• Industry Promotion Research
• /
• v.1 no.2
• /
• pp.1-6
• /
• 2016

By using the high tensile steel plate (SPFH590) 1 Primary normal shear process clearance was studied through an experiment for the effect of the second shaving process in this study. Experiment result, Shaving process in the case of processed 15% of the Primary normal shear process clearance was some residual surface does not remove it completely. and Shaving process of shearing products by the general shearing process clearance of 10% it was found that the wider the size of shear surface. The shear surface of 93% occurred in case of the clearance of general shearing process is 10% and the Shaving clearance is 2%, The shear surface of 87% were to occur in case of the Shaving clearance is 3%.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.34 no.2
• /
• pp.179-184
• /
• 2010

This experimental study investigated the effect of tip clearance and bypass flow on the cooling performance of a straight fin heat sink. Both the horizontal and vertical directions of the bypass flow were studied by using a mass flow controller and test sections. The thermal resistance of a heat sink was obtained to elucidate the response of the cooling performance to tip clearance and bypass flow. The thermal resistance of a straight fin heat sink gradually increases with increasing tip clearance. A flow guide unit was employed to reduce the bypass flow. An optimal distance from the leading edge of the heat sink to the flow guide unit was found for the fixed volume flow rate. The contribution of the flow guide unit to the thermal performance of a heat sink increases with increasing volume flow rate.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.14 no.12
• /
• pp.6060-6065
• /
• 2013

Minimizing the height of the die roll is very important for maximizing the size of effective shear planes. In this study, the die roll change was investigated for the change in the amounts and clearance of the V-ring indentation. Shear analysis and experiments were conducted with the V-ring distance fixed to 2mm. Fine blanking die was applied to the die insert with different clearances. Several specimens were analyzed about the height of the die roll. As a result, the pressure of V-ring effectively inhibited the flow of materials. And the height of the die roll was lowest when the clearance between the die and punch was 1% of the material thickness.

• Proceedings of the KSME Conference
• /
• 2004.04a
• /
• pp.1189-1194
• /
• 2004

In this paper, the effect of tip clearance on the cooling performance of the microchannel heat sink is presented under the fixed pumping power condition. For the various types of microchannel heat sink having different size of fin width and channel width, experimental study is conducted. Through the experiment, the tip clearance effect is investigated by increasing tip clearance from zero. As a result, it is shown that cooling performance of heat sink with tip clearance is better than that of heat sink without tip clearance. For the microchannel heat sink with tip clearance, the optimum conditions for cooling performance is also studied.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.34 no.11
• /
• pp.1623-1630
• /
• 2010

In this study, effective forming methods for reducing the roll-over of a sector tooth, which is a main component of an automotive seat recliner, are proposed. Due to the large amount of roll-over, accurate contact between the inner gear of a sector tooth and the outer gear of a pawl tooth cannot be normally achieved; thus sensitivity and safety for the passengers decrease. To overcome the aforementioned drawback, we investigated the effect of flowcontrol forming methods involving local embossing die, coining punch, and VIC (Variable Inverse Clearance) on the roll-over depth by FE-analysis and an experiment. The results of a fine-blanking experiment for verifying the proposed methods showed that VIC type is decidedly superior from the aspects of reduction of roll-over and tool strength of the sector tooth.

• Fire Science and Engineering
• /
• v.29 no.2
• /
• pp.33-38
• /
• 2015

For the purpose of high-pressure and suction of fixed amount, the development of ultra-high pressure rotating helical gear positive displacement pump with no clearance had been proceeded. The CFD analysis was performed to verify the internal pressure and the discharge flow velocity of the pump. Accordingly, a flow analysis were performed by FVM technique and we were unable to obtain a successful result since the fluid domain is separated because the grid is not configured in a row in FVM flow analysis of the fully enclosed type without clearance. Because of these problems, the flow analysis was performed by MPS method which grid configuration is not needed and the internal pressure and the discharge flow velocity of the pump were confirmed through the MPS flow analysis. At 1,000 rpm rotation speed of the rotor, the minimum internal pressure of the pump was 19.5 bar, maximum pressure was 44.6 bar and average pressure was 33.9 bar. And the minimum discharge flow velocity was 64.5 m/s, maximum discharge flow velocity was 84.8 m/s and average discharge flow velocity was 76.1 m/s. Through this study, we could confirm that MPS method was more suitable than FVM method in terms of flow analysis with no clearance. In addition, the relationship of the flow velocity according to the change of ultra-high pressure rotating helical gear positive displacement pump could be identified through this study.

• Korean Journal of Clinical Pharmacy
• /
• v.14 no.2
• /
• pp.91-95
• /
• 2004

당뇨환자가 합병증으로 고혈압이 있을 경우 항고혈압약물인 딜티아젬을 투여시 딜티아젬의 동태학적 측면에서 투여계획을 설계하기 위해서 토끼에 알록산을 당뇨병모델을 만들었다. 알록산으로 유도된 급성 및 만성 당뇨 토끼에서 딜티아젬의 약물동태 변화에 대한 결과는 당므과 같다. 1. Alloxan 45 mg/kg을 토끼의 귀정맥에 투여시 혈당농도는 control군에서 $112\pm20.6\;mg/dl$, acute DM군에서는 $260\pm897\;mg/dl$, chronic DM군에서는 $331\pm85\;mg/dl$으로 당뇨가 유발되었음이 확인되었다.. 2. Alloxan에 의한 당뇨병 유발토끼에서 딜티아젬의 혈중농도곡선하면적(AUC)값은 대조군$(21.6\pm2.45\;\mug/ml)$ 보다 chronic DM군$(31.91\pm379\;mg/ml{\cdot}hr)$에서 유의성(p<0.05) 있게 증가하였다. 3. 딜티아젬의 요중누적배설량은 대조군에 비해 acute 및 chronic DM군에서 감소되었으나 유의성은 없었다. 4. 당뇨병 유발 토끼에서 딜티아젬의 토탈바디클리어런스$(CL_t)$ 값과 $\beta$-소실속도정수값이 대조군에 배해서 유의성(p<0.05)있게 감소되었다. 실험적 당뇨 토끼에서 딜티아젬의 생체이용률의 증가는 딜티아젬의 토탈바디클리어런스$(CL_t)$ 값과 베타의 소실속도정수 값이 대조군에 비해서 유의성있게 감소되었기 때문으로 사료된다.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.28 no.3
• /
• pp.89-94
• /
• 2016

In this experimental study, the effects of top clearance on the performance of automotive a/c compressor were studied. Top clearance measuring device was also developed to ensure the reliability using vacuum conditions to secure constant control of top clearance without external environmental influence. Our results revealed that the improvements in compressor performance according to different top clearance values using the same compressor and same operator were about 4.12% at 800 rpm and about 7.8% at 2,000 rpm in 0.243~0.252 mm of top clearance compared to 0.431~0.456 mm of top clearance. To confirm the consistency in measuring top clearance affecting compressor performance, the top clearance measuring device was developed in this study using a vacuum pump. After performing reliable tests repeatedly, the distribution of measuring values under this device was within 0.99~1.83%, indicating that the constant test data in compressor performance was not affected by any other external environment.

• Journal of the korean Society of Automotive Engineers
• /
• v.4 no.3
• /
• pp.10-17
• /
• 1982

이글에서는 1. 마찰손실의 사고방식 2. 마찰손실의 내역과 제인자의 영향 1) 기계마찰에 대한 기관각부의 비율 2) 실린더 내압, 회전속도, 부하의 영향 3)윤활유점도의 영향 4) 행정/안지름비의 영향 5) 베어링축 및 오일클리어런스의 영향 6) 기관치수의 영향 7) 모우터링시와 발화운전시의 마찰손실의 비교 3. 마찰에 의한 경제적 손실 등에 관하여 알아보았다.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2004.10a
• /
• pp.1440-1443
• /
• 2004

Shearing including punching, blanking, trimming, slitting, etc is one of the most frequently used processes in sheet metal manufacturing. It has been widely used for manufacturing autobody, electronic components, aircraftbody, etc. In this paper, it has been researched by the experiment to examine the effect of burr height corresponding to die clearance, cutting angle, tool sharpness, etc. This paper presents the experimental results with using Al alloy sheet.