精密宏微驱动回转系统大载荷支承结构设计与性能分析

Design and Performance Analysis of Heavy-load Support Structure for Precision Macro-micro Drive Rotary System

摘要:

宏微驱动系统可有效解决数控转台因精密电机自身固有最小运动误差限制而无法实现亚角秒级精密定位问题，然而数控加工需承受大载荷，限制了宏微驱动回转系统在数控转台上的应用。针对上述问题，本文设计了一种大载荷宏微驱动回转系统轴向支承结构，可有效承载系统轴向载荷，并研究该支承结构载荷性能。设计了一种宏微驱动回转系统，在建立系统复合载荷力学模型基础上分析了系统载荷性能，提出了单排四点接触式回转支承作为系统轴向支承结构设计方案，并完成了回转支承结构参数设计及大载荷宏微驱动回转系统轴向支承工作原理分析；采用赫兹接触理论和有限元法完成了对回转支承内外滚道上的接触应力分析，结果显示回转支承具有良好的承载力、可满足设计要求；采用理论计算、有限元法和实验验证3种方法完成了回转支承的大载荷承载性能分析，结果表明大载荷宏微驱动回转系统在最大轴向输入载荷1 500 N下轴向承受载荷最大为9.88 N、最大轴向承受载荷误差为0.69%，证明了大载荷宏微驱动回转系统支承结构设计的有效性及精密性。研究结果对推动亚角秒级数控转台及宏微驱动回转系统研究具有重要意义。

Abstract:

The macro-micro drive system effectively addresses the challenge of achieving sub-arc-second precision positioning in CNC rotary tables, a limitation imposed by the inherent minimum motion error of precision motors. However, its application in CNC rotary tables is restricted by the need to withstand heavy loads during machining. To tackle this issue, an axial support structure for a heavy-load macro-micro drive rotary system capable of effectively carrying the system's axial loads was designed, and systematically investigated the load performance of this support structure. A macro-micro drive rotary system was developed. Based on a mechanical model established under combined loads, the load performance of the system was analyzed. A single-row four-point contact slewing bearing was proposed as the axial support structure, and both its structural parameters and the working principle of the axial support for the heavy-load macro-micro drive rotary system were determined. Subsequently, contact stress analysis on the inner and outer raceways of the slewing bearing was performed by using Hertz contact theory and the finite element method (FEM). The results indicated that the slewing bearing exhibited excellent load-bearing capacity, satisfying the design requirements. Finally, the heavy-load bearing performance of the slewing bearing was evaluated through three complementary approaches: theoretical calculation, FEM simulation, and experimental validation. The results showed that under a maximum axial input load of 1,500 N, the heavy-load macro-micro drive rotary system beared a maximum axial load of 9.88 N, corresponding to a relative error of 0.69%. These findings demonstrated the effectiveness and precision of the designed support structure for the heavy-load macro-micro drive rotary system. This research was of significant importance for advancing the development of sub-arc-second CNC rotary tables and macro-micro drive rotary systems.