• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.19 no.8
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• pp.788-794
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• 2009

Various types of latch designs for hard disk drives using load/unload mechanism have been introduced to protect undesired release motions of a voice coil motor(VCM) actuator from sudden disturbances. Recently, various inertia-type latches have been widely used because locking performance is better than that of other types of latch. However there has been a limit in the inertia type in order to guarantee perfect latch and unlatch operations because of changes in latch/unlatch conditions due to mechanical tolerance and temperature-dependent friction. In this paper, a reliable and robust magnetic latch mechanism is proposed through only simple modifications of coil and yoke shapes in order to overcome the mechanical limit of current inertia-type latches. This new magnetic latch does not have only a simple structure but it also ensures reliable operations and anti-shock performance. The operating mechanism of the proposed latch is theoretically analyzed and optimally designed using an electromagnetic simulation.

• Nuclear Engineering and Technology
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• v.53 no.12
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• pp.4166-4178
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• 2021

The Control Rod Drive Mechanism (CRDM) is an essential part of the reactor, which realizes the start-stop and power adjustment of the reactor by lifting and lowering the control rod assembly. As a moving part in CRDM, the latch directly contacts with the control rod assembly, and the life of latch is closely related to the service life of the reactor. In this paper, the relationship between the life of the latch and the step stress, friction stress, and impact stress in the process of movement is analyzed, and the optimization methodology and process of latch life based on the approximate model are proposed. The design variables that affect the life of the latch are studied through the experimental design, and the optimization objective of design variables based on the latch life is established. Based on this, an approximate model of the life of the latch is built, and the multi-objective optimization of the life of the latch is optimized through the NSGA-II algorithm.

• Journal of the Korean Society for Precision Engineering
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• v.33 no.8
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• pp.655-660
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• 2016

Self-closing drawers are used in high-end products, such as furniture, home appliances, and a range of other storage devices. In this study, a self-closing mechanism is proposed. A system consisting of a friction latch, constant force spring, rotary damper with rack, and pinion is developed. The retracting drawer can be latched at any position and can be reactivated by simple touch. The constant force spring and rotary damper offer smooth closing action. The ergonomic quality of the closing action is quantified by an index based on velocity-time behavior. The effects of various design parameters are analyzed with a dynamics model and experimentally validated by prototype testing.

• Journal of Auto-vehicle Safety Association
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• v.15 no.1
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• pp.7-15
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• 2023

The purpose of this study is to predict the dynamic behavior of clamshell hood system on the harsh road driving condition, and secure the safety and durability performance of the system. The equation of motion of hood system is derived and the numerical analysis is implemented to obtain the lateral movement of the hood system. Also, the actual Belgian road test results are correlated to the predicted ones, and confirm the reliability of the system. Then, the parameter study is conducted to figure out the sensitive factors to affect the dynamic behavior, and the engineering design guide to make the system robust to confine the minimum friction force generated from hood latch and maximum hood weight is suggested from this research.

• Proceedings of the KIEE Conference
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• 2003.11c
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• pp.555-558
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• 2003

When a fault relating to the urgent alarm occurs, we must prevent control rods from dropping and make one of two grippers in Control Rod Drive Mechanism (CRDM) grip the drive rod laking a control rod assembly. If a gripper with any problem is ordered to grip the drive rod, the gripper which cannot latch the rod stably will fail to take the rod. On the purpose of escaping this bad case, we order two grippers to hold the drive rod and enhance the reliability of holding control rods. This action is called the double hold. In the middle of the movement of the drive rod, the latching of the drive rod can cause friction between a gripper and the drive rod. This state may give damage to both the gripper and the drive rod. In this paper, we have devised the method which can have two grippers hold the drive rod more stably, without damaging the equipment.