Patent ID: 7703659

Claim:
A friction stir joining apparatus comprising: a rotor having a tip portion; a rotation motor that rotates said rotor about a rotation axis; a straight movement motor that moves said rotor along said rotation axis, said tip portion of a rotating rotor being pressed against an object to be joined so that said object is softened and stirred by a frictional heat at a contact between said tip portion and said object; a rotation control unit that variably controls a rotational speed of said rotor based on a target value for the rotational speed along said rotation axis and controls the target value for the rotational speed to change during a joining operation before the joining operation is complete; a straight movement control unit that controls a straight movement of said rotor so as to control a pressure applied by said rotor to said object based on a target value for a moving speed of said rotor and controls the target value for the moving speed to change during a joining operation before the joining operation is complete; a support member fixedly supporting said rotation motor and said straight movement motor, said rotor being supported by said support member so as to be able to rotate about and move along said rotation axis; a rotation transmitting unit that transmits a rotary power from said rotation motor to said rotor while allowing said rotor to move along said rotation axis; and a straight movement transmitting unit that transmits a straight movement power from said straight movement motor to said rotor while allowing said rotor to rotate about said rotation axis, wherein the joining operation disposes said tip portion of said rotor to be pressed by the straight movement against said object.