FR3095669A1 - Rotor disc with bolt-on insert - Google Patents

Abstract

The invention relates to a turbomachine rotor disc (12) extending around an axis (A), comprising an annular radial portion (14, 26) delimited axially by two side faces (14a) and provided with at least a fixing orifice (28, 30) which opens into the two lateral faces (14a) of said radial portion (14, 26), characterized in that the radial portion (14, 26) comprises a groove (36) formed in at least one of the two lateral faces (14a), and in the bottom of which said groove (36) the fixing orifice (28, 30) opens, and in that the disc (12) comprises an insert (38 ) disposed in the groove, said insert (38) having a through hole extending the fixing hole (28, 30). Figure for the abstract: figure 2

Description

Rotor disc with bolt insert

The invention relates to a turbomachine rotor disc which is intended to be assembled by bolting to another disc.

The invention relates more particularly to a turbomachine rotor disc designed to facilitate the manufacture of its fixing orifices.

Certain parts of an aircraft turbine engine, in particular the parts of the high pressure compressor or of the low pressure turbine of the turbine engine, comprise a plurality of rotor disks, each of which extends globally in radial planes with respect to the main axis of the turbomachine and which are fixed to each other.

According to one embodiment, the securing of a disk to another disk is carried out by bolting an annular flange coming from a disk of the rotor on the web of another disk of the rotor.

The canvas of this other disc therefore comprises a plurality of orifices allowing the passage of screws for bolting.

According to a known embodiment, the bolting screws are mounted adjusted in the orifices, in order to ensure the correct relative positioning of the two discs with respect to each other and with respect to the main axis of the turbomachine.

For this, it is important to control both the position of the holes intended for the passage of the screws and the diameter of these holes. Thus, the dimensional tolerances on the location and the diameter of these orifices are particularly low.

These dimensional tolerances are difficult to maintain for large diameter parts, in particular because of strong tendencies to deformation during machining. When the machining tolerances are not respected, the integration and assembly of the rotor is impacted or a disc can be directly scrapped if a machining is out of tolerance.

Thus, it is difficult to make orifices on the canvas of the disc whose positioning and dimensions are satisfactory for the positioning and fixing functions.

The object of the invention is therefore to propose a rotor disc which is produced to induce fewer constraints of dimensional tolerances at the level of the assembly orifices.

The invention proposes a turbomachine rotor disc extending around an axis A, comprising an annular portion delimited axially by two opposite end faces and provided with at least one fixing orifice which opens into the two faces of end of said annular portion,

characterized in that the annular portion comprises a groove formed in an end face a, and the fixing orifice opens into the bottom of the groove, and in that the disc comprises an insert placed in the groove, said insert having a through hole extending the fixing hole.

Preferably, each side face of the annular portion of the disc comprises at least one groove.

Preferably, the annular portion comprises a plurality of fixing orifices distributed circumferentially in a regular manner around said axis A, and the groove is annular and each fixing orifice opens at the bottom of the groove.

Preferably, said annular groove receives an annular insert which comprises a plurality of holes extending the fixing orifices.

Preferably, the insert is a ring split by a cutout.

Preferably, the annular portion comprises a plurality of fixing orifices distributed circumferentially in a regular manner around said axis A, and the end face of the annular portion comprises a plurality of grooves, each groove being associated with a Preferably , the dimensions of each groove, measured in the radial direction and in the circumferential direction, with respect to the axis are greater than the dimensions of the insert associated with it.

Preferably, the dimensions of each orifice for fixing the annular portion, measured in the radial direction and in the circumferential direction, are greater than the diameter of the hole in the insert.

Preferably, the groove comprises a radial wing which extends from an axial end of the groove, the wing axially delimiting the groove.

Preferably, the insert which is received in said groove comprises a notch complementary to the wing.

Other characteristics and advantages of the invention will appear on reading the detailed description which follows for the understanding of which reference will be made to the appended figures, among which:

is a schematic sectional representation along an axial plane of a bladed part of a turbomachine comprising at least one rotor disk produced according to the invention;

is a detail on a larger scale of the bladed part shown in Figure 1, showing the assembly of two adjacent discs with each other;

is a disassembled view of a disc represented in FIG. 2, showing in particular the inserts intended to be received in the grooves of the disc

is a schematic representation of an annular insert intended to be mounted in a groove of the disc represented in FIG. 3;

is an end view of a disc according to a second embodiment of the invention comprising a plurality of grooves;

is an enlarged detail of the disc shown in Figure 5, showing the grooves and mounting holes;

is a detail on an even larger scale of the disk represented in FIG. 5, showing the relative shapes and dimensions of the holes for fixing the disk in relation to the hole of an insert;

is a view similar to Figure 7, showing a possible positioning of an insert in the associated groove;

is a view similar to that of FIG. 8, showing an example of the dimensional relationship between a hole in the disc and the hole in the insert;

is a view similar to that of FIG. 8, showing another possible positioning of the insert in the associated groove.

There is shown in Figure 1 a part of a turbomachine rotor which carries moving blades. This part, also called the bladed part, is for example the moving part of a turbine engine low-pressure turbine 10 and it comprises several rotor discs 12 each of which corresponds to a stage of the turbine 10. It will be understood that the invention does not is not limited to the discs 12 of the rotor of the low pressure turbine 10 and that the description of the invention which will follow can relate to any other bladed part of the rotor of the turbomachine, which belongs for example to the high pressure turbine, the compressor low pressure or high pressure compressor.

Each rotor disc 12 is coaxial with the main axis A of the turbomachine and it comprises an annular radial web 14, a hub 16, or bore, radially central and located at the radially inner end of the web 14 and a rim 18 located at the radially outer end of the fabric 14.

The rim 18 is shaped to support the blades 20 of the stage of the turbine 10, it comprises for this purpose a plurality of cells hollowed out at its peripheral, which receive the roots of the blades 20.

All the discs 12 of the low pressure turbine 10 are integral with each other in rotation around the main axis A of the turbomachine.

For this, some discs 12 include a ferrule 24 which extends axially in the direction of an axially adjacent disc 12. The free axial end of the ferrule 24 includes an annular flange 26 which is fixed to the web 14 of the adjacent disc.

The fastening of each flange 26 with the fabric 14 which is associated with it is carried out by bolting, that is to say a plurality of screws 32 and nuts 34 which tighten the flange or flanges 26 on the fabric 14. The fabric 14 comprises for this purpose a plurality of orifices 28 passing through the fabric 14 and which are arranged to be aligned with associated orifices 30 formed in the flanges 26.

According to the embodiment shown in Figure 1, with reference to an order of the discs 12 going from upstream to downstream, which will be the axial orientation going from left to right, the first disc 12, c ie the one which is located furthest to the left, comprises a ferrule 24 extending axially downstream as far as the second disc 12; the second disc 12 comprises a ferrule 24 extending axially downstream as far as the third disc 12 and the fourth disc 12 comprises a ferrule 24 extending axially upstream as far as the third disc 12.

The third disc 12 does not include a ferrule 24 and receives two flanges 26 located axially on either side of this third disc 12.

It will be understood that the invention is not limited to this distribution of ferrules 24 and that any variant may be concerned by the present invention.

For example, two discs 12 can be joined together by two flanges 26 each carried by one of the two discs.

In the case here of the third disc 12, on which the flange 26 coming from the second disc 12 and the flange 26 coming from the fourth disc 12 are fixed, each orifice 28 of the fabric 14 is aligned with an orifice 30 of the flange 26 coming from the second disc 12 and with an orifice 30 of the flange 26 coming from the fourth disc 12.

Each flange 26 of the first, second or fourth disc 12 is in contact with an axial end face 14a of the web 14 of the second or third disc 12.

Each face 14a of the fabric 14 extends in a radial plane with respect to the main axis of the disc 12, that is to say a plane perpendicular to the main axis A of the disc 12.

Each flange 26 has a radial face which comes into contact and is clamped against face 14a of fabric 14 by the bolts formed by screws 32 and nuts 34.

In the following description, reference will be made to a disc 12. It will be understood that the invention is not limited to this embodiment and that it can be applied by analogy to the flange 26 of one of the first, second or fourth disc 12.

As can be seen in more detail in Figures 2 and 3, a first disc 12, here the disc shown on the right of Figure 2 carries a ferrule 24 ending in a flange 26, which is in contact with a face 14a of the web 14 of the second disc 12.

The canvas 14 of the second disc 12, to which the flange 26 is fixed, comprises a plurality of orifices 28 distributed circumferentially around the axis A and at the same radial distance from the latter.

The fabric 14 of the second disc 12 also comprises, on each of its side faces 14a, a groove 36 into which each orifice 28 opens.

An insert 38 is arranged inside this groove 36 and it comprises at least one hole 40 which is also intended to be traversed by the rod of a screw 32. Thus, when the insert 38 is in place in the groove 36, its hole 40 extends the orifice 28 of the fabric 14.

The disc 12 also comprises means carrying out the axial retention of the insert 38 in the groove 36.

These retaining means are particularly useful before the assembly of the two discs 12 with each other, to avoid the separation of the insert 38 from the disc 12.

For this, as can be seen in more detail in Figure 3, each groove 36 has a flange 44 extending mainly radially.

This wing 44 is mounted flush with the side face 14a of the canvas 14, so as not to harm the bearing of the flange 26 against this side face 14a.

Here, the wing 44 is carried by an edge of the groove 36, which radially delimits the groove 36, here the radially inner end edge of the groove 36, and the wing 44 extends radially outwards towards the other edge of the groove 36. It will be understood that the invention is not limited to this embodiment and that the wing 44 can also extend radially in the direction of the main axis A, from a radially outer edge of the groove 36.

As can be seen in particular in Figure 3, the insert 38 includes a notch 46 complementary to the wing 44, so that the section of the insert 38 corresponds to the section of the groove 36, taking into account the presence of the wing 44.

According to a first embodiment that can be seen in Figures 4 and 5, the groove 36 which is formed in each side face 14a of the fabric 14 is of annular shape centered on the main axis of the second disc 12. All orifices 28 of this fabric 14 open into this single groove 36.

Thus, each side face 14a of the fabric 14 has a single groove 36.

Also, a single insert 38 is arranged in this groove 36. The single insert 38 also has an annular shape.

The number of holes 40 of the insert is equal to the number of orifices 28 of the disc 12 and they are distributed to extend the orifices 28 of the disc 12, when the insert 38 is correctly positioned in the groove.

Insert 38 has a cutout 42 so that insert 38 consists of a split ring. The purpose of the cutout 42 is in particular to allow the mounting of the insert in the groove 36. Indeed, thanks to the presence of the cutout 42, it is possible to deform the insert 38 to increase its diameter and allow its mounting in throat 36.

There is shown in Figures 6 and following another embodiment in which each side face 14a of the fabric 14 comprises a plurality of grooves 36, each groove 36 of which is associated with an orifice 28 of the fabric 14. Each side face 14a of the canvas 14 thus has as many grooves 36 as canvas 14 has orifices 28.

The assembly further comprises a plurality of inserts 38 which are distributed in all the grooves 36 and an insert 38 comprising a hole 40 is arranged in each groove 36.

According to this embodiment, the position of each insert 38 in the groove 36 associated with it can be modified in the radial direction and the circumferential direction.

For this, according to a first aspect, and as can be seen in Figures 7 and 8, the circumferential dimension of each groove 36 is greater than the circumferential dimension of the insert 38, making it possible to adjust the circumferential position of the insert in the throat 36.

Similarly, as can be seen in Figure 8, the radial dimension of the groove 36, that is to say its dimension in a direction perpendicular to the main axis A of the disc, is greater than the radial dimension of insert 38.

This allows for example the insert 38 to press it radially against a radially inner edge of the groove 36 and a radial play is present between the insert 38 and the radially outer edge of the groove 36.

Also, to allow this adjustment of the position of the insert 38 in the groove 36, the dimensions of the orifice 28 of the fabric 14, which is associated with the groove 36 and the insert 38, are greater than the diameter of the hole 40 of insert 38.

For this, the section of the orifice 28 may not be circular.

By way of non-limiting example, as can be seen in Figure 9, the length of the orifice 28 of the fabric 14, measured circumferentially, is substantially equal to twice the diameter of the hole 40 of the insert 38, as it has been represented schematically by the dotted circles.

According to a variant embodiment represented in particular in FIGS. 7 and 10, the orifice 28 of the fabric 14 is of oblong or oval shape, its largest dimension here being oriented in the circumferential direction and its smallest dimension being radial, each of the two dimensions of the orifice being greater than the diameter of the hole 40 of the insert 38.

The insert 38 is a component of reduced dimensions compared to the dimensions of the second disc 12. Thus, it is easier to produce this component with reduced dimensional tolerances and in return, to produce the orifice 28 of the fabric with dimensions or larger dimensional tolerances.

In addition, it is possible to adjust the positioning of the insert 38 in the groove 36 so that the hole 40 of the insert 38 is positioned with its axis coaxial with the axis of an orifice 30 of the flange 26.

Each orifice 28 of the fabric 14 then only has the function of allowing the passage of the screw 32 of the bolt.

Also, in the case of a problem making the hole 40 of an insert, only the insert 38 will be scrapped, unlike the solutions of the prior art for which the entire disk 12 could be scrapped. if re-machining was not possible.

The costs induced by such disposal of the insert 38 alone are therefore reduced.

As previously stated, the invention does not only relate to the web 14 of a disc having one or more grooves 36 in its side faces, but it may also relate to the radial annular flange 26 which is intended to come into contact against one of the side faces 14a of the fabric 14 of a disc or against a radial annular flange 26 of another disc 12.

In such a case (not shown), the two side faces of the flange 26 then comprise one or more grooves each receiving an insert.

The description of the grooves 36 and the inserts 38 which has just been made for their application on the fabric 14 of a disc will apply in a similar way to the grooves and inserts of the flange 26.

Claims (10)

Turbomachine rotor disc (12) extending around an axis (A), comprising an annular portion (14, 26) delimited axially by two opposite end faces (14a) and provided with at least one attachment (28, 30) which opens into the two end faces (14a) of said annular portion (14, 26),
characterized in that the annular portion (14, 26) comprises a groove (36) formed in an end face (14a), and the fixing orifice (28, 30) opens into the bottom of the groove (36) ,
and in that the disc (12) comprises an insert (38) disposed in the groove, said insert (38) having a through hole (40) extending the fixing orifice (28, 30). Rotor disc (12) according to Claim 1, characterized in that each lateral face (14a) of the annular portion (14, 26) of the disc (12) comprises at least one groove (36). Rotor disk (12) according to Claim 1 or 2, in which the annular portion (14, 26) comprises a plurality of fixing orifices (28, 30) distributed circumferentially in a regular manner around the said axis (A), characterized in that the groove (36) is annular and each fixing orifice (28, 30) opens out at the bottom of the groove (36). Rotor disk (12) according to Claim 3, characterized in that the said annular groove (36) receives an annular insert (38) which comprises a plurality of holes (40) extending the fixing orifices (28, 30). Rotor disk (12) according to the preceding claim, characterized in that the insert (38) is a ring split by a cutout (42). Rotor disk (12) according to Claim 1 or 2, in which the annular portion (14, 26) comprises a plurality of fixing orifices (28, 30) distributed circumferentially in a regular manner around the said axis (A), characterized in that the end face (14a) of the annular portion (14, 26) comprises a plurality of grooves (36), each groove (36) being associated with a fixing orifice (28, 30) and receiving a insert (38) associated with it. Rotor disk (12) according to any one of the preceding claims, characterized in that the dimensions of each groove (36), measured in the radial direction and in the circumferential direction, with respect to the axis (A) are greater to the dimensions of the insert (38) associated with it. Rotor disc (12) according to Claim 7, characterized in that the dimensions of each fixing orifice (28, 30) of the annular portion (14, 26) measured in the radial direction and in the circumferential direction, are greater than the diameter of the hole (40) of the insert (38). Rotor disc (12) according to any one of the preceding claims, characterized in that the groove (36) comprises a radial flange (44) which extends from an axial end of the groove (36), the wing axially delimiting the groove (36). Rotor disc (12) according to the preceding claim, characterized in that the insert (38) which is received in the said groove (36) comprises a notch (46) complementary to the wing (44).