Rotating tool, joining device, and joining method

A rotating tool used in a joining device configured to perform friction stir welding of to-be-joined members, the rotating tool comprising:

• a main body including a fixation portion that is attached and fixed to the joining device and a rotating shaft that transmits rotating force from the joining device;
• a stir member including a stir pin that performs friction stirring on the to-be-joined members by being inserted into the to-be-joined members, the stir member provided to be rotatable by receiving the rotating force from the rotating shaft and provided in the main body to be movable in an axial direction of the rotating shaft;
• an elastic member configured to bias the stir member toward a distal end side in the axial direction of the rotating shaft;
• and
• a restriction member configured to restrict movement of the stir member toward a base end side in the axial direction of the rotating shaft, wherein
• the restriction member restricts the movement of the stir member such that an amount of deformation occurring in the elastic member with the movement of the stir member does not exceed a maximum allowable amount of the elastic member;
• the main body further includes a holder that has a hollow tube shape and that is attached to the rotating shaft and a slide shaft that is housed in a center portion of the holder to be slidable in a rotating shaft direction and that rotates in synchronization with the holder,
• the stir member is provided at a distal end of the slide shaft,
• the slide shaft is biased toward a distal end side of the stir member via the elastic member, and
• the restriction member restricts movement of the slide shaft toward the base end side in the axial direction of the rotating shaft;
• and
• one of the following:
• i) the restriction member is provided in the holder, and the movement of the slide shaft is restricted by contact of a base end portion of the slide shaft and a bottom portion of the holder on the base end side with the restriction member that occurs with the movement of the slide shaft;
• ii) the restriction member is provided in a bottom portion of the holder on the base end side, and the movement of the slide shaft is restricted by contact of a base end portion of the slide shaft with the restriction member that occurs with the movement of the slide shaft;
• iii) the restriction member is provided in a base end portion of the slide shaft, and the movement of the slide shaft is restricted by contact of a bottom portion of the holder on the base end side with the restriction member that occurs with the movement of the slide shaft;
• iv) the restriction member is provided on an outer peripheral surface of the slide shaft, and the movement of the slide shaft is restricted by contact of the restriction member with an intermediate portion of the holder that occurs with the movement of the slide shaft;
• v) the restriction member is provided on an outer peripheral surface of the slide shaft, and the movement of the slide shaft is restricted by contact of the restriction member with a distal end portion of the holder that occurs with the movement of the slide shaft;
• vi) the restriction member is provided in a distal end portion of the slide shaft, and the movement of the slide shaft is restricted by contact of the restriction member with a distal end portion of the holder that occurs with the movement of the slide shaft;
• vii) the stir member is the restriction member, and the movement of the slide shaft is restricted by contact of the stir member with a distal end portion of the holder that occurs with the movement of the slide shaft.