小型液压挖掘机电驱动动力源特性研究

Electric Drive Hydraulic Power Source Characteristics of Small Hydraulic Excavator

传统液压挖掘机多采用定转速柴油发动机驱动液压泵作为动力源,针对发动机经常工作在低效区,油耗大、能效低、排放严重等问题,提出一种变转速感应电动机驱动变量泵动力源,以变量泵快速响应特性弥补变转速电动机动态响应慢的不足。为了充分了解所设计的电液动力源特性,从理论和试验两个方面研究了电液动力源动静态特性。与传统发动机驱动液压泵动力源系统进行了测试对比,结果表明,设计的变转速变排量动力源在负载扰动测试中转速波动降低了23.5%,在动臂举升过程中,泵输出压力和流量的上升时间分别缩短了14.9%和26.3%,均优于传统发动机驱动液压泵动力源。

Hydraulic excavator driven by an internal-combustion engine is widely used in the construction field.As engine often works in inefficient area,some problems,such as high pollutant emissions,noise and low efficiency exist universally.In order to improve energy efficiency and reduce the emissions,applying hydraulic power source driven by electric motor to hydraulic excavator has become an important research direction.A power source was presented with variable speed induction motor to drive variable displacement pump,which used the fast response characteristic of variable displacement pump to make up for the slow dynamic response of variable speed induction motor,and it was applied to excavator.In order to fully understand the characteristics of the designed electro-hydraulic power source and provide a reference for electric hydraulic excavator design,the dynamic,static and disturbance characteristics of electro-hydraulic power source were studied from both the perspectives of theory and experiment.Then,load disturbance test and arm lifting test were completed on the test rig under the same working conditions.Compared with the characteristics of traditional engine used to drive hydraulic power source system,the new variable speed-variable displacement power source reduced the rotation speed fluctuation by 23.5%in the load disturbance test,the rising time of pump output pressure and flow was reduced by 14.9%and 26.3%in the arm lifting process.The new electro-hydraulic power source owed better characteristics.