寶特瓶直線式吹瓶機之開關模機構是由一組凸輪機構和連桿機構所組成,由馬達帶動凸輪旋轉,進而帶動從動件進行搖擺運動,並藉由連桿機構驅動兩側開關模進行往復直線運動。凸輪機構在高速運轉時,會因為拘束彈簧之預壓力不足,造成從動件在降程尾端會產生跳動(flopping)現象,為了消除此一現象,本論文取消彈簧元件,因此必須採用共軛凸輪之設計。本論文運用解析法求得第一片凸輪輪廓與作用時之壓力角,壓力角作為凸輪系統設計之重要參考參數,壓力角越小越好,搖擺從動件的壓力角不可大於45O。有關共軛凸輪之機構設計,本論文提出共軛凸輪設計時的限制條件,並利用坐標轉換公式,設計出第二片凸輪,兩片凸輪只是旋轉了特定角度,凸輪輪廓並不會改變。另外,由於伺服馬達轉速甚高,要驅動凸輪必須進行減速;因此,本論文最後進行整合共軛凸輪系統與齒輪減速機之整合設計,使之成為一個 ”凸輪-齒輪箱” ,作為未來開發 ”凸輪-齒輪箱” 的雛型機的參考依據。
The open/close mode mechanism is cam-linkage mechanism which is consisting of a cam mechanism and a linkage. Motor drives cam rotate and follower oscillate. Then, cam follower drives linkage move and its open/close mode have reciprocating linear motion. The follower will flop and jump in the end of descending due to the reason of lack of spring preload. In order to eliminate this phenomenon, this thesis cancels spring element, and therefore must use the conjugate cam design. Using analytical method, this thesis obtains profile of 1st cam disk and pressure angle. Pressure angle is an important parameter of cam mechanism and cannot larger than 45O. Here, we propose the design constraints of conjugate cam mechanism. According to the design constraints, Using coordinate conversion formula, profile of 2nd cam disk is obtained. The two cam disks are totally same only rotate a specific angle. In addition, due to the high speed of the servo motor, the gear reducer is required to reduce the speed of servo motor. Therefore, this thesis integrates conjugate cam mechanism and gear reducer to be a “cam-gearbox”. The engineering design of “cam-gearbox” can be the reference while manufacturing its prototype.