Dynamic characteristics of a hard disk drive spindle system due to imperfect shaft roundness

K. Y. Koak, H. W. Kim, K. M. Jung, Gunhee Jang

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

This paper proposes a modified Reynolds equation for the coupled journal and thrust fluid dynamic bearings (FDBs) to include variable film thickness due to imperfect roundness of a rotating shaft. A finite element method is used to solve the modified Reynolds equation to calculate the pressure. Reaction force, moment, and friction torque of FDBs are calculated by integrating the pressure and shear stress along the fluid film. The dynamic behavior of a hard disk drive (HDD) spindle system is investigated by solving the equations of motion with six degrees of freedom using the RungeKutta method. This research shows that the imperfect roundness of the shaft increases the nonlinearity of FDBs. Imperfect roundness of the shaft generates harmonics of the groove number ± 1 in the bearing reaction force and the displacement of the HDD spindle system even in the case of stationary grooved FDBs.

Original languageEnglish
Article number5297539
Pages (from-to)5148-5151
Number of pages4
JournalIEEE Transactions on Magnetics
Volume45
Issue number11
DOIs
StatePublished - 2009 Nov 1

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Bearings (structural)
Hard disk storage
Fluid dynamics
Reynolds equation
Equations of motion
Film thickness
Shear stress
Torque
Friction
Finite element method
Fluids

Keywords

  • Dynamic behavior
  • Fluid dynamic bearings (FDBs)
  • Groove
  • Reynolds equation
  • Roundness

Cite this

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abstract = "This paper proposes a modified Reynolds equation for the coupled journal and thrust fluid dynamic bearings (FDBs) to include variable film thickness due to imperfect roundness of a rotating shaft. A finite element method is used to solve the modified Reynolds equation to calculate the pressure. Reaction force, moment, and friction torque of FDBs are calculated by integrating the pressure and shear stress along the fluid film. The dynamic behavior of a hard disk drive (HDD) spindle system is investigated by solving the equations of motion with six degrees of freedom using the RungeKutta method. This research shows that the imperfect roundness of the shaft increases the nonlinearity of FDBs. Imperfect roundness of the shaft generates harmonics of the groove number ± 1 in the bearing reaction force and the displacement of the HDD spindle system even in the case of stationary grooved FDBs.",
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Dynamic characteristics of a hard disk drive spindle system due to imperfect shaft roundness. / Koak, K. Y.; Kim, H. W.; Jung, K. M.; Jang, Gunhee.

In: IEEE Transactions on Magnetics, Vol. 45, No. 11, 5297539, 01.11.2009, p. 5148-5151.

Research output: Contribution to journalArticle

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AU - Koak, K. Y.

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