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 support an electrical 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, into a turbojet engine. PREVIOUS STATE OF THE ART

[0002] In view of the rise of electrically powered systems, the aeronautical field is studying the integration of electric machines within a turbojet engine, in particular to design a hybrid engine solution, these machines provide a motor and / or generator function.

[0003] Such a solution aims to use the fossil energy of the fuel and electrical energy to drive the propulsive 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, given that the compactness of the arrangement of components within existing motors leaves little space for the addition of an electric machine, and that it also represents an addition of rotating mechanical masses which is detrimental to the vibrational modes of the motor.

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

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

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

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

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

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

[0013] With this arrangement, the additional rotating mass that constitutes the rotor of the electric machine, which is likely to have an imbalance, is supported essentially by the additional bearing, so as to limit the appearance of additional vibration modes that may be generated by this electric machine.

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

[0015] The invention also relates to a sub-assembly 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 sub-assembly thus defined, comprising an internal lubrication chamber delimited by the bearing support and enclosing the upstream bearing and the additional bearing.

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

[0018] The invention also relates to a sub-assembly 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 sub-assembly thus defined, comprising a first lubrication jet carried by the bearing support and protruding into the internal enclosure, this first jet being oriented towards the additional bearing in order to lubricate it.

[0020] The invention also relates to a sub-assembly 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 sub-assembly thus defined. Brief description of the drawings

[0022] The [Fig.1] is a longitudinal cross-sectional view of a twin-spool, twin-flow turbojet engine;

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

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

[0025] DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

[0026] In [Fig.1], a turbojet 1 extending along an axis of rotation AX has upstream AM an inlet sleeve through which air is admitted to pass through a low-pressure compressor 2 before being split into a central primary flow Fl 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 hull and externally delimiting the secondary flow F2.

[0028] The primary flow is then compressed in a high-pressure compressor 4 before entering 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, on the other hand, is directed directly to the rear.

[0029] As seen in [Fig.1], the low pressure compressor 2 and the low pressure turbine 7 have movable blades carried by a rotating assembly constituting a low pressure body 9. Similarly, the high pressure compressor 4 and the high pressure turbine 6 have movable blades carried by the same high pressure body 11, which surrounds the low pressure body while being independent in rotation of the latter, these two bodies rotating around a longitudinal axis AX.

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

[0031] This inlet housing 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 includes, between the low-pressure compressor 2 and the high-pressure compressor 4, an inter-compressor housing 17, having 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 housing 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 vanes 19 rigidly attached to the structure 3 and rotating vanes 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 securely attached to a downstream part 24 of the inter-compressor housing 17 of which it thus forms a 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 containing the upstream bearing 26. A circulation of pressurized air carrying an oil mist is ensured in the internal enclosure E, which makes it possible in particular 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 about the axis AX, the ferrule being rigidly fixed to the upstream face of the body 28.

[0038] This body 28 has an external flange 31 by which it is fixed to an upstream internal flange 32 of the housing 17, and an external cylindrical skirt 33 extending downstream and by the end of which it is secured to an internal downstream part 24 of the housing 17. This body 28 also has 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 inner skirt 34 an enclosure for this stator which allows to establish around this stator S a circulation of cooling oil.

[0040] The rotor R is itself supported by a rotating bell 37 rigidly attached to the high-pressure body 11 by a flange 38. This bell 37 extends upstream in the body 28, radially between the outer skirt 33 and the stator S. This rotating bell 37 thus constitutes a sealing barrier for the downstream portion of the inner 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 continuation, and it has its upstream end closed by the segmented radial joint 27, and its downstream end closed by the bell 37.

[0042] According to the invention, the bearing includes an additional 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 vibrational modes that can be generated by this electric rotor R.

[0043] As can be seen 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 downstream end of the skirt 34.

[0044] Thanks to this additional bearing 39, a possible imbalance 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 rotational guidance only 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 suffered by this body 11 to the inter-compressor housing 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 jet 40 and 41 carried by the body 28 of the support 18. These two jets 40, 41 protrude from the cylindrical inner 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 housing 17.

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

[0050] As seen in [Fig.2], the body 11 has an upstream tubular 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 flaps, so as to form a sealing barrier between the low-pressure body 9 and the high-pressure body 11, which together 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 ports opening into the upstream face of this end 42 at positions located radially outside the upstream extension 43, and discharge ports located on the internal face of the end 42 (downstream of the inlet ports).

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

[0053] As can be seen in [Fig.3], the second nozzle 41 is directed towards the inlet of the manifold 46 (i.e. towards its upstream mouth) so as to introduce oil into this manifold 46. Due to the rotation of the high-pressure body 11, the oil supplied by the second nozzle 41 is centrifuged to the inner face of the manifold 46, and 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 reaches the inner face of the high-pressure body 11 and continues its downstream progression along this inner face. As shown in [Fig. 3], the high-pressure body has radial through holes 47 located at the downstream bearing 22. The oil, having progressed along the inner face of this high-pressure body 11, is thus collected in the radial holes 47 to lubricate the balls of the downstream bearing 22.

Claims

Demands

1. Turbomachine subassembly comprising: - an inter-compressor housing (17) and a bearing support (18) carried by the inter-compressor housing (17); - a low-pressure body (9), and a high-pressure body (11) extending predominantly downstream of the bearing support (18); - 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) for guiding the rotation of the high-pressure body (11); - an upstream bearing (26) carried by the bearing support (18) for guiding the rotation of the low-pressure body (9). - 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 rotation of the high-pressure body (11).

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

3. Subassembly according to claim 1 or 2, wherein the downstream bearing (22) is a ball bearing, and wherein 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, wherein the bearing support (18) comprises an upstream ferrule (29) carrying a segmented radial seal (27) to form an upstream sealing barrier for the inner enclosure (E).

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

7. Subassembly according to claim 4, comprising a first lubrication nozzle (40) carried by the bearing support (18) and protruding into the inner 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 inner 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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