轴向柱塞液压马达机械液压耦合仿真分析

Simulation Analysis of Axial Piston Hydraulic Motors by Mechanical Coupling with Hydraulic

为了使轴向柱塞液压马达仿真模型接近于物理样机,采用机械、液压耦合模型并综合考虑柱塞和缸体、柱塞和斜盘等摩擦副的摩擦力和液体的粘性阻尼以及减小压力脉动的三角阻尼槽等因素,建立了轴向柱塞液压马达仿真模型。液压马达高压油推动柱塞位移、机械能推动柱塞排油,实现液压能和机械能相互转换,主要包括压力源(恒流源或恒压源)、负载(外部阻力矩,转动惯量)、柱塞缸体组件、柱塞往复和旋转运动转换组件、配流窗口等。仿真结果与有关文献中液压马达实验数据进行对比,马达转速、加速时间、最大输出流量的仿真值与实验值误差均小于5%,验证了仿真模型能够保证较好的计算精度。仿真结果表明,由于卸荷槽和腰型槽过渡区域有通流面积突变现象,容易产生局部压力脉冲现象,且转速越高压力波动越大,通过优化卸荷槽结构型式和参数可以减小脉动冲击;液压马达工作特性受负载的影响,负载的总转动惯量大时加速时间长而稳定转速波动区间窄,相应产生的脉动也趋于减小。

In order to make the simulation model closer to physical prototype,mechanical hydraulic coupling simulation model on axial piston hydraulic motor was established,and the factors including the friction force of cylinder plunger and cylinder block,cylinder plunger and swash plate,the viscous damping of fluid and the triangle damping groove which is to decrease the pressure fluctuation were taken into consideration. Through the high pressure oil of the hydraulic motor pushing plunger to move and mechanical energy driving plunger to discharge oil,the mutual conversion between hydraulic energy and mechanical energy was implemented. The simulation model mainly included the pressure source（ constant current source or constant voltage source）,load（ external resistance moment）,piston and cylinder components,reciprocating and rotating motion transformation components of the plunger,oildistribution port,etc. In the model,cylinder was connected with rigid or elastic locking device. Piston and cylinder surface is simplified to a spring-damper elastic sealing unit. In order to realize positive inversion of the hydraulic motor,triangle unloading groove was set in the both ends of the oil inlet and outlet of the valve plate. Through the contrast between simulation result and experimental data from literature,it can be found that the errors of motor speed,acceleration time and maximum flow output are less than 5%. The accuracy of simulation model was testified. According to the simulation result,onaccount of the flow area mutation of the unloading groove and the waist type slot transitional region,there is a local pressure pulse; and the higher rotational speed is,the greater pressure fluctuation is. The pulsating pressure could be alleviated through improvement of structure and optimization of parameters of the load discharging groove. The performance characteristic of hydraulic motor will be affected by load,when the moment of inertia of load is high,the acceleration time will be long,the fluctuating region of steady rotational speed will be narrow,and the corresponding impulse will be smaller.