變速平移凸輪機構之機械誤差分析

Analysis of Mechanical Errors in the Varying-Velocity Translating Cam Mechanisms

李柏賢(Bo-Sian Lee)

指導教授 ： 吳隆庸

國立清華大學/工學院/動力機械工程學系/碩士(2011年)

摘要

以瞬心向量法可求得變速平移凸輪輪廓、壓力角、曲率半徑與運動函數，再利用運動係數的概念可求得另一衝程之運動函數。以凸輪輪廓、壓力角與輪廓曲率半徑的關係將等效連桿分為四個區段，分別討論各區段中設計參數與輪廓尺寸的機械誤差分析。當選定參數尺寸時，選擇極值較小之速度函數，則可降低輸出誤差極值；將曲柄尺寸減小或耦桿尺寸增加可獲得較好之傳力效果。由敏感度分析了解設計參數與輪廓尺寸對輸出誤差的影響程度相等，表示設計參數與輪廓尺寸的公差設定皆很重要。推導輸入扭矩與衝壓力的關係，以做為選擇馬達的參考。

關鍵字

變速平移凸輪 ； 等效連桿 ； 機械誤差分析 ； 敏感度分析

並列摘要

By applying the velocity instant center concept and vector loop equations, for a varying-velocity translating cam mechanism, the cam profile, the pressure angle, the radius of curvature of the cam profile and the motion program of the follower can be derived. Then the motion program of the return stroke of the follower can be obtained by means of the application of kinematic coefficients. According to the cam profile geometry of each region, the varying-velocity translating cam mechanism has four different equivalent linkages. Accordingly employing the equivalent linkage method, the kinematic errors of the follower caused by the deviation in each design parameter of the mechanism can be derived. If every design parameter of the mechanism has been specified, choosing a motion program that has a lower velocity value may reduce the mechanical error of the follower output. Additionally, the transmission effect can be improved by either decreasing the length of the crank or increasing the length of the coupler link. According to the sensitive analysis, the variation of each design parameter and that of the cam profile dimension has almost the same effect on the output motion error, and thus their tolerances are nearly equal in importance. For reference of choosing a motor, the relation between the input torque and the press force is also derived.

並列關鍵字

Vary-velocity translating cam ； Equivalent linkage ； Mechanical error analysis ； Sensitive analysis

參考文獻

[1] 三星科技股份有限公司網頁，http://www.sanshing.com.tw/。

[16] 張文桐，平面凸輪機構之機械誤差分析及其應用，博士論文，國立清華大學動力機械工程學系，新竹市，2007年，37-109頁。

[17] 彭繼增，銷子輪機構之設計及機械誤差分析，碩士論文，國立清華大學動力機械工程學系，新竹市，2010年，23-69頁。

[20] 李韶華，凸輪連桿組合式衝床機構之設計，碩士論文，國立清華大學動力機械工程學系，新竹市，2009年，84-87頁。

[5] Rothbart, H. A. (Eds.), Cam Design Handbook, McGraw-Hill, New York, 2004, pp. 285-301.