Lubrication system common to two chambers of a turbomachine

Abstract

This application relates to a lubrication system for a turbomachine (1), extending about a longitudinal axis (X) and comprising: - a first oil lubrication chamber (10); - a second oil lubrication chamber (20); - a connecting channel (60) adapted to fluidly connect the first chamber (10) and the second chamber (20); - a turbomachine shaft bearing (15) arranged to be lubricated in the first chamber (10); - an electric machine shaft bearing (22) arranged to be lubricated in the second chamber (20); and - a pump (23) configured to extract oil from the second chamber (20) and send it into the first chamber (10) via the connecting channel (60). Figure for the abstract: Fig. 6

Description

Title of the invention: Lubrication system common to two housings of a turbomachine technical field

[0001] This application relates to the field of aircraft turbomachinery, and more particularly to the field of lubrication systems for turbomachine components. TECHNOLOGICAL BACKGROUND

[0002] An aircraft typically comprises at least one turbomachine for propulsion. The turbomachine may be a turbojet or a turboprop. The turbomachine typically comprises, from upstream to downstream in the direction of flow through the turbomachine, a fan, a compressor, a combustion chamber, a turbine, and an exhaust nozzle.

[0003] A turbojet engine can be a turbofan engine, in which the mass of air sucked in by the fan is divided into a primary flow, which passes through at least one compressor, the combustion chamber and at least one turbine, and a secondary flow, which is concentric with the primary flow.

[0004] For example, the turbomachine may comprise a low-pressure compressor and a high-pressure compressor, and a high-pressure turbine and a low-pressure turbine. The high-pressure turbine drives the high-pressure compressor via a high-pressure shaft, and the low-pressure turbine drives the low-pressure compressor via a low-pressure shaft. The low-pressure turbine may also drive the fan either directly via the low-pressure shaft or via a gearbox located between the low-pressure turbine and the fan, the gearbox being driven by the low-pressure shaft.

[0005] A rotary guide bearing is conventionally mounted between two turbomachine components with different rotational speeds, i.e., between two turbomachine components that rotate relative to each other during turbomachine operation. For example, the high-pressure shaft and the low-pressure shaft, or the low-pressure shaft and a fixed housing of the turbomachine, rotate relative to each other. Thus, a guide bearing can be positioned between the high-pressure shaft and the low-pressure shaft of the turbomachine, and / or between the low-pressure shaft and a fixed housing of the turbomachine. The roller guide bearing comprises a bearing element retained between two rings that form raceways for the bearing element and enclose the bearing element.

[0006] The various guide bearings of the turbomachine are located in at least one lubrication chamber. Oil is supplied to the lubrication chamber(s) via a supply circuit, in particular through an auxiliary element in the form of a supply duct formed in an arm of a turbomachine housing. The oil provides lubrication and cooling for certain turbomachine components, such as the guide bearing's rolling element, as well as damping of vibrations generated by the rotation of the shafts and bearings. The oil is then drained and recovered via a recovery circuit, in particular through an auxiliary element in the form of a recovery duct passing through an arm of a turbomachine housing. The recovered oil is cooled and then reused, the oil supply operating in a closed circuit.

[0007] Some turbomachines include an electric machine. For example, an unshod turbomachine with two counter-rotating propellers may include an electric machine. The electric machine may be substantially annular and extend around the longitudinal axis of the turbomachine. The electric machine allows for the recovery or supply of energy, for example, for electric hybridization.

[0008] The electric machine may have its own rotary guide bearing. The electric machine bearing may be integrated into its own lubrication chamber, particularly for reasons of space or maintainability that prevent the electric machine bearing from being placed in an existing lubrication chamber of the turbomachine. The electric machine lubrication chamber is supplied with oil so as to lubricate the electric machine bearing and, where applicable, to cool components of the electric machine.

[0009] The lubrication chamber of the electric machine must therefore be equipped with its own lubrication system. This implies adding auxiliary elements in the form of a supply line and a return line specific to the electric machine chamber within the crankcase arms, so as to allow oil circulation within the electric machine chamber. These additional auxiliary elements require enlarging the existing crankcase arms and / or adding arms to the crankcase. The efficiency of the turbomachine is thereby reduced.

[0010] For example, a low-pressure turbine of a turbomachine may comprise a fixed casing, also called an exhaust casing, and a rotor that is rotationally fixed to the low-pressure shaft of the turbomachine. The rotor of the low-pressure turbine comprises a rotor blade wheel fixed to a rotor disc. The rotor of the low-pressure turbine is mounted on a low-pressure journal. The low-pressure journal is mounted on the low-pressure shaft, for example by means of splines, in order to drive the low-pressure shaft in rotation. A guide bearing is Mounted between the low-pressure journal, which is rotationally fixed to the low-pressure shaft, and the fixed exhaust housing, the guide bearing is located in a first lubrication chamber that surrounds the low-pressure shaft at the turbine. A second, separate lubrication chamber may include an electric motor. The exhaust housing comprises an inner hub, an outer shell extending around the hub, and the shell and hub defining a portion of the primary flow path at the low-pressure turbine. The exhaust housing further includes feed arms adapted to connect the hub to the shell. The feed arms allow passage of auxiliary components of the lubrication system, in particular the supply and return lines of the first chamber, and the supply and return lines of the second chamber.Therefore, several ducts must be implemented in the same crankcase arm, which leads to enlarging the existing arms, or increasing the number of crankcase arms. This degrades the turbomachine's efficiency. GENERAL STATEMENT

[0011] One objective of the present application is to propose a lubrication system for a turbomachine that improves the efficiency of the turbomachine.

[0012] Another objective of the present application is to propose a lubrication system for a turbomachine that allows oil to be supplied and evacuated from two separate chambers, with limited complexity and cost.

[0013] Another objective of the present application is to propose a lubrication system for a turbomachine that allows oil to be supplied and discharged from two separate chambers, with a limited number of service elements passing through arms of a lubrication system housing and / or a limited number of arms of a lubrication system housing and / or limited dimensions of arms of a lubrication system housing.

[0014] To this end, according to a first aspect, a lubrication system for a turbomachine is proposed, said lubrication system extending around a longitudinal axis and comprising: - a first oil lubrication chamber extending around the longitudinal axis; - a second oil lubrication chamber extending around the longitudinal axis; - a suitable connecting channel to fluidly connect the first enclosure and the second enclosure; - a turbomachine shaft bearing extending around the longitudinal axis and arranged to be lubricated in the first enclosure; - an electric machine shaft bearing arranged to be lubricated in the second pregnant; and - a pump configured to extract oil from the second chamber and send it into the first chamber via the connecting channel.

[0015] Some preferred but non-limiting features of the lubrication system according to the first aspect are the following, taken individually or in combination:

[0016] - the pump is housed in the second enclosure and is supplied with electrical energy by the electric machine; - The lubrication system also includes: - a fixed housing comprising an internal hub, an external ferrule extending around the internal hub, a feed arm connecting the internal hub to the external ferrule, and a recovery arm connecting the internal hub to the external ferrule, wherein the feed arm comprises an internal housing for the passage of a feed service element and / or wherein the recovery arm comprises an internal housing for the passage of a recovery service element; and - a rotor mounted to rotate freely relative to the casing around the longitudinal axis, the turbomachine shaft bearing being configured to guide the rotor in rotation relative to the casing; - the lubrication system includes a supply service element corresponding to an oil supply conduit which extends through the internal housing of the supply arm to supply oil to the first chamber and the second chamber, the oil supply conduit has an arm portion which extends through the internal housing of the supply arm and which is extended by a first bifurcation portion and a second bifurcation portion, the first bifurcation portion being fluidly connected to a supply port of the first chamber, and the second bifurcation portion being fluidly connected to a supply port of the second chamber; - the lubrication system further includes a recovery service element corresponding to an oil recovery conduit which extends through the internal housing of the recovery arm and is fluidly connected to a recovery orifice of the first enclosure so as to allow oil to be evacuated outside the first enclosure; - the lubrication system is configured so that the oil can flow by gravity out of the first enclosure and / or the second enclosure; - The lubrication system also includes: - a first pressurized air cavity arranged around the first enclosure, and one or more sealing gaskets arranged at the interface between the first enclosure and first cavity, so as to prevent oil from flowing from the first enclosure into the first cavity; and / or - a second pressurized air cavity arranged around the second enclosure, and one or more sealing gaskets arranged at the interface between the second enclosure and the second cavity, so as to prevent oil from escaping from the second enclosure into the second cavity; - the first enclosure includes an annular piece provided with at least one oil circulation orifice, so as to allow oil to circulate in the first enclosure through at least one oil circulation orifice.

[0017] According to a second aspect, the present application relates to a turbine of a tur-bomachine comprising a lubrication system according to the first aspect.

[0018] The turbine can be a low-pressure turbine. The fixed housing of the lubrication system can correspond to the exhaust housing of the low-pressure turbine, and the rotor of the lubrication system can correspond to the rotor of the low-pressure turbine.

[0019] According to a third aspect, the present application relates to a turbomachine comprising a lubrication system according to the first aspect. The turbomachine may include a turbine, in particular a low-pressure turbine, according to the second aspect.

[0020] The turbomachine can be a twin-body turbomachine.

[0021] According to a fourth aspect, the present application relates to an aircraft comprising at least one turbomachine according to the third aspect. DESCRIPTION OF THE FIGURES

[0022] Other features, purposes and advantages will become apparent from the following description, which is purely illustrative and not limiting, and which should be read in conjunction with the accompanying drawings on which:

[0023] Fig. 1 is a schematic axial cross-sectional view of an aircraft propulsion assembly.

[0024] The [Fig.2] is a partial schematic axial cross-sectional view of a low-pressure turbine of a turbomachine.

[0025] Fig. 3 is a partial schematic perspective view of a supply arm and a supply servicing element of a lubrication system according to one embodiment.

[0026] Fig. 4 is a partial schematic axial cross-sectional view of a lubrication system according to one embodiment, at the level of an oil supply to the chambers of the lubrication system.

[0027] Fig. 5 is a partial schematic axial cross-sectional view of a lubrication system according to one embodiment, at the level of an oil recovery from the lubrication system enclosures.

[0028] Fig. 6 is a partial schematic axial cross-sectional view of the lubrication system of figures 4 and 5. DETAILED DESCRIPTION

[0029] In the present application, upstream and downstream are defined with respect to the normal flow direction of the gas through the operating turbomachine 1, with air flowing through the turbomachine 1 from upstream to downstream. The turbomachine axis L corresponds to an axis of rotation of the turbomachine 1, in particular to an axis of rotation of a turbine of the turbomachine 1. A radial axis is an axis perpendicular to and passing through the turbomachine axis L. A circumferential axis is an axis perpendicular to and not passing through the turbomachine axis L. A longitudinal direction, respectively radial or circumferential, corresponds to the direction of the turbomachine axis L, respectively radial or circumferential. The longitudinal, radial, and circumferential directions are orthogonal to each other.

[0030] The terms internal and external, respectively, are used with reference to a radial direction such that the internal part or face of an element is closer to the turbomachine axis L than the external part or face of the same element.

[0031] The turbomachine 1 can be a turbojet or a turboprop. The turbomachine 1 extends around the turbomachine axis L. The turbomachine 1 can include a fan 3, at least one compressor 4, 5, a combustion chamber 6, at least one turbine 7, 8, and an exhaust gas nozzle.

[0032] In the non-limiting embodiment shown in [Fig. 1], the turbomachine 1 is a twin-spool, twin-flow turbojet engine enclosed by a nacelle 2. The turbomachine 1 comprises, from upstream to downstream, a fan 3, a low-pressure compressor 4, a high-pressure compressor 5, a combustion chamber 6, a high-pressure turbine 7, and a low-pressure turbine 8. The high-pressure turbine 7 drives the high-pressure compressor 5 via a high-pressure shaft, and the low-pressure turbine 8 drives the low-pressure compressor 4 via a low-pressure shaft. The low-pressure turbine 8 can also drive the fan 3 either directly via the low-pressure shaft or via a reduction gear disposed between the low-pressure turbine 8 and the fan 3, the reduction gear being driven by the low-pressure shaft.Compressors 4 and 5, combustion chamber 6 and turbines 7 and 8 form a gas generator. During the operation of the turbomachine 1 illustrated in [Fig. 1], an airflow enters the turbomachine 1 through an air inlet at . upstream of nacelle 2, passes through blower 3 and then splits into a central primary flow and a secondary flow. The primary flow flows in a primary flow channel Vp and passes through compressors 4 and 5, combustion chamber 6 and turbines 7 and 8, and the secondary flow flows in a secondary flow channel Vs which is concentric with the primary flow channel Vp and is radially delimited outwards by nacelle 2.

[0033] Fig. 4, Fig. 5 and Fig. 6 illustrate by way of non-limiting example a lubrication system for a turbomachine 1 according to an embodiment.

[0034] The lubrication system for a turbomachine 1 extends around a longitudinal axis X and comprises: - a first oil lubrication chamber 10 extending around the longitudinal axis X; - a second oil lubrication chamber 20 extending around the longitudinal axis X; - a connecting channel 60 adapted to fluidly connect the first enclosure 10 and the second enclosure 20; - a turbomachine shaft bearing 15 extending around the longitudinal axis X and arranged to be lubricated in the first enclosure 10; - an electrical machine shaft bearing 22 arranged to be lubricated in the second enclosure 20; and - a pump 23 configured to extract oil from the second enclosure 20 and send it into the first enclosure 10 via the connecting channel 60.

[0035] The longitudinal axis X of the lubrication system can correspond to the axis of the turbomachine L. The electric machine shaft bearing 22 can extend around the longitudinal axis X.

[0036] The lubrication system described above allows the oil recovery systems of the first chamber 10 and the second chamber 20 to be shared. The oil introduced into the second chamber 20 is reinjected into the first chamber 10 by means of the pump 23 and the connecting channel 60, thus reinjecting it into the conventional cooling circuit of the first chamber 10. The connecting channel 60 links the first chamber 10 and the second chamber 20, allowing the oil pumped out of the second chamber 20 to reach the first chamber 10.

[0037] The complexity of the lubrication system is reduced. Indeed, the lubrication system described above uses the existing oil recovery system of the first chamber 10 to recover the oil. The connecting channel 60 that connects the first chamber 10 and the second chamber 20 is a simple element to install. work, and which allows the oil present in the second enclosure 20 to be recovered and introduced into the first enclosure 10.

[0038] The lubrication system described above makes it possible to limit the number of service elements required for the lubrication of the enclosures 10, 20 of the turbomachine 1, in particular the number of service elements passing through an arm 91, 92 of a housing 83 of the lubrication system, and / or the number of arms 91, 92 of the housing 83.

[0039] The pump 23 promotes the evacuation of the oil by injecting it at a certain speed into the first chamber 10.

[0040] The first enclosure 10 and the second enclosure 20 are oil-filled enclosures. In other words, these enclosures 10 and 20 are designed to contain oil. More specifically, these enclosures 10 and 20 are designed to contain a mixture of oil and air.

[0041] The oil introduced into these enclosures 10, 20 can be used in particular for the cooling and / or lubrication of certain elements of the turbomachine 1 which are located in these enclosures 10, 20. In particular, the injected oil provides lubrication and cooling of a bearing element 153 of the turbomachine shaft bearing 15 and / or of a bearing element of the electric machine shaft bearing 22. In addition, the oil dampens the vibrations generated by the rotation of the shafts and the bearing element 153.

[0042] The enclosures 10, 20 are supplied with oil, and the oil is discharged from the enclosures 10, 20 after circulating within them. The oil can be pumped out of the enclosures 10, 20 to prevent any oil leakage. When oil is pumped out of an enclosure 10, 20, air is also pumped out. This airflow exiting the enclosure 10, 20 can be balanced by an airflow entering the enclosure 10, 20 at one or more seals located between the rotor and the stator. This airflow prevents oil leakage and thus seals the enclosure 10, 20.

[0043] The oil is pumped out of the second enclosure 20 by the pump 23 via the connecting channel 60, the oil pumped out of the second enclosure 20 being reinjected into the first enclosure 10. The oil is then pumped out of the first enclosure 10, for example via a recovery line 70 from the lubrication system.

[0044] The pump 23 can be housed in the first enclosure 10, in the second enclosure 20, or outside the two enclosures 10, 20 of the lubrication system. The pump 23 can be powered by the electric machine 22 or by an external system such as an electrical harness passing through an arm. For example, the pump 23 can be housed in the second enclosure and be powered by the electric machine 22. Thus, the complexity of the lubrication system is further reduced because the lubrication system uses the electric machine 22 already present in the turbomachine to supply the pump 23 with electrical power. Alternatively, the pump 23 can be housed in the first enclosure 10 or outside the two enclosures 10, 20, and be supplied with electrical energy by the external system.

[0045] The second enclosure 20 can be arranged downstream of the first enclosure 10. The second enclosure 20 can be adjacent to the first enclosure 10, that is, located in the immediate vicinity of the first enclosure 10. Alternatively, the second enclosure 20 can be separated from the first enclosure 10 by a certain distance and by one or more elements of the turbomachine 1, provided that the first enclosure 10 and the second enclosure 20 can be connected to each other by the connecting channel 60. The sizing of the pump 23 in the second enclosure 20 can be adapted according to the distance between the first enclosure 10 and the second enclosure 20.

[0046] As illustrated by way of non-limiting example in [Fig.5], the connecting channel 60 can open into the second enclosure 20 at a recovery port 61 of the second enclosure 20, and open into the first enclosure 10 at an additional supply port 62 of the first enclosure 10. The connecting channel 60 thus extends between the recovery port 61 of the second enclosure 20 and the additional supply port 62 of the first enclosure 10, the oil being drawn from the second enclosure 20 via the recovery port 61, circulating in the connecting channel 60 until being injected into the first enclosure 10 via the additional supply port 62.

[0047] The electric machine 22 can be substantially annular and extend around the longitudinal axis X. The electric machine 22 allows for the recovery or supply of energy, in particular for the supply of electrical energy, for example for electric hybridization. A power harness of the electric machine 22 can pass through an arm 91, 92 of the housing 83. The electric machine 22 has its own rotary guide bearing. The electric machine 22 is integrated into its own second enclosure 20, which is separate from the first enclosure 10. The oil circulating in the second enclosure 20 lubricates the shaft bearing of the electric machine 22 and, if necessary, cools components of the electric machine 22.

[0048] As illustrated by way of non-limiting example in [Fig.2], [Fig.3] and [Fig.6], the lubrication system may further include: - a fixed housing 83 comprising an internal hub 84, an external ferrule 85 extending around the internal hub 84, a feed arm 91 connecting the internal hub 84 to the external ferrule 85, and a recovery arm 92 connecting the internal hub 84 to the external ferrule 85, wherein the feed arm 91 comprises an internal housing for the passage of a feed service element and / or wherein the recovery arm 92 comprises an internal housing for the passage of a recovery service element; and - a rotor mounted movable in rotation relative to the casing 83 around the longitudinal axis X, the turbomachine shaft bearing 15 being configured to guide the rotor in rotation relative to the casing 83.

[0049] The turbomachine shaft bearing 15 can be adapted to be located in the first enclosure 10.

[0050] Thus, the dimensions of the supply arm 91 and / or the recovery arm 92 are not substantially increased compared to a lubrication system comprising a single chamber; at most, the diameter of the internal housing of the supply arm 91 and / or the recovery arm 92 is slightly increased to allow the passage of an oil flow enabling the lubrication and / or cooling of both the first chamber 10 and the second chamber 20. The number of supply arms 91 and / or recovery arms 92 is not increased compared to a lubrication system comprising a single chamber.

[0051] The inner hub 84 and the outer ferrule 85 together define a portion of the primary flow vein Vp, which can be substantially annular.

[0052] The feed arm 91 and / or the retrieval arm 92 can extend in a substantially radial direction. The feed arm 91 and / or the retrieval arm 92 can have a substantially tubular shape. The internal housing of the feed arm 91, or of the retrieval arm 92 respectively, can extend substantially radially through the feed arm 91, or through the retrieval arm 92 respectively.

[0053] The turbomachine shaft bearing 15 may include an inner race 151 rotatably fixed to the rotor, an outer race 152 rotatably fixed to the housing 83, and a rolling element 153 retained and clamped between the inner race 151 and the outer race 152. The rolling element 153 may include a plurality of rollers and / or balls. Oil circulates between the rollers and / or balls to ensure their lubrication.

[0054] As illustrated by way of non-limiting example in [Fig. 3] and [Fig. 4], the lubrication system may include a supply auxiliary element corresponding to an oil supply conduit 50 that extends through the internal housing of the supply arm 91 to supply oil to the first chamber 10 and the second chamber 20. The oil supply conduit 50 may have an arm portion 51 that extends through the internal housing of the supply arm 91 and is extended by a first bifurcation portion 53 and a second bifurcation portion 54. The two bifurcation portions 53, 54 may split from the arm portion 51 at a Y-shaped bifurcation 52 located outside the supply arm 91.The first bifurcation part 53 is fluidically connected to a supply port 11 of the first enclosure 10, and the second bifurcation part 54 is fluidly connected to a supply port 21 of the second enclosure 20.

[0055] The arm part 51 can be adapted to connect a first component of the lubrication system and the bifurcation 52, the first part of the bifurcation 53 can be adapted to connect the arm part 51 and the supply port 11 of the first enclosure 10, and the second part of the bifurcation 54 can be adapted to connect the arm part 51 and the supply port 21 of the second enclosure 20.

[0056] As illustrated by way of non-limiting example in [Fig.3] and [Fig.4], the lubrication system may further include a recovery service element corresponding to an oil recovery conduit 70 which extends through the internal housing of the recovery arm 92 and is fluidly connected to a recovery orifice 12 of the first enclosure 10 so as to allow oil to be evacuated outside the first enclosure 10.

[0057] The oil recovery conduit 70 can be substantially tubular in shape and have a first end opening into the first enclosure 10 at the recovery orifice 12, and a second end opening into a second component of the lubrication system.

[0058] The supply conduit 50, respectively the recovery conduit 70, can extend in a substantially radial direction for its part which is located in the cavity of the supply arm 91, respectively in the cavity of the recovery arm 92.

[0059] The first and / or second component of the lubrication system may include an oil reservoir, an auxiliary pump, a heat exchanger, an oil injector, etc. The oil reservoir may include cooling and / or filtering means for the oil contained in the reservoir. The injector is adapted to draw oil from the oil reservoir. The injector may be a jet, comprising an injection nozzle configured to inject the oil drawn from the injector.

[0060] The first and / or second element of the lubrication system is located in a radially external position relative to the outer ferrule 85 of the housing 83. The supply, or recovery, servient element must therefore pass through the supply arm 91, or recovery arm 92, of the housing 83 to cross the primary flow vein Vp, in order to connect the first, or second, element of the lubrication system to the first enclosure 10 and / or the second enclosure 20.

[0061] For example, the supply line 50 can be adapted to connect a first component in the form of an oil injector to the first chamber 10 and the second chamber 20. The oil injector is adapted to inject oil into the supply line 50, therefore into the first chamber 10 via the supply port 11 of the first chamber 10, and into the second chamber 20 via the supply port 21 of the second chamber 20. The recovery line 70 can be adapted to connect a second component in the form of an additional pump to the first chamber 10. The additional pump is adapted to pump the oil present in the first chamber 10, i.e., to draw the oil out of the first chamber 10, via the recovery port 12 and the recovery conduit 70. The work of the additional pump adds to the work of gravity to facilitate the evacuation of the oil from the first chamber 10.

[0062] The supply arm 91 may include a single internal housing for the passage of a single supply auxiliary element. The lubrication system then includes a single supply auxiliary element corresponding to an oil supply conduit 50 adapted to extend through the single internal housing of the supply arm 91 to connect a first component of the lubrication system with a supply port 11 of the first enclosure 10 and a supply port 21 of the second enclosure 20. Alternatively or in addition, the recovery arm 92 may include a single internal housing for the passage of a single recovery auxiliary element.The lubrication system then comprises a single recovery auxiliary element corresponding to an oil recovery conduit 70 adapted to extend through the single internal housing of the recovery arm 92 to connect a recovery port 12 of the first chamber 10 and a second component of the lubrication system. Such configurations with a single internal housing in the supply arm 91 and / or in the recovery arm 92 allow a single auxiliary element to pass through the supply arm 91 and / or the recovery arm 92 of the housing 83 to ensure the oil supply and / or oil recovery requirements of the two chambers 10, 20, namely the first chamber 10 and the second chamber 20.

[0063] The rotor can form a movable shaft extending substantially around the turbine axis L. The first enclosure 10 and / or the second enclosure 20 extend substantially around the rotor. The recovery arm 92 and the feed arm 91 can be opposed with respect to the rotor.

[0064] The lubrication system can be configured so that the oil can flow by gravity out of the first enclosure 10 and / or the second enclosure 20. In particular, the oil can flow from the supply port 11 of the first enclosure 10 to the recovery port 12 of the first enclosure 10. Thus, the oil falls by gravity from its injection at the supply port 11 of the first enclosure 10 to the recovery port 12 of the first enclosure 10. Alternatively or in addition, the oil is adapted to flow by gravity from the supply port 21 of the second enclosure 20 to the recovery port 61 of the second enclosure 20.

[0065] The lubrication system may further include: - a first pressurized air cavity 30 arranged around the first enclosure 10, and one or more sealing gaskets 31 arranged at the interface between the first enclosure 10 and the first cavity 30, so as to prevent oil from escaping from the first enclosure 10 into the first cavity 30; and / or - a second pressurized air cavity arranged around the second enclosure 20, and one or more sealing gaskets arranged at the interface between the second enclosure 20 and the second cavity, so as to prevent oil from escaping from the second enclosure 20 into the second cavity.

[0066] At least one seal 31 between the first chamber 10 and the first cavity 30, or between the second chamber 20 and the second cavity, can be cooled by the oil present in the first chamber 10 and the second chamber 20, respectively. The seal 31 is located between the two parts of the turbomachine 1, which have different rotational speeds, and is in contact with them, and is fixed to one of the two parts. The seal 31 therefore has a different rotational speed than the other of the two parts during the operation of the turbomachine 1. For example, in the case of a low-pressure turbine 8, the seal 31 can be located between a part of the rotor attached to the low-pressure shaft and a part attached to the fixed housing 83. The seal 31 can be, for example, a labyrinth seal or a segmented radial seal.

[0067] At least one sealing gasket 31 provides a seal between the first cavity 30, which contains pressurized air, and the first chamber 10, which contains air and oil, and between the second cavity and the second chamber 20, respectively. Thus, the sealing gasket 31 prevents oil from leaking from the first chamber 10 into the first cavity 30, and from the second chamber 20 into the second cavity, respectively. Since the first cavity 30 and the second cavity are pressurized, the pressure in the first cavity 30 and the second cavity is greater than the pressure in the first chamber 10 and the second chamber 20, respectively, which helps prevent oil leaks and thus contributes to the seal.

[0068] The first cavity 30 can be arranged in a radially external position relative to the first enclosure 10 and be adjacent to the first enclosure 10, a radially external wall of the first enclosure 10 forming a radially internal wall of the first cavity 30. An upstream seal 31 can be arranged upstream of the turbomachine shaft bearing 15 at the level of an upstream wall of the first enclosure 10, and / or a downstream seal 31 can be arranged downstream of the turbomachine shaft bearing 15 at the level of a downstream wall of the first enclosure 10.

[0069] The second cavity can be arranged in a radially external position relative to the second enclosure 20 and be adjacent to the second enclosure 20, a radially external wall of the second enclosure 20 forming a radially internal of the second cavity. An upstream seal can be disposed upstream of the electrical machine shaft bearing 22 at an upstream wall of the second enclosure 20, and / or a downstream seal can be disposed downstream of the electrical machine shaft bearing 22 at a downstream wall of the second enclosure 20.

[0070] The first enclosure 10 may include an annular piece provided with at least one oil circulation orifice 13, so as to allow oil to circulate in the first enclosure 10 through at least one oil circulation orifice 13.

[0071] At least one oil circulation orifice 13 of the first enclosure 10 allows the oil injected at the supply orifice 11 and the additional supply orifice 62 to circulate throughout the first enclosure 10.

[0072] In one embodiment, the lubrication system is implemented at the level of a turbine 7, 8 of the turbomachine 1. The turbine 7, 8 thus includes a lubrication system as described above.

[0073] The turbomachine shaft L is also the axis of rotation of the turbine rotor 7, 8 and corresponds to the longitudinal axis X of the lubrication system. The turbine may comprise several stages, each stage comprising a distributor 82 and a runner 81, as illustrated by way of non-limiting example in [Fig. 2]. The turbine rotor 7, 8 corresponds to the runner 81.

[0074] Each distributor 82 comprises a plurality of fixed blades, i.e. fixed to the stator or casing of the turbomachine, said fixed blades of the distributor 82 being circumferentially distributed around the axis of the turbomachine L. Each moving wheel 81 comprises a turbine disk 7, 8 and a plurality of blades circumferentially distributed around the axis of the turbomachine L.

[0075] For example, the lubrication system can be implemented at the level of a low pressure turbine 8 of the turbomachine 1.

[0076] Thus, the fixed housing 83 of the lubrication system corresponds to the exhaust housing (in English "TRF", for Turbine Rear Frame) of the low-pressure turbine 8, and the rotor of the lubrication system corresponds to the low-pressure turbine rotor 8, which includes a rotating wheel 81 of rotor blades integral with a rotor disc of the low-pressure turbine 8. The rotor 81 is adapted to be mounted to rotate with the low-pressure shaft of the turbomachine 1 around the turbomachine shaft L. For example, the rotor 81 can be attached and fixed to a low-pressure journal 101, the low-pressure journal 101 being assembled on the low-pressure shaft of the turbomachine 1, for example by means of splines, in order to drive the low-pressure shaft in rotation.

[0077] The inner hub 84 and the outer ferrule 85 of the lubrication system correspond respectively to the inner hub and the outer ferrule of the exhaust housing 83 of the low-pressure turbine 8, which are adapted to delimit together the part of the primary flow vein Vp which extends at the level of the low pressure turbine 8.

[0078] The turbomachine shaft bearing 15 is mounted between the low-pressure journal 101, which is rotationally fixed to the low-pressure shaft, and the exhaust housing 83, and guides the rotation of the rotor relative to the exhaust housing 83. The inner race 151 of the turbomachine shaft bearing 15 is rotationally fixed to the low-pressure journal 101, and the outer race 152 of the turbomachine shaft bearing 15 is rotationally fixed to the exhaust housing 83. The turbomachine shaft bearing 15 is located in the first enclosure 10. The first enclosure 10 surrounds the low-pressure shaft at the level of the low-pressure turbine 8.

[0079] The internal hub 84 of the exhaust housing 83 may include a frustoconical portion 96 forming a support for the turbomachine shaft bearing 15. The turbomachine shaft bearing 15 is then disposed between the trunnion of the low-pressure shaft and a longitudinal extension 97 of the frustoconical portion 96 of the exhaust housing 83. At least one oil circulation orifice 13 of the first enclosure 10 may be formed in the frustoconical portion 96 of the internal hub 84 of the exhaust housing 83.

[0080] The second enclosure 20 can also surround the low-pressure shaft at the low-pressure turbine 8. The electric machine 22 can be substantially annular and extend around the low-pressure shaft. The second enclosure 20 can be located downstream of the first enclosure 10, for example, directly downstream of the first enclosure 10.

[0081] The first cavity 30 and / or the second cavity is a pressurized air chamber, which means that the first cavity 30 and / or the second cavity is maintained at a pressure higher than the pressure prevailing in the stages of the low-pressure turbine 8. The sealing gasket 31 disposed between the first chamber 10 and the cavity 30 is integral with the exhaust housing 83, and is disposed in contact with a track integral in rotation with the low-pressure shaft of the turbomachine 1.

[0082] The low-pressure turbine 8 may further include a clevis for fixing the exhaust housing 83 to the turbomachine 1, the clevis being located on the outer ferrule 85 of the exhaust housing 83.

[0083] Alternatively, the lubrication system can be implemented at the level of a high-pressure turbine 7 of the turbomachine 1. The rotor of the lubrication system then corresponds to the rotor of the high-pressure turbine 7, which includes a moving wheel of rotor blades fixed to a rotor disc of the high-pressure turbine 7. The rotor of the high-pressure turbine 7 is rotationally fixed to the high-pressure shaft, for example by being attached and fixed to a high-pressure trunnion assembled on the high-pressure shaft.

[0084] The turbomachine shaft bearing is mounted between the high-pressure journal, which is rotationally fixed to the high-pressure shaft, and the fixed housing, so as to guide the rotation of the rotor relative to the fixed housing of the high-pressure turbine 7. The turbomachine shaft bearing is located in the first lubrication chamber 10. The first chamber 10 surrounds the high-pressure shaft at the level of the high-pressure turbine 7.

[0085] The second enclosure 20 can also surround the high-pressure shaft at the high-pressure turbine 7. The electric machine 22 can be substantially annular and extend around the high-pressure shaft. The second enclosure 20 can be located downstream of the first enclosure 10, for example, directly downstream of the first enclosure 10.

[0086] In another embodiment, the lubrication system is implemented at the level of a compressor, for example a low-pressure compressor 4 or a high-pressure compressor 5, of the turbomachine 1. The fixed housing can be an intermediate housing, and the rotor can be the low-pressure shaft in the case of a low-pressure compressor 4, or the high-pressure shaft in the case of a high-pressure compressor 5.

[0087] The turbomachine 1 may include a lubrication system as described above. In particular, the turbomachine 1 may include a turbine 7, 8 comprising a lubrication system as described above.

[0088] An aircraft may include at least one turbomachine 1 as described above, in particular including at least one lubrication system as described above.

[0089] The solution described above is not limited to the embodiment examples described, and can be used in other locations of the turbomachine 1 comprising a rotor and a fixed casing 83, the rotor being mounted movable in rotation relative to the fixed casing 83 around the turbomachine axis L.

[0090] Other embodiments can be envisaged and a person skilled in the art can easily modify the embodiments or examples set out above or consider others while remaining within the scope of the invention.

Claims

Demands

1. Lubrication system for a turbomachine (1), said lubrication system extending about a longitudinal axis (X) and comprising: - a first oil lubrication chamber (10) extending about the longitudinal axis (X); - a second oil lubrication chamber (20) extending about the longitudinal axis (X); - a connecting channel (60) adapted to fluidly connect the first chamber (10) and the second chamber (20); - a turbomachine shaft bearing (15) extending about the longitudinal axis (X) and arranged to be lubricated in the first chamber (10); - an electrical machine shaft bearing (22) arranged to be lubricated in the second chamber (20); and - a pump (23) configured to extract oil from the second enclosure (20) to send it into the first enclosure (10) through the connecting channel (60).

2. Lubrication system according to claim 1, wherein the pump (23) is housed in the second enclosure (20) and is supplied with electrical energy by the electric machine (22).

3. Lubrication system according to claim 1 or 2, further comprising: - a fixed housing (83) comprising an inner hub (84), an outer ferrule (85) extending around the inner hub (84), a supply arm (91) connecting the inner hub (84) to the outer ferrule (85), and a recovery arm (92) connecting the inner hub (84) to the outer ferrule (85), in which the supply arm (91) comprises an internal housing for the passage of a supply service element and / or in which the recovery arm (92) comprises an internal housing for the passage of a recovery service element; and - a rotor mounted movable in rotation relative to the housing (83) about the longitudinal axis (X), the turbomachine shaft bearing (15) being configured to guide the rotor in rotation relative to the housing (83).

4. Lubrication system according to claim 3, comprising a supply auxiliary element corresponding to an oil supply conduit (50) extending through the internal housing of the supply arm (91) to supply oil to the first chamber (10) and the second chamber (20), wherein the supply conduit in oil (50) has an arm portion (51) which extends through the internal housing of the feed arm (91) and which is extended by a first bifurcation portion (53) and a second bifurcation portion (54), the first bifurcation portion (53) being fluidly connected to a feed port (11) of the first enclosure (10), and the second bifurcation portion (54) being fluidly connected to a feed port (21) of the second enclosure (20).

5. Lubrication system according to claim 3 or 4, further comprising a recovery servicing element corresponding to an oil recovery conduit (70) which extends through the internal housing of the recovery arm (92) and is fluidly connected to a recovery orifice (12) of the first enclosure (10) so as to allow oil to be evacuated outside the first enclosure (10).

6. Lubrication system according to any one of the preceding claims, configured so that the oil can flow by gravity out of the first enclosure (10) and / or the second enclosure (20).

7. A lubrication system according to any one of the preceding claims, further comprising: - a first pressurized air cavity (30) disposed around the first enclosure (10), and one or more sealing gaskets (31) disposed at the interface between the first enclosure (10) and the first cavity (30), so as to prevent oil from escaping from the first enclosure (10) into the first cavity (30); and / or - a second pressurized air cavity disposed around the second enclosure (20), and one or more sealing gaskets disposed at the interface between the second enclosure (20) and the second cavity, so as to prevent oil from escaping from the second enclosure (20) into the second cavity.

8. Lubrication system according to any one of the preceding claims, wherein the first enclosure (10) comprises an annular piece having at least one oil circulation orifice (13), so as to permit oil to circulate in the first enclosure (10) through at least one oil circulation orifice (13).

9. Low pressure turbine (8) for a turbomachine (1) comprising a lubrication system according to any one of the preceding claims.

10. Turbomachine (1) comprising a low pressure turbine (8) according to claim 9. 19

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