PROPULSION UNIT FOR AIRCRAFT COMPRISING AN ENGINE, A MAST AND MEANS FOR ATTACHING THE ENGINE TO THE MAST

Abstract

PROPULSION ASSEMBLY FOR AIRCRAFT COMPRISING AN ENGINE, A MAST AND MEANS FOR ATTACHING THE ENGINE TO THE MAST The invention relates to a propulsion assembly for an aircraft and comprising an engine casing (112), a mounting mast (104), a first front engine attachment (152) with a pin (164) and a pallet (166) fitted onto the pin (164) and fixed in an articulated manner on either side of a median plane (P) to the casing (112) and a second front engine attachment (156) with a central connecting rod in the median plane (P) fixed in an articulated manner to a lower wall (106a) of the mounting mast (104) and to a fitting (206) of the casing (112), where the central connecting rod is generally parallel to a longitudinal axis (X). With such an arrangement, the casing is brought closer to the suspension mast for a gain in height. Fig. 2

Description

Title of the invention: PROPULSION ASSEMBLY FOR AIRCRAFT COMPRISING AN ENGINE, A MAST AND MEANS FOR ATTACHING THE ENGINE TO THE MAST Technical field

[0001] The present invention relates to the general field of attaching an engine under the wing of an aircraft. It relates in particular to a propulsion unit comprising an engine, for example of the double-flow turbojet type, a mast and a attachment assembly intended for attaching the engine under the mast. It also relates to an aircraft equipped with such a propulsion unit. STATE OF THE PRIOR ART

[0002] An aircraft conventionally comprises wings and at least one propulsion unit fixed under each of these wings. Each propulsion unit comprises a mounting pylon and an engine. The mounting pylon has a rigid structure called a "primary structure" which is fixed between the wing and the engine by means of mounting assemblies, namely a first mounting assembly between the wing and the mounting pylon and a second mounting assembly between the pylon and the engine.

[0003] The second attachment assembly comprises a front engine attachment and a rear engine attachment.

[0004] Patent application FR3113484 describes an engine assembly having a reduced vertical size because the front engine attachment is integrated into the mounting pylon. Such an engine assembly allowing the engine to be brought closer to the wing is particularly applicable to large fans, for which it is necessary to minimize the height of the front engine attachment to move the fan away from the ground.

[0005] Although such a motor assembly is efficient, there is a need to find a propulsion assembly solution which makes it possible to further minimize the height of the motor attachment. Statement of the invention

[0006] An object of the present invention is to provide a propulsion unit comprising an engine, a mast and a mounting device intended for mounting the engine under the mast, and which allows a reduction in the vertical distance between the wing and the engine.

[0007] For this purpose, a propulsion unit for an aircraft is proposed, said propulsion unit having a longitudinal axis and having a vertical median plane passing through the longitudinal axis and comprising:

[0008] - an engine comprising a casing,

[0009] - a suspension mast having a primary structure with a front wall and a lower wall,

[0010] - a first front engine attachment comprising a pin and a pallet, where the pin is cylindrical with a first end secured to the front wall of the primary structure of the attachment mast and a second end which projects forward, where the axis of the pin is parallel to the longitudinal axis and in the median plane, where the pallet has a bore passing through the pallet, the axis of which is parallel to the axis of the pin, where the bore of the pallet is fitted onto the pin, where the pallet is fixed in an articulated manner on either side of the median plane to the casing by means of a connection point to a front fitting secured to the casing, and

[0011] - a second front engine attachment comprising a central connecting rod arranged in the median plane, where a first end of the central connecting rod is hingedly attached to a first fitting integral with the lower wall of the primary structure, and where a second end of the central connecting rod is hingedly attached to a second fitting integral with the casing, where the central connecting rod is generally parallel to the longitudinal axis.

[0012] With such an arrangement, the casing is brought closer to the attachment mast for a gain in height.

[0013] Advantageously, for each connection point, the propulsion assembly comprises a complementary fixing point between the pallet and the front fitting, where each complementary fixing point is a standby safety point.

[0014] Advantageously, the first end of the central connecting rod is at the rear relative to the second end of the central connecting rod.

[0015] Advantageously, each connection point provides a ball joint connection of which a main axis of rotation is parallel to the longitudinal axis, and where the rotations along the other two axes are of reduced amplitude.

[0016] Advantageously, the articulation of the first end of the central connecting rod to the first fitting and the articulation of the second end of the central connecting rod to the second fitting take the form of pivot connections whose axes are perpendicular to the median plane.

[0017] Advantageously, the second front engine attachment comprises two lateral connecting rods arranged on either side of the median plane, a first end of each lateral connecting rod is fixed in an articulated manner to the first fitting and a second end of each lateral connecting rod is fixed in an articulated manner to the second fitting.

[0018] Advantageously, the pallet is made up of two sub-pallets placed next to each other.

[0019] Advantageously, the primary structure is made up of two parts joined to each other along the median plane, the pin is made up of two half-pins, where each takes the form of a half-cylinder, and each half-pion has a first end secured to a part of the primary structure and a second end which projects forward.

[0020] The invention also proposes an aircraft comprising a wing and a propulsion unit according to one of the preceding variants, the primary structure of which is fixed under the wing. Brief description of the drawings

[0021] The above-mentioned features of the invention, as well as others, will appear more clearly on reading the following description of an exemplary embodiment, said description being made in relation to the attached drawings, among which:

[0022] [Fig-1] represents a side view of an aircraft according to the invention,

[0023] [Fig.2] is a perspective view of a propulsion assembly according to the invention,

[0024] [Fig.3] is a perspective view of the propulsion assembly of [Fig.2], and

[0025] [Fig.4] is a bottom view of the propulsion assembly according to the invention in which the engine is not shown.

[0026] DETAILED DESCRIPTION OF EMBODIMENTS

[0027] With reference to [Fig.l], an aircraft 50 comprises a fuselage 51 to which is fixed, on each side, a wing 52 under which is mounted at least one propulsion unit 100 according to the invention.

[0028] The propulsion assembly 100 comprises a mounting mast 104 fixed under the wing 52 and an engine 102 fixed to the mounting mast 104 by means of a mounting assembly 180.

[0029] By convention, the longitudinal axis of the engine 102 and therefore of the propulsion unit 100 is called X, this longitudinal axis X being parallel to a longitudinal direction of this engine 102. On the other hand, the transverse axis of the engine 102 which is horizontal when the aircraft is on the ground is called Y, and the vertical axis or vertical height when the aircraft is on the ground is called Z, these three directions X, Y and Z being orthogonal to each other.

[0030] On the other hand, the terms "front" and "rear" are to be considered in relation to a direction of advancement of the aircraft 50 during operation of the engine 102, this direction being represented schematically by the arrow 107 in the figures.

[0031] The attachment mast 104 is, in Figs. 2 and 3, represented by its primary structure 106 extending in the longitudinal direction X between a front end and a rear end between which there is a median zone. The primary structure 106 is fixed under the wing 52.

[0032] In the embodiment of the invention presented here, the primary structure 106 takes the form of a beam which comprises a lower wall 106a, an upper wall 106b, two side walls 106c-d and a front wall 106e oriented towards the front.

[0033] The engine 102 comprises a casing 112 of cylindrical shape around the longitudinal axis X and which surrounds the elements of the heart of the engine.

[0034] The attachment mast 104 is generally symmetrical with respect to a vertical median plane XZ of the engine 102 which passes through the longitudinal axis X, which is subsequently called median plane P and which separates the attachment mast 104 into two port-starboard parts.

[0035] The attachment assembly 180 may comprise, at the rear of the attachment mast 104, a rear engine attachment as well as a device for absorbing engine thrust forces. The rear engine attachment is not shown in the figures, it may be of any type known to those skilled in the art and will not be described further.

[0036] According to the invention, and with reference to Figs. 2 and 3, the attachment assembly 180 comprises at the front of the attachment mast 104, a front engine attachment assembly which comprises a first front engine attachment 152 connecting the engine 102 to the front wall 106e of the attachment mast 104 and a second front engine attachment 156 connecting the lower wall 106a of the attachment mast 104 to the engine 102.

[0037] The first front engine attachment 152 is interposed directly between the front wall 106e of the attachment mast 104 and the casing 112 by means of a front fitting 153 secured to the casing 112, and more particularly to an upper part of the casing 112. In the embodiment of the invention presented in [Fig.2] and [Fig.3], there is a front fitting 153 which extends on either side of the median plane P, but this front fitting 153 can be divided into two separate front sub-fittings arranged on either side of the median plane P.

[0038] The first front engine attachment 152 comprises a pin 164 also called a “spigot” which is cylindrical and which has a first end secured to the front wall 106e and a second end which projects forward. The axis of the pin 164 is in the median plane P and parallel to the longitudinal axis X.

[0039] The first front engine attachment 152 also comprises a pallet 166. In the embodiment of the invention presented here, the pallet 166 is made up of two sub-pallets 166a-b attached to each other, and one behind the other along the longitudinal axis X with a rear pallet 166a and a front pallet 166b, and this for reasons of safety and doubling of the force paths in order to ensure that the connection is maintained even in the event of damage and loss of one of the elements of the connection. The technical characteristics which are described here for the pallet 166 apply as appropriate to each sub-pallet 166a-b.

[0040] The pallet 166, and therefore here each sub-pallet 166a-b, comprises a through bore and the axis of which is parallel to the axis of the pin 164 in the position of use of the first front engine attachment 152, that is to say when the first front engine attachment 152 is fixed to the attachment mast 104 and to the engine 102 and is operational to take up the forces of the engine 102. The bore of the pallet 166 and therefore each sub-pallet 166a-b is fitted onto the pin 164 ensuring freedom of rotation of the pallet 166 on the pin 164 around the axis of the pin, as well as around the transverse axis Y and around the vertical axis Z, the connection between the pin 164 and the bore of the pallet 166 being a ball joint connection.

[0041] The pallet 166 is, furthermore, fixed in an articulated manner to the front fitting 153, that is to say that the pallet 166 is fixed in an articulated manner on either side of the median plane P to the casing 112 by means of two connection points 167a-b to the front fitting 153 distributed to the port and starboard sides of the median plane P. There is thus a connection point 167a to the starboard side of the median plane P and a connection point 167b to the port side of the median plane P.

[0042] In the embodiment of the invention presented here, each connection point 167a-b of the pallet 166 to the front fitting 153 is constituted by a female yoke made in the front fitting 153, by a male yoke made by the pallet 166 (here the sub-pallets 166a-b), and by a front shear shaft 155 which is parallel to the longitudinal axis X and which passes through the female yoke and fits into the male yoke through a ball joint. For example, the front shear shaft 155 is equipped with a nut on which the male yoke is articulated to make the ball joint, thus each connection point 167a-b ensures a ball joint of which a main axis of rotation is parallel to the longitudinal axis X, and where the rotations along the other two axes are of reduced amplitudes.

[0043] The pin 164 allows the forces in Y and Z to be taken up in a frontal plane perpendicular to the longitudinal direction X.

[0044] The front fittings 153, the pallet 166 and the pin 164 define a primary force path.

[0045] The second front engine attachment 156 is interposed directly between the middle zone of the primary structure 106, here the lower wall 106a, and the casing 112, and more particularly an upper part of the casing 112. The second front engine attachment 156 comprises a first fitting 204 secured to the lower wall 106a of the primary structure 106 and a second fitting 206 secured to the casing 112.

[0046] The second engine attachment 156 comprises a central connecting rod 158 which is in the median plane P, where a first end of the central connecting rod 158 is fixed in an articulated manner to the first fitting 204, and where a second end of the central connecting rod 158 is fixed in an articulated manner to the second fitting 206.

[0047] The central connecting rod 158 is generally parallel to the longitudinal axis X, that is to say that the point of articulation of the first end to the first fitting 204 and the point of articulation of the second end to the second fitting 206 are generally in the same plane perpendicular to the median plane P.

[0048] In the embodiment of the invention presented here, each articulation point of the central connecting rod 158 to the first fitting 204 and to the second fitting 206, is a pivot connection around axes of rotation 157a and 159a perpendicular to the median plane P.

[0049] In the embodiment of the invention presented here, each point of articulation of the central connecting rod 158 is constituted by a female yoke produced respectively in the first fitting 204 and the second fitting 206, by a male yoke produced by the central connecting rod 158, and respectively by a rear shear shaft 157 and a front shear shaft 159 which are perpendicular to the median plane P, and where each passes through the female yoke and fits into the corresponding male yoke to form the pivot connection around the axis of rotation 157a, 159a considered.

[0050] The central connecting rod 158 allows forces to be taken up along the longitudinal axis X. Here, each shear shaft 157, 159 is a double shaft, i.e. with an inner shaft inserted into an outer shaft to compensate for any failure of the outer shaft.

[0051] The axes of rotation 157a and 159a are parallel to each other and perpendicular to the median plane P and they are inscribed in a rear plane P' which is perpendicular to the plane P and generally parallel to the longitudinal axis X.

[0052] With such an arrangement, the casing 112 can be brought closer to the attachment mast 104 for a gain in height.

[0053] In the embodiment of the invention presented herein, the first end of the central connecting rod 158 is rearward relative to the second end of the central connecting rod 158.

[0054] For safety reasons, for each connection point 167a-b, the propulsion assembly 100 comprises a complementary fixing point 169a-b between the pallet 166 and the front fitting 153. The two complementary fixing points 169a-b are arranged on either side of the median plane P and here outside the connection points 167a-b.

[0055] Each complementary fixing point 169a-b forms between the pallet 166 and the front fitting, a pivot connection around an axis of rotation parallel to the longitudinal axis X, where the front fitting 153 forms the female yoke in which the pallet 166 forming the male yoke is inserted, and where a complementary shear shaft 151 parallel to the longitudinal axis X passes through the female yoke and fits into the male yoke.

[0056] Each complementary attachment point 169a-b is a standby safety point which is activated only in the event of a break in one of the elements of the connection. This is achieved, for example, in such a way that each complementary shear shaft 151 is mounted without play in the female yoke and with play in the male yoke. Thus, in normal operation of the attachment assembly 180, there is neither contact between the complementary shear shaft 151 and the male yoke, nor transfer of forces through the complementary fixing points 169a-b and in degraded operation, the front fitting 153 and / or the pallet 166 can move so as to bring at least one of the complementary shear shafts 151 of the complementary fixing points 169a-b against the male yoke to transfer forces.

[0057] In the embodiment of the invention presented here, the second front engine attachment 156 comprises two lateral connecting rods 158a-b arranged on either side of the median plane P and here on either side of the central connecting rod 158.

[0058] For each side rod 158a-b, a first end of said side rod 158a-b is hingedly attached to the first fitting 204 and a second end of said side rod 158a-b is hingedly attached to the second fitting 206. According to a first configuration, the attachment of the side rod 158a-b to the second fitting 206 is a standby safety point. According to a second configuration, the side rod 158a-b is mounted in the second fitting 206 and is without play.

[0059] The articulation points of the first end of each lateral connecting rod 158a-b and of the first end of the central connecting rod 158 are merged and each provide a pivot connection around the same axis of rotation 157a and the articulation points of the second end of each lateral connecting rod 158a-b and of the second end of the central connecting rod 158 are merged and each provide a pivot connection around the same axis of rotation 159a.

[0060] As best seen in Figs. 3 and 4, the first fitting 204 is made up of four parallel walls 204a-d secured to the lower wall 106a. The four walls 204a-d are spaced apart from each other and between two successive walls 204a-d, a lateral connecting rod 158a-b or the central connecting rod 158, is inserted.

[0061] The second fitting 206 has the same structure with four parallel walls secured to the casing 112, where the connecting rods 158 and 158a-b are inserted between two successive walls.

[0062] The shear shafts 157 and 159 pass through the various connecting rods 158 and 158a-b and the walls concerned.

[0063] In the embodiment of the invention presented here, the primary structure 106 is made up of two parts 107a-b joined to each other along the median plane P, which makes it possible to guarantee a transfer of forces even if one of the two parts 107a-b is defective.

[0064] At the same time, the pin 164 is made up of two half-pins 164a-b, where each takes the form of a half-cylinder, and each half-pin 164a-b has a first end secured to a part 107a-b of the primary structure 106 and a second end which projects forward.

[0065] The two half-cylinders are joined and arranged against each other to form the pawn 164.

[0066] The installation of two half-pins 164a-b makes it possible to guarantee a force path even in the event of breakage of one of the half-pins 164a-b.

Claims

Claims

1. Propulsion assembly (100) of an aircraft (50), said propulsion assembly (100) having a longitudinal axis (X) and having a vertical median plane (P) passing through the longitudinal axis (X) and comprising: - an engine (102) having a casing (112), - an attachment pylon (104) having a primary structure (106) with a front wall (106e) and a lower wall (106a), - a first front engine attachment (152) comprising a pin (164) and a vane (166), where the pin (164) is cylindrical with a first end secured to the front wall (106e) of the primary structure (106) of the attachment pylon (104) and a second end which projects forward, where the axis of the pin (164) is parallel to the longitudinal axis (X) and in the median plane (P), where the pallet (166) has a bore passing through the pallet (166), the axis of which is parallel to the axis of the pin (164), where the bore of the pallet (166) is fitted onto the pin (164),where the pallet (166) is fixed in an articulated manner on either side of the median plane (P) to the casing (112) by means of a connection point (167a-b) to a front fitting (153) secured to the casing (112), and - a second front engine attachment (156) comprising a central connecting rod (158) arranged in the median plane (P), where a first end of the central connecting rod (158) is fixed in an articulated manner to a first fitting (204) secured to the lower wall (106a) of the primary structure (106), and where a second end of the central connecting rod (158) is fixed in an articulated manner to a second fitting (206) secured to the casing (112), where the central connecting rod (158) is generally parallel to the longitudinal axis (X).,

2. Propulsion assembly (100) according to claim 1, characterized in that for each connection point (167a-b), the propulsion assembly (100) comprises a complementary fixing point (169a-b) between the pallet (166) and the front fitting (153), where each complementary fixing point (169a-b) is a standby safety point.

3. Propulsion assembly (100) according to one of claims 1 to 2, characterized in that the first end of the central connecting rod (158) is at the rear relative to the second end of the central connecting rod (158).

4. Propulsion assembly (100) according to one of claims 1 to 3, characterized in that each connection point (167a-b) provides a ball joint connection of which a main axis of rotation is parallel to the longitudinal axis (X), and where the rotations along the other two axes are of reduced amplitude.

5. Propulsion assembly (100) according to one of claims 1 to 4, characterized in that the articulation of the first end of the central connecting rod (158) to the first fitting (204) and the articulation of the second end of the central connecting rod (158) to the second fitting (206), take the form of pivot connections whose axes (157a, 159a) are perpendicular to the median plane (P).

6. Propulsion assembly (100) according to claim 5, characterized in that the second front engine attachment (156) comprises two lateral connecting rods (158a-b) arranged on either side of the median plane (P), in that a first end of each lateral connecting rod (158a-b) is fixed in an articulated manner to the first fitting (204) and in that a second end of each lateral connecting rod (158a-b) is fixed in an articulated manner to the second fitting (206).

7. Propulsion assembly (100) according to one of claims 1 to 6, characterized in that the pallet (166) consists of two sub-pallets (166a-b) attached to each other.

8. Propulsion assembly (100) according to one of claims 1 to 7, characterized in that the primary structure (106) is made up of two parts (107a-b) joined to each other along the median plane (P), in that the pin (164) is made up of two half-pins (164a-b), where each takes the form of a half-cylinder, and in that each half-pin (164a-b) has a first end secured to a part (107a-b) of the primary structure (106) and a second end which projects forward.

9. Aircraft (100) comprising a wing (52) and a propulsion unit (100) according to one of the preceding claims, the primary structure (106) of which is fixed under the wing (52).

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