• 제목/요약/키워드: Bearing error

검색결과 289건 처리시간 0.029초

소음/진동을 고려한 발전설비용 감속기 개발 (Development of Reducer for Generating Facility of Electric Power for Low Noise/vibration)

  • 이형우;박철우
    • 한국정밀공학회지
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    • 제25권11호
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    • pp.73-82
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    • 2008
  • A dynamic model of reducer for generating facility of electric pourer having bevel gear pair and planetary gear train is developed by lumped method. The model accounts for the shaft and bearing flexibilities, gyroscopic effects and the force couplings among the transverse and torsion motions due to gearing. Vibration/noise analysis as well as strength of bevel gear pair and planetary gear train are considered. Exciting forces of high reducer for generating facility of electric power areconsidered as the mass unbalance of the rotors, misalignment and a function of gear transmission error. A Campbell diagram, in which the excitation sources caused by the mass unbalance of the rotors, misalignment and the transmitted errors of the gearing are considered, shows that, at the operating speed, there are not critical speed.

영구자석형 직류전동기 축계의 유한요소모델 개선과 진동해석 (Finite Element Model Updating and Vibration Analysis of PMDC Motor Rotor System)

  • 김용한;하종룡;이재갑;김선화;양보석
    • 동력기계공학회지
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    • 제11권1호
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    • pp.20-27
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    • 2007
  • In this paper, finite element modeling was performed for vibration analysis of a rotor system installed in sunroof motor, and analysis process was developed for natural frequency and unbalance response analysis. At the same time, to reduce analysis modeling error caused by the difference between analysis and measured values, finite element model updating was conducted using an optimization algorithm, i.e. hybrid genetic algorithm and simulated annealing (HGASA) method. For this end experimental modal test was carried out and by using the measured frequency response function (FRF), model updating was performed considering both cases where core coil was removed and included. And acceptable result was obtained. Also, dynamic property coefficient of bush bearing which influences vibration response of the rotor system was estimated.

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2차원적 음원추적에 관한 연구 II (A Study on 2-Dimensional Sound Source Tracking System II)

  • 문성배;전승환
    • 한국항해학회지
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    • 제22권4호
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    • pp.31-36
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    • 1998
  • The whistle is a very important information source for the safety navigation under foggy weather. But navigator has no concern about this, because it must be achived by human hearing sense and considered as a vague signal. If the range and relative bearing of signal source can be detected automatically, it would be very useful system for preventing marine casualties making a lot of economic loss and environment pollution. Before the algorithm of 2-dimensional sound source tracking system was reported. This paper describes the method that can obtain the time lag between three signals and the theory of cross-correlation analysis and subtraction method for cauculating the time lag by using the digital signal data sequences. And a series of experiments were carried out for various position of sound source in the range from 200cm to 530cm. As a result, we have recognized that sound source tracking system is possible to the sea field with improvement of position error.

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자기베어링용 유도형 위치 센서의 성능에 미치는 와전류와 히스테레시스의 영향 (The Effects of Eddy Currents and Hysteresis on the Performance of Inductive Position Sensor for Magnetic Bearings)

  • 노명규;정민경
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2001년도 춘계학술대회논문집B
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    • pp.36-41
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    • 2001
  • The performance of an inductive position sensor is described by the accuracy and the dynamic characteristics of the sensor. Both of these performance indices are affected by magnetic hysteresis and eddy currents. In this paper, a model of an inductive sensor is presented. This model includes the effects of hysteresis and eddy currents. Computer simulation shows that the sensitivity of the sensor is greatly affected by hysteresis and eddy currents. Repeability error increases with hysteresis and eddy currents effects. Results also show that eddy currents influence more on the sensor performance than hysteresis does. To reduce the effects of hysteresis and eddy currents, the sensor should be made out of thin laminations with high resistivity.

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고속절단기의 진동저감을 위한 회전체역학 해석 (Rotordynamic Analysis for Vibration Reduction of a High Speed Cutter)

  • 서준호;백경원;최연선
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2004년도 추계학술대회논문집
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    • pp.1056-1061
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    • 2004
  • The vibration of rotor systems is caused by various factors, such as misalignment, unbalance, gear meshing, error of assembly, etc. Modal test and TDA/ODS analysis were done. The dynamic analysis of the armature was done with SAMCEF which is a commercial software for finite element and kinematic analysis. The transient response of the armature is calculated by the SAMCEF with the consideration of magnetic force and bearing stiffness, which are the essential elements for the design of high speed cutter. Main frequency of the vibration is due to the unbalance of the armature. The FEM analysis model considering unbalance and the high speed cutter have same vibration properties. The vibration sources of the high speed cutter is proved to be unbalance.

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보수전과 후의 홍예교의 동적특성과 구조성능에 대한 해석연구 (Analytical Study of a Historic Stone Arch Bridge After Retrofit to Evaluate Dynamic Characteristics and Structural Behavior)

  • 이가윤;이성민;이기학
    • 한국공간구조학회논문집
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    • 제20권4호
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    • pp.177-184
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    • 2020
  • This study evaluates safety assessment before and after repair of Seonamsa temple seungseon bridge, which refer to the representative Hongye bridge in Korea. In this approach natural frequency of the structure were considered in the modeling procedure. Trial & error method is applied to obtain the approximate natural frequency before and after retrofit construction. Stiffness of the actual structure was examined to account for the dynamic characteristics of Hongye bridge measured in the field and adjusting parameters in computer modeling. The safety and usability of the stone structure in terms of load bearing capacity and displacement were examined.

인공 신경망 이론을 이용한 말뚝의 극한지지력 해석(I)-이론 (Analysis of Ultimate Bearing Capacity of Piles Using Artificial Neural Networks Theory (I) -Theory)

  • 이정학;이인모
    • 한국지반공학회지:지반
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    • 제10권4호
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    • pp.17-28
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    • 1994
  • 인간의 두뇌는 분산 병렬 처리에 효과적이라는 사실에 근거하여 인공 신경망이론이 개발되었으며, 과학의 여러 분야에서 성공적으로 적용되어지고 있다. 본 연구에서는 인공 신경망 이론의 학습방법 중 하나인 오차 역전파 학습 알고리즘을 모형 말뚝의 극한지지력 예측에 적용하여, 이 이론이 말뚝의 극한지지력의 합리적인 산정방법으로 적용될 수 있는지의 가능성을 검토하였다. 이러한 시스템의 타당성 검토를 위하여 총 28개의 모형 말뚝재하시헙 결과를 이용하였으며, 그 중에서 9, 14, 21개의 자료를 네트워크 학습에 이용하여 나머지 자료의 예측 가능 정도를 분석하여 보았다. 개발된 시스템은 14개 이상의 학습자료에 대하여 모형 말뚝재하시험의 결과와 잘 맞는 것으로 나타났다. 이와같은 결과들을 종합하여 보건데 신경망 이론이 말뚝의 극한지지력 예측 문제에 적용될 수 있는 가능성을 보여 주었다.

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롤러베어링 구조형 주축 회전체의 언밸런스 변동과 절삭표면상태 연관성에 관한 연구 (Correlation between Unbalance Variation and Cutting Surface Condition of Roller Bearing-Structured Main Spindles)

  • 하정웅;박동희;박황기;전승민;홍진표;윤상환;박종규
    • 한국기계가공학회지
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    • 제19권9호
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    • pp.107-115
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    • 2020
  • The rotation accuracy of the main spindle that determines the accuracy of CNC machine tools is closely related to the quality of production because it directly affects the shape error and surface roughness of the workpiece. Therefore, the main spindle requires high rotation accuracy, rigidity, and rotation technology. This rotation accuracy is greatly affected by the bearing, center alignment between rotating parts, assembly tolerance, and unbalance of the rotation mass. In this study, the effects of the unbalance of the rotation mass of the main spindle on the rotation accuracy were investigated experimentally. In particular, we tried to study the technical reasons for improving the unbalance of the main spindle and maintaining the rotation accuracy as we verified the correlation between the vibration characteristics of CNC machine tools due to the specifically set unbalance amount and the surface roughness of the workpiece.

풍화암에 근입된 현장타설말뚝의 외삽 파괴하중 신뢰성 분석 (Reliability Evaluation of Extrapolated Failure Load of Drilled Shafts Embedded in Weathered Rock)

  • 정성준;이상인;전종우;김명모
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2009년도 세계 도시지반공학 심포지엄
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    • pp.993-1000
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    • 2009
  • In general, a drilled shaft embedded in weathered rock has a large load bearing capacity. Therefore, most of the load tests are performed only up to the load level that confirms the pile design load capacity, and stopped much before the failure load of the pile is attained. If a reliable failure load value can be extracted from the premature load test data, it will be possible to greatly improve economic efficiency as well as pile design quality. The main purpose of this study is to propose a standard for judging the reliability of the failure load of piles that is obtained from extrapolated load test data. To this aim, eleven static load test data of load-displacement curves were obtained from testing of piles to their failures from 3 different field sites. For each load-displacement curve, loading was assumed as 25%, 50%, 60%, 70%, 80%, and 90% of the actual pile bearing capacity. The limited known data were then extrapolated using the hyperbolic function, and the failure load was re-determined for each extrapolated data by the ASCE 20-96 method (1997). Statistical analysis was performed on the reliability of the re-evaluated failure loads. The results showed that if the ratio of the maximum-available displacement to the failure-load displacement exceeds 0.6, the extrapolated failure load may be regarded as reliable, having less than a conservative 20% error on average. The applicability of the proposed standard of judgment was also verified with static load test data of driven piles.

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지구 곡률이 고려된 LOB를 이용하는 NLSE 기반의 고정형 신호원 위치추정 (Stationary Emitter Geolocation Based on NLSE Using LOBs Considering the Earth's Curvature)

  • 박병구;김상원;안재민;김영민
    • 한국통신학회논문지
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    • 제42권3호
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    • pp.661-672
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    • 2017
  • 본 논문은 지구를 구체(Sphere)로 모델링하고, 좌표계 변환 없이 위경도 좌표계에서 지구 곡률이 고려된 곡선형태의 신호방향선(Line Of Bearing, LOB)을 이용하여 비선형 최소제곱법(Nonlinear Least Squared Estimator, NLSE)으로 고정형 신호원의 위치를 추정하는 방법을 소개한다. 그리고 추가적으로 지구를 타원체(Ellipsoid)로 모델링하여 위치추정성능을 개선하는 방법을 제안한다. 모의실험을 통해 지구 곡률이 고려된 곡선 LOB를 이용하는 NLSE 방법이 기존 삼각측량법(Triangulation Method) 대비 우수한 위치추정 성능을 가짐을 보이고 타원체 모델을 이용하여 위치추정성능을 개선함을 보인다.