Apparatus And Method For Drilling A Work

A method for drilling a workpiece comprising:

• providing a shaft portion including a holder for holding a drilling tool rotating around a first axis;
• a reduction gear connected to the shaft portion;
• a cylindrical member including an outer cylinder and an inner cylinder for rotatably containing the shaft portion at an eccentric position, said cylindrical member connected to an output shaft of the reduction gear and rotating around a second axis parallel to the first axis, a slide containing cylinder for containing the shaft portion, the reduction gear and the cylindrical member, said slide containing cylinder including a sliding structure for axially moving the shaft portion, the reduction gear and the cylindrical member;
• and
• drilling a workpiece while simultaneously rotating the drilling tool around the first axis, revolving the drilling tool around the second axis and axially moving the drilling tool;
• rotating the drilling tool by rotating the shaft portion and rotating the input shaft of the reduction gear;
• simultaneously rotating the cylindrical member, connected to the output shaft of the reduction gear, around the second axis at a predetermined reduction ratio.