Abstract: This research aims to address the issues of low machining efficiency, short tool life, and poor hole surface quality in the processing of large-diameter deep holes (diameter D=30~80 mm, aperture L/D=5~12) in automotive transmission housings. Traditional deep hole drills face challenges such as difficult chip evacuation, insufficient cooling, and unstable centering when processing largediameter deep holes. To address the shortcomings of traditional deep hole drills in large-diameter deep hole machining, such as poor chip evacuation, insufficient cooling, and unstable centering, this research proposes a novel and efficient machine-clamped deep hole drill design. Innovatively, the design features a dense arrangement of large and small inserts, combined with a supporting guide strip and a straight flute chip evacuation channel, which significantly enhances tool rigidity and machining stability. Comparative experiments have shown that the new tool, when machining QT400 material, achieves a significant reduction in hole surface roughness, a 1.5-fold increase in tool life, and a 50% improvement in machining efficiency. This study provides an efficient, low-cost, and reliable tool solution for large-diameter deep hole machining, offering significant engineering application value in advancing the manufacturing technology of key automotive components.

Key words: transmission; large-diameter deep hole; machine-clamped deep hole drill; dense tooth arrangement; protruding triangular insert

摘要： 研究旨在解决汽车变速箱壳体中大直径深孔（直径 D=30～80 mm，孔径 L/D=5～12） 加工效率低、刀具寿命短、孔表面质量差等问题。针对传统深孔钻头在大直径深孔加工中存 在排屑困难、冷却不足、定心不稳等缺陷，研究提出一种新型高效机夹深孔钻设计方案。刀 体为一体化设计，引入凸三角形标准刀片，创新性地采用大小刀片密齿排布结构，配合支撑 导条导向与直槽排屑通道，显著提升了刀具刚性与加工稳定性。通过对比试验验证，该新型 刀具在加工 QT400 材料时，孔表面粗糙度显著降低，寿命提升约 1.5 倍，加工效率提升 50%。 研究为大直径深孔加工提供了一种高效、低成本、可靠的刀具解决方案，对推动汽车领域关 键零部件的制造技术进步具有重要工程应用价值。

关键词: 变速箱；大直径深孔；机夹深孔钻；密齿排布；凸三角形刀片