• 한국공작기계학회:학술대회논문집
• /
• 한국공작기계학회 2000년도 춘계학술대회논문집 - 한국공작기계학회
• /
• pp.561-566
• /
• 2000

A screw driver is essentially used in assembling machine parts and electronic products such as the printed circuit board with a housing. As the parts to be assembled becomes small and precise, the higher precision of the controling screw driver torque is required. However, because the operator controls the fastening torque by his experience, it must be inexact. Thus the screw driver which can exactly control the fastening torque by a bellows is designed and developed in the study. The bellows is expanded by the inner air pressure and contracted and by the spring operation. The bellows driver is composed of the entrance solenoid valve, the exit solenoid valve and the pressure sensor. The pressure sensor senses the bellows pressure. When the pressure sensor output reaches the setting value, it operates the exit solenoid valve not to deliver further torque by letting the air of the bellows out. Through a series of experiments, the performance is studied and verified.

• 한국공작기계학회논문집
• /
• 제10권5호
• /
• pp.53-59
• /
• 2001

A screw driver is widely used in assembling machine parts or electronic products such as the printed circuit board with a housing. As the parts to be assembled becomes small and precise, the higher precision of the controlling screw driver torque is required. However, because the operator controls the fastening torque based on experience, it must be inexact and the setting procedure will be time consuming job. Thus the screw driver which can exactly control the fastening torque is developed utilizing a bellows in this paper. The bellows is expanded by the inner air pressure and contracted by the spring operation. The bellows type driver is composed of a clutch mechanism with two solenoid valves and a pressure sensor. Those valves are controlled using the detected bellows pressure by the sensor. When the pressure reaches the setting value, the exit solenoid valve is opened to release the air pressure from the bellows so as not to deliver further torque. Through a series of experiments, the performance is examined and verified.

• 국제지역연구
• /
• 제13권2호
• /
• pp.66-88
• /
• 2009

우리는 경제 내에 불확실성이 있을 경우의 최적 통화정책 준칙을 살펴본다. 특히 총수요에 대한 주택가격의 효과 뿐 만 아니라 주택가격 상승률에 관한 두 가지 가능한 영역을 허용한다. 두 가지 상태에 대한 불확실성이 Markov 상태 변환으로 모형화 된다. 미국 자료에 대한 예비 추정 결과는 두 개의 다른 상태 즉 정상 상태와 주택가격 버블 상태 영역의 존재를 확인한다. 다음으로, 본 연구에서는 주택시장에 두 개의 상태가 존재할 경우 중앙은행의 최적통화준칙을 살펴본다. '통상적' 상태 하에서는 인플레이션 압력에 반대로 대응해야 하는 반면, 버블 상태에서는 인플레이션 압력을 수용해야 한다는 면에서 중앙은행의 최적통화정책은 비대칭적이다. 또한, 미래 상태에 대한 불확실성이 있을 경우 더욱 보수적으로 통화정책을 운용해야 한다는 결과를 도출한다.

• 한국기계가공학회지
• /
• 제21권7호
• /
• pp.84-90
• /
• 2022

The purpose of the cover housing component of a car door is to protect the terminals of the plug housing that connects the electric control unit on the door side to the car body. Therefore, for a smooth assembly with the plug housing and to prevent contaminants from penetrating into the gaps that occur after assembly, the warpage of the cover housing should be minimized. In this study, to minimize the warpage of the cover housing, optimization was performed for design factors related to the mold and processes based on the injection molding simulation. These design factors include gate location, gate diameter, injection time, resin temperature, mold temperature, and packing pressure. To optimize the design factors, Taguchi's approach to the design of experiments was adopted. The optimal combination of the design factors and levels that minimize warpage was predicted through L₁₈-orthogonal array experiments and main effects analysis. Moreover, the warpage under the optimal design was estimated by the additive model, and it was confirmed through the simulation experiment that the estimated result was quite consistent with the experimental result. Additionally, it was found that the warpage under the optimal design was significantly improved compared to both the warpage under the initial design and the best warpage among the orthogonal array experimental results, which numerically decreased by 36.9% and 23.4%, respectively.

• Design & Manufacturing
• /
• 제17권1호
• /
• pp.48-55
• /
• 2023

In this study, on the structure simulation for manufacturing a high strength/light weight 48V battery housing for a mild hybrid vehicle was conducted. Compression analysis was performed in accordance with the international safety standards(ECE R100) for existing battery housings. The effect of plastic materials on compressive strength was analyzed. Three models of truss, honeycomb and grid rib for the battery housing were designed and the strength characteristics of the proposed models were analyzed through nonlinear buckling analysis. The effects of the previous existing rib, double-sided grid rib, double-sided honeycomb rib and double-sided grid rib with a subtractive draft for the upper cover on the compressive strength in each axial direction were examined. It was confirmed that the truss rib reinforcement of the battery housing was very effective compared to the existing model and it was also confirmed that the rib of the upper cover had no significant effect. In the results of individual 3-axis compression analysis, the compression load in the lateral long axis direction was the least and this result was found to be very important to achieve the overall goal in designing the battery housing. To reduce the weight of the presented battery housing model, the cell molding method was applied. It was confirmed that it was very effective in reducing injection pressure, clamping force and weight.

• 한국섬유공학회:학술대회논문집
• /
• 한국섬유공학회 1999년도 봄 학술발표회 논문집
• /
• pp.300-304
• /
• 1999

A study is strength analysis of a filtering structure for a viscoelastic flowing substance. Conventional segment type filter units comprise an assembly of two or more individual disc segments stacked at their respective hubs on a central common filtrate collection tube within a filter housing. The conventional type's leaf disc is problem that it don't support a high pressure flows. Therefore, this study develope new structure filtering model to stand a high pressure flows.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2001년도 추계학술대회 논문집
• /
• pp.77-81
• /
• 2001

The present study is concemed with the design of high pressure container reinforced by winding wire used as a die component in cold forming of metals. The stress analysis for the design of high pressure container has been made under an optimal design criterion. The wire-winding equipment and the tension control unit according to the theoretical winding force are installed. The circumferential stresses at the inner wall of die housing are measured every turn of wire-winding. The measure stresses are in good agreement with the analytically predicted ones.

• 부동산연구
• /
• 제28권4호
• /
• pp.75-88
• /
• 2018

본 연구는 주택담보대출 가산금리가 주택담보대출에 미치는 영향을 분석하는데 그 목적이 있다. 특히, 가산금리의 구조적 변화 여부, 구조적 변화가 존재할 경우 그에 따른 주택담보대출로의 영향을 면밀하게 분석하고자 한다. 실증분석을 위해 주택담보대출, 주택담보대출금리, COFIX금리, 가산금리를 이용하였으며, 분석기간은 2010년 12월부터 2017년 12월까지이다. 분석결과, 가산금리와 주택담보대출에 통계적으로 유의한 구조적 변화가 존재(각각 2015년 5월과 6월)하였으며 가산금리의 구조적 변화가 주택담보대출의 구조적 변화에 영향을 미친 것으로 추정된다. 가산금리는 기준금리인 COFIX금리와 대출금리인 주택담보대출금리보다 주택담보대출에 더 큰 영향을 미치는 것으로 나타났으며 가산금리가 주택담보대출에 큰 부담으로 작용하는 것으로 나타났다. 대내외적으로 경제의 불확실성이 증가하고 있는 상황에서 금리인상에 대한 압력이 가중되고 있다. 이러한 환경과 여건 등을 고려해 볼 때 향후 금리인상은 불가피할 전망이다. 현재 우리나라의 경제수준에서 기준금리와 가산금리가 동시에 증가하게 된다면 가계의 대출 상환 및 이자에 대한 부담이 가중되어 경기침체로 이어질 것이 자명하다. 따라서 객관적이고 투명하지 못한 은행의 자의적인 가산금리 산정을 사전에 방지하여 금융소비자를 보호할 수 있도록 금융당국의 제도적 장치 마련이 시급하다.

• 토지주택연구
• /
• 제2권2호
• /
• pp.163-170
• /
• 2011

개별진공압공법은 지반에 타설된 연직배수재에 진공압을 직접 가하여 간극수를 배출하여 일정한 전응력 상태에서 유효응력이 증가함에 따라 압밀을 촉진 시키는 공법이다. 연약지반 개량에 일반적으로 사용되는 공법인 성토재하공법(preloading)과는 다르게 성토하중이 필요로 하지 않기 때문에 성토재료의 확보 문제와 지반의 국부적인 전단파괴에 대해 이점을 가지고 있다. 또한 기존의 진공압밀 공법에서의 문제점인 펌프효율의 감소, 고가의 기밀시트에 소요되는 비용, 그리고 기밀시트의 잦은 파손의 문제 등을 직접적으로 배수재에 진공압을 가함으로서 개선시킨 공법이다. 그러나 개별진 공압공법은 직접 고압의 진공압을 직접 배수재에 가함으로써 배수재 주변의 투수계수가 감소하며 경화되는 영역(hardening zone)과 필터재료의 막힘현상(clogging)에 의해서 간극수의 배출이 줄어들게 되어 지반개량의 효율이 크게 감소하게 된다. 따라서 본 연구에서는 높은 지반개량 효과를 얻을 수 있는 진공압의 적용기간을 찾기 위해서 단계진공압(-20, -40, -60, -80KPa) 적용기간을 각각 다르게 적용하였다. 실험을 진행하는 동안 각 조건에 따라 개량 시간에 따른 침하량을 측정하였으며, 실험 종료 후 최종침하량, 함수비, 콘저항치를 측정하였다. 파악된 데이터를 비교/분석하여 개별진공압공법에 적합한 단계진공압 적용기간을 도출한 후 수치해석을 실시하여 제안된 단계진공압 적용에 따른 침하량을 예측하였다.

• 한국산업융합학회 논문집
• /
• 제9권4호
• /
• pp.301-308
• /
• 2006

Today's automobiles are changing into miniaturization and light weight for saving natural resources and energies. In order to raise the sufficiency of fuel consumption, new mechanism and components are required. Therefore, the expectations on the new materials are very high. Especially, Al materials are widely used to reduce the motors weight. Al using in automobiles is mostly casting material, and the material is developing rapidly in step with technical innovation. Al die casting has become an important field, as we are turning today's motor into light weight. One of the parts in steering system, valve housing, plays a role to reduce the operating effort of drivers. If valve housing being a part of steering system is produced by gravity casting, the space that manufacturing equipments are installed will be increased, and more energies and workers will be needed.