EP1439282B1 - Device for mounting an annular flask at a radial side of a rotor - Google Patents

Description

The invention relates to an assembly for retaining an annular flange against a radial face of a disc, said assembly comprising a disc, an annular flange and a split annular retaining ring.

More particularly, the present invention relates to an assembly for retaining an annular flange against a radial face of a disk, this disk having in said radial face an annular recess delimited by a plurality of walls, one of which is formed by a face of a flange. which extends radially outwards, said flange having, in its radially inner portion, an annular base bearing against the radially outer wall of the recess and a foot which extends radially inwards in the recess. from the axially inner end of the base, said split annular retaining ring being disposed in the recess and the foot of the flange and the retaining ring having annular chamfers vis-à-vis.

Currently, among the various solutions available, there is that presented in FR 2 812 906: this solution uses a retaining ring provided with a rabbet on its radially outer face to receive a portion of the foot. During disassembly, in order to let the foot out of the recess, radial compression of the ring is carried out by means of a tool which is inserted into a notch in the radially inner end of the foot and which bears on the face radially outer of the ring so as to lower it until the tool bears on the upper end of the annular flange adjacent to the annular recess of the disk.

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

The present invention aims to provide a device for retaining an annular flange against a radial face of a disk, allowing a mounting, and a disassembly, simple and which does not risk damaging the flange, while not requiring the use of specific tools.

For this purpose, according to the present invention, typically said flange has an upper end of scalloped contour provided with at least one notch, said foot is provided in its radially inner portion with a front flange, which has a scalloped contour of complementary shape of the upper end of the flange, and a rear flange, said front and rear flanges extending radially inwardly and delimiting between them an annular groove, said front flange being provided with at least one notch, said retaining ring has on its axially outer face at least one tenon extending axially and able to penetrate into the groove. said notch and in said notch. Annular chamfers facing each other are arranged on the rear flange of the flange foot and on the tenon of the retaining ring and are intended to allow the radial compression of the ring previously arranged in the recess during sliding. axial 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 tenons have a free end whose transverse width is greater than the transverse width of the notches so as to axially retain the flange against the flange during the rotation of the foot of the flange in the recess during a second step of mounting the flange on the disc.

In this way, it is understood that it is possible to securely secure the blocking of the flange relative to the disk, in the axial direction and in rotation.

Also, such an arrangement is easy to implement because of the use of the retaining ring which is the only part which is stressed in compression, radial, during disassembly, the flange being subjected to only one rotation , which does not risk damaging the radially inner end of the flange foot.

Overall, thanks to the arrangement according to the present invention, and in particular because of the presence of the tenon of the retaining ring, which is housed in the notch of the annular scalloped flange of the disc, it is possible to perform the disassembly and reassembling this device without special tools.

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 separating the rear face of the front face of the groove is intended to allow to insert, virtually without play, the width in the axial direction of the section of the ring.

Preferably, the length in the axial direction of the pin is greater than the sum of the axial thickness of the front flange of the flange foot and the axial thickness of the annular flange of the disc.

In this way, it is easy to access the free end of the pin protruding from the flange in the axial direction, disassembly by simply pressing on this free end of the pin being thus 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 thus avoids shocks between these parts during the rotation of the disc, and therefore premature wear of the retaining ring and flange.

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

This arrangement makes it possible to avoid play between the sides of the post and the side walls of the notch, which thus avoids shocks between these parts during the rotation of the disc, and therefore premature wear of the retaining ring and the disk.

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

In this way, in fact, an axial bearing is made between the entire surface of the axially outer face of the retaining ring and the front face of the groove, this bearing on a maximum surface making it possible to reduce as much as possible the stresses exerted in the direction axial 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 become apparent 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 disk comprising, before assembly, 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 greater detail a 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 stage of mounting the flange on the disc,
• FIGS. 3A and 3B are views similar to those of FIGS. 1A and 1B during a second stage 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 rotor disc 10 of a gas turbine engine having a rotation axis 12.

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

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

The disc 10 has at its periphery recessed portions, such as axial notches, for receiving blade roots 32 visible in Figures 1B, 2B, 3B and 4B. These blade roots are immobilized axially by the radially outer portion 34 of the annular flange 36 whose radially inner portion 38 comprises 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 outwardly of the recess 16 from the inner end of the annular base 40.

The outer 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 bears against this outer wall 18.

The upper end 28 of the annular flange 26 has a scalloped contour formed in a radial direction with a regular alternation of depressions and projections forming a series of corrugations as shown in FIGS. 1A, 2A, 3A and 4A.

It should be noted that the notches 29 are located in the areas of the annular flange 26 whose scalloped contour is projecting.

In order 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 outer diameter of the annular base 40 from a recess (of a projection) of the face end 68 of the front flange 62 is, on the one hand, greater than the distance separating the radially outer wall 18 from a protrusion (of a hollow) of the upper end 28 of the flange 26, and secondly less than the distance separating the radially outer wall 18 from the bottom of the notches 29 of the flange 26.

When the radially inner portion 38 of the flange 36 is introduced into the recess 16, the flange 36 is immobilized radially relative to the disc 10 because the annular base 40 bears against the radially outer wall 18.

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

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

The diameter of the radially inner face 52 is greater than 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, a distance allowing the retraction of the retaining ring 44 behind the annular flange 26 by compression during the introduction of the flange 36.

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

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

Indeed, the notches 29 are regularly distributed with an angular interval equal to that separating two consecutive pins 54 of the retaining ring 44.

The end face 58 of the widened end 56 of a peg 54 is connected to the radially outer face 50 by a chamfer 60.

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

The annular groove 66 has, in cross section, a U-shape whose opening is turned towards the axis of rotation 12.

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

The rear annular flange 64 is delimited by an end face 74, a rear face 76 of the annular groove 66 and a 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 flange 64.

The chamfer 60 of the pins 54 and the chamfer 78 of the rear annular flange 64 of the foot 42 of the annular flange 36 have identical angles 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 split annular retaining ring 44 is intended to bear against the rear face 76 of the annular groove 66.

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

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

Indeed, as it is visible in Figures 1A, 2A, 3A and 4A, the end face 68 of the front flange 62 is formed, in the radial direction, a regular alternation of recesses and projections forming a series of ripples visible from outside the disk 10 (right side of Figures 1B, 2B, 3B, 4B, 1C and 4C).

In the front annular flange 62 are provided notches 82 regularly distributed with an angular interval equal to that separating two studs 54 consecutive retaining ring 44.

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

Also, these notches 82 are located at the location of the projections of the scalloped contour of the end face 68 of the front flange 62.

For reasons of ease of manufacture during machining, these notches 82 made in the front annular flange 62 are aligned with corresponding notches 82 'of the rear annular flange 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 only slightly less than the width in the axial direction of the annular groove 66. the housing, without play or virtually without clearance, of the annular ring 44 in the annular groove 66.

Also, it is noted that the length in the axial direction of the pin 54, that is to say the distance separating the axially outer face 46 of the retaining ring 44 of the end face 58 of the widened end 56, is greater than the sum the thickness in the axial direction of the front flange 62 of the flange foot and the axial thickness of the annular flange 26 of the disc 10. In this way, in addition to the aforesaid arrangement, it is understood that the retaining ring 44 allows axially retaining the annular flange 36 on the flange 26 of the disc 10.

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

In this way after assembly, the rear face of the free end 56 of the tenons 54 bears against the outer face 25 of the annular flange 26.

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

In this way, each post 54, which is housed both in a notch 29 of the annular flange 26 and in a notch 82 of the flange front annulus 62 of the foot 42 of the flange 36, realizes the relative locking in rotation between the flange 36 and the disk 10, without play or virtually without play.

In addition, the front flange 62 extends radially over a height greater than or equal to the radial thickness of the retaining ring 44: thus, it ensures a maximum contact area and therefore minimum axial forces between the axially outer face 46 of the retaining ring 44 and the front flange of the flange 36, and more precisely the front face 70 of the groove 66.

The various phases of mounting the flange 36 on the disc 10 will now be described in connection with Figures 1A to 4C.

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

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

Also, in the situation visible in FIGS. 1A to 1C, the annular flange 26 thus retains the retaining ring 44 axially since, during an axial displacement movement of the retaining ring 44 to the right of FIG. 1B or 1C, the inner face 24 of the flange 26 bears against the axially outer face 46 of the retaining ring 44, and during an axial displacement movement of the retaining ring 44 towards the left of FIG. 1B or 1C, c 'is the outer face 25 of the flange 26 which abuts against the rear face of the widened end 56 of the studs 54.

This situation is, of course, due to the fact that the width in the transverse direction of the free end 56 of the tenons 54 is greater than 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 flange 64 of the foot 42 then bears against the chamfer 60 pins 52 of the retaining ring 44. This position, visible in FIGS. 1A to 1C, carries out the centering of the retaining ring 44 with respect to the axis of rotation 12 of the disk 10.

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

It is understood that the radial compression of the retaining ring 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 the position shown in FIGS. 3A and 3B in FIG. which the upper portion of the flange 36 bears against the radial face 14 of the disc 10 and the root 32 of the blades.

In this position illustrated in Figures 3A and 3B, the rear flange 64 and the leading edge 62 having successively exceeded the flange 26 into the recess 16, we arrive at the situation where the retaining ring 44 is housed in the annular groove 66 and the front annular flange 62 is interposed between the retaining ring 44 and the annular flange 26.

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

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

As it appears in FIGS. 3A and 3B, a rotation (arrow R) of the flange 36 with respect to the disk is also carried out to arrive at the situation after visible mounting in FIGS. 4A, 4B and 4C. The notches 82 of the leading edge 62 being placed above the tenons 54, this allows the retaining ring 44 to relax in extending radially until it bears against the bottom wall 80 of the annular groove 66.

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

Indeed, the flange 36 is locked with respect to the disc 10, on the one hand axially by the support of the front face 72 of the front flange 62 against the inner face 24 of the scalloped annular flange 26 which comes into play only after the second mounting step in which the flange 36 is rotated relative to the disk 10 by an angle such as that forming the angular interval between the recesses (or projections) of the upper end 28 of the annular flange 36 or of the end face 68 of the front flange 62.

On the other hand, the flange 36 is locked in rotation with respect to the disc 10 because of the studs 54 housed in the notches 29 of the flange 26 and in the notches 82 of the front flange 62.

For easy disassembly between the flange 36 and the disk 10, it is necessary to perform the above operations in the 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 the arrow R of FIGS. 3A and 3B) and by a second operation consisting of a bearing on the chamfer 60 for axially compressing the ring 44 and allowing the release of the flange 36.

In this way, it is understood that we can do without specific tools during assembly and disassembly of the flange, the disk is also not requested in these steps of assembly and disassembly so that it does not is not requested outside the operating periods and thus increases its service life.

Claims (6)

1. An assembly for retaining an annular plate (36) against a radial face (14) of a disk (10), said assembly including a disk (10), an annular plate (36) and a split annular retaining ring (44), the disk (10) presenting in said radial face (14) an annular recess (16) defined by a plurality of walls (18, 20, 22, 24) one of which (24) is formed by a face of a flange (26) which extends radially outwards, said plate (36) presenting in its radially inner portion an annular base (40) pressing against the radially outer wall (18) of the recess (16) and a root (42) extending radially towards the inside of the recess (16) from the axially inner end of the base (40), said split annular retaining ring (44) being disposed in the recess (16), the root (42) of the plate (36) and the retaining ring (44) including facing annular chamfers (60, 78), said assembly being characterized in that said flange (26) presents a top end (28) of crenellated outline provided with at least one notch (29), in that said root (42) is provided in its radially inner portion with a front rim (62) which presents a crenellated outline of shape complementary to the top end (28) of the flange (26), and a rear rim (64), said front and rear rims (62, 64) extending radially inwards and defining between them an annular groove (66), said front rim (62) being provided with at least one mortice (82), in that said retaining ring (44) presents on its axially outer face (50) at least one tenon (54) extending in an axial direction and suitable for penetrating in said notch (29) and in said mortice (82), in that said facing annular chamfers (60, 78) are disposed on the rear rim (64) of the root (42) of the plate (36) and on said tenon (54) of the retaining ring (44) and are designed to enable the ring (44) previously disposed in the recess (16) to be compressed radially during axial sliding of the base (40) into the recess (16) during an initial step of mounting the plate (36) on the disk (10), at the end of which step the ring (44) is retained axially in said groove (66), and in that the tenons (54) present respective free ends (56) of transverse width greater than the transverse width of the notches (29) so as to retain the plate (36) axially against the flange (26) when the root (42) of the plate (36) is turned in the recess (16) during a second step of mounting the plate (36) on the disk (10).
2. An assembly according to claim 1, characterized in that the width of the section of the ring (44) in the axial direction is substantially equal to the width of the groove (66) in the axial direction.
3. An assembly according to any one of the preceding claims, characterized in that the length of the tenon (54) in the axial direction is greater than the sum of the thickness in the axial direction of the front rim (62) of the root (42) of the plate (36) plus the thickness in the axial direction of the annular flange (26) of the disk (10).
4. An assembly according to any one of the preceding claims, characterized in that said tenon (54) presents a width that is substantially equal to the width of the mortise (82) of the front rim (62).
5. An assembly according to any one of the preceding claims, characterized in that said tenon (54) presents a width substantially equal to the width of the notch (29) of the flange (26).
6. An assembly according to any one of the preceding claims, characterized in that said front rim (62) extends radially over a height that is greater than or equal to the radial thickness of the ring (44).

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