• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.06a
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• pp.495-496
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• 2007

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.06a
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• pp.481-482
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• 2007

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.923-928
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• 2007

The rattle noise originated from the oil-pump system was issued in developing an engine. In this paper, the major concerning factors for rattle noise are analyzed and the NVH developing process is summarized. The main factors are the tip clearance of inner/outer rotor, the clearance between oil pump housing and rotor guide and the rotor mass. Also, the optimization for oil-pump rotor whine noise is performed. The main factors of the rotor whine are the profile of the rotor, the oil pressure and the shape of oil route. This paper will present the design guidelines of the engine oil-pump system.

• International Journal of Fluid Machinery and Systems
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• v.7 no.1
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• pp.16-27
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• 2014

Double-blade vertical axis wind turbines (DB-VAWTs) can improve the self-starting performance of lift-driven VAWTs. We here propose the quadruple-multiple streamtube model (QMS), based on the blade element momentum (BEM) theory, for simulating DB-VAWT performance. Model validity is investigated by comparison to computational fluid dynamics (CFD) prediction for two kinds of two-dimensional DB-VAWT rotors for two rotor scales with three inner-outer radius ratios: 0.25, 0.5, and 0.75. The BEM-QMS model does not consider the effects of an inner rotor on the flow speed in the upwind half of the rotor, so we introduce a correction factor for this flow speed. The maximum power coefficient predicted by the modified BEM-QMS model for a DB-VAWT is thus closer to the CFD prediction.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.901-902
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• 2010

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.139-140
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• 2011

• Proceedings of the KIEE Conference
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• 2007.11c
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• pp.149-154
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• 2007

The classical literature on SR motor design tends to focus on inner-rotor type motor rather than outer-rotor type motor, and dose not provide a complete procedure for configuration of outer-rotor type SR motor calculations that are also needed in every SR motors design. It is interested in the design of SR motors to shortening the magnet flux path in the iron core for reducing the iron loss. The 5 phases outer-rotor type SR Motor with short magnet flux path is introduced in this paper. For this the rotor of prototype is designed in U-form with 8 rotor poles that are in 4 U-forms from one another separate constructed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.559-564
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• 2001

In order to apply into a compact and reliable centrifugal blood pump, this paper introduces a self-bearing motor in which a rotor is rotated without contact. The rotor is actively controlled in only radial directions, while the axial and tilting motions are passively stable owing to the disk-shape structure of the rotor. A prototype was made in outer-rotor type that is far better in the compactness than inner-rotor type. The prototype could be driven up to 8000 rpm with the rotor vibration under 0.12mm. The maximum cardiac output and pressure head were 9 L/min and over 200 mmHg, respectively. These experimental results show that the proposed self-bearing motor has sufficient performance for application to a real blood pump.

• Proceedings of the KIEE Conference
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• 1995.07a
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• pp.86-88
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• 1995

Outer-rotor type brushless motor is designed to run at more constant speed because of large inertia comparing with inner-rotor type. The constant speed is acquired by increasing inertia. Also, the generating torque is proportional to the rotor volume, i. e. rotor diameter. The main idea in this study is to design and analyze the outer-rotor type brushless motor by permeance method with given outer dimension.

• International Journal of Precision Engineering and Manufacturing
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• v.3 no.2
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• pp.61-71
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• 2002

This paper presents the dynamic analysis of indeterminate rotor systems with angular contact ball bearings subject to axial and radial loads. The reaction forces against applied radial loads significantly influence the dynamic characteristics of angular contact ball bearings. However, the reaction forces are hard to determine in the case of indeterminate rotor-bearing systems. To this end, this paper proposes a finite element model for indeterminate rotor systems with angular contact ball bearings. An improved bearing model is adopted which is originated from the Harris's bearing dynamic model. The bearing model is also extended to include centrifugal forces due to the ball and inner ring. This paper utilizes a new iterative algorithm for general, indeterminate rotor systems with angular contact ball bearings. This examples are provided to illustrate the dynamic characteristics of rotor systems with angular contact ball bearings subject to axial and radial loads. The experimental and numerical results prove that the proposed method is useful for the dynamic analysis of indeterminate rotor systems with angular contact ball bearings.