• 제목/요약/키워드: Ball-Screw

검색결과 232건 처리시간 0.035초

실시간 볼 스크류 열변형 추정에 관한 연구 (A Study on the Real-Time Estimation of Thermal Displacement for a Ball Screw)

  • 김수광;류승호;조동우
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 1995년도 춘계학술대회 논문집
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    • pp.88-93
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    • 1995
  • The ball screw preloaded for high nigidity and accuracy increases frictional resistance, therefore, its temperature and positioning error rise. In this paper, 2 diamensional temperature distributions of a ball screw with preload are analyzed according to the rotational speeds and stop times by a finite element method. The theremal behaviors of a ball screw are measured to examine the analyzed datum. The examined results show that the trends of temperature rising and axial distributions in steady state are nearly extimate but the temperature low. The differences of temperature ate seems to be caused by not exact heat transfer coefficients. More than an hour is consumed for calculation by FEM. So the modified lumped method for the real-time estimation of the thermal distribution is proposed. The estimated temperature of a ball serw by the modified lumped method is more exactly estimated than by FEM, nd that method takes less than several millisec. Moreover it can be used to estimate heat transfer coefficients.

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유한차분법을 이용한 볼스크류 시스템의 열팽창 해석

  • 박정균;정성종
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 1991년도 추계학술대회 논문집
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    • pp.101-104
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    • 1991
  • Bal1 screw systems has been used for positioning elements of machine tools. In order to maintain high rigidity and accuracy, preload is applied between nut and screw. However, large amount of preload increases frictional heat. Temperature rises remarkably at high speed notion, Thermal expansion degrades positioning accuracy, In this paper, finite differance method is applied to compute temperature distributions and thermal expansions of ball screw systems according to preload condition and rotational steed. Some simulation results show that the developed methodology is good to study thermal expansion of ball screw systems.

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볼스크류 이송계의 진동 최소화를 위한 이송속도 최적화 (A Study on the Feed Rate Optimization of a Ball Screw Feed Drive System for Minimum Vibrations)

  • 최영휴;홍진현
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2004년도 추계학술대회논문집
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    • pp.962-966
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    • 2004
  • Ball screw feed drive systems have been broadly used in machine tools or precision automatic feed systems. Recently, modern machine tools require high speed and high precision and drive system to achieve high productivity. Unfortunately, a feed drive system, even though it was optimum designed, may experience severe transient vibrations during high-speed operation if its feed rate control is unsuitable. A rough feed rate curve having discontinuity in its acceleration profile causes a serious vibration problem in the feed slide system. This paper presents a feed rate optimization of a machine tool feed slide system, which is driven by a ball screw, for its minimum vibrations. Firstly, a 6-degree-of-freedom lumped parameter model was proposed for the vibration analysis of a ball screw driven machine tool feed drive system. Next, a feed rate optimization of the feed slide was carried out for minimum vibrations. The feed rate curve optimization strategy is to find out the most appropriate acceleration profile having finite jerk. Of course, the optimized feed rate should approximate to the desired one as possible. A genetic algorithm with variable penalty function was used in this feed rate optimization.

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볼스크류 가공용 선회형 스핀들의 발열 특성에 관한 연구 (Heat Generation Characteristics of Whirling Spindle for Ball Screw Machining)

  • 문홍만;김상원;정호인;이춘만
    • 한국기계가공학회지
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    • 제19권10호
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    • pp.44-51
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    • 2020
  • We studied the heating characteristics of a whirling spindle. This spindle is an important component of a whirling machine for turning a ball screw shaft. In the manufacturing process for a conventional ball screw shaft, a single tool is used to form a spiral in a lathe machine tool. Thereafter, a high-frequency heat treatment process is performed. Recently, a whirling-type cutting method has emerged. This method can perform hard turning in the rotating direction of the spiral portion of the ball screw shaft by rotating and mounting multiple tools. The whirling method can be applied to the heat-treated material. In this study, an experimental apparatus was constructed to analyze the whirling spindle. The experiment proceeded in four steps. The rotating speed of the whirling spindle was set to ISO random and sequential rising conditions. Cooling and non-cooling modes in the cooling jacket were tested. As a result of the above experiment, the heating characteristics of the whirling spindle were derived.

Surface Mounting Device의 동역학적 모델링 및 상태 민감도 해석

  • 장진희;한창수;김정덕
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 1995년도 추계학술대회 논문집
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    • pp.628-634
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    • 1995
  • In the area of assembly process of micro-chips and electronic parts on the printed circuit board, surface mounting device(SMD) is used as a fundamental tool. Generally speaking, the motion of the SMD is based on the ball screw system operated by any type of actuators. The ball screw system is a mechanical transformer which converts the mechanical rotational motion to the translational one. Also, this system could be considered as an efficient motion device against mechanical backash and friction. Therefore a dynamic modeling and stste sensitivity analysis of the ball screw system in SMD have to be done in the initial design stage. In this paper, a simple mathematical dynamic model for this system and the sensitivity snalysis are mentioned. Especially, the bond graph approach is used for graphical modeling of the dynamic system before analysis stage. And the direct differentiation method is used for the state sensitivity analysis of the system. Finally, some trends for the state variables with respect to the design variables could be suggested for the better design based on the results on the results of dynamic and state sensitivity.

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폐체인 구조의 새로운 다관절 로봇 매니퓰레이터 개발 (Development of a New Robot Manipulator Driven by the Closed-chain Actuator)

  • 최형식;백창열
    • Journal of Advanced Marine Engineering and Technology
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    • 제27권2호
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    • pp.238-245
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    • 2003
  • To overcome the weakness in the load capacity of conventional robot manipulators actuated by motors with the speed reducer such as the harmonic driver, we proposed a new closed-chain type of the robot actuator which is composed of the four-bar-link mechanism driven by the ball screw. The robot manipulator is revolute-jointed and composed of four axes. The base axis is actuated by the lineal actuator such as the ball screw, and the others are actuated by the proposed actuator. We analyzed the mechanism of the actuators of the robot joints, and developed the dynamics model. The dynamics are expressed in the joint coordinates and then they are mapped into the sliding coordinates of the ball screw. We performed fundamental tests on the structure of the robot.

연속 슬라이딩 모드를 이용한 공압모터 구동 볼스크류 위치제어 시스템 (The Ball Screw Position Control System Driven by a Pneumatic Motor Using Continous Sliding Mode)

  • 김근묵
    • 한국산업융합학회 논문집
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    • 제11권4호
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    • pp.209-216
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    • 2008
  • The ball screw position control system driven by a pneumatic motor using continuous sliding mode is proposed. The design and performance of proposed servo system are presented by means of examples tested under practical service conditions. Results of experimental implementation on the proposed system illustrate the effectiveness of the ball screw position control system driven by a pneumatic motor using continuous sliding mode as a servo pneumatic actuator driven by a pneumatic motor.

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볼스크류 선회형 가공장비의 설계 및 해석에 관한 연구 (A Study on the Analysis and Design for a Ball Screw Whirling Machine)

  • 이춘만;문성호;김은중
    • 한국정밀공학회지
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    • 제34권3호
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    • pp.173-178
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    • 2017
  • Recently, a high-precision ball screw is an essential part of high-speed machines. However, producing high-precision ball screws has been costly and time-consuming. Nowadays, a whirling machine is used to produce high-precision ball screws efficiently. Rotating multi-tips are used to turn the ball screw in the whirling machine. In this study, a structural analysis was performed by a finite-element method to develop a whirling machine. An improved model of the whirling machine was proposed by the analysis. In addition, a thermal analysis was performed to confirm the thermal stability. The results of the analysis can be applied in order to further develop the whirling machine.

고경도강의 나사선삭 (Ball Screw Cutting of Hardned Steel)

  • 황동환;박철우;김대은;이상조
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 1993년도 추계학술대회 논문집
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    • pp.37-41
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    • 1993
  • ball screw is a critical machine component which dictates the precison of a given machine tool. The conventional manufacturing method requires the heat treated ball screw to be ground to its final dimensions. This study looks into the the feasibility of replacing the grinding process with a simpler process, namely threading on NC lathe. The purpose is to reduce the capital investment as well as production time in the manufacture of ball screws. Ceramics and CBN cutting tools are compared with respect to their ability to machine hardened steel. It is shown that CBN tools can be successfully utilized to machine precision ball screws with superior suface qualities.

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가공최적화를 통한 볼 스크류의 소음성능 향상에 관한 연구 (A Study on the Improvement of Noise Performance by Optimizing Machining Process Parameters on Ball Screw)

  • 허철수;최종훈;김현구;신중호;류성기
    • 한국기계가공학회지
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    • 제10권1호
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    • pp.54-61
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    • 2011
  • Ball screw systems are largely used in industry for motion control and motor applications. But the problem of noise, which really perplexes us, is highly correlated with the quality in ball screw systems all the way. In this paper, machining process parameters were evaluated in respects of technique, business, produce and quality to verify which impact influences the noise most. In order to adjust and compare, two comparison groups were set with the present parameters bench mark. Different ball screws were produced as specimens for the noise tests. Through comparing the noise performance of different parameters in the machining process respectively, a group of optimized machining process parameters were obtained. Another noise test was proceeded to know how noise performance was improved by optimizing the machining process parameters. At last, surface roughness tests have been done to know how surface roughness improved by optimization. The improvement of surface roughness is the main factor influences the noise performances.