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

A reciprocating linear motion mechanism for a can body maker comprising:

• a housing including an internal gear centered on a first center axis;
• a first rotation body located inside the housing;
• a first bearing connecting the housing and the first rotation body to be relatively rotatable;
• a convex part protruding toward one side direction of an axis direction from a surface of the first rotation body facing toward the one side direction in the axis direction and centered on a second center axis parallel to the first center axis, the axis direction being a direction parallel to the first center axis;
• a second rotation body including an external gear meshing with the internal gear about the second center axis and disposed toward the one side direction from the first rotation body in the axis direction;
• a recess which is recessed toward the one side direction from a surface of the second rotation body facing toward another side direction in the axis direction and into which the convex part is inserted;
• a second bearing connecting the convex part and the recess to be relatively rotatable;
• and
• a ram shaft connection part connected to the second rotation body and moved linearly in a reciprocating manner along a predetermined direction,
• wherein the internal gear, the external gear, the recess, the second bearing, and the convex part overlap each other when viewed from a radial direction orthogonal to the second center axis.