Measuring a movement or a force in a speed reduction device of an aeronautical propulsion system

Abstract

An aeronautical propulsion system (1) comprising a stator (34), a drive shaft (30), a fan section (2) comprising a fan shaft (20) and a fan rotor (9), a speed reduction device (19) rotationally coupling the drive shaft (30) and the fan shaft (20), the reduction device (19) comprising a sun gear (19a), a ring gear (19b), a diameter of the ring gear being greater than a diameter of the sun gear, a planet carrier (19d), at least one planet gear (19c) rotatably mounted on the planet carrier (19d), and a support (32) fastened to the stator (34), the ring gear (19b) or the planet carrier (19d) being held non-rotatably with respect to the support (32), the propulsion system (1) comprising a measuring device (36) configured to measure a relative movement between the support (32) and the stator (34), or / and a force exerted by the support (32) on the stator (34), the support (32) comprising a body (33) and a projection (38) which projects from the body (33) radially with respect to an axis (X) of rotation of the sun gear (19a), the stator (34) comprising a base (35) and a stop (40) which projects from the base (35) radially, the stop (40) being arranged, circumferentially with respect to the axis (X) of rotation, facing the projection (38), the measuring device (36) comprising at least one sensor (42), the at least one sensor comprising a portion (42a) mounted on an element among the stop (40) and the projection (38), the propulsion system (1) comprising a measuring assembly (50a) comprising the projection (38), the stop (40) and the at least one sensor (42), the measuring assembly (50a) comprising a second stop (46) of the stator (34), the second stop (46) projecting from the base (35) radially, the second stop (46) being arranged circumferentially facing the projection (38), the projection (38) being located circumferentially between the first stop (40) and the second stop (46).

Description

[0001] Measurement of a displacement or force in a speed reduction device of an aeronautical propulsion system.

[0002] DOMAIN

[0003] This application generally relates to the field of propulsion systems, and more particularly to aeronautical propulsion systems comprising a ducted or unducted fan and having a high, or even very high, bypass ratio.

[0004] STATE OF THE ART

[0005] A propulsion system generally comprises, from upstream to downstream in the direction of gas flow, a fan section, a compressor section which may include a low-pressure compressor and a high-pressure compressor, a combustion chamber and a turbine section which may include in particular a high-pressure turbine and a low-pressure turbine. The high-pressure compressor is rotated by the high-pressure turbine via a high-pressure shaft. The fan and, where appropriate, the low-pressure compressor are rotated by the low-pressure turbine via a low-pressure shaft.

[0006] Technological research efforts have already led to very significant improvements in the environmental performance of aircraft. The Applicant takes into consideration the impact factors in all phases of design and development to obtain less energy-intensive, more environmentally friendly aeronautical components and products whose integration and use in civil aviation have moderate environmental consequences with the aim of improving the energy efficiency of aircraft.

[0007] Thus, in order to improve the propulsive efficiency of the propulsion system and to reduce its specific consumption as well as the noise emitted by the fan section, propulsion systems have been proposed having a high BPR (bypass ratio in English, corresponding to the ratio between the flow rate of the secondary air flow and the flow rate of the primary air flow). To achieve such bypass ratios, the fan section can be decoupled from the low-pressure turbine, thus making it possible to independently optimize their respective rotational speeds. Generally, the decoupling is achieved using a reduction device placed between the upstream end of the low-pressure shaft and a rotor of the fan section. The rotor of the fan section is then driven by the low-pressure shaft via the reduction device at a rotational speed lower than that of the low-pressure shaft.

[0008] When the propulsion system is a variable-pitch turboprop or a variable-pitch turbomachine, thrust control is generally achieved by measuring the torque on the power transmission chain from the turbine section to the fan (typically referred to as the propeller for an unducted fan or sometimes as the "fan" for a ducted fan). The transmitted torque, as well as the service life of the reduction device, is highly dependent on the control of the pitch angle. Furthermore, monitoring the mechanical behavior of the reduction device makes it possible to assess and monitor the viability of the reduction device throughout its life, and to anticipate its maintenance.

[0009] Various solutions exist for measuring torque at the input or output of a rotating machine. A distinction is made between rotating measurements (typically by measuring the phase shift or deformation of a rotating shaft deformed under the action of the torque) and static measurements (typically by measuring the deformation of a part through which all or part of the torque passes using a strain gauge).

[0010] More generally, there are various solutions for measuring various physical quantities related to the control and mechanical behavior of the engine. However, these solutions generally have a certain amount of space, they are not always versatile and the reliability or precision of the measurements they provide remains improvable. There is therefore a need to provide a device for measuring mechanical behavior within a propulsion system that is reliable, precise, compact and simple.

[0011] EXPOSED

[0012] An aim of the present disclosure is to propose a device for measuring mechanical behavior within a propulsion system which is more reliable, more precise, less bulky and simpler than in the prior art.

[0013] The aim is achieved by means of an aeronautical propulsion system comprising: a stator, a drive shaft, a fan section comprising a fan shaft and a fan rotor, the fan rotor being configured to be driven in rotation by the fan shaft, a speed reduction device coupling in rotation the drive shaft and the fan shaft, so as to drive the fan shaft at a rotational speed lower than a rotational speed of the drive shaft, the reduction device comprising:

[0014] -- a sun gable,

[0015] -- a crown, a diameter of the crown being greater than a diameter of the sun pinion,

[0016] -- a satellite carrier,

[0017] -- at least one satellite pinion mounted in rotation on the satellite carrier, and

[0018] -- a support fixed to the stator, the crown or the planet carrier being kept fixed in rotation relative to the support, the propulsion system comprising a measuring device configured to measure: -- a relative displacement between the support and the stator, and / or -- a force exerted by the support on the stator.

[0019] Such a system is optionally supplemented by the following different characteristics taken alone or in combination:

[0020] - the measuring device is configured to measure the relative displacement and / or force as a function of time;

[0021] - relative displacement and force are measured in a circumferential direction relative to an axis of rotation of the sun gear;

[0022] - the support comprises a body and a relief which projects radially from the body relative to an axis of rotation of the sun gear, the stator comprising a base and a stop which projects radially from the base, the stop being arranged, circumferentially relative to the axis of rotation, opposite the relief, the measuring device comprising at least one sensor, the at least one sensor comprising a part mounted on one of the stop and the relief, the propulsion system comprising a measuring assembly comprising the relief, the stop and the at least one sensor;

[0023] - the part of the at least one sensor is a first part, the at least one sensor comprising a second part mounted on the other element among the stopper and the relief;

[0024] - the measuring assembly comprises a second stopper of the stator, the second stopper projecting radially from the base, the second stopper being arranged circumferentially opposite the relief, the relief being situated circumferentially between the first stopper and the second stopper;

[0025] - the measuring assembly comprises two sensors located circumferentially on either side of the relief, each of the sensors cooperating respectively with a single stopper among the first stopper and the second stopper; - the measuring assembly comprises a sensor configured to measure the relative displacement and a sensor configured to measure the force;

[0026] - the measuring assembly is a first measuring assembly, of a plurality of measuring assemblies included in the system and regularly distributed circumferentially, for example the system comprising two assemblies which are diametrically opposed to each other; and

[0027] - the measuring device comprises at least one sensor chosen from: o a proximity sensor, such as for example a magnetic proximity meter, or an inductive proximity meter or a capacitive proximity meter, o a piezoelectric sensor, o an ultrasonic sensor, o an optical sensor, o an LVDT type sensor, o an RVDT type sensor, and o a hydraulic cylinder sensor.

[0028] This disclosure also relates to an aircraft comprising a propulsion system as just described.

[0029] DESCRIPTION OF FIGURES

[0030] Other characteristics will emerge from the following description, which is purely illustrative and non-limiting, and must be read in conjunction with the appended drawings in which: Figure 1 is a schematic, partial and sectional view of an example of a propulsion system according to a first embodiment, in which the fan section is ducted; Figure 2 is a schematic, partial and sectional view of an example of a propulsion system according to a second embodiment, in which the fan section is not ducted; Figure 3 is a schematic sectional view of an example of a reduction device according to a first variant; Figure 4 is a schematic sectional view of an example of a reduction device according to a second variant; Figure 5 is a schematic sectional view of a first embodiment of details associated with the reduction device;Figures 6 to 12 are schematic representations of the details of different embodiments associated with the reduction device; and Figure 13 is an example of an aircraft which may comprise at least one propulsion system according to the first or second embodiment;

[0031] DETAILED DESCRIPTION

[0032] In relation to Figures 1 and 2, a propulsion system 1 has a main direction extending along a longitudinal axis X and comprises, from upstream to downstream in the direction of flow of the gases in the propulsion system 1 when it is in operation, a fan section 2 and a primary body 3, often called a "gas generator", comprising a compressor section 4, 5, a combustion chamber 6 and a turbine section 7, 8.

[0033] The propulsion system 1 is here an aeronautical propulsion system 1 configured to be fixed on an aircraft 100 via a pylon (or mast), as illustrated in figure 13.

[0034] The compressor section 4, 5 comprises a succession of stages each comprising a moving blade wheel (rotor) 4a, 5a rotating in front of a fixed blade wheel (stator) 4b, 5b. The turbine section 7, 8 also comprises a succession of stages each comprising a fixed blade wheel (stator) 7b, 8b behind which a moving blade wheel (rotor) 7a, 8a rotates.

[0035] In the present application, the axial direction corresponds to the direction of the longitudinal axis X, in correspondence with the rotation of the shafts of the gas generator, and a radial direction is a direction perpendicular to this axis X and passing through it. Furthermore, the circumferential (or lateral, or even tangential) direction corresponds to a direction perpendicular to the longitudinal axis X and not passing through it. Unless otherwise specified, internal (respectively, interior) and external (respectively, exterior), respectively, are used in reference to a radial direction so that the internal part or face of an element is closer to the axis X than the external part or face of the same element.

[0036] In operation, an air flow F entering the propulsion system 1 is divided between a primary air flow F1 and a secondary air flow F2, which circulate from upstream to downstream in the propulsion system 1.

[0037] The secondary airflow F2 (also called "bypass airflow") flows around the primary body 3. The secondary airflow F2 allows the periphery of the primary body 3 to be cooled and is used to generate the majority of the thrust provided by the propulsion system 1.

[0038] The primary air flow F1 flows in a primary vein inside the primary body 3, passing successively through the compressor section 4, 5, the combustion chamber 6 where it is mixed with fuel to serve as an oxidant, and the turbine section 7, 8. The passage of the primary air flow F1 through the turbine section 7, 8 receiving energy from the combustion chamber 6 causes rotation of the rotor of the turbine section 7, 8, which in turn drives rotation of the rotor of the compressor section 4, 5 as well as a rotor part 9 of the fan section 2.

[0039] In a twin-body propulsion system 1, the compressor section 4, 5 may comprise a low-pressure compressor 4 and a high-pressure compressor 5. The turbine section 7, 8 may comprise a high-pressure turbine 7 and a low-pressure turbine 8. The rotor of the high-pressure compressor 5 is rotated by the rotor of the high-pressure turbine 7 via a high-pressure shaft 10. The rotor of the low-pressure compressor 4 and the rotor portion 9 of the fan section 2 are rotated by the rotor of the low-pressure turbine 8 via a low-pressure shaft 11. Thus, the primary body 3 comprises a high-pressure body comprising the high-pressure compressor 5, the high-pressure turbine 7 and the high-pressure shaft 10, and a low-pressure body comprising the fan section 2, the low-pressure compressor 4, the low-pressure turbine 8 and the low-pressure shaft 11.The rotational speed of the high-pressure spool is greater than the rotational speed of the low-pressure spool. In a triple-spool propulsion system 1, the turbine section 7, 8 further comprises an intermediate turbine, positioned between the high-pressure turbine 7 and the low-pressure turbine 8 and configured to drive the rotor of the low-pressure compressor 4 via an intermediate shaft. The fan rotor 9 and the rotor of the high-pressure compressor 5 remain driven by the low-pressure shaft 11 and the high-pressure shaft 10, respectively. The low-pressure shaft 11 is generally housed, over a section of its length, in the high-pressure shaft 10 and is coaxial with the high-pressure shaft 10. The low-pressure shaft 11 and the high-pressure shaft 10 may be co-rotating, i.e., driven in the same direction around the longitudinal axis X.Alternatively, the low-pressure shaft 11 and the high-pressure shaft are counter-rotating, i.e. driven in opposite directions around the longitudinal axis X. Where appropriate, the intermediate shaft is housed between the high-pressure shaft 10 and the low-pressure shaft 11. The intermediate shaft and the low-pressure shaft 11 may be co-rotating or counter-rotating.

[0040] The fan section 2 comprises at least the fan rotor 9 adapted to be rotated relative to a stator portion of the propulsion system 1 by the turbine section 7, 8. Each fan rotor 9 comprises a hub 13 and blades 14 extending radially from the hub 13. The blades 14 of each rotor 9 may be fixed relative to the hub 13 or have a variable pitch. In this case, the root of the blades 14 of each rotor 9 is pivotally mounted along a pitch axis and is connected to a pitch change mechanism 15 mounted in the propulsion system 1, the pitch being adjusted according to the flight phases by the pitch change mechanism 15. The pitch change mechanism 15 is illustrated in broken lines in Figure 1 to show that this feature is optional.

[0041] The fan section 2 may further comprise a fan stator 16, or rectifier, which comprises blades 17 mounted on a hub of the fan stator 16 and have the function of straightening the secondary air flow F2 which flows out of the fan rotor 9. The blades 17 of the fan stator 16 may be fixed relative to the hub or have a variable pitch. In a manner similar to the rotor blades 14, the root of the stator blades 17 is pivotally mounted along a pitch axis X and is connected to a pitch change mechanism 15a, which is generally separate from that of the fan rotor 9, the pitch being adjusted according to the flight phases by the pitch change mechanism.

[0042] The diameter D of the fan rotor can then be between 80 inches (203.2 cm) and 185 inches (469.9 cm) inclusive. When the fan rotor 9 is shrouded, the diameter D is for example between 85 inches (215.9 cm) and 120 inches (304.8 cm) inclusive, for example of the order of 90 inches (228.6 cm), which allows the propulsion system 1 to be integrated in a conventional manner, in particular under the wing of an aircraft. When the fan rotor 9 is unshrouded, the diameter D is for example greater than or equal to 100 inches (254 cm), for example between 120 inches (304.8 cm) and 156 inches (396.2 cm). The diameter of the fan rotor 9 is measured here in a plane normal to the axis X of rotation at an intersection between a tip 21 and a leading edge 22 of the blades 14 of the fan rotor 9, and is expressed in meters. Note that since Figures 1 and 2 are partial views, the diameter D is only partially visible.The fan rotor 9 further comprises at least 12 blades 14 and at most 24 blades 14, for example at least 16 blades 14 and at most 22 blades 14. The number of blades 16 in the fan stator 17 depends on the acoustic criteria defined for the propulsion system 1 and is at least equal to the number of blades 14.

[0043] In order to improve the propulsive efficiency of the propulsion system 1 and to reduce its specific consumption as well as the noise emitted by the fan section 2, the propulsion system 1 has a high bypass ratio. By high bypass ratio, we mean here a bypass ratio greater than or equal to 10, for example between 10 and 80 inclusive. To calculate the bypass ratio, the mass flow rate of the secondary air flow F2 and the mass flow rate of the primary air flow F1 are measured when the propulsion system 1 is stationary, uninstalled, in takeoff mode in a standard atmosphere (as defined by the International Civil Aviation Organization (ICAO) manual, Doc 7488 / 3, 3 eedition) and at sea level. It will be noted that, in the present application, the parameters (pressure, flow rate, thrust, speed, etc.) are systematically determined under these conditions. By "not installed" it will be understood here that the measurements are carried out when the propulsion system 1 is in a test bench (and not installed on an aircraft 100), the measurements then being simpler to carry out. The distances (length, radius, diameter, etc.) are, on the other hand, measured at ambient temperature (approximately 20° C) when the propulsion system 1 is cold, that is to say when the propulsion system 1 has been stopped for a sufficient period for the parts of the propulsion system to be at ambient temperature, it being understood that these dimensions vary little compared to the conditions in which the propulsion system 1 is in take-off mode.

[0044] The fan rotor 9 is decoupled from the low-pressure shaft 11 using a reduction device 19, placed between an upstream end of the low-pressure shaft 11 and the fan rotor 9, in order to optimize their respective rotation speed. In this case, which in reality corresponds to an indirect coupling provided by the reduction device, the propulsion system 1 further comprises an additional shaft, called the fan shaft 20. The low-pressure shaft 11 connects the low-pressure turbine 8 to an inlet of the reduction device 19, while the fan shaft 20 connects the outlet of the reduction device 19 to the fan rotor 9. The fan rotor 9 is therefore driven by the low-pressure shaft 11 via the reduction device 19 and the fan shaft 20 at a rotation speed lower than the rotation speed of the low-pressure turbine 8.

[0045] This "decoupling" via the reduction device makes it possible to reduce the rotational speed and the pressure ratio of the fan rotor 9 and to increase the power extracted by the low-pressure turbine 8. Indeed, the overall efficiency of the propulsion systems is conditioned to the first order by the propulsive efficiency, which is favorably influenced by a minimization of the variation in kinetic energy of the air when passing through the propulsion system 1. In a propulsion system 1 with a high bypass ratio, the majority of the flow generating the propulsive force is constituted by the secondary air flow F2 of the propulsion system 1, the kinetic energy of the secondary air flow F2 being mainly affected by the compression that the secondary air flow F2 undergoes when passing through the fan section 2.The propulsive efficiency and the pressure ratio of the fan section 2 are therefore linked: the lower the pressure ratio of the fan section 2, the better the propulsive efficiency. In order to optimize the propulsive efficiency of the propulsion system 1, the pressure ratio of the fan, which corresponds to the ratio between the average pressure at the outlet of the fan stator 17 (or, in the absence of a stator, of the fan rotor 9) and the average pressure at the inlet of the fan rotor 9, is less than or equal to 1.70, for example less than or equal to 1.50, for example between 1.05 and 1.45. The average pressures are measured here over the height of the blade 14 (from the surface which radially delimits the flow path at the inlet of the fan rotor 9 to the tip 21 of the fan blade 14).

[0046] The propulsion system 1 is configured to provide thrust between 18,000 Ibf (80,068 N) and 51,000 Ibf (222,411 N), for example between 20,000 Ibf (88,964 N) and 35,000 Ibf (155,688 N).

[0047] The fan section 2 may be ducted or unducted. In the case of a ducted fan section 2, the fan section 2 comprises a fan casing 12 and the fan rotor 9 is housed in the fan casing 12.

[0048] A ducted fan section 2 comprises a fan rotor 9 extending upstream of a fan stator. The vanes of the fan stator are then generally called outlet vanes (“Outlet Guide Vane” or “OGV” in English) and have a fixed pitch relative to the hub of the fan stator. Furthermore, the bypass ratio of the propulsion system 1 is for example greater than or equal to 10, for example between 10 and 35 inclusive, for example between 10 and 18 inclusive. The peripheral speed at the tip 21 of the vanes of the fan rotor 9 may also be between 260 m / s and 400 m / s. The vanes 14 of the fan rotor 9 may be fixed or have a variable pitch. The fan pressure ratio may then be between 1.20 and 1.45.

[0049] In an unducted fan section 2, the fan section 2 (which may also be referred to as the propeller) is not surrounded by a fan casing. Since the fan section 2 is unducted, the blades 14 of the fan rotor 9 have a variable pitch. Propulsion systems comprising at least one unducted fan rotor 9 are known as “open rotor” or “unducted fan”. The propulsion system 1 may comprise two unducted and counter-rotating fan rotors 9. Such a propulsion system 1 is known by the acronym CROR for “Contra-Rotating Open Rotor” or UDF for “Unducted Double Fan”. The fan rotor(s) 9 may be placed at the rear of the primary body 3 so as to be of the pusher type or at the front of the primary body 3 so as to be of the tractor type.Alternatively, the propulsion system 1 may comprise a single unducted fan rotor 9 and an unducted fan stator 16 (straightener). Such a propulsion system 1 is known by the English acronym USF for “Unducted Single Fan”. In the case of a propulsion system 1 of the USF type, the blades 17 of the straightener 16 are fixed in rotation relative to the axis X of rotation of the upstream fan rotor 9 and consequently do not undergo centrifugal force. The blades 17 of the straightener 16 are also variable-pitch.

[0050] The removal of the fairing around the fan section 2 makes it possible to increase the bypass ratio very significantly without the propulsion system 1 being penalized by the mass of the casings or nacelles intended to surround the fan section 2. The bypass ratio of the propulsion system 1 comprising an unfaired fan section 2 is thus greater than or equal to 40, for example between 40 and 80 inclusive. The peripheral speed at the tip 21 of the blades 14 of the fan rotor(s) 9 may also be between 210 m / s and 260 m / s. The fan pressure ratio may then be between 1.05 and 1.20, for example.

[0051] In relation to Figures 3 and 4, the reduction device 19 may comprise a reduction device with an epicyclic gear train, for example of the “epicyclic” type or of the “planetary” type, single-stage or two-stage.

[0052] According to a first variant illustrated in Figure 3, the reduction device 19 may be of the planetary type (“star” in English) and comprise a sun gear 19a (input of the reduction device 19), centered on an axis X of rotation of the reduction device 19 (generally confused with the longitudinal axis X) and configured to be driven in rotation by a transmission shaft 30 (such as for example the low-pressure shaft), a ring gear 19b (output of the reduction device 19) coaxial with the sun gear 19a and configured to drive the fan shaft 20 in rotation about the axis X of rotation, and at least one satellite gear 19c between the sun gear 19a and the ring gear 19b, the satellite 19c being meshed internally with the sun gear 19a and externally with the ring gear 19b.When the reduction device 19 comprises several satellite pinions 19c, these are distributed circumferentially around the axis X of rotation between the sun pinion 19a and the crown 19b, each satellite 19c.

[0053] Each planet gear 19c is mounted to rotate freely about a direction parallel to the X axis or almost parallel to the X axis, on a planet carrier 19d. The planet carrier 19d is held fixed in rotation relative to a support 32. The support 32 is itself fixed to a stator 34 of the propulsion system 1. The stator 34 is for example a casing of the compressor section 4, 5.

[0054] According to a second variant illustrated in figure 4, the reduction device 19 can be of the epicyclic type (“planetary” in English), in which case the crown 19b is kept fixed in rotation relative to the support 32. The support 32 is itself fixed to the stator 34 of the propulsion system 1. The stator 34 is for example a casing of the compressor section 4, 5. The fan shaft 20 is driven in rotation by the planet carrier 19d which is therefore movable in rotation relative to the stator 34 of the propulsion system 1.

[0055] Regardless of the configuration of the reduction device 19, the support 32 may be an annular support, and the stator 34 may be an annular fixed casing, or an air inlet casing or an enclosure casing.

[0056] Whatever the configuration of the reduction device 19, the diameters of the crown 19b and the planet carrier 19d are greater than the diameter of the sun gear 19a, so that the rotational speed of the fan rotor 9 is lower than the rotational speed of the low pressure shaft 11. The reduction ratio - or reduction ratio - of the reduction device 19 is greater than or equal to 2.5 and less than or equal to 11. In the case of a propulsion system 1 comprising a shrouded fan rotor 9, the reduction ratio may be greater than or equal to 2.7 and less than or equal to 6.0, typically around 3.0. In the case of a propulsion system 1 comprising an unshrouded fan rotor, the reduction ratio may be between 9.0 and 11.0.

[0057] The dual-body propulsion system 1 may in particular comprise a two-stage high-pressure turbine 7, a high-pressure compressor 5 comprising at least eight stages and at most eleven stages, a low-pressure turbine 8 comprising at least three stages and at most five stages and a low-pressure compressor 4 comprising at least two stages and at most four stages.

[0058] The redline speed of the low pressure shaft 11, which corresponds to the absolute maximum speed likely to be encountered by the low pressure shaft 11 during the entire flight (according to the European certification regulation EASA CS-E 740 (or according to the American certification regulation 14-CFR Part 33.87)), is between 8500 rpm and 12000 rpm, for example between 9000 rpm and 11000 rpm. The redline speed corresponds to the maximum rotation speed when the propulsion system is healthy (and potentially at the end of its life). It is therefore likely to be reached by the low pressure shaft 11 in flight conditions. This redline speed is part of the data declared in the engine certification (type certification data sheet).Indeed, this rotation speed is usually used as a reference speed for the dimensioning of propulsion systems 1 and in certain certification tests (such as blade loss or rotor integrity tests).

[0059] Measuring device The propulsion system 1 comprises a measuring device 36 configured to measure a relative displacement between the support 32 and the stator 34, or / and a force exerted by the support 32 on the stator 34.

[0060] Such a measuring device makes it possible to monitor the mechanical behavior of the reduction device.

[0061] In operation, the support 32 is a part which takes up at least part of the forces applied to the reduction device 19 so that the support 34 keeps the planet carrier 19d fixed in rotation when the reduction device 19 is of the planetary type or the crown wheel 19b when the reduction device 19 is of the epicyclic type.

[0062] Under the action of part of the forces applied to the reduction device 19, the support 32 can transmit part of these forces to the stator 34.

[0063] The support 32 may be more flexible than the stator 34, particularly in torsion around the X axis. In this way, when the support 32 is subjected to forces, the support 32 may deform relative to the stator 34, the stator 34 then being considered as a fixed reference. This flexible aspect of the support makes it possible, in particular, to compensate for any misalignments (relative to the axis of the engine) between the drive shaft 30 and the fan shaft 20. This flexible aspect also makes it possible to filter vibrations.

[0064] Monitoring the forces exerted by the support 32 on the stator 34 and / or the relative movements between the support 32 and the stator 34 provides more general information on the forces applied to the reduction device 19. This monitoring makes it possible, for example, to monitor the movements or local vibrations of the reduction device 19, and more generally to monitor the state of health of the reduction device 19.

[0065] These measurements, alone or in combination, make it possible to estimate the torque (for example by charts) which applies to the support 32, and therefore the torque transmitted via the reduction device 19 from the low pressure shaft to the fan shaft. These measurements make it possible to estimate a mechanical behavior of the support and / or of the speed reduction device 19.

[0066] The measurement is carried out in relation to the support 32 which is one of the parts of the speed reducer 19 most subject to vibrations, forces, displacements and torques during operation of the reduction device 19. The measurement produced is all the richer in information, for example it is possible to estimate the meshing frequency of the teeth which is a key parameter for monitoring the state of health of the reducer. The measuring device 36 also makes it possible to detect a possible failure of the support 32, in particular by detecting a loss of one or more sensors, or when the measurement of the displacement indicates contact between the support 32 and the stator 34. The identification of contact is a normative obligation with regard to dormant failures (i.e. failures which are not immediately detectable or detected) of the support.

[0067] The measurement of the displacement and / or force is carried out in a fixed reference between the stator 34 and the support 32, the support 32 moving very little in comparison with the parts set in motion in the speed reducer 19. The measurement therefore does not require the use of a rotating transfer, with the problems of play associated with it, or the problem of transmitting the acquisition signals for example by telemetry.

[0068] The stator 34 may comprise an orifice 44 as illustrated in FIG. 6, which makes it possible to pass a physical connection 42c connecting the sensor 42 to a memory or to a computer so as to transmit the measurement signal from the sensor 42 to this memory or this computer.

[0069] Such a measuring device 36 is simple to implement, because the parts of the measuring device 36 involved in the measurement are fixed or almost fixed, and one simply measures a relative deformation and / or a force (force, stress, pressure or other) exerted by the support 32 on the stator 34. In addition, such a measuring device can be arranged between the support 32 and the stator 34, that is to say in an area of ​​the propulsion system which is generally not very cluttered. The measuring device 36 as described allows a saving of space.

[0070] The measuring device 36 may be configured to measure the relative displacement and / or force as a function of time, i.e. the measuring device 36 may enable monitoring of the relative displacement and / or force over time by providing a series of time measurements of the relative displacement and / or force.

[0071] Such a measuring device 36 can allow a frequency analysis of the measured values, allowing a more detailed knowledge of the mechanical behavior, and in particular the vibration behavior, of the support 32. Such an analysis makes it possible to dispense with any additional frequency monitoring devices, and therefore indirectly allows a saving in space and mass. It should be noted in this regard that a device for measuring torque normally requires the clearance of a significant axial length, which may lead to having to lengthen the motor.

[0072] For example, the relative displacement and / or the force are measured in a circumferential direction relative to an axis X of rotation of the sun gear 19a. In operation, the support 32 is in particular subjected to torques centered on the axis X of rotation of the sun gear. This axis X is the main axis of rotation of the speed reduction device and it generally corresponds to the axis of rotation of the transmission shaft 30 and to the axis of rotation of the fan shaft 20. When the relative displacement and / or the force are measured in the circumferential direction around the axis X, the measuring device 36 provides information in particular on the torques involved around the main axis of rotation of the speed reduction device.

[0073] A circumferential measurement of the forces and / or the displacement makes it possible to reliably measure a torque. The torque range that the measuring device 36 can measure extends, for example, from 0 to 500,000 Nm. This torque monitoring can be adapted to configurations where the fan (propeller or fan) has variable-pitch blades. Controlling the pitch can have a significant influence on the torque, and therefore the service life of the reducer.

[0074] In one embodiment of the measuring device 36, the support 32 comprises a body 33 and a relief 38 which projects from the body 33 radially relative to the axis X and the stator 34 comprises a base 35 and a stopper 40 which projects from the base 35 radially relative to the axis X.

[0075] With reference to Figures 3, 4 and 5, the body 33 of the support 32 may be an annular part which surrounds the axis X and the base 35 of the stator 34 may be an annular casing which surrounds the body 33 of the support 32. The body 33 of the support 32 and the base 35 of the stator 34 may be opposite each other.

[0076] The diameter of the body 33 or of the stator 34 may in particular be between 200 mm and 3000 mm.

[0077] The relief 38 is for example an outgrowth or projection of the body 33 which extends from the body 33 of the support 32 radially outwards, that is to say which extends from the body 33 away from the axis X.

[0078] The stopper 40 is for example an outgrowth or projection of the base 35 which extends from the base 35 of the stator 34 radially inwards, that is to say which extends from the base 35 approaching the axis X.

[0079] The stopper 40 is arranged, circumferentially with respect to the axis X of rotation, opposite the relief 38.

[0080] The measuring device 36 comprises at least one sensor 42, the at least one sensor comprising a first portion 42a mounted on one of the stopper 40 or the relief 38. Optionally, the at least one sensor 42 comprises a second portion 42b mounted on the other of the stopper 40 and the relief 38, respectively.

[0081] A measuring assembly 50a can be defined included in the propulsion system 1 which in this case includes the relief 38, the stopper 40 and at least one sensor 42.

[0082] The sensor 42 can measure the relative displacement between the relief 38 and the stopper 40, or a force exerted by the relief 38 on the stopper 40.

[0083] This embodiment of the measuring device 36 can be produced in particular with a relief 38 and a stopper 40 which are respectively a shoulder of the support 32 and a shoulder of the stator 34, shoulders which can be provided to cooperate within a protection mechanism against a possible breakage of the support 32. This protection mechanism is known as a dog clutch or anti-rotation dog clutch. It can be provided in the propulsion system so that in the event of accidental breakage of the support 32, the latter is not driven in rotation by the planet carrier 19d or by the ring gear 19b. In the event of accidental breakage of the support 32, the relief 38 is driven with the support 32 in a circumferential direction. The relief 38 is found in abutment against the stopper 40, and by this blocking the support 32 is held in rotation by the stator 34.In this case, the measuring device 36 plays a role as a safety device to limit the deformations of the support 32 and / or block the movements of the support 32 in the event of rupture. This embodiment allows better integration of the monitoring device by reducing the size of the propulsion system 1.

[0084] The propulsion system can be configured so that in normal operation, the relief 38 is not in contact (i.e. remains distant) from the stopper 40. In this case, the measuring device 36 makes it possible to detect a possible failure of the support 32, when the sensor indicates contact of the relief 38 with the stopper 40. This indication can make it possible to fulfill a normative obligation with regard to dormant failures (i.e. failures which are not immediately detectable or detected) of the support.

[0085] Optionally, the measuring assembly 50a comprises a second stopper 46 of the stator 34. The second stopper 46 extends, like the first stopper 40, projecting from the base 35 radially. The second stopper 46 is arranged circumferentially opposite the relief 38, the relief 38 is situated circumferentially between the first stopper 40 and the second stopper 46. In this option, and as illustrated in FIG. 5, the relief 38 is framed in the circumferential direction by the two stops 40 and 46.

[0086] The second stopper 46 may be, in the same way as the first stopper 40, an outgrowth of the base 35 which extends from the base 35 of the stator 34 radially inwards, that is to say from the base 35 approaching the axis X.

[0087] In this option, the second stopper can also be part of a protection mechanism against possible accidental breakage of the support 32. In this case, whatever the direction of the rotational movement in which the relief 38 is driven, the latter ends up in abutment against the first stopper 40 or against the second stopper 46. The reliability of the propulsion system 1 is increased.

[0088] In this option, the measuring assembly 50a may comprise two sensors 42, 48 which are located circumferentially on either side of the relief 38. Each of the sensors 42, 48 cooperates respectively with a single stopper among the first stopper 40 and the second stopper 46.

[0089] The sensor 42 initially included in the measuring assembly 50a being fixed to the first stop 40, the sensor 42 cooperates with the first stop 40. The second sensor 48 cooperates with the second stop 46. For example, a second sensor 48 comprises a first part mounted on the relief 38 and a second part mounted on the second stop 46. In this case, the second sensor 48 provides a second measurement which can be used in combination with the first measurement provided by the first sensor 42.

[0090] If the two measurements relate to the same quantity, it is possible in particular to make an average of these two measurements and / or a differential measurement from these two measurements. The average value makes it possible to access averaged information, for example a first movement of the support 32 relative to the stator 34 whose effect is identical on each sensor. The value of the differential measurement makes it possible to access information of a different nature than the average value, for example a second movement of the support 32 relative to the stator 34 whose effect is different on each sensor. This makes it possible in particular to overcome the deformations and tolerances of each part, and therefore to improve the precision.

[0091] It is also possible to determine from these two measurements, the value of other quantities. For example, if each sensor provides a distance measurement respectively between one of the buffers 40, 46 and the relief 38, knowledge of these two measurements makes it possible to know the displacement of the relief 38 on the one hand in the circumferential direction and on the other hand in the radial direction. This is particularly the case when the faces of the relief are at an angle.

[0092] The two measurements can also relate to quantities of a different nature, for example the first sensor can measure a relative displacement and the other sensor can measure a force exerted by the support 32 on the stator 34.

[0093] According to this example, the monitoring of the mechanical behavior of the reduction device is more precise and more accurate, which makes it possible to refine the monitoring of the health of the reduction device and the anticipation of its maintenance and / or the measurement of the torque.

[0094] The measuring assembly 50a as presented so far may comprise a sensor configured to measure relative displacement and a sensor configured to measure force. With the presence of these two sensors, the measuring device 36 is configured to measure both relative displacement and force. The reliability and accuracy of the measurements produced by the measuring device 36 increase. In particular, this may extend the range of measurements that the measuring device 36 can perform, to more operating regimes. The overall increase in information permitted by the measuring device facilitates monitoring of the speed reduction device and its state of health.

[0095] The measuring assembly 50a as described up to now comprises the relief 38, the first stop 40, a first sensor 42, possibly a second stop 46 with a possible second sensor 48. This assembly may be a first assembly, the propulsion system 1 being able to comprise a plurality of measuring assemblies 50a, 50b, 50c, 50d. Each assembly occupies a limited angular sector, and it is possible to regularly distribute the different measuring assemblies around the X axis. Figure 5 illustrates the situation where the system comprises four measuring assemblies distributed in a cross around the X axis, each assembly comprising two stops and two sensors.

[0096] According to a particular example, the propulsion system 1 comprises two assemblies which are diametrically opposed to each other. More generally, the propulsion system may comprise a plurality of pairs of assemblies, the two assemblies of each of the pairs being diametrically opposed to each other. According to another example, the system comprises two assemblies, the two assemblies being arranged at 90° to each other.

[0097] Each measuring assembly can provide one or more measurements if the measuring assembly comprises several sensors. It should be noted that the different assemblies are identical or not, in particular each of the assemblies comprises on the one hand a stopper or two stops, and on the other hand a sensor, two sensors or more sensors. The propulsion system 1 may comprise a large number of reliefs 38, each forming part of a measuring assembly. This number may be less than or equal to 200.

[0098] The propulsion system 1 can produce a large number of measurements in parallel, for example a number less than or equal to 400 measurements or less than or equal to 200 measurements, or even less than or equal to 100 measurements. These different measurements can be provided in parallel and recorded for later processing. They can also be provided simultaneously, processed simultaneously or recorded for later processing. According to a variant, these measurements are processed in real time, for example to estimate the torque and control the pitch of the fan blades.

[0099] For example, increasing the number of measurement sets and therefore sensors makes it possible to enrich the measurements provided on the support and its behavior in relation to the stator. The reliability and precision of the measurements is improved.

[0100] It is possible for sensors of the same type and located at different radial positions around the X axis to determine averaged measurements and / or differential measurements as already mentioned above. This is particularly the case when the system comprises two sets which are diametrically opposed to each other, each set comprising at least one sensor of the same type.

[0101] Sensor Types

[0102] In relation to the measuring device, the measuring assembly or the measuring assemblies as they have been described up to now, these may comprise at least one sensor chosen from:

[0103] - a proximity sensor, such as a magnetic proximity sensor, an inductive proximity sensor or a capacitive proximity sensor,

[0104] - a piezoelectric sensor,

[0105] - an ultrasonic sensor,

[0106] - a surface acoustic wave (SAW) sensor, - an optical sensor,

[0107] - an LVDT type sensor,

[0108] - an RVDT type sensor, and

[0109] - a hydraulic cylinder sensor.

[0110] A proximity sensor or proximeter is a sensor configured to measure the distance separating the sensor from a studied object located nearby, that is to say at a distance less than the maximum distance measurable by the sensor.

[0111] There are different types of proximity sensors, such as magnetic proximity sensors, inductive proximity sensors and capacitive proximity sensors.

[0112] A magnetic proximity meter is a proximity meter whose measurement is based on a magnetic effect.

[0113] In an exemplary embodiment of a magnetic proximity meter, the sensor 42 illustrated in FIG. 7 comprises:

[0114] - a magnet 42b which is part of a second part of the sensor 42 fixed to the relief 38 of the support 32, and

[0115] - a coil 52 which surrounds an armature 54 made of “soft iron”, that is to say made of a magnetizable material; the coil 52 and the armature 54 are part of the first part 42a of the sensor 42 fixed to the stopper 40 of the stator 34.

[0116] The axis around which the coil 52 is wound corresponds here to a circumferential direction which is identical or almost identical to the axis of the magnet 42b.

[0117] The coil 52 is part of an electrical circuit through which an alternating current flows. This alternating current is supplied by a measuring system which is also part of the measuring device 36. The electrical circuit is an oscillating circuit whose resonant frequency can be determined. For this purpose, electrical wires 42c connect the coil 52 to the measuring system, the electrical wires being, for example, passed through an orifice 44 of the stator 34.

[0118] The alternating current flowing through the coil 52 creates a magnetic field and a magnetic interaction with the magnet 42b, or in other words a magnetic coupling with the magnet 42b.

[0119] The relative movement of the magnet 42b with respect to the coil 52 due in particular to the movement of the support 32 with respect to the stator 34, modifies the magnetic coupling between the coil 52 and the magnet 42b. The impedance of the coil 52 seen by the oscillating circuit is modified as is the resonant frequency of the oscillating circuit. The detection of the variation in the resonant frequency of the circuit is detected by the measuring system which can deduce therefrom the distance separating the coil 52 from the magnet 42b.

[0120] It should be noted that if the support 32 is made of a magnetizable material, such as steel, the magnet 42b may be surrounded by a paramagnetic material 50, such as titanium. Thus surrounded, the magnet 42b produces field lines which are not captured inside the magnetizable material of the support 32. This makes it possible to produce a magnetic coupling between the coil 52 and the magnet 42b which is strong enough to be able to be detected.

[0121] It should also be noted that the first part 42a of the sensor 42 and the stopper 40 can be fixed to the base 35 which is itself mounted removably relative to the stator 34. Fasteners 37 can be provided to fix to the stator 34 the base 35 carrying the sensor 42 and the stopper 40. Such a removable mounting makes it possible to simplify the assembly of the system as well as the disassembly and maintenance of the sensor.

[0122] Alternatively, the magnetic proximity meter may be mounted so that the magnet 42b is part of the first portion 42a of the sensor 42 attached to the stopper 40 of the stator 34, and the coil 52 and the armature 54 are part of the second portion 42b of the sensor 42 attached to the relief 38 of the support 32. TJ

[0123] The magnetic proximity meter as presented here makes it possible to measure the distance separating the relief 38 and the stopper 40 in the circumferential direction parallel to the axis of the winding of the coil 52 and the axis of the magnet 42b.

[0124] For example, a second coil 52 may be arranged on a second stopper which would be placed on the stator on the other side of the relief 38 relative to the first stopper 40. The relief 38 is thus framed in the circumferential direction by two stops each carrying a coil. Thus, two distance measurements of the relief relative to the first stopper and relative to the second stopper are available. This symmetrization of the distance measurement makes it possible to obtain a differential measurement and to overcome the deformations and tolerances of each part, and therefore to improve the overall accuracy of the measurement.

[0125] An inductive proximity meter is a proximity meter whose measurement is based on a magnetic induction effect.

[0126] In an exemplary embodiment of an inductive proximity meter, called a lateral proximity meter or circumferential proximity meter, the sensor 42 illustrated in FIG. 8 comprises:

[0127] - a magnet 56 which is part of the first part 42a of the sensor 42 fixed to the stopper 40 of the stator 34,

[0128] - a coil 52 which surrounds the magnet 56, the coil also forming part of the first part 42a of the sensor 42 fixed to the stopper 40 of the stator 34.

[0129] The magnet 56 and the coil have the same axis which is oriented in the circumferential direction.

[0130] In a second exemplary embodiment of an inductive proximity meter, called a radial inductive proximity meter, the sensor 42 illustrated in FIGS. 9 and 10 differs in that the magnet 56 and the coil 52 have the same axis which is oriented this time in a radial direction. This second example is notably implemented when the measuring assembly comprises two stops 40 and 46 placed on either side of the relief 38. The two stops make it possible to symmetrize the channeling of the magnetic lines on the stator side 34. Thus the measuring device is more sensitive to the movements of the relief 38 and of the support 32.

[0131] In the two embodiments of the inductive sensor, the relative movement of the magnet 56 with respect to the relief 38 due in particular to the movement of the support 32 with respect to the stator 34, modifies the magnetic flux which passes through the coil 52. By magnetic induction effect, a voltage appears at the terminals of the electric dipole formed by the coil 52.

[0132] A circumferential movement of the support 32 and its relief 38 has been shown between figures 9 and 10. Figure 9 illustrates a reference situation in which the axis of the coil 52 and the magnet 56 is centered relative to the relief 38. Figure 10 illustrates a situation of a circumferential displacement Dr of the support 32 relative to the stator 34. The axis of the coil 52 and the magnet 56 is not centered relative to the relief 38, so that the magnetic flux through the coil is not the same as in the reference situation. A voltage appears across the terminals of the electric dipole formed by the coil 52.

[0133] The detection of this voltage, for example by a measuring system, makes it possible to determine the distance separating the coil 52 from the relief 38.

[0134] Such an inductive sensor can be more easily mounted, the magnet 56 and the winding being fixed to the stator alone. Since the relief 38 itself is made of a material with high magnetic permeability, it is not necessary to provide a second part of the sensor 42 fixed to the relief 38.

[0135] It should be noted that such an inductive sensor is sensitive to the circumferential displacement of the support 32 relative to the stator 34, but that it is also sensitive to the radial displacement of the support 32 relative to the stator 34.

[0136] A second measuring assembly comprising the same inductive sensor can be provided, the two measuring assemblies being placed diametrically opposite on the support 32 relative to the X axis. The differential measurement between the two sensors would then make it possible to determine the radial movements of the support 32, and the average measurement between the two sensors would then make it possible to determine the circumferential movements of the support 32.

[0137] A capacitive proximity meter measures the distance between the object under study and a detection plate included in the proximity meter. The object and the plate form an electrical capacitor whose capacitance depends on the desired distance. The capacitance can be pre-calibrated and measured during the experiment via the oscillation frequency of an electrical circuit that involves the aforementioned capacitor.

[0138] A capacitive proximity meter evaluates the distance between the object under study and a detection plate included in the proximity meter. The object and the plate form a capacitor whose capacitance depends on the desired distance. The capacitance can be pre-calibrated before the experiment and measured during the experiment via the oscillation frequency of an electrical circuit that involves the capacitor mentioned above. For example, the detection plate is fixed to the stop 40 and thus forms a part of the sensor 42. The relief 38 plays the role of the object under study, so that the sensor does not include a second part fixed to the relief 38 or the support 32. The sensor 42 is all the simpler to mount in the speed reducer 19.

[0139] A piezoelectric sensor is a device that produces a measurable electrical signal when subjected to stress. Such a sensor can therefore measure force or torque.

[0140] An exemplary embodiment of a measuring device 36 which uses a piezoelectric sensor is illustrated in FIG. 5.

[0141] In this exemplary embodiment, four measuring assemblies 50a, 50b, 50c and 50d are arranged regularly around the X axis. Each assembly comprises a relief 38 and two bearings 40 and 46, the two bearings 40 and 46 being located on either side of the relief 38 in a circumferential direction. Between the bearing 40 and the relief 38, a piezoelectric sensor 42 is arranged so as to be in contact with both the bearing 40 and the relief 38.

[0142] Likewise, between the bearing 46 and the relief 38, a piezoelectric sensor 42 is arranged so as to be in contact with both the bearing 46 and the relief 38.

[0143] Each piezo sensor 42 is thus configured to measure a stress in the circumferential direction that the relief 38 exerts on one of the bearings which surround it.

[0144] In operation, the pair of piezo sensors provides two measurements which make it possible to evaluate the force exerted by the support 32 on the stator 34.

[0145] It should be noted that only one of the piezo sensors provides a measurement which makes it possible to evaluate the force exerted by the support 32 on the stator 34.

[0146] It should be noted that other types of strain-sensitive sensors such as magnetostrictive sensors can be used instead of a piezoelectric sensor.

[0147] It should also be noted that by using a sensor that requires it to be placed in contact between the relief 38 and one of the bearings 40, 46, there is a pre-stressing effect when mounting the sensor. The stress that is exerted by default on the sensor once it has been mounted and before the speed reducer is put into operation, has the effect of shifting the measurements subsequently produced by this sensor. It is therefore advantageous to provide a calibration on the engine at a standstill consisting of canceling the residual torque, for example by software. Furthermore, this type of contact sensor must withstand the vibrations generated by the gearing, vibrations that the support 32 undergoes and which are transmitted to the sensor.

[0148] An ultrasonic sensor is a device that is configured to send a high-frequency sound signal toward an object under study. This signal propagates from the device toward the object at the speed of sound. When the signal encounters the object, the signal is at least partially reflected and an echo signal from the initial signal propagates in the opposite direction toward the sensor. This echo signal is detected by the sensor. From the time delay between the emission of the initial signal and the detection of the echo signal, the detector determines the distance separating it from the object under study. An ultrasonic sensor may be attached to the stator 34, in particular to a bearing 40 of the stator 34. The sensor is configured to send the initial signal toward a particular portion of the support 32, in particular toward a relief 38 of the support 32.The signal is emitted towards the particular part, for example in the circumferential direction, and the detection of the echo makes it possible to determine a relative displacement between the support 32 and the stator 24, for example in the circumferential direction.

[0149] An optical sensor is a device configured to send a light signal toward an object under study. This signal propagates from the device toward the object at the speed of light. When the signal encounters the object, the signal is reflected and propagates back toward the sensor. This echo of the original signal is detected by the sensor. For example, the sensor includes a laser that creates a light spot on a surface. The sensor further includes a lens and a line of photodiodes to assess the position of the laser return.

[0150] According to another example, the sensor is of the interferometric type. The sensor comprises a coherent light source, such as a laser. The emitted light is divided into two paths, a reference path and a measurement path whose distance depends on the distance to be measured. For example, the light source is fixed to the stator 34 and the measurement path comprises a round trip against a reflective surface of a relief 38 of the support 32. The lights from the two paths are then superimposed. Due to the wave nature of light, this superposition has a brightness which depends on the phase shift between the lights from the two paths, brightness which makes it possible to establish the distance.

[0151] Alternatively, the reflection of the light signal on the object can be made dependent on the position of the object. By performing a preliminary calibration to identify a correspondence between the position of the object and the measured optical signal, the position of the object can then be determined by an optical measurement.

[0152] A particular embodiment of the non-contact proximeters is illustrated in figures 11 and in a radial configuration of the optical measurement. This embodiment is not exclusive to an optical measurement, it is valid for any non-contact proximeter. According to this embodiment produced for an optical sensor, an optical sensor 60 is fixed to the base 35 of the stator 34 radially outside a relief 38 of the support. It can be provided that for the reference position of the support 32, the optical sensor 60 is aligned radially with the relief 38, that is to say that the direction passing through the sensor 60 and the relief 38 crosses the X axis perpendicularly. The relief 38 has on the side of the sensor 60 an external radial surface 58. The sensor 60 is configured to send on this surface 58 an optical signal of which at least a part is returned to the sensor 60 and measured by the sensor 60.The surface 58 is not homogeneous so that depending on the angle around the X axis of the support 32 relative to the stator 34, the reflection of the signal is not the same. For example, the surface 58 has a particular curvature in the circumferential direction or the surface 58 is treated so that the reflection coefficient is not homogeneous in the circumferential direction. Thus, when the support 32 rotates, the signal detected by the sensor 60 changes. By performing a preliminary calibration, it is possible to relate the displacement as a function of the measured signal. The preliminary calibration can be performed by varying the displacement and measuring the corresponding signal. It is also possible to perform a preliminary calibration by varying the force or torque exerted by the support 32 on the stator and measuring the corresponding signal. The force or torque corresponds to a particular displacement of the support 32 relative to the stator 34.In all cases, a calibration curve 62 is obtained linking the measurement, i.e. the value of the signal measured by the sensor 60, to the torque or force exerted by the support 32 on the stator 34, or a calibration curve linking the measurement, i.e. the value of the signal measured by the sensor 60, to the displacement of the support 32 relative to the stator 34.

[0153] Figures 11 and 12 illustrate an example of a calibration curve 62 relating the measurement to the torque exerted by the support 32 on the stator 34.

[0154] Figure 11 illustrates a reference situation where the sensor 60 is radially aligned with the sensor 38. The optical signal reaches the point 64C of the surface 58, it is returned to the sensor 60 which measures a value 64B which appears on the ordinate of the curve 62. This ordinate 64B corresponds to the point 64 of the calibration curve, point 64 whose abscissa 64A gives the value of the torque exerted by the support 32 on the stator 34.

[0155] Figure 12 illustrates an offset situation where the sensor 60 is no longer radially aligned with the sensor 38. The optical signal reaches the point 66C of the surface 58, it is returned to the sensor 60 which measures a value 66B which appears on the ordinate of the same curve 62. This ordinate 66B corresponds to the point 66 of the calibration curve, point 66 whose abscissa 66A gives the value of the torque exerted by the support 32 on the stator 34. The difference between the torque values ​​66A and 64A gives the difference in torque exerted by the support 32 on the stator 34, a difference in torque which corresponds to the displacement of the support 32 relative to the stator 34 between the reference situation and the offset situation.

[0156] It should be noted that here the surface 58 has been chosen to be symmetrical with respect to its center which corresponds to the point 64C. In this case the calibration curve linking the measurement, that is to say the value of the signal measured by the sensor 60, to the displacement of the support 32 with respect to the stator 34 is symmetrical with respect to the reference situation where the light signal arrives at the point 64C. An angular displacement of a certain value in one direction or another will produce the same optical signal.

[0157] It is possible to choose a surface 58 whose optical inhomogeneity is not symmetrical with respect to its center which corresponds to point 64C. In this case the calibration curve linking the measurement, that is to say the value of the signal measured by the sensor 60, to the displacement of the support 32 with respect to the stator 34 is not symmetrical with respect to the reference situation where the light signal arrives at point 64C.

[0158] An LVDT sensor - abbreviation of the English expression "Linear Variable Displacement Transducer" translated into French as Linear Variable Displacement Transducer - is an electromechanical device used to convert a rectilinear mechanical movement into an electrical voltage. The operating principle of the LVDT sensor is as follows. The LVDT sensor comprises a primary coil which is excited by an alternating current. The LVDT sensor comprises two secondary coils positioned on either side of the primary coil, the three coils being coaxial along an axis of the LVDT sensor. In relation to Figure 6, the LVDT sensor comprises a part 42a fixed to the stator 34 for example to the base 35 or to a stop 40 and a part 42b fixed to the support 32, for example to the body 33 or to a relief 38. In these two fixings, the sensor is mounted according to an axis pivot connection which can be parallel to the X axis.The LVDT sensor comprises a rod secured to one of the parts fixed to the stator 34 or to the support 32, the rod being mounted movably along the axis of the LVDT sensor relative to the other of the fixed parts. During movement of the rod, it passes more or less through the three coils. Depending on the relative movement of the support 32 relative to the stator 34, the LVDT sensor changes position: on the one hand the distance between the fixed parts changes and on the other hand the angle of the rod relative to the stator 34 changes. The movement of the rod modifies the magnetic coupling of each secondary coil with the primary coil. The voltages due to the induction effect at the terminals of the secondary coils can be measured, transmitted via the connections 42c and compared, which makes it possible to reconstruct the position of the LVDT sensor. The LVDT sensor gives a measurement of circumferential displacement of the support 32 relative to the stator 34.But it is also possible, via calibration, to determine a torque exerted by the support 32 on the stator 34 from the measurement of the LVDT sensor. It should be noted that the angle of the LVDT sensor in its reference position can be chosen to maximize the sensitivity to the torque.

[0159] The LVDT sensor needs to be fixed for a first part on the stator 34 and for a second part on the support 32. On the other hand, the LVDT sensor is not necessarily fixed to a relief 38 or to a stopper 40.

[0160] Alternatively, the LVDT sensor can be replaced by an RVDT sensor - an abbreviation of the English expression "Rotary Variable Displacement Transducer". The RVDT sensor is an electromechanical device used to convert mechanical rotational movement into voltage. This time, it is the rotation of a part of the sensor that changes the coupling between the primary coil and the secondary windings.

[0161] Finally, it is possible to use one sensor per hydraulic cylinder. Such a sensor has a first part 42a fixed to the stator 34 and a second part 42b fixed to the support 32. The first part 42a and the first part 42a are connected together by a set of cylinders. These cylinders are controlled so as to maintain the first part 42a and the second part 42b at a certain position relative to each other. In particular, a regulated system can be used which adjusts the pressure in each cylinder according to a measurement of the relative position between the first part 42a and the second part 42b. The adjusted pressure in the cylinder is an indirect measurement of the torque.

[0162] The measuring device 36 may comprise a combination of several types of sensors, for example to have a wider measurement range at a given precision, or to combine information on different parameters.

Claims

CLAIMS 1. Aeronautical propulsion system (1) comprising: a stator (34), a drive shaft (30), a fan section (2) comprising a fan shaft (20) and a fan rotor (9), the fan rotor (9) being configured to be driven in rotation by the fan shaft (20), a speed reduction device (19) coupling in rotation the drive shaft (30) and the fan shaft (20), so as to drive the fan shaft (20) at a rotational speed lower than a rotational speed of the drive shaft (30), the reduction device (19) comprising: -- a solar gable (19a), -- a crown (19b), a diameter of the crown being greater than a diameter of the sun pinion, -- a satellite carrier (19d), -- at least one satellite pinion (19c) rotatably mounted on the satellite carrier (19d), and -- a support (32) fixed to the stator (34), the crown (19b) or the satellite carrier (19d) being kept fixed in rotation relative to the support (32), the propulsion system (1) comprising a measuring device (36) configured to measure: -- a relative displacement between the support (32) and the stator (34), or / and -- a force exerted by the support (32) on the stator (34), the support (32) comprising a body (33) and a relief (38) which projects radially from the body (33) relative to an axis (X) of rotation of the sun gear (19a), the stator (34) comprising a base (35) and a stopper (40) which projects radially from the base (35), the stopper (40) being arranged, circumferentially relative to the axis (X) of rotation, in vis- opposite the relief (38), the measuring device (36) comprising at least one sensor (42), the at least one sensor comprising a portion (42a) mounted on one of the stopper (40) and the relief (38), the propulsion system (1) comprising a measuring assembly (50a) comprising the relief (38), the stopper (40) and the at least one sensor (42), the measuring assembly (50a) comprising a second stopper (46) of the stator (34), the second stopper (46) extending radially from the base (35), the second stopper (46) being arranged circumferentially opposite the relief (38), the relief (38) being located circumferentially between the first stopper (40) and the second stopper (46).

2. Propulsion system (1) according to claim 1 wherein the measuring device is configured to measure the relative displacement and / or the force as a function of time.

3. Propulsion system (1) according to any one of claims 1 to 2 wherein the relative displacement and the force are measured in a circumferential direction relative to an axis (X) of rotation of the sun gear (19a).

4. Propulsion system (1) according to any one of claims 1 to 3 wherein the part (42a) of the at least one sensor (42) is a first part, the at least one sensor (42) comprising a second part (42b) mounted on the other element among the stopper (40) and the relief (38).

5. Propulsion system (1) according to any one of claims 1 to 4, in which the measuring assembly (50a) comprises two sensors (42, 48) situated circumferentially on either side of the relief (38), each of the sensors (42, 48) cooperating respectively with a single stopper among the first stopper (40) and the second stopper (46).

6. Propulsion system (1) according to any one of claims 1 to 5 wherein the measuring assembly (50a) comprises a sensor configured to measure the relative displacement and a sensor configured to measure the force.

7. Propulsion system (1) according to any one of claims 1 to 6 wherein the measuring assembly (50a) is a first measuring assembly (50a), of a plurality of measuring assemblies (50a, 50b, 50c, 50d) included in the system (1) and regularly distributed circumferentially, for example the system comprising two assemblies which are diametrically opposite each other.

8. Propulsion system (1) according to any one of claims 1 to 7 in which the measuring device comprises at least one sensor chosen from: - a proximity sensor, such as a magnetic proximity sensor, an inductive proximity sensor or a capacitive proximity sensor, - a piezoelectric sensor, - an ultrasonic sensor, - an optical sensor, - an LVDT type sensor, - an RVDT type sensor, and - a hydraulic cylinder sensor.

9. Aircraft comprising a propulsion system (1) according to one of claims 1 to 8.

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