• Title/Summary/Keyword: Coupled Journal and Thrust Bearing

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Finite Element Analysis of a Coupled Hydrodynamic Journal and Thrust Bearing in a Computer Hard Disk Drive (컴퓨터 하드디스크 드라이브에 사용되는 저널과 스러스트가 연성된 유체 동압 베어링의 유한 요소 해석)

  • Kim, Hakwoon;Lee, Sanghoon;Jang, Gunhee
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.15 no.1 s.94
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    • pp.87-95
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    • 2005
  • This paper proposes a method to calculate the characteristics of a coupled hydrodynamic journal and thrust bearing of a HDD spindle motor. The governing equations for the journal and thrust bearings are the two dimensional Reynolds equations in $\theta z$ and $ r\theta$ planes, respectively. Finite element method is appropriately applied to analyze the coupled journal and thrust bearing by satisfying the continuity of mass and pressure at the interface between the journal and thrust bearings. The pressure in a coupled bearing is calculated by applying the Reynolds boundary condition and compared with that by using the Half-Sommerfeld boundary condition. The static characteristics are obtained by integrating the pressure along the fluid film. The flying height of spindle motor is measured to verify the proposed analytical result. This research shows that the proposed method can describe HDB in a HDD system more accurately and realistically than the separate analysis of a journal or thrust bearing.

Finite Element Analysis of a Coupled Hydrodynamic Journal and Thrust Bearing in a Computer Hard Disk Drive (컴퓨터 하드디스크 드라이브에 사용되는 저널과 스러스트가 연성된 유체 동압 베어링의 유한 요소 해석)

  • Kim, Hak-Woon;Lee, Sang-Hoon;Jang, Gun-Hee
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2004.11a
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    • pp.846-852
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    • 2004
  • This paper proposes a method to calculate the characteristics of a coupled hydrodynamic journal and thrust bearing of a HDD spindle motor. The governing equations for the journal and thrust bearings are the two dimensional Reynolds equations in ${\theta}z$ and $r\theta$ planes, respectively. Finite element method is appropriately applied to analyze the coupled journal and thrust bearing by satisfying the continuity of mass and pressure at the interface between the journal and thrust bearings. The pressure in a coupled bearing is calculated by applying the Reynolds boundary condition and compared with that by using the Half-Sommerfeld boundary condition. The static characteristics are obtained by integrating the pressure along the fluid film. The flying height of spindle motor is measured to verify the proposed analytical result. This research shows that the proposed method can describe HDB in a HDD system more accurately and realistically than the separate analysis of a journal or thrust bearing.

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An Analysis of Coupled Oil-lubricated Groove Journal and Thrust Bearings for Spindle Motor (빗살무늬 저널베어링과 스러스트 베어링으로 이루어진 오일윤활 스핀들 모터 베어링 해석)

  • 오상만;임윤철
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 2000.11a
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    • pp.235-242
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    • 2000
  • In this paper, the dynamic characteristics of coupled herringbone groove journal bearings and spiral groove thrust bearings with conical motion were numerically analyzed, The bearing performance characteristics were calculated by the perturbation method and are solved by FDM. Stability of bearing was obtained from the threshold of instability.

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Dynamic Characteristics of a Coupled Journal and Thrust Hydrodynamic Bearing in a HDD Spindle System Due to Groove Location (HDD 스핀들 시스템에 사용되는 저널과 트러스트가 결합된 유체 동압 베어링의 홈 위치에 따른 동특성 해석)

  • 윤진욱;장건희
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2001.11a
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    • pp.304-311
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    • 2001
  • This research numerically analyzes the dynamic characteristics of a coupled journal and thrust hydrodynamic bearing due to its groove location which has the static load due to the weight of a rotor in the axial direction and the dynamic load due to its mass unbalance in the radial direction. The Reynolds equation is transformed to solve a plain member rotating type of journal bearing(PMRJ), a grooved member rotating type of journal bearing (GMRJ), a plain member rotating type of thrust bearing (PMRT) and a grooved member rotating type of thrust bearing (GMRT). FEM is used to solve the Reynolds equations in order to calculate the pressure distribution in a fluid film. Reaction forces and friction torque are obtained by integrating the pressure and shear stress along the fluid film, respectively. Dynamic behaviors, such as whirl radius or floating height of a rotor, are determined by solving its nonlinear equations of motion with the Runge-Kutta method. This research shows that the groove location affects the pressure distribution in the fluid film and consequently the dynamic performance of a HDD spindle system.

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A Study on Fluid-Structure Interaction of a Hydrostatic Thrust Bearing (정압 스러스트 베어링의 유체-구조물 사이의 상호작용에 관한 연구)

  • Kim, Byung-Tak
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.5 no.3
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    • pp.92-98
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    • 2006
  • In this study, the behavior characteristics of a hydrostatic thrust bearing used in hydraulic equipment was analyzed using a commercial finite element program, ADINA. The solid domain was modeled with the fluid domain simultaneously to solve the fully coupled problem, because this is a problem where a fully coupled analysis is needed in order to model the fluid-structure interaction(FSI). The results such as bearing deformation, stress, film thickness and lifting bearing force were obtained through FSI analysis, and then they were compared with the results calculated from the classical method, a single step sequential analysis. It was found that the result difference between two analyses was increased according to the injection pressure. Therefore, in case of high pressure loading, it is desirable to conduct the FSI analysis to examine the deformation characteristics of a hydrostatic slipper bearing.

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Determination of the Dynamic Coefficients of the Coupled Journal and Thrust Bearings by the Perturbation Method (수학적 섭동법을 이용한 저널과 스러스트가 연성된 유체 동압 베어링의 동특성 계수 해석)

  • Lee, Sang-Hoon;Jang, Gun-Hee
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.16 no.7 s.112
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    • pp.746-753
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    • 2006
  • This paper proposes a method to calculate the stiffness and the damping coefficients of the coupled journal and thrust bearings. The Reynolds equations and their perturbation equations are transformed to the finite element equations by considering the continuity of pressure and flow at the interface between bearings. The Reynolds boundary condition is used in the numerical analysis to simulate the cavitation phenomena. The dynamic coefficients of the proposed method are compared with those of the numerical differentiation of the loads with respect to finite displacements and velocities of bearing center. It shows that the proposed method is more accurate and efficient than the differentiation method.

Determination of the Dynamic Coefficients of the Coupled Journal and Thrust Bearings by the Perturbation Method (수학적 섭동법을 이용한 저널과 스러스트가 연성된 유체 동압 베어링의 동특성 계수 해석)

  • Lee, Sang-Hoon;Jang, Gun-Hee
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2006.05a
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    • pp.666-671
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    • 2006
  • This paper proposes a method to calculate the stiffness and the damping coefficients of the coupled journal and thrust bearings. The Reynolds equations and their perturbation equations are transformed to the finite element equations by considering the continuity of pressure and flow at the interface between bearings. The Reynolds boundary condition is used in the numerical analysis to simulate the cavitation phenomena. The dynamic coefficients of the proposed method are compared with those of the numerical differentiation of the loads with respect to finite displacements and velocities of bearing center. It shows that the proposed method is more accurate and efficient than the differentiation method.

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Characteristics of a Coupled Gas Lubricated Bearing for a Scaled-Up Micro Gas Turbine

  • Lee, Yong Bok;Kwak, Hyunduck;Kim, Chang Ho;Jang, Gun Hee
    • KSTLE International Journal
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    • v.1 no.2
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    • pp.107-112
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    • 2000
  • In case of the limitation of Deep RIE fabrication far Micro Gas Turbine, bearing aspect ratio is limited in very small value. The characteristics such as pressure distribution, load capacity and non-linearity of a short bearing of L/D=0.083 and a conventional bearing of L/D=1.0 with coupled boundary effects are investigated for Micro Gas Turbine bearings. The coupled effect was analyzed by mass conservation at coupled end area. The results, increasing load capacity and non-linearity due to the coupled effect of thrust and journal bearing, are obtained and the selection of journal bearing type is discussed.

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Coupled Boundary Effects on a Gas Lubricated Bearing far a Scaled-Up Micro Gas Turbine

  • Hyunduck Kwak;Lee, Yong-Bok;Kim, Chang-Ho;Gunhee Jang
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 2000.11a
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    • pp.243-249
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    • 2000
  • In case of the limitation of Deep RIE fabrication for Micro Gas Turbine, bearing aspect ratio is limited in very small value. The characteristics such as pressure distribution load capacity and non-linearity of a short bearing of L/D=0.083 and a conventional bearing of L/D=1.0 with coupled boundary effects are investigated far Micro Gas Tlubine bearings. The coupled efffect was analyzed by mass conservation at coupled end area. The results, increasing load capacity and non-linearity due to the coupled effect of thrust and journal bearing, are obtained and the selection of journal bearing type is discussed.

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Frictional Loss Analysis of a Reciprocating Compressor with Thrust Ball Bearing (스러스트 볼 베어링이 적용된 왕복동형 압축기의 마찰손실 해석)

  • Kim, Tae-Jong
    • Tribology and Lubricants
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    • v.27 no.2
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    • pp.101-108
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    • 2011
  • In this paper, a study on the frictional losses and dynamic behaviors of a reciprocating compression mechanism used in small refrigeration compressor is performed. In the problem formulation of the compressor dynamics, the viscous frictional force between piston and cylinder wall is considered in order to determine the coupled dynamic behaviors of piston and crankshaft supported on a thrust ball bearing. The solutions of the equations of motion of the reciprocating mechanism along with the time dependent Reynolds equations for the lubricating film between piston and cylinder wall and lubricant films of the journal bearings are obtained simultaneously. The hydrodynamic forces of journal bearings are calculated using finite bearing model and G$\hat{u}$m-bel boundary condition. And, a Newton-Raphson procedure was employed in solving the nonlinear equations of piston and crankshaft with a thrust ball bearing. The results explored the effects of design parameters on the frictional losses and dynamic stability of the compression mechanism.