• 한국기계가공학회지
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• 제13권5호
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• pp.57-63
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• 2014

At present, a high-speed swivel tool head of a small size is required to improve the productivity of CNC automatic lathes. Hence, there is growing interest in shorter machining times with higher cutting speeds. However, an increase in the rotation speed of a swivel tool head also has adverse effects, such as vibration and noise caused by the swivel tool head system. In this work, the fatigue life and contact pressure of a swivel tool head bearing system driven by gears were calculated. Based on the calculated results, a prototype swivel tool head was manufactured and its static and dynamic characteristics, i.e., the vibration, noise and precision, were measured using a reliability testing device which allows the application of cutting force to the end of the swivel tool head.

• 한국기계가공학회지
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• 제13권5호
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• pp.8-14
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• 2014

A slewing reducer consists of two planetary gearsets which require a good load distribution over the gear tooth flank for enhanced durability. This work investigates how the bearing characteristics influence the load distribution over the gear tooth flank. A complete system model is developed to analyze a slewing reducer, including the non-linear mesh stiffness of the gears and the non-linear stiffness of bearings. The results indicate that the type, arrangement and preload of the output shaft bearings greatly influence the gear mesh misalignment, contact pattern, face load factor, gear safety factor and lifetimes of the parts.

• 대한기계학회논문집A
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• 제29권2호
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• pp.188-200
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• 2005

Control of a multi-fingered robotic hand is usually based on the theoretical analysis for kinematics and dynamics of fingers and of object. However, the implementation of such analyses to robotic hands is difficult because of errors and uncertainties in the real situations. This article presents the control method for estimating the kinematic constraint of an unknown object by active sensing. The experimental system has a two-fingered robotic hand suspended vertically for manipulation in the vertical plane. The fingers with three degrees-of-freedom are driven by wires directly connected to voice-coil motors without reduction gears. The fingers are equipped with three-axis force sensors and with dynamic tactile sensors that detect slippage between the fingertip surfaces and the object. In order to make an accurate estimation for the kinematic constraint of the unknown object, i.e. the constraint direction and the constraint center, four kinds of the active sensing and feedback control algorithm were developed: two position-based algorithms and two force-based algorithms. Furthermore, the compound and effective algorithm was also developed by combining two algorithms. Force sensors are mainly used to adapt errors and uncertainties encountered during the constraint estimation. Several experimental results involving the motion of lifting a finger off an unknown object are presented.

• 전자공학회논문지T
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• 제36T권1호
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• pp.71-78
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• 1999

본 논문은 외부에서 공급받는 에너지 대신에 현가 시스템 자체에서 전기에너지를 발생시켜 전기우동(electro-rheological, 이후ER)유체를 제어하는 새로운 형태의 ER 진동 제어장치를 제안한다. 이를 위하여 에너지 재생 메커니즘을 개발하고 진동에너지를 재생 전기에너지로 환원하여 축적시켰으며, 상기에서 얻어진 저전압을 ER제어 할 수 있는 고전압(1KV-6KV)으로 승압시켜 ER 현가 장치에 적용하였다. 한편 제안된 장치의 성능 향상을 목적으로 재생 에너지의 충전장치, 고전압 발생장치, 전기제어장치, 신호감지장치를 설계하여 ER 현가 장치의 동특성 시험을 행하고 충격제어 능력을 평가하여 실용화 할 수 있는 기반을 구축하였다.

• 한국의상디자인학회지
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• 제12권2호
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• pp.1-20
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• 2010

This thesis is about "manggon" that holds down man's top knot hair and its accessaries "pungjam", "kwanja". manggon was seen first time in the mural of Donwhang kae won chon bo during T'ang period (713-756). The "Tu Aek Ra" manggon shown in this mural would be the origin and beginning of maggon's usage. Also the "Sha" that was placed on top of the hair for decoration purpose is believed to be a former form of "manggon" Before the short hair cut was enforced, wearing the "kwan"(head gear) was considered as an impotant etiguette. Thus the head gear was treasured and the manggon which was the most essential piece to cover down the hair before to put on the head gear was regarded as the most important piece. However, since the manggon was tied very tightly around the forehead, manggon caused some sickness. From my private collections of man's head gears and ornament, 121 items were selected and used for analysis and the followings were found: 1. Pungjam was divided into 8 categories according to its shape and a research was made on its unique structural characteristic on each categories. 2. Kwanja's material and design that were used are all in accordance to the historical recordings.

• 대한기계학회논문집
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• 제15권1호
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• pp.154-162
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• 1991

본 연구에서는 내치차의 절삭가공에서 발생하는 치형오차를 대상으로 이에 영 향을 미치는 제반 조건 중, 커터의 이론적인 인벌류트 치형으로부터의 편차, 커터와 내치차의 잇수에 의한 간섭, 창성과정(generating process)중 원주방향 이송과 같은 가공조건이 기어의 치형오차에 미치는 영향을 분석하고 이를 최소로 하는 조건을 유도 하여 양질의 내치차 생산에 기여 하고자 한다.

• 대한기계학회논문집A
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• 제26권8호
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• pp.1506-1511
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• 2002

A computer aided expert system fur spur, helical, bevel and worm gears was newly developed by using AutoiCAD system and its AutoLISP computer language in the present study. Two methods are available for a designer to draw a gear. The first method needs the gear design parameters such as pressure, module, number of tooth, shaft angle, velocity, materials, etc. When the gear design parameters are inputted, a gear is drawn in AutoCAD system and maximum allowable power and shaft diameter are calculated additionally. The second method calculates all dimensions and gear design parameters to draw a gear when the information such as transmission, reduction ratio, nm, materials and pressure are inputted. The system includes four programs. Each program is composed of a data input module, a database module, a strength calculation module, a drawing module, a text module and a drawing edit module. In conclusion, the CAD system would be widely used in companies to find the geometric data and manufacturing course.

• 대한기계학회논문집A
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• 제25권1호
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• pp.39-46
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• 2001

When designing a gear, designers determine basic dimensions of a gear with transmitted power considering strength, interference and so on. But, designers can not easily obtain the tooth profile generated by dimensions as well as the geometry of generating hob for cutting the tooth profile. In order to resolve these problems, an automatic design system creating not only the solid model of a gear but also that of the generating hob using the design parameters of dimensions is developed. Through the developed system, designers system, designers can improve the efficiency of design and satisfy the variable requirements of design as well. In this research, the three-dimensional solid models for spur and helical gears are generated considering the design parameters. Besides, those for generating hob regarding the design parameters of hob is created automatically. The system is developed by using Visual Basic and its three-dimensional geometric modeling module is constructed by using SolidWorks.

• 한국기계가공학회지
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• 제14권6호
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• pp.98-103
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• 2015

Swing reducers are widely used in special vehicles that have swing motions. Generally, compact swing reducers were constituted by a worm gear pair. Worm gears are one of the most important technical devices for transmitting torque between spatially crossed axes. Due to their high transmission ratio and compact structure, they are widely used in power transmission applications where high reduction is required. This paper presented approaches to improve the transmission efficiency and assembling performance of 3.5 ton class worm gear swing reducers. Worm wheel and the case of swing reducers were optimized and certified by a finite element method. Finally, an actual swing reducer was processed and assembled to test the performance.

• 한국기계가공학회지
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• 제15권1호
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• pp.14-19
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• 2016

Transmission error (TE) is the most important cause of gear noise and vibration because TEs affect the changes of the force and the speed of gears. TE is usually expressed as an angular deviation, or a linear deviation measured at the pitch point and calculated at successive positions of the pinion as it goes through the meshing cycle. Accurate measurement of TE for gear transmission will provide a reasonable basis for gear design, manufacturing processes and quality control. Therefore, in order to study the accuracy of the gear transmission, stability, TE, vibration and noise after gear micro-geometry modification, a gear transmission test rig is proposed in this paper, which is based on the existing technical conditions, by using reasonable testing methods, hardware and a signal processing method. All of the details and the experience can be taken into consideration in the next upgraded test rig.