통합 검색 | Korea Science

김동현;이춘만
- 한국정밀공학회지
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- 제27권12호
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- pp.119-124
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- 2010
In this paper, thermal stabilization design of a new concept compact machining center has been investigated. A new concept machining center adopted a new X-axis as a NC rotary table. A New concept compact machining center is designed that spindle speed, feed rate and NC Rotary table speed are 12,000rpm, 60m/min and 110rpm each. The analysis is carried out by using FEM simulation Solidworks, CATIA and ANSYS. This paper is focused on the thermal deformation according to temperature distribution of a spindle system and feed drive system. Heat transfer analysis is performed according to heat source and atmosphere contact parts. As a result, this compact machining center is designed as a thermally stable structure.
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김종립;윤기찬;박종권
- 한국정밀공학회지
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- 제15권6호
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- pp.145-152
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- 1998
This paper presents an optimum design of a rotor-bearing spindle system for a ultra centrifuge (80,000 RPM) supported by ball bearings with nonlinear stiffness characteristics. To obtain the nonlinear bearing stiffnesses, a ball bearing is modeled in five degrees of freedom and is analyzed quasi-statically. The dynamic behaviors of the nonlinear rotor-bearing system are analyzed by using a transfer-matrix method iteratively. For optimization. we use the cost function that simultaneously minimizes the weight of a rotor and maximizes the separation margins to yield the critical speeds as far from the operating speed as possible. Augmented Lagrange Multiplier (ALM) method is employed for the nonlinear optimization problem. The result shows that the rotor-bearing spindle system is optimized to obtain 9.5％ weight reduction and 21％ separation margin.
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Na, Hee-Hyeong;Rhim, Yoon-Chul
- KSTLE International Journal
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- 제1권1호
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- pp.63-68
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- 2000
Angular contact ball bearings are mainly used in the spindle, which requires high speed and stiffness. The heat generation is studied by experiments and simulations using a pair of angular contact ball bearings. The temperature variation of inner and outer races and the temperature increment distribution are measured by using thermocouples for the rotational speed, preload, viscosity of lubricant. The measured values from experiments are used to estimate the heat conduction rate. The method of oil-air lubrication is used for the experiment. The amount of conduction heat transfer to the test spindle and the convection heat transfer coefficients long the spindle are computed by using inverse method with temperature increment distribution. Total heat generation rate is estimated with the heat partition rate which is calculated from temperatures of inner and outer races. In addition, the empirical factor of oil-air lubrication method for Palmgren's heat generation model is suggested. The empirical friction coefficients, which are obtained from the experiments, depend on the preload condition, and can give us more accurate estimation of the heat generation in ball bearings.
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박한수;정택구;홍준희;이동주
- 한국공작기계학회:학술대회논문집
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- 한국공작기계학회 2002년도 추계학술대회 논문집
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- pp.411-416
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- 2002
In a high speed spindle system, it is very important to monitor the state of rotating rotor. Particularly in active control spindle system, the position sensor must provide feedback to the control system on the exact position of the rotor. In order to monitor the state of a high speed spindle exactly, high accuracy and wide frequency bandwidth of sensors are important. The focus in this paper is to make a fiber optic sensor for monitoring rotor of magnetic bearing, to design the circuit for detecting optical signal, and to evaluation static and dynamic characteristics of fiber optic sensor.
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