Geared motor unit for an aircraft

Abstract

A geared motor unit (10), in particular for an aircraft, this geared motor unit (10) comprising an electric motor (12) and a mechanical reduction gear (14), the reduction gear (14) being of the planetary type and comprising a sun gear (26) rotationally movable about an axis (A), a ring gear (28) rotationally movable about the axis (A), 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) which is fixed in place, the electric motor (12) being aligned with the axis (A) and comprising a rotor (16) and a stator (18), characterized in that the ring gear (28) is coupled to an output shaft (50) which passes axially through the geared motor unit (10), the motor (12) being mounted around the reduction gear (14) which is itself mounted around this shaft (50).

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, in particular 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, CA-A1 -3 013 727, GB-A-2 590 113 and US-A1 -2010 / 007150.

[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 and are 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 turbomachine rotor, such as a propeller, can be driven by an electric motor's output shaft through a part called a wheel. In this configuration, called "direct drive," the propeller is driven at the same speed as the rotor.

[0016] When using a reducer, the output torque of the reducer is transmitted by a similar part (wheel) to the propeller. This configuration is relatively heavy and bulky, especially because the wheel forms a connecting part.

[0017] The present invention provides a solution to this problem, which is simple, effective and economical.

[0018] Summary of the invention

[0019] The invention relates to a geared motor for an aircraft, this geared motor comprising an electric motor and a mechanical reducer, the reducer being of the planetary type and comprising a sun gear rotatable about an axis and comprising external teeth, a crown gear rotatable about the axis and comprising internal teeth, and satellites interposed between the sun gear and the crown gear and meshed with the teeth of the sun gear and the crown gear, the satellites being carried by a planet carrier fixed to a casing of the geared motor, the electric motor rotating the sun gear, characterized in that the crown gear comprises an external cylindrical wall which carries the internal teeth and a radial annular wall which extends radially inwards from the external cylindrical wall and which is coupled in rotation to an output shaft which axially passes through the geared motor,and in that the planet carrier comprises an outer cylindrical wall which extends around the crown and which is fixed to the casing, and a radial annular wall which extends radially inwardly from the outer cylindrical wall and which carries the planets.,

[0020] The invention thus proposes a particular arrangement of the crown and the planet carrier with respect to each other as well as with respect to the output shaft of the geared motor, which makes it possible to reduce the overall size of the geared motor.

[0021] In the present application, radial wall means a wall perpendicular to the aforementioned axis.

[0022] The present invention is compatible:

[0023] - a single-stage or multi-stage reducer;

[0024] - straight, helical or herringbone teeth;

[0025] - any type of single-piece or cage and cage-holder type planet carrier;

[0026] - any type of satellite guide bearings, such as rolling elements or hydrodynamic.

[0027] The geared motor according to the invention may comprise one or more of the following features, taken in isolation from one another, or in combination with one another; these features having in particular the advantage of making the geared motor more compact: - the solar has in axial section a general L or C shape and comprises an internal cylindrical wall which comprises or carries the external teeth, a radial annular wall which extends radially outwards from the internal cylindrical wall, and possibly an external cylindrical wall which extends around the internal cylindrical wall and which is connected to the external periphery of the radial annular wall, the electric motor extending around the external periphery of the radial annular wall or of the external cylindrical wall;

[0028] -- the rotor is directly carried by the external periphery of the radial wall or by the external cylindrical wall;

[0029] -- the motor, and in particular the rotor, extends around the teeth of the solar;

[0030] - the sun gear has a length or dimension along the axis which is greater than or equal to a length or dimension along the axis of the sun gear teeth;

[0031] -- the rotor comprises an annular row of permanent magnets;

[0032] - the geared motor further comprises a first guide bearing for the solar, which is mounted between the solar and the planet carrier, and a second guide bearing for the solar, which is mounted between the solar and the crown;

[0033] - the first bearing has a diameter greater than the diameter of the sun gear teeth, and the second bearing has a diameter less than the diameter of the sun gear teeth;

[0034] - the first bearing is carried by the radial annular wall of the solar, and the second bearing is located radially inside the internal cylindrical wall of the solar;

[0035] - the crown has a general L or C shape in axial section and comprises an external cylindrical wall which comprises or carries the internal teeth, a radial annular wall which extends radially inwards from the external cylindrical wall, and preferably an internal cylindrical wall which extends radially inside the external cylindrical wall and which is connected to the internal periphery of the radial annular wall; - the rotor extends at least partly around the internal teeth of the crown;

[0036] - the output shaft is rotationally coupled by splines to the inner periphery of the radial annular wall of the crown or the inner cylindrical wall of the crown;

[0037] - the motor stator is fixed directly to the casing or is carried directly by the casing;

[0038] - the casing has a general L or C shape in axial section and comprises an external cylindrical wall which comprises or carries the stator, a radial annular wall which extends radially inwards from the external cylindrical wall, and preferably an internal cylindrical wall which extends radially inside the external cylindrical wall and which is connected to the internal periphery of the radial annular wall;

[0039] - the geared motor comprises a guide bearing for the output shaft, this bearing being mounted between the output shaft and the internal periphery of the radial annular wall of the casing or of the internal cylindrical wall of the casing;

[0040] - the planet carrier is fixed to the radial annular wall of the casing;

[0041] - the rotor of the electric motor is directly attached to the solar or is directly carried by the solar;

[0042] - the electric motor is mounted around the reducer which is itself mounted around the output shaft;

[0043] - the electric motor is centered on the axis and has a rotor and a stator;

[0044] - the planet carrier has a general L shape;

[0045] - the geared motor housing is a housing common to the reducer and the motor and therefore contains the reducer and the motor; the geared motor housing is therefore similar to a box.

[0046] The invention further relates to an aircraft comprising a geared motor as described above for driving a propulsion propeller.

[0047] 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:

[0048] [Fig.1] Figure 1 is a schematic perspective and axial sectional view of a geared motor according to the invention;

[0049] [Fig.2] Figure 2 is a schematic axial sectional view of the geared motor of Figure 1.

[0050] Detailed description of the invention

[0051] Figure 1 illustrates an embodiment of a geared motor 10 according to the invention, this geared motor being particularly suitable for use in an aircraft.

[0052] 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.

[0053] The geared motor 10 comprises an electric motor 12 and a mechanical reducer 14.

[0054] The electric motor 12 has an annular shape and is aligned on an axis A, which is a common axis with the reducer 14.

[0055] The electric motor 12 comprises a rotor 16 and a stator 18. In the example shown, the rotor 16 is located radially inside the stator 18.

[0056] The rotor 16 comprises an annular row of permanent magnets 20. These magnets 20 can be separated from each other by spacers 22. The number of magnets 20 can be greater than 20 or 30 for example.

[0057] The stator 18 may comprise an annular row of windings (not shown) which are formed by windings around cores 24. The number of cores 24 is for example equal to the number of permanent magnets 20.

[0058] The reducer 14 is of the planetary type, that is to say that it comprises a movable crown and a fixed planet carrier. The reducer 14 comprises a sun gear 26 movable in rotation around the axis A, a crown gear 28 movable in rotation around this axis A, and satellites 30 interposed between the sun gear 26 and the crown gear 28 and meshed with the sun gear 26 and the crown gear 28.

[0059] 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.

[0060] In the example shown, the solar 26 has a general L or C shape in axial section and comprises:

[0061] - an internal cylindrical wall 26a which comprises or carries an external toothing 33,

[0062] - a radial annular wall 26b which extends from the internal cylindrical wall 26a towards the outside,

[0063] - 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.

[0064] As seen 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.

[0065] It can be seen in the drawings that the rotor 16 can extend around the teeth 33 of the sun 26.

[0066] The sun 26 and in particular its external wall 26c may have a length L1 or dimension along the axis A which is greater than or equal to a length L2 or dimension along the axis A of the teeth 33 of the sun 26.

[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. The first bearing 34 preferably has a diameter greater than that of the teeth 33 of the sun gear 26, and the second bearing 36 has a diameter smaller than that of the teeth 33 of the sun gear 26.

[0068] 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.

[0069] In the example also shown, the crown 28 has a general L or C shape in axial section and comprises:

[0070] - an external cylindrical wall 28a which comprises or carries an internal toothing 38,

[0071] - a radial annular wall 28b which extends radially inward from the outer cylindrical wall 28a,

[0072] - and possibly an internal cylindrical wall 28c which extends radially inside the external cylindrical wall 28a and which is connected to the internal periphery of the radial wall 28b.

[0073] The rotor 16 may extend at least partly around the internal teeth 38 of the crown 28.

[0074] The geared motor 10 further comprises an output shaft 50 in the example shown, which is coupled by splines 40 to the inner periphery of the radial wall 28b or to the inner cylindrical wall 28c.

[0075] As in the example shown, the planet carrier 32 is fixed to a casing 42 of the geared motor 10.

[0076] In the example also shown, the planet carrier 32 has a general L-shape in axial section and comprises:

[0077] - an external cylindrical wall 32a, one axial end of which is fixed to the casing 42, and

[0078] - a radial annular wall 32b which extends from the external cylindrical wall 32a radially inwards and which carries the satellites 30.

[0079] The satellites 30 are interposed axially between the walls 28b and 32b.

[0080] The stator 18 of the motor 12 may be fixed directly to the casing 42 or may be carried directly by the casing 42. The casing 42 may have a general L or C shape in axial section and comprise:

[0081] - an external cylindrical wall 42a,

[0082] - a radial annular wall 42b which extends from the external cylindrical wall inwards,

[0083] - 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.

[0084] 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.

[0085] The planet carrier 32 can be fixed to the radial wall 42b of the casing 42, as in the example shown.

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) being of the planetary type and comprising a sun gear (26) rotatable about an axis (A) and comprising external teeth (33), a crown gear (28) rotatable about the axis (A) and comprising internal teeth (38), and satellites (30) interposed between the sun gear (26) and the crown gear (28) and meshed with the teeth (33, 38) of the sun gear (26) and the crown gear (28), the satellites (30) being carried by a planet carrier (32) fixed to a casing (42) of the geared motor, the electric motor (12) driving the sun gear (26) in rotation,characterized in that the crown (28) comprises an external cylindrical wall (28a) which carries the internal toothing (38) and a radial annular wall (28b) which extends radially inwards from the external cylindrical wall (28a) and which is rotatably coupled to an output shaft (50) which axially passes through the geared motor (10), and in that the planet carrier (32) comprises an external cylindrical wall (32a) which extends around the crown (28) and which is fixed to the casing (42), and a radial annular wall (32b) which extends radially inwards from the external cylindrical wall (32a) and which carries the planets (30)., 2. Geared motor (10) according to claim 1, wherein the solar (26) has a general L or C shape in axial section and comprises an internal cylindrical wall (26a) which comprises or carries the external toothing (33), a radial annular wall (26b) which extends radially outwards from the internal cylindrical wall (26a), and preferably an external cylindrical wall (26c) which extends around the internal cylindrical wall (26a) and which is connected to the external periphery of the radial annular wall (26b), the electric motor (12) extending around the external periphery of the radial annular wall (26b) or of the external cylindrical wall (26c).

3. Geared motor (10) according to claim 1 or 2, in which the solar (26) has a length (L1) or dimension along the axis (A) which is greater than or equal to a length (D2) or dimension along the axis (A) of the teeth (33) of the sun (26).

4. Geared motor (10) according to one of the preceding claims, further comprising a first bearing (34) for guiding the sun (26), which is mounted between the sun (26) and the planet carrier (32), and a second bearing (36) for guiding the sun (26), which is mounted between the sun (26) and the ring gear (28).

5. Geared motor (10) according to claim 4, in which the first bearing (34) has a diameter greater than the diameter of the teeth (33) of the sun gear (26), and the second bearing (36) has a diameter less than the diameter of the teeth (33) of the sun gear (26).

6. Geared motor (10) according to claim 4 or 5, dependent on claim 2, in which the first bearing (34) is carried by the radial annular wall (26b) of the solar (26), and the second bearing (36) is located radially inside the internal cylindrical wall (26c) of the solar (26).

7. Geared motor (10) according to one of the preceding claims, in which the crown (28) has a general L or C shape in axial section and comprises an external cylindrical wall (28a) which comprises or carries the internal toothing (38), a radial annular wall (28b) which extends radially inwards from the external cylindrical wall (28a), and preferably an internal cylindrical wall (28c) which extends radially inside the external cylindrical wall (28a) and which is connected to the internal periphery of the radial annular wall (28b).

8. Geared motor (10) according to claim 7, wherein the electric motor (12) comprises a rotor (16) which extends at least partly around the internal teeth (38) of the crown (28).

9. Geared motor (10) according to claim 7 or 8, wherein the output shaft (50) is rotationally coupled by splines (40) to the inner periphery of the radial annular wall (28b) of the crown (28) or of the inner cylindrical wall (28c) of the crown (28).

10. Geared motor (10) according to one of the preceding claims, in which the stator (18) of the motor (14) is fixed directly to the casing (42) or is carried directly by the casing (42).

11. Geared motor (10) according to claim 10, in which the casing (42) has a general L or C shape in axial section and comprises an external cylindrical wall (42a) which comprises or carries the stator (18), a radial annular wall (42b) which extends radially inwards from the external cylindrical wall (42a), and preferably an internal cylindrical wall (42c) which extends radially inside the external cylindrical wall (42a) and which is connected to the internal periphery of the radial annular wall (42b).

12. Geared motor (10) according to claim 11, comprising 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 annular wall (42b) of the casing (42) or of the internal cylindrical wall (42c) of the casing (42).

13. Geared motor (10) according to claim 11 or 12, in which the planet carrier (32) is fixed to the radial annular wall (42b) of the casing (42).

14. Geared motor (10) according to one of the preceding claims, in which the electric motor (12) comprises a rotor (16) which is directly fixed to the solar (26) or which is directly carried by the solar (26).

15. Geared motor (10) according to one of the preceding claims, in which the electric motor (12) is mounted around the reducer (14) which is itself mounted around the shaft (50).

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

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