• 대한기계학회논문집A
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• 제40권1호
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• pp.41-51
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• 2016

볼나사 시스템은 볼과 그루브 사이에서 발생하는 마찰에 의해 온도가 상승하며, 이에 따른 열변형이 이송계의 위치결정 정도를 저하시킨다. 이를 보상하기 위해서는 볼나사 온도분포의 우선적 예측이 필요하다. 본 논문에서는 나사축 회전속도에 따른 온도분포를 해석하기 위해 볼나사 축과 너트를 각각 실린더와 중공 실린더로 가정한다. 경계조건인 대류 열전달계수, 볼과 그루브에서 발생하는 마찰토크와 접촉열전도를 볼나사 운전 및 조립 조건에 대하여 정식화 한다. 그리고, 현시적 유한차분법을 적용한 온도 분포 예측 시뮬레이터를 개발하고 그 유용성을 검증한다.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1997년도 춘계학술대회 논문집
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• pp.76-81
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• 1997

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1994년도 추계학술대회 논문집
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• pp.254-259
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• 1994

Recently, the precision ball screw becomes the essence of the high-precision industries and is playing a key role in the positioning devices. The standard and definition of pitch error in a precision ball screw is specified by KS, JIS or ISO. However, the method of measuring the pitch error is not concrete. In this study. laser measurement system(LMS) with a laser position transducer and a machine-tools is developed. In order to verify the stability of the LMS, several experiments with the standard ball screw is performed.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1997년도 추계학술대회 논문집
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• pp.31-36
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• 1997

Thermal expansion of the ball screw in semi-closed loop type CNC Lathe directly affects the position precision along the travel axis. In this paper, the thermal displacement of the ball screw is estimated by using macro variables. The estimated displacements of the ball screw are managed by calculating the interval of pitch error rate in the NC. The thermal behaviour of the ball screw of the CNC Lathe, under the constant operating conditions, was measured to examine the effectiveness of this compensation method. The results showed that thermal displacement of the ball screw could be maintained its accuracy better than 6${\mu}{\textrm}{m}$ while applying this method.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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• pp.43-47
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• 1995

The ball screw is one of the important mechanical parts for the linear motion feeding systems. The usage of the ball screw has been growing in various industrial fields such as CNC machine tool, industrial robot and automated systems. Because of ever increasing demand for ball screws, increased accuracy and quality of the ball screw is needed,especially the surface roughness of the ball contact area in order to diminish noise and vibration. Therefore to improve the surface roughness of the area,we introduced magnetic assisted polishing which is one of the new potential polishing methods. In this study, diamond slurry and iron powder was used for magnetic assisted polishing of the ball bearing surface. This polishing process was experimentally confirmed to improve the surface roughness of the ball bearing.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.292-295
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• 2001

Conventional robots actuated by motors with the speed reducer such as harmonic drive had weakness in delivering loads, pressing, grinding, and cutting jobs. To overcome this, a new type of robot actuated by the ball screw was proposed. The ball screw is actuated by using four bar mechanism. The dynamics model of the robot was set up. The robot has parameter uncertainties and nonlinearlity due to the ball screw actuator. To coordinate the robot, the sliding-mode control was applied.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 춘계학술대회 논문집
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• pp.894-899
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• 1997

Genernally, the life of ball screws is presented in catalogue of domestic manufacturer by the name of dynamic load capacity. But, systematic experiment method and reliable data are not secured, even now. Data presented in catalogue is obtained at already established life expression of ball-bearing. Therefore studying on the life of ball screws, characteristic qualities of ball screw must be considered. We studied systematic experiment method and by this do experiments, obtained data. This paper present above items, and expression of life prediction by experiment results.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.323-326
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• 1997

Conventional robots actuated by motors with the speed reducer such as harmonic drive had weakness in delivering loads, pressing, grinding, and cutting jobs. To overcome this, the developer a new type of robot actuated by the ball screw. The robot is an articulated shape, which is composed of four axes. The base axis is actuated similarly with conventional robot, but the others are actuated by four bars mechanism composed of the ball screw. We setup the dynamics model of the robot. The robot has parameter uncertainties and nonlinearlity due to the ball screw actuator. To coordinate the robot, we applied sliding-mode control.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 춘계학술대회 논문집
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• pp.583-586
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• 2000

The conventional actuators with the speed reducer had weakness in supporting the weight of the body and leg itself. To overcome this, a new four bar link mechanism actuated by the ball screw was proposed. The four bar mechanism has higher strength and gear ratio than the conventional actuator to actutate the leg of the biped robot. One leg was designed to have ankle, thigh, and hip joints. The kinematics and dynamics of one leg with four bar link mechanism was analyzed using Euler-Lagrange approach. The dynamics of one leg was expressed in the ball strew frame.

• 한국공작기계학회논문집
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• 제11권3호
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• pp.51-56
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• 2002

In order to achieve high precision machine tools, Performance enhancement of feed drive systems is required. One of the important technical issues is how to decrease thermal expansion of ball screw in proportion to the increase of machining speed. When measuring force of stretch of ball screw, since not only actual expansion and the value of bending have to be considered, it is impossible to define the exact value of expansion. In addition, support bearings of ball screw gain considerable force in axial direction. It also generates thermal expansion on the ball screw, and deteriorates the performances of the hearings. In conclusion, it is impossible to give the pretension enough to absorb all the elongation due to thermal expansion generated during machine is running. If given bed column and saddle are all bent to chance machine accuracy, and the support bearings of ball screw is damaged.