EP3265654B1 - Bladed integrated disk comprising a shortened hub and a supporting element - Google Patents

Description

TECHNICAL AREA

The invention relates to a fan disk of a turbojet type engine, the disk being of the blisk type, that is to say that it comprises a hub and blades forming a single piece indissociable.

STATE OF THE PRIOR ART

A turbojet type engine with a double flow 1 such as that of the figure 1 , comprises an inlet sleeve 2 in which the air is admitted before being sucked by the blades of a fan 3. After passing the region of the fan, the air is divided into a central primary flow and a secondary flow that surrounds the primary flow.

The primary air flow then passes through a low pressure compressor 4 located immediately after the fan 3 while the secondary flow is propelled backwards to directly generate additional thrust by being blown around the primary flow.

The primary flow then passes through a high-pressure compressor 6, before reaching a chamber 7 where its combustion takes place after injection and vaporization of a fuel. After combustion, this primary flow is expanded in a high pressure turbine 8 and then in a low pressure turbine to drive in rotation the compression stages and the fan, before being expelled to the rear of the engine to generate thrust.

Each turbine and each compressor comprises a succession of stages each comprising a series of blades oriented radially and regularly spaced around a rotation shaft of the engine. This central shaft or rotor which extends along a longitudinal axis AX carries the rotary elements of the turbine as well as the rotary elements of the compressor and the fan.

The blades of the blower may be elements attached to a disk, called a fan disk which is first fixed for example by splined connection to the motor shaft. After fixing the disk, the vanes are engaged by the front of the disk by being engaged in longitudinal grooves formed at the periphery of the disk and which are called cells.

In the case of a bladed disc blower monobloc, the series of blades of the blower is carried by a hub forming with it a single piece and inseparable. A portion of such a blisk, corresponding to an angular sector about the axis AX, is shown schematically in FIG. figure 2 . Another example of a blisk is disclosed in the document US3501090 .

The object of the invention is to propose a new blisk structure.

STATEMENT OF THE INVENTION

For this purpose, the subject of the invention is a turbine blower disk for a turbomachine such as a turbojet engine, this blisk comprising a hub delimited by an upstream face and a downstream face with respect to the flow through the bladed disk in service, and an outer peripheral face and an internal peripheral face of revolution delimiting an internal opening of the hub, this hub bearing at its outer peripheral face of the blades, each blade having a leading edge and a trailing edge, the hub and the blades constituting a one-piece assembly, in which the upstream face and / or the downstream face is offset while being situated along the axis of rotation between the leading edges and the trailing edges of the blades, the bladed disk comprising an element filling element attached to the offset face, this filling member comprising an inner centering ferrule engaging in the inner opening of the hub, a radial portion pressing against the facing side and an outer ferrule extending in the extension of the outer peripheral face of the hub to extend this outer peripheral face.

With this arrangement, the disk comprises a hub dedicated to the maintenance of blades being optimized to maximize the mechanical strength of these blades, and it is an added filling member which extends the cylindrical outer face of the hub into being dedicated to the guiding of the air vein having crossed the blades. The shape and the material of the hub can thus be optimized specifically with respect to the mechanical strength of the blades, and the filling member can be made of another material and with another dimensioning to present in particular a reduced mass.

The subject of the invention is also a disk thus defined, in which the radial portion of the filling member comprises a series of radial segments spaced apart from each other, in which the remote face comprises, at its inner periphery, spurs protruding axially to extend the inner peripheral face, each radial segment of the radial portion engaging between two spurs, each spur having an inner groove to jointly define a discontinuous circumferential inner groove, and a locking ring engaging in said circumferential inner groove to block the filling member in position along the axis of rotation, the member being blocked between on the one hand the offset face against which its radial portion bears and on the other hand the ring against which is in support one edge of the centering shell.

The subject of the invention is also a disc thus defined, comprising at least one locking latch in rotation of the filling member, this latch being positioned between two consecutive spurs joining them together, this latch comprising a groove extending in the continuity of the grooves of the two spurs between which it is mounted to receive a corresponding portion of the locking ring, this latch having a locking face bearing against the offset face of the hub when the latch is in place, this locking face having a groove radial in which engages a portion of the radial segment located between the two spurs that this lock joins, to lock in rotation the filling member, the radial segment comprising at the latch a recess in which the lock engages to lock this lock radially.

The subject of the invention is also a disc thus defined, in which each blade has on the side of its leading edge or its trailing edge an extension towards the axis of rotation through which it is connected to the offset face of the hub. , and wherein the outer ferrule comprises a series of festoons or notches in which engages each blade extension when the filling member is in place.

The invention also relates to a disk thus defined, having a seal along an edge of the outer ring to provide a seal between the outer ring and the hub with the blades that carries the hub.

The invention also relates to a disc thus defined, wherein it is the upstream face of the hub which is offset and equipped with the filling member.

The invention also relates to a disc thus defined, wherein it is the downstream face of the hub which is offset and equipped with the filling member.

The invention also relates to a turbomachine fan comprising a disk thus defined.

The invention also relates to a turbojet engine, comprising a bladed disk thus defined.

BRIEF DESCRIPTION OF THE DRAWINGS

• The figure 1 is an overview of a turbojet engine shown in longitudinal section;
• The figure 2 is a partial perspective view of a one-piece bladed disk according to the state of the art showing an angular sector of this one-piece disc comprising two blades;
• The figure 3 is a partial side sectional view of a monobloc blisk equipped with a filling member according to the invention;
• The figure 4 is a partial view of the outer shell of the filler member equipping the blisk in accordance with the invention;
• The figure 5 is a partial view in developed of the downstream face of the bladed disk equipped with the filling device according to the invention;
• The figure 6 is a partial view in longitudinal section of the bladed disc at a spur for fixing the filling member according to the invention;
• The figure 7 is a partial view in longitudinal section of the bladed disc at a locking bolt of the filling member according to the invention;
• The figure 8 is a partial view in longitudinal section of the bladed disc at a radial segment of the radial portion of the filling member according to the invention.

DETAILED PRESENTATION OF PARTICULAR EMBODIMENTS

The blisk according to the invention which is partially represented in figure 3 11 is marked with a hub or rim 12 corresponding to its central portion, and which carries a series of blades, one of which appears in the figure 3 identified by 13.

The hub 12 which has a generally annular shape extending around its axis of rotation AX, forms a whole with the blades that it carries, that is to say a single piece piece resulting from the same manufacturing process .

This hub 12 has a frustoconical outer peripheral face 14 around the axis AX and from which the bases of each of the vanes which are spaced from each other around the axis AX start. This hub 12 also has a through internal opening delimited by an inner face 15 of revolution which is here cylindrical.

The outer peripheral face 14 extends radially upstream towards the axis AX in an upstream face 16 in the form of a flat ring, and it extends downstream radially towards the axis AX in a downstream face 17 also in the form of a flat ring. The upstream and downstream faces in the form of crowns are centered on the axis AX and oriented perpendicularly to this axis.

Each blade has a leading edge 18 and a trailing edge 19, the leading edges being those upstream to face the incident airflow, while the trailing edges are downstream of the leading edges. relative to the flow of air passing through the reactor in operation.

The hub 12 is hollowed out at its downstream portion, so that the downstream face 21 is offset along the axis AX towards the central region, with respect to the edges of the 19 leaking blades. This remote face is thus located along the axis AX between the leading edges 18 and the trailing edges 19 of the blades. Each blade 13 is connected by its base to the outer peripheral surface 14 which is thus shorter than the blades along the axis AX. The distance between the upstream face 16 and the downstream face 17 is thus less than the length of the blades projected on the axis AX, also called rope.

The trailing edge portion 19 which is in the vicinity of the base of each blade 13 is thus located, along the axis AX, beyond the downstream face 17 of the hub 12. In addition, each trailing edge 19 is extended radially towards the axis AX, below the peripheral face 14, so as to extend the downstream portion of pale towards the downstream face 17.

These extensions of the downstream portions of the blades 13 towards the axis AX are represented in the figure 3 being identified by 20. They allow in particular to avoid the formation of zones of stress concentration.

To fill the recess of the rear portion of the hub 12, the blisk 11 according to the invention is equipped with a filling member 21 pressed against the downstream face 17 and whose outer face extends in the extension of the face 14 of the hub 12 to extend this frustoconical face 14 to the level of the trailing edges 19 of the blades 13 or beyond.

This filling member 21 comprises an inner ferrule 22 of centering, this ferrule 22 having an edge extending by a radial portion 23 along the downstream face 17 to the peripheral face 14, and extending therein a frustoconical outer ferrule 24 .

When the filling member is in place, as in the figures, the inner centering ring 22 is engaged in the cylindrical inner portion of the hub 12, along the inner face 15, to center the filling member with respect to the hub . The frustoconical outer shell 24 is then positioned so that its outer face 26 forms a continuation of the outer face 14 of the hub 12.

In operation, the flow of air or vein passing through the blades 13 is thus delimited internally during its displacement, firstly by the frustoconical outer face 14 of the hub body 12 and then by the outer face 26 of the outer shell of the filling device. These two frustoconical external faces 14, 26 extend in the extension of one another to form a continuous outer surface defining the vein passing through the blades.

As visible on the figure 4 , the outer shell 24 has at its upstream edge a series of festoons or notches, marked by 27, which each correspond to one of the blades 13. Each notch 27 is intended to surround an extension 20 of a blade 13 extending below the level of the cylindrical face 14, so that the outer shell 24 can have its outer face 26 at the same level as the face 14 it extends.

The fitting of the filling member 21 thus consists of engaging it from the rear of the hub 12 to press its portion 23 against the downstream face 17, while slightly pivoting it about the axis AX so as to engage the extensions 20 of the blades 13 which are inclined with respect to the axis AX, in the slots or notches 27.

Complementarily, a not shown seal is provided to be interposed between the edge of the outer shell 24, and the blades 13 or their lower extensions 20 and the downstream face 17, to prevent the passage of gas between the ferrule external 24 and the hub 12.

It may be a single globally circumferential joint that runs along the entire upstream edge of the outer shell by following the scalloped shape of this upstream edge, or a series of unitary joints each extending over a region corresponding to a festoon 27 of the outer shell 24.

The seal or the series of seals ensuring the seal between the hub 12 and the outer ferrule make it possible to fill a functional clearance which is provided between these parts so that the blades have a certain mobility in flexion when they are mechanically stressed. As an order of magnitude, the functional clearance filled by the seal has a thickness of between half and twice the blade thickness in the region where it is surrounded by the festoon.

The material of the seal may be chosen elastic or viscoelastic to participate in the dissipation of the energy absorbed by the blades. In the case of a viscoelastic material it will be possible to choose a rubber, a silicone or a polymer elastomer or epoxy resin, which may be monolayer or multilayer having layers that may be made of different materials.

In general, the seal constitutes the rounded or curved cross section connection portion which joins the blade with the outer ferrule and the downstream face.

As illustrated schematically on Figures 5 to 8 , the filling member 21 has its inner ferrule 22 which is centered on the inner face 15 of the hub 12 while being supported at the level of spurs 28 which protrude from the downstream face 17 to constitute extensions of the internal face 15. The spurs 28 are regularly spaced from each other about the axis AX, each spur 28 being located in line with a corresponding blade 13.

Complementarily, each spur 28 has a groove 29 extending in a plane normal to the axis AX and opening in the inner face 15 to the axis AX. The grooves 29 of the different spurs 28 thus jointly define a discontinuous internal groove adapted to receive an inner circumferential ring marked 31 in the figures. The outer edge of this ring is engaged in these grooves 29 to lock in position while its inner edge protrudes inwardly so as to constitute a stopper protruding from the inner face 15 and against which bears the centering ferrule 22.

Complementarily, the ring 31 has ends 32, 33 bent radially outwardly, each of which locks against a corresponding face of a spur 28, in order to prevent rotation of this ring 31 about the axis AX by compared to the hub 12. As seen in the figure 5 , the ends of the rod are slightly spaced, so that they are supported on the faces of two contiguous spurs.

This ring 31 thus makes it possible to block the filling member 21 along the axis AX, the spurs 28 passing through openings in the radial portion 23 of the filling member to receive the ring at their radially inner faces. Concretely, the member 21 is held axially on the one hand by the face 17 against which its radial portion 23 is supported, and on the other hand by the ring 31 against which is in support of the inner ferrule 22, which makes it possible to immobilize it in both directions along the axis AX.

The filling member is also locked in rotation about the axis AX, relative to the hub 12 to which it is rigidly secured.

More particularly, the radial portion 23 of the member 21 is formed of several radial segments 34 regularly spaced about the axis AX, and which define the openings through which the spurs when the filling member is in place. Each radial segment has an inner end connected to the inner ferrule 22 and an outer end connected to the outer ferrule 24.

The number of radial segments 34 is identical to the number of spurs 28, so that each radial segment 34 runs along the downstream face 17 of the hub 12, extending between two consecutive spurs 28 protruding from this downstream face 17.

Two of the radial segments 34 of the rigid assembly constituted by the filling member 21 are locked by two latches located at 180 ° relative to each other about the axis AX. Advantageously, it will be possible to select bolt holes at 120 °, or else four locks at 90 °. It is still possible to provide a single latch with a mass reported at 180 °, so as to provide an appropriate balance.

One of these locks appears in the Figures 5, 7 and 8 by being marked by 36. It has a shape close to that of each spur 28 protruding from the face 17, and its outer dimensions are such that it fits between two consecutive spurs 28, so that it combines these two elements to form with them a continuous set.

Like each spur 28, this latch 36 has a lower face extending in the continuity of the inner surface 15 when it is in place, and it comprises a groove 37 opening into this inner face and extending perpendicularly to the axis. AX when the lock is in place. The groove 37 of the lock 36 extends in the continuity of the grooves 29 of the spurs between which the lock 36 is installed, this groove 37 also receiving the rod 31 when the assembly is in place.

This latch 36 comprises a locking face which bears against the face 17 of the hub 12, this locking face comprising a groove extending radially with respect to the axis AX when the latch 36 is in place, this groove being dimensioned to receive a radial segment 34.

Complementarily to the groove of the lock 36, the radial segment 34 which engages in this groove has a recess 38 at this latch 36, wherein the latch 36 fits to be blocked radially when the assembly is in place.

As visible on the figure 8 , the recess 38 of the radial segment 34 which blocks the latch 36 corresponds to a reduction in the thickness of this radial segment, measured parallel to the axis AX.

Thus, when the latch 36 is in place while being engaged between two consecutive spurs, the radial segment 34 is engaged in the groove of the latch to lock the filling member in rotation relative to the hub 12, and the latch 36 is fitted into the recess 38 of the radial segment to be radially blocked. Complementarily, and as will be understood, the ring is then engaged in the groove 37 of the lock to block it so that it can not move parallel to the axis AX.

The assembly of the assembly consists in the first place to set up the filling member 21 against the downstream face 17 of the hub, while engaging the centering ferrule 22 in the hub. The two locking latches can then be put in place, each between two consecutive spurs, to be diametrically opposed to the axis AX. The establishment of a lock 36 is to position it vis-à-vis the space between the two consecutive spurs between which it must be installed, and move it parallel to the axis AX to nest on a portion of the radial segment 34 located between these two consecutive spurs.

Once the locks have been put in place, the locking rod 31 can be installed by being engaged in the internal groove delimited by the grooves of the spurs and locks, to lock in position the filling member relative to the hub.

The filling member according to the invention offers a satisfactory resistance to centrifugal stresses because it is a single piece of revolution extending around the axis AX.

Thanks to its centering on the hub via the inner shell, and its support on the downstream face of the hub, the filling member is positioned accurately relative to the blisk disk body, so that the outer face of the ferrule external extends precisely in the extension of the frustoconical outer face of the hub.

The retaining spurs of the ring are elements that protrude from the hub, which avoids making recesses in the hub that could generate as many areas of stress concentrations.

Thanks to the functional clearance provided between the hub with the blades it carries and the outer shell, the blades retain at their rear portions the flexibility required to withstand the various operating constraints.

In particular, the bottom of the trailing edge of the blades to their nearest portions of the axis AX is released thanks to the functional play for the benefit of the flexibility required during a solicitation in case of impact of bird against the blades . The filling member promotes the possibility of deformation of the blades under this effort.

Moreover, in the example of the figures, the invention is applied to a hub comprising a downstream face which is offset, but it also applies to a hub whose upstream face is offset, the filling member being then fitted against the upstream face of the hub so as to extend the peripheral face of the hub upstream.

Claims (9)

1. Fan blisk (11) for a turbomachine such as a turbojet, this blisk (11) comprising a hub (12) delimited by an upstream face (16) and a downstream face (17) relative to the flow passing through the blisk in service and an external peripheral face (14) and an internal peripheral face (15) of revolution delimiting an internal opening in the hub (12), this hub (12) carrying blades (13) on its external peripheral face (14), each blade (13) having a leading edge (18) and a trailing edge (19), the hub (12) and the blades (13) forming a one-piece assembly, wherein the upstream face (16) and/or the downstream face (17) is offset, being located along the axis of rotation (AX) between the leading edges (18) and the trailing edges (19) of the blades (13), characterized in that the blisk (11) comprises a filling member (21) mounted on the offset face, said filling member (21) comprising an inner centring ferrule (22) engaging in the inner opening (15) of the hub, a radial portion (23) resting against the offset face and an outer ferrule (24) extending in continuity with the outer peripheral face (14) of the hub to prolong this outer peripheral face.
2. Disk according to claim 1, wherein the radial portion (23) of the filling member (21) comprises a series of radial segments (34) at a spacing from each other, wherein the offset face (17) comprises spurs (28) on its inner periphery that project in the axial direction to prolong the inner peripheral face (15), each radial segment (34) of the radial portion (23) engaging between two spurs (28), each spur (28) being provided with an inner groove (29) to conjointly delimit a discontinuous circumferential inner groove, and a locking ring (31) engaging in this inner circumferential groove to block the filling member (21) in position along the rotation axis (AX), the device being blocked between firstly the offset face (17) against which its radial portion (23) bears and secondly the ring (31) against which one edge of the centring ferrule (22) bears.
3. Disk according to claim 2, comprising at least one locking bolt (36) fixing the filling member (21) in rotation, this bolt (36) being positioned between two consecutive spurs (28) and joining them together, this bolt (36) comprising a groove (37) extending along the continuity of the grooves (29) in the two spurs (36) between which it is mounted to receive a corresponding portion of the locking ring (31), this bolt (36) comprising a blocking face against which the offset face of the hub (12) bears when this bolt (36) is in place, this blocking face comprising a radial groove wherein a portion of the radial segment (34) located between two spurs (28) joined together by this bolt engages, to block rotation of the filling member (21), the radial segment comprising an offset at the bolt (36) into which the bolt is engaged to block this bolt (36) in the radial direction.
4. Disk according to one of the above claims, wherein each blade (13) comprises a prolongation of its leading edge (18) or its trailing edge (19) towards the axis of rotation (AX) by which it is connected to the offset face of the hub (12), and wherein the outer ferrule (24) comprises a series of scallops or notches (27) wherein each prolongation (20) of the blade (13) fits when the filling member (21) is in place.
5. Disk according to claim 4, comprising a seal along an edge of the outer ferrule (24) to assure leak tightness between the outer ferrule (24) and the hub (12) with the blades (13) supported by this hub.
6. Disk according to one of the above claims, wherein the upstream face of the hub (12) is offset and fitted with the filling member (21).
7. Disk according to one of the above claims, wherein the downstream face of the hub (12) is offset and fitted with the filling member (21).
8. Turbomachine fan comprising a disk according to one of the above claims.
9. Turbojet type aircraft engine, comprising a blisk according to one of the above claims.

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