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.

A mechanical reduction gear for a turbomachine, in particular for an aircraft, the reduction gear including a sun gear, a ring gear, planet gears which are meshed with the sun gear and the ring gear, hydrodynamic bearings for guiding the planet gears in rotation, these bearings being carried by a planet carrier and including cylindrical bodies which are engaged in the planet gears and which are configured so as to be supplied with oil and so as to form guiding oil films between the bodies and the planet gears, wherein each of the planet gears is guided by two hydrodynamic bearings independent of each other and disposed on either side of the plane.

A mechanical reduction gear for a turbomachine, in particular for an aircraft, the reduction gear including a sun gear, a ring gear, planet gears which are meshed with the sun gear and the ring gear, hydrodynamic bearings for guiding the planet gears in rotation, these bearings being carried by a planet carrier and including cylindrical bodies which are engaged in the planet gears and which are configured so as to be supplied with oil and so as to form guiding oil films between the bodies and the planet gears, wherein each of the planet gears is guided by two hydrodynamic bearings independent of each other and disposed on either side of the plane.

A mechanical gearbox for turbomachine, in particular for aircraft. The gearbox includes a sun gear including an external toothing, a ring gear including an internal toothing, and planet gears which are meshed with the sun gear and the stationary ring gear. The planet gears are carried by a movable planet carrier and each having external toothings of different diameters. The movable planet carrier includes a movable ring gear which carries an internal toothing and which is independent of the stationary ring gear, each of the planet gears being meshed with the sun gear and the stationary and movable ring gears.

A planetary gearbox is provided that includes a sun gear, a plurality of planet gear assemblies, each planet gear assembly having a main gear meshed with the sun gear, a fore lateral gear and an aft lateral gear disposed on opposite sides of the main gear and rotating therewith, a planet carrier rotatably supporting at least some of the planet gear assemblies, and at least one fore ring gear meshed with the fore lateral gears, at least one aft ring gear meshed with the aft lateral gears, wherein one of the sun gear, the planet carrier, and the ring gears is configured to be operatively connected to an input, one is configured to be operatively connected to an output, and rotation of a remaining one is limited.

In one embodiment of the present disclosure, there is provided a planetary gear system. The planetary gear system includes a split double helical ring gear having a first ring gear with first helical ring teeth and a second ring gear with second helical ring teeth, a split double helical sun gear having a first sun gear with first helical sun teeth and a second sun gear with second helical sun teeth, a sun gear coupler coupling the first sun gear and the second sun gear; and a single-piece double helical planet pinion having a first helical planet teeth portion and a second helical planet teeth portion, where the first helical planet teeth mesh with the first helical sun teeth and the first helical ring teeth, and the second helical planet teeth mesh with the second helical sun teeth and the second helical ring teeth.

A planetary gearbox includes a ring gear accommodated in a housing part, the ring gear particularly has on its radially outer surface, in particular its radially outer side, an annular groove, the annular groove, in particular a circumferential annular groove in the circumferential direction, and a spring element is accommodated in the annular groove, which projects at least partially into an annular groove introduced into the housing part.

Speed reduction gear for an aircraft turbomachine. The reduction gear has a main axis and planet carrier having a cage and a cage carrier, a sun gear located in the cage and centred on the main axis, an annular row of planet gears arranged around the main axis and the sun gear and meshed with the sun gear, and a ring gear arranged around the axis and the cage and meshed with the planet gears. The cage and the cage carrier are connected to each other by connections whose bending flexibility is optimised.

A gearbox assembly for a gas turbine engine comprises a planetary gearbox having at least one ring gear and at least one planet gear, which exerts a force on the ring gear in the direction of a force vector as it rolls on said ring gear; and a holding device for fastening the at least one ring gear on another structure, having a first section, which extends in the axial direction on one side of the force vector and/or of a straight-line extension thereof, and having a second section, which extends in the axial direction on the other side of the force vector and/or of the straight-line extension thereof. A gas turbine engine and a method for producing a gearbox assembly are furthermore made available.

There is provided a mechanical paradox planetary gear mechanism, including: a sun gear configured to be rotatable together with rotation of an input shaft; a plurality of first planetary gears arranged around the sun gear at equal intervals, and configured to rotate about their own axes while revolving around the sun gear in a state in which the first planetary gears mesh with the sun gear; a first internal gear arranged around the plurality of first planetary gears, and configured to mesh with the plurality of first planetary gears; a second internal gear arranged in the same axis as the first internal gear; and a plurality of second planetary gears respectively arranged on the same axes as the plurality of first planetary gears, and configured to mesh with the second internal gear.