Hinge module and foldable electronic device including the same

A hinge module comprising:

• a first fixed structure including a first central portion, a first support portion extending from the first central portion in a first direction, and a first guide portion extending from the first support portion in a third direction perpendicular to the first direction;
• a first connecting shaft including a first gear formed on at least a central part of an outer circumferential surface thereof, the first connecting shaft extending in the first direction, wherein at least a part of the first gear is disposed between the first central portion and the first guide portion;
• a first sub-gear engaged with the first gear, wherein the first fixed structure includes a first guide structure formed on the first central portion and a second guide structure formed on the first guide portion;
• a first rotary structure, including a first guide rail having a first radius of curvature coupled to the first guide structure and a second guide rail having a second radius of curvature coupled to the second guide structure, the first and second radii of curvature defined with respect to a first axis of rotation wherein the first rotary structure is configured to be rotated about the first axis of rotation while the first connecting shaft rotates, at least a portion of the first rotary structure is disposed between the first guide portion and the first central portion;
• a second fixed structure including a second central portion coupled to one side of the first central portion that faces a second direction opposite to the first direction, a second support portion extending from the second central portion in the second direction, and a second guide portion extending from the second support portion in a fourth direction perpendicular to the second direction, the second fixed structure includes a third guide structure formed on the second central portion and a fourth guide structure formed on the second guide portion and the second fixed structure being integrally or removably coupled to the first fixed structure;
• a second connecting shaft including a second gear formed on at least a central part of an outer circumferential surface thereof, the second connecting shaft extending in the second direction, wherein at least a part of the second gear is disposed between the second central portion and the second guide portion;
• a second sub-gear engaged with the second gear, wherein the first connecting shaft and the second connecting shaft are linked with each other by the first sub-gear and the second sub-gear so as to be rotated in opposite directions;
• and
• a second rotary structure including a third guide rail having a third radius of curvature coupled to the third guide structure and a fourth guide rail having a fourth radius of curvature coupled to the fourth guide structure, the third and fourth radii of curvature defined with respect to a second axis of rotation, wherein the second rotary structure is configured to be rotated about the second axis of rotation while the second connecting shaft rotates, at least a portion of the second rotary structure is disposed between the second guide portion and the second central portion,
• wherein the second axis of rotation is parallel to a longitudinal center line of the hinge module and is offset from the longitudinal center line by a first predetermined distance on one side of the longitudinal center line, and the first axis of rotation is parallel to the longitudinal center line and is offset from the longitudinal center line by a second predetermined distance on another side of the longitudinal center line.