• 소성∙가공
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• 제13권4호
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• pp.359-364
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• 2004

In the multi-stage former, a manufacture of hexagonal fitting nut was generated in a defective products about 70∼80% in the industry field. Products generated in defects manufactured to be a machining about 60%. Additional process increased a product cost and decreased a product rate. Therefore, it is important to predict and design a preform reducing defective products in the early stage of process design. So in the study Defects for manufacturing hexagonal fitting nut verified a cause through the finite element simulation. To reduce a defective generation. a preform designed and a designed preform verified through the finite element simulation. In conclusion, a generated defects when a hexagonal fitting nut manufactured should reduce if a round dimension of preform reduced and a part of opposition angle distributed in plenty a volume.

• 동력기계공학회지
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• 제21권2호
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• pp.41-47
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• 2017

Boron steel (51B20) was cold forged using by new designed dies to apply for automotive aluminum wheel nut. The formability and mechanical properties of boron steel were compared with carbon steel(S45C) which has been used up to date for the wheel nut material. The formability was investigated on the dies designed with various types of punch nose using by FEM. The metal flow and compressive stress on the dies during cold forging were investigated and compared each other. The forging process with a new designed die showed the improved metal flow with a reduced forging load which resulted in the significant increase of the die life. It was recommended that the carbon steel for automotive wheel nut material could be substituted by the boron steel.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.1858-1861
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• 2005

Automatic nut sorting machine used to calculate the size of inserted nut and detect the black spot defection is introduced in this paper. Because most of farm products are imported from the underdeveloped countries, domestic farm products have no place to be sold in market. To overcome this critical situation, lowering the productivity cost is strongly demanded to compete with foreign corps. Imaged processed nut sorting algorithm is developed to the automatic nut sorting machine to remove the sorting time which takes lots of man power. This system is composed of mainly two parts, mechanical parts and vision system. The purpose of mechanical part is supplying the nuts automatically to make computer system capture the images of objects. Simplified mechanical system was assembled followed by 3D simulation by Pro/E design for the adaptive cost effects. Several image processing algorithms are designed to detect the spot defects and calculate the size of nuts. Test algorithm shows good results to the designed automatic nut sorting system.

• 한국강구조학회 논문집
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• 제12권2호통권45호
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• pp.143-150
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• 2000

마찰접합용 고장력 볼트 셋트의 관련 규격에서 허용하는 치수공차 범위 내에서 너트 구멍의 편심과 와셔 구멍 지름의 공차는 체결 시 편심에 의한 접촉면적의 결손을 초래하고 체결력의 산포를 유발하는 요인이 된다. 편평한 너트 자리면과 와셔의 접촉시 분포되는 압력의 비선형성을 고려하여 편평한 자리면 형상을 원호곡면으로 바꾸면 초기 선 접촉은 체결이 진행됨에 따라 면 접촉으로 발전한다. 원호 접촉면은 편심에 의한 접촉면적의 결손을 감소시켜 접촉상태가 양호해지므로 자리면 마찰토크(체결력) 안정화에 기여하게 된다. 유한요소법으로 너트와 와셔 접촉면의 압력을 구하고 나사면과 자리면의 마찰계수는 토크계수 A, B급이 포함되도록 조합하고 최대편심 시 토크계수를 계산하였다. 토크계수의 분포로부터 원호자리면의 적정 곡률반지름이 결정된다.

• 소성∙가공
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• 제21권8호
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• pp.493-498
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• 2012

A wheel nut wrench is one of the hand tools used to loosen and tighten lug nuts on automobile wheels and it has generally a solid-type geometry for commercial vehicles. However, the solid-type wheel nut wrenches manufactured by hot forging processes exhibit several drawbacks such as heavy weight and rough surface finish. Thus, many efforts have been devoted to change the part geometry and improve the manufacturing process. For this purpose, the weight of the final product can be reduced drastically using a hollow tube as the initial stock, which can be manufactured by the more economical manufacturing process of cold forging. In this study, the cold forging of a hollow-type wheel nut wrench for commercial vehicles was designed based on the results of fundamental experiments and CAE analyses using the commercial finite element code DEFORM-3D. In addition, cold forging experiments were conducted on a special-purpose forming machine for hollow wheel nut wrenches in order to validate the designed process sequence. As results, it was found that the final products with a weight reduction of 39% and better surface appearance can be manufactured without any defect with the newly designed cold forging process.

• 대한기계학회논문집
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• 제13권3호
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• pp.353-361
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• 1989

본 논문에서는 유한 요소법을 이용하여 접촉을 고려한 나사 체결 문제를 해석하고 여러 다른 체결조건이 각 나사산에 걸리는 하중 분담율에 미치는 영향을 살펴보고, 이 하중 분담율이 보다 균일화 될 수 있는 체결 조건을 찾고, 또 그때의 응력 분포를 살펴보는 것을 목적으로 한다.

• 한국식품저장유통학회지
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• 제17권3호
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• pp.376-383
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• 2010

견과류 중 sunflower seed, cashew nut, walnut, pistachio, pumpkin seed, ginkgo, hazel nut, pecan을 원료로 하여 지방산 조성 분석 및 sn-2 position 분석, triacylglycerol species의 분석, tocopherol, phytosterol 함량을 분석하였다. 조지방 함량은 hazel nut에서 약 39.60 wt%로 가장 높았으며, walnut 35.25 wt%, pistachio 30.22 wt% 등의 순이었다. GC에 의한 sn-2 위치의 지방산 조성 분석 결과, oleic acid의 함량이 많은 견과류는 cashew nut, pistachio, hazel nut, pecan 이였으며, 특히 ginkgo의 경우 특이적으로 oleic acid의 이성체인 vaccenic acid가 10.72 wt% 나타냄을 확인할 수 있었다. 반면, linoleic acid 등이 높은 견과류는 sunflower seed, walnut, pumpkin seed 이었다. 견과류들의 TAG species의 PN값은 40∼52 사이에 존재하였다. Tocopherol의 함량은 ginkgo, sunflower seed, pumpkin seed 등에서 각각 48.57, 38.35, 31.43 mg/100 g 순으로 높은 함량을 나타내었다. 또한 총 phytosterol의 경우 88.60∼947.20 mg/100 g 사이에 함량을 나타내었다.

• 한국식품과학회지
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• 제10권2호
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• pp.119-123
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• 1978

은행의 종실 및 잎중에서 추출 정제한 유지에 대한 지방질의 구성 및 지방산 조성을 분석한 결과를 요약하면 다음과 같다. 1) 신선한 종실 및 잎중의 정제한 총지방질의 함량은 각각 1.32% 및 2.24%였다. 2) 종실중의 총지방질중에는 중성지질이 약 89%, 복합지질이 약 10% 함유되어 있는데 반하여 잎중에는 중성지질이 약 28%, 복합지질이 약 72% 함유되어 있었다. 3) 종실중의 중성지질의 구성분은 다른 식물성 유지와 같이 triglyceride가 주성분으로 약 86%함유되어 있었으며, esterified sterol이 약 9%로 그 다음으로 많았다. 그러나 잎중에는 esterified sterol이 약 53%로 가장 많았고 triglyceride는 약 18%에 불과하였다. 4) 종실중의 총지방질의 주요한 구성지방산은 oleic acid(37.5%) 및 linolenic aicd(44.5%)이고, 잎의 주요 지방산은 linoleic acid(45.2%) 및 palmitic acid(25.1%)였다. 또 종실과 잎중의 중성지질을 구성하는 지방산 조성은 서로 비슷하고, oleic, linoleic 및 palmitic acid가 주요 지방산이었다. 그리고 당지질을 구성하는 지방산조성은 종실에는 oleic 및 linoleic acid의 함량이 잎보다 많은데 비하여 linolenic acid의 함량은 잎이 종실보다 훨씬 많았다. 인지질을 구성하는 지방산조성은 종실과 잎이 모두 당지질과 비슷한 경향이었다.

• Journal of Welding and Joining
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• 제34권2호
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• pp.1-10
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• 2016

The use of materials for modern lightweight auto-bodies is becoming more complex than hitherto assemblies. The high strength materials nowadays frequently used for more specific fields such as the front and rear sub frames, seat belts and seats are mounted to the assembled body structure using bolt joints. It is desirable to use nuts attached to the assembled sheets by projection welding to decrease the number of loose parts which improves the quality. In this study, nut projection welding was carried out between a nut of both boron steel and carbon steel and ultra-high strength hot-stamped steel sheets. Then, the joints were characterized by optical and scanning electron microscope. The mechanical properties of the joints were evaluated by microhardness measurements and pullout tests. An indigenously designed sample fixture set-up was used for the pull-out tests to induce a tensile load in the weld. The fractography analysis revealed the dominant interfacial fracture between boron steel nut weld which is related to the shrinkage cavity and small size fusion zone. A non-interfacial fracture was observed in carbon steel nut weld, the lower hardness of HAZ caused the initiation of failure and allowed the pull-out failure which have higher in tensile strengths and superior weldability. Hence, the fracture load and failure mode characteristics can be considered as an indication of the weldability of materials in nut projection welding.

• Journal of Nutrition and Health
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• 제35권2호
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• pp.171-182
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• 2002

This study wa performed to investigate the effect of dired powder of chestnut and acorn on lipid metabolism, antioxidative capacity and antithrombotic effect in rats. Fifty-four male Sprague-Dawley rats weighing 199$\pm$17g were blocked into nine groups according to their body weight. Rats were raised with diets containing only flesh or flesh with inner skin of 5% and 10% dried nut powders for four weeks. Food intake, body weight gain, food efficiency ratio and organ weight were no different among the experimental groups. The plasma and liver lipid levels of all the nut diet groups were lover than those of the control group. The nut diets showed hypolipidenic effect in the plasma and liver. Plasma and liver thiobarbituric acid reactive substance (TBARS) concentrations were significantly decreased in all the nut diet groups. The plasma TBARS levels of the inner skin groups were significantly different from the control group dose-dependently. Superoxide dismutase(SOD) activity was significantly different among the experimental groups, and all the nut groups showed higher activity than the control group. There were significant differences in SOD activity between the chestnut and acorn groups and the chestnut groups showed higher erythrocyte SOD activity and the acorn groups showed higher liver SOD activity than the other groups. Whereas catalase and GSH-Px activities in the erythrocyte and liver of both nut groups showed a tendency to increase, they were not significantly different among the experimental groups. The bleeding time and whole blood clotting time tended to be extended by feeding both types of nut but they were not significantly different among the experimental groups. Production of TX $B_2$ and PG $F_{1{\alpha}}$ was no different among the experimental groups. These results suggest that chestnut and acorn diets have the effect of lowering plasma and liver lipid levels, inhibiting lipid peroxide formation and increasing antioxidative enzymes activity. Thus, it is plausible that chestnut and acorn could be recommended in the treatment and prevention of cardiovascular diseases.