• 한국정밀공학회지
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• 제30권7호
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• pp.679-686
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• 2013

The reduction unit is one of the most important components in railway cars, due to the transmission of torque from the motor to the wheels. Faulty reduction gears in high-speed trains result from excessive wear on the gear or damage to the gear. These types of gear defects have a significant effect on high-speed rail operation and safety; thus, a diagnosis system for the reduction unit is needed. Vibration diagnosis technology is one of the most effective diagnostics. In this paper, the vibration parameters of a reduction unit were evaluated during a driving-gear test and a full-vehicle test, using kurtosis and the crest factor. These tests were performed under normal operating conditions; a specimen tester was used to diagnose problems in defective gears.

• 유공압시스템학회논문집
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• 제6권1호
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• pp.10-16
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• 2009

Automatic power transmission systems consisted of a torque converter and several planetary gear sets, clutches and brakes are controlled by a hydraulic shift control circuit and an electronic transmission control unit. The hydraulic circuit serves for the operation of the torque converter and lubrication oil supply of the transmission system as well as for the actuation of clutches for the automatic gear shift. The complicated hydraulic control circuit constructed by many spools, solenoids, orifices and flow passages are integrated into one small valve block and it is powered by one hydraulic pump. In this paper, a test equipment was developed to measure the oil consumption of each component at various wide operating conditions. Test data about 730 sets acquired from five test items are analyzed and discussed on the oil capacity of the circuit.

• 한국가스학회지
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• 제19권3호
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• pp.49-53
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• 2015

이 논문의 목적은 자동차 클러치, 수동변속기와 타이어 시스템의 마찰에 관련된 화재에 대한 고장사례를 분석하고 연구하는 것이다. 첫 번째 사례는 반복적으로 클러칭하면서 자동차의 클러치 디스크가 플라이 휠의 접촉면과 접촉하면서 열에 의해 과열되어 이 열이 수동변속기의 외부로 흘러 고착된 오일 찌꺼기에 옮겨 붙어 화재가 발생된 것으로 확인되었다. 두 번째, 사례로 변속 장치는 기어와 기어의 접촉에 의해 동력을 전달한다. 변속기 오일이 변속기 케이스의 균열로 인해 오일 부족 현상이 일어나 변속기 케이스 상단의 퇴적물에 의해 화재가 발생된 것을 확인하였다. 세번째 사례는 건조한 구덩이에서 빠져나오려고 반복적으로 가속페달을 작동시키면서 타이어와 도로의 마찰이 반복되면서 내부의 축적된 열에 의해서 화재가 발생된 것으로 확인되었다. 따라서, 운전자는 운전 중 마찰부에 화재가 발생하지 않도록 세심하게 관리하여야 한다.

• 한국소음진동공학회논문집
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• 제24권1호
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• pp.54-61
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• 2014

This paper proposes a driver supportive device with haptic cue function which can transmit optimal gear shifting timing to a driver without requiring the driver's visual attention. Its performance is evaluated under vehicle model considering automotive engine, transmission and vehicle body. In order to achieve this goal, a torque feedback device is devised and manufactured by adopting the MR (magnetorheological) fluid and clutch mechanism. The manufactured MR clutch is then integrated with the accelerator pedal to construct the proposed haptic cue device. A virtual vehicle emulating a four-cylinder four-stroke engine, manual transmission system of a passenger vehicle and vehicle body is constructed and communicated with the manufactured haptic cue device. Control performances including torque tracking and fuel efficiency are experimentally evaluated via a simple feed-forward control algorithm.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.899-904
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• 2003

Tight integration of product design and process planning in the early design stage would make bigger impact as wider spectrum of design and manufacturing alternatives can be pursued and evaluated. Thus the development of systematic computer-based support for this integration is desirable. For this integration and process planning in the early design stage. the systematic method to synthesize shape of part from functional requirements is crucial. This research presents the methods of functional decomposition from overall function or product and synthesizing shape of part based on functional relations extracted from functional decomposition using planetary gear transmission system as an example.

• 한국자동차공학회논문집
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• 제2권5호
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• pp.110-120
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• 1994

Due to the increasing demands in comfortable drivability, most motor companies are developing their own unique shift controller to suppress the shift shock induced by gear change. For a typical automatic transmission system, the dynamic constraints of friction clutch was clarified for efficient program development and major factors effecting the shift transient was confirmed by simulation study. The MIMO LQG/LTR controller was designed to control the turbine and corresponding gear speed. By establishing the control strategy recalling transient response during shift the speed controller mentioned above was used as an indirect torque controller. Consequently a new concept for a systematic design method of shift controller applicable to wide-varying systems was suggested which is time efficient and cost efficient saving a lot of experimental study.

• 한국정밀공학회지
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• 제21권11호
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• pp.140-148
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• 2004

Tight integration of product design and process planning in the early design stage would make bigger impact as wider spectrum of design and manufacturing alternatives can be pursued and evaluated. Thus the development of systematic computer-based supporting for this integration if desirable. For this integration and process planning in the early design stage, the systematic method to synthesize shape of part from functional requirements is crucial. This research presents the methods of functional decomposition from overall function of product and synthesizing shape of part based on functional relations extracted from functional decomposition using planetary gear transmission system as an example.

• 한국자동차공학회논문집
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• 제17권1호
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• pp.19-23
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• 2009

This paper focuses on vehicle fuel economy improvement using D-Range neutral control of automatic transmission. The system objected to reducing of fuel consumption during idle. Usually, turbine of conventional auto transmission is mechanically linked to wheel during idling condition. Therefore speed ratio of torque converter is zero for that period. This causes needless power loss by the torque converter slip. To improve this inefficiency automobile makers develops electronically-controlled D-range neutral control system. The D-range neutral control system minimizes slip on the torque converter by shifting gear to a neutral position during vehicle stoped with D-range gear position. However there's insufficient study about the effect of D-range neutral control system on vehicle fuel economy. In this paper, researches are performed on effect of D-range neutral control system on vehicle fuel economy by experiment with two different vehicle. And it is also estimated the effect on vehicle fuel economy using computer simulation. As a result, 1.8% of LA-4 mode fuel economy improvement can be achieved in a vehicle by D-range neutral control system.

• 대한기계학회논문집
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• 제18권12호
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• pp.3246-3252
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• 1994

The vibration of meshing gear system is originated form teeth deformation, teeth contact ratio, profile error, etc. The gear vibration is classified as whine vibration during meshing and as rattle vibration during idling. In this study, the whine vibration is investigated under the assumption of piecewise linearity of elastic stiffness due to the variation of meshing. Numerical, theoretical and experimental investigations show the existence of the superharmonic components of the second and the third order. consistently It can be concluded that the superharmonic components in whine vibration of meshing gear is originated from the stiffness variation. It also shows that the higher order harmonics are reduced on the increase of motor speed.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 1993년도 Proceedings of International Conference for Agricultural Machinery and Process Engineering
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• pp.1102-1109
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• 1993

This paper describes the research and development of Walking Tractors and Tillage Implements for Phase I (1991-1992) . The project consists of : (1) the study and need for the development of the walking tractors for Thailand and other Southeast Asian countries ; (2) the comparison in the use of the walking tractors and their transmission systems that are made in Thailand and aborad : and (3) the design of future walking tractors for Asian farmers in developing countries. The design of the walking tractors is concentrated to provide the ease to farmers, especially the elderly and female which will play an important role in the future agriculture of Thailand due to the lack of manpower. In addition , the design of the walking tractors is also aiming for small-scale farmers, the majority that have limited land capital. The walking tractors consist of several components but the most important one is the " Transmission System" . Thus, the research is concentrated in the devel pment an design of the a new transmission system. The new machine , currently developed, is named after the Chulalongkron University as " Chular Walking Tractor " , model SPJS -60. The tractor uses a 6-7 horsepower diesel engine with three forward gears and one reverse gear. The tractor also uses the latest gearing technology so called planetary gearing system with steering clutches system that never been used in any earlier model. The advantages of the planetary gearing system are : (1) the final drive gear can be small, and can be designed to provide higher strength with less wearing resistance, (2) the system eliminates a shaft which is used in other systems, thus reduces the weight and the manufacturing cost . Furthermore, the Chular Walking Tractor has an additional power take off shaft that can be used or linked with other standard agricultural implements.