Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/35691
標題: 秤重機負荷元之最佳化設計
Optimal Design of Load Cell of Weighing Machines
作者: 林峰緒
Lin, Feng-Hsu
關鍵字: Load Cell;負荷元;Finite Element Analysis;Optimal Design;有限元素法;最佳化設計
出版社: 生物產業機電工程學系
摘要: 
A new design of load cell had been developed in this study. Load cell is the major part of weighing machines. The weighing machines are used in many areas, such as drying center, and grain husking factories. Accuracy is the first concern for weighing machines. In general, an ideal load cell should be lightweight, small size, and sensitive. However, every load cell is only accurate within some range. C-type and S-type load cells are used quite extensively. We propose to design a G-type load cell. It can measure in two phase depending on whether contact happens between two components or not. In the first phase, no contact between two components happens and the measurement can be treated as in light loading. In the second phase, contact between two components happens and the measurement can be treated as in heavy loading.
I-DEAS was used to analyze and design the G-type load cell. According to the result of FEM simulation, prototype of G-type load cells were made and tested. The strain of the G-type load cell under certain loads was measured and recorded. The relation between load and strain was calibrated to verify the result of FEM simulation and tested.
According to the result, for the load cell with the width of 20, 30, and 40 mm, the predicted models have been developed. The maximal relative errors are 2.97 %, 0.72 %, and 0.0 % during light loading as well as 8.49 %, 1.14 %, and 0.69 % during heavy loading. According to the results of Parameter Study, the model with cutting hole of a diameter of 7.0 mm in Part A and 4.0 mm in Part B has the best sensitivity. The mass of the model without steel cylinder is 0.253 kg. This model is the optimal design of the study.

本研究進行新型負荷元之設計,負荷元為電子磅秤之主要構件,電子磅秤廣泛應用在農業上,如:乾燥中心、碾米廠等秤重作業。磅秤首要特性是準確度。理想的負荷元應具有簡單的幾何尺寸,重量或體積輕小化、靈敏度高等。一般負荷元必須依照不同的負荷範圍選用不同的規格,因此其量測僅侷限在一定範圍,這類的負荷元外形有C型及S型等。本研究設計一種外形似G型的負荷元,可經由兩構件相互接觸與否產生兩區段之量測範圍:第一段適用於輕負荷,接觸之後的第二段用於重負荷。
本研究以I-DEAS軟體之分析模組與最佳化模組進行G型負荷元結構分析與外形最佳化設計,求得最佳的結構形體。根據電腦數值模擬結果,製作負荷元雛形實體模型,進行負載試驗。藉應變規量測所產生之應變估算負載,驗證軟體分析結果。
本研究設計之G型負荷元,藉由應變規電壓信號可以估算負載的大小,經試驗量測後,三種寬度(20、30、40 ㎜)之負荷元在輕負荷部分,最大相對誤差分別為2.97 %、0.72 %、0.0 %,在重負荷部分,最大相對誤差分別為8.49 %、1.14 %、0.69 %。經Parameter Study,A部分挖孔直徑7 ㎜、B部分挖孔直徑4 ㎜時得到之靈敏度最好,負荷元質量不含頂柱為0.253 kg,為G型負荷元之最佳化設計。
URI: http://hdl.handle.net/11455/35691
Appears in Collections:生物產業機電工程學系

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