TOOLING FOR RETAINING A BLADE DURING FRICTION WELDING THEREOF TO A ROTOR ELEMENT OF AN AIRCRAFT TURBOMACHINE

Abstract

A tooling holds a blade during friction welding to a rotor element. The tooling includes a fixed jaw having a central part; two arms separated by a distance d for receiving at least one portion of the blade; and a fixed jaw body with bearing surfaces and a bore for receiving at least one portion of the blade. The bearing surfaces are configured to come into contact with the blade. A movable jaw includes a movable bearing surface that comes into contact with the blade, and pressure means that moves the movable jaw towards the fixed jaw body to press the blade.

Claims

1. A tooling for holding a blade during friction welding thereof to a rotor element of an aircraft turbomachine, comprising: a fixed jaw comprising: a central part adapted to be attached to a vibrating plate of a friction welding machine; two arms substantially parallel to each other, separated by a distance d for receiving at least a portion of the blade and substantially perpendicular to said central part; and a fixed jaw body disposed between the two arms, comprising bearing surfaces and a bore for receiving at least a portion of the blade, the bearing surfaces being intended to come into contact with faces of the blade; a movable jaw configured to slide along the two arms and comprising a movable bearing surface configured to contact a face of the blade; and pressure means configured to move said movable jaw towards the fixed jaw body to press the blade between the movable jaw and the fixed jaw body.

2. The tooling according to claim 1, wherein each of the two arms of the fixed jaw comprises a groove.

3. The tooling according to claim 2, wherein the movable jaw comprises two lateral edges capable of sliding in the grooves of the arms.

4. The tooling according to claim 3, wherein the movable jaw comprises a reinforcement portion perpendicular to said two lateral edges.

5. The tooling according to claim 4, wherein the movable bearing surface, the lateral edges and the reinforcement portion define an open area configured to receive, during the welding of said blade, another adjacent blade already welded.

6. The tooling according to claim 5, wherein the pressure means configured to be controlled by a control unit.

7. The tooling according to claim 6, wherein the pressure means comprise one or more cylinders.

8. The tooling according to claim 7, wherein each cylinder comprises a piston mechanically coupled to said movable jaw.

9. The tooling according to claim 8, wherein each arm of the fixed jaw is configured to accommodate one or two cylinders, so that the transmission of the force provided by said cylinder or cylinders is parallel to said arms.

10. The tooling according to claim 1, wherein the movable bearing surface of the movable jaw has a knurling.

11. The tooling according to claim 1, wherein the tooling is configured to hold a blade during its orbital friction welding.

12. The tooling according to claim 1, wherein the rotor element is a drum of a low-pressure compressor of a turbomachine of an aircraft.

13. An assembly for a friction welding process, comprising: a tooling according to claim 1; pins; and a vibrating plate configured to impart a vibratory motion to said tooling, the tooling being attached to the vibrating plate by means of said pins.

14. A method of friction welding a blade to a rotor element of an aircraft turbomachine, comprising the following steps: a. providing a tooling according to claim 1; b. providing a friction welding machine comprising a vibrating plate; c. attaching the central part of the tooling to said vibrating plate; d. arranging a portion of said blade to be welded in the bore of the fixed jaw body, so that the bearing surfaces come into contact with said blade; e. bringing into contact the movable bearing surface of the movable jaw with said blade; f. pressing said blade between the movable jaw and the fixed jaw body by means of the pressure means; g. bringing into contact said blade and said rotor element; h. actuating the friction welding machine so as to induce a relative movement between said blade and the rotor element to reach a welding temperature; i. stopping the vibrating plate and pressing said blade against said rotor element so as to join them together; and j. releasing said blade from the tooling.

15. The method according to claim 14, wherein the relative movement between said blade and the rotor element is an orbital movement.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0059] Further features and advantages of the invention will become apparent from the following detailed description, for the understanding of which reference is made to the appended figures, among which:

[0060] FIG. 1 shows the tooling according to one embodiment of the invention,

[0061] FIG. 2 shows the tooling in the presence of the blades to be welded, according to an embodiment of the invention,

[0062] FIG. 3 shows the tooling, the vibrating plate and a drum according to an embodiment of the invention,

[0063] FIG. 4 shows a portion of a drum on which a blade is welded according to an embodiment of the invention.

DETAILED DESCRIPTION OF SOME EMBODIMENTS OF THE INVENTION

[0064] The present invention is described with particular embodiments and references to figures, but the invention is not limited thereby. The drawings or figures described are only schematic and are not limiting. In the context of this document, the terms “first” and “second” are used only to differentiate between the various elements and do not imply any order between these elements. The reference signs do not limit the scope of the invention, but when included in the claims. In the figures, identical or similar elements may bear the same references.

[0065] FIG. 1 shows tooling 1 according to one embodiment of the invention. It comprises a fixed jaw 30 comprising a central part 31, two arms 32 substantially parallel to each other and a fixed jaw body 40.

[0066] The central part 31 and the arms 32 are arranged together to form a “U” shape in a cross-sectional view of the fixed jaw. In a preferred embodiment, the distance d between the arms 32 is smaller than the length of said arms 32, giving an elongated appearance to the tooling 1. Typically, the length of the arms 32 is at least twice of d. The central part 31 of the fixed jaw may be discontinuous.

[0067] The fixed jaw body 40 occupies a space between the two arms 32 that is approximately half the length of said arms 32. The fixed jaw body 40 is coupled to the arms 32 at its lateral sides and, possibly, coupled to the central part 31 at its lower portion. The fixed jaw body 40 is preferably arranged obliquely with respect to the arm 32. The fixed jaw body 40 has a bore 42. This bore 42 corresponds to a recess in the depth of the fixed jaw body 40. The entrance to this recess is preferably machined in such a way as to define bearing surfaces 41. During the welding operation of a blade 10 on a rotor element 20, the bore 42 is provided to receive, preferably entirely, the functional part 13 of the blade 10. The shape of the bore 42 preferably mimics the shape of the functional part 13 of the blade 10 so as to minimise the size of the recess while ensuring non-contact containment of the functional part 13 of the blade 10. The entrance to the bore 42 is preferably machined to define bearing surfaces 41 intended for coming into contact with a part of the blade 10 known as the platform 12. Preferably, there are three planar bearing surfaces 41 intended for coming into contact with three lateral faces 14 of a parallelepiped platform 12 of the blade 10. Even more preferably, the platform 12 is a rectangular parallelepiped. Thus, in this preferred embodiment, the bearing surfaces 41 are in contact with part of the perimeter of the platform 12 of the blade 10. Furthermore, the plane of each bearing surface 41 is preferably perpendicular to the plane of linear or, preferably, orbital motion of the friction weld in such case.

[0068] Preferably, the movable jaw 50 is arranged to translate only along the arms 32. In a preferred embodiment, the arms 32 comprise grooves 33 parallel to said arms 32. These grooves 33 are preferably provided to receive lateral edges 52 of the movable jaw 50 to improve the sliding. The movable jaw 50 comprises a movable bearing surface 51, preferably parallel to the fixed jaw body 40 and thus oblique with respect to the arms 32 when the fixed jaw body 40 is itself oblique with respect to the arms 32. Preferably, the movable bearing surface 51 remains parallel to the fixed jaw body 40 when the movable jaw 50 slides. When the blade 10 is positioned in the fixed jaw body 40 (the functional part 13 in the bore 42 and the platform in contact with the bearing surfaces 41 according to a preferred embodiment), the movable jaw 50 is arranged to move towards the fixed jaw body 40 so that the movable bearing surface 51 come into contact with a face 14 of the platform 12 of the blade 10. Preferably, the entire perimeter of the platform 12 is in contact with either the bearing surface 41 or the movable bearing surface 51. More preferably, three flat bearing surfaces 41 are intended to come into contact with three lateral faces 14 of a parallelepipedic platform 12, then the movable bearing surface 51, which is flat, is intended to come into contact with the fourth face 14 of the platform 12. Preferably, the movable bearing surface 51 is perpendicular to the plane of the linear or orbital movement of the friction welding. Optionally, the movable bearing surface 51 has a texture, obtained by machining for example, to increase the coefficient of static friction between the movable bearing surface 51 and a face 14 of the blade 10.

[0069] Preferably, the movable jaw 50 comprises a reinforcement portion 53 contiguous to the two lateral edges 52 and preferably perpendicular to said two lateral edges 52, so that said reinforcement portion 53 is parallel to the movable bearing surface 51. In this latter configuration, the movable bearing surface 51 is coupled to one end of the lateral edges 52 and the reinforcement portion 53 is coupled to the other end of the lateral edges 52. In such a preferred embodiment, the movable bearing surface 51, the lateral edges 52 and the reinforcement portion 53 define an opening in the movable jaw 50.

[0070] The tooling 1 of the invention comprises pressure means 70 for moving the movable jaw 50 and for pressing for example a platform 12 of a blade 10 between the movable jaw 50 and the fixed jaw 40. The pressure means 70 ensures the tightening and loosening of the blade 10 in the tooling. Typically, during the tightening action of an element 10 to be welded (blade 10 for example), under the effect of the pressure means 70, the movable bearing surface 51 exerts a force on the platform 12 of the blade 10 against the support surface 41 which is opposite said movable bearing surface 51. The platform 12 is retained firmly by tightening two parallel faces 14 of the platform 12. Preferably, the pressure means 70 are electric, pneumatic or hydraulic cylinders 71 which can develop either a force directly applied to the movable jaw 50, or a torque which through a screw will be transformed into a force on the movable jaw 50. The cylinders 71 are for example two or four in number and are preferably located at the ends of the arms 32 of the fixed jaw 30. The arms 32 of the fixed jaw 30 are preferably arranged in such a way that the cylinders 71 are integrated into the tooling 1. In the configuration with two cylinders 71, each of them applies a force on either side of the movable jaw 50 so that if one cylinder 71 pushes the movable jaw 50 then the other cylinder 71 pulls it. In the configuration with four cylinders 71, they preferably work in pairs, two that push the movable jaw 50 and two that pull it in order to double the transmitted force. The force is transmitted between each cylinder 71 and the movable jaw 50 by means of a piston 72. The pistons 72 are preferably arranged so as to transmit a force strictly parallel to the arms 32. Preferably, the cylinders 71 are controlled by a control unit. This control unit can itself be controlled by an algorithm so as to automate the procedure for tightening and loosening the blade 10 in the tooling 1. Thus, the tightening force, the cycle time between the tightening and loosening and other parameters relevant to the welding operation can be pre-programmed and then transmitted to the control unit.

[0071] FIG. 2 shows the tooling 1, according to an embodiment identical to that shown in FIG. 1, in which there is a blade 10 to be welded and other blades 10′ already welded. The distance d between the arms 32 of the fixed jaw 30 and the depth of the tooling 1 are sufficient to completely accommodate a blade 10. The orientation of the arms 32 of the tooling 1 allows to simultaneously contain a plurality of blades 10 aligned on the drum 20. The configuration of the tooling 1 is such that the already welded blades 10′ can be contained within the tooling 1 without contact with it. The blade 10 to be welded is contained between the fixed jaw body 40 and the movable jaw 50. The adjacent (already welded) blade 10′ which is on the side of the movable jaw 50 is preferably contained without contact in the opening described by the movable bearing surface 51, the lateral edges 52 and the reinforcement portion 53 of the movable jaw 50. Preferably, the portion that comprises the movable bearing surface 51 and the reinforcement portion 53 have an identical thickness.

[0072] In normal use of the tooling 1 for welding a blade 10 to a drum 20, the platform 12 of the blade 10 is preferably parallel to the central part 31 and located at the upper end of the arms 32 (the central part 31 being located at the lower end of the arms 32), the functional part 13 of the blade 10 is preferably contained between the arms 32 and the assembly portion 15 is preferably located outside the tooling 1.

[0073] FIG. 3 illustrates the manner in which the tooling 1, the vibrating plate 60 and a drum 20 are arranged during the welding operation according to a preferred embodiment of the invention. Typically, the drum 20 of a low-pressure compressor of a turbomachine consists of a plurality of stages, each comprising a row of blades 10. As a stage of the drum 20 is circular, the blades 10 are aligned along the stage. Thus, when welding a blade 10 to a drum stage 20, the arms 32 of the tooling 1 are arranged in a direction tangential to the drum stage 20 so that the row of blades 10 can be contained between the arms 32. The assembly portion 15 faces the drum 20 and the functional portion 13 leaks from it.

[0074] Preferably, the tooling 1 is coupled to the vibrating plate 60 by means of pins 61. The pins 61 are attached to the lower part of the tooling 1, preferably to the central part 31, and are intended to be received by holes 62 in the vibrating plate 60 upon coupling.

[0075] The vibrating plate 60 is itself coupled to a friction welding machine. The vibrating plate 60 is arranged to provide tangential vibration relative to the drum 20 but also allows the tooling 1 to be moved away from and towards the drum 20, preferably in an automated manner. Once the blade 10 is tightened in the tooling 1, the vibrating plate 60 can move the blade 10 towards the drum 20 so as to bring them into contact. When the welding is complete and the blade 10 is tightened, the tooling 1 is moved away from the drum 20 and releases the welded blade 10.

[0076] FIG. 4 shows a portion of a drum 20 to which a blade 10 is welded in one embodiment. The platform 12 serves essentially as a means of gripping and positioning the blade 10 in a plane parallel to the plane of orbital or linear motion. Preferably, the assembly portion 15, which corresponds to a protrusion under the platform 12 is intended to be welded to the drum 20. This assembly portion 15 comprises an assembly surface 11 intended to be brought into contact with an assembly surface 21 belonging to an assembly portion 22 of the drum 20. The assembly portion 22 of the drum 20 also corresponds to a protrusion of the receiving area on the outer wall 23 of the drum 20.

[0077] In summary, the invention may be described as follows.

[0078] A tooling 1 for holding a blade 10 during friction welding thereof to a rotor element 20 of a turbomachine of an aircraft and comprising:

[0079] a fixed jaw 30 comprising:

[0080] a central part 31;

[0081] two arms 32 separated by a distance d for receiving at least a portion of said blade 10;

[0082] a fixed jaw body 40 comprising bearing surfaces 41 and a bore 42 for receiving at least a portion of said blade 10, the bearing surfaces 41 being intended to come into contact with said blade 10;

[0083] a movable jaw 50 comprising a movable bearing surface 51 for coming into contact with said blade 10;

[0084] pressure means 70 for moving said movable jaw 50 towards the fixed jaw body 40 for pressing said blade 10.