Pylon including a primary structure formed of at least one longeron and one panel assembled by welding

The pylon, intended to support a flying vehicle engine, includes a primary structure formed by at least one longeron and one panel, the panel including at least one end part provided with a notch, the longeron being provided with an end adapted to be positioned in the notch, the panel and the longeron being assembled by welding a part of the end to a part of the notch. A welded primary structure enables minimization of the blanks of parts associated with the longerons and with the panels by avoiding having recourse to the production of edges.

FIELD OF THE INVENTION

The present invention concerns a pylon intended to support an aircraft engine under an aircraft wing, the pylon including a primary structure formed by at least one longeron and one panel assembled by welding, as well as an aircraft provided with such a pylon.

BACKGROUND OF THE INVENTION

As a general rule, a flying vehicle such as an aircraft, in particular a transport aircraft, is propelled by engines. Here is meant by engine any type of propulsion means such as a turboprop, a turbojet, etc. Each engine may be attached by a pylon under a wing, also known as an airfoil, to the fuselage of an aircraft or to other elements such as the tail unit.

A pylon usually supports the engine and transmits the forces generated by the operation of the engine to the airfoil of the aircraft. It also enables the transmission of fuel, electricity, hydraulics and air between the engine and the aircraft.

To fulfill its functions the pylon includes a rigid primary structure preferably made of titanium. This primary structure is formed of a plurality of ribs arranged successively in a longitudinal direction and constituting the framework of a “box section” type compartment. The ribs connect an upper longeron and a lower longeron while panels arranged laterally complete the box section. Each longeron is generally fixed by its edges to the side panels by means of bolt type fixing means.

The manufacture of a primary structure usually entails the production of blanks of the parts that respectively correspond to the side panels and to the upper and lower longerons. Each blank is machined in order to obtain the side panels and the longerons forming the primary structure. After machining the edges of each lateral panel and of each longeron are pierced throughout their length and then brought into contact in order to be fixed together by the bolts.

The production of a primary structure box section requires a large quantity of raw material including a proportion of material waste, which can generate high production costs, in particular due to the necessity to produce the edges.

Such a solution is therefore not completely satisfactory.

The documents US2014/151497 and EP3476740 disclose such pylons in which side panels are assembled to form the pylon.

BRIEF SUMMARY OF THE INVENTION

Aspects of the present invention may remedy this disadvantage. An aspect concerns a pylon intended to support an engine of a flying vehicle, in particular an aircraft, and including a primary structure formed by at least one longeron and one panel.

According to an embodiment of the invention, said panel includes at least one end part in which a notch is formed, said longeron being provided with at least one end adapted to be positioned in said notch, said panel and said longeron being assembled by welding at least a part of said end to at least a part of said notch.

According to an aspect of the invention, the primary structure is therefore produced by welding its components, which minimizes the blanks of the parts associated with the longerons and with the panels by avoiding recourse to the production of edges. Moreover, welding of the end of the longeron in the notch of the end part of the panel renders the assembly more robust and simpler to produce.

Said notch is advantageously formed of an abutment, said end of the longeron including a contact face, at least a part of said abutment being conformed to said contact face.

In accordance with a first embodiment, said notch also includes a lip formed in a plane parallel to said longeron, said lip forming with the abutment an angle substantially equal to 90 degrees.

In accordance with a second embodiment, said notch also includes a lip formed in a plane parallel to said longeron, said lip forming an angle greater than 90 degrees with the abutment.

Moreover, in accordance with a first embodiment, said end also includes a surface part of said longeron, said surface part being in contact with said lip of the notch.

Moreover, in a second embodiment, said end also includes a surface part of said longeron, said surface part and said lip of the notch being spaced apart from one another.

In accordance with a first particular embodiment the weld is produced at a surface joining at least a part of said abutment with said contact face.

In a second particular embodiment, the weld is produced on a surface joining the abutment with the contact face and on a part of the surface where said lip of the notch joins the surface part of said longeron.

In accordance with a first embodiment, the weld is produced in a continuous manner along said end of the longeron.

In accordance with a second embodiment, the weld is produced in a discontinuous manner along said end of the longeron.

The pylon advantageously includes a primary structure formed of a plurality of pairs of panels and longerons, each of the pairs including a panel and a longeron and the longeron and the panel of each of said pairs are assembled by welding as described hereinabove.

The present invention also concerns a method of welding a panel and a longeron forming part of the pylon as described hereinabove.

In accordance with an aspect of the invention said method includes the following steps:a step of producing the notch in the end part of said panel;a step of positioning said end of said longeron in said notch in said panel; anda step of welding a part of said end of said longeron to at least a part of said notch.

The present invention moreover concerns a flying vehicle, in particular an aircraft, that is provided with a pylon as described hereinabove.

DETAILED DESCRIPTION

A flying vehicle engine propels the latter. It is generally connected to the rest of the structure of the flying vehicle by a pylon1as represented inFIG.2. In the context of the invention a flying vehicle may be an aircraft, a flying wing, an airplane with no fuselage, etc.

In a preferred application described hereinafter with reference toFIG.1the flying vehicle is an aircraft AC, in particular a transport aircraft. That aircraft AC includes a fuselage2to which two wings3G,3D are fixed on respective opposite sides. These wings3G and3D are also referred to as airfoils3G,3D. The aircraft AC also includes engines4G,5G, and4D,5D for propelling it in a forward direction S. The pylon1for illustrating the invention and represented inFIGS.1and2is adapted to support each of the engines4G,5G,4D,5D under the wings3G and3D.

To facilitate the following description three mutually orthogonal directions are introduced. A direction X corresponds to the longitudinal direction of the pylon1and is parallel to the longitudinal direction of the fuselage2of the aircraft AC oriented in the forward direction S of the aircraft AC. Moreover, a transverse direction Y corresponds to the direction oriented transversely relative to the pylon1. The transverse direction Y also corresponds to the general direction in which the wings3G and3D of the aircraft AC extend. Finally, a vertical direction Z corresponds to the vertical direction of the pylon1and is parallel to the direction representing the height.

Moreover, the adjectives “front” and “rear” are defined relative to the longitudinal direction X, respectively in the forward direction S of the aircraft AC when the engines are exerting a thrust and in the direction opposite to the forward direction S. Moreover, the adjectives “upper” and “lower” are defined relative to the vertical direction Z respectively toward the wing3G,3D and toward the engines4G,5G,4D,5D. Finally, the adjectives “external” and “internal” are defined relative to the transverse direction Y, respectively toward the tip of the wings3G,3D and toward the fuselage2.

As represented inFIG.2, the pylon1includes a primary structure6in the form of a box section that extends along the longitudinal direction X. The primary structure6is formed of an upper longeron7. That upper longeron7includes an front upper longeron7A and an rear upper longeron7B each of which is of substantially elongate shape in the longitudinal direction X. The front upper longeron7A and the rear upper longeron7B are arranged successively in the longitudinal direction X and are fixed together in the transverse direction Y by fixing means (not represented). For example, those fixing means are welds. The front upper longeron7A and the rear upper longeron7B extend in planes substantially perpendicular to the vertical direction Z. The planes in which the front upper longeron7A and the rear upper longeron7B extend have a non-zero angle between them.

The primary structure6also includes a lower longeron8of substantially elongate shape in the longitudinal direction X. The upper longeron7and the lower longeron8are connected by two side panels extending in planes that may be substantially perpendicular to the transverse direction Y. Those side panels include an internal lateral panel9A (hereinafter “internal panel9A”) and an external lateral panel9B (hereinafter “external panel9B”). In a preferred embodiment the internal panel9A and the external panel9B are arranged in planes inclined to one another.

As represented inFIG.2, each of the side panels is provided with end parts10extending substantially along the longitudinal direction X. The end parts10include an upper part10A and a lower part10B arranged opposite one another in the vertical direction Z.

In a preferred embodiment a notch17is formed in the upper part10A of the internal panel9A and the external panel9B so as to be arranged facing the upper longeron7. A notch17is also formed in the lower part10B of the internal panel9A and the external panel9B so as to be placed facing the front upper longeron7A and the rear upper longeron7B. Each notch17formed in a lower part10B extends in the direction in which the lower longeron8extends. Each notch17formed in an upper part10A extends in the direction in which the front upper longeron7A and the rear upper longeron7B extend.

As represented inFIGS.3,4A and4B, each notch17formed in the upper part10A is formed of an abutment12. The abutments12of the upper edges10A of the internal panel9A and of the external panel9B face one another. In a similar manner, each notch17formed in the lower part10B of each of the internal panel9A and the external panel9B includes an abutment12(not represented) against which the lower longeron8is arranged.

Moreover, the abutment12of the notch17in the upper part10A is configured to be in contact with the upper longeron7. The abutment12of the lower part10B is adapted to be in contact with the lower longeron8. The abutments12are adapted to block any movement of the upper longeron7and the lower longeron8in the transverse direction Y and to be in contact to form a weld line and to close the primary structure6.

As represented inFIGS.3,4A and4B, the notch17also includes a lip11. In the context of the invention there is meant by lip11a surface forming with the abutment the notch17. The lip11of the notch17formed in the upper part10A extends in a direction parallel to the direction in which the upper longeron7extends. The lip11of the notch17formed in the lower part10B extends in a direction parallel to the direction in which the lower longeron8extends. In a first embodiment the lip11and the abutment12are arranged in planes at an angle substantially equal to 90 degrees. In a second embodiment (not represented) the lip11and the abutment12form an angle greater than 90 degrees. The abutment12then extends in a plane parallel to the plane in which the internal panel9A or the external panel9B extends.

Moreover, the upper longeron7is provided with two ends13substantially parallel to one another. The lower longeron8is also provided with two ends13substantially parallel to one another. As represented inFIGS.3,4Aand B, each of the ends13of the upper longeron7, respectively of the lower longeron8, is adapted to be positioned, in part or totally, in the notch17formed in each of the upper parts10A, respectively of the lower parts10B, of the internal panel9A and the external panel9B. In a preferred embodiment each of the ends13is formed of a contact face15to which at least a part of the abutment12is conformed.

Moreover, each of the ends13also includes a surface part14of the upper longeron7, respectively the lower longeron8. In a first embodiment that surface part14is not in contact with the lip11when the end13is positioned in the notch17. The lip11and the surface part14are spaced apart from one another. As represented inFIG.3, only the contact faces15of each of the ends13are in contact with the abutments12arranged facing them. In a second embodiment that surface part14is in contact with the lip11of the upper part10A, respectively lower part10B. The thickness of the upper longeron7in the vertical direction Z also represents the height of the contact face15in the vertical direction Z. Moreover, the abutment12is conformed to the contact face15so that the value of the height of the abutment12is substantially equal to the value of the height of the contact face15.

In a preferred embodiment the internal panel9A, the external panel9B and the upper longeron7, respectively the lower longeron8, are assembled by a weld that connects each end part10of the internal panel9A, external panel9B to the end13of the upper longeron7, lower longeron8with which it is in contact. The weld is a so-called edge-to-edge weld.

As represented inFIGS.4A and4Bthe weld produces a bead16that connects an end13of the upper longeron7(or the lower longeron8) to an end part10of the internal panel9A and to an end part10of the external panel9B. The weld also produces a heat-affected zone (not represented) common to the welded together end13and notch17. The bead16extends over a surface where the abutment12and the contact face15join. That junction surface is arranged in a plane substantially parallel to the plane in which the internal panel9A (respectively the external panel9B) extends. The weld bead16extends in the direction in which the longerons7and8extend, which correspond to the direction of the neutral fiber. Such an orientation enables fatigue of the bead16and consequently the risks of weakening of the weld to be minimized. This also limits the transfer of forces between the panels9A,9B and each longeron7,8. The weld bead16is not heavily loaded.

Moreover, in a preferred embodiment, each of the ends13of the upper longeron7, respectively the lower longeron8, is assembled by welding to an upper part10A, respectively a lower part10B. The welds are therefore produced in a symmetrical manner relative to the internal panel9A and the external panel9B so that deformations of the primary structure6in use are balanced. That balancing enables the risks of precocious appearance of weld faults to be minimized. It is therefore not necessary to use supplementary heat treatment to prevent precocious wear of certain parts of the primary structure6.

Moreover, the lip11of the notch17enables projection of welding materials into the primary structure6to be prevented.

In a first embodiment the bead16has a depth in a direction inclined relative to the vertical direction Z the minimum value of which may be less than or equal to the value of the height of the abutment12, as represented inFIG.4A. In this first embodiment the surface part14of the upper longeron7, respectively the lower longeron8, is in contact with the lip11of the notch17. In a variant of this first embodiment the surface part14is not in contact with the lip11, as represented inFIG.3.

In a second embodiment the bead16has a depth reaching the lip11, as represented inFIG.4B. The weld extends in the plane in which the lip11is arranged. In this second embodiment the surface part14of the longeron7,8may be in contact with the lip11. The weld then extends on the surface where the lip11is joined to the surface part14. In a variant of this second embodiment the surface part14is not in direct contact with the lip11. The surface part14and the lip11are spaced apart from one another, as represented inFIG.3.

When the weld is produced at the junction surface between the abutment12and the contact face15without the surface part14of the longeron7,7A,7B,8being in contact with the lip11, that enables a tolerance to be preserved for possible deformation of the primary structure6. On the other hand, when the surface part14of the longeron7,7A,7B,8is in contact with the lip11it is not possible to preserve a tolerance for deformation at the level of the weld.

The weld is produced over a small thickness so as to minimize the thermal energy introduced into the material that forms the upper longeron7and the lower longeron8and the internal panel9A and the external panel9B.

Moreover, as described hereinabove, the upper longeron7comprises the front upper longeron7A and the rear upper longeron7B. The front upper longeron7A and the rear upper longeron7B are arranged in planes at a non-zero angle.

In one particular embodiment the weld is produced continuously along the ends13of the front upper longeron7A and of the rear upper longeron7B. In another particular embodiment the weld is produced discontinuously along the end13in the direction in which the lower longeron8extends (in the longitudinal direction X) and the upper longeron7extends (in directions at an angle to the longitudinal direction X).

The weld is continuous in the vertical direction Z.

There is described hereinafter a method for welding a panel9A,9B to a longeron7,7A,7B,8as represented inFIG.5. That method includes the following steps:a step E1 of producing the notch17in each end part10of the internal panel9A and the external panel9B. The notch17is produced directly in the blanks of those panels9A and9B;a step E2 of positioning the end13of the longeron7,7A,7B,8in the notch17of the panel9A,9B; anda step E3 of edge-to-edge type welding of the end13to the notch17.

Moreover, the pylon1is of a design that simplifies the production of the primary structure6. The edge-to-edge welding of panels and longerons has the following advantages:a reduction of the mass of the primary structure6through the absence of bolt type fixing means and the absence of edges;saving the cost of the bolt type fixing means; andthe possibility of carrying out non-destructive testing during the production of the primary structure.

Moreover, the edge-to-edge weld enables reduction of raw material wastage. In fact, the notch17in which the weld is produced is formed directly in the blank of the panels9A,9B. Such a blank is of small size because of the absence of edges. Moreover, the longeron7,7A,7B,8necessitates no particular machining because it is positioned in the notch17.