• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.291-294
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• 2005

This paper presents a method of improving performance of an electromagnetic clutch for the next generation tank gun. One of the most important things in the design of the clutch is to satisfy the requirement for the maximum torque even if the torque is varied. To achieve this requirement, it is needed to expand the operation range of the torque. Consequently, we have performed shape changes in order to cancel magnetic flux bottlenecks on the magnetic path. Simulation results from the finite element method show that the method proposed in this paper is proper for the clutch.

• Tribology and Lubricants
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• v.25 no.4
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• pp.243-249
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• 2009

A magnetic clutch consists of pulley and disk. It delivers and isolates the power needed for the operation of the compressor used in automotive air conditioning system. To improve the performance, efficiency and durability of automotive air conditioning system, appropriate design of pulley, disk and system working parameters(the magnitude of magnetic force, and so on) is necessary. For that goal, it is required to understand the friction characteristics of magnetic clutch for the initial operating time. In this study, friction tests were carried out in order to investigate the effect of sliding velocity on the friction characteristics of magnetic clutch using pin-on-disk type friction and wear tester. For experiments, pulley and disk used in real automotive air conditioning system were considered. Friction experiments were conducted under various sliding velocities, and coefficients of kinetic friction were obtained. Under the experimental conditions considered in this study, the coefficients of kinetic friction increased with the increase of test number(sliding distance) and decreased with the increase of sliding velocity.

• Transactions of the Korean Society of Automotive Engineers
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• v.20 no.5
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• pp.65-70
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• 2012

Torque fluctuation of engine generate gear rattle noise of transmission and many researches have been studied to decrease rattle noise by adjusting clutch damper system. So design optimization of clutch system is very important to decrease rattle noise and need knowing clutch dynamic torque at real vehicle driving condition. This makes it possible to measure clutch dynamic torque by using a small-size magnetic sensor. We install a small-size magnetic sensor on the input shaft of the transmission and measure the relative angular displacement between clutch hub and disc plate. We can obtain the clutch torque correspond to the angular displacement in the clutch torsional characteristics test. The object of this research is to measure clutch dynamic torque on real vehicle condition. Therefore, Clutch dynamic torque is very useful for investigating operating range of clutch according to engine torque and predicting the damping performance of torsional vibration on the powertrain.

• Transactions of the Korean Society of Automotive Engineers
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• v.17 no.3
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• pp.22-28
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• 2009

Recently, there has been an active study about smart fluid to control the vibration, in which MR fluid is evaluated as most efficient because it can generate different bonding forces based on the intensity of the external magnetic fields. This paper attempts to find a mechanism that, under limited conditions during a clutch production that uses such dynamic characteristic, defects the maximum intensity of electromagnetism. Using the finite element analysis program, we predicted a change within the bonding force of the MR fluid occurring inside the clutch when it is subjected to an increased electric current. In addition, we analyzed the change in the magnetic intensity when the coil comprising the coil control center is switched to multiple lines from the standard single line, to find a mechanism that can maximize the effect. Based on this analysis, we developed the clutch and tested its function, hoping to widen future MR fluid's range of application.

• Transactions of the Korean Society of Automotive Engineers
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• v.1 no.1
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• pp.101-109
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• 1993

Dynamic characteristics of an electro-magnetic clutch transmission system were investigated by using Bondgraph modeling method. Simulation results showed that when the rotor engaged with the armature, the response time of the current, the driver torque, the rotational speed and the relative sliding time between the driver and the driven side decreased, as the gap size between the rotor and the armature decreased and the number of coil turns increased. Also, when the rotor disengaged with the armature, the delay time increased with the decreased gap size and the increased number of coil turns. It was found that the experimental results of the current, the driver torque, the rotational speeds were in good accordance with the theoretical results. The results of this study can be used as basic design materials of the electro-magnetic clutch.

• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.6
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• pp.1-7
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• 2013

This paper focuses on cooling fan control by using a magnetic clutch type for the improvement of fuel economy on a heavy city bus. In general, Heavy duty vehicles use viscous clutch type cooling fan which has some disadvantages, such as slow response, wide temperature variation of engine coolant water. But a magnetic clutch type cooling fan can be controlled electronically so the engine coolant temperature can be precisely controllable and this effects could be used to reduce fuel consumption. A control system for applying the magnetic clutch type cooling fan was developed in this study and applied to the real field test and chassis dynamometer test. The result showed well controlled coolant temperature and enhancement of fuel economy.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.1259-1265
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• 2004

Electro-magnetic clutch which is affected by elements of electric, magnetic and mechanical friction is important that it has a characteristic changes by environmental impact. Expecially, it is equipped in railroad sideway which is bleak external environment. Therefore, this paper investigated affections by temperature changes, which can make out through physical characteristics such as friction torque, minimum slipping torque, rated slipping torque of electro-magnetic dutch.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.4
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• pp.111-116
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• 2011

This paper deals with the electromagnetic clutch which stop the generator at emergency by using the engine power of generator. The electromagnetic field was analyzed using Flux-2d program with different conditions : voltage, air gap, coil locations. As a result, the maximum magnetic flux density of electromagnetic clutch occurred between the coil and wheel : 0.27[T], 0.41[T] at 12[V], 24[V]. The maximum flux density was at the center location of the coil.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.8 no.1
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• pp.57-63
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• 2009

Magneto-Rheological(MR) fluid composes of a base fluid and ferromagnetic particles less than tens of micrometer size dispersed in the fluid. It is called as a smart material because its rheological properties are changable by a magnetic field. Its important applications are active devices such as controllable dampers and controllable clutches. The merit of those products is that their functional characteristics are controllable such that they enable active control strategies. This paper proposes an idea for machine tool applications of the MR fluid clutch as a safety device for power transmission. FEM has been used for magnetic field analyses and the results are compared with some former experiments. Some design syntheses of the MR clutches are suggested and hopefully considered that it may be an effective safety device for power transmission of machine tools.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.19 no.8
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• pp.795-801
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• 2009

This paper presents an optimal design of a magnetorheological(MR) fan clutch based on finite element analysis and also presents torque control of engine cooling fan using a sliding mode control. The MR fan clutch is constrained in a specific volume and the optimization problem identifies the geometric dimension of the fan clutch that minimizes an objective function. The objective function for the optimization problem is determined based on the solution of the magnetic circuit of the initially designed clutch. Under consideration of spatial limitation, design parameters are optimally determined using finite element analysis. After describing the configuration of the MR fan clutch, the viscous torque and controllable torque are obtained on the basis of the Bingham model of MR fluid. Then, a sliding mode controller is designed to control the torque of the fan clutch according to engine room temperature and control performance is evaluated through computer simulation.