Inline 12:1 Gearbox
Project Overview
Design of compound gear train to achieve 12:1 reduction ratio within 22 millimeter casing. Gear combinations computationally established and then validated and selected using gear stress analysis. Casing modeled for selected configuration.
Project Objective
Design a 12:1 reduction ratio gearbox that fits within a 22 mm cylindrical package. Use gears of standard pressure angles and pitches. The gearbox would be driven by a motor w/ nominal of torque 6.96 mNm at a nominal speed of 7060 rpm.
Specifications
- Reduction ratio of 12:1 (Input:Output)
- Package Size: 22mm OD, 20mm Length
- Nominal Motor Input: Torque: 6.96mNm Speed: 7060rpm
- Gear Material: 1045 Steel
- Desired Lifespan: 1000 hours
Technical Process
1. Define Design Degrees of Freedom
The design degrees of freedom were identified as pitch, number of teeth, face width, and individual stage ratios.
2. Determine Stage Permutations
Used prime factorization in MATLAB, to find standard ratios that reached a 12:1 reduction for 4,5 and 6 stage configurations.
3. Engineering Calculations
Gear constants for stress calculations selected. Bending and surface stress and strength compared in MATHCAD.
4. Selection and Modeling
Optimal design selected and modeled with bearings and casing. Input and output shaft aligned through canting.
Outcome and Impact
- Optimized solution was identified, validated and modeled.
- Through this project experience was gained in gear train design and analysis practices.
