Design Basics for Spur and Helical Gears - September 10, 2024

Course Rationale/Students Course Designed to Serve: 

This course would be of interest to high level gear grind operators, inspectors and quality assurance people who need to better understand why and how gear designs are optimized and how to interpret non-standard gear geometry.  They can also gain insight on how improper finishing techniques can contribute to pre-mature gear failures.  Entry level gear designers, process and manufacturing engineers can develop a basic understanding of gear geometry terms and variables.  Gear manufacturing project managers can develop a better understanding of time required to design and optimize a gearset that is cost effective and meets or exceeds application expectations.

Learning Objectives:

• Discuss aspects of gear tooth fatigue loading and typical failure modes as a basis for gear designs which exceed target design fatigue life
• Understand the various form of drive loads
  • Prime movers and suggested Safety Factors
  • Constant load applications
  • Variable load/duty cycle applications
• Ability to start with customer supplied gear drive application specification and develop an optimized gear design which meets or exceeds application and performance requirements
• Review gear geometry terminology and design optimization variables beyond information available in Machinery’s Handbook, apply optimization tools currently used in industry
  • Basic Normal Plane Geometry factors – NDP, NPA, Helix Angle, Tooth Size
  • Transverse Rolling Plane Performance variables – Profile Shift, Material, Heat Treatment, Accuracy, High Contact Ratio gear geometry and efficiency
  • Rating factors – Tooth Bending S. F., Tooth Contact S. F., Micro Pitting S. F.
  • Additional performance enhancing processes – shot peen, isotropic finishing
• Calculate contact and bending Safety Factors as (Material and Design allowable loads) divided by (application loads) for a target design life.
• Learn how to fit a new gear ratio into existing housing and center distance
• This course is focused on gear design, but reviews functionality of over 20 related drive components and design related processes
• Apply design tools and gear performance enhancements to optimize
  • Rating
  • Operating noise level
  • Efficiency
  • Gear mesh contact
  • Lubrication
• Discuss gear drive design process steps, time, and costs from receipt of customer application specifications through design, prototype development/testing to manufacturing and shipping production units which meet or exceed customer expectations
• Work through two real life examples developing optimized spur and helical gearsets which exceed customer application specifications