| 摘要: | 為滿足縫紉衣物時布料不同材質和厚度所產生多樣的縫紉需求，縫紉機藉由送布機構設計達到不同的送布軌跡，以實現所需要的各種送布效果。本論文提出以機械方式達成可變送布軌跡的新型送布機構。此機構可以在不變更現有機台架構的情況下，以凸輪機構取代原機構曲柄搖桿機構，如此可以透過更換不同的凸輪盤來實現不同的送布軌跡，以滿足不同的縫製需求。
為建立完整的設計方法，在論文中首先利用模組機能展開方法分析現有工業用拷克機主要工作桿件，將達成同功能的零件視為同一模組，並完成分類。再將達成送布操作之送布模組和送布調整模組，進一步利用詮釋結構模式方法分析送布機構所有零件。將桿件連接具有高度關聯性視為一個模組，以了解各模組對於送布軌跡的影響。確認可將曲柄搖桿機構由搖擺式滾子盤形凸輪機構取代。
為能計算送布軌跡，本研究利用向量迴路法建立機構各桿件的運動位置分析模型。而在設計新型送布機構的送布軌跡時，必須滿足原機構的限制條件，包含送布和針桿的運動時序關係以及送布桿件擺動角度的限制。因此以最少的資料點定義方式以貝茲曲線生成送布軌跡，以能夠在限制條件下產生連續、平滑且曲率連續之軌跡曲線。本研究同時考量現有機台的空間限制以及凸輪製造上限制，建立由送布軌跡決定凸輪機構相關參數之計算模式以及凸輪盤輪廓合成方法。
為了驗證設計新型送布機構的正確性，在研究中亦以原軌跡、三種特殊送布軌跡為例進行設計與計算對應的凸輪輪廓。並以市售機構模擬分析軟體SAM進行模擬驗證。另一方面，亦討論調整機構之調整送布量後對軌跡的影響。結果顯示本研究所建立之設計方法可行，並能達成各種送布軌跡之目標。
本論文所提出新型送布機構的構想與完整從模組化分析、機構分析、送布軌跡設計到凸輪盤合成等設計方法，亦可延伸於其他縫紉機台，協助國內縫紉機產業之相關機台功能升級。
;To meet the diverse sewing requirements arising from various fabric materials and thicknesses, sewing machines utilize specially designed feed mechanisms to achieve different feeding trajectories for the desired sewing effects. This paper proposes a novel feed mechanism capable of achieving variable feed trajectories through mechanical means. This mechanism can replace the original crank-rocker mechanism with a cam mechanism, without altering the existing machine structure. Therefore different feed trajectories are able to be achieved by changing the cam disc, to meet different sewing needs.
To establish a comprehensive design methodology, the main working components of existing industrial overlock machines are at first analyzed using the modular function deployment method. Components performing the same function are classified into the same module. The feed module and feed adjustment module, responsible for the feeding operation, are further analyzed using the interpretive structural modeling method to understand the impact of each module on the feed trajectory. The feasibility of replacing the crank-rocker mechanism with a cam mechanism featuring an oscillating roller is confirmed.
To calculate the feed trajectory, this study uses the vector loop method to develop a motion position analysis model for each component of the mechanism. When designing the feed trajectory of the new feed mechanism, it is essential to meet the constraints of the original mechanism, including the motion timing relationship between the feed and needle bars, as well as the swinging angle constraints of the feed components. Therefore, Bezier curves are used to define the feed trajectory with the minimum number of data points, ensuring the generated trajectory is continuous, smooth, and curvature-continuous under the given constraints. Considering the space limitations of the existing machine and the manufacturing limits of the cam are also considered in the study. A calculation model for determining the cam mechanism parameters based on the feed trajectory and synthesizing the cam plate profiles is established in the study.
To validate the accuracy of the new feed mechanism design, the corresponding cam profiles for the original trajectory and three specific feed trajectories are designed and calculated in the study. These designs are verified through simulations using the commercial SAM software. Additionally, the impact of feed amount adjustments on the trajectory is discussed. The results demonstrate the feasibility of the proposed design methodology, achieving the intended feed trajectories.
The novel feed mechanism concept and the complete design methodology, from modular analysis and mechanism analysis to feed trajectory design and cam plate synthesis, presented in this paper can be extended to other machines. This can aid in upgrading the functionality of related equipment in the domestic sewing machine industry. |
