Mechanical reducer for modular hybridization of a turbomachine.

Abstract

Mechanical gearbox (100) for modular hybridization of an aircraft turbomachine comprising an input pinion (112) of an input line (114), an output pinion (128) of an output line (129), and two intermediate gears (132) having a first set of teeth (130) meshing with the input pinion (112) and a second set of teeth (134) meshing with the output pinion (128), wherein the mechanical gearbox further comprises a hybridization pinion (140) of a hybridization line (144) meshing with the first set of teeth (130) of one of the two intermediate gears (132). Figure for the abstract: [Fig.2]

Description

Title of the invention: Mechanical reducer for modular hybridization of a turbomachine. Technical field of the invention

[0001] The invention relates to the field of mechanical gearboxes for aircraft turbomachinery. In particular, the invention relates to a mechanical gearbox enabling modular hybridization of a turbomachine. The invention further relates to a turboprop engine comprising such a mechanical gearbox. Prior art

[0002] Today, environmental objectives are leading to consideration of hybrid solutions for aircraft used in regional aviation, and therefore for the turboprop engines used in this type of aircraft. Typically, a turboprop engine comprises a turbomachine driving a propeller via a mechanical reduction gear. However, these hybrid solutions, based on current knowledge, result in bulky and heavy architectures, and the benefits of such a hybrid solution for the entire aircraft remain to be demonstrated. Indeed, current hybrid solutions do not initially meet the expectations of aircraft manufacturers, and consequently, do not meet the expectations of airlines wishing to adopt hybridization.

[0003] There is therefore a need to obtain an optional hybridization solution, which can offer several levels of hybridization, without penalizing the performance of the turboprop when it is not hybridized, so as to be able to adapt gradually to the expectations of aircraft manufacturers, and then of airlines when they convert to hybridization.

[0004] Document FR3073569A1 illustrates a hybrid solution for a turboprop engine where the electric machine is positioned between the propeller and the mechanical gearbox. Description of the invention

[0005] One object of the invention is to provide a mechanical reducer which makes it possible to achieve such an optional hybridization solution while remaining light and compact.

[0006] To this end, according to the invention, a mechanical reducer for modular hybridization of an aircraft turbomachine is provided, comprising an input pinion of an input line, an output pinion of an output line and two intermediate pinions having a first set of teeth meshed with the input pinion and a second set of teeth meshing with the output pinion, the mechanical reducer further comprising a hybridization pinion of a hybridization line meshing with the first set of teeth of one of the two intermediate pinions.

[0007] Advantageously, but optionally, the mechanical reducer according to the invention has at least one of the following technical characteristics: • the mechanical reducer includes another hybridization pinion from another hybridization line meshing with the first set of teeth of the other of the two intermediate pinions; • the mechanical reducer further includes a coupling means between the input line and the input pinion; • the coupling means is a freewheel, a dog clutch, a CURVIC® type coupling or a clutch; • the mechanical reducer further includes a coupling means between each hybridization line and each associated hybridization pinion; • the coupling means includes a controlled actuator arranged to open or close the coupling means; • the mechanical reducer includes means for measuring an axial force of the type force sensors allowing to estimate a helix torque and provided on one and the other of the two intermediate pinions; • The reducer includes a means for closing off an output of the hybridization line.

[0008] According to the invention, a turboprop engine for an aircraft is also provided, comprising a nacelle, a turbomachine, a propeller and a mechanical reducer between the turbomachine and the propeller, the mechanical reducer having at least one of the preceding technical characteristics.

[0009] Advantageously, but optionally, the turboprop according to the invention has at least one of the following technical characteristics: • the nacelle includes an electric machine whose rotor shaft forms the hybridization line; • the electric machine is an electric traction motor and / or a current generator; • the nacelle includes another electric machine, one of whose rotor shafts forms the other hybridization line; • the input line includes means for measuring turbine torque.

[0010] The invention also provides for a method of using a turboprop engine having at least one of the preceding technical characteristics, the method comprising the steps of: a. Determination of a mode of operation; b. If the operating mode is non-hybridized, absence of electrical machines on the hybridization lines or installation of one or two current generators on the hybridization lines; and, c. If the operating mode is hybrid, one or two electric machines should be installed on the hybridization lines.

[0011] Advantageously, but optionally, the method according to the invention has at least one of the following technical characteristics: • in hybridized operating mode, the hybridization lines having a coupling means, the process including a decoupling step of one of the hybridization lines to decouple the associated electrical machine; • the input line having a coupling means, the process includes a step of decoupling the input line for an electrical operating mode with the electrical machine(s) only; • in step c), the intermediate lines comprising means for measuring a turbine torque, the process includes a substep of limiting a torque of the electric machine as a function of a turbine torque measured on the associated intermediate line; • with two electrical machines in place, the process includes a sub-step of distributing a total set electrical power between the two electrical machines as a function of the turbine torque measured on each of the associated intermediate lines. Brief description of the figures

[0012] Other features and advantages of the invention will become apparent from the following description of an embodiment of the invention. See the accompanying drawings:

[0013] [Fig-1] is a partial three-dimensional view of a turboprop according to the invention;

[0014] [Fig.2] is a schematic view of a mechanical reducer according to the invention for the turboprop of the [Fig.1];

[0015] [Fig.3] is a front view of the fully hybridized turboprop of the [Fig.1];

[0016] [Fig.4] is a partial three-quarter rear three-dimensional view of the non-hybridized turboprop of the [Fig.l];

[0017] [Fig.5] is a partial three-dimensional three-quarter rear view of the hybridized [Fig.1] turboprop;

[0018] [Fig.6] is a partial three-quarter front three-dimensional view of the turboprop engine of [Fig.5]; and,

[0019] [Fig.7] is a schematic three-dimensional partial cross-sectional view of a mechanical reducer according to the invention.

[0020] For clarity, identical or similar elements are identified by identical reference signs throughout the figures. Detailed description of an implementation method

[0021] With reference to the figures, we will describe an embodiment of a mechanical reducer 100 according to the invention.

[0022] Figure 1 illustrates a turboprop 9 comprising a nacelle 2 for an aircraft. The nacelle 2 includes a turbomachine (T in Figure 2), a mechanical reduction gear 100 according to the invention, and a propeller 126. The propeller 126 is driven in a rotational motion by the turbomachine through the mechanical reduction gear 100 according to the invention. The turbomachine includes an air inlet 3 positioned below the mechanical reduction gear 100 according to the invention, behind the propeller 126.

[0023] The mechanical reducer 100 according to the invention is schematically illustrated in [Fig. 2] and [Fig. 7]. The mechanical reducer 100 according to the invention is, in this case, of the compound type. The mechanical reducer 100 according to the invention comprises an input pinion 112 of an input line 114 formed in part from an output shaft of the turbomachine T. This input pinion 112 meshes with a first set of teeth 130 of two intermediate pinions 132 which draw power. The intermediate gears 132 then drive an output gear 128 of an output line 129 via a second set of teeth 134 of the intermediate gears 132. By changing the number of teeth of the teeth 130, 134 of the gears 132, it is possible to obtain a speed reduction ratio between the input line 114 and the output line 129 connected to the propeller 126.

[0024] The mechanical reducer 100 according to the invention further comprises, here, two hybridization gears 140, each of the hybridization gears 140 being part of an associated hybridization line 144. Each hybridization gear 140 meshes with the first set of teeth 130 of the associated intermediate gear 132. In top view, as schematically shown in [Fig. 2], the intermediate gear 132 is positioned between the input gear 112 and the hybridization gear 140. Thus, the two hybridization gears 140 and their associated hybridization lines 144 extend on either side of the input line 114 and parallel to it. Again, by playing with the number of teeth on the 130, 134 teeth of the 132 pinions, it is possible to obtain a speed reduction ratio between the hybridization line(s) 144 and the output line 129 connected to the propeller 126.For example, typically for high-speed electric machines (from 10,000 to 37,000 rpm), the hybridization gear(s) 140 are similar in size and number of teeth to the input gear 112. They are therefore small in size, thus reducing the mass penalty compared to a traditional mechanical reducer.

[0025] Furthermore, between the hybridization line 144 and the hybridization pinion, a clutch means 141 is provided, such as a disc clutch, a dog clutch, a freewheel, or a CURVIC® type coupling, or any other suitable device for achieving coupling or decoupling, depending on the conditions, between the hybridization line 144 and the associated hybridization pinion 140. In addition, the clutch means 141 includes a actuator 143 which can preferably be controlled in order to achieve either a coupling or a decoupling between the hybridization gears 140 and associated hybridization line 144.

[0026] Within the turboprop 9, each hybridization line 144 corresponds to a shaft of an electric machine MEL. The electric machine MEL is a traction electric motor that supplies power to the propeller 126 via the mechanical reduction gear 100 according to the invention. In an alternative embodiment, the electric machine MEL is a current generator that draws power from the turbomachine T to supply current to an electrical system of the turboprop 9 or of the aircraft on which the turboprop 9 is installed, or to recharge one or more batteries equipping the aircraft. In another embodiment, the electric machine MEL can operate either as a traction electric motor or as a current generator.The clutch means 141 allows the electric machine MEL to be isolated from the rest of the traction chain, in particular from the mechanical reducer 100 according to the invention if necessary: ​​in the event of a failure of the electric machine MEL for example, or of non-use of the latter during certain phases of operation of the turboprop 9.

[0027] It should be noted that the presence of one or two MEL electric machines is optional. Thus, it is possible to modulate the hybridization of the turboprop 9 without having to alter the architecture of said turboprop 9. Thus, with the use of the mechanical reducer 100 according to the invention, it is possible to have a non-hybridized turboprop 9, illustrated in [Fig. 4], or a hybridized turboprop 9 with one or two MEL electric machines, illustrated in Figures 5 and 6. Thus, the use of the mechanical reducer 100 according to the invention is modular with regard to hybridization without having to modify, between the hybridization configurations (from zero to two MEL electric machines), the arrangement of gears of the mechanical reducer 100 according to the invention.On the other hand, the two intermediate gears 132 generate a significant center distance, allowing the MEL electric machines to bypass the torque tube coupling of the turbomachine (T) with the mechanical reduction gear 100 according to the invention, as well as with the air intake 3. Furthermore, the MEL electric machines are easily accessible, as they are located under an engine cradle and do not impact said cradle within the nacelle 2 without modifying its dimensions. This facilitates adaptation to a hypothetical and immature market for hybridized turboprop engines. Moreover, the ability to carry up to two MEL electric machines allows for smaller dimensions and better integration within the nacelle 2, thus avoiding large protrusions (impacting the airframe torque) when a single MEL electric machine is considered, and allows for better adaptation to the power requirements of aircraft manufacturers.Furthermore, each hybridization line 144 passes through an associated output of the mechanical reducer 100 according to the invention. In the case of... where no electrical machine is placed on the hybridization line 144, the mechanical reducer 100 includes a means for closing the output. Thus, it is possible to modulate the hybridization of the turboprop 9 without having to modify the mechanical reducer 100 according to the invention.

[0028] On the other hand, the input pinion 112 is connected to the input line 114 by a coupling means 110. The coupling means 110 prevents the input line 114 from being driven when the MEL electric machine(s) operate in traction electric motor mode to drive, via the mechanical reducer 100 according to the invention, the propeller 126 in 100% electric mode. In one embodiment, the coupling means is a freewheel. In another embodiment, the coupling means 110 is a clutch or any other suitable coupling device.

[0029] In order to carry out a propeller torque monitoring, in the context, for example, of implementing a HUMS function (Anglo-Saxon acronym for "Health and Usage Monitoring System" or Equipment Condition and Usage Monitoring System) at the turboprop 9 level, the mechanical reducer 100 according to the invention is provided, on each of the two intermediate gears 132, with means 5 for measuring a propeller torque resulting from a sum of the two torques measured at the levels of the two intermediate gears 132.

[0030] Another role of the measuring means 5 is to enable monitoring and torque limitation of the MEL electric machine(s) to avoid oversizing a low-speed stage (at the output pinion 128 and the second sets of teeth 134), and to limit a mass penalty of the mechanical gearbox 100 according to the invention when the turboprop 9 is non-hybridized. It is thus possible to limit the torque of each of the MEL electric machines potentially present within the turboprop 9 so as not to exceed the sizing margins of a second reduction stage (particularly at the output pinion 128 and the second sets of teeth 134), due to variability related to maneuvering loads (limiting mass to limit a penalty related to an optionally hybridized configuration, i.e., ensuring that in thermal-only mode, the second stage is not significantly heavier).

[0031] These measuring means 5 also come into play during joint operation between the turbomachine T and the MEL electric machine(s) (within the previously mentioned torque limitation) and closely approximate a power setpoint under switching load and significant casing deformation, when the MEL electric machine(s) supplement the torque supplied by the turbomachine T. In the case of two MEL electric machines, an identical setpoint is sent to each MEL electric machine. Under switching load, a total power (mainly thermal) can preferentially pass to one side of the gearbox. mechanical 100 according to the invention, either by one of the two intermediate gears 132. A power distribution between the two electrical machines MEL is adjusted so as to minimize a difference in total power (thermal + electrical) between the two sides of the last stage of the mechanical reducer 100 according to the invention (at the output gear 128). The sum of the electrical powers is, in this case, ideally in accordance with the setpoint. The measuring means 5 allow control of a distribution of a total setpoint electrical power between the two electrical machines (MEL), if both are present in the turboprop 9, while respecting the torque limitations at the level of each of the intermediate lines 132.

[0032] Similarly, means for measuring a turbine torque 6 are provided on the input line 114. These means for measuring a turbine torque 6 allow protection of the turbomachine T and the reducer 100 according to solutions known per se.

[0033] In use, a method for operating the turboprop 9 comprising a mechanical reduction gear 100 according to the invention includes a first step of determining an operating mode: either a non-hybridized operating mode or a hybridized operating mode. If the operating mode is non-hybridized, the method provides for the absence of MEL electrical machines on the hybridization lines 144 or the installation of one or two current generators on the hybridization lines. Thus, the turboprop 9 operates in pure thermal mode without having to modify the mechanical reduction gear 100 according to the invention. Alternatively, the presence of current generators on the hybridization lines 144 allows the electrical circuit of the aircraft comprising the turboprop 9 to be powered.Conversely, if the operating mode is hybridized, the method of use provides for the installation of one or two reversible electric machines (MELs) on the hybridization lines 144. In this hybridized operating mode, the method of use allows for a variable level of hybridization by enabling the mechanical reducer 100 according to the invention to be coupled with zero, one, or two electric machines (MELs). To achieve this, the method of use includes a decoupling step of one of the hybridization lines 144 to disconnect the associated electric machine by implementing the associated clutch means 141. Furthermore, to allow for purely electric operation, the method of use includes a decoupling step of the input line 110 via the coupling means 110.

[0034] Naturally, the invention is described above by way of example. It is understood that a person skilled in the art is able to carry out different embodiments of the invention without departing from the scope of the invention.

[0035] It is emphasized that all features, as they are apparent to a person skilled in the art from the present description, drawings and attached claims, even if in practice they have only been described in relation to other specific features, both individually and in any combinations, may be combined with other features or groups of features disclosed herein, provided that this has not been expressly excluded or that technical circumstances make such combinations impossible or meaningless.

Claims

Demands

1. Mechanical reducer (100) for modular hybridization of an aircraft turbomachine comprising an input pinion (112) of an input line (114), an output pinion (128) of an output line (129) and two intermediate pinions (132) having a first set of teeth (130) meshed with the input pinion (112) and a second set of teeth (134) meshing with the output pinion (128), wherein the mechanical reducer further comprises a hybridization pinion (140) of a hybridization line (144) meshing with the first set of teeth (130) of one of the two intermediate pinions (132).

2. Mechanical reducer according to claim 1, wherein the mechanical reducer comprises another hybridization pinion (140) of another hybridization line (144) meshing with the first set of teeth (130) of the other of the two intermediate pinions (132).

3. Mechanical reducer according to any one of claims 1 to 2, wherein the mechanical reducer further comprises a coupling means (110) between the input line (114) and the input pinion (112).

4. Mechanical reducer according to claim 3, wherein the coupling means is a freewheel, a dog clutch, a CURVIC® type coupling or a clutch.

5. Mechanical reducer according to any one of claims 1 to 4, wherein the mechanical reducer further comprises a coupling means (141) between each hybridization line (144) and each associated hybridization pinion (140).

6. Mechanical reducer according to claim 5, wherein the coupling means comprises a piloted actuator (143) arranged to open or close the coupling means.

7. Mechanical reducer according to any one of claims 1 to 6, wherein the mechanical reducer includes means for measuring an axial force of the type force sensors (5) allowing estimation of a helix torque and provided on either of the two intermediate pinions (132).

8. Reducer according to any one of claims 1 to 7, wherein the reducer comprises a means for closing an outlet of the hybridization line (144).

9. Turboprop (9) for aircraft comprising a nacelle (2), a turbomachine (T), a propeller (126) and a mechanical reducer (100) between the turbomachine and the propeller, wherein the mechanical reducer is according to any one of claims 1 to 8.

10. Turboprop according to claim 9, wherein the nacelle comprises an electric machine (MEL) of which a rotor shaft forms the hybridization line (144).

11. Turboprop according to claim 10, wherein the electric machine is an electric traction motor and / or a current generator.

12. Turboprop according to any one of claims 9 to 11, wherein the nacelle includes another electric machine of which a rotor shaft forms the other hybridization line.

13. Turboprop according to any one of claims 9 to 12, wherein the inlet line (114) comprises means for measuring a turbine torque (6).

14. A method of using a turboprop (9) according to any one of claims 9 to 13, wherein the method comprises steps of: a. Determining a mode of operation; b. If the mode of operation is non-hybridized, absence of electrical machines on the hybridization lines (144) or installation of one or two current generators on the hybridization lines; and, c. If the mode of operation is hybridized, installation of one or two electrical machines (MEL) on the hybridization lines (144).

15. A method according to claim 14, wherein, in hybridized operating mode, the hybridization lines comprising a coupling means, the method comprising a decoupling step of one of the hybridization lines to decouple the associated electrical machine.

16. A method according to any one of claims 14 to 15, wherein the input line (114) includes a coupling means (110), the method includes a step of decoupling the input line for an electrical operating mode with the electrical machine(s) only.

17. A method according to any one of claims 14 to 16, wherein in step c), the intermediate lines (132) comprising means for measuring a turbine torque, the method comprises a substep of limiting a torque of the electric machine (MEL) as a function of a turbine torque measured on the associated intermediate line (132).

18. A method according to claim 16, wherein, with two electrical machines in place, the method comprises a substep of distributing a total set electrical power between the two electrical machines as a function of the turbine torque measured on each of the associated intermediate lines.

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