Linkage mechanism for driving aircraft landing gear bay door

A linkage mechanism for controlling an aircraft landing gear hatch door includes a primary torsion tube having a first portion located inside a landing gear hatch and a second portion outside the landing gear hatch. A first drive apparatus transfer the driving force of a landing gear support column to the primary torsion tube. A secondary torsion tube has an inner end portion located inside the hatch and an outer end portion located outside the hatch. A second drive apparatus is located outside the landing gear hatch and connects the primary torsion tube and the secondary torsion tube outside the hatch. Two third drive apparatuses are connected between the inner end portion of the secondary torsion tube and one of the hatch doors.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to International Application Serial No. PCT/CN2014/084769, filed Aug. 20, 2014, which claims priority to Chinese Application No. 201310513351.8, filed Oct. 25, 2013. International Application Serial No. PCT/CN2014/1084769 is hereby incorporated herein in its entirety for all purposes by this reference.

FIELD OF THE DISCLOSURE

The present invention relates to a linkage mechanism for driving an aircraft landing gear bay door so as to obtain the linkage between bay doors and an aircraft landing gear, and belongs to the field of landing gear structure design.

BACKGROUND OF THE DISCLOSURE

Generally, the aircraft landing gear bay doors of an aircraft have two kinds of structures: an independent structure and a linkage structure. The independent structure is designed in such a way that the bay doors of the landing gear are separately controlled to open and close independent of the retraction and release of the landing gear. The bay doors are opened before the retraction and release of the landing gear, and are closed after the retraction and release of the landing gear. The linkage structure is designed in such a way that a driving point is set on a retraction and release member of the landing gear such as a landing gear strut or a drag strut, and the bay doors are forced to open and close through a linkage mechanism by virtue of the movement of the retraction and release member of the landing gear, thereby obtaining a function of opening the bay door before the retraction and release of the landing gear and closing the bay door after the retraction and release of the landing gear. However, whatever the structures of the bay doors, they are arranged in a landing gear bay and have a symmetric configuration. In order to avoid the interference during the retraction and release of the landing gear, the landing gear bay must have enough space to arrange the linkage mechanism for driving the bay doors.

WO 2010/063110A1 discloses a driving device for a bay door of a landing gear with a linkage between the landing gear and the bay door. The driving device is arranged in a bay of the landing gear and has a symmetric configuration. However, in this patent, two bay doors of the bay of the landing gear are driven separately by two symmetric structures on two sides, that is, the two bay doors are respectively equipped with a driving mechanism which needs to be installed and adjusted, thereby causing a nonsynchronous movement between two driving mechanisms.

Patent application CN 102470920 A discloses a device for driving a bay door of an aircraft landing gear with a linkage between the door and the aircraft landing gear. The device is also arranged in the aircraft landing gear bay and has a symmetric configuration. In this driving device, a driven landing gear strut forces a panel of a breaker strut to pivot, thereby causing a generator lever20′ linked with the panel to pivot. This movement of the generator lever20′ is transmitted to a rocker lever23′ by a transferring rod24′, thus causing the rocker lever to pivot in a direction that tends to push against left and right links25a′ and25b′ symmetrically arranged and associated with the left and right bay doors, and thus open the doors. However, the movement needs to be transmitted from the landing gear strut to the transferring rod and to the rocker lever via an intermediate part such as the breaker strut, thus, on one hand, this device takes a relatively large space in the bay of the aircraft landing gear; on the other hand, the force cannot be transmitted directly, thereby affecting the force transferring performance.

BRIEF SUMMARY

The present invention provides a linkage mechanism used for driving an aircraft landing gear bay door, which can save the space in the landing gear bay and obtain a good force transferring performance.

For this purpose, according to one aspect of the present invention, the present invention provides a linkage mechanism used for driving an aircraft landing gear bay door, the linkage mechanism being suitable for connecting with bay doors and a landing gear and converting the back-and-forth movement of the landing gear between a retracted position inside of the landing gear bay and a released position outside of the landing gear bay, respectively into the back-and-forth movement of the bay doors between a closed position and an open position, the linkage mechanism comprising:

a primary torsion tube comprising a first portion located inside a landing gear bay and a second portion outside the landing gear bay;

a first drive apparatus connected between the first portion and a landing gear strut so as to transfer the driving force of the strut to the primary torsion tube;

a secondary torsion tube comprising an inner end portion located inside the bay and an outer end portion outside the bay;

a secondary drive apparatus connected between the outer end portion and the second portion for transmitting a torque of the primary torsion tube to the secondary torsion tube; and

two third drive apparatuses respectively connected between the inner end portion of the secondary torsion tube and one of the bay doors so as to enable the bay doors to be driven by the secondary torsion tube for accomplishing the opening and closing movement.

According to this aspect of the present invention, the force transferring structure from the primary torsion tube to the secondary torsion tube is positioned outside of the landing gear bay, so the arrangement space in the landing gear bay can be saved to the utmost extent; the interference risk between the motion mechanisms can be reduced; the driving force of the landing gear strut is directly transmitted to the primary torsion tube via a first rod and a primary inner crank without being transmitted through the breaker strut as in the prior art, so the force transferring performance is good; and the torque is transmitted via one side, i.e., the torque is transmitted via one secondary torsion tube to control two bay doors simultaneously, so the quantity of parts is reduced, the space is saved, and the motion synchronism of the doors is high.

The first drive apparatus comprises a primary inner crank and a first rod, one end of the primary inner crank is securely connected to the first portion of the primary torsion tube, and two ends of the first rod are pivotally connected between the other end of the primary inner crank and the strut.

Preferably, the first rod is a L-shaped rod. The L-shaped rod may better prevent the linkage mechanism from interfering with the landing gear strut during the moving process.

Preferably, the L-shaped rod comprises a body portion and a moving portion removably connected with each other. The L-shaped rod has a segmented design, and the length of the rod may be adjusted depending on the position of the whole machine.

Preferably, the body portion has a sliding hole and a first rack structure, and the moving portion has a screw hole and a second rack structure. The sliding hole is configured in such a way that a screw passing through the screw hole may slide along the sliding hole so as to adjust a connecting position of the body portion and the moving portion. In the connecting position, the first rack structure is engaged with the second rack structure, and the body portion and the moving portion are securely connected by the screw passing through the screw hole and the sliding hole. This configuration can change the connecting position by changing the engaging position of the rack structures so as to change the length of the rod, thereby further adjusting the position of the whole machine.

Preferably, the primary inner crank and the first portion of the primary torsion tube are connected with each other through the bolt by virtue of their respective lug structures. This flange type connecting structure enables the bolt to only suffer a shear force, thus each bolt bears a balanced force, so as to obtain a high strength and a good force transmission performance.

Preferably, the secondary drive apparatus comprises: a primary outer crank having one end securely connected to the second portion of the primary torsion tube; a secondary outer crank having one end securely connected to the outer end portion of the secondary torsion tube; and an intermediate rod having two ends pivotally connected between the other end of the primary outer crank and the other end of the secondary outer crank.

Preferably, each third drive apparatus comprises: a secondary inner crank having one end securely connected to the inner end portion of the secondary torsion tube; and a door rod having two ends pivotally connected between the other end of the secondary inner crank and one of the bay doors.

More preferably, the secondary inner crank and the inner end portion of the secondary torsion tube are connected with each other through the screw by virtue of their respective lug structures.

Preferably, the inner end portion of the secondary torsion tube are supported on two side walls of the landing gear bay by a ball bearing device, and the first portion and the second portion of the primary torsion tube are respectively supported on one side wall of the landing gear bay and an aircraft supporting structure outside of the side wall by a ball bearing device. Since the two ends of each torsion tube are fixed, this fixing form with two ends simply supported can better provide a supporting function to the torsion tubes and ensure a stable rotation of the torsion tubes.

REFERENCE SIGNS

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

The following description will describe the implementing and the applying of the detailed embodiments of the present invention. However, it should be appreciated that the described embodiments are only used to illustrate the special form for implementing and applying the present invention in an exemplary manner, rather than limit the scope of the present invention.

In the following description, the attached drawings are referred to. The drawings constitute a part of the present invention, and some specific embodiments for implementing the present invention are shown by way of example in the drawings. In this regard, some orientation terms, such as “left”, “right”, “top”, “bottom”, “front”, “back”, “guide”, “forwards”, and “backwards”, are used with reference to the directions shown in the drawings. Thus, the members of the embodiments of the present invention may be arranged in different directions, and the orientation terms are used as example rather than limitation.

FIGS. 2 and 3illustrate a linkage mechanism100for driving an aircraft landing gear according to a preferred embodiment of the present invention. The linkage mechanism100is suitable for connecting with the bay doors and the landing gear and converting the back-and-forth movement of the landing gear between a retracted position inside of the landing gear bay and a released position outside of the landing gear bay, respectively into a back-and-forth movement of the bay doors between a closed position and an open position. The linkage mechanism100comprises a primary torsion tube10comprising a first portion positioned in a landing gear bay and a second portion positioned outside the landing gear bay; a first drive apparatus connected between the first portion and a strut201of the landing gear200in order to transmit the driving force of the strut201to the primary torsion tube10; a secondary torsion tube20comprising an inner end portion positioned in the landing gear bay and an outer end portion positioned outside the landing gear bay; a secondary drive apparatus connected between the outer end portion of the secondary torsion tube20and the second portion of the primary torsion tube10for transmitting a torque of the primary torsion tube10to the secondary torsion tube20; and two third drive apparatuses respectively connected between the inner end portion of the secondary torsion tube and one of bay doors so as to enable the bay doors to be driven by the secondary torsion tube for accomplishing the opening and closing movement.

Stilling referring toFIGS. 2 and 3, in this embodiment, the first drive apparatus preferably comprises a primary inner crank11and a first rod12. One end of the primary inner crank11is securely connected to the first portion of the primary torsion tube10, and the two ends of the first rod12are pivotally connected between the other end of the primary inner crank11and the strut201.

As clearly shown inFIG. 2, the secondary drive apparatus preferably comprises a primary outer crank13, a secondary outer crank21and an intermediate rod30. One end of the primary outer crank13is securely connected to the second portion of the primary torsion tube10; one end of the secondary outer crank21is securely connected to the outer end portion of the secondary torsion tube20; and the two ends of the intermediate rod are pivotally connected between the other end of the primary outer crank13and the other end of the secondary outer crank21.

Still referring toFIGS. 2 and 3, the two third drive apparatuses are a left drive apparatus and a right drive apparatus respectively. The left drive apparatus comprises a left inner crank22and a left door rod24, one end of the left inner crank22is securely connected to the inner end portion of the secondary torsion tube20, and two ends of the left door rod24are pivotally connected between the other end of the left inner crank22and a left door401(not shown). The right drive apparatus comprises a right inner crank23and a right door rod25, one end of the right inner crank23is securely connected to the inner end portion of the secondary torsion tube20, and the two ends of the right door rod25are pivotally connected between the other end of the right inner crank23and a right door402.

As shown inFIGS. 4A, 4B and 4C, in this embodiment, the first rod12is preferably a L-shaped rod and comprises a body portion120and a moving portion121removably connected with each other, that is to say, the first rod12has segmented design. The body portion120is provided with a sliding hole123and a first rack structure124, and the moving portion121is provided with a screw hole125and a second rack structure (not shown). The sliding hole123is configured in such a way that a screw126passing through the screw hole125may slide along the sliding hole123so as to adjust a connecting position of the body portion120and the moving portion121. In the connecting position, the first rack structure124is engaged with the second rack structure, and the body portion120and the moving portion121are securely connected by the screw126passing through the screw hole125and the sliding hole123. This configuration can change the connecting position by changing the engaging position of the two rack structures so as to change the length of the first rod12, thereby further adjusting the position of the whole machine. However, it should be appreciated that the first rod12may also be designed as a straight rod or other rods in case that the space in the landing gear bay is enough.

As shown inFIG. 5, in this embodiment, the primary inner crank11preferably has a crank lug structure113, and the primary torsion tube10preferably has a torsion tube lug structure103, thus the primary inner crank11and the primary torsion tube10are connected through a bolt15by virtue of their respective lug structures. This flange type connecting structure enables the bolt15to only suffer a shear force, thus each bolt15bears a balanced force, so as to obtain a high strength and a good force transmission performance. AlthoughFIG. 5shows the connection structure between the primary inner crank11and the primary torsion tube10, it should be appreciated that the connection structure between the left inner crank22, the right inner crank23and the secondary torsion tube20may also be implemented through the bolt by virtue of their respective lug structures.

In this embodiment, the secondary torsion tube20is preferably supported on two side walls of the landing gear bay by a ball bearing device (not shown) in the interior of the left inner crank22and between the right inner crank23and the secondary outer crank21. Further, the primary torsion tube10is supported on a corresponding side wall403of the landing gear bay by a ball bearing device between the primary inner crank11and the primary outer crank13, and meanwhile, and the second portion of the primary torsion tube10in the landing gear bay is also preferably supported on an aircraft supporting structure300outside of the side wall403by a ball bearing device. Since the two ends of each torsion tube10,20are fixed, this fixing form with two ends simply supported can better provide a supporting function to the torsion tubes10,20and ensure a stable rotation of the torsion tubes10,20.

Returning toFIG. 3, although the outer end portion of the primary torsion tube10is fixed on the aircraft supporting structure300in a tripod form, it should be appreciated that the aircraft supporting structure300for fixing the primary torsion tube10is not limited to this structure, as long as it can support and fix the primary torsion tube10and prevent the primary torsion tube10that passes through the side wall403of the landing gear bay from swinging.

The following description will introduce the operating principle of the linkage mechanism in this embodiment with reference toFIGS. 6-8andFIGS. 2-3.

During the process of the landing gear200moving from a released position (seeFIG. 6) to a retracted position (seeFIG. 8) or from the retracted position to the released position (FIG. 7shows an intermediate position), the strut201of the landing gear200forces the primary inner crank11to rotate via the first rod12, and the primary torsion tube10transmits the torque of the primary inner crank11to the primary outer crank13. Then, the primary outer crank13forces the secondary outer crank21to rotate via the intermediate rod30, and the secondary torsion tube20transmits the torque to the left inner crank22and the right inner crank23simultaneously. Then, the two secondary inner cranks force the left door401and the right door402to move simultaneously via the left door rod24and the right door rod25.

The linkage mechanism in this embodiment further has the following features: the linkage mechanism100is connected by two level cranks, and transmits the aerodynamic load (i.e., aerodynamic drag) of the doors to the landing gear strut using lever principle of the cranks, which effectively reduces the inhibition of the aerodynamic load of the doors to the normal retraction and release and emergency release of the landing gear and obtain a good force transferring performance.

It should be appreciated that the linkage mechanism of the present invention can be widely applied to the airplane, such as a front door of a front landing gear of an airliner, or a door of a center main landing gear of a wide-body airliner.

The above illustrates and describes basic principles, main features and advantages of the present invention. Those skilled in the art should appreciate that the above embodiments do not limit the present invention in any form. Technical solutions obtained by equivalent substitution or equivalent variations all fall within the scope of the present invention.