Research Papers

A High Ratio Power Dense Planetary Drive for Rotorcraft Applications

[+] Author and Article Information
Xiaolan Ai

Fellow ASME
Timken Technology Center,
The Timken Company,
Canton, OH 44706
e-mail: xiaolan.ai@timken.com

Curtis Orkin

Engineering Manager
Timken Aerospace Transmission,
The Timken Company,
Manchester, CT 06045
e-mail: curtis.orkin@timken.com

Randy Kruse

Precision Gear Specialist
Timken Technology Center,
The Timken Company,
Canton, OH 44706
e-mail: randy.kruse@timken.com

PowerGear is gear analysis software developed by Drive System Technology, Inc.

WindowsLDP is a Window based Load Distribution Program for gear analysis, developed by Ohio State University Gear lab.

Contributed by the Power Transmission and Gearing Committee of ASME for publication in the JOURNAL OF MECHANICAL DESIGN. Manuscript received November 14, 2012; final manuscript received August 23, 2013; published online December 18, 2013. Assoc. Editor: Avinash Singh.

J. Mech. Des 136(2), 021010 (Dec 18, 2013) (10 pages) Paper No: MD-12-1558; doi: 10.1115/1.4025967 History: Received November 14, 2012; Revised August 23, 2013

Epicyclic geartrains are known to provide high power density and have become the geartrain of choice for the main power flow in virtually all rotorcraft designs. This paper presents a unique compound planetary design targeting a helicopter main gearbox transmission application. The design significantly improves power density over conventional geartrains through its innovative planet gear load-sharing configuration along with the utilization of high-performance materials for gears and bearings. Design studies were conducted comparing the power density of this new design to a baseline gearbox design. The results of these studies demonstrate an estimated 38% power density improvement over the baseline configuration. Of the total improvement, 86% is attributed to the novel load-sharing configuration while 14% is attributed to utilization of advanced materials and processes.

Copyright © 2014 by ASME
Topics: Stress , Bearings , Design , Gears
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Grahic Jump Location
Fig. 1

Compound double planetary concept (from Ref. [5])

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Fig. 2

Gear train diagram of TPD MGB (BP1, BP2: bevel pinion 1 and bevel pinion2; BG: bevel gear; DS: drive sun gear; IS: idler sun gear; LP: large planet gear; SP: small planet gear or simple idler planet gear; PC: planet carrier; RG: ring gear)

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Fig. 3

Gear train assembly of TPD MGB

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Fig. 4

Force balance diagram, (a) the reference design, force balance diagram, (b) TPD MGB design with complete floating small planet in the compound planet gear, and force balance diagram, (c) TPD MGB design with partially floating small planet in the compound planet gear

Grahic Jump Location
Fig. 5

First configuration of TPD MGB design, single point pivotal support of compound planet gears.

Grahic Jump Location
Fig. 6

Second configuration of TPD MGB design, two-point flexible support of compound planet gears

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Fig. 7

Planet carrier structural design and FEM results for the first configuration

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Fig. 8

Planet carrier structural design and FEM results for the second configuration



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