Offset crimp insert and its crimping process

Abstract

Offset crimp insert and its crimping method An aspect of the invention relates to an offset insert (3) to be crimped into a composite turbomachine element comprising on the one hand a head (31) comprising an internal surface (310), an external surface (311) opposite the internal surface (310), an external peripheral edge (313) connecting the internal surface (310) to the external surface (311), and on the other hand a cylindrical shaft (32) along a central axis (y), extending from the internal surface (310) of the head (31) in an axial direction to an external axial end (321). The insert further comprises a fixing hole (30) centered along an adjustment axis (x) parallel to the central axis (y) extending from the outer surface (311) to the outer axial end (321) of the shaft (32), characterized in that the adjustment axis (x) of the fixing hole (30) is offset by at least 1 mm with respect to the central axis (y) of the shaft (32). Figure to be published with the abbreviation: Figure 3d

Description

Title of the invention: Offset insert for crimping and its crimping method TECHNICAL FIELD OF THE INVENTION

[0001] The technical field of the invention is that of inserts to be crimped into bodies, in particular composite bodies in the field of aeronautics.

[0002] The present invention relates to an offset insert and its crimping method for fitting a fixing axis into an orifice of a body having an axis off-center relative to the fixing axis. TECHNOLOGICAL BACKGROUND OF THE INVENTION

[0003] Inserts are known which are crimped into orifices of a part to fix another part to the part by means of the insert such as for example a fan casing with equipment. Indeed, a part, such as a fan casing, can have a body 2 comprising numerous cylindrical insert orifices 20 often accompanied by a counterbore 21 with crimping of an insert 1 in the insert orifice 20 such as that shown in a section in the casing in [Fig. 1a] to allow the fixing of equipment. The insert 1 comprises a head 11, a cylindrical barrel 12 extending from the head 11 and a fixing orifice 10 coaxial along an axis X with the cylindrical barrel 12 (coaxial). The fixing orifice 10 opens onto an external surface of the head 11 and onto an external axial end surface of the barrel 12 opposite the head 11. The cylindrical barrel 12 comprises an external diameter substantially equal to that of the insert orifice 20 of the body 2. [Fig.[Fig. 1b] represents the case of a well-positioned X axis of the insert orifice 20, however it happens that the X axis of the cylindrical insert orifice 20 (following manufacturing errors) is misaligned with respect to a nominal theoretical axis T, as represented in [Fig. 1b], which can prevent the installation of the other part, for example equipment.

[0004] Thus, if the drilling is carried out with too great a location deviation (for example beyond the manufacturing tolerance limits of the body), a center distance E between the nominal theoretical axis T and the axis X of the insert orifice 20, can induce a clash during assembly or induce unauthorized play. This results in a part being rejected due to a drilling having a location anomaly.

[0005] Such scrap is expensive, especially in the case of a composite body such as that of a fan casing. One solution consists of re-drilling the insert hole of the body along the nominal theoretical axis T according to a second diameter equal to the sum of the value of the center distance and the initial diameter and integrating an insert having a shaft according to this second diameter, however such a solution is on the one hand difficult to achieve due to the insert hole causing bending on the drilling tool and on the other hand resulting in an insert hole diameter that is too large in certain cases. Summary of the invention

[0006] The invention offers a solution to the problems mentioned above, by making it possible to integrate an insert having a fixing orifice off-center with respect to the barrel to reduce or cancel the difference between the nominal theoretical axis T (hereinafter called the nominal axis since it is no longer theoretical) and the Y axis of the fixing orifice of the insert.

[0007] One aspect of the invention relates to an offset insert to be crimped into a composite turbomachine element comprising: • a head comprising: • an internal surface, • an external surface opposite the internal surface • an external peripheral edge connecting the internal surface to the external surface, • a cylindrical shaft along a central axis, extending from the internal surface of the head in an axial direction to an external axial end, • a fixing hole centered along an adjustment axis parallel to the central axis extending from the external surface to the external axial end of the barrel, characterized in that the adjustment axis of the fixing hole is offset by at least 1 mm relative to the central axis of the barrel.

[0008] Thanks to the invention, since the positioning of the barrel of an insert on the body is completely dependent on that of the insert orifice, the fact of having a fixing orifice off-center with respect to that of the barrel makes it possible to approach or align the adjustment axis x of the fixing orifice with the nominal axis X without increasing the diameter as much as by re-drilling the insert orifice to align it with the nominal axis X. The misalignment is predetermined, that is to say that it comprises a center distance having a value greater, for example at least 5 times greater than a manufacturing tolerance of the insert, thus for example an off-center insert having a manufacturing tolerance + or -0.01 mm can have an axis y of the fixing orifice offset by 0.1 mm (center distance) from the central axis x of the barrel.

[0009] In addition to the characteristics which have just been mentioned in the preceding paragraph, the offset insert to be crimped according to one aspect of the invention may have one or more additional characteristics among the following, considered individually or according to all technically possible combinations: • According to one embodiment, the offset insert comprises an angular displacement stop extending from the external surface, offset from the central axis. This stop makes it possible to easily pivot the offset insert so as to bring even align the adjustment axis x of the fixing hole and the nominal axis X. • According to an example of this embodiment, the offset insert comprises at least one notch in the head forming at least the angular displacement stop. According to this example, the head may comprise two holes, each closer to the central axis than to the other hole. Each hole thus forms a stop for a tool comprising pins arranged in each hole, thus allowing rotation along the central axis y of the offset insert and thus approaching or aligning the adjustment axis x of the fixing hole and the nominal axis X. • According to another example of this embodiment, the insert comprises at least one planar shape on the peripheral edge of the head forming a stop. • According to one embodiment, the fixing hole is threaded. This makes it easier to mount an accessory on one side of a body (without handling a nut or other on the other side of the body). • According to one embodiment, the external peripheral edge of the head is cylindrical along the central axis.

[0010] A second aspect of the invention relates to a set of offset crimping inserts comprising a plurality of groups of offset crimping inserts, in which each group of inserts comprises inserts according to the first aspect of the invention with the same center distance value between the central axis of the barrel and the adjustment axis of the fixing orifice and in that each offset crimping insert of a group has a center distance different from the center distance of the offset inserts of another group. Thus each group is different from another group in that the center distance value between the central axis of the barrel and the adjustment axis of the fixing orifice of each insert of a group is different from this center distance value of the inserts of the other groups. This allows the offset insert to be crimped to be adapted according to the center distance value measured between the nominal axis X and the initial axis X of the through cylindrical insert orifice.

[0011] A third aspect of the invention relates to a composite turbomachine element comprising: • a body comprising a cylindrical insert orifice opening along an initial axis, • an insert according to the first aspect of the invention in a crimped state comprising its barrel comprising a part housed in the insert orifice of the body, such that the central axis of the barrel is centered on the initial axis and a part crimped against the body extending between the axial end of the barrel and the part housed in the orifice insert. The head and the end of the insert barrel each have a diameter larger than the diameter of the insert hole and therefore of the portion of the barrel inserted into that insert hole. • According to one embodiment, the element is an aeronautical part comprising a composite body, for example a fan casing. • According to one embodiment, the body comprises a first face and a second face, the insert orifice opens from the first face to the second face and in that the first face comprises a first surface and a countersink joining the insert orifice to the first surface and the second face comprises a second surface and a counterbore joining the insert orifice to the second surface, the head of the insert being in the countersink with its internal surface in contact with a surface for receiving the countersink and its external surface is flush with the second surface, flush with the second surface and the crimped part of the barrel being in contact with the countersink.

[0012] A fourth aspect of the invention relates to a method of crimping an offset insert according to the first aspect of the invention or according to the set of inserts according to the second aspect of the invention, on a body comprising a cylindrical insert orifice opening along an initial axis comprising the steps of: • Measuring a center distance between the initial axis and a nominal axis, • Choice of an insert including a center distance between the adjustment axis and the central axis of the barrel corresponding to the measured center distance, • Drilling the body along the initial axis to enlarge the diameter of the insert hole according to a diameter of the barrel of the chosen offset insert, • Insertion of the insert with the adjustment axis aligned with the nominal axis, • Crimping the insert onto the body, forming a single piece.

[0013] Thus, there is no difficulty in drilling, since the drilling is carried out along the initial axis Y of the insert orifice, while making it possible to compensate for the center distance between this initial axis Y and the nominal axis X by moving the adjustment axis x of the insert fixing orifice.

[0014] According to one embodiment, the step of inserting the insert with the adjustment axis on the nominal axis comprises: • A sub-step of inserting the barrel of the chosen insert into the insert hole, • A sub-step of pivoting the chosen insert having its barrel inserted, according to its central axis to align the adjustment axis with the nominal axis. In particular, this pivoting can be achieved by means of a screw or an axis in the fixing hole or by means of a tool pressing against a stop on the insert, for example two studs in two holes, each forming a notch in the head.

[0015] The invention and its various applications will be better understood upon reading the following description and examining the accompanying figures. BRIEF DESCRIPTION OF THE FIGURES

[0016] The figures are presented for information purposes only and in no way limit the invention.

[0017] [Fig. 1a] shows a schematic representation, according to a section of an insert crimped according to the prior art in a body.

[0018] [Fig.lb] shows a schematic representation, according to a section of an insert according to the prior art crimped in a body having an insert orifice offset from the nominal tolerance.

[0019] [Fig.2a] shows a schematic representation of an axial view of the side of a barrel of an offset insert according to an example of a first embodiment.

[0020] [Fig.2b] shows a schematic representation of an axial view from the side of a head of the offset insert of [Fig.2a].

[0021] [Fig.2c] shows a schematic representation of an axial section of the insert misaligned.

[0022] [Fig.3a] shows a schematic representation of an axial section of a body comprising an insert hole offset from a nominal axis.

[0023] [Fig.3b] shows a schematic representation of an axial section of the body of the [Fig.3a] including an insert hole.

[0024] [Fig.3c] shows a schematic representation of an axial section of the body comprising an insert according to the example of figures 2a, 2b, 2c in the enlarged offset insert hole.

[0025] [Fig.3d] shows a schematic representation of an axial section of the offset insert crimped into the orifice of the body of [Fig.3c]. DETAILED DESCRIPTION

[0026] The figures are presented for information purposes only and in no way limit the invention.

[0027] A first aspect of the invention which will be described relates to an offset insert, an example of a first embodiment of which is shown in different views in Figures 2a, 2b, 2c. A second aspect of the invention relates to a set of offset inserts to be crimped and is explained below. A third aspect of the invention relates to a part, an example of which is shown in [Fig.3d], comprising a body and an offset insert according to the example of Figures 2a, 2b, 2c, crimped in an enlarged insert orifice. A fourth aspect of the invention explained below relates to a method of crimping an offset insert, steps of which are explained in correlation with Figures 3a, 3b, 3c and 3d.

[0028] The offset crimping insert 3 according to the first aspect of the invention comprises a head 31 comprising an internal surface 310 intended to bear against a surface of reception 430 of a body 4 as shown in Figures 3a to 3d.

[0029] The head 31 further comprises an external surface 311 opposite the internal surface 310 and an external peripheral edge 313 connecting the internal surface 310 to the external surface 311. In this case, in this example the external peripheral edge 313 is cylindrical, but could have other shapes, such as the external surface is a hexagon or a square etc.

[0030] The offset crimping insert 3 comprises a cylindrical barrel 32 along a central axis y extending from the internal surface 310 of the head 31 in an axial direction to an external axial end 321 of the barrel 32. The axial end 321 is located opposite the external surface 311 of the head 31 of the offset insert 3. The axial end is in this example a flat surface radial relative to the central axis y.

[0031] The inner surface 310 and the outer surface 311 are also in this example a flat surface radial with respect to the central axis y and are centered with this central axis y. The inner surface 310 therefore has a crown shape.

[0032] The offset crimping insert 3 further comprises a fixing orifice 30 centered along an adjustment axis x parallel with the central axis y. The fixing orifice 30 extends from the external surface 311 to the external axial end 321 of the 32. The adjustment axis x of the fixing orifice 30 is offset by at least 0.1 mm relative to the central axis y of the barrel 32.

[0033] In this example, the fixing hole 30 is tapped all the way through but could be tapped only partially. The fixing hole 30 can also be smooth, i.e. delimited by a cylindrical surface.

[0034] In this embodiment, the offset insert 3 comprises an angular displacement stop 33, here two non-opening holes visible in [Fig.3b], making it possible to insert two pins of a tool to pivot along the central axis y of the offset insert 3 as explained below.

[0035] In the example shown in Figures 3a, 3b, 3c, the adjustment axis x is offset from the central axis y by a distance equal to approximately the root of two times the radius, i.e. V2r, r being the radius of the adjustment orifice 30, but can be offset by other values, such as 0.1 mm, 0.2 mm, etc. The center distance between the adjustment axis x and the central axis y is predetermined, i.e. it falls outside the manufacturing tolerances of the insert.

[0036] According to the second aspect of the invention, the set of offset inserts to be crimped comprises a plurality of groups of offset inserts 3 to be crimped according to the first aspect of the invention, for example that of the first example. Each group of inserts comprises offset inserts 3 with the same center distance value between the central axis y of the barrel 32 and the adjustment axis x of the fixing orifice 30. Each group comprises offset inserts 3 having the same center distance, that is to say that each offset insert 3 of a group has a center distance value between the central axis x of the barrel 32 and the adjustment axis y of the fixing orifice 30 different from a center distance value of each offset insert 3 of another group. For example, the set comprises about twenty groups with an increment of 0.1 mm center distance between group N and group N+1, i.e. with a center distance difference of 0.1 mm for the 1st group, 0.2 mm for the second group, etc. This makes it possible to adapt the offset insert to be crimped 3 according to the center distance value measured between the nominal axis X and the axis X of the cylindrical insert orifice emerging 40 of a body 4 of a part in which the offset insert to be crimped 3 must be crimped like the example shown in [Fig. 3d] according to the third aspect of the invention.

[0037] The part according to this third aspect of the invention comprises an offset insert 3 in a state crimped in a cylindrical insert orifice 40 along an initial axis Y emerging, referenced in [Fig.3b], from a body 4 of the part.

[0038] The part therefore comprises the body 4 comprising the insert orifice 40 and the offset insert crimped 3 in this insert orifice 40.

[0039] The crimped offset insert 3 comprises a housed portion 324 of the barrel 32, extending from the internal surface 310 of the head 31 into the insert orifice 40 of the body 4 such that the central axis y of the barrel 30 is centered on the initial axis Y.

[0040] The barrel 32 further comprises a portion 320 crimped against the body 4 of the part, extending from the axial end 321' to the housed portion 324. The central axis y of the barrel 30 is centered on the initial axis Y. The crimped portion 320 has undergone plastic deformation such that the end 321' of the barrel 30 comprises a diameter larger than the diameter of the insert orifice and therefore that portion 324 housed in the insert orifice 40 (unlike the case of the offset insert 3 to be crimped). The offset insert 3 is therefore made of a material allowing crimping such as stainless steel.

[0041] In this example, the body 4 is made of composite and forms, with inserts (at least one of which is an offset insert) crimped into insert orifices, an aeronautical part such as a fan casing.

[0042] The body 4 comprises a first face 4a and a second face 4b, the insert orifice 40 opens from the first face 4a to the second face 4b.

[0043] The first face 4a comprises a first surface 41a. In this example, the first surface 41a is flat in a plane perpendicular to the initial axis Y and a milling 43a joining the insert orifice 40 to the first surface 41a. The milling is by definition a concave conical surface. The crimped portion 320 of the barrel 32 is in contact with the milling 43a. In particular, in this example, the surface of the axial end 321' is flush with the first surface 41a.

[0044] The second face 4b comprises a second surface 41b and a counterbore 43b joining the insert orifice 40 to the second surface 41b. The counterbore 43b comprises the receiving surface 430 having a flat surface perpendicular to the initial axis Y in contact with the internal surface 310 of the head 31 and a cylindrical surface surrounding the peripheral edge 313 of the head 31. The cylindrical surface joins the receiving surface 430 to the second surface 41b. The head 31 of the offset insert 3 is housed in the counterbore 43b with its external surface 311 flush with the second surface 41b.

[0045] As can be seen in [Fig.3d], the adjustment axis x is coaxial with a nominal axis X, thus avoiding rejecting the part.

[0046] The method of crimping an offset insert according to a fourth aspect of the invention will now be described.

[0047] The crimping method will be described in relation to the offset insert 3 and the body 4 according to the example shown in the figures.

[0048] The crimping method comprises a step of measuring a center distance E visible in [Fig.3a], between a nominal axis X and an initial axis Y of the insert orifice 40. In fact, the insert orifice 40 is poorly located (setting error for example of the body 4) and should have its initial axis aligned with the nominal axis X. For example the measured center distance E is 0.5 mm.

[0049] The crimping method comprises a step of choosing an offset insert 3 comprising a center distance E between the adjustment axis x of the fixing orifice 30 and the central axis y of the barrel 32 corresponding to the measured center distance E. Thus, an operator or a machine will take an offset insert 3 from a group of inserts having a center distance closest to that measured. For example, an offset insert 3 from a group having a center distance of 0.5 mm.

[0050] The crimping method comprises a step of drilling the body 4 along the initial axis Y to enlarge the diameter of the insert orifice 40 according to a diameter of the barrel 32 of the chosen offset insert 3. For example, if the barrel of the chosen offset insert 3 has a diameter of 3 cm, the drilling can be carried out with a drill bit of 3 cm diameter or 3.1 cm for example. As visible in [Fig.3b], this step can comprise, if necessary, a sub-step of milling and countersinking to carry out the countersinking and countersinking on the body 4.

[0051] The crimping method further comprises a step of inserting the offset insert 3 with the adjustment axis x aligned with the nominal axis X in the insert orifice 40. This step may comprise a sub-step of inserting the barrel 32 of the selected offset insert 3 into the cylindrical orifice 40 and a subsequent sub-step of pivoting the selected offset insert 3 along its central axis y until the adjustment axis x is aligned with the nominal axis X. In particular, this pivoting sub-step may be carried out using the angular displacement stop (in this case the two non-opening holes 33). Of course, this step can be carried out according to another example by inserting the barrel 32 of the offset insert 3 into the insert orifice 40 by having the adjustment axis x directly aligned with the nominal axis X or by turning the offset insert 3 using the fixing orifice (since the latter is not aligned with the central axis y, for example). example using a screw or a rod.

[0052] Finally, the method comprises a step of crimping the offset insert 3 onto the body 4, together forming a part. The crimping comprises a plastic deformation of the end of the barrel 32 towards the body 4 until the crimped portion 320 is sufficiently deformed to be at least in contact with the milling of the body 4.

[0053] Unless otherwise specified, the same element appearing in different figures has a single reference.

Claims

Claims

1. Offset insert (3) to be crimped into a composite turbomachine element comprising: - a head (31) comprising: • an internal surface (310), • an external surface (311) opposite the internal surface (310) • an external peripheral edge (313) connecting the internal surface (310) to the external surface (311), - a cylindrical barrel (32) along a central axis (y), extending from the internal surface (310) of the head (31) in an axial direction to an external axial end (321), - a fixing orifice (30) centered along an adjustment axis (x) parallel to the central axis (y) extending from the external surface (311) to the external axial end (321) of the barrel (32) characterized in that the adjustment axis (x) of the fixing orifice (30) is off-center of at least 1mm relative to the central axis (y) of the barrel (32).

2. Offset insert (3) according to the preceding claim comprising at least one angular displacement stop (33) extending from the external surface (331) offset from the central axis (y).

3. Offset insert (3) according to claim 1 or 2 in which the fixing orifice (30) is threaded.

4. Offset insert (3) according to any one of the claims in which the external peripheral edge (313) of the head (31) is cylindrical along the central axis (y).

5. Set of offset inserts (3) to be crimped comprising a plurality of groups of offset inserts to be crimped (3), in which each group of inserts comprises offset inserts to be crimped (3) according to one of the preceding claims with the same center distance value between the central axis (y) of the barrel (32) and the adjustment axis (x) of the fixing orifice (30) and in that each offset insert (3) to be crimped of a group has a center distance (E) different from the center distance (E) of the offset inserts (3) of another group.

6. Composite turbomachine element comprising: a body (4) comprising a cylindrical insert orifice (40) opening along an initial axis (Y), - an offset insert (3) according to one of claims 1 to 4, in a crimped state, comprising its barrel (30) comprising a part housed (324) in the insert orifice (40) of the body (4) such that the central axis (y) of the barrel (30) is centered on the initial axis (Y) and a crimped part (320) against the body (4) extending between the axial end (321) of the barrel (30) and the part (324) in the insert orifice (40).

7. Element according to the preceding claim, in which the element is an aeronautical part whose body (4) is made of composite, for example a fan casing.

8. Element according to the preceding claim, in which the body (4) comprises a first face (4a) and a second face (4b), the insert orifice (40) opens from the first face (4a) to the second face (4b) and in that the first face (4a) comprises a first surface (41a) and a countersink (43a) joining the insert orifice (40) to the first surface (41a) and the second face (4b) comprises a second surface (41b) and a countersink (43b) joining the insert orifice (40) to the second surface (41b), the head (31) of the offset insert (3) being in the countersink (43b) with its internal surface (310) in contact with a receiving surface (430) and its external surface (311) is flush with the second surface (41b) and the part crimped (320) of the barrel (32) being in contact with the milling (43a).

9. Method for crimping an offset insert according to one of claims 1 to 4 or according to the set of inserts according to claim 5, on a body (4) comprising a cylindrical insert orifice (40) opening along an initial axis (Y) comprising the steps of: - Measuring a center distance (E) between the initial axis (Y) and a nominal axis (X), - Choosing an offset insert (3) comprising a center distance (E) between the adjustment axis and the central axis corresponding to the measured center distance, - Drilling the body (4) along the initial axis (Y) to enlarge the diameter of the insert orifice (40) according to a diameter of the barrel (32) of the chosen offset insert (3), - Inserting the offset insert (3) with the adjustment axis (x) aligned with the nominal axis (X) in the insert hole, - Crimping of the offset insert (3) on the body (4) together forming a part.

10. A method according to the preceding claim, wherein the step of inserting the insert with the adjustment axis on the nominal axis comprises: - A sub-step of inserting the barrel of the chosen offset insert into the cylindrical orifice, - A sub-step of pivoting the chosen offset insert (3), along its central axis (y) until the adjustment axis (x) is aligned with the nominal axis (X).

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