Lubrication system for the housings of a turbomachine

Abstract

Lubrication system (60) comprising: - several chambers (63A, 63B, 63C, 63D), each designed to house at least one component of a turbomachine to be lubricated, - a lubricant reservoir (62), - a pump (64) configured to pump lubricant from the reservoir (62), - a distributor (66) configurable in a primary configuration if the turbomachine speed exceeds a reference speed and in an auxiliary configuration otherwise, the distributor (66) being configured in the auxiliary configuration to transfer lubricant from the pump (64) to the chambers (63A, 63B, 63C, 63D) and to the reservoir (62) according to constant auxiliary distribution proportions, the distributor (66) being configured in the primary configuration to transfer lubricant from the pump (64) only to the chambers (63A, 63B, 63C, 63D) according to primary distribution proportions constants. Figure to be published for the abstract: Figure 5

Description

Title of the invention: Lubrication system for the housings of a turbomachine DOMAIN

[0001] The invention relates to a lubrication system for the housings of a turbomachine, in particular a turbomachine with at least two operating modes, the lubricant distribution requirement between the housings varying significantly from one mode to the other. In what follows, the term "operating mode," or simply "mode," refers to the rotational speed of the turbomachine, in other words, the rotational speed of a drive shaft of the turbomachine. STATE OF THE ART

[0002] In a turbomachine, the lubricant supply serves to lubricate, but also and especially to cool, components such as bearings, bushings, and gears. These various components are distributed within different enclosures, including one (or more) engine enclosure(s) and possibly an accessory gearbox enclosure (also known as an accessory gearbox, abbreviated as AGB), or even a reduction gearbox enclosure containing a speed reduction mechanism (also known as a reduction gearbox, abbreviated as RGB). The lubrication system is configured to distribute the lubricant flow among the different enclosures. In a conventional turbomachine, this distribution of the lubricant is constant and does not vary according to the turbomachine's operating speed.

[0003] In some cases, the required lubricant distribution for the satisfactory lubrication and cooling of the lubricated parts of the enclosures varies significantly depending on the operating conditions. A constant distribution of the lubricant in these cases results in an oversupply of lubricant to at least one of the enclosures at at least one operating condition. The enclosure(s) concerned may then be "flooded" by the lubricant. This can lead to lubricant churning and a significant increase in lubricant temperature. Solid particles, such as coke, may be generated, which can subsequently damage the lubricated parts.

[0004] There is therefore a need for a turbomachine enclosure lubrication system that better accounts for the distribution of the required lubricant flow rate between enclosures, which varies according to the turbomachine's operating speed. PRESENTATION OF DRAWINGS

[0005] Other features and advantages will become apparent from the following description, which is purely illustrative and not exhaustive, and should be read in conjunction with the accompanying figures, among which:

[0006] - Figure 1 schematically represents an aircraft comprising systems propulsive,

[0007] - [Fig. 2] schematically represents, in partial view and in section, a example of a propulsion system

[0008] - Figure 3 schematically represents a first example of a mechanism planetary reduction,

[0009] - Figure 4 schematically represents a first example of a mechanism epicycloidal reduction

[0010] - Figure 5 schematically represents a lubrication system for a turbomachine,

[0011] - Figure 6 schematically represents a lubrication method for a turbomachine, and

[0012] - Figure 7 schematically represents a method for dimensioning a lubrication system of a turbomachine. EXPOSED

[0013] One aim of the present presentation is to propose a more satisfactory turbomachine enclosure lubrication system than in the prior art.

[0014] The objective is achieved through a turbomachine lubrication system, the system comprising:

[0015] - several enclosures, each designed to house at least one part of the turbomachine to lubricate,

[0016] - a lubricant reservoir,

[0017] - a pump configured to pump lubricant contained in the reservoir,

[0018] - a configurable distributor in a main configuration if a regime of the turbomachine is beyond a reference regime and in an auxiliary configuration otherwise, the distributor being configured in the auxiliary configuration to transmit lubricant from the pump to the enclosures and to the reservoir in constant auxiliary distribution proportions, the distributor being configured in the main configuration to transmit lubricant from the pump to only the enclosures in constant main distribution proportions.

[0019] Such a system is advantageously and optionally complemented by the following various features, taken alone or in combination: - a ratio of an auxiliary distribution proportion associated with the first speaker to an auxiliary distribution proportion associated with the second speaker is different from a ratio of a proportion of main distribution associated with the first of the speakers on a proportion of main distribution associated with the second of the speakers;

[0020] - the distributor comprises a main set of valves in which each valve is fluidly connected to one of the chambers, an auxiliary set of valves in which one of the valves is fluidly connected to the reservoir and each of the other valves is fluidly connected to one of the chambers, and a distributor configured to transmit, depending on the turbomachine speed, lubricant from the pump to the main set or to the auxiliary set;

[0021] - the distributor includes a drawer mounted movable in a direction between a main position and an auxiliary position, the distributor being configured to transmit lubricant from the pump to the main set if the spool is in the main position and to the auxiliary set if the spool is in the auxiliary position, and an actuator configured to move the spool according to the speed;

[0022] -1'actuator includes a transmitter configured to exert on the drawer a constraint along the direction oriented towards one of the main and auxiliary positions, a constraint value depending on the operating regime, and a return element configured to exert a return force on the spool oriented towards the other of the main and auxiliary positions; and

[0023] - the system is configured to circulate a flow of lubricant from the pump to the distributor and a fraction of the flow from the distributor to only a portion of the enclosures, the system comprising a common exchanger configured to cool the flow, and a particular exchanger configured to cool the fraction of the flow.

[0024] The presentation also relates to a turbomachine comprising a lubrication system such as has been presented above.

[0025] Such a turbomachine is advantageously and optionally complemented by a blower, a drive shaft and a speed reduction mechanism configured to be driven in rotation by the drive shaft and to drive in rotation the blower, the enclosures of the lubrication system including an enclosure housing the speed reduction mechanism.

[0026] The presentation also relates to an aircraft comprising a turbomachine such as has been presented above.

[0027] The presentation also relates to a method for dimensioning a lubrication system for a turbomachine previously presented in its version completed by a fan, a drive shaft and a speed reduction mechanism. This method comprises the following steps:

[0028] - (El) identification of the reference regime, of a first regime beyond the regime of reference and a second regime below the reference regime,

[0029] - (E2) for the enclosure housing the speed reduction mechanism, identification of a first required lubricant flow rate (Qld) for the first regime and a second required lubricant flow rate (Qlc) for the second regime, and for the other enclosures (identification of a third required lubricant flow rate (Q2d) for the first regime and a fourth required lubricant flow rate (Q2c) for the second regime, - (E3) determination of a pump configured to deliver in the first operating at a rate where the lubricant flow is greater than or equal to the main flow rate (Qld+Q2d), which is equal to the sum of the first and third flow rates. - (E6) determination of a principal distribution proportion associated with the reduction mechanism corresponding to the ratio of the first flow rate (Qld) to the main flow rate (Qld+Q2d) and a main distribution proportion associated with the other enclosures corresponding to the ratio of the third flow rate (Q2d) to the main flow rate (Qld+Q2d), - (E7) determination of an auxiliary flow rate (Qc) extracted from the reservoir by the pump in the second regime, - (E8) determination of an auxiliary flow rate to the corresponding reservoir (Qr) to a difference between the auxiliary flow rate (Qc) and the sum of the second flow rate (Qlc) and the fourth flow rate (Q2c), and - (E9) determination of an auxiliary distribution proportion associated with the reservoir corresponding to the ratio of the auxiliary flow to the reservoir (Qr) on the auxiliary flow (Qc), of an auxiliary distribution proportion associated with the reduction mechanism corresponding to the ratio of the second flow (Qlc) on the auxiliary flow (Qc) and of an auxiliary distribution proportion associated with the other enclosures corresponding to the ratio of the fourth flow (Q2c) on the auxiliary flow (Qc).

[0030] The presentation finally relates to a method for lubricating a turbomachine, the method comprising: - a step involving pumping lubricant contained in a turbomachine reservoir, and - a lubrication stage for turbomachine parts, the parts being housed in several turbomachine chambers, lubrication being carried out according to a primary configuration if the turbomachine speed is above a reference speed and according to an auxiliary configuration otherwise, the pumped lubricant being transmitted in the auxiliary configuration to the two chambers and to the reservoir according to constant auxiliary distribution proportions, the pumped lubricant being transmitted in the main configuration towards only the two speakers and according to constant main distribution proportions. DETAILED DESCRIPTION OF AN EMBODIMENT MODEL Turbomachine

[0031] In the example illustrated in [Fig. 1], the aircraft is an airplane 100 comprising a fuselage 101 and two wings 102. In this example, the aircraft comprises two propulsion systems 1, each propulsion system 1 being attached to a respective wing 102 of the airplane 100 by means of a pylon. In another embodiment, the aircraft could comprise one or more propulsion system(s) attached to the fuselage 101.

[0032] Fig. 2 schematically represents, in partial view and in section, an example of a propulsion system 1.

[0033] In this example, the propulsion system 1 is a twin-shaft gas turbine engine with a shrouded fan. It should be noted that the present description is not limited to this example of an engine and also applies to single-shaft propulsion systems and / or those without a speed reduction mechanism. The invention further applies to electric or hybrid motors.

[0034] In [Fig.2], the propulsion system 1 has a main direction extending along a longitudinal axis X. The propulsion system 1 comprises a blower section 2 and a primary body 3, often called a "gas generator".

[0035] The blower section 2 comprises a blower 22 and a blower housing 12. The blower 22 comprises a blower rotor 9. The blower housing 12 surrounds the blower rotor 9. The blower rotor 9 is rotatably mounted relative to the blower housing 12.

[0036] The fan rotor 9 comprises a fan hub 13 and fan blades 14 extending radially from the hub 13. The fan blades 14 may be fixed relative to the fan hub 13 or have variable pitch. In the latter case, each of the fan blades 14 is pivotally mounted relative to the fan hub 13 about a pitch axis and is connected to a pitch-changing mechanism (not shown) mounted in the propulsion system 1. The pitch-changing mechanism allows the pitch angle of the fan blades 14 to be adjusted according to the flight phases.

[0037] Furthermore, in this example, the blower section 2 also includes a blower stator 16 fixedly mounted on the blower housing 12. The blower stator 16 includes fixed vanes 17 generally referred to as "outlet vanes" (or "OGV," for "Outlet Guide Vane"). This set of fixed vanes serves to straighten and regulate the airflow downstream of the blower rotor 9 to contribute to engine thrust. This set of fixed blades can also play a role in noise reduction.

[0038] Alternatively, the outlet blades 17 could have a variable pitch. If so, and similarly to the fan blades 14 of the fan rotor 9, the base of the outlet blades 17 is pivotally mounted about a pitch axis and is connected to a pitch-changing mechanism (not shown), the pitch being adjusted according to the flight phases by the pitch-changing mechanism.

[0039] The primary body 3 comprises a compressor section 29, a combustion chamber 6 and a turbine section 30.

[0040] The compressor section 29 includes a low pressure compressor 4 and a high pressure compressor 5.

[0041] The low-pressure compressor 4 comprises a rotor 41 suitable for being driven in rotation relative to the housing 31 of the propulsion system 1 and a stator 42 fixedly mounted on the housing 31.

[0042] The rotor 41 of the low-pressure compressor 4 comprises movable wheels 4a and the stator 42 of the low-pressure compressor 4 comprises fixed wheels 4b. The movable wheels 4a are arranged alternately with the fixed wheels 4b, thus forming a succession of low-pressure compressor stages.

[0043] Similarly, the high-pressure compressor 5 includes a rotor 51 suitable for being driven in rotation relative to the housing 31 of the propulsion system 1 and a stator 52 fixedly mounted on the housing 31.

[0044] The rotor 51 of the high-pressure compressor 5 includes movable wheels 5a and the stator 52 of the high-pressure compressor 5 includes fixed wheels 5b. The movable wheels 5a are arranged alternately with the fixed wheels 5b, thus forming a succession of high-pressure compressor stages.

[0045] The turbine section 30 comprises a high-pressure turbine 7 and a low-pressure turbine 8.

[0046] The high-pressure turbine 7 comprises a rotor 71 suitable for being driven in rotation relative to the housing 31 of the propulsion system 1 and a stator 72 fixedly mounted on the housing 31.

[0047] The rotor 71 of the high-pressure turbine 7 comprises rotating wheels 7a and the stator 72 of the high-pressure turbine 7 comprises fixed wheels 7b. The rotating wheels 7a are arranged alternately with the fixed wheels 7b, thus forming a succession of high-pressure turbine stages.

[0048] Similarly, the low-pressure turbine 8 comprises a rotor 81 suitable for being driven in rotation relative to the casing 31 of the propulsion system 1 and a stator 82 fixedly mounted on the casing 31.

[0049] The rotor 51 of the high-pressure compressor 5 includes movable wheels 5a and the stator 52 of the high-pressure compressor 5 includes fixed wheels 5b. The movable wheels 5a are arranged alternately with the fixed wheels 5b, thus forming a succession of high-pressure compressor stages.

[0050] The turbine section 30 comprises a high-pressure turbine 7 and a low-pressure turbine 8.

[0051] The high-pressure turbine 7 comprises a rotor 71 suitable for being driven in rotation relative to the housing 31 of the propulsion system 1 and a stator 72 fixedly mounted on the housing 31.

[0052] The rotor 71 of the high-pressure turbine 7 comprises rotating wheels 7a and the stator 72 of the high-pressure turbine 7 comprises fixed wheels 7b. The rotating wheels 7a are arranged alternately with the fixed wheels 7b, thus forming a succession of high-pressure turbine stages.

[0053] Similarly, the low-pressure turbine 8 comprises a rotor 81 suitable for being driven in rotation relative to the housing 31 of the propulsion system 1 and a stator 82 fixedly mounted on the housing 31.

[0054] The rotor 81 of the low-pressure turbine 8 comprises rotating wheels 8a and the stator 82 of the low-pressure turbine 8 comprises fixed wheels 8b. The rotating wheels 8a are arranged alternately with the fixed wheels 8b, thus forming a succession of low-pressure turbine stages.

[0055] The propulsion system 1 includes a low-pressure shaft 11 connecting the rotor 41 of the low-pressure turbine 4 to the rotor 81 of the low-pressure compressor 8, the low-pressure shaft 11 being mounted rotatably relative to the housing 31 around the longitudinal axis X.

[0056] When the propulsion system 1 is in operation, the rotor 81 of the low-pressure turbine 8 drives the rotor 41 of the low-pressure compressor 4 through the low-pressure shaft 11.

[0057] The propulsion system 1 further comprises a blower shaft 20 and a reduction mechanism 19. The blower rotor 9 is fixedly mounted on the blower shaft 20. The reduction mechanism 19 has an inlet and an outlet. The inlet of the reduction mechanism 19 is connected to the low-pressure shaft 11, and the outlet of the reduction mechanism 19 is connected to the blower shaft 20. Thus, when the propulsion system 1 is in operation, the rotor 81 of the low-pressure turbine 8 drives not only the rotor 41 of the low-pressure compressor 4, but also the blower rotor 9, via the low-pressure shaft 11, the reduction mechanism 19, and the blower shaft 20.

[0058] Thanks to the reduction mechanism 19, the blower rotor 9 is driven into rotation at a speed lower than the rotational speed of the rotor 41 of the low pressure turbine 4.

[0059] The reduction mechanism 19 thus makes it possible to independently control the rotation speed of the blower 22 and the rotation speed of the low-pressure turbine 8 and the low-pressure compressor 4.

[0060] The low-pressure turbine 8, the low-pressure shaft 11, the low-pressure compressor 4, the blower shaft 20, the reduction mechanism 19 and the blower 22 together form the "low-pressure body" of the propulsion system 1.

[0061] The propulsion system 1 further comprises a high-pressure shaft 10 connecting the rotor 51 of the high-pressure turbine 5 to the rotor 71 of the high-pressure compressor 7, the high-pressure shaft 10 being rotatably mounted relative to the housing 31 about the longitudinal axis X. The high-pressure shaft 10 is coaxial with the low-pressure shaft 11 and extends around the low-pressure shaft 11

[0062] When the propulsion system 1 is in operation, the rotor 81 of the low-pressure turbine 8 drives the rotor 51 of the low-pressure compressor 5 through the low-pressure shaft IL

[0063] The high-pressure turbine 7, the high-pressure shaft 10 and the high-pressure compressor 4 together form the "high-pressure body" of the propulsion system 1.

[0064] The low-pressure shaft 11 and the high-pressure shaft 10 can be co-rotating, that is, driven in the same direction of rotation around the longitudinal axis X. Alternatively, the low-pressure shaft 11 and the high-pressure shaft 10 can be contra-rotating, that is, driven in opposite directions of rotation around the longitudinal axis X.

[0065] The double-body propulsion system 1 may in particular include a single-stage high-pressure turbine 7, i.e. comprising exactly one stage, or a two-stage high-pressure turbine 7, i.e. comprising exactly two stages (as illustrated in the example of [Fig.2]).

[0066] When the propulsion system is in operation, an airflow F entering the propulsion system 1 passes through the blower 22 and is then divided between a primary airflow Fl and a secondary airflow F2, which flow upstream to downstream in the propulsion system 1.

[0067] The secondary airflow F2, also called the "bypass airflow", flows in the secondary vein, around the primary body 3. The secondary airflow F2 cools the periphery of the primary body 3 and is used to generate most of the thrust provided by the propulsion system 1.

[0068] The primary airflow Fl flows in a primary channel 29 inside the primary body 3, passing successively through the compressor section 29 (low-pressure compressor 4 and high-pressure compressor 5), the combustion chamber 6 where it is mixed with fuel to serve as an oxidizer, and the turbine section 30 (high-pressure turbine 7 and low-pressure turbine 8). The passage The primary airflow Fl through the turbine section 30 receiving energy from the combustion chamber 6 causes a rotation of the moving wheels 7a, 8a of the turbine section 30, which in turn drive the moving wheels 4a, 5a of the compressor section 29 and the blower rotor 9 into rotation.

[0069] The reduction mechanism 19 may include an epicycloidal or planetary reduction mechanism, single-stage or two-stage.

[0070] For example, [Fig. 3] illustrates a planetary (or "star") type reduction mechanism 19. The reduction mechanism 19 comprises a sun pinion 19a (input of the reduction mechanism 19), centered on an axis of rotation of the reduction mechanism 19 generally coincident with the longitudinal axis X and configured to be driven in rotation by the low-pressure shaft 11, a ring gear 19b (output of the reduction mechanism 19) coaxial with the sun pinion 19a and configured to drive the blower shaft 20 in rotation about its axis X of rotation, and a series of satellites 19c distributed circumferentially around the axis X of rotation of the rotor 9 of the blower section 2, between the sun pinion 19a and the ring gear 19b, each satellite gear 19c being internally meshed with the sun pinion 19a and externally with the ring gear 19b.The series of satellites 19c is mounted on a satellite carrier 19d which is fixed relative to a stator part 19e of the propulsion system 1, for example relative to a housing of the compressor section 4, 5.

[0071] In another example, [Fig.4] illustrates an epicycloidal (or "planetary" in English) type reduction mechanism 19, in which case the ring 19b is fixedly mounted on the stator part 19e of the propulsion system 1 and the blower shaft 20 is driven in rotation by the planet carrier 19d.

[0072] Regardless of the configuration of the reduction mechanism 19, the diameter of the ring gear 19b and the satellite carrier 19d are greater than the diameter of the solar pinion 19a, so that the rotational speed of the rotor 9 of the blower section 2 is less than the rotational speed of the low pressure shaft 11. Turbomachine lubrication system

[0073] With reference to [Fig. 5], a lubrication system 60 of the propulsion system includes a reservoir 62. The reservoir 62 is configured to contain the lubricant necessary for the lubrication and cooling of components such as bearings, bushings, or gears of the propulsion system. The reservoir is configured to contain all the lubricant necessary to lubricate and cool the turbomachine.

[0074] The various parts of the turbomachine to be cooled are distributed in enclosures 63 of the lubrication system.

[0075] The lubrication system includes enclosures 63, each designed to house a part of the turbomachine to be lubricated. The reservoir 62, however, does not contain any part of the turbomachine to be lubricated.

[0076] The enclosures 63 are lubrication chambers intended to be installed in the turbomachine. The enclosures 63 comprise a lubricant inlet and a lubricant outlet. The enclosures 63 are configured to receive a flow of lubricant through the lubricant inlet and allow it to flow to the lubricant outlet. The enclosures 63 are sealed in the sense that the mass flow rate of lubricant is maintained between their inlet and outlet. In particular, the lubricant does not flow out of the enclosure into an adjacent enclosure. The sealing of the enclosures can be ensured, in particular, by means of gaskets.

[0077] The lubrication system comprises at least two enclosures 63. For example, the enclosures 63 may include a reduction gear enclosure 63A in which the reduction mechanism 19 is located when it is present in the propulsion system. The enclosures 63 may include motor enclosures 63B and 63C, each motor enclosure housing some of the bearings and bushings ensuring the proper operation of the blower on the motor shaft or shafts. The enclosures 63 may further include an accessory box enclosure 63D in which the accessory box is located.

[0078] The lubrication system 60 includes a pump 64 configured to extract lubricant from the reservoir and transfer it to the enclosures 63. The pump 64 is thus fluidly connected to the reservoir. The pump 64 can produce a flow of lubricant from the reservoir. The lubricant flow exiting the pump 64 can then be transferred to various sub-parts of the lubrication system 60, such as the enclosures 63.

[0079] The lubrication system 60 includes a distributor 66. The distributor 66 is fluidically connected to an outlet of the pump 64, either directly or indirectly via, for example, a filter. The distributor 66 is configured to distribute the flow of lubricant pumped by the pump 64 to different sub-parts of the lubrication system 60, such as the enclosures 63. It should be noted that the distributor 66 is configured to distribute the entire flow of lubricant pumped by the pump 64.

[0080] The distributor 66 is configurable in a main configuration if a turbomachine regime is beyond a reference regime and in an auxiliary configuration otherwise.

[0081] The operating speed of the turbomachine corresponds, for example, to the rotational speed of a drive shaft of the turbomachine, for example the high-pressure shaft when one exists. A reference operating speed is, for example, a predetermined rotational speed.

[0082] For example, the distributor 66 is in the main configuration if the rotational speed is greater than the reference speed, and the distributor 66 is in the auxiliary configuration if the rotational speed is less than or equal to the reference speed. The reference speed may, in particular, be a rotational speed The reference engine speed is lower than the shaft speed when the aircraft is in takeoff or cruise and greater than or equal to the shaft speed when the aircraft is at engine idle. The reference engine speed is chosen to separate a first engine speed above the reference speed, for example, the engine speed reached when the aircraft is in takeoff or cruise, and a second engine speed below the reference speed, for example, the engine speed reached when the aircraft is at engine idle.

[0083] The distributor is configured in the main configuration to transfer lubricant from the pump 64 to the chambers 63. In other words, the distributor transfers the entire lubricant flow from the pump 64 to the chambers and only to the chambers. This transfer of lubricant to the chambers 63 occurs according to constant main distribution proportions. Each chamber is associated with a main distribution proportion. For example, if the lubrication system comprises two cavities, a first main distribution proportion can be associated with one of the two chambers and a second main distribution proportion with the second chamber. The first proportion corresponds to the ratio of the lubricant flow entering the first cavity to the total lubricant flow from the pump 64.The second first proportion corresponds to the ratio of the lubricant flow entering the second cavity to the total lubricant flow from pump 64. The sum of the first main distribution proportion and the second main distribution proportion is equal to 1 or 100%.

[0084] The fact that the main distribution proportions are constant means that they do not depend on the turbomachine's operating conditions. The transmission of lubricant to the cavities 63 occurs according to constant main distribution proportions as long as the distributor 66 is in the main configuration.

[0085] The distributor is configured in the auxiliary configuration to transfer lubricant from the pump 64 to the chambers 63 and to the reservoir 62. In other words, the distributor 66 separates the entire lubricant flow from the pump 64 into a portion that is transferred to the chambers only and another portion that is transferred to the reservoir 62. The transfer of lubricant from the distributor 66 to the reservoir 62 is understood here as direct, that is, the lubricant flow passes from the distributor 66 to the reservoir 62 only through a conduit. In particular, the transfer of lubricant from the distributor 66 to the reservoir 62 does not pass through any of the cavities 63. As before, an auxiliary distribution proportion is associated with each cavity and an auxiliary distribution proportion is associated with each reservoir.For example, in the case where the lubrication system includes two cavities, a first auxiliary distribution proportion can be associated with the . The first of the two chambers and a second auxiliary main distribution proportion to the second of the two chambers. The first proportion corresponds to the ratio of the lubricant flow entering the first chamber to the total lubricant flow from pump 64. The second proportion corresponds to the ratio of the lubricant flow entering the second chamber to the total lubricant flow from pump 64. The sum of the first auxiliary distribution proportion, the second auxiliary distribution proportion, and the auxiliary distribution proportion associated with the reservoir is equal to 1 or 100%.

[0086] The fact that the auxiliary distribution proportions are constant means that they do not depend on the turbomachine's operating conditions. The transmission of lubricant to the cavities 63 and the reservoir occurs according to constant auxiliary distribution proportions as long as the distributor 66 is in the auxiliary configuration.

[0087] The distributor allows for two operating modes of the lubrication system. In the primary mode, all the pumped lubricant is distributed between the chambers. This mode corresponds to a relatively higher turbomachine speed and generally to relatively greater cooling requirements. This primary mode is activated, for example, when the aircraft is in takeoff or cruise phase. In the secondary mode, only a portion of the pumped lubricant is distributed between the chambers, the remainder being returned to the reservoir. The modes are activated according to the turbomachine speed. This mode corresponds to a relatively lower turbomachine speed and generally to relatively lower cooling requirements. This secondary mode is activated, for example, when the aircraft is in engine idle phase.This allows for a variable distribution of the lubricant flow at the pump outlet, depending on the turbomachine's operating speed. In the auxiliary configuration, this notably reduces the proportion of lubricant flow supplying the chambers 63. This limits the risk of over-supplying the chambers 63.

[0088] It should be noted that imposing constant primary distribution proportions and constant auxiliary distribution proportions gives the distributor a binary character. This allows the use of a distributor that is simpler, cheaper, and more robust. If the auxiliary or primary distribution proportions depended on the operating conditions, the distributor would be of a more complex design requiring more elaborate and potentially more fragile parts, ultimately resulting in higher costs and potentially reduced reliability.

[0089] It can also be foreseen that a ratio of an auxiliary distribution proportion associated with the first speaker to an auxiliary distribution proportion associated with the second speaker is different from a ratio of a main distribution proportion associated with the first speaker to a proportion of The main distribution is associated with the second chamber. In this case, the lubricant flow distribution between the chambers varies according to the turbomachine's operating speed. This allows for even finer adjustment of the flows transmitted to each chamber, further limiting the risk of lubricant oversupply within the chambers.

[0090] To implement the switch from the main configuration to the auxiliary configuration, the lubrication system may include a sensor configured to measure the turbomachine speed, with the distributor 66 being configured in the auxiliary configuration if the measurement result is less than or equal to a predetermined threshold. Such a sensor may, in particular, be a magnetic or optical sensor positioned opposite a drive shaft of the turbomachine. The signal produced by the sensor can then be used to control the distributor so as to place the distributor in the main or auxiliary configuration.

[0091] In the case where the pump 64 is driven by a turbomachine shaft, the pumped lubricant pressure reflects the turbomachine's rotational speed. In other words, the lubricant pressure changes with the rotational speed of the turbomachine shaft driving the pump 64, according to a predetermined relationship that can be refined based on parameters such as the measured lubricant temperature. It is then possible to use the constrained pressure to construct a distributor control.

[0092] In relation to [Fig.5], the distributor 66 may include two sets of lubricant flow distribution valves.

[0093] A distribution valve is a device that receives an incoming flow of fluid, such as a lubricant flow, and is configured to deliver a fraction of the incoming flow at the outlet. The fraction of the flow is controllable.

[0094] A distribution valve set is a set of at least two valves arranged in parallel. In other words, the valve inlets are fluidically connected at the inlet of the valve set. An incident flow of lubricant can be sent to the inlet of the valve set. Each valve can be adjusted to allow more or less lubricant to pass to the outlet. It is thus possible to control the distribution of the incident flow at the outlet of the different valves.

[0095] The distributor 66 may include a first set of valves, referred to as the main set 67, in which each valve is fluidly connected to one of the chambers 63. In other words, the valve inlets are fluidly connected to each other at the inlet of the valve set, and each valve outlet is fluidly connected to a chamber inlet. Conversely, each chamber inlet is fluidly connected to one and only one valve outlet. The main distribution valves are set to distribute the lubricant flow according to the main distribution proportions. With reference to [Fig. 5], The lubrication system comprises four chambers 63A, 63B, 63C, and 63D, and the main set 67 comprises the main distribution valves 73 and 74. The main distribution valve 73 is fluidly connected to chambers 63B, 63C, and 63D. The main distribution valve 74 is fluidly connected to chamber 63A.

[0096] The distributor 66 may include a second set of valves, referred to as the auxiliary set 68. in which one of the valves is fluidly connected to the reservoir 62 and each of the other valves is fluidly connected to one of the chambers 63. In other words, the valve inlets are fluidly connected to each other at the inlet of the valve set, and each valve outlet is fluidly connected either to the reservoir or to a chamber inlet. Conversely, the reservoir is connected to one and only one of the valve outlets, and each chamber inlet is fluidly connected to one and only one valve outlet. The auxiliary distribution valves are set to distribute the lubricant flow according to the auxiliary distribution proportions. With reference to [Fig. 5], the main set 68 comprises the main distribution valves 75, 76, and 77. The main distribution valve 75 is fluidly connected to chambers 63B, 63C, and 63D. The main distribution valve 76 is fluidly connected to chamber 63A.The main distribution valve 77 is fluidly connected to the reservoir 62.

[0097] The distributor 66 may include a hydraulic valve 80 configured to transmit, depending on the operating conditions, lubricant from the pump 64 to the main valve 67 or to the auxiliary valve 68. The valve includes an inlet that is fluidly connected to the outlet of the pump 64. The inlet of the valve can thus receive the entire flow of lubricant pumped by the pump 64. The valve includes two separate outlets. A first outlet is fluidly connected to the inlet of the main valve 67, and a second outlet is fluidly connected to the inlet of the auxiliary valve 68. The valve is configured to fluidly connect the inlet of the valve exclusively to either the first or the second outlet. The valve operates in a binary manner such that: - either the distributor is in a main configuration in which the distributor inlet fluidly connects the pump outlet 64 to the first distributor outlet and the main set inlet 67, - either the distributor is in an auxiliary configuration in which the inlet of the distributor fluidly connects the outlet of the pump 64 to the second outlet of the distributor and the inlet of the auxiliary set 68.

[0098] The switch between the main configuration and the auxiliary configuration of the distributor 80 is controlled according to the operating conditions.

[0099] In a particular embodiment, the distributor 80 comprises a spool 84 movable in one direction between a main position and an auxiliary position. The distributor 80 is configured to transmit lubricant from the pump 62 towards the main game 67 if drawer 84 is in the main position and towards the auxiliary game 68 if drawer 84 is in the auxiliary position.

[0100] In this embodiment, the distributor 80 comprises a fixed part and a spool mounted movable relative to the fixed part. The spool has a translational degree of freedom, that is, it can be moved in translation along a direction of travel. More precisely, the spool can be moved from a main position to an auxiliary position or vice versa from the auxiliary position to the main position. The spool is not configured to remain in an intermediate position located between the auxiliary position and the main position.

[0101] When the drawer 84 is in the main position then the distributor 80 smoothly connects the inlet of the distributor and the first outlet of the distributor 80 connected itself to the main set 67.

[0102] When the drawer 84 is in the auxiliary position then the distributor 80 fluidly connects the inlet of the distributor and the second outlet of the distributor 80 connected itself to the auxiliary set 68.

[0103] The drawer may, for example, comprise two separate conduits. The first conduit is placed in the drawer such that: - if the spool is in the main position then the first conduit fluidly connects the inlet of the distributor and the first outlet of the distributor, and - if the spool is in the auxiliary position then the second conduit fluidly connects the inlet of the distributor and the second outlet of the distributor.

[0104] In relation to the figure, drawer 84 is shown in the auxiliary position.

[0105] In this embodiment, the distributor 80 also includes an actuator 83 configured to move the spool 84 according to the operating conditions. The actuator 83 is configured to exert a force on the spool 84 in the direction of movement of the spool 84. More specifically, the actuator 83 is configured to exert a force in both directions defined by the direction of movement. The force exerted by the actuator 83 is sufficient to move the spool from the main position to the auxiliary position and vice versa, from the auxiliary position to the main position.

[0106] In a first alternative, the actuator 83 is electrically controlled. The actuator can be, in particular, an electric motor configured to move the spool along its axis of travel. For example, a control signal is generated from a measurement taken by a speed sensor on a turbomachine shaft; this control signal is then sent to the motor to control the position of the spool 84.

[0107] In a second alternative, the actuator 83 includes a transmitter 85 configured to exert on the spool 84 a constraint in the direction oriented towards one of the main and auxiliary positions, a value of the constraint depending on the operating mode. In other words, the transmitter 85 is configured to exert a force on the slide 84 directed along the direction in only one of the two directions defined by the direction. Put another way, the transmitter 85 is configured to exert a constraint on the slide 84 exclusively oriented in one direction from the main position to the auxiliary position and not in the other direction, or a constraint exclusively oriented from the auxiliary position to the main position and not in the other direction.

[0108] Such a transmitter is therefore configured to move drawer 84: - exclusively from the main position to the auxiliary position but not in the other direction, or - exclusively from the auxiliary position to the main position but not in the other direction.

[0109] A value of the force exerted by the transmitter 85 on the spool 84 depends on the operating speed. For example, the transmitter 85 is an electric motor configured to move the spool along the direction of travel in only one direction, the electric motor being controlled to exert a force that depends on the operating speed. In another example, the transmitter 85 may be a piston and cylinder assembly, the piston being configured to slide within the cylinder, which is held fixed relative to the fixed part of the distributor 80. The piston slides, for example, along the direction of travel of the spool. The position of the piston in the cylinder may, in particular, depend on a pressure exerted by a working fluid. The working fluid may be a fluid pressurized according to the operating speed of the turbomachine.For example, if pump 64 is driven by a shaft of the turbomachine, then the lubricant pumped by pump 64 has a pressure that is a function of the turbomachine's speed. The transmitter 85 can then include a conduit fluidically connected to a tapping point in the circuit downstream of pump 64, so that lubricant pressurized by pump 64 is brought into contact with a moving surface, the piston's movement depending on the movement of this moving surface. The moving surface can be a surface of the piston itself or a surface rigidly attached to the piston. This is referred to as a "pressure tapping" on the lubrication circuit to provide the hydraulic power required to control actuator 83.

[0110] In this second alternative, the actuator 83 also includes a return member 86 configured to exert a return force on the spool 84 directed towards the other from the main position and the auxiliary position. In other words, the transmitter exerts a force on the spool in only one of the two directions of spool direction, and the return member exerts a force on the spool in the other of the two directions of spool direction. Unlike the transmitter, the return member exerts a force on the spool that is independent of the operating conditions. For example, the return member is made up of by a deformable elastic part in contact with a fixed base, for example the fixed part of the dispenser 80, and an object movable relative to the fixed base, for example the drawer 84 movable relative to the fixed part of the dispenser 80, and which has: - a neutral configuration in which the part does not exert any constraint on the object, and - a constrained configuration in which the part exerts a constraint on the object.

[0111] The elastic deformable part is deformed to change from one configuration to another. In this example, the elastic deformable part is placed in contact with the drawer 84 and is configured to: - be in the neutral configuration when the drawer is in the main position, and - be in the constrained configuration when the drawer is in the auxiliary position.

[0112] The elastic deformable part can be a compressible spring.

[0113] The advantage of the second alternative is that it does not use a sensor and uses a linear displacement motor controlled by a signal constructed from the measurement signal. The lubrication system is simplified.

[0114] It should also be noted that the second alternative is advantageous when the turbomachine is operated in low ambient temperatures. In this case, the lubricant itself is significantly colder than on a normal day, so the lubricant pressure is higher than on a normal day. It is possible that the lubricant pressure may be so high that the valve is placed in the main position even though the turbomachine is not in takeoff mode. In this case, the lubricant circulates more freely in the engine compartments and the mechanism housing, even though the turbomachine is not in takeoff mode. This has the effect of heating the lubricant more quickly than if the valve were in the auxiliary position.As the lubricant temperature increases, the pressure exerted by the lubricant decreases, so that the valve eventually moves to the auxiliary position, with the turbomachine remaining at cruising speed in the interim. This operation maximizes the amount of oil heated by the engine chambers, and the lubricant warm-up time is reduced.

[0115] The lubrication system 60 further includes a scavenging pump 96. The scavenging pump is configured to pump the lubricant located in a chamber 63 so as to extract the lubricant through the chamber outlet and transfer it to the reservoir 62. The scavenging pump 96 can be fluidly connected to the outlet of each of the chambers 63 of the lubrication system 60. The scavenging pump 96 contributes to the proper circulation of the lubricant in the lubrication system 60.

[0116] The lubrication system may also include one or more heat exchangers configured to cool the lubricant to a temperature.

[0117] For example, the lubrication system includes a common heat exchanger 90 configured to cool the lubricant flow from the pump 64 to the distributor 66. The common heat exchanger 90 is then fluidly connected at the inlet to the outlet of the pump 64 and at the outlet to the inlet of the distributor 66. Alternatively, the common heat exchanger can be placed between the discharge pump 96 and the reservoir 62.

[0118] For example, the lubrication system includes a special heat exchanger 92, 94 configured to cool a fraction of the pumped lubricant flow, specifically a fraction of the flow that passes through only some of the enclosures 63. With reference to [Fig. 5], the heat exchanger 92 cools the fraction of the flow that supplies enclosure 63A, and the heat exchanger 94 cools the fraction of the flow that supplies enclosures 63B, 63C, and 63D. These special heat exchangers allow for more targeted cooling to meet the specific needs of one or more enclosures. This makes it possible to supply the enclosures 63 with lubricant whose temperature varies from one enclosure to another. This results in more efficient overall cooling and achieves ideal operating temperatures in each enclosure while minimizing energy consumption.In particular, a special exchanger can be provided, configured to cool the lubricant that supplies the housing which contains the speed reduction mechanism 19. Lubrication method for a turbomachine

[0119] The lubrication system 60, as previously described, allows for the implementation of a turbomachine lubrication process P. Such a process is now described in relation to [Fig. 6].

[0120] In a first step SI, lubricant is pumped from a reservoir of the turbomachine. For example, pump 64 pumps lubricant from reservoir 64.

[0121] In a second step S2, the turbomachine speed is compared to the reference speed. This comparison can be performed by measuring the speed and then using a comparator configured to deliver a control signal to an actuation motor. This comparison step can also be implemented without measurement. For this purpose, a working fluid can be used, i.e., a fluid whose pressure depends on the turbomachine speed. The lubricant flow pumped by the pump can serve as this working fluid if the pump is driven by a turbomachine drive shaft. The working fluid can then be applied against a moving surface configured to resist the fluid pressure as long as the pressure remains below a reference pressure, the reference pressure corresponding to the pressure reached by the working fluid when the turbomachine speed reaches the reference operating conditions. The position of the moving surface then reflects the turbomachine's operating conditions relative to the reference operating conditions. The position of the moving surface thus corresponds to a form of comparison between the turbomachine's operating conditions and the reference operating conditions.

[0122] In a third step S3, parts of the turbomachine housed in two enclosures of the turbomachine are lubricated, the lubrication being carried out according to a main configuration if a turbomachine regime is beyond the reference regime and according to an auxiliary configuration otherwise.

[0123] In the main configuration, the pumped lubricant is transmitted to both chambers and only to both chambers. The lubricant flow is transmitted to the chambers according to the main distribution proportions.

[0124] In the auxiliary configuration, the pumped lubricant is transmitted to the two enclosures and to the reservoir according to the auxiliary distribution proportions.

[0125] This lubrication can be implemented in different ways. The lubricant flow can, for example, pass through the distributor 66, which includes the main set 67, the auxiliary set 68, and the distributor 80. The distributor transmits the lubricant flow to the main set 67 if the turbomachine speed is above the reference speed and to the auxiliary set 68 otherwise.

[0126] When the distributor includes the movable spool 84, the spool 84 is actuated to a position between the main position and the auxiliary position depending on the turbomachine speed. If the spool 84 is electrically actuated, for example by a motor, an electrical control signal generated from the sensor measurement can be used to actuate the position of the spool 84. If the spool 84 is hydraulically controlled, the movement of a movable surface against which the operating fluid is applied, such as the lubricant flow as in the previously mentioned example, can be used to move the spool 84 in a first direction from the auxiliary position to the main position if the speed is above the reference speed. In this case, the return element moves the spool 84 in the second direction, opposite to the first direction, from the main position to the auxiliary position if the speed is below the reference speed.

[0127] In an optional substep S3-1 included in step S3, the lubricant flow pumped by the pump is cooled before it supplies the enclosures 63. The common heat exchanger 90 as described above can perform this substep, which consists of cooling the entire lubricant flow pumped by the pump 64.

[0128] In an optional substep S3-2 included in step S3, only a part of the lubricant flow pumped by the pump is cooled before it supplies only a part of the enclosures 63. The particular heat exchanger 92 or 94 as described above can perform this substep.

[0129] In a fourth step S4, the lubricant transmitted into the enclosures via the enclosure outlets is extracted and transmitted to the reservoir 62. The evacuation pump 96 can pump the lubricant from all the enclosures and convey it to the reservoir 62.

[0130] Method for sizing the lubrication system

[0131] In relation to [Fig.7], a method Q for dimensioning the lubrication system is presented as previously described.

[0132] In the case where the turbomachine includes a reduction mechanism and an enclosure 63A configured to house the reduction mechanism, the lubrication system can be dimensioned according to the following steps.

[0133] In a first step El, the reference regime is identified, a first regime beyond the reference regime, for example the regime reached when the aircraft is in takeoff or cruise phase, and a second regime below the reference regime, for example the regime reached when the aircraft is in engine idle phase.

[0134] In a second step E2, the following information is provided: - the maximum acceptable temperature (Tl) of the lubricant for cooling the reduction mechanism, - the required lubricant flow rate to cool the reduction mechanism for the first operating mode (Qld, called "first flow rate") on the one hand and for the second operating mode (Qlc, called "second flow rate") on the other hand, - the maximum acceptable temperature (T2) of the lubricant for cooling the engine compartments, - the required lubricant flow rate for the other chambers for the first regime (Q2d, also called "third flow rate") on the one hand, and for the second regime (Q2c, also called "fourth flow rate") on the other hand, - the necessary distribution of the lubricant flow rate between the engine chambers.

[0135] In a third step E3, a supply pump is selected, configured to deliver, in the first operating range, a lubricant flow rate greater than or equal to the maximum flow rate required to supply the reduction mechanism chamber and the other chambers in the first operating range. In other words, the pump is selected, configured to deliver a lubricant flow rate greater than the sum of the first and third flow rates Qld+Q2d.

[0136] In a fourth step E4, the nozzles of the different engine chambers are sized and in particular the opening diameters of these different nozzles so that by supplying them in parallel from a single inlet receiving a flow of lubricant, the distribution of the flows in the different chambers corresponds to the necessary distribution.

[0137] In a fifth step E5, a common exchanger and at least one particular exchanger are chosen so that the oil temperature constraints are respected so that the temperature of the lubricant sent into the enclosure of the reduction mechanism is less than the temperature T1 and so that the temperature of the lubricant sent into the engine enclosures is less than the temperature T2.

[0138] In a sixth step E6, the main distribution valves are sized so that the lubricant flow extracted from the reservoir by the pump in the first operating mode is distributed according to, on the one hand, the first flow rate Qld towards the reduction mechanism and, on the other hand, the third flow rate Q2d towards the other chambers. In other words, the main distribution proportions are set at Qld / (Qld+Q2d) for the chamber of the reduction mechanism and at Q2d / (Qld+Q2d) for the other chambers.

[0139] In a seventh step E7, the flow rate Qc of lubricant extracted from the reservoir by the pump in the second operating mode is evaluated. This flow rate differs, in particular, from the flow rate extracted by the pump in the first operating mode if the pump is driven by a shaft of the turbomachine. This lubricant flow rate is compared to the sum of the second and fourth flow rates Qlc+Q2c required to cool the reduction mechanism (Qlc) and the other enclosures (Q2c) in the second operating mode.

[0140] In an eighth step E8, the auxiliary flow rate to the reservoir (Qr) is determined, corresponding to a difference between the flow rate of lubricant extracted from the reservoir by the pump in the second regime and the sum of the second flow rate and the fourth flow rate Qlc+Q2c required in the second regime for the reduction mechanism (Qlc) and the other enclosures (Q2c), i.e. Qr=Qc-(Qlc+Q2c)

[0141] In a ninth step E9, the auxiliary distribution valves are sized so that the lubricant flow extracted from the reservoir by the pump in the second operating mode is distributed between the reservoir, the reduction mechanism, and the other enclosures. In other words, the auxiliary distribution proportions are determined as follows: - the proportion of auxiliary distribution associated with the reservoir is equal to (Qc-(Qlc+Q2c)) / Qc; - the proportion of auxiliary allocation associated with the reduction mechanism is equal to Qlc / Qc; and - the proportion of auxiliary distribution associated with the other speakers is equal to Q2c / Qc.

Claims

Demands

1. Lubrication system (60) of a turbomachine, the system comprising: - several enclosures (63) each suitable for housing at least one part of the turbomachine to be lubricated, - a lubricant reservoir (62), - a pump (64) configured to pump lubricant contained in the reservoir (62), - a distributor (66) configurable in a main configuration if a turbomachine speed is above a reference speed and in an auxiliary configuration otherwise, the distributor (66) being configured in the auxiliary configuration to transmit lubricant from the pump (64) to the enclosures (63) and to the reservoir (62) in constant auxiliary distribution proportions, the distributor (66) being configured in the main configuration to transmit lubricant from the pump (64) to only the enclosures (63) in constant main distribution proportions.

2. System according to claim 1 wherein a ratio of an auxiliary distribution proportion associated with a first of the speakers to an auxiliary distribution proportion associated with a second of the speakers is different from a ratio of a main distribution proportion associated with the first of the speakers to a main distribution proportion associated with the second of the speakers.

3. System according to any one of claims 1 and 2 wherein the distributor (66) comprises: - a main set (67) of valves in which each valve is fluidly connected to one of the enclosures (63), - an auxiliary set of valves (68) in which one of the valves is fluidly connected to the reservoir (62) and each of the other valves is fluidly connected to one of the enclosures (63), and - a distributor (80) configured to transmit, depending on the turbomachine speed, lubricant from the pump (64) to the main set (67) or to the auxiliary set (68).

4. System according to claim 3 wherein the distributor (80) comprises - a spool (84) mounted movable in a direction between a main position and an auxiliary position, the distributor (80) being configured to transmit lubricant from the pump (62) to the main set (67) if the spool (84) is in the main position and to the auxiliary set (68) if the spool (84) is in the auxiliary position, and - an actuator (83) configured to move the spool (84) according to the speed.

5. System according to claim 4 in which the actuator (83) comprises: - a transmitter (85) configured to exert on the spool (84) a constraint in the direction oriented towards one of the main position and the auxiliary position, a value of the constraint depending on the regime, and - a return member (86) configured to exert on the spool (84) a return oriented towards the other of the main position and the auxiliary position.

6. System according to any one of claims 1 to 5 configured to circulate a flow of lubricant from the pump to the distributor and a fraction of the flow from the distributor to only a portion of the enclosures, the system comprising: - a common exchanger (90) configured to cool the flow, and - a particular exchanger (92, 94) configured to cool the fraction of the flow.

7. Turbomachine comprising a lubrication system according to any one of claims 1 to 6.

8. Turbomachine according to claim 7 comprising a blower, a drive shaft and a speed reduction mechanism configured to be driven in rotation by the drive shaft and to drive in rotation the blower, the enclosures (63) of the lubrication system comprising an enclosure (63A) housing the speed reduction mechanism.

9. Aircraft comprising a turbomachine according to any one of claims 7 and 8.

10. A method for sizing a lubrication system for a turbomachine according to claim 8, the method comprising the following steps: - (El) identification of the reference regime, a first regime beyond the reference regime and a second regime below the reference regime, - (E2) for the enclosure (63A) housing the speed reduction mechanism, identification of a first required lubricant flow rate (Qld) for the first regime and a second required lubricant flow rate (Qlc) for the second regime, and for the other enclosures (63B, 63C, 63D) identification of a third required lubricant flow rate (Q2d) for the first regime and a fourth required lubricant flow rate (Q2c) for the second regime, - (E3) determination of a pump configured to deliver In the first regime, a lubricant flow greater than or equal to the main flow rate (Qld+Q2d) equal to the sum of the first flow rate and the third flow rate, - (E6) determination of a distribution proportion main associated with the reduction mechanism corresponding to the ratio of the first flow rate (Qld) to the main flow rate (Qld+Q2d) and a main distribution proportion associated with the other enclosures corresponding to the ratio of the third flow rate (Q2d) to the main flow rate (Qld+Q2d), - (E7) determination of an auxiliary flow rate (Qc) extracted from the reservoir via pump in the second regime - (E8) determination of an auxiliary flow rate to the reservoir (Qr) corresponding to a difference between the auxiliary flow rate (Qc) and the sum of the second flow rate (Qlc) and the fourth flow rate (Q2c), and - (E9) determination of an auxiliary distribution proportion associated with the reservoir corresponding to the ratio of the auxiliary flow to the reservoir (Qr) on the auxiliary flow (Qc), of an auxiliary distribution proportion associated with the reduction mechanism corresponding to the ratio of the second flow (Qlc) on the auxiliary flow (Qc) and of an auxiliary distribution proportion associated with the other enclosures corresponding to the ratio of the fourth flow (Q2c) on the auxiliary flow (Qc).

11. A method for lubricating a turbomachine, the method comprising: - a step involving pumping lubricant contained in a turbomachine reservoir, and - a stage of lubrication of parts of the turbomachine, the parts being housed in several enclosures of the turbomachine, the lubrication being carried out according to a main configuration if a turbomachine regime is beyond a reference regime and according to an auxiliary configuration otherwise, the pumped lubricant being transmitted in the auxiliary configuration to the two enclosures and to the reservoir according to constant auxiliary distribution proportions, the pumped lubricant being transmitted in the main configuration to only the two enclosures and according to constant main distribution proportions.

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