Arm structure, hinge structure including the arm structure, and electronic device including the same

A foldable electronic device comprising:

• a housing including a first housing part and a second housing part;
• a hinge structure connected to the first housing part and the second housing part,
• wherein the hinge structure includes:
• a first rotating shaft configured to rotate about a first axis;
• a second rotating shaft configured to rotate about a second axis;
• a first cam connected to the first rotating shaft and including at least two peaks;
• a second cam connected to the second rotating shaft and including at least two peaks;
• a third cam engaged with the first cam and including at least two peaks;
• and
• a fourth cam engaged with the second cam and including at least two peaks;
• and
• a flexible display disposed on the first housing part, the hinge structure, and the second housing part,
• wherein the display is configured to exert a restoring force from a folded state to an unfolded state when the housing is in an at least partially folded state,
• wherein the first cam is configured to rotate in a first direction and the second cam is configured to rotate in a second direction, the second direction being opposite with respect to the first direction, as the restoring force is applied to the hinge structure,
• wherein central portions of the peaks of the first cam and the fourth cam are inclined such that second sides thereof that face the second direction are higher than first sides thereof that face the first direction, and
• wherein central portions of the peaks of the second cam and the third cam are inclined such that second sides thereof that face the second direction are lower than first sides thereof that face the first direction.