• The Transactions of the Korean Institute of Electrical Engineers B
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• v.52 no.10
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• pp.507-513
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• 2003

Nowadays, the necessity of linear position control motors have been increased in the various fields of the automatic control system. In the recently, the position control motor have disadvantaged in the efficiency and economical view since it require a conversion equipments such as belt and gear in order to convert rotary to linear motion. On the contrary, the hybrid linear stepping motor(HLSM) of linear motion digital actuator has a direct drive method that do not need mechanical conversion equipments. Therefore, the HLSM is better advantaged in the efficiency and economical view than a rotary stepping motor. In this paper, we have designed an optimum tooth shape and a permanent magnet value between the mover teeth by the 2D finite element method(FEM) to develop the HLSM with longitudinal flux machine(LFM) type, and calculated the thrust force and normal force. And we have manufactured the prototype of it. and have experimented the thrust force and the dynamic thrust characteristics of it.

• Proceedings of the KIEE Conference
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• 1994.07a
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• pp.43-45
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• 1994

This paper proposes the new method to calculate the static thrust and normal force of a hybrid type double-sided linear pulse motor by the coenergy which considered the magnetic nonlinealities. In the process of the computation, the nonlinear characteristics of the magnetic material were interpolated by the cubic spline method. And, to investigate the characteristics of the hybrid type DLPM, the static thrust and the normal force is shown as a function of displacement, input current and air airgap length. Also the simulation values are compared with the experimental ones obtained from a hybrid type DLPM.

• Proceedings of the KIEE Conference
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• 1999.07a
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• pp.160-163
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• 1999

The thrust force of moving magnet-type linear direct current motors(MM-LDM) is analyzed in this study. A moving magnet-type LDM consists of a stator and a carriage. The stator is composed of two stick shaped electro magnetics and the carriage consists of a movable permanent magnet that is located between the two electromagnets. The method for calculating the thrust force of an MM-LDM is to analyze the energy gradient which is determined by the distribution of magnetic flux. And this paper describes the development of the generalized machine theory for d.c. linear motors and its application to determine the motor parameters.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.55 no.10
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• pp.498-504
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• 2006

Thrust force of linear motor is one of the important factor to specify motor performance. In this study, we optimized maximizing the thrust force of TFLM(Transverse Flux Linear Motor) using Response Surface Methodology by the table of orthogonal way. The Response Surface Methodology was well adapted to make the analytical model of the maximum thrust force and enable the objective function to be easily created and a great deal of the time In computation to be saved. Therefore, it is expected that the proposed optimization procedure using the Response Surface Methodology can be easily utilized to solve the optimization problem of electric machine.

• Tribology and Lubricants
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• v.25 no.5
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• pp.292-297
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• 2009

Air foil thrust bearings are the critical components available on high-efficiency turbomachinery which need an ability to endure the large axial force. Air foil bearings are self-acting hydrodynamic bearings that use ambient air as their lubricant. Since the air is squeezed by the edge of compliance-surface of bearing, hydrodynamic force is generated. In this study, we measured the air film thickness and obtained the minimum film thickness experimentally. To increase the maximum load capacity, compliance of sub-structure was controlled. From numerical analyses, it is seen that, if the air film thickness is distributed more uniformly by variable compliance, the thrust bearings can take more axial load.

• Tribology and Lubricants
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• v.26 no.1
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• pp.1-6
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• 2010

In the last decade, laser surface texturing (LST) has emerged as a viable option of surface engineering. Many problems related with mechanical components such as thrust bearings, mechanical face seals and piston rings, etc, LST result in significant improvement in load capacity, wear resistance and reduction in friction force. It is mainly experimentally reported the micro-dimpled bearing surfaces can reduce friction force, however, precise theoretical results are not presented until now. In this paper, a commercial computational fluid dynamics(CFD) code, FLUENT is used to investigate the lubrication characteristics of a parallel thrust bearing having 3-dimensional micro-dimple. The results show that the pressure, velocity and density distributions are highly affected by the location and number of dimple. The numerical method and results can be use in design of optimum dimple characteristics, and further researches are required.

• 한국전산유체공학회:학술대회논문집
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• 2010.05a
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• pp.258-262
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• 2010

Since MEMS based micro actuators or generating devices showed high efficiency per volume, plenty of research are ongoing. Among them, MEMS based millimeter-scale micro gas turbine is one of the most powerful item for replacing chemical batteries. However, due to MEMS manufacturing technique, it is very difficult that makes wide turbine bearing area. It causes low DN number, so sufficient bearing force is hard to achieve. Thus, the most important issue on micro gas turbine is to design the proper bearing which can keep rotor stable during operation. In order to that, micro-scale gas-lubricated bearing is generally used. In this paper, basic feasibility study of thrust bearing of 10mm diameter turbine is described. Thrust bearing is hydrostatic gas-lubricated type. Numerical simulation is performed with ANSYS CFX 11.0 which is commercial numerical tool. Relationship between bearing inlet pressure and mass flow rate and bearing force is figured while changing bearing gap and number of capillaries. The simulation results will be used for further design of micro gas turbine.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.14 no.4
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• pp.55-61
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• 2015

In this paper, the grinding characteristics of internal thrust grinding were studied with vitreous CBN wheels using a machining center. Grinding experiments were performed according to grinding conditions, such as wheel feed speed and depth of cut, workpiece speed, and rate of grinding width. Additionally, the grinding force and grinding ratio were investigated though these experiments. Based on the experimental results, the grinding characteristics of internal thrust grinding were discussed.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.15 no.5
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• pp.73-79
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• 2016

In this paper, the grinding characteristics in thrust internal grinding have been studied using vitreous CBN wheels with a machining center. Grinding experiments have been performed according to grinding conditions such as wheel feed speed, cut depth, workpiece speed, rate of grinding width and number of grinding passes. The machining error, shape of machined surfaces, grinding force, and surface roughness have been investigated though these experiments. Based on the experimental results, the grinding characteristics on the machined surface in the internal thrust grinding are discussed.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.54 no.2
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• pp.53-59
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• 2005

In this paper, optimum shape design of permanent magnet in slotted type Permanent Magnet Linear Synchronous Motor(PMLSM) is progressed for minimization of detent force owing to structure of slot-teeth and thrust ripple by harmonic magnetic flux of permanent magnet. In order to reduce remodeling time as changing design parameter for Permanent Magnet shape optimization, the moving model node technique was applied. The characteristics of thrust and detent force computed by finite element analysis are acquired equal effect both skewed basic model and optimum model which is optimization of permanent magnet shape. In addition to, thrust per unit volume is improved 4.l2[%] in optimum model.