滾珠導螺桿之螺帽動態導程檢測系統研製

滾珠導螺桿、螺帽、鋼珠及回流管構成的系統，其主要功能可將旋轉運動換成線性運動，或將扭矩轉換為軸向反覆的作用力，為現今科技精密定位上不可或缺的元件。螺桿精度等級若屬於研磨級以上，製造商將提供累積導程誤差圖表，以期補償由旋轉換成直線位移在加工上所造成的誤差。然而，對於滾珠導螺桿之螺帽，至今仍無適合檢測其累積導程誤差之測量儀器。本論文目的即為發展一套自動化檢驗滾珠螺帽累積導程誤差之量測系統。類似於螺桿檢測的方法，旋轉待測螺帽，並將固定在交插滾子滑動台的細長槓桿伸入螺帽內部，槓桿前端為配合螺帽溝槽大小的滾珠探頭並附著於螺帽溝槽內，使探頭在螺帽旋轉下不斷地被拉入內部。透過市售高解析度的旋轉編碼器與自行研發的奈米解析度光學尺系統，可將旋轉角度換算成理想直線位移，並與實際前進的位移進行比對，自動化檢測滾珠導螺桿之螺帽的累積導程誤差。對於旋轉中的元件，其將經歷軸向之滑移、徑向偏心與角度的傾斜，進而造成量測系統誤差，因此必須先被消除與補償。本研究藉由旋轉主軸誤差數學模型的建立，並透過電容式位移計量測其誤差參數，首先消除了軸向滑移與角度傾斜對系統的影響；另外再透過壓電致動器結合自行設計的撓性絞鍊元件，藉由PID控制方法，將量測探頭保持與螺帽固定位置，相當於是直接補償了旋轉中螺帽徑向上的跳動，消除徑向偏心。完成之滾珠螺帽動態導程量測儀，將實際對市售之滾珠螺帽進行檢測，並提供滾珠螺帽累積導程誤差之實驗數據與圖表。

關鍵字

滾珠導螺桿之螺帽；主軸誤差量測；撓性絞鍊； PID控制

並列摘要

Ballscrew is a precision mechanical component serving to convert rotational motion to linear motion in a precision linear stage. The measuring system for the screw’s accumulative lead error can be found on the market. Up to now, however, there is no suitable measuring machine for accumulative lead error measurement of the nut. It is known that this error directly reflects the grade of the nut. This paper presents a developed automatic accumulative lead error measuring system for ballscrew nuts. Similar to the screw measuring system, the nut is clamped by a rotational stage and the probe ball is in contact with the groove of the nut. The probe is mounted on a cross roller table so that when rotating the nut the probe ball will be pulled by the groove wall and moved axially. A high resolution diffraction interferometer scale will read the linear movement of the probe to nanometer resolution. Combining the angular and linear motions the accumulative lead error can be realized. In practice, however, the nut will experience axial slip, radial run-out, and tilt during the motion. These spindle-like rotating induced errors have to be compensated in order to guarantee precise measurement results. Based on the derived theoretical model of axial slip, the axial runout could be measured by placing capacitive displacement sensors to acquire the translational displacement of the spindle and the angle of the pitch. Furthermore, a sensor gap measurement system associated with a servo piezoelectric actuator stage has been developed for the purpose of radial runout compensation. A microprocessor based PID controller is established to real-time adjust the probe ball’s vertical position so as to remain contact with the nut groove. Experimental results will show the applicability of this developed measuring system.

並列關鍵字

Ball screw nut ； Spindle metrology ； Flexure hinge ； PID control

參考文獻

【2】Gadelmawla E.S. A novel system for automatic measurement and inspection of parallel screw threads. Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture 2004; 218:545–56.

【3】Huang Hsueh-Liang, JyweWen-Yuh, et al. Development of a novel laser-based measurement system for the thread profile of ballscrew. Optics and Lasers in Engineering 2010; 48:1012–8.

【5】R.J. Hunsicker, J. Patten, A. Ledford, C Ferman, et al. Automatic vision inspection and measurement system for external screw threads. Journal of Manufacturing Systems 1994; 13(5):370-384.

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【13】D.S. Guevarra, A. Kyusojin, Isobe, Hiromi, Y. Kaneko, Development of a new lapping method for high precision ball screw (2nd report): design and experimental study of an automatic lapping machine with in-process torque monitoring system, Precision Engineering 2002; 26(4):389–395.

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滾珠導螺桿之螺帽動態導程檢測系統研製

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