液靜壓主軸應用於皮帶驅動式磨床之設計與性能分析

Design and Performance Analysis of Hydrostatic Spindle Applied to Belt-driven Grinder

陳詩涵(Shih-Han Chen)

指導教授 ： 林士傑

國立清華大學/工學院/動力機械工程學系/碩士(2021年)

摘要

液靜壓軸承具有較佳的承載力、剛性和迴轉精度等特性，被廣泛應用於精密磨削工具機。對於皮帶驅動式磨床來說，其加工精度容易受到皮帶張力和磨削力的影響，故本研究將針對搭載於磨床機構之液靜壓主軸進行設計，預期利用液靜壓性能改善主軸振動問題以提升整體加工水準。
本研究透過雷諾方程式和有限差分法等基礎理論的推導，以數值分析方式建立模擬程式，可用於評估軸頸軸承和止推軸承之油膜壓力分布、承載力、剛性以及流量。並參考市面上磨床機構的規格與工作需求，設計出一液靜壓主軸，其特點為軸承各油腔將採用不一致的孔口節流器配置，以預先提供固定負載，來平衡主軸受到初始皮帶張力所導致的偏心。從性能模擬結果得知，此設計所能提供的承載力範圍較大，且在較大偏心率時仍能維持較佳的剛性表現。
最後完成液靜壓主軸的加工與組裝，接續進行靜態性能測試，確認節流器有達到預期節流與補償作用，並探討實際節流器流阻、油膜厚度或油品性質的影響，對模擬程式予以修正與優化，使其能更符合真實情形，將有利於液靜壓性能的預測。經由以上結果驗證本研究之主軸設計與性能模擬程式的可行性，也體認到液靜壓主軸對製造精度與油品性質要求的重要性。

關鍵字

液靜壓軸承 ； 皮帶驅動式磨床 ； 孔口節流器

並列摘要

Hydrostatic bearings had been characterized with low friction, high load capacity, high stiffness, high precision, high damping, and long operation life. These advantages make them extensively used in high precision grinding machining. For belt-driven grinder, the machining accuracy may be affected by belt tension and grinding force. The purpose of this research is to design a hydrostatic spindle to be used in a belt-driven grinder. It is expected that the use of hydrostatic spindle can improve the performance of the machine.
In this study, the fundamental theories for hydrostatic system were reviewed. Based on the Reynolds equation and the finite-difference method, simulation program was developed to evaluate the pressure distribution, load capacity, stiffness, and flow rate of the hydrostatic system. Based on the simulation results and specifications provided, the dimensions of the hydrostatic spindle were determined. It should be noted that, in this study, the orifice restrictors were purposely selected such that the spindle should be located around the center of the bearing when constant belt tension was applied. Finally, all components were machined, and the hydrostatic spindle was assembled. The performance of the hydrostatic spindle was test experimentally. The test results were closed to those had been studied in simulations.

並列關鍵字

Hydrostatic bearing ； belt-driven grinder ； orifice restrictor

參考文獻

[1] Taniguchi, Norio (1983). Current status in, and future trends of, ultraprecision machining and ultrafine materials processing. Tokyo science university, Japan.

[2] 台灣區工具機暨零組件工業同業公會(2019)。2018年度工具機進出口分析。工具機零組件雜誌。檢自：TMBA (Oct., 2020)

[3] W. B. Rowe (2012). Hydrostatic, Aerostatic, and Hybrid Bearing Design. Elsevier, Amsterdam.

[4] R. Bassani, B. Piccigallo (1992). Hydrostatic Lubrication. Elsevier, Amsterdam.

[5] Hydrostatic spindles. HYPROSTATIK Schönfeld GmbH, Germany. Retrieved from https://hyprostatik.de/en/products-service/hydrostatic-bearing/ (Jun., 2020).