• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.101-102
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• 2006

The purpose of this paper is pulsation-analysis of the swash plate type axial piston pump for excavator and the method of side branch hose application, which is used normally in construction equipments. In this paper, draw the mathematical modeling for pressure pulsation mechanism of the swash plate type axial piston pump for excavator, expression the flow pulsation in the pipelines by transfer matrix method, programmed simulation for pulsation by AMEsim software, and the reliability of that was verified by the comparison with the experimental results.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.7
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• pp.947-952
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• 2010

Components such as pressure vessel, hydraulic hose assembly, accumulator, hydraulic cylinder, hydraulic valve, pipe, etc., are tested under the impulse-pressure conditions prescribed in ISO and SAE standards. The impulse pressure test machine needs to have a high pressure, a precise control system and a long life. It should satisfy the requirements for fabrication of the impulse tester to generate ultra high pressure in the hydraulic system. In the impulse tester, a servo-valve control system is adopted; although the control application is convenient, it is expensive owing to the cost of developing the system. The type of the control system determines the pressure wave, which affects the components that are tested. In this study, the manufacturing process and the intensifier system design related to the flow, pressure, and the increasing rate of pressure are investigated. The results indicate the ultra high pressure waves in the system.

• Proceedings of the Korean Reliability Society Conference
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• 2011.06a
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• pp.281-288
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• 2011

Hydraulic hose assemblies deliver a fluid power in various oil pressure equipments such as construction machinery, automobile, aircraft, industrial machinery, machine tools, and machinery for ships, or they are used as pipes in oil pressure circuit. However, as the traditional measure for estimating life under the influence of various external factors incurs hardship in terms of time and expenses, it is essential to take accelerated life test by choosing the factor that suits the usage condition of the test object. The objective of the this study is to propose a acceleration model that takes both temperature and pressure without flexing condition into consideration. The life that is calculated by the equation for evaluating life and the test data show similar slopes as a result of comparing and analyzing the equation for evaluating life that is obtained in this research and the test data, which illustrates that they estimate life similarly, and the proposed equation is proved to be an accelerated life equation that presents the test results.

• Journal of Biosystems Engineering
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• v.33 no.6
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• pp.371-378
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• 2008

Bio-diesel applications seem to be extended due to bio-diesel policies and changes of agricultural environment. This study was conducted to develop a rapeseed reaping equipment attachable to the conventional combine. This paper was intended to report concept design, process and manufacturing of the prototype rapeseed reaping equipment. For concept design, physical properties of "SUNMANG", which is a typical rapeseed as bio-diesel materials, were considered. The designed prototype rapeseed reaping equipment consisted of wide-width plates, finger type knifes, side cutter knifes and drive equipments. The wide-width plate is 2.1 m wide, 0.7 m long, and 0.002 m thick. The finger type cutter knifes have 14.5 fingers, 30 knifes, and the specification was 7.6 cm of pitch, 8.3 cm of length and $21^{\circ}$ of cutting angle. The side cutter knifes consisted of a hydraulic pump, a hydraulic motor, a flow control and a relief valve, a hydraulic hose, a driving equipment and a reciprocating cutter knife. The 18 reciprocating cutter knifes were 137 cm long and knife pitch, knife length and cutting angle were 7.7 cm, 10.5 cm, and $18^{\circ}$. Prototype weight of the rapeseed reaping equipment was heavier by 272 kg when compared with the manual reaping equipments. Load distributions of left and right side showed 50% and 49%, and those of front and rear side showed 64% and 36%. Static turn-over angles in left and right of the prototype were $38.1^{\circ}$ and $38.7^{\circ}$, respectively. The designed prototype rapeseed reaping equipment was properly mounted at the front of a conventional combine.

• Journal of Power System Engineering
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• v.19 no.2
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• pp.15-21
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• 2015

Bollard installed on the street is a facility that protects pedestrians by restraining cars from entering on the sidewalk. It is basically classified into manual, semiautomatic, automatic type and mostly manual type is widely used because the automatic type is imported and much expensive. However, in case of manual handling type in practice, it is very troublesome and difficult to remove it whenever cars are permitted, and in case of automatic type, since underbody of a bollard is very long, it is difficult to dig a deep hole in the ground because a pipe, a hose or a cable is under the surface. In order to reduce these difficulties, this paper proposed new design of the multistage bollard that moves up and down automatically by using hydraulic system. This is developed by 6 step creativity of TRIZ inventive problem solving and structural analysis. The developed bollard can be installed in shallow hole and allow entry of vehicles through up-and-down movement without its removal manually. Finally, we could see smoothly motion through the manufactured bollard.

• 연구논문집
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• s.32
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• pp.35-43
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• 2002

This study was performed to develop accelerated life test method of machanical parts using cumulative damage theory that used to model the fatigue of parts that receive variable load. The cumulative damage theory was introduced, and the estimation of life and calculation of accelerated life test time was illustrated. As the actual application example, accelerated life test method of agricultural tractor transmission was described. Life distribution of agricultural tractor transmission was supposed to follow Weibull distribution and life test time was calculated under the conditions of average life (MTBF) 3,000 hours and 90% reliability for one test sample. According to the cumulative damage theory, because test time can shorten in case increase test load, test time could be reduced by 482 hours when we put the load 1.1 times of rated load than 0.73 times of rated load that is equivalent load calculated by load spectrum of the agricultural tractor. This time, acceleration coefficient was 11.7. This accelerated test method was used to develop accelerated test method of gear reducer, hydraulic hose and bearing as well as agricultural tractor transmission and it is considered to be applied comprehensively to machanical parts the fatigue of which is happened by load or pressure etc.

• Journal of Internet of Things and Convergence
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• v.9 no.2
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• pp.61-69
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• 2023

In recent years, due to heightened environmental awareness, Electric Power Steering (EPS) has been increasingly adopted as the steering control unit in manufactured vehicles. This has had numerous benefits, such as improved steering power, elimination of hydraulic hose leaks and reduced fuel consumption. However, for EPS systems to respond to actions, sensors must be employed; this means that the consistency of the sensor's linear variation is integral to the stability of the steering response. To ensure quality control, a reliable method for detecting defects and assessing linearity is required to assess the sensitivity of the EPS sensor to changes in the internal design characters. This paper proposes a data-driven defect and linearity assessment monitoring system, which can be used to analyze EPS component defects and linearity based on vehicle speed interval division. The approach is validated experimentally using data collected from an EPS test jig and is further enhanced by the inclusion of a Graphical User Interface (GUI). Based on the design, the developed system effectively performs defect detection with an accuracy of 0.99 percent and obtains a linearity assessment score at varying vehicle speeds.