| 摘要 |
PROBLEM TO BE SOLVED: To provide a tool holder high in rigidity and high in balance even when a reach is long, and capable of performing highly efficient processing.SOLUTION: The tool holder A1 includes a shank part 10 and a holder part 20, a columnar hard metal bar 30 is included in the axis of both by shrink fitting, and the holder part is divided into 20and 20at the middle of the hard metal bar. The coupling of the hard metal bar to the holder part and the shank part by the shrink fitting is higher in positioning accuracy (gripping accuracy) at each stage than other methods such as press fitting. This tool holder is useful when the ratio of (projection length L from machine main spindle end surface)/(hard metal bar diameter D2) exceeds 3 with the neck diameter of the holder part set to D1. A hole 33 is provided through both end surfaces on the center axis of the hard metal bar. By this through-hole, the hard metal bar can be reduced in weight and cost while maintaining rigidity, and the hole can be used as a passage for supplying coolant liquid.SELECTED DRAWING: Figure 1 |
