Landing gear of an aircraft with compact steering device

(54) Title: TRAIN STEERING DEVICE (57) Summary: steering device for train

OF AIRCRAFT LANDING (30) Unionist Priority: 28/06/2005 fr 0551798 (73) Owner (s): airbus france (72) Inventor (s): paul de ruffray, rodolphe morel (74) Attorney (s): Custodian De Almeida & Cia (86) International Order: pct ep2006063480 of 06/22/2006 (87) International Publication: wo 2007/000411 of 04/01/2007

AIRCRAFT LANDING. The object of the invention is a steering device for aircraft landing gear (1) characterized in that it comprises at least one means of maneuver in rotation (2, 3, 4, 5) of the wheels (6) of the landing gear arranged along the leg (13) of the landing gear.

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STEERING DEVICE FOR AIRCRAFT LANDING TRAIN

The present invention relates to a space-saving steering device for aircraft landing gear.

Steering devices for aircraft landing gear traditionally include shock absorbers arranged perpendicular to a landing gear leg, acting on the orientation of the front landing gear leg.

These dampers are fixed on the trunk receiving this train leg by an arm and are joined by ball joints to a solidary ring by means of a compass on the rotating lower part of the train leg in order to command the rotation of the train leg. An example of a previous embodiment is given in figure 1.

In addition to the compass, in these previous devices, at least one connecting element, the shock absorbers according to the example, is arranged perpendicularly to the train leg and extends beyond the train leg. This element requires a large space in the case of the train for its accommodation.

The present invention proposes to reduce the volume occupied by the mobile steering device of an aircraft landing gear, particularly the front landing gear, in order to reduce the dimensions of the train compartment in which this landing gear is housed.

To this end, the present invention relates to an aircraft landing gear steering device comprising at least one means of maneuver in rotation of the landing gear wheels arranged along the landing gear leg.

Advantageously, the means of operation arranged along the landing gear leg comprises at least one damper and one rack, the damper activating the rack.

More particularly, the rack drives in rotation, through pinions with angled transmission, a rotating crown in rotation of a slider carrying the wheels of the landing gear.

According to a particular embodiment of the invention, the rotating crown is coaxial with the leg of the landing gear and drives the rotating wheels through a rotating ring connected to a compass directing said wheels.

Thus, the steering device arranged along the leg of the landing gear does not extend in a direction perpendicular to the leg and does not impose an increase in the train compartment in a vertical and / or transversal direction for its accommodation when the train is in the retracted position.

Other features and advantages of the invention will be evident from reading the following description of an example of a non-limiting embodiment of the invention with reference to the drawings they represent:

In figures IA and 1B: perspective views of landing gear equipped with steering devices of the prior art;

In figures 2A and 2B: perspective views of a landing gear equipped with the device according to the invention in a straight position and in a change of direction respectively;

In figure 3: a detail of the device according to the perspective invention;

In figure 4: a schematic view of a device with dampers and rack according to a particular embodiment of the invention;

In figure 5: a sectional view of a pinion system of figures 2A and 2B.

Figure IA represents an aircraft's front landing gear with a prior art steering device.

According to this example, the prior art device comprises two dampers A and B arranged perpendicular to the axis of the landing gear leg 13 and forming an angle between them.

In the case of an aircraft of large mass and able to rotate within a small radius of braking, the dampers are long in length to offer sufficient operating stroke.

When the landing gear (or landing gear) enters its compartment, called the train compartment, the shock absorbers exceed the volume occupied by the landing gear upwards, which increases its volume and therefore its mass, and imposes a height important to this compartment which decreases the space available above this compartment.

The example of figure 1B is a landing gear equipped with a telescopic support strut C and comprising shock absorbers Al, A2, Bl, B2, extending laterally the train leg consisting of a trunk 22a and a slide 22b.

In the latter case, a large lateral volume is occupied by these dampers.

In order to reduce the dimensions and mass of the landing gear compartment, it is necessary to decrease the volume occupied by the landing gear, which is offered by the present invention by limiting the volume occupied by the parts extending beyond the train leg.

For example, the landing gear 1 according to the invention of figures 2A and 2B comprises two rotating means 2 for rotating the wheels 6 of the landing gear, arranged along the leg 13 of the landing gear.

On the upper fixed part 22a, called the trunk, reinforcement triangles 20, 21 are fixed, on the opposite ends of them are the axes of rotation of the train, allowing the train to enter and exit its compartment.

The reinforcement triangles 20, 21 and the trunk 22a can be made in one piece, the triangles 20, 21 can thus be separate elements.

The upper fixed part forms an upper tube 7 in whose extension, facing downwards, is the movable part or slide 22b, bearing the wheels 6 and mounted on a shock absorber so that it can slide and rotate in the tube 7 of the trunk 22a.

The rotation of the wheels is carried out as in the prior art by means of a compass 12 set in rotation by a pivoting ring II by rotating the slide 22b on the trunk 22a.

The maneuvering means, arranged along the landing gear leg, comprise here two pairs of dampers 2, but a single damper can also be targeted.

According to the detail of figure 4, each shock absorber 2 consists of simple shock absorbers 3,4, in opposition fed by a double hydraulic circuit 23, 24, and working in opposition. The dampers are arranged along the upper tube 7 and parallel to this tube to exceed, as little as possible, the space occupied by the train leg.

Between the opposing dampers 3, 4, there is a rack 5, the dampers driving the rack. The damper (s) 2, 3, 4 and the rack 5 are attached to the upper tube 7 of the landing gear leg.

An achievement with a single shock absorber with double effect triggering a rack exiting the shock absorber can be targeted accordingly

I with the invention for a low-mass aircraft for which the wheel rotation efforts remain moderate.

To rotate the wheels, the rack 5 drives, in rotation, a rotating crown 8 for driving the wheels 6 of the landing gear shown in figure 3.

The crown is coaxial with the foot 13 of the landing gear and is driven by the rack through pinions with angled transmission 9, 10.

Pinions with angled transmission 9, 10 are tapered pinions, pinion 9 rotating around an axis perpendicular to the axis of the leg and pinion 10 rotating around the axis of the leg.

According to the invention, the rotating crown 8 is made coaxially with the rotating ring 11 connected to a compass similar to that of the prior art, so that the rack arranged parallel to the leg can drive the wheels 6 of the landing gear through the rotating ring 11 connected to bar 12 which controls the rotation of the slide 22b.

Pinion 9, pinion 10 and rotating ring 11 can be assembled elements or can be machined into a single piece.

As previously seen, pinions with angled transmission

9, 10 comprise a first tapered pinion 9, with an axis 15 perpendicular to the 20 axis of the landing gear leg, interlocking over a second tapered pinion 10 coaxial with the crown 8. The first tapered pinion 9 is made in one piece comprising a straight pinion 14, rack 5 engaging over straight pinion 14 coaxial to the first tapered pinion 9.

The damper 2 has two opposing dampers 3, 4 and the rack 5 is made on a central rod common between the pistons 16, 17 of the two opposing dampers 3,4, arranged on top of each other.

Thus, when the hydraulic fluid drives the piston 16 of the upper shock absorber 3, the rack goes down, rotating the first tapered pinion 9 around the axis 15, which turns the crown 8 and the ring 11 in a first direction while , when the hydraulic fluid fills the cavity under piston 17 of the lower shock absorber 4, the rack rises again and turns the crown 8 in the opposite direction.

To avoid any flexion of the central rod carrying the rack, this rod rests on at least one guide follower 18, 19, disposed on the side of the rack opposite the straight pinion 14.

The invention is not limited to the examples shown and notably a single means of operation, such as a rotary electric motor with a vertical tapered output pinion interlocking directly over the second tapered pinion in support of the crown, arranged along leg 13 of the landing gear 1, can replace rack and first taper pinion damper assembly.

The invention applies, on the other hand, to a landing gear leg provided or not with a telescopic support strut.