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 crimp insert 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 in an orifice of a body having an axis offset with respect to the fixing axis. TECHNOLOGICAL BACKGROUND OF THE INVENTION

[0003] It is known that inserts crimped into holes in a part are used to attach another part to the part via the insert, such as, for example, a blower housing with equipment. Indeed, a part, such as a blower housing, may have a body 2 comprising numerous cylindrical insert holes 20, often accompanied by a counterbore 21 with a crimped insert 1 into the insert hole 20, such as the one shown in a cross-section of the housing in [Fig. 1a], to allow the attachment of equipment. The insert 1 comprises a head 11, a cylindrical shaft 12 extending from the head 11, and a mounting hole 10 coaxial with the cylindrical shaft 12 along an axis X. The fixing orifice 10 opens onto an external surface of the head 11 and onto an external axial end surface of the shaft 12 opposite the head 11. The cylindrical shaft 12 has an external diameter substantially equal to that of the insert orifice 20 of the body 2. The [Fig.[Fig. 1b] represents the case of a well-positioned X-axis of the insert orifice 20; however, it sometimes happens that the X-axis of the cylindrical insert orifice 20 (due to manufacturing errors) is misaligned with respect to a nominal theoretical axis T, as shown in [Fig. 1b], which may prevent the installation of the other part, for example, equipment.

[0004] Thus, if the drilling is carried out with too large a deviation in location (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 hole 20 can induce a clash during assembly or result in an unauthorized clearance. This leads to the rejection of a part due to a drilling with an anomaly in location.

[0005] Such waste is costly, especially in the case of composite bodies such as that of a blower housing. One solution consists of re-drilling the insert hole of the body along the nominal theoretical axis T with a second diameter equal to the sum of the center distance and the initial diameter, and integrating an insert having a shaft with this second diameter. However, such a solution is difficult to implement due to the insert orifice causing a bend on the drilling tool and on the other hand resulting in an insert orifice diameter that is too large in some cases. Summary of the invention

[0006] The invention offers a solution to the problems mentioned above, by allowing the integration of an insert having a fixing orifice offset relative to the barrel to reduce or eliminate the gap between the nominal theoretical axis T (hereafter 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 to the internal surface • an external peripheral edge connecting the inner surface to the outer 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 1mm from the central axis of the barrel.

[0008] Thanks to the invention, since the positioning of the shaft of an insert on the body is completely dependent on that of the insert orifice, having a fixing orifice offset relative to that of the shaft 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 offset is predetermined, that is to say, it includes 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 offset insert having a manufacturing tolerance of + or -0.01mm can have a y-axis of the fixing orifice offset by 0.1mm (center distance) from the central axis x of the shaft.

[0009] In addition to the characteristics 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 from among the following, considered individually or according to all technically possible combinations: • In one embodiment, the offset insert includes an angular displacement stop extending from the outer surface, offset from the central axis. This stop allows the offset insert to be easily rotated so as to bring the adjustment axis x closer to or even align the fixing hole and the nominal axis X. • According to one example of this embodiment, the offset insert includes at least one notch in the head forming at least the angular displacement stop. According to this example, the head may include two holes, each closer to the central axis than the other hole. Each hole thus forms a stop for a tool comprising pins arranged in each hole, allowing rotation about the central axis y of the offset insert and thereby approaching or aligning the adjustment axis x with the mounting hole and the nominal axis X. • According to another example of this embodiment, the insert includes at least one flat shape on the peripheral edge of the head forming a stop. • In one embodiment, the fixing hole is tapped. This makes it easier to mount an accessory on one face of a body (without having to handle a nut or anything else on the other face of the body). • According to one embodiment, the outer peripheral edge of the head is cylindrical along the central axis.

[0010] A second aspect of the invention relates to an assembly of offset crimp inserts comprising a plurality of groups of offset crimp inserts, in which each group of inserts comprises inserts according to the first aspect of the invention with the same center-to-center distance between the central axis of the barrel and the adjustment axis of the fixing hole, and in that each offset crimp insert of one group has a center-to-center distance different from the center-to-center distance of the offset inserts of another group. Thus, each group is different from another group in that the center-to-center distance between the central axis of the barrel and the adjustment axis of the fixing hole of each insert in one group is different from this center-to-center distance of the inserts in the other groups. This allows the offset insert to be adapted 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 shaft including a portion housed in the insert orifice of the body, such that the central axis of the shaft is centered on the initial axis and a portion crimped against the body extending between the axial end of the shaft and the portion housed in the orifice of insert. The head and the end of the insert shaft each have a diameter larger than the diameter of the insert orifice and therefore of the part of the shaft inserted into this insert orifice. • According to one embodiment, the element is an aeronautical part comprising a composite body, for example a fan housing. • According to one embodiment, the body comprises a first face and a second face, the insert orifice is through the first face to the second face and in that the first face comprises a first surface and a milling 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 counterbore having its internal surface in contact with a receiving surface of the counterbore and its external surface flush with the second surface and the crimped part of the barrel being in contact with the milling.

[0012] A fourth aspect of the invention relates to a method for 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, onto 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, • Selection of an insert with 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 orifice according to the chosen offset insert shaft diameter, • Insert the insert with the adjustment axis aligned with the nominal axis, • Crimping the insert onto the body, together 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 catch up with 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 orifice, • 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 bearing against a stop of 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 illustrative purposes only and are in no way limiting of the invention.

[0017] [Fig. la] shows a schematic representation, according to a cross-section of an insert set according to the prior art in a body.

[0018] [Fig.lb] shows a schematic representation, according to a cross-section of a prior art insert set 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 shaft of an offset insert according to an example of a first embodiment.

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

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

[0022] [Fig.3a] shows a schematic representation of an axial section of a body including an insert orifice 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 including an insert as shown in Figures 2a, 2b, 2c in the enlarged offset insert orifice.

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

[0026] The figures are presented for illustrative purposes only and are in no way limiting of 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 various views in Figures 2a, 2b, and 2c. A second aspect of the invention relates to an assembly of offset inserts to be crimped, which 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 as shown in Figures 2a, 2b, and 2c, crimped into an enlarged insert hole. A fourth aspect of the invention, explained below, relates to a method for crimping an offset insert, some steps of which are explained in conjunction with Figures 3a, 3b, 3c, and 3d.

[0028] The offset crimp insert 3 according to the first aspect of the invention comprises a head 31 including an internal surface 310 intended to bear against a surface of reception 430 of a body 4 as represented 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 example, the external peripheral edge 313 is cylindrical, but could have other shapes, such as the external surface being a hexagon or a square, etc.

[0030] The offset crimp insert 3 comprises 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 of the shaft 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 radial flat surface with respect to the central axis y.

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

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

[0033] In this example, the mounting hole 30 is tapped along its entire length but could be tapped only partially. The mounting hole 30 can also be smooth, that is to say, delimited by a cylindrical surface.

[0034] In this embodiment, the offset insert 3 includes an angular displacement stop 33, here two blind holes visible on [Fig.3b], allowing two pins of a tool to be inserted to pivot about 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 twice the radius, i.e. V2r, r being the radius of the adjustment orifice 30, but can be offset by other values, such as 0.1mm, 0.2mm etc... the center distance between the adjustment axis x and the central axis y is predetermined, i.e. it is outside the manufacturing tolerances of the insert.

[0036] According to the second aspect of the invention, the set of offset crimp inserts comprises a plurality of groups of offset crimp inserts 3 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 between the central axis y of the barrel 32 and the adjustment axis x of the fixing hole 30. Each group comprises offset inserts 3 having the same center distance, that is to say, each offset insert 3 of a group has a center distance between the central axis x of the barrel 32 and the adjustment axis y of The fixing orifice 30 differs from the center-to-center distance of each offset insert 3 of another group. For example, the assembly comprises about twenty groups with a 0.1 mm increment of center-to-center distance between group N and group N+1, i.e., with a center-to-center distance difference of 0.1 mm for the first group, 0.2 mm for the second group, etc. This allows the offset crimp insert 3 to be adapted according to the center-to-center distance measured between the nominal axis X and the axis X of the cylindrical insert orifice 40 of a body 4 of a part into which the offset crimp insert 3 is to be crimped, as in 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 crimped state in a cylindrical insert orifice 40 along an initial axis Y opening, referenced on the [Fig.3b], from a body 4 of the part.

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

[0039] The offset insert 3 crimped includes a housed portion 324 of the shaft 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 shaft 30 is centered on the initial axis Y.

[0040] The barrel 32 further comprises a crimped portion 320 against the body 4 of the part, extending from the axial end 321' to the recessed 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 has a diameter larger than the diameter of the insert orifice and therefore larger than the recessed portion 324 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 suitable for crimping, such as stainless steel.

[0041] In this example, the body 4 is made of composite material and forms, with inserts (at least one of which is an offset insert) set into insert holes, an aeronautical part such as a blower housing.

[0042] The body 4 comprises a first face 4a and a second face 4b, the insert orifice 40 is open 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 joins 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 at 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 preventing the part from being rejected.

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

[0047] The crimping process 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 process includes 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. Indeed, the insert orifice 40 is incorrectly located (for example, a shimming error of the body 4) and should have its initial axis aligned with the nominal axis X. For example, the measured center distance E is 0.5mm.

[0049] The crimping process includes a step of selecting an offset insert 3 having a center distance E between the adjustment axis x of the fixing hole 30 and the central axis y of the barrel 32 corresponding to the measured center distance E. Thus, an operator or a machine will select an offset insert 3 from a group of inserts having a center distance closest to the measured one. For example, an offset insert 3 from a group having a center distance of 0.5 mm.

[0050] The crimping process includes a step of drilling the body 4 along the initial Y-axis to enlarge the diameter of the insert orifice 40 to a diameter of the shaft 32 of the selected offset insert 3. For example, if the shaft of the selected offset insert 3 has a diameter of 3 cm, the drilling can be carried out with a drill bit of 3 cm diameter or, for example, 3.1 cm. As shown in [Fig. 3b], this step may, if necessary, include a substep of milling and countersinking to perform the countersinking and milling on the body 4.

[0051] The crimping process further includes 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 include a substep of inserting the barrel 32 of the selected offset insert 3 into the cylindrical orifice 40 and a subsequent substep of pivoting the selected offset insert 3 about its central axis y until the adjustment axis x is aligned with the nominal axis X. In particular, this pivoting substep may be carried out using the angular displacement stop (in this case the two blind 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 hole 40, with the adjustment axis x directly aligned with the nominal axis X, or by rotating the offset insert 3 using the fixing hole (since the latter is not aligned with the central axis y). example using a screw or a rod.

[0052] Finally, the process includes a step of crimping the offset insert 3 onto the body 4, which together form a single piece. The crimping involves a plastic deformation of the end of the shaft 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 on different figures has a unique reference.

Claims

Demands

1. Offset insert (3) for crimping into a composite turbomachine element comprising: - a head (31) comprising: • an inner surface (310), • an outer surface (311) opposite the inner surface (310), • an outer peripheral edge (313) connecting the inner surface (310) to the outer surface (311), - a cylindrical shaft (32) about a central axis (y), extending from the inner surface (310) of the head (31) in an axial direction to an outer axial end (321), - a mounting 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 mounting hole (30) is offset by minus 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 hole (30) is tapped.

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

5. A set of offset crimp inserts (3) comprising a plurality of groups of offset crimp inserts (3), in which each group of inserts comprises offset crimp inserts (3) according to any 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 crimp insert (3) of one 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 any one of claims 1 to 4, in a crimped state, comprising its shaft (30) comprising a part housed (324) in the insert orifice (40) of the body (4) such that the central axis (y) of the shaft (30) is centered on the initial axis (Y) and a part crimped (320) against the body (4) extending between the axial end (321) of the shaft (30) and the part (324) in the insert orifice (40).

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

8. An element according to the preceding claim, wherein the body (4) comprises a first face (4a) and a second face (4b), the insert orifice (40) extends from the first face (4a) to the second face (4b), and wherein the first face (4a) comprises a first surface (41a) and a counterbore (43a) joining the insert orifice (40) to the first surface (41a), and the second face (4b) comprises a second surface (41b) and a counterbore (43b) joining the insert orifice (40) to the second surface (41b), the head (31) of the offset insert (3) being in the counterbore (43b) with its inner surface (310) in contact with a receiving surface (430) and its outer surface (311) flush with the second surface (41b) and the crimped portion (320) of the barrel (32) being in contact with the milling (43a).

9. A method for crimping an offset insert according to any one of claims 1 to 4 or according to the set of inserts according to claim 5, onto a body (4) comprising an insert orifice (40) opening cylindrically along an initial axis (Y) comprising the steps of: - Measuring a center distance (E) between the initial axis (Y) and a nominal axis (X), - Selecting 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) by a diameter of the shaft (32) of the selected offset insert (3), - Inserting the offset insert (3) with the adjustment axis (X) aligned on the nominal axis (X) in the insert orifice, - Crimping of the offset insert (3) on the body (4) forming together a piece.

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 shaft of the chosen offset insert into the cylindrical orifice, - A sub-step of pivoting the chosen offset insert (3), around its central axis (y) until the adjustment axis (x) is aligned with the nominal axis (X).

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