Paper Title:
Failure Analysis of a Herringbone Gear

Herringbone gears are extensively used in numerous engineering applications including gearboxes. Premature failures of such gears could lead to many serious consequences such as process downtime and late delivery which are critically important in this day and age of intense competition. This paper reports the results of failure investigation of a herringbone gear in a reduction gearbox used in a hot rolling steel re-bar mill in Thailand. The gear fractured after only 24 hours of service. The fractured gear was inspected visually and macroscopically, and all critical dimensions were measured. Chemical compositions of the materials were analysed. Fracture surfaces and microstructure of gear material were examined, and microhardness measured. Stress analysis was performed using finite element methodology. It was found that the premature failure of the gear, which appeared as a longitudinal crack, was due to excessive stress. The crack originated at the root of the keyway. Careful examination revealed that there was a slight misalignment between the key and the keyway which resulted in excessive stress. The lesson learned from this failure is that manufacturing defects, however slight, could lead to premature failures of key components such as gears, and could be very costly. It is recommended that apart from proper designs of components, good manufacturing practices are also necessary to minimize the chance of premature failures.

Key Engineering Materials (Volumes 462-463)
Edited by
Ahmad Kamal Ariffin, Shahrum Abdullah, Aidy Ali, Andanastuti Muchtar, Mariyam Jameelah Ghazali and Zainuddin Sajuri
S. Netpu, P. Srichandr, "Failure Analysis of a Herringbone Gear", Key Engineering Materials, Vols 462-463, pp. 366-371, Jan. 2011
Online since
January 2011
US$ 28,-
Authors: Guo Jun Wang, Mei Hua Jiang, Shi Shun Zhu, An Tao Xu
Abstract:Bending fatigue is one of the main failure modes of gears. The method of gear fatigue design was discussed in many papers. Most of them are...
Authors: You Tang Li, Bo Chen, Rui Feng Wang
Abstract:Based on elasticity theory, the stress field and stress intensity factor of gear crack are discussed. The effect of friction coefficient and...
Authors: Yan Qi Li, Ming Tao Liu, Guang Cai Tian
Chapter 10: Materials Forming
Abstract:This paper is aimed to analyse contact stress of ring-plate indexing cam mechanism which is a new type of indexing cam mechanism. A contact...
Authors: You Dong Ye, Zhe Bo Zhou
Chapter 1: Mechanical Science and Engineering
Abstract:In this paper, a cylinder involute gear model is established in AUTOCAD2007 software. SAT file format is imported in the ANSYS software and...
Authors: Jing Luo, Mutellip Ahmat, Qiang Gao, Li Chao Ren
Chapter 2: Mechanical Engineering and Engineering Design
Abstract:In this paper, the precise 3D model of the wind power increasing gear was set up by based on the parametric designing method of Pro/Program,...