피스톤 헤드의 형상에 따른 열응력 해석에 관한 융합 연구

오범석,조재웅 한국융합학회 2020 한국융합학회논문지 Vol.11 No.7

In this study, thermal stress analysis by shape of piston head was conducted to investigate the shape of a durable piston. As the result, the farther the temperature is from the part where the temperature is applied, the lower the temperature can be seen. Depending on the shape of the piston head, the heated area became different. So, it could be seen that it affected the piston column part and the skirt part. This study showed that three models produced the least stress from the center of the piston head in the same way. Model A showed the smallest stress resulting in the yield compared to the other two models. Model B is a plate type piston head with a concave shape of the piston head, indicating that it is the model that has the least effect on the surrounding area at the center of the piston head. Model C showed the greatest stress resulting from the yield. The results of this study are also thought to be useful for designing the shape of durable pistons. By utilizing the thermal stress analysis due to piston head shape, this study is thought to conform with the aesthetic design. 본 연구에서는 피스톤 헤드의 형상별 열응력해석을 진행하여 내구성이 있는 피스톤의 형상을 고찰하기 위한 연구를 진행하였다. 그 결과로서는 온도가 가해지는 부분에서부터 거리가 멀수록 낮은 온도를 볼 수 있다. 피스톤 헤드의 형상에 따라 열을 받는 면적이 다르기 때문에 피스톤 기둥 부분과 스커트부에 영향을 끼치게 된 점을 볼 수 있었다. 본 연구에서는 세 모델이 동일하게 피스톤 헤드의 중심부에서 가장 적은 응력이 나오는 것을 알 수 있었다. Model A는 다른 두 모델에 비해 항복이 발생하는 응력이 가장 작은 것을 알 수 있었다. Model B는 접시형 피스톤헤드로서 피스톤 헤드부가 오목한 형상으로 되어 있어 피스톤 헤드 중심부에서는 주변 부분에 영향을 가장 덜 끼치는 모델임을 알 수 있었다. Model C는 항복이 발생하게 되는 응력이 가장 크게 보였다. 또한 본 연구결과는 내구성이 있는 피스톤의 형상 설계에 유용하게 적용할 수 있다고 사료된다. 피스톤 헤드의 형상에 따른 열응력 해석을 적용함으로서, 본 연구가 미적인 융합에 부합된다고 사료된다.

사축식 피스톤 펌프의 피스톤 링과 실린더 보어간의 윤활특성에 관한 연구

정재연(JaeYoun Jung),조인성(IhnSung Cho),백일현(IlHyun Baek),손소화(ShaoHua Sun),신현일(Hyunil Shin),송규근(KyuKeun song),오석형(SeokHyung Oh) 한국트라이볼로지학회 2007 한국트라이볼로지학회 학술대회 Vol.2007 No.6

The bent-axis type piston pump which is driven by the piston rod works on the way that the piston rod drives the cylinder block, so the taper angle of the piston rod and the swivel angle between the cylinder block and the shaft are very important design factors. If the above factors cannot satisfy the conditions of optimum design, the friction loss between the cylinder bore and the piston increases, and the pump can even fail to work under conditions of severe friction and wear. Since the piston reciprocates in the cylinder bore with high velocity, and at the same time it rotates on its own axis and revolves on the center of the cylinder block, the decrease of the volume efficiency generated on account of the leakage between the cylinder bore and the piston. Therefore, to prevent this case, the piston ring is designed at the end of the piston, and the friction characteristics between the piston ring and the cylinder bore are in need of research due to its great influence on the performance of piston pump. Thus, in this paper, the elastic hydraulic oil’s lubrication analyses of the film thickness, the pressure distribution, and the friction force, and so on, have been performed, and the lubrication characteristics between the piston ring and the cylinder bore are explored by the results of the numerical analysis, and it is contributed to realize the higher efficiency and the more advanced performance of the bent-axis type piston pump.

레이디얼 피스톤 펌프의 피스톤 접촉 메커니즘 개발

함영복,차재곤,김대명,공태우,윤소남,안국영,권병수 사단법인 유공압건설기계학회 2010 드라이브·컨트롤 Vol.7 No.1

This paper presents the experimental results of the radial piston type oil pump with new mechanism for a metal diaphragm hydrogen compressor. Generally, metal diaphragm type hydrogen compressor systems are operated by oil hydraulic power. In this system an oil compensating pump has been demanded to compensate for a leakage oil head chamber. The metal diaphragm type hydrogen compressor consists of an oil compensating pump, commonly used hydraulic piston pump and driven by main crank shaft. The radial piston type oil compensating pump with new rolling contacted piston mechanism is developed and experimented. The developed piston element of the radial piston pump consists of piston, steel ball, return spring, two check valves, eccentric cam and ball racer. In this study, designed 4 type pistons as and orifice hole. Operating characteristics and pressure ripple characteristics are tested under no load to 60bar loaded with every 20bar increasing step and pressure ripple and flow rate are experimentally investigated. 수소압축기는 무급유 방식의 왕복동식과 무윤활 방식의 메탈 다이아프램 방식으로 양분되며, 각 방식에 따라 수소의 순도와 충진압에서 일장일단의 특성을 나타낸다. 메탈 다이아프램 수소압축기는 유압구동부의 누설유량과 흡입 시 발생하는 캐비테이션 방지를 위한 과급유 상태를 유지할 수 있도록, 피스톤 챔버와 오일 헤드 챔버에 오일을 보충하게 된다. 이러한 목적으로 오일보충용 펌프는 압축기의 크랭크케이스 내부의 메인 크랭크샤프트에 연결하여 구동하게 된다. 본 연구에서는 메탈 다이아프램 수소압축기의 오일 보충용 펌프로 개발된 레이디얼 피스톤 펌프의 피스톤을 스틸 볼이 볼 레이스 위를 구름 접촉하도록 구성하고 볼이 설치된 피스톤 끝면 윤활용 오리피스를 설치하고 서로 다른 오리피스 직경에 대해 실험적으로 비교 평가하고 개발된 펌핑 메카니즘의 구조적 타당성을 검토해 본다.

냉각 갤러리 형상이 디젤엔진 피스톤 온도에 미치는 영향

김충희(Chunghui Kim),신윤섭(Yunsub Sin),이기수(Geesoo Lee),김현철(Hyunchul Kim),유연설(Younsul Yoo),김희수(Heesu Kim) 한국자동차공학회 2013 한국자동차공학회 부문종합 학술대회 Vol.2013 No.5

The weakest point in the piston of the engine is a piston bowl edge where mechanical and thermal loads are directly transferred. One of the promising technologies to complement this issue is remelting piston crown, which increases the durability and strength of the piston. In this study, experimental study was carried out with three types of pistons (base piston, re-melting piston, and down gallery piston). Piston surface temperature was measured for the purpose of . Numerical analysis using FEM was then conducted to evaluate the experimental results. It was revealed that re-melting piston can apply to the conventional diesel engine since the piston temperature from a re-melting piston applied engine was almost the same with that from base piston engine without sacrifice of power and torque.

차량용 사축식 피스톤 펌프의 피스톤 링과 실린더 보어간의 윤활특성에 관한 연구

정재연(JaeYoun Jung),조인성(IhnSung Cho),송규근(KyuKeun Song),백일현(IIHyun Baek),오석형(SeokHyung Oh),정석훈(SeokHoon Jung),정용욱(YongWook Jeong) 한국트라이볼로지학회 2007 한국윤활학회지(윤활학회지) Vol.23 No.5

The bent-axis type piston pump which is driven by the piston rod works on the way that the piston rod drives the cylinder block, so the taper angle of the piston rod and the swivel angle between the cylinder block and the shaft are very important design factors. If the above factors cannot satisfy the conditions of optimum design, the friction loss between the cylinder bore and the piston increases, and the pump can even fail to work under conditions of severe friction and wear. Since the piston reciprocates in the cylinder bore with high velocity, and at the same time it rotates on its own axis and revolves on the center of the cylinder block, the decrease of the volume efficiency generated on account of the leakage between the cylinder bore and the piston. Therefore, to prevent this case, the piston ring is designed at the end of the piston, and the friction characteristics between the piston ring and the cylinder bore are in need of research due to its great influence on the performance of piston pump. Thus, in this paper, the elastic hydraulic oil's lubrication analyses of the film thickness, the pressure distribution, and the friction force, and so on, have been performed, and the lubrication characteristics between the piston ring and the cylinder bore are explored by the results of the numerical analysis, and it is contributed to realize the higher efficiency and the more advanced performance of the bent-axis type piston pump.

가솔린엔진에서의 피스톤 슬랩 소음 저감을 위한 실험적 연구

이홍욱(Hong Wook Lee),이상원(Sang Won Lee),조진우(Jin Woo Cho),김중수(Joong Soo Kim),이상희(Sang Hee Lee),김우태(Woo Tae Kim) 한국자동차공학회 2006 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-

Piston slap noise is one of the most significant mechanical noise sources in an internal combustion engine. It is a dynamic impact phenomenon between the piston and the cylinder block caused by changes in the lateral forces acting on the piston. In this paper, the optimization of piston design parameters using robust design method is carried out to minimize piston slap noise. Orthogonal arrays of L? and dynamic characteristic are used to conduct test and to analyze experimental data, respectively. Experimental results show that piston slap is strongly affected by skirt shape and compression height as well as by pin offset. Therefore, optimization of piston design parameters can lead drastically reduced piston slap vibration.

피스톤의 점성 마찰력을 고려한 소형 왕복동 압축기의 동적 해석

김태종 한국소음진동공학회 2002 한국소음진동공학회 논문집 Vol.12 No.11

In this study, a dynamic analysis of the reciprocating compression mechanism considering viscous friction force of a piston used in small refrigeration compressors is performed. The length of cylinder in this class of compressors is shortening to diminish the frictional losses of the piston-cylinder system. So, the contacting length between piston and cylinder liner is in variable with the rotating crank angle around the BDC of the reciprocating piston. In the problem formulation of the compression mechanism dynamics, the change in bearing length of the piston and all corresponding viscous forces and moments are considered in order to determine the trajectories of piston and crankshaft. The piston orbits for viscous friction model and Coulomb friction model were used to compare the effect of the friction forces of piston on the dynamic trajectories of piston. To investigate the effect of friction force acting on the piston for the dynamic characteristics of crankshaft, comparison of the crankshaft loci is given in both viscous model and Coulomb model. Results show that the viscous friction force of piston must be considered in calculating for the accurate dynamic characteristics of the reciprocating compression mechanism.

사축식 피스톤 펌프에서 2중 피스톤 링의 윤활 특성

정재연(JaeYoun Jung),조인성(IhnSung Cho),백일현(IlHyun Beak),조재천(JaeCheon Jo),송규근(KyuKeun Song),오석형(SeokHyung Oh) 한국트라이볼로지학회 2009 한국트라이볼로지학회 학술대회 Vol.2009 No.6

The bent-axis type piston pump which is driven by the piston rod works on the way that the piston rod drives the cylinder block, so the taper angle of the piston rod and the swivel angle between the cylinder block and the shaft are very Important design factors. If the above factors can not satisfy the conditions of optimum design, the friction loss between the cylinder bore and the piston increases, and the pump can even fail to work under conditions of severe friction and wear. Since the piston reciprocates in the cylinder bore with high velocity, and at the same time it rotates on its own axis and revolves on the center of the cylinder block, the decrease of the volume efficiency generated on account of the leakage between the cylinder bore and the piston. Therefore, to prevent this case, the piston ring is designed at the end of the piston, and the friction characteristics between the piston ring and the cylinder bore are in need of research due to its great influence on the performance of piston pump. Thus, in this paper, the elastohydrodynamic lubrication(EHL) analysis of the film thickness, the pressure distribution and the friction force, have been studied between the piston ring and the cylinder bore in the bent-axis type piston pump. The analyzed results show that friction force is influenced by rotating speed and discharge pressure.

사축식 피스톤 펌프의 피스톤 링과 실린더 블록 사이의 윤활 해석

정재연(JaeYoun Jung),조인성(IhnSung Cho),백일현(IlHyun Beak),신현일(HyunIl Shin),송규근(KyuKeun Song),오석형(SeokHyung Oh),장동혁(DongHyuk Jang) 한국트라이볼로지학회 2008 한국트라이볼로지학회 학술대회 Vol.2008 No.11

The bent-axis type piston pump which is driven by the piston rod works on the way that the piston rod drives the cylinder block, so the taper angle of the piston rod and the swivel angle between the cylinder block and the shaft are very important design factors. If the above factors can not satisfy the conditions of optimum design, the friction loss between the cylinder bore and the piston increases, and the pump can even fail to work under conditions of severe friction and wear. Since the piston reciprocates in the cylinder bore with high velocity, and at the same time it rotates on its own axis and revolves on the center of the cylinder block, the decrease of the volume efficiency generated on account of the leakage between the cylinder bore and the piston. Therefore, to prevent this case, the piston ring is designed at the end of the piston, and the friction characteristics between the piston ring and the cylinder bore are in need of research due to its great influence on the performance of piston pump. Thus, in this paper, the elastohydrodynamic lubrication(EHL) analysis of the film thickness, the pressure distribution and the friction force, have been studied between the piston ring and the cylinder bore in the bent-axis type piston pump. The analyzed results show that friction force is influenced by rotating speed and discharge pressure.

엔진 파이어링동안 일정 축 각속도에서 비고정식 피스톤-핀과 연결봉-소단부 부싱 및 피스톤-핀 보스의 접촉면 마모해석

전상명 한국트라이볼로지학회 2020 한국트라이볼로지학회지 (Tribol. Lubr.) Vol.36 No.3

In recently designed diesel engines, the running conditions for piston-pin bearings have become severe because of the higher combustion pressure and increased temperature. Moreover, the metal removal from the bushing material has strongly reduced the ability of the antifriction material to accept asperity contacts. Therefore, it is necessary to find ways of reducing wear scar on the connecting-rod small-end bushing and piston-pin boss bearing related to the higher combustion pressure on the power cell of an engine. In this work, the position and level of material removal from the surfaces of the bushing and bearing under such severe operating conditions - for example, maximum power and torque conditions of a passenger car diesel engine - are estimated for several combinations of surface roughness. First, piston-pin rotating motion is investigated by calculating the friction coefficient at piston-pin bearings, the oil film thickness, and the frictional torques induced by hydrodynamic shear stress. Subsequently, the wear scarring on the surfaces of a connecting-rod small-end bushing and two piston-pin boss bearings related to piston-pin rotational motion is numerically calculated under the maximum power and torque operating conditions. This work is helpful to determine the reasonable surface roughness of the bushing and bearing for reducing wear volume occurring at the interface between a bearing and a shaft.