Surface Pitting Fatigue Life of Noninvolute, Low-Contact-Ratio Gears

Abstract

Spur gear endurance tests were conducted to investigate the surface pitting fatigue life of nonivolute gears with low numbers of teeth and low contact ratios for use in advanced applications. The results were compared with those a standard involute design with a low number of teeth. The gear pitch diameter was 8.89 cm (3.50 in.) with 12 teeth on both gear designs. Test conditions were an oil inlet temperature of 320 K an oil outlet temperature of 350 K a maximum Hertz stress of 1.49 Gpa (216 ksi), and a speed of 10,000 rpm. The following results were obtained: The noninvolute gear had a surface pitting fatigue life approximately 1.6 times that of the standard involute gear of a similar design. The surface pitting fatigue life of the 3.43-pitch AISI 8620 noninvolute gear was approximately equal to the surface pitting fatigues the same load but at a considerably high maximum Hertz stress.

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Document Details

Document Type
Technical Report
Publication Date
Jan 01, 1990
Accession Number
ADA229182

Entities

People

  • Dennis P. Townsend

Organizations

  • National Aeronautics and Space Administration

Tags

Communities of Interest

  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Army Aviation
  • Diameters
  • Dynamic Loads
  • Elements
  • Fatigue Life
  • Fatigue Tests (Mechanics)
  • Gear Teeth
  • Gears
  • Lubricants
  • Lubrication
  • Materials
  • New York
  • Standards
  • Stresses
  • Surface Roughness
  • Test And Evaluation
  • Vapor Pressure

Fields of Study

  • Materials science

Readers

  • Tribology (the study of the boundary interaction between sliding surfaces, lubrication, wear and friction).