United Technologies Corporation

Sikorsky Aircraft Corporation

Locust, Usa, Inc.

Jules G Kish

Charles J Isabelle

Stephen R Sammataro

Yuriy Gmirya

Robert A Stone

William L Noehren

Anthony George Chory

Vincent F Millea

Robert J Durwin

Ralph D Costanzo

Timothy L Krantz

Hugh L Kearney

Michael John Orazietti

Scott Bradley Poteet

J William Box

Jason DeWitt McPeak

Michelle Consolini

Lionel G Webb

A gearbox assembly includes a gearbox housing and a gear located in the housing and rotatable about a central axis. One or more gear shields are fixed in the housing and at least partially surround the gear. The one or more gear shields define a cavity between the gear and the one or more gear shields. The one or more gear shields are configured such that a pumping action is created by the gear rotation to direct gearbox lubricant out of the cavity. A method of scavenging lubricant from a gearbox includes pumping a flow of lubricant circumferentially around a cavity defined between a gear and a gear shield at least partially surrounding the gear via rotation of the gear about a central axis. The flow of lubricant is urged from the cavity into a lubricant outlet. The lubricant is urged through a lubricant channel in an axial direction.

Self scavenging gear shield

A transmission system for use with a microturbine engine that includes an input shaft operably coupled to the output shaft of the microturbine engine. The output shaft of the microturbine engine and the input shaft of the transmission system operate at a rotational speed in a range between 50,000 and 250,000 RPM with an output power between 200 and 5 HP. The transmission system includes a gear train having a first gear that interfaces to a second gear, the first and second gears employing teeth with opposite handed helix-angled surfaces that apply axial forces to the input shaft during both normal operation and start-up operations, which pushes the input shaft toward the output shaft of the microturbine engine. Preferably, the helix-angled surfaces on respective normal drive sides of the teeth produce an axial force during normal operation that will not be overcome with the axial force produced by the mass time acceleration of the first gear. The gear train interfaces to a starter-generator preferably through the second gear. The gear train preferably provides a reduction ratio having a value greater than 24.

Transmission system for use in microturbine-powered applications

A transmission system that is used in conjunction with a microturbine engine for propelling an aircraft body, such as a propeller-based fixed-wing aircraft or a rotor-based vertical lift aircraft, or for a wide variety of other applications. The output shaft of the microturbine engine preferably operates at a rotational speed in a range between 72,000 RPM and 150,000 RPM with an output power between 150 HP and 5 HP (and most preferably operates in an extended range between 50,000 RPM and 200,000 RPM with an output power between 200 HP and 5 HP). The two reduction stages provide a reduction ratio preferably having a value of at least 19, and most preferably greater than 24. The transmission system is of small-size preferably having a maximum diameter less than twelve inches. The two stages of the transmission system may comprise any one (or parts of) of a number of configurations, including an in-line lay shaft configuration, an in-line star-star configuration, an offset star-spur configuration, an offset compound idler configuration, an inline traction-internal gear configuration, and an inline traction-planetary gear configuration. Preferably, the input stage of the transmission system is self-equilibrating such that first shaft can be supported without bearings and is operably coupled to the output shaft of the microturbine engine by an outside diameter piloted spline coupling mechanism. For vertical lift applications, a single traction stage along with a bevel gear assembly or other shaft transmission mechanism can be used to provide the necessary RPM reduction.

Small-size high-speed transmission system for use in microturbine-powered aircraft

A transmission system that is used in conjunction with a microturbine engine for propelling an aircraft body, such as a propeller-based fixed-wing aircraft or a rotor-based vertical lift aircraft, or for a wide variety of other applications. The output shaft of the microturbine engine preferably operates at a rotational speed in a range between 72,000 RPM and 150,000 RPM with an output power between 150 HP and 5 HP (and most preferably operates in an extended range between 50,000 RPM and 200,000 RPM with an output power between 200 HP and 5 HP). The two reduction stages provide a reduction ratio preferably having a value of at least 19, and most preferably greater than 24. The transmission system is of small-size preferably having a maximum diameter less than twelve inches. The two stages of the transmission system may comprise any one (or parts of) of a number of configurations, including an in-line lay shaft configuration, an in-line star-star configuration an offset star-spur configuration, an offset compound idler configuration, an inline traction-internal gear configuration, and an inline traction planetary gear configuration. Preferably, the input stage of the transmission system is self-equilibrating such that first shaft can be supported without bearings and is operably coupled to the output shaft of the microturbine engine by an outside diameter piloted spline coupling mechanism. For vertical lift applications, a single traction stage along with a bevel gear assembly or other shaft transmission mechanism can be used to provide the necessary RPM reduction.

A transmission system for a hybrid aircraft is driven by a plurality of driveshafts and drives a translational propulsion system. Each driveshaft is mounted to a pinion gear which mesh with an upper and lower counter-rotating gear. The upper and lower counter-rotating gears drive a respective upper and lower rotor shaft which powers a counter-rotating rotor system. A first angle is defined between a first and a second driveshaft while a second angle is defined between the second and a third driveshaft. The angle between the driveshafts are a whole number multiple of the formula: &thgr;&equals;(CP/R)*(180/&pgr;). By so angularly locating the driveshafts, proper meshing of the pinion gears and the upper and lower counter-rotating gears is assured and tolerances are less stringent as the support structure is effective designed around optimal location of the driveshafts for gear meshing rather than vice versa.

Transmission for a coaxial counter rotating rotor system

The present invention relates to a flexible bearing assembly for use in a transmission system. The flexible bearing assembly has a gear mounted to a first shaft, first and second pinions connected to a second shaft, and a flexible coupling element connected to the gear and the first pinion. The flexible coupling element is preferably formed by a flexible diaphragm.

Flexible bearing arrangement for double helical pinion

A face gear transmission system divides the input torque into multiple kinematic paths. The first kinematic scheme consists of a drive shaft and driven shaft having a plurality of pinions which contact a primary face gear. The second kinematic scheme consists of two independent symmetrical gear paths. One is a first pinion, a first idler and a first idler face gear and the primary face gear. The other independent gear path is a pinion on the second shaft, the idler, and second idler face gear and the primary face gear. The face gear transmission is especially applicable to rotorcraft having one or more input drive shafts to provide a proprotor transmission system which is relatively small in size and light in weight.

Split-torque face gear transmission

A method for fabricating a split path transmission system that achieves equal torque splitting between the forward and aft split load paths of each gear train thereof at a predefined operating point by providing an intentional timing difference between gears and pinions of the forward and aft split load paths of each gear train of the split path transmission system is disclosed. The method includes the steps of identifying the torque distribution curves of the forward and aft split load paths of one gear train of the split path transmission system. The method further includes a step of selecting a predefined operating point for the split path transmission system wherein equal torque splitting between the forward and aft split load paths of the one gear train is desired. Next, the forward and aft torque distribution curves are analytically modified as required to pass through the predefined operating point. The interception point with the abscissa of the analytically-modified forward or aft torque distribution curve having the steeper slope is then identified to quantify an input torque range. Finally, the timing relationship of the gears and pinions of the split load path represented by the analytically-modified torque distribution curve having the steeper slope is altered to provide an intentional timing difference between the gears and pinions of the forward and aft split load paths, respectively, of the one gear train such that during operation of the split path transmission system the other split load path transmits all torque input to the main rotor shaft over the input torque range.

Method for fabricating a split path transmission system providing equal

A coil spring (10) for an overrunning spring clutch assembly wherein the coil spring (10) includes a crossover coil (20) having a longitudinal crossover gap (24) formed therein, and a dynamic balance weight (40) secured in combination with one of the internally opposed surfaces (24s) of the longitudinal crossover gap (24). The dynamic balance weight (40) is configured such that, when assembled in combination with a central arbor (32) and coaxial clutch members (34) of the overrunning spring clutch assembly, the dynamic balance weight (40) is spaced apart from the central arbor (32) and each of the clutch members (34). Furthermore, the dynamic balance weight (40) is fabricated from a material having a density .rho..sub.BW which is greater than the density .rho..sub.CC of the base material from which the crossover coil (20) is fabricated.

Coil spring for overrunning spring clutches

An isolated ring gear (60) for a planetary gear drive system (12), which isolated ring gear (60) is operative transferring torque loads and reducing the transmission of high frequency vibrations from the planetary pinions (36) of the drive system (12) to an adjacent support (50). The isolated ring gear (60) includes and inner ring segment (62), an outer ring segment (64) and a plurality of spring elements (66) disposed between and integrally formed with the inner and outer ring segments (62, 64). The inner ring segment (62) has a plurality of gear teeth (62.sub.T) for being disposed in intermeshing combination with the teeth (3b.sub.T) of the planetary pinions (36) and the outer ring segment (64) is rigidly affixed to the adjacent support structure (50). The spring elements (66) are operative to transfer torque loads from the inner ring segment (62) to the outer ring segment (64) and, furthermore, provide a torsionally soft load path for reducing the transmission of high frequency vibrations from the inner ring segment (62) to the adjacent support structure (50). The isolated ring gear (60) is fabricated by the steps of: forming a ring-shaped blank of metallic material, grinding a series of gear teeth (62.sub.T) about an inner diameter of the ring-shaped blank and selectively removing material from the ring-shaped blank to form the plurality of spring elements (66), thereby segmenting the blank into the inner and outer ring segments (62, 64). The preferred fabrication method includes wire electro-discharge machining.

Method of making an isolated ring gear for planetary gear drive systems

A coil spring (50) for use in an overrunning spring clutch assembly having a central arbor (16) for centering and supporting the coil spring (50) in an overrunning operating mode. The coil spring (50) includes teaser coils (52) disposed at each end thereof, central coils (54) disposed intermediate the teaser coils (52), and transition coils (56) disposed between and adjoining the teaser coils (52) and the central coils (54). The coil spring (50) is characterized by each of the transition coils (56) having an interface surface (56.sub.IS) being substantially complementary to a corresponding external bearing surface (16.sub.ES) defined by the central arbor (16) of the spring clutch assembly. Such substantially complementary relationship limits the radial deflection of the transition coils (56) in the overrunning operating mode, thereby reducing vibratory bending stresses in the coil spring (50).

An isolated ring gear (60) for a planetary gear drive system (12), which isolated ring gear (60) is operative transferring torque loads and reducing the transmission of high frequency vibrations from the planetary pinions (36) of the drive system (12) to an adjacent support (50). The isolated ring gear (60) includes and inner ring segment (62), an outer ring segment (64) and a plurality of spring elements (66) disposed between and integrally formed with the inner and outer ring segments (62, 64). The inner ring segment (62) has a plurality of gear teeth (62.sub.T) for being disposed in intermeshing combination with the teeth (32b.sub.T) of the planetary pinions (36) and the outer ring segment (64) is rigidly affixed to the adjacent support structure (50). The spring elements (66) are operative to transfer torque loads from the inner ring segment (62) to the outer ring segment (64) and, furthermore, provide a torsionally soft load path for reducing the transmission of high frequency vibrations from the inner ring segment (62) to the adjacent support structure (50).

Isolated ring gear for planetary gear drive systems

A stacked compound planetary gear train for an upgraded powertrain system for a helicopter that provides an increased reduction ratio to accommodate the increased horsepower output of the augmented powerplant system while concomitantly providing a baseline RPM output to the main rotor shaft. The stacked compound planetary gear train includes a driving sun gear, a set N of primary planetary pinions, a plurality of secondary planetary pinions, a compound drive shaft supporting each respective primary and secondary planetary pinion combination, a fixed ring gear interacting with the secondary planetary pinions, and a planetary carrier assembly disposed in rotatable combination with the compound drive shafts and operative to provide the output of the stacked compound planetary gear train to the main rotor shaft of the helicopter. The set N of primary planetary pinions includes a plurality N/2 of upper primary planetary pinions and a plurality N/2 of lower primary planetary pinions. The upper and lower primary planetary pinions are disposed in a staggered, biplanar relationship wherein each upper primary planetary pinion overlaps the immediately adjacent lower primary planetary pinions. The stacked compound planetary gear train functions as the third stage reduction gearing in the upgraded powertrain system which includes input modules for receiving the increased horsepower output of an augmented powerplant system. The input modules include first stage reduction gearing for coupling power from the input modules to a main transmission assembly gearing. Second stage reduction gearing of the main transmission assembly couples power to the stacked compound planetary gear train to drive the sun gear thereof.

Stacked compound planetary gear train for an upgraded powertrain system

A self-scavenging, hybrid lubrication subsystem for a main transmission gearbox includes a sump fabricated as an integral extension of the lower portion of the gearbox wherein the sump dynamic fluid level is above the gearbox bottom. The interior sidewall of the lower gearbox is modified to include a cylindrical segment having a first radius, a throat segment having a second radius, and a transition segment contiguous with the cylindrical and throat segments. The radial discontinuity between the cylindrical and throat segments defines a nozzle inlet that directs the outflow of lubricating medium in the gearbox bottom to the sump via a nozzle. The outflow end of the nozzle is positioned above the sump dynamic fluid level. Housed within the lower gearbox is a planetary gear train that includes an annular planetary carrier plate having a deflection plate mounted thereto. The periphery of the carrier plate and the cylindrical and throat segments in combination form primary and restricted flow channels. Interaction between the deflection plate and the gearbox bottom exerts a viscous pumping action on the lubricating medium in the gearbox bottom causing it to flow outwardly into the primary and restricted flow channels. Interaction between the periphery of the rotating carrier plate and the structurally-modified sidewall exerts a viscous pumping action on the lubricating medium in the flow channels causing it to flow therethrough. Substantially all of the lubricating medium flowing through the primary flow channel is diverted through the nozzle to the sump.

Self-scavenging, hybrid lubrication subsystem

A fail safe, segmented drive shaft system includes a segment support assembly (16) comprising a ball bearing (26), for primary rotation, disposed within a journal bearing (28), for secondary rotation, which is disposed within an elastomeric damper (30) that has a vibration probe (34) placed in it for failure detection, and a coupling assembly (18) comprising a flexible diaphragm (66, 67) for primary, flexible coupling between segments and gear teeth (72, 73) which engage for secondary coupling upon failure of the diaphragm (66, 67). The teeth are not concentric with the rotational axis, so vibration indicates failure of the primary flexible coupling.

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Milford, CT, United States of America

Jules G Kish