A gas turbine engine including a first frame including a first mount member defining a stiffness K.sub.1; a second frame including a second mount member defining a stiffness K.sub.2 and a third mount member defining a stiffness K.sub.3; and a gear assembly. The gear assembly includes a first rotatable component, a second rotatable component, and a torque transfer component. The first mount member is coupled to the first rotatable component. The second mount member is coupled to the second rotatable component. The third mount member is coupled to the torque transfer component. The stiffness K.sub.1 is less than or equal to 10% of the stiffness K.sub.3.

An electric drive unit includes an electric motor, a differential assembly, and a double-helical gearset positioned between and interconnecting the electric motor and the differential assembly and adapted to transfer rotational motion from the electric motor to the differential assembly, the double-helical gearset including a driving double-helical gear rotationally mounted onto a transfer shaft of the electric motor and including a right-hand helix, a left-hand helix and a gap extending circumferentially between the right-hand helix and the left-hand helix, and a driven double-helical gear rotationally mounted onto a housing of the differential assembly and including a right-hand helix, a left-hand helix and a gap extending circumferentially between the right-hand helix and the left-hand helix, and a park gear positioned within the gap between the right hand helix and the left hand helix of one of the driving double-helical gear and the driven double-helical gear, wherein one of the driving double-helical gear and the driven double-helical gear is axially moveable.

A device for driving an integrated generator from an accessories relay box of a turbomachine. The device includes first and second electric motors arranged to transfer electric power from one to the other, one or more controllers configured for controlling said electric motors, and an epicyclic reduction gear train. The gear train includes a first element intended to be coupled to the accessories relay box, a second element intended to be coupled to the generator, and a third element driven to rotate by said first electric motor. The control means are configured to modify the speed of rotation of the third element in such a way that the second element is driven to rotate at a constant speed.

A transmission device for splitting torque between two coaxial gears, in particular for a planetary gearing for aeronautic applications, has a motion input member and two transmission members, which are coaxial and have respective shafts provided with gears at an axial end and respective external flanges, at the opposite axial end; the two flanges are axially facing and placed abutting against each other, and are fixed to the motion input member so as to split the torque transmitted from the motion input member between the two flanges; one of the two shafts is axially hollow and houses, with radial clearance, an intermediate portion of the other shaft; the latter is formed by at least two pieces which are coaxial and fixed to each other.

An epicyclic gear train comprising a sun gear, an outer ring gear, and a plurality of planet gears carried by a common planet carrier. The planet carrier comprises a support and a plurality of spindles carried by the support, each spindle having a carrier segment extending away from the support to a distal end, each planet gear being arranged around a the carrier segment. Each distal end is separated from another distal end that is adjacent thereto by a distance, and the epicyclic gear train includes a holder system for maintaining the distance within a predefined range regardless of the force applied to each spindle.

An epicyclic gear train comprising a sun gear, an outer ring gear, and a plurality of planet gears carried by a common planet carrier. The planet carrier comprises a support and a plurality of spindles carried by the support, each spindle having a carrier segment extending away from the support to a distal end, each planet gear being arranged around a the carrier segment. Each distal end is separated from another distal end that is adjacent thereto by a distance, and the epicyclic gear train includes a holder system for maintaining the distance within a predefined range regardless of the force applied to each spindle.

A planetary gear set, for a servomotor system, and including rotary components mounted in at least one assembly configuration, within a case, and producing a speed ratio of the planetary gear set, which is determined by this assembly configuration, between an input member and an output member. The rotary components allow changes in assembly configuration. Each assembly configuration produces a specific predetermined speed ratio. The invention is usable for servomotor systems.

A transmission device to divide torque between gears. The device comprising a coaxial motion input member and transmission members and comprising shafts having gears at an axial end. Flanges which project radially outwards from the shafts, at the opposite axial end with respect to the gears, are axially facing and arranged abutting against each other, and are fixed to the motion input member to divide the torque transmitted by the motion input member between the flanges. The second shaft being axially hollow. The first shaft comprising a first intermediate portion having an outside diameter smaller than the inside diameter of the second shaft and housed at least with radial clearance in the second shaft. The flanges comprise respective portions configured to deform under the action of forces acting between the motion input member and the gears to enable a fluctuation of the shafts with respect to an axis.

A geared turbofan engine with a sun shaft driving a sun gear of planetary gearbox. The sun shaft having a front section proximal to the gearbox and a rear section distal from the gearbox. The outer diameter of the front section of the sun shaft is smaller than the outer diameter of the rear section of the sun shaft. The front section of the sun shaft having between two and four undulant sections, wherein each undulant section having at least one axial part extending in axial direction of the sun shaft and two diaphragm parts on either side of the at least one axial part extending in radial direction outward, the at least one axial part of the undulant section having an inner diameter smaller than the outer diameter of the front section of the sun shaft.

A gas turbine engine including a first frame including a first mount member defining a stiffness K.sub.1; a second frame including a second mount member defining a stiffness K.sub.2 and a third mount member defining a stiffness K.sub.3; and a gear assembly. The gear assembly includes a first rotatable component, a second rotatable component, and a torque transfer component. The first mount member is coupled to the first rotatable component. The second mount member is coupled to the second rotatable component. The third mount member is coupled to the torque transfer component. The stiffness K.sub.1 is less than or equal to 10% of the stiffness K.sub.3.