Gearbox and turbine engine with geared fan

Abstract

A gearbox (10) includes: a carrier (16) having a central axis and forward and aft walls with respective forward an aft coaxial bores; a pin received in the bores, and secured against axial movement; an inner race mounted on the pin between the forward and aft ends, and secured against axial movement relative to the carrier (16); a planet gear mounted for rotation about the pin, wherein a cylindrical interior surface of the planet gear defines an outer race surrounding the rollers, wherein either the inner race or the interior surface of the planet gear defines at least two axially-spaced apart annular raceways; a plurality of generally cylindrical rollers made of a ceramic material disposed in each of the raceways, between the inner and outer races; a sun gear mounted for rotation about the central axis and engaged with the planet gear; and a ring gear engaged with the planet gear.

Description

Background technique [0001] The present invention relates generally to a planetary gearbox and, in particular, to a carrier support device and bearings for a planetary gearbox. [0002] Planetary gearboxes are often used in aircraft engines to transmit power, for example, to drive propellers or fans for power turbines. Gearboxes for aircraft applications must be lightweight, capable of transmitting high torque loads and highly reliable. From a technical point of view, the system-level reliability of the gearbox is the biggest challenge. [0003] In operation, the planetary gears in the gearbox transmit high loads into the carrier, causing the gearbox's bearings and gears to shift and misalign. To prolong commercial lifetime, these deflections and misalignments must be minimized. [0004] It is known to support a gearbox carrier centrally using spherical bearings to transfer loads at an axial midpoint in the carrier. This enables isolation of the torque fingers connecting t...

AI Technical Summary

Problems solved by technology

However, working ball joints with moving parts are subject to wear and slack, and their presence will result in increased gearbox complexity

[0005] Also, using traditional steel bearings (e.g. M50 steel alloy or similar) will reduce system level life due to the number of bearings in the gearbox

[0006] Ceramic rolling elements are known to provide longer life than steel rollers, however, they are used in the form of spherical or spherical rollers which are not axially compliant and therefore not suitable for some helical gear configurations

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