Influence of lubricating oil additives on the pitting fatigue life of thrust needle bearing

Toshihiko Ichihashi, Hiroshi Fujita, Takashi Yonekawa, Susumu Matsumoto

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

In recent years, the demand of lower viscosity in transmission fluids has been strongly required to improve fuel efficiency. However, fatigue life of gears and bearings usually deteriorates by decreasing the viscosity of lubricating oil. Especially the impact on needle bearings that are mostly used in automatic transmissions is significant. Therefore it is very important to study about the fatigue life of needle bearing, and authors have previously reported about the influence of lubricating oil additive on a radial type. In this paper, fatigue life of a thrust needle bearing was examined using several simply formulated oils and the effect of physical properties of tribofilm on rubbed surfaces, such as composition, thickness and hardness of film, were analyzed by using microscopes and a nano-indenter. Through the bearing pitting test and the analysis of film properties, it was found that the softer and smooth film provides longer fatigue life as shear stress during rubbing may not easily accumulate in the films and the bearing materials.

Original languageEnglish
Pages (from-to)128-135
Number of pages8
JournalToraibarojisuto/Journal of Japanese Society of Tribologists
Volume55
Issue number2
Publication statusPublished - 2010

Keywords

  • Additives
  • Automatic transmission fluid
  • Gear lubricants
  • Nano-indenter
  • Pitting test
  • Thrust needle bearing
  • Tribofilm

ASJC Scopus subject areas

  • Mechanical Engineering
  • Mechanics of Materials
  • Materials Chemistry
  • Surfaces, Coatings and Films
  • Surfaces and Interfaces

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