A method for servicing a gas turbine engine includes disassembling a bearing compartment, providing access from a forward side of the gas turbine engine to a gearbox contained within said bearing compartment. The gas turbine engine provides a core flow path that extends from the forward side aftward in a core flow direction. The method includes servicing a component located within the bearing compartment. A method for servicing a gas turbine engine includes providing access from a forward side of a front center body assembly, and servicing a component located within a bearing compartment aft of the front center body assembly. The gas turbine engine includes a seal package located aft of a bearing package. A front wall is mounted to the front center body support and is removable from a front center body support to access at least one of the gearbox, the bearing package and the seal package.

Gas turbine engine front center body architecture

A method of assembling an epicyclic gear train includes the steps of providing a unitary carrier having a central axis that includes spaced apart walls and circumferentially spaced apart apertures provided at an outer circumference of the carrier. Gear pockets are provided between the walls and extend to the apertures, and a central opening in at least one of the walls. A plurality of intermediate gears is inserted through the central opening and move the intermediate gears radially outwardly into the gear pockets to extend through the apertures. A sun gear is inserted through the central opening. The plurality of intermediate gears is moved radially inwardly to engage the sun gear. A gear reduction is also disclosed.

Method of assembly for gas turbine fan drive gear system

A planetary gear system and a method of fabricating same. The planetary gear system includes at least one planet gear, at least one planet pin receiving the at least one planet gear, and a carrier. The carrier itself includes at least one carrier opening for accommodating the at least planet gear, at least one planet pin opening for receiving the at least one planet pin, and at least one flex portion within a wall of the carrier for providing enhanced compliance to the carrier in response to force directed on the at least one planet gear.

Compliant carrier wall for improved gearbox load sharing

An example method of controlling performance of gearbox of a gas turbine engine includes establishing a gear characteristic of a plurality of double helical gears each disposed about a respective axis in a gearbox. Performance of the plurality of double helical gears is controlled by selecting a circumferential offset distance between a first plurality of gear teeth spaced apart from a second plurality of gear teeth on each of the plurality of double helical gears in response to the established gear characteristic.

Turbine engine gearbox

A planetary gear system ( 1 ) includes: a sun gear ( 5 ) having external teeth; a ring gear ( 9 ) having internal teeth; at least one planet gear ( 7 ) having external teeth meshed with the external teeth of the sun gear and the internal teeth of the ring gear. The planet gear ( 7 ) has, at its outer circumferential face, the external teeth which are formed of a pair of sets of teeth aligned in an axial direction and an annular groove ( 17 ) which is formed between the pair of sets of teeth. The planetary gear system ( 1 ) further includes: a fixed support shaft ( 23 ) provided for each of the at least one planet gear ( 7 ) and configured to rotatably support the planet gear ( 7 ) via a bearing, the bearing including a pair of rolling element rows ( 72 ) aligned in the axial direction; an oil supply path (LP) through which lubricating oil is supplied, at an inner side of the planet gear ( 7 ), to the pair of rolling element rows ( 72 ); and an oil discharge path (oil outlet 91 ) which extends through the planet gear ( 7 ) and through which the lubricating oil is discharged to the annular groove ( 17 ) from space between the pair of rolling element rows ( 72 ) which are provided at the inner side of the planet gear ( 7 ).

Planetary gear system and gear reducer

A planetary gear reduction system has a sun gear, a plurality of planet gears, a ring gear, and a planet carrier. The planet carrier has a first plate supporting one ends of planet shafts supporting the planet gears, a second plate supporting the other ends of the planet shafts, and a cylindrical drum connecting the first and second plates. The first plate has first portions supporting the one ends of the planet shafts; second portions connecting the first plate to the drum, the first and second portions being provided alternately in a circumferential direction; first cutouts each defined between the neighboring first and second portions, the first cutouts each extending radially inwardly from a circumferential edge thereof to a position adjacent a circle passing centers of the planet shafts; and second cutouts each defined radially inward of the second portion and between the neighboring two first portions, the second cutouts each extending radially inwardly from a first region outside the circle and a second region inside the circle.

Planetary gear reduction system

This apparatus includes: a sun gear having external teeth; planetary gears, each having external teeth and configured to be meshed with the sun gear; planetary shafts, each being a rotation shaft of the planetary gear; a ring gear having internal teeth and configured to be meshed with the planetary gears; and a planetary carrier including an annular base plate and an annular back plate. The planetary carrier supports the planetary shafts between the annular base plate and the annular back plate and determines a relative position between planetary gears. The annular base plate is integrally formed with one end of the planetary shaft to support the one end. The annular back plate supports the other end of the planetary shaft. At least one of the planetary shaft and the planetary carrier has lower stiffness in its part adjacent to the one end of the planetary shaft than stiffness of its part adjacent to the other end thereof.

Planetary reduction gear apparatus

PROBLEM TO BE SOLVED: To provide a manufacturing method and machining device for a face gear that can lower the cost of a high-speed and heavy-load speed change gear for a helicopter transmission and the like. SOLUTION: The machining device for a face gear wheel comprises a cutting means for feeding a milling cutter 11A with a straight or near-straight tooth shape in a radial direction of a face gear wheel 3 while adjusting the pressure angle of the face gear wheel 3 to a proper value, and a grinding means for feeding a disklike grinding wheel in a radial direction of the face gear wheel 3 while adjusting the pressure angle of the face gear wheel 3 to a proper value. The cutting and grinding work manufactures the face gear wheel 3.

Manufacturing method and machining device for face gear wheel

PROBLEM TO BE SOLVED: To reduce cost of a speed change device of high speed and high load by executing topological cutting while adjusting so that face gear wheel pressure angle becomes a correct value, by the use of a milling cutter having tooth profile of straight line or similar to a straight line. SOLUTION: In a face gear, a straight tooth profile changing pressure angle at respective positions in the radial direction, a small bow shaped curved tooth profile, or a curved tooth profile curved inside and outside against a reference straight line is formed by topological cutting. When the straight tooth profile or the tooth profile similar to a straight line is manufactured by a face gear machining device 10, a milling cutter having the straight tooth profile or the tooth profile similar to a straight line is used, and cutting is executed so that the pressure angle of the face gear wheel becomes a correct value by adjusting the angle of a C1 axis according to the respective positions of the Z-axis. COPYRIGHT: (C)2000,JPO

Face gear set, manufacture of face gear wheel, and machining device thereof

Reducing the fluid dynamic power loss for increasing speed is critical for the development of highly efficient high-speed aircraft engine gearing. In this study, the fluid dynamic loss was experimentally performed using a precise friction loss management technique along a vacuum being drawn on the gearbox. The experimental fluid dynamic loss could be classified as either “oil jet acceleration loss and oil reacceleration loss based on the conservation law of momentum for a point mass” or “oil churning loss and windage loss based on the conservation law of momentum for an incompressible continuum.” Windage loss and oil dynamic loss (i.e., the summation of oil jet acceleration loss, oil reacceleration loss, and oil churning loss) were modeled to develop equations for a loss prediction. The equations of the windage loss are pressure loss of flow passing through the side clearance of the gears and energy loss caused by the vortex generation in the cavity between tooth valleys. Oil dynamic loss was determined by multiplying the oil jet acceleration loss by an empirical coefficient. The results of the loss prediction equations agree with the experimental results, demonstrating the validity of the proposed model of the fluid dynamic loss.

Hirofumi Akahori

Papers

Planetary gear reduction system

Planetary reduction gear apparatus

Manufacturing method and machining device for face gear wheel

Face gear set, manufacture of face gear wheel, and machining device thereof

Classification and Modeling of Fluid Dynamic Loss in Aeroengine Transmission Gears