AIRCRAFT CONNECTING ROD INCLUDING ANTI-LOOSENING MEANS

Abstract

Nested connecting rod (1) for aircraft turbomachine, comprising a bored body (2), a first screw (3) comprising a head (3c), a threaded rod (3b) having a thread oriented in a first direction (D1) and an internal tapping having a thread oriented in a second direction (D2), said tapping extending from the head of the first screw (3) along the rod, a second threaded screw (4) having a thread oriented in the second direction (D2) inserted in the first bored screw (3), the first screw (3) being configured to be screwed into the bored body (2), said bored body (2) comprising a tapping (2d) oriented in the first direction (D1) corresponding to the thread of said first screw (3).The nested connecting rod (1) is characterized in that it includes anti-loosening means via the opposing threads of the bored body (2) with the first screw (3) and of the first screw (3) with the second screw (4), and via at least one tightening tool for the first screw (3) on the body (2). Figure for the abbreviation: Fig 1.

Description

Title of the invention: AIRCRAFT CONNECTING ROD COMPRISING ANTI-LOOSENING MEANS Technical field

[0001] The invention has as its technical field the force transmission mechanisms for aircraft, intended to transmit a force between two components, and more particularly the connecting rods located in the turbomachines of aircraft.

[0002] For example, the two components are a linear actuator and a moving element.

[0003] Connecting rods often include an important clamping feature. Indeed, the connecting rods must be tightened correctly to guarantee the safety, durability, and efficiency of the aircraft's functions. An improperly tightened connecting rod can lead to misalignment, resulting in instability and premature wear of components. Furthermore, properly tightening the connecting rods maintains their desired length and ensures optimal power transmission between components, thus enabling the turbomachine to function correctly. Previous techniques

[0004] Commonly used connecting rods comprise two screws, each with at least two serrated washers mounted on either side of the screws, and at least two nuts mounted against the two serrated washers to tighten the serrated washers against the screws. The connecting rods also include a locking wire inserted through holes in the serrated washers to completely prevent the connecting rod from loosening. Inserting the locking wire into the holes in the serrated washers is a complex step.

[0005] In the event of maintenance and adjustment of the turbomachinery connecting rods, they are required to be loosened and tightened again.

[0006] Maintaining a connecting rod is often complex, particularly when the rod is difficult to access, which is frequently the case in turbomachinery. For example, the connecting rods for variable stator vanes, known as VSV rods (Variable Stator Vanes), are located inside the turbomachine's compressor and upstream of the rotor blades. Furthermore, maintaining these connecting rods is delicate because they are generally located in environments with extreme temperatures and are often small in size.

[0007] In this way, maintenance interventions are dangerous and involve complex and meticulous procedures often requiring partial or complete dismantling of the turbomachine compressor. Description of the invention

[0008] The present invention aims to overcome the aforementioned disadvantages and, in particular, to facilitate the maintenance of connecting rods in aircraft turbomachinery.

[0009] The invention therefore relates to a nested connecting rod for an aircraft turbomachine, comprising a bored body, a first screw comprising a head, a threaded rod having a thread oriented in a first direction and an internal tapping having a thread oriented in a second direction, said tapping extending from the head of the first screw along the rod, a second threaded screw having a thread oriented in the second direction inserted into the first bored screw, the first screw being configured to be screwed into the bored body, said bored body comprising a tapping oriented in the first direction corresponding to the thread of said first screw.The said nested connecting rod is characterized in that it includes anti-loosening means by means of the opposing threads of the bored body with the first screw and of the first screw with the second screw and by means of at least one tool for tightening the first screw on the body.

[0010] Advantageously, the connecting rod includes a counter-rotating lock nut mounted on the second screw with a thread oriented in the second direction against the first screw and which includes a locking element for the lock nut.

[0011] Optionally, the locking element includes an elastic ring and / or a locking wire disposed around the lock nut and the head of the first screw, and / or a notched lock nut anti-loosening plate positioned between the lock nut and the head of the first screw.

[0012] According to one embodiment, the clamping tool comprises at least one spring and a toothed washer positioned in the bored body, said toothed washer being interposed between said spring and the first screw and is configured to work in compression against a circular face of the first screw when the first screw loosens from the bored body.

[0013] Advantageously, the inner wall of said bored body includes at least one groove for retaining the toothed washer in which a lug of the toothed washer is housed.

[0014] According to one embodiment, the clamping tool comprises at least one spring and a toothed washer positioned in the first screw, said toothed washer being interposed between said spring and the second screw.

[0015] Advantageously, the inner wall of said first screw includes at least one groove for retaining the toothed washer in which a lug of the toothed washer is housed.

[0016] According to one embodiment, the clamping tool includes an elongated locknut comprising a tapping oriented in the second direction disposed around the body and the first screw and a locking element of the elongated locknut on said body and said first screw.

[0017] Advantageously, the locking element of the elongated locknut includes an anti-loosening plate disposed on the elongated locknut.

[0018] The invention also relates to an aircraft turbomachine comprising a connecting rod as defined above. Brief description of the drawings

[0019] Other objects, features and advantages of the invention will become apparent from the following description, given solely by way of non-limiting example and made with reference to the accompanying drawings in which:

[0020] - Figure [Fig. 1] schematically represents a nested connecting rod comprising anti-loosening devices;

[0021] - Figure [Fig.2] schematically represents a notched washer used in a tool for tightening a nested connecting rod;

[0022] - Figure [Fig.3] schematically represents a nested connecting rod comprising anti-loosening means in a different embodiment from [Fig.1];

[0023] - Figure [Fig.4A] represents a perspective view of a nested connecting rod including anti-loosening means in an embodiment different from Figures 1 and 3; and

[0024] - Figure [Fig. 4B] shows a side view of a nested connecting rod comprising anti-loosening means in an embodiment shown in [Fig.4A]. Detailed description

[0025] The invention aims to facilitate the maintenance of connecting rods in aircraft turbomachinery and, in particular, to allow for easier adjustment of the connecting rod while maintaining a high level of tightening. The connecting rod must be able to effectively withstand a specific force and not loosen under said force.

[0026] Figures 1, 3, 4A and 4B show a nested connecting rod 1 for an aircraft, and particularly a VSV connecting rod 1 located in a turbomachine of an aircraft. The connecting rod 1 comprises a bored body 2 and a first screw 3 comprising a head 3c and a threaded rod 3b having a thread oriented along a first direction DI and an internal tapping having a thread oriented along a second direction D2, said tapping extending from the head of the first screw 3 along the rod. The connecting rod 1 further comprises a second threaded screw 4 having a thread oriented along the second direction D2 and means for preventing loosening of said nested connecting rod 1.

[0027] The first screw 3 is configured to be screwed into the bored body 2, which includes an axial area of ​​its inner wall 2a that is tapped having a thread 2d oriented along the first direction DI corresponding to the thread of the first screw, and the second screw 4 is partially inserted into the thread of the first bored screw 3. Thus, the first end of the connecting rod 1 comprises the body 2, the second end comprises the second screw 4, and the center of the connecting rod 1 comprises the first screw 3.

[0028] The first direction DI here corresponds to a right-hand orientation of the thread, and the second direction D2 corresponds to a left-hand orientation of the thread.

[0029] The body 2 is cylindrical and includes a ball joint 2b at one end and a circular slice 2c at the opposite end. The first screw 3 includes a circular face 3a from which extends the shank 3b at the end inserted into the body 2 and the screw head 3c at the opposite end. The head 3c faces axially the circular slice 2c of the body 2. The second screw 4 includes a circular surface 4a at the end inserted into the first screw 3 and a ball joint 4b at the opposite end.

[0030] In the first embodiment illustrated in [Fig. 1], the connecting rod 1 is assembled so that there is a first gap 5 between the body 2 and the first screw 3 and a second gap 6 between the first screw 3 and the second screw 4. More particularly, a first gap 5 exists between the circular edge 2c of the body 2 and the head 3c of the first screw 3 and a second gap 6 exists between the bottom of the bore of the first screw 3 and the circular surface 4a of the second screw 4.

[0031] The first and second gaps 5, 6 are brought together, thus allowing the operations performed on said link 1 to be grouped in the center of the connecting rod 1. Adjusting the first screw 3 allows the first gap 5 between the body 2 and the first screw 3 to be managed, and adjusting the second screw 4 allows the second gap 6 between the first screw 3 and the second screw 4 to be managed.

[0032] The connecting rod 1 includes a lock nut 7 mounted counter-rotatingly on the second screw 4 with a left-hand thread D2 and against the head 3c of the first screw 3 and a locking element 8 for the lock nut 7. In the embodiment illustrated in [Fig. 1], the locking element 8 includes an elastic ring and / or a locking wire disposed around the lock nut 7 and said head 3c of the first screw 3. The counter-rotating lock nut 7 therefore has a counter-clockwise tightening direction.

[0033] The connecting rod 1 operates on the principle of nested screws with opposing threads. Specifically, the assembly comprising the bored body 2 and the first screw 3 has a right-hand thread DI, and the assembly comprising the first screw 3 and the second screw 4 has a left-hand thread D2. The opposing threads between the assembly including the bored body 2 and the first screw 3 and the assembly including the first screw 3 and the second screw 4 are part of the anti-loosening means of the nested connecting rod 1. Indeed, the principle of antagonistic threads makes it possible to reduce the play and reaction forces which can appear within the connecting rod when it tends to loosen.

[0034] The means for preventing loosening of the connecting rod 1 also include a tool for tightening its components, and particularly the first screw 3 on the body 2. The tightening tool comprises a spring 9a and a toothed washer 10a positioned in the bored body 2. The spring 9a is located at the bottom of the bore of the body 2, and the toothed washer 10a is interposed between said spring 9a and the first screw 3. The toothed washer 10a is configured to work in compression against the first screw 3, in particular against the circular face 3a of the first screw 3, when said first screw 3 loosens from the bored body 2.

[0035] Fig. 2 schematically illustrates, from the front, the toothed washer 10a arranged between the spring 9a and the first screw 3, and particularly between the spring 9a and the circular face 3a of the first screw 3. The toothed washer 10a is a circular washer comprising in its center a through hole 11, into which the shank 3b of the first screw 3 is inserted. The circular face 3a of the first screw 3 comprises notches complementary to the notches of the toothed washer 10a.

[0036] As illustrated in [Fig. 1], the inner wall 2a of the bored body 2 includes two axial grooves 12a for retaining the toothed washer 10a. More specifically, the body 2 includes two axial grooves 12a which extend along the thread of the body 2. The toothed washer 10a has two lugs 13 housed respectively in the grooves 12a of the body.

[0037] The anti-loosening of the connecting rod 1 in the first embodiment illustrated in [Fig.1] is also achieved by the friction caused by the contact between the serrated washer 10a and the circular face 3a of the first screw 3 as well as by the locking of the lock nut 7 and the locking element 8 of the lock nut 7.

[0038] The advantage of the anti-loosening means of the first embodiment is to limit the number of loose parts when adjusting the connecting rod 1. Indeed, the clamping tool integrated inside the body 2 of the connecting rod 1 does not require any manipulation by the operator.

[0039] In the second embodiment illustrated in [Fig. 3], the connecting rod 1 also includes a first gap 5 between the circular edge 2c of the body 2 and the head 3c of the first screw 3, and a second gap 6 between the bottom of the bore of the first screw 3 and the circular surface 4a of the second screw 4. Adjusting the first screw 3 allows for the management of the first gap 5 between the body 2 and the first screw. 3 and adjusting the second screw 4 allows you to manage the second gap 6 between the first screw 3 and the second screw 4.

[0040] The connecting rod 1 includes two tools for tightening its components and particularly a tool for tightening the first screw 3 on the body 2 and a tool for tightening the second screw 4 on the first screw 3. The tool for tightening the first screw 3 on the body 2 is similar to the tightening tool shown in the embodiment illustrated in [Fig.1].

[0041] In this embodiment, the second screw 4 comprises a rod 4c extending from its circular surface 4a.

[0042] The tool for tightening the second screw 4 on the first screw 3 comprises a spring 9b and a toothed washer 10b positioned in the bore of the first screw 3. The spring 9b is located at the bottom of the bore of the first screw 3, and the toothed washer 10b is interposed between said spring 9b and the circular surface 4a of the second screw 4.

[0043] The toothed washer 10b of the second clamping tool is smaller than the toothed washer 10a of the first clamping tool. The toothed washer 10b is a circular washer having a through hole 11 in its center, into which the shank 4c of the second screw 4 is inserted. The circular surface 4a of the second screw 4 has notches that are complementary to the notches of the toothed washer 10b.

[0044] As illustrated in [Fig. 3], the inner wall of the first bored screw 3 comprises two axial grooves 12b for retaining the toothed washer 10b. More specifically, the first screw 3 comprises two grooves 12b which extend along the thread of the first screw 3 to the end of the head 3c of the first screw 3. The toothed washer 10b has two lugs 13 housed respectively in the grooves 12b of the first screw 3.

[0045] In this embodiment, the anti-loosening of the connecting rod 1 is achieved by the friction caused by the contact between the toothed washer 10a and the notched circular face 3a of the first screw 3 and by the friction caused by the contact between the toothed washer 10b and the circular surface 4a of the second screw 4.

[0046] The advantage of the anti-loosening means in the second embodiment is that they completely eliminate the need to tighten the connecting rod 1. Indeed, the tightening tools integrated inside the body 2 and inside the first screw 3 of the connecting rod 1 do not require any manipulation by the operator. Due to the complexity of this embodiment, the second embodiment illustrated in [Fig. 3] is primarily used for testing and development on turbomachinery, particularly for testing the length of the connecting rods. The architecture of the connecting rod 1 in this embodiment results in a higher cost.

[0047] In the third embodiment illustrated in Figures 4A and 4B, the connecting rod 1 includes a first gap 5 between the circular slice 2c of the body 2 and the head 3c of the first screw 3 and a second gap 6 between the bottom of the bore of the first screw 3 and the circular surface 4a of the second screw 4. The connecting rod 1 includes a lock nut 7 mounted counter-rotatingly on the second screw 4 with a left-hand thread D2 and a locking element 8 of said lock nut 7 and a tool for tightening its components and particularly a tool for tightening the first screw 3 on the body 2.

[0048] The tightening tool includes an elongated lock nut 14 having a left-hand thread D2 disposed around the body 2 and the first screw 3 and a locking element 15 of the elongated lock nut 14 on said body 2 and said first screw 3. The elongated lock nut 14 is counter-rotating, that is to say, it has a counter-clockwise tightening direction.

[0049] The locking element 15 of the elongated locknut 14 includes an anti-loosening plate disposed on the elongated locknut 14, and the locking element 8 of the locknut 7 includes an anti-loosening plate. The anti-loosening plate of the locknut 7 is serrated and positioned between the locknut 7 and the head 3c of the first screw 3.

[0050] The locknuts 7, 14 provide adequate tightening to the connecting rod 1. The operations are carried out on the first screw 3 allowing modification of the length of the connecting rod 1.

[0051] This architecture also makes it possible to limit the number of loose parts when adjusting the connecting rod 1. The embodiment illustrated in figures 4A and 4B is applied during the manufacture of turbomachinery in series, in particular integrated into aircraft.

[0052] Of course, we do not depart from the scope of the invention when the connecting rod 1 has a different composition not shown in the figures. It is thus possible to design a nested connecting rod 1 comprising the clamping tool described in the first embodiment and the clamping tool described in the third embodiment, or a nested connecting rod 1 as described in the second embodiment, further comprising a lock nut 7 and a locking element for the lock nut 8.

Claims

Demands

1. Nested connecting rod (1) for aircraft turbomachinery, comprising a bored body (2), a first screw (3) comprising a head (3c), a threaded rod (3b) having a thread oriented in a first direction (Dl) and an internal tapping having a thread oriented in a second direction (D2), said tapping extending from the head of the first screw (3) along the rod, a second threaded screw (4) having a thread oriented in the second direction (D2) inserted into the first bored screw (3), the first screw (3) being configured to be screwed into the bored body (2), said bored body (2) comprising a tapping (2d) oriented in the first direction (Dl) corresponding to the thread of said first screw (3),said nested connecting rod (1) being characterized in that it comprises anti-loosening means by means of the opposing threads of the bored body (2) with the first screw (3) and of the first screw (3) with the second screw (4) and by means of at least one tightening tool of the first screw (3) on the body (2) comprising at least one spring (9b) and one toothed washer (10b) positioned in the first screw (3), said toothed washer (10b) being interposed between said spring (9b) and the second screw (4).

2. Link (1) according to claim 1, which includes a lock nut (7) mounted counter-rotatingly on the second screw (4) with a thread oriented along the second direction (D2) against the first screw (3) and which includes a locking element (8) for the lock nut (7).

3. Link (1) according to claim 2, wherein the locking element (8) comprises an elastic ring and / or a locking wire disposed around the lock nut (7) and the head (3c) of the first screw (3), and / or a notched lock nut (7) anti-loosening plate positioned between the lock nut (7) and the head (3c) of the first screw (3).

4. Link (1) according to any one of claims 1 to 3, wherein the clamping tool comprises at least one spring (9a) and one toothed washer (10a) positioned in the bored body (2), said toothed washer (10a) being interposed between said spring (9a) and the first screw (3) and is configured to work in compression against a circular face (3a) of the first screw (3) when the first screw (3) loosens from the bored body (2).

5. Connecting rod (1) according to claim 4, wherein the inner wall (2a) of said bored body (2) comprises at least one groove (12a) for retaining the toothed washer (10a) in which is housed a lug (13) of the toothed washer (10a).

6. Link (1) according to any one of claims 1 to 5, wherein the inner wall of said first screw (3) includes at least one groove (12b) for retaining the toothed washer (10b) in which is housed a lug (13) of the toothed washer (10b).

7. Link (1) according to any one of claims 1 to 6, wherein the clamping tool comprises an elongated locknut (14) comprising a thread oriented along the second direction (D2) disposed around the body (2) and the first screw (3) and a locking element (15) of the elongated locknut (14) on said body (2) and said first screw (3).

8. Link (1) according to claim 7, wherein the locking element (15) of the elongated locknut (14) comprises an anti-loosening plate disposed on the elongated locknut (14).

9. Aircraft turbomachine comprising a connecting rod (1) according to any one of claims 1 to 8.