Combined retractable motion landing gear and aircraft thus equipped.

Abstract

Retractable aircraft landing gear, comprising: a main connecting piece of the landing gear to the aircraft arranged to pivot about a first principal axis of rotation substantially parallel to a longitudinal direction of the aircraft; a leg having one end fitted with a wheel and at the opposite end a box having an upper portion connected to the main connecting piece to pivot about a second principal axis of rotation substantially perpendicular to the first principal axis of rotation; a leg displacement / stabilization mechanism for moving the leg between a deployed position and a retracted position by simultaneous rotation of the leg about the principal axes of rotation, the displacement / stabilization mechanism comprising a strut for bracing the leg in the deployed position and a guide rod for guiding the rotation of the leg about the principal axes of rotation. [Fig. 4]

Description

Title of the invention: Combined retracting motion lander and aircraft thus equipped.

[0001] The present invention relates to the field of aeronautics and more particularly to that of landing gear.

[0002] BACKGROUND OF THE INVENTION

[0003] Commonly, current aircraft intended for the transport of cargo or people have a nose landing gear, mounted under the nose of the aircraft and equipped with a pair of wheels, and main landing gear mounted under the fuselage or wings of the aircraft and equipped with several pairs of wheels. During flight, each landing gear is raised and folded into a landing gear bay integrated into the fuselage or wings, in order to improve the aircraft's aerodynamics by reducing drag.

[0004] The stability of the aircraft in turns during taxiing and the ground clearance required for the aircraft structure (for example at the level of the engines) determine the spacing of the wheels of the main landing gear and the position of the wheels relative to the attachments of the main landing gear to the aircraft structure.

[0005] Landers are arranged to perform a lifting movement along one or more axes of rotation. In the simplest cases, a single-axis solution is used, and the landing gear housing must be large enough to accommodate the entire length of the landing gear (the length corresponding to the height of the deployed landing gear). Since landing gear usually folds forward on the aircraft, this solution results either in a rearward positioning of the landing gear attachment point on the aircraft structure, interfering with the aerodynamic fairings (belly fairing or ventral fairing), or in the impossibility of integrating the wheels into the fuselage.

[0006] Other landing gear lifting configurations that cause the landing gear to retract in order to limit their size in the cargo hold exist but are very complex and not very compatible with certain aircraft structures.

[0007] SUBJECT OF THE INVENTION

[0008] The invention relates in particular to providing a retractable aircraft landing gear having a structure that optimizes its size within the fuselage. Summary of the invention

[0009] To this end, the invention provides a retractable aircraft landing gear comprising: - a main connecting part of the lander to the aircraft arranged to pivot around a first main axis of rotation substantially parallel to a longitudinal direction of the aircraft; - a leg having one end fitted with a wheel and at the opposite end a box having an upper part connected to the main connecting piece to pivot around a second main axis of rotation substantially perpendicular to the first main axis of rotation; - a leg displacement / stabilization mechanism for moving the leg between a deployed position and a retracted position by a simultaneous rotation of the leg around the principal axes of rotation, the displacement / stabilization mechanism comprising a strut for bracing the leg in the deployed position and a guide rod to guide the rotation of the leg around the principal axes of rotation, the strut comprising a first rod and a second rod linked to each other by an intermediate joint and having a first end provided with a joint for connection to the aircraft structure and a second end provided with a joint for connection to the box section,The joint connecting to the aircraft structure is arranged to rotate relative to the aircraft structure around a first secondary axis of rotation and to rotate relative to the intermediate joint around a second secondary axis of rotation coinciding with a longitudinal direction of the first connecting rod. The connecting rod has a first end connected to the aircraft structure and a second end connected to a lower part of the landing gear box.

[0010] Thus, the landing gear retracts and deploys by rotating around two axes of rotation simultaneously. The housing for the landing gear can then be of relatively small dimensions and in a position better suited to the aircraft structure, i.e., better respecting the fuselage profile.

[0011] According to optional features, used individually or in whole or in combination: - the box is juxtaposed to the main connecting piece when the lander is in the retracted position; - the first connecting rod and the second connecting rod of the counter brace are capable of being locked in an alignment position by a constraint element; - the wheel has a rolling axis that is substantially vertical when the leg is in the retracted position; - the retraction / stabilization mechanism includes an operating cylinder; - the operating cylinder includes an end for connecting to the structure of the aircraft and one end of the connection to the caisson; - the leg includes a rocker arm articulated at one end of the box opposite the connecting piece, the rocker arm having a free end carrying an axle on which the wheel is fixed.

[0012] The invention also provides for an aircraft equipped with at least one such landing system.

[0013] Optionally, the lander is mounted to deploy in a direction opposite to the direction of travel of the aircraft.

[0014] Other features and advantages of the invention will become apparent from the following description of a particular, non-limiting embodiment of the invention. Brief description of the drawings

[0015] Reference will be made to the attached drawings, among which:

[0016] [Fig-1] is a general front view of an aircraft according to the invention;

[0017] [Fig.2] is a schematic perspective view of a part of the aircraft illustrated in the [Fig.l];

[0018] [Fig.3] is a general perspective view of a landing gear according to the invention equipping the aircraft illustrated in Figures 1 and 2, the landing gear being in the process of being deployed / retracted;

[0019] [Fig. 4a] is a side view of the deployed lander shown in [Fig.3];

[0020] [Fig. 4b] is a front view of this deployed lander;

[0021] [Fig. 4c] is a side view of the same lander but retracted into a housing of the aircraft;

[0022] [Fig. 4d] is a front view of this lander retracted into this housing;

[0023] [Fig. 5a] is a perspective view of the deployed lander;

[0024] [Fig. 5b] is a perspective view of the lander in an intermediate position during its movement of retraction or deployment;

[0025] [Fig. 5c] is a perspective view of the lander in the retracted position. DETAILED DESCRIPTION OF THE INVENTION

[0026] With reference to Figures 1 and 2, the invention is described in application to an aircraft 100 comprising a fuselage 101 from which two main landing gear 1 extend. Each landing gear 1 has a leg having one end articulated to the structure of the aircraft 100 and, at the opposite end, a free end provided with an axle on which wheels 2 are pivotally mounted. The landing gear 1 is arranged so that it can be raised and retracted to reduce its size when not in use. The structure of the aircraft 100 includes openings giving access to compartments (or bays) 102 formed in a lower part of the fuselage 101 and each capable of housing one of the retracted landing gear 1. These compartments 102 allow the landing gear 1 to be integrated inside the fuselage 101 so as not to not degrade the aerodynamic performance of aircraft 100 in flight. The lower part of the fuselage 101 located under aircraft 100 is an aerodynamic fairing commonly called a "bell fairing".

[0027] With reference to [Fig.3], the lander 1 comprises a main connecting piece 3, a box 4, a pendulum 5 and a damper 6.

[0028] The main connecting piece 3 is rotationally connected on one side to the structure of the aircraft 100 along a first principal axis of rotation XI, and on the other side to an upper part or upper end 4.1 of the box 4, along a second principal axis of rotation X2. The principal axis of rotation XI is substantially parallel to a longitudinal direction of the aircraft 100, and the principal axis of rotation X2 is substantially perpendicular to the principal axis of rotation XL

[0029] The rocker arm 5 has a first end 5.1 linked by pivot to a lower part or lower end 4.2 of the box 4 to pivot about an axis parallel to the main axis of rotation XI, and a second free end 5.2 on which is mounted the axle carrying the wheels 2. The box 4 and the rocker arm 5 form a leg of the lander 1.

[0030] The damper 6 has a first end articulated to the main connecting piece 3 to pivot around the second main axis of rotation X2 and a second end articulated to the second end 5.2 of the rocker 5. The damper 6 is arranged so as to dampen the vertical forces exerted on the wheel 2.

[0031] The lander 1 includes a leg displacement / stabilization mechanism for moving the leg between a deployed position and a retracted position by a simultaneous rotation of the leg around the principal axes of rotation XI, X2.

[0032] The displacement / stabilization mechanism includes a brace 7 to brace the leg in the deployed position and a steering rod 10 to guide the rotation of the leg around the main axes of rotation XI and X2.

[0033] The strut 7 comprises a first connecting rod 7.1 and a second connecting rod 7.2 linked to each other by an intermediate joint. The first connecting rod 7.1 has a first end 7.1.1 rotationally connected to a yoke 7.3 along a first secondary axis of rotation X3 aligned with a longitudinal direction of the first connecting rod 7.1, the yoke 7.3 being pivotally connected to the aircraft structure 100 to pivot about a second secondary axis of rotation X4 perpendicular to the first secondary axis of rotation X3, and a second end 7.1.2 pivotally connected to a first end 7.2.1 of the second connecting rod 7.2. The second connecting rod 7.2 has a second end 7.2.2 pivotally connected to the lower end 4.2 of the box 4.The two strut connecting rods are movable relative to each other between a folded position (retracted position of lander 1) and an aligned position providing bracing for lander 1 (deployed position of lander 1). The . The displacement / stabilization mechanism includes a hinged constraint element 8 having at least one lever 8.1, a spring 8.2, and a stop 8.3. The constraint element 8 is positioned between the second connecting rod 7.2 and the box 4. The spring 8.2 applies a press force to the stop 8.3 during the alignment of the connecting rods 7.1 and 7.2 of the strut 7, thus locking the alignment of the two connecting rods 7.1 and 7.2. Unlocking the alignment of the connecting rods 7.1 and 7.2 of the strut 7 is performed in a manner known per se by an auxiliary actuator not shown here.

[0034] The guide rod 10 has a first end connected to the aircraft structure 100 and a second end connected to the lower part of the housing 4. This guide rod 10 allows, on the one hand, the transmission of the loads supported by the landing gear 1 to the aircraft structure 100 and, on the other hand, the guidance of the landing gear leg 1 during its retraction and deployment. A modification in the dimensions or positioning of this guide rod 10 then makes it possible to easily modify and adjust the trajectory of the landing gear leg 1 during its deployment or retraction.

[0035] The displacement / stabilization mechanism has a tandem cylinder 9 for maneuvering the leg. The actuator 9 has a first end 9.1 articulated to the aircraft structure 100 and a second end 9.2 articulated to the upper end 4.1 of the box 4. Retracting the actuator 9 allows the landing gear 1 to fold inside the housing 102 of the fuselage 101, and extending the actuator 9 allows the landing gear 1 to deploy. During the deployment of the landing gear 1, the actuator 9 applies a thrust force to the box 4, said box 4 undergoing a simultaneous rotational movement around the main axis of rotation XI and the main axis of rotation X2, this movement being guided by the steering rod 10. The deployment of the landing gear 1 allows the two connecting rods 7.1 and 7.2 of the strut 7 to align, the constraint element 8 locking the strut in its aligned position.

[0036] During the retraction of the lander 1, the auxiliary actuator unlocks the articulated constraint element 8, making possible the movement between the two connecting rods 7.1 and 7.2 of the counter brace 7, and the cylinder 9 retracts, allowing the box 4 to perform the reverse movement of that performed during its deployment, along the two main axes of rotation XI and X2.

[0037] This rotation allows the wheels 2 to be positioned horizontally (the rolling axis of the wheels 2 being substantially vertical) inside the housing 102, as illustrated in Figures 4c and 4d. This arrangement of the wheels 2 inside the fuselage 101 significantly limits the height of said wheels 2 in the housing 102, as the side of one of the wheels 2 can be positioned very close to an internal wall of the lower part of the aerodynamic fairing.

[0038] The retracted landing gear 1 occupies a space with a reduced overall length within the fuselage 101. Indeed, with reference to figures 5a, 5b and 5c, the movement of the landing gear 1 along the two main axes of rotation XI and X2 allows the box 4 to be positioned juxtaposed to the main connecting piece 3, and not aligned with it as in the deployed position of the landing gear 1.

[0039] Landing gear 1, occupying less space when folded, allows for greater flexibility in positioning the connection point between said landing gear 1 and the aircraft structure 100 during aircraft design. Consequently, a more forward positioning of said connection point between landing gear 1 and the aircraft structure 100 enables the landing gear 1 to be folded and deployed towards the rear of the aircraft 100. This rearward movement may be necessary in certain aircraft configurations.

[0040] Of course, the invention is not limited to the embodiment described but encompasses any variant falling within the scope of the invention as defined by the claims.

[0041] In particular, although here the landing gear 1 has a type of rocker-arm damping and a pair of wheels 2 in a "diabolo" shape, the invention is applicable to other types of landing gear such as direct-damping gear for example and / or having a different number of wheels (single-wheel, bogie...).

[0042] Although here the two-degree-of-freedom joints are characterized by clevises rotating along two axes of rotation perpendicular to each other, it is possible that this solution could be replaced by another technical solution such as a ball joint for example.

[0043] The first end 7.1.1 of the first connecting rod 7.1 forming a yoke 7.3 for connecting to the aircraft structure 100 of the strut 7 can be arranged to rotate relative to the intermediate joint around the secondary axis of rotation X3 as described above, or this first end 7.1.1 can be one piece with the first connecting rod 7.1, the intermediate joint being mounted on the second end 7.1.2 of the first connecting rod 7.1 to pivot around the secondary axis of rotation X3.

[0044] Although here the operating cylinder 9 is of the tandem type, it is possible that the cylinder is of another type such as a double-acting, single-acting, double-rod cylinder or of another type of hydraulic or pneumatic actuator.

Claims

Demands

1. Retractable landing gear for aircraft (100), comprising: - a main connecting piece (3) of the landing gear to the aircraft (100) arranged to pivot about a first principal axis of rotation (XI) substantially parallel to a longitudinal direction of the aircraft (100); - a leg having one end provided with a wheel (2) and at the opposite end a box (4) having an upper part (4.1) linked to the main connecting piece (3) to pivot about a second main axis of rotation (X2) substantially perpendicular to the first main axis of rotation (XI); - a leg displacement / stabilization mechanism to move the leg between a deployed position and a retracted position by a simultaneous rotation of the leg about the main axes of rotation (XI, X2), the displacement / stabilization mechanism comprising a brace (7) for bracing the leg in the deployed position and a guide rod (10) to guide the rotation of the leg about the main axes of rotation (XI and X2), the brace comprising a first rod (7.1) and a second rod (7.2) linked to each other by an intermediate joint and having a first end provided with a joint for connecting to the aircraft structure (100) and a second end provided with a joint for connecting to the box (4), the joint for connecting to the aircraft structure (100) being arranged to rotate relative to the aircraft structure around a first secondary axis of rotation (X4) and to rotate relative to the intermediate joint around a second secondary axis of rotation (X3) coinciding with a longitudinal direction of the first connecting rod (7.1), the guiding connecting rod having a first end for connecting to the aircraft structure (100) and a second end for connecting to a lower part (4.2) of the box (4).

2. Lander according to claim 1, wherein the box (4) is juxtaposed to the main connecting piece (3) when the lander is in the retracted position.

3. Land according to claim 1 or 2, wherein the first connecting rod and the second connecting rod of the counter strut (7) are able to be locked in an alignment position by a constraint element (8).

4. Land according to any one of the preceding claims, wherein the wheel (2) has a substantially vertical rolling axis when the leg is in the retracted position.

5. Lander according to any one of the preceding claims, wherein the retraction / stabilization mechanism includes a maneuvering cylinder (9).

6. Lander according to claim 5, wherein the maneuvering cylinder (9) comprises an end for connecting to the aircraft structure (100) and an end for connecting to the box (4).

7. Lander according to any one of the preceding claims, wherein the leg comprises a rocker arm (5) hinged to one end of the box (4) opposite the connecting piece, the rocker arm having a free end carrying an axle on which the wheel is fixed.

8. Aircraft comprising a structure to which is attached at least one landing gear (1) according to one of the preceding claims.

9. Aircraft according to claim 8, wherein the landing gear is mounted to deploy in a direction opposite to the direction of forward movement of the aircraft (100).

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