具三弧面中間桿的平移式從動件之盤形凸輪機構的設計

The Design of Disk Cam Mechanisms with a Translating Follower Having an Added Triple-Arc-Faced Intermediate Link

陳寶生(BAO-SHENG CHEN)

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(2014年)

https://doi.org/10.6843/NTHU.2014.00192

摘要

本文提出一種改良式從動件，亦即在習用的平移式從動件與凸輪之間加入一個具有三弧面特徵的中間桿件。此具有三弧面中間桿的平移式從動件會與凸輪輪廓產生三個對應的接觸位置，並分別接觸於兩組凸輪輪廓曲線。文中首先針對習用的平移式滾子從動件、平面從動件以及凹面從動件之盤形凸輪機構進行運動學、接觸力以及接觸應力的分析。接著提出一套解析法來設計具雙弧面中間桿的平移式從動件之盤形凸輪機構，此具有雙弧面中間桿的平移式從動件會與凸輪輪廓產生兩個對應的接觸位置，以分擔元件所需承受之正向接觸力。然而，該凸輪機構仍需藉由回位彈簧之鎖合力以維持從動件與凸輪間的接觸關係。因此，在適當的參數設定下，相較於習用的平移式滾子從動件，加入雙弧面中間桿能讓從動件與凸輪間之接觸應力極值降低約70.9% ~ 75.9%；相較於習用的平移式凹面從動件，這種加入雙弧面中間桿之從動件則僅能讓從動件與凸輪間之接觸應力極值降低約5.5% ~ 21.8%。

　　本文最後提出具三弧面中間桿的平移式從動件之確動式面凸輪機構與帶肋凸輪機構的設計。三弧面從動件與凸輪接觸於兩組相對應的輪廓曲線並產生三個接觸位置以分擔元件所需承受之正向接觸力。由於該凸輪機構是為溝槽式以及凸緣式的設計，無須使用回位彈簧即可維持從動件與凸輪間的接觸關係。因此，在適當的參數設定下，相較於習用的平移式滾子從動件，加入三弧面中間桿之盤形凸輪機構可使從動件與凸輪間之接觸應力極值降低約81.5% ~ 86.9%；相較於習用的平移式凹面從動件，這種加入三弧面中間桿之盤形凸輪機構則可使從動件與凸輪間之接觸應力極值降低約39.9% ~ 57.7%。

關鍵詞：三弧面、槽凸輪、帶肋凸輪、凸輪連桿機構、凸輪輪廓、接觸應力。

關鍵字

三弧面 ； 槽凸輪 ； 帶肋凸輪 ； 凸輪連桿機構 ； 凸輪輪廓 ； 接觸應力

並列摘要

This research proposes a modified arrangement of the common translating follower disk cam mechanism in which an extraneous triple-arc-faced intermediate link was added between the cam and the translating follower. Two of the three arc faces on the intermediate link would be in contact with one set of profile of the disk cam, and the third one would be in contact with another. In order to justify the improvement could be made by replacing the common translating follower with the triple-arc-faced follower, studies involving kinematics, statics, dynamics and contact stress analysis of the common translating followers were conducted at first. Then an analytical approach for designing disk cam mechanism with a translating follower having an added dual-arc-faced intermediate link was proposed. Although there were two contact positions, the requirement for the return spring still caused high contact stresses on the cam system. Therefore, in comparison to the common translating roller follower, the contact stress could be reduced by 70.9% ~ 75.9% by using the dual-arc-faced follower; in comparison to the concaved face follower, the contact stress could be only reduced by 5.5% ~ 21.8%.

In the end of this research, an analytical approach for designing groove cam mechanism and rib cam mechanism with a translating follower having an added triple-arc-faced intermediate link was proposed. The triple-arc-faced intermediate link was in contact with two set of cam profiles at three different positions. Therefore, forces acting on the machine elements could be dispersed by the three contact positions. Furthermore, due to the groove cam and rib cam design, there was no requirement for the return spring. As a result, by using the triple-arc-faced follower, the contact stress could be reduced by 81.5% ~ 86.9% in comparison to the common translating roller follower; 39.9% ~ 57.7% in comparison to the translating concaved face follower.

Keywords: Triple-arc faces, groove, rib, cam-modulated linkage, cam profile, contact stress.

並列關鍵字

Triple-arc faces ； groove ； rib ； cam-modulated linkage ； cam profile ； contact stress

參考文獻

[18] 許家榮，2012，加入具雙凹面中間桿的平移式從動件之盤形凸輪機構的設計，碩士論文，國立清華大學動力機械工程學系，新竹市。

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