Transactions of Materials Processing (소성∙가공)

The Korean Society for Technology of Plasticity and materials processing (한국소성∙가공학회)
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A Study on Development of Cold Forward Extrusion Process for Helical Gears of Automotive Transmissions

자동차 변속기용 헬리컬 기어의 냉간전방압출 공정 개발에 관한 연구

  • Received : 2011.08.05
  • Accepted : 2011.10.06
  • Published : 2011.11.01
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Abstract

The application of helical gears in crucial parts of automotive transmissions has been steadily increasing due to their higher power transfer performance compared to spur gears. However, the traditional gear manufacturing methods such as hobbing and deburring require large cycle times with expensive production lines so that there have been intensive efforts trying to manufacture gears via forging processes. Although forging processes for spur and bevel type gears have been developed on the practical level, the manufacturing of helical gears is still dependent on the traditional cutting process. Therefore, this paper seeks to develop a cold forward extrusion process for the helical gear with the pitch diameter of 43.5mm and a helix angle of $18.4^{\circ}$. A forward extrusion process was used due to the relatively small diameter of the target geometry. The material deforming behavior influenced by the die geometry was examined by using CAE analysis. Finally, it was found that the helical gear manufactured by the developed extrusion process satisfied the dimensional accuracy and mechanical characteristics for automotive transmissions.

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References

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