Electric hybrid propulsion unit for an aircraft equipped with an electromechanical feathering device

Abstract

The invention relates to a propulsion unit (1) for an aircraft, comprising: - a propeller, of longitudinal axis, provided with blades (6) of variable pitch angle, - an electric motor for driving the rotation of the propeller, - a control mechanism (14) for controlling the pitch angle of the blades, movable between a feathering position and a propulsion position, - a control rod (16) secured in terms of translation to the control mechanism and passing axially through the electric motor in order to have a downstream end (16b) at the opposite end from the propeller, and - a feathering device (40) equipped with an actuator (41) connected to an electric power supply source and to the control rod, the actuator being configured to move the control rod towards the feathering position according to the state of the electric motor and to maintain the feathering position.

Description

[0001] DESCRIPTION

[0002] TITLE: HYBRID ELECTRIC PROPELLER ASSEMBLY FOR AIRCRAFT EQUIPPED WITH AN ELECTROMECHANICAL FEATHERING DEVICE

[0003] Scope of the invention

[0004] The present invention relates to the field of distributed hybrid-electric propulsion for aircraft. It also relates to an aircraft comprising such a hybrid-electric propulsion system.

[0005] Technical background

[0006] Prior art includes documents EP-A1-4201810, CN-B-113320686, JP-A-2022033690, US-A1-2022 / 289371 and US-A1-2022 / 094297.

[0007] Current aircraft equipped with thermal propulsion systems are among the largest emitters of greenhouse gases that affect the climate. Hybridization and electrification are ways to reduce greenhouse gas emissions, particularly in the aeronautical sector. An aircraft propulsion system generally includes a propeller or fan driven by a gas turbine to move the aircraft. Electric hybridization involves combining the technologies of fossil fuel-powered combustion engines and electric motors.

[0008] Electrical machines, for example, are electromechanical devices based on electromagnetism that convert electrical energy into mechanical energy (motor mode) or, conversely, produce electricity from mechanical energy (generator mode). An electrical machine can operate in both generator and motor modes.

[0009] The available electrical energy is generally used to power various aircraft equipment, which for example reduces mass and maintenance costs, but could also at least partially power a propeller or fan for propulsion.

[0010] Summary of the invention

[0011] The objective of the present invention is to provide a solution enabling, on the one hand, the feathering of the blades of a propeller of an electric propulsion assembly, autonomously and independently, and on the other hand, ensuring the simple maintenance of the feathering position.

[0012] We achieve this objective in accordance with the invention by means of an aircraft propulsion system, comprising:

[0013] - a propeller, with a longitudinal axis, equipped with blades with a variable pitch angle,

[0014] - an electric motor to drive the propeller's rotation and electrically controlled by a control unit,

[0015] - a blade pitch angle control mechanism, located in a propeller hub, which can be moved translationally along the longitudinal axis between a feathering position and a propulsion position corresponding to a blade angle adapted to the aircraft's propulsion,

[0016] - a control rod for the movement of the mechanism, which is fixedly connected in translation to the control mechanism and which passes axially through the electric motor to present a downstream end positioned on the side opposite the propeller relative to the electric motor, and

[0017] - a feathering device equipped with an actuator which is connected to an electrical power source and which is connected to a downstream end of the control rod, the actuator being configured to move the control rod and the control mechanism to the feathering position in response to a control unit command relating to a state of the electric motor and to maintain the feathering position.

[0018] Thus, this solution achieves the aforementioned objective. In particular, such a configuration is simple and of the on / off type. The control mechanism can be in a propulsion position by default, and the electromechanical feathering device coupled to the control rod allows the control rod to be moved to reverse the position of the control mechanism using a conventional electrical source.

[0019] The propulsion system assembly also includes one or more of the following features, taken alone or in combination:

[0020] - the control mechanism includes a control ring centered on the longitudinal axis and connected to the propeller blades via linkage elements, the control ring being driven in rotation by the propeller hub.

[0021] - The actuator is mounted on a chassis which is attached to a housing of the electric motor. - The feathering device includes a connecting rod which is articulated on one side to the downstream end of the control rod and on the other side to a moving part of the actuator.

[0022] - the connecting rod has a length measured between a first end and a second end, the moving part of the actuator being connected at the center of the length of the connecting rod, the first end of the connecting rod being articulated to the downstream end of the control rod and the second end of the connecting rod being articulated on the chassis.

[0023] - the assembly includes a time-delay relay connected to the control unit and capable of occupying, in response to a command from the control unit, an active state allowing the actuator to switch to a position to move the control rod into the feathering position.

[0024] - the assembly includes a time-delay relay electrically connected to a manually activated control button and capable of occupying, in response to the activation of the control button, an active state allowing the actuator to switch to a position to move the control rod into the feathering position.

[0025] - the control ring is against a first stop to limit the stroke of the moving part in the feathering position or is against a second stop to limit the stroke of the moving part in the propulsion position.

[0026] - the actuator includes a torque limiter which is configured to disengage the moving part after it has moved into a retracted or deployed position.

[0027] - a return spring located in the propeller hub is capable of acting on the control mechanism so as to force the control mechanism to move to a feathering position of the blades in the event of actuator failure.

[0028] - the return spring is mounted to rotate securely with the control ring, the control rod having an upstream part passing through the control ring and which rotates relative to the upstream part via bearings.

[0029] - the bearing supports include an upstream radial bearing and a downstream axial bearing, the upstream bearing comprising an inner ring attached to the upstream part of the control rod and an outer ring attached to the control ring, the downstream bearing comprising an upstream ring attached to the control ring and a downstream ring attached to the upstream part of the control rod, -the actuator is irreversible.

[0030] - The actuator includes a movable part capable of moving between a deployed position corresponding to the propulsion position and a retracted position corresponding to the feathering position. — The actuator includes a movable part capable of moving between a deployed position corresponding to the feathering position and a retracted position corresponding to the propulsion position.

[0031] -- the disengagement of the moving part is carried out after the control means has come to a stop against the first stop or against the second stop.

[0032] -- the control unit is integrated into the electric motor.

[0033] -- the actuator is connected to a power supply.

[0034] -- the power supply is arranged in the propulsion assembly.- the linkage elements include at least one pin which is attached to a blade root and which is housed in a cavity of the control ring.

[0035] - - the connecting elements include connecting rods, each having a first end connected to a blade root and a second end connected to the control ring.

[0036] - - , the control rod includes a device for adjusting its length.

[0037] - - the actuator includes a disengageable element.

[0038] - - the actuator includes a disengageable movable part connected to the control rod which is configured to occupy a deployed or retracted position in which an electric motor of the actuator and means for moving the movable part are disconnected or connected so as to maintain the position of the control rod.

[0039] The invention also relates to an aircraft wing comprising at least one propulsion assembly as mentioned above.

[0040] The invention further relates to an aircraft comprising at least one wing as mentioned above or at least one assembly as mentioned above.

[0041] Depending on the aircraft, the control unit is installed in the aircraft.

[0042] Depending on the aircraft, the power supply is arranged within the aircraft.

[0043] The invention may also relate to a method for operating a feathering device for a propulsion assembly as described above. The method comprises a step of moving the control rod and the control mechanism according to a predetermined state of the electric motor so as to drive the propeller blades into a feathered position.

[0044] The process optionally includes a step of sending information representative of the state of the electric motor to the control unit.

[0045] The method optionally includes a step of sending a control signal to the actuator to move the control rod. The method also optionally includes a step of supplying power to the actuator for a predetermined duration.

[0046] Brief description of the figures

[0047] The invention will be better understood, and other objects, details, features and advantages thereof will become more apparent upon reading the detailed explanatory description that follows, of embodiments of the invention given by way of purely illustrative and non-limiting examples, with reference to the accompanying schematic drawings in which:

[0048] Figure 1 is a perspective view of an aircraft wing comprising several propulsion assemblies according to the invention;

[0049] Figure 2 is an axial cross-sectional view of an example of a propulsion assembly mounted on an aircraft according to the invention;

[0050] Figure 3 is a partial axial cross-sectional view of a propeller, a mechanism for controlling the angles of the propeller blades and a feathering device according to the invention;

[0051] Figure 4 is a perspective and transparent view of a connecting means linking the feet of the blades of a propeller to a control ring of a control mechanism according to the invention;

[0052] Figure 5 is a detailed view of a propeller blade control mechanism as shown in Figure 3;

[0053] Figure 6 is a perspective and rear view of an example of a feathering device mounted in a propulsion assembly;

[0054] Figure 7 is an axial cross-sectional view of a chassis of the feathering device according to figure 6 mounted on a housing of an electric motor;

[0055] Figure 8 is a perspective and detail view of an example of a flagging device according to the invention;

[0056] Figure 9 represents a synoptic diagram of the relationships between an electric motor driving the propeller, the feathering device and the control unit and at least one electrical source according to the invention;

[0057] Figure 10 shows a control mechanism in the propulsion position according to the invention; and

[0058] Figure 11 represents a control mechanism in the feathering position according to the invention.

[0059] Detailed description of the invention The invention applies to a distributed electric propulsion assembly 1 comprising a propeller 2 or blower with variable pitch blades.

[0060] In this application, the term "distributed" means that the motive power required for propulsion is distributed over several drive units.

[0061] The propulsion unit 1 is intended to equip, for example, an aircraft 3, and preferably an airplane, in order to provide thrust for the aircraft's movement. The aircraft 3 comprises, as is known, two wings 4 arranged on either side of a fuselage (not shown), and each wing 4 is equipped with at least one propulsion unit 1.

[0062] In the remainder of the invention, the term "propeller" is used to refer indifferently to a blower or a propeller.

[0063] Figure 1 shows an example of an aircraft wing 4. The wing 4 extends along a span direction A and is equipped with three propulsion assemblies 1 which are distributed along the span direction A. The propulsion assemblies 1 are advantageously arranged on a leading edge 5 of the wing 4. The leading edge 5 is called the leading edge.

[0064] In the present invention, and generally, the terms "upstream" and "downstream" are defined with respect to the airflow and with respect to the aircraft, as well as here along a longitudinal axis X. The terms "axial" and "axially" are also defined with respect to the longitudinal axis X. Similarly, the terms "radial", "internal" and "external" are defined with respect to a radial axis Z perpendicular to the longitudinal axis X and with respect to the distance from the longitudinal axis X.

[0065] Each propulsion unit 1 comprises a propeller 2 with a longitudinal axis X and equipped with blades 6 with variable pitch angles. The variable pitch of the blades improves the performance of each propulsion unit 1.

[0066] Advantageously, but not exclusively, the six propeller blades shown here are not shrouded. Alternatively, the six blades may be shrouded by a propeller housing (not shown).

[0067] Each propeller 2 extends radially outwards from a hub 7 covered, for example, by a first nacelle portion 8a. This first nacelle portion 8a is rotating because it is connected to the propeller hub 7 and is generally known as the "propeller cone." Each propeller 2 advantageously propels air outwards from the first nacelle portion 8a to provide the required thrust. Each first nacelle portion 8a is substantially cylindrical and extends along the longitudinal axis X.

[0068] Each propeller 2 comprises, for example, three blades 6 as shown in Figure 1. Of course, the propellers 2 could comprise a different number of blades 6.

[0069] Referring to Figure 2, each propeller 2 is driven in rotation around the longitudinal axis X by an electric motor 10. This motor is advantageously, but not exclusively, enclosed by a second nacelle section 8b. This second nacelle section 8b extends downstream from the first nacelle section 8a. In this embodiment, the second nacelle section 8b is substantially cylindrical and extends along the longitudinal axis X. The electric motor 10 can be powered, for example, by an electrical power source 59 such as a battery, a turbogenerator, or a conventional generator set.

[0070] Advantageously, the electric motor 10 is designed to be controlled by an electronic control unit 11. The control unit 11 may optionally control its power supply. Advantageously, the electric motor 10 is electrically connected to the control unit 11. The control unit 11 can receive information relating to the operating state or operating parameters of the electric motor 10 and thus send it control commands.

[0071] Advantageously, but not exclusively, the control unit 11 is installed in the aircraft. Alternatively, the control unit 11 is integrated into the electric motor 10; the latter is considered, for example, as a smart motor.

[0072] The hub 7 includes, for example, housings (not shown) which are intended to receive the foot 13 of the blades 6 so that they can be rotated around a shimming axis B. The shimming axis B is, without limitation, parallel to the radial axis Z.

[0073] The variable-pitch blades 6 can occupy different angular positions depending on the operating conditions of the propulsion system 1 and the flight phases involved. Each blade 6 pivots between a working position (thrust position) and an extreme feathering position. In particular, in the thrust position, also known as the "flight pitch" position (or propulsion position), the propeller blades 6 of the propeller 2 generate thrust to contribute to the aircraft's forward movement and each has a pitch angle, for example, of 30° relative to the plane of rotation. In the extreme feathering position, the blades 6 are then at the optimal angle relative to the aircraft's direction of travel, for example, in the event of a failure of the propulsion system 1. This helps to limit aerodynamic drag and its potential rotation due to entrainment (wind turbine operating mode).In this last position, the blade pitch angle is positive, and is generally around 90° relative to the plane of rotation of the blades.

[0074] With reference to Figures 3 and 4, the propulsion assembly 1 includes a control mechanism 14 for the pitch angle of the blades 6. The control mechanism 14 is advantageously, but not exclusively, located in the hub 7. The control mechanism 14 includes, for example, a control ring 15 which is centered on the longitudinal axis X and connecting elements 33 which connect the blades 6 to the control ring 15. The control ring 15 is advantageously located radially inside the hub 7.

[0075] The connecting elements 33 are advantageously, but not limited to, at least one pin 33b (also shown in Figures 8 and 9) which is attached to a blade foot 13 and which is housed in a cavity 15b (also shown in Figures 8 and 9) of the control ring 15. The cavity 15b opens onto a radially external surface 15a of the control ring 15 or is delimited by two walls which extend from the radially external surface of the control ring 15.

[0076] The connecting elements 33 may include connecting rods 33a. Each connecting rod 33a in this example comprises a first end connected to a blade root 13 of a blade 6 and a second end connected to the control ring 15 via the pin 33b, for example. Other connecting elements 33 that suitably connect the blade roots to the control ring 15 are possible.

[0077] In this example, the control ring 15 is driven in rotation about the longitudinal axis X by the hub 7. Optionally, the control ring 15 is connected to the hub 7 via a ferrule 12. The ferrule 12 is, but not limited to, annular. In particular, the ferrule 12 (also visible in Figures 10 and 11) comprises, for example, a first portion 12a that extends axially and a second portion 12b that extends substantially radially from the first portion 12a.

[0078] Advantageously, the ferrule 12 has a substantially L-shaped form. The second portion 12b may be curved. The second portion 12a is advantageously fixed to a downstream wall 7b of the hub 7. The downstream wall 7b is preferably connected to an upstream wall 7a of the hub 7. The first portion 12a is mounted on the control ring 15, which can slide relative to the ferrule 12. The sliding motion can be achieved using splines.

[0079] In Figures 3 to 5, the propulsion assembly 1 includes a control rod 16 that acts on the control mechanism 14. In particular, the control rod 16 extends along the longitudinal axis X between an upstream end 16a and a downstream end 16b. The control rod 16 passes axially through the electric motor 10, as can be seen in Figure 2. The upstream end 16a and the downstream end 16b are optionally located on either side of the electric motor 10 axially. More precisely, the control rod 16 includes an upstream portion 17 that is integral with the control ring 15. The control rod 16 drives the movement of the control mechanism 14, to which it is integrally connected. In other words, the control mechanism 14 moves between the feathering position and the propulsion position.

[0080] The upstream portion 17 passes through the control ring 15, which rotates relative to the upstream portion 17, via at least one bearing. The control ring 15 includes, but is not limited to, a bore 18 extending along the longitudinal axis X. In this example, the upstream portion 17 carries the upstream end 16a of the control rod 16. Preferably, there are two bearings, illustrated in this figure, which are designated upstream bearing 19a and downstream bearing 19b.

[0081] Advantageously, but not exclusively, the upstream bearing 19a is a radial bearing and the downstream bearing 19b is an axial bearing (commonly called a thrust ball bearing). This arrangement allows for the absorption of both radial and axial loads.

[0082] Still in Figure 2, the upstream bearing 19a comprises, for example, an inner ring 20a which is fixed to the upstream portion 17 of the control rod 16 and an outer ring 20b which is fixed to the control ring 15. The outer ring 20b advantageously surrounds the inner ring 20a radially. Rolling elements 20c, preferably balls, are arranged between the outer and inner rings 20a, 20b. Optionally, the control ring 15 includes a recess 21 which opens into the bore 18 and onto an upstream lateral surface 22. The outer ring 20b is housed in this recess 21. The downstream bearing 19b comprises, for example, an upstream ring 23a fixed to the control ring 15 and a downstream ring 23b fixed to the upstream part 17 of the control rod 16. In this example, the upstream ring 23a is arranged axially upstream of the downstream ring 23b. Rolling elements 23c, preferably balls, are arranged between the upstream and downstream rings 23a, 23b.Optionally, the control ring 15 includes a recess 24 centered on the longitudinal axis. The recess 24 opens, on one side, into the bore 18 and, on the other, onto a downstream lateral surface 25 of the control ring 15. The downstream lateral surface 25 is axially opposed to the upstream surface 22. The upstream ring 23a is housed in the recess 24. The downstream ring 23b is, for example, axially blocked by a stop surface 26 supported by a shoulder 27 (see Figure 4) of the upstream portion 17 of the control rod 16.

[0083] Advantageously, but not exclusively, the upstream and downstream bearings 19a, 19b are lubricated with lubricant to ensure their performance and extend their service life. The lubricant is, for example, oil or grease.

[0084] Referring to Figure 5, a cover 28 is rotationally fixed to the control ring 15. The cover 28 is configured to isolate the lubricant at this point. The cover 28 is also configured to act as a stop for the propulsion (or flight) position. The cover 28 is mounted upstream of the control rod 16 and the upstream bearing 19a. For this purpose, the control ring 15 includes, for example, a first wall 29 extending from the upstream lateral surface 22 along the longitudinal axis X. The first wall 29 advantageously surrounds the opening of the recess 21. In other words, the first wall 29 is cylindrical and advantageously has a circular cross-section. The hood 28 includes a base 30 and a skirt 31 which extends from the base 30 along an axis of revolution C. The skirt 31 includes a free edge 32 which delimits an opening 33 leading into the interior of the hood 28.The skirt 31 is installed inside the first wall 29 of the control ring 15 and coaxially with the longitudinal axis X. The free edge 32 of the hood 28 is in contact with a portion of the upstream lateral surface 22. The hood 28 allows the lubricant to be contained at least in the upstream bearing 19a.

[0085] According to an advantageous, but not limiting, feature, and as shown in Figure 5, the control ring 15 comprises a second wall 34 extending from the downstream lateral surface 25 along the longitudinal axis X. The second wall 34 encloses at least part of the upstream portion 17 of the control rod 16. The second wall 34 further extends inside a hollow shaft section 35 that is integral, on one side, with the hub 7, and on the other side, with a drive shaft 49 of the electric motor 10, which is also hollow. The control rod 16 extends through the shaft section 35 and the drive shaft 49. This area is preferably sealed, i.e., there is no lubrication circuit. Nevertheless, a lubricant may be present and contained around the control rod 16.

[0086] In Figures 3 and 5, the control rod 16 includes, for example, a downstream portion 36 which is connected to a feathering device 40 described later. The downstream portion 36 carries the downstream end 16b (of the control rod 16). Advantageously, but not exclusively, the upstream portion 17 and the downstream portion 36 are connected to each other via a hinged joint 37. This helps to contain misalignments during the movement of the control rod 16. The hinged joint 37 is, for example, a ball joint or a universal joint.

[0087] According to an optional feature, the control rod 16 includes a length adjustment device 38. For this purpose, the downstream portion 36 includes an upstream end 16bb which is equipped with a threaded rod 39a. The latter has a first end 39aa (free) which is housed in a bore 17a of a downstream end 16aa of the upstream portion 17. The downstream end 16aa is opposite the upstream end 16a of the upstream portion 17. The first end 39aa of the threaded rod 39a is hinged in the downstream end 16aa so as to form the hinged joint 38.

[0088] The threaded rod 39a advantageously comprises a second end 39ab (axially opposite to the first end 39aa) which is screwed into a bore 36a of the upstream end 16bb of the downstream portion 37. The threaded rod 39a extends along the longitudinal axis X. Advantageously, the threaded rod 39a extends between the upstream portion 17 and the downstream portion 36, and preferably between the bore 17a of the upstream portion 17 and the bore 36a of the downstream portion 36. A locking nut 39b advantageously secures the threaded rod 39a to the downstream portion 36. This length adjustment device 38 allows the length of the control rod 16 to be adjusted during the assembly of the locking system 50 in order to obtain precise alignment of the blades 6, particularly in the propulsion position.

[0089] With reference to Figure 6, the propulsion assembly 1 includes a feathering device 40 for the blades 6 of the propeller 2. The feathering of the propeller blades 6 reduces the overall drag of the propulsion assemblies 1 which can occur in certain phases of flight where the propellers are not used for the propulsion of the aircraft (for example to limit the free rotation of the blades 6 by the wind (Windmilling).

[0090] In the example shown, each wing 4 of the aircraft carries three propulsion units 1, whose freely rotating propellers 2, positioned frontally relative to the wing 4, could significantly impact the aircraft's drag and performance. Feathering also allows for the management of potentially dangerous events in the electrical system (presence of abnormal voltage, passivation of short circuits). Indeed, short circuits can occur, for example, in the electric motor 10; the free rotation of the propeller due to the airflow passing through it (windmilling) could continue to power the short circuit and generate high voltage / current levels in the electrical lines. Feathering the blades of propeller 2 allows for a simple and effective way to limit or even stop the rotation of the propeller blades to avoid overvoltages, potentially high short-circuit currents, and drag.

[0091] Advantageously, the feathering device 40 is equipped with an actuator 41 connected to a power supply 42 and to the control rod 16. The actuator 41 is configured to move the control rod 16 and the control mechanism 14 to the feathered position in response, for example, to a command from the control unit 11 relating to the state of the electric motor 10, and to maintain (lock) the feathered position. The command may originate from an operator such as the pilot. The feathered position is advantageously maintained as long as the actuator 41 is not powered.

[0092] With reference to Figures 6 to 8, the actuator 41 is advantageously mounted on a frame 43 which is fixed to a housing 44 of the electric motor 10. In this way, each feathering device 40, in particular the actuator 41, is self-supporting by a drive assembly 1. The frame 43 includes, for example, at least one flange 45 which has a median plane perpendicular to the longitudinal axis X. In the present example, there are four flanges 45. Each flange 45 is mounted on the housing 44 using fasteners 46 such as bolts, screws, or other suitable components allowing for easy and quick assembly and disassembly of the frame 43.

[0093] Advantageously, but not exclusively, pads 47, for example made of elastomer, can be provided to cooperate with the fasteners in order to reduce vibrations. According to one embodiment, a pad 47 can be mounted on a threaded rod or a screw of the fastener 46, and on either side of the flange 45.

[0094] Figure 8 shows a specific example of a chassis 43. This chassis comprises a first wall 48 and a second wall 49 which are advantageously, but not exclusively, parallel to each other and to the longitudinal axis X. The first and second walls 48, 49 are positioned at a distance from each other. This creates a space 51 to house the actuator 41.

[0095] Advantageously, the median planes of the first and second walls 48, 49 are each perpendicular to the median plane of the flanges 45. Advantageously, a first partition 52 connects the first wall 48 and the second wall 49 at their first ends 48a, 49a, and preferably at their upper corners 48aa, 49aa. A second partition (not shown) connects the first wall 48 and the second wall 49 at their first ends 48a, 49a, and preferably at their lower corners 48ab. The first partition 52 and the second partition are, for example, radially opposed and form an opening into space 51, allowing the control rod 16 to pass through space 51 of the frame 43. The frame 43 could comprise only the first wall 48 at its first ends 48a, 49a.

[0096] The flanges 45 extend advantageously from the lower and upper corners 48aa, 49aa, 48ab, 49ab of the first ends.

[0097] The first and second walls 48, 49 are optionally connected at their second ends 48b, 49b to a third partition 53. This partition extends the full height of the second ends. The first partition 52 advantageously includes a median plane that is perpendicular to the longitudinal axis X. The third partition 53 includes, for example, a through opening 54 that opens into space 50, optionally.

[0098] The actuator 41 comprises a fixed body 55 and a moving part 56 relative to the fixed body 55. Advantageously, but not exclusively, the actuator 41 is linear and electrically actuated. Such an actuator 41 is easily mounted in the propulsion assembly 1 without affecting the surrounding components. Of course, the actuator 41 could be either pneumatic or hydraulic. As previously mentioned, the actuator 41 is connected to a power supply 42. The power supply 42 can be located in the aircraft or, alternatively, in the propulsion assembly. The power supply 42 can be the aircraft's electrical system or a battery (e.g., low voltage). The battery can be installed in the aircraft or in the propulsion assembly. The power supply 42 can deliver a voltage of approximately 28V.

[0099] Advantageously, but not exclusively, the power supply 42 of the actuator 41 is separate from the power supply 59 of the electric motor 10. This improves safety conditions, particularly in terms of energy availability, in the event of a failure in the electric motor 10.

[0100] Advantageously, the moving body 56, for example a piston or a moving rod, moves in translation along the longitudinal axis X. The moving body 56 slides inside the fixed body 55. The fixed body 55, for example a parallelepiped or cylindrical housing, is advantageously fixed to the frame 43 and preferably on the side of the third partition 53. Advantageously, the moving member 56 moves between a deployed position and a retracted position, for example, by means of a rotating electric motor (not shown) and a displacement mechanism, for example, a high-ratio screw-nut system (not shown), which are housed in the fixed member 55 and powered by the electrical supply 42.

[0101] Referring to Figure 8, the moving member 56 includes a free end 57 which is connected to the downstream end 16b of the control rod 16. Thus, the movement of the moving member 56 causes the movement of the control rod 16 and the control mechanism 14 to move, in particular towards the feathered position. The movement of the control rod 16 is preferably a translation along the longitudinal axis X.

[0102] Advantageously, but not exclusively, the feathering device 40 includes a connecting rod 58 which is kinematically arranged between the downstream end 16b of the control rod 16 and the moving member 56. The connecting rod 58 is articulated on both the downstream end 16b and the moving member 56. The arrangement of the connecting rod 58 provides greater latitude in adjusting the actuation force of the actuator 41 and gives an additional degree of freedom in the ratio of actuator shaft stroke to effective stroke of the control rod 16. Of course, the connecting rod 58 is optional, and the control rod 16 can be connected directly to the moving member 56. In the present example, the connecting rod 58 extends between a first end 58a and a second end 58b. Advantageously, the first end 58a is articulated to the downstream end 16b of the control rod 16. The articulated joint is advantageously a ball joint.This allows for an additional degree of freedom. Alternatively, the joint can be a pivot joint. The first end 58a, in the example shown, comprises a yoke with two lugs that lie in a plane perpendicular to the longitudinal axis. The downstream end 16b of the control rod 16 extends, for example, between the two lugs, which are traversed by a pivot axis. This pivot axis is perpendicular to the longitudinal axis X.

[0103] In this example, the second end 58b of the connecting rod 58 is articulated on the frame 43. Preferably, the articulation is achieved using a pivot joint. The first wall 48 and the second wall 49 are each traversed by a pivot pin 60 whose axis is perpendicular to the longitudinal axis. The second end 58b is mounted on the pivot pin 60. Bearings may be provided in the first and second walls 48, 49 to facilitate the rotation of the pivot pin 60.

[0104] The free end 57 of the moving member 56 is advantageously, but not exclusively, articulated at the midpoint of the connecting rod 58. The length of the connecting rod 58 is measured between the first end 58a and the second end 58b. The force of the actuator 41 is applied at the midpoint of the connecting rod 58 to reduce its overall size and achieve a better torque-to-stroke ratio of the actuator 41 to the movement of the moving member 56. Advantageously, the articulated joint is a ball joint. This provides an additional degree of freedom. The articulated joint could also be a pivot joint.

[0105] Alternatively, the free end 57 of the moving member 56 could be articulated to the second end 58b of the connecting rod 58 and the connecting rod 58 would be articulated relative to the chassis 43 at the center of its length.

[0106] Figure 9 shows a block diagram of the various electrical connections between the electric motor 10, the actuator 41, the control unit 11, and the power supply 42. A feathering procedure can be based on this block diagram. The electric motor 10 is electrically connected to the control unit 11. The voltage flowing through the control unit 11 is advantageously higher than that of the power supply 42. The control unit 11 can be the FADEC (Full Authority Digital Engine Control) which manages the power electronics in the aircraft, the propulsion assemblies 1, and the turbomachine based on signals or information relating to parameters acquired by the various components, and which sends control laws / commands to these various components, etc.

[0107] The method includes a step of sending information relating to a predetermined state of the electric motor to the control unit 11. The predetermined state may be a fault or a failure. The fault may be, for example, a short circuit in the winding of the electric motor 10. Alternatively, the information may relate to a situation in the aircraft's environment. The transmission of the information is carried out, for example, via at least one CAN data bus that communicates with the control unit 11.

[0108] The method includes a step of moving the control rod 16 and the control mechanism 14 according to a predetermined state of the electric motor 10 so as to move the propeller blades into a position, preferably the feathered position. For this purpose, the control unit 11 sends a command to the actuator 41 to move the control rod 16. Advantageously, the command controls the electrical supply to the actuator 41. Advantageously, but not exclusively, the command is transmitted to a time-delay relay 61, which controls the electrical supply 42 to the actuator 41. Generally, the time-delay relay 61 can be in an active state and a rest state. Advantageously, the transition from an active state to a rest state of the time-delay relay 61 allows the control rod 16 to move to the feathered position. The control unit 11 can be equipped with the time delay relay 61.

[0109] By default, the control mechanism 14 is, for example, in the propulsion position. In the propulsion position, the moving part 56 can be either in the deployed position or in the retracted position depending on the setting of the actuator 41. Preferably, the moving part 56 is deployed in the propulsion position and the actuator 41 is not electrically powered.

[0110] Following this embodiment, in the active state, the time-delay relay 61 allows the actuator 41 to be energized, enabling it to move to the retracted position of the moving part 56 to move the control rod 16 to the feathered position. Advantageously, the blades 6 of all the propellers 2 are feathered by command from the control unit 11 without distinction. Advantageously, the method includes a step of energizing the actuator 41 for a predetermined duration.

[0111] Conversely, in its resting state, the time-delay relay 61 does not supply power to the actuator 41, which occupies the extended position in which the control rod 16 is in the propulsion position. Of course, both the time-delay relay 61 and the actuator 41 can be programmed to operate differently and in reverse.

[0112] The time-delay relay 61 is configured to maintain its active state for a predetermined period during which the actuator 40 is electrically powered. In this way, the actuator 41 maintains and locks the preferred feathering position for a predetermined period while the actuator is powered by the power supply 42. The predetermined period can be a few seconds, for example, less than 10 seconds. Once the power supply is switched off, the actuator 41 retains the position (this irreversible nature will be specified later in the description). In other words, the method includes a step of holding the feathering position.

[0113] Following an alternative operating mode, the actuator 41 can switch from one position to the other (active and inactive) in response to a command from the cockpit, for example, from the pilot. The pilot can order feathering based on parameters displayed in the cockpit that are related to the operating status of the electric motor 10 or other components or environmental conditions. Environmental conditions other than the electric motor status could include a particular flight situation (degraded or not), excessive vibration, an anomaly in the electrical core, etc.

[0114] A control button P is, for example, electrically connected to the time-delay relay 61 and can be manually activated. The control button P is located, for example, in the aircraft, preferably in the aircraft cockpit, for this purpose. Activating the control button P advantageously, but not exclusively, allows the state of the time-delay relay 61 to be controlled, which in this case will activate the power supply to the actuator 41 for a predetermined duration. This mode of operation is particularly advantageous in the event of a failure of the connection between the electric motor 10 and the control unit 11, or a failure of the control unit 11. Regardless of the origin of the control command, the signal advantageously, but not exclusively, passes through a time-delay relay 61, which maintains the power supply to the actuator 41 for a predetermined or calibrated duration, thus controlling the movement of the control rod 16 in one direction or the other.The command order allows the feathering of the blades of all 2 propellers.

[0115] Advantageously, but not exclusively, the actuator 41 includes a torque limiter configured to disengage the moving part 56 after it has moved to a retracted or extended position. For example, the torque limiter restricts the maximum force transmitted through the control rod 16 when it (or the control ring 15) comes to rest against a stop (called the end stop). In other words, the actuator 41 is irreversible. This irreversibility is advantageously inherent to the actuator 41.

[0116] In other words, we understand that the actuator includes a disengageable movable part connected to the control rod which is configured to occupy a deployed or retracted position in which an electric motor of the actuator and means for moving the movable part are disconnected allowing the position of the control rod, and preferably the position of the blades, here the feathering position or the propulsion position.

[0117] In this description, the term "irreversible" refers to the fact that once the moving part has been moved to one of its retracted and extended positions, it cannot return to its other position. Advantageously, the position is maintained fixed regardless of any external forces applied to the control rod 16. Advantageously, but not exclusively, the disengagement is only effective for a limited time and when the control ring 15 is in contact with one of the two mechanical stops (described later) to prevent excessive engine torque and therefore overheating.

[0118] In particular, the control rod 16 extends until the control ring 15 bears against a first stop to limit the travel of the moving part 56 towards the feathering position. The first stop is advantageously supported by the hub 7. As soon as the control ring 15 reaches the first stop, the moving part 56 is mechanically and automatically disengaged. That is to say, there is no longer any transmission of motion between the electric motor of the actuator 41 and the movement mechanism of the moving part 56. Disengagement is advantageously achieved when a maximum torque (or force) is applied to the control rod 16 (the internal motor of the actuator generates the maximum torque).After the predetermined time elapses allowing the actuator 41 to be powered, the actuator 41 maintains its feathered position because there is no longer a mechanical connection between the moving part and the electric motor of the actuator 41, and because the actuator 41 is irreversible. Such a system is simple to implement, efficient, and eliminates the need for, for example, electrical limit switches, which require careful adjustment and are prone to failure.

[0119] Conversely, the control rod 16 retracts or moves back until the control ring 15 is against a second stop to limit the travel of the moving part 56 towards the propulsion position.

[0120] The first stop is advantageously supported by the hub 7. As soon as the control ring 15 reaches the second stop, the moving part 56 is also disengaged mechanically and automatically. As with the feathering operation, disengagement is advantageously achieved here when a maximum torque (or force) is applied to the control rod 16. The actuator 41 maintains the propulsion position because there is no longer a mechanical connection between the moving part 56 and the electric motor 10 of the actuator 41, and because the actuator 41 is irreversible.

[0121] Figure 10 shows the extreme working position of the propeller blades 6. In this position, the blades 6 are arranged to allow the aircraft to move forward, i.e., the propulsion or "flight pitch" position. The feathering device 40 is not activated; that is, the actuator 41 is not electrically powered and the moving part 56 of the actuator 41 is deployed.

[0122] In this position, the control ring 15 bears against the second stop, which limits the stroke of the moving part 56. Advantageously, but not exclusively, the second stop is formed by the cover 28. For example, the cover 28 bears against the adjustment part 70. In this example, the adjustment part 70 allows the position of at least the control rod 16 to be adjusted. The adjustment part 70 is, for example, a screw mounted on a cover 71 and extending along the longitudinal axis X. The screw is tightened more or less depending on the desired stroke. Such a system is relatively simple, functional, compact, and does not affect the drag of the propulsion assembly 1. In this embodiment, the cover 71 is attached to the hub 7. The cover 71 comprises for this purpose a cylindrical wall 72b, with axis centered on the longitudinal axis X, which is fixed to the upstream wall 7a of the hub 7 via fixing members 73.The cover 71 includes, for example, a base 72a from which the cylindrical wall 72b extends. The base 72a is perpendicular to the longitudinal axis X. The adjusting element 70 (here the screw) is supported by the base 72a. The cover 71 is preferably mounted upstream of the hood 28. The cover 71 is advantageously, but not exclusively, positioned opposite the control ring 15. A flexible space 74 is formed between the cover 71 and the control ring 15, which supports the hood 28.

[0123] Advantageously, but not exclusively, the feathering device includes an elastic return element 75 which is mounted in the propulsion assembly 1 and which is capable of acting on the control mechanism 14 so as to force the control mechanism 14 (and the control rod 16) to move to a feathering position of the blades in the event of failure of the actuator 41. In the present example, the elastic return element 75 includes a return spring 76, and preferably a compression spring. Preferably, this involves a single return spring 76. This spring extends along the longitudinal axis X and is housed at least partially in a recess 77 of the control ring 15. The recess 77 is annular and centered on the longitudinal axis X. In other words, the return spring 76 is rotationally fixed to the control ring 15. Advantageously, the return spring 76 is fixed because it is highly compressed.One of the walls of the housing 77 is formed by the first wall 29 of the control ring 15. The return spring 76 is partly guided in the housing 77.

[0124] The return spring 76 advantageously extends between a first end 76a and a second end 76b. The return spring 76, located in the hub 7, and preferably in the space 74, is, for example, compressed in the propeller position of the blades (extreme working position of the blades) to propel the aircraft. The space 74 is preferably free of lubricant.

[0125] The return spring 76 bears axially against the control ring 15 and exerts a force on it. The first end 76a bears against the base 72a of the cover 71. The cover 71 includes, for example, a groove 79, centered on the longitudinal axis, formed in the base 72a and intended to house the first end 76a of the return spring 76. The second end 76b bears, for example, against the control ring 15 (and preferably against the base 78 of the annular housing 77).

[0126] Advantageously, but not exclusively, the return spring 76 surrounds the hood 28. This configuration makes it easier to mount the return spring 76 and the hood 28 because the latter serves as a stop for adjusting the propulsion position "no flight" via the adjustment element 70.

[0127] Advantageously, the return spring 76 is permanently in contact with the control ring 15 in both extreme positions.

[0128] Figure 11 shows the extreme feathering position. In this position, the blade chord is substantially parallel to the longitudinal axis (+ / - 10%). The actuator 41 is powered by the electrical supply, and the moving part 56 is in its retracted position. The return spring 76, which is relaxed in this state, is still axially supported against the control ring 15 and in contact with the cover 71. The cover 28 is also at a distance from the adjusting part 70.

[0129] As can be seen in Figure 11, the control ring 15 bears against the first stop. The first stop is formed here by the ferrule 12. Preferably, the control ring 15 bears against the first axial portion 12a of the ferrule 12, which is fixed to the hub 7.

[0130] To move from the extreme working position (propulsion position) to the extreme feathering position, the movable member 56 exerts a pulling force on the control rod 16 (after a power command from the actuator 41), which causes the rod and the control ring 15 to translate. The translational movement of the control ring 15 affects the position of the blades. The control rod 16 is fixed against rotation, while the control ring 15 rotates with the propeller hub 7.

[0131] The elastic potential energy of the compressed return spring 76 is used to assist the movement of the control ring 15 and to move from the propulsion position to the feathering position of the blades, when the actuator 41 moves from the inactive to the active position, in particular when the moving part 56 is retracted. The spring 76 can also return the control mechanism 14 to the feathering position in the event of failure of the actuator 41 or the control rod 16 (breakage of the control rod 16 for example).

Claims

DEMANDS 1. Aircraft propulsion assembly (1) comprising: - a propeller (2), with a longitudinal axis (X), equipped with blades (6) with a variable pitch angle, - an electric motor (10) for rotating the propeller (2) and electrically controlled by a control unit (11) arranged in the propulsion assembly or in the aircraft, - a control mechanism (14) for the blade pitch angle, located in a hub (7) of the propeller (2), which can be moved in translation along the longitudinal axis (X) between a feathering position and a propulsion position corresponding to a blade angle adapted to the propulsion of the aircraft, and - a control rod (16) for the movement of the mechanism (14), which is fixedly connected in translation to the control mechanism (14) and which passes axially through the electric motor (10) to present a downstream end (16b) disposed on the side opposite the propeller (2) with respect to the electric motor (10), characterized in that the assembly includes a feathering device (40) equipped with an actuator (41) which is connected to a downstream end (16b) of the control rod (16), the actuator (41) being configured so as to move the control rod (16) and the control mechanism (14) towards the feathering position in response to a command from the control unit (11) relating to a state of the electric motor (10) and to maintain the feathering position by means of at least one disengageable element of the actuator (41).

2. Propulsion assembly (1) according to claim 1, characterized in that the control mechanism (14) comprises a control ring (15) centered on the longitudinal axis (X) and connected to the blades (6) of the propeller via linkage elements, the control ring (15) being driven in rotation by the hub (7) of the propeller.

3. Propulsion assembly (1) according to one of claims 1 and 2, characterized in that the actuator (41) is mounted on a chassis (43) which is fixed to a housing of the electric motor (10).

4. Propulsion assembly (1) according to claim 3, characterized in that the feathering device (40) comprises a connecting rod (58) which is articulated on one side, at the downstream end (16b) of the control rod (16) and on the other hand, on a movable part (56) of the actuator (41).

5. Propulsion assembly (1) according to claim 4, characterized in that the connecting rod (58) has a length measured between a first end (58a) and a second end (58b), the movable member (56) of the actuator (41) being connected at the center of the length of the connecting rod (58), the first end (58a) of the connecting rod (58) being articulated to the downstream end (16b) of the control rod (16) and the second end (58b) of the connecting rod (58) being articulated on the chassis (43).

6. Propulsion assembly (1) according to any one of claims 1 to 5, characterized in that the actuator (41) maintains the feathering position after the elapsed time predetermined during which the actuator (41) is powered by an electrical power source (42) installed in the propulsion assembly or in the aircraft.

7. Propulsion assembly (1) according to any one of claims 1 to 6, characterized in that it comprises a time-delay relay (61) connected to the control unit (11) and capable of occupying, in response to a command from the control unit (11), an active state allowing the actuator (41) to switch to a position to move the control rod (16) into the feathering position.

8. Assembly according to any one of claims 1 to 6, characterized in that it comprises a time-delay relay (61) electrically connected to a manually activatable control button (P) and capable of occupying, in response to the activation of the control button (P), an active state allowing the actuator (41) to switch to a position to move the control rod (16) into the feathering position, the control button being arranged in the aircraft.

9. Propulsion assembly (1) according to any one of claims 4 to 8, characterized in that the control ring (15) is supported against a first stop to limit the stroke of the moving member (56) in the feathering position or is supported against a second stop to limit the stroke of the moving member (56) in the propulsion position.

10. Propulsion assembly (1) according to any one of claims 4 to 7, characterized in that the actuator (41) comprises a torque limiter which is configured to disengage the moving part (56) after the latter has been moved into a retracted position or into a deployed position.

11. Propulsion assembly (1) according to any one of the preceding claims, characterized in that a return spring (76) located in the hub (7) of the propeller is able to act on the control mechanism (14) so ​​as to force the control mechanism (14) to move to a feathering position of the blades in the event of failure of the actuator (41).

12. Propulsion assembly (1) according to the preceding claim, characterized in that the return spring (76) is mounted rotationally fixed with the control ring (15), the control rod (16) having an upstream part (17) passing through the control ring (15) and which rotates relative to the upstream part (17) via bearings (19a, 19b).

13. Propulsion assembly (1) according to the preceding claim, characterized in that the bearing supports (19a, 19b) comprise an upstream bearing (19a) with radial bearing and a downstream bearing (19b) with axial bearing, the upstream bearing (19a) comprising an inner ring (20a) attached to the upstream part (17) of the control rod (16) and an outer ring (20b) attached to the control ring (15), the downstream bearing (19b) comprising an upstream ring (23a) attached to the control ring (15) and a downstream ring (23a) attached to the upstream part (17) of the control rod (16).

14. Aircraft wing (4) comprising at least one propulsion assembly (1) according to any one of the preceding claims.

15. Aircraft comprising an aircraft wing (4) according to the preceding claim or a propulsion assembly (1) according to any one of claims 1 to 13.

16. Method for feathering a propulsion assembly according to any one of claims 1 to 13, the method comprising a step of moving the control rod (16) and the control mechanism (14) in translation according to a predetermined state of the electric motor (10) so as to drive the propeller blades into a feathered position and a step of maintaining the feathered position.

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