Department of Mechanical Engineering

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Design and Modeling of Epicyclic Gear Train for
Electro-Mechanical Actuator
Department of Mechanical Engineering
Company Aeronautical Development Establishment
(ADE), DRDO, Bangalore
Suman Chandrawat 2001498 Group 03
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Organization Details

• Established in January 1959.
• Major contributor to the Light Combat Aircraft
  (LCA) development programs.
• Develops Aeronautical Systems and Technologies to
  meet the current and future requirements of the
  Indian Armed Forces.

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• Thrust areas
• Targets, Drones and (Remotely Piloted Vehicle)
  RPVs.
• Flight simulation for RD and development of
  simulators.
• Flight research.
• Air armament.

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• Core Areas of work
• Design and development of unmanned
• Aerial vehicles
• Design and development of systems for
• Combat Aircraft
• Flight Simulation

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Main products of the ADE - I

• Unmanned Aerial Vehicles
• Lakshya Pilot less target aircraft
• Nishant Remotely Piloted Aircraft
• LER-UAV (Long endurance and range unmanned air
  vehicle) (Rustom)

Pilot less Target Aircraft Lakshya
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Main products of the ADE II

• Flight Simulation
• Light Combat Aircraft

Light Combat Aircraft
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Divisions of ADE
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Project Details

• Designing an epicyclic gear train for an
  electro-mechanical actuator
• Modeling of the designed gear train using
  Pro-Engineering software

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Project 1 Design an Epicyclic gear train for an
electro-mechanical actuator

• Electro-Mechanical Actuators

Epicyclic gear set
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Motion Transmission in Epicyclic gear train
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Epicyclic gear train Design

• Gear train Analysis
• Torque Analysis
• Load Analysis
• Bending stress analysis
• Surface Stress Analysis
• Safety factors for Bending and fatigue strengths.
• Bearing Selection

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• Assumptions
• Efficiency 70
• Planetary gear set module, m 0.8
• Sector gear set module, m 1.5
• Overall speed ratio, R 172.8 (? 174)
• Speed ratio across planetary gear sets, R1 R2
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• Speed ratio across sector gear set, Rs 4.8
• Pressure angle ? 20? for all gears.

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Gear train Analysis
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Torque Analysis Results
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Load Analysis Results
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Bending stress analysis

• Basic Lewis Equation
• ?b Wt / (F m Y Kv)
• Where,
• ?b Bending Stress
• F Face width
• Y Lewis Form Factor
• Kv Dynamic Factor
• m module

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Bending stress analysis results
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Surface Stress Analysis

• Buckingham equation for surface stresses in gear
  teeth
• ?c Cp (Wt CaCmCsCf) / (DFICv)
  1/2
• Where, ?c Surface stress
• Cp Elastic Coefficient
• Ca Application Factor
• Cm Load Distribution Factor
• Cs Size Factor
• Cf Surface Finish Factor
• I Surface Geometry Factor
• Cv Dynamic Factor

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Surface stress analysis results
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Safety factors for bending strength

• Corrected Bending Fatigue strength
• Sfb KL Sfb
• KT KR
• Safety Factor
• Nb Sfb / ?b

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Safety factors for fatigue strength

• Corrected fatigue strength for gears is given as
• Sfc CLCHSfc/CTCR
• Nc Sfc / ?c2
• Where,
• Sfc Uncorrected surface
• fatigue strength
• CL Surface life factor
• CH Hardness ratio factor
• CT Temperature Factor
• CR Reliability factor

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Bearing Selection

• Basis of selection load and shaft speed.
• GRW miniature ball bearings of given sizes were
  selected.

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Project 2 Modeling of the designed gear train

• Software used Pro-Engineering.
• Modeling of individual parts and assembly.

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Pro E model of the assembly
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Results

• Gear train designed is safe against any kind of
  dynamic failure.
• Compactness requirements are satisfied.
• Model assembly precisely displays the gear train
  designed.