FR3163405A1 - Lubrication system for the housings of a turbomachine - Google Patents

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

Lubrication system for the housings of a turbomachine DOMAIN

The invention relates to a lubrication system for the housings of a turbomachine, in particular a turbomachine exhibiting at least two operating regimes, the lubricant distribution requirement between the housings varying significantly from one regime to the other. In what follows, the term "operating regime," or simply "regulation," 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

In a turbomachine, the lubricant supply not only lubricates but also, and more importantly, cools components such as bearings, bushings, and gears. These components are housed in various enclosures, including one or more engine enclosures and possibly an accessory gearbox (AGB), or even a reduction gearbox (RGB) containing a speed reduction mechanism. The lubrication system is configured to distribute the lubricant flow among these different enclosures. In a conventional turbomachine, this distribution of the lubricant is constant and does not vary with the turbomachine's operating speed.

In some cases, the required lubricant distribution for the proper lubrication and cooling of the lubricated components within the chambers varies significantly depending on the operating conditions. A constant distribution of the distributed lubricant in these cases results in an oversupply of lubricant to at least one chamber at at least one operating condition. The affected chamber(s) then risk being "flooded" with 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 components.

Therefore, there is a need for a turbomachine enclosure lubrication system that better takes into account the distribution between enclosures of the required lubricant flow rate, which varies according to the turbomachine's operating conditions.

PRESENTATION OF THE DRAWINGS

Other features and advantages will become clearer from the following description, which is purely illustrative and not exhaustive, and should be read in conjunction with the attached figures, including:

- there FIG. 1 schematically represents an aircraft including propulsion systems.

- there FIG. 2 schematically represents, in partial view and in cross-section, an example of a propulsion system

- there FIG. 3 schematically represents a first example of a planetary reduction mechanism,

- there FIG. 4 schematically represents a first example of an epicycloidal reduction mechanism.

- there FIG. 5 schematically represents a lubrication system for a turbomachine.

- there FIG. 6 schematically represents a lubrication process for a turbomachine, and

- there FIG. 7 schematically represents a method for sizing a lubrication system for a turbomachine.

EXPOSED

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

The goal is achieved through a turbomachine lubrication system, the system comprising:

- several separate enclosures, each designed to house at least one part of the turbomachine to be lubricated,

- a lubricant reservoir,

- a pump configured to pump lubricant from the reservoir,

- a distributor configurable in a main configuration if a turbomachine speed is beyond a reference speed 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 according to constant auxiliary distribution proportions, the distributor being configured in the main configuration to transmit lubricant from the pump to only the enclosures according to constant main distribution proportions.

• un rapport d’une proportion de répartition auxiliaire associée à une première des enceintes sur une proportion de répartition auxiliaire associée à une deuxième des enceintes est différent d’un rapport d’une proportion de répartition principale associée à la première des enceintes sur une proportion de répartition principale associée à la deuxième des enceintes ;

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 a first speaker to an auxiliary distribution proportion associated with a second speaker is different from a ratio of a main distribution proportion associated with the first speaker to a main distribution proportion associated with the second speaker;

- the distributor includes 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;

- the distributor includes a spool mounted movable in one 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;

- the actuator comprises a transmitter configured to exert a force on the spool in the direction oriented towards one of the main and auxiliary positions, the value of the force depending on the operating conditions, and a return element configured to exert a return force on the spool oriented towards the other of the main and auxiliary positions; and

- 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 chambers, the system comprising a common exchanger configured to cool the flow, and a particular exchanger configured to cool the fraction of the flow.

The presentation also covers a turbomachine including a lubrication system as described above.

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.

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

The presentation also covers a method for sizing a lubrication system for a turbomachine, previously presented in its version supplemented by a fan, a drive shaft, and a speed reduction mechanism. This method comprises the following steps:

- (E1) identification of the reference scheme, a first scheme beyond the reference scheme and a second scheme below the reference scheme,

• (E3) détermination d’une pompe configurée pour délivrer dans le premier régime un flux de lubrifiant supérieur ou égal au débit principal (Q1d+Q2d) égal à la somme du premier débit et du troisième débit,
• (E6) détermination d’une proportion de répartition principale associée au mécanisme de réduction correspondant au rapport du premier débit (Q1d) sur le débit principal (Q1d+Q2d) et d’une proportion de répartition principale associée aux autres enceintes correspondant au rapport du troisième débit (Q2d) sur le débit principal (Q1d+Q2d),
• (E7) détermination d’un débit auxilaire (Qc) extrait du réservoir par la pompe dans le deuxième régime,
• (E8) détermination d’un débit auxiliaire vers le réservoir (Qr) correspondant à une différence entre le débit auxiliaire (Qc) et la somme du deuxième débit (Q1c) et du quatrième débit (Q2c), et
• (E9) détermination d’une proportion de répartition auxilaire associée au réservoir correspondant au rapport du débit auxiliaire vers le réservoir (Qr) sur le débit auxiliaire (Qc), d’une proportion de répartition auxilaire associée au mécanisme de réduction correspondant au rapport du deuxième débit (Q1c) sur le débit auxiliaire (Qc) et d’une proportion de répartition auxiliaire associée aux autres enceintes correspondant au rapport du quatrième débit (Q2c) sur le débit auxiliaire (Qc).

- (E2) for the enclosure housing the speed reduction mechanism, identification of a first required lubricant flow rate (Q1d) for the first regime and a second required lubricant flow rate (Q1c) 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 regime a lubricant flow greater than or equal to the main flow rate (Q1d+Q2d) equal to the sum of the first flow rate and the third flow rate,
• (E6) determination of a main distribution proportion associated with the reduction mechanism corresponding to the ratio of the first flow rate (Q1d) to the main flow rate (Q1d+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 (Q1d+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 reservoir (Qr) corresponding to a difference between the auxiliary flow rate (Qc) and the sum of the second flow rate (Q1c) 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) to the auxiliary flow (Qc), of an auxiliary distribution proportion associated with the reduction mechanism corresponding to the ratio of the second flow (Q1c) to the auxiliary flow (Qc) and of an auxiliary distribution proportion associated with the other enclosures corresponding to the ratio of the fourth flow (Q2c) to the auxiliary flow (Qc).

• une étape de pompage de lubrifiant contenu dans un réservoir de la turbomachine, et
• une étape de lubrification de pièces de la turbomachine, les pièces étant logées dans plusieurs enceintes de la turbomachine, la lubrification s’effectuant selon une configuration principale si un régime de la turbomachine est au-delà d’un régime de référence et selon une configuration auxiliaire sinon, le lubrifiant pompé étant transmis dans la configuration auxiliaire vers les deux enceintes et vers le réservoir selon des proportions de répartition auxiliaire constantes, le lubrifiant pompé étant transmis dans la configuration principale vers seulement les deux enceintes et selon des proportions de répartition principale constantes.

The presentation concludes with a lubrication process for a turbomachine, the process comprising:

• a step of pumping lubricant contained in a reservoir of the turbomachine, and
• a turbomachine parts lubrication stage, the parts being housed in several turbomachine enclosures, 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.

DETAILED DESCRIPTION OF A METHOD OF IMPLEMENTATION Turbomachine

In the example shown on the FIG. 1 The aircraft is an airplane 100 comprising a fuselage 101 and two wings 102. In this example, the aircraft includes 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 include one or more propulsion system(s) attached to the fuselage 101.

There FIG. 2 represents schematically, in partial view and in cross-section, an example of a propulsion system 1.

In this example, the propulsion system 1 is a twin-shaft gas turbine engine with a shrouded fan. It should be noted that this description is not limited to this engine example 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.

On the FIG. 2 The propulsion system 1 has a main direction extending along a longitudinal axis X. The propulsion system 1 includes a blower section 2 and a primary body 3, often called a "gas generator".

The blower section 2 includes a blower 22 and a blower housing 12. The blower 22 includes a blower rotor 9. The blower housing 12 surrounds the blower rotor 9. The blower rotor 9 is mounted to rotate relative to the blower housing 12.

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.

Furthermore, in this example, the fan section 2 also includes a fan stator 16 fixedly mounted on the fan housing 12. The fan stator 16 comprises fixed blades 17, commonly referred to as outlet guide vanes (OGVs). This set of fixed blades serves to straighten and regulate the airflow downstream of the fan rotor 9 to contribute to engine thrust. This set of fixed blades can also act as a noise reducer.

Alternatively, the outlet blades 17 could have 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.

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

Compressor section 29 includes a low pressure compressor 4 and a high pressure compressor 5.

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.

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

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.

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.

Turbine section 30 includes a high-pressure turbine 7 and a low-pressure turbine 8.

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

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.

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.

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.

Turbine section 30 includes a high-pressure turbine 7 and a low-pressure turbine 8.

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

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.

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.

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

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 to rotate relative to the housing 31 around the longitudinal axis X.

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.

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.

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.

The reduction mechanism 19 thus allows independent control of the rotation speed of the blower 22 and the rotation speed of the low pressure turbine 8 and the low pressure compressor 4.

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.

The propulsion system 1 further includes 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 mounted to rotate relative to the housing 31 around 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.

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 11.

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.

The low-pressure shaft 11 and the high-pressure shaft 10 can be co-rotating, i.e., 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, i.e., driven in opposite directions of rotation around the longitudinal axis X.

The twin-spool propulsion system 1 may include, in particular, 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 the FIG. 2 ).

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 F1 and a secondary airflow F2, which flow upstream to downstream in the propulsion system 1.

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.

The primary airflow F1 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 of the primary airflow F1 through the turbine section 30, receiving energy from the combustion chamber 6, causes the rotating impellers 7a, 8a of the turbine section 30 to rotate, which in turn drives the rotating impellers 4a, 5a of the compressor section 29 as well as the blower rotor 9.

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

For example, the 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 in rotation the blower shaft 20 around 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.

In another example, the 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.

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

In relation to the 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.

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

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

The 63 enclosures are lubrication chambers designed for installation in the turbomachine. The 63 enclosures include a lubricant inlet and a lubricant outlet. The 63 enclosures are configured to receive a flow of lubricant through the inlet and allow it to flow to the outlet. The 63 enclosures are sealed in the sense that the mass flow rate of the lubricant is maintained between their inlet and outlet. In particular, the lubricant does not flow outside the enclosure into an adjacent enclosure. The sealing of the enclosures can be achieved, among other things, by means of gaskets.

The lubrication system comprises at least two enclosures 63. For example, the enclosures 63 may include a reduction gear enclosure 63A, which houses the reduction mechanism 19 when present in the propulsion system. The enclosures 63 may also include motor enclosures 63B and 63C, each motor enclosure housing some of the bearings and bushings that ensure the proper operation of the blower on the motor shaft(s). The enclosures 63 may further include an accessory box enclosure 63D, which houses the accessory box.

The lubrication system 60 includes a pump 64 configured to extract lubricant from the reservoir and deliver it to the enclosures 63. The pump 64 is therefore 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 delivered to various sub-parts of the lubrication system 60, such as the enclosures 63.

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.

The distributor 66 is configurable in a main configuration if a turbomachine speed is beyond a reference speed and in an auxiliary configuration otherwise.

The operating speed of a turbomachine corresponds, for example, to the rotational speed of a drive shaft of the turbomachine, such as the high-pressure shaft when present. A reference operating speed is, for example, a predetermined rotational speed.

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

The distributor is configured in the primary 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 primary distribution proportions. Each chamber is associated with a primary distribution proportion. For example, if the lubrication system has two chambers, a first primary distribution proportion can be associated with one of the two chambers, and a second primary 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 primary distribution proportion corresponds to the ratio of the lubricant flow entering the second cavity to the total lubricant flow from the pump 64. The sum of the first and second primary distribution proportions is equal to 1, or 100%.

The fact that the main distribution proportions are constant means that they do not depend on the turbomachine's operating conditions. Lubricant is transferred to the cavities 63 according to constant main distribution proportions as long as the distributor 66 is in its main configuration.

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 two parts: one portion is transferred to the chambers only, and the other portion is transferred to the reservoir 62. The transfer of lubricant from the distributor 66 to the reservoir 62 is understood here as direct, meaning that the lubricant flow passes from the distributor 66 to the reservoir 62 solely 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, if the lubrication system comprises two cavities, a first auxiliary distribution proportion can be associated with the first of the two chambers, and a second primary auxiliary distribution proportion with the second of the two chambers. The first proportion corresponds to the ratio of the lubricant flow entering the first cavity to the total lubricant flow from pump 64. The second 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 auxiliary distribution proportion, the second auxiliary distribution proportion, and the auxiliary distribution proportion associated with the reservoir is equal to 1 or 100%.

The fact that the auxiliary distribution proportions are constant means that they do not depend on the turbomachine's operating conditions. Lubricant is transferred to the cavities 63 and the reservoir according to constant auxiliary distribution proportions as long as the distributor 66 is in the auxiliary configuration.

The distributor allows for two operating modes of the lubrication system. In the primary mode, all the pumped lubricant is distributed among 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 a second mode, only a portion of the pumped lubricant is distributed among the chambers, with 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 second mode is activated, for example, when the aircraft is at engine idle. This allows for a variable distribution of the lubricant flow at the pump outlet, depending on the turbomachine speed. In the auxiliary configuration, this notably reduces the proportion of lubricant flow that feeds chambers 63. This limits the risk of over-supplying chambers 63.

It is worth noting that imposing constant primary distribution proportions and constant auxiliary distribution proportions gives the distributor a binary character. This allows for 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 components, ultimately leading to higher costs and potentially reduced reliability.

Furthermore, it can be predicted that the ratio of an auxiliary distribution proportion associated with the first chamber to an auxiliary distribution proportion associated with the second chamber will differ from the ratio of a primary distribution proportion associated with the first chamber to a primary distribution proportion associated with the second chamber. In this case, the lubricant flow distribution between the chambers varies according to the turbomachine's operating conditions. This allows for even finer adjustment of the flows delivered to each chamber, further limiting the risk of lubricant oversupply within the chambers.

To implement the switch from the main to the auxiliary configuration, the lubrication system may include a sensor configured to measure the turbomachine speed. The distributor 66 is 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 it in either the main or auxiliary configuration.

In the case where 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 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 this pressure constraint to construct a control signal for the distributor.

In relation to the FIG. 5 , the distributor 66 can include two sets of lubricant flow distribution valves.

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

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 valve set's inlet. An incident flow of lubricant can be sent to the valve set's inlet. Each valve can be adjusted to allow more or less lubricant to flow to the outlet. This makes it possible to control the distribution of the incident flow at the outlet of the different valves.

The distributor 66 may include a first set of valves, called 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 the FIG. 5 The lubrication system comprises four chambers 63A, 63B, 63C, and 63D, and the main set 67 includes 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.

The distributor 66 may include a second set of valves, called the auxiliary set 68, in which one valve 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 the FIG. 5 The main set 68 includes the main distribution valves 75, 76, and 77. The main distribution valve 75 is fluidly connected to enclosures 63B, 63C, and 63D. The main distribution valve 76 is fluidly connected to enclosure 63A. The main distribution valve 77 is fluidly connected to reservoir 62.

• soit le distributeur est dans une configuration principale dans laquelle l’entrée du distributeur connecte fluidiquement la sortie de la pompe 64 à la première sortie du distributeur et l’entrée du jeu principal 67,
• soit le distributeur est dans une configuration auxiliaire dans laquelle l’entrée du distributeur connecte fluidiquement la sortie de la pompe 64 à la deuxième sortie du distributeur et l’entrée du jeu auxiliaire 68.

The distributor 66 may include a hydraulic valve 80 configured to transmit, depending on the engine speed, 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 valve inlet 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 valve inlet exclusively to either the first or 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.

The switch between the main configuration and the auxiliary configuration of distributor 80 is controlled according to the engine speed.

In a particular embodiment, the distributor 80 includes 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 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.

In this embodiment, the distributor 80 comprises a fixed part and a spool mounted to move relative to the fixed part. The spool has one degree of translational freedom, meaning it can be moved in a direction of travel. More precisely, the spool can be moved from a primary position to an auxiliary position or vice versa, from the auxiliary position to the primary position. The spool is not configured to remain in an intermediate position between the auxiliary and primary positions.

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.

When the drawer 84 is in the auxiliary position, then the distributor 80 smoothly connects the inlet of the distributor and the second outlet of the distributor 80, which is itself connected to the auxiliary set 68.

• si le tiroir est en position principale alors le premier conduit connecte fluidiquement l’entrée du distributeur et la première sortie du distributeur, et
• si le tiroir est en position auxiliaire alors le deuxième conduit connecte fluidiquement l’entrée du distributeur et la deuxième sortie du distributeur.

The drawer may, for example, include 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 smoothly connects the inlet of the distributor and the first outlet of the distributor, and
• If the drawer is in the auxiliary position, then the second conduit smoothly connects the inlet of the distributor and the second outlet of the distributor.

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

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 its movement. More precisely, 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.

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 of a turbomachine shaft; this control signal is then sent to the motor to control the position of the spool 84.

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

• exclusivement de la position principale à la position auxiliaire mais pas dans l’autre sens, ou
• exclusivement de la position auxiliaire à la position principale mais pas dans l’autre sens.

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.

The value of the force exerted by the transmitter 85 on the spool 84 depends on the engine 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 is dependent on the engine speed. In another example, the transmitter 85 can 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, in the direction of travel of the spool. The position of the piston in the cylinder can depend, in particular, on a pressure exerted by a working fluid. The working fluid can be a fluid pressurized according to the engine speed of the turbomachine. For example, if the pump 64 is driven by a shaft of the turbomachine, then the lubricant pumped by the pump 64 has a pressure that is a function of the engine speed. The transmitter 85 may then include a conduit fluidically connected to a tapping point in the circuit downstream of the pump 64, so that lubricant pressurized by the pump 64 is brought into contact with a moving surface, the movement of the piston depending on the movement of the moving surface. The moving surface may 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 the actuator 83.

• une configuration neutre dans laquelle la pièce n’exerce pas de contrainte sur l’objet, et
• une configuration contrainte dans laquelle la pièce exerce une contrainte sur l’objet.

In this second alternative, the actuator 83 also includes a return element 86 configured to exert a return force on the spool 84 directed towards the other side of the main and auxiliary positions. In other words, the transmitter exerts a force on the spool in only one of the two directions of spool direction, and the return element exerts a force on the spool in the other of the two directions of spool direction. Unlike the transmitter, the return element exerts a force on the spool that is independent of the operating conditions. For example, the return element consists of a deformable elastic part in contact with a fixed base, for example, the fixed part of the distributor 80, and an object movable relative to the fixed base, for example, the spool 84 movable relative to the fixed part of the distributor 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.

• être dans la configuration neutre lorsque le tiroir est dans la position principale, et
• être dans la configuration contrainte lorsque le tiroir est dans la position auxiliaire.

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:

• to be in the neutral configuration when the drawer is in the main position, and
• to be in the constrained configuration when the drawer is in the auxiliary position.

The elastic deformable part can be a compressible spring.

The advantage of the second alternative is that it does not use a sensor and instead uses a linear motion motor controlled by a signal derived from the measurement signal. The lubrication system is simplified.

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, resulting in a higher lubricant pressure. This higher pressure may even cause the valve to move to the primary position, even though the turbomachine is not in takeoff mode. In this scenario, the lubricant circulates more freely within the engine and mechanism housings, even though the turbomachine is not in takeoff mode. This causes the lubricant to heat up more quickly than if the valve were in the auxiliary position. As the lubricant temperature increases, the pressure exerted by the lubricant decreases, eventually leading the valve to move to the auxiliary position, while the turbomachine remains in cruising mode. This operation maximizes the amount of oil heated by the engine housings and reduces the lubricant warm-up time.

The lubrication system 60 further includes a scavenging pump 96. The scavenging pump is configured to pump the lubricant from 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 within the lubrication system 60.

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

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.

For example, the lubrication system includes a special heat exchanger 92, 94 configured to cool a fraction of the pumped lubricant flow, and in particular a fraction of the flow that passes through only a portion of the enclosures 63. With reference to the FIG. 5 Heat exchanger 92 cools the portion of the flow supplying chamber 63A, and heat exchanger 94 cools the portion of the flow supplying chambers 63B, 63C, and 63D. These specialized heat exchangers allow for more targeted cooling to meet the specific needs of a particular chamber or section of chambers. This enables the chambers 63 to be supplied with a lubricant whose temperature varies from one chamber to another. This results in more efficient overall cooling and achieves ideal operating temperatures in each chamber while minimizing energy consumption. In particular, a dedicated heat exchanger can be configured to cool the lubricant supplying the chamber housing the speed reduction mechanism 19.

Lubrication method for a turbomachine

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 the FIG. 6 .

In the first step S1, lubricant is pumped from a reservoir in the turbomachine. For example, pump 64 pumps lubricant from reservoir 64.

In a second step, S2, the turbomachine's operating speed is compared to the reference operating speed. This comparison can be performed by measuring the operating speed and then using a comparator configured to deliver a control signal to an actuation motor. Alternatively, this comparison step can be implemented without measurement. For this purpose, a working fluid can be used, i.e., a fluid whose pressure depends on the turbomachine's operating 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 corresponds to the pressure reached by the working fluid when the turbomachine's operating speed reaches the reference speed. The position of the moving surface then reflects the turbomachine's operating speed relative to the reference speed. The position of the moving surface thus represents a form of comparison between the turbomachine's operating speed and the reference speed.

In a third stage 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.

In the primary configuration, the pumped lubricant is delivered to both chambers and only to both chambers. The lubricant flow is delivered to the chambers according to the primary distribution proportions.

In the auxiliary configuration, the pumped lubricant is transmitted to the two chambers and to the reservoir according to the auxiliary distribution proportions.

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

When the distributor includes the movable spool 84, the spool 84 is actuated to a position between the main and auxiliary positions depending on the turbomachine's operating 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 described in the previous example, can be used to move the spool 84 in a first direction from the auxiliary position to the main position if the operating speed is above the reference speed. In this case, the return mechanism moves the spool 84 in the second direction, opposite to the first, from the main position to the auxiliary position if the operating speed is below the reference speed.

In an optional sub-step 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 previously can perform this sub-step which consists of cooling the entire lubricant flow pumped by the pump 64.

In an optional sub-step 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 exchanger 92 or 94 as described above can perform this sub-step.

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

Lubrication system sizing method

In relation to the FIG. 7 We present a Q method for sizing the lubrication system as previously described.

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 sized according to the following steps.

In a first step E1, we identify the reference regime, 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.

• la température maximale (T1) acceptable du lubrifiant pour refroidir le mécanisme de réduction,
• le débit nécessaire de lubrifiant pour refroidir le mécanisme de réduction pour le premier régime (Q1d, dit « premier débit ») d’une part et pour le deuxième régime (Q1c dit « deuxième débit ») d’autre part,
• la température maximale (T2) acceptable du lubrifiant pour refroidir les enceintes moteur,
• le débit nécessaire de lubrifiant pour les autres enceintes pour le premier régime (Q2d dit « troisième débit ») d’une part et pour le deuxième régime (Q2c dit « quatrième débit ») d’autre part,
• la répartition nécessaire du débit de lubrifiant entre les enceintes moteur.

In a second step E2, the following information is provided:

• the maximum acceptable temperature (T1) of the lubricant for cooling the reduction mechanism,
• the required lubricant flow rate to cool the reduction mechanism for the first operating mode (Q1d, referred to as "first flow rate") on the one hand and for the second operating mode (Q1c, referred to as "second flow rate") on the other hand,
• the maximum acceptable temperature (T2) of the lubricant for cooling engine enclosures,
• 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 lubricant flow between the engine compartments.

In a third step E3, a supply pump is selected, configured to deliver, in the first operating mode, a lubricant flow greater than or equal to the maximum flow rate required to supply the reduction mechanism housing and the other housings in the first operating mode. 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 Q1d+Q2d.

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.

In a fifth step E5, a common exchanger and at least one specific 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.

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 as follows: first, the initial flow rate Q1d to the reduction mechanism, and second, the third flow rate Q2d to the other chambers. In other words, the main distribution proportions are set to Q1d/(Q1d+Q2d) for the reduction mechanism chamber and to Q2d/(Q1d+Q2d) for the other chambers.

In a seventh step E7, the flow rate Qc of lubricant extracted from the reservoir by the pump in the second operating regime is evaluated. This flow rate differs from the flow rate extracted by the pump in the first operating regime 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 Q1c+Q2c required to cool the reduction mechanism (Q1c) and the other enclosures (Q2c) in the second operating regime.

In an eighth step E8, the auxiliary flow to the reservoir (Qr) is determined, corresponding to a difference between the flow of lubricant extracted from the reservoir by the pump in the second regime and the sum of the second flow and the fourth flow Q1c+Q2c required in the second regime the reduction mechanism (Q1c) and the other enclosures (Q2c), i.e. Qr=Qc-(Q1c+Q2c)

• la proportion de répartition auxiliaire associée au réservoir est égale à (Qc-(Q1c+Q2c))/Qc ;
• la proportion de répartition auxiliaire associée au mécanisme de réduction est égale à Q1c/Qc ; et
• la proportion de répartition auxiliaire associée aux autres enceintes est égale à Q2c/Qc.

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-(Q1c+Q2c))/Qc;
• the proportion of auxiliary allocation associated with the reduction mechanism is equal to Q1c/Qc; and
• the proportion of auxiliary distribution associated with the other speakers is equal to Q2c/Qc.

Claims (11)

Lubrication system (60) of a turbomachine, the system comprising:
- several enclosures (63), each designed to house 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 regime is beyond a reference regime 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) according to constant auxiliary distribution proportions, the distributor (66) being configured in the main configuration to transmit lubricant from the pump (64) only to the enclosures (63) according to constant main distribution proportions. 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. A 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). System according to claim 3 in which the distributor (80) comprises
- a spool (84) mounted movable in one 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 drawer (84) according to the regime. System according to claim 4 in which the actuator (83) comprises:
- a transmitter (85) configured to exert a force on the spool (84) in the direction oriented towards one of the main and auxiliary positions, the value of the force depending on the operating conditions, and
- a return member (86) configured to exert on the drawer (84) a return directed towards the other of the main position and the auxiliary position. A 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 chambers, the system comprising:
- a common heat exchanger (90) configured to cool the flow, and
- a particular exchanger (92, 94) configured to cool the fraction of the flow. Turbomachine comprising a lubrication system according to any one of claims 1 to 6. 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. Aircraft comprising a turbomachine according to any one of claims 7 and 8. Method for sizing a lubrication system for a turbomachine according to claim 8, the method comprising the following steps:
- (E1) identification of the reference scheme, a first scheme beyond the reference scheme and a second scheme below the reference scheme,
- (E2) for the enclosure (63A) housing the speed reduction mechanism, identification of a first required lubricant flow rate (Q1d) for the first regime and a second required lubricant flow rate (Q1c) 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 (Q1d+Q2d) equal to the sum of the first flow rate and the third flow rate,
• (E6) determination of a main distribution proportion associated with the reduction mechanism corresponding to the ratio of the first flow rate (Q1d) to the main flow rate (Q1d+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 (Q1d+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 reservoir (Qr) corresponding to a difference between the auxiliary flow rate (Qc) and the sum of the second flow rate (Q1c) 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) to the auxiliary flow (Qc), of an auxiliary distribution proportion associated with the reduction mechanism corresponding to the ratio of the second flow (Q1c) to the auxiliary flow (Qc) and of an auxiliary distribution proportion associated with the other enclosures corresponding to the ratio of the fourth flow (Q2c) to the auxiliary flow (Qc).

A method for lubricating a turbomachine, the method comprising:

• a step of pumping lubricant contained in a reservoir of the turbomachine, and
• a turbomachine parts lubrication stage, the parts being housed in several turbomachine enclosures, 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.