重载柱塞泵球面配流副承载特性研究

Loading characteristics of spherical valve pair in heavy-load axial piston sump

高压(>35 MPa)、大排量(>500 mL/r)的轴向柱塞泵是大断面隧道掘进装备刀盘驱动系统的核心动力源,在高压、大排量的工况下,轴向柱塞泵的配流副油膜是最易损的摩擦副结构,直接影响柱塞泵的可靠性。为此,针对大排量轴向柱塞泵中球面配流副结构的设计问题,对不同结构配流副的承载特性及压力流量特性进行了研究。首先,采用计算流体力学(CFD)方法,构建了轴向柱塞泵整泵的流场模型,对油膜内关键节点的受力及压力流量特性进行了求解,并通过与台架实验的压力出口数据,对比验证了仿真模型边界设置的准确性;然后,对比分析了不同配流副结构的出口压力流量特性,分别对平面配流副、锥面配流副和球面配流副的泄漏特性及其承载特性进行了计算;最后,分析了不同曲率半径的球面配流副在出口压力流量特性、泄漏特性及承载特性方面的差异,提出了球面配流副结构的优化方案。研究结果表明:在泄漏和承载能力方面,球面配流副均优于传统的平面配流副,并且球面曲率半径会直接影响配流副的泄漏和承载特性;针对排量为750 mL/r的大排量轴向柱塞泵,其最优的球面曲率半径为455 mm,此时的脉动率为13.6%,油膜的承载力达76 kN,此时的球面配流副具有最优的承载特性。

The cutter head driving system of the tunnel shield boring machine which has large section(>5 m)played an important role in urban construction.The axial piston pump with large displacement(>500 mL/r)and high pressure(>35 MPa)were required in the cutter head driving system.The friction pair of the valve plate was one of the most vulnerable structure to failure inside the axial piston pump,especially under high pressure and large flow conditions.In this case,the design problem of spherical valve pair structure in large displacement axial piston pump was discussed,the bearing characteristics and pressure flow characteristics of different structure valve pairs were studied.Firstly,the flow field model with oil film was established through the method of computational fluid dynamics(CFD).The force and pressure characteristics sampling points within the oil film were solved by the key points within the model.The accuracy of the boundary setting of the simulation model was verified by comparing with the pressure outlet results of the bench experiment.Then,the influence of different kinds of oil film structures were analyzed,the leakage characteristics and bearing characteristics of planar,conical and spherical valve pairs were calculated and analyzed respectively.Finally,the bearing capacity of different spherical curvatures were analyzed,the outlet pressure-flow characteristics and bearing capacity of different valve plate structure were calculated.The results show that the leakage and bearing capacity of the spherical valve plate is much superior to the traditional planar flow pair.Besides,the spherical radius of the spherical valve plate will directly influence its output performance.With the discussion on the optimization analysis,the optimum spherical curvature radius is 455 mm,the pulsation rate is 13.6%,the bearing capacity of the oil film is 76 kN,which has the optimal bearing capacity.