Study on Methodology to Increase Fatigue Limit of Gears

  1. Prof. Dr.-Ing Lothar Wagner Chairman of ICSP8
  1. Kotoji Ando1,
  2. Katsuyuki Matsui2 and
  3. Hirohito Eto2

Published Online: 7 FEB 2006

DOI: 10.1002/3527606580.ch3

Shot Peening

Shot Peening

How to Cite

Ando, K., Matsui, K. and Eto, H. (2003) Study on Methodology to Increase Fatigue Limit of Gears, in Shot Peening (ed L. Wagner), Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim, FRG. doi: 10.1002/3527606580.ch3

Editor Information

  1. TU Clausthal, Institut für Werkstoffkunde und Werkstofftechnik, Agricolastr. 6, D-38678 Clausthal-Zellerfeld, Germany

Author Information

  1. 1

    Yokohama National University, Yokohama-shi, Japan

  2. 2

    Isuzu Motors Ltd., Kawasaki-shi, Japan

Publication History

  1. Published Online: 7 FEB 2006
  2. Published Print: 12 MAY 2003

ISBN Information

Print ISBN: 9783527305377

Online ISBN: 9783527606580



  • shot peening;
  • improvement of the fatigue limit;
  • gears


The authors conducted a study focusing on the following points: (a) What is the process of fatigue fracture and what is the resistance factor in each stage? (b) What stress ratio (R) can be applied to automotive components? (c) Why does the fatigue limit start decreasing when hardness reaches some level? Is there any way by which the decrease can be inhibited? (d) How can a large compressive residual stress be introduced to a material with 700 HV or more? As a result of this study, it was found that the number of components subjected to cyclic loading with positive stress ratios (R > 0) is unexpectedly high among automotive components such as gears and springs. Therefore, after working closely on the above four points concentrating on the R > 0 components, the following results for improvement of the fatigue limit were proposed: (1) Increase the hardness of materials as high as possible. (2) Introduce compressive residual stress as high and deep as possible. (3) Decrease the grain size as much as possible. (4) Grind the surface region of components to remove early stage fatigue damage such as extrusion and intrusion, and stage I fatigue crack. (5) Heal the stage I fatigue crack during service if possible. In this paper, the fatigue limit range of a gear was improved considerably, simply and economically, using above methods (1), (2) and (3) together.