• 한국자동차공학회논문집
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• 제17권1호
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• pp.80-86
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• 2009

Main bearing cap is one of the essential structural elements in internal combustion engine. Main bearing cap guides and holds the crankshaft, withstanding the full combustion and inertia loads of the engine. A seamless design methodology using FEA has been proposed to produce a reliable design of main bearing cap. A Levy's thick cylinder model was applied to calculate the contact pressure between bearing shell and housing bore. A calculated contact pressure at housing bore is within the allowed limit comparing with that from bearing shell model. An adequate FEA model was suggested to obtain reliable solutions for the durability of main bearing cap. 3D global model consists of engine bulkhead, main bearing cap, and bolts. Sub-model consisting of cap and part of bolts is used to get detailed solution of main bearing cap. A very careful contact modeling practice is needed to resolve the convergence problems frequently encountering during combined geometric and material non-linear problems. A proposed methodology has been applied to the main bearing cap model successfully and obtained reliable stress results and fatigue safety factors.

• Journal of Mechanical Science and Technology
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• 제16권8호
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• pp.1095-1101
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• 2002

The load characteristics of engine main bearing are very important in the design of crankshaft and engine block. The stiffness of crankshaft and block, or the optimal dimension of the bearing can be determined according to the load level. This paper presents the load characteristics of engine main bearing. Two components of the main bearing load are measured during engine firing and motoring. The vertical and horizontal load components are measured by using the dynamic load cell mounted in each main bearing cap bolt. The measured main bearing loads are compared with calculated results by using the statically determinate method. The theoretical results, provided in this study, agreed well with the experimental results. The presented results are very useful for achieving optimal design of engine.

• Geomechanics and Engineering
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• 제7권2호
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• pp.201-212
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• 2014

Due to the sea-crossing bridge span is generally large and main pier pile foundations are located in deep water and carry large vertical load, sea-crossing bridge main pier pile foundations bearing mechanism and load deformation characteristics are still vague. Authors studied the vertical bearing properties of sea-crossing bridge main pier pile foundations through pilot load tests. Large tonnage load test of Qingdao Bay Bridge main pier pile program is designed by using per-stressed technique to optimize the design of anchor pile reaction beam system. Test results show that the design is feasible and effective. This method can directly test bearing capacity of main pier pile foundations, and analysis bearing behaviors from test results of sensors which embedded in the pile. Through test study the vertical bearing properties of main pier pile foundation and compared with the generally short pile, author summarized the main pier pile foundations vertical bearing capacity and the main problem of design and construction which need to pay attention, and provide a reliable basis and experience for sea-crossing bridge main pier pile foundations design and construction.

• 한국자동차공학회논문집
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• 제10권3호
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• pp.44-50
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• 2002

The connecting rod big-end bearing is one of the most heavily loaded components of the lubrication system of high-speed combustion engines. The supply oil flow has to pass to the main bearing and the rotating crankshaft before entering the connecting rod bearing. It is common knowledge that the centrifugal forces due to the crankshaft rotation influence the oil flow to connecting rod bearing through the oil supply bore, especially, when the oil supply system to the connecting rod bearing has a 180$^{\circ}$circumferential groove via a single drilling in the crankshaft. In this case, it should be confirmed that the groove oil pressure in the main bearing is sufficient to overcome these centrifugal forces. For the purpose, the dynamic oil pressure before entering oil supply bore to the connecting rod bearing was measured instead of averaged oil pressure in main gallery. Experimental test results show that the dynamic oil pressure in the oil groove was more useful than that of main gallery. And it was also found that the oil pressure fluctuation in the groove was sensitively affected by the reduction of the main bearing clearance.

• 한국생산제조학회지
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• 제7권1호
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• pp.119-119
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• 1998

The purpose of this study is to investigate the effects of operation factors of a typical main spindle system on the efficiency of machine tool. In this study. both static and dynamic analysis of typical main spindle system of the machine tool are performed using a finite element method. These finite element results are then used to predict the bearing stiffness. the amount of heat generation as well as the bearing life in the spindle system. Effects of material type of ball-bearing. bearing-lubricant type and main spindle bearing preload are examined.

• 한국생산제조학회지
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• 제24권3호
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• pp.278-286
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• 2015

The effects of the main bearing stiffness combined with vertical non-torque force on the input load and shaft deflection of a gearbox were investigated for the three-point suspension drive train of a wind turbine. A finite element analysis model for the drive train was studied experimentally, and its applicability to the present study was verified. The results show that, as the main bearing stiffness is increased, the input load of the gearbox decreases, whereas the input shaft deflection increases. The stiffness component for the pitch moment has the largest influence on the gearbox input load. Although the gearbox life increases at a higher main bearing stiffness, the economic efficiency and durability of the entire drive train system should also be considered in the selection of the main bearing stiffness.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1997년도 추계학술대회 논문집
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• pp.94-100
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• 1997

The purpose of this study is to investigate the effects of operation factors of a typical main spindle system on its efficiency. Among important factors, material type of ball-bearing, bearing-lubricant type and main spindle bearing preload are taken into considered.

• 대한기계학회논문집 C: 기술과 교육
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• 제1권1호
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• pp.129-138
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• 2013

화력발전소의 보일러를 일정한 화력으로 가동하기 위해서는 일정한 통풍량을 유지시켜야 한다. Main Bearing Assembly Unit 일정한 통풍량을 유지시키기 위하여 Fan을 회전시킨다. 그러나 점차 발전량이 많아지는 반면에 발전을 위하여 투입되는 석탄의 질은 초기의 보일러 설계 기준보다 나빠지고 있다. 특히 원가절감의 일환으로 또는 자원의 고갈로 인한 고급품질의 석탄 확보가 어려움으로 인하여 점차 낮은 질의 석탄이 투입되고 있다. 이로 인하여 초기 설계시의 Main Bearing Assembly의 수명보다 약 절반의 수명인 2~3년의 주기로 Main Bearing Assembly의 정비교체가 요구되고 있다. 본 연구에서는 Main Bearing Assembly Unit의 역설계 해석을 통해서 수명단축의 원인을 분석하고 초기 목표 수명을 가질 수 있도록 새로운 시스템으로 개선하여 개발하고자 한다.

• Tribology and Lubricants
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• 제18권2호
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• pp.105-108
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• 2002

Specially designed grooved journal bearings are installed in the main coolant pump for SMART (System-integrated Modular Advanced ReacTor) to support radial load on the rotating shaft. The canned motor type main coolant pumps are arranged vertically on the reactor vessel and filled with circulating primary coolant which is pure water. The main coolant pump bearings are lubricated with this coolant without any other external lubricant supply. Because lubricating condition is too severe for this bearing to generate proper hydrodynamic film, investigation of lubrication characteristics of the journal bearing is important to satisfy life constraint of whole pump system, and the results will be applied to the analysis of dynamic characteristics of the shaft system. The bearing is made of silicon graphite which has self$.$lubricating effect. A lubrication analysis method is proposed for this vertically grooved journal bearing in the main coolant pump of SMART, and lubricational characteristics of the bearings are examined in this paper.

• Tribology and Lubricants
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• 제26권4호
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• pp.240-245
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• 2010

This paper describes the influence on engine main bearing behavior of the oil film when the fuel is diluted on a diesel engine equipped with DPF system. Oil film pressure and the thickness is calculated in accordance to the fuel dilution. The calculation is based on the numerical analysis of the engine main bearing. As a result, the engine oil viscosity decreased as the fuel dilution increased. This led the increment of the maximum oil thickness pressure. Verification of the minimum oil film thickness settlement by the engine gas pressure and the fuel dilution was confirmed. Destruction possibility of the engine main bearing was foreseen when the engine speed was 2000 rpm with the fuel dilution 15% and the 5W40 engine oil.