• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1996.04a
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• pp.53-59
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• 1996

오늘날 산업현장에서 사용되는 대부분의 기계와 가전 제품에는 회전기계가 중요한 역할을 담당하고 있고, 이러한 회전 요소에서 종종 진동이 발생하여 문제가 되고 있다. 이러한 진동이 발생시키는 원인 중에서도 회전체의 불평형(unbalance)이 대부분이다. 이러한 불평형 중에도 매 운전 사이클마다 불평형의 크기나 위치가 바뀌는 경우에는 평형잡이 기계로는 불평형을 수정할 수 없다. 이를 자동적으로 수정하는 장치로써 Thearle가 볼(steel ball)을 이용한 자동평형장치를 제안하였고, 정상는 2개의 볼을 내장한 1개 또는 2개의 원판을 설치하여 계의 기본적인 진동특성을 조사하였다. 그리고 볼과 저점성유체를 내장한 단일원판의 자려진동에 대한 안정성을 조사한 연구결과도 있다. 본 연구에서는 위의 이론들을 기초로 하여 1) 2개의 원판을 모델한 기본적인 진동거동, 2) 자동 평형장치로서 이용가능한 운전영역과 자려진동의 발생 영역 및 조건, 3) 계의 파라메터, 즉 각가속도, 원판내의 유체의 점성계수 및 볼의 갯수의 변화에 대한 자동평형장치의 성능 등을 실험적으로 조사하였다.

• Journal of KSNVE
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• v.9 no.2
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• pp.355-362
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• 1999

Vibration reduction of an optical disk drive is achieved by an automatic ball balancer and dynamic behaviors of the drive are studied by theoretical approaches. Using Lagrange's equation, we derive nonlinear equations of motion for a non-autonomous system with respect to the rectangular coordinate. To investigate the dynamic stability of the system in the neighborhood of equilibrium positions, the Floquet theory is applied to the perturbed equations. On the other hand, time responses are computed by an explicit time integration method. We also investigate the effects of mass center and the position of the ABB on the dynamic behaviors of the system.

• Journal of KSNVE
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• v.9 no.2
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• pp.387-392
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• 1999

This paper presents design guidelines for the automatic ball balancer in CD/DVD systems with varying eccentricity. In these systems, the size of balancing balls should be limited by the restricted race space so that determination of the number and mass of balls should consider the radii of the race and the balls. In addition, the effects of viscosity and friction also should be taken into account for sufficient balancing. Based on the static equilibrium conditions, the number and mass of balls corresponding to the range of varying eccentricity have been determined. Dynamic simulation with viscosity and friction shows sufficient viscosity must exist to ensure stability and friction between balls and race must be minimized to guarantee accurate balancing.

• Journal of KSNVE
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• v.9 no.2
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• pp.363-370
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• 1999

In this study, we establish a theory for dynamic behaviors of an automatic ball balancer, analyze its dynamic characteristics, and provide its design guide line. Equations of motion are derived by using the polar coordinate system instead of the rectangular coordinate system which was previously used in other researches. After nondimensionalization of the equations, the perturbation method is applied to locate the equilibrium positions and to obtain the linearized equations of motion around the equilibrium positions. The Eigenvalue problem is used to verify the dynamic stability around the equilibrium positions. On the other hand, the time responses are computed from the nonlinear equations of motion by using a time integration method.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.59-68
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• 2005

In this study, we establish a theory for dynamic behaviors of an automatic ball balancer, analyze its dynamic characteristics, and provide its design guide line. Equations of motion are derived by using the polar coordinate system instead of the rectangular coordinate system which was previously used in other researches. After non-dimensionalization of the equations, the perturbation method is applied to locate the equilibrium positions and to obtain the linearized equations of motion around the equilibrium positions. The Eigenvalue problem is used to verify the dynamic stability around the equilibrium positions. On the other hand, the time responses are computed from the nonlinear equations of motion by using a time integration method.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.12
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• pp.2511-2518
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• 2002

Dynamic behaviors and stability of an optical disk drive coupled with an automatic ball balancer (ABB) are analyzed by a theoretical approach. The feeding system is modeled a rigid body with six degree-of-freedom. Using Lagrange's equation, we derive the nonlinear equations of motion for a non -autonomous system with respect to the rectangular coordinate. To investigate the dynamic stability of the system in the neighborhood of the equilibrium positions, the monodromy matrix technique is applied to the perturbed equations. On the other hand, time responses are computed by the Runge -Kutta method. We also investigate the effects of the damping coefficient and the position of ABB on the dynamic behaviors of the system.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11b
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• pp.983-988
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• 2001

Dynamic behaviors and stability of an optical disk drive coupled with an automatic ball balancer(ABB) are analyzed by a theoretical approach. The feeding system is modeled a rigid body with six degree-of-freedom. Using Lagrange's equation, we derive the nonlinear equations of motion for a non-autonomous system with respect to the rectangular coordinate. To investigate the dynamic stability of the system in the neighborhood of the equilibrium positions, the monodromy matrix technique is applied to the perturbed equations. On the other hand, time responses are computed by the Runge-Kutta method. We also investigate the effects of the damping coefficient and the position of ABB on the dynamic behaviors of the system.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.418-423
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• 2003

The balancing performance of an automatic ball balancer (ABB) in the vertical or horizontal position is studied in this paper. Considering the effects of gravity and angular velocity profiles, a physical model for an ABB installed on the Jeffcott rotor is adopted. The non-linear equations of motion for the rotor with ABB are derived by using Lagrange's equation. Based on derived equations, dynamic responses for the rotor are computed by using the generalized-u method. From the computed responses, the effects of gravity and angular velocity profiles on the balancing performance are investigated. It is found that the rotor with ABB can be balanced regardless of the gravity effect. It is also shown that a smooth velocity profile yields relatively smaller vibration amplitude than a non-smooth velocity profile.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.5
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• pp.511-516
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• 2004

The dynamic behavior of an automatic ball balancer (ABB) is studied considering the effects of gravity and angular velocity profiles. In this study, a physical model for an ABB installed on the Jeffcott rotor is adopted in order to investigate the effects of gravity and angular acceleration. The equations of motion for the rotor with ABB are derived by using Lagrange's equation. Based on derived equations, dynamic responses for the rotor are computed by using the generalized-o method. From the computed responses, the effects of gravity and angular velocity profiles on the dynamic behavior are investigated. It is found that the balancing of the rotor with ABB can be achieved regardless of gravity. It Is also shown that a smooth velocity profile yields relatively smaller vibration amplitude than a non-smooth velocity profile.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.5 s.176
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• pp.1093-1102
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• 2000

Dynamic behaviors are analyzed for an automatic ball balancer with double races which is a device to reduce eccentricity of rotors. Equations of motion are derived by using the polar coordinate sys tem instead of the rectangular coordinate system which is used in other previous researches. To analyze the stability around equilibrium positions, the perturbation method is used. On the other hand, the time responses are computed from the nonlinear equations of motion by using a time integration method.