FRONT ENGINE MOUNTING SYSTEM FOR A COMPACT AIRCRAFT ENGINE

Description

TECHNICAL FIELD

[0001] The present invention relates to a front engine mounting system for an aircraft engine where the front engine mounting system is compact, as well as an aircraft comprising at least one such front engine mounting. PREVIOUS STATE OF THE ART

[0002] An aircraft typically has at least one engine, in particular a turbojet. Under each wing and for each engine, the aircraft has an engine pylon which is attached to the wing structure and extends below the wing, and the engine is suspended below the engine pylon.

[0003] The engine is housed in a nacelle and attached to the reactor mast via an engine attachment system comprising a front engine attachment and a rear engine attachment.

[0004] There are many types of front engine mounts that are satisfactory for their current use. However, the fans on newer engines are increasingly larger to improve engine performance, which reduces the distance between the nacelle and the ground.

[0005] It is therefore necessary to define a new arrangement to reduce the height of the front engine mount, thereby moving the nacelle further from the ground and consequently bringing the nacelle closer to the wing. Document FR 3098793 A1 describes a front engine mount for an aircraft engine connecting a primary structure and a fan casing.This attachment comprises: a plate connected to the primary structure, at least one transverse link connecting the plate and the blower housing by means of first and second longitudinal links having first and second longitudinal pivot axes approximately parallel to a longitudinal direction, at least one of the first and second longitudinal links incorporating a ball joint, at least one longitudinal link connecting the plate and the blower housing by means of first and second transverse links having first and second transverse pivot axes approximately parallel to a horizontal transverse direction perpendicular to the longitudinal direction, at least one of the first and second transverse links incorporating a ball joint. DESCRIPTION OF THE INVENTION

[0006] One object of the present invention is to propose a front engine attachment system which integrates the reactor mast and the front engine attachment to reduce the overall height.

[0007] For this purpose, a front engine mounting system is proposed according to claim 1.

[0008] Such a forward engine attachment system has a reduced vertical footprint because the forward engine attachment is integrated into the reactor mast.

[0009] Advantageously, the main axis is positioned in front of the vertical axis.

[0010] According to a particular embodiment, the front engine attachment system comprises an inner cylinder inserted and fixed within the outer cylinder.

[0011] According to another particular embodiment, the nose has two lateral stops arranged respectively to port and starboard of the outer cylinder and which are intended to come between two lateral counter-stops of the front casing.

[0012] Advantageously, the forward engine mounting system comprises two lateral connecting rods arranged respectively to the port and starboard sides of the main connecting rod, and each lateral connecting rod is mounted on the main shaft with an interference fit and on the secondary shaft with clearance. Advantageously, the main shaft consists of a hollow outer shaft and an inner shaft housed within the outer shaft.

[0013] Advantageously, the secondary tree consists of a peripheral tree which is hollow and an inner tree which is housed within the peripheral tree.

[0014] The invention also proposes an aircraft comprising a structure, an engine with a front casing and a front engine attachment system according to one of the preceding variants, where the main connecting rod is fixed to the front casing by the secondary ball joint and where the second end of the outer cylinder is mounted movably through the annular linear link around the vertical axis relative to the front casing. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The features of the invention mentioned above, as well as others, will become clearer upon reading the following description of an exemplary embodiment, said description being made in relation to the accompanying drawings, among which: Fig. 1 is a side view of an aircraft according to the invention, Fig. 2 is a perspective view of a front engine mounting system according to the invention, Fig. 3 is a perspective view of a cross-section of the front engine mounting system according to the invention at line III of the Fig. 2 , Fig. 4 is a perspective view of a cross-section of the front engine mounting system according to the invention at line IV of the Fig. 2 Fig. 5 is a view similar to the Fig. 4 for an alternative implementation. DETAILED EXPLANATION OF IMPLEMENTATION METHODS

[0016] In the following description, terms relating to a position are taken with reference to an aircraft in a forward position, that is, as it is represented on the Fig. 1 , where arrow F represents the direction of advancement.

[0017] There Fig. 1 shows an aircraft 100 which has an engine 102, in particular a turbojet which is fixed under a reactor mast 104 itself fixed under a wing 106.

[0018] In the following description, and by convention, X is called the longitudinal direction of the engine 102 oriented positively in the direction of forward movement of the aircraft 100, Y is called the transverse direction of the engine 102 which is horizontal when the aircraft 100 is on the ground, and Z is called the vertical direction or vertical height when the aircraft 100 is on the ground, these three directions X, Y and Z being orthogonal to each other.

[0019] The motor 102 generally exhibits a form of revolution around the longitudinal axis X. In the embodiment of the invention presented in the Fig. 1 , aircraft 100 has one engine 102 under each wing 106 of aircraft 100, but it is possible to provide several engines under each wing 106.

[0020] There Fig. 2 shows a forward engine mounting system 150 which is attached to the aircraft structure 100, here the wing structure 106, and extends under the wing 106 and supports the engine 102 and in particular the forward part of the engine 102. Figs. 2 à 4 show different views of the front engine mounting system 150.

[0021] The forward engine attachment system 150 includes the engine pylon 104 attached to the wing structure 106 and a forward engine attachment 160 fixed between the engine pylon 104 and a forward casing 103 integral with the engine 102. The forward engine attachment system 150 includes a vertical midplane XZ.

[0022] Typically, a rear engine attachment is fixed between the reactor mast 104 and a rear part of the engine 102 and it can take any form known to a person skilled in the art.

[0023] The reactor mast 104 takes the form of a box which includes, among other things, at the level of a front part 163, a nose 110 which has a main female clevis 111 made up of two walls 110a-b which are parallel to each other and vertical, that is to say parallel to the median plane XZ and therefore perpendicular to the transverse direction Y. As specified below, the main female clevis 111 allows the installation of a connecting rod which is mounted freely in rotation in the main female clevis 111 around a main axis 10 oriented transversely, that is to say perpendicular to the median plane XZ and therefore horizontally so as to make a ball joint called main joint whose main axis of rotation is the main axis 10 and where the rotations about the other two axes are of reduced amplitudes.

[0024] In the embodiment of the invention presented on the Figs. 2 à 5 , the nose 110 consists of two fittings 109a-b fixed to each other at the median plane XZ and each wall 110a-b constituting the main female clevis 111 belongs to one of the fittings 109a-b, and the two walls 110a-b are here symmetrical with respect to the median plane XZ.

[0025] There Fig. 3 shows a cross-section at the level of the main female clevis 111 and a secondary female clevis 103a.

[0026] The reactor mast 104 comprises an upper wall 104a, a lower wall 104b, and two side walls 104c-d. The various walls 104a-d are joined together to form a box-shaped structure with a generally trapezoidal vertical cross-section. The nose cone 110 is attached to the forward section 163 of the reactor mast 104 by any known means, such as welding or bolts. The forward section 163 corresponds to the forward ends of the walls 104a-d.

[0027] The front engine mount 160 comprises a main connecting rod 162 fixed to the nose 110 within the main female bracket 111. The main ball joint connection of the main connecting rod 162 within the main female bracket 111 is achieved by a main shaft 165, which is equipped with a nut 171 on which the main connecting rod 162 is articulated. The main shaft 165 passes through the two walls 110a-b forming the main female bracket 111 and the main connecting rod 162 via bores provided for this purpose. The main shaft 165 is thus perpendicular to the median plane XZ. The main axis 10 constitutes the axis of the main shaft 165.

[0028] The main connecting rod 162 is also hinged to the front housing 103 by a secondary ball joint. One of the secondary axes of rotation of this secondary axis is a secondary axis 12 perpendicular to the median plane XZ, and therefore horizontal, and the rotations about the other two axes are of limited amplitude. To this end, the front housing 103 has a secondary female yoke 103a, which is also made of two parallel and vertical walls, i.e., parallel to the median plane XZ and symmetrical with respect to the median plane XZ. The main connecting rod 162 is attached to the secondary female yoke 103a by a secondary shaft 167 that passes through the two walls forming the secondary female yoke 103a and the main connecting rod 162 via bores provided for this purpose. The secondary shaft 167 is thus perpendicular to the median plane XZ. Secondary axis 12 constitutes the axis of secondary tree 167.The secondary ball joint connection of the main connecting rod 162 with the front casing 103 is made by the secondary shaft 167 which is equipped with a nut 174 on which the main connecting rod 162 is articulated.

[0029] The secondary axis 12 is aligned vertically with the main axis 10 and below the latter, that is to say that the axis of the secondary shaft 167 and the axis of the main shaft 165 are in the same vertical plane perpendicular to the longitudinal direction X and therefore to the median plane XZ, or in other words that the main axis of the main ball joint, that is to say the main axis 10, and the main axis of the secondary ball joint, that is to say the secondary axis 12, are in the same vertical plane perpendicular to the median plane XZ.

[0030] In the embodiment of the invention presented to the Fig. 3 The main connecting rod 162 is mounted with an interference fit via nuts 171 and 174 on the main shaft 165 and on the secondary shaft 167. The main shaft 165 is mounted inside the bores of the main female yoke 111 by means of rotary bearings. The secondary shaft 167 is mounted inside the bores of the secondary female yoke 103a with an interference fit.

[0031] There Fig. 4 shows a cross-section at the level of an annular linear joint where the axis of translation is a vertical axis 20 also called a "spigot joint" 169.

[0032] The nose 110 has a cylindrical housing 502 coaxial with the vertical axis 20 which is therefore oriented vertically and here in the vertical median plane XZ.

[0033] The front engine attachment 160 also includes an external cylinder 504, one end of which is fixed in the cylindrical housing 502 so that the external cylinder 504 is coaxial with the vertical axis 20.

[0034] The second end of the outer cylinder 504 is mounted movably via an annular linear link around the vertical axis 20 relative to the front casing 103. There is therefore a ball joint around a main axis, which is the vertical axis 20, between the outer cylinder 504 and the front casing 103, and thus between the nose 110 and the front casing 103. There is also a sliding joint whose direction is parallel to the vertical axis 20.

[0035] In the embodiment of the invention presented to the Fig. 4 The ball joint connection is achieved by fitting a nut 506 mounted around the outer cylinder 504 on which the front housing 103 is articulated. The nut 506 is between the outer cylinder 504 and the front housing 103 in which a bore 508 is made to allow the fitting of the nut 506 and the second end of the outer cylinder 504.

[0036] The sliding connection is made between the cylindrical block 502 and the nut 506, which is therefore mounted freely in translation along the cylindrical block 502 parallel to the vertical axis 20. In the embodiment of the invention presented in the Fig. 4 The outer cylinder 504 is hollow, and the front engine mount 160 also includes an inner cylinder 505 which is inserted and fixed within the outer cylinder 504. The inner cylinder 505 is therefore also coaxial with the vertical axis 20. The outer diameter of the inner cylinder 505 is smaller than the inner diameter of the outer cylinder 504 to create a space 507 between them, i.e., between the inside of the outer cylinder 504 and the outside of the inner cylinder 505. The difference in diameter is, for example, on the order of 0.6 mm to 2 mm and preferably 1 mm.

[0037] In the embodiment of the invention presented to the Fig. 4 The first end of the outer cylinder 504 and the inner cylinder 505 are fixed by inserting a pin 503 which is embedded in a bore that passes through the outer cylinder 504, the inner cylinder 505, and the nose 110. The axis of the pin 503 is perpendicular to the vertical axis 20. In the embodiment of the invention presented in the Fig. 5 , only the outer cylinder 504 is full here.

[0038] The main female clevis 111 is arranged in front of the spigot joint 169 with respect to the longitudinal direction X, i.e. the main axis 10 of the main ball joint is in front of the vertical axis 20.

[0039] With such an arrangement, the mast 104 directly incorporates the elements ensuring the attachment of the motor 102 in order to reduce the height required for this attachment.

[0040] When the engine 102 is in operation, forces are generated and they are transmitted to the wing structure through the forward casing 103 and the forward engine attachment system 150, i.e. through the main connecting rod 162, the secondary shaft 167, the main shaft 165, the spigot link 169 and the reactor mast 104 which form a primary path of forces.

[0041] The Z-forces are thus transmitted through the secondary ball joint and the main ball joint, i.e. vertically through the main connecting rod 162.

[0042] The forces in X and Y are transmitted through the spigot joint 169.

[0043] For safety reasons, the 150 front engine attachment system also includes means that ensure secondary paths of forces that compensate for a failure of the primary path of forces, these means constituting waiting fail-safe means.

[0044] In the embodiment of the invention presented to the Fig. 5 In the event of failure at the level of the spigot joint 169, it is necessary to continue to transmit the Y-forces. Thus, according to a particular embodiment of the invention, the nose 110 then comprises two lateral stops 512a-b which are arranged respectively to port and starboard of the outer cylinder 504 and, for each lateral stop 512a-b, the front casing 103 comprises a lateral counter-stop 510a-b and the two lateral counter-stops 510a-b are also arranged respectively to port and starboard of the outer cylinder 504 and the lateral stops 512a-b are arranged between the lateral counter-stops 510a-b.

[0045] In normal position, i.e. without failure of the primary path of forces, each lateral stop 512a-b is at a distance from the associated lateral counter-stop 510a-b, and in case of failure, one of the lateral stops 512a-b comes to rest against the associated lateral counter-stop 510a-b.

[0046] In the embodiment of the invention presented to the Fig. 4 In the event of a break in the outer cylinder 504, the inner cylinder 505 takes over and thus forms a waiting fail-safe.

[0047] In case of failure, it is necessary to continue transmitting the forces in the Z direction. Thus, according to a particular embodiment of the invention, the forward engine mounting system 150 comprises two lateral connecting rods 170a-b arranged respectively to the port and starboard sides of the main connecting rod 162, and in the embodiment of the invention presented in Figs. 2 And 3 , respectively to port and starboard of the walls 110a-b forming the main female slab 111 and symmetrically with respect to the median plane XZ.

[0048] Each connecting rod 170a-b is mounted on the main shaft 165 with an interference fit and on the secondary shaft 167 with clearance. Thus, in certain failure scenarios, at least one connecting rod 170a-b and / or the secondary shaft 167 will move, bringing the inner wall of the bore of said connecting rod 170a-b against the secondary shaft 167.

[0049] In the embodiment of the invention presented to Figs. 2 And 3 The main shaft 165 consists of a peripheral shaft 165a which is cylindrical and hollow and an inner shaft 165b which is housed within the peripheral shaft 165a. Such an arrangement makes it possible to compensate for a possible breakage of the peripheral shaft 165a.

[0050] In the embodiment of the invention presented to Figs. 2 And 3The secondary shaft 167 consists of a peripheral shaft 167a which is cylindrical and hollow and an inner shaft 167b which is housed within the peripheral shaft 167a. Such an arrangement makes it possible to compensate for a possible breakage of the peripheral shaft 167a.

Claims

1. Front engine attachment system (150) for an engine (102) of an aircraft (100), the front engine attachment system (150) having a vertical median plane (XZ) and having: - an engine pylon (104) having at a front part, a nose (110) having a main female clevis (111) - a main rod (162) intended to be fastened to a front casing (103) of the engine (102) by a secondary ball joint connection about a secondary axis (12) perpendicular to the median plane (XZ) by way of a secondary shaft (167), - a main shaft (165) perpendicular to the median plane (XZ) and realizing a main ball joint connection of the main rod (162) in the main female clevis (111) about a main axis (10), wherein the main axis (10) and the secondary axis (12) are in one and the same vertical plane perpendicular to the median plane (XZ), the front engine attachment system (150) being characterized in that the nose (110) has a cylindrical housing (502) around a vertical axis (20) and in that the system comprises: - an outer cylinder (504) coaxial with the vertical axis (20), of which a first end is fastened in the cylindrical housing (502) and of which a second end is intended to be mounted so as to be able to move, via an annular linear connection, about the vertical axis (20) with respect to the front casing (103).

2. Front engine attachment system (150) according to Claim 1, characterized in that the main axis (10) is disposed in front of the vertical axis (20).

3. Front engine attachment system (150) according to one of Claims 1 or 2, characterized in that it has an inner cylinder (505) inserted and fastened in the outer cylinder (504).

4. Front engine attachment system (150) according to one of Claims 1 or 2, characterized in that the nose (110) has two lateral stops (512a-b) disposed respectively on the port side and on the starboard side of the outer cylinder (504) and which are intended to come between two lateral counter-stops (510a-b) of the front casing (103).

5. Front engine attachment system (150) according to one of Claims 1 to 4, characterized in that it has two lateral rods (170a-b) disposed respectively on the port side and on the starboard side of the main rod (162), and in that each lateral rod (170a-b) is mounted on the main shaft (165) with a tight fit and on the secondary shaft (167) with a clearance.

6. Front engine attachment system (150) according to one of Claims 1 to 5, characterized in that the main shaft (165) is constituted of a peripheral shaft (165a) that is hollow and an inner shaft (165b) that is housed in the peripheral shaft (165a).

7. Front engine attachment system (150) according to one of Claims 1 to 6, characterized in that the secondary shaft (167) is constituted of a peripheral shaft (167a) that is hollow and an inner shaft (167b) that is housed in the peripheral shaft (167a).

8. Aircraft (100) having a structure, an engine (102) with a front casing (103) and a front engine attachment system (150) according to one of preceding Claims, wherein the main rod (162) is fastened to the front casing (103) by the secondary ball joint connection and wherein the second end of the outer cylinder (504) is mounted so as to be able to move, via the annular linear connection, about the vertical axis (20) with respect to the front casing (103).