【作者】 吴晓雨；

【导师】 倪俊芳；

【作者基本信息】 苏州大学 ， 机械工程（专业学位）， 2019， 硕士

【摘要】 电动工具是使用电力来提供输入力或扭矩的工具,小到小家电的生产,大到火箭的制造,都有电动工具的身影。其便携性以及能够提供的大扭力,使得电动工具的需求以及各个领域的应用重要性很高。所以家庭和企业对电动工具的需求也变得越来越大,人们希望自己的工具的耐用性都能达到一定的使用要求。相应地,对电动工具的质量以及可靠性的要求也是越来越大。而跌落冲击所引发的机构毁伤是电动工具的主要失效原因之一。对于结构复杂,材料构成多样的剪切电动工具而言,设计样机-试验与优化的传统方法费时且成本高昂,为满足高效经济的产品研发需要,亟需建立预测跌落冲击响应的新方法。本课题以某品牌电动剪切工具为研究对象,基于冲击理论和有限元理论对其动态缓冲特性和结构优化设计进行了深入研究。主要研究内容如下:(1)运用CATIA和Hyperworks进行几何建模与有限元建模,建立某直流电剪刀的跌落模型。对特定跌落姿态和高度条件下的跌落过程进行仿真,获得了关键冲击应力与结构应变分布,以及零件在跌落后的结果预测;(2)设计跌落试验,记录其在实际跌落过程中的受力状态的变化以及实际的跌落的结果来对比仿真结果,验证数值模型的合理性与适用性;(3)基于电圆锯工具的跌落冲击毁伤现象,采用CAE分析了相应的失效机理。在此基础上,针对护罩结构进行了优化设计,使用CAE来进行模拟及分析,综合比较从而确定最佳优化方案,有效降低了应力集中现象,提高产品的抗跌落冲击性能至安全范围。最后使用优化好的方案进行实际跌落,也来验证CAE模拟的准确性。本文也通过一系列的理论,实践,试验证明了,CAE仿真剪切工具不论从实验结果还是试验中采集的数据,都具有很好的准确度。在项目中,设计中更能够帮助人们进行方案的选择和判断。更多还原

【Abstract】 Powerful tool is one kind of tool that uses electric to offer inputing force or torque,it’s used in a lot of industries,such as digital production,rockets and so on.And because of it’s light weight and big torque offered,the necessary and importance of powerful tool is high in all different kinds of area’s appliance.So a lot of people and companies have the requirement for powerful tool,they hope the production they have has good quality.So for the production of powerful tool,we need to increase the quality and reliability.And Drop impact is one of the main factors leading to the mechanism failure of electric tools.For those individualized electric tools with complex structure composition and diverse materials,traditional method of designing and testing prototypes is time-consuming and costly.Therefore a new prediction method for the drop impact response of electric tools is urgently needed.This paper chose some grand electric tools as the main research objects,and conducted thorough research on their dynamic cushioning property and structural optimization based on the impact theory and the finite element theory.It includes:(1)Using CATIA and Hyperworks to build 3D model and simulate the drop process for one cutting tool.Based on certain dropping angle and height,doing the dropping simulation.Getting the key area’s force and deformation,and predicting the result of dropping;(2)Design the experiment,record the data of dropping and actual dropping result,using these things to compare with the data and result in Dropping simulation,to confirm the simulation’s accuracy;(3)Based on the failure of Circular saw’s actual dropping test,using the CAE to replay the failure and find the root cause(weak point)of the part.Then acrroding to this project’s situation,coming up with some idea to solve the problem.Using CAE to silumate these solution,and compare the data the result of different design’s simulation.From the comparation,choosing the best solution,Apply it to actual production,then do the actual test to confirm it.This paper confirm that,CAE simulation has good accuracy in dropping process data and result by calculation and experiment.And in project,it would help people to analysis and choose the best solution.更多还原