• 제목/요약/키워드: Bearing Support Stiffness

검색결과 71건 처리시간 0.019초

A hybrid method for dynamic stiffness identification of bearing joint of high speed spindles

  • Zhao, Yongsheng;Zhang, Bingbing;An, Guoping;Liu, Zhifeng;Cai, Ligang
    • Structural Engineering and Mechanics
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    • 제57권1호
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    • pp.141-159
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    • 2016
  • Bearing joint dynamic parameter identification is crucial in modeling the high speed spindles for machining centers used to predict the stability and natural frequencies of high speed spindles. In this paper, a hybrid method is proposed to identify the dynamic stiffness of bearing joint for the high speed spindles. The hybrid method refers to the analytical approach and experimental method. The support stiffness of spindle shaft can be obtained by adopting receptance coupling substructure analysis method, which consists of series connected bearing and joint stiffness. The bearing stiffness is calculated based on the Hertz contact theory. According to the proposed series stiffness equation, the stiffness of bearing joint can be separated from the composite stiffness. Then, one can obtain the bearing joint stiffness fitting formulas and its variation law under different preload. An experimental set-up with variable preload spindle is developed and the experiment is provided for the validation of presented bearing joint stiffness identification method. The results show that the bearing joint significantly cuts down the support stiffness of the spindles, which can seriously affects the dynamic characteristic of the high speed spindles.

교반기용 임펠러가 달린 축의 베어링 지지점에 따른 진동특성 (Vibration Characteristics of Impeller Shaft for Mixing Machine According to the Positions of a Bearing Support)

  • 홍도관;안찬우;백황순;최석창;박일수
    • 한국기계가공학회지
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    • 제8권3호
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    • pp.68-73
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    • 2009
  • This paper deals with the dynamic characteristics of the impeller shaft model which is the most important part in developing the resin mixing machine. The can is rotating by air motor in mixing machine. Then the end of shaft is fixed. The bearing support is to increase the fundamental natural frequency. The natural frequency analysis using finite element analysis software are performed on the imported commercial impeller shaft model. This paper presents calculated bearing stiffness of Soda, Harris and modified Harris formula considering contact angle according to bearing supported position. The most important fundamental natural frequency of the impeller shaft except bearing support is around 13.932 Hz. This paper presents one bearing and two bearings support position to maximize the 1st natural frequency. The maximized fundamental natural frequency is around 48.843 Hz in one bearing support and 55.52 Hz in two bearings support.

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지지구조물을 고려한 로터-베어링 시스템의 동 특성해석 (Dynamic Characteristics Analysis of Rotor-Bearing System with Support Structures)

  • 박성훈;오택열
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 1997년도 추계학술대회 논문집
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    • pp.547-550
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    • 1997
  • The dynamic behavior of rotor-bearing system has been investigated using finite element method. A procedure is presented for dynamic modeling of rotor-bearing system which consist of shaft elements, rigid disk, flexible bearing and support structures. A finite element model including the effects of rotary inertia, shear deformation, gyroscopic moments is developed. Linear stiffness and damping coefficient are calculated for 3 lobe sleeve bearing. The whirl frequency, mode shape, stability and unbalance response of rotor system included effect of bearing coefficient and support structures are calculated.

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풍력발전기용 3점 지지 드라이브 트레인의 지지 강성이 기어박스 입력하중에 미치는 영향 (The Influence of Suspension Stiffness on the Gearbox Input Loads in a 3-Point Suspension Wind Turbine Drive Train)

  • 남주석;남용윤
    • 한국생산제조학회지
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    • 제24권5호
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    • pp.514-520
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    • 2015
  • The effects of suspension stiffness on the reaction load of the gearbox suspension for a three-point suspension wind turbine drive train were investigated by finite element analysis. The reaction forces of the gearbox suspension appear to increase as the gearbox suspension stiffness increases; however, the main bearing stiffness has a reverse effect on the reaction forces. The influence of the gearbox suspension stiffness is greater than that of the main bearing. Since the suspensions must provide the gearbox with proper support, it is not practical to use soft gearbox suspension for small reaction forces. It is more feasible to use stiff main bearings. As a guideline for the main bearing stiffness in the present study, we propose a relative stiffness of 100-150% of the reference.

유막 저어널 베어링이 회전체에 미치는 진동 특성에 관한 연구 (A Study on the Vibration Characteristics of Rotor System with Fluid Film Bearing)

  • 박성환;오택열
    • 한국정밀공학회지
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    • 제19권10호
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    • pp.37-44
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    • 2002
  • The dynamic behavior of rotor-bearing system has been investigated using finite element method. A procedure is presented for dynamic modeling of rotor-bearing system which consists of shaft elements, rigid disk, flexible bearing and support structure. A finite element model including the effects of rotary inertia, shear deformation, gyroscopic moments is developed. Linear stiffness and damping coefficients are calculated for 2 lobe sleeve bearing. The whirl frequency, mode shape, stability and unbalance response of rotor system including effects of bearing coefficient and support structures are calculated.

2 열 원주 그루브 급기 원추형 공기베어링의 해석 (Analysis of the Conical Air Bearings with two Circumferential Grooves)

  • 김성균;박상신;김우정;한동철
    • 한국윤활학회:학술대회논문집
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    • 한국윤활학회 1993년도 제18회 학술대회 초록집
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    • pp.51-56
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    • 1993
  • The conical bearing can be used to support the radial and thrust load simultaneously. Two circumferential grooves with discrete hole restrictions are made on the bearing surface in order to increase stiffness. In this paper, the dynamic characteristics of this type of bearings are calculated such as stiffness and champing coefficients. As a results of theoretical analysis, it is verified that there exist the groove depth and distance between two grooves which produce the maximum stiffness at the given bearing dimensions.

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2열 원주 그루브 급기 원추형 공기베어링의 해석 (Analysis of the Conical Air Bearings with two Circumferential Grooves)

  • 김성균;박상신;한동철
    • Tribology and Lubricants
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    • 제10권1호
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    • pp.56-61
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    • 1994
  • The conical bearing can be used to support the radial and thrust load simultaneously. Two circumferential grooves with discrete hole restrictions are made on the bearing surface in order to increase stiffness. In this paper, the dynamic characteristics of this type of bearings are calculated such as stiffness and damping coefficients. As a results of theoretical analysis, it is verified that there exist the groove depth and distance between two grooves which produce the maximum stiffness at the given bearing dimensions.

초고속 구동축의 지지 조건에 따른 안정성 분석 (Stability Analysis of High-speed Driveshafts under the Variation of the Support Conditions)

  • 신응수
    • 한국생산제조학회지
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    • 제20권1호
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    • pp.40-46
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    • 2011
  • This paper is to investigate the effects of the asymmetrical support stiffness on the stability of a supercritical driveshaft with asymmetrical shaft stiffness and anisotropic bearings. The equations of motion is derived for a system including a rigid disk, a massless flexible asymmetric shaft, anisotropic bearings and a support beam. The Floquet theory is applied to perform the stability analysis with the variation of the support stiffness, the shaft asymmetry, the shaft damping and the shaft speed. The results show that the asymmetric support stiffness is closely related to the stability caused by primary resonance as well as the supercritical operation. First, the stiffness variation can stabilize the system around primary resonance by weakening the parametric resonance from the shaft asymmetry. Second, it also improve the stability characteristics at a supercritical operation when the support stiffness is not so high relative to the shaft stiffness.

35 kWh급 플라이휠용 초전도 베어링의 댐핑 특성평가 (Damping Properties of a Superconductor Bearing in a 35 kWh Class Superconductor Flywheel Energy Storage System)

  • 박병준;정세용;한상철;한상진;이대화;한영희
    • Progress in Superconductivity
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    • 제14권1호
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    • pp.66-70
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    • 2012
  • Superconductor flywheel energy storage system (SFESs) is an electro-mechanical battery with high energy storage density, long life, and good environmental affinity. SFESs have been developed for application to a regenerative power of train, the storage of distributed power sources such as solar and wind power, and a power quality improvement. As superconductor bearing is completely passive, it is not necessary to control a system elaborately but accurate analysis in mechanical properties of the HTS bearing is very important for application to SFESs. Stiffness and damping properties are the main index for evaluation the capacity of HTS bearings and make it possible to adjust rotordynamic properties while operating the rotor-bearing system. The superconductor bearing consists of a stator containing single grain YBCO bulks, a ring-type permanent magnet rotor with a strong magnetic field that can reach the bulk surface, and a bearing support for assembly to SFESs frame. In this study, we investigated the stiffness and damping properties of superconductor bearings in 35 kWh SFESs. Finally, we found that 35 kWh superconductor bearing has uniform stiffness properties depend on the various orientations of rotor vibration. We discovered total damping coefficient of superconductor bearing is affected by not only magnetic damping in superconductor bulk but also external damping in bearing support. From the results, it is confirmed that the conducted evaluation can considerably improve energy storage efficiency of the SFESs, and these results can be used for the optimal capacity of superconductor bearings of the SFESs.

수명과 강성을 고려한 자동차용 휠 베어링의 설계 최적화 (Design Optimization for Automotive Wheel Bearings Considering Life and Stiffness)

  • 이승표
    • Tribology and Lubricants
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    • 제39권3호
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    • pp.94-101
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    • 2023
  • Automotive wheel bearings are a critical component of vehicles that support their weight and facilitate rotation. Life and stiffness are significant performance characteristics of wheel bearings. Designing wheel bearings involves finding optimal design variables that satisfy both performances. CO2 emission reduction and fuel efficiency regulations attribute to the recent increase in design requirements for lightweight and compact automotive parts while maintaining performance. However, achieving a design that maintains performance while reducing weight poses challenges, as performance and weight are generally inversely proportional. In this study, we perform design optimization of automotive wheel bearings considering life and stiffness. We develop a program that calculates the basic rated life and modified rated life based on international standards for evaluating the life of wheel bearings. We develop a regression equation using regression analysis to address the time-consuming stiffness analysis during repetitive analysis. We perform ANOVA and main effect analyses to understand the statistical characteristics of the developed regression equation. Furthermore, we verify its reliability by comparing the predicted and test results. We perform design optimization using the developed life prediction program, stiffness regression equation and weight regression equation. We select bearing specifications and geometry as design variables, weight as the cost function, and life and stiffness as constraints. Through design optimization, we investigate the influence of design variables on the cost function and constraints by comparing the initial and optimal design values.