GEAR MOTOR FOR AN AIRCRAFT
The geared motor for aircraft addresses bulkiness by integrating the rotor directly with the sun gear, achieving reduced size and mass through a novel planetary-type reducer configuration and bearing systems, improving compactness and efficiency.
Patent Information
- Application Number
- FR2023012787
- Authority / Receiving Office
- FR · FR
- Patent Type
- Patents
- Current Assignee / Owner
- Filing Date
- 2023-11-21
- Publication Date
- 2026-02-20
- Estimated Expiration
- 2043-11-21
AI Technical Summary
Existing geared motors for aircraft are bulky and heavy due to intermediate connecting parts between the electric motor and the mechanical reducer, which hinders compactness and efficiency.
A geared motor design where the rotor is directly fixed to or supported by the sun gear, eliminating intermediate connecting parts, and incorporating a planetary-type mechanical reducer with a movable sun and ring gear, along with specific bearing configurations for enhanced compactness.
The design reduces the size and mass of the geared motor, enhancing its compactness and efficiency while maintaining compatibility with various reducer types and bearing systems.
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Abstract
Description
Title of the invention: GEAR MOTOR FOR AN AIRCRAFT Technical field of the invention
[0001] The present invention relates in particular to a geared motor, especially for an aircraft, as well as to an aircraft comprising such a geared motor. Technical Downstream Plan
[0002] The state of the art includes in particular documents FR-A1-2 987 416, FR-A1-2 853 382, FR-A1-3 041 054, FR-A1-3 073 915, FR-A1-3 084 428.
[0003] The combination of an electric motor and a mechanical reducer forms a geared motor.
[0004] 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.
[0005] New generations of turbofan engines, particularly those with a high bypass ratio, include a mechanical gearbox to drive the shaft of a fan. Typically, the purpose of the gearbox is to transform the high rotational speed of the power turbine shaft into a slower rotational speed for the fan-driving shaft.
[0006] Such a reduction gear comprises a central pinion, called the sun gear, a ring gear, and pinions called planet gears, which mesh between the sun gear and the ring gear. The planet gears are held by a frame called a planet carrier. The sun gear, ring gear, and planet carrier are planetary 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 spaced on the same operating diameter around the axis of the planet gears. These axes are parallel to the longitudinal axis of the turbomachine.
[0007] Several gearbox architectures exist. In the state of the art of turbofan engines, gearboxes are of the planetary or epicyclic type. In other similar applications, there are so-called differential or "compound" architectures.
[0008] - on a planetary reducer, the planet carrier s is fixed and the ring constitutes the output shaft of the device which rotates in the opposite direction to the solar.
[0009] - on an epicyclic reducer, the ring gear is fixed and the planet carrier constitutes the output shaft of the device which rotates in the same direction as the solar panel.
[0010] - on a differential reducer, no element is fixed for rotation. The ring rotates in the opposite direction to the solar panel and the satellite carrier.
[0011] Reducers can be composed of one or more meshing stages. This meshing is achieved in various ways such as by contact, by friction, or by magnetic field. There are several types of contact meshing such as with straight or herringbone teeth.
[0012] A turbomachine rotor, such as a propeller, can be driven by an output shaft of an electric motor via a component called a wheel. In this configuration, called "direct drive," the propeller is driven at the same speed as the rotor.
[0013] When using a gearbox, the output torque of the gearbox is transmitted to the propeller by a similar component (wheel). This configuration is relatively heavy and bulky, particularly because of the wheel, which acts as a connecting piece.
[0014] The present invention proposes a solution to this problem, which is simple, effective and economical. Summary of the invention
[0015] 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 movable sun in rotation around an axis, a movable ring in rotation around the axis, and satellites intercalated between the sun and the ring and meshed with the sun and the ring, the satellites being carried by a satellite carrier which is fixed, the electric motor being centered on the axis and comprising a rotor and a stator, characterized in that the rotor is directly fixed to the sun or is directly carried by the sun.
[0016] The distinctive feature of the invention lies in the fact that the rotor is directly attached to the solar panel or supported by the solar panel; that is, there is no intermediate connecting or coupling part as in the prior art. This is particularly advantageous for reducing the size and mass of the geared motor, and thus increasing its compactness.
[0017] The present invention is compatible with: - of a single-stage or multi-stage reducer; - of straight, helical or chevron teeth; - of any type of one-piece satellite carrier or of the cage and cage carrier type; - of all types of satellite guidance bearings, such as rolling element bearings or hydrodynamic.
[0018] The geared motor according to the invention may comprise one or more of the following features, taken individually or in combination with each other; these features having in particular the advantage of making the geared motor more compact: • The solar element, in axial section, generally has an L or C shape and includes an internal cylindrical wall that comprises or carries teeth. external, a radial annular wall extending radially outwards from the internal cylindrical wall, and optionally an external cylindrical wall extending around the internal cylindrical wall and connected to the external periphery of the radial annular wall, the rotor being directly fixed to the external periphery of the radial annular wall or to the external cylindrical wall, and being directly supported by the external periphery of the radial annular wall or by the external cylindrical wall; the rotor extends around the teeth of the solar panel; the solar element has a length or dimension along the axis which is greater than or equal to a length or dimension along the axis of the teeth of the solar element; the rotor includes an annular row of permanent magnets; the geared motor further includes a first solar guide bearing, which is mounted between the solar and the satellite carrier, and a second solar guide bearing, which is mounted between the solar and the ring; the first bearing has a diameter greater than the diameter of the teeth of the solar, and the second bearing has a diameter less than the diameter of the teeth of the solar; the first bearing is supported by the radial annular wall of the solar, and the second bearing is located radially inside the internal cylindrical wall of the solar; the crown has in axial section a general L or C shape and comprises an external cylindrical wall which includes or carries 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 partially around the internal teeth of the crown; the geared motor includes an output shaft which is rotationally coupled by splines to the inner periphery of the radial annular wall of the ring or the inner cylindrical wall of the ring; the satellite carrier is fixed to a housing of the geared motor, the motor stator being fixed directly to the housing or carried directly by the housing; The housing, in axial section, has a general L or C shape and comprises an outer cylindrical wall that includes or carries the stator, a radial annular wall extending radially inwards from the outer cylindrical wall, and preferably an inner cylindrical wall extending radially inside the external cylindrical wall and which is connected to the internal periphery of the radial annular wall; • the geared motor further includes a guide bearing for the output shaft, this bearing being mounted between the output shaft and the inner periphery of the radial annular wall of the housing or of the inner cylindrical wall of the housing; • the satellite carrier is fixed to the radial annular wall of the housing;
[0019] — the solar element includes external teeth,
[0020] — the crown includes an internal dentition.
[0021] The invention further relates to an aircraft comprising a geared motor as described above for driving a propulsion propeller. Brief description of the figures
[0022] Other features and advantages will become apparent from the following description of a non-limiting embodiment of the invention with reference to the accompanying drawings in which:
[0023] [Fig-1] [Fig.1] is a schematic perspective and axial section view of a geared motor according to the invention;
[0024] [Fig.2] [Fig.2] is a schematic axial cross-sectional view of the geared motor of [Fig.1]. Detailed description of the invention
[0025] Fig. 1 illustrates an embodiment of a geared motor 10 according to the invention, this geared motor being particularly suitable for use in an aircraft.
[0026] 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.
[0027] The geared motor 10 comprises an electric motor 12 and a mechanical reducer 14.
[0028] The electric motor 12 has an annular shape and is aligned on an axis A, which is a common axis with the reducer 14.
[0029] 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.
[0030] The rotor 16 includes 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.
[0031] The stator 18 may include 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.
[0032] The reducer 14 is of the planetary type, that is to say, it includes a movable ring and a fixed planet carrier.
[0033] The reducer 14 includes a solar 26 movable in rotation around the axis A, a ring 28 movable in rotation around this axis A, and satellites 30 intercalated between the solar 26 and the ring 28 and meshed with the solar 26 and the ring 28.
[0034] The satellites 30 are carried by a fixed satellite carrier 32. Conventionally, each of the satellites 32 is mounted on an axis that forms a plain bearing or around which a roller bearing is mounted.
[0035] In the example shown, the solar element 26 has a general L or C shape in axial section and comprises:
[0036] - an internal cylindrical wall 26a which includes or carries external teeth 33,
[0037] - a radial annular wall 26b extending from the internal cylindrical wall 26a outwards,
[0038] - and possibly an external cylindrical wall 26c which extends around the wall internal cylindrical 26a and which is connected to the external periphery of the radial wall 26b.
[0039] As can be 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.
[0040] It can be seen in the drawings that the rotor 16 can extend around the teeth 33 of the solar 26.
[0041] The solar 26 and in particular its outer wall 26c can 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 toothing 33 of the solar 26.
[0042] Advantageously, the geared motor 10 includes a first bearing 34 for guiding the solar 26, which is mounted between the solar 26 and the satellite carrier s 32, and a second bearing 36 for guiding the solar 26, which is mounted between the solar 26 and the ring 28.
[0043] The first bearing 34 preferably has a diameter DI greater than that D2 of the teeth 33 of the solar 26, and the second bearing 36 has a diameter D3 less than that D2 of the teeth 33 of the solar 26.
[0044] In the example shown, the first bearing 34 is supported by the radial wall 26b, and the second bearing 36 is located inside the internal cylindrical wall 26c.
[0045] In the example also shown, the crown 28 has, in axial section, a general L- or C-shaped form and comprises:
[0046] - an external cylindrical wall 28a which includes or carries internal teeth 38,
[0047] - a radial annular wall 28b extending from the external cylindrical wall 28a inward,
[0048] - 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.
[0049] The rotor 16 can extend at least partially around the internal teeth 38 of the crown 28.
[0050] The geared motor 10 further includes an output shaft 50 in the example shown, which is rotationally coupled by splines 40 to the inner periphery of the radial wall 28b or to the inner cylindrical wall 28c.
[0051] As in the example shown, the satellite carrier 32 is fixed to a housing 42 of the geared motor 10.
[0052] In the example also shown, the satellite carrier 32 has a general L-shaped profile in axial section and comprises:
[0053] - an external cylindrical wall 32a, one axial end of which is fixed to the housing 42, and
[0054] - a radial annular wall 32b extending from the external cylindrical wall 32a inwards and which carries the 30 satellites.
[0055] The satellites 30 are axially intercalated between the walls 28b and 32b.
[0056] The stator 18 of the motor 12 can be fixed directly to the housing 42 or carried directly by the housing 42.
[0057] The housing 42 may have a general L-shaped or C-shaped shape in axial section and comprise:
[0058] - an external cylindrical wall 42a,
[0059] - a radial annular wall 42b extending from the outer cylindrical wall towards the interior,
[0060] - 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.
[0061] The geared motor 10 may include a bearing 44 for guiding the output shaft 50, this bearing 44 being mounted between the output shaft 50 and the inner periphery of the radial wall 42b or the inner cylindrical wall 42c of the housing 42.
[0062] The satellite carrier 32 can be fixed to the radial wall 42b of the housing 42, as in the example shown.
Claims
Demands
1. Geared motor (10) for an aircraft, said geared motor (10) comprising an electric motor (12) and a mechanical gearbox (14), the gearbox (14) being of the planetary type and comprising a sun gear (26) movable in rotation about an axis (A), a ring gear (28) movable in rotation about the axis (A), and planet gears (30) interposed between the sun gear (26) and the ring gear (28) and meshed with the sun gear (26) and the ring gear (28), the planet gears (30) being carried by a planet carrier (32) which is fixed, the electric motor (12) being centered on the axis (A) and comprising a rotor (16) and a stator (18), characterized in that the sun gear (26) has in axial section a general L- or C-shaped shape and comprises an internal cylindrical wall (26a) which includes or carries external teeth (33), and a wall radial annular (26b) which extends radially outwards from the internal cylindrical wall (26a),the rotor (16) of the electric motor (12) being directly fixed to the outer periphery of the radial annular wall (26b) of the solar panel (26) or being directly supported by the outer periphery of the radial annular wall (26b) of the solar panel (26).
2. Geared motor (10) according to claim 1, wherein the solar (26) further comprises an external cylindrical wall (26c) at the external periphery of the radial annular wall (26b), the rotor (16) being directly fixed to the external cylindrical wall (26c), or being directly carried by the external cylindrical wall (26c).
3. Geared motor (10) according to claim 1 or 2, wherein the rotor (16) extends around the teeth (33) of the solar (26).
4. Geared motor (10) according to any one of claims 1 to 3, wherein 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 solar (26).
5. Geared motor (10) according to any one of the preceding claims, wherein the rotor (16) comprises an annular row of permanent magnets (20).
6. Geared motor (10) according to any one of the preceding claims, further comprising a first bearing (34) for guiding the solar element (26), which is mounted between the solar element (26) and the satellite carrier (32), and a second bearing (36) for guiding the solar (26), which is mounted between the solar (26) and the crown (28).
7. Geared motor (10) according to claim 6, wherein the first bearing (34) has a diameter (Dl) greater than the diameter (D2) of the teeth (33) of the solar (26), and the second bearing (36) has a diameter (D3) less than the diameter of the teeth (33) of the solar (26).
8. Geared motor (10) according to claim 6 or 7, wherein 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).
9. Geared motor (10) according to any one of the preceding claims, wherein the ring (28) has in axial section a general L- or C-shaped shape and comprises an external cylindrical wall (28a) which includes or carries internal teeth (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).
10. Geared motor (10) according to claim 9, in which the rotor (16) extends at least partially around the internal teeth (38) of the ring gear (28).
11. Geared motor (10) according to claim 9 or 10, comprising an output shaft (50) which is rotationally coupled by splines (40) to the inner periphery of the radial annular wall (28b) of the ring (28) or of the inner cylindrical wall (28c) of the ring (28).
12. Geared motor (10) according to any one of the preceding claims, wherein the planet carrier (32) is fixed to a housing (42) of the geared motor, the stator (18) of the motor (14) being fixed directly to the housing (42) or carried directly by the housing (42).
13. Geared motor (10) according to claim 12, wherein the housing (42) has in axial section a general L- or C-shaped shape and comprises an external cylindrical wall (42a) which includes 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).
14. Geared motor (10) according to claim 13, depending on claims 11 and 12, further comprising a bearing (44) for guiding the output shaft (50), this bearing (44) being mounted between the output shaft (50) and the inner periphery of the radial annular wall (42b) of the housing (42) or of the inner cylindrical wall (42c) of the housing (42).
15. Geared motor (10) according to claim 13 or 14, wherein the planet carrier s (32) is fixed to the radial annular wall (42b) of the housing (42).
16. Aircraft, comprising a geared motor (10) according to any one of the preceding claims for driving a propulsion propeller.