• Title/Summary/Keyword: Conical bearing

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A Study on the Characteristics of an Externally Pressurized Conical Gas Bearing (외부가압 원추형 공기베어링의 특성에 관한 연구)

  • 박상신;한동철
    • Tribology and Lubricants
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    • v.7 no.1
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    • pp.35-39
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    • 1991
  • The performance of the ultra-precision machine tools depends on the steady state characteristics of the main spindle bearings. For excluding the effect of machining error with perpendicularity, conical or spherical bearing has been used. In this paper, steady analysis of the externally pressurized conical gas bearing for ultraprecision is carried out based on the direct numerical method with assumption of point source. As a result of theoretical analysis, design parameters for optimal condition of conical gas bearing are' presented in dimensionless form.

Dynamic Characteristics of an Externally Pressurized Conical Gas Bearing (외부가압 원추형 공기 베어링의 동특성에 관한 연구)

  • 박상신;김우정;김종원;한동철
    • Tribology and Lubricants
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    • v.8 no.1
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    • pp.78-83
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    • 1992
  • For excluding the effect of machining error such as perpendicularity, conical and spherical bearing has been used. In this paper, dynamic characteristics of the externally pressurized conical gas bearing for untraprecision main spindle is carried out based on the direct numerical method with assumption of point source. As a result of theoretical analysis, it is verified that coupled stiffness and damping exist and new design parameters for optimal condition of conical gas bearing are presented in dimensionless form.

Analysis of a Journal and Thrust FDB and a Conical FDB in the Spindle Motor of a Computer Hard Disk Drive (HDD 스핀들 모터용 저널-스러스트 유체동압 베어링과 코니컬 유체동압 베어링의 특성해석비교)

  • Kim, Bum-Cho;Jang, Gun-Hee
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2005.05a
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    • pp.478-483
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    • 2005
  • This paper presents the comparison analysis of a Journal and thrust FDB (fluid dynamic bearing) and a conical FDB in a HDD spindle motor. The Reynolds equation is appropriately transformed to describe journal, thrust and conical bearing. Finite element method is applied to analyze the FDB by satisfying the continuity of mass and pressure at the interface between the hearings. The pressure field of the bearings is numerically approximated by applying the Reynolds boundary condition. The load and friction torque are obtained by integrating the pressure and the velocity gradient along the fluid film. The flying height of the spindle motor is measured to verify the proposed analytical result. This research shows that the conical bearing generates bigger load capacity and less friction torque than the journal and thrust bearing in a HDD spindle motor.

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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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Multipath Track Association Technique using Characteristics of Conical Bearing in Horizontal Line Array Sonar (수평 선배열 소나의 원추각 특성 기반 다중경로 트랙 연관 기법)

  • Raegeun Oh
    • Journal of the Korea Institute of Military Science and Technology
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    • v.27 no.2
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    • pp.156-166
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    • 2024
  • This paper conducts a study on methods for associating multipath tracks received by a horizontal line array sonar. The horizontal line array sonar introduces conical bearing ambiguities due to its array-shaped characteristics. Target signals are often subject to multipath propagation in the ocean, resulting in errors in target bearing estimation due to these bearing ambiguities. Recent research efforts have been directed toward using multipath tracks to estimate the positions of targets. However, there has been a lack of research dedicated to identifying multipath tracks from the measurements of a horizontal line array sonar. Therefore, this study identifies the conical bearing characteristics of multipath signals based on the result of experiment and establishes criteria for associating multipath tracks. Additionally, Simulations are performed to determine the ability to associate multipath tracks.

Ultimate bearing capacity of conical shell foundations

  • Colmenares, J.E.;Kang, So-Ra;Shin, Young-Jin;Shin, Jong-Ho
    • Structural Engineering and Mechanics
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    • v.52 no.3
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    • pp.507-523
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    • 2014
  • Shell foundations have been employed as an alternative for the conventional flat shallow foundations and have proven to provide economical advantage. They have shown considerably improved performance in terms of ultimate capacity and settlement characteristics. However, despite conical shell foundations are frequently used in industry, the theoretical solutions for bearing capacity of these footings are available for only triangular shell strip foundations. The benefits in design aspects can be achieved through theoretical solutions considering shell geometry. The engineering behavior of a conical shell foundation on mixed soils was investigated experimentally and theoretically in this study. The failure mechanism was obtained by conducting laboratory model tests. Based on that, the theoretical solution of bearing capacity was developed and validated with experimental results, in terms of the internal angle of the cone. In comparison to the circular flat foundation, the results show 15% increase of ultimate load and 51% decrease of settlement at an angle of intersection of $120^{\circ}$. Based on the results, the design chart of modified bearing capacity coefficients for conical shell foundation is proposed.

Analysis of the Fluid Dynamic Bearings with Curve Surfaces in the Spindle Motor of a Computer Hard Disk Drive (컴퓨터 하드 디스크 드라이브 스핀들 모터에 사용되는 곡면 유체 동압 베어링 해석)

  • Kim, Hak-Woon;Jang, Gun-Hee
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2008.11a
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    • pp.401-406
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    • 2008
  • This paper proposes a method to calculate the static characteristics of the FDBs with the curved surface. The general Reynolds equations are derived for the curved surfaces in the ${\theta}s$ plane. And the Reynolds equation is transformed to the finite element equations by considering the continuity of pressure and flow at the interface between the curved, journal and the thrust bearings. It also includes the Reynolds boundary condition in the numerical analysis to simulate the cavitation phenomenon. The static characteristics of the coupled journal and conical bearings were investigated due to the variation of conical angle. It shows that the conical angle is one of the important design parameters affecting the static and dynamic characteristics of FBBs.

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An Analysis and Test for Leakage Flow of Sealless Cylinder (고성능 씰리스 실린더의 해석 및 누설유량 시험)

  • Kim, Sung-Jong;Kim, Dong-Soo;Lee, Seung-Hyun
    • Proceedings of the KSME Conference
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    • 2004.04a
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    • pp.961-966
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    • 2004
  • The cylinder without seal has a piston with air bearing which is partly cylindrical and conical shape. The description of system geometry is deviation by the flow rate equation. Then pressure distribution and bearing force equations are derived. Several non-dimensional parameters are suggested. The relationship among bearing force, leakage flow and geometry of the bearing is investigated by simulation. And determination method for optimal design of sealless cylinder is given. A prototype of sealless cylinder which had rod bearing with four pockets, five pockets, and six pockets was built respectively. As a result of leakage flow test, it is evaluation to air bearing in sealless cylinder.

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

  • 김성균;박상신;김우정;한동철
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 1993.12a
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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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Analysis of the Conical Air Bearings with two Circumferential Grooves (2열 원주 그루브 급기 원추형 공기베어링의 해석)

  • 김성균;박상신;한동철
    • Tribology and Lubricants
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    • v.10 no.1
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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.