• Title/Summary/Keyword: Disk bearing

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An Experimental Study on Ram Pressure and THD Performance of Pivoted Pad Thrust Bearing (피봇식 주력베어링의 선단압력과 THD성능에 관한 실험적 연구)

  • 박홍규;김경웅
    • Tribology and Lubricants
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    • v.2 no.1
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    • pp.61-68
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    • 1986
  • Effects of the ram-pressure on the THD-performance of pivoted pad thrust bearings are investigated experimentally. A sector-shaped tilting pad thrust bearing and a rotating disk are used. Temperature distribution on the disk surface as well as on the pad surface, distribution of the pressure generated within the fluid film, and the film thickness are measured continuously in the circumferential direction after thermal equilibrium is established. The ram-pressure is proportional to the mean pressure of oil film and to the rotational speed of the disk and affects the maximum pressure and the pressure distribution. The temperature rise on the mating surface of the disc and the pad, contacting with the oil film, is proportional to to the bearing load and the disk speed. The ram-pressure and the temperature rise on the disk surface are dominant factors that affect the THD-performance of pivoted pad thrust bearings.

Shape Sensitivity Analysis for the Optimal Design of Air Bearing Sliders of Optical Disk Drives (광디스크 드라이브 공기베어링 슬라이더의 최적설계를 위한 형상민감도 해석)

  • Kim, Hyun-Ki;Jang, Hyuk;Kim, Kwang-Sun;Lim, Kyong-Hwa;Jeong, Tae-Gun
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2000.11a
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    • pp.742-747
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    • 2000
  • The optical storage device has recently experienced significant improvements, especially for the aspects of high capacity and fast transfer rate. However, it is the fact that the optical storage device has the lower access time for the randomly scattered data compared to the hard disk drives. It is, therefore, necessary to develop a new type of optical storage system. In this study, we investigate the air bearing characteristics for the optical disk drives which have the swing arm actuator similarly to the hard disk drives. Considering the requirements of the optical disk drives, we parametrize the shape of the air bearing surface and investigate its sensitivity to the flying characteristics for further optimized design outputs.

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Torsional Rigidity of a Two-stage Cycloid Drive (이단 사이클로이드 드라이브의 비틀림 강성)

  • Kim, Kyoung-Hong;Lee, Chun-Se;Ahn, Hyeong-Joon
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.33 no.11
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    • pp.1217-1224
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    • 2009
  • This paper presents a finite element (FE) analysis of the torsional rigidity of a two-stage cycloid drive. The cycloid disk makes contact with a number of pin-rollers simultaneously and eccentric shafts transmit not only torque of the spur gear stage to the cycloid disk, but also that of the cycloid disk to the output disk. Contacts between the disk and pin-rollers are simplified as linear spring elements, and the bearing of eccentric shaft is modeled as a rigid ring that has frictional contact to the disk and an elastic support. FE analysis for an ideal solid cycloid drive was performed and verified by a theoretical calculation. Accurate contact forces were then estimated by iterating between FE analysis for contact forces and Hertz theory calculations for nonlinear contact stiffness. In addition, torsional rigidity of the cycloid drive is analyzed to show that the bearing and nonlinear Hertz contact theory should be considered in analysis and design of a cycloid drive, which was verified with experiments. Finally, the effects of contact stiffness, bearing stiffness and cycloid disk structural stiffness according to the cycloid disk rotation on the torsional rigidity were investigated.

Lubrication Characteristic of a Disk Type Wave Thrust Bearing (Wave가 있는 원판형 추력베어링의 윤활특성)

  • 박태조;제태진;이운섭
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2002.10a
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    • pp.888-891
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    • 2002
  • This paper presents the lubrication characteristics of a disk type wavy thrust bearing. The hydrodynamic pressure distributions in the fluid film are numerically solved the Reynolds equation and then the bearing load capacity and friction forces acting on the disk are calculated. Especially the effects of number and amplitude of the circumferential waves are investigated for tilted operating conditions. The results showed that the load capacity increases with wave amplitude and optimum wave number exists for given design conditions. Therefore the results can be applied to enhance the lubrication performance of thrust bearing adopted in the scroll compressor.

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Finite Element Modal Analysis of a Spinning Flexible Disk-Spindle System Considering the Flexibility of Supporting Structures and an Head-Suspension-Actuator in a HDD (지지구조와 헤드-서스펜션-액츄에이터의 유연성을 고려한 HDD 유연 회전 디스크-스핀들 시스템의 유한 요소 고유 진동 해석)

  • Seo, Chan-Hee;Lee, Ho-Sung;Sang, Gun-Hee
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2006.11a
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    • pp.128-135
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    • 2006
  • This paper presents a finite element method to analyze the free vibration of a flexible HDD composed of the spinning disk-spindle system with fluid dynamic bearings(FDBs), the head-suspension-actuator with pivot bearings, and the base plate with complicated geometry. Experimental modal testing shows that the proposed method well predicts tue vibration characteristics of a HDD. This research also shows that even the vibration motion of the spinning disk corresponding to half-speed whirl and the pure disk mode are transferred to a head-suspension-actuator and base plate through the air bearing and the pivot bearing consecutively. The proposed method can be effectively extended to investigate the forced vibration of a HDD and to design a robust HDD against shock.

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Finite Element Modal Analysis of a Spinning Flexible Disk-spindle System Considering the Flexibility of Supporting Structures and an Head-suspension-actuator in a HDD (지지구조와 헤드-서스펜션-액추에이터의 유연성을 고려한 HDD 유연 회전 디스크-스핀들 시스템의 유한 요소 고유 진동 해석)

  • Seo, Chan-Hee;Lee, Ho-Sung;Jang, Gun-Hee
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.17 no.1 s.118
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    • pp.24-32
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    • 2007
  • This paper presents a finite element method to analyze the free vibration of a flexible HDD composed of the spinning disk-spindle system with fluid dynamic bearings(FDBs), the head-suspension-actuator with pivot bearings, and the base plate with complicated geometry. Experimental modal testing shows that the proposed method well predicts the vibration characteristics of a HDD. This research also shows that even the vibration motion of the spinning disk corresponding to half-speed whirl and the pure disk mode are transferred to a head-suspension-actuator and base plate through the air bearing and the pivot bearing consecutively. The proposed method can be effectively extended to investigate the forced vibration of a HDD and to design a robust HDD against shock.

Development of Performance Evaluation System for Hydrodynamic Bearing in Hard Disk Drive (초소형 HDD용 유체 동압베어링의 동적 성능평가 시스템)

  • Park, S.J.;Lee, H.W.;Song, J.R.;Lee, H.J.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2009.10a
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    • pp.66-68
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    • 2009
  • Most hard disk spindles currently used are supported by oil lubricated hydrodynamic bearings. However, in the trend of increasing spindle speed and reducing size and cost, dynamic behaviors of the bearing such as RRO and NRRO are more important. A novel system evaluating dynamic behavior of hydrodynamic bearings in had disk drive was developed to analyze the effect of groove shapes and parameters.

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Dynamic response of a HDD pivot ball bearing acted by Hertzian contact force (Hertzian contact force에 의한 HDD pivot ball bearing의 동적 반응 분석)

  • Yoon, Joo Young;Park, No-Cheol;Lim, Gunyeop;Park, Young-Pil
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2014.10a
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    • pp.993-993
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    • 2014
  • Increasing the density magnetic recording of a hard disk drive needs to improve position control of a slider. We have troubles analyzing position of a slider by nonlinear property of pivot ball bearing. Many researches analyze a hard disk drive to change pivot ball bearing part from balls to springs. Pivot ball bearing operates by rotation and movement of balls. This study considers Hertzian contact force when balls contact with outer race to analyze nonlinear movement of a ball bearing. Experiment of this study measures movement of a circular center of a pivot ball bearing. We also verify the simulation results and the experiment results.

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A Small Disk-type Hybrid Self-healing Motor (소형 원판형 하이브리드 자기 부상 모터)

  • ;Yohji Okada
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.11 no.8
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    • pp.338-348
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    • 2001
  • A hybrid self-hearing motor, which Is a functional combination of general permanent magnet (PM) motor and hybrid active magnetic bearing(AMB), was proposed a few years ago. In this paper the hybrid self-bearing motor is modified to a disk type, in which one of two magnetic hearings was substituted for a thin yoke to make the system more compact. An outer rotors in this self-hearing motor is actively controlled only in two radial directions while the ocher motions are passively salable owing to the disk-type structure. Main advantages of the proposed self-hearing motor are simple control mechanism, low power consumption and smart structure. Mathematical model for the magnetic force Is built wish consideration of the radial displacement of the rotor. The model helps us not only to design a levitation controller but also to expect the system performance. Some experimental results show good capability and feasibility of the Proposed self-bearing motor.

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The Optimal Design of Air Bearing Sliders of Optical Disk Drives by Using Simulated Annealing Technique (SA 기법을 이용한 광디스크 드라이브 공기베어링 슬라이더의 최적설계)

  • Chang, Hyuk;Kim, Hyun-Ki;Kim, Kwang-Sun;Rim, Kyung-Hwa
    • Proceedings of the KSME Conference
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    • 2001.06c
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    • pp.316-321
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    • 2001
  • The optical storage device has recently experienced significant improvement, especially for the aspects of high capacity and fast transfer rate. However, it is necessary to study a new shape of air bearing surface for the rotary type actuator because the optical storage device has the lower access time than that of HDD (Hard Disk Drives). In this study, we proposed the air bearing shape by using SA (Simulated Annealing) algorithm which is very effective to achieve the global optimum instead of many local optimums. The objective of optimization is to minimize the deviation in flying height from a target value 100nm. In addition, the pitch and roll angle should be maintained within the operation limits.

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