• 제목/요약/키워드: number of rolling elements

검색결과 8건 처리시간 0.024초

EHL Analysis of Rolling Bearings Considering the Effect of the Number of Rolling Elements and the Shaft Load

  • Hong, Sung-Ho;Kim, Kyung-Woong
    • KSTLE International Journal
    • /
    • 제10권1_2호
    • /
    • pp.17-22
    • /
    • 2009
  • The numerical analysis of elastohydrodynamic lubrication for the ball and roller bearings is performed in order to study the effect of the number of rolling elements and the shaft load on the minimum film thickness. A finite difference method and the Newton-Raphson method are used in the analysis. For a given shaft load, the maximum load of rolling element is determined along with the number of rolling elements. And then the minimum film thickness is calculated for several rolling bearings. The shape of film thickness and the pressure distribution are also studied.

Lead Screw 공정 설계를 위한 전조 해석 (Thread Rolling Analysis for Lead Screw Process Design)

  • 신명수;차성훈;김종봉;김종호;나승우
    • Elastomers and Composites
    • /
    • 제44권4호
    • /
    • pp.391-396
    • /
    • 2009
  • 본 연구에서는 전조공정의 수치해석을 수행하였다. 해석을 이용한 공정 인자 설계에 앞서서, 효율적이고 신뢰성 있는 해석을 위한 해석 조건에 대하여 연구를 수행하였다. 치형의 개수와 요소의 수에 대한 해석 결과를 바탕으로 해석의 정도를 보장하고 효율적으로 해석을 수행할 수 있는 조건을 설정하였다. 그리고, 프랭크 각도와 치형의 끝단부 라운드 등의 금형의 형상과 성형 온도가 유효 응력, 유효 변형율, 전조력, 그리고 크랙 발생에 미치는 영향을 알아보았다. 해석은 DEFORM-3D를 이용하여 수행하였다. 프랭크 각도와 치형의 끝단 부 라운드는 전조력에 영향을 미치는 것을 확인할 수 있었으며, 성형 온도 조건에 따라서 유효 변형률과 전조력, 그리고 크랙을 예상 할 수 있었다.

직선운동베어링 성능평가방법의 표준화 및 내구성 시험에 관한 연구 (A Study on the Fatigue Test and Performance Evaluation for Linear Motion Rolling Bearing)

  • 김태범;김동길;이상조;김익수;이위로;이동규
    • 한국정밀공학회:학술대회논문집
    • /
    • 한국정밀공학회 2003년도 춘계학술대회 논문집
    • /
    • pp.1270-1274
    • /
    • 2003
  • The objective of this paper is to introduce the standard of evaluation methods and fatigue test for linear motion rolling bearing. In particular, attention well be given to the list of evaluation and fatigue results in this paper. The life of a linear motion rolling bearing is given by the length of distance covered between the connection parts before the first evidence of fatigue develops in the material of one of the raceways of rolling elements. The main factors that contribute to fatigue failures include: Number of load cycles experienced; Range of stress experienced in each load cycle; Mean stress experienced in each toad cycle; Presence of local stress concentrations.

  • PDF

멀티 스케일 모델을 적용한 선재 공정의 미세결함 형상 변화 예측 (Prediction of defect shape change using multiple scale modeling during wire rod rolling process)

  • 곽은정;강경필;이경훈;손일헌
    • 한국소성가공학회:학술대회논문집
    • /
    • 한국소성가공학회 2009년도 추계학술대회 논문집
    • /
    • pp.169-172
    • /
    • 2009
  • Multiple scale modeling has been applied to predict defect shape change during the wire rod rolling process. The size difference between bloom and defect prevent using usual FEM approaches due to the enormous number of elements required to depict the defect. The newly developed multiple scale model can visualize defect shape changes during the multi stands rolling process. The defect positioned at the top and side of bloom are smoothed out but the one at the middle evolved as folding or remained as crack. This approach can be used for defect control with roll shape design and initial bloom shape.

  • PDF

자동차 변속기용 깊은 홈 볼 베어링의 내구수명 향상 (Improving the Endurance Life of Deep Groove Ball Bearings for Automotive Transmission)

  • 백혜연;편정민;이대용;박태조
    • Tribology and Lubricants
    • /
    • 제31권6호
    • /
    • pp.281-286
    • /
    • 2015
  • Automotive transmission systems are assembled with a large number of gears and shafts, and rolling bearings are used to ensure their smooth operation. Gear oil in the gear box contains solid particles such as wear debris from contacting gears and metallic chips. This particle-enriched lubricating oil can cause premature failure of the rolling bearings. Research aimed at improving the service life of these rolling bearings has been confined mainly to design and lubrication of the inner/outer rings and the rolling elements. In this paper, we redesigned the shape of the cage pocket of a deep groove ball bearing to reduce the premature failure due to particle contamination. Test bearings are assembled with this new cage design containing a hole punched in the cage pocket. Endurance tests are carried out using the contaminated lubricating oil with miracle grid as hard particle. The duration and damaged bearing component shapes are compared for two different cages. The B10 life of bearing with new cage is increased by about 66% compared to the conventional cage. This is because the hard particles can be easily discharged through the pocket hole without staying for a long time in the lubrication regions. This greatly decreases abrasive wear and dents on the highly stressed ball bearing surfaces. Therefore, the cage design of this study, containing a pocket hole, can significantly delay the premature failure of rolling bearings and improve the endurance life.

공형압연 공정에서 소재 표면흠 발생억제를 위한 패스 스케줄 설계 (Pass Schedule Design to Inhibit Surface Cracks Generation on Workpiece in Groove Rolling Process)

  • 나두현;이영석
    • 대한기계학회논문집A
    • /
    • 제34권10호
    • /
    • pp.1443-1453
    • /
    • 2010
  • 본 연구에서는 소재 표면흠 발생을 억제하기 위해 유한요소법을 사용하여 세아베스틸 선재 조압연 라인 공정을 모사하였다. 선재 조업연 라인의 2 번 공형을 설계하였고 이 공형을 압연 라인에 적용하였다. 또한 유한요소법을 사용하여 3 번, 4 번 공형 롤 갭이 변경된 새로운 패스 스케줄을 제안하였다. 본 연구에서는 전단응력비에 의존적인 전단파괴 모델을 사용하였고 소재의 손상된 요소 수를 비교하였다. 손상된 요소는 표면흠을 의미한다. 결과적으로 2 번 공형이 변경된 후 불량률은 이전 공형보다 1.43% 감소되었다. 그리고 새로운 패스 스케줄의 손상된 요소 수는 현재 패스 스케줄보다 37.6% 감소되었다.

조망거리에 따른 농촌경관의 농촌다움 평가에 관한 연구 (A Study on Evaluation of the Rurality by the Distance of View)

  • 신민지;신지훈
    • 농촌계획
    • /
    • 제21권2호
    • /
    • pp.63-77
    • /
    • 2015
  • Improve the rural views of the Government and the municipalities with the intention of rural landscape planning. However, rural scenery evaluation of landscape types and element categories, landscape scenes, such as the valuation of resources selected, form a coherent system and ecological point of view is not only a Visual perspective of evaluation, or evaluation is made. This study evaluates the rural landscape through the rural landscape for rurality is implemented can explain the image. Rural amenity 100 represented the rural landscape in rurality with photos of photos, and scenes, photos, location-based rural Vista rurality landscapes drawn components. Selected landscape photography scenic landscapes in the u.s. survey and image vocabularies through surveys is representative of the landscape in rurality of each Vista location-specific photos and images began extracted factors. As a result, the Distant view is a town and village in the rolling hills of the surrounding environment is an image behind the Vista Skyline, Farmland Rural village forests, Behind the hills, Individual housing roof, Housing arrangement, The number of household includes landscape components. Factor analysis 'openness', 'intimacy', 'activity', 'complexity', 'safety' was down to five factors, such as a description of the overall factors that force was 66.45 percent. Middle distance view is close to being out of town houses and village environment, an image in the skyline hills Vista, farmlands, village forests, rolling hills, behind the scenes of the housing component of the neck, the sperm will honor an individual factor analysis results are 'intimacy', 'safety', 'openness', 'specificity', 'complexity' five factors the whole description of the capacity factors compared to 67.24 percent. Close-range view is mainly in Vista village embraced the individual elements and an image of a harmonious location in the surroundings of the sperm, individual houses, fences, gates, courtyard, Garden, garage, agricultural facilities, including, but not limited to, factors assay but an 'intimacy', 'complexity', 'safety', 'activity', 'openness' five factors, such as a description of the overall factors that force was 65.29%. This research seeks to determine the extent to which rurality of rural landscape Vista by location attributes and elements and representative officer in photo selection and rurality to extract the image. To date, followed by a comprehensive study, which was presented through the readjustment could not overlook the Visual elements. The future rural development officer for the evaluation of rural landscape classification and quantitative and objective assessment will have to come up with ways to do.

API X80 라인파이프강의 용접열영향부 충격인성에 미치는 복합산화물의 영향 (Effects of Complex Oxides on HAZ Toughness of Three API X80 Linepipe Steels)

  • 신상용;오경식;강기봉;이성학
    • 대한금속재료학회지
    • /
    • 제46권4호
    • /
    • pp.199-208
    • /
    • 2008
  • This study is concerned with effects of complex oxides on Charpy impact toughness of heat affected zone (HAZ) of API X80 linepipe steels. Three kinds of steels were fabricated by varying alloying elements such as Ti, Al, and Mg and hot-rolling conditions to form complex oxides, and their microstructures and Charpy impact properties were investigated. The number of complex oxides present in the steel containing excess Ti, Al, and Mg was twice larger than that in the conventional steels, while their size ranged from 1 to $3{\mu}m$ in the three steels. After the HAZ simulation test, the steel containing a number of oxides contained about 20 vol.% of acicular ferrite in the simulated HAZ, together with bainitic ferrite and martensite, whereas the HAZ microstructure of the conventional steels consisted of bainitic ferrite and martensite with a small amount of acicular ferrite. This formation of acicular ferrite in the oxide-containing steel was associated with the nucleation of acicular ferrite at complex oxides, thereby leading to the great (five times or more) improvement of Charpy impact toughness over the conventional steels.