含人字形溝槽液體動壓頸軸承應用於風扇之 振動與噪音分析

Abstract

本研究以實驗分析含人字形溝槽之液體動壓頸軸承應用於離心散熱風扇的振動與噪音特性。軸承溝槽參數設計以前人對動壓軸承溝槽尺寸之數值模擬文章所提出最佳化設計數據作為參考，設計並加工出數種不同溝槽的軸承，藉此分析不同溝槽參數對於振動與噪音之影響。實驗部分將以壓電式加速度規來量取風扇運轉時所產生的振動，並以振動信號作為穩定性的參考，此外以提供之電源功率來觀察轉子因與潤滑油膜摩擦所散失的能量。噪音實驗部分於半無回響室中量取風扇運轉時所產生之噪音，並由聲音壓力位準以及聲音品質兩種角度來評判軸承在噪音上的表現。 實驗結果顯示，軸承的穩定性在溝槽深度比為1、溝槽角度40度、溝槽數8時為最佳。而風扇的噪音和軸承的徑向振動量有正相關，建議將軸承的深度比設計在1.5~2之間以降低風扇之噪音量。

The objective of the study is to investigate the vibration and noise characteristics of hydrodynamic journal bearing with herringbone groove use for centrifugal fan. The design parameters of groove refers to the paper which is about the optimization design of groove. The bearings are made with different types of grooves for the purpose of analyzing the influence of deign parameters on vibration and noise. The vibration measured by piezoelectricity accelerometer will be the reference of the stability of bearing. And the power loss made by the friction between shaft and liquid-lubricated film will be observed by the supply power of fan. The fan noise is measured in the half anechoic chamber, and judge the noise performance from sound pressure level and sound quality. The results show that the optimum groove parameters based on the stability criteria are: the groove ratio is 1, the angle is 40 degree, and the numbers of grooves are 8. And the noise of fan correlates to the axial vibration of fan, so the suggestion of groove depth ratio for reducing the noise is 1.5~2