ELECTRIC MODULE FOR AN AIRCRAFT TURBOMACHINE

Abstract

An electric module for an aircraft turbomachine includes an electric machine stator having an annular shape around an axis (A) and being configured to surround a rotor of the electric machine, and an annular support element of the stator. The support element includes an outer annular surface configured to be swept over by a gas stream (F) from the turbomachine with a view to conductively cooling the stator.

Claims

1. An electric module (M) for an aircraft turbomachine, the module comprising: a stator of an electric machine, said stator having an annular shape about an axis (A) and being configured to surround a rotor of the electric machine, an annular support element for said stator, said support element comprising an external annular surface configured to be swept by a gas flow (F) from the turbomachine, the gas flow (F) cooling the stator by conduction, said support element comprising: an annular support which surrounds and covers at least one portion of said stator and which is attached to the external periphery of the stator, the support comprising at least one flange configured to attach to a member of the turbomachine and being located at the downstream end of the stator, and an annular cover which surrounds and covers at least one portion of said support and which comprises said external annular surface swept by the gas flow (F).

2. The module (M) according to claim 1, wherein the support comprises a cylindrical wall covering the stator and connected by its downstream end to said flange which is U-shaped in cross-section to define an annular space (X) for electrical connection of said stator.

3. The module (M) of claim 1, wherein the cover comprises at an upstream end an internal cylindrical surface configured to cooperate with annular wipers of a labyrinth seal.

4. The module (M) according to claim 1, wherein said external annular surface swept by the gas flow (F) extends over the entire longitudinal extent of said cover.

5. The module (M) according to claim 1, wherein the cover comprises orifices oriented radially with respect to the axis (A), these orifices being aligned with threaded holes formed in the support, screws being configured to be screwed into the orifices and the holes in order to secure the cover to the support.

6. The module (M) according to claim 1, wherein the cover comprises at its downstream end an annular groove oriented axially downstream and configured to receive a peripheral edge of another member of the turbomachine.

7. An aircraft turbomachine, comprising: a gas generator having a longitudinal axis (A), a fan located at an upstream end of the gas generator and configured to rotate about said axis, and an electric machine with an annular shape which is mounted coaxially downstream of the fan, and which comprises a rotor rotatably coupled to the fan, and a module (M) according to claim 1, the fan being configured to generate a main gas flow (F), a portion of which flows in a primary annular duct of the gas generator to form a primary flow, and another portion of which flows in a secondary annular duct extending between the gas generator and a nacelle casing to form a secondary flow, the primary duct being delimited by a first and a second annular envelopes coaxial with the gas generator, the primary duct being traversed by arms, referred to as IGV, configured to connect the first and second envelopes, as well as by tubular arms of an inlet casing located downstream of the IGV, the gas generator comprising a third annular envelope which coaxially surrounds the second envelope, the second and third envelopes being connected together at their upstream ends to form an annular splitter nose that separating that separates the primary and secondary flows.

8. The turbomachine of claim 7, wherein the IGV are integrally formed with annular segments of the first, second, and third envelopes, this assembly being configured to be attached to said inlet casing.

9. The turbomachine according to claim 7, wherein said assembly comprises at its external periphery an annular flange configured to attach to the inlet casing, and at its internal periphery, annular edges, respectively upstream and downstream, for support and/or engagement.

10. The turbomachine according to claim 7, wherein the electric machine and the inlet casing are attached to an annular bearing support of the gas generator, said flange being applied to and attached to the bearing support and/or to the casing.

11. The turbomachine according to claim 7, further comprising a nacelle casing that surrounds the gas generator, as well as bladings, referred to as OGV configured to connect the nacelle casing to said third annular envelope.

12. A method for maintaining a turbomachine according to claim 8, comprising the steps of: disassembling and removing the rotor from the electric machine, disassembling and removing said cover from the rest of the electric module, disassembling and removing said assembly, disassembling and removing the rest of the electric module.

Description

BRIEF DESCRIPTION OF FIGURES

[0053] The invention will be better understood and further details, characteristics and advantages of the invention will become apparent from the following description made by way of non-limiting example with reference to the attached drawings, in which:

[0054] FIG. 1 is a schematic view in axial section of an aircraft turbomachine with a high bypass ratio and reducer;

[0055] FIG. 2 is a partial schematic half-view in axial section of an aircraft turbomachine according to the invention equipped with an electric machine;

[0056] FIG. 3 is a larger scale view of a portion of FIG. 2 and shows an electric module according to the invention;

[0057] FIGS. 4a to 4d are views similar to FIG. 3 and illustrate steps of a method in the maintenance of the turbomachine,

[0058] FIG. 5 is a schematic perspective view of a portion of the turbomachine in FIG. 2 and illustrates one of the steps in the maintenance method of the turbomachine,

[0059] FIG. 6 is a schematic cross-sectional view of an electric harness, and

[0060] FIG. 7 is a schematic cross-sectional view of an embodiment of an electric connection bar.

DETAILED DESCRIPTION OF THE INVENTION

[0061] First, reference is made to FIG. 1, which schematically depicts a double-body and double-flow aircraft turbomachine 10.

[0062] The turbomachine 10 conventionally comprises a gas generator 12, upstream of which is arranged a fan 14. The fan 14 is surrounded by a casing 16 which is surrounded by a nacelle 18 that extends around and along a major portion of the gas generator 12.

[0063] The gas generator 12 here comprises two bodies, namely a low-pressure body 12a or LP and a high-pressure body 12b or HP. Each body comprises a compressor and a turbine.

[0064] The terms “upstream” and “downstream” are considered along a main direction F of flow of the gases in the turbomachine 10, this direction F being parallel to the longitudinal axis A of the turbomachine.

[0065] From upstream to downstream, the gas generator 12 comprises a low-pressure compressor 20, a high-pressure compressor 22, a combustion chamber 24, a high-pressure turbine 26 and a low-pressure turbine 28.

[0066] The fan 14 comprises an annular row of vanes 30 driven in rotation by a fan shaft 32 which is connected to the rotor of the low-pressure body 12a by means of a reducer 33. The gas flow passing through the fan (arrow F) is separated upstream of the gas generator 12 by an annular splitter nose 34 into a radially internal annular flow, referred to as primary flow 36 that flows in a primary annular duct of the gas generator 12, and a radially external annular flow, referred to as secondary flow 38 that flows in a secondary annular duct between the gas generator 12 and the nacelle 18 and provides most of the thrust for the turbomachine.

[0067] An inlet casing 40 structurally connects the gas generator 12 to the casing 16 and to the nacelle 18. The inlet casing 40 comprises an annular row of radially internal arms 42 extending into the flow duct of the primary flow 36, and an annular row of radially external straightener bladings 44, referred to as OGV (acronym for Outer Gear Vane), extending into the flow duct of the secondary flow 38.

[0068] The arms 42 are generally limited in number (less than ten) and are tubular and crossed by auxiliaries.

[0069] These arms 42 have a structural role because they allow the transmission of forces between the bearing supports and the suspensions. They also have a role of passage of the auxiliaries, allowing to make cross the auxiliaries through the duct by fairing them, thus limiting the aerodynamic losses in the duct. These arms do not have a flow straightening function because they have no camber and are not sufficient in number to carry out this function.

[0070] The number of straightener bladings (OGV) is generally higher than ten. They allow to straighten the flow of the fan thanks to a specific number and camber. They also have a structural function because they support the casing around the fan (fan casing).

[0071] The flow duct of the primary flow 36 is also traversed by straightener bladings 52, referred to as IGV (acronym for Inner Gear Vane). The IGV 52 are evenly distributed around the axis A and are located upstream of the inlet casing 40 and more precisely upstream of the arms 42. These bladings allow to straighten the flow coming from the fan when it enters the primary duct. They do not have a structural role. They are in sufficient number (for example more than 10) and with a certain camber to straighten the flow of the fan penetrating the primary duct.

[0072] The flow duct of the primary flow 36 is delimited by two coaxial annular envelopes, respectively internal 37a and external 37b. In particular, the IGV 52 and the arms 42 are connected to these envelopes 37a, 37b. The flow duct of the secondary flow 38 is delimited internally by an annular envelope 39 coaxial with the envelopes 37a, 37b, and externally by the nacelle casing 16. The OGV 44 are connected to the envelopes 37b, 39.

[0073] Each of the envelopes 37a, 37b, 39 may be formed by several adjacent walls or covers.

[0074] The rotor of the low-pressure body 12a as well as the fan shaft 32 are guided upstream by bearings 46, 48 and 50. These bearings 46, 48, 50 are of the ball or roller type and each comprise an internal ring mounted on the shaft to be guided, an external ring carried by an annular bearing support and a bearing between the rings.

[0075] In a known manner, the reducer 33 is of the epicyclic gear train type and comprises a sun gear centred on the axis A, a ring gear extending around the axis, and planet gears that mesh with the sun gear and the ring gear and are carried by a planet carrier.

[0076] In the example shown, the ring gear is stationary and fixedly connected to a support 62 of the bearings 46, 48. The planet carrier is rotatable and coupled by the fan shaft 32. The sun gear of the reducer is coupled by an input shaft 56 to the main shaft 58 of the low-pressure body.

[0077] The input shaft 56 is guided by the bearing 50 which is carried by a bearing support 60. The fan shaft 32 is guided by the bearings 46, 48.

[0078] The bearing supports 60, 62 extend around the axis A and are stationary parts connected to the stator and in particular to the input casing 40.

[0079] FIG. 2 is a larger scale, more detailed view of a portion of FIG. 1, and illustrates one embodiment of a turbomachine according to the invention.

[0080] The elements of FIG. 2 that have already been described with reference to FIG. 1 are designated by the same references.

[0081] In particular, FIG. 2 shows the area Z between the fan disc 32a and the reducer 33, in which an electric machine 70 is installed. Only one support 33a of the ring gear of the reducer 33 is visible in FIG. 2, this element being connected, for example, to the input casing 40 or to the bearing support 62.

[0082] The cross-section in the drawing in FIG. 2 passes through one of the IGV 52, which may be full. At least one or some of the IGV 52 may be tubular. The cut passes through an OGV 44 as well as through an arm 42 which is tubular for the passage of auxiliaries, as mentioned above. The tubular IGV 52 and/or the tubular arm 42 may have electrical connection means passing through it, which will be described in the following.

[0083] Each arm 42 comprises upstream an edge 42a and downstream an edge 42d, respectively leading edge and trailing edge of the primary flow 36.

[0084] Each arm 42 comprises an internal cavity 42c that is closed radially outward by a wall 44a of the OGV 44. This wall 44a is integrally formed with the OGV 44 and is attached to annular flanges, respectively upstream 43a and downstream 43b, of the inlet casing 40. The cavity 42c is isolated from the auxiliaries by the wall 42b.

[0085] The internal cavity 42c of each arm 42 is closed radially inward by an annular wall 40a of the inlet casing 40. At the upstream end of this wall 40a, the inlet casing 40 comprises a radially internal annular flange 40b for attachment of the bearing support 62. At the downstream end of the wall 40a, the inlet casing 40 comprises a radially internal annular flange 40c for attaching, for example, an annular gutter for collecting oil sprayed by the reducer 33 by centrifuging.

[0086] The reducer 33 as well as the bearings 46, 48, 50 visible in FIG. 1 are located in an annular lubrication enclosure E which is sealed upstream by the bearing support 62 and at least one non-visible seal, and downstream by the bearing support 60 and at least one non-visible seal. The external periphery of the enclosure E is sealed in particular by the wall 40a.

[0087] FIG. 2 allows to show that the envelope 37a mentioned above is formed of several successive walls such as the wall 40a and an annular shroud 64 located upstream of the wall 40a and connected to the internal periphery of the IGV 52.

[0088] The envelope 37b is formed by several successive walls and in particular an annular shroud 66 located upstream of the inlet casing 40. This shroud 66 extends around the shroud 64 and is connected to the external periphery of the IGV 52.

[0089] The envelope 39 is formed of several successive walls such as the wall 44a and an annular shroud 68 located upstream of the wall 44a. This shroud 68 extends around the shroud 66 and the upstream ends of the shrouds 66, 68 are connected together to form the splitter nose 34.

[0090] As discussed above, the electric machine 70 is located in an annular area Z, this area Z being delimited here upstream by the fan 14, and in particular the disc 32 connecting the fan vanes 30 to the fan shaft 32, and downstream by the bearing support 62.

[0091] The machine 70, best seen in FIG. 3, has a generally annular shape and comprises a rotor 70a and a stator 70b. The rotor 70a has a generally annular shape extending about the axis A and is carried by a support element 72 which itself has a generally annular shape.

[0092] In the example shown, the support element 72 comprises a cylindrical wall 72a surrounded by the rotor 70a and attached to the internal periphery of the latter. The upstream end of this wall 72a is connected on the one hand to a radially internal annular flange 72b for attachment to the fan disc 32a, and on the other hand, to an external annular rim 72c.

[0093] The rim 72c comprises an internal cylindrical surface 72d bearing on an external cylindrical surface of the fan 14 so as to ensure the centring of the rotor 70a. The rim 72c further comprises external annular wipers 72e of a labyrinth type seal.

[0094] The stator 70b also has a generally annular shape and is carried by an annular support element 74 formed by the assembly of two annular and coaxial parts. The assembly comprising the stator 70b and its support element 74 forms an electric module M within the meaning of the invention.

[0095] The element 74 comprises: [0096] an annular support 75a that surrounds and covers at least one portion of the stator 70b and is attached to the external periphery of the stator, and [0097] an annular cover 75b that surrounds and covers at least one portion of the support 75a.

[0098] The cover 75b comprises a surface 74a that internally defines the flow duct of the gas flow F, between the fan 14 and the splitter nose 34. This surface 74a is thus swept by the gas flow F.

[0099] One of the particularities of this installation lies in the fact that the electric machine 70 and in particular its stator 70b is located as close as possible to the main flow F after passing through the fan 14. This allows on the one hand to have an electric machine with a large diameter and thus with a higher potential power than the technologies proposed so far, and on the other hand to have a machine which is cooled by the flow F. Advantageously, the thermal rejections of the electric machine are dissipated by this cooling.

[0100] For this purpose, the surface 74a swept by the flow F preferably has an aerodynamic profile, as shown in the drawing. The element 74 ensures the heat exchange by thermal conduction between the stator 70b and the flow F.

[0101] The cover 75b comprises at its upstream end an internal cylindrical surface 75ba which is for example coated with an abradable layer, and which cooperates with the aforementioned wipers 72e.

[0102] The downstream end of the cover 75b is axially aligned with the shroud 64, an upstream peripheral edge 64a of which is axially engaged in an annular groove 74b of the cover 75b. This groove 74b is oriented axially downstream. The engagement of the upstream edge 64a of the shroud 64 in the groove 74b ensures an overlap and thus avoids a step in the duct which would disturb the flow F.

[0103] In the vicinity of its downstream end in the example shown, the cover 75b comprises orifices 75bb for mounting screws 77. The orifices 75bb are oriented substantially radially with respect to the axis A and are preferably evenly distributed around this axis.

[0104] The cover 75b further comprises an internal cylindrical mounting surface 75bc fitted to an external cylindrical surface 75aa of the support 75a. The cover 75b is intended to be mounted on the support 75a by axially translating and sliding the cover on the support, and more particularly the surfaces 75bc, 75aa on top of each other, as will be described in more detail in the following.

[0105] The support 75a comprises a cylindrical wall 75ab connected at its downstream end to an annular flange 76 for attachment to the bearing support 42 or to the flange 40a of the inlet casing 40.

[0106] The wall 75ab comprises blind holes 75ab at its downstream end that are threaded and aligned with the orifices 75bb for the passage and screwing in of the screws 77.

[0107] The flange 76 is generally U-shaped in axial cross-section with the opening oriented radially outward. In the example shown, the flange 76 is attached by screws to a flange on bearing support 62 and to the flange 40b on the inlet casing.

[0108] The flange 76 thus defines an annular space X that serves for the electrical connection of the stator 70b. The space X is delimited externally by the shroud 64. It is thus understood that in the absence or disassembling of this shroud 64, one can access to the space X.

[0109] The stator 70b is connected by electrical connection means to a power electronic circuit 78 which is located between the two envelopes 37b, 39 and thus in the gas generator 12 (FIG. 2).

[0110] The means for electrically connecting the stator 70b to the circuit 78 may comprise harnesses 82 and one or more electrically conductive rigid bars 80.

[0111] In a preferred embodiment of the invention, the stator 70b is connected by a first electrical harness to one end of a bar 80, the opposite end of which is connected by a second electrical harness to the circuit 78. In this case, the cross-section of the core 82a of each harness 82 is preferably the same or close to the cross-section of the body 80a of the bar 80. The cross-section of the bar 80 and in particular of its body 80a is preferably constant over the entire length of the bar. FIG. 5 allows to show an end 80c of the bar 80 located in the space X and intended to be connected to the stator 70b by a harness 82.

[0112] FIG. 3 allows to see that the shrouds 64, 66, and 68 and the IGV 52 here form a one-piece annular assembly that is also visible in FIG. 5.

[0113] The shroud 64 is thus integral with the radially internal ends of the IGV 52. Its upstream end comprises the edge 64a engaged in the groove 74b, and its downstream end comprises an edge 64b bearing axially against a cylindrical shoulder of the inlet casing 40 or its flange 40b.

[0114] The shroud 66 is integral with the radially external ends of the IGV 52. Its upstream end is connected to the upstream end of the shroud 68 to form the splitter nose 34, as discussed above. The downstream ends of the shrouds 66, 68 are also connected together to form an annular flange 79 for attachment by screws or the like to the inlet casing 40.

[0115] FIGS. 4a through 4d and 5 illustrate steps in a maintenance method for the turbomachine 10.

[0116] In the order shown for the steps illustrated in FIGS. 4a to 4d, these steps allow the disassembling of the electric module M. It is understood that it is sufficient to repeat these steps in the reverse order to carry out an assembly or reassembly of the module

[0117] Prior to the steps illustrated, the fan module including the fan 14 and the rotor 75a of the electric machine 70 is removed by translating axially upstream.

[0118] In the first step illustrated in FIGS. 4a and 4b, the screws 77 for attaching the cover 75b to the support 75a are unscrewed and removed. This allows the cover 75b to be disengaged from the support 75a.

[0119] The cover 75b can then be removed by translating axially upstream (FIGS. 4c and 5).

[0120] The assembly formed by the shrouds 64-68 and the IGV 52 is then removed by axial translation upstream (FIGS. 4d and 5).

[0121] The next step, not shown, is to disengage the flange 76 from the bearing support 62 and the inlet casing 40, so that the module M can be removed from which the cover 75b has already been removed.

[0122] FIG. 6 shows a cross-section of an electric harness 82 that is generally circular in shape and comprises a conductive core 82a formed by a strand of wires and an insulating external sheath 82b. FIG. 7 shows an example of an embodiment of a bar 80, which comprises a conductive body 80a preferably having a polygonal shape and for example rectangular in cross-section. The bar 80 further comprises an insulating external sheath 80b. [0123] The present invention allows to provide many advantages: [0124] the bar 80 allows, contrary to a harness, very large bending radii; this is essential in the environment concerned; this allows to limit the thickness of the splitter nose 34 to a thickness close to that of the bar 80; moreover, the “twistable” profile of the bar allows to adapt according to the area crossed: radial position (in the plane P1) to enter the IGV 52 or the casing arm, and axial position (in the plane P2) to cross the inlet casing 40 at the level of an OGV 44; [0125] the bar 80 is rigid, so there is no risk of vibrations due to too much flexibility and therefore no need for specific support in the arms of the inlet casing 40; [0126] the path described above is compatible with all the oil auxiliaries circulating in the arms of the inlet casing 40; moreover, the walls of the inlet casing 40, and in particular the walls 40a and 42b, isolate the bar 80 from these oil auxiliaries, which limits the risk of fire; and [0127] the modularity linked to the ease of assembly/disassembly of the bar 80 by removing only a few parts of the turbomachine.

[0128] This invention could be applied to any turbomachine equipped with an electric machine upstream of a structural casing such as an inlet casing or other.