Hole drilling machine and method for drilling oval hole and inner-diameter-changing hole by means of hole drilling machine

Abstract

Provided is a hole drilling machine and the method for drilling an oval hole and an inner-diameter-changing hole by means of the hole drilling machine, the machine and the method being configured so that the oval hole can be shaped with high accuracy and drilling of a complicated hole such as the inner-diameter-changing hole can be performed with high accuracy. A hole drilling machineincludes a spindleand an auxiliary spindleholding both end portions of a processing toolhaving a cutting blade. The spindleincludes a spindle drive motorconfigured to rotatably displace the processing toolon a circular path, and a tool turnable-drive motorconfigured to spin the processing tool. The auxiliary spindleincludes an auxiliary spindle drive motor. In the auxiliary spindle drive motor, a tool fitting portionin which a tip end portion of the processing toolis slidably fitted is synchronously rotatably driven on the same circular path as that for the spindle. A table reciprocatably-displacing mechanismis provided between the spindleand the auxiliary spindle. The table reciprocatably-displacing mechanismreciprocatably displaces a work piece WK in an X-axis direction perpendicular to an axial direction of the spindle