電子連接器密封性能檢視

Abstract

本論文呈現一套分析應用於音響設備之二合一連接器矽橡膠墊圈密封性能之系統化流程。當音響設備之背蓋放置於設計之位置時，背蓋將矽橡膠墊圈壓迫於背蓋與二合一連接器之間，將背蓋與二合一連接器間之縫隙密合，隔絕音響設備內外，內部形成一密封腔體。然洩漏將於經過一段時間後發生，因此以有限元素分析矽橡膠墊圈之受力情形與歷時變化。分析過程將矽橡膠墊圈材料之超彈性質與應力鬆弛現象納入考量，以穆尼-黎弗林與普羅尼級數描述材料受力行為進行數值分析，而此些材料模型之參數係藉由單軸壓縮鬆弛實驗與單軸拉伸鬆弛實驗，並採用合宜描述矽橡膠材料之數值進行參數迴歸。矽橡膠墊圈之密封性能將由其與二合一連接器兩者間之接觸應力大小評估，經由有限元素分析檢視矽橡膠墊圈承受三種下壓量對於接觸應力之影響，亦考量其歷時變化情形。針對二合一連接器進行密封實驗所得之壓力損失百分比，並根據矽橡膠墊圈關鍵元素於承受下壓量0.2mm條件下之接觸應力與時間關係，代入自行提出洩漏率預測模型進行參數迴歸，接續預測其餘較大下壓量之相對應壓力損失百分比。針對另一採用相同墊圈材料之耳機座連接器，將上述所得之模型參數代入預測其壓力損失百分比，與相對應密封實驗所得進行比較，進一步驗證此流程之合宜性。

Systematic procedures are developed to investigate sealing characteristics of a so-called 2-in-1 electronic connector applied to audio equipments in the present study. A silicon elastomer gasket located between a plastic housing of the connector and a back-cover of the audio equipment will be squeezed to provide the sealing function when the back-cover is displaced at a designated position. Gas is subsequently pumped into the confined chamber up to the specific pressure while the internal pressure is continuously monitored. Leakage indicated by the pressure loss percentage however could occur through the gasket after a certain period. A finite element analysis is carried out to explore the time-dependent response of the silicon elastomer gasket. The Mooney-Rivlin and the Prony series constitutive models are adopted in the numerical simulations to account for the hyperelasticity and the stress-relaxation behaviors of the gasket material, respectively. Required parameters of these mathematical models are evaluated based on experimental measurements of the specified silicon elastomer specimen subjected to both the uniaxial compression-relaxation and tensile-relaxation loading conditions. Sealing performances can then be assessed by implementing variations of the contact stress of the critical point of the gasket over the relatively long period into a proposed leakage rate prediction model. Pressure loss percentages in the chamber based on the numerical calculations agree well with those based on the corresponding experiments. In order to validate the appropriateness of the current systematic procedures, the pressure loss percentage of an enclosed cavity of an audio jack connector is also evaluated here.