Bearing support designed to support an electrical machine without generating additional vibration modes

Abstract

The invention relates to a turbomachine subassembly comprising: – an inter-compressor housing (17) and a bearing support (18) carried by the inter-compressor housing (17); – a high-pressure body (11) and a low-pressure body (9); – an electric machine (M) comprising an electric stator (S) carried by the bearing support (18) and an electric rotor (R) surrounding the electric stator (S) while being carried by the high-pressure body (11); – a downstream bearing (22) carried by the inter-compressor housing (17) to guide the rotation of the high-pressure body (11); – an upstream bearing (26) carried by the bearing support (18) to guide the rotation of the low-pressure body (9); – an additional bearing (39) carried by the bearing support (18), being located longitudinally between the upstream bearing (26) and the downstream bearing (22) to guide the rotation of the low-pressure body (9). Figure for the abbreviation: Figure 2.

Description

Title of the invention: Bearing support arranged to carry an electric machine without generating additional vibration modes Technical field

[0001] The invention relates to the integration of an electrical machine, which may be for example an alternator or a motor, in a turbojet. STATE OF THE PRIOR ART

[0002] Taking into account in particular the growth of electrically powered systems, the aeronautical field is studying the integration of electrical machines within a turbojet, in particular to design a hybrid engine solution, these machines providing a motor and / or generator function.

[0003] Such a solution aims to use fossil fuel energy and electrical energy in order to drive the propulsion part of the engine and to electrically power certain functions of the engine and / or the aircraft that this engine equips.

[0004] In practice, such integration encounters multiple problems, since the compactness of the arrangement of the components present within existing motors leaves little space for the addition of an electrical machine, and it also represents an addition of rotating mechanical masses which is detrimental to the vibration modes of the motor.

[0005] In this context, the object of the invention is to provide a solution for integrating an electric machine into a motor having an acceptable impact in terms of vibration modes of the motor. Statement of the invention

[0006] To this end, the invention relates to a turbomachine subassembly comprising:

[0007] - an inter-compressor casing and a bearing support carried by the inter-compressor casing compressors;

[0008] - a low pressure body, and a high pressure body extending mainly in downstream of the bearing support;

[0009] - an electric machine comprising an electric stator carried by the support of bearing and an electric rotor surrounding the electric stator while being carried by the high pressure body;

[0010] - a downstream bearing carried by the inter-compressor casing to guide the rotation of the high pressure body;

[0011] - an upstream bearing carried by the bearing support to guide the body in rotation low pressure;

[0012] - an additional bearing carried by the bearing support, being located between the upstream bearing and the downstream bearing to guide the high pressure body in rotation.

[0013] With this arrangement, the additional rotating mass constituted by the rotor of the electrical machine, which is likely to have an unbalance, is supported essentially by the additional bearing, so as to limit the occurrence of additional vibration modes which may be generated by this electrical machine.

[0014] The invention also relates to a subassembly thus defined, in which the bearing support comprises a body including a cylindrical internal skirt extending downstream thereof, and in which the additional bearing is carried by this cylindrical internal skirt.

[0015] The invention also relates to a subassembly thus defined, in which the downstream bearing is a ball bearing, and in which the upstream bearing and the additional bearing are roller bearings.

[0016] The invention also relates to a subassembly thus defined, comprising an internal lubrication enclosure delimited by the bearing support and enclosing the upstream bearing and the additional bearing.

[0017] The invention also relates to a subassembly thus defined, in which the bearing support comprises an upstream shell carrying a segmented radial seal to form an upstream sealing barrier for the internal enclosure.

[0018] The invention also relates to a subassembly thus defined, in which the high pressure body comprises a bell forming a downstream sealing barrier for the internal enclosure.

[0019] The invention also relates to a subassembly thus defined, comprising a first lubrication nozzle carried by the bearing support and protruding into the internal enclosure, this first nozzle being oriented towards the additional bearing in order to lubricate it.

[0020] The invention also relates to a subassembly thus defined, comprising a second lubrication nozzle carried by the bearing support and protruding into the internal enclosure, this second nozzle being oriented towards axial channels of the high pressure body to convey lubricating oil to the downstream bearing.

[0021] The invention also relates to a turbomachine comprising a subassembly thus defined. Brief description of the drawings

[0022] [Fig.l] is a longitudinal sectional view of a dual-flow twin-spool turbojet engine;

[0023] [Fig.2] is a longitudinal sectional view of the bearing support according to the invention with its environment in a turbojet;

[0024] [Fig. 3] is a partial longitudinal sectional view showing the lubrication of the upstream bearing and the lubrication of the additional bearing.

[0025] DETAILED DESCRIPTION OF PARTICULAR EMBODIMENTS

[0026] In [Fig.l], a turbojet 1 extending along an axis of rotation AX comprises at its upstream end AM an inlet sleeve through which the air is admitted to pass through a low pressure compressor 2 before being split into a central primary flow F1 and a secondary flow F2 surrounding the primary flow.

[0027] These flows circulate in the turbojet 1 from upstream AM to downstream AV, this turbojet being delimited externally by an external structure 3 forming its fairing and externally delimiting the secondary flow F2.

[0028] The primary flow is then compressed in a high-pressure compressor 4 before arriving in a combustion chamber 5, after which it is expanded through a high-pressure turbine 6 and a low-pressure turbine 7 before being discharged to the rear. The secondary flow is directed directly to the rear.

[0029] As visible in [Fig.l], the low pressure compressor 2 and the low pressure turbine 7 comprise moving blades carried by a rotating assembly constituting a low pressure body 9. Similarly, the high pressure compressor 4 and the high pressure turbine 6 comprise moving blades carried by the same high pressure body 11, which surrounds the low pressure body while being independent in rotation thereof, these two bodies rotating around a longitudinal axis AX.

[0030] This engine comprises upstream of the low pressure compressor 2 an inlet casing 12, comprising radial arms by which it is secured to the external structure 3. An upstream bearing 13 mounted in this inlet casing 12 carries in rotation an upstream part of the low pressure body 9.

[0031] This inlet casing 12 is extended upstream by a fixed cone 16, directing the incoming flow around the central part comprising the high and low pressure bodies, minimizing the induced aerodynamic losses.

[0032] This engine comprises between the low pressure compressor 2 and the high pressure compressor 4 an inter-compressor casing 17, comprising radial arms by which it is secured to elements of the external structure 3. An inter-compressor bearing support 18 mounted in this inter-compressor casing 17 carries in rotation an upstream part of the low pressure body 9 and an upstream part of the high pressure body 11.

[0033] As can be seen more clearly in [Fig.2], the high pressure compressor 4 comprises fixed blades 19 rigidly secured to the structure 3 and rotating blades 21 carried by the high pressure body 11.

[0034] This high pressure body 11 which extends mainly downstream of the bearing support 18 has its upstream part supported by a downstream bearing 22, that is to say located downstream of the bearing 18, this downstream bearing 22 being carried by a fixed internal flange 23 which is ri firmly secured to a downstream part 24 of the inter-compressor casing 17 of which it is thus part.

[0035] The bearing support 18 has a shape of revolution around the longitudinal axis AX, and it carries in its central part an upstream portion of the low pressure body 9 by means of an upstream bearing 26 to guide it in rotation.

[0036] This support 18 carries upstream of the bearing 26 a segmented radial seal 27 which forms a sealing barrier with the low pressure body 9, to delimit an internal enclosure E enclosing the upstream bearing 26. A circulation of pressurized air carrying an oil mist is ensured in the internal enclosure E, which in particular makes it possible to lubricate the bearing 26 and to ensure that external air does not enter this enclosure.

[0037] The support 18 is a revolution element comprising a main body 28 and an upstream ferrule 29, which are revolution elements around the axis AX, the ferrule being rigidly secured to the upstream face of the body 28.

[0038] This body 28 comprises an external flange 31 by which it is fixed to an upstream internal flange 32 of the casing 17, and an external cylindrical skirt 33 extending downstream and by the end of which it is secured to a downstream internal part 24 of the casing 17. This body 28 also comprises an internal skirt 34, also cylindrical, which extends downstream inside the skirt 33.

[0039] In its downstream portion, this body 28 carries an electric stator S which is surrounded by an electric rotor R carried by the high pressure body 11 to form an electric machine M. A cover of revolution 36 covers the stator S by being attached to a downstream part of the body 28, to delimit with the cylindrical internal skirt 34 an enclosure for this stator which makes it possible to establish around this stator S a circulation of cooling oil.

[0040] The rotor R is carried by a rotating bell 37 rigidly secured to the high-pressure body 11 by a flange 38. This bell 37 extends upstream in the body 28, radially between the external skirt 33 and the stator S. This bell 37, which is rotating, thus constitutes a sealing barrier for the downstream portion of the internal enclosure E.

[0041] This enclosure E is thus delimited externally by the body 28, it is delimited internally by the low pressure body 9 and by the high pressure body 11 which extends in its extension, and it has its upstream end closed by the segmented radial seal 27, and its downstream end closed by the bell 37.

[0042] According to the invention, the bearing comprises an additional rolling bearing 39 carried by the skirt 34 to provide additional rotational guidance of the upstream end of the high-pressure body 11, at the level of the electric rotor R, so as to limit the vibration modes that can be generated by this electric rotor R.

[0043] As visible in [Fig.2], this additional bearing 39 is located longitudinally between the upstream bearing 26 and the downstream bearing 22, being carried more precisely at the level of the downstream end of the skirt 34.

[0044] Thanks to this additional bearing 39, any unbalance of the electric rotor R or of the bell 37, which rotates at the speed of the high pressure body 11 which is a high speed, has a very low impact on the vibration modes of the motor and of the high pressure body 11.

[0045] This additional bearing 39 is advantageously a roller bearing to ensure guidance only in rotation of the upstream end of the high pressure body 11, as opposed to the downstream bearing 22 which is advantageously a ball bearing so as to guide the body 11 in rotation and to transfer the longitudinal forces undergone by this body 11 towards the inter-compressor casing 17.

[0046] The additional bearing 39 being located between the upstream bearing 26 and the downstream bearing 22, it extends inside the enclosure E, which ensures its lubrication.

[0047] As can be seen more clearly in [Fig. 3], the bearings 39 and 22 are lubricated by means of a first and a second nozzle 40 and 41 carried by the body 28 of the support 18. These two nozzles 40, 41 protrude from the cylindrical internal face of the skirt 34, radially towards the axis AX, to open near the additional bearing 39.

[0048] These two nozzles are supplied by channels (not shown) which are formed in the body 28, and which are supplied with lubricating oil via radial arms of the inter-compressor casing 17.

[0049] The first nozzle 40 opens opposite an upstream face of the additional bearing 39, to spray oil directly onto the rollers or balls of this bearing 39, as illustrated by the arrow in broken lines protruding from this nozzle, in [Fig.3].

[0050] As visible in [Fig.2], the body 11 has a tubular upstream end 42 surrounded by the additional bearing 39 and by which this additional bearing guides the high pressure body 11 in rotation. This end 42 is extended upstream by an upstream extension 43 surrounding the downstream end of the low pressure body 9, which carries wipers, so as to form a sealing barrier between the low pressure body 9 and the high pressure body 11, which jointly delimit the interior of the enclosure E.

[0051] The upstream end 42 is provided with axial channels 44 arranged to convey the oil collected in the internal enclosure E to the downstream bearing 22 in order to lubricate it. These channels have inlet openings opening into the upstream face of this end 42 at positions located radially outside the upstream extension 43, and discharge openings located on the internal face of the end 42 (downstream of the inlet openings).

[0052] Additionally, this end 42 is extended upstream by a collector 46 having the shape of a conical portion narrowing upstream and the base of which extends around the inlet openings of the channels 44.

[0053] As visible in [Fig. 3], the second nozzle 41 is oriented towards the inlet of the collector 46 (i.e. towards its upstream mouth) so as to cause oil to enter this collector 46. Due to the rotation of the high-pressure body 11, the oil supplied by the second nozzle 41 is centrifuged on the internal face of the collector 46, then due to the conical shape of the latter, it is naturally directed downstream to be admitted into the channels 44.

[0054] After passing through the channels 44, the oil ends up on the internal face of the high-pressure body 11 and continues its progression downstream on this internal face. As visible in [Fig. 3], the high-pressure body has radial through holes 47 located at the level of the downstream bearing 22. The oil having progressed along the internal face of this high-pressure body 11 is thus recovered in the radial holes 47 to lubricate the balls of the downstream bearing 22.

Claims

Claims

1. Turbomachine subassembly comprising: - an inter-compressor casing (17) and a bearing support (18) carried by the inter-compressor casing (17); - a low-pressure body (9), and a high-pressure body (11) extending mainly downstream of the bearing support (18); - an electrical machine (M) comprising an electric stator (S) carried by the bearing support (18) and an electric rotor (R) surrounding the electric stator (S) while being carried by the high-pressure body (11); - a downstream bearing (22) carried by the inter-compressor casing (17) to guide the high-pressure body (11) in rotation; - an upstream bearing (26) carried by the bearing support (18) to guide the low-pressure body (9) in rotation. - an additional bearing (39) carried by the bearing support (18), being located between the upstream bearing (26) and the downstream bearing (22) to guide the high pressure body (11) in rotation.

2. Subassembly according to claim 1, in which the bearing support (18) comprises a body (28) including a cylindrical internal skirt (34) extending downstream thereof, and in which the additional bearing (39) is carried by this cylindrical internal skirt (34).

3. Subassembly according to claim 1 or 2, in which the downstream bearing (22) is a ball bearing, and in which the upstream bearing (26) and the additional bearing (39) are roller bearings.

4. Subassembly according to claim 1, comprising an internal lubrication enclosure (E) delimited by the bearing support (18) and enclosing the upstream bearing (26) and the additional bearing (39).

5. Subassembly according to claim 4, in which the bearing support (18) comprises an upstream ferrule (29) carrying a segmented radial seal (27) to form an upstream sealing barrier for the internal enclosure (E).

6. Subassembly according to claim 4, in which the high pressure body (11) comprises a bell (37) forming a downstream sealing barrier for the internal enclosure (E).

7. Subassembly according to claim 4, comprising a first lubrication nozzle (40) carried by the bearing support (18) and protruding into the internal enclosure (E), this first nozzle being oriented towards the additional bearing (39) in order to lubricate it.

8. Subassembly according to claim 7 comprising a second lubrication nozzle (41) carried by the bearing support (18) and protruding into the internal enclosure (E), this second nozzle (41) being oriented towards axial channels (44) of the high pressure body (11) to convey lubricating oil to the downstream bearing (22).

9. Turbomachine comprising a subassembly according to one of the preceding claims.

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