Hover-capable aircraft

Abstract

A hovering aircraft (1) is described, comprising a motor assembly (10); a rotor (5) connected to the motor assembly (10); a drive shaft (11) rotatable about a first axis (B) and adapted to drive the rotor (5); and a transmission device (9) inserted between the motor assembly (10) and the rotor (5), the transmission device comprising a planetary gear (21) formed of: a sun gear (7) rotatable about a second axis (D); a crown gear (17) fixed in an angular direction; and two satellite gears (19) meshing with the crown gear (17) and the sun gear (15) respectively and rotatable about a corresponding third axis (I), which... It can also rotate about a second axis (D); and a satellite wheel carrier (30) that can rotate about the second axis (D) and includes two first pins (32), the satellite wheel (19) being able to rotate about a corresponding third axis (E) relative to the first pins (32); the transmission device (9) includes an interface (50) that is integral with the satellite wheel carrier (30) in an angular direction about the second axis (D) and integral with the drive shaft (11) in an angular direction about the first axis (B); the interface (50) is connected to the satellite wheel carrier (30) and the drive shaft (11) to allow angular displacement between the second axis and a portion of the interface (50).

Description

[0001] Cross-reference to related applications

[0002] This patent application claims priority to European Patent Application No. 21162130.5, filed on March 11, 2021, the entire disclosure of which is incorporated herein by reference. Technical Field

[0003] This invention relates to an aircraft capable of hovering, such as a helicopter or a vertical takeoff and landing (VTOL) aircraft or helicopter. Background Technology

[0004] As is well known, helicopters typically have a transmission system adapted to transmit motion from one or more turbines to the main rotor and / or tail rotor, and / or from the turbines to multiple auxiliary devices (i.e., responsible for supplying energy required for the operation of onboard equipment, for example).

[0005] Helicopters generate the lift they need by rotating the blades of their main rotor. Therefore, helicopters can land / take off without requiring horizontal speed and using very small surfaces. Furthermore, helicopters are capable of hovering and flying at relatively low altitudes and speeds, making them particularly maneuverable and suitable for demanding maneuvering tasks such as those performed in mountainous or maritime rescue operations.

[0006] However, helicopters have inherent limitations in terms of maximum operating altitude (approximately 20,000 feet) and maximum operating speed (not exceeding 150 knots).

[0007] In order to meet the need for an aircraft that can provide the same maneuverability and comfort as a helicopter while overcoming the inherent limitations mentioned above, vertical takeoff and landing (VTOL) aircraft and helicopters are known.

[0008] More specifically, known types of vertical takeoff and landing (VTOL) aircraft basically include:

[0009] - The fuselage extending along the first longitudinal axis;

[0010] - A pair of cantilevered half-wings extending from corresponding, opposite portions of the fuselage, the half-wings having corresponding free ends opposite the fuselage and aligned along a second transverse axis substantially orthogonal to the first longitudinal axis;

[0011] - A pair of nacelles carrying the corresponding motors and fixed relative to the associated half-wing; and

[0012] - A pair of rotors that can rotate around a corresponding third axis and are operably connected to a corresponding motor.

[0013] Each rotor comprises, in a known manner, a drive shaft capable of rotating about an associated third axis and multiple blades hinged to the drive shaft, which are circumferentially distributed around the free end of the drive shaft extending from the corresponding nacelle.

[0014] Vertical takeoff and landing (VTOL) aircraft can also selectively present:

[0015] - An "aircraft" configuration in which the rotors are arranged such that the corresponding third axis is substantially parallel to the first axis of a vertical takeoff and landing reversible aircraft; or

[0016] - A “helicopter” configuration in which the rotor is arranged such that the corresponding third axis is substantially perpendicular to and transverse to the first axis of the vertical takeoff and landing reversing aircraft.

[0017] Because it can tilt its rotor, a vertical takeoff and landing (VTOL) aircraft can take off and land like a helicopter, that is, take off and land in a direction substantially perpendicular to the aircraft's first longitudinal axis, without the need for a runway.

[0018] In addition, vertical takeoff and landing (VTOL) aircraft can take off and land on rugged terrain without producing noise levels incompatible with urban residential areas.

[0019] In addition, vertical takeoff and landing (VTOL) aircraft can hover when configured as helicopters.

[0020] Furthermore, when configured as an aircraft structure, a vertical takeoff and landing (VTOL) aircraft can achieve and maintain a cruising speed of approximately 250-300 knots and a flight altitude of approximately 30,000 feet.

[0021] This cruise speed is much higher than the maximum cruise speed of approximately 150 knots for helicopters.

[0022] Similarly, this altitude is much higher than the typical altitude of a helicopter and allows vertical takeoff and landing (VTOL) aircraft configured as aircraft structures to avoid the cloud cover and atmospheric disturbances characteristic of lower altitudes.

[0023] In addition to components common to known helicopters (such as a main rotor with a vertical axis), helicopters (also known as "compound helicopters," such as the Eurocopter X-3 aircraft) also include a pair of half-wings that cantilever from the corresponding parts of the helicopter fuselage along a fifth lateral axis, which is substantially orthogonal to the longitudinal axis of the aircraft and the axis of rotation of the main rotor.

[0024] More specifically, each half-wing carries a corresponding propeller, which comprises, in a known manner, a drive shaft operable by an associated motor and multiple blades hinged to the drive shaft.

[0025] In particular, each drive shaft can rotate about a related sixth axis that is substantially parallel to the helicopter's longitudinal axis (i.e., horizontal axis).

[0026] Therefore, helicopters can take off and land vertically via the main rotor in the same way as VTOL aircraft, and fly forward via the propeller and the aforementioned half-wing.

[0027] During forward flight, the main rotor spins while the propeller generates thrust.

[0028] Whether it's a helicopter, a vertical takeoff and landing aircraft, or a tractor-trailer, these aircraft all include one or more mechanical transmissions adapted to transmit motion from one or more turbines to the rotor.

[0029] Such mechanical transmissions typically employ one or more planetary gears within a reduction chain that is suitable for transmitting power to the actuator shaft of the main rotor with sufficient torque and speed.

[0030] In its simplest form, the aforementioned planetary gears essentially consist of:

[0031] - Defined as the first gear of the sun gear, which can rotate about a fixed seventh axis;

[0032] - Defined as a fixed second gear of the crown wheel, having an eighth axis coinciding with the fourth axis; and

[0033] - Defined as multiple gears of a satellite gear, which mesh with the sun gear and the crown gear and are capable of rotating about a corresponding movable ninth axis.

[0034] The planetary gear also includes a satellite wheel carrier that can rotate around the seventh axis and is connected to the satellite wheel.

[0035] More precisely, the satellite wheel can rotate about the corresponding ninth axis relative to the corresponding pin of the satellite wheel carrier, and describes the revolution motion about the seventh axis that is integral with the satellite wheel carrier.

[0036] The relative rotation between the pins of the satellite and the satellite wheel carrier is provided by corresponding rolling bearings.

[0037] Each rolling bearing includes:

[0038] - The first ring, which is integral with the corresponding pin in the angular direction and defines the first raceway;

[0039] - A second ring, which is integral with the corresponding satellite wheel in the angular direction and defines a second raceway; and

[0040] - Multiple rolling bodies that roll on the first and second raceways, preferably double-crowned cylindrical rollers.

[0041] The crown of the same bearing is symmetrically arranged on the corresponding side with respect to the corresponding satellite wheel in a plane of symmetry orthogonal to the relevant ninth axis.

[0042] In known implementations, mechanical power is transmitted via the sun gear to the planetary gears and then to the satellite gear carrier.

[0043] The satellite wheel frame also has a power take-off shaft that connects to the rotor shaft to transmit the correct drive torque to the rotor shaft at the correct angular velocity.

[0044] The satellite wheel frame must have an asymmetrical shape relative to a plane orthogonal to the seventh axis.

[0045] This is because the power output shaft that connects the drive shaft of the main rotor to the satellite wheel carrier cannot be placed on the same plane of symmetry as the satellite wheel, which is orthogonal to the seventh axis, because there are sun wheels and crown wheels located radially inside and outside the satellite wheel, respectively.

[0046] Due to this geometric asymmetry of the satellite wheel frame, its stiffness is necessarily asymmetrical relative to the plane orthogonal to the seventh axis.

[0047] Under operating conditions, the sun gear transmits a considerable amount of driving torque to the satellite wheel carrier.

[0048] Due to the asymmetrical stiffness of the satellite wheel carrier, the transmission of driving torque from the sun gear to the satellite wheel carrier will produce differential deformation in the radial direction on the cylindrical rollers of each satellite wheel.

[0049] These differential deformations cause the pin to tilt, and the pin's axis no longer completely coincides with the seventh axis of rotation of the satellite gear relative to the fifth axis of rotation of the sun gear, thus having a significant impact on the normal operation of the planetary gears.

[0050] In fact, cylindrical roller bearings and gears operate under high contact pressure, and their operation is optimal when the aforementioned seventh, eighth, and ninth axes are perfectly aligned with each other.

[0051] More precisely, when the seventh, eighth, and ninth axes are perfectly aligned, the curve of the contact pressure between the cylindrical rollers relative to the axial coordinate of the cylindrical rollers is a substantially flat curve that decreases at the axial end.

[0052] Conversely, when there is a deviation between the corresponding seventh, eighth, and ninth axes, the aforementioned curves showing the variation in contact pressure exhibit values ​​that are significantly higher than in the case of perfect alignment. A similar phenomenon occurs with the teeth of the satellite gears meshing with the sun gear and crown gear. This leads to a reduction in the lifespan and operational performance of the planetary gears.

[0053] There is a need in this field to suppress the deformation of the satellite wheel support under load in order to improve the life and operating performance of the planetary gears.

[0054] US2020 / 0292059 describes a planetary gear having a plurality of satellite gears carried by a planetary gear carrier. The planetary gear carrier includes a support and a plurality of pins carried by the support. Each pin has a connecting section arranged on an opposite side of the support. Each satellite gear is arranged about a corresponding connecting section and has rotational freedom relative to the connecting section. A retaining element is carried by the pins and connects them. Each satellite gear is arranged in a region between the support and the retaining element. Each pin can move relative to the retaining element in a limited manner.

[0055] US2020 / 0332858 describes a planetary gear comprising a sun gear and a plurality of satellite gears housed in a cage that supports bearings on the satellite gears and a lubrication system for the sun gear.

[0056] The cage further includes:

[0057] - Multiple receiving elements, which are engaged by axial arms fixed to the body;

[0058] - Finger-like elements, radially passing through the associated receiving element and adapted to guide the rotation of the connector carried by an arm; and

[0059] - A lubrication device for lubricating joints, carried by a finger-shaped component.

[0060] US2009 / 0111639 describes a planetary gear in which each satellite gear is supported on an associated pin by a combination of a radially inner spherical support and a radially outer cylindrical roller bearing. The spherical support allows the cylindrical roller bearing to oscillate to compensate for any angular displacement between the satellite gear and the associated pin of the planetary gear carrier and to allow its associated rotation.

[0061] US2020 / 0011411 describes a planetary gear with a spherical support and a cylindrical roller bearing for each satellite gear. The spherical support allows the cylindrical roller bearing to oscillate to compensate for any angular displacement between the satellite gear and the associated pin of the planetary gear carrier and to allow its associated rotation.

[0062] For each satellite wheel, the planetary gear also includes an element that includes a surface that radially defines a radial inner raceway for the cylindrical rollers and a radial inner surface associated with the outer surface of the spherical element.

[0063] US5466198 discloses a gear drive system employing a planetary gear train to transmit torque and rotational motion from their source to a bladed propeller or other device requiring torque and rotational motion. A pivotable joint device connects the planetary gear carrier to a rotating or static torque frame in a manner that isolates the planetary gear carrier from torsional deflection and its detrimental effects. Summary of the Invention

[0064] The purpose of this invention is to provide an aircraft that can meet the above requirements in a simple and economical manner.

[0065] The above objective is achieved by the hovering aircraft claimed in claim 1. Attached Figure Description

[0066] Other features and advantages of the invention will become clear from the following detailed description provided by way of non-limiting examples and with reference to the accompanying drawings, in which:

[0067] - Figure 1 A side view of a hovering aircraft, particularly a vertical takeoff and landing reversing aircraft, is shown according to the present invention.

[0068] - Figure 2 yes Figure 1 The planetary reduction stage of the aircraft's transmission system along Figure 1 The longitudinal section of line II-II;

[0069] - Figure 3 yes Figure 2 A top view of the planetary deceleration stage;

[0070] - Figure 4 yes Figure 2 and Figure 3 An exploded view of the satellite wheel frame of the main reduction stage; some parts have been removed for clarity.

[0071] - Figure 5 yes Figures 2 to 4 A 3D view of the satellite wheel frame of the deceleration stage; some parts have been removed for clarity.

[0072] - Figure 6 yes Figures 2 to 5 Enlarged cross-section of some components of the planetary gear in the transmission device;

[0073] - Figure 7 yes Figures 2 to 6 Exploded views of some components of the transmission device; and

[0074] - Figure 8 yes Figures 2 to 7 A schematic diagram of the elastic deformation of the interface component of the transmission device. Detailed Implementation

[0075] Reference Figure 1 The attached figure, labeled 1, indicates an aircraft capable of hovering, which in the case shown is a vertical takeoff and landing (VTOL) aircraft.

[0076] Vertical takeoff and landing reversing aircraft mainly include:

[0077] - Fuselage 2 with longitudinally extending axis A;

[0078] - A pair of half-wings 3 extending laterally along axis A from corresponding parts of the fuselage 2;

[0079] - A pair of nacelles 4 that house the associated motor 10 and are fixed relative to the corresponding half-wing 3; and

[0080] - A pair of rotors 5 that are operably connected to the corresponding motor.

[0081] The fuselage 2 also includes a nose 12 and a tail 13 located at the front and opposite each other along axis A.

[0082] Each half-wing 3 includes a free end opposite to the fuselage 2. The ends of each half-wing 3 are aligned along an axis E orthogonal to axis A.

[0083] It should be noted that the terms “front,” “tail,” “longitudinal,” “lateral,” “above,” and “below” used in this specification refer to the normal direction of the forward movement of the vertical takeoff and landing reversing aircraft 1.

[0084] As a non-limiting example, the aforementioned motor 10 may be a multi-stage turbine motor of the turboshaft type, an internal combustion motor, or a hybrid (electric-thermal) power system.

[0085] More specifically, each rotor 5 basically includes:

[0086] - A drive shaft 11 that can rotate around axis B;

[0087] - The rotor hub 7, driven by drive shaft 11, rotates; and

[0088] - Multiple blades 8 are hinged to the rotor hub 7.

[0089] Rotor 5 can tilt about axis C relative to the associated half-wing 3 and associated nacelle 4.

[0090] Axis C is transverse to axes A and B.

[0091] Axis C is also parallel to axis E.

[0092] The vertical takeoff and landing reversing aircraft 1 can be selectively arranged as follows:

[0093] - Helicopter structure ( Figure 1 (As can be seen in the image), where the axis B of rotor 5 is orthogonal to axes A and C; and

[0094] - An “aircraft” configuration (not shown) in which the axis B of rotor 5 is parallel to axis A and orthogonal to axis C.

[0095] For each rotor 5, the vertical takeoff and landing reversing aircraft 1 also includes a main drive unit 9, which is adapted to transmit motion from one or more motors 10 to the drive shaft 11 of the associated rotor 5 (only when...). Figure 1 (Illustrated in the diagram).

[0096] Since the transmission devices 9 are identical to each other, reference will be made below to the individual rotor 5 and the associated transmission device 9.

[0097] The transmission 9 also includes an end stage 20 formed essentially by planetary gears 21. Figure 3 The planetary gear 21 transmits power to the drive shaft 11 of the rotor 5 with the correct torque and angular velocity values.

[0098] In the case shown, planetary gear 21 is a gearbox.

[0099] Especially referencing Figure 2 Planetary gear 21 basically includes:

[0100] - Sun gear 15, which includes a plurality of teeth 16, is rotatable about axis D and is operably connected to the input shaft (not shown) of stage 20;

[0101] - Crown wheel 17, fixed in the angular direction relative to axis D; and

[0102] - Multiple gears that perform the functions of individual satellite wheels 19, which are rotatable about a corresponding axis I parallel to axis D and mesh with sun gear 15 and crown gear 17.

[0103] In the case shown, the diameter of the crown wheel 17 is larger than the diameter of the sun wheel 15.

[0104] Crown wheel 17 surrounds satellite wheel frame 30.

[0105] Furthermore, the crown wheel 17 is supported by a fixed structure, which is only partially shown in the accompanying drawings.

[0106] Planetary gear 21 also includes a satellite wheel carrier 30 that can rotate about axis D. Figure 3 (Schematic illustration) The satellite wheel frame 30 is directly connected to the drive shaft 11 of the rotor 5 and connected to the satellite wheel 19.

[0107] Specifically, each satellite wheel 19 rotates relative to the satellite wheel carrier 30 about its axis I, and describes a revolution motion around the axis D integrally with the satellite wheel carrier 30.

[0108] Furthermore, mechanical power enters the planetary gear 21 at the sun gear 15 and exits the planetary gear 21 at the satellite wheel carrier 30 along the direction of the drive shaft 11 of the rotor 5 with the correct torque value and rotation speed.

[0109] Specifically, the satellite wheel frame 30 includes ( Figure 2 , Figure 3 , Figure 6 and Figure 7 ):

[0110] - A plurality of pins 32 extending along a corresponding axis I, and corresponding satellite wheels 19 rotatably mounted on the plurality of pins 32 about the corresponding axis I; and

[0111] - Multiple rolling bearings 40 are radially inserted between the corresponding pins 32 and the satellite wheel 19.

[0112] More specifically, each bearing 40 is adapted to support a corresponding satellite wheel 19, which is rotatable about a corresponding axis I on a corresponding pin 32.

[0113] Each bearing 40 includes:

[0114] - Ring 41, which is fixed in an angular direction relative to the associated pin 32 and defines the raceway 42;

[0115] - Ring 43, which is fixed in an angular direction relative to the associated satellite wheel 19, is arranged radially outward relative to the associated axis I at the outermost point of ring 41, and defines raceway 44 facing the associated raceway 42; and

[0116] - Multiple rolling bodies 45 that roll on the relevant raceways 42, 44.

[0117] exist Figure 2 In the case shown, the body 45 of each bearing 40 is a cylindrical roller coaxial with the associated axis I, and these cylindrical rollers form two rows arranged around the associated axis I and spaced apart parallel to the associated axis I.

[0118] Satellite wheel 19 has a symmetry plane P that is orthogonal to the corresponding axis I.

[0119] Each crown of the rolling body 45 is arranged on the corresponding side of the plane of symmetry P.

[0120] In addition, the transmission device 9 includes an interface 50 inserted between the satellite wheel frame 30 and the drive shaft 11. The interface 50 is rotatable integrally with the satellite wheel frame 30 about axis D and integrally with the drive shaft 11 about axis B. The interface 50 is connected to the satellite wheel frame 30 and the drive shaft 11 to allow at least a portion of the interface 50 to tilt relative to the satellite wheel frame 30.

[0121] More specifically, the interface 50 is at least partially capable of revolving around a pair of axes F, G (orthogonal to each other and orthogonal to axis I). Figure 6 It is hinged to the satellite wheel frame 30 in an inclined manner relative to the satellite wheel frame 30.

[0122] In other words, the connection between the satellite wheel carrier 30 and the interface member 50 is torsional rigid relative to axes D and B, but allows the aforementioned portion of the interface member 50 to deflect relative to the satellite wheel carrier 30 about axes F and G.

[0123] In this way, the torque transmitted from the sun gear 15 to the satellite gear 30 does not cause the axis I to deviate relative to the axes D and B, but causes the interface 50 to undergo elastic deformation.

[0124] More specifically, such as Figure 8 As shown, when subjected to torque transmitted by the satellite wheel frame 30, the interface component 50 exhibits asymmetrical deformation relative to the same plane P.

[0125] This is due to the geometric asymmetry of the interface component 50 relative to the plane P and its constraint to the axis 11.

[0126] In contrast, the satellite wheel frame 30 exhibits a deformation that is symmetrical with respect to the midplane P, which is orthogonal to the axis D.

[0127] Preferably, the interface component 50 further includes:

[0128] - Radial inner end edge 52, which internally defines a radial inner seat 51, through which the shaft 11 is secured by a key;

[0129] - Radial outer edge 54; and

[0130] - Multiple spokes 53 spaced equidistant from each other, extending radially between edges 52, 54. In particular, the spokes 53 diverge from each other toward the satellite wheel frame 30 from edge 52 toward edge 54.

[0131] Interface 50 also includes:

[0132] - Multiple pins 55 extending parallel to the corresponding axis H; and

[0133] - Multiple ball joints 56, which are integral with corresponding pins 55 and rotate about corresponding axes H and are hinged to the satellite wheel carrier 30 to allow the pins 55 to tilt relative to the satellite wheel carrier 30 about axes F, G.

[0134] More specifically, each pin 55 includes:

[0135] - The cylindrical end portion 64 axially opposite to the corresponding rib 53; and

[0136] - A portion 65 inserted between the corresponding rib 53 and portion 64, which tapers gradually from the corresponding rib 53 to portion 64.

[0137] Each ball joint 56 includes:

[0138] - An element 60, through which a corresponding pin 55 passes, is angularly fixed to the corresponding pin 55 relative to the corresponding axis H, and defines a partially spherical surface 57 on the opposite side of the pin 55; and

[0139] - Element 61, which includes a partially spherical surface 62 connected to the surface 57 of element 60, and a cylindrical surface 63 that is radially external to the surface 57.

[0140] Elements 60 and 61 extend symmetrically with respect to plane P.

[0141] Pin 55 is axially fixed relative to the corresponding ball joint 56 with respect to the corresponding axis H, for example by the corresponding nut.

[0142] Pin 55 represents the portion of interface 50 that can tilt relative to satellite wheel carrier 30 during torque transmission from sun gear 15 to shaft 11.

[0143] The satellite wheel frame 30 has a ring structure relative to axis B, which is symmetrical with respect to plane P.

[0144] More specifically, the satellite wheel frame 30 includes:

[0145] - A pair of headplates 70, 71 located in corresponding planes parallel to each other and orthogonal to axis D; and

[0146] - Multiple crossbars 72 are spaced at equal angles around axis D, and extend orthogonally between plates 70 and 71.

[0147] Plates 70 and 71 are respectively arranged on the side of shaft 11 and on the side opposite to the axial direction of shaft 11.

[0148] In addition, plates 70 and 71 define corresponding polygonal seats 73 and 74 with axis D, which are axially stacked on each other and pass through the sun gear 15 with a radial gap.

[0149] Plates 70 and 71 also define a plurality of corresponding holes 75 and 76 (in the case shown, there are 6 holes for each plate 70 and 71), which are spaced apart in an angular direction and are axially stacked and spaced apart from each other.

[0150] Each pair of holes 75 and 76 is passed through by the corresponding pin 32.

[0151] The crossbar 72 defines the corresponding seat 69 for accommodating the corresponding pin 55 and the corresponding ball joint 56.

[0152] Each seat 69 extends parallel to the relevant axis H. Figure 7 It includes corresponding open ends 77 and 78 that are axially opposite to each other and are defined by plates 70 and 71, respectively.

[0153] From the corresponding end 77 toward the corresponding end 78, each seat 69 includes:

[0154] - Frustum-shaped section 80;

[0155] - Cylindrical section 81; and

[0156] - Frustum conical section 82.

[0157] Parts 80 and 82 of each seat 69 are passed through by the corresponding pin 55 in the presence of radial clearance.

[0158] More specifically, portion 80 of each seat 69 is passed through portion 65 of the corresponding pin 55 in the presence of radial clearance.

[0159] Each seat 69 portion 82 is passed through by the end of the corresponding pin 55 portion 64 in the presence of radial clearance.

[0160] The element 61 of each ball joint 56 is fixed to the portion 81 of the corresponding seat 69.

[0161] Part 80 gradually tapers from end 77 to part 81.

[0162] Part 82 gradually tapers from end 78 toward part 81.

[0163] Each seat 69 also includes, axially from portion 80 toward portion 81:

[0164] - Cylindrical section 83; and

[0165] - A truncated tapered portion 84 is axially inserted between portion 83 and portion 81.

[0166] From portion 82 axially to portion 81, each seat 69 also includes:

[0167] - Cylindrical section 85; and

[0168] - A truncated tapered portion 86 is axially inserted between portion 85 and portion 81.

[0169] Each part 83, 85 has a diameter corresponding to the smaller diameter of the corresponding part 80, 81.

[0170] Each part 84, 86 has a smaller diameter corresponding to the diameter of the corresponding part 80, 81.

[0171] Part 81 has a larger diameter than the smaller diameter of parts 84 and 86.

[0172] Seat 69 is radially external relative to holes 75 and 76.

[0173] Each seat 69 is inserted in the angular direction between two consecutive pairs of holes 75 and 76 in the holes 75 and 76.

[0174] In the case shown, there are six crossbars 72.

[0175] Satellite wheel 19 is inserted between two consecutive seats 69 in the angular direction.

[0176] Preferably, the satellite wheel frame 30 is formed by two axially stacked elements 34 and 35.

[0177] Components 34 and 35 are identical to each other.

[0178] Reference Figure 5 Each element 34 (35) includes:

[0179] - Plate 70 (71);

[0180] - The corresponding portions 80, 83, 84 (82, 85, 86) of crossbar 72; and

[0181] - The corresponding half of the corresponding crossbar 72 portion 81.

[0182] Planetary gear 21 also includes a rolling bearing 90 radially inserted between the sun gear 15 and the interface member 50. Figure 2 ).

[0183] The description of the operation of the vertical takeoff and landing reversing aircraft 1 is limited to a single rotor 5 and the associated transmission 9.

[0184] More specifically, the transmission device 9 transmits motion from the motor 10 to the shaft 11 of the rotor 5.

[0185] Power is supplied to the planetary gears 21 via the sun gear 15, which rotates around axis D, and exits via the satellite wheel carrier 30, which is connected to the aforementioned shaft 11 of the rotor 5.

[0186] Since the satellite wheel 19 also meshes with the fixed crown wheel 17, the rotation of the sun wheel 15 causes the satellite wheel 19 to rotate about its axis I and to revolve about its axis D.

[0187] More precisely, due to the rolling bearing 40, the satellite wheel 19 rotates relative to the corresponding pin 32 about the relevant axis I. In particular, the cylindrical roller 45 allows the satellite wheel 19 to rotate relative to the pin 32 about the relevant axis I.

[0188] Furthermore, satellite wheel 19 describes the revolution motion around axis D integrally with satellite wheel frame 30.

[0189] The rotation of the satellite wheel frame 30 transmits power at an appropriate number of revolutions to the shaft 11 of the rotor 5 via the interface 50.

[0190] Specifically, the satellite wheel carrier 30 and the interface member 50 are rotatably integrated with respect to axes D and B in order to transmit torque from the sun gear 15 to the interface member 50.

[0191] Additionally, the ball joint 56 allows the pin 55 of the interface piece 50 to tilt relative to the satellite wheel carrier 30 around the axes F and G, which are orthogonal to the axes D and B.

[0192] This is because the surface 62 of the element 60 fixed to the interface 50 can rotate on the corresponding surface 63 of the element 61 fixed to the satellite wheel frame 30.

[0193] In other words, the ball joint 56 connects the pin 55 of the interface piece 50 and the satellite wheel carrier 30 in a manner that has torsional rigidity relative to axes B and D and flexibly yields relative to axes F and G.

[0194] Therefore, the power transmitted by the sun gear 15 causes the satellite wheel carrier 30 to deform symmetrically with respect to plane P, and thus... Figure 8 The interface component 50 shown is asymmetrically deformed.

[0195] More specifically, the rolling element 45 of each bearing 40 of each satellite wheel 19 is subjected to ( Figure 2 ):

[0196] - A pair of effective forces XI and X2 tangential to the relevant axis I, transmitted by ring 43 after engagement between sun gear 15 and corresponding satellite gear 19;

[0197] - The reaction force Y, which is tangential to the axis I of the associated ball joint 56, is transmitted by the ring 41 after the planetary gear carrier 30 and the interface member 55 are connected via the ball joint 56.

[0198] These effective forces X1, X2 and reaction forces Y are symmetrical with respect to plane P because the rolling body 45 and elements 60, 61 are arranged symmetrically with respect to plane P.

[0199] Since the planetary gear carrier 30 is symmetrical with respect to plane P, it has stiffness that is symmetrical with respect to plane P.

[0200] Therefore, it is preferable that the effective forces X1, X2 and reaction force Y, which have equal moduli and are symmetrical with respect to the plane P, produce the same elastic deformation and displacement on the rolling body 45 arranged on both sides of the plane P.

[0201] Therefore, axes D and I remain parallel to each other.

[0202] The advantages that can be obtained are obvious from the examination of the vertical takeoff and landing reversing aircraft 1 according to the present invention.

[0203] Specifically, the interface 50 is connected to the satellite wheel carrier 30 and the shaft 11 in a manner that allows angular displacement of the axis H of the pin 55 relative to the axis B of the satellite wheel carrier 30.

[0204] Thus, the torque transmitted from the sun gear 15 to the satellite wheel carrier 30 causes the satellite wheel carrier 30 and the interface member 50 to rotate as a unit about axis B, and the pin 55 to deflect relative to the satellite wheel carrier 30 about axes F and G.

[0205] Therefore, during the actuation of the motor 10, the axes I and D of the rolling body 45 of the bearing 40, the satellite wheel 19 and the sun wheel 15 remain completely parallel to each other.

[0206] Therefore, the curve of the change in contact pressure on the rolling body 45 as a function of the axial coordinate of the same rolling body 45 has a substantially flat curve that decreases at the axial end, and exhibits a value significantly lower than that found in known types of schemes and described in the background section of this specification with reference to the inclination between axis I and axis D.

[0207] This results in a significant increase in the duration and operational performance of planetary gear 21.

[0208] The satellite wheel frame 30 is symmetrical with respect to plane P.

[0209] Furthermore, elements 60 and 61 are arranged symmetrically with respect to plane P.

[0210] Therefore, in the case of torque transmission from sun gear 15 to satellite wheel carrier 30, the rolling body 45 is subjected to effective tangential forces X1 and X2 from sun gear 15 transmitted by ring 43 and a reaction tangential force Y from ball joint 56 transmitted by ring 41, the forces being symmetrical with respect to plane P. Figure 2 ).

[0211] Since the stiffness of the aforementioned satellite wheel frame 30 is symmetrical with respect to plane P, the effective forces X1, X2 and reaction force Y are tangent to the corresponding axis I, thus causing the deformation, force and elastic displacement of the rolling body 45 to be basically the same.

[0212] This helps to keep the axes I and D of the rolling body 45 of the bearing 40, the satellite wheel 19 and the sun wheel 15 completely parallel to each other during the actuation of the motor 10, thereby achieving the above-mentioned advantages.

[0213] The continuous circumferential edges 54 of the interface member 50 increase the stiffness of the interface member 50, limiting its elastic deformation and the bending of the axis H caused by the torque transmission from the motor 10 through the satellite wheel frame 30.

[0214] Spoke 53 helps to minimize the asymmetry of the elastic deformation of the interface 50.

[0215] Finally, it is obvious that modifications and variations can be made to the previously described vertical takeoff and landing reversing aircraft 1 without departing from the scope of protection of this invention.

[0216] Furthermore, the crown gear 17 of the planetary gear 21 can rotate around axis D at a different angular velocity than the sun gear 15.

[0217] Furthermore, mechanical power can enter the planetary gear 21 at the satellite wheel carrier 30 and exit at the sun gear 15 with the correct torque value and revolutions.

[0218] In addition, the transmission device 9 may include two or more planetary gears 21 connected in series or in parallel with each other.

[0219] Furthermore, the transmission device 9 can be at least partially integrated into a turbine of the motor 10.

[0220] Finally, the transmission 9 and planetary gear 21 can be used in helicopters or in aircraft capable of remotely controlled hovering (commonly known as UAVs).

Claims

1. A hovering aircraft (1), comprising: - At least one motor component (10); - At least one rotor (5) is operably connected to the motor component (10); - At least one drive shaft (11) rotatable about a first axis (B) and adapted to drive the rotor (5); and - At least one transmission device (9) is inserted between the motor component (10) and the rotor (5); The transmission device (9) includes a planetary gear (21) formed from the following components: - The sun gear (15) is able to rotate about the second axis (D) with a first angular velocity; - Crown wheel (17), which is fixed in an angular direction relative to the second axis (D), or can rotate around the second axis (D) at a second angular velocity different from the first angular velocity; - At least two satellite wheels (19), each of which meshes with the crown wheel (17) and the sun wheel (15) and is rotatable about a corresponding third axis (I), which is rotatable about a second axis (D); as well as - Satellite wheel frame (30), which is rotatable about the second axis (D) and includes at least two first pins (32), the satellite wheel (19) being rotatable about the corresponding third axis (I) relative to the at least two first pins; The transmission device (9) mentioned above includes: - An interface piece (50) inserted between the satellite wheel frame (30) and the drive shaft (11), the interface piece (50) being integral with the satellite wheel frame (30) in an angular direction around the second axis (D) and integral with the drive shaft (11) in an angular direction around the first axis (B); The interface (50) is connected to the satellite wheel frame (30) and the drive shaft (11) to allow angular displacement between a portion of the interface (50) and the second axis (D); The interface element (50) is hinged to the satellite wheel frame (30) such that the portion can tilt relative to the satellite wheel frame (30) at least about a fourth axis orthogonal to the first axis (B) and the second axis (D); The portion includes a plurality of second pins (55) parallel to the respective fifth axis (H); and it includes a plurality of ball joints (56) integrally formed with the respective second pins (55) in an angular direction around the first axis (B) and hinged to the satellite wheel frame (30) to allow the interface member (50) to tilt relative to the satellite wheel frame (30) around the at least one fifth axis; The interface component (50) includes an annular body, which is rotatably connected to the drive shaft (11), and the second pin (55) protrudes axially from the annular body in a cantilever manner. The annular body is characterized by comprising a plurality of radially extended spokes (53) spaced at equal angles. Each second pin (55) cantilevered axially from the associated spoke (53); The annular body includes: - A first end edge (52) that is circumferentially continuous and radially inward; and - A circumferentially continuous second end edge (54), which is radially outward and axially superimposed on the second pin (55); The spokes (53) extend radially between the first end edge (52) and the second end edge (54) in the circumferential direction.

2. The aircraft of claim 1, wherein, The ball joint (56) includes: - A first element (60) defining a first spherical surface (62) and fixed to a corresponding second pin (55); and - A second element (61) defines a second spherical surface (63) that contacts the associated first spherical surface (62) and is fixed to the satellite wheel frame (30).

3. The aircraft according to claim 1, characterized in that, The satellite wheel frame (30) is limited to: - A plurality of first seats, the plurality of first seats being angularly spaced apart and accommodating corresponding first pins (32); and - A plurality of second seats (69) are spaced apart at equal angles and accommodate corresponding second pins (55).

4. The aircraft according to claim 3, characterized in that, The second seat (69) is radially outward relative to the first seat.

5. The aircraft according to claim 3, characterized in that, Each of the second seats (69) is circumferentially inserted between two circumferentially consecutive first seats in the first seat.

6. The aircraft according to claim 3, characterized in that, The satellite wheel frame (30) includes a pair of half-elements that are axially stacked on each other parallel to the second axis (D), defining corresponding axial ends of the first seat and defining a plurality of second seats (69) that receive the corresponding ball joint (56).

7. The aircraft according to claim 2, characterized in that, It includes a plurality of rolling bearings (40), each of which is inserted between a corresponding first pin (32) and a corresponding satellite wheel (19); Each of the rolling bearings (40) includes: - The first ring (41) is integral with the first pin (32) in the angular direction and defines the first raceway (42). - A second ring (43), which is integral with the corresponding satellite wheel (19) in the angular direction and defines a second raceway (44); and - A plurality of rolling bodies (45) formed as cylindrical rollers are radially inserted between the first ring (41) and the second ring (43) and roll on the first raceway (42) and the second raceway (44) in use.

8. The aircraft according to claim 7, characterized in that, The satellite wheel (19) has a symmetry plane (P) orthogonal to the corresponding third axis (I); The rolling body (45) of each of the rolling bearings (40) is arranged symmetrically with respect to the plane of symmetry (P); The satellite wheel frame (30) is symmetrical with respect to the plane of symmetry (P).

9. The aircraft according to claim 8, characterized in that, The first element (60) and the second element (61) extend symmetrically with respect to the plane of symmetry (P).

10. The aircraft according to claim 1, characterized in that, The aircraft is a vertical takeoff and landing reversible aircraft or a helicopter. The vertical takeoff and landing reversing aircraft includes a pair of motor components (10), a pair of rotors (5), and a pair of transmission devices (9), each of the transmission devices being inserted between the corresponding motor component (10) and the corresponding rotor (5).

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