• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.373-374
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• 2013

• Tribology and Lubricants
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• v.33 no.2
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• pp.71-78
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• 2017

The drag torque in the wet clutch system of a dual clutch transmission system is investigated because it is relatively high, up to 10 of the total output torque of the engine, even when the clutch is in the disengagement state with zero torque transfer. Drag torque results from the shear resistance of the DCTF between the friction pad and separator plate. To reduce the drag torque for ensuring fuel economy, the groove pattern of the wet clutch friction pad is designed to have a high flow rate through the pattern groove. In this study, four types of groove patterns on the friction pad are designed. The volume fraction of the DCTF (VOF) and hydrodynamic pressure developments in the gap between the friction pad and separator plate are computed to correlate with the computation of the drag torque. From the computational results, it is found that a high VOF and hydrodynamics increase the drag torque resulting from the shear resistance of the DCTF. Therefore, a patterned groove design should be used for increasing the flow rate to have more air parts in the gap to reduce the drag torque. In this study, ANSYS FLUENT is used to solve the flow analysis.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.5
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• pp.778-783
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• 2012

Due to the increase of oil price, the needs of the reduction of the fuel cost is rising. Therefore, necessity of hybrid vehicle that runs with engine and the electric motor is on the rise. In order to improve the performance of hybrid vehicle, many researches is carried out. Hybrid vehicles have been developed with the various layout such as serial type, parallel type, power split type, and multi-mode type. The multi-mode hybrid vehicles are designed to show the efficient driving characteristics at low speed and high speed. But the multi-mode system have the problem such as frequent clutch engagement. Frequent clutch engagement causes the shock of vehicles, and the shock inhibits the ride comfort. In this study, automation mechanism of clutch operation is proposed to mitigate the shock at engaging clutch. For this purpose, the dynamic characteristics of motor control is numerically analyzed by using Matlab/Simulink.

• IE interfaces
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• v.14 no.2
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• pp.134-139
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• 2001

This paper describes an automatic design system for the parts that compose the power transmission. Power transmission is composed of shaft, gear, clutch, brake and housing. To design power transmission, there are many recurrent calculations and drawings needed with conventional design process. In this paper, we propose three dimensional automatic design system that reduce recurrent calculations and drawings. Developed system consists of two modules; 1) Design expert system module to assist determining design parameters of clutch, brake and gear. 2) Parametric modeling module to make three dimensional solid model automatically. The proposed system has been tested in the fields and found to be a useful system.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.36 no.3
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• pp.1-7
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• 2013

This paper is a case study of reliability assessment with field warranty data of Clutch Master Cylinder (CMC) in hydraulic clutch system. We estimate lifetime distribution using field warranty data which contain much useful information for understanding reliability of the system in the real-world environments. However, the estimated parameters are far from existing reference values, which seems to be caused right censored field warranty data. To modify the parameters, we use the information of the durability test which is performed to verify that the lifetime of the item meets the required level. After that, we can observe that the modified parameters are closer to the existing reference values. This case study shows a possible idea to supplement lack of right censored field warranty data and its applicability.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.3
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• pp.56-62
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• 2022

The tank engine clutch flange constitutes a tank on which the engine and transmission of the tank are mounted. The engine clutch flange is fabricated using a difficult-to-cut material that exhibits high strength and hardness. It is difficult to process and requires considerable processing expertise. In addition, the engine clutch flange for the tank requires high machining precision because it is a system in which the connection is detachable. Because it requires high processing precision, the measurement of products equally important as processing. However, productivity is low owing to the significant amount of time required to measure each product using a three-dimensional coordinate measuring machine. Hence, this study is conducted to improve the productivity of the female tank engine clutch flange. Dedicated hobs and jigs are designed and manufactured to convert the existing end-mill cutting processing into hobbing cutting processing. An engine clutch for the tanks is manufactured using the manufactured dedicated hob and jig, and the shortening time is verified by measuring the processing time. In addition, a jig for inspection is designed and manufactured to measure the precision of the product. To verify the inspected product, the product precision is measured using a contact-type three-dimensional coordinate measuring machine and a surface roughness measuring instrument. The study confirmed that the productivity of the engine clutch flange product for tanks can be improved by simplifying the process, reducing the processing time, and simplifying product inspection.

• Journal of the Korean Society for Precision Engineering
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• v.24 no.10
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• pp.75-82
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• 2007

The AMT(Automated Manual Transmission) has been developed by utilizing the auto clutch system and the automatic shift mechanism, to automate the clutch operation and shift operation of the existing MT(Manual Transmission). The use of hydraulic actuator for each actuator of the clutch and gear has realized a reduction of fuel consumption and exhaust emission. In this paper, we develop a simulator for the transmission control system of the AMT using AMESim. The developed simulator can be applied to design the hydraulic select actuator system of an AMT.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.1572-1577
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• 2003

The powershift transmission have the advantage of easier operation and higher efficiency by using the hydraulic clutch and mechanical power transfer system. It is important to control the engaging pressure and time. The hydraulic control system is used for these controls of the modulator valve, the accumulator, the sump valve and etc. This study have made a simulator for verifying the pressure characteristic of the shuttle powershift transmission and developed the computer simulation model of the hydraulic components and system by using 'AMESim'. As a result, the design parameters which have an effect on the pressure modulation are verified to the spring stiffness of the modulator valve and the volume of the accumulator.

• Journal of Power System Engineering
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• v.17 no.5
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• pp.128-137
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• 2013

Modern transmission technologies such as automated manual transmission(AMT) and dual clutch transmission(DCT) are interested to all manufactures due to their fuel efficiency and driver's convenience, especially in a hybrid system. AMT has advantages in that they have a high efficiency of manual transmissions(MT) and offer operation convenience similar to automatic transmissions(AT), but it has some disadvantages in that they have torque gap during gear shift and shift time. To reduce disadvantages, it is necessary to evaluate errors and characteristics as a developing simulation model before experimental verification. The purpose of this study is to develop virtual components and simulate the transient response of AMT. A dynamic AMT model and a control logic for an integrated vehicle model have been developed using Matlab/Simulink as a simulation platform. In this paper, the clutch model to describe the stick-slip transition mode and the transmission model to describe the neutral gear shifting is introduced and compared with each other.

• Journal of Mechanical Science and Technology
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• v.17 no.4
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• pp.521-527
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• 2003

Modern automatic transmissions equip torque converters with lock-up clutches to reduce the energy loss of hydraulic systems. Instead of simply engaging the clutch disks, the new technology of clutch slip has been developed to improve the overall efficiency of power transmission. There are two major problems with the clutch slip system. The first is how to keep the slip between the two disks within a small range and the second is when to start or stop the slip. In this paper, the second problem is discussed in view of the vehicle economy. With a simple vehicle dynamic model, the fuel economy is calculated to determine the lock-up strategy. Then the lock-up strategy is developed for a slip schedule.