• 한국자동차공학회논문집
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• 제2권4호
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• pp.59-71
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• 1994

A multi-polynomial method is proposed to synthesize DRRD cam profiles. A cam lift duration s divided into 10 sections, each of them is expressed by a polynomial equation. 12 design variables are extracted from the cam profile displacement, velocity, and acceleration curves. Because all the design variables have physical meanings which are familiar to most cam designers, it is easy to imagine a profile shape from the design variables. The design envelope of the method is wide enough to be used in DRRD automotive cam designs. Polydyne cams, widely used in automotive engines, are included into the envelope. Unlike Polydyne cams, the method provides capability of wide velocity factor variations, which gives much flexibility in flat-faced tappet design. Area factor of profiles designed by the method can be increased 5-10% compared to those of Polydyne cams without increasing acceleration factor. The method is especially useful for cam profile optimizations.

• 대한기계학회논문집
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• 제16권11호
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• pp.2049-2058
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• 1992

본 연구에서는 OHC형 캠-밸브 기구의 6자유도 집중 질량계 모델을 기본으로 하고, 밸브변위와 선회종동자(oscillating-follower or finger-follower)의 동적 스트 레인을 측정하여 모델의 타당성을 검증하고, 또 최적화 기법을 도입하여 밸브 개폐시 기, 밸브변위 그리고 최소 접촉력 등을 구속조건으로 주고 캠과 종동자 사이의 최대 접촉력을 최소화 시키도록 최적 캠 형상을 설계하였다. 그리고 설계된 캠을 정밀 가 공하여 최적화 설계의 타당성 및 접촉력을 실험을 통하여 검증하였다.

• 대한기계학회논문집
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• 제15권3호
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• pp.869-879
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• 1991

본 연구에서는 여러가지 평판 캠 기구에 대하여 효율적이며 정밀한 설계 및 가공을 할 수 있도록 CAD/CAM 소프트웨어를 개발하는데 목적이 있다. 즉, 주어진 캠 곡선과 캠 기구의 구성조건을 바탕으로 포락선 이론에 의하여 캠 형상을 구하고, 원하 는 가공 방법을 선정하여 황삭가공과 정삭가공에 대한 NC 파트프로그램을 얻는 기능들 을 하나의 통합된 CAD/CAM 소프트웨어로 구성하여 생산성과 효율성 및 정밀성 향상에 기여하고자 한다.

• 오토저널
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• 제9권1호
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• pp.15-22
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• 1987

내연기관의... 1. 실린더 내면의 윤활 1) 윤활유 소모율 2) 피스턴의 운전조건 3) 피스턴의 구조 2. 캠축의 윤활 1) 캠곡선의 형상 2) 캠의 재질

• 한국공작기계학회논문집
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• 제15권3호
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• pp.104-110
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• 2006

It is a study on the design of a cam profile for diesel engine SOHC. It is used a reverse engineering method without the usual copy processing. It draws up the contour data from an actual cam and processes by CNC. The profile of the cam is reappeared to be up to operational specifications that are the opening and shutting time, lift, speed and acceleration of the inhalation and escape valves. While the cam operating, the noise and vibration are occurred by the sudden change of speed. The new design of cam profile is suitable fur the valve operations to be smooth. We propose the design method of a cam profile far the reappearance of an actual cam. It is proved to be the propriety about the design of the cam profile through the processing, measurement, and comparison of the cam profile.

• 대한기계학회논문집
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• 제17권6호
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• pp.1361-1371
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• 1993

본 연구에서는 여러가지 입체 캠 기구에 대하여 기구학적인 구성조건과 캠 곡선을 바탕으로 매개변수형태의 포락면이론에 의하여 캠 형상을 구하고, 이를 직접 가공할 수 있는 NC 파트프로그램을 얻는 CAD/CAM 소프트웨어를 구성하여 정밀성, 생산성, 효율성 등을 증진하고자 한다.

• 한국자동차공학회논문집
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• 제6권4호
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• pp.129-140
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• 1998

A numerical method is proposed to optimize automotive cam profiles. An acceleration curve of a cam follower motion is described by Hermite spline curves. Because of the intrinsic characteristics of the Hermite curve, it is possible to design an acceleration curve with arbitrary shape. Design variables in the optimization problem are location of control points which define the acceleration curve. Objective function includes dynamic performances as well as kinematic properties of a valve train. Similar optimization procedure was also performed using Polydyne cam profile synthesis method. Optimized profiles using the Hermite curve are proved to be superior to those using the Polydyne method.

• 한국자동차공학회논문집
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• 제4권1호
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• pp.110-122
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• 1996

The objective of this study is to understand the dynamic characterictics of OHV type valve trains and to design and optimal cam profile which will improve engine performance. A numerical model for valve train dynamics is presented, which aims at both accuracy and computational efficiency. The lumped mass model and distributed parameter model were used to describe the valve train dynamics. Nonlinear characterictics in the valve spring behavior were included in the model. Comprehensive experiments were carried out concerning the valve train dynamics, and the model was tuned based on the test results. The dynamic model was used in designing an optimal cam profile. Because the objective function has many local minima, a conventional local optimizer cannot be used to find an optimal solution. A modified adaptive random search method is successfully employed to solve the problem. Cam lobe area could be increased up to 7.3% without any penalties in kinematic and dynamic behaviors of the valve train.

• 한국자동차공학회논문집
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• 제3권5호
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• pp.90-99
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• 1995

A numerical method is proposed to synthesize automotive cam profiles. An arbitrary acceleration profile for the cam follower motion is divided into several segments, each of them is described by a Hermite curve. A cam profile is defined by control point locations and control variables assigned to each segment. Closed form equations are derived for velocity and displacement constraints which should be satisfied for the curve to be a cam profile. Because the method is flexible and provide arbitrary local controllability, any types of cam acceleration profile can be reproduced by the method. The method is expecially useful for the design of roller type OHC valve trains which need precise local control in the cam profile design to avoid under-cutting problems.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 추계학술대회 논문요약집
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• pp.225-225
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• 2003