基于气隙组合永磁弹簧的直动式溢流阀优化设计

航天伺服系统高压大流量的特点，对溢流阀的可靠性、稳压精度和推重比提出了更高的要求。然而大推力下的螺旋压缩弹簧一般体积较大，并且服役期间存在卡死、疲劳断裂、塑性变形等失效模式，给伺服系统带来安全隐患。提出一种基于气隙组合永磁弹簧的直动式溢流阀结构，非接触式的永磁弹簧可避免上述失效和卡死故障，采用气隙组合的优化设计得到了理想的刚度曲线，不仅可有效提高推重比，同时可以减小大刚度带来的开启瞬间压力波动。在此基础上结合有限元仿真与迭代优化，精确设计了凸缘结构来补偿液动力，进一步提高了稳压精度。仿真结果表明，气隙组合永磁弹簧溢流阀具有良好的动静态指标，其设计方法为永磁弹簧在液压系统中的应用提供参考与借鉴。

Optimum Design of Direct Relief Valve with Air Gap Combination of Permanent Magnet Spring

The characteristics of aerospace servo system with high pressure and large flow put higher requirements on the reliability, precision and the thrust weight ratio of relief valve. However, the spiral compression spring with large thrust is generally large, and there are some failure modes such as stuck, fatigue fracture and plastic deformation during the service period, which brings hidden safety troubles to the servo system. A direct relief valve structure with air gap combination of permanent magnet spring is presented. The above-mentioned failures can be avoided because of non-contact permanent magnetic spring. By optimization design of air gap combination the ideal stiffness curve and thrust weight ratio can be effectively improved. Besides, the pressure fluctuation at opening due to large stiffness is reduced at the same time. Furthermore, the flange structure is designed accurately by finite element analysis to compensate the hydrodynamic force. The stabilized pressure precision is further improved. The simulation results show that this novel relief valve has good dynamic and static performance, and its design method provides reference for the application of the permanent magnet spring in the hydraulic system.