本文提出一種嶄新的具有中間桿的搖擺式從動件之盤形凸輪構造,該中間桿件包含有三弧面並以軸樞與端接器相聯接。該凸輪機構具有兩組相對應的輪廓曲線,且凸輪輪廓可以為溝槽式或是凸緣式的設計。此新穎的搖擺式從動件構造首次可隨時與凸輪保持接觸的三個接觸點,從而得以相對降低凸輪與中間桿件間的正向接觸力。因此,相較於習用的單點接觸之搖擺式從動件,使用加入三弧面中間桿之從動件可降低作用於凸輪與中間桿件間的接觸應力。本研究提出一套解析法來設計額外加入三弧面中間桿的搖擺式從動件之盤形凸輪機構。鑑於實務上的考量,本文建議在凸輪與中間桿件間施加預壓負荷以避免產生間隙。根據本研究的內容與其所獲的結果顯示,相對於使用滾子從動件,若採用新式的從動件,最大接觸應力之降幅約59.9% ~ 81.5%;相對於使用平板式從動件,最大接觸應力之降幅約23.6% ~ 64.7%;相對於使用凹面從動件,最大接觸應力之降幅約6.9% ~ 57.1%。
This research proposes a novel configuration of disk cam mechanism with an intermediate link mounted between cam and oscillating follower. The intermediate link is made triple-arc-faced and pivoted on end-effector. The driving cam has two sets of profiles, which can be either grooved or ribbed form to guarantee the positive-drive motion. Such a configuration of cam mechanism is able, for the first time, to theoretically realize the triple-point contact between cam and oscillating follower. Having multiple contact points yields much lower contact forces exerted between the mating cam and intermediate link. Therefore, the contact stress on cam contour can be correspondingly diminished by a certain amount in comparison with using common oscillating follower in contact with cam at one point. An analytical approach is addressed to illustrate how to synthesize such cam mechanism. For the sake of practicality, the preload is suggested for the elimination of internal clearances between the triple-arc-faced intermediate link and the cam. The results of this research indicates that using the triple-arc-faced follower yields a reduction of the contact stress by 59.9% ~ 81.5% in comparison with using the oscillating roller follower; 23.6% ~ 64.7% in comparison with using the oscillating flat-faced follower; 6.9% ~ 57.1% in comparison with using the oscillating concave-faced follower.