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

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