大型液压挖掘机工作装置的联合仿真及静动态特性研究

发布时间：2018-08-29 16:06

【摘要】：大型液压挖掘机是各种大规模露天矿山开采及大型基础建设中广泛使用的工程机械设备,而我国大型液压挖掘机的发展相对落后,与国外相比还有很大差距,国内大型液压挖掘机的发展尚处于起步阶段,目前只有少数厂家可以生产100t以上的液压挖掘机,而国外目前液压挖掘机的机重已达到1000t以上,本文在山西省科技攻关项目“特大型矿用液压挖掘机节能原理及能量效率研究”(20100321025-02)的资助下,对国内目前最大的装机质量达270t的大型液压挖掘机的研究,对国内今后进一步研制更大的液压挖掘机有重要的意义。在270t大型液压挖掘机的研制中,为了能够制定出正确的液压控制方案及选择合适的系统控制参数,对液压挖掘机的挖掘阻力进行了分析计算,建立了液压挖掘机的数学模型,通过所建立的数学模型,对液压挖掘机的平推工况进行了分析计算,对挖掘机斗杆挖掘工况及铲斗挖掘工况的挖掘力进行了分析；采用ADAMS与AMESim两种软件,利用这两种软件各自的优势,对液压挖掘机的工作过程进行了机电液一体化的联合仿真,对液压挖掘机动臂、斗杆、铲斗及开斗液压缸的工作压力、消耗功率及运动速度等参数的变化过程进行了仿真研究,对液压挖掘机工作过程中有关参数的分析计算及计算机仿真研究,为270t大型液压液压挖掘机的研制提供了理论依据。在挖掘机液压控制系统中,采用了多泵供油方式,为了合理分配流量,提高挖掘机的工作效率,动臂、斗杆、铲斗、开斗及行走装置的液压执行机构采用四台主工作泵供油,每台主工作泵通过一组多路阀控制液压执行机构,再通过阀外合流的方式满足这些执行机构单独及复合动作时的速度要求。针对大型液压挖掘机工作过程中能量消耗多,发热量大的问题,在挖掘机液压控制系统中,采用变量泵和比例多路阀结合的方式控制液压执行机构的运动速度,通过正流量控制实现液压泵和多路阀的供需平衡,同时在液压系统中,主工作泵可以实现变功率控制,以适应挖掘机不同工况的要求；此外,为降低挖掘机的使用成本高,270t液压挖掘机的液压控制系统采用电力作为动力源,由交流电动机驱动液压泵组工作。针对动臂和斗杆下降时,由于大型液压挖掘机的机械构件重量重、惯性非常大,导致下降结束阶段压力冲击大、下降速度慢、工作效率低、操作性差的问题,提出动臂和斗杆下降时采用比例再生阀,用流量再生回路实现能量回收,减小压力冲击,加快下降速度,提高挖掘机的操作性能,同时由于下降时无需液压泵供油,提高了液压挖掘机的工作效率,起到了节能的效果,并分析了斗杆采用流量再生回路下降的条件。在制造厂内和液压挖掘机使用的露天煤矿现场,对挖掘机进行了试验研究,对液压挖掘机的工作性能进行了验证,测试了液压挖掘机动臂、斗杆、铲斗及开斗液压缸单动及复合动作时的压力变化,测试了动臂、斗杆分别采用主控阀回路和流量再生回路下降时的压力变化情况及下降所用时间,结果表明,挖掘机加载最大试验负载25t时,所设计的液压控制系统可以完全满足动臂、斗杆、铲斗及开斗加载动作时所需要的压力及速度要求,动臂和斗杆下降采用流量再生回路后,速度明显加快,下降压力更平稳,且下降结束阶段无明显液压冲击。通过试验,验证了挖掘机液压控制方案的正确性,也为国内今后设计和制造更大型的液压挖掘机积累了数据和经验。
[Abstract]:Large-scale hydraulic excavator is widely used in various large-scale open pit mining and large-scale infrastructure construction of engineering machinery and equipment, but the development of large-scale hydraulic excavator in China is relatively backward, compared with foreign countries there is still a big gap, the development of large-scale hydraulic excavator in China is still in its infancy, only a few manufacturers can produce 100t. The above hydraulic excavators, and the weight of hydraulic excavators abroad has reached more than 1000 tons at present, this paper in Shanxi Province science and technology research project "energy-saving principle and energy efficiency of super-large mining hydraulic excavators" (20100321025-02) under the funding of the largest installed mass of 270 tons of large hydraulic excavators in China, the research. It is of great significance to further develop larger hydraulic excavators in China.
In the development of 270t large hydraulic excavator, in order to work out the correct hydraulic control scheme and select the appropriate system control parameters, the excavation resistance of hydraulic excavator is analyzed and calculated, and the mathematical model of hydraulic excavator is established. Through the established mathematical model, the horizontal push working condition of hydraulic excavator is divided. Based on the analysis and calculation, the excavating force of bucket-bar excavation and bucket excavation of excavator is analyzed. Using ADAMS and AMESim software and their respective advantages, the working process of hydraulic excavator is simulated by electro-hydraulic integration, and the work of arm, bucket-bar, bucket and bucket cylinder of hydraulic excavator is simulated. The variation process of parameters such as working pressure, power consumption and moving speed is simulated. The analysis and calculation of relevant parameters in the working process of hydraulic excavator and the computer simulation study provide a theoretical basis for the development of 270t large hydraulic excavator.
In order to distribute the flow reasonably and improve the working efficiency of the excavator, the hydraulic actuator of the boom, bucket bar, bucket, bucket opening and running device adopts four main working pumps to supply oil. Each main working pump controls the hydraulic actuator through a set of multi-way valves, and then merges with the valve outside. The method meets the speed requirements of these actuators in separate and compound movements.
Aiming at the problem of high energy consumption and high calorific value in the working process of large hydraulic excavator, variable pump and proportional multi-way valve are combined to control the movement speed of hydraulic actuator in the hydraulic control system of excavator, and the supply and demand balance of hydraulic pump and multi-way valve is realized by positive flow control. As a pump, variable power control can be realized to meet the requirements of different working conditions of the excavator. In addition, in order to reduce the cost of using the excavator, the hydraulic control system of 270t hydraulic excavator uses electric power as the power source, and the hydraulic pump group is driven by AC motor.
In view of the heavy weight and great inertia of the mechanical components of the large hydraulic excavator when the boom and bucket rod descend, which leads to large pressure impact, slow descent speed, low working efficiency and poor operability at the end of the descent stage, the proportional regeneration valve is used to realize energy recovery and reduce pressure when the boom and bucket rod descend. The impact accelerates the descending speed and improves the operation performance of the excavator. At the same time, the working efficiency of the hydraulic excavator is improved and the energy-saving effect is achieved because the hydraulic pump is not needed to supply oil when descending. The descending condition of the flow regeneration loop of the bucket rod is analyzed.
In the open pit coal mine where the hydraulic excavator is used in the factory and in the open pit coal mine, the excavator is tested, and the working performance of the hydraulic excavator is verified. The pressure changes of the hydraulic excavator arm, bucket bar, bucket and open bucket hydraulic cylinder under single and compound action are tested, and the moving arm is tested. The bucket bar adopts the main control valve circuit and the main control valve circuit respectively. The results show that the designed hydraulic control system can fully satisfy the pressure and speed requirements of the boom, bucket bar, bucket and open bucket when the maximum test load of the excavator is 25T. When the boom and bucket are lowered by the flow regeneration loop, the pressure and speed requirements of the boom and bucket can be fully met. Experiments have proved the correctness of the hydraulic control scheme of excavators and accumulated data and experience for the design and manufacture of larger hydraulic excavators in the future in China.
【学位授予单位】：太原理工大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TU621

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