熱親和概念於臥式液靜壓工件主軸設計之應用

Application of Thermo-Friendly Concept in Horizontal Hydrostatic Spindle Design

楊詠媛(Yong-Yuan Yang)

指導教授 ： 宋震國

國立清華大學/工學院/動力機械工程學系/碩士(2019年)

摘要

在液靜壓軸承系統中，熱變形所帶來之熱致誤差於所有精度誤差中占有相當程度的比例，因此本文針對一套具有高負載、高剛性、低轉速且高定位精度特性之臥式液靜壓工件主軸，探討其溫度對迴轉精度與熱變形之影響，同時引入Okuma公司所提出之熱親和概念，以降低熱變形導致之誤差問題。
在理論方面，本文首先建立液靜壓軸承設計之基本理論，並針對定壓式液靜壓對向墊軸承之構型，探討在不同之油腔內部壓力與供給壓力比值下，油膜剛性與承載力之性能表現；此外，本文著重於液靜壓軸承系統之熱致誤差解析，藉由計算液靜壓主軸運作中所產生之熱源，透過熱固耦合模型，分析整機之穩態溫度分布以及結構變形狀況，並應用熱親和概念進行構型修改，以降低熱致誤差。
在實驗方面，本文使用一套臥式液靜壓工件主軸，量測其於定轉速下，不同旋轉時長之迴轉精度表現，以及不同轉速下，主軸前端之軸向位移量並加以分析，並與數值模擬相互驗證；此外，建立HTM（Homogeneous Transformation Matrix）誤差矩陣，將誤差指標化，以利系統整合之誤差評估；最終期望透過機構構型之優化，以提升液靜壓軸承之精度表現。
關鍵字：臥式液靜壓工件主軸、熱致誤差、熱固耦合、熱親和

關鍵字

臥式液靜壓工件主軸 ； 熱致誤差 ； 熱固耦合 ； 熱親和

並列摘要

The error caused by thermal deformation accounts for the vast majority of accuracy error in hydrostatic bearing system. Thus, this study investigated a set of horizontal hydrostatic spindle to identify the impact of temperature rise on thermal deformation as well as rotation accuracy. Meanwhile, “Thermo-Friendly Concept” proposed by OKUMA company was employed to reduce the error brought by thermal deformation.
The fundamental theory of hydrostatic bearing design was first built. The focus is on investigation of oil-film stiffness and load-capacity performance under various ratios of pocket pressure and supply pressure for opposed-pad hydrostatic bearing in a constant pressure system. Furthermore, this study analyzed the thermal error in hydrostatic bearing system through identifying the heat sources and calculating the heat generated during spindle rotation. By using thermal-solid coupling model, the steady-state temperature field and structural deformation could be obtained. Lastly, “Thermo-Friendly Concept” was applied to decrease thermal error through modifying the structure of the hydrostatic spindle.
In experiment, a set of horizontal hydrostatic spindle was studied by analyzing the items below: (i) rotation accuracy of different rotation durations at fixed speeds, and (ii) axial displacement of spindle nose at different speeds. Moreover, to evaluate error at system integration state, the error matrix expressed by homogeneous transformation matrix was established to signify errors. Finally, the accuracy of hydrostatic bearing via modifying the structural configuration was improved as expected.
Keywords: horizontal hydrostatic bearing, thermal error, thermal-solid coupling, Thermo-Friendly Concept.

並列關鍵字

horizontal hydrostatic bearing ； thermal error ； thermal-solid coupling ； Thermo-Friendly Concept

參考文獻

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