Aerial propulsion system

Abstract

An aviation propulsion system (1) is disclosed, comprising: a fan rotor (9) comprising variable pitch blades (19); a control system (300) configured to control the pitch of the blades, in particular to control the feathering of the blades (19); and a brake (200) configured to block rotation of the fan rotor (9) in accordance with feathering control of the blades (19).

Description

Technical Field

[0001] The present disclosure relates generally to the field of propulsion systems, and more particularly to aviation propulsion systems including ducted or unducted fans. Background Art

[0002] The propulsion system generally includes, from upstream to downstream along the direction of gas flow, a fan section, a compressor section, a combustor, and a turbine section. The compressor section may include a low-pressure compressor and a high-pressure compressor, and the turbine section may specifically include a high-pressure turbine and a low-pressure turbine. The high-pressure compressor is rotationally driven by the high-pressure turbine via a high-pressure shaft. The fan and the low-pressure compressor (where appropriate) are rotationally driven by the low-pressure turbine via a low-pressure shaft.

[0003] Technological research has significantly improved the environmental performance of aircraft. The applicant has taken these factors into account at all design and development stages in order to obtain aviation components and substances that consume less energy, are more environmentally friendly, and have a moderate impact on the environment when integrated and used in civil aviation, with the aim of improving the energy efficiency of these aircraft.

[0004] In particular for ground safety reasons, systems for locking fan rotors have been proposed, for example in FR 3075862. However, these known systems are generally complex, bulky and heavy. Summary of the Invention

[0005] It is an object of the present disclosure to provide a system for locking a fan rotor that is simpler, lighter, and / or more compact than prior art systems.

[0006] To this end, an aviation propulsion system is provided, which includes: a fan rotor including variable-pitch blades; a control system configured to control the pitch of the blades, in particular to control the feathering of the blades; and a brake configured to lock the rotation of the fan rotor in response to a command to feather the blades.

[0007] Thus, the brake is activated when the fan rotor blades are feathered. This eliminates the need for a dedicated control system for the brake, increasing the versatility of the control system: this saves space and mass, and simplifies the system. Furthermore, where appropriate, it is possible to dispense with the low-speed lubrication system of the reducer, located between the low-pressure shaft and the fan shaft, since the brake locks the rotation and renders such lubrication unnecessary.

[0008] As far as technically feasible, the aviation propulsion system may further include the following optional features, taken alone or in combination with one another.

[0009] Optionally, the aircraft propulsion system comprises a delay timer configured to delay rotational locking by the brake relative to feathering of the blades by the control system.

[0010] Optionally, the brake is configured to unlock rotation of the fan rotor in response to a command from the control system to unfeather the blades.

[0011] Optionally, the aircraft propulsion system includes a delay timer configured to delay un-feathering of the blades by the control system relative to unlocking of rotation of the fan rotor by the brake.

[0012] Optionally, the aircraft propulsion system includes a drive shaft, wherein the brake is configured to disengage when the rotational speed of the drive shaft increases and exceeds a threshold disengagement speed, the threshold disengagement speed being, for example, between 50 rpm and 800 rpm, for example, between 50 rpm and 400 rpm, for example, between 100 rpm and 300 rpm.

[0013] Optionally, the aircraft propulsion system includes a drive shaft, wherein the brake is configured to engage when the rotational speed of the drive shaft decreases and becomes less than a threshold engagement speed, the threshold engagement speed being, for example, between 50 rpm and 800 rpm, for example, between 50 rpm and 400 rpm, for example, between 100 rpm and 300 rpm.

[0014] Optionally, the aircraft propulsion system comprises a fuse for mechanically isolating the brake from the rest of the system.

[0015] Optionally, the brake is configured to be actuated by energy that also causes a change in the pitch of the blades.

[0016] Optionally, the control system comprises a hydraulic circuit connected to the brake, and the energy is hydraulic energy delivered by the hydraulic circuit.

[0017] Optionally, the aircraft propulsion system includes: a drive shaft; a fan shaft adapted to rotationally drive a fan rotor; and a speed reducer rotationally coupling the drive shaft and the fan shaft and configured to drive the fan shaft at a rotational speed less than that of the drive shaft. Accordingly, the speed reducer includes: a sun gear having a diameter and rotationally coupled to the drive shaft; a satellite meshing with the sun gear; and a ring gear having a diameter and meshing with the satellite, the diameter of the ring gear being greater than the diameter of the sun gear. A brake is configured to lock the rotation of the sun gear, the satellite, the ring gear, the drive shaft, or the fan shaft.

[0018] Optionally, the brake is configured to lock rotation of the sun gear or the satellites.

[0019] Optionally, the aircraft propulsion system includes a lubrication device, the lubrication device includes a pump, the pump includes a pump rotor and is configured to supply oil to the speed reducer when the pump rotor rotates, wherein the brake is configured to interact with the pump rotor.

[0020] Optionally, control of the brake is dependent on at least one operating state of the lubrication device.

[0021] Optionally, the brake is hydraulically controlled, the hydraulic control device being fluidly connected to the lubrication device.

[0022] Optionally, the threshold disengagement speed is equal to the threshold engagement speed, and the system includes a clutch configured to rotationally disengage the pump rotor from the sun gear, satellite gears, ring gear, fan shaft, or drive shaft if the rotational speed of the drive shaft is greater than or equal to the threshold engagement speed, and to rotationally couple the pump rotor to the sun gear, satellite gears, ring gear, fan shaft, or drive shaft if the rotational speed of the drive shaft is less than the threshold engagement speed.

[0023] Optionally, the lubrication device includes a second pump that is different from the pump including the pump rotor, the second pump being configured to supply oil to the speed reducer when the rotational speed of the drive shaft is greater than or equal to a threshold engagement speed.

[0024] Alternatively, the brake comprises only a valve system comprising a first control valve located downstream of the pump and a second control valve located upstream of the pump.

[0025] Optionally, the brake comprises a mechanical brake.

[0026] Optionally, the brake comprises a valve system comprising a first control valve located downstream of the pump and a second control valve located upstream of the pump.

[0027] Optionally, the speed reducer comprises a planet carrier on which the satellite part is rotatably mounted, and the planet carrier is fixed relative to the stator of the propulsion system.

[0028] Optionally, the aircraft propulsion system extends in an axial direction, taking into account that in the axial direction the speed reducer is located between the pump and the drive shaft.

[0029] Optionally, the aircraft propulsion system extends in an axial direction and further comprises a supply conduit for supplying oil to the pump, wherein the supply conduit axially crosses the speed reducer.

[0030] Optionally, the reducer includes a plurality of satellite parts, the lubrication device includes a plurality of pumps, each pump includes a pump rotor, the plurality of pumps includes at least two pumps and at most as many pumps as the satellite parts, each pump rotor is rotationally coupled to a different satellite part, and the lubrication device is configured to lubricate the reducer with oil when the pump rotor rotates.

[0031] A method for braking a fan rotor of a propulsion system is also provided, the method comprising locking rotation of a fan rotor including variable pitch blades based on feathering of the blades.

[0032] Optionally, locking is performed after feathering the blades.

[0033] Optionally, un-feathering of the blades is accomplished after unlocking the fan rotor. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Other features, objects and advantages will appear from the following description which is merely illustrative and non-limiting and which should be read with reference to the accompanying drawings, in which:

[0035] - Figure 1 schematically illustrates an aircraft including a propulsion system,

[0036] - Figure 2 An example of a propulsion system having a ducted fan section is schematically shown in partial cross-section.

[0037] - Figure 3 An example of a propulsion system having an unducted fan section is schematically shown in partial cross-section.

[0038] - Figure 4 schematically shows an example of a speed reduction mechanism in a first variation,

[0039] - Figure 5 Schematically shows an example of a speed reduction mechanism in a second variation,

[0040] - Figure 6 Schematically showing an example of a speed reduction mechanism and a lubrication device according to a first embodiment,

[0041] - Figure 7 Schematically showing an example of a speed reduction mechanism and a lubrication device according to a second embodiment,

[0042] - Figure 8 Schematically showing an example of a speed reduction mechanism and a lubrication device according to a third embodiment,

[0043] - Figure 9 Schematically showing an example of a speed reduction mechanism and a brake according to a first embodiment,

[0044] - Figure 10 Schematically showing an example of a speed reduction mechanism and a brake according to a second embodiment,

[0045] - Figure 11 Schematically shows a brake according to an embodiment and certain components of a lubrication device according to an embodiment,

[0046] - Figure 12 is a diagram showing the operating area of ​​the pump as a function of the rotational speed of the drive shaft,

[0047] - Figure 13 Schematically shows an example of a deceleration mechanism, a brake, and a control system according to an embodiment,

[0048] - Figure 14 is a flow chart of the steps of the braking method,

[0049] - Figure 15 Including showing Figure 14 Flowchart of an embodiment of the steps of the method,

[0050] - Figure 16 Including showing Figure 14 Flowcharts of embodiments of further steps of the method,

[0051] In all figures, similar elements have the same reference numerals. DETAILED DESCRIPTION

[0052] Figure 1 An example of an aircraft 100 is shown. Aircraft 100 is an airplane comprising a fuselage 101 and two wings 102. In this example, the aircraft comprises two propulsion systems 1, each of which is attached to a respective wing 102 of aircraft 100 via a pylon. In another embodiment, the aircraft may comprise one or more propulsion systems attached to fuselage 101.

[0053] Figure 2 A first example of a propulsion system 1 is schematically shown in a partial cross-sectional view.

[0054] In this example, the propulsion system 1 is a gas turbine engine with twin bodies and a ducted fan.

[0055] exist Figure 2 , the propulsion system 1 has a main direction (or axial direction) extending along a longitudinal axis X. The propulsion system 1 comprises a fan section 2 and a body 3 generally called a "gas generator".

[0056] The fan section 2 includes a fan 22 and a fan housing 12. The fan 22 includes a fan rotor 9. The fan housing 12 surrounds the fan rotor 9. The fan rotor 9 is rotatably mounted relative to the fan housing 12.

[0057] The fan rotor 9 includes a fan hub 13 and fan blades 14 extending radially from the hub 13. The fan blades 14 can be fixed relative to the fan hub 13 or have a variable pitch. In the latter case, each of the fan blades 14 can be rotatably mounted relative to the fan hub 13 along a set axis and connected to a pitch changing mechanism 15 installed in the propulsion system 1. The pitch changing mechanism 15 makes it possible to adjust the pitch angle of the fan blades 14 according to the flight phase.

[0058] Pitch changing mechanism 15 is specifically capable of "feathering" fan blades 14. In a manner known per se, when the fan blades are feathered, the drag generated by fan rotor 9 is minimized. In other words, the feathered position of the fan blades is the position that minimizes the maximum cross-section of the fan, or minimizes the fan's drag relative to the air flow across the fan. In practice, when fan blades 14 are feathered, the pitch angle of fan blades 14 is approximately 90°.

[0059] When the pitch changing mechanism is not controlled, such as when the propulsion system is shut down, for example, the pitch changing mechanism 15 is configured to keep the fan blades feathered. This default position can be obtained by appropriate return means, such as a spring.

[0060] The fan rotor 9 comprises at least fourteen fan blades 14 and at most twenty-four blades 14 , for example at least sixteen fan blades 14 and at most twenty-two fan blades 14 .

[0061] In this example, fan section 2 also includes a fan stator 16 fixedly mounted on fan housing 12. Fan stator 16 includes fixed blades 17, commonly known as outlet guide vanes (OGVs). This fixed blade assembly has the following functions: straightening and regulating the air flow downstream of fan rotor 9 to optimize engine thrust. This fixed blade assembly also serves to reduce noise 19.

[0062] Alternatively, the outlet vanes 17 may have a variable pitch. Where appropriate, similar to the fan blades 14 of the fan rotor 9, the root of each of the outlet vanes 17 may be pivotally mounted along a set axis and connected to a pitch changing mechanism (not shown), by which the pitch is adjusted according to the flight phase.

[0063] The number of outlet vanes 17 depends on the acoustic standards defined for the propulsion system 1 and is at least equal to the number of fan blades 14 .

[0064] The main body 3 includes a compressor section 29 , a combustion chamber 6 , and a turbine section 30 .

[0065] The compressor section 29 includes a low-pressure compressor 4 and a high-pressure compressor 5 .

[0066] The low-pressure compressor 4 comprises a rotor 41 adapted to be driven in rotation relative to the housing 31 of the propulsion system 1 , and a stator 42 fixedly mounted on the housing 31 .

[0067] The rotor 41 of the low-pressure compressor 4 includes a movable wheel 4a, and the stator 42 of the low-pressure compressor 4 includes a fixed wheel 4b. The movable wheels 4a and the fixed wheels 4b are arranged alternately to form a series of low-pressure compressor stages.

[0068] Similarly, the high-pressure compressor 5 comprises a rotor 51 adapted to be driven in rotation relative to the housing 31 of the propulsion system 1 , and a stator 52 fixedly mounted on the housing 31 .

[0069] The rotor 51 of the high-pressure compressor 5 includes movable wheels 5a, and the stator 52 of the high-pressure compressor 5 includes fixed wheels 5b. The movable wheels 5a and the fixed wheels 5b are arranged alternately to form a series of high-pressure compressor stages.

[0070] The turbine section 30 may include a high-pressure turbine 7 and a low-pressure turbine 8 .

[0071] The high-pressure turbine 7 comprises a rotor 71 adapted to be driven in rotation relative to the housing 31 of the propulsion system 1 and a stator 72 fixedly mounted on the housing 31 .

[0072] The rotor 71 of the high-pressure turbine 7 includes movable wheels 7a, and the stator 72 of the high-pressure turbine 7 includes fixed wheels 7b. The movable wheels 7a and the fixed wheels 7b are arranged alternately to form a series of high-pressure turbine stages.

[0073] Similarly, the low-pressure turbine 8 comprises a rotor 81 adapted to be driven in rotation relative to the housing 31 of the propulsion system 1 , and a stator 82 fixedly mounted on the housing 31 .

[0074] The rotor 81 of the low-pressure turbine 8 includes movable wheels 8a, and the stator 82 of the low-pressure turbine 8 includes fixed wheels 8b. The movable wheels 8a and the fixed wheels 8b are arranged alternately to form a series of low-pressure turbine stages.

[0075] The propulsion system 1 comprises a low-pressure shaft 11 connecting the rotor 81 of the low-pressure turbine 8 to the rotor 41 of the low-pressure compressor 4 , the low-pressure shaft 11 being mounted rotatably about a longitudinal axis X relative to the casing 31 .

[0076] When the propulsion system 1 is in operation, the rotor 81 of the low-pressure turbine 8 rotationally drives the rotor 41 of the low-pressure compressor 4 via the low-pressure shaft 11 .

[0077] Propulsion system 1 also includes a fan shaft 20 and a reduction gear 19. Fan rotor 9 is fixedly mounted on fan shaft 20. Reduction gear 19 has an input and an output. The input of reduction gear 19 is connected to low-pressure shaft 11, and the output of reduction gear 19 is connected to fan shaft 20. Therefore, when propulsion system 1 is operating, rotor 81 of low-pressure turbine 8 not only rotationally drives rotor 41 of low-pressure compressor 4, but also rotationally drives fan rotor 9 via low-pressure shaft 11, reduction gear 19, and fan shaft 20.

[0078] Due to the speed reduction mechanism 19 , the fan rotor 9 is rotationally driven at a speed lower than the rotation speed of the rotor 41 of the low-pressure turbine 4 .

[0079] The reduction mechanism 19 thus makes it possible to independently optimize the rotational speed of the fan 22 and the rotational speeds of the low-pressure turbine 8 and the low-pressure compressor 4 .

[0080] The low-pressure turbine 8 , the low-pressure shaft 11 , the low-pressure compressor 4 , the fan shaft 20 , the speed reduction mechanism 19 and the fan 22 together form a “low-pressure body” of the propulsion system 1 .

[0081] The propulsion system 1 further comprises a high-pressure shaft 10 connecting the rotor 71 of the high-pressure turbine 7 to the rotor 51 of the high-pressure compressor 5 , the high-pressure shaft 10 being mounted rotatably relative to the casing 31 about a longitudinal axis X. The high-pressure shaft 10 is coaxial with the low-pressure shaft 11 and extends around the low-pressure shaft 11 .

[0082] When the propulsion system 1 is in operation, the rotor 71 of the high-pressure turbine 7 rotationally drives the rotor 51 of the low-pressure compressor 5 via the low-pressure shaft 11 .

[0083] The high-pressure turbine 7 , the high-pressure shaft 10 and the high-pressure compressor 4 together form the “high-pressure body” of the propulsion system 1 .

[0084] The low-pressure shaft 11 and the high-pressure shaft 10 may be co-rotating, ie driven in the same direction of rotation about the longitudinal axis X. In a variant, the low-pressure shaft 11 and the high-pressure shaft 10 may be counter-rotating, ie driven in opposite directions of rotation about the longitudinal axis X.

[0085] The twin-body propulsion system 1 may in particular comprise a single-stage high-pressure turbine 7 (ie comprising exactly one stage) or a two-stage high-pressure turbine 7 (ie comprising exactly two stages (eg Figure 2 as shown in the example)).

[0086] The high pressure compressor 5 comprises at least eight stages (e.g. Figure 2 ) and up to eleven levels.

[0087] The low-pressure turbine 8 comprises at least three stages (e.g. Figure 2 ) and up to five levels.

[0088] The low-pressure compressor 4 includes at least two stages and at most four stages.

[0089] When the propulsion system is operating, the air flow F entering the propulsion system 1 crosses the fan 22 and is then divided into a primary air flow F1 and a secondary air flow F2 , which circulate through the propulsion system 1 from upstream to downstream.

[0090] A secondary air flow F2 (also called "bypass air flow") flows through a secondary air path around the body 3. The secondary air flow F2 enables cooling of the periphery of the body 3 and serves to generate most of the thrust supplied by the propulsion system 1 .

[0091] The main air flow F1 flows through the air path within the main body 3, thereby passing through the compressor section 29 (low-pressure compressor 4 and high-pressure compressor 5), the combustion chamber 6, and the turbine section 30 (high-pressure turbine 7 and low-pressure turbine 8). In the combustion chamber 6, the main air flow F1 is mixed with fuel to be used as a combustion product. The main air flow F1 flows through the turbine section 30, which receives energy from the combustion chamber 6. This causes the movable wheels 7a and 8a of the turbine section 30 to rotate. The rotation of the movable wheels 7a and 8a of the turbine section 30 in turn rotationally drives the compressor section 29 and the movable wheels 4a and 5a of the fan rotor 9.

[0092] In order to improve the propulsion efficiency of the propulsion system 1 and reduce the specific fuel consumption of the propulsion system 1 and the noise emitted by the fan section 2, the propulsion system 1 has a high bypass ratio. The term "high" bypass ratio refers to a bypass ratio greater than or equal to 10, for example, a bypass ratio between 10 and 18 (inclusive). The bypass ratio is defined as the ratio of the mass flow rate of the secondary air flow F2 to the mass flow rate of the primary air flow F1, with these mass flows of the secondary air flow F2 and the primary air flow F1 measured when the propulsion system 1 is at rest, not installed, at takeoff rating, standard atmospheric pressure (as defined by the 3rd edition of the International Civil Aviation Organization (OACI) Manual, Document 7488 / 3) and at sea level. The term "not installed" means that the measurements are taken when the propulsion system 1 is on a test bench (and not installed on an aircraft), at which time the measurements are easier to perform.

[0093] In the propulsion system, a circuit such as a Figure 2The reduction mechanism 19 shown enables the rotational speed and pressure ratio of the fan rotor 9 to be reduced while increasing the power extracted by the low-pressure turbine 8. Specifically, the overall efficiency of the propulsion system 1 is the propulsive efficiency in first-order terms, which favorably influences propulsive efficiency by minimizing the change in kinetic energy of the air passing through the propulsion system 1. In a propulsion system with a high bypass ratio, the majority of the flow that generates propulsion is formed by the secondary air flow F2 of the propulsion system 1, the kinetic energy of the secondary air flow F2 being primarily influenced by the compression experienced by the secondary air flow F2 during its passage through the fan section 2. Therefore, propulsive efficiency and the pressure ratio of the fan section 2 are related: the lower the pressure ratio of the fan section 2, the higher the propulsive efficiency. To optimize the propulsive efficiency of the propulsion system 1, the fan pressure ratio (corresponding to the ratio between the average pressure at the outlet of the fan stator 16 (or, in the absence of any stator 16, 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, and for example, between 0.90 and 1.45. Here, the average pressure is measured along the height of at least one of the fan blades 14 , ie along the surface delimiting the flow path radially inwardly at the inlet of the fan rotor 9 at the tip 21 of the fan blade 14 .

[0094] Furthermore, the peripheral velocity at the tip 21 of the fan blade 14 may be between 260 m / s (ms −1 ) and 400 m / s (ms −1 ), inclusive. The pressure ratio of the fan may be between 1.20 and 1.45.

[0095] In a direct drive propulsion system, the fan rotor 9 can alternatively be coupled directly to the low-pressure shaft 11, i.e. without any reduction mechanism. The low-pressure shaft 11 is colinear with the fan shaft 20, so that the fan rotor 9 driven by the low-pressure shaft 11 has the same rotational speed as the rotor 81 of the low-pressure turbine 8.

[0096] The propulsion system 1 is configured to supply a thrust between 18,000 lbf (80,068 N) and 51,000 lbf (226,859 N), for example, between 20,000 lbf (88,964 N) and 35,000 lbf (155,688 N).

[0097] The diameter D of the fan rotor 9 can be between 80 inches (203.2 cm) and 185 inches (469.9 cm), inclusive. When the fan rotor 9 is ducted, the diameter D is, for example, between 85 inches (215.9 cm) and 120 inches (304.8 cm), inclusive, such as approximately 90 inches (228.6 cm), which enables conventional integration of the propulsion system 1, particularly under the wing of the aircraft 1.

[0098] Figure 3 A second example of a propulsion system 1 is schematically shown in a partial cross-sectional view.

[0099] exist Figure 3 In, with Figure 2 Identical or similar components of the propulsion system are denoted by the same reference numerals.

[0100] exist Figure 3 In the example shown, the propulsion system 1 is a gas turbine engine with a twin body and an unducted fan. The gas turbine engine may be of the open rotor or unducted single fan type.

[0101] and Figure 2 Unlike the first example, the fan rotor 9 , which may also be indicated by the term “propeller”, is not surrounded by a fan casing.

[0102] The fan section 2 is of the unducted type, and the fan blades 14 have variable pitch.

[0103] Alternatively, the propulsion system 1 may include two unducted, counter-rotating fan rotors 9. This type of propulsion system 1 is referred to as a "Contra-Rotating Open Rotor (CROR)" or "Unducted Double Fan (UDF)." The fan rotors 9 may be positioned at the rear of the main body 3 to form a push-type configuration, or at the front of the main body 3 to form a pull-type configuration.

[0104] The absence of any ducting around the fan rotor 9 makes it possible to significantly increase the bypass ratio without the propulsion system 1 being adversely affected by the mass of the casing 12 or nacelle intended to surround the fan section 2. Consequently, the bypass ratio of the propulsion system 1 including the unducted fan section 2 is greater than or equal to 40, for example, between 40 and 80 (inclusive). Furthermore, the peripheral speed at the tip 21 of the fan blades 14 of one or more fan rotors 9 may be between 210 m / s (ms-1) and 260 m / s (ms-1) (inclusive). The pressure ratio of the fan may be, for example, between 0.90 and 1.20 (inclusive).

[0105] The diameter D of the fan rotor 9 may be between 80 inches (203.2 cm) and 185 inches (469.9 cm), inclusive. When the rotor 9 is unducted, 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 in a plane perpendicular to the longitudinal axis X (i.e., the axis of rotation of the fan rotor 9) at the intersection between the tip 21 and the leading edge 22 of the fan blade 14.

[0106] Notice, Figure 2 and Figure 3 This is a partial view, diameter D is only partially visible.

[0107] The reduction mechanism 19 may comprise a single-stage or two-stage reduction mechanism, in this example a reduction mechanism with an epicyclic gear train, for example an “epicyclic” or “planetary” reduction mechanism according to the terms sometimes encountered by those skilled in the art.

[0108] For example, Figure 4 A first variant of a planetary reduction mechanism 19 is shown. The reduction mechanism 19 comprises a sun gear 19a (the input of the reduction mechanism 19), a ring gear 19b (the output of the reduction mechanism 19), and a series of satellites (satellite wheels) 19c. The sun gear 19a is centered on the axis of rotation of the reduction mechanism 19 (generally colinear with the longitudinal axis X) and is configured to be rotationally driven by the low-pressure shaft 11. The ring gear 19b is coaxial with the sun gear 19a and is configured to rotationally drive the fan shaft 20 about its axis of rotation X. A series of satellites 19c are circumferentially distributed between the sun gear 19a and the ring gear 19b about the axis of rotation X of the rotor 9 of the fan section 2, each satellite 19c meshing internally with the sun gear 19a and externally with the ring gear 19b. The series of satellites 19c are mounted on a planet carrier 19d, which is fixed relative to a stator portion 19e of the propulsion system 1, for example, relative to the housings of the compressor sections 4 and 5. In both variants, the diameter of the ring gear 19b is greater than the diameter of the sun gear 19a.

[0109] In another example, Figure 5 Shown according to the planetary formula ( Figure 4 ) of a second variant of the reduction gear mechanism 19, in which case the ring gear 19b is fixedly mounted on the stator part 19e of the propulsion system 1 and the fan shaft 20 is rotationally driven by the planetary carrier 19d (therefore, the planetary carrier 19d can rotationally move relative to the stator part 19e of the propulsion system 1, for example, rotationally move relative to the casing of the compressor sections 4, 5).

[0110] Regardless of the configuration of the speed reduction mechanism 19 , the diameters of the ring gear 19 b and the planetary carrier 19 d are larger than the diameter of the sun gear 19 a , so that the rotation speed of the fan rotor 9 is lower than the rotation speed of the low-pressure shaft 11 .

[0111] The reduction ratio of the reduction mechanism 19 is greater than or equal to 2.5 and less than or equal to 15. In the case of a propulsion system 1 including a ducted fan, the reduction ratio may be greater than or equal to 2.7 and less than or equal to 3.5, for example, approximately 3.0. In the case of a propulsion system 1 including an unducted fan, the reduction ratio may be between 9.0 and 11.0.

[0112] In order to optimize the performance of the propulsion system 1 , the propulsion system 1 includes all or some of the features described in detail below.

[0113] 1) Lubrication device for lubricating the reduction mechanism

[0114] The propulsion system 1 may include a lubrication device 100 having the function of lubricating all or part of the reduction mechanism 19. In the remainder of this disclosure, the reduction mechanism 19 will be more simply referred to as "reducer 19."

[0115] Figure 6 A first embodiment of this lubrication device 100 is shown, combined with a "planetary" reducer 19 as described above. Thus, the planet carrier 19d is fixed relative to the stator 19e of the propulsion system 1, while the sun gear 19a, the satellites 19c and the ring gear 19b can move in rotation. Moreover, in this configuration, the sun gear 19a forms the input of the reducer 19, which is connected to the drive shaft (for example, the low-pressure shaft as described above). The ring gear 19b is connected to the fan shaft 20. In this example, this "planetary" configuration makes it possible to simplify the structure of the lubrication device, resulting in a volume saving associated with easier integration.

[0116] The lubrication device 100 includes an oil inlet pipe 102 , a pump 104 , an oil supply pipe 106 and an oil distributor 108 .

[0117] The oil inlet conduit 102 fluidly connects an oil source (not shown) and a pump 104. The oil inlet conduit 102 supplies the pump 104 with oil from the oil source.

[0118] The oil inlet duct 102 axially crosses the reducer 19. More precisely, the oil inlet duct 102 passes between two adjacent satellites 19c of the reducer 19. This axial crossing helps to reduce the overall volume of the lubrication device 100 by utilizing the unoccupied space between the two adjacent satellites 19c. The space occupied in the engine is thus optimized.

[0119] In use, oil flows to the pump through the oil inlet conduit 102. In other words, the oil flows through the oil inlet conduit 102 in a direction towards the fan section.

[0120] An oil supply conduit 106 fluidly connects the pump 104 and the oil distributor 108 .

[0121] The oil distributor 108 forms the outlet of the lubrication device 100. The oil distributor is arranged to distribute the oil to the target components of the reducer 19 so that one or more components (sun gear 19a, satellites 19c, planet carrier, ring gear 19b, one or more bearings) are lubricated, and does so in an otherwise known manner.

[0122] The pump 104 has a function of supplying oil to the speed reducer 19. When the pump 104 is operating, the pump 104 pumps oil from the oil inlet pipe 102 and transmits the oil to the oil distributor 108 via the oil supply pipe 106. When the pump 104 is not operating, the pump 104 does not supply oil to the distributor 108.

[0123] Considering that, along the axial direction X, the speed reducer 19 is arranged between the pump 104 and the drive shaft 11. In other words, the pump 104 is upstream of the speed reducer 19 (if the direction refers to the flow direction of the air flow F when the propulsion system 1 is in operation). The pump 104 is surrounded by the fan shaft 20. This configuration allows for a saving in volume, as it utilizes space that is typically unused in the prior art, as this space is confined between the speed reducer and the fan shaft. The relative positioning of this space with respect to the speed reducer (and in particular with respect to the supply line) makes this operation quite counterintuitive.

[0124] The pump 104 includes a pump rotor that can rotate about its own axis, which is, for example, parallel to the axis X, in this example, colinear with the axis X. When the pump rotor is set to rotate, the pump 104 is in operation. When the pump rotor stops rotating, the pump 104 becomes inoperative.

[0125] The pump rotor is rotationally coupled to a rotating element of the reducer 19. This means that the rotating element in question is connected to the pump rotor via a mechanical coupling, which is adapted for the rotation of this element to drive the rotation of the pump rotor. The torque transmission line between the rotating element and the pump rotor is different from the torque transmission line between the low-pressure shaft 11 and the fan shaft 20 via the reducer 19. In this example, the rotating element is the sun gear 19a, in other words, the pump rotor is rotationally coupled to the sun gear 19a. The mechanical coupling connecting the sun gear 19a to the pump rotor does not comprise a satellite 19c or a ring gear 19b. This arrangement is not very space-consuming and, in particular, enables the use of space that was not occupied in the prior art.

[0126] Pump 104 is, for example, a bidirectional pump 104, i.e., it is configured to supply oil to reducer 19 when the pump rotor rotates in a first rotational direction or in a second, other rotational direction opposite to the first rotational direction. This allows lubrication of the reducer by pump 104 regardless of the direction of rotation of the fan rotor (and thus the pump rotor) caused by external forces when the engine is stopped (e.g., due to wind on the ground or in the event of propeller autorotation). Furthermore, this makes it possible to omit a non-return system to lock the fan rotor 9 from rotating in a direction opposite to the direction imparted by the turbine, which makes it possible to lighten the system and reduce the overall volume.

[0127] The pump 104 may be any type of pump: a piston pump 104 , a plate pump 104 , a centrifugal pump 104 , etc.

[0128] For example, the propulsion system includes a clutch 110. The clutch 110 is part of the aforementioned mechanical coupling, between the rotating element of the speed reducer 19 coupled to the pump rotor (in this example, the sun gear 19a) and the pump rotor.

[0129] The clutch 110 can be configured in two positions: an engaged position and a disengaged position.

[0130] In the engaged position, clutch 110 rotationally couples the pump rotor to the rotating element in question (here, sun gear 19a). In other words, when the clutch is in the engaged position, the pump rotor rotates if and only if the rotating element (here, sun gear 19a) rotates. When the clutch is in the engaged position, pump 104 is said to be in an engaged state.

[0131] In the disengaged position, the clutch 110 rotationally decouples the pump rotor from the rotating element in question (here, the sun gear 19a). In other words, the pump rotor is no longer mechanically connected to the rotating element, allowing the pump rotor to remain stationary while the rotating element rotates, and vice versa. When the clutch is in the disengaged position, the pump 104 can be said to be disengaged.

[0132] The clutch 110 is configured to switch from the engaged position to the disengaged position when the rotational speed of the drive shaft 11 increases and exceeds a threshold disengagement speed.

[0133] For example, the threshold disconnect speed is between 50 rpm and 800 rpm, or between 50 rpm and 400 rpm, or between 100 rpm and 300 rpm. When the pump 104 is an auxiliary pump supplementing the main pump, these speeds provide a compromise between the size of the pump 104 and the capacity of the main pump.

[0134] Furthermore, the clutch is configured so that when the rotation speed of the drive shaft 11 decreases and becomes less than the threshold engagement speed N Dfrom the disengaged position to the engaged position.

[0135] For example, the threshold engagement speed N D Between 50 rpm and 800 rpm, or such as between 50 rpm and 400 rpm, or such as between 100 rpm and 300 rpm. When the pump 104 is an auxiliary pump supplementing the main pump, these speeds provide a compromise between the size of the pump 104 and the capacity of the main pump.

[0136] The threshold disengagement speed may be related to the threshold engagement speed N D The same (which makes clutch 110 simpler), or it can be engaged with a threshold speed N D different.

[0137] If these two threshold speeds are the same, the clutch is configured to:

[0138] If the rotational speed of the drive shaft 11 is greater than or equal to the threshold engagement speed N D , the rotating element (here, the sun gear 19a) is rotationally separated, and

[0139] If the rotation speed of the drive shaft 11 is less than the threshold engagement speed N D , the pump rotor is rotationally coupled to the rotating element (here, the sun gear 19a).

[0140] Thus, the clutch 110 enables the pump 104 to be operated only at low speeds (startup, failure, maintenance, etc.). Such a clutch 110 enables the pump 104 to be dimensioned as accurately as possible to save space. Specifically, at reduced speeds, a smaller pump 104 can be used.

[0141] In a variation or in addition, the clutch 110 may be configured to move from the disengaged position to the engaged position when the oil pressure in the oil inlet line decreases and becomes less than a first threshold pressure, and / or to move from the engaged position to the disengaged position when the oil pressure in the oil inlet line increases and exceeds a second threshold pressure.

[0142] In some embodiments, the lubrication device 100 includes a second pump (not shown), which is different from the pump 104 including the pump rotor, and is configured to engage the drive shaft 11 when the rotational speed is greater than or equal to the threshold engagement speed N. D Oil is supplied to the speed reducer 19 at the same time.

[0143] For example, the pump 104 may form a so-called auxiliary pump operating in addition to or as a replacement for the second pump, which may form a so-called main pump also configured to lubricate the reducer 19 .

[0144] The main pump is configured to start when the speed of the drive shaft is greater than the threshold speed N A Lubricate the reducer 19 when necessary.

[0145] Threshold start speed N A Less than or equal to the threshold engagement speed N D .

[0146] When you select N A =N D When the main pump is used, the auxiliary pump 104 is disconnected via the clutch 110. Therefore, the auxiliary pump 104 and the main pump are used in different rotation speed ranges of the drive shaft.

[0147] When you select N A <N D When the main pump and the auxiliary pump 104 are in the speed range [N A N D ] simultaneously. For example, the auxiliary pump 104 can work during the startup phase of the main pump.

[0148] Threshold engagement speed N D It is possible to make a compromise between optimization of the space occupied by the main pump in the engine and the auxiliary pump in the retarder (the size of the pump is a function of its capacity) and lubrication (oil flow) over the entire speed range. For example, the threshold engagement speed N D The speed above which the main pump is activated and outputs at its nominal flow rate may be the speed above which the main pump is activated and outputs at its nominal flow rate. D The range can be a compromise between the size of the auxiliary pump and the capacity of the main pump.

[0149] When you select N A =0, the main pump is used at all speeds of the drive shaft.

[0150] The lubrication device 100 may include a check valve (not shown) to prevent oil from flowing back into the pump 104. When the pump 104 is an auxiliary pump 104, such a valve makes it possible to prevent the oil pumped by the main pump 104 from flowing back into the auxiliary pump 104.

[0151] Figure 7 A second embodiment of a lubrication device 100 is shown. This embodiment differs from the first embodiment in that the rotary element to which the pump rotor is rotationally coupled is one of the satellites 19c of the reducer 19, rather than the sun gear 19a. The satellite in question is thus connected to the pump rotor via a mechanical coupling adapted to rotate the satellite to drive the rotation of the pump rotor. This arrangement is not very space-consuming and, in particular, enables the utilization of space not previously occupied in the prior art.

[0152] Furthermore, in this second embodiment, the reducer 19 is located axially between the pump 104 and the drive shaft (this configuration is also seen in Figure 6 in the first embodiment).

[0153] If in this second embodiment a speed equal to the threshold engagement speed N is selected D The clutch 110 is configured to:

[0154] If the rotational speed of the drive shaft 11 is greater than or equal to the threshold engagement speed N D , the satellite 19c connected to the clutch is rotationally separated, and

[0155] If the rotation speed of the drive shaft 11 is less than the threshold engagement speed N D , the pump rotor is rotationally coupled to the satellite 19c.

[0156] In this second embodiment, the lubrication device 100 may include multiple pumps 104, as described above, each coupled to a different satellite 19c of the reducer 19. Thus, the lubrication device 100 may have as many pumps 104 as there are satellites 19c. In other words, the lubrication device comprises multiple pumps, each including a pump rotor, the plurality of pumps comprising at least two pumps and up to as many pumps as there are satellites, each pump rotor rotationally coupled to a different satellite 19c. The lubrication device is configured to lubricate the reducer 19 with oil as the pump rotors rotate. This configuration allows for the use of compact pumps, thereby optimizing volume. The pump assembly can be sized to deliver oil across the entire speed range, eliminating the need for a main pump, which saves space within the engine. Furthermore, the multiple pumps provide a degree of redundancy, thereby increasing the reliability of the lubrication device.

[0157] exist Figure 8 In the third embodiment shown, the mechanical coupling connecting the rotating element of the reducer 19 (the sun gear 19a or the satellite 19c) to the pump rotor comprises an intermediate gear 111 that does not form part of the reducer 19. The rotating element of the reducer 19 meshes with this intermediate gear 111, which is arranged to rotationally drive the pump rotor, where appropriate, via a clutch 110. The use of such an intermediate gear 111 makes it possible to offset the pump 104 in order to optimize the position of the pump and the volume of the system.

[0158] Furthermore, in this third embodiment, the speed reducer 19 is located axially between the pump 104 and the fan shaft 20 .

[0159] In a fourth embodiment (not shown), the rotating element is the ring gear 19b of the speed reducer 19. Therefore, the ring gear 19b is connected to the pump rotor by a mechanical coupling adapted to rotate the ring gear 19b to rotationally drive the pump rotor, the mechanical coupling not involving the fan shaft 20.

[0160] In a fifth embodiment (not shown), the rotating element is a fan shaft 20 .

[0161] 2) Brake for locking / unlocking the fan rotor

[0162] refer to Figure 9 , the propulsion system 1 may include a brake 200 configured to brake the rotation of the fan rotor 9 or to lock such rotation.

[0163] In the present disclosure, "braking" or "braking" an element should be interpreted as applying a force opposing the rotational motion of the element, but not locking that rotational motion. Thus, "braking" has the effect of slowing down the rotational speed of the braked element. In contrast, "locking" or "locking" an element has the effect of reducing the rotational speed of the element to zero and thus preventing the element in question from rotating.

[0164] Generally, brake 200 is configured to interact with an element of propulsion system 1 whose rotation is dependent on fan rotor 9. Thus, the element interacting with brake 200 receives the force generated by brake 200, which is transmitted directly or indirectly via the element to fan rotor 9. In the remainder of this document, the element interacting with brake 200 is referred to as the "element to be braked," with the understanding that the element to be braked can also be locked by brake 200.

[0165] To generate the locking or braking force, brake 200 is supplied with energy from an energy source. The greater the energy brake 200 receives from the energy source, the greater the force it generates. Thus, the energy required to apply the force to lock the braked element (and therefore the fan rotor 9) is greater than the energy required to enable brake 200 to apply the brake without locking. The energy source used can be any type of energy source. For example, the energy source is a battery (in which case the energy received by the brake is electrical energy).

[0166] For example, the default position of the brake 200 is a position in which the brake provides a locking of the fan rotor 9. The term "default position" should be understood to mean the position that the brake 200 adopts when the brake 200 is not supplied with energy (in particular when the propulsion system 1 is turned off). This default position can be obtained by appropriate return means (for example a spring).

[0167] Furthermore, the brake 200 can be configured to allow rotational movement of the fan rotor 9 by manual control (ie a manual control to be manually released) when the propulsion system 1 is shut down (ie when the combustion chamber is extinguished). This simplifies maintenance of the system.

[0168] The brake 200 may be a brake of any type (disc, claw, etc.). Any type of actuation of the brake 200 may be envisaged (electrical, pneumatic, hydraulic).

[0169] The propulsion system 1 may include a clutch 210 .

[0170] Brake 200 is configured to disengage clutch 210 when the rotational speed of drive shaft 11 increases and exceeds a first threshold speed. This first threshold speed may also be referred to as a second threshold disengagement speed (to avoid confusion between the second threshold disengagement speed and the threshold disengagement speed used for clutch 110, which has already been described in Section 1). Due to this, the safety and reliability of propulsion system 1 are increased because this avoids situations where the brakes may be applied in flight.

[0171] For example, the first threshold speed (or the second threshold separation speed) is between 50 rpm and 800 rpm, such as between 50 rpm and 400 rpm, such as between 100 rpm and 300 rpm.

[0172] Furthermore, the brake 200 is configured to engage the clutch 210 when the rotational speed of the drive shaft 11 decreases and becomes less than a second threshold speed (or a second threshold engagement speed, not to be confused with the threshold engagement speed of the clutch 110 described in Section 1). Thus, the operating range is optimized and safety is increased: specifically, the brake is disengaged more quickly in the case of acceleration, but is applied more quickly in the case of deceleration.

[0173] The second threshold speed (or second threshold engagement speed) is, for example, between 50 rpm and 800 rpm, such as between 50 rpm and 400 rpm, such as between 100 rpm and 300 rpm.

[0174] The first and second threshold speeds used by clutch 210 may be equal (which enables system simplification) or different.

[0175] When the first and second threshold speeds used by clutch 210 are equal, clutch 210 may be configured to:

[0176] If the rotational speed of the drive shaft 11 is greater than or equal to a first threshold speed, rotationally decoupling the pump rotor from the sun gear 19a, satellite gears 19c, ring gear 19d, fan shaft 20, or drive shaft 11, and

[0177] If the rotational speed of the drive shaft 11 is less than a first threshold speed, the pump rotor is rotationally coupled with the sun gear 19 a , the satellite gears 19 c , the ring gear 19 d , the fan shaft 20 or the drive shaft 11 .

[0178] The first threshold speed for clutch 210 may be the same as or different from the threshold disengagement speed for clutch 110 defined in Section 1. The second threshold speed for clutch 210 may be the same as or different from the threshold engagement speed N for clutch 110 defined in Section 1. D Same or different.

[0179] Furthermore, brake 200 can include a fuse (or safety section) configured to mechanically disconnect brake 200 from the rest of propulsion system 1. For example, the fuse can include a mechanical portion configured to disconnect once a threshold force is reached within the mechanism. This provides increased safety in the event of untimely and accidental brake 200 activation during flight. Specifically, in such a scenario, the fuse section can disconnect, and fan rotor 9 can then continue to rotate.

[0180] Figure 9 A first embodiment of a brake 200 is shown, wherein the clutch 210 is different from the clutch 110. In this first embodiment, the clutch 210 is arranged to couple or decouple the sun gear 19a and the brake 200.

[0181] Figure 10 A second embodiment of a brake 200 is shown, wherein the clutch 210 is different from the clutch 110. In this embodiment, the clutch 210 is arranged to couple or decouple the brake 200 and one of the satellites 19c.

[0182] Figure 11 A third embodiment of a brake 200 is shown, wherein clutch 210 and clutch 110 are actually the same clutch.

[0183] In this third embodiment, the second threshold engagement speed is the threshold engagement speed N defined in Section 1. D , the second threshold separation speed is the threshold separation speed defined in Part 1 (which may be equal to N D ). In this embodiment, the element to be braked is the rotor of the pump 104. Therefore, the same clutch 110 is used to control the activation of the pump 104 and therefore the lubrication of the retarder 19, and also to ensure that the brake 200 is properly decoupled from the retarder 19, so as to ensure that any involuntary actuation of the brake 200 has no effect on the retarder 19, in particular mid-flight.

[0184] The brake 200 is configured to brake when the rotation speed of the drive shaft 11 is less than the threshold braking speed N RThe rotation of the pump rotor is braked at the same time. This makes it possible to limit the movement of the fan rotor and reduce the oil required to lubricate the reducer 19. Specifically, due to the reduced speed, a smaller oil reservoir, a smaller pump, etc. can be used. In addition, by selecting the rotor of the pump 104 as the element to be braked, a fully integrated lubrication and braking system with reduced volume and mass is obtained (at least at low speeds). In addition, the braking phase makes it possible to gradually lock the propulsion system 1 (where appropriate) and avoid damage to the propulsion system 1.

[0185] For example, the threshold braking speed N R Between 30 rpm and 500 rpm, for example between 50 rpm and 300 rpm, for example between 80 rpm and 180 rpm. Braking above this speed allows the pump to be sized with a satisfactory compromise between volume, capacity / flow and braking capability (a small flow allows the use of a small pump).

[0186] Furthermore, the brake 200 is configured to engage when the rotation speed of the drive shaft 11 is less than the threshold locking speed N F The rotation of the braked element is locked at the time of the threshold locking speed N F Less than the threshold braking speed N R By means of this locking, lubrication of the reducer in the braking range is not required, the size of the pump 104 can be optimized and the integration of the system is improved, as is ground safety (the fact that the fan rotor is locked avoids accidents).

[0187] For example, the threshold locking speed N F Between 0 rpm and 200 rpm, such as between 0 rpm and 50 rpm, such as between 0 rpm and 20 rpm. Locking above this speed allows the pump 104 to be sized with a satisfactory compromise between volume, capacity / flow and braking capacity.

[0188] exist Figure 11 In the illustrated embodiment of the brake, the brake 200 includes a mechanical brake 202 and a valve system 204 .

[0189] The mechanical brake 202 is, for example, a friction brake, such as a disc brake, adapted to exert friction on the pump rotor. Such a brake is relatively compact.

[0190] Furthermore, the valve system 204 includes a first control valve 206 located downstream of the pump 104 and a second control valve 208 located upstream of the pump 104 .

[0191] A first valve 206 is disposed in the oil supply conduit 106. A second valve 208 is disposed in the oil inlet conduit 102. Each of the two valves 206 and 208 can be opened to allow oil to pass through, and can be closed to prevent oil from passing through. When the first valve 206 is closed, the first valve 206 prevents oil from the pump 104 from being delivered to the fluid distributor 110. When the second valve 208 is closed, the second valve 208 prevents oil from the oil source from being delivered to the pump 104 through the oil inlet conduit 102.

[0192] To lock, the valve system 204 can be actuated as follows. The first downstream valve 206 is closed, followed by the second upstream valve 208. This has the effect of placing the pump 104 under overpressure and blocking any oil flow at the inlet / outlet of the pump 104, which has the effect of rotationally locking the pump rotor. To release the hydraulic brake 204, it is sufficient to first open the downstream valve and then the upstream valve. After the brake is released, the pump rotor is allowed to rotate again.

[0193] The valve system 204 may also include a check valve 208 adapted to gradually increase the pressure within the pump 104 and thus perform braking without locking.

[0194] The valve system 204 described above is particularly compact and lightweight (especially compared to mechanical locking / unlocking systems).

[0195] For example, the valve system 204 can be dedicated to locking of the pump rotor, while the mechanical brake 202 can be dedicated to braking (decelerating without locking). In a variant, the mechanical brake can be used to participate in braking and in locking.

[0196] Combining valve system 204 and mechanical brake 202 within brake 200 allows for optimization of both lubrication performance and braking performance. However, brake 200 may comprise only the valve system 204 discussed above (then brake 200 does not include any mechanical brake). Thus, brake 200 is even more compact and lighter. Alternatively, brake 200 may consist of the mechanical brake 202 discussed above (then brake 200 does not include any valve system).

[0197] Control of the brake 200 may depend on at least one operating state of the lubrication device 100 .

[0198] The brake 200 may be hydraulically controlled, with the hydraulic control being fluidly connected to the lubrication device 100. This allows the brake to be more compact and provides the opportunity to use a nearby energy source.

[0199] To achieve this hydraulic control, the brake 200 may include a switch for enabling and disabling the brake. When the brake is disabled, even if a certain amount of energy reaches the brake via the energy source discussed above, the brake cannot generate any braking force. Only when the brake is enabled can this energy be converted into braking / locking force by the brake. The activation of the brake 200 may be conditional on the operation of the pump 104. For example, the switch may be operated to a position that enables the brake 200 by circulating oil through the lubricating device 100. If there is no such fluid circulation, a reset device (e.g., a spring) may be used, for example, to switch the switch to another position that disables the brake.

[0200] Of course, the brake 200 is compatible with all embodiments of the lubricating device 100 described in part 1). In particular, the brake 200 can be combined with an embodiment of the lubricating device 100 in which the pump rotor is connected to the sun gear 19a ( Figure 6 ) or satellite unit 19c( Figure 7 and Figure 8 ) are rotationally coupled. A synergistic effect is thus achieved because braking is performed on the "faster" rotating gear and transmits less torque. At this time, the torque to be applied is reduced due to the reduction ratio of the reducer 19, thereby reducing the braking force and, consequently, the size of the brake 200.

[0201] 3) Lubrication device and brake operating area

[0202] In the aforementioned sections 1 and 2, the following threshold speeds were defined:

[0203] ·N D : threshold engagement speed for use of the clutch 110 associated with the pump 104 (auxiliary pump) of the lubrication device 100 ;

[0204] ·N A : threshold starting speed of the second pump (main pump) of the lubricating device 100;

[0205] ·N R : threshold braking speed used by the brake 200;

[0206] ·N F : threshold locking speed for brake 200 use;

[0207] For example, the threshold speeds defined in the preceding sections follow the following relationship:

[0208] 0 <N F <N R <N A ≤N D

[0209] Figure 131 shows the operating region of the pump 104 when the pump 104 is an auxiliary pump 104 combined with a main pump. In this embodiment, N A <N D .

[0210] Auxiliary lubrication (ie, provided by the auxiliary pump 104) is provided in the speed range [0, N D ] within the range. The auxiliary pump 104 can be started, for example, above 2tr / min. The main lubrication involves the speed range [N A , N MAX ] within. MAX is the maximum speed of the drive shaft (not shown). For example, N MAX Equal to 12.000tr / min.

[0211] The locking performed by the brake 200 is in the range [0, N F ] within.

[0212] Braking (resulting in deceleration without locking) in the range [N F , N R ] (or where appropriate, if locking is not required, in the range [0, N R ]).

[0213] Alternatively, the lubrication provided by the pump 104 is maintained over the entire possible speed range of the drive shaft (i.e., from 0 to N MAX Provide lubrication within the range).

[0214] 4) Shared devices for controlling the pitch of the blades and controlling the brakes

[0215] refer to Figure 13 The propulsion system includes a control system 300 , which is used to control the pitch of the blades 19 of the fan rotor, in particular to control the feathering of the blades 19 .

[0216] The control system 300 includes the pitch changing mechanism 15 described above, a hydraulic control circuit 302 and a hydraulic fluid source 304 .

[0217] Hydraulic circuit 302 fluidly connects source 304 to pitch change mechanism 15. Hydraulic circuit 302 is configured to deliver fluid from source 302 to mechanism 15 to actuate the mechanism 15. Thus, the fluid delivered by the hydraulic circuit delivers hydraulic energy that forces pitch change mechanism 15 to shift, thereby changing the orientation of blades 19 relative to the hub and, therefore, changing the pitch of the blades. In other words, pitch change mechanism 15 is hydraulically actuated.

[0218] Furthermore, brake 200 can be configured to lock the rotation of the fan rotor upon command to feather the blades. In other words, any feathering of blades 19 is accompanied by a locking of fan rotor 9 by brake 200. Thus, control system 300 becomes universal, eliminating the need for a dedicated control system for brake 200, which saves space and mass. The control system is simpler than prior art systems, and lubrication at low speeds (e.g., via an auxiliary pump) is no longer required because the engine is no longer running.

[0219] Furthermore, the brake 200 can be configured to unlock the rotation of the fan rotor 9 upon a command issued by the control system 300 to unfeather the blades 19. This command is simple and effective.

[0220] Brake 200 can be configured to be actuated by energy that also enables a change in the pitch of the blades to be actuated. This can make system 1 more compact, since brake 200 benefits from a nearby energy source already available to generate the braking / locking force, and makes control easier to synchronize. In other words, brake 200 uses a portion of the energy dedicated to changing the pitch of the blades of fan rotor 9 to perform the brake's braking / locking function.

[0221] For example, the energy used by the brake is hydraulic energy transmitted by a hydraulic circuit. In this embodiment, the brake 200 is hydraulically actuated, just like the pitch change mechanism 15. This is easier to implement than systems involving electrical or mechanical energy, and the system is more compact and has a lower mass.

[0222] When the brake 200 is hydraulically actuated, the hydraulic actuation device can be connected to the control system 300. More specifically, the brake 200 is fluidically connected to the hydraulic control circuit 302. The hydraulic actuation of the brake 200 can be direct or indirect. For example, even if the control system 300 is in a passive standby state (i.e., in the feathering position or with the brake locked), hydraulic actuation can still be performed, for example, by means of a counterweight, the control system maintaining hydraulic pressure to counteract the effect of the counterweight at a given time.

[0223] The control system 300 may further include a first delay timer configured to delay the rotational locking relative to the feathering of the blades. Thus, it is possible to wait for the feathering operation to take effect before locking.

[0224] For example, the control system 300 may further include a second delay timer configured to delay the unfeathering of the blades relative to the unlocking of the rotation of the fan rotor.

[0225] The use of the first delay timer and / or the second delay timer makes it possible to reduce restrictions and more accurately determine the dimensions of certain components, thereby saving space and reducing mass.

[0226] For example, the first delay timer or the second delay timer includes a time counter, and locking can be triggered when the time counter reaches a predetermined time.The first delay timer and the second delay timer can be the same delay timer, or can be different delay timers.

[0227] exist Figure 13 , a first delay timer is represented by block 308 at the hydraulic circuit 302 , it being understood that these delay timers may be incorporated into the brake 200 .

[0228] Figure 13 Shown and according to Figure 10 The control system 300 is a combination of the brake 200 of the embodiment of the present invention, wherein the element braked by the brake is the satellite 19c of the retarder 19. Of course, the control system 300 described above can be combined with other embodiments of the brake 200 shown in part 2 above (especially Figure 9 An embodiment of the brake 200 and Figure 11 ) combination of the brake 200, in Figure 9 In the embodiment of the brake 200, the brake element is the sun gear 19a. Figure 11 In the embodiment of the brake 200 , the brake element is the rotor of the pump 104 .

[0229] refer to Figure 14 The braking method implemented using the control system 300 includes the following steps.

[0230] The control system 300 detects that feathering of the fan blades must be triggered.

[0231] In response to this detection, control system 300 issues a command to feather the fan blades (step S1). To this end, hydraulic circuit 302 delivers fluid from source 304 to pitch change mechanism 19. The fluid delivers hydraulic energy, which forces pitch change mechanism 15, causing it to shift fan blades 19 to their feathered position.

[0232] Furthermore, since hydraulic circuit 302 is hydraulically connected to brake 200, a portion of the hydraulic energy actuates brake 200, causing brake 200 to lock the fan rotor. When the first delay timer is used, this locking occurs after feathering of the fan blades.

[0233] As previously mentioned, in some embodiments, the rotor of the pump 104 can participate in transmitting the locking force generated by the brake 200 to the reducer 19, and then transmit the locking force to the fan rotor 9. In embodiments where the brake 200 includes valves 206 and 208, the locking step S2 includes Figure 15The following steps are shown in FIG: the control system 300 controls the downstream valve 206 to close (step S20) via the fluid traveling through the hydraulic circuit 302, and then controls the upstream valve 208 to close (step S21). This causes an overpressure of the oil in the pump 104, which causes the pump rotor to lock.

[0234] Subsequently, the control system 300 detects that de-feathering of the fan blades must be triggered.

[0235] In response to this detection, the control system 300 issues a command to de-feather the fan blades (step S3). To this end, the device 304 causes fluid to be delivered through the hydraulic circuit 302. The fluid delivers hydraulic energy, which forces the pitch change mechanism 15 to move the fan blades 19 out of the feathered position of the fan blades.

[0236] Furthermore, since hydraulic circuit 302 is connected to brake 200, a portion of the hydraulic energy releases brake 200, causing brake 200 to stop locking the fan rotor (step S4). When the second delay timer is used, this release occurs before the fan blades are released from feathering. In embodiments where brake 200 includes valves 206 and 208, unlocking step S3 includes Figure 16 : The control system 300 controls the first downstream valve 206 to open (step S30) via the fluid flowing through the hydraulic circuit 302, and then controls the upstream valve 208 to open (step S31). At this time, the pump rotor is unlocked, allowing the rotating elements of the speed reducer 19 and the fan rotor 19 to rotate. At the same time, the rotor 104 begins to supply oil to the speed reducer 19 again, thereby lubricating the speed reducer 19.

[0237] Thus far, an embodiment has been described in which brake 200 uses control system 30 as an energy source for varying the pitch of fan blades 19. In other embodiments, complementary or alternative energy sources (particularly: air starters, batteries, etc.) may be used for brake 200.

[0238] 5) Other embodiments

[0239] For the propulsion system 1 , other embodiments of the lubrication device 100 , the brake 200 and / or the control system 300 are conceivable.

[0240] in particular:

[0241] ·although Figure 11Only a single brake 200 coupled to the satellite 19 c is shown, but the propulsion system 1 may include a plurality of brakes 200, each coupled to a different satellite 19 c of the reducer 19. The use of a plurality of brakes makes it possible to improve efficiency and compactness: in particular, a plurality of small brakes used together can provide braking similar to that of a large brake, but with an optimized volume; in addition, the redundancy of the plurality of small brakes used together increases the safety of the system.

[0242] As mentioned above, the brake 200 can be independent of the pump 104 and, more generally, of the lubrication device 100. The element braked by the brake 200 does not necessarily have to be part of the retarder 19: it can specifically be the fan shaft 20 or the drive shaft 11. All these alternatives make it possible to save space in the engine.

[0243] • The brake 200 is not necessarily hydraulically actuated. In a variant, the brake 200 can be actuated using a worm screw (eg a ball screw or the like).

[0244] • The actuator 200 may change the pitch of the blades 19 using one or more energy sources independent of the control system 300 (including: air actuators, batteries, etc.).

[0245] Advantageously, the lubricating device 100 and / or the brake 200 are combined with the planetary reducer 19, since this combination leads to a simplification of the structure and thus to a volume saving associated with easier integration. Nevertheless, it is still possible to combine the lubricating device 100 and / or the brake 200 with a planetary reducer.

[0246] Different strategies can be envisaged: the brake 200 can be engaged by default with the clutch 210 and, where appropriate, can be used in conjunction with another brake (eg an electromagnetic brake for energy recovery).

Claims

1. An aviation propulsion system (1), comprising: A fan rotor (9) comprising variable pitch blades (19); a control system (300) configured to control the pitch of the blades, in particular to feather the blades (19); A brake (200) configured to lock the rotation of the fan rotor (9) in response to a command from the control system to feather the blades (19).

2. The aircraft propulsion system (1) according to claim 1, comprising a delay timer configured to delay the locking of the brake (200) relative to the feathering of the blade (19) by the control system (300).

3. The aviation propulsion system (1) according to claim 1 or 2, wherein: The brake (200) is configured to unlock the rotation of the fan rotor (9) in response to a command from the control system (300) to unfeather the blades (19).

4. The aviation propulsion system (1) according to claim 3, comprising a delay timer configured to delay the unfeathering of the blades (19) by the control system (300) relative to the unlocking of the rotation of the fan rotor (9) by the brake (200).

5. The aviation propulsion system (1) according to any one of claims 1 to 4, comprising a drive shaft (11), wherein: The brake (200) is configured to disengage when the rotational speed of the drive shaft (11) increases and exceeds a threshold disengagement speed, the threshold disengagement speed being, for example, between 50 rpm and 800 rpm, for example, between 50 rpm and 400 rpm, for example, between 100 rpm and 300 rpm.

6. The aviation propulsion system (1) according to any one of claims 1 to 5, comprising a drive shaft (11), wherein: The brake (200) is configured to engage when the rotation speed of the drive shaft (11) decreases and becomes less than a threshold engagement speed (N D ) is engaged, the threshold engagement speed (N D ) for example between 50 rpm and 800 rpm, for example between 50 rpm and 400 rpm, for example between 100 rpm and 300 rpm.

7. The aircraft propulsion system (1) according to any one of claims 1 to 6, comprising a fuse for mechanically isolating the brake (200) from the rest of the system.

8. The aviation propulsion system (1) according to any one of claims 1 to 7, wherein: The brake (200) is configured to be actuated by energy that also causes a change in the pitch of the blades (19).

9. The aviation propulsion system (1) according to claim 8, wherein: The control system (300) includes a hydraulic circuit (302) connected to the brake (200), and the energy is hydraulic energy delivered by the hydraulic circuit.

10. The aviation propulsion system (1) according to any one of claims 1 to 9, comprising: Drive shaft (11); A fan shaft (20) for rotationally driving the fan rotor (9); a speed reducer (19) that rotationally couples the drive shaft (11) and the fan shaft (20) and is configured to drive the fan shaft (20) at a rotation speed lower than that of the drive shaft (11), the speed reducer (19) comprising: a sun gear (19a) having a diameter and being rotationally coupled to the drive shaft (11); a satellite portion (19c) meshing with the sun gear (19a); a ring gear (19d) having a diameter and meshing with the satellite (19c), the ring gear (19b) having a diameter greater than the diameter of the sun gear (19a); · wherein the brake (200) is configured to lock the rotation of the sun gear (19a), the satellite (19c), the ring gear (19d), the drive shaft (11) or the fan shaft (20).

11. The aviation propulsion system (1) according to claim 10, wherein: The brake (200) is configured to lock the rotation of the sun gear (19a) or the satellite (19c).

12. The aviation propulsion system (1) according to claim 10 or 11, wherein: The aircraft propulsion system comprises a lubrication device (100), the lubrication device comprising a pump (104), the pump (104) comprising a pump rotor and being configured to supply oil to the speed reducer (19) when the pump rotor rotates, wherein the brake (200) is configured to interact with the pump rotor.

13. The aviation propulsion system (1) according to claim 12, wherein: The control of the brake (200) depends on at least one operating state of the lubrication device (100).

14. The aviation propulsion system (1) according to claim 12 or 13, wherein: The brake (200) is hydraulically controlled, and a hydraulic control device is fluidly connected to the lubrication device.

15. Aviation propulsion system (1) according to any one of claims 12 to 14 in combination with claims 5 and 6, wherein: The threshold disengagement speed is equal to the threshold engagement speed (N D ), the system comprising a clutch (110), the clutch being configured to: When the rotation speed of the drive shaft (11) is greater than or equal to the threshold engagement speed (N D ), the pump rotor is rotationally separated from the sun gear (19a), the satellite portion (19c), the ring gear (19d), the fan shaft (20) or the drive shaft (11), and When the rotation speed of the drive shaft (11) is less than the threshold engagement speed (N D ), the pump rotor is rotationally coupled to the sun gear (19a), the satellite gear (19c), the ring gear (19d), the fan shaft (20) or the drive shaft (11).

16. The aviation propulsion system (1) according to claim 15, wherein: The lubrication device (100) includes a second pump, which is different from the pump including the pump rotor, and the second pump is configured to engage the drive shaft (11) when the rotational speed is greater than or equal to the threshold engagement speed (N D ) when supplying oil to the reducer (19).

17. The aviation propulsion system (1) according to any one of claims 12 to 16, wherein: The brake (200) comprises only a valve system including a first control valve located downstream of the pump and a second control valve located upstream of the pump.

18. The aviation propulsion system (1) according to any one of claims 12 to 16, wherein: The brake (200) comprises a mechanical brake.

19. The aviation propulsion system (1) according to claim 18, wherein: The brake (200) includes a valve system comprising a first control valve located downstream of the pump and a second control valve located upstream of the pump.

20. The aviation propulsion system (1) according to any one of claims 10 to 19, wherein: The speed reducer (19) comprises a planet carrier (19d) on which the satellite part (19c) is rotatably mounted, and the planet carrier (19d) is fixed relative to the stator of the propulsion system.

21. The aeronautical propulsion system (1) according to claim 20, extending along an axial direction (X), wherein: Considering the axial direction, the speed reducer (19) is located between the pump (104) and the drive shaft (11).

22. The aviation propulsion system (1) according to claim 20 or 21, extending along an axial direction (X) and further comprising a supply duct (102) for supplying oil to the pump (104), wherein The supply pipe (102) axially crosses the reducer (19).

23. The aviation propulsion system (1) according to claim 20 or 21, wherein: The speed reducer (19) includes a plurality of satellite parts (19c), The lubrication device comprises a plurality of pumps, each pump comprising a pump rotor, the plurality of pumps comprising at least two pumps and at most as many pumps as there are satellites, each pump rotor being rotationally coupled to a different satellite (19c), the lubrication device being configured to lubricate the reducer (19) with oil when the pump rotor rotates.

24. A method for braking a fan rotor (9) of a propulsion system, the method comprising: The rotation of a fan rotor (20) including variable pitch blades (19) is locked according to the feathering of the blades (19).

25. The braking method according to claim 24, wherein: Locking the rotation is performed after feathering the blades (19).

26. The braking method according to claim 24 or 25, wherein: The method includes unfeathering the blades (19) after unlocking the fan rotor.

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