Transmission assembly for aircraft

Abstract

A method for operating an aircraft (1; 1 '; 1 ''; 1 '''; 1 ''''; 1 ''''; 1 '''' ''; 1 '''' ''; 1 '''' ''') for driving a transmission assembly (3; 3 '; 3 ''; 3 '''; 3 ''''; 3 '''' '; 3 '''' ''; 3 '''' ''; 3 '''' ''') for transmitting a movement, comprising at least one element to be lubricated (18; 40); 1800, 1800; 1801, 1801; 1400, 1400; 1401), a tank (50; 500 '', 500'' ', 500 '''', 500 '''', 500 '''', 1500, 2500 and passive retention means (60, 60', 501 '', 503'' ', 504 ''', 503'' '', 506'' '', 600'' '', 1600, 2600) adapted to prevent lubrication fluid from flowing out of the tank (50, 500'', 500 ''', 500'' '', 500'' '', 1500, 2500) when the temperature of the component (18, 40, 1800, 1801, 1400, 1401) to be lubricated is below a threshold value in use, and to prevent lubrication fluid from flowing out of the tank (50, 500'', 500 '''', 500 '''', 500 '''', 1500, 2500) when the component (18, 40, 1800, 1801, 1801) to be lubricated in use.

Description

Cross-references to related applications

[0001] This patent application claims priority to European Patent Applications No. 23180561.5 and No. 24183061.1, both filed on 21 June 2023, the entire disclosure of which is incorporated herein by reference. Technical Field

[0002] This invention relates to a transmission assembly for aircraft. Background Technology

[0003] The present invention relates in particular to a transmission assembly for hovering aircraft (e.g., helicopters or vertical takeoff and landing aircraft).

[0004] A helicopter is generally known to consist of a fuselage, a main rotor located on top of the fuselage and rotating around its own axis, and an auxiliary rotor located at the tail end of the fuselage.

[0005] The aircraft also includes, in a known manner, one or more motor components, such as turbines, and a transmission assembly located between the turbine and the main rotor and adapted to transmit motion from the turbine to the main rotor. The aircraft may also include additional transmission assemblies adapted to transmit motion from the turbine to a plurality of accessory devices adapted to, for example, supply energy required for operating onboard equipment.

[0006] Ensuring proper lubrication of the transmission components is essential during aircraft operation, as insufficient lubrication can pose a risk to the entire aircraft. For this purpose, the aircraft includes a circuit for the overall lubrication of the transmission components.

[0007] However, some critical components of the transmission system tend to reach particularly high temperatures during operation, and it is known that the lubrication circuits of the aircraft's transmission system are not always adequate to ensure lubrication of these critical components, thus limiting the locally reached temperatures.

[0008] Therefore, it is necessary to ensure the lubrication of critical components of the transmission assembly in this field. Summary of the Invention

[0009] The object of the present invention is to provide a transmission assembly for an aircraft that meets the above-mentioned needs in a simple and inexpensive manner.

[0010] US-A1-2021 / 116016 discloses a lubrication system including a main lubrication system for a gearbox of an aircraft. The main lubrication system includes a first lubricant tank and an emergency lubrication system for the gearbox. The emergency lubrication system includes: a second lubricant tank coupled to the gearbox of the aircraft; a passive thermostat coupled between the second lubricant tank and the gearbox via a lubricant line; and a conductor coupled between the passive thermostat and the gearbox and configured to conduct heat from the gearbox to the passive thermostat, wherein the passive thermostat is configured to open in response to the conductor being exposed to a temperature exceeding a threshold temperature.

[0011] US-B2-11415174 discloses an embodiment of a solid lubricant assembly for providing over-temperature protection for bearings and gears in a rotorcraft system. The solid lubricant enters a fluid state above a specific temperature and is positioned such that the fluid lubricant is applied to the bearing or gear.

[0012] The above objective is achieved by the present invention, which relates to a transmission assembly as defined in claims 1, 19, 26, 27, 28 and 29. Attached Figure Description

[0013] To better understand the present invention, nine preferred embodiments are described below by way of non-limiting examples and with reference to the accompanying drawings, wherein:

[0014] Figure 1 This is a perspective view of a helicopter including the transmission assembly according to the first embodiment of the present invention;

[0015] Figure 2 yes Figure 1 A three-dimensional view of the transmission components;

[0016] Figure 3 It is along Figure 2 A cross-section of plane III-III and a magnified view;

[0017] Figure 4 and Figure 5 yes Figure 3 The detailed view of the cross section shown illustrates the transmission components in their respective different operating positions;

[0018] Figure 6 yes Figures 1 to 5 A further enlarged exploded view of the components of the transmission assembly;

[0019] Figure 7 This is a perspective view of a portion of a transmission assembly according to a second embodiment of the present invention;

[0020] Figure 8 and Figure 9It is a three-dimensional sectional view, showing the corresponding different operating positions at an enlarged scale. Figure 7 Transmission components;

[0021] Figure 10 and Figure 11 This is a cross-sectional view of a portion of the transmission assembly according to a third embodiment of the present invention at corresponding different operating positions;

[0022] Figure 12 and Figure 13 This is a cross-sectional view of a portion of the transmission assembly according to a fourth embodiment of the present invention at corresponding different operating positions;

[0023] Figure 14 and Figure 15 This is a cross-sectional view of a portion of the transmission assembly according to a fifth embodiment of the present invention at corresponding different operating positions;

[0024] Figure 16 and Figure 17 This is a cross-sectional view of a portion of the transmission assembly according to a sixth embodiment of the present invention at corresponding different operating positions;

[0025] Figure 18 and 19 This is a cross-sectional view of a portion of the transmission assembly according to the seventh embodiment of the present invention at corresponding different operating positions;

[0026] Figure 20 and Figure 21 They are respectively in Figure 18 and Figure 19 A detailed view of the transmission assembly according to the seventh embodiment, showing the operating position;

[0027] Figure 22 and 23 This is a cross-sectional view of a portion of the transmission assembly according to the eighth embodiment of the present invention at corresponding different operating positions; and

[0028] Figure 24 and 25 This is a cross-sectional view of a portion of the transmission assembly according to the ninth embodiment of the present invention at corresponding different operating positions. Detailed Implementation

[0029] Reference Figure 1 The number 1 indicates an aircraft capable of hovering. In the non-limiting embodiment shown, the aircraft is a helicopter.

[0030] In the following sections of this specification, the terms "forward," "backward," "up," and "down" are used with reference to the normal flight direction and operational position of the aircraft 1 shown in the accompanying drawings. A reference frame integrated with the aircraft 1 may also be defined, which includes ( Figure 1 ):

[0031] - Longitudinal axis X;

[0032] - The transverse axis Y, orthogonal to axis X; and

[0033] - An axis Z orthogonal to axes X and Y, which points vertically toward the ground during normal operating conditions of aircraft 1.

[0034] Aircraft 1 includes:

[0035] - Fuselage 1a;

[0036] - One or more turbines 2;

[0037] - Main rotor 4, located on top of fuselage 2 and capable of rotating about axis A; and

[0038] - Auxiliary rotor 5, located at the tail end of fuselage 2 and capable of rotating about its own axis B, which is transverse to axis A.

[0039] More specifically, rotor 4 basically includes:

[0040] - A drive shaft 11 capable of rotating around axis A;

[0041] - Hub 12, which is driven to rotate by drive shaft 11; and

[0042] - Multiple blades 13 hinged to hub 12.

[0043] The helicopter 1 also includes a transmission assembly 3, which transmits motion from the turbine 2 to the main rotor 4.

[0044] Transmission assembly 3 includes a terminal stage 20 formed essentially by a planetary gear train 21, which transmits power to drive shaft 11 with the correct torque and angular velocity values. Figure 2 ).

[0045] In the case shown, planetary gear train 21 is a reduction gear.

[0046] Special reference Figure 3 The planetary gear system 21 basically includes:

[0047] - Sun gear 15, which includes a plurality of teeth 16, is rotatable about axis A and is operably connected to the inlet shaft 22 of terminal stage 20;

[0048] - Crown gear 17, which is fixed at an angle relative to axis A; and

[0049] - Multiple gears that perform the functions of the corresponding planetary gears 18, which are rotatable about the corresponding axis I parallel to axis A and mesh with the sun gear 15 and the crown gear 17.

[0050] The planetary gear train 21 also includes a planetary gear carrier 30, which is rotatable about axis A, directly connected to drive shaft 11 and connected to planetary gears 18.

[0051] Crown gear 17 has a larger diameter than sun gear 15 and surrounds planetary gear carrier 30. Furthermore, crown gear 17 is supported by a fixed structure shown only partially in the accompanying drawings.

[0052] Specifically, each planetary gear 18 rotates relative to the planetary gear carrier 30 about its own axis I and performs a rotational motion about axis A integrally with the planetary gear carrier 30.

[0053] Mechanical power enters the planetary gear train 21 at the sun gear 15 and exits at the planetary gear carrier 30 in the direction of the drive shaft 11 with the correct torque value and revolutions.

[0054] Planetary gear carrier 30 further includes ( Figure 2 and Figure 3 ):

[0055] - The main body 31 is arranged coaxially with axis A;

[0056] - Multiple pins 32, which extend along a corresponding axis I, and a corresponding planetary gear 18 is rotatably mounted on the pin about the corresponding axis I;

[0057] - A plurality of arms 33, each extending radially cantileveredly from the body 31 and each having a corresponding pin 32 connected to the body 31; and

[0058] - Multiple rolling bearings 40, each rolling bearing being radially positioned between a corresponding pin 32 and an associated planetary gear 18.

[0059] In detail, the main body 31 is opposite to the arm 33 and the inlet shaft 22.

[0060] Furthermore, preferably, all arms 33 are identical to each other.

[0061] Each bearing 40 is adapted to support a corresponding planetary gear 18 on a corresponding pin 32 in a rotational manner about the corresponding axis I.

[0062] In the following sections of this specification, reference will be made to a single bearing 40 and its associated pin 32, since all bearings 40 and pins 32 are identical to each other.

[0063] Bearing 40 includes ( Figure 3 ):

[0064] - Ring 41, which is fixed at an angle relative to pin 32 and defines seat ring 42;

[0065] - Ring 43, integrally defined by planetary gear 18, is arranged radially outward relative to axis I compared to ring 41, and defines a seat ring 44 facing seat ring 42; and

[0066] - Multiple rolling elements 45, which roll on seat rings 42, 44.

[0067] In detail, Ring 41 includes ( Figure 4 and Figure 5 ):

[0068] - The radial inner surface 41a relative to axis I contacts pin 32;

[0069] - The radial outer surface 41b relative to axis I includes a seat ring 42; and

[0070] - Two annular elements 41c and 41d extend radially cantilevered from the radial outer surface 41b toward the ring 43.

[0071] Two annular elements 41c and 41d are spaced apart from each other parallel to axis I, and define corresponding shoulders for the body 45 parallel to axis I. More specifically, annular element 41c is arranged on the side of arm 33, and annular element 41d is opposite to annular element 41c relative to the body 45, parallel to axis I.

[0072] Pin 32 includes a cylindrical body 34 extending parallel to axis I from the corresponding arm 33. The cylindrical body 34 further includes, relative to axis I:

[0073] - Radial inner surface 35;

[0074] - Radial outer surface 36; and

[0075] - A compartment 37 defined by a radial inner surface 35.

[0076] In detail, compartment 37 includes a segment 37a arranged on the side of arm 33 and a compartment 37b opposite to arm 33 relative to segment 37a. More specifically, the extension of segment 37a orthogonal to axis I is smaller than the extension of segment 37b orthogonal to axis I. Segments 37a and 37b are cylindrical and coaxial with axis I.

[0077] Transmission assembly 3 also includes a main lubrication circuit 47 (shown only partially), in which lubricating fluid flows to lubricate the planetary gear train 21, particularly the planetary gears 18 and bearings 40. Figure 3 ).

[0078] In detail, in the illustrated embodiment, pin 32 includes two holes 48, 49 that extend radially from the inner radial surface 35 to the outer radial surface 36 relative to axis I. More specifically, holes 48, 49 are spaced apart from each other parallel to axis I and are arranged at section 37b. Holes 48 and 49 form part of the main lubrication circuit 47 and are adapted to allow the passage of lubricating fluid flowing therein.

[0079] Transmission assembly 3 also includes ( Figure 3 ):

[0080] - A rotating and fixed housing 23 that accommodates the planetary gear train 21; and

[0081] - A rolling bearing 24 is radially positioned between the planetary gear carrier 30 and the housing 23 and is adapted to support the rotation of the planetary gear carrier 30 relative to the housing 23.

[0082] Transmission assembly 3 includes:

[0083] - Tank 50 for lubricating fluid; and

[0084] - Passive retaining device 60, which is adapted to prevent lubricating fluid from flowing out of the tank 50 when the temperature of the bearing 40 and / or planetary gear 18 is below a threshold, and to allow lubricating fluid to flow out of the tank 50 when the temperature of the bearing 40 and / or planetary gear 18 is above or equal to the threshold.

[0085] In detail, a threshold can be a range of values.

[0086] The lubricating fluid flowing out of tank 50 is suitable for lubricating bearing 40 and / or planetary gear 18.

[0087] In the following sections of this specification, the temperature of a component (e.g., bearing 40 or planetary gear 18) refers to the local temperature at any point on the component (e.g., a point on the component near the retaining device 60), the average temperature of the component, or the temperature around the component (e.g., the temperature of the air around the component).

[0088] Furthermore, preferably, the lubricating fluid flowing in the main lubrication circuit 47 is the same as the lubricating fluid contained in the tank 50. Additionally, the tank 50 is preferably filled with lubricating fluid before installation. In other words, the tank 50 is a container for the lubricating fluid.

[0089] The passive nature of the retaining device 60 means that the transition from its structure preventing the lubricating fluid from flowing out to its structure allowing the lubricating fluid to flow out occurs without the external supply of electrical, pneumatic, or hydraulic power.

[0090] exist Figures 1 to 6In the embodiment shown, the retaining device 60 includes a valve 60, which can be arranged as follows:

[0091] - A closing mechanism that prevents lubricating fluid from flowing out of tank 50. Figure 4 );or

[0092] - An openable structure that allows lubricating fluid to flow out of tank 50 ( Figure 5 ).

[0093] The valve 60 is adapted to automatically move from a closed configuration to an open configuration when the temperature of the bearing 40 and / or the associated planetary gear 18 exceeds a threshold. Preferably, the valve 60 is adapted to move from the closed configuration to the open configuration in an irreversible manner. In other words, once arranged in the open configuration, the valve 60 cannot automatically return to the closed configuration.

[0094] In detail, the tank 50 can rotate around axis A as an integral part of the planetary gear carrier 30.

[0095] like Figure 3 As shown, the canister 50 is radially inward of the planetary gear carrier 30 relative to axis A. Specifically, the canister 50 is arranged coaxially with axis A.

[0096] The tank 50 further includes a main body 51 and a plurality of attachments 52 extending radially cantileveredly from the main body 51. More specifically, the attachments 52 extend radially toward the crown gear 17.

[0097] In detail, the body 51 includes a compartment 510 adapted to contain at least a portion of the lubricating fluid of the tank 50.

[0098] The main body 51 also includes a base surface 51a facing the sun gear 15 and a top surface 51b parallel to the axis A and opposite to the base surface 51a.

[0099] The tank 50 includes an attachment 52 at each arm 33. Specifically, each attachment 52 is aligned with the corresponding arm 33 in the circumferential direction relative to axis A. Furthermore, each attachment 52 is positioned parallel to the corresponding axis I between the corresponding arm 33 and the corresponding bearing 40. In other words, each attachment 52 extends directly below the corresponding arm 33 parallel to the corresponding axis I.

[0100] Furthermore, preferably, the extension of each arm 33 in the circumferential direction relative to axis A is greater than or equal to the extension of the associated attachment 52 in the same circumferential direction.

[0101] In detail, attachment 52 extends from the body 51 in a corresponding direction J transverse to axis A, said direction J being the generatrix of an imaginary conical surface having a vertical axis coinciding with axis A and a vertex belonging to axis A, and is arranged relative to the sun gear 15 on the side opposite to the inlet shaft 22. More specifically, attachment 52 extends from the base surface 51a ( Figure 3 , Figure 4 and Figure 5 ).

[0102] Below, we will refer to only one Annex 52, since all Annexes 52 are identical to each other.

[0103] Annex 52 includes a cavity 53 adapted to at least partially accommodate the valve 60 and guide lubricating fluid. Figure 4 and Figure 5 ).

[0104] Cavity 53 further includes openings 54 and 55, opening 54 fluidly connecting compartment 510 to cavity 53, and opening 55 adapted to allow lubricating fluid to flow out of cavity 53 and thus out of tank 50. Specifically, opening 55 faces directly towards bearing 40. More specifically, opening 55 faces directly towards annular element 41c. Figure 4 and Figure 5 ).

[0105] Annex 52 also includes a radially outer surface 56 relative to axis A and another opening 57 disposed at the radially outer surface 56.

[0106] like Figure 4 and Figure 5 As shown, ring 41 includes a protrusion 46 extending parallel to axis I on the side of ring 41 facing the top surface 51b. In detail, protrusion 46 is radially located between the radial inner surface 41a and the radial outer surface 41b.

[0107] Preferably, the radial outer surface 56 abuts against the protrusion 46.

[0108] Furthermore, preferably, the protrusion 46 extends over the entire circumferential extension of the ring 41 relative to the axis I.

[0109] In the illustrated embodiment, cavity 53 includes ( Figure 4 and Figure 5 ):

[0110] - Section 53a, which is arranged on the side of the base surface 51a, is cylindrical and oriented parallel to direction J;

[0111] - Section 53b, which is arranged on the radial outer surface 56, is also cylindrical and oriented parallel to direction J; and

[0112] - A segment 53c extending between opening 54 and segment 53a, having a cylindrical shape and oriented laterally to direction J.

[0113] In detail, the radial extension of segment 53b in the plane perpendicular to direction J is greater than the radial extension of segment 53a in the plane perpendicular to the same direction J.

[0114] In addition, opening 55 is located at section 53b ( Figure 4 and Figure 5 ).

[0115] valve 60 includes ( Figure 6 ):

[0116] - Reciprocating component 61, which is capable of sliding within cavity 53; and

[0117] - Fusible element 63, which is adapted to be solid below a threshold temperature and to melt at a temperature equal to or above the threshold temperature.

[0118] The reciprocating member 61 slides between a first position and a second position. In the first position, the reciprocating member 61 determines that the opening 55 is blocked; in the second position, the reciprocating member determines that the opening 55 is unblocked. When the valve 60 is in the closed configuration ( Figure 4 When the reciprocating component 61 is in the first position, and when the valve 60 is in the open position ( Figure 5 When ), reciprocating component 61 is in the second position.

[0119] The fusible element 63 is adapted to hold the reciprocating member 61 in a first position when the fusible element 63 is in a solid state, and is adapted to determine and / or allow the reciprocating member 61 to slide toward a second position when the fusible element 63 is at least partially melted.

[0120] The valve 60 also includes a striker element 62 integrated with accessory 52.

[0121] More specifically, when the valve 60 is in the closed configuration, the fusible element 63 is adapted to keep the reciprocating element 61 and the firing pin element 62 at a certain distance from each other. Figure 4 When the valve 60 is in the open position, the reciprocating member 61 abuts against the striking pin element 62. Figure 5 ).

[0122] In addition, the firing pin element 62 is arranged at section 53b and positioned against the protrusion 46.

[0123] The valve 60 also includes an elastic device 64 adapted to preload the reciprocating member 61 toward the second position. In detail, the elastic device 64 includes a helical spring that engages with the reciprocating member 61 on the side opposite to the striker element 62.

[0124] The valve 60 also includes a sealing element 65, which is slidable integrally with the reciprocating member 61 relative to the cavity 53. Specifically, the sealing element 65 is assembled around the reciprocating member 61. Furthermore, the sealing element 65 is located between the reciprocating member 61 and the inner wall of the cavity 53.

[0125] When the valve 60 is in the closed configuration, the sealing element 65 blocks the opening 55 and prevents fluid communication between the opening 54 and the opening 55. Figure 4 Conversely, when the valve 60 is in the open configuration, the sealing element 65 does not obstruct the opening 55 and allows fluid communication between the opening 54 and the opening 55. Figure 5 Therefore, the reciprocating component 61 only indirectly contributes to the blocking and non-blocking of the opening 55.

[0126] like Figure 6 As shown, the reciprocating member 61 includes a cylindrical portion 61a disposed on the side of the firing pin element 62 and a portion 61b that is also cylindrical and parallel to the direction J and opposite to portion 61a. In detail, the radial extension of portion 61a is greater than the radial extension of portion 61b.

[0127] The reciprocating component 61 also includes a seat 61c, which is parallel to direction J, located between portions 61a and 61b, and is adapted to accommodate the sealing element 65.

[0128] Reciprocating component 61 also includes:

[0129] - Compartment 61d, which is arranged on the side opposite to portion 61b at portion 61a; and

[0130] - An opening 61e at part 61a passes radially through relative to direction J and communicates directly with compartment 61d.

[0131] The reciprocating component 61 also includes a flat surface 61f, which is oriented perpendicular to direction J and disposed at the end of the reciprocating component 61 opposite to portion 61b.

[0132] In detail, compartment 61d has a cylindrical shape and extends from surface 61f toward portion 61b, and portion 61a extends along direction J. Additionally, opening 61e is parallel to direction J and spaced apart from surface 61f.

[0133] Preferably, the reciprocating member 61 includes a plurality of seats 61g adapted to accommodate corresponding elastic bands. The seats 61g are arranged at portion 61a.

[0134] The solid-state fusible element 63 is a cylinder, comprising:

[0135] - The two ends 63a and 63b that are opposite to each other in the direction J;

[0136] - A protrusion 63c, which extends radially in direction J and is adapted to engage the opening 61e in order to prevent relative sliding between the solid fusible element 63 and the body 62 parallel to direction J.

[0137] In detail, the solid fusible element 6 is partially housed in the compartment 61d on the end 63a side. Figure 4 ).

[0138] The fusible element 63 is made of a material suitable for melting at or near a temperature threshold (i.e., a value equal to or higher than the temperature threshold). For example, the fusible element 63 is made of tin or lead or an alloy thereof.

[0139] The firing pin element 62 has a cylindrical or substantially cylindrical body, comprising:

[0140] - A flat adjacent surface 62a facing the reciprocating component 61;

[0141] - End surface 62b, positioned as adjacent protrusion 46; and

[0142] - Adjacent surface 62c, which is parallel to direction J between adjacent surface 62a and end surface 62b.

[0143] In detail, when the reciprocating member 61 is in the first position, the end 63b contacts the adjacent surface 62c; when the reciprocating member 61 is in the second position, the surface 61f contacts the adjacent surface 62a.

[0144] The firing pin element 62 also includes a through opening 62d that passes parallel to direction J and is adapted to allow material of the fusible element 63 in a molten state to pass toward the opening 57.

[0145] like Figure 4 and Figure 5 As shown, the reciprocating member 61 slides between sections 53a and 53b. Specifically, the radial extension of portion 61a is greater than the radial extension of section 53a, and portion 61a is completely accommodated at section 53b. Additionally, the elastic device 64 is completely accommodated at section 53a.

[0146] The operation of the transmission assembly 3 is described below with reference to a single planetary gear 18 and its associated valve 60, and the operation is the same for all planetary gears 18 and associated valves 60. Furthermore, the operation is described starting with the condition that the valve 60 is in the closed configuration and the temperature of the bearing 40 and / or the planetary gear 18 is below a threshold value.

[0147] In operation, the planetary gear train 21 transmits power from the inlet shaft 22 to the drive shaft 11 with the correct torque and angular velocity values. During motion transmission, the components of the transmission assembly 3 are periodically lubricated by the main lubrication circuit 47.

[0148] In detail, the canister 50 rotates integrally with the planetary gear carrier 30, preventing lubricating fluid from flowing out of the canister 50. More specifically, inside the valve 60, the fusible element 63 holds the reciprocating member 61 at a distance from the firing pin element 62 and constrains the reciprocating member 61 in a first position. Therefore, the sealing element 65 blocks the opening 55.

[0149] When the temperature of bearing 40 and / or planetary gear 18 reaches or exceeds a threshold, fusible element 63 melts. The molten material of fusible element 63 flows through openings 62d and 57 and accumulates in the space between protrusion 46, attachment 52 and annular element 41c.

[0150] After the fusible element melts, the elastic device 64 pushes the reciprocating member 61 to the second position until the surface 61f abuts against the adjacent surface 62a.

[0151] During the sliding of the reciprocating component 61, the opening 55 is not obstructed, thus allowing lubricating fluid to flow from the opening 54 to the opening 55. Specifically, the lubricating fluid flows sequentially from the compartment 510 through the opening 54, section 53c, section 53a, section 53b, and opening 55 (e.g., ...). Figure 5 As shown by the arrow.

[0152] The lubricating fluid that has flowed out of the opening 55 flows in the gap between the rings 41, 43 and the body 45 and / or on the surface of the planetary gear 18 and / or between the surface between the planetary gear 18 and the bearing 40, thereby providing emergency lubrication for the bearing 40 and / or the satellite 18.

[0153] Reference Figures 7 to 9 The numeral 3' indicates a transmission assembly according to a second embodiment of the present invention. The transmission assembly 3' is similar to the transmission assembly 3, and will be described below only in the aspects where it differs from the transmission assembly 3; where possible, the same or equivalent parts of the transmission assemblies 3 and 3' will be identified by the same reference numerals.

[0154] The transmission assembly 3' differs from the transmission assembly 3 because it includes a valve 60' instead of a valve 60. Below, reference will be made to a single valve 60', since all valves 60' are identical to each other.

[0155] Similar to valve 60, valve 60' is adapted to control the flow of lubricating fluid from tank 50 to lubricate planetary gear 18 and / or bearing 40.

[0156] valve 60' includes ( Figure 8 and Figure 9 ):

[0157] - Body 61', which is integral with the can 50, particularly integrated into or fixed to the arm 33, and includes cavity 61d'; and

[0158] - Fusible element 63', which is adapted to be solid below a temperature threshold and adapted to melt at least partially at the temperature threshold.

[0159] The cavity 61d' includes an opening 610' for fluid connection to the tank 50 and an opening 611' adapted to allow lubricating fluid to flow out of the cavity 61d'.

[0160] A solid fusible element 63' occupies at least a portion of cavity 61d' and is adapted to prevent fluid communication between opening 610' and opening 611'. The fusible element 63' is also adapted to allow fluid communication between opening 610' and opening 611' when it is at least partially melted.

[0161] More specifically, cavity 61d' includes:

[0162] - Section 612', which extends from opening 610' and has a cross-section that gradually decreases in the direction oriented from opening 610' to opening 611'; and

[0163] - Section 613' extends from section 612' to opening 611'.

[0164] Preferably, segment 612' has a conical shape, and segment 613' has a parallelepiped shape.

[0165] Cavity 61d' can be directly fluidly connected to compartment 510, or connected to cavity 53 of accessory 52 of drive assembly 3'.

[0166] The solid fusible element 63' includes a tapered segment 63a' housed in segment 612' and a parallelepiped-shaped segment 63b' housed in segment 613'. Figure 8 ).

[0167] The valve 60' also includes a resilient device 64'. The resilient device 64' includes a resilient rod 64a' fixed to the planetary gear carrier 30.

[0168] The elastic rod 64a' is in the solid state when the fusible element 63' is in the solid state. Figure 8 When operably connected to the fusible element 63', and when the valve 60' is in the open configuration ( Figure 9 When abutting the pin 32. In detail, the elastic rod 64a' is elastically loaded toward its position abutting the pin 32. More specifically, the elastic rod 64a' is partially embedded in the material of the solid fusible element 63', or engages with an opening formed in the solid fusible element 63'.

[0169] The elastic rod 64a' further includes:

[0170] - Section 64b', which extends in partial contact with the main body 31; and

[0171] - Section 64c', which extends radially toward crown gear 17 from section 64b' relative to axis A.

[0172] In detail, the elastic rod 64a' is fixed to the body 31 at section 64b' and is operatively connected to the solid fusible element 63' at section 64c'. More specifically, when the elastic rod 64a' is in the position it presents when the fusible element 63' is solid, section 64b' is curved and has the shape of an arc centered on a point belonging to axis A or substantially centered on a point belonging to axis A.

[0173] Preferably, when the valve 60' is in the open configuration, section 64c' is adapted to guide lubricating fluid from opening 611' toward the surface to be lubricated. More specifically, section 64c' includes a surface facing the body 31, which is oriented parallel to or substantially parallel to axis A and adapted to guide lubricating fluid.

[0174] More specifically, segment 64b' includes a first end 640' and a second end 641' that are opposite each other in the circumferential direction relative to axis A. Segment 64b' is fixed to body 31 at the first end 640', and segment 64c' extends from segment 64b' at the second end 641'.

[0175] like Figure 8 and Figure 9 As shown, segment 64c' has an S-shape in a plane perpendicular to axis A.

[0176] The operation of transmission assembly 3' is similar to that of transmission assembly 3, and will be described below only in the areas where its operation differs from that of transmission assembly 3. Specifically, the operation is described below with reference to a single planetary gear 18 and its associated valve 60', and the operation is the same for all planetary gears 18 and associated valves 60'. Furthermore, the operation is described starting with the condition that valve 60' is in the closed configuration and the temperature of bearing 40 and / or planetary gear 18 is below a threshold value.

[0177] In detail, inside the valve 60', the fusible element 63' occupies the compartment 61d', thereby preventing lubricating fluid from flowing from the opening 610' to the opening 611'.

[0178] When the temperature is equal to or exceeds the threshold, the fusible element 63' melts due to its proximity to the bearing 40 and / or the planetary gear 18, thereby not blocking the openings 610' and 611' and allowing the resilient device 64' to freely contact the pin 32.

[0179] Then, the lubricating fluid exiting from the opening 611' is guided by the section 64c' and flows into the gap between the rings 41, 43 and the body 45 and / or into the gap on the surface of the planetary gear 18 and / or into the gap between the surface between the planetary gear 18 and the bearing 40, thereby providing emergency lubrication for the bearing 40 and / or the planetary gear 18.

[0180] Reference Figure 10 and Figure 11 The numeral 3'' indicates a transmission assembly according to a third embodiment of the present invention. The transmission assembly 3'' is similar to the transmission assembly 3, and will be described below only in the areas where it differs from the transmission assembly 3; where possible, the same or equivalent parts of the transmission assembly 3'' will be indicated by the same reference numerals.

[0181] Transmission assembly 3'' differs from transmission assembly 3 because it includes:

[0182] - A 500'' canister for lubricating fluid (e.g., grease) at one or all of the planetary gears 18; and

[0183] - Passive retaining device 501'', adapted to prevent lubricating fluid from flowing out of tank 500'' when the temperature of bearing 40 and / or planetary gear 18 is below a threshold, and to allow lubricating fluid to flow out when the temperature of bearing 40 and / or planetary gear 18 is above or equal to the threshold.

[0184] Specifically, the holding device 501'' includes a housing 501'', the housing 501'' defining a container 500'' and is adapted to be solid below a temperature threshold and to melt at the threshold.

[0185] More specifically, when the shell 501'' begins to melt, it forms one or more through openings 502'' through which lubricating fluid contained in the can 500'' flows ( Figure 11 ).

[0186] The canister 500'' is fixed to the ring 41 and is therefore able to rotate integrally with the planetary gear carrier 30 about axis A. Furthermore, the canister 500'' is preferably filled with lubricating fluid before installation. In other words, the canister 500'' is a container for lubricating fluid.

[0187] In addition, tank 500'' has a rectangular cross-section in a plane passing through axis I.

[0188] In detail, the can 500'' is arranged parallel to axis I against the annular element 41c, and parallel to axis I relative to the annular element 41c is opposite to the body 45. The can 500'' also radially abuts against the protrusion 46 relative to axis I.

[0189] Preferably, tank 500'' is an annular body arranged coaxially with axis I.

[0190] The operation of the transmission assembly 3'' is described below starting with the case where the temperature of bearing 40 and / or planetary gear 18 is below a threshold. In this case, housing 501'' is completely solid and prevents lubricating fluid from flowing out of tank 500''.

[0191] When the temperature of bearing 40 and / or planetary gear 18 is equal to or higher than a threshold, housing 501'' melts, thereby forming opening 502'' and allowing lubricating fluid contained in can 500'' to flow out.

[0192] The lubricating fluid that has flowed out of the tank 500' lubricates the contact surfaces between the body 45 and the rings 41, 43 and / or the planetary gear 18.

[0193] Reference Figure 12 and Figure 13 The diagram illustrates a transmission assembly 3''' according to a fourth embodiment of the present invention. The transmission assembly 3''' is similar to the transmission assembly 3'', and will be described below only in the areas where it differs from the transmission assembly 3''; where possible, identical or equivalent parts of the transmission assemblies 3'' and 3''' will be indicated by the same reference numerals.

[0194] The transmission assembly 3''' is different from the transmission assembly 3'' because the tank 500''' includes a housing 501''', which in turn includes an opening 502''' and passive holding devices 503''' and 504'''.

[0195] The retaining devices 503''' and 504''' include:

[0196] - Elastic element 503''', which is arranged in a flat configuration below a temperature threshold and preloaded toward a bending configuration; and

[0197] - Fusible element 504''', which is adapted to be solid below a temperature threshold and adapted to at least partially melt at the threshold.

[0198] The fusible element 504''' is adapted to hold the elastic element 503''' in a flat configuration when the fusible element 504''' is in a solid state, and is adapted to determine the displacement of the elastic element 503''' to the curved configuration when the fusible element 504''' melts.

[0199] The elastic element 503''' in the flat structure, together with the fusible element 504''', blocks the opening 502'''. Figure 12 ).

[0200] In detail, the elastic element 503''' in the flat structure is perpendicular or substantially perpendicular to axis I ( Figure 12 ).

[0201] The elastic element 503''' in the bent configuration at least partially releases the opening 502''', thereby allowing lubricating fluid to flow out of the reservoir 500'''. Specifically, the elastic element 503''' in the bent configuration has a concave surface facing the body 45 ( Figure 13 ).

[0202] Preferably, the housing 501''' is made of metal.

[0203] Considering the cross-section of the transmission assembly 3''' in the plane passing through axis I, housing 501''' includes:

[0204] - The radial outer surface 501a''' relative to axis I;

[0205] - Radial inner surface 501b''';

[0206] - A top surface 501c''', which extends radially relative to axis I between the radially outer surface 501a''' and the radially inner surface 501b''', and is arranged on a side parallel to axis I opposite to the body 45; and

[0207] - The base surface 501d''', which is parallel to axis I and opposite to the top surface 501c''' and in contact with the annular element 41c.

[0208] The radial outer surface 501a''' includes a tooth 505''' at its end parallel to axis I and opposite to the top surface 501c'''. The tooth 505''' extends radially toward the radial inner surface 501b'''. Figure 12 and Figure 13 ).

[0209] The base surface 501d''' extends only a portion of the radial extension of the can 500''' from the radial inner surface 501b''' toward the radial outer surface 501a'''.

[0210] More specifically, the opening 502''' is defined by the radial and axial space between the radial outer surface 501a''' and the base surface 501d'''.

[0211] Furthermore, opening 502''' faces the body 45. In particular, opening 502''' faces the annular element 41c.

[0212] The elastic element 503''' extends radially from the radially inner surface 501b'' toward the radially outer surface 501a'' relative to the axis I. Preferably, the elastic element 503''' is spaced apart from the radially outer surface 501a'' both radially relative to the axis I and parallel to the axis I.

[0213] In the radial direction relative to axis I and parallel to axis I, a solid fusible element 504''' is located between the radial outer surface 501a'' and the elastic element 503'''.

[0214] Considering the cross-section of the fusible element 504''' in the plane passing through axis I, the solid fusible element 504''' includes:

[0215] - The first straight segment oriented parallel to axis I;

[0216] - A second segment extending radially from the first segment toward the radially outer surface 501a'''; and

[0217] - The third segment extends radially from the first segment toward the radial inner surface 501b'''.

[0218] The second and third sections are arranged at corresponding opposite ends of the first section, parallel to axis I. In other words, the solid fusible element 504''' has an S-shape in the plane passing through axis I.

[0219] In detail, the solid fusible element 504''' contacts the tooth 505''' in the second section and contacts the elastic element 503''' in the third section. More specifically, the second section is opposite to the tooth 505''' and the third section is opposite to the elastic element 503''' and the second section.

[0220] The operation of transmission assembly 3''' is similar to that of transmission assembly 3'', and therefore will be described starting from the range where its operation differs from that of transmission assembly 3'' and from the case where the temperature of bearing 40 and / or planetary gear 18 is below a threshold and thus prevents lubricating fluid from flowing out of tank 500'''.

[0221] Specifically, when the temperature of the bearing 40 and / or the planetary gear 18 is equal to or exceeds a threshold, the fusible element 504''' melts, thereby allowing the elastic element 503''' to be arranged in a bending configuration.

[0222] At this point, the elastic element 503''' partially exposes the opening 502''', thereby allowing lubricating fluid to flow out from the tank 500'''.

[0223] The lubricating fluid from tank 500''' lubricates the contact surfaces between body 45 and rings 41, 43 and / or planetary gear 18.

[0224] Reference Figure 14 and Figure 15 The numeral 3'''' indicates a transmission assembly according to a fifth embodiment of the present invention. The transmission assembly 3'''' is similar to the transmission assembly 3'', and will be described below only in the aspects where it differs from the transmission assembly 3''; where possible, the same or equivalent parts of the transmission assembly 3''; 3''''' will be indicated by the same reference numerals.

[0225] The transmission assembly 3'''' is different from the transmission assembly 3'' because the tank 500'''' includes a housing 501'''', which in turn includes an opening 502'''' and a passive holding device 503''''.

[0226] The retaining device 503'''' includes an element 503'''' made of shape memory material, which is arranged in a flat configuration below a temperature threshold and adapted to regain a bent configuration at the threshold.

[0227] The element 503, with its flat construction, blocks the opening 502. Preferably, the element 503, with its flat construction, is perpendicular or substantially perpendicular to axis I. Figure 14 More specifically, the opening 502'''' is defined by the radial and / or axial space between the radial outer surface 501a'''' and the base surface 501d''''.

[0228] The element 503'''' in the curved configuration at least partially releases the opening 502'''', thereby allowing lubricating fluid to flow out. Specifically, the element 503'''' in the curved configuration has a concave surface facing the body 45 ( Figure 15 ).

[0229] The element 503'''', which is in a flat construction, extends radially from the radial inner surface 501'''' toward the radial outer surface 501'''' relative to the axis I, and contacts the radial outer surface 501''''.

[0230] Preferably, the housing 501'''' is made of metal.

[0231] The operation of transmission assembly 3'''' is similar to that of transmission assembly 3'', therefore it will be described starting from the range where its operation differs from that of transmission assembly 3'' and from the case where the temperature of bearing 40 and / or planetary gear 18 is below a threshold and lubricating fluid is prevented from flowing out of tank 500''''.

[0232] When the temperature of bearing 40 and / or planetary gear 18 is equal to or exceeds a threshold, element 503'''' returns to a bent configuration, thereby partially exposing opening 502'''' and allowing lubricating fluid to flow out from can 500''''.

[0233] The lubricating fluid that has flowed out of the tank 500'''' has lubricated the contact surfaces between the body 45 and the rings 41, 43 and / or the planetary gear 18.

[0234] Reference Figure 16 and Figure 17 The numeral 3''''' indicates a transmission assembly according to a sixth embodiment of the present invention. The transmission assembly 3''''' is similar to the transmission assembly 3'', and will be described below only in the areas where it differs from the transmission assembly 3''; where possible, the same or equivalent parts of the transmission assembly 3''; 3'''''' will be indicated by the same reference numerals.

[0235] The transmission assembly 3''''' is different from the transmission assembly 3'' because the tank 500''''' includes the housing 501''''', which in turn includes the opening 502''''' and the passive holding devices 503''''' and 506'''''.

[0236] The retaining devices 503''''' and 506''''' include:

[0237] - Elastic element 503''''', which is arranged in a flat configuration below a temperature threshold and preloaded toward a bending configuration; and

[0238] - Element 506''''', made of shape memory material, is adapted to contact and engage with elastic element 503'''''. Element 506''''' is adapted to be arranged in a compressive configuration below a temperature threshold and to regain an extended configuration at the temperature threshold.

[0239] The elastic element 503, with a flat construction, blocks the opening 502. Preferably, the element 503, with a flat construction, is perpendicular to or substantially perpendicular to axis I. Figure 16 ).

[0240] The element 503, in its curved configuration, at least partially releases the opening 502, thereby allowing lubricating fluid to flow out. Specifically, the element 503, in its curved configuration, has a concave surface facing the body 45. Figure 17 ).

[0241] More specifically, the opening 502''''' is defined by the radial and / or axial space between the radial outer surface 501a''''' and the base surface 501d'''''.

[0242] The elastic element 503 extends radially from the radial inner surface 501b toward the radial outer surface 501a relative to the axis I, and is fixed to the radial outer surface 501a.

[0243] The element 506''''' in the compression configuration is adapted to hold the elastic element 503''''' in the flat configuration. The element 506''''' in the extension configuration is adapted to remove and / or detach the elastic element 503''''' from the housing 501'''' (particularly from the radial outer surface 501a''''') thereby allowing the elastic element 503''''' to be arranged in a bending configuration.

[0244] Preferably, element 506 extends into the internal volume of can 500 and includes a first end and a second end that are parallel to each other on axis I. Specifically, the first end is fixed to the top surface 501c and the second end is fixed to the elastic element 503.

[0245] Additionally, preferably, the element 506'''' in the extended configuration is parallel to or substantially parallel to axis I.

[0246] Preferably, the housing 501''''' is made of metal.

[0247] The operation of transmission assembly 3''''' is similar to that of transmission assembly 3'', and therefore will be described starting from the range where its operation differs from that of transmission assembly 3'' and from the case where the temperature of bearing 40 and / or planetary gear 18 is below a threshold and thus prevents lubricating fluid from flowing out of tank 500'''''.

[0248] Specifically, when the temperature of bearing 40 and / or planetary gear 18 is equal to or exceeds a threshold, element 506 returns to the extended configuration, thereby disengaging elastic element 503 from radial outer surface 501a.

[0249] Therefore, the elastic element 503''''' is arranged in a curved configuration, partially exposing the opening 502''''' and allowing lubricating fluid to flow out from the tank 500'''''.

[0250] The lubricating fluid that has flowed out of the tank 500'''''' has lubricated the contact surfaces between the body 45 and the rings 41, 43 and / or the planetary gear 18.

[0251] Reference Figures 18 to 21The numeral 3'''''' indicates a transmission assembly according to a seventh embodiment of the present invention. The transmission assembly 3'''''' is similar to the transmission assembly 3, and will be described below only in the aspects where it differs from the transmission assembly 3; where possible, the same or equivalent parts of the transmission assembly 3; 3'''''' will be indicated by the same reference numerals.

[0252] Transmission assembly 3'''''' differs from transmission assembly 3 because it includes:

[0253] - A 500-gauge container for lubricating fluid at one or all 18 planetary gears; and

[0254] - Passive retaining device 501'''''', adapted to prevent lubricating fluid from flowing out of tank 500''''' when the temperature of bearing 40 and / or planetary gear 18 is below a threshold, and to allow lubricating fluid to flow out when the temperature of bearing 40 and / or planetary gear 18 is above or equal to the threshold.

[0255] The following will refer only to one can 500 and its associated holding device 501, since all cans 500 and holding devices 501 are identical.

[0256] In detail, the retaining device 501 includes a valve 600, which can be arranged as follows:

[0257] - A closing mechanism that prevents lubricating fluid from flowing out of tank 500. Figure 18 and Figure 20 );or

[0258] - Opening mechanism, in which it allows lubricating fluid to flow out from tank 500'''''' ( Figure 19 and Figure 21 ).

[0259] Valve 600'''''' is adapted to automatically move from a closed configuration to an open configuration when the temperature of bearing 40 and / or associated planetary gear 18 exceeds a threshold. Preferably, valve 600''''' is adapted to move from a closed configuration to an open configuration in an irreversible manner.

[0260] The canister 500 is capable of rotating about axis A integrally with the planetary gear carrier 30. Specifically, the canister 500 is housed in compartment 37 and fixed to pin 32 of the associated planetary gear 18.

[0261] More specifically, tank 500'''''' includes a segment 500a'''''' arranged on the side of arm 33 and a compartment 500b'''''' opposite to arm 33 relative to segment 500a''''''. More specifically, the extension of segment 500a''''''' orthogonal to axis I is smaller than the extension of segment 500b'''''''' orthogonal to axis I. Furthermore, preferably, segments 500a'''''' and segment 500b' ...

[0262] like Figure 18 and Figure 19 As shown, segment 500a'''''' is accommodated at segment 37a, and segment 500b''''''' is accommodated at segment 37b. In detail, segment 500a' ...

[0263] The tank 500 includes a compartment 510 adapted to contain at least a portion of the lubricating fluid of the tank 500 and a cavity 530 adapted to contain a valve 600 fluidly connected to the compartment 510.

[0264] Cavity 530'''''' includes:

[0265] - An opening 540'''''', which fluidly connects compartment 510''''' to cavity 530''''''; and

[0266] - Opening 550'''''', which is adapted to allow lubricating fluid to flow out from cavity 530''''' and thus from tank 500''''''.

[0267] Preferably, the cavity 530'''''' has a cylindrical shape, and its axis is parallel to axis I.

[0268] In detail, opening 550' is fluidly connected to compartment 37. More specifically, when valve 600' is in the closed configuration ( Figure 18 and Figure 20 When and when the valve 600'''''' is in the open configuration ( Figure 19 and Figure 21 When ), opening 550'''''' is connected to compartment 37.

[0269] In the illustrated embodiment, cavity 530'''''' is arranged at section 500b'''''' and is radially spaced from axis I.

[0270] The valve 600 is adapted to automatically move from the closed configuration to the open configuration when the temperature of the bearing 40 and / or the planetary gear 18 exceeds a threshold.

[0271] Valve 600'''''' includes:

[0272] - Reciprocating component 610'''''', which can slide within cavity 530''''''; and

[0273] - Fusible element 630'''''', which is adapted to be solid below a temperature threshold and adapted to at least partially melt at the temperature threshold.

[0274] The reciprocating component 610 can slide between a first position and a second position parallel to axis I. When the valve 600 is in the closed position ( Figure 18 , Figure 20 When the reciprocating component 610 is in the first position, and when the valve 600 is in the open position ( Figure 19 , Figure 21 When ), the reciprocating part 610'''''' is in the second position.

[0275] The reciprocating component 610 in the first position determines that the opening 540 is blocked; the reciprocating component 610 in the second position determines that the opening 540 is not blocked.

[0276] More specifically, when the valve 600 is in the closed configuration, the reciprocating element 610 is adjacent to the fusible element 630 in the solid state.

[0277] The fusible element 630'''''' is adapted to hold the reciprocating element 610''''' in a first position when the fusible element 630'''''' is in a solid state, and is adapted to determine the sliding of the reciprocating element 610''''' toward a second position when the fusible element 630''''''' is at least partially melted.

[0278] The valve 600 also includes a resilient device 640 adapted to resiliently preload the reciprocating member 610 toward the second position. Specifically, the resilient device 640 includes a helical spring that engages with the reciprocating member 610 on the side opposite to the fusible element 630.

[0279] The cavity 530 also includes an opening 560 for the molten material of the fusible element 630 to flow out of the cavity 530.

[0280] In the illustrated embodiment, the main lubrication circuit 47 further includes:

[0281] - Pipe 70, which fluidly connects openings 48 and 49 to each other; and

[0282] - Pipe 71, which extends between pipe 70 and seat ring 42.

[0283] In detail, the conduit 70 is defined by a gap between the radial inner surface 41a and the radial outer surface 36. The conduit 71 preferably extends from the radial inner surface 41a to the radial outer surface 41b orthogonal to the axis I.

[0284] Openings 48, 49 and / or pipes 70, 71 are adapted to be traversed by lubricating fluid from the main lubrication circuit 47 and lubricating fluid from the outlet tank 500''''''.

[0285] The operation of the transmission assembly 3 will now be described starting with the condition that the valve 600 is in the closed configuration and the temperature of the bearing 40 and / or the planetary gear 18 is below a threshold. In this condition, the opening 540 is blocked, and lubricating fluid is prevented from flowing out of the cavity 503.

[0286] When the temperature of planetary gear 18 and / or bearing 40 is equal to or exceeds the threshold, the fusible element 630 melts and flows through the opening 560.

[0287] After the fusible element melts, the elastic device 640 pushes the reciprocating member 610 toward the second position until it no longer obstructs the opening 540, thereby allowing lubricating fluid to flow from the opening 540 to the opening 550.

[0288] The lubricating fluid that has flowed out of opening 550'''''' flows through compartment 37, openings 48, 49 and pipes 70 and 71 in sequence, thereby lubricating bearing 40 and planetary gear 18.

[0289] Reference Figure 22 and Figure 23 The number 3''''''' indicates the transmission component according to the eighth embodiment of the present invention.

[0290] Transmission assembly 3''''''' includes:

[0291] - Rotatably fixed support member 230;

[0292] - A gear 1800, which is rotatable relative to the support 230 about its own axis of rotation M; and

[0293] - Two rolling bearings 1400, 1401, adapted to rotatably support the gear 1800 relative to the support 230.

[0294] Transmission assembly 3''''''' also includes:

[0295] - Gear 1801, which is rotatable about its own axis of rotation and meshes with gear 1800; and

[0296] - Shaft 1802 - only partially shown - gear 1800 is mounted on shaft 1802, or gear 1800 is integrally formed with shaft 1802 and is rotatable about axis M.

[0297] Bearing 1400 includes:

[0298] - Ring 1410, which defines seat ring 1420 and contacts shaft 1802;

[0299] - Ring 1430, which defines a seat ring 1440 facing the seat ring 1420, and is radially spaced from ring 1410 relative to axis M; and

[0300] - Multiple rolling elements 1450, particularly balls, rolling on the seat rings 1420 and 1440.

[0301] Bearing 1401 includes:

[0302] - Ring 1411, which defines seat ring 1421 and is integrally defined by shaft 1802;

[0303] - Ring 1431, which defines a seat ring 1441 facing the seat ring 1421, and is radially spaced from ring 1411 relative to axis M; and

[0304] - Multiple rolling elements 1451 that roll on seat rings 1421, 1441, particularly rollers oriented parallel to axis M.

[0305] In detail, ring 1431 contacts support member 230, and body 1451 is spaced apart from body 1450 parallel to axis M. More specifically, ring 1430 contacts ring 1431 on the side of ring 1431 opposite to support member 230.

[0306] In addition, rings 1430 and 1431 are fixed by rotation.

[0307] In the illustrated embodiment, the bevel gears 1800 and 1801 are bevel gears, and the axis of rotation M is perpendicular to the axis of rotation of the bevel gear 1801.

[0308] Additionally, the transmission assembly 3''''''' forms part of the collector stage of the aircraft 1''''''', and this is not to be construed as limiting in any way.

[0309] Transmission assembly 3''''''' includes:

[0310] - Tank 1500 for lubricating fluid; and

[0311] - Passive holding device 1600, which includes a valve 1600 adapted to prevent lubricating fluid from flowing out of the tank 1500 when the temperature of bearing 1400 and / or bearing 1401 and / or gear 1800 and / or shaft 1802 is below a threshold, and to allow lubricating fluid to flow out when the temperature of bearing 1400 and / or bearing 1401 and / or gear 1800 and / or shaft 1802 is above or equal to the threshold.

[0312] In detail, the can 1500 is rotatably fixed relative to axis M. More specifically, the can 1500 is partially integrated into the support 230 and partially integrated into the ring 1431. According to a variant not shown, the can 1500 is fully integrated into the support 230.

[0313] The tank 1500 includes a compartment 1510 adapted to contain at least a portion of the lubricating fluid in the tank 1500, and a cavity 1530 fluidly connected to the compartment 1510 and adapted to contain a valve 1600. Furthermore, the tank 1500 is preferably filled with lubricating fluid prior to installation. In other words, the tank 1500 is a container for lubricating fluid.

[0314] Cavity 1530 includes:

[0315] - Opening 1540, which fluidly connects compartment 1510 to cavity 1530; and

[0316] - Opening 1550, which is adapted to allow lubricating fluid to flow out from cavity 1530 and thus from tank 1500.

[0317] Preferably, the cavity 1530 has a cylindrical shape, with its axis W perpendicular to the axis M.

[0318] In the illustrated embodiment, the cavity 1530 includes two sections 1530a and 1530b at the support 23 and a section 1530c at the ring 1431.

[0319] Section 1530a extends from opening 1540, and sections 1530a, 1530b and 1530c are adjacent to each other and extend sequentially parallel to axis W.

[0320] In detail, the extension of the cross-section perpendicular to the axis W of segment 1530b is greater than the extension of the cross-section perpendicular to the axis W of segment 1530a. Furthermore, preferably, the extension of the cross-section of segment 1530c is equal to the extension of the cross-section of segment 1530a.

[0321] The 1600 valve can be arranged as follows:

[0322] - A closing mechanism that prevents lubricating fluid from flowing out of tank 1500. Figure 22 );or

[0323] - An openable structure that allows lubricating fluid to flow out of tank 1500 ( Figure 23 ).

[0324] The valve 1600 is adapted to automatically move from a closed configuration to an open configuration when the temperature of bearing 1400 and / or bearing 1401 and / or gear 1800 and / or shaft 1802 exceeds a threshold. Preferably, the valve 1600 is adapted to move from the closed configuration to the open configuration in an irreversible manner.

[0325] Valve 1600 includes:

[0326] - A reciprocating component 1610 capable of sliding within the cavity 1530; and

[0327] - Fusible element 1630, which is adapted to be solid below a temperature threshold and adapted to at least partially melt at the temperature threshold.

[0328] The reciprocating component 1610 slides between a first position and a second position parallel to the axis W. Specifically, the distance between the reciprocating component 1610 and the ring 1430 is greater in the first position than in the second position.

[0329] When the valve 1600 is in the closed configuration ( Figure 22 When the reciprocating component 1610 is in the first position, and the valve 1600 is in the open position ( Figure 23 When ), reciprocating component 1610 is in the second position.

[0330] The reciprocating component 1610 in the first position determines that the opening 1550 is blocked; the reciprocating component 1610 in the second position determines that the opening 1550 is not blocked. Figure 23 In detail, the reciprocating component 1610 only indirectly contributes to the blocking and non-blocking of the opening 1550.

[0331] More specifically, when the valve 1600 is in the closed configuration, the reciprocating element 1610 abuts against the solid fusible element 1630.

[0332] The fusible element 1630 is adapted to hold the reciprocating member 1610 in a first position when it is in a solid state, and is adapted to determine the sliding of the reciprocating member 1610 toward a second position when the fusible element 1630 is at least partially melted.

[0333] The valve 1600 also includes a resilient device 1640 adapted to preload the reciprocating member 1610 toward the second position. In detail, the resilient device 1640 includes a helical spring arranged to contact the reciprocating member 1610 on the side opposite to the fusible element 1630.

[0334] The valve 1600 also includes a sealing element 1650, which is fixed to the reciprocating member 1610 on the side opposite to the fusible element 1630. The sealing element 1650 slides integrally with the reciprocating member 1610 relative to the cavity 1530.

[0335] When the reciprocating element 1610 is in the first position, the sealing element 1650 prevents fluid communication between the opening 1540 and the opening 1550. Figure 22 Conversely, when the reciprocating element 1610 is in the second position, the sealing element 1650 allows fluid communication between the opening 1540 and the opening 1550.

[0336] The solid fusible element 1630 is a cylindrical body adapted to mate with the ring 1430. In the illustrated embodiment, the solid fusible element 1630 is arranged directly abutting the ring 1430. According to an alternative not shown, one or more elements are positioned between the solid fusible element 1630 and the ring 1430.

[0337] The fusible element 1630 is made of a material suitable for melting at or near a threshold temperature. For example, the fusible element 1630 is made of tin or lead or an alloy thereof.

[0338] The cavity 1530 also includes an opening 1560 for the molten material of the fusible element 1630 to flow out of the cavity 1530. In detail, the opening 1560 is arranged at section 1530c.

[0339] The bearing 1400 also includes one or more conduits 1700 passing through the rings 1410 and 1430, parallel to or transverse to the axis W. The conduits 1700 are adapted to be traversed by lubricating fluid.

[0340] The support 230 includes a conduit 1701 that extends from the opening 1550 and is adapted to be traversed by a lubricating fluid.

[0341] Bearing 1401 includes conduit 1702 that fluidly connects conduit 1701 to at least some of conduit 1700. Specifically, conduit 1702 is arranged at ring 1431. According to a variant not shown, conduit 1700 is directly fluidly connected to conduit 1701.

[0342] The operation of the transmission assembly 3''''''' is described below, which begins when the valve 1600 is in the closed configuration and the temperature of the bearing 1400 and / or bearing 1401 and / or gear 1800 and / or shaft 1802 is below a temperature threshold.

[0343] In this case, the sealing element 1650 blocks the opening 1550, and the fusible element 1630 abuts against the ring 1430. Figure 22 ).

[0344] When the temperature of bearing 1400 and / or bearing 1401 and / or gear 1800 and / or shaft 1802 is equal to or higher than the threshold, the fusible element 1630 melts and flows through the opening 1560.

[0345] After the fusible element melts, the elastic device 1640 pushes the reciprocating member 1610 toward the second position until it no longer blocks the opening 1550, thereby allowing lubricating fluid to flow from the opening 1540 to the opening 1550.

[0346] The lubricating fluid that has come out of the opening 1550 flows sequentially through pipes 1701, 1702 and 1700, thereby lubricating bearing 1400 and / or bearing 1401 and / or gear 1800 and / or shaft 1802.

[0347] Reference Figure 24 and Figure 25 The numeral 3'''''''' indicates a transmission assembly according to a ninth embodiment of the present invention. The transmission assembly 3''''''''' is similar to the transmission assembly 3'''''''', and will be described below only in the areas where it differs from the transmission assembly 3''''''; where possible, the same or equivalent parts of the transmission assembly 3''''''''''' will be indicated by the same reference numerals.

[0348] Similar to transmission assembly 3''''''', transmission assembly 3''''''''' includes gears 1800 and 1801, bearings 1400 and 1401, and support member 230. Preferably, transmission assembly 3'''''''' also includes a canister 1500 and a passive retaining device 1600.

[0349] In addition, the transmission assembly 3'''''''' includes:

[0350] - Shaft 1803, gear 1801 is mounted on shaft 1803, or gear 1801 is integrally formed with shaft 1803 and is capable of rotating about a rotation axis N orthogonal to axis M; and

[0351] - Rolling bearing 1402, which is adapted to support the gear 1801 in a manner that allows it to rotate relative to the support 230.

[0352] Bearing 1402 includes:

[0353] - Ring 1412, which defines seat ring 1422 and is integrally defined by shaft 1803;

[0354] - Ring 1432, which defines a seat ring 1442 facing the seat ring 1422 and is radially spaced from ring 1412 relative to axis N; and

[0355] - Multiple rolling elements 1452 that roll on seat rings 1422 and 1442, particularly rollers oriented parallel to axis N.

[0356] In detail, the gear 1801 includes a body 1804 and an internal gear ring 1805 extending from the body 1804.

[0357] Transmission assembly 3'''''''' differs from transmission assembly 3''''''' because it includes:

[0358] - A tank 2500 for lubricating fluid, which is integrated in a gear 1801 and thus rotates relative to axis N; and

[0359] - Passive holding device 2600, which includes a valve 2600 and is adapted to prevent lubricating fluid from flowing out of the tank 2500 when the temperature of bearing 1402 and / or gear 1801 and / or shaft 1803 is below a threshold, and to allow lubricating fluid to flow out when the temperature of bearing 1402 and / or gear 1801 and / or shaft 1803 is above or equal to the threshold.

[0360] The tank 2500 includes a compartment 2510 adapted to contain at least a portion of the lubricating fluid in the tank 2500, and a cavity 2530 fluidly connected to the compartment 2510 and adapted to contain a valve 2600. Furthermore, the tank 2500 is preferably filled with lubricating fluid prior to installation. In other words, the tank 2500 is a container for lubricating fluid.

[0361] Cavity 2530 includes:

[0362] - Opening 2540, which fluidly connects compartment 2510 to cavity 2530;

[0363] - Opening 2550, which is adapted to allow lubricating fluid to flow out from cavity 2530 and thus from tank 2500.

[0364] Preferably, the cavity 2530 has a cylindrical shape, with its axis Q perpendicular to the axis N.

[0365] In the illustrated embodiment, the cavity 2530 sequentially includes:

[0366] - Section 2530a extending from opening 2540;

[0367] - Section 2530b; and

[0368] - Section 2530c.

[0369] In detail, the extension of the cross-section perpendicular to axis Q of segment 2530b is greater than the extension of the cross-section perpendicular to axis Q of segment 2530a. Furthermore, preferably, the extension of the cross-section perpendicular to axis Q of segment 2530c is equal to the extension of the cross-section perpendicular to axis Q of segment 2530a.

[0370] The 2600 valve can be arranged as follows:

[0371] - A closing mechanism that prevents lubricating fluid from flowing out of tank 2500 ( Figure 24 );or

[0372] - Opening mechanism, in which it allows lubricating fluid to flow out from tank 2500 ( Figure 25 ).

[0373] The valve 2600 is adapted to automatically move from a closed configuration to an open configuration when the temperature of the bearing 1402 and / or the gear 1801 and / or the shaft 1803 exceeds a threshold. Preferably, the valve 2600 is adapted to move from the closed configuration to the open configuration in an irreversible manner.

[0374] Valve 2600 includes:

[0375] - Reciprocating component 2610, which is capable of sliding within cavity 2530;

[0376] - Fusible element 2630, which is solid below a temperature threshold and is adapted to melt at the temperature threshold.

[0377] Specifically, the reciprocating component 2610 slides between a first position and a second position parallel to axis Q. Specifically, when the valve 2600 is in the closed configuration ( Figure 24 When the reciprocating component 2610 is in the first position, and when the valve 2600 is in the open position ( Figure 25 When the reciprocating component 2610 is in the second position, the distance parallel to the axis Q between the reciprocating component 2610 and the tooth 1805 is greater in the first position than in the second position.

[0378] The fusible element 2630 is adapted to hold the reciprocating member 2610 in a first position when the fusible element 2630 is in a solid state, and is adapted to determine the sliding of the reciprocating member 2610 toward a second position when the fusible element 2630 is at least partially melted.

[0379] More specifically, when the valve 2600 is in the closed configuration, the reciprocating component 2610 abuts against the solid fusible element 2630. The solid fusible element 2630 also directly abuts against the body 1804. Figure 24 ).

[0380] The valve 2600 also includes a resilient device 2640 adapted to preload the reciprocating member 2610 toward the second position. In detail, the resilient device 2640 includes a helical spring arranged to contact the reciprocating member 2610 on the side opposite to the fusible element 2630.

[0381] The valve 2600 also includes a sealing element 2650, which is fixed to the reciprocating member 2610 on the side opposite to the fusible element 2630. The sealing element 2650 slides integrally with the reciprocating member 2610 relative to the cavity 2530.

[0382] When the reciprocating element 2610 is in the first position, the sealing element 2650 blocks the opening 2550 and prevents fluid communication between the opening 2540 and the opening 2550. Figure 24 Conversely, when the reciprocating element 2610 is in the second position, the sealing element 2650 does not obstruct the opening 2550 and allows fluid communication between the opening 2540 and the opening 2550. Figure 25 Therefore, the reciprocating component 2610 only indirectly contributes to the blocking and non-blocking of the opening 2550.

[0383] The solid-state fusible element 2630 is a cylindrical body that is directly abutting the main body 1804.

[0384] The fusible element 2630 is made of a material suitable for melting at or near a threshold temperature. For example, the fusible element 2630 is made of tin or lead or an alloy thereof.

[0385] The cavity 2530 also includes an opening 2560 for the molten material of the fusible element 2630 to flow out of the cavity 2530.

[0386] Preferably, the gear 1801 further includes an opening 2570 and a conduit 2800, the conduit 2800 extending inside the body 1804 and fluidly connecting the opening 2550 to the opening 2570.

[0387] The operation of transmission assembly 3''''''''' is described below, which is performed when valve 2600 is in closed configuration and the temperature of bearing 1402 and / or gear 1801 and / or shaft 1803 is below a threshold. Figure 24 )start.

[0388] When the temperature equals or exceeds the threshold, the fusible element 2630 melts at least partially, the elastic device 2640 pushes the reciprocating element 2610 toward the second position, and the opening 2550 is not blocked. Therefore, lubricating fluid is allowed to flow from the opening 2540 to the opening 2550.

[0389] The lubricating fluid that has come out of opening 2550 flows sequentially through pipe 2800 to opening 2570 and lubricates gear 1800 and / or 1801 and / or shaft 1803.

[0390] The advantages provided by the transmission component 3; 3'; 3''; 3'''; 3''''; 3''''; 3'''''; 3''''''; 3'''''''; 3'''''''' by examining the characteristics of the transmission component 3; 3'; 3''''''''; 3'''''''' by examining the characteristics of the transmission component 3; 3'; 3'''''''' by examining the characteristics of the transmission component 3; 3'; 3'''''''; 3'''''''' by examining the characteristics of the transmission component 3; 3'; 3''''''; 3'''''''; 3''''''' by examining the characteristics of the transmission component 3; 3'; 3'''; 3''''''; 3''''''' by

[0391] In particular, since the transmission assembly 3; 3'; 3''; 3'''; 3''''; 3''''; 3'''''; 3''''''; 3'''''''' includes passive retaining devices 60; 60'; 501''; 503''', 504'''; 503''''; 503''''; 506''''; 600'''''; 1600; 2600, lubrication of critical components of the transmission assembly can be ensured in an effective manner. In fact, the holding devices 60; 60'; 501''; 503''', 504'''; 503''''; 503''''', 506'''''; 1600; 2600 do not require a power supply of electricity, pneumatic power or hydraulic power to operate, and are calibrated according to the threshold temperature of the part to be lubricated.

[0392] Since the passive holding devices 60; 60'; 501''; 503''', 504'''; 600''''''; 1600; 2600 include a fusible portion that melts at the threshold temperature, or the passive holding devices 503''''; 503''''', 506''''' include a shape memory portion adapted to return to its initial configuration at the threshold temperature, lubricating fluid is effectively discharged from the tanks 50; 500''; 500'''; 500''''; 500''''; 1500; 2500 when the part to be lubricated reaches the threshold temperature.

[0393] Since tanks 50; 500''; 500'''; 500''''; 500''''; 500'''''; 2500 are carried by rotating parts, the outflow of lubricating fluid in an emergency is facilitated by the centrifugal force it experiences during rotation.

[0394] Because the valves 60; 600'''''; 1600; 2600 include elastic devices 64; 640''''''; 1640; 2640, they facilitate the movement of the reciprocating members 61; 610''''''; 1610; 2610 toward a second position in an emergency, where the reciprocating members 61; 610''''''; 1610; 2610 allow lubricating fluid to flow out.

[0395] Finally, it is clear that modifications and variations can be made to the transmission components 3; 3'; 3''; 3'''; 3''''; 3''''; 3'''''; 3''''''; 3'''''''; 3''''''''; 3'''''''''', without departing from the scope of protection defined by the claims.

[0396] In particular, the transmission assembly 3; 3'; 3''; 3'''; 3''''; 3''''; 3'''''; 3''''''; 3'''''''; 3'''''''' can be adapted to transmit motion from one or more turbines to multiple accessory devices, which are designed to provide, for example, the energy required for the operation of airborne equipment.

[0397] In addition to tank 50, transmission assembly 3; 3' may also include:

[0398] - One or more tanks 500'' and associated retaining devices 501''; and / or

[0399] - One or more tanks 500''' and associated retaining devices 503''', 504'''; and / or

[0400] - One or more tanks 500'''' and associated retaining devices 503''''; and / or

[0401] - One or more tanks 500 and associated retaining devices 503, 506; and / or

[0402] - One or more tanks 500'''''' and associated holding devices 600''''''.

[0403] Fusible elements 63; 63'; 504'''; 630''''''; 1630; 2630 may be adapted to melt at temperatures below or above a temperature threshold of the part to be lubricated, for example, depending on the distance and / or assembly characteristics between the fusible element and the part to be lubricated.

[0404] The transmission assembly 3'''''' may include a passive retaining device similar to retaining devices 60' or 501'' or 503''', 504''' or 503'''' or 503''''', 506'''''.

[0405] The tank 500'''''' can rotate integrally with the corresponding planetary gear 18 relative to the corresponding axis I.

[0406] The aircraft 1; 1'; 1''; 1'''; 1''''; 1''''; 1'''''; 1''''''; 1'''''''; 1'''''''' can be a vertical takeoff and landing reversing aircraft or an airplane.

[0407] Some or all components of valves 60; 60'; 600''''''; 1600; 2600 (reciprocating parts 61; 61'; 610''''''; 1610; 2610, striking pin element 62; 62', fusible element 63; 63'; 630''''''; 1630; 2630, elastic device 64; 64'; 640''''''; 1640; 2640, sealing element 65; 1650; 2650) can be combined, integrated, and / or welded together. Specifically, some or all components of valves 60; 60'; 600''''''; 1600; 2600 can be produced by additive manufacturing.

[0408] The valves 60; 600''''''; 1600; 2600 can be accommodated outside the cavities 53; 530''''''; 1530; 2530.

[0409] Alternatively or supplementally, fusible elements 63; 63'; 504'''; 630''''''; 1630; 2630 may be adapted to be in a non-deformable state below a threshold temperature and to deform and / or lose their mechanical properties at temperatures equal to or above the threshold.

Claims

1. A transmission assembly (3, 3', 3'', 3''', 3''''; 3'''''; 3'''''''; 3'''''''') for an aircraft (1; 1''''''; 1''''''''); 3'''''''; 3''''''''') comprising: - At least one component to be lubricated for transmitting motion (18; 40; 1800; 1801; 1400; 1401). - At least one first tank (50; 500; 1500; 2500) suitable for containing lubricating fluid; and - A first passive retaining device (60; 600''''''; 1600; 2600), the first passive retaining device being adapted to prevent the lubricating fluid from flowing out of the first tank (50; 500''''''; 1500; 2500) when the temperature of the component to be lubricated (18; 40; 1800; 1801; 1400; 1401) is below a threshold during use, and to allow the lubricating fluid to flow out from the first tank (50; 500''''''; 1500; 2500) toward the component to be lubricated (18; 40; 1800; 1801; 1400; 1401) when the temperature of the component to be lubricated (18; 40; 1800; 1801; 1400; 1401) is above the threshold during use; The first tank (50; 500; 1500; 2500) is characterized by including at least a first opening (55; 550; 1550; 2550) adapted to allow the lubricating fluid to flow out during use. The first passive holding device (60; 600''''''; 1600; 2600) further includes a valve (60; 600''''''; 1600; 2600) that is at least partially housed inside or outside the first tank (50; 500''''''; 1500; 2500). The valves (60; 600; 1600; 2600) further include: - A first body (61; 610; 1610; 2610), the first body being slidable between a first position and a second position, in the first position, during use, the first body determines that the first opening (55; 1550; 2550) is blocked, and in the second position, the first body determines that the first opening (55; 1550; 2550) is not blocked; and - A fusible element (63; 630''''''; 1630; 2630), said fusible element being adapted to be solid in use below said threshold, and adapted to at least partially melt and / or deform at said threshold; The fusible element (63; 630; 1630; 2630) is adapted to hold the first body (61; 610; 1610; 2610) in the first position when the fusible element is in a solid state during use, and is adapted to determine the sliding of the first body (61; 610; 1610; 2610) toward the second position when the fusible element is at least partially melted during use.

2. The transmission assembly according to claim 1, characterized in that, The transmission assembly includes another component for transmitting motion; The component to be lubricated (18; 40; 1801) is rotatable relative to the other component to transmit motion about a first axis of rotation (A; N; I); The first can (50; 500''''''; 2500) and the component to be lubricated (18; 40; 1801) rotate integrally with respect to the first axis (A; N; I).

3. The transmission assembly according to claim 1 or 2, characterized in that, The valve (60; 600; 1600; 2600) further includes an elastic device (64; 640; 1640; 2640) adapted to elastically preload the first body (61; 610; 1610; 2610) toward the second position.

4. The transmission assembly according to any one of the preceding claims, comprising a planetary gear train (21) adapted to transmit power from a first shaft (22) of the aircraft (1; 1'''''') to a second shaft (11) in use. The planetary gear system (21) includes: - Sun gear (15), which is rotatable about a first axis (A) and adapted to be operably connected to the first shaft (22); - Crown gear (17), which is fixed at an angle relative to the first axis (A); - A plurality of planetary gears (18) that are rotatable about their respective second axes (I) parallel to the first axis (A) and mesh with the sun gear (15) and the crown gear (17) in use; as well as - A planetary gear carrier (30), which is rotatable about the first axis (A), operably connected to the planetary gear (18) and adapted to be operably connected to the second axis (11). The planetary gear carrier (30) includes: - Second body (31), the second body is arranged coaxially with the first axis (A); - A plurality of pins (32) extending along a corresponding second axis (I), and a corresponding planetary gear (18) being rotatably mounted on the pin about the corresponding second axis (I); - A plurality of arms (33) extending radially cantileveredly from the second body (31) and each connecting a corresponding pin (32) to the second body (31); and - A plurality of first rolling bearings (40), the plurality of first rolling bearings being radially positioned between the respective pins (32) and the planetary gears (18).

5. The transmission assembly according to claim 4, characterized in that, The first canister (50; 500'''''') is carried by the planetary gear carrier (30), and the at least one component to be lubricated (18) is the planetary gear (18) and / or the first bearing (40).

6. The transmission assembly according to claim 4 or 5, characterized in that, The first can (50) includes: - The third subject (51); - Multiple attachments (52) that extend radially cantilevered from the third body (51) toward the crown gear (17) relative to the first axis (A); - A compartment (510; 510''''''), said compartment being adapted to contain, in use, at least a portion of the lubricating fluid in the first tank (50; 500''''''); and - At least one cavity (53; 530'''''') which is fluidly connected to the compartment (510; 510''''''); Each of the attachments (52) includes a corresponding cavity (53) and is located between the corresponding arm (33) and the corresponding first bearing (40) parallel to the corresponding second axis (I); The cavity (53; 530'''''') further includes: - A second opening (54; 540''''''), which fluidly connects the compartment (510; 510'''''') to the cavity (53; 530''''''); and - The first opening (55; 550'''''') is adapted to allow the lubricating fluid to flow out from the cavity (53; 530'''''') during use; The first body (61; 610) is capable of sliding within the cavity (53; 530).

7. The transmission assembly according to claim 6, characterized in that, The first opening (55) of the cavity (53) of each of the attachments (52) faces directly toward the corresponding first bearing (40).

8. The transmission assembly according to any one of claims 4 to 6, characterized in that, The first can (500'''''') is radially inside the planetary gear (18) relative to the corresponding second axis (I), and the component to be lubricated (18) is the planetary gear (18) and / or the first bearing (40).

9. The transmission assembly according to claim 1 or 3, comprising: - Rotatably fixed support (230); - A gear (1800) that is rotatable relative to the support (230) about a third axis of rotation (M); as well as - At least one second rolling bearing (1400, 1401), said at least one second rolling bearing being adapted to support the gear (1800) in use in a manner that allows it to rotate relative to the support (230). The first tank (1500) is integrated into the support member (230) and / or fixed to the support member (230).

10. The transmission assembly of claim 9, wherein the second bearing (1400) comprises: - First ring (1410), the first ring defines the first seat ring (1420); - A second ring (1430), the second ring defining a second ring (1440) facing the first ring (1420); and - A plurality of first rolling elements (1450) adapted to roll on the first seat ring (1420) and the second seat ring (1440) in use; The fusible element (1630) in the solid state is adapted to cooperate with the second ring (1430).

11. The transmission assembly according to claim 9 or 10, characterized in that, The second bearing (1400) includes a plurality of first conduits (1700) that extend through the first ring (1410) and / or the second ring (1430) and are adapted to be traversed by the lubricating fluid in use; The support (230) includes a second conduit (1701) adapted to fluidly connect the first opening (1550) to at least some of the first conduits (1700).

12. The transmission assembly according to any one of claims 1 to 3, wherein the lubricated member (1801) for transmitting motion comprises a gear (1801). The gear (1801) further includes: - The fourth subject (1804); - A gear ring (1805), which is fixed to or integrated into the fourth body (1804). The first can (2500) is integrated into the fourth body (1804), and the solid fusible element (2630) is arranged to abut against the fourth body (1804) during use.

13. The transmission assembly according to any one of claims 1 to 8, characterized in that, include: - At least one second tank (500'') suitable for containing lubricating fluid; as well as - A second passive retaining device (501''), adapted to prevent the lubricating fluid from flowing out of the second reservoir (500'') when the temperature of the component to be lubricated (18; 40) is below a threshold during use, and adapted to allow the lubricating fluid to flow out from the second reservoir (500'') toward the component to be lubricated (18; 40) when the temperature of the component to be lubricated (18; 40) is above the threshold during use; The second passive holding device (501'') includes the first housing (501'') of the second can (500''); The first housing (501'') is adapted to melt and / or deform during use when the temperature exceeds the threshold.

14. The transmission assembly according to any one of claims 1 to 8 or 13, characterized in that, include: - At least one third tank (500''') suitable for containing lubricating fluid; as well as - A third passive retaining device (503'''; 504'''), the third passive retaining device being adapted to prevent the lubricating fluid from flowing out of the third reservoir (500''') when the temperature of the component to be lubricated (18; 40) is below a threshold during use, and is adapted to allow the lubricating fluid to flow out from the third reservoir (500''') toward the component to be lubricated (18; 40) when the temperature of the component to be lubricated (18; 40) is above the threshold during use; The third can (500''') includes a second housing (501'''), and the second housing (501''') includes a third opening (502'''); The third passive holding device (503'''; 504''') includes: - An elastic element (503'''), said elastic element being adapted to be arranged in a flat configuration when below said threshold during use and to be elastically preloaded toward a curved configuration; as well as - Another fusible element (504'''), said other fusible element being adapted to be solid in use below said threshold, and adapted to at least partially melt and / or deform at said threshold; The other fusible element (504''') in the solid state is adapted to hold the elastic element (503''') in the flat configuration during use and allow the elastic element (503''') to shift into the curved configuration during use when the other fusible element (504''') melts; The elastic element (503''') in the flat configuration and the other fusible element (504''') in the solid state are adapted to block the third opening (502''') in use. The elastic element (503''') in the curved configuration is adapted to at least partially not obstruct the third opening (502'''), thereby allowing the lubricating fluid to flow out from the third reservoir (500''').

15. The transmission assembly according to any one of claims 1 to 8, 13, or 14, characterized in that, include: - At least one fourth tank (500'''') suitable for containing lubricating fluid; as well as - A fourth passive retaining device (503''''), the fourth passive retaining device being adapted to prevent the lubricating fluid from flowing out of the fourth reservoir (500'''') when the temperature of the component to be lubricated (18; 40) is below a threshold during use, and is adapted to allow the lubricating fluid to flow out from the fourth reservoir (500'''') toward the component to be lubricated (18; 40) when the temperature of the component to be lubricated (18; 40) is above the threshold during use; The fourth can (500'''') includes a third housing (501''''), and the third housing (501'''') includes a fourth opening (502''''); The fourth passive holding device (503'''') includes an element (503'''') made of shape memory material, the element (503'''') being adapted to be arranged in a flat configuration when below the threshold during use, and adapted to be arranged in a curved configuration when at the threshold during use; The element (503'''') in the flat configuration is adapted to block the fourth opening (502'''') during use; The element (503'''') in the curved configuration is adapted not to obstruct at least a portion of the fourth opening (502'''') during use, thereby allowing the lubricating fluid to flow out from the fourth reservoir (500'''').

16. The transmission assembly according to any one of claims 1 to 8 or 13 to 15, characterized in that, include: - At least one fifth tank (500''''') suitable for containing lubricating fluid; as well as - A fifth passive retaining device (503'''''), the fifth passive retaining device being adapted to prevent the lubricating fluid from flowing out of the fifth reservoir (500''''') when the temperature of the component to be lubricated (18; 40) is below a threshold during use, and is adapted to allow the lubricating fluid to flow out from the fifth reservoir (500''''') toward the component to be lubricated (18; 40) when the temperature of the component to be lubricated (18; 40) is above the threshold during use; The fifth can (500''''') includes a fourth housing (501'''''), and the fourth housing (501''''') includes a fifth opening (502'''''); The fifth passive holding device (503''''') includes: - An elastic element (503'''''), adapted to be arranged in a flat configuration when below the threshold during use and preloaded toward a curved configuration; the elastic element (503''''') is at least fixed to the fourth housing (501''''') in the flat configuration; and - An element (506''''') made of shape memory material, the element (506''''') being adapted to engage with the elastic element (503'''''); the element (506''''') being adapted to be arranged in a compressive configuration below the temperature threshold and adapted to be arranged in an extended configuration at the temperature threshold; The element (506'''') in the compression configuration is adapted to hold the elastic element (503''''') in the flat configuration during use; the element (506'''') in the extension configuration is adapted to remove and / or disengage the elastic element (503''''') from the fourth housing (501'''''), thereby allowing the elastic element (503''''') to be arranged in the bending configuration during use; The elastic element (503'''') in the flat configuration blocks the fifth opening (502'''') during use; the elastic element (503'''') in the curved configuration releases the fifth opening (502'''') at least partially during use.

17. The transmission assembly according to any one of claims 4 and 13 to 16, wherein the first bearing (40) comprises: - Third ring (41), which defines a third seat ring (42); - A fourth ring (43), which defines a fourth ring (44) facing the third ring (42); and - A plurality of second rolling elements (45) adapted to roll on the third seat ring (42) and the fourth seat ring (44) during use; The third ring (41) is integral with the corresponding pin (32), and the second can (500''), the third can (500'''), the fourth can (500'''') and / or the fifth can (500'''') are fixed to the third ring (41).

18. An aircraft (1; 1''''''; 1'''''''; 1''''''''), particularly a hovering aircraft, said aircraft comprising a transmission assembly (3, 3'', 3''', 3'''', 3''''; 3''''''; 3''''''''; 3'''''''') according to any one of the preceding claims.

19. A transmission assembly (3'''''', 3''''''') for an aircraft (1' ... - At least one component to be lubricated (1800; 1801; 1400; 1401) used to transmit motion. - At least one tank (1500) suitable for containing lubricating fluid; and - A passive retaining device (1600) adapted to prevent the lubricating fluid from flowing out of the tank (1500) when the temperature of the component to be lubricated (1800; 1801; 1400; 1401) is below a threshold during use, and to allow the lubricating fluid to flow out of the tank (1500) toward the component to be lubricated (1800; 1801; 1400; 1401) when the temperature of the component to be lubricated (1800; 1801; 1400; 1401) is above the threshold during use; - Rotatably fixed support (230); - A gear (1800) that is rotatable about a rotation axis (M) relative to the support (230); as well as - At least one rolling bearing (1400, 1401), said at least one rolling bearing being adapted to support the gear (1800) in use in a manner that allows it to rotate relative to the support (230). The characteristic feature is that the can (1500) is integrated into the support (230) and / or fixed to the support (230).

20. The transmission assembly according to claim 19, characterized in that, The tank (1500) includes at least an opening (1550) adapted to allow the lubricating fluid to flow out during use; The passive holding device (1600) also includes a valve (1600) that is at least partially housed inside or outside the tank (1500). The valve (1600) further includes: A first body (1610) is slidable between a first position and a second position. In the first position, during use, the first body determines that the opening (1550) is blocked; in the second position, during use, the first body determines that the opening (1550) is unblocked. - A fusible element (1630) adapted to be solid in use below the threshold and adapted to at least partially melt and / or deform at the threshold; The fusible element (1630) is adapted to hold the first body (1610) in the first position when the fusible element is in a solid state during use, and is adapted to determine the sliding of the first body (1610) toward the second position when the fusible element is at least partially melted during use.

21. The transmission assembly according to claim 20, characterized in that, The valve (1600) also includes an elastic device (1640) adapted to elastically preload the first body (1610) toward the second position.

22. The transmission assembly according to claim 20 or 21, wherein the rolling bearing (1400) comprises: - First ring (1410), the first ring defines the first seat ring (1420); - A second ring (1430), the second ring defining a second ring (1440) facing the first ring (1420); and - A plurality of rolling elements (1450) adapted to roll on the first seat ring (1420) and the second seat ring (1440) in use; The fusible element (1630) in the solid state is adapted to cooperate with the second ring (1430).

23. The transmission assembly according to claim 22, characterized in that, The rolling bearing (1400) includes a plurality of first conduits (1700) extending through the first ring (1410) and / or the second ring (1430) and adapted to be traversed by the lubricating fluid in use; The support (230) includes a second conduit (1701) adapted to fluidly connect the opening (1550) to at least some of the first conduits (1700).

24. The transmission assembly according to any one of claims 19 to 23, wherein the lubricated member (1801) for transmitting motion includes another gear (1801). The other gear (1801) further includes: - Second subject (1804); - Gear ring (1805), which is fixed to or integrated into the second body (1804); The transmission assembly (3'''''''') is characterized in that it comprises: - Another tank (2500) suitable for containing lubricating fluid; and - Another fusible element (2630), said other fusible element being adapted to be solid in use below said threshold, and adapted to at least partially melt and / or deform at said threshold; The other can (2500) is integrated into the second body (1804), and the other fusible element (2630) in the solid state is arranged to abut against the second body (1804) during use.

25. An aircraft (1'''''', 1''''''''), particularly a hovering aircraft, said aircraft comprising a transmission assembly (3'''''', 3'''''''') according to any one of claims 19 to 24.

26. A transmission assembly (3'') for an aircraft (1''), comprising: - At least one component to be lubricated (18) used to transmit motion; 40）； - At least one tank (500'') suitable for containing lubricating fluid; and - A passive retaining device (501'') adapted to prevent the lubricating fluid from flowing out of the tank (500'') when the temperature of the component to be lubricated (18; 40) is below a threshold during use, and to allow the lubricating fluid to flow out of the tank (500'') toward the component to be lubricated (18; 40) when the temperature of the component to be lubricated (18; 40) is above the threshold during use; The passive holding device (501'') includes the housing (501'') of the can (500''); The housing (501'') is adapted to melt and / or deform during use when the temperature exceeds the threshold.

27. A transmission assembly (3''') for an aircraft (1'''), comprising: - At least one component to be lubricated (18) used to transmit motion; 40）； - At least one tank (500''') suitable for containing lubricating fluid; and - A passive retaining device (503'''; 504'''), the passive retaining device being adapted to prevent the lubricating fluid from flowing out of the tank (500''') when the temperature of the component to be lubricated (18; 40) is below a threshold during use, and to allow the lubricating fluid to flow out of the tank (500''') toward the component to be lubricated (18; 40) when the temperature of the component to be lubricated (18; 40) is above the threshold during use; The can (500''') includes a shell (501'''), the shell (501''') including a first opening (502'''); The passive holding device (503'''; 504''') includes: - An elastic element (503'''), said elastic element being adapted to be arranged in a flat configuration when below said threshold during use and to be elastically preloaded toward a curved configuration; as well as - A fusible element (504'''), said fusible element being adapted to be solid in use below said threshold, and adapted to at least partially melt and / or deform at said threshold; The fusible element (504''') in the solid state is adapted to hold the elastic element (503''') in the flat structure during use and allow the elastic element (503''') to shift into the curved structure during use when the fusible element (504''') melts; The elastic element (503''') in the flat structure and the fusible element (504''') in the solid state are adapted to block the first opening (502''') in use. The elastic element (503''') in the bending configuration is adapted to at least partially not obstruct the first opening (502'''), thereby allowing the lubricating fluid to flow out from the can (500''').

28. A transmission assembly (3'''') for an aircraft (1''''), comprising: - At least one component to be lubricated (18) used to transmit motion; 40）； - At least one tank (500'''') suitable for containing lubricating fluid; and - A passive retaining device (503''''), which is adapted to prevent the lubricating fluid from flowing out of the tank (500'''') when the temperature of the component to be lubricated (18; 40) is below a threshold during use, and to allow the lubricating fluid to flow out of the tank (500'''') toward the component to be lubricated (18; 40) when the temperature of the component to be lubricated (18; 40) is above the threshold during use; The can (500'''') includes a shell (501''''), and the shell (501'''') includes a first opening (502''''); The passive holding device (503'''') includes an element (503'''') made of shape memory material, the element (503'''') being adapted to be arranged in a flat configuration when below the threshold during use, and adapted to be arranged in a curved configuration when at the threshold during use; The element (503'''') in the flat configuration is adapted to block the first opening (502'''') during use; The element (503'''') in the curved configuration is adapted not to obstruct at least a portion of the first opening (502'''') during use, thereby allowing the lubricating fluid to flow out from the can (500'''').

29. A transmission assembly (3') for an aircraft (1'''''), comprising: - At least one component to be lubricated (18) used to transmit motion; 40）； - At least one tank (500 mL) suitable for containing lubricating fluid; and - A passive retaining device (503'''''), which is adapted to prevent the lubricating fluid from flowing out of the tank (500''''') when the temperature of the component to be lubricated (18; 40) is below a threshold during use, and to allow the lubricating fluid to flow out of the tank (500''''') toward the component to be lubricated (18; 40) when the temperature of the component to be lubricated (18; 40) is above the threshold during use; The can (500) includes a shell (501), the shell (501) including a first opening (502). The passive holding device (503''''') includes: - An elastic element (503'''''), adapted to be arranged in a flat configuration when below the threshold during use and preloaded toward a curved configuration; the elastic element (503''''') is at least fixed to the housing (501''''') in the flat configuration; and - An element (506''''') made of shape memory material, the element (506''''') being adapted to engage with the elastic element (503'''''); the element (506''''') being adapted to be arranged in a compressive configuration below the temperature threshold and adapted to be arranged in an extended configuration at the temperature threshold; The element (506'''') in the compression configuration is adapted to hold the elastic element (503''''') in the flat configuration during use; the element (506'''') in the extension configuration is adapted to remove and / or disengage the elastic element (503''''') from the housing (501'''''), thereby allowing the elastic element (503''''') to be arranged in the bending configuration during use; The elastic element (503''''') in the flat configuration blocks the first opening (502''''') during use; the elastic element (503''''') in the curved configuration at least partially releases the first opening (502''''') during use.

30. The transmission assembly according to any one of claims 26 to 29, characterized in that, The transmission assembly includes another component for transmitting motion; The component to be lubricated (18; 40) is rotatable relative to the other component to transmit motion about a first axis of rotation (A; I); The can (500''; 500'''; 500''''; 500''''; 500''''') rotates integrally with the lubricated component (18; 40) relative to the first axis (A; I).

31. The transmission assembly according to any one of claims 26 to 30, comprising a planetary gear train (21) adapted to transmit power from a first shaft (22) of the aircraft (1''; 1'''; 1''''; 1'''') to a second shaft (11) in use: The planetary gear system (21) includes: - Sun gear (15), which is rotatable about a first axis (A) and adapted to be operably connected to the first shaft (22); - Crown gear (17), which is fixed at an angle relative to the first axis (A); - A plurality of planetary gears (18) that are rotatable about their respective second axes (I) parallel to the first axis (A) and mesh with the sun gear (15) and the crown gear (17) in use; as well as - A planetary gear carrier (30), which is rotatable about the first axis (A), operably connected to the planetary gear (18) and adapted to be operably connected to the second axis (11). The planetary gear carrier (30) includes: - First body (31), the first body is arranged coaxially with the first axis (A); - A plurality of pins (32) extending along a corresponding second axis (I), and a corresponding planetary gear (18) being rotatably mounted on the pin about the corresponding second axis (I); - A plurality of arms (33) extending radially cantileveredly from the first body (31) and each arm connecting a corresponding pin (32) to the first body (31); and - A plurality of first rolling bearings (40), the plurality of first rolling bearings being radially positioned between the respective pins (32) and the planetary gears (18).

32. The transmission assembly according to claim 31, wherein the first bearing (40) comprises: - First ring (41), the first ring defines the first seat ring (42); - A second ring (43), the second ring defining a second ring (44) facing the first ring (42); and - A plurality of rolling elements (45) adapted to roll on the first seat ring (42) and the second seat ring (44) in use; The first ring (41) is integral with the corresponding pin (32), and the can (500''; 500'''; 500''''; 500'''') is fixed to the first ring (41).

33. The transmission assembly according to any one of claims 26 to 32, characterized in that, It includes: - At least another container (50) suitable for containing lubricating fluid; and - Another passive retaining device (60'), the other passive retaining device being adapted to prevent the lubricating fluid from flowing out of the other can (50) when the temperature of the component to be lubricated (18; 40) is below a threshold during use, and to allow the lubricating fluid to flow out from the other can (50) toward the component to be lubricated (18; 40) when the temperature of the component to be lubricated (18; 40) is above the threshold during use; The other passive holding device (60') includes a valve (60'), the valve (60') comprising: - Second body (61'), the second body is integral with the other can (50) and includes a cavity (61d'); - Another fusible element (63'), said other fusible element being adapted to be solid in use below said threshold, and adapted to at least partially melt and / or deform at said threshold; The cavity (61d') further includes a second opening (610') and a third opening (611'), the second opening (610') being fluidly connected to the tank (50), and the third opening (611') being adapted to allow the lubricating fluid to flow out from the first cavity (61d'); The other fusible element (63') in the solid state occupies the cavity (61d') in use and is adapted to prevent fluid communication between the second opening (610') and the third opening (611'); the other fusible element (63') is adapted to allow fluid communication between the second opening (610') and the third opening (611') when the other fusible element (63') is at least partially melted in use.

34. The transmission assembly according to claims 31 and 33, characterized in that, The valve (60') includes a resilient device (64'); The elastic device (64') includes an elastic rod (64a') fixed to the planetary gear carrier (30); When the other fusible element (63') is in the solid state during use, the elastic rod (64a') is operably connected to the other fusible element (63'). The elastic rod (64a') is elastically preloaded in use toward the position where it abuts against the pin (32).

35. An aircraft (1''; 1'''; 1''''; 1'''''), particularly a hovering aircraft, said aircraft comprising a transmission assembly (3''; 3'''; 3''''; 3''''') according to any one of claims 26 to 34.

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