大型液压挖掘机工作装置挖掘力分析及机构优化

发布时间：2018-03-25 07:53

本文选题：液压挖掘机　切入点：工作装置　出处：《中南大学》2014年硕士论文

【摘要】：大型液压挖掘机是一种大斗容土石方施工设备,广泛应用于矿山开采及大型工程建设。由于作业过程中挖掘工况的多变性导致工作装置受力复杂,影响整机性能的发挥。本文针对此问题,以70T大型液压挖掘机为样机,建立挖掘机的虚拟样机模型,分析作业过程中工作装置挖掘力及铰点受力的变化,并进行机构优化,以提高挖掘机综合作业性能。主要工作如下：运用D-H法建立工作装置运动学模型,结合工作装置各机构之间的位置关系,得到各机构传动比关系式,建立整机理论挖掘力的计算模型。在Inventor及ADAMS平台中建立挖掘机动力学仿真模型,分析整机理论挖掘力的变化特性及其发挥限制因素所占比重,找出工作装置发挥最大挖掘力时的位姿。在铲斗齿尖加载挖掘阻力,模拟斗杆及铲斗挖掘动作,仿真得到工作装置各铰点的受力变化曲线,对挖掘机工作装置力学性能进行评价,为进一步优化铰点位置提供参考。以铲斗、斗杆理论挖掘力及动臂提升力为目标函数优化工作装置铰点位置。优化结果表明,在小范围内调整铰点位置可有效改善铰点的受力状况,同时提高挖掘机的作业范围。通过测试挖掘机实挖过程中液压缸大小腔压力以及活塞杆位移数据,经过换算得到活塞杆作用力曲线,间接计算出铲斗齿尖挖掘阻力,验证仿真计算模型的准确性。
[Abstract]:Large hydraulic excavator is a kind of construction equipment of large bucket and rock, which is widely used in mining and construction of large scale projects. Because of the variability of excavating conditions during operation, the force of the working device is complicated. In order to solve this problem, this paper takes 70T large hydraulic excavator as prototype, establishes the virtual prototype model of excavator, analyzes the variation of excavating force and hinge force in the working process, and optimizes the mechanism. To improve the comprehensive performance of excavators. The main work is as follows:. The kinematics model of the working device is established by using D-H method. Combined with the position relation of each mechanism of the working device, the formula of the transmission ratio of each mechanism is obtained, and the calculating model of the excavating force of the whole machine theory is established. The dynamic simulation model of excavator is established on the platform of Inventor and ADAMS, and the variation characteristics of theoretical excavating force and the proportion of limiting factors are analyzed. Find out the position and posture of the working device when it exerts the maximum excavating force. Load the excavating resistance at the tip of the bucket tooth, simulate the excavating action of the bucket rod and bucket, and simulate the changing curve of the force at each hinge point of the working device. The mechanical properties of the excavator's working device are evaluated, which provides a reference for further optimization of the hinge position. The theoretical excavating force and lifting force of bucket and bucket bar are taken as objective functions to optimize the position of hinge point of working device. The optimization results show that adjusting the position of hinge point in a small range can effectively improve the stress condition of hinge point. At the same time, the working range of excavator is improved. By testing the pressure of hydraulic cylinder and displacement data of piston rod in the process of excavator, the force curve of piston rod is obtained by conversion, and the digging resistance of bucket tooth tip is calculated indirectly, and the accuracy of simulation calculation model is verified.
【学位授予单位】：中南大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU621

【参考文献】