Composite-machining machine tool

A composite-machining machine tool comprising:

• a bed;
• a table movable relative to said bed in a horizontal Z-axis direction;
• a Z-axis drive device for reciprocally moving said table in the Z-axis direction;
• a headstock mounted on said table;
• a workpiece-holding work spindle rotatably held by said headstock in such a manner that an axis of said work spindle extends in the Z-axis direction;
• a spindle drive device for rotating said work spindle;
• a column fixedly mounted on said bed and having a guide surface extending in an X-axis direction perpendicular to the Z-axis direction;
• an X-axis slide supported on said guide surface of said column so as to move in the X-axis direction;
• an X-axis drive device for reciprocally moving said X-axis slide in the X-axis direction;
• a
• Y-axis slide supported on said X-axis slide so as to move in a Y-axis direction perpendicular to the X-axis and the Y-axis;
• a Y-axis drive device for reciprocally moving said Y-axis slide;
• a B-axis shaft supported on said Y-axis slide for rotation about an axis extending in the Y-axis direction;
• a tool spindle head mounted on a front end of said B-axis shaft, said tool spindle head having a rotatably-supported tool spindle having an axis perpendicular to the Y-axis direction;
• a tool spindle drive device for rotating said tool spindle;
• a B-axis indexing mechanism for indexingly rotating said B-axis shaft;
• a positioning coupling for fixing said B-axis shaft at a plurality of rotational angle positions with respect to said Y-axis slide;
• a clamp piston member provided at said Y-axis slide so as to fix said B-axis shaft at an arbitrary rotational angle position with respect to said Y-axis slide;
• a control device for synchronizing the rotation of said work spindle with the rotation of said tool spindle so as to form gear teeth by hobbing;
• a tool magazine provided above said column;
• and
• an automatic tool exchange device for exchanging a tool in said tool magazine with a tool held by said tool spindle head.