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A Study on the Mold System of Bicycles Gear for Driving Safety

주행 안전을 위한 자전거 기어의 프레스금형에 관한 연구

  • 정연승 (유한대학교 금형설계공학과)
  • Received : 2018.09.01
  • Accepted : 2018.09.15
  • Published : 2018.12.31

Abstract

Recently, bicycle has means of effective healthy transportation, and riding the bicycles is considered as popular recreational and sporting activities. Also, the saddle, steering system, driving device and braking device are researched briskly because of consumer's need for driving performance and comfort. Especially, the importance of a cassette responsible for transmission function by transmitting power to the drive shaft through the chain is very focused. The writer conducted structural analysis for the sprocket of each level using the ANSYS widely used for the analysis. Speed shifting performance was enhanced by minimization / simplification of shifting point through a sort of tooth profile of the cassette. By partitioning a clear value type and other shifting point, it has been modified to enable smooth speed-shifting. In addition, as titanium precision forming process, this study studied the molding technique by blanking and dies forging for mass production of the cassette. so it could be expected that the entire drive train would utilize that in the future. The stamping process capability for thin materials for the mass production of the sprockets is applicable to producing automobile parts, so lightweight component production is likely to be possible through that, for the safety of driving.

Keywords

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[Figure 1] 3D model of 4-level sprocket

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[Figure 2] Sprocket modeling and material selection

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[Figure 3] Forming test samples

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[Figure 4] Changed shape of sprocket teeth

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[Figure 5] Tooth profiles

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[Figure 6] Before and after of changed arrangement of sprocket assembly

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[Figure 7] Arrangement of sprocket transmitting point

Sprocket pitch of samples

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Number of teeth at samples

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Mechanical properties

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FEM analysis results of 4-level sprocket

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FEM analysis results of 5-level sprocket

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Spider analysis result

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FEM analysis results of redesigned 4-level sprocket

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FEM analysis results of redesigned 5-level sprocket

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References

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  3. Yong Wang, Desheng Ji, Kai Zhan (2013), "Modified sprocket tooth profile of roller chain drives." Mechanism and Machine Theory, 70:380-393 https://doi.org/10.1016/j.mechmachtheory.2013.08.006
  4. S. Thipprakmas (2011), "Improving wear resistance of sprocket parts using a fine-blanking process." Wear, 271:2396-2401 https://doi.org/10.1016/j.wear.2010.12.015
  5. E. O. Ezugwu, Z. M. Wang (1997), "Titanium alloys and their machinability -a review." Journal of Materials Processing Technology, 68:62-274
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