高轉速光碟機噪音減低之可行性研究

The Feasibility Study on Noise Reduction of Optical Memory Devices under High Rotation Speed

林正義(Cheng-Yi Lin)

指導教授 ： 張 英 俊

大同大學/工程學院/機械工程學系所/碩士(2004年)

摘要

摘要
CD-ROM光碟機發展至今已相當成熟，因為承載盤要能隨意開啟，所以機殼無法密閉情形下，當光碟機高速運轉時無法完全阻隔空氣動力噪音(Aerodynamic noise)，且驅動軸與碟片間也需要有間隙(clearance)，碟片會因間隙產生不平衡，則該不平衡量會引發振動及噪音。如何降低碟片振動及減低噪音是本論文主要研究項目。
本論文利用實驗方法確定開孔板直徑對噪音的降低有一定的成果，以孔越小越好，且有空氣層效果佳。光碟機Turntable尺寸及Turntable上煞車橡膠的摩擦係數和碟片振動之關係，確定主軸馬達上的大尺寸Turntable在10200rpm高速旋轉能有效減低碟片振動噪音及煞車橡膠摩擦係數會影響光碟片穩定度，高摩擦係數在1700Hz的harmonic值比低摩擦係數降低3.7dBA。承載盤封閉的harmonic值在1700Hz會比正常承載盤低8dBA，可知承載盤的讀寫頭開孔會對高速氣流造成影響，因而增加碟片旋轉的風切聲。本論文並利用CAD軟體建立碟片模型以及用FEM TOOLS進行不同大小固定面積的碟片模態分析，並以實驗方法找出碟片自然頻率。

關鍵字

噪音 ； 光碟機

並列摘要

ABSTRACT
The CD-ROM has been maturely developed till now. Because the turntable must be opened at will, thus the body shell cannot be well sealed. Under the rotation of high speed, the CD-ROM cannot thoroughly insulate the aerodynamic noise. Also, it is required for clearance between the diving axis and disks and the imbalance will bring about vibration and noise accordingly. How to reduce the disk vibration and noise will be the main issue for this dissertation.
This dissertation is adopted with the experimental methodologies to assure the effective reduce for the vent board diameter affecting onto the noise. The smaller vent will be better to assure of excellent air layer effect. As for the correlation between the turntable dimensions and the friction coefficient of the braking rubber on the turntable of CD-ROM, we can confirm the large-dimensioned turntable onto the spindle motor, it can effectively reduce the disk vibration noise paced at 10200rpm and the friction coefficient of braking rubber will affect the stability of dick. The high friction coefficient under the harmonic value of 1700 Hz, will be lower than that of lower friction coefficient by 3.7dBA. The closely sealed turntable with the harmonic value rated at 1700Hz will be lower than that of normally conditioned turntable by 8dBA. We can know that the optical reader vent of turntable will affect the hi-speed air flow and thus it will increase the wind shearing noise of disk rotation. This dissertation is also adopted with the CAD software to create the disk models and also applied with the FEM TOOLS to perform the disk modal analysis of various fixed areas. Also, we can explore the natural frequency of disk.

並列關鍵字

CD-ROM ； Noise

參考文獻

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