FR3025559B1 - ASSEMBLY OF ELEMENTS FOR A TURBOMACHINE - Google Patents

Abstract

A set of elements for a turbomachine, comprising first and second annular rotor members (10, 12), the first rotor element comprising a toothing (16) configured to be axially engaged in a toothing (18) substantially complementary to the second element rotor arrangement so as to form a connection (20) between the rotor elements, and sealing means configured to provide airtightness at said connection, characterized in that said sealing means comprise at least a brush seal (24, 26) which is mounted between one of said rotor members and a third annular member (28) extending at said link.

Description

Set of elements for a turbomachine

TECHNICAL AREA

The present invention relates to a set of elements for a turbomachine and in particular rotor elements which are connected together by a gear coupling, for example that commonly called curvic coupling.

STATE OF THE ART

It is known to couple two annular rotor elements by a gear connection (generally substantially trapezoidal). A first one of the rotor elements comprises a toothing configured to be axially engaged in a toothing substantially complementary to a second one of the rotor elements so as to form a connection between the rotor elements. The rotor elements are here of substantially the same diameter as opposed to a splined connection between two shafts for example, which are engaged in one another and therefore have different diameters.

This type of coupling has many advantages. It allows on the one hand to ensure "self-centering" of the rotor elements and to obtain precise axial and radial positioning of these elements. It also makes it possible to assemble the rotor elements with a small space, in particular with respect to a bolted connection. It also makes it possible to allow relative displacements between the rotor elements, in both radial and axial directions.

The shapes of the teeth are not perfectly complementary. Games therefore exist between the teeth and in particular between the tops of the teeth of one of the teeth and the teeth of the other teeth. The major disadvantage of this technology is that it does not guarantee a radial air seal between the space located radially inside the coupling and the space located radially outside thereof.

It is therefore necessary and common to associate sealing means with this type of coupling to ensure airtightness at the coupling.

In the present art, the sealing means are mounted radially inside the coupling zone so that, in use, because of the centrifugal forces, these means are biased radially outwards and are plated. against the parts of the rotor elements having the teeth, thereby providing airtightness therethrough. These sealing means are in the form of an annular sheet flat section or V-section, and are housed in a groove under the teeth of the coupling.

However, this solution is not always optimized in terms of leakage flow.

In addition, during assembly, there is a risk of poor positioning of these sealing means in the groove, and therefore a risk of occurrence of a leakage flow. Furthermore, in operation, due to thermal expansion and centrifugal forces, the ferrules which carry the teeth can deform radially, and result in a risk of poor plating of the sealing means and therefore leakage flow. Finally, some of these sealing means are not continuous over 360 °, which generates the creation of an additional set and therefore a leakage rate.

The present invention provides in particular a simple, effective and economical solution to at least some of these problems.

SUMMARY OF THE INVENTION The invention proposes a set of elements for a turbomachine, comprising first and second annular rotor elements of substantially the same diameter, the first rotor element comprising a toothing configured to be engaged axially in substantially complementary toothing. the second rotor element so as to form a connection between the rotor elements, and sealing means configured to provide airtightness at said connection, characterized in that said sealing means comprise at least a brush seal which is mounted between one of said rotor members and a third annular member extending at said link.

The sealing means according to the invention make it possible to solve the problems mentioned above by providing contact sealing while permitting axial and radial relative displacements of the rotor elements. This allows sealing without impacting the mounting and operation of the teeth. The sealing means according to the invention are perfectly compatible with the gear coupling because they are compact and can easily integrate into the environment. The assembly according to the invention may comprise one or more of the following characteristics, taken separately or in combination with each other: the sealing means comprise two brush seals which are mounted respectively upstream and downstream said link; said third element is a stator element, and is for example a compressor rectifier or a turbine distributor (as regards the rectifier, it may be a variable-pitch rectifier ring or a ring fixed rectifier (the ring can in this case be sectored)); the or each seal then provides a dynamic seal since it is mounted between a rotor element and a stator element; said third stator element carries an upstream brush seal, whose brush cooperates with said first rotor element, and a downstream brush seal, whose brush cooperates with said second rotor element; said third element is a rotor element which is carried by one of said first and second rotor elements; the seal then provides a quasi-static seal since it is mounted between two stator elements, this type of seal having the advantage of having a good service life; said third rotor element comprises a ring extending radially inside or outside said connection; said ring extends radially outside said connection and cooperates with a brush with a brush seal which is carried by the rotor element which is not carried by the ring; said ring comprises radially outer wipers configured to cooperate with a ring made of abradable material; said ring extends radially inside said connection and carries at least one brush seal; the brush cooperates with the rotor element which does not carry the ring.

The present invention also relates to a turbomachine comprising at least one assembly as described above.

DESCRIPTION OF THE FIGURES The invention will be better understood and other details, characteristics and advantages of the invention will become apparent on reading the following description given by way of nonlimiting example and with reference to the appended drawings in which: FIG. 1 is a partial schematic view in axial section of an assembly comprising two rotor elements for a turbomachine, these rotor elements being connected together by a gear coupling; - Figure 2 is a partial schematic perspective view of the gear coupling of Figure 1; - Figure 3 is a schematic sectional view of a set of rotor elements for a turbomachine, equipped with sealing means according to the prior art; - Figure 4 is a schematic sectional view of a first embodiment of a set of rotor elements for a turbomachine, according to the invention; - Figure 5 is a schematic sectional view of a second embodiment of a set of rotor elements for a turbomachine, according to the invention; - Figure 6 is a schematic sectional view of a third embodiment of a set of rotor elements for a turbomachine, according to the invention; and FIG. 7 is a diagrammatic sectional view of a fourth embodiment of an assembly of rotor elements for a turbomachine, according to the invention.

DETAILED DESCRIPTION

Reference is first made to FIGS. 1 and 2 which represent an assembly of two rotor elements 10, 12 for a turbomachine, these rotor elements being for example DAMs, an acronym for a blisk.

The first rotor element 10, on the left in the drawing or upstream with reference to the direction of flow of the gases in the turbomachine, comprises a cylindrical portion 14 whose free downstream end comprises a toothing 16, that is to say say an annular row of teeth that are here oriented axially downstream.

The second rotor element 12, on the right in the drawing or downstream, comprises a cylindrical portion 17 whose free upstream end comprises a toothing 18 which has a shape substantially complementary to that 16 of the first rotor element 10 and which comprises teeth oriented axially upstream. The portions 14, 17 have substantially the same diameter.

The toothing 16 is intended to be engaged axially in the toothing 18, as can be seen in FIG. 2, so as to form a connection 20 between the elements 10, 12, which is commonly called curvic coupling or trapezoidal tooth coupling in the field. aeronautics.

As seen in Figure 2, the tops of the teeth of the toothing 16, 18 are not supported on the teeth of the toothing 18, 16, which generates radially air passage clearances. Air can thus flow through the connection 20, mainly from the inside of the portions 14, 18 radially outwardly thereof.

The link 20 is intended to transmit a torque while allowing small relative displacements between the rotor elements 10, 12.

As explained in the foregoing, it is known to associate with this connection 20 airtight sealing means, such as those shown in FIG.

The sealing means of FIG. 3 are formed by an annular plate 22 with a flat section which is mounted radially inside the connection and which is designed to bear radially on the free ends of the rotor elements 10, 12 carrying the teeth 16, 18 to limit or prevent the passage of air through the connection 20.

However, this technology has disadvantages described above. The invention makes it possible to provide a solution to these drawbacks by means of at least one brush seal which is mounted between one of the rotor elements and a third annular element extending at the level of the connection.

Figures 4 to 6 show several embodiments of the invention in which the parts already described in the foregoing are designated by the same references.

Referring firstly to the embodiment of Figure 4 wherein the sealing means comprise two brush seals respectively upstream 24 and downstream 26. The seals 24, 26 are here mounted between a (third) here element of stator 28, which is a compressor rectifier or a turbine distributor.

Each seal 24, 26 comprises an annular brush support 30 and an annular brush 32, the support 30 being here fixed to the inner periphery of the stator element 28 and the brush 32 cooperating by friction with one of the rotor elements 10, 12. The upstream gasket 24 is located at an upstream end of the stator element 28 and its brush 32 cooperates with the first rotor element 10, and the downstream gasket 26 is located at a downstream end of the rotor element. stator element 28 and its brush 32 cooperates with the second rotor element 12.

Air from the annular cavity located radially inside the portions 14, 17 can pass radially outwardly through the link 20 (arrow 34) and vice versa from the outside to the inside. This embodiment makes it possible to limit the rate of passage of this air towards the annular cavities located upstream and downstream of the stator element 28 (arrows 36). It also makes it possible to limit the air or gas flow rate of the cavity located downstream of the stator element 28, upstream (arrow 38 - because the pressure of the gases downstream of the element 28 is greater than that upstream of the element).

In a variant not shown, more than two brush joints could be mounted between the stator element 28 and the portions 14, 17, and for example two joints upstream of the link 20 and two joints downstream of the link 20.

Referring now to the embodiment of Figure 5 wherein the sealing means comprise a single brush seal 40. The seal 40 is here mounted between a (third) element here rotor 42, which is a ring which extends here radially outside the connection 20 and at radial distance therefrom. The upstream end of the element 42 is fixed, for example by shrinking, to the first rotor element 10. The rotor element 42 is equipped with annular wipers 44 extending radially outwards and cooperating by friction with a annular ring 46 of abradable material carried by a stator element 28 of the type described in the foregoing.

The seal 40 comprises an annular brush holder 30 and an annular brush 32, the support 30 being fixed here to the portion 17 of the second rotor element 12 and the brush 32 cooperating by friction with a downstream end of the element The seal 40 is here located downstream of the connection 20, at the downstream end of an annular space delimited by the rotor element 42.

Air from the annular cavity located radially inside the portions 14, 17 can pass radially outwardly through the link 20 (arrow 34) and vice versa. This variant embodiment makes it possible to limit the rate of passage of this air towards the annular cavity situated downstream of the stator element 28 (arrow 36). Furthermore, the labyrinth seal defined by the wipers 44 and the abradable ring 46 limits the flow rate of air or gas from the downstream cavity to the cavity located upstream of the stator element 28 (arrows 38 ).

Referring now to the embodiment of Figure 6 wherein the sealing means comprise a single brush seal 50. The seal 50 is here mounted between a (third) element here rotor 48, which is a ring which here extends radially inside the connection 20 and at a radial distance therefrom. The upstream end of the element 48 is fixed, for example by shrinking, to the first rotor element 10.

The seal 50 comprises an annular brush holder 30 and an annular brush 32, the support 30 being here fixed to the downstream end of the rotor element 48 and the brush 32 cooperating by friction with the portion 17 of the second rotor element 12. The seal 50 is here located downstream of the link 20, at the downstream end of an annular space delimited by the rotor element 48.

This variant embodiment makes it possible to limit the rate of passage of the air between the annular cavity located radially inside the portions 14, 17 and the aforementioned annular space and up to the connection 20 (arrow 52). Moreover, a labyrinth seal defined by wipers 44 of the first rotor element 10 and an abradable ring 46 of a stator element 28 of the aforementioned type makes it possible to limit the flow rate of air or gas passage from the downstream upstream of this stator element (arrows 38).

Referring now to the embodiment of Figure 7 wherein the sealing means comprises two brush seals 60. The seals 60 are here mounted between a (third) element here rotor 54, which is a ring which extends here radially inside the connection 20 and at radial distance therefrom. A first seal 60 is mounted between the upstream end of the element 54 and the first rotor element 10 and a second seal 60 is mounted between the downstream end of the element 54 and the second rotor element 12. The ends of the element 54 are radially supported and thus centered on annular bearings of the rotor elements 10, 12, respectively.

Each seal 60 comprises an annular brush holder 30 and an annular brush 32, the support 30 being here fixed to one end of the rotor element 54 and the brush 32 cooperating by friction with the portion 14 of the first element of rotor 10 or with the portion 17 of the second rotor element 12. The seals 60 are here respectively upstream and downstream of the link 20, at the upstream and downstream ends of an annular space delimited by the rotor element 54.

This variant embodiment makes it possible to limit the rate of passage of the air located in the annular cavity situated radially inside the portions 14, 17 in the aforementioned annular space and up to the connection 20 (arrow 52). Moreover, a labyrinth seal defined by wipers 44 of the first rotor element 10 and an abradable ring 46 of a stator element 28 of the aforementioned type makes it possible to limit the flow rate of air or gas passage from the downstream upstream of this stator element (arrows 38).

The brush seals 24, 26, 40, 50 and 60 may be metal brush or carbon brush seals.

Of course, in the examples described above and shown in the drawings, the mounting of each brush seal could be reversed. In the case for example of FIG. 4, the supports 30 of the joints could be fixed to the rotor elements 10, 12, respectively, and their brushes 32 could cooperate by friction with the stator element 28.

Claims (10)

An assembly of elements for a turbomachine, comprising first and second annular rotor members (10, 12) of substantially the same diameter, the first rotor element comprising a toothing (16) configured to be axially engaged in a toothing (18). ) substantially complementary to the second rotor element so as to form a connection (20) between the rotor elements, and sealing means configured to provide airtightness at said connection, characterized in that said means sealing members comprise at least one brush seal (24, 26, 40, 50, 60) which is mounted between one of said rotor members and a third annular member (28, 42, 48, 54) extending at said link. An assembly according to claim 1, wherein the sealing means comprises two brush seals (24, 26) which are mounted respectively upstream and downstream of said link (20). An assembly according to claim 1 or 2, wherein said third member is a stator member (28), and is for example a compressor straightener or a turbine distributor. 4. The assembly of claim 3, in dependence on claim 2, wherein said third stator element (28) carries an upstream brush seal (24), whose brush (32) cooperates with said first element of rotor (10), and a downstream brush seal (26), the brush (32) of which cooperates with said second rotor member (12). An assembly according to claim 1 or 2, wherein said third member is a rotor member (42,48,54) which is carried by one (10) of said first and second rotor members. The assembly of claim 5, wherein said third rotor member (42, 48, 54) comprises a ring extending radially inside or outside said link (20). An assembly according to claim 6 wherein said ring extends radially outwardly of said linkage (20) and cooperates with a brush (32) of a brush seal (40) which is carried by the rotor element (12) which does not bear the ring. 8. The assembly of claim 7, wherein said ring (42) comprises radially outer wipers (44) configured to cooperate with a ring (46) of abradable material. 9. The assembly of claim 6, wherein said ring extends radially inside said connection (20) and carries at least one brush seal (50, 60). 10. Turbomachine, characterized in that it comprises at least one assembly according to one of the preceding claims.