电液伺服增压系统的压力冲击抑制方案及特性

Pressure Shock Suppression Scheme and Characteristics of Electro-hydraulic Servo Pressurization System

传统伺服增压系统采用电磁换向阀控制增压缸双向运动,电磁换向阀阀芯位移阶跃变化,导致液压泵变量机构响应不及时而产生大的压力冲击,造成系统中部分元件的损坏并影响系统的正常工作。为此,提出一种液压泵压力主动调控与增压缸位置闭环控制的方法,在液压泵出口增设蓄能器,并使液压泵压力根据增压缸水腔压力实时变化,减小增压缸换向过程压力冲击。建立了所提伺服增压系统的仿真模型,分析伺服增压系统运行特性和所提方案减小压力冲击的效果。结果表明,与传统伺服增压系统相比,采用提出的解决方案,液压泵出口压力冲击由21 MPa减小为14 MPa;增压缸在系统启动过程中的油腔压力冲击由32 MPa降低为7.1 MPa,降低幅度为77.8%;高压运行过程中,油腔压力冲击降低4.5 MPa。同时,所提方案具有良好的节能效果,一个增压周期内,与传统增压系统相比,能耗降低了6.7%。

The traditional servo pressurization system adopts the electromagnetic directional valve to control the two-way movement of the booster cylinder.The step change of the electromagnetic directional valve spool displacement leads to the large pressure impact caused by the untimely response of the hydraulic pump variable mechanism,which causes damage to some components in the system and affects the normal operation of the system.Therefore,a method of active control of hydraulic pump pressure and closed-loop control of booster cylinder position is proposed.Accumulator is added at the outlet of hydraulic pump,and the pressure of hydraulic pump changes in real time according to the pressure of water chamber of booster cylinder to reduce the pressure shock during the commutation of booster cylinder.In the research,the simulation model of the proposed servo pressurization system is established,and the operation characteristics of the servo pressurization system and the effect of the proposed scheme on reducing pressure shock are analyzed.The results show that compared with the traditional servo pressurization system,the outlet pressure shock of the hydraulic pump is reduced from 21 MPa to 14 MPa by using the proposed solution.The oil chamber pressure impact of the booster cylinder during the system start-up process is reduced from 32 MPa to 7.1 MPa,a decrease of 77.8%.During high-pressure operation,the oil chamber pressure shock is reduced by 4.5 MPa.At the same time,the proposed scheme has a good energy-saving effect.In one pressurization cycle,the energy consumption is reduced by 6.7%compared with the traditional pressurization system.