Geared motor unit for an aircraft

Abstract

A geared motor unit (10) for an aircraft, this geared motor unit (10) comprising an electric motor (12) and a mechanical reduction gear (14), the reduction gear (14) comprising a sun gear (26) rotationally movable about an axis (A), a ring gear (28), and planet gears (30) which are interposed between the sun gear (26) and the ring gear (28) and mesh with the sun gear (26) and the ring gear (28), the planet gears (30) being carried by a planet carrier (32), the geared motor unit further comprising a lubrication circuit (60) for lubricating the meshings of the reduction gear (14), characterized in that the lubrication circuit (60) is separate and is installed inside the geared motor unit (10).

Description

[0001] DESCRIPTION

[0002] TITLE: GEARED MOTOR FOR AN AIRCRAFT

[0003] Technical field of the invention

[0004] The present invention relates in particular to a geared motor for an aircraft, as well as to an aircraft comprising such a geared motor.

[0005] Technical approval plan

[0006] The state of the art includes in particular documents FR-A1 -2 987 416, FRAI -2 853 382, ​​FR-A1 -3 041 054, FR-A1 -3 073 915, FR-A1-3 084 428, US-B1 -11 787 551, US-B2-11 794 913 and W0-A1 -2022 / 123229.

[0007] The combination of an electric motor and a mechanical reducer forms a geared motor.

[0008] The role of a mechanical reducer is to modify the speed ratio and torque between the input shaft and the output shaft of a mechanism.

[0009] New generations of dual-flow turbomachines, particularly those with a high bypass ratio, include a mechanical reducer to drive the shaft of a fan. Typically, the reducer is used to transform the so-called fast rotation speed of the shaft of a power turbine into a slower rotation speed for the shaft driving the fan.

[0010] Such a reducer comprises a central pinion, called a sun gear, a crown gear and pinions called planet gears, which are meshed between the sun gear and the crown gear. The planet gears are held by a frame called a planet carrier. The sun gear, the crown gear and the planet carrier are planet gears because their axes of revolution coincide with the longitudinal axis of the turbomachine. The planet gears each have a different axis of revolution equally distributed over the same operating diameter around the axis of the planet gears. These axes are parallel to the longitudinal axis of the turbomachine. There are several reducer architectures. In the state of the art of double-flow turbomachines, the reducers are of the planetary or epicyclic type. In other similar applications, there are architectures called differential or "compound".

[0011] - on a planetary reducer, the planet carrier is fixed and the crown constitutes the output shaft of the device which rotates in the opposite direction to the solar.

[0012] - on an epicyclic reducer, the crown is fixed and the planet carrier constitutes the output shaft of the device which rotates in the same direction as the solar.

[0013] - on a differential reducer, no element is fixed in rotation. The crown rotates in the opposite direction to the sun and the planet carrier.

[0014] Gearboxes can be composed of one or more meshing stages. This meshing is ensured in different ways such as by contact, friction or even by magnetic field. There are several types of contact meshing such as with straight or herringbone teeth.

[0015] A gearbox requires lubrication to function properly. It is difficult to provide a lubrication unit outside the gearbox because the electric motor is not designed for this purpose. One solution to this problem could be to splash the rotating parts of the gearbox in oil. However, the resulting "splashing" would not be effective enough to ensure proper lubrication of the gears.

[0016] The present invention provides a solution to this problem, which is simple, effective and economical.

[0017] Summary of the invention

[0018] The invention relates to a geared motor for an aircraft, this geared motor comprising an electric motor and a mechanical reducer, the reducer comprising a mobile sun gear rotating about an axis, a crown, and satellites interposed between the sun gear and the crown gear and meshed with the sun gear and the crown gear, the satellites being carried by a planet carrier, the geared motor further comprising a circuit for lubricating the gear meshes, characterized in that the lubrication circuit is autonomous and installed inside the geared motor, the lubrication circuit comprising a lubricating oil reservoir, at least one pump located in the reservoir and capable of being immersed in the lubricating oil contained in the reservoir, and nozzles connected to the pump, the pump comprising a rotor which is rotated by the sun gear for drawing oil from the reservoir and supplying oil to said nozzles.

[0019] The particularity of the invention is linked to the fact that the lubrication of the reducer and in particular of its gears is carried out autonomously by a circuit which is integrated into the reducer. The circuit comprises a reservoir, at least one pump and nozzles. The entire circuit is located inside the reducer. The reducer is therefore designed to contain its own lubrication reservoir. The pump is immersed in the oil in the reservoir and supplies the nozzles. As soon as the reducer is operating, the solar turns and the pump is actuated to supply oil to the nozzles.

[0020] In this application, an "autonomous" circuit is understood to mean a circuit that operates without external assistance or energy input. The operation of the geared motor is therefore sufficient to operate the lubrication circuit. In particular, the rotation of the solar panel drives the pump rotor and the supply of oil to the nozzles. The pump is intended to be in contact with the oil and therefore to be immersed in the oil for the purpose of withdrawing it and supplying oil to the circuit.

[0021] The present invention is compatible:

[0022] - a single-stage or multi-stage reducer;

[0023] - straight, helical or herringbone teeth;

[0024] - any type of single-piece or cage and cage-holder type planet carrier;

[0025] - any type of satellite guide bearings, such as rolling element or hydrodynamic bearings. The geared motor according to the invention may comprise one or more of the following characteristics, taken in isolation from one another, or in combination with one another; these characteristics having in particular the advantages of making the geared motor more compact:

[0026] - the reservoir is delimited or located in the solar, and preferably is formed by the solar, in particular when the geared motor is in a default operating position;

[0027] -- in the default position, the main axis of the geared motor is oriented vertically;

[0028] -- in another position, in which the main axis of the geared motor is oriented horizontally, the oil contained in the geared motor can be stored inside the planet carrier and / or the casing;

[0029] - the solar has a general L or C shape in axial section and comprises an internal cylindrical wall which comprises or carries external teeth, a radial annular wall which extends from the internal cylindrical wall towards the outside, and an external cylindrical wall which extends around the internal cylindrical wall and which is connected to the external periphery of the radial wall, at least some of these walls of the solar defining between them said reservoir;

[0030] - the solar further comprises an internal cylindrical rib which is located between the internal and external cylindrical walls, and at a distance from the latter, and which is connected to the radial wall, this rib defining the tank with the radial wall and the internal cylindrical wall;

[0031] - the pump is connected to the nozzles by an annular oil distributor which extends around the axis;

[0032] - the pump and the nozzles are carried by the oil distributor which includes fixing lugs to the planet carrier;

[0033] - the nozzles extend inside the crown, parallel to the axis, and are interposed circumferentially between the satellites; - the number of nozzles is equal to the number of satellites, each of the satellites being associated with a nozzle which is located between this satellite and a circumferentially adjacent satellite;

[0034] - the number of nozzles is equal to twice the number of satellites, each of the satellites being associated with two nozzles which are located circumferentially on either side of the satellite;

[0035] - the geared motor further comprises a system for controlling the oil in the geared motor;

[0036] - the control system includes a sensor or window through which an operator can view the presence of oil, or even the oil pressure, in the gear motor;

[0037] - the window or sensor is located on a gear motor housing and is aligned with the projection axis of an oil projection nozzle;

[0038] - the oil spray nozzle is carried by the planet carrier and fluidically connected to the oil distributor, preferably by an oil pipe formed in the planet carrier;

[0039] - the pump is of the gerotor or vane or gear type;

[0040] - the planet carrier is fixed and the crown is mobile in rotation around the axis.

[0041] - the pump rotor and the satellites are driven by the same toothing of the solar;

[0042] -- the distributor also supplies plain bearings for guiding the satellites;

[0043] - the reducer is coupled to the geared motor.

[0044] The invention further relates to an aircraft comprising a geared motor as described above, in particular for driving a propulsion propeller.

[0045] Brief description of the figures Other characteristics and advantages will emerge from the following description of a non-limiting embodiment of the invention with reference to the appended drawings in which:

[0046] [Fig.1] Figure 1 is a schematic exploded perspective view of a geared motor according to the invention;

[0047] [Fig.2] Figure 2 is a schematic axial sectional view of the geared motor of Figure 1;

[0048] [Fig.3] Figure 3 is a schematic axial sectional view of the geared motor of Figure 1, in a first position and illustrates the storage of the oil in the reservoir in this first position;

[0049] [Fig.4] Figure 4 is a schematic axial sectional view of the geared motor of Figure 1, in a second position and illustrates the storage of the oil in the reservoir in this second position;

[0050] [Fig.5] Figure 5 is a schematic cross-sectional view of the geared motor of Figure 1, and shows a lubrication circuit of this geared motor; and

[0051] [Fig.6] Figure 6 is a partial schematic axial sectional view of the geared motor of Figure 1, and shows a control window of the geared motor.

[0052] Detailed description of the invention

[0053] Figures 1 to 6 illustrate an embodiment of a geared motor 10 according to the invention, this geared motor being particularly suitable for use in an aircraft.

[0054] The aircraft is for example of the VTOL type, i.e. vertical takeoff and landing. The geared motor 10 can for example be used to drive the propulsion propeller or one of the propulsion propellers of the aircraft.

[0055] Advantageously, the geared motor 10 is designed to drive the propeller around a vertical axis. However, it is understood from the following description that the axis of rotation of the propeller can have any orientation. The geared motor 10 comprises an electric motor 12 and a mechanical reducer 14.

[0056] The electric motor 12 has an annular shape and is aligned on an axis A, which is a common axis with the reducer 14.

[0057] As mentioned above, this axis A can be oriented vertically, in particular during takeoff or landing of the aircraft. The electric motor 12 comprises a rotor 16 and a stator 18. In the example shown, the rotor 16 is located inside the stator 18.

[0058] In the example shown, the rotor 16 comprises an annular row of permanent magnets 20. These magnets 20 may be separated from each other by spacers. The number of magnets 20 may be greater than 20 or 30 for example.

[0059] The stator 18 may comprise an annular row of windings (not shown) which are formed by winding around cores 24. The number of cores 24 is for example equal to the number of permanent magnets 20.

[0060] The reducer 14 may be of the planetary type, that is to say that it comprises a movable crown and a fixed planet carrier.

[0061] The reducer 14 thus comprises a sun gear 26 movable in rotation around the axis A, a crown 28 movable in rotation around this axis A, and satellites 30 interposed between the sun gear 26 and the crown 28 and meshed with the sun gear 26 and the crown 28.

[0062] The satellites 30 are carried by a planet carrier 32 which is fixed. Conventionally, each of the satellites 32 is mounted on an axis which forms a smooth bearing or around which a rolling bearing is mounted.

[0063] In the example shown, the solar 26 has a general L or C shape in axial section and comprises:

[0064] - an internal cylindrical wall 26a which comprises or carries an external toothing 33,

[0065] - a radial annular wall 26b which extends from the internal cylindrical wall 26a towards the outside, - and possibly an external cylindrical wall 26c which extends around the internal cylindrical wall 26a and which is connected to the external periphery of the radial wall 26b.

[0066] In the example shown, the rotor 16 is directly fixed to the outer periphery of the radial wall 26b or to the outer cylindrical wall 26c, or the stator 18 is directly carried by the outer periphery of the radial wall 26b or by the outer cylindrical wall 26c.

[0067] Advantageously, the geared motor 10 comprises a first bearing 34 for guiding the sun gear 26, which is mounted between the sun gear 26 and the planet carrier 32, and a second bearing 36 for guiding the sun gear 26, which is mounted between the sun gear 26 and the ring gear 28.

[0068] The first bearing 34 preferably has a diameter greater than that D2 of the teeth 33 of the sun 26

[0069] The second bearing 36 preferably has a diameter smaller than that of the teeth 33 of the sun 26.

[0070] In the example shown, the first bearing 34 is carried by the radial wall 26b, and the second bearing 36 is located inside the internal cylindrical wall 26c.

[0071] In the example also shown, the crown 28 has a general L or C shape in axial section and comprises:

[0072] - an external cylindrical wall 28a which comprises or carries an internal toothing 38,

[0073] - a radial annular wall 28b which extends from the external cylindrical wall 28a inwards,

[0074] - and possibly an internal cylindrical wall 28c which extends inside the external cylindrical wall 28a and which is connected to the internal periphery of the radial wall 28b.

[0075] The rotor 16 may extend at least partly around the internal toothing 38 of the crown 28. The geared motor 10 further comprises an output shaft 50 in the example shown, which is coupled by splines 40 to the internal periphery of the radial wall 28b or to the internal cylindrical wall 28c.

[0076] As in the example shown, the planet carrier 32 is fixed to a casing 42 of the geared motor 10.

[0077] The stator 18 of the motor 12 may be attached directly to the housing 42 or carried directly by the housing 42.

[0078] The casing 42 may have a general L or C shape in axial section and comprise:

[0079] - an external cylindrical wall 42a,

[0080] - a radial annular wall 42b which extends from the external cylindrical wall inwards,

[0081] - and possibly an internal cylindrical wall 42c which extends inside the external cylindrical wall 42a and which is connected to the internal periphery of the radial wall 42b.

[0082] The geared motor 10 may comprise a bearing 44 for guiding the output shaft 50, this bearing 44 being mounted between the output shaft 50 and the internal periphery of the radial wall 42b or the internal cylindrical wall 42c of the casing 42.

[0083] The planet carrier 32 can be fixed to the radial wall 42b of the casing 42, as in the example shown.

[0084] According to the invention, the geared motor 10 further comprises a lubrication circuit 60 for the gears of the reducer 14, i.e. the gears between the teeth of the sun gear 26 and the planet gears 30, and between the teeth of the planet gears 30 and the crown wheel 28.

[0085] The lubrication circuit 60 is autonomous and is installed inside the geared motor 10. This lubrication circuit 60 comprises a reservoir 62 of lubricating oil, at least one pump 64 located in the reservoir 62 and capable of being immersed in the lubricating oil 66 contained in the reservoir 62, and nozzles 68 connected to the pump 64. The pump 64 comprises a rotor 64a which is coupled to the solar 26 and which is capable of being driven in rotation by the solar 26 for drawing oil 66 from the reservoir 62 and supplying oil to the nozzles 68.

[0086] Advantageously, it is the same toothing 33 of the solar 26 which drives both the satellites 32 and the rotor 64a of the pump 64.

[0087] The pump 64 is for example of the gerotor or vane or gear type. Figure 3 shows the geared motor 10 in its default position in the aircraft. It is oriented so that its axis A is vertical so that the propeller which drives it rotates around the vertically oriented axis A. In this position, the reservoir 62 is located in the solar 26, and in particular is formed by the solar 26.

[0088] In the example shown, at least some of the walls 26a, 26b, 26c of the solar panel 26 define the reservoir 62 between them.

[0089] The solar 26 may comprise an internal cylindrical rib 26d which is located between the internal and external cylindrical walls 26a, 26c, and at a distance from the latter, and which is connected to the radial wall 26b.

[0090] The rib 26d may define the reservoir 62 with the radial wall 26b and the internal cylindrical wall 26a.

[0091] Figure 4 shows the geared motor 10 in another position in which it is oriented so that its axis A is horizontal. It may be the same geared motor 10 mounted in the same aircraft but which has adopted a different orientation in which its propeller rotates about the horizontally oriented axis A. In this position, the oil 66 has flowed into the geared motor 10 and adopts a new position. In the example shown, the oil is contained inside the planet carrier 32 and the casing 42. In this position, the pump 64 is temporarily no longer immersed in the oil.

[0092] The lubrication circuit 60 preferably comprises a distributor 70 which connects the pump 64 to the nozzles 68, and which is visible in Figures 1 and 5 in particular. The distributor 70 preferably has an annular shape to extend around the axis A.

[0093] The distributor 70 is fixed to the planet carrier 32 and for this purpose comprises fixing lugs 82 which are applied and fixed to the planet carrier 32, by means of screws 84 or bolts for example.

[0094] The distributor 70 is preferably formed in one piece with the legs 82 and at least a portion of the nozzles 68.

[0095] The nozzles 68 may extend inside the crown 28, parallel to the axis A, and be circumferentially interposed between the satellites 30.

[0096] In a first embodiment, the number of nozzles 68 is equal to the number of satellites 30, each of the satellites 30 being associated with a nozzle 68 which is located between this satellite and a circumferentially adjacent satellite. In an alternative embodiment, which is that illustrated in the drawings, the number of nozzles 68 is equal to twice the number of satellites 30, each of the satellites 30 being associated with two nozzles 68 which are located on either side of the satellite. This configuration is advantageous because the nozzles 68 are capable of lubricating the gears, upstream and downstream of the satellites 30, regardless of the direction of rotation of the solar 26.

[0097] Figure 6 shows a system 80 for controlling the oil in the geared motor 10, this control system 80 comprising a window 82 through which an operator or a sensor 83 can view the presence of oil, or even the oil pressure, in the geared motor 10. Alternatively, this window 82 could be replaced by a sensor.

[0098] In the example shown, the window 82 is formed in or carried by the casing 42 of the geared motor 10.

[0099] The window 82 is aligned with an oil pipe 84 formed in the planet carrier 30, this oil pipe 84 being connected to the distributor 70 and being supplied with oil by the latter. It is therefore understood that the distributor 70 supplies both the nozzles 68 and the pipe 84 formed in the planet carrier 30. The pipe 84 may have an elongated shape along an axis B parallel to the axis A, and comprise one end connected by an end piece 88 to the distributor 70 and an opposite end connected to an oil spray nozzle 86. This nozzle 86 is configured to spray oil onto the window 82 (or the sensor 83) to allow the operator to check the presence or even the pressure of the oil in the geared motor 10. It is thus understood that the window 82, the nozzle 86 and the pipe 84 extend on the same axis B in the example shown.

[0100] Advantageously, in addition to supplying oil to the nozzles 68 and the pipe 84, the distributor 70 can be configured to supply oil to the internal cavities of the plain bearings of the satellites 30. The distributor 70 is then connected to a series of end pieces 90 which are each aligned and connected to the plain bearings (figures 1 and 5).

[0101] Integrating the lubrication circuit directly into the geared motor 10 avoids adding components external to the geared motor. Using the solar 26 as an oil reservoir rather than an attached reservoir reduces the number of parts and limits the size and mass of the lubrication circuit. Furthermore, using a lubrication circuit rather than simply splashing the rotating parts of the geared motor improves the performance and efficiency of the geared motor.

Claims

CLAIMS 1. Geared motor (10) for an aircraft, this geared motor (10) comprising an electric motor (12) and a mechanical reducer (14), the reducer (14) comprising a sun gear (26) rotatable about an axis (A), a crown (28), and satellites (30) interposed between the sun gear (26) and the crown (28) and meshed with the sun gear (26) and the crown (28), the satellites (30) being carried by a planet carrier (32), the geared motor further comprising a circuit (60) for lubricating the gears of the reducer (14), characterized in that the lubrication circuit (60) is autonomous and installed inside the geared motor (10), the lubrication circuit (60) comprising a reservoir (62) of lubricating oil (66), a pump (64) located in the reservoir (62) and capable of being immersed in the lubricating oil (66) contained in the tank (62), and nozzles (68) connected to the pump (64),the pump (64) comprising a rotor (64a) which is driven in rotation by the solar (26) for drawing oil from the tank (62) and supplying oil to said nozzles (68)., 2. Geared motor (10) according to claim 1, in which the reservoir (62) is delimited by the solar (26), and preferably is formed by the solar (26).

3. Geared motor (10) according to claim 1 or 2, in which the solar (26) has a general L or C shape in axial section and comprises an internal cylindrical wall (26a) which comprises or carries external teeth (33), a radial annular wall (26b) which extends from the internal cylindrical wall (26a) towards the outside, and an external cylindrical wall (26c) which extends around the internal cylindrical wall (26a) and which is connected to the external periphery of the radial wall (26b), at least some of these walls (26a, 26b, 26c) of the solar (26) defining between them said reservoir (62).

4. A geared motor (10) according to claim 3, wherein the solar (26) further comprises an internal cylindrical rib (26d) which is located between the internal and external cylindrical walls (26a, 26c), and at a distance from the latter, and which is connected to the radial wall (26b), this rib (26d) defining the reservoir (62) with the radial wall (26b) and the internal cylindrical wall (26a).

5. Geared motor (10) according to one of the preceding claims, in which the pump (64) is connected to the nozzles (68) by an annular oil distributor (70) which extends around the axis (A).

6. Geared motor (10) according to the preceding claim, in which the pump (64) and the nozzles (68) are carried by the oil distributor (70) which comprises lugs (82) for fixing to the planet carrier (32).

7. Geared motor (10) according to one of the preceding claims, in which the nozzles (68) extend inside the crown (28), parallel to the axis (A), and are interposed circumferentially between the satellites (30).

8. Geared motor (10) according to one of the preceding claims, in which the number of nozzles (68) is equal to the number of satellites (30), each of the satellites (30) being associated with a nozzle (68) which is located between this satellite (30) and a circumferentially adjacent satellite (30).

9. Geared motor (10) according to one of claims 1 to 7, in which the number of nozzles (68) is equal to twice the number of satellites (30), each of the satellites (30) being associated with two nozzles (68) which are located circumferentially on either side of the satellite (30).

10. Geared motor (10) according to one of the preceding claims, further comprising a control system (80) for the oil in the geared motor (10), this control system (80) comprising a sensor (83) or a window (82) through which an operator can view the presence of oil, or even the oil pressure, in the geared motor (10).

11. Geared motor (10) according to claim 10, wherein the window (82) or the sensor (83) is located on a casing (42) of the geared motor (10) and is aligned with the projection axis (B) of an oil projection nozzle (86).

12. Geared motor (10) according to claim 11, dependent on claims 10 and 11 as well as claim 5 or 6, in which the oil spray nozzle (86) is carried by the planet carrier (32) and fluidly connected to the oil distributor (70), preferably by an oil pipe (84) formed in the planet carrier (32).

13. Geared motor (10) according to one of the preceding claims, in which the pump (64) is of the gerotor or vane or gear type.

14. Geared motor (10) according to one of the preceding claims, in which the planet carrier (32) is fixed and the crown (28) is movable in rotation around the axis (A).

15. Aircraft, comprising a geared motor (10) according to one of the preceding claims for driving a propulsion propeller.

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