FR3078943A1 - METHOD FOR MANEUVERING AN AIRCRAFT ENGINEER BETWEEN A DEPLOYED POSITION AND A RETRACTED POSITION - Google Patents

Abstract

The invention relates to a method of maneuvering an aircraft undercarriage between an extended position and a retracted position, the undercarriage having a leg (2) articulated on a structure of the aircraft to be movable between the two positions. being stabilized in the deployed position by means of a bracing member (10) having two members (11,12) hinged together, one of which is coupled to the leg and the other coupled to the structure of the aircraft, and brought into aligned position when the leg is in the deployed position. According to the invention, the aircraft is equipped with a rotary actuator (20) comprising first and second cranks (22, 24) which are freely rotatable about a same axis of rotation but whose relative angular position is controllable and which are arranged to stabilize the members of the bracing member in substantially aligned position.

Description

The invention relates to a method for maneuvering an aircraft undercarriage between a deployed position and a retracted position.

BACKGROUND OF THE INVENTION

Aircraft undercarriages are known comprising a leg mounted articulated on a structure of the aircraft to be movable between a deployed position and a retracted position. The leg is stabilized in the deployed position by means of a bracing member often comprising two members hinged together, one of the members being harnessed to the leg and the other coupled to the structure of the aircraft, the two members being maintained in a substantially aligned position by a stabilizing member forming a lock which can be unlocked to allow the leg to be raised from the deployed position to the retracted position. To do this, such undercarriages generally comprise an unlocking actuator for unlocking the stabilization member and breaking the alignment of the bracing member, and an operating actuator for raising the leg towards the retracted position.

However, it is possible to use only one actuator ensuring the two functions. For example, in document FR2946319, it has been proposed to use a rotary electromechanical type actuator actuated coupled to one of the arms of the strut stabilization member in an aligned position in order to both operate the undercarriage and unlocking the stabilization member.

Maintaining the leg in the retracted position generally requires the use of an attachment box secured to the structure of the aircraft and comprising a hook in which an olive secured to the leg engages when it arrives in position retracted. However, realignment solutions are known in which the two members of the bracing member or the two members of the stabilization member are in the aligned position when the undercarriage is in the retracted position, which allows the housing to be removed. hanging.

OBJECT OF THE INVENTION

The invention aims to propose a method of operating an aircraft undercarriage between a deployed position and a retracted position using only one actuator.

PRESENTATION OF THE INVENTION

In order to achieve this goal, a method of operating an aircraft undercarriage between a deployed position and a retracted position is proposed, the undercarriage comprising a leg mounted articulated on a structure of the aircraft to be movable between the deployed position and the retracted position, being stabilized in the deployed position by means of a bracing member comprising two members articulated together, one of the members being harnessed to the leg and the other harnessed to the structure of the aircraft. According to the invention, there is arranged on the aircraft a rotary actuator comprising first and second cranks mounted freely rotating about the same axis of rotation but whose relative angular position is controllable, the first crank being connected to the member bracing by a first connecting rod while the second crank is connected to the leg by a second connecting rod, so that the cranks have:

- A first relative angular position in which the first crank and the first connecting rod are brought into a first alignment when the leg is in the deployed position and thus stabilize the members of the bracing member in the substantially aligned position;

- A second relative angular position in which the second crank and the second connecting rod are brought into a second alignment when the leg is in the retracted position and thus stabilize the leg in the retracted position.

Such an arrangement unequivocally links the relative angular position of the leg with respect to the structure of the aircraft and the relative angular position of the two cranks. According to the invention, it is made so that the deployed position of the leg corresponds to a first alignment of the first crank and the first connecting rod, while the retracted position corresponds to a second alignment of the second crank and the second connecting rod . The first alignment makes it possible to stabilize the bracing member in the aligned position, and therefore the leg in the deployed position, while the second alignment stabilizes the leg in the retracted position, which eliminates any recourse to a hooking box.

By alignment of a crank and its associated connecting rod, it is understood here that the two elements are in a position such that their axis of articulation, the axis of coupling of the connecting rod on the undercarriage and the axis of rotation of the crank are contained substantially in the same plane. However, and as is well known, by slightly protruding to bring the two elements in slightly misaligned (overcentered in by stops between said elements, stop are maintained by the no aligned alignment stabilization can be obtained the position perfectly a very English position) defined These positions in residual torque of the actuator when it is not supplied (c <

electromagnetic due to permanent magnets electromagnetic actuator, or couples the trapping of fluid in the chambers or for due one of

The actuator, for a hydraulic actuator). This arrangement therefore makes it possible to avoid any recourse to an auxiliary locking member, the alignment of each connecting rod / crank pair taking place.

DESCRIPTION OF THE FIGURES

The invention will be better understood in the light of the following description of a particular embodiment of the invention, with reference to the figures of the appended drawings, among which:

- Figures 1 and 2 are perspective views of a landing gear fitted according to the invention with an actuator with two cranks, shown in the deployed position and in the retracted position respectively;

Figures 3 to 6 are side views of the undercarriage of Figure 1, respectively in the deployed position, at the start of the lift, during lift, and in the retracted position;

- Figure 7 is a detail perspective view showing the alignment between a crank and the associated connecting rod;

- Figure 8 is a sectional view of an elastic stop mounted on the ceiling of the hold to cooperate with the strut when the undercarriage is in the retracted position;

- Figure 9 is a side view of the undercarriage in the retracted position, the strut coming to bear against the elastic stop.

DETAILED DESCRIPTION OF THE INVENTION

With reference to FIGS. 1 and 2, the invention applies here to a landing gear 1 comprising a leg 2 carrying wheels 3 in the lower part and articulated on a structure of an aircraft along a substantially horizontal articulation axis XI in service . The leg is movable between a deployed position illustrated here and a retracted position visible in FIG. 2. The leg 2 is stabilized in the deployed position by means of a bracing member 10 comprising two members hinged together, in this case a panel 11 articulated on the structure of the aircraft along an axis of articulation X2 and an arm 12 articulated on the leg 2 and on the panel 11 along respective axes of articulation X3 and X4. In the deployed position, the arm 12 and the panel 11 are in a substantially aligned position.

According to the invention, there is provided a rotary actuator 20 mounted for free rotation on the structure of the aircraft along an axis of rotation X5 parallel to the axes of articulation XI to X4. The rotary actuator comprises a casing 21 provided with an appendage forming a first crank 22, and comprises a shaft 23 mounted rotating according to the axis of rotation X5 and carrying a second crank 24. The relative angular position between the two cranks 22, 24 can be modified by feeding the actuator to rotate the shaft 23 relative to the casing 21, and can be fixed and maintained thanks to the residual torque of the actuator 20 when it is not supplied. The first crank 22 is here coupled to the panel 11 of the bracing member 10 by means of a first connecting rod 25 (here a double connecting rod extending on either side of the end of the panel 11) articulated on the first crank 22 along a hinge axis X6 and articulated on the panel 11 along a hinge axis X7, while the second crank is coupled to the leg 2, more precisely on a horn 26 thereof, by means of 'a second connecting rod 27 articulated on the second crank 24 along an axis of articulation X8 and articulated on the horn 26 according to a

hinge pin X9. Here, all the axes XI to X9 are parallel to each other. A such provision dregs of way univocal the position relative angular of the cranks 22.24 and the position angular of the leg 2 with regard to the structure of the aircraft. In the position shown at the figure 3 , in which the leg 2 East in position

deployed, the relative angular position of the cranks is such that the first crank 22 and the first connecting rod 25 are in a substantially aligned position, called the first alignment. More precisely, the first alignment is a position obtained by passing the first crank 22 and the first connecting rod 25 slightly beyond their geometric alignment (which is defined by the perfect alignment of the axes X5, X6, X7 in a same plan) to bring them on respective stops. As visible in FIG. 7, the stop is in the form of fingers extending at the end of the first crank and coming to bear against obstacles secured to the first connecting rod 25 which extend opposite the fingers a stop defining the first alignment.

Likewise, the second connecting rod 27 comprises a finger which bears against an obstacle 37 secured to the second in FIG. 7, the second crank 25 and the second connecting rod are in the position of second alignment, in which the finger 36 is in contact against obstacle 37.

Returning to FIG. 3, it will be noted that the first crank 22 cannot rotate, since, the actuator 20 not being supplied, its residual torque prevents the casing 21 and the shaft 23 from rotating relatively to one another. other, and therefore secures them in rotation. Now the shaft 23 is blocked by the second crank 24, itself blocked in rotation by its coupling to the leg 2 via the second connecting rod 27, which is not aligned with the second crank 24.

To raise the leg 2 towards the retracted position, the actuator 20 is supplied to rotate the shaft 23, and therefore modify the relative angular position of the cranks 22, 24. As illustrated in FIG. 4, this rotation has the first effect of breaking the alignment of the first crank 22 and the first connecting rod 24, and therefore of breaking the alignment of the panel 11 and of the arm 12 of the bracing member 10 The undercarriage 2 is therefore no longer stabilized in the deployed position and the leg can be raised to the retracted position. The actuator 20 continuing to be supplied, the leg 2 continues to rise and arrives in an intermediate position illustrated in FIG. 5 in which the first connecting rod 25 pulls on the panel 11 while the second connecting rod 27 pushes on the leg 2, this which has the effect of raising it to the retracted position illustrated in FIG. 6, in which the cranks are in a relative angular position such that the second crank and the second connecting rod 27 arrive in a substantially aligned position, called the second alignment .

In the same way as for the first alignment, the second alignment is in fact a position obtained by passing the second crank 24 and the second connecting rod 27 slightly beyond the geometric alignment (defined by the perfect alignment of the axes X5 , X8, X9 in the same plane) to bring them on respective stops. This alignment blocks the leg 2 in the retracted position, so that this position is stable and does not require the use of an attachment box.

According to a particular aspect of the invention, the doors 30 hinged to the undercarriage are hinged to the structure of the aircraft along axes X10 and which close the hold in which the undercarriage is housed in the retracted position by links 31 directly harnessed to horns 32 projecting from the panel 11 of the bracing member 10. To facilitate understanding of the invention, the pants flap is not shown which is harnessed to the leg and which closes the hold in addition to the two doors 30 when the undercarriage is in the retracted position, and which remains open when the undercarriage is in the deployed position. In the two positions of the undercarriage illustrated in FIGS. 1, 2, 3, 6, it is noted that the doors 30 are in the closed position while they open during the maneuver of the undercarriage, as can be seen on the figures

4.5. Maintaining the doors in the closed position requires installing a preload in the doors 30 to be certain that they will not yawn in flight under the effect of aerodynamic forces. To this end, the length of the links 31 is adjusted so that in each of the retracted or deployed positions of the undercarriage, the doors 30 come to bear on a stop 35 (visible in FIG. 1) secured to the structure of the aircraft a little before the connecting rod / crank assembly in alignment, and in particular, a little before passing through the preceding geometric alignment position. The arrival of the doors 30 against the stop 35 then requires pulling on the rods to prestress the doors 30, which then act as return springs confirming the rod / crank assembly on its internal stop, and therefore confirming the alignment of that -this.

To supplement the prestressing induced by the closing of the doors, or to replace the latter if the doors are not coupled to the undercarriage, it is possible to use another external source of prestressing, such as for example an elastic stop 50 illustrated in Figure 8. The elastic stop comprises a base 51 intended to be fixed to the ceiling of the hold. The base 51 carries a hollow body 52 provided with a terminal opening carrying a guide 53. A piston 54 is slidably mounted in the guide 53 to project from the body 52. The piston 54 is pushed towards a projecting position visible in FIG. 8 by Belleville elastic washers 55 positioned inside the hollow body 52 which exert a prestress on the piston 54. To make the piston 54 retract, an effort should be exerted on the latter at least equal to the prestress installed by Belleville 55 washers.

As can be seen in FIG. 9, the elastic stop 50 is positioned on the ceiling of the hold of the undercarriage so that a portion of the bracing member, in this case here the strut panel 11, comes in abutment against the piston 54 when the undercarriage reaches the retracted position, before the second crank 24 and the second connecting rod 27 arrive in the geometrical alignment preceding the so-called second alignment position. Thus, to pass the geometrical alignment and go beyond it to reach the second alignment, the strut panel 11 must push the piston 54 against the prestress installed by the Belleville washers 55. In this way, the prestress of the Belleville washers are transmitted to the strut panel 11, in the same way that the pretensioning of the doors was transmitted to the strut panel via the horns 32.

Of course, the prestressing of the doors and / or of the elastic stop can be transmitted to another location of the undercarriage than the strut panel, for example directly to the undercarriage housing. The prestressing can also be exerted by one or more internal springs which confirm the second crank 24 and the second connecting rod 27 in their second alignment.

The invention is not limited to what has just been described, but on the contrary covers any variant coming within the scope defined by the claims.

In particular, although here all the articulation axes are parallel to each other, the invention naturally applies to kinematics with non-parallel axes, as long as each rod / crank assembly of the actuator comes into alignment when the leg is in one of the extended or retracted positions.

Claims (6)

1. Method for maneuvering an aircraft undercarriage between a deployed position and a retracted position, the undercarriage comprising a leg (2) mounted articulated on a structure of the aircraft to be movable between the deployed position and the retracted position , by being stabilized in the deployed position by means of a bracing member (10) comprising two members (11,12) articulated together, one of which is harnessed to the leg and the other harnessed to the structure of the aircraft , and brought into the aligned position when the leg is in the deployed position, characterized in that a rotary actuator (20) is arranged on the aircraft comprising first and second cranks (22,24) mounted freely rotating around a same axis of rotation but whose relative angular position is controllable, the first crank (22) being connected to the bracing member by a first connecting rod (25) while the second crank (24) is connected to the leg by a second connecting rod (27), so that the cranks have: a first relative angular position in which the first crank (22) and the first connecting rod (25) are brought into a first alignment when the leg is in the deployed position and thus stabilize the members of the bracing member in the substantially aligned position; a second relative angular position in which the second crank (24) and the second connecting rod (27) are brought into a second alignment when the leg is in the retracted position and thus stabilize the leg in the retracted position. 2. Method according to claim 1, wherein the first alignment and the second alignment are defined by stops between the crank and the associated connecting rod. 3. Method according to claim 1, in which one of the doors (30) the undercarriage is housed in the deployed closed position and in splint to the bracing member closing the hold in which position when position 4. Method according to the retracted, The undercarriage retracted. doors is in claim position 3, in installs a prestress in the they are in the closed position, prestress confirms the alignment rod / crank concerned. doors sort of 5. Method according to claim 1, place (50) on the structure of the aircraft one so that one come The undercarriage a prestress confirming the alignment of the second connecting rod and the second crank when the undercarriage is. in the retracted position. 6. The method of claim 5, wherein the 20 stop comprises a piston (54) held projecting from a body (52) by the action of Belleville washers (55) installing a preload on the piston (54), and on which a portion (11) of the member of bracing comes to bear when the undercarriage is in position 25 retracted.