BALL JOINT SYSTEM FOR ACTUATING A MOVING PART OF AN AIRCRAFT TURBOMACHINE
The ball joint system addresses wear and hyperstaticity issues by clamping the joint at its ends, reducing shaft wear and maintaining functional integrity.
Patent Information
- Authority / Receiving Office
- FR · FR
- Patent Type
- Patents
- Current Assignee / Owner
- Filing Date
- 2023-03-22
- Publication Date
- 2026-03-13
AI Technical Summary
Existing ball joint systems in aircraft turbomachines experience wear and hyperstaticity issues due to intentional operating clearances and tight retention, leading to premature wear and functional indeterminacy.
A ball joint connection system where the ball joint is clamped at its ends along the axis, preventing translation while allowing the shaft to translate, with an operating clearance to prevent static indeterminacy.
Reduces shaft wear and maintains functional integrity by preventing unnecessary stress, enhancing the service life of ball joint components.
Smart Images
Figure 00000011_0000 
Figure 00000011_0001 
Figure 00000012_0000
Abstract
Description
Title of the invention: BALL JOINT LINKAGE SYSTEM FOR ACTUATING A MOVING PART OF AN AIRCRAFT TURBO MACHINE technical field
[0001] The invention relates to the field of kinematics of moving parts of an aircraft turbomachine. It relates in particular to a ball joint system for actuation of a moving part of an aircraft turbomachine. Previous technique
[0002] In an aircraft turbomachine, to regulate the flow rate of the air circulating in a duct and to avoid the pumping phenomenon or to evacuate debris present in said duct, it is known to use variable discharge valves.
[0003] Such valves can be in the closed position and not cause any change in the circulation of the air flow at the level of the vein in which they are mounted or in the open position in which all or part of the flow is diverted to another vein by passing through the opening.
[0004] Fig. 1, from patent application WO-A1-2020 / 007847, shows an aircraft turbomachine 100 extending longitudinally along an X axis.
[0005] The turbomachine 100 comprises a fan 104, an inner shell 105, and an outer shell 106. The fan 102 is driven in rotation about the X-axis of the turbomachine 100 in order to draw in an airflow which is separated by the inner shell 105 into a first drive airflow for the turbomachine, called the primary flow, and a second thrust airflow, called the secondary flow. The inner shell 105 extends substantially along the X-axis of the turbomachine 100, and the outer shell 106 extends outside the inner shell 105.
[0006] The primary airflow extends internally to the inner ferrule 105 in a primary vein VI while the secondary airflow extends externally to the inner ferrule 105 in a secondary vein V2. The inner ferrule 105 and the outer ferrule 106 delimit the secondary vein V2 for the circulation of the secondary airflow.
[0007] The turbomachine 100 includes a compressor 101 to accelerate the primary flow, a combustion chamber 102 to energize it and a turbine 103 driven by the energized airflow to drive the compressor 101.
[0008] Typically, in an aircraft turbomachine of this type, the compressor 101 includes variable relief valves that are configured to move between a closed position, in which circulation of airflow from the primary flow VI to the secondary flow V2 is prohibited, and an open position in which a circulation of air from the primary flow VI to the secondary flow V2 is prohibited. The culation of the air flow from the primary vein VI to the secondary vein V2 is permitted.
[0009] Fig. 2 (from patent FR-B1-2982904) and Fig. 3 show, in an embodiment according to the prior art, the various parts which enable the movement (also referred to as kinematics), around an axis 201, of the variable discharge valves and which can be, for example, integrated into a compressor.
[0010] In this example, a control ring 203 is driven in rotation by hydraulic cylinders 205 and is connected to a gate 207 for each variable discharge valve 209 by complex articulation devices called a guignol (shown in more detail in [Fig.3]).
[0011] Fig. 3 shows the force transmission chain, going from a cylinder 205 to a gate 207 of a variable relief valve 209, which allows the movement of this variable relief valve 209 and, in particular, the passage from an open position to a closed position by a rotation around the axis 201 (visible in Fig. 2).
[0012] In this example, the force is transmitted from the connecting rod 205b of the cylinder 205 to a first puppet 301, called the master puppet. This drives the opening (or closing) of the door 207 (located on the right in the figure) via a connecting rod 303 (the door 207 being articulated by a hinge 305).
[0013] The force is then transmitted from the master lever 301 to the control ring 203 (to which all the variable discharge valves 209 are connected) and then from the control ring 203 to a second lever 307, called the slave lever. The slave lever 307 in turn opens or closes the gate 207 of a variable discharge valve 209 (located on the left in [Fig. 3]) via a connecting rod 309.
[0014] In addition, the seal 311 and the seal holder 313 on the one hand, and the pad 315 on the other hand, respectively ensure proper sealing of the assembly when the valves are in the closed position and optimal movement of the control ring 203 when the assembly is set in motion.
[0015] In this force transmission chain shown in [Fig. 3], all the circles surrounding a mechanical linkage, in particular, enclose ball joints between different parts of the chain. Thus, numerous ball joints are present in this force transmission chain used to actuate variable relief valves.
[0016] Figures 4 to 6 illustrate in more detail three examples of ball joints of the force transmission chain described above.
[0017] In particular, [Fig. 4] represents a ball joint system 401 between a control arm 403 and a connecting rod 405, [Fig. 5] represents a ball joint system 501 between a control ring 503 and a control arm 505, and [Fig. 6] represents a ball joint system 601 between a gate 603 of a variable relief valve and a connecting rod 605.
[0018] All these ball joint linkage systems include a shaft 407 inserted into through holes in one of the two parts (punch, control ring or door) and held in these holes by means of fixing means 409 (of the shaft in the part in question) and bushings 411, positioned in these holes.
[0019] All ball joint systems also include a ball joint 413 which is integral with the other part (linkage, guignol or connecting rod), which surrounds the axis 407 at the level of an opening in the first part and which thus allows the rotation of the second part around the axis 407.
[0020] In the first two ball joint systems 401 and 501 described, where the axis 407 is respectively a screwed and wire-locked chamfered axis and an offset fixed axis, an operating clearance remains (intentionally) in the assembled system between the ball joint 413 and the bushings 411 surrounding it so that the ball joint 413 is free to translate on the axis 407.
[0021] In the third ball joint system 601 described, where the shaft 407 is a smooth-shank screw that is tightened by a nut, the ball joint 413 is clamped between the two bushings 411 and no operating play is present in the shaft / bushings / ball joint assembly, so that no translation along the direction of the shaft is possible.
[0022] In the first case (systems 401 and 501), the movement of the ball joint on the shaft causes wear on the shaft. By way of example, [Fig. 7] shows a shaft 701 (with offset mounting) after its use in a ball joint system according to the prior art. The shaft 701 clearly exhibits a corrosion zone 703 and a wear zone 705, which are the result of the ball joint's movements around the shaft 701.
[0023] In the second case (system 601), the tight retention of the ball joint and the absence of operating play in the shaft / bushings / ball joint assembly leads to hyperstaticity of the assembly, i.e. that at least one degree of mobility of the part concerned is eliminated several times (i.e. more times than necessary). Summary of the invention
[0024] The present invention proposes a solution to these drawbacks.
[0025] Thus, one objective of the invention is to reduce the sources of wear on parts of a ball joint system used for actuation of a variable relief valve.
[0026] To this end, the invention, according to a first aspect, relates to a ball joint connection system for actuation of a moving part of an aircraft turbomachine, said system comprising:
[0027] - a first part comprising an opening and through holes positioned opposite, on either side of the said opening;
[0028] - an axis inserted into the orifices and held in said orifices by means of of fastening means and sockets, positioned in said orifices, between said axis and said first part;
[0029] - a second piece; and,
[0030] - a ball joint, integral with the second part, and surrounding the axis at the opening of the first part, so as to allow the rotation of the second part around said axis,
[0031] said system being characterized in that the axis, the fixing means and the sockets are configured so that, when said system is assembled, the ball joint is clamped at its ends in the direction of the axis so that the translation of said ball joint along said axis is prevented and a clearance allows the axis to translate in its direction.
[0032] The system according to the invention may comprise one or more of the following features, taken individually or in combination with each other:
[0033] - the moving part is a variable relief valve, the first part is a ring variable discharge valve control and the second part is a puppet.
[0034] - the moving part is a variable discharge valve, the first part is a gate of a variable discharge valve and the second part is a connecting rod.
[0035] - the moving part is a variable relief valve, the first part is a puppet and the second part is a connecting rod.
[0036] - when said system is assembled, two faces of the ball joint, located at the ends of said ball joint along the direction of the axis, are supported on two faces of the sockets so that the ball joint is clamped at said ends.
[0037] - the fastening means include a screw head and a thread integrated into the shaft, and a complementary threaded nut for said thread. - the threaded nut is of the floating nut or barrel nut type.
[0038] - the sockets comprise a captive sliding socket positioned in a first orifice of the first part and a sleeve fitted into a second orifice of the first part.
[0039] - the axis is a screw with a smooth shank and the fixing means correspond to a head of said screw and a complementary nut for said screw.
[0040] The invention according to a second aspect also relates to a turbomachine comprising a control ring, a plurality of variable discharge valves and at least one system according to the first aspect. Brief description of the drawings
[0041] The invention will be better understood with the aid of the following description, given solely by way of example and made with reference to the accompanying drawings in which:
[0042] [Fig.1] is a schematic representation of an embodiment of a tur-bomachine according to the prior art;
[0043] [Fig.2] is a schematic representation of an embodiment of an assembly comprising a control ring and variable discharge valves according to the prior art;
[0044] [Fig.3] is a perspective view of an embodiment of a control ring and variable discharge valves according to the prior art;
[0045] [Fig.4] is a cross-sectional view of an embodiment of a ball joint system according to the prior art;
[0046] [Fig.5] is a cross-sectional view of an embodiment of a ball joint system according to the prior art;
[0047] [Fig.6] is a cross-sectional view of an embodiment of a ball joint system according to the prior art;
[0048] [Fig.7] is an illustration of the wear of an axle used in a ball joint system according to the prior art;
[0049] [Fig. 8] is a cross-sectional view of an embodiment of a ball joint system according to the invention; and,
[0050] [Fig.9] is a cross-sectional view of an embodiment of a ball joint system according to the invention. Description of the implementation methods
[0051] With reference to [Fig.8], we will now describe an embodiment of a ball joint system 801 for actuation of a moving part of an aircraft turbomachine according to the invention.
[0052] In all that follows, the moving part is a variable relief valve. However, those skilled in the art will appreciate that the invention applies to any moving part (relative to an aircraft reference frame) of an aircraft turbomachine required to perform a movement related to said ball joint.
[0053] The system 801 described with reference to [Fig.8] is a ball joint linkage system between a first part 803 which is a puppet and a second part 805 which is a connecting rod.
[0054] However, those skilled in the art will appreciate that the invention applies more generally to all ball joints which are involved in the kinematics (i.e. which contribute to their movement) of variable discharge valves.
[0055] In particular, the invention applies to all ball joint linkage systems that are present in the force transmission chain involving (in order) the following parts: a cylinder, a connecting rod, a master control arm, a control ring, a slave control arm, a connecting rod and finally a gate of a variable relief valve and which lead to the activation of the variable discharge valve.
[0056] The system 801 described below can, for example, be included in an aircraft tur-bomachine which also includes a control ring such as the control ring 203 described with reference to [Fig.2] and a plurality of variable relief valves such as the variable relief valves 209 described with reference to [Fig.2] also or to [Fig.3]. Such a system is intended to be fitted in an aircraft turbomachine (such as the turbomachine 100 described with reference to [Fig.1]), for example in a compressor or between a low-pressure compressor and a high-pressure compressor.
[0057] In the non-limiting example shown in [Fig.8], the puppet 803 has an opening 807 and through holes 809 positioned opposite each other, on either side of the opening 807. In this case, two portions 803a and 803b of the puppet 803 extend parallel to each other and form the sides of a U in which two holes 809 are drilled aligned opposite each other and between which the opening 807 is located.
[0058] An axle 811 is inserted into the orifices 809 and held in said orifices 809 by means of, on the one hand, fastening means 813 and, on the other hand, bushings 815, positioned in the orifices 809, between the axle 811 and the guignol 803.
[0059] In this case, in the non-limiting example shown, the shaft 811 is a screw with a smooth shank (which includes, for example, a sliding fit of type H7g6) and the fastening means 813 include a screw head 813a and a thread 813b which are integrated into the screw 811, and a threaded nut 813c (complementary to the thread 813b of the screw 811) which is a separate part.
[0060] Generally, in various embodiments, the fastening means may be integrated into the shaft or separate from it. In all cases, these fastening means 813 contribute to maintaining the shaft 811 in the holes 809 when the system 801 is assembled (and potentially subjected to significant vibrations). In particular, these fastening means 813 prevent the shaft 811 from exiting the holes 809 by translation along its direction (i.e., the direction of the longitudinal extent of the shaft 811).
[0061] In addition, the bushings 815 also contribute to holding the shaft 811 in the holes 809 insofar as the shape of the bushings is designed so that the shaft 811 is clamped in the holes 809 by means of the bushings 815 when the system 801 is assembled.
[0062] In particular, in the embodiment shown in [Fig. 8], the system comprises a first sleeve 815a which is a sliding sleeve, i.e., capable of translating (along its longitudinal extent) within the orifice 809 (in the upper part of the figure) in which it is positioned. Furthermore, it is a so-called sleeve impossible to lose since it has a clip 817 (which can also be a ring) which prevents the socket 815a from coming out of the orifice 809 once it is positioned in the orifice (in addition to a shoulder which forms the head of the socket).
[0063] In addition, the system 801 includes a second sleeve 815b which is press-fitted into the other orifice 809 (in the lower part of the figure). Unlike the first sleeve 815a, the second sleeve 815b therefore cannot move once positioned in the orifice 809.
[0064] The ball joint system 801 also includes a ball joint 819, integral with the connecting rod 805, and surrounding the axis 811 at the opening 807, so as to allow the connecting rod 805 to rotate around the axis 811.
[0065] As a reminder, in the case of a ball joint, the ball joint 819 allows not only rotation around the axis 811 but also rotations (or combinations of these rotations) around all the axes of an orthonormal frame of reference, one of whose axes coincides with the longitudinal direction of the axis 811. The ball joint is therefore made between the puppet 803 and the connecting rod 805 via the axis 811 and the ball joint 819.
[0066] A first specific feature of the invention lies in the fact that the shaft 811, the fastening means 813, and the bushings 815 are configured so that, when the system 801 is assembled, the ball joint 819 is clamped at its ends along the direction of the shaft 811, thus preventing the translation of the ball joint 819 along the shaft 811. In other words, the shape and dimensions of these parts are designed so that, once the system 801 is assembled, the translation of the ball joint 819 along the shaft 811 (i.e., its sliding) is blocked.
[0067] In the non-limiting example shown, when the system 801 is assembled, two (flat) faces of the ball joint 819 which are located at its ends along the direction of the axis 811, are in contact with two (also flat) faces of the bushings 815 so that the ball joint 819 is clamped at its ends and therefore cannot translate along this direction on the axis 811.
[0068] A second specific feature of the invention lies in the fact that, once the system 801 is assembled, a clearance (operating clearance) 821 allows the shaft 811 to translate along its direction. In other words, the ball joint 819 cannot translate along the shaft 811, but the shaft 811 itself can translate within the openings 809 of the control arm 803 along its longitudinal extension direction. In the non-limiting example shown, the clearance 821 is located between the head of the bushing 815a and the edge of the opening 809 into which it is inserted.
[0069] Figure 9 shows another embodiment of the invention in which the first part 803 is a control ring for variable relief valves and the second part 805 is a control arm. In this example, the opening 807 is located in the middle of the thickness of the control ring 803.
[0070] Furthermore, in the embodiment shown in [Fig. 8], the threaded nut 813c is a The nut is floating, whereas in the embodiment shown in [Fig. 9], the threaded nut is a barrel nut. The latter has the advantage of being captive and of not causing any protrusion at the control ring.
[0071] In addition to the examples shown in Figures 8 and 9, as mentioned above, the invention applies to all ball joints present in the force transmission chain which enables the movement of one or more relief valves.
[0072] For example, in another embodiment not shown, the first part may be a gate of a variable discharge valve and the second part a connecting rod.
[0073] In all cases, the ball joint 819 is clamped on the axis 811 and therefore cannot slide along the axis 811 while the operating clearance 821 allows the axis 811 to slide, according to its direction, in the orifices 809 (in addition to its rotational movement on itself).
[0074] In all cases (i.e., for all embodiments), the fact that the ball joint is clamped onto the shaft reduces shaft wear caused by friction between the ball joint and the shaft. Furthermore, maintaining the shaft's ability to translate along its direction also reduces wear by potentially using a larger shaft (depending on its longitudinal length, in particular) and by also using bushings. Thus, the shafts used can be more robust and protected by bushings (used as wear parts), resulting in a longer service life. Finally, the operating clearance present in the assembled system prevents the system from becoming statically indeterminate, that is, it avoids adding stresses that are not necessary for the proper functioning of the ball joint.
Claims
Demands
1. Ball joint system (801) for actuation of a moving part of an aircraft turbomachine, said system (801) comprising: - a first part (803) having an opening (807) and through holes (809) positioned opposite each other on either side of said opening (807); - a shaft (811) inserted into the holes (809) and held in said holes (809) by means of fastening means (813) and bushings (815), positioned in said holes (809), between said shaft (811) and said first part (803); - a second part (805);and, - a ball joint (819), integral with the second part (805), and surrounding the axis (811) at the level of the opening (807) of the first part (803), so as to allow the rotation of the second part (805) around said axis (811), said system (801) being characterized in that the axis (811), the fastening means (813) and the bushings (815) are configured so that, when said system (801) is assembled, the ball joint (819) is clamped at its ends along the direction of the axis (811) so that the translation of said ball joint (819) along said axis (811) is prevented and a clearance (821) allows the axis (811) to translate along its direction.;
2. System (801) according to claim 1, wherein the moving part is a variable relief valve, the first part (803) is a variable relief valve control ring and the second part (805) is a puppet.
3. System (801) according to claim 1, wherein the moving part is a variable relief valve, the first part (803) is a gate of a variable relief valve and the second part (805) is a connecting rod.
4. System (801) according to claim 1, wherein the moving part is a variable relief valve, the first part (803) is a control horn and the second part (805) is a connecting rod.
5. System (801) according to any one of the preceding claims, wherein, when said system (801) is assembled, two faces of the ball joint (819), located at the ends of said ball joint (819) along the direction of the axis (811), are in contact with two faces of the bushings (815) so that the ball joint (819) is clamped at said ends.
6. System (801) according to any one of the preceding claims, wherein the fastening means (813) comprise a screw head (813a) and a thread (813b) integrated into the shaft (811), and a threaded nut (813c) complementary to said thread (813b).
7. System (801) according to claim 6, wherein the threaded nut (813c) is of the floating nut or barrel nut type.
8. System (801) according to any one of the preceding claims, wherein the bushings (815) comprise a captive sliding bushing (815a) positioned in a first orifice (809) of the first part (803) and a bushing (815b) shrunk in a second orifice (809) of the first part (803).
9. System (801) according to any one of the preceding claims, wherein the shaft (811) is a screw with a smooth shank and the fastening means (813) correspond to a head of said screw and a nut complementary to said screw.
10. Turbomachine comprising a control ring, a plurality of variable discharge valves and at least one system (801) according to any one of claims 1 to 9.