• Title/Summary/Keyword: S-G wheel

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A Study on the Development of High Performance Grinding Wheel for the Difficult-to-Grind Materials (난삭재의 고능률 연삭을 위한 연삭숫돌의 개발에 관한 연구)

  • 조기수;이종한;손기락
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1995.04b
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    • pp.118-123
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    • 1995

  • A new grindignwheel was developed for the high performance gfinding of difficult-to-grind materials. Te grinding performance (such as grinding forces, grinding ratio, and surface roughness of ground surface) of the newly developed wheel was evaluated through experiments. Experimental results show that the performance of the newly developed wheel is superior to conventional alumina wheel and comparable to the S-G wheel.

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Microstructure and Transformation Characteristics with Cooling Rate in Cu-Al-Ni Based SMA Ribbons Fabricated by Melt-Spinning (Cu-Al-Ni계 형상기억리본 제조시 냉각속도에 따른 미세조직 및 변태특성)

  • Lee, Y.S.;Jang, W.Y.;Lee, E.G.
    • Journal of the Korean Society for Heat Treatment
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    • v.13 no.4
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    • pp.265-271
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    • 2000

  • The microstructural change and transformation characteristics with cooling rate i.e. wheel speed were investigated in 82.8wt%Cu-12.8wt%Al-4.3wt%Ni SMA ribbons fabricated by melt-spinning. The thickness and width of ribbon were decreased with increasing wheel speed, while the uniformity of it was improved. At same wheel speed, the grain size of the contact surface of ribbon was smaller than that of free surface. The mean grain size was decreased with increasing wheel speed, resulted in obtaining grains with $3{\mu}m$ in mean diameter in the wheel speed of 30 m/s. However, micro-voids and cracks at grain boundary could be observed at higher wheel speed. $M_s$ and $A_s$ temperatures were decreased, and $M_s{\sim}M_f$ and $A_s{\sim}A_f$ temperature ranges were broadened with increasing wheel speed. All the ribbons were retained the ordered $D0_3$ due to rapid cooling, the volume fraction of it was increased with increasing wheel speed.

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Optimisation of Rolling Stock Wheelset Life through Better Understanding of Wheel Tyre Degradation

  • Vermeij, I.;Bontekoe, T.;Liefting, G.;Peen, J.
    • International Journal of Railway
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    • v.1 no.3
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    • pp.83-88
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    • 2008

  • Since the 1990's the fleet of the Dutch Railways showed a dramatic decrease in wheel tyre life. This lifetime reduction led to an unacceptable increase in life cycle costs. Therefore Lloyd's Register Rail has proposed to NedTrain to investigate the possibilities of improving the wheel tyre life. Three improvements were determined as most promising and relatively easy to achieve: - Profile optimisation for Rolling Contact Fatigue (RCF) reduction - a new wheel profile has been developed with a better resistance against rolling contact fatigue of the wheel tread. The profile has been implemented on single deck intercity trains and shows an increase in wheel tyre life of 30%. - Selection of improved wheel tyre materials - combining information from literature and experiences of manufacturers five alternative wheel tyre materials have been selected and are now being tested in practice. - Optimisation of the maintenance strategy - an alternative, preventative maintenance regime has been developed. With this Scraping regime, during short term maintenance every wheel is reprofiled. Higher mileages are reached and savings on life cycle costs up to 50% and more have been achieved. Unplanned maintenance goes down with $30{\sim}60%$. The results from field tests, using a reference group for comparison, and preliminary results after implementation show that the increase in wheel tyre life that is achieved with this project is significant. The results will continue to be monitored using the asset management tool 'Wheel Watch', that was specially developed for this project and is also described in this paper.

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Valve Analysis of Joystic steering System for Wheel Loader (휠로더 조이스틱 스티어링 시스템용 밸브 해석)

  • Ahn T.G.;Cheon T.H.;Kim Yong-Seok;Lim T.H.;Yang S.Y.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2006.05a
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    • pp.39-40
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    • 2006

  • The operation of wheel-loader is mainly divided into steering and excavating. The existing wheel-loader is used by handle for steering operation and by joystic for excavating operation. When we do steering and excavating operation simultaneously, we feel so uncomfortable because we have to use handle and joystic simultaneously. Therefore, we need to develop eletro-joystic steering system instead of hydraulic-handle steering system. So we can improve driving convenience in industrial field. This paper analyze spool of steering wheel and joystic and drive open area diagram. As a result, we can know characteristics of each valve before developing new electro-joystic steering system for wheel-loader.

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