Connecting element comprising a sacrificial ball joint, in particular for an engine support

Abstract

A connecting element 1 has two ball joints 3a,3b mounted on a body 2. Fixed to the body by a device, the body supports a third sacrificial ball joint 3c having an outer ring (fig.2,4) with a spherica

Description

Title: Connecting element comprising a sacrificial ball joint, in particular for an engine support Technical field of the invention The present invention relates to the field of connecting elements employing ball joints, in particular connecting elements for supporting an engine. An aircraft engine is generally supported by a pylon that connects the engine to the wing or to the fuselage of the aircraft. The pylon is connected to the engine via connecting elements employing ball joints. The ball joints give the system freedom of movement; in particular, the connecting element allows the system to be flexible, according to the thermal expansions of the engine. Some connecting elements comprising two ball joints can rotate without restraint along their axis of elongation, which is orthogonal to the axis of rotation of the ball joints. The rotation is due to micro-movements and vibrations caused mainly by friction. The connecting element is thus able to move randomly and to collide with surrounding parts, such as the engine suspension yoke. These collisions between the connecting element and the surrounding parts can lead to wear and failure. Prior art In order to localize such collisions in unloaded zones of a connecting element, overthicknesses may be provided on one of the front surfaces of the body of the connecting element that supports the ball joints. This solution is effective in protecting the body of the connecting element and the ball joints mounted thereon, but not in protecting the surrounding parts. Summary of the invention The invention aims to remedy this drawback. The invention relates to a connecting element, in particular for supporting an engine, comprising a body and a first ball joint and a second ball joint which are mounted on the body. The connecting element comprises a sacrificial third ball joint which is distinct from the first and second ball joints and is supported by the body and which comprises an outer ring and an inner ring having a spherical inner surface and a spherical outer surface, respectively, in contact with one another. The outer ring projects laterally on either side of the body. According to a general feature, the connecting element further comprises a device for fixing said sacrificial ball joint to said body. Thus, the outer ring of the third ball joint forms a sacrificial ring which is intended to come into contact with the surrounding part or parts after the connecting element has been assembled. This limits the contact between, on the one hand, the surrounding part or parts and, on the other hand, the body and the first and second ball joints of the connecting element. The outer ring can easily be replaced in the event of wear, without dismantling the connecting element. Advantageously, the outer surface of the outer ring of the sacrificial ball joint comprises at least one planar face, and preferably two opposing planar faces. Preferably, at least the outer surface of the outer ring of the sacrificial ball joint comprises a bronze coating and / or cobalt alloy coating. According to one embodiment, the body of said connecting element comprises an elongate portion in which the first and second distinct ball joints are located and a protruding portion projecting transversely with respect to the elongate portion and supporting the sacrificial ball joint. According to a particular design, the fixing device comprises a threaded shaft, which extends through the inner ring of the sacrificial ball joint and is inserted into a recess in the body, and a clamping washer mounted on the shaft and interposed between the inner ring of the sacrificial ball joint and the body. According to another design, the fixing device comprises a thread formed on the body, or on a shaft connected to the body, and on which the inner ring of the sacrificial ball joint is fixed. The fixing device may further comprise a groove formed on the body or on the shaft in the extension of the thread and inside which a protrusion of the inner ring of the sacrificial ball joint is housed. Alternatively or in combination, the fixing device may further comprise a nut for locking the sacrificial ball joint, the nut being mounted on the body or on the shaft. Advantageously, the first and second ball joints comprise two parallel axes of rotation and the sacrificial ball joint comprises an axis of rotation orthogonal to said axes. Optionally, a first main face of the body comprises a nickel and / or cobalt alloy and an opposing second main face of the body comprises a titanium and / or nickel alloy. Brief description of the figures Other aims, features and advantages of the invention will become apparent on reading the following description, which is given purely by way of non-limiting example and with reference to the appended drawings, in which: [Fig. 1] is a perspective view of a connecting element according to a first exemplary embodiment of the invention; [Fig. 2] is a detail view of a ball joint of the connecting element of Figure 1; [Fig. 3] is a perspective view of the connecting element of Figure 1; [Fig. 4] is a partial cross-sectional view of the connecting element of Figure 1; [Fig. 5] is a partial perspective view of the connecting element of Figure 1 according to one variant; and [Fig. 6] is a partial cross-sectional view of a connecting element of Figure 1 according to a second exemplary embodiment of the invention. Detailed description of the invention Figure 1 illustrates a connecting element, denoted by the reference numeral 1, comprising a body 2 and three ball joints 3a, 3b, 3c which are distinct from one another and mounted on said body 2. The connecting element 1 is represented in an orthonormal reference grid X, Y, Z, in which X denotes the transverse direction of the connecting element 1, the axis Y denotes the direction normal to the transverse axis X and the axis Z denotes the longitudinal direction of the connecting element 1. The body 2 of the connecting element 1 is provided with two opposing main faces A, B which define its thickness. The body 2 comprises an elongate portion 2a which extends in the longitudinal direction Z and a protruding portion 2b projecting transversely in the direction Y with respect to the elongate portion 2a. The elongate portion 2a and the protruding portion 2b define the main faces A, B. The connecting element 1 comprises a first ball joint 3a mounted in a lower zone of the elongate part 2a and a second ball joint 3b mounted in an upper zone of the elongate part 2a. The first and second ball joints 3a, 3b are spaced apart from each other in the longitudinal direction Z. Each ball joint 3a, 3b is mounted inside a recess passing through the body. Each ball joint 3a, 3b comprises a ring mounted inside the associated recess. Each ball joint 3a, 3b comprises a convex spherical outer surface in contact with the inner surface of the associated recess in the body 2. The connecting element 1 further comprises a third ball joint 3c, called sacrificial ball joint 3c, mounted on the protruding part 2b projecting from the body 2 of the connecting element 1. The first and second ball joints 3a, 3b comprise two parallel axes of rotation RI extending in the direction X and the sacrificial ball joint 3c comprises an axis of rotation R2 extending in the direction Y. The axis of rotation R2 is orthogonal to the axes of rotation RI. As will be described in greater detail below, the connecting element 1 further comprises a device for fixing said sacrificial ball joint 3c to said body 2, in particular to said protruding part 2b of the body. As illustrated more visibly in Figure 2, the sacrificial ball joint 3c of the connecting element comprises an outer ring 4 and an inner ring 5 in contact with one another. The outer ring 4 comprises a concave spherical inner surface 4a or a bore, an outer surface 4b radially opposing the inner surface 4a, and two opposing radial front faces (not referenced) axially defining the inner surface 4a and outer surface 4b. The inner ring 5 comprises a convex spherical outer surface 5b on which the inner surface 4a of the outer ring 4 is mounted, a cylindrical bore 5a radially opposite the outer surface 5b, and two opposing radial front faces (not referenced) axially defining the bore 5a and the outer surface 5b. The spherical inner 4a and outer 5b surfaces of the outer 4 and inner 5 rings are in contact with one another and have complementary shapes. The outer surface 4b of the outer ring 4 of the sacrificial ball joint 3c here comprises two opposing planar faces 6. These planar faces 6 each make it possible to create a connection of the planar bearing type for the walls of the surrounding part of the engine system, as illustrated in Figure 3. The outer ring 4 of the sacrificial ball joint projects laterally on either side of the body 2. The outer ring 4 projects laterally on either side of the body 2 in the direction Y. The outer ring 4 projects on one side with respect to the main face A of the body 2, and projects on the other side with respect to the opposing main face B of said body. The outer ring 4 thus forms a sacrificial ring which is designed to come into contact with the walls of the surrounding part of the engine system, and to avoid contact between this part, on the one hand, and the body 2 and the ball joints 3a, 3b, on the other. Advantageously, the outer surface 4b of the outer ring 4 of the sacrificial ball joint 3c comprises a bronze coating and / or cobalt alloy coating. In the exemplary embodiment illustrated in Figures 1, 3 and 4, the device for fixing the sacrificial ball joint 3c to the body 2 comprises a thread 7 formed on the body 2. The thread 7 is formed on the protruding part 2b of the body. The inner ring 5 of the sacrificial ball joint 3c is fixed by screwing onto the thread 7 and for this purpose comprises a corresponding tapping in its bore. The fixing device further comprises a groove 8 formed on the body 2 in the extension of the thread 7 and inside which a protrusion of the inner ring 5 of the sacrificial ball joint 3c is housed. The groove 8 also makes it possible to clip the inner ring 5 of the sacrificial ball joint 3c onto the body 2. In a variant as illustrated in Figure 5, the fixing device could comprise a nut 12 for locking the sacrificial ball joint 3c, this nut being mounted on the thread 7 of the body 2, the bore of the inner ring 5 in this case not being tapped and the fixing device not having the groove 8. The fixing device further comprises a clamping washer 11 mounted on the thread 7 of the body 2 and interposed between the inner ring 5 of the sacrificial ball joint 3c and the nut 12. The nut 12 and the clamping washer 11 make it possible to lock the inner ring 5 of the sacrificial ball joint 3c against the body 2 and consequently to lock the sacrificial ball joint 3c against the body 2. In the two embodiments described above, the thread 7 of the fixing device is formed directly on the body. Alternatively, it could be possible to provide the thread on a shaft connected to the body 2. In the exemplary embodiment illustrated in Figure 6, in which identical elements bear the same references, the device for fixing the sacrificial ball joint 3c to the body 2 comprises a threaded shaft 9 connected to the body 2 which extends through the bore of the inner ring 5 of the sacrificial ball joint 3c. The protruding portion 2b of the body 2 of the connecting element 1 comprises a recess 10 in which the connected threaded shaft 9 is force-fitted. The fixing device further comprises a clamping washer 11 mounted on the shaft 9 and interposed between the inner ring 5 of the sacrificial ball joint 3c and the body 2 of the connecting element 1. The clamping washer 11 is engaged inside a groove (not referenced) formed on the threaded shaft 9. According to one embodiment, the first main face A of the body 2 may comprise a nickel and / or cobalt alloy resistant to the high temperatures created by the combustion in the engine and the opposing second main face B of the body 2 may comprise a titanium and / or nickel alloy.

Claims

1. Connecting element (1), in particular for supporting an engine, comprising a body (2) and a first ball joint (3a) and a second ball joint (3b) which are mounted on the body (2), characterized in that it comprises a sacrificial third ball joint (3c) which is distinct from the first and second ball joints (3a, 3b) and is supported by the body (2), the sacrificial ball joint (3c) comprising an outer ring (4) and an inner ring (5) having a spherical inner surface (4a) and a spherical outer surface (5b), respectively, in contact with one another, the outer ring (4) projecting laterally on either side of the body (2), said connecting element (1) further comprising a device for fixing said sacrificial ball joint (3c) to said body (2).

2. Connecting element (1) according to Claim 1, wherein the outer surface (4b) of the outer ring (4) of the sacrificial ball joint (3c) comprises at least one planar face (6), and preferably two opposing planar faces (6).

3. Connecting element (1) according to either of Claims 1 and 2, wherein at least the outer surface (4b) of the outer ring (4) of the sacrificial ball joint (3c) comprises a bronze coating and / or cobalt alloy coating.

4. Connecting element (1) according to any one of Claims 1 to 3, wherein the body (2) of said connecting element (1) comprises an elongate portion (2a) in which the first and second distinct ball joints (3a, 3b) are located and a protruding portion (2b) projecting transversely with respect to the elongate portion (2a) and supporting the sacrificial ball joint (3c).

5. Connecting element (1) according to any one of Claims 1 to 4, wherein the fixing device comprises a threaded shaft (9), which extends through the inner ring (5) of the sacrificial ball joint (3c) and is inserted into a recess (10) in the body (2), and a clamping washer (11) mounted on the shaft (9) and interposed between the inner ring (5) of the sacrificial ball joint (3c) and the body (2).

6. Connecting element (1) according to any one of Claims 1 to 4, wherein the fixing device comprises a thread (7) formed on the body (2), or on a shaft (9) connected to the body (2), and on which the inner ring (5) of the sacrificial ball joint (3c) is fixed.

7. Connecting element (1) according to Claim 6, wherein the fixing device further comprises a groove (8) formed on the body (2) or on the shaft (9) in the extension of the thread (7) and inside which a protrusion of the inner ring (5) of the sacrificial ball joint (3c) is housed.5 8. Connecting element (1) according to Claim 6, wherein the fixingdevice further comprises a nut (12) for locking the sacrificial ball joint (3c), the nut being mounted on the body (2) or on the shaft (9).

9. Connecting element (1) according to any one of Claims 1 to 8, wherein the first and second ball joints (3a, 3b) comprise two parallel axes of rotation 10 (RI) and wherein the sacrificial ball joint (3c) comprises an axis of rotation (R2) orthogonal to said axes of rotation (RI).

10. Connecting element (1) according to any one of Claims 1 to 9, wherein a first main face (A) of the body (2) comprises a nickel and / or cobalt alloy and an opposing second main face (B) of the body (2) comprises a titanium and / or 15 nickel alloy.

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