基于加工过程的螺旋曲面精密成型刀具齿形优化设计理论研究

Aiming at the problem of low tooth surface precision of screw rotors which causes the poor performance of screw machines, such as low volumetric efficiency and unstable operating condition, optimization design method of form cutter is proposed based on machining process of screw helical surface, in which comprehensive affecting factors are taken into account, such as geometry and process parameters of cutter, vibration, deformation and wear of cutter, so that the tooth profile of forming tool can be optimized based on forming process. This project combines conjugate surface forming theory and forming milling theory to carry out research on mapping relationship between parameters of cutter and screw surface quality, the milling dynamics and stability, mechanism of cutter’s deformation and wear, and optimization method of cutter’s parameters. Then the quantitative relation between geometric parameters, vibration, deformation, wear of forming tool and the machining precision can be obtained, and also the effect of forming tool’s feed rate and rotate speed on the amount of deformation and wear can be validated. After that, the accuracy of forming tool design will be improved, while helical surface error of screw rotors during forming process will be reduced which guarantees the machining precision. Based on machining process, this research will lay the foundation for optimization design theory of precision forming cutter’s tooth profile as well as machining specification of screw helical surface.

针对螺杆齿面精度低导致螺杆机械容积效率、可靠性等综合性能低的难题，考虑刀具几何及工艺参数、振动、刀具变形及磨损等综合影响因素，提出基于加工过程的螺旋曲面精密成形加工优化设计方法，实现基于加工过程的成型刀具齿形优化设计。项目将共轭曲面创成理论、成型铣削理论等理论与分析方法相结合，开展刀具齿形误差及工艺参数与螺旋曲面质量的映射规律、铣削动力学及稳定性、刀具变形及磨损机理、刀具参数优化方法等研究，探明刀具几何参数、振动变形、磨损与齿面加工精度之间的定量关系；揭示进给量、转速等与刀具变形量、磨损量之间的作用机理，提高成型刀具设计的精确性，降低螺杆成形加工过程的齿面误差，保证了螺旋曲面的加工精度，为形成基于加工过程的螺旋曲面精密成型刀具齿形优化设计方法与加工规范奠定基础。

本项目以摆线型螺杆泵转子型线的优化设计与精密成形加工技术为研究对象，利用数值分析、空间啮合原理与包络理论、成形磨削原理等理论工具，深入研究螺杆转子啮合间隙设计方法、成形刀具优化设计方法、成形磨削误差补偿、螺杆型面粗糙度控制以及检测技术等螺杆转子设计与精密加工的技术难点。本项目主要工作如下：.① 在研究摆线生成原理的基础上，对摆线型双螺杆泵齿形和摆线型三螺杆泵齿形进行设计。利用空间解析几何知识对螺杆转子不同啮合间隙设计方法进行对比分析，并通过计算机CFD数值仿真比较了不同间隙数值对摆线型双螺杆容积效率的影响规律，并根据实际工况需求对螺杆泵啮合间隙进行设计，成形一套面向可制造与自适应的螺杆转子齿形优化设计方法。.② 研究螺杆转子成形加工中螺杆型面坐标系与成形刀具坐标系相互转化关系，基于空间啮合原理与包络理论，运用三次样条插值法实现基于离散点数据的螺杆转子成形刀具廓形求解。基于MATLAB GUI开发了一套可以用螺杆转子型线数据预处理、啮合间隙设计、成形刀具设计、成形仿真加工、误差评估的可视化软件。.③ 研究螺杆转子成形砂轮的磨损机理，通过螺杆转子成形仿真加工，揭示成形砂轮安装中心距、安装角以及砂轮磨损对螺杆转子廓形误差的影响规律，创新性地提出了一种通过安装参数调整法实现对砂轮磨损致廓形误差进行补偿，并通过仿真加工验证所提出的误差补偿方法的可行性与正确性。深入研究螺杆转子成形磨削机理，首次建立了光整磨削阶段的螺杆型面磨削粗糙度预测模型。.④ 螺杆转子的精密成形加工离不开高精度的检测技术，检测精度在很大程度上决定了螺杆转子加工精度的提升。在本项目中提出了一种通过齿轮测量中心二维截面测量实现螺杆型面三维表征的新方法，克服了通用检测设备无法实现螺杆转子精确检测的技术难题，对于提升螺杆转子检测效率、降低检测成本、提高螺杆转子加工精度具有重要意义。