Abstract: In this paper, the loss of heavy-duty cutting function and finishing ability before the transformation of the main drive system of the TH42250 CNC gantry machining center is analyzed, and the overall transformation design scheme of the box structure, shaft, gear and assembly is proposed in terms of improving accuracy, strength and materials. Through the processing, assembly and operation of new spare parts, good results are achieved, and success are achieved in terms of operation stability, temperature rise control, processing accuracy, cost control, and maintenance cost savings. The heavy-duty cutting function and machining accuracy of the equipment returned to the factory design level, which could be used for reference in the fault repair of other main transmission systems and the design and development of gearboxes.

Key words: Heavy-duty cutting; Rigid; Gear transmission; Roughness

摘要： 文章通过对 TH42250 数控龙门加工中心主传动系统改造前的重载切削功能丧失和精加 工能力丧失的问题进行分析，在提高精度、强度和改善材料等方面，对箱体结构、轴、齿轮、 装配等提出了整体的改造设计方案。通过新备件的加工、装配及运行，取得了良好的效果， 在运行的稳定性、温升控制、加工精度、成本控制、维护费节省等方面取得了成功。设备重 载切削功能和加工精度恢复出厂设计水平，对其他主传动系统的故障修复和齿轮箱设计研发 起到借鉴作用。

关键词: 重载切削；刚性；齿轮传动；粗糙度