Abstract— This research is an investigation on the fracture of a helical gear transmission which was to adjust the engine to increase the horsepower. The gears were made of chromium steel JIS-SCr 420. The bending stress and contact stress of the gear tooth are considered to be one of the main contributors for the failure of the gear in a gearbox. Thus, the analysis of stress has become popular as an area of research on gears to minimize or reduce the failure and for optimal design of gears In this paper bending and contact stress are calculated by using analytical method as well as finite element analysis. Bending stress is calculated by using Lewis bending equation and contact stress by using AGMA contact stress equation. Finite element method software package is used to analyze the bending stress and the contact stress. Finally these two methods bending and contact stress results are compared with AGMA equation. The results showed that the gear failed with a fatigue fracture, which the load of contact stress over took the contact strength of the material (1,550 MPa). The summary analysis results can be accorded with the assumption of this research and as an information for a protection of any failure gearing. 
 

Index Terms—Bending stress, Contact stress, FEM, Helical gear

Cite: Visanu Boonmag, Aphinan Phukaoluan, Ongarj Wisesook,  and Ganwarich Pluphrach, "Comparison of Bending Stress and Contact Stress of Helical Gear Transmission Using Finite Element Method," International Journal of Mechanical Engineering and Robotics Research, Vol. 8, No. 1, pp. 99-103, January 2019. DOI: 10.18178/ijmerr.8.1.99-103