Robustness of polyisobutylene for friction coefficients between bearing surfaces of bolted joints

Shinji Hashimura, Toshiumi Miki, Takefumi Otsu, Kyoichi Komatsu, Shota Inoue, Shuhei Yamashita, Yuya Omiya

Research output: Contribution to journalArticle

Abstract

In bolted joints, clamp force must be accurately controlled to secure their reliability. However, the clamp force varies widely in each tightening because friction coefficients at thread surfaces and bearing surfaces vary in each tightening due to lubricants, configuration error of bolts, surface roughness, and surface hardness, among other things. In this study, we investigated the robustness of polyisobutylene and ISO VG46 machine oil during the tightening process for several parameters of tightening conditions. We especially focused on variations of the friction coefficient between bearing surfaces at an appropriate target clamp force of M8 bolt/nut assemblies and change rates of the friction coefficients from the middle to the end of the appropriate target clamp force. Results showed that the friction coefficients at the target clamp force varied widely if ISO VG46 machine oil was used as a lubricant. In contrast, the variations of the friction coefficients in which polyisobutylene was used for tightening were small. Results also showed that the friction coefficients invariably decreased about 20% from the middle to the end of the target clamp force if ISO VG46 machine oil was used for the lubricant. However, if polyisobutylene was used, the friction coefficients were almost constant for all tightening instances.

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Bearings (structural)
bolted joints
polyisobutylene
Bolted joints
clamps
Clamping devices
coefficient of friction
Friction
lubricants
Lubricants
bolts
Oils
oils
Bolts
Bolt tightening
Nuts (fasteners)
threads
assemblies
surface roughness
hardness

Keywords

  • Bolt tightening
  • bolt/nut assembly
  • clamp force
  • friction coefficient
  • lubricant
  • machine oil
  • polyisobutylene
  • robustness

ASJC Scopus subject areas

  • Mechanical Engineering
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films

Cite this

Robustness of polyisobutylene for friction coefficients between bearing surfaces of bolted joints. / Hashimura, Shinji; Miki, Toshiumi; Otsu, Takefumi; Komatsu, Kyoichi; Inoue, Shota; Yamashita, Shuhei; Omiya, Yuya.

In: Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology, 01.01.2019.

Research output: Contribution to journalArticle

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AU - Inoue, Shota

AU - Yamashita, Shuhei

AU - Omiya, Yuya

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