双缸变幅机构负载下降时的同步特性研究

Research on Synchronization of Two-Cylinder Luffing Mechanism at Decline Stage

双平衡阀控双缸变幅机构在负载下降时,由于左右平衡阀结构参数的差异,容易出现双缸不同步现象;以280k N·m旋挖钻机为例,建立了平衡阀的数学模型和动臂变幅机构液压系统的AMESim仿真模型;仿真分析的结果表明了左右平衡阀控制阻尼孔的差异会导致变幅双缸在负载下降过程中出现不同步,而导压比、调压弹簧预紧力的差异会导致双缸开启不同步;进而提出了双缸无杠腔连通加防爆阀的解决方案,并通过仿真与实验证了其有效性,对解决双缸变幅时的不同步问题具有一定指导意义。

At the decline stage of the two - cylinder luffing mechanism controlled by two counterbalance valves, the movements of the two cylinders can hardly be synchronous due to the parametric differences between the left and right counterbalance valves. To tackle this, the hydraulic system of the boom luffing mechanism of a 280kN · m rota- ry drilling rig was studied in this paper. A mathematical model of the counterbalance valve was established and a sim- ulation model of the hydraulic system of the boom luffing mechanism was built with AMESim. The simulation results show that the difference of the damping holes of the control oil circuit can cause asynchronous movement of the two cylinders when declining and the differences of the pressure conductivity coefficients and the spring preloads generate asynchronous movement of the two cylinders when opening. An improvement strategy of connecting the chambers without piston of the two cylinders with anti - explosion valves was developed and proved to be effective through simu- lation and experiment, which is instructive to solve the asynchrony problem of two cylinders when luffing.