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송창헌(C. H. Song),신대영(D. Y. Shin) 유공압건설기계학회 2010 유공압건설기계학회 학술대회논문집 Vol.2010 No.10
This study focuses on interaction and compatibility between hydraulic oil and Seal. These interactions are carried out by experiments based on Korean Industrial Standard. The mineral hydraulic oil and synthetic hydraulic oil based on HEES(Hydraulic Environmental Ester Synthetic) were used in the experiments. Specimen is NBR and polymer plastic that material for low friction seal. Design factors are time, temperature and moisture content rate. In addition, it analyzed variations of characteristics of hydraulic oil and Seal. For example, characteristics of hydraulic oil are viscosity and TAN and those of Seal are tensil strength and elongation. The experiemtn results are as follows Hydraulic oil and polymer plastic were showing positive characteristic changes, whereas NBR was not.
권기범(K. B Kwon),송창헌(C. H. Song),이재욱(J. W. Lee),박진영(J. Y. Park),오주영(J. Y. Oh),조정우(J. W. Cho) 유공압건설기계학회 2013 유공압건설기계학회 학술대회논문집 Vol.2013 No.6
A drill bit, which directly impact into the rock, is operated by percussive force and torque. In order to increase the drilling efficiency, the buttons on drill bit head should be designed under the optimum arrangements. Thus, the drilling efficiency should be investigated. In this study, percussion tests were carried out to assess the fragmentation performance of a drill bit. To investigate the drilling efficiency with testing conditions (i.e., blow speed and spacing), single and multiple piston-drop tests were performed on the granitic rock in Korea. After the tests, the drilled volumes of rock were measured by laser scanner. The drilling efficiency was eventually evaluated by calculating the percussive energy and the drilled volume.