Abstract: A mechanical gearbox for aircraft includes a sun gear with an external toothing, a ring gear with an internal toothing, and planet gears which are meshed with the sun gear and the ring gear and which each have a first toothing of average diameter D32 meshed with the toothing of the sun gear, and a second toothing of average diameter D28, different from D32, meshed with the internal toothing of the ring gear. The planet gears are guided by hydrodynamic bearings which each include a first smooth guiding surface extending at least partly under the first toothing, and a second smooth guiding surface extending at least partly under the second toothing.

Abstract: A sun gear for a mechanical reduction gear of a turbine engine, in particular for aircraft, the sun gear having a general annular shape about an axis and comprising at the outer periphery thereof, a meshing gearing with planet gears of the reduction gear, and at the inner periphery thereof, splines for coupling with an input shaft of the reduction gear, characterised in that the sun gear has a staged profile in axial cross-section, and preferably comprises an annular recess opening radially inwards and configured to receive at least one oil jet.

Abstract: A mechanical gearbox for an aircraft turbomachine includes a sun gear having an axis (X) of rotation, a ring gear around the sun gear, and planet gears meshed with the sun gear and the ring gear. Each planet gear has a first toothing meshed with the sun gear and a second toothing meshed with the ring gear. The first toothing includes a series of upstream teeth and a series of downstream teeth located on either side of a plane (H) perpendicular to the axis (X) of rotation of the sun gear. The second toothing includes a series of upstream teeth and a series of downstream teeth located on either side of said plane (H) and separated from one another by said first toothing, these teeth being parallel to one another and to the axis (Y) of rotation of the planet gear.

Abstract: A mechanical reduction gear for turbomachine, in particular for aircraft. The reduction gear includes a sun gear having an axis of rotation, a ring gear which extends around the sun gear, planet gears which are meshed with the sun gear and the ring gear and which each includes a first toothing and a second toothing each including two series of teeth located on either side of a median plane, each of the planet gears being centred and guided in rotation by bearings, including an upstream bearing interposed axially between the series of upstream teeth of the second toothing and the plane, and a downstream bearing interposed axially between the series of downstream teeth of the second toothing and the plane.

Abstract: The present invention relates to an oil transfer device (1) for lubricating a planet carrier, movable in rotation, of an epicyclic gear train for a turbomachine, the device (1) extending around an axis (A) and having: an annular casing (11) which extends around the axis (A), the casing (11) comprising a plurality of oil feed grooves (14), axially juxtaposed, each having an oil ejection opening configured to lead radially to a lubrication circuit of the planet carrier to be lubricated, the device (1) being characterized in that one of the oil feed grooves (14) is a high-pressure oil feed groove (14), called a high-pressure groove (14a), and another of the other oil feed grooves (14) is a low-pressure oil feed groove (14), called a low-pressure groove (14b), axially juxtaposed to the high-pressure groove (14a), the grooves (14) being arranged axially along the axis (X) so that the oil is able to be transferred axially from the high-pressure groove (14a) to the low-pressure groove (14b).

Abstract: The invention concerns a process for the assembly of an epicyclic or planetary gear train of a planet gear carrier comprising one or more bores, each of the bores being intended to receive a pivot (18), the process comprising the following steps: a) manufacturing of at least one pivot (18) comprising a real axis (46) distinct from a theoretical axis; b) measuring the position of a real axis of each of said one or more bores of the carrier; c) for each bore of the carrier, mounting a pivot (18) in said bore and orienting it angularly so that the eccentricity of the pivot (18) at least partially makes up for the eccentricity of said bore.

Abstract: A mechanical reduction gear of a turbomachine, in particular of an aircraft. The reduction gear includes a sun gear, a ring gear surrounded by a ring gear carrier, and planet gears meshed with the sun gear and the ring gear. The ring gear carrier includes an axial abutment on which the ring gear is configured to bear, and helical external splines which are engaged in complementary internal splines of the ring gear carrier and which are configured to cooperate by sliding with the internal splines so as to force the ring gear to be held against the abutment in operation.

Abstract: A device includes a central sun gear with a rotation axis X, a ring gear extending about the axis X and the sun gear, and a planetary carrier supporting an annular row of planet gears arranged between the sun gear and the ring gear. Each of the planet gears may be rotationally guided by at least one bearing extending about a tubular support with an axis Y of the planetary carrier. The tubular support includes an inner cavity for receiving oil and substantially radial through-orifices for the passage of oil from the inner cavity to the at least one bearing. The least one bearing may include two bearings mounted coaxially and adjacently around the support. The bearings may include cages with substantially similar diameters of which the facing peripheral edges are shaped to guide the oil supplying the bearings radially outwards with respect to the axis Y.

Abstract: The invention concerns a process for the assembly of an epicyclic or planetary gear train from at least one pivot (18) and a planet gear carrier (20) comprising one or more bores, each of said bores being intended to receive a pivot (18), the process comprising the following steps: a) measuring the position of a real axis of each of said at least one pivot (18) and of said one or more bores of carrier (20); b) dividing each of said pivots (18) into n angular sectors i1 . . . iq . . . in extending about the theoretical axis of said pivot and dividing each of said holes of the carrier (20) into k angular sectors j1 . . . jl . . .

Abstract: The present disclosure relates to the lubrication of a planet-carrier for a mechanical reduction gear of a turbine engine, for example of an aircraft. The planet-carrier includes a cage defining an internal housing configured to receive a central sun gear with an axis of rotation X, and an annular row of planet gears arranged around the sun gear. The cage includes two annular walls that are radial with respect to the axis X, and connected to one another at their outer periphery by a cylindrical wall. At least one of the radial walls has orifices for mounting the planet gears, and the cylindrical wall has through-holes for the passage of the gearings of the planet gears so that they may engage with a gearing of the ring gear, which is configured to extend around the planet gears and the cage.

Abstract: A planetary gearset having a first planet gear, a second planet gear, and pinion gears. The pinion gears mesh with the first planet gear and with the second planet gear, and each pinion gear is pivotally mounted around a shaft. A pinion gear carrier supports each shaft. Each shaft has a radially inner cylindrical portion mounted on the pinion gear carrier, a radially outer cylindrical portion about which the pinion gear is pivotally mounted and a flange extending radially from the radially outer cylindrical portion. The radially outer periphery of the flange is mounted on the pinion gear carrier. The radially outer cylindrical portion and the radially inner cylindrical portion are connected to each other by a radially extending connecting zone.

Abstract: A lubricating oil distributor for a mechanical reduction gear of a turbomachine, in particular of an aircraft, includes a body of generally annular shape around an axis X and includes first and second independent oil circuits. The first oil circuit has a first oil inlet connected by a first chamber to several oil outlets distributed on the body around the axis X. The second oil circuit has a second oil inlet connected by a second chamber to several oil outlets distributed on the body around the axis X. The first and second chambers extend circumferentially around the axis X at different diameters, wherein the first and second oil circuits are formed in the body and are respectively a recovery circuit and an oil supply circuit for toothing of the reduction gear.

Abstract: Device of the reduction gear or differential type for a turbine engine of an aircraft. A central sun gear and a row of planet gears, each of the planet gears are rotationally guided by at least one bearing extending around a tubular support. The tubular support includes an inner cavity for the reception of oil and through-orifices for the passage of oil of the tubular support to the at least one bearing. A member for circulating the oil is mounted in the cavity and includes at least one oil duct intended to be connected to an oil supply. The oil is intended to flow from the at least one duct into the inner cavity to form an oil film in contact with said tubular support, and to flow through the orifices.

Abstract: A planetary gearset having a first planet gear, a second planet gear, and pinion gears. The pinion gears mesh with the first planet gear and with the second planet gear, and each pinion gear is pivotally mounted around a shaft. A pinion gear carrier supports each shaft. Each shaft has a radially inner cylindrical portion mounted on the pinion gear carrier, a radially outer cylindrical portion about which the pinion gear is pivotally mounted and a flange extending radially from the radially outer cylindrical portion. The radially outer periphery of the flange is mounted on the pinion gear carrier. The radially outer cylindrical portion and the radially inner cylindrical portion are connected to each other by a radially extending connecting zone.

Abstract: A mechanical reduction gear for a turbomachine, in particular for an aircraft, this reduction gear including a sun gear having an axis of rotation, a ring gear which extends around the sun gear and which is configured to be fixed in rotation around the axis, planet gears which are in mesh with the sun gear and the ring gear and which are held by a planet carrier which is configured to be fixed or in rotation around the axis, each planet gear including a first toothing of average diameter D1 for the meshing with the sun gear, and a second toothing of average diameter D2, different from D1, for the meshing with the ring gear, wherein the first and second toothings of each planet gear include herringbone teeth and are symmetrical with respect to a plane perpendicular to the axis and passing substantially in the middle of the planet gear.

Abstract: The invention relates to the lubrication of a planet-carrier for a mechanical reduction gear of a turbine engine, in particular of an aircraft, said planet-carrier comprising a cage defining an internal housing intended to receive a central sun gear with an axis of rotation X, and an annular row of planet gears arranged around the sun gear, said cage comprising two annular walls that are radial with respect to said axis X, and connected to one another at their outer periphery by a cylindrical wall of axis X, at least one of these radial walls comprising orifices for mounting the axes of said planet gears, and the cylindrical wall comprising through-holes for the passage of the gearings of the planet gears so that they may engage with a gearing of the ring gear, which is intended to extend around the planet gears and the cage.

Abstract: A turbine engine mechanical reduction gear, for example, of an aircraft, the reduction gear comprising: a sun gear having an axis of rotation; a ring gear which extends around the sun gear and which is configured to be immobile in rotation about the axis; planetary gears which are meshed with the sun gear and the ring gear and which are supported by a planetary carrier which is configured to be mobile in rotation about the axis; at least one lubrication oil distributor which comprises a stator portion immobile in rotation and a rotating integral rotor portion of the planetary carrier; and an annular oil deflector which is integral with the ring gear, wherein the stator portion of the distributor is integral with the deflector.

Abstract: A planetary gear train speed reduction gear planetary carrier (130) assembly and an elastically deformable annular member (160), for a turbine engine, in particular for an aircraft. The planetary carrier (130) has a general annular shape about an axis X. The annular member (160) extends about the axis X, and is fixed to the planetary carrier and configured to be fixed to a stator element (162) of the turbine engine ensuring a flexible connection between the planetary carrier and the stator element. The planetary carrier carries a series of protruding teeth (180) extending substantially radially outwards with respect to the axis X. Each of these teeth has first opposite side faces (180a, 180b) extending into planes passing through the axis X capable of engaging by abutment in the circumferential direction with the stator element. A vibration absorption system is inserted between the first faces and the stator element.

Abstract: A sun gear for a mechanical reduction gear of a turbine engine, in particular for aircraft, the sun gear having a general annular shape about an axis and comprising at the outer periphery thereof, a meshing gearing with planet gears of the reduction gear, and at the inner periphery thereof, splines for coupling with an input shaft of the reduction gear, characterised in that the sun gear has a staged profile in axial cross-section, and preferably comprises an annular recess opening radially inwards and configured to receive at least one oil jet.

Abstract: The present disclosure relates to the lubrication of a planet-carrier for a mechanical reduction gear of a turbine engine, for example of an aircraft. The planet-carrier includes a cage defining an internal housing configured to receive a central sun gear with an axis of rotation X, and an annular row of planet gears arranged around the sun gear. The cage includes two annular walls that are radial with respect to the axis X, and connected to one another at their outer periphery by a cylindrical wall. At least one of the radial walls has orifices for mounting the planet gears, and the cylindrical wall has through-holes for the passage of the gearings of the planet gears so that they may engage with a gearing of the ring gear, which is configured to extend around the planet gears and the cage.