【作者】 张爱宾；

【导师】 苗明；

【作者基本信息】 大连理工大学 ， 机械工程， 2012， 硕士

【摘要】 液压挖掘机是一种可以实现多种功能的工程施工机械产品,实际作业除包括常见的常规挖掘外,还可以更换工作装置以此实现夯实地面、击碎岩石、起吊重物、破碎、打桩、钻孔等功能,广泛应用在桥梁建设、道路铺设、房地产开发、国防工程等土石方施工和抗震抢险之中,有“工程机械之王”的美誉。工作装置是液压挖掘机的主要结构部件,其设计的合理与否将直接关系到整体性能及使用寿命,因此各个生产制造商一直高度重视工作装置的设计。由于挖掘机工作环境和作业条件相对恶劣,作业姿态多变,工作装置结构多承受动载荷,因此挖掘机整机在服役一定时间后结构会出现局部甚至整体的破裂。但挖掘机工作装置多是箱型结构,由不同厚度,不同形状的钢板拼接而成,传统的手工计算方法对于这种复杂结构只能简化计算,且不能得到整机任一处的应力状态。鉴于此,本文以某公司45t液压挖掘机为对象做了如下研究：(1)针对挖掘机结构形式及液压系统原理,拟定挖掘机结构应力试验和液压缸油压及位移试验方案,获得了结构关键位置处的应力数据及液压油缸的压力和位移数据。(2)借助有限元分析软件ANSYS建立了挖掘机有限元模型,进行整机结构有限元分析,并与对应工况试验测得数据进行比较验证,最后计算危险姿态下结构应力水平。(3)针对部件结构应力分布不合理处(包括应力集中、局部结构应力分布不均匀等)进行局部刚度的研究,并进行结构改进,使应力分布趋于缓和。(4)对影响疲劳及结构强度的焊缝进行不同长高比、不同长宽比等结构型式的研究,最终得出受力分布较为理想的结构型式。更多还原

【Abstract】 Hydraulic excavator is a versatile production of construction machinery, including the conventional digging job, firmed up ground, crushed rock, lifting heavy item, crushing, piling, drilling and many other functions by replaced the device. It’s widely used in the construction of water conservancy facilities, road construction, building construction, port construction, defense, engineering, earth and stone construction and earthquake rescue, known as’The king of construction machinery’Working device is one of the main devices of the hydraulic excavator, whether the design of structural is reasonable or not will directly affect the overall performance and service life of the machine, the design of work equipment has always been attacked much attention of many manufacturers. Because of the relatively poor working environment operating conditions and variations working attitude and the working device boring more dynamic loads, structure of the excavator will be ruptured in local or even the entire after a certain time in the service. But the working device is a type of box structure which is made of the steel plates of different thickness and shapes. Traditional manual calculation method for this complex structure can only simplify the calculation, and any of the stress state of the machine can not be got. In view of this, the following research were made by45t hydraulic excavators of a company in this article.(1) According to the structure and principle of the hydraulic system of hydraulic excavator, the test scheme of the structure stress and pressure and displacement of hydraulic cylinder were made, key position’s stress data of the structure and the date of hydraulic pressure and displacement were obtained.(2) The finite element model of excavator for structural finite element analysis were made with the finite element analysis software ANSYS, and the simulated results were compared with the test results of corresponding working conditions and verified, the stress level of structural in the dangerous attitude was calculated at last.(3) The local stiffness of the components of structural whose stress distribution is unreasonable was researched (including stress concentration, uneven distribution of local structural stress), and the structural was improved to relax the stress distribution.(4) The weld which influences the fatigue life and structural strength in different length height ratio, different width ratio and different structure type was researched. Finally a more ideal structure was obtained.更多还原