Tooling for fixing a metal reinforcement to a leading edge of a turbomachine blade

Abstract

Tooling (100) for fixing a metal reinforcement (110) to the leading edge of a turbomachine blade (140), the metal reinforcement comprising a nose (111) intended to form the leading edge of the blade and flanges (112, 113) extending from the nose of the metal reinforcement and intended to extend from the leading edge towards the pressure-side and suction-side faces of the blade, characterised in that the tooling comprises a reinforcement support (120) intended to receive the metal reinforcement, while leaving the nose free (160) and being in contact with the flanges of the metal reinforcement, said reinforcement support comprising at least one notch (151) intended to receive a strap (150).

Description

[0001] Description

[0002] Title of the invention: Tooling for attaching a metal reinforcement to the leading edge of a turbomachine blade

[0003] Technical Field

[0004] The present invention relates to the general field of turbomachine blades equipped with a metallic reinforcement on their leading edge. More particularly, it relates to a tool and a method for attaching a metallic reinforcement to the leading edge of a turbomachine blade made of composite material.

[0005] Previous technique

[0006] It is known to equip the fan blades of a turbomachine, made of composite material, with a metallic reinforcement extending along the entire height of the blade. Such reinforcement protects the composite blade when a foreign object impacts the fan, such as when a bird is ingested by the turbomachine.

[0007] Currently, the metal reinforcements are manually assembled onto the leading edges of the blades. Specifically, the composite blade body is woven and then reinforced by injection molding. Next, its leading edge is machined and its surface is prepared for the application of an adhesive film. The metal reinforcement is then positioned on the adhesive film on the leading edge of the composite body. Straps are positioned along the leading edge to drive the metal reinforcement onto the composite body. A mallet can be used to further drive the reinforcement in. Finally, the composite body with the metal reinforcement is placed in an autoclave for curing, completing the blade manufacturing process.

[0008] However, this method has many drawbacks. Some metal reinforcements have a very tight internal cavity, making them even more difficult to position. A mallet is necessary in this case to drive the reinforcement in, but striking it in one spot can shift its position in other areas along the leading edge. Therefore, it is necessary to use the mallet repeatedly on the same points to drive the reinforcement in, which can damage or even tear the adhesive film underneath.

[0009] Furthermore, the thickness of glue present on the fins of the metal reinforcement is greater than at the leading edge, and we easily exceed the maximum thickness of glue which would limit the problems of adhesion and detachment of one fin when we bring the other fin closer to the blade.

[0010] Therefore, it would be desirable to have a tool and a method for fixing the metal reinforcement to the leading edge of the blade that eliminates the need for a mallet, and that allows the reinforcement fins to be held in place during installation in order to orient it correctly on the blade while having a more regular thickness of glue between the leading edge and the fins.

[0011] Description of the invention

[0012] The main purpose of the present invention is therefore to overcome the disadvantages of the aforementioned prior art, and more particularly to propose a tool for fixing a metal reinforcement on the leading edge of a blade as well as the method using the tool that allows one to do without a mallet and to regularize the thickness of glue all along the metal reinforcement.

[0013] According to the invention, this goal is achieved by means of a tooling for fixing a metal reinforcement on the leading edge of a turbomachine blade, the metal reinforcement comprising a nose intended to form the leading edge of the blade and fins extending from the nose of the metal reinforcement and intended to extend from the leading edge towards the intrados and extrados faces of the blade, characterized in that the tooling comprises a reinforcement support intended to receive the metal reinforcement, while leaving the nose free and being in contact with the fins of the metal reinforcement, said reinforcement support comprising at least one notch intended to receive a strap.

[0014] Thanks to the reinforcement support, the forces applied to the metal reinforcement for positioning and securing it to the leading edge of the blade are concentrated on the vanes rather than the nose. These forces are also applied along the entire length of the vanes on the leading edge of the blade, and not just at the points of contact with the mallet, thus preventing buckling and deformation of the metal reinforcement's vanes. This also prevents the metal reinforcement from moving on the leading edge of the blade during its attachment.

[0015] The notch(s) allow for the pre-positioning of one or more straps that will hold the reinforcement support, particularly the metal reinforcement, in place on the blade. Specifically, they allow these straps to be positioned parallel to the fins of the metal reinforcement and the leading edge of the blade. The notch(s) are, for example, cut into the reinforcement support to form a groove. The grooves thus formed have, for example, a depth of between 3 mm and 5 mm, for example 4 mm; and a width of between 30 mm and 50 mm, for example 35 mm.

[0016] According to a particular feature of the invention, the tooling comprises at least one counterform integral with the reinforcement support and intended to be present between the metal reinforcement and the reinforcement support.

[0017] The counterform allows the metal reinforcement to not be in direct contact with its support in order to absorb the geometric deformations of the metal reinforcement relative to the reinforcement support, transmit the forces applied to the reinforcement via the tooling and not degrade the surface of the metal reinforcement.

[0018] Preferably, the tooling includes two counterforms, placed on each side of the fins of the metal reinforcement between the metal reinforcement and the reinforcement support.

[0019] According to one embodiment of the invention, the counter-mold is made of silicone.

[0020] For example, the counterform is made of silicone with a thickness between 3 mm and 5 mm and has a Shore A hardness of 40.

[0021] The silicone mold can be a pre-molded silicone or a multi-layered silicone.

[0022] The silicone counterform can be glued to the internal walls of the reinforcement support. According to another embodiment of the invention, the counterform is formed by an inflatable bladder.

[0023] Using an inflatable bladder as a counterform, rather than a silicone one, reduces the force required from the strap(s) positioned in the notches on the reinforcement support, as some of the force is then transmitted by the inflatable bladder. The strap(s) would then only be needed to control the positioning of the metal reinforcement on the blade.

[0024] Furthermore, the removal of the tooling would be easier thanks to the deflation of the inflatable bladder.

[0025] According to a particular feature of the invention, the reinforcement support has a lock-shaped imprint.

[0026] The fact that the reinforcement support has a lock-shaped indentation helps prevent tooling from cracking.

[0027] According to another particular feature of the invention, the reinforcement support includes at least one window.

[0028] The presence of a window on the reinforcement support allows verification of the positioning of the metal reinforcement in the reinforcement support.

[0029] According to another particular feature of the invention, the tooling also includes a support for receiving a blade while leaving the leading edge of the blade unobstructed.

[0030] Another object of the invention is a method for attaching a metallic reinforcement to the leading edge of a turbomachine blade, implemented using tooling according to the invention, the method comprising:

[0031] the positioning of the metal reinforcement in the tooling reinforcement support and the positioning of the tooling on the leading edge of the blade, and the positioning of a strap on the notch of the tooling and around the blade and tightening the strap to apply pressure to the fins of the metal reinforcement.

[0032] The method according to the invention is applied to a "non-final" blade, that is, a blade without metallic reinforcement on its leading edge. The method according to the invention thus makes it possible to obtain a blade with metallic reinforcement on its leading edge.

[0033] According to a particular feature of the invention, when positioning the metal reinforcement in the reinforcement support, at least one end of the metal reinforcement is placed flush with the reinforcement support.

[0034] According to another particular feature of the invention, when positioning the metal reinforcement in the reinforcement support, at least one end of the metal reinforcement protrudes from the reinforcement support.

[0035] By leaving at least one end of the metal reinforcement protruding from the reinforcement support, it is possible to measure the head clearance, that is, to measure the clearance between the nose of the metal reinforcement and the reinforcement support.

[0036] It is therefore possible, when positioning the metal reinforcement in the reinforcement support, to place both ends of the metal reinforcement flush with the support; or to leave both ends of the metal reinforcement protruding from the support; or to leave one of the two ends of the metal reinforcement protruding from the support and to place the other end flush with the reinforcement support.

[0037] According to another particular feature of the invention, the method also includes positioning the blade in the blade support of the tooling while leaving the leading edge surfaces of the blade unobstructed.

[0038] According to another particular feature of the invention, the method also includes a step of applying glue to the leading edge surfaces of the blade before positioning the tooling on the leading edge of the blade.

[0039] This glue application step is, for example, carried out after the blade positioning step in the blade holder of the tooling. Brief description of the drawings

[0040] Other features and advantages of the present invention will become apparent from the description given below, with reference to the attached drawings which illustrate examples of embodiment without any limiting character.

[0041] [Fig. 1] Figure 1 schematically and partially represents a tool for fixing a metal reinforcement on a turbomachine blade according to an embodiment of the invention.

[0042] [Fig. 2] Figure 2 represents, schematically and partially, a cross-sectional view of the tooling of Figure 1.

[0043] [Fig. 3A] Figure 3A represents, schematically and partially, another embodiment of the tooling according to the invention.

[0044] [Fig. 3B] Figure 3B represents, schematically and partially, another embodiment of the tooling according to the invention.

[0045] [Fig. 3C] Figure 3C schematically and partially represents another embodiment of the tooling according to the invention

[0046] [Fig. 4A] Figure 4A schematically and partially represents the positioning step of the metal reinforcement in the tooling according to one embodiment of the invention.

[0047] [Fig. 4B] Figure 4B schematically and partially represents the tooling positioning step on the blade according to one embodiment of the invention.

[0048] [Fig. 4C] Figure 4C schematically and partially represents the step of positioning straps around the tooling and the blade and tightening the straps to apply pressure to the fins of the metal reinforcement according to an embodiment of the invention.

[0049] Description of embodiments Figures 1 and 2 represent, schematically and partially, a tool 100 for fixing a metal reinforcement 110 on a turbine blade 140 according to a first embodiment of the invention, Figure 2 being a cross-sectional view of the tool of Figure 1.

[0050] The metal reinforcement 110 includes a nose 111 which is intended to form the leading edge of the blade 140 and fins 112, 113 on either side of the nose 111 which are intended to extend from the nose 111 on the intrados and extrados faces of the blade 140.

[0051] The tooling 100 includes a reinforcement support 120 which receives the metal reinforcement 110 while leaving the nose 111 of the reinforcement 110 free and in contact with the fins 112, 113. In particular, a clearance 160 is present between the nose 111 of the metal reinforcement 110 and the reinforcement support 120. In other words, the reinforcement support 120 includes a nose and fins, the nose of the reinforcement support receiving the nose 111 of the metal reinforcement 110 in such a way that the clearance 160 is present between the nose 111 of the metal reinforcement 110 and the nose of the reinforcement support 120, and the fins of the reinforcement support being in contact with the fins 112, 113 of the reinforcement 10.

[0052] The reinforcement support 120 includes a notch 151 formed in this embodiment by a groove cut into the reinforcement support 120. The notch 151 is intended to receive and / or serve as a positioning reference for a strap 150 which will be placed between the reinforcement support 120 and the blade 140 when the metal reinforcement 110 is fixed to the blade 140.

[0053] When the strap 150 is placed in the notch 151 and tightened, it allows a pressure force F to be exerted on the whole of the reinforcement support 120, in particular on the fins 112, 113 of the metal reinforcement 110, in particular via the fins of the reinforcement support which are in contact with the fins 112, 112 of the reinforcement 110.

[0054] The tooling 100 may also include at least one counterform 130, placed between the metal reinforcement 110 and the reinforcement support 120. In particular, in this embodiment, two counterforms 130 are present on either side of the fins 112, 113 of the metal reinforcement to leave the nose 111 of the reinforcement 110 free. These counterforms 130 may be made of silicone, for example a silicone having a Shore A hardness of 40. They may have a thickness of between 3 mm and 5 mm.

[0055] More generally, these counterforms 130 can be made of a flexible elastomer material allowing the pressure to be distributed on the fins 112, 113 of the metal reinforcement 120 while following their shapes, and resistant to at least 180 °C over several cycles.

[0056] Alternatively, the 130 counterforms can be formed by inflatable bladders.

[0057] Figures 3A, 3B and 3C represent, schematically and partially, different embodiments of the tooling of the invention.

[0058] In the three embodiments of figures 3A, 3B and 3C, the metal reinforcement 310 is placed in the reinforcement support 320 which leaves the nose 311 of the reinforcement free, while being in contact with the fins 312, 313 of the reinforcement 310. A clearance 360 ​​is therefore present between the nose 311 and the reinforcement support 320.

[0059] Furthermore, as in the embodiment of Figure 1, one or two counterforms 330 can be placed on the fins 312, 313 of the metal reinforcement so that the reinforcement 310 is not in direct contact with the reinforcement support 320.

[0060] In the embodiment of Figure 3A, the metal reinforcement 310 is placed flush with one end of the reinforcement support 320.

[0061] In the embodiment of Figure 3B, the reinforcement support 320 includes a window 380 which allows checking the positioning of the metal reinforcement 310 on the blade, as well as the clearance 360 ​​between the nose 311 of the metal reinforcement 310 and the reinforcement support 320.

[0062] In the embodiment of Figure 3C, the metal reinforcement 310 extends beyond the reinforcement support 320 at a second end 372. This makes it easier to measure the clearance 360 ​​between the nose 311 of the reinforcement 310 and the reinforcement support 320. Figures 4A, 4B and 4C schematically and partially represent the method of fixing the metal reinforcement to the blade, and more particularly the positioning of the metal reinforcement and its support on the leading edge of the blade.

[0063] The process includes, as illustrated in Figure 4A, a step 401 of positioning the metal reinforcement 410 in the reinforcement support 430. As explained with reference to the preceding figures, the tooling may include one or more counterforms 430 attached to the reinforcement support 420, which prevent direct contact between the support 420 and the reinforcement 410. During step 401, if the reinforcement support 420 includes windows 481, 482, 483, the correct positioning of the metal reinforcement 410 in its support 420 can be verified, as well as the clearance 460 between the nose 411 of the reinforcement 410 and the reinforcement support 420. Furthermore, when positioning the reinforcement 410 in its support 420, the metal reinforcement 410 can be placed at one end 471 flush with the reinforcement support 420. Alternatively, at a second end 472, leave reinforcement 410 protruding from support 420.

[0064] The reinforcement support 420 covers the entire surface of the fins 412, 413 of the metal reinforcement 410, except for the second end 472 where the metal reinforcement 410 protrudes.

[0065] During this step 401, the metal reinforcement 410 was placed at a first end 471 flush with its support 420 and at a second end 472, the metal reinforcement 410 was left protruding from the support 420. However, it is also possible to leave the metal reinforcement 410 protruding from the support 420 at both ends 471, 472 or conversely to place it flush with the support 420 at both ends 471, 472.

[0066] The first end 471 can correspond to the foot 415 of the metal reinforcement 410 and the second end 472 to its head 414, the foot 415 of the reinforcement 410 being its end intended to be closest to the foot 442 of the blade 440 and the head 414 of the reinforcement 410 being its end intended to be placed near the apex 441 of the blade 440. Then, the method includes, as illustrated by Figure 4B, a step 402 of positioning the tooling, in particular the reinforcement support 430, on the blade 440. The reinforcement support 420 is thus placed over the entire surface of the leading edge of the blade 440, so that the nose 411 of the metal reinforcement forms the leading edge and the fins 412, 413 of the reinforcement 410 extend from the nose 411 towards the faces Intrados and extrados of dawn 440.

[0067] Finally, the process includes, as illustrated in Figure 4C, a step 403 of positioning straps 450 around the tooling, in particular the reinforcement support 420, and the blade 440, as well as tightening the straps 450 to apply pressure to the fins 412, 413 of the metal reinforcement 410. The reinforcement support 420 has three notches 451, 452, 453. Therefore, during this step 403, three straps 450 are positioned at these notches 451, 452, 453. The straps 450 thus positioned are then tightened so as to apply a pressure force to the reinforcement support 420 and to the fins 412, 413 of the metal reinforcement 410.

[0068] The straps 450 can be positioned perpendicular to the curvature of the metal reinforcement 410. These straps 450 thus make it possible to distribute the pressure forces evenly on the fins 412, 412 of the metal reinforcement 410 and not to apply force on the nose 411.

[0069] By positioning the straps 450 perpendicular to the curvature of the metal reinforcement 410, a better distribution of the adhesive between the reinforcement 410 and the blade 440 is achieved, and more specifically, a more homogeneous adhesive thickness is obtained. Thus, thanks to the tooling and process according to the invention, the adhesive thickness now varies between 150 µm and 350 µm, whereas in the prior art, it could vary between 50 µm and 450 µm.

[0070] The process may also include a step of positioning the blade 440 in a blade support, leaving the leading edge surfaces of the blade 440 unobstructed. This step may be performed before or after step 401 of positioning the metal reinforcement 410 in its support 420, but before step 402 of positioning the reinforcement support 420 on the blade 440. The process may further include a step of applying adhesive to the leading edge surfaces of the blade, preferably performed after the step of positioning the blade 440 in its support.

[0071] Regardless of the embodiment, the tooling may include several notches for receiving a strap which is itself designed to encircle the blade and the reinforcement support in order to hold the metal reinforcement onto the blade. For example, the tooling may include three notches.

[0072] Regardless of the method of implementation, the metal reinforcement is made of a hard metal, for example titanium, stainless steel or a stainless steel alloy.

[0073] Regardless of the embodiment, the reinforcement support has a keyhole or omega Q shape. More generally, the reinforcement support has a shape that eliminates any force passing through the nose of the reinforcement to focus the forces on the fins.

[0074] Regardless of the embodiment, the tooling may include a blade support designed to receive the blade while leaving its leading edge clear.

[0075] Regardless of the embodiment, the strap(s) may be graduated or include a force measurement device. The graduation on the strap(s) and / or the force measurement device make it possible to define the force applied by the strap(s) to the fins of the metal reinforcement.

[0076] The forces exerted by the strap(s) on the metal reinforcement during its application to the leading edge of the blade can be known in advance, thanks to measurements on a reference model. This makes it easier to automate the placement and fastening of the metal reinforcement to the leading edge of the blade.

[0077] Regardless of the specific design, the strap(s) can be replaced by any device that allows the assembly forces of the metal reinforcement to be directed onto the blade. The advantage of straps is the ability to easily modify the direction of the forces applied to the reinforcement positioned on the blade.

Claims

Demands

1. Tooling (100) for attaching a metal reinforcement (110, 310, 410) to the leading edge of a turbomachine blade (140, 440), the metal reinforcement comprising a nose (111, 311, 411) intended to form the leading edge of the blade and fins (112, 113, 312, 313, 412, 413) extending from the nose of the metal reinforcement and intended to extend from the leading edge towards the intrados and extrados faces of the blade, characterized in that the tooling comprises a reinforcement support (120, 320, 420) intended to receive the metal reinforcement and comprising a nose and fins, the nose of the reinforcement support being intended to receive the nose (111) of the metal reinforcement (110) such that a gap (160, 360, 460) be present between the nose (111) of the metal reinforcement (110) and the nose of the reinforcement support, the fins of the reinforcement support being in contact with the fins of the metal reinforcement, said reinforcement support comprising at least one notch (151, 451, 452,453), and the tooling also comprising a strap (150, 450) intended to be placed on said at least one notch so as to exert a pressure force (F) on the reinforcement support.

2. Tooling according to claim 1, comprising at least one counterform (130, 330, 430) integral with the reinforcement support and intended to be present between the metal reinforcement and the reinforcement support.

3. Tooling according to claim 2, wherein the counterform is made of silicone.

4. Tooling according to claim 2, wherein the counterform is formed by an inflatable bladder.

5. Tooling according to any one of claims 1 to 4, wherein the reinforcement support has an omega-shaped recess for receiving the nose of the metal reinforcement.

6. Tooling according to any one of claims 1 to 5, wherein the reinforcement support comprises at least one window (380, 481, 482, 483).

7. Tooling according to any one of claims 1 to 6, also comprising a support for receiving a blade while leaving the leading edge of the blade unobstructed.

8. A method for attaching a metal reinforcement to the leading edge of a turbomachine blade implemented using tooling according to any one of claims 1 to 7, the method comprising: - the positioning (401) of the metal reinforcement in the tooling reinforcement support and the positioning (402) of the tooling on the leading edge of the blade, and - the positioning (403) of a strap on the notch of the tooling and around the blade and tightening the strap to apply pressure (F) on the fins of the metal reinforcement.

9. Method according to claim 8, wherein when positioning the metal reinforcement in the reinforcement support, at least one end (471) of the metal reinforcement is placed flush with the reinforcement support and the other end (372, 472) of the metal reinforcement protrudes from the reinforcement support.

10. A method according to any one of claims 8 or 9 in combination with claim 7, also comprising positioning the blade in the blade support of the tooling leaving the leading edge surfaces of the blade unobstructed.

11. A method according to any one of claims 8 to 10, also comprising a step of applying glue to the leading edge surfaces of the blade before positioning the tooling on the leading edge of the blade.

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