guide structure and the periodic convex structure of the rotation mechanism work together to allow the rotation mechanism to alternately rotate and move relative to the guide structure. This eliminates the need for a mechanism to apply power to operate the rotation mechanism. This allows for weight reduction, miniaturization, and cost reduction of the landing gear.

[0030] According to the above aspect (10), the groove structure comprises a first groove extending parallel to the axial direction from the upper end to the lower end of the guide cylindrical body, a second groove extending from the middle of the first groove towards the upper end of the guide cylindrical body at an angle with respect to the axial direction and opening at the upper end of the guide cylindrical body, and a third groove located closer to the lower end of the guide cylindrical body than the second groove, extending from the middle of the first groove towards the lower end of the guide cylindrical body at an angle with respect to the axial direction and opening at the lower end of the guide cylindrical body, and the convex structure comprises an extending portion extending parallel to the axial direction from the upper end to the lower end of the rotating cylindrical body, and a first convex portion and a second convex portion protruding from the extending portion radially outward of the rotating cylindrical body and arranged at a distance from each other in the circumferential and axial directions of the rotating cylindrical body so as to be slidable in any of the first groove, second groove, and third groove, thereby achieving the following effects. The first, second, and third grooves of the groove structure cooperate with the first and second convex portions of the convex structure to allow the rotation mechanism to alternately rotate and move relative to the guide structure. This eliminates the need for a mechanism that applies power to operate the rotation mechanism. This allows for weight, size, and cost reductions for the landing gear. Additionally, the second and third grooves are inclined relative to the first groove, allowing for smooth axial movement of the lower cylinder and smooth retraction and deployment of the landing gear.

[0031] According to the above aspect (11), a shock absorber is housed inside the upper cylinder, the shock absorber has a rod that extends along the axial direction and is rotatable around a reference axis, and the rotation mechanism is attached to the tip of the rod, thereby achieving the following effects. The shock absorber can absorb the impact during landing that is transmitted from the upper end of the lower cylinder to the lower end of the rotation mechanism. In addition, because the shock absorber rod can rotate around the reference axis and the rotation mechanism is attached to the end of the rod, there is no need to provide a mechanism to rotate the rotation mechanism. This makes it possible to reduce the weight, size, and cost of the landing gear.

[0032] According to the above aspect (12), by further including a lower beam whose first end is rotatably connected to the flying body and whose second end is rotatably connected to the lower cylinder, the following effects are achieved. When the landing gear alternates between a retracted state and an extended state, the lower beam can stably support the lower cylinder. For example, when the aircraft is flying, the landing gear can be compactly retracted by bringing the lower beam close to the aircraft and moving the lower cylinder toward the upper end of the upper cylinder. For example, when the aircraft is landing, the aircraft can be stabilized by positioning the lower end of the lower cylinder away from the aircraft.

[0033] According to the above aspect (13), a pair of lower beams are provided so that the first ends are connected to two points on the aircraft, and an actuator that drives the landing gear and a transmission arm that transmits the driving force of the actuator to the lower cylinder are provided between the pair of lower beams, thereby achieving the following effects. When the lower end of the lower cylinder comes into contact with the ground with the landing gear deployed, the load can be borne by the transmission arm. This reduces the burden on other parts during landing. For example, the transmission arm can absorb the landing load, thereby realizing a structure that protects the actuator. However, if an actuator were attached to each of the pair of lower beams, the actuator would need to absorb impacts during landing, which could result in the actuator becoming larger. In contrast, according to this aspect, the actuator is provided between the pair of lower beams, so the actuator only needs to have enough driving force to drive the landing gear. This allows the actuator to be smaller and costs to be reduced.

[0034] According to the above aspect (14), the actuator is surrounded by the flying body, the lower cylinder, and the pair of lower beams in the stored state, which provides the following effects. The actuator in the stowed state can be protected from external factors by the flying vehicle, the lower cylinder, and the pair of lower beams. For example, when the landing gear is folded, the landing gear covers the actuator during flight of the flying vehicle, preventing wear on the actuator. However, if components such as actuators protrude significantly radially outward of the aircraft when the landing gear is retracted, the aerodynamic performance of the aircraft may be reduced. In contrast, according to this aspect, the actuators are surrounded by the aircraft, the lower cylinder, and the pair of lower beams when the landing gear is retracted, so that the components protrude as compactly as possible radially outward of the aircraft. Therefore, the reduction in the aerodynamic performance of the aircraft can be minimized.

[0035] According to the above aspect (15), when the landing gear transitions from the deployed state to the stowed state, the lower beam is actuated in a direction away from the aircraft, thereby achieving the following effects. The direction in which the lower beam is moved away from the aircraft is the direction in which the lower end of the rotation mechanism is moved away from the upper end of the lower cylinder. This allows the rotation mechanism to operate without applying excessive force to the lower end of the rotation mechanism, allowing for smooth operation of the rotation mechanism. [Brief explanation of the drawings]

[0036] [Figure 1]FIG. 2 is a perspective view showing the deployed state of the landing gear of the aircraft according to the embodiment. [Figure 2] FIG. 2 is a perspective view showing the landing gear of the aircraft in the retracted state according to the embodiment. [Figure 3] FIG. 2 is an overall perspective view of a landing gear of the aircraft according to the embodiment. [Figure 4] FIG. 2 is a partially enlarged perspective view of a landing gear of the aircraft according to the embodiment. [Figure 5] FIG. 1 is a perspective view of a shock absorber according to an embodiment. [Figure 6] FIG. 2 is a perspective view showing a rotation mechanism and a guide structure according to the embodiment. [Figure 7] FIG. 2 is a perspective view of a guide structure according to the embodiment. [Figure 8] FIG. 2 is a perspective view of a lower cylinder according to the embodiment. [Figure 9] FIG. 10 is an explanatory diagram illustrating the arrangement of the contact portion and the seat portion in the deployed state of the embodiment. [Figure 10] FIG. 10 is an explanatory diagram illustrating the arrangement of the contact portion and the seat portion in the stored state of the embodiment. [Figure 11] 10A and 10B are explanatory diagrams illustrating the operation of the rotation mechanism when the landing gear is extended in the embodiment. [Figure 12] 10A and 10B are explanatory diagrams illustrating the operation of the rotation mechanism at the start of an overstroke in the embodiment. [Figure 13] 10A and 10B are explanatory diagrams illustrating the operation of the rotation mechanism of the embodiment immediately before the first rotation. [Figure 14] 10A and 10B are explanatory diagrams illustrating the operation of the rotation mechanism of the embodiment immediately after the first rotation. [Figure 15] 10A and 10B are explanatory diagrams illustrating the operation when returning from an overstroke position in the embodiment. [Figure 16] 10A and 10B are explanatory diagrams illustrating the operation of the rotation mechanism of the embodiment immediately before the second rotation. [Figure 17] 10A and 10B are explanatory diagrams illustrating the operation of the rotation mechanism of the embodiment immediately after the second rotation. [Figure 18] 10A and 10B are explanatory diagrams illustrating an operation when the upper cylinder of the embodiment is housed in the lower cylinder. [Figure 19] 5A and 5B are diagrams for explaining one-motion operation of a transmission arm and a cylinder mechanism according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0037] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will now be described with reference to the accompanying drawings. In the embodiment, a landing gear of an aircraft used during landing will be described as an example.

[0038] <Landing legs of flying vehicle> As shown in Fig. 1, the landing leg 2 of the aircraft 1 (hereinafter simply referred to as "landing leg 2") comprises a cylinder mechanism 3 that is extendable and retractable in an axial direction along a reference axis CL, and a link mechanism 4 that connects the aircraft 1 and the cylinder mechanism 3. The landing leg 2 can be switched between a deployed state shown in Fig. 1 and a retracted state shown in Fig. 2.

[0039] The example in Figure 1 shows an aircraft 1 standing vertically relative to the ground. The top of the paper in Figure 1 corresponds to the upper side in the vertical direction. The bottom of the paper in Figure 1 corresponds to the lower side in the vertical direction (towards the ground). The aircraft 1 is equipped with a lower structure 10 that extends in the up-down direction (vertical direction). Multiple landing legs 2 (for example, four) are provided on the lower structure 10 of the aircraft 1. In the example in Figure 1, one of the four landing legs 2 is shown, and the other landing legs 2 are not shown.

[0040] The lower structure 10 includes a plurality of support columns 11 extending in the vertical direction and a cross structure 12 connecting two adjacent support columns 11. There are four support columns 11. The four support columns 11 are arranged at positions corresponding to the corners of a rectangle when viewed from the vertical direction.

[0041] The cross structure 12 includes upper cross members 13 that connect the upper ends of two adjacent columns 11, and lower cross members 14 that connect the lower ends of two adjacent columns 11. The upper cross members 13 are curved toward the outside of the lower structure 10 when viewed from the vertical direction. The lower cross members 14 are arranged at positions that correspond to the sides of the rectangle when viewed from the vertical direction.

[0042] <Cylinder mechanism> The cylinder mechanism 3 comprises a first cylinder structure 3A whose upper end is rotatably connected to the aircraft 1, and a second cylinder structure 3B whose lower end is capable of contacting the ground, is configured to be movable relative to the first cylinder structure 3A in the axial direction along the reference axis CL, and is configured to be rotatable around the reference axis CL relative to the first cylinder structure 3A. The first cylinder structure 3A and the second cylinder structure 3B switch the landing legs 2 between a retracted state and an extended state by the relative movement and rotation.

[0043] The first cylinder structure 3A includes an upper cylinder 20 whose upper end is rotatably connected to the aircraft 1, and a rotation mechanism 40 provided on the upper cylinder 20 and rotatable about the reference axis CL. The second cylinder structure 3B comprises a lower cylinder 30 whose lower end can contact the ground and which can move axially along the reference axis CL relative to the upper cylinder 20, and a guide structure 50 provided on the lower cylinder 30 to guide the rotation of the rotation mechanism 40 around the reference axis CL and the movement in the axial direction.

[0044] <Upper cylinder> The upper cylinder 20 constitutes the inner cylinder of the cylinder mechanism 3. The upper cylinder 20 is formed in a cylindrical shape along the reference axis CL. The upper end of the upper cylinder 20 is rotatably connected to the aircraft 1 via a joint 15 provided on the upper horizontal member 13. The upper end of the upper cylinder 20 is rotatable around the axis C1 of the joint 15 provided on the upper horizontal member 13. The axis C1 (hereinafter also referred to as the "first axis C1") of the joint 15 provided on the upper horizontal member 13 is perpendicular to the reference axis CL. When viewed from the top-bottom direction, the first axis C1 is parallel to a straight line connecting the centers of the two support columns 11 located on both ends of the upper horizontal member 13. The upper end of the upper cylinder 20 may be rotatable around the reference axis CL.

[0045] As shown in Figure 4, a shock absorber 60 is housed inside the upper cylinder 20. The shock absorber 60 is a shock absorbing device that absorbs shock acting on the landing leg 2. The shock absorber 60 is extendable and contractible relative to the upper cylinder 20 in the axial direction along the reference axis line CL.

[0046] 5, shock absorber 60 is formed in a cylindrical shape along reference axis CL and includes an inner cylinder 61 provided radially inside upper cylinder 20, a rod 62 extending axially and rotatable about reference axis CL, a cap 63 attached to the tip (lower axial end) of rod 62, and a spring 64 provided between inner cylinder 61 and cap 63. Cap 63 is provided with a female thread portion (not shown) into which a bolt can be threaded.

[0047] <Lower cylinder> As shown in Fig. 3, the lower cylinder 30 constitutes the outer cylinder of the cylinder mechanism 3. The lower cylinder 30 is movable in the axial direction along the reference axis CL relative to the upper cylinder 20. The lower cylinder 30 is provided coaxially with the upper cylinder 20. As shown in Fig. 8, the lower cylinder 30 includes a cylindrical lower cylinder body 31 that is aligned with the reference axis CL, and a seat portion 32 provided at the upper end of the lower cylinder body 31.

[0048] As shown in Fig. 1, the outer shape of the lower cylinder 31 is larger than the outer shape of the upper cylinder 20 when viewed in the axial direction. The lower end of the lower cylinder 31 can come into contact with the ground in the deployed state. As shown in Fig. 2, the lower end of the lower cylinder 31 is close to the lower cross member 14 in the stored state.

[0049] 8, the seating surface portions 32 protrude radially inward from the inner periphery at the upper end of the lower cylinder body 31. A plurality of seating surface portions 32 are provided at intervals in the circumferential direction of the lower cylinder body 31. Three seating surface portions 32 are provided.

[0050] Fig. 9 is an explanatory diagram of the arrangement of the contact portion and the seat portion in the deployed state of the embodiment. Fig. 10 is an explanatory diagram of the arrangement of the contact portion and the seat portion in the stored state of the embodiment. In each figure, the upper part of the page shows the "lower cylinder with the seat portion," and the lower part of the page shows the "rotation mechanism with the contact portion." 10, when viewed from the axial direction, the seating surface portion 32 has a shape that is rotationally symmetric with three times symmetry about the center of the lower cylinder body 31. When viewed from the axial direction, the seating surface portion 32 is formed in an arc shape that follows the outer periphery of the rotating cylinder body 41 of the rotation mechanism 40.

[0051] The lower cylinder body 31 has a sliding groove 33 in which the abutment portion 42 of the rotation mechanism 40 can slide. The sliding groove 33 extends parallel to the axial direction from the upper end to the lower end of the lower cylinder body 31 on the inner circumference of the lower cylinder body 31. A plurality of sliding grooves 33 are provided at intervals in the circumferential direction of the lower cylinder body 31. Three sliding grooves 33 are provided. When viewed from the axial direction, the sliding grooves 33 have a rotationally symmetric shape with three-fold symmetry about the center of the lower cylinder body 31. When viewed from the axial direction, the sliding groove 33 is provided between two circumferentially adjacent seating surface portions 32. When viewed from the axial direction, the sliding groove 33 includes an inner groove 34 formed on the radially inner side of the lower cylinder body 31 and an outer groove 35 connected to the inner groove 34.

[0052] <Rotation mechanism> The rotation mechanism 40 alternately rotates and moves relative to the guide structure 50 in accordance with the axial movement of the lower cylinder 30, thereby alternately establishing a retracted state and an extended state of the landing gear 2. As shown in Fig. 4, the rotation mechanism 40 is provided coaxially with the upper cylinder 20. The rotation mechanism 40 includes a cylindrical rotating cylinder 41 extending along the reference axis CL, a contact portion 42 provided at the lower end of the rotating cylinder 41 and contacting the seat portion 32 in the extended state, a plurality of convex structures 70 provided periodically in the circumferential direction on the outer periphery of the rotating cylinder 41, and a cover 43 provided at the lower end of the rotating cylinder 41.

[0053] The outer shape of the rotating cylinder 41 is larger than the outer shape of the upper cylinder 20 when viewed in the axial direction. The outer shape of the rotating cylinder 41 is smaller than the outer shape of the lower cylinder 31 when viewed in the axial direction. The inner circumferential surface of the rotating cylinder 41 is formed in a circular shape that follows the inner circumferential surface of the upper cylinder 20 when viewed in the axial direction. As shown in FIG. 10 , the outer circumferential surface of the rotating cylinder 41 is curved along the inner circumferential surface of the lower cylinder 31 (the arcuate surface of the seat portion 32) when viewed in the axial direction.

[0054] As shown in Fig. 4, the abutment portion 42 abuts against the seat portion 32 in the deployed state. The abutment portion 42 releases its abutment against the seat portion 32 as the rotation mechanism 40 rotates. The abutment portion 42 protrudes radially outward from the outer periphery of the lower end of the rotating cylinder 41. A plurality of the abutment portions 42 are provided at intervals in the circumferential direction of the rotating cylinder 41. Three abutment portions 42 are provided.

[0055] As shown in Fig. 9, the contact portions 42 have a three-fold rotationally symmetric shape with respect to the center of the rotating barrel 41 when viewed in the axial direction. When viewed in the axial direction, the contact portions 42 are formed in an arc shape that follows the outer periphery of the rotating barrel 41. When viewed in the axial direction, each contact portion 42 overlaps with each seat portion 32 when viewed in the axial direction. When viewed in the axial direction, each contact portion 42 overlaps with the inner groove 34 of each slide groove 33 when viewed in the axial direction. As shown in Fig. 10, when viewed in the stowed state, each contact portion 42 overlaps with the inner groove 34 of each slide groove 33.

[0056] Fig. 6 is a perspective view showing a rotation mechanism and a guide structure of the embodiment. In Fig. 10, the upper part of the page shows a "rotation mechanism having a convex structure" and the lower part of the page shows a "guide structure having a groove structure." As shown in Figure 6, the convex structure 70 includes an extension portion 71 extending parallel to the axial direction from the upper end to the lower end of the rotating barrel 41, and a first convex portion 72 and a second convex portion 73 that protrude radially outward from the extension portion 71 and are spaced apart from each other in the circumferential and axial directions of the rotating barrel 41 so as to be able to slide into any of the first groove 81, second groove 82, and third groove 83 that constitute the groove structure 80.

[0057] The extension portions 71 protrude radially outward from the outer periphery of the rotating barrel 41. A plurality of extension portions 71 are provided at intervals around the circumferential direction of the rotating barrel 41. Three extension portions 71 are provided. As shown in FIG. 9, the extension portions 71 have a rotationally symmetric shape with three-fold symmetry about the center of the rotating barrel 41 when viewed from the axial direction. When viewed from the axial direction, the extension portions 71 are formed in an arc shape that follows the outer periphery of the rotating barrel 41. When viewed from the axial direction, each extension portion 71 overlaps with a corresponding abutment portion 42. When viewed from the axial direction, each extension portion 71 overlaps with an inner groove 34 of a corresponding slide groove 33 when viewed from the axial direction. As shown in FIG. 10, when in the stored state, each extension portion 71 overlaps with a corresponding contact portion 42.

[0058] As shown in FIG. 6 , the first protrusion 72 is provided on the upper part of the extension part 71. For example, the first protrusion 72 is a rotating body attached to the upper part of the extension part 71 via a bearing. The first protrusion 72 has a circular shape when viewed from the radial direction of the rotary cylindrical body 41. For example, the first protrusion 72 may be the head of a bolt attached to a female threaded portion provided on the upper part of the extension part 71. For example, the configuration of the first protrusion 72 can be changed according to required specifications.

[0059] The second protrusion 73 is provided on the lower part of the extending portion 71. For example, the second protrusion 73 is a rotating body attached to the lower part of the extending portion 71 via a bearing. The second protrusion 73 has a circular shape when viewed from the radial direction of the rotating cylindrical body 41. The first protrusion 72 and the second protrusion 73 are formed to have the same shape. For example, the second protrusion 73 may be the head of a bolt attached to a female threaded portion provided on the lower part of the extending portion 71. For example, the configuration of the second protrusion 73 can be changed according to required specifications.

[0060] One first protrusion 72 and one second protrusion 73 are provided for each of the three extending portions 71. As shown in FIG. 9, the first protrusion 72 and the second protrusion 73 have a three-fold rotationally symmetric shape with respect to the center of the rotating barrel 41 when viewed in the axial direction. The first protrusions 72 and the second protrusions 73 in each extending portion 71 are arranged at central angle intervals of 30° when viewed in the axial direction. Here, the central angles of the first protrusions 72 and the second protrusions 73 refer to the angles formed by a line segment passing through the center of the rotating barrel 41 and the center of the first protrusion 72 and a line segment passing through the center of the rotating barrel 41 and the center of the second protrusion 73 when viewed in the axial direction. As shown in FIG. 10, each of the first protrusions 72 and the second protrusions 73 overlaps with the outer groove 35 of each sliding groove 33 when viewed in the axial direction in the stored state.

[0061] 9, the cover 43 has a shape that follows the outer periphery of the rotating cylinder 41 when viewed in the axial direction. The cover 43 has a plurality of (six in this embodiment) insertion holes 44 through which bolts can be inserted. The six insertion holes 44 are arranged at equal intervals in the circumferential direction of the cover 43.

[0062] 4, the rotation mechanism 40 is attached to the tip of the rod 62. For example, bolts are inserted into the insertion holes 44 of the lid 43 and screwed into the female threads of the cap 63. This allows the lid 43 of the rotation mechanism 40 to be fixed to the cap 63 at the tip of the rod 62.

[0063] <Guide structure> As shown in FIG. 1, the guide structure 50 is provided coaxially with the upper cylinder 20. The guide structure 50 is provided axially closer to the upper end of the upper cylinder 20 than the seat surface portion 32. The guide structure 50 is fixed to the lower cylinder 30 by a bracket or the like. The guide structure 50 is movable axially together with the lower cylinder 30 relative to the upper cylinder 20. As shown in FIG. 7, the guide structure 50 includes a cylindrical guide cylinder body 51 extending along a reference axis CL, and a plurality of groove structures 80 periodically provided in the circumferential direction on the inner circumference of the guide cylinder body 51.

[0064] As shown in Fig. 6, the outer shape of the guide cylindrical body 51 is larger than the outer shape of the rotating cylindrical body 41 when viewed in the axial direction. As shown in Fig. 1, the lower end of the guide cylindrical body 51 is located axially above the upper end of the lower cylindrical body 31. In the figure, reference numeral 25 denotes a slider located axially above the upper end of the guide cylindrical body 51. The slider 25 is formed in a cylindrical shape that follows the outer periphery of the upper cylinder 20.

[0065] 7, the groove structure 80 is provided in six regions A1 to A6 in the circumferential direction of the guide cylindrical body 51. The six regions A1 to A6 are regions obtained by dividing the guide cylindrical body 51 into six equal parts in the circumferential direction when viewed in the axial direction. The groove structure 80 is recessed from the inner circumferential surface of the guide cylindrical body 51 toward the radially outward direction.

[0066] The groove structure 80 comprises a first groove 81 extending parallel to the axial direction from the upper end to the lower end of the guide cylinder 51, a second groove 82 extending from halfway along the first groove 81 at an angle relative to the axial direction toward the upper end of the guide cylinder 51 and opening at the upper end of the guide cylinder 51, and a third groove 83 located closer to the lower end of the guide cylinder 51 than the second groove 82, extending from halfway along the first groove 81 at an angle relative to the axial direction toward the lower end of the guide cylinder 51 and opening at the lower end of the guide cylinder 51.

[0067] The first groove 81 extends linearly parallel to the axial direction. The second groove 82 includes an upper inclined groove 84 extending at an angle from the upper part of the first groove 81, and an upper open groove 85 extending from the upper end of the upper inclined groove 84 toward the upper end of the guide cylinder 51. The third groove 83 includes a lower inclined groove 86 extending at an angle from the lower part of the first groove 81, and a lower open groove 87 extending from the lower end of the lower inclined groove 86 toward the lower end of the guide cylinder 51.

[0068] When viewed in the axial direction, the first groove 81 has a six-fold rotationally symmetric shape with respect to the center of the guide cylinder 51. The upper-opening groove 85 of the second groove 82 has a six-fold rotationally symmetric shape with respect to the center of the guide cylinder 51. The first grooves 81 and the upper-opening grooves 85 in each groove structure 80 are arranged at central angle intervals of 30° when viewed in the axial direction. Here, the central angles of the first grooves 81 and the upper-opening grooves 85 refer to the angles formed by a line segment passing through the center of the guide cylinder 51 and the center of the first groove 81 and a line segment passing through the center of the rotating cylinder 41 and the center of the upper-opening groove 85 when viewed in the axial direction.

[0069] The lower-side open groove 87 of the third groove 83 is provided on an extension line of the upper-side open groove 85 of the second groove 82. The lower-side open groove 87 of the third groove 83 has a rotationally symmetric shape with six-fold symmetry about the center of the guide cylinder 51. The first grooves 81 and the lower-side open grooves 87 in each groove structure 80 are arranged at central angle intervals of 30° when viewed from the axial direction. Here, the central angle of the first groove 81 and the lower-side open groove 87 refers to the angle formed by a line segment passing through the center of the guide cylinder 51 and the center of the first groove 81 and a line segment passing through the center of the rotating cylinder 41 and the center of the lower-side open groove 87 when viewed from the axial direction. The first grooves 81 and the upper-side open groove 85, and the first grooves 81 and the lower-side open groove 87 in each groove structure 80 are arranged at the same central angle when viewed from the axial direction.

[0070] <Link mechanism> As shown in FIG. 1 , the link mechanism 4 includes a lower beam 90 having a first end rotatably connected to the aircraft 1 and a second end rotatably connected to the lower cylinder 30. The first end of the lower beam 90 is rotatably connected to the aircraft 1 via a joint 16 provided on the lower bridging member 14. The first end of the lower beam 90 is rotatable about an axis C2 of the joint 16 provided on the lower bridging member 14. The axis C2 of the joint 16 provided on the lower bridging member 14 (hereinafter also referred to as the "second axis C2") is parallel to the longitudinal direction of the lower bridging member 14. The second axis C2 is parallel to the first axis C1.

[0071] A second end of the lower beam 90 is rotatably connected to the lower cylinder 30 via a joint 39 provided in the lower cylinder 30. The second end of the lower beam 90 is rotatable about an axis C3 of the joint 39 provided in the lower cylinder 30. The axis C3 (hereinafter also referred to as the "third axis C3") of the joint 39 provided in the lower cylinder 30 is parallel to the first axis C1. That is, the first axis C1, the second axis C2, and the third axis C3 are parallel to one another.

[0072] A pair of lower beams 90 are provided so that first ends thereof are connected to two locations on the aircraft 1. The first ends of the pair of lower beams 90 are connected to the lower cross member 14 near the lower ends of the corresponding two pillars 11. In the deployed state, the pair of lower beams 90 extend horizontally outward from their respective first ends and then extend toward each other toward their second ends on the lower cylinder 30 side.

[0073] Between the pair of lower beams 90, there are provided an actuator 91 that drives the landing legs 2, and a transmission arm 92 that transmits the driving force of the actuator 91 to the lower cylinder 30. The actuator 91 is attached to the longitudinal center of the lower cross member 14. As shown in FIG. 2, the actuator 91 is surrounded by the aircraft 1, the lower cylinder 30, and the pair of lower beams 90 in the stowed state.

[0074] 4, the actuator 91 includes a motor 93 and a power transmission mechanism 94 that transmits the rotational power of the motor 93 to a first end of the transmission arm 92. The motor 93 has an output shaft that outputs the rotational power of the motor 93. An axis D1 of the output shaft of the motor 93 (hereinafter also referred to as the "output axis D1") is parallel to the second axis C2.

[0075] The power transmission mechanism 94 includes a first transmission shaft 95 that transmits the rotational power of the motor 93 to a first end of the transmission arm 92, and a connecting member 96 that connects the output shaft of the motor 93 to the first transmission shaft 95. In the deployed state, the first transmission shaft 95 is disposed below the output shaft of the motor 93. An axis D2 of the first transmission shaft 95 (hereinafter also referred to as the "first transmission axis D2") is parallel to the output axis D1.

[0076] A first end of the transmission arm 92 is rotatably connected to the power transmission mechanism 94. The first end of the transmission arm 92 is rotatable about a first transmission axis D2. A second end of the transmission arm 92 is rotatably connected to the lower beam 90 via a second transmission shaft 97 and a joint 98 provided at a portion of the lower beam 90 on the second end side. An axis D3 of the second transmission shaft 97 (hereinafter also referred to as the "second transmission axis D3") is parallel to the first transmission axis D2. The second end of the transmission arm 92 is rotatable about the second transmission axis D3.

[0077] When the landing gear 2 transitions from the deployed state shown in FIG. 1 to the stowed state shown in FIG. 2, the lower beam 90 is operated in a direction away from the aircraft 1. For example, in the deployed state shown in FIG. 4, the motor 93 is rotated in the direction of arrow R1 (forward rotation). This causes the first transmission shaft 95 to move in the direction of arrow R1, which pulls the first end of the transmission arm 92 in the direction of arrow R1. This causes the second end (second transmission shaft 97) of the transmission arm 92 to move downward, which moves the lower cylinder 30 axially downward. In other words, the cylinder mechanism 3 extends further (hereinafter also referred to as "overstroke") from the deployed state shown in FIG. 1.

[0078] In the overstroke state, when the motor 93 is further rotated in the direction of arrow R1, the first transmission shaft 95 moves further in the direction of arrow R1, and the first end of the transmission arm 92 is further pulled in the direction of arrow R1. As a result, the second end (second transmission shaft 97) of the transmission arm 92 moves upward, and the lower cylinder 30 moves upward in the axial direction. In other words, the cylinder mechanism 3 retracts from the overstroke state. This causes the landing gear 2 to transition to the stowed state shown in FIG. 2. Therefore, forward rotation of the motor 93 allows the landing gear 2 to transition from the deployed state, via the overstroke state, to the stowed state.

[0079] On the other hand, when the landing gear 2 transitions from the stowed state shown in FIG. 2 to the deployed state shown in FIG. 1, the operation performed by the landing gear 2 is the reverse of that performed when transitioning from the deployed state to the stowed state. For example, in the stowed state, the motor 93 is rotated in the direction opposite to the direction of arrow R1 (reverse rotation). This causes the first transmission shaft 95 to move in the direction opposite to the direction of arrow R1, pushing the first end of the transmission arm 92 in the direction opposite to the direction of arrow R1. This causes the second end (second transmission shaft 97) of the transmission arm 92 to move downward, causing the lower cylinder 30 to move axially downward. The cylinder mechanism 3 further extends from the deployed state and transitions to an overstroke state.

[0080] In the overstroke state, when the motor 93 is further rotated in the direction opposite to the direction of arrow R1, the first transmission shaft 95 moves further in the direction opposite to the direction of arrow R1, and the first end of the transmission arm 92 is pulled in the direction opposite to the direction of arrow R1. As a result, the second end (second transmission shaft 97) of the transmission arm 92 moves upward, and the lower cylinder 30 moves upward in the axial direction. In other words, the cylinder mechanism 3 contracts from the overstroke state. This causes the landing gear 2 to transition to the deployed state shown in FIG. 1. Therefore, the reverse rotation of the motor 93 allows the landing gear 2 to transition from the retracted state, via the overstroke state, to the deployed state.

[0081] <An example of landing gear movement> Next, an example of the operation of the landing gear 2 of the embodiment will be described with reference to FIGS. FIG. 11 is an explanatory diagram of the operation of the rotation mechanism 40 when the landing gear 2 is extended in the embodiment. FIG. 12 is an explanatory diagram of the operation of the rotation mechanism 40 at the start of the overstroke in the embodiment. FIG. 13 is an explanatory diagram of the operation of the rotation mechanism 40 immediately before the first rotation in the embodiment. FIG. 14 is an explanatory diagram of the operation of the rotation mechanism 40 immediately after the first rotation in the embodiment. FIG. 15 is an explanatory diagram of the operation when returning from the overstroke position in the embodiment. FIG. 16 is an explanatory diagram of the operation of the rotation mechanism 40 immediately before the second rotation in the embodiment. FIG. 17 is an explanatory diagram of the operation of the rotation mechanism 40 immediately after the second rotation in the embodiment. FIG. 18 is an explanatory diagram of the operation when the upper cylinder 20 in the embodiment is stored in the lower cylinder 30. In each figure, the left side of the page shows the "positional relationship of the abutment portion 42 of the rotation mechanism 40 with respect to the seat portion 32 of the lower cylinder 30," the center side of the page shows the "positional relationship of the first convex portion 72 and the second convex portion 73 with respect to the groove structure 80," and the right side of the page shows the "positional relationship of the rotation mechanism 40 with respect to the guide structure 50." The groove structure 80 shows two groove structures 80A and 80B that are adjacent to each other in the circumferential direction in the guide structure 50.

[0082] As shown in Figure 11, when the landing leg 2 is extended, the abutment portion 42 overlaps with the seat portion 32 when viewed from the axial direction. When the landing leg 2 is extended, the first convex portion 72 is positioned in the vertical center of the first groove 81 in one groove structure 80A. When the landing leg 2 is extended, the second convex portion 73 is positioned below the third groove 83 in one groove structure 80A. When the landing leg 2 is extended, the lower end of the rotation mechanism 40 is positioned below the guide structure 50. After the operation in Figure 11, the operation proceeds to the operation in Figure 12.

[0083] As shown in Figure 12, at the start of the overstroke, the abutment portion 42 overlaps with the seat portion 32 when viewed from the axial direction. At the start of the overstroke, the first convex portion 72 is positioned at the upper end of the first groove 81 in one groove structure 80A. At the start of the overstroke, the second convex portion 73 is positioned at the lower end of the third groove 83 in one groove structure 80A. At the start of the overstroke, the upper end of the rotation mechanism 40 is positioned above the guide structure 50. After the operation in Figure 12, the operation transitions to the operation in Figure 13.

[0084] As shown in Figure 13, immediately before the first rotation of the rotation mechanism 40, the abutment portion 42 overlaps with the seat portion 32 when viewed from the axial direction. Immediately before the first rotation of the rotation mechanism 40, the first convex portion 72 is positioned above the first groove 81 in one groove structure 80A. Immediately before the first rotation of the rotation mechanism 40, the second convex portion 73 is positioned at the bent portion of the third groove 83 in one groove structure 80A. Immediately before the first rotation of the rotation mechanism 40, the lower end of the rotation mechanism 40 is positioned inside the guide structure 50. After the operation in Figure 13, the operation transitions to the operation in Figure 14.

[0085] As shown in FIG. 14 , immediately after the first rotation of the rotation mechanism 40, the abutment portion 42 overlaps with a portion of the seat portion 32 and a portion of the slide groove 33 when viewed from the axial direction. Immediately after the first rotation of the rotation mechanism 40, the first protrusion 72 is positioned above the second groove 82 in the other groove structure 80B. Immediately after the first rotation of the rotation mechanism 40, the second protrusion 73 is positioned at the intersection of the first groove 81 and the third groove 83 in the one groove structure 80A. Immediately after the first rotation of the rotation mechanism 40, the rotation mechanism 40 completes a 30° rotation around the reference axis CL. Immediately after the first rotation of the rotation mechanism 40, the first protrusion 72 and the second protrusion 73 move further upward from the positions shown in FIG. 14 . Thereafter, the first protrusion 72 and the second protrusion 73 stop at the over-stroke position (terminal position). After the operation shown in FIG. 14 , the operation proceeds to the operation shown in FIG. 15 .

[0086] As shown in Figure 15, when returning from the over-stroke position, the abutment portion 42 overlaps with part of the seat portion 32 and part of the slide groove 33 when viewed from the axial direction. When returning from the over-stroke position, the first convex portion 72 is positioned at the upper end of the second groove 82 in the other groove structure 80B. When returning from the over-stroke position, the second convex portion 73 is positioned at the lower end of the first groove 81 in the one groove structure 80A. When returning from the over-stroke position, the lower end of the rotation mechanism 40 is positioned inside the guide structure 50. After the operation in Figure 15, the operation transitions to the operation in Figure 16.

[0087] As shown in Figure 16, immediately before the second rotation of the rotation mechanism 40, the abutment portion 42 overlaps with a portion of the seat portion 32 and a portion of the slide groove 33 when viewed from the axial direction. Immediately before the second rotation of the rotation mechanism 40, the first convex portion 72 is disposed at the bent portion of the second groove 82 in the other groove structure 80B. Immediately before the second rotation of the rotation mechanism 40, the second convex portion 73 is disposed below the first groove 81 in one groove structure 80A. Immediately before the second rotation of the rotation mechanism 40, the lower end of the rotation mechanism 40 is disposed below the guide structure 50. After the operation in Figure 16, the process transitions to the operation in Figure 17.

[0088] As shown in FIG. 17, immediately after the second rotation of the rotation mechanism 40, the abutment portion 42 does not overlap with the seat portion 32 when viewed in the axial direction, but overlaps with the slide groove 33. Immediately after the second rotation of the rotation mechanism 40, the first convex portion 72 is disposed at the intersection of the first groove 81 and the second groove 82 in the other groove structure 80B. Immediately after the second rotation of the rotation mechanism 40, the second convex portion 73 is disposed below the third groove 83 in the other groove structure 80B. Immediately after the second rotation of the rotation mechanism 40, the rotation mechanism 40 completes a 30° rotation about the reference axis line CL (a 60° rotation including the first rotation). After the operation of FIG. 17, the operation proceeds to the operation of FIG. 18.

[0089] As shown in FIG. 18 , when the upper cylinder 20 is housed in the lower cylinder 30, the abutment portion 42 overlaps with the slide groove 33 when viewed in the axial direction. When the upper cylinder 20 is housed in the lower cylinder 30, the first convex portion 72 is disposed below the first groove 81 in the other groove structure 80B. When the upper cylinder 20 is housed in the lower cylinder 30, the second convex portion 73 is disposed below the third groove 83 in the other groove structure 80B. When the upper cylinder 20 is housed in the lower cylinder 30, the lower end of the rotation mechanism 40 is disposed inside the lower cylinder 30. After the operation shown in FIG. 18 , the lower end of the rotation mechanism 40 approaches the lower end of the lower cylinder 30. By the above operations, the landing gear 2 is folded and put into the stowed state. Note that the operation of the landing gear 2 to transition from the stowed state to the deployed state is the reverse of the above order (the operation in the order from Figure 18 to Figure 11).

[0090] <One-motion operation of the transmission arm and cylinder mechanism> Figure 19 is a diagram for explaining the one-motion operation of the transmission arm 92 and cylinder mechanism 3 of the embodiment. In Figure 19, the upper part of the page shows "the change over time in the angle of the transmission arm 92 rotating about the first transmission axis D2," the middle part of the page shows "the change over time in the stroke of the cylinder mechanism 3," and the lower part of the page shows "the change over time in the angle of the cylinder mechanism 3 rotating about the first axis C1." In each page, the horizontal axis shows time, indicating the time of one motion (the same time axis in each page).

[0091] 19, changing the angle of the transmission arm 92 in one motion changes the stroke of the cylinder mechanism 3 and also changes the angle of the cylinder mechanism 3. In other words, the cylinder mechanism 3 rotates about the first axis C1 and extends in the axial direction as a result of the driving force being transmitted from the transmission arm 92 in one motion. Through these operations, the landing legs 2 can be switched between the deployed state and the retracted state in one motion.

[0092] <Action and effect> As described above, the landing leg 2 of the aircraft 1 in the above embodiment is the landing leg 2 of the aircraft 1 used when landing, and comprises a first cylinder structure 3A whose upper end is rotatably connected to the aircraft 1, and a second cylinder structure 3B whose lower end can contact the ground, is configured to be movable relative to the first cylinder structure 3A in the axial direction along the reference axis CL, and is configured to be rotatable relative to the first cylinder structure 3A around the reference axis CL, and the first cylinder structure 3A and the second cylinder structure 3B switch the landing leg 2 between a stored state and a deployed state by the relative movement and relative rotation. The landing legs 2 can be switched between a retracted state and an extended state by the relative movement and rotation of the first cylinder structure 3A and the second cylinder structure 3B. Therefore, it is not necessary to manufacture and replace the landing legs 2 every time the aircraft 1 flies. Therefore, it is possible to provide reusable landing legs 2 for the aircraft 1.

[0093] In the above embodiment, the first cylinder structure 3A comprises an upper cylinder 20 whose upper end is rotatably connected to the aircraft 1, and a rotation mechanism 40 provided on the upper cylinder 20 and rotatable around a reference axis CL, while the second cylinder structure 3B comprises a lower cylinder 30 whose lower end is capable of contacting the ground and which is movable axially relative to the upper cylinder 20, and a guide structure 50 provided on the lower cylinder 30 which guides the rotation of the rotation mechanism 40 around the reference axis CL and the movement in the axial direction. According to this configuration, the landing legs 2 can be switched between a retracted state and an extended state by rotating the rotation mechanism 40 about the reference axis line CL relative to the guide mechanism 50 and moving in the axial direction.

[0094] In the above embodiment, the rotation mechanism 40 alternately rotates and moves relative to the guide structure 50 in accordance with the axial movement of the lower cylinder 30, thereby alternately establishing the retracted state and the deployed state of the landing legs 2. The rotation mechanism 40 alternately rotates and moves relative to the guide structure 50, thereby allowing the landing legs 2 to alternate between a retracted state and an extended state.

[0095] In the above embodiment, the lower cylinder 30 comprises a cylindrical lower cylinder body 31 extending along the reference axis CL and a seat portion 32 provided at the upper end of the lower cylinder body 31, and the rotation mechanism 40 comprises a cylindrical rotating cylinder body 41 extending along the reference axis CL and a contact portion 42 provided at the lower end of the rotating cylinder body 41 and contacting the seat portion 32 in the unfolded state. With this configuration, when the landing legs 2 are deployed, the abutment portions 42 of the rotation mechanisms 40 come into contact with the seat portions 32 of the lower cylinders 30, thereby maintaining the deployed state of the landing legs 2. This eliminates the need for a mechanism to maintain the deployed state, making it possible to reduce the weight, size, and cost of the landing legs 2.

[0096] In the above embodiment, the contact portion 42 is released from contact with the seat portion 32 by the rotation of the rotation mechanism 40 . With this configuration, the landing legs 2 can transition from the deployed state to the stowed state by rotating the rotation mechanism 40 and releasing the abutment portions 42 of the rotation mechanism 40 from contact with the seat portions 32. Therefore, there is no need to provide a mechanism for releasing the abutment portions 42 from contact with the seat portions 32. This makes it possible to reduce the weight, size, and cost of the landing legs 2.

[0097] In the above embodiment, the seating surface portions 32 protrude radially inward from the inner periphery of the upper end of the lower cylinder 31 and are provided in multiple locations spaced apart circumferentially of the lower cylinder 31, and the abutment portions 42 protrude radially outward from the outer periphery of the lower end of the rotating cylinder 41 and are provided in multiple locations spaced apart circumferentially of the rotating cylinder 41. With this configuration, the multiple abutment portions 42 abut against the respective seats 32, thereby stably maintaining the deployed state of the landing legs 2. Meanwhile, the landing legs 2 can transition from the deployed state to the stowed state by releasing the abutment portions 42 from the respective seats 32. When transitioning to the stowed state, the abutment portions 42 of the rotating cylinder 41 pass through the circumferential intervals (gaps) between the respective seats 32 of the lower cylinder 31. This prevents the landing legs 2 from expanding radially outward from the lower cylinder 31.

[0098] In the above embodiment, three seating portions 32 are provided and have a three-fold rotationally symmetric shape with respect to the center of the lower cylinder body 31 when viewed from the axial direction, and three abutment portions 42 are provided and have a three-fold rotationally symmetric shape with respect to the center of the rotating cylinder body 41 when viewed from the axial direction. Incidentally, when two each of the seating surfaces 32 and the abutting surfaces 42 are provided (when the central angle is spaced 180° when viewed from the axial direction), the distance over which the rotation mechanism 40 is rotated becomes longer, and the overstroke must be increased accordingly. On the other hand, when four or more each of the seating surfaces 32 and the abutting surfaces 42 are provided, the area of ​​each seating surface 32 and each abutting surface 42 becomes smaller, which may reduce the resistance to loads and impacts during landing. In contrast, with this configuration, three seat portions 32 and three abutment portions 42 are provided in a three-fold symmetrical arrangement, which prevents an increase in overstroke and prevents a decrease in resistance to loads and impacts during landing.

[0099] In the above embodiment, the lower cylinder body 31 has a sliding groove 33 in which the abutment portion 42 can slide, and the sliding groove 33 extends parallel to the axial direction from the upper end to the lower end of the lower cylinder body 31 on the inner circumference of the lower cylinder body 31. With this configuration, when the landing gear 2 is retracted or deployed, the abutment portion 42 at the lower end of the rotating cylinder 41 can be moved parallel to the axial direction along the sliding groove 33 on the inner periphery of the lower cylinder 31. Therefore, the rotation mechanism 40 can be moved stably relative to the lower cylinder 30. In addition, if the rotation mechanism 40 is attached to the tip of the rod 62 of the shock absorber 60, swinging of the rotation mechanism 40 can be suppressed. Therefore, deterioration of the shock absorber 60 can be suppressed.

[0100] In the above embodiment, the guide structure 50 is provided axially closer to the upper end of the upper cylinder 20 than the seat portion 32, and includes a cylindrical guide cylinder 51 along the reference axis CL, and a plurality of groove structures 80 periodically arranged circumferentially on the inner circumference of the guide cylinder 51, and the rotation mechanism 40 includes a cylindrical rotating cylinder 41 along the reference axis CL, and a plurality of convex structures 70 periodically arranged circumferentially on the outer periphery of the rotating cylinder 41. According to this configuration, the periodic groove structure 80 of the guide structure 50 and the periodic convex structure 70 of the rotation mechanism 40 cooperate to allow the rotation mechanism 40 to alternately rotate and move relative to the guide structure 50. This eliminates the need for a mechanism that applies power to operate the rotation mechanism 40. This makes it possible to reduce the weight, size, and cost of the landing leg 2.

[0101] In the above embodiment, the groove structure 80 comprises a first groove 81 extending parallel to the axial direction from the upper end to the lower end of the guide cylinder 51, a second groove 82 extending from halfway along the first groove 81 towards the upper end of the guide cylinder 51 at an angle with respect to the axial direction and opening at the upper end of the guide cylinder 51, and a third groove 83 located closer to the lower end of the guide cylinder 51 than the second groove 82, extending from halfway along the first groove 81 towards the lower end of the guide cylinder 51 at an angle with respect to the axial direction and opening at the lower end of the guide cylinder 51, and the convex structure 70 comprises an extending portion 71 extending parallel to the axial direction from the upper end to the lower end of the rotating cylinder 41, and a first convex portion 72 and a second convex portion 73 protruding from the extending portion 71 radially outward of the rotating cylinder 41 and arranged at a distance from each other in the circumferential and axial directions of the rotating cylinder 41 so as to be slidable into any of the first groove 81, the second groove 82, and the third groove 83. According to this configuration, the first groove 81, the second groove 82, and the third groove 83 of the groove structure 80 cooperate with the first convex portion 72 and the second convex portion 73 of the convex structure 70, allowing the rotation mechanism 40 to alternately rotate and move relative to the guide structure 50. This eliminates the need for a mechanism that applies power to operate the rotation mechanism 40. This makes it possible to reduce the weight, size, and cost of the landing leg 2. In addition, because the second groove 82 and the third groove 83 are inclined relative to the first groove 81, the axial movement of the lower cylinder 30 can be smooth, and the landing leg 2 can be smoothly retracted and deployed.

[0102] In the above embodiment, a shock absorber 60 is housed inside the upper cylinder 20, and the shock absorber 60 has a rod 62 that extends along the axial direction and is rotatable around the reference axis line CL, and the rotation mechanism 40 is attached to the tip of the rod 62. With this configuration, shock absorber 60 can absorb the impact during landing that is transmitted from the upper end of lower cylinder 30 to the lower end of rotation mechanism 40. In addition, because rod 62 of shock absorber 60 is rotatable about reference axis line CL and rotation mechanism 40 is attached to the tip of rod 62, there is no need to provide a mechanism for rotating rotation mechanism 40. This makes it possible to reduce the weight, size, and cost of landing leg 2.

[0103] In the above embodiment, the lower beam 90 has a first end that is rotatably connected to the aircraft 1 and a second end that is rotatably connected to the lower cylinder 30. With this configuration, when the landing gear 2 is alternately retracted and deployed, the lower beam 90 can stably support the lower cylinder 30. For example, when the aircraft 1 is flying, the landing gear 2 can be compactly retracted by bringing the lower beam 90 close to the aircraft 1 and moving the lower cylinder 30 toward the upper end of the upper cylinder 20. For example, when the aircraft 1 is landing, the aircraft 1 can be stabilized by positioning the lower end of the lower cylinder 30 away from the aircraft 1.

[0104] In the above embodiment, a pair of lower beams 90 are provided so that their first ends are connected to two points on the aircraft 1, and between the pair of lower beams 90 are provided an actuator 91 that drives the landing legs 2 and a transmission arm 92 that transmits the driving force of the actuator 91 to the lower cylinder 30. With this configuration, the load that is applied when the lower end of the lower cylinder 30 comes into contact with the ground while the landing gear 2 is deployed can be borne by the transmission arm 92. This reduces the burden on other parts during landing. For example, a structure can be realized in which the transmission arm 92 absorbs the landing load, thereby protecting the actuator 91. However, if the actuator 91 is attached to each of the pair of lower beams 90, the actuator 91 will need to absorb the impact during landing, which could result in the actuator 91 becoming larger. In contrast, according to this embodiment, the actuator 91 is provided between the pair of lower beams 90 (specifically, connected to the lower beams 90 via the transmission arm 92), so the actuator 91 only needs to have the driving force to drive the landing legs 2. Therefore, the actuator 91 can be made smaller, and costs can also be reduced.

[0105] In the above embodiment, the actuator 91 is surrounded by the aircraft 1, the lower cylinder 30, and the pair of lower beams 90 in the stored state. With this configuration, the actuator 91 in the stowed state can be protected from external factors by the aircraft 1, the lower cylinder 30, and the pair of lower beams 90. For example, when the landing gear 2 is folded, the landing gear 2 covers the actuator 91 while the aircraft 1 is flying, thereby preventing wear on the actuator 91. However, if components such as the actuator 91 protrude significantly radially outward from the aircraft 1 when the landing gear 2 is retracted, this could reduce the aerodynamic performance of the aircraft 1. In contrast, according to this embodiment, the actuator 91 is surrounded by the aircraft 1, the lower cylinder 30, and the pair of lower beams 90 when the landing gear 2 is retracted, thereby minimizing the radial outward protrusion of the components from the aircraft 1. Therefore, the reduction in the aerodynamic performance of the aircraft 1 can be minimized.

[0106] In the above embodiment, when the landing gear 2 transitions from the deployed state to the stowed state, the lower beam 90 is actuated in a direction away from the aircraft 1. According to this configuration, the direction in which the lower beam 90 is moved away from the aircraft 1 is the direction in which the lower end of the rotation mechanism 40 moves away from the upper end of the lower cylinder 30. Therefore, the rotation mechanism 40 can be operated without applying excessive force to the lower end of the rotation mechanism 40. Therefore, the rotation mechanism 40 can be operated smoothly.

[0107] <Modification> In the above embodiment, an example has been described in which the first cylinder structure includes an upper cylinder whose upper end is rotatably connected to the aircraft and a rotation mechanism attached to the upper cylinder and rotatable around a reference axis, and the second cylinder structure includes a lower cylinder whose lower end is capable of contacting the ground and which is movable axially relative to the upper cylinder, and a guide structure attached to the lower cylinder for guiding the rotation of the rotation mechanism around the reference axis and its movement in the axial direction. However, this is not limited to this. For example, the first cylinder structure may not include an upper cylinder and a rotation mechanism. For example, the first cylinder structure may include a lower cylinder and a guide structure. For example, the second cylinder structure may not include a lower cylinder and a guide structure. For example, the second cylinder structure may include an upper cylinder and a rotation mechanism. For example, the first cylinder structure may include one of the upper cylinder or the lower cylinder and one of the rotation mechanism or the guide structure, and the second cylinder structure may include the other of the upper cylinder or the lower cylinder and the other of the rotation mechanism or the guide mechanism. For example, the configuration of the first cylinder structure and the second cylinder structure can be changed according to required specifications.

[0108] In the above embodiment, the rotation mechanism alternately rotates and moves relative to the guide structure in accordance with the axial movement of the lower cylinder, thereby alternately establishing the retracted and deployed states of the landing gear. However, this is not limiting. For example, the rotation mechanism does not have to alternately rotate and move relative to the guide structure in accordance with the axial movement of the lower cylinder. For example, the retracted and deployed states of the landing gear may be switched by rotating the rotation mechanism about a reference axis and axially moving it relative to the guide structure. For example, the retracted and deployed states of the landing gear may be switched by relative movement and rotation between the first cylinder structure and the second cylinder structure. For example, the manner of relative movement and relative rotation may be changed according to required specifications.

[0109] In the above embodiment, the lower cylinder includes a cylindrical lower cylinder body along the reference axis and a seat portion provided at the upper end of the lower cylinder body, and the rotation mechanism includes a cylindrical rotating cylinder body along the reference axis and a contact portion provided at the lower end of the rotating cylinder and contacting the seat portion in the deployed state. However, this is not limited to this. For example, the lower cylinder may not include a seat portion. For example, the rotation mechanism may not include a contact portion. For example, a mechanism for maintaining the deployed state of the landing gear may be provided. For example, the configuration for maintaining the deployed state of the landing gear may be changed depending on required specifications.

[0110] In the above embodiment, an example has been described in which the contact portion is released from contact with the seat portion by rotation of the rotation mechanism, but this is not limited thereto. For example, the contact portion does not have to be released from contact with the seat portion by rotation of the rotation mechanism. For example, a mechanism for releasing the contact of the contact portion with the seat portion may be provided. For example, the configuration for releasing the contact of the contact portion with the seat portion can be changed according to required specifications.

[0111] In the above embodiment, an example has been described in which the seating surface portions protrude radially inward from the inner periphery at the upper end of the lower cylindrical body and are provided at intervals around the circumferential direction of the lower cylindrical body, and the abutting portions protrude radially outward from the outer periphery at the lower end of the rotating cylindrical body and are provided at intervals around the circumferential direction of the rotating cylindrical body. However, this is not limited to this. For example, the seating surface portions do not have to protrude radially inward from the inner periphery at the upper end of the lower cylindrical body. For example, the seating surface portions do not have to be provided at intervals around the circumferential direction of the rotating cylindrical body. For example, the abutting portions do not have to protrude radially outward from the outer periphery at the lower end of the rotating cylindrical body. For example, the abutting portions do not have to be provided at intervals around the circumferential direction of the rotating cylindrical body. For example, the arrangement of the seating surface portions and the abutting portions can be changed according to required specifications.

[0112] In the above embodiment, an example has been described in which three seating portions are provided and have a three-fold rotationally symmetric shape with respect to the center of the lower cylinder when viewed in the axial direction, and three abutting portions are provided and have a three-fold rotationally symmetric shape with respect to the center of the rotating cylinder when viewed in the axial direction, but this is not limited to this. For example, two seating portions and two abutting portions may be provided. For example, four or more seating portions and four or more abutting portions may be provided. For example, the number of seating portions and two abutting portions provided may be changed depending on the required specifications.

[0113] In the above embodiment, the lower cylinder body has a sliding groove along which the abutment portion can slide, and the sliding groove extends parallel to the axial direction on the inner periphery of the lower cylinder body from the upper end to the lower end of the lower cylinder body. However, this is not limited to this. For example, the sliding groove does not have to extend parallel to the axial direction on the inner periphery of the lower cylinder body from the upper end to the lower end of the lower cylinder body. For example, the sliding groove may extend parallel to the axial direction on the inner periphery of the lower cylinder body from the upper end to partway toward the lower end of the lower cylinder body. For example, the lower cylinder body does not have to have a sliding groove. For example, the arrangement of the sliding groove can be changed depending on the required specifications.

[0114] In the above embodiment, the guide structure is provided axially closer to the upper end of the upper cylinder than the seat portion and includes a cylindrical guide cylinder along the reference axis and a plurality of groove structures periodically arranged in the circumferential direction on the inner circumference of the guide cylinder. The rotation mechanism includes a cylindrical rotating cylinder along the reference axis and a plurality of convex structures periodically arranged in the circumferential direction on the outer circumference of the rotating cylinder. However, this is not limited to this. For example, the guide structure does not need to include a periodic groove structure. For example, the rotation mechanism does not need to include a periodic convex structure. For example, a mechanism for applying power to operate the rotation mechanism may be provided. For example, the configurations of the guide structure and the rotation mechanism can be changed according to required specifications.

[0115] In the above embodiment, an example has been described in which the convex portion of the rotation mechanism provided on the upper cylinder is guided along the groove of the guide structure provided on the lower cylinder, but this is not limited thereto. For example, the rotation mechanism provided on the upper cylinder may have a groove in the rotating barrel, and the guide structure provided on the lower cylinder may have a convex portion (e.g., a convex portion that does not rotate around the reference axis). For example, the convex portion of the guide structure provided on the lower cylinder may be configured to be guided along the groove of the rotation mechanism provided on the upper cylinder. For example, the configuration of the convex portion and groove of the rotation mechanism and the guide structure may be changed according to required specifications.

[0116] In the above embodiment, the groove structure includes a first groove extending parallel to the axial direction from the upper end to the lower end of the guide cylinder, a second groove extending from the middle of the first groove toward the upper end of the guide cylinder at an angle relative to the axial direction and opening at the upper end of the guide cylinder, and a third groove located closer to the lower end of the guide cylinder than the second groove, extending from the middle of the first groove toward the lower end of the guide cylinder at an angle relative to the axial direction and opening at the lower end of the guide cylinder. The convex structure includes an extending portion extending parallel to the axial direction from the upper end to the lower end of the rotating cylinder, and a first convex portion and a second convex portion protruding from the extending portion radially outward from the rotating cylinder and spaced apart from each other in the circumferential and axial directions of the rotating cylinder so as to be slidable in any of the first, second, and third grooves. However, the present invention is not limited to this. For example, the groove structure may not include the first, second, and third grooves. For example, the convex structure may not include the first and second convex portions. For example, the convex structure may not have an extension portion. For example, a mechanism for applying power to operate the rotation mechanism may be provided. For example, the configuration of the groove structure and the convex structure may be changed according to required specifications.

[0117] In the above embodiment, an example has been described in which a shock absorber is housed inside the upper cylinder, the shock absorber includes a rod that extends axially and is rotatable about a reference axis, and the rotation mechanism is attached to the tip of the rod. However, this is not limiting. For example, the shock absorber does not have to be housed inside the upper cylinder. For example, the shock absorber may be provided outside the upper cylinder. For example, the rotation mechanism does not have to be attached to the tip of the rod. For example, a mechanism for rotating the rotation mechanism may be provided. For example, the installation manner of the shock absorber and the rotation mechanism can be changed according to required specifications.

[0118] In the above embodiment, an example has been described in which the upper cylinder is disposed closer to the aircraft than the lower cylinder in the axial direction along the reference axis when the landing gear is deployed, but this is not limiting. For example, when the landing gear is deployed, the lower cylinder may be disposed closer to the aircraft than the upper cylinder in the axial direction along the reference axis. For example, the positions of the upper cylinder and the lower cylinder may be reversed in the axial direction along the reference axis. For example, the shock absorber may be attached to the lower cylinder. For example, the shock absorber may be attached to the transmission arm. For example, the positions of the upper cylinder and the lower cylinder in the axial direction along the reference axis and the installation mode of the shock absorber can be changed according to required specifications.

[0119] In the above embodiment, an example was described in which a lower beam has a first end rotatably connected to the aircraft and a second end rotatably connected to the lower cylinder, but this is not limiting. For example, the landing gear does not necessarily have to have a lower beam. For example, the installation mode of the lower beam can be changed depending on the required specifications.

[0120] In the above embodiment, a pair of lower beams are provided such that the first ends are connected to two locations on the aircraft, and an actuator that drives the landing gear and a transmission arm that transmits the driving force of the actuator to the lower cylinder are provided between the pair of lower beams. However, this is not limiting. For example, the pair of lower beams does not have to be provided. For example, only one lower beam may be provided. For example, three or more lower beams may be provided. For example, the actuator and the transmission arm do not have to be provided between the pair of lower beams. For example, the installation mode of the actuator and the transmission arm can be changed according to required specifications.

[0121] In the above embodiment, the actuator is surrounded by the flying vehicle, the lower cylinder, and the pair of lower beams in the stowed state, but this is not limiting. For example, the actuator does not have to be surrounded by the flying vehicle, the lower cylinder, and the pair of lower beams in the stowed state. For example, the arrangement of the actuator in the stowed state can be changed according to required specifications.

[0122] In the above embodiment, an example has been described in which the lower beam is actuated in a direction away from the aircraft when the landing gear transitions from the deployed state to the stowed state, but this is not limited to this. For example, the lower beam does not have to be actuated in a direction away from the aircraft when the landing gear transitions from the deployed state to the stowed state. For example, the lower beam may be actuated in a direction opposite to the direction away from the aircraft when the landing gear transitions from the deployed state to the stowed state. For example, the actuation mode when the landing gear transitions from the deployed state to the stowed state can be changed according to required specifications.

[0123] The above describes preferred embodiments of the present invention, but the present invention is not limited to these, and additions, omissions, substitutions, and other modifications to the configuration are possible within the scope of the spirit of the present invention, and the above-mentioned modifications can also be combined as appropriate. [Explanation of symbols]

[0124] 1...Flying object 2...Landing legs 3A...First cylinder structure 3B...Second cylinder structure 20...Upper cylinder 30...Lower cylinder 31...Lower cylinder 32... Seat part 33...Sliding groove 40...Rotation mechanism 41...Rotating cylinder 42...Abutting part 50...Guide structure 51...Guide cylinder 60...Shock absorber 62...Rod 70…Convex structure 71...Extension part 72...First convex part 73...Second convex part 80…Groove structure 81…1st groove 82…Second groove 83…3rd groove 90...Lower beam 91...Actuator 92...Transmission arm CL…Reference axis line

Claims

1. A landing gear of an aircraft used when landing, a first cylinder structure whose upper end is rotatably connected to the flying body; a second cylinder structure, the lower end of which is capable of contacting the ground, configured to be movable relative to the first cylinder structure in an axial direction along a reference axis, and configured to be rotatable relative to the first cylinder structure around the reference axis; the first cylinder structure and the second cylinder structure switch the landing legs between a retracted state and a deployed state by the relative movement and the relative rotation; The landing gear of an aircraft.

2. The first cylinder structure is an upper cylinder whose upper end is rotatably connected to the flying body; a rotation mechanism provided in the upper cylinder and rotatable around the reference axis, The second cylinder structure is a lower cylinder having a lower end capable of contacting the ground and movable in the axial direction relative to the upper cylinder; a guide structure provided in the lower cylinder to guide the rotation of the rotation mechanism about the reference axis and the movement in the axial direction, The landing gear of claim 1.

3. the rotation mechanism alternately repeats the rotation and the movement relative to the guide structure in accordance with the movement of the lower cylinder in the axial direction, thereby alternately establishing a retracted state and an extended state of the landing gear. The landing gear of claim 2.

4. The lower cylinder is a cylindrical lower cylinder body extending along the reference axis; a seat portion provided at an upper end of the lower cylinder body, The rotation mechanism includes: a cylindrical rotating cylinder extending along the reference axis; a contact portion provided at a lower end of the rotating cylinder and contacting the seat portion in the deployed state, The landing gear of an aircraft according to claim 2 or 3.

5. The abutment portion is released from contact with the seat portion by the rotation of the rotation mechanism. The landing gear of an aircraft. The landing gear of claim 4.

6. the seating surface portion protrudes radially inward from an inner periphery of an upper end of the lower cylindrical body, and is provided in plurality at intervals in a circumferential direction of the lower cylindrical body; The abutment portions protrude radially outward from the outer periphery of the lower end of the rotating cylindrical body, and are provided in plurality at intervals in the circumferential direction of the rotating cylindrical body. The landing gear of an aircraft according to claim 4 or 5.

7. the seating surface portions are provided in three numbers, and have a rotationally symmetric shape that is three-fold symmetric with respect to the center of the lower cylinder body when viewed in the axial direction, The abutment portions are provided in three numbers, and have a rotationally symmetric shape with three rotations about the center of the rotating cylindrical body when viewed in the axial direction. The landing gear of claim 6.

8. the lower cylinder body has a slide groove along which the abutment portion can slide, The sliding groove extends parallel to the axial direction on the inner periphery of the lower cylindrical body from the upper end to the lower end of the lower cylindrical body. The landing gear of an air vehicle according to any one of claims 4 to 7.

9. The lower cylinder is a cylindrical lower cylinder body extending along the reference axis; a seat portion provided at an upper end of the lower cylinder body, The guide structure includes: a cylindrical guide cylinder body that is provided on an upper end side of the upper cylinder relative to the seating surface portion in the axial direction and that extends along the reference axis; a plurality of groove structures periodically provided in the circumferential direction on the inner periphery of the guide cylindrical body, The rotation mechanism includes: a cylindrical rotating cylinder extending along the reference axis; a plurality of convex structures provided periodically in the circumferential direction on the outer periphery of the rotating cylindrical body, A landing gear for an air vehicle according to any one of claims 2 to 8.

10. The groove structure is a first groove extending parallel to the axial direction from an upper end to a lower end of the guide cylinder; a second groove extending from a middle of the first groove toward an upper end of the guide cylinder at an angle with respect to the axial direction and opening at the upper end of the guide cylinder; a third groove that is provided closer to the lower end of the guide cylinder than the second groove, extends from a midpoint of the first groove toward the lower end of the guide cylinder at an angle with respect to the axial direction, and opens at the lower end of the guide cylinder, The convex structure is an extension portion extending parallel to the axial direction from an upper end to a lower end of the rotary cylindrical body; a first convex portion and a second convex portion that protrude from the extending portion radially outward of the rotating cylindrical body, are slidable in any one of the first groove, the second groove, and the third groove, and are provided at intervals from each other in the circumferential direction and the axial direction of the rotating cylindrical body, The landing gear of claim 9.

11. A shock absorber is housed inside the upper cylinder, the shock absorber includes a rod extending along the axial direction and rotatable around the reference axis; The rotation mechanism is attached to the tip of the rod. A landing gear for an air vehicle according to any one of claims 2 to 10.

12. a lower beam having a first end rotatably connected to the flying body and a second end rotatably connected to the lower cylinder; A landing gear for an air vehicle according to any one of claims 2 to 11.

13. a pair of lower beams are provided such that the first ends are connected to two locations of the aircraft; Between the pair of lower beams, an actuator for driving the landing legs; a transmission arm that transmits the driving force of the actuator to the lower cylinder, The landing gear of claim 12.

14. In the stored state, the actuator is surrounded by the flying vehicle, the lower cylinder, and the pair of lower beams. The landing gear of claim 13.

15. When the landing gear is transitioned from the deployed state to the stowed state, the lower beam is actuated in a direction away from the aircraft. A landing gear for an air vehicle according to any one of claims 12 to 14.

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