The Multi-Criteria Optimum Design of the Pull Down Mechanism on Lift Cabinet

[[abstract]]時代在進步，人類生活模式及習慣也跟著改變。隨著人們的消費能力提升、購買慾望也相對增加，但因人口都市化與空間結構之變遷，使得每個人所能分到的空間卻是越來越小。以居家為例，能收納物品的空間除一般儲櫃以外，人們開始著墨於室內較高空間的運用，於是高吊式升降置物架遂孕育而生。此類升降置物架，一般設計於150公分以上空間，作動時櫃體向外拉出，利用連桿機構產生下降功能，再配以緩衝裝置及拉力彈簧使其具備防撞及省力的效果。置物架雖改善了取用的方便性，但要達到更高的方便性卻仍存在許多問題，其中當置物架因升降時的高低差及重量承載大小不同，可能產生過大撞擊；另外則是承載重量到達一定程度，若欲將置物架復位，則需要施以蠻大力量才能達成，要省力又要防撞擊，期間產生了設計上的衝突，因為要省力就要以拉力彈簧輔以拉提力量，惟此力量過大又會使復位產生很大撞擊，須加裝緩衝裝置才能舒緩。針對其間設計上欲達到衝突目標：省力及防撞擊，本研究利用田口品質實驗法，參考穩健多目標最佳化原理，針對一原始設計之尺寸的櫃體，以彈簧及緩衝裝置位置為參數，進行機構穩健化設計，並依新的設計尺寸以多體動力學模擬軟體分析其動態特性，及利用有限元素分析軟體進行桿件受力分析，結果顯示依本研究的方法，找出的穩健設計置物架的總碰撞力降低了47 78%，復位力提升了0 79%，本研究所提方法可延伸運用到各類高吊櫃機構，在初步設計完成後，得到更佳的設計參數。[[abstract]]The life style and habit of people have been changed currently Along with the promoting of spending power the desire of buying is also increased Due to the change of the population and spatial structure for urbanization the space could be assigned for each person is getting smaller and smaller As an example of home life except the normal stored cabinets people begins to dwell on the higher indoor space The layout of hoist cabinet for equipping above 150 cm is developed The lift cabinet has to be pulled out when used and drops down by the furniture of mechanism in harmony with the pulling spring and buffer Although the device improves our life to be convenient it still exists some problems When the higher load spring is used it provides higher pulling force but may result in higher impact Saving effort and impact protect is going to be contradiction in design In accordance with the taguchi experiment method and the multi-objective of design function the robust multi-criteria optimization approach by taguchi method theory is used in this study With dfferent spring and damping positions of the original cabinet dimensions the robust design is achieved The dynamic characteristics are analysed by multibody dynamics simulation software for the newly design also the ANSYS software is applied to analyse the force response of linkages The result showed that the total impact force is reduced by 47 78% and lift force is saved by 0 79% The methods propose in this study could be extended to various types of high wall cabinets after the completion of the preliminary desig