Reciprocating linear motion mechanism for can body maker and can body maker

A reciprocating linear motion mechanism of a can body maker, comprising:

• a housing including an internal gear having a first central axis as a center;
• a first rotating body located inside the housing and relatively rotatably joined to the housing;
• a second rotating body including an external gear having a second central axis parallel to the first central axis as a center and meshing with the internal gear and relatively rotatably joined to the first rotating body;
• a ram shaft joining part connected to the second rotating body, having a third central axis parallel to the second central axis as a center, and being linearly moved in a reciprocating manner in a prescribed direction while rotating around the third central axis;
• a valve part connected to the ram shaft j oining part;
• and
• an air supply path passing through insides of the first rotating body, the second rotating body, the ram shaft joining part, and the valve part,
• wherein the valve part has a flow mode in which air is able to pass therein and a cutoff mode in which air is unable to pass therein switched between in accordance with a rotation position around the third central axis of the ram shaft joining part.