EP1439282A1 - Device for mounting an annular flask at a radial side of a rotor - Google Patents

Abstract

The device has a split annular retaining ring (44) arranged in an annular recess (16) delimited by walls, in which a wall (24) is formed by a flange face (26). A flange (36) has a festoon contour upper end with a recess (29). A base has a festoon contour front edge (62), and an annular groove formed between a notch and a rear flange (64). The groove holds the ring and allows an axial pin mount to penetrate the recess and gap.

Description

The invention relates to a device for retaining a flange annular against a radial face of a disc.

More particularly, the present invention relates to a device for retaining an annular flange against a radial face of a disc, this disc having in said radial face a recess annular delimited by several walls, one of which is formed by a face a flange which extends radially outwards, said flange having, in its radially inner part, an annular base in support against the radially outer wall of the recess and a foot which extends radially inward into the recess from the end axially internal of the base, said device comprising a ring of split ring retainer arranged in the recess.

Currently, among the different solutions available, there are that presented in FR 2 812 906: this solution uses a retainer provided with a rebate on its radially outer face in order to receive a portion of the foot. During disassembly, in order to allow the foot of the recess, a radial compression of the ring is carried out by means of a tool which is inserted into a notch in the end radially internal of the foot and which bears on the face radially outer ring so that it descends until the tool comes to rest on the upper end of the adjacent annular flange at the annular recess of the disc.

This solution is, however, liable to damage the radially inner end of the flange foot.

The present invention aims to provide a device to hold an annular flange against a radial face of a disc, allowing an assembly, as well as disassembly, simple and which does not risk damaging the flange, while not requiring the use of specific tools.

To this end, according to the present invention, so characteristic, said flange has an upper contoured end scalloped provided with at least one notch, said foot is provided in its radially internal part of a front edge, which has a contour scalloped in a complementary shape to the upper end of the flange, and a rear edge, said front and rear edges extending radially inward and delimiting between them an annular groove, said front edge being provided with at least one notch, said ring retainer present on its axially outer face at least one stud extending in axial direction and able to penetrate into said notch and in said notch, the rear edge of the flange foot and said tenon of the retaining ring have annular chamfers facing each other intended to allow the radial compression of the ring beforehand arranged in the recess during the axial sliding of the base in the recess during a first step of mounting the flange on the disc at the end of which the ring is retained axially in said groove, and the studs have a free end whose transverse width is greater than the transverse width of the notches so as to retain axially the flange against the flange during the rotation of the foot of the flange in the recess during a second step of mounting the flaccid on the disc.

In this way, we understand that it is possible to achieve securely blocking the flange in relation to the disc, towards axial and rotating.

Also, such an arrangement is easy to implement made use of the retaining ring which is the only piece which is stressed in compression, radial, during disassembly, the flange being subject to rotation, which will not damage the end radially internal to the foot of the flange.

Overall, thanks to the arrangement according to the present invention, and in particular due to the presence of the pin of the retaining ring, which is housed in the notch of the annular scalloped flange of the disc, it it is possible to disassemble and reassemble this device without special tool.

Preferably, the width in the axial direction of the section of the ring is substantially equal to the width in the axial direction of the groove.

This means that the axial distance between the rear face of the front face of the groove is provided to allow insertion therein, practically without play, the width in the axial direction of the section of the Ring.

Preferably, the length in the axial direction of the post is greater than the sum of the thickness in the axial direction of the front edge the foot of the flange and the thickness in the axial direction of the flange disc annulus.

In this way, the free end of the post protruding from the flange in the axial direction, disassembly by simple support on this free end of the post thus being facilitated.

According to a preferred arrangement, said post has a width substantially equal to the width of the notch of the front edge.

Such an arrangement makes it possible to avoid play between the sides of the tenon and the side walls of the notch, which therefore prevents impacts between these parts when the disc rotates, and therefore premature wear of the retaining ring and the flange.

According to another preferential arrangement, said post has a width substantially equal to the width of the notch of the flange.

This arrangement avoids play between the sides of the tenon and the side walls of the notch, which therefore prevents shocks between these parts when the disc rotates, and therefore wear the retaining ring and the disc.

According to a preferred embodiment, said front edge extends radially over a height greater than or equal to the thickness radial of the ring.

In this way, in fact, an axial support is produced between any the surface of the axially outer face of the retaining ring and the front face of the groove, this support on a maximum surface allowing minimize the stresses exerted in the axial direction on the retaining ring.

• la figure 1A est une vue partielle en projection d'un disque de rotor comportant, avant montage, un dispositif selon la présente invention,
• la figure 1B est une vue en coupe de la figure 1A selon la direction IB -IB,
• la figure 1C est une vue en coupe à plus grande échelle montrant plus en détail une partie de la figure 1B,
• la figure 1D est une vue depuis le dessus, en direction radiale, de la bague de retenue,
• les figures 2A et 2B sont des vues similaires à celles des figures 1A et 1B pendant une première étape de montage du flasque sur le disque,
• les figures 3A et 3B sont des vues similaires à celles des figures 1A et 1B pendant une deuxième étape de montage du flasque sur le disque, et
• les figures 4A, 4B et 4C sont des vues similaires à celles des figures 1A, 1B et 1C à la fin du montage.

Other advantages and characteristics of the invention will emerge on reading the following description given by way of example and with reference to the appended drawings in which:

• FIG. 1A is a partial view in projection of a rotor disc comprising, before mounting, a device according to the present invention,
• FIG. 1B is a sectional view of FIG. 1A in the direction IB -IB,
• FIG. 1C is a sectional view on a larger scale showing in more detail part of FIG. 1B,
• FIG. 1D is a view from above, in the radial direction, of the retaining ring,
• FIGS. 2A and 2B are views similar to those of FIGS. 1A and 1B during a first step of mounting the flange on the disc,
• FIGS. 3A and 3B are views similar to those of FIGS. 1A and 1B during a second step of mounting the flange on the disc, and
• Figures 4A, 4B and 4C are views similar to those of Figures 1A, 1B and 1C at the end of the assembly.

In the figures, and in particular in FIG. 1C, is visible a disc 10 of rotor of a gas turbine engine of axis of rotation 12.

This disc 10 has, at its radial face 14, a recess 16 delimited by a radially outer wall 18, a wall axially inner 20, a radially inner wall 22, and the face internal 24 of an annular flange 26 which extends radially outwards from the radially inner wall 22.

The upper end 28 of the annular flange 26 is radially distant from the radially outer wall 18 in order to provide a circular opening 30 allowing access into the recess 16.

Notches 29, having a U-shaped outline open on the upper end 28 of the annular flange 26, are made in the entire thickness of the annular flange 26 and are arranged at intervals regular along the entire flange 26. These notches 29 extend radially from the upper end 28 of the annular flange 26 up to a measurement allowing the introduction of an annular flange 36 as explained below.

The disc 10 has hollow portions at its periphery, such as axial notches, intended to receive blade roots 32 visible in Figures 1B, 2B, 3B and 4B. These blade feet are axially immobilized by the radially outer part 34 of the flange annular 36 whose radially inner part 38 has a base annular 40 which extends axially in the outer region of the recess 16 and a foot 42 which extends radially towards the axis of rotation 12 and axially towards the outside of the recess 16 from the end internal of the annular base 40.

The outside diameter of the annular base 40 is substantially equal to the diameter of the radially outer wall 18 of the recess 16 and the annular base 40 is slidingly pressing against this wall exterior 18.

The upper end 28 of the annular flange 26 has a scalloped contour formed, in a radial direction, of a regular alternation of hollows and protrusions forming a series of undulations as it appears in Figures 1A, 2A, 3A and 4A.

It should be noted that the notches 29 are located in the areas of the annular flange 26, the scalloped outline of which projects.

To allow the introduction of the annular base 40 of the foot 42 through the annular opening 30 in the recess 16, the distance separating the outside diameter of the annular base 40 of a hollow (of a projection) of the end face 68 of the front edge 62 is, on the one hand greater than the distance separating the radially outer wall 18 from a projection (of a hollow) of the upper end 28 of the flange 26, and on the other hand less than the distance between the radially outer wall 18 of the bottom of the notches 29 of the flange 26.

When the radially inner part 38 of the flange 36 is introduced into the recess 16, the flange 36 is immobilized radially relative to the disc 10 due to the fact that the annular base 40 is in abutment sliding against the radially outer wall 18.

The flange 36 is retained axially on the disc 10 by a split ring retainer 44.

The split annular retaining ring 44 has (see the 1C) an axially outer face 46, an axially face interior 48, a radially exterior face 50 connected to the face axially outer 46 and axially inner face 48, and finally a radially inner face 52.

The diameter of the radially inner face 52 is greater the diameter of the radially inner wall 22 of the recess 16, and less than the diameter of a projection of the upper end 28 of the flange 26, by a distance allowing the retraction of the retaining ring 44 behind the annular flange 26 by compression when the flange 36.

The split annular retaining ring 44 also has tenons 54 extending axially outward from the face axially outer 46, in the extension of the face radially outer 50 and radially inner face 52, with one end free 56 widened transversely to the axis of rotation 12.

The width, in transverse direction, of these tenons 54 allows their introduction, one by one into a corresponding notch 29, the enlarged end 56 of each tenon being retained axially by the annular flange 26 because this enlarged end 56 has a width, in transverse direction, greater than the width of the notches 29.

Indeed, the notches 29 are regularly distributed with a angular interval equal to that separating two consecutive studs 54 from the retaining ring 44.

The front face 58 of the enlarged end 56 of a tenon 54 is connected to the radially outer face 50 by a chamfer 60.

As can be seen more precisely in FIG. 1C, the foot 42 of the flange 36 has a radially internal end provided with a front annular rim 62 and a rear annular rim 64 between which is delimited an annular groove 66 of parallel axis of revolution to the axis of rotation 12.

The annular groove 66 has, in cross section, a U shape with the opening facing the axis of rotation 12.

The front annular rim 62 is delimited by a face end 68, a front face 70 of the annular groove 66 and a face front 72. The end face 68, turned towards the axis of rotation 12, connects the front face 70 of the annular groove 66 to the face 72 of the front annular rim 62.

The rear annular rim 64 is delimited by a face end 74, a rear face 76 of the annular groove 66 and a chamfer 78. The end face 74, turned towards the axis of rotation 12, connects the rear face 76 of the annular groove 66 to the chamfer 78 of the rear annular rim 64.

The chamfer 60 of the tenons 54 and the chamfer 78 of the flange rear annular 64 of foot 42 of annular flange 36 have angles identical with respect to the axis of rotation 12 of the disc 10, which are between 10 degrees and 45 degrees.

The annular groove 66 is therefore delimited by the front face 70, the rear face 76 and by an annular bottom wall 80 facing the axis of rotation 12.

In addition, it should be noted that the axially outer face 46 of the retaining ring 44 is intended to bear against the front face 70 of the annular groove 66.

Also, the axially inner face 48 of the ring of split annular retainer 44 is intended to come into abutment against the face rear 76 of annular groove 66.

Also, the radially outer face 50 of the retaining ring split annular 44 is intended to come into abutment against the bottom wall annular 80 of annular groove 66.

In its radially internal part of the front annular rim 62, the foot 42 of the flange 36 has a scalloped contour of shape complementary to the upper end 28 of the flange 26.

Indeed, as can be seen in FIGS. 1A, 2A, 3A and 4A, the end face 68 of the front edge 62 is formed, in the radial direction, regular alternation of hollows and projections forming a series undulations visible from outside the disc 10 (right side of the Figures 1B, 2B, 3B, 4B, 1C and 4C).

In the front annular rim 62 are made notches 82 regularly distributed with an angular interval equal to that separating two consecutive tenons 54 from the retaining ring 44.

These notches 82 are directed parallel to the axis of rotation 12 and have, in cross section, a U shape whose opening is turned towards the axis of rotation 12.

Also, these notches 82 are located at the location of the protrusions of the scalloped outline of the end face 68 of the front edge 62.

For reasons of ease of manufacture during machining, these notches 82 made in the front annular rim 62 are aligned with corresponding notches 82 ′ of the rear annular rim 64.

It can be noted that the width, in the axial direction parallel to the axis of rotation 12, of the cross section of the annular ring 44 is substantially equal to or barely less than the width in direction axial of the annular groove 66. This arrangement allows housing, without play or practically no play, of the annular ring 44 in the groove annular 66.

Also, we note that the length in the axial direction of the tenon 54, i.e. the distance separating the axially outer face 46 the retaining ring 44 of the front face 58 of the enlarged end 56, is greater than the sum of the thickness in the axial direction of the edge front 62 of the flange foot and the thickness in the axial direction of the annular flange 26 of the disc 10. In this way, in addition to the above provision, it is understood that the retaining ring 44 allows axially retain the annular flange 36 on the flange 26 of the disc 10.

According to an essential characteristic, in order to retain axially the flange against the disc 10, in the recess 16, the free end 56 tenons 54 is widened to reach a width in one direction transverse (perpendicular to the longitudinal axis 12 and to the direction radial) which is greater than the width, in transverse direction, of the notches 29.

In this way after mounting, the rear face of the end free 56 of the lugs 54 is in abutment against the external face 25 of the flange ring finger 26.

It should also be noted that each tenon 54 has a width, in a transverse direction perpendicular to the axis of rotation 12, substantially equal to or slightly less than the width, depending on the direction transverse, of a notch 82 of the front edge 62. In addition, each tenon 54 has a width, in the transverse direction, substantially equal to or slightly less than the width, depending on the transverse direction, a notch 29 in the flange 26.

In this way, each tenon 54, which is housed both in a notch 29 in the annular flange 26 and in a notch 82 in the rim front annular 62 of the foot 42 of the flange 36, performs the relative blocking in rotation between the flange 36 and the disc 10, without play or practically without Game.

In addition, the front edge 62 extends radially over a height greater than or equal to the radial thickness of the retaining ring 44: thus, a maximum contact surface is guaranteed therefore efforts minimum axial between the axially outer face 46 of the ring retainer 44 and the front edge of the flange 36, and more precisely the face before 70 of throat 66.

The different stages of mounting the flange 36 on the disc 10 will now be described in relation to FIGS. 1A to 4C.

The annular retaining ring 44 is enlarged then it is housed in the recess 16, the tenons 54 placed one by one in a notch 29 corresponding to the flange 26. The annular retaining ring 44 is places itself in visible rest position in Figures 1A to 1C when you stop exercising the radial force that keeps it apart.

In this position, the diameter of the face radially outer 50 of the split annular retaining ring 44 is greater than diameter of the protrusions of the scalloped outline forming the upper end 28 of the annular flange 26.

Also, in the situation visible in FIGS. 1A to 1C, the annular flange 26 therefore retains the retaining ring 44 axially since during a movement of axial displacement of the retaining ring 44 to the right of FIG. 1B or 1C, the internal face 24 of the flange 26 comes bearing against the axially outer face 46 of the retaining ring 44, and during a movement of axial displacement of the retaining ring 44 to the left of FIG. 1B or 1C, this is the external face 25 of the flange 26 which bears against the rear face of the enlarged end 56 studs 54.

This situation is, of course, due to the fact that the width, in transverse direction, from the free end 56 of the studs 54 is greater to the width, in transverse direction, of the notches 29

The flange 36 is then positioned so that the foot 42 is located opposite the annular opening 30 of the recess 16. The chamfer 78 of the rear edge 64 of the foot 42 then bears against the chamfer 60 of the pins 52 of the retaining ring 44. This position, visible on the FIGS. 1A to 1C center the retaining ring 44 relative to to the axis of rotation 12 of the disc 10.

The next step, visible in FIGS. 2A and 2B, consists in apply an axial force F on the annular flange, for example in its upper part, which leads to radial compression of the ring retainer 44 and an axial approximation of the annular base 40 of the flange 36 in the direction of the recess 16, and in particular in the direction of the wall axially inner 20 and the radially outer wall 18 of the recess 16.

It is understood that the radial compression of the ring of retainer 44 is due to the sliding between the chamfers 60 and 78.

During this approximation, the annular base 40 of the flange 36 slides against the radially outer wall 18 of the recess until it comes close enough to the axially inner wall 20 to reach in the position visible in FIGS. 3A and 3B in which the part upper part of the flange 36 bears against the radial face 14 of the disc 10 and foot 32 of the blades.

In this position illustrated in FIGS. 3A and 3B, the flange rear 64 then the front edge 62 having successively exceeded the flange 26 by entering the recess 16, one arrives at the situation where the ring retaining 44 is housed in the annular groove 66 and the flange annular front 62 is inserted between the retaining ring 44 and the annular flange 26.

Then, the retaining ring 44 is released while extending radially until it comes to rest against the bottom wall 80 of the groove annular 66 (Figures 4A, 4B and 4C).

The flange 36 is preferably mounted with a prestress axial on the disc 10.

As it appears in Figures 3A and 3B, we exercise also a rotation (arrow R) of the flange 36 relative to the disc to arrive at the situation after mounting visible in FIGS. 4A, 4B and 4C. The notches 82 of the front edge 62 coming to be placed above the hold 54, this allows the retaining ring 44 to loosen in extending radially until it comes to bear against the bottom wall 80 of the annular groove 66.

In this situation, the pins 54 of the retaining ring 44 serve as a key between the flange 36 and the flange 26 of the disc 10 which are interconnected with a system similar to a bayonet connection, by interlocking and rotation.

Indeed, the flange 36 is blocked relative to the disc 10, on the one hand axially by the support of the front face 72 of the front edge 62 against the internal face 24 of the scalloped annular flange 26 which only intervenes after the second assembly step in which the flange 36 is rotated relative to disc 10 by an angle such than that forming the angular interval between the hollows (or protrusions) of the upper end 28 of the annular flange 36 or of the end face 68 of the front edge 62.

On the other hand, the flange 36 is locked in rotation relative to the disc 10 due to tenons 54 housed in the notches 29 of the flange 26 and in the notches 82 of the front edge 62.

To easily carry out the disassembly between the flange 36 and the disc 10, it is necessary to perform the above operations in reverse order. Thus, this disassembly is carried out by a first operation consisting of a simple rotation of the flange 36 (in the opposite direction to that of arrow R in FIGS. 3A and 3B) and by a second operation consisting of a support on the chamfer 60 to axially compress the ring 44 and allow the flange 36 to be released.

In this way, we understand that we can do without specific tools during assembly and disassembly of the flange, the disc is not otherwise requested in these stages of mounting and dismantling so that it is not used outside the periods of thus increasing its service life.

Claims (6)

Device for retaining an annular flange (36) against a radial face (14) of a disc (10), this disc (10) having in said radial face (14) an annular recess (16) delimited by several walls (18, 20, 22, 24) one of which (24) is formed by one face of a flange (26) which extends radially outwards, said flange (36) having, in its radially inner part, a base annular (40) bearing against the radially outer wall (18) of the recess (16) and a foot (42) which extends radially inwards into the recess (16) from the end axially internal of the base (40), said device comprising a split annular retaining ring (44) disposed in the recess (16), characterized in that said flange (26) has an upper end (28) of scalloped outline provided with at least one notch (29), in that said foot (42) is provided in its radially inner part of a front edge (62), which pr feels a scalloped contour of complementary shape of the upper end (28) of the flange (26), and of a rear edge (64), said front and rear edges (62, 64) extending radially inwards and delimiting between them an annular groove (66), said front edge (62) being provided with at least one notch (82), in that said retaining ring (44) has on its axially outer face (50) at least a tenon (54) extending in an axial direction and capable of penetrating into said notch (29) and into said notch (82), in that the rear edge (64) of the foot (42) of the flange (36) and said tenon (54) of the retaining ring (44) have annular chamfers (60, 78) facing each other intended to allow the radial compression of the ring (44) previously disposed in the recess (16) during of the axial sliding of the base (40) in the recess (16) during a first step of mounting the flange (36) on the disc (10) at the end of the which the ring (44) is retained axially in said groove (66), and in that the pins (54) have a free end (56) whose transverse width is greater than the transverse width of the notches (29) so as to axially retain the flange (36) against the flange (26) during the rotation of the foot (42) of the flange (36) in the recess (16) during a second step of mounting the flange (36) on the disc (10). Device according to claim 1, characterized in that the width in the axial direction of the section of the ring (44) is substantially equal to the width in the axial direction of the groove (66). Device according to any one of the preceding claims, characterized in that the length in the axial direction of the tenon (54) is greater than the sum of the thickness in the axial direction of the front edge (62) of the foot (42) of the flange ( 36) and the thickness in the axial direction of the annular flange (26) of the disc (10). Device according to any one of the preceding claims, characterized in that the said pin (54) has a width substantially equal to the width of the notch (82) of the front edge (62). Device according to any one of the preceding claims, characterized in that the said pin (54) has a width substantially equal to the width of the notch (29) of the flange (26). Device according to any one of the preceding claims, characterized in that said front edge (62) extends radially over a height greater than or equal to the radial thickness of the ring (44).

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